JP2010153806A - Back surface protective film for solar cell and solar cell module including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a back surface protective film for solar cells that embeds a solar cell element and is excellent in adhesion properties to filler sections including ethylene-vinyl acetate copolymer compositions, or the like, heat resistance, flexibility, and weather resistance, and to provide a solar cell module including the back surface protective film for solar cells. <P>SOLUTION: The back surface protective film (1A) for solar cells successively includes first, second, and third resin layers (11), (12), (13). The first resin layer (11) includes silicon-containing thermoplastic resins. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a back surface protective film for a solar cell and a solar cell module including the same, and more specifically, has excellent adhesion to a filler part of a solar cell module including an ethylene / vinyl acetate copolymer composition and the like. The present invention relates to a solar cell back surface protective film and a solar cell module using the same.

  In recent years, a photovoltaic power generation system including a solar cell module has become widespread as one of power generation means using clean energy. In the solar cell module, a large number of plate-like solar cell elements are arranged, and these are wired in series and in parallel, and packaged to protect the elements and unitized. And this solar cell module usually uses a composition containing an ethylene / vinyl acetate copolymer having a high transparency and excellent moisture resistance by covering the surface of the solar cell element that is exposed to sunlight with a glass plate. Then, after the gap around the solar cell element is filled to form the filler portion, the back surface, that is, the exposed surface of the filler portion is sealed with a protective film made of a resin material.

As a back surface protective film for a solar cell, a film containing a fluororesin, a polyethylene resin, a polyester resin, or the like has been conventionally known. An easily-adhesive film having an adhesive layer on one side has been studied.
Patent Document 1 discloses a solar cell in which a base film made of polyethylene terephthalate is provided with a thermal adhesive layer including a styrene / olefin copolymer having thermal adhesiveness with a polyolefin resin such as an ethylene / vinyl acetate copolymer. A backside sealing film is disclosed.
Patent Document 2 discloses a film in which a coating layer containing a polyurethane-based resin or an organosilane compound is formed on a base film made of polyethylene terephthalate.
Patent Document 3 includes a polyester film containing an ethylene terephthalate unit, and a coating containing a crosslinking agent, a polyester resin having a glass transition point of 20 ° C. to 100 ° C., an acrylic resin, and the like. The polyester film for solar cell back surface protective films provided with the coated film was disclosed.

JP 2003-60218 JP 2006-175664 A JP 2007-268710 A

As described in Patent Documents 1 to 3, when a film having an adhesive layer is used, a certain adhesiveness with a filler part containing an ethylene / vinyl acetate copolymer composition is obtained. A process of forming is separately required, and defects due to coating unevenness may occur, so that the protection of the filler portion is not always satisfactory.
An object of the present invention is a film that does not have an adhesive layer for adhering to a filler part that embeds a solar cell element on the surface thereof, and has adhesion to the filler part that embeds the solar cell element. An object of the present invention is to provide a solar cell back surface protective film excellent in heat resistance, weather resistance and flexibility and a solar cell module including the same.

In addition, as described above, the solar cell module is formed by arranging a large number of plate-like solar cell elements, and the sunlight is applied to the back surface protective film for solar cells from the gap between adjacent solar cell elements. There was a leak. And in recent years, in a solar cell module provided with a solar cell element capable of performing photoelectric conversion on both front and back surfaces, studies have been made to give solar cell back surface protective film a function of reflecting sunlight and improve power generation efficiency. .
Another object of the present invention is a film that does not have an adhesive layer for adhering to a filler part for embedding a solar cell element on the surface thereof, and a filler part for embedding the solar cell element. Back surface protective film for solar cell comprising a resin layer excellent in adhesiveness, heat resistance, weather resistance and flexibility, and having excellent reflectivity for sunlight, particularly light having a wavelength of 400 to 1,400 nm, and solar cell comprising the same To provide a module.

Moreover, since members, such as a solar cell element in a solar cell module, are easy to see through the filler part containing an ethylene-vinyl acetate copolymer composition etc., it is suppressed and the external appearance property of a solar cell module is improved. For this reason, disposing a dark colored colored layer as a back protective film for solar cells has been studied. However, depending on the constituent material of the dark colored colored layer, sunlight leaked from the gaps between the solar cell elements is absorbed and stored, and the power generation efficiency may be reduced.
Another object of the present invention is a film that does not have an adhesive layer for adhering to a filler part for embedding a solar cell element on the surface thereof, and a filler part for embedding the solar cell element. It has excellent adhesion, heat resistance, weather resistance and flexibility, and has a resin layer excellent in both transparency to light having a wavelength of 800 to 1,400 nm and absorption to light having a wavelength of 400 to 700 nm. It is providing the back surface protective film for solar cells provided with the resin layer excellent in the reflectivity with respect to -1400 nm light, and a solar cell module provided with the same.

The present invention is shown below.
1. A solar cell back surface protective film comprising a first resin layer, a second resin layer, and a third resin layer in order, wherein the first resin layer contains a silicon-containing thermoplastic resin. Protective film.
2. The back surface for solar cells according to 1 above, wherein when light having a wavelength of 400 to 1,400 nm is radiated to the surface of the first resin layer in the back surface protective film for solar cells, the reflectance with respect to the light is 50% or more. Protective film.
3. 3. The solar cell back surface protective film according to 1 or 2, wherein at least one of the first resin layer, the second resin layer, and the third resin layer includes a white colorant.
4). In the first resin layer, the transmittance for light with a wavelength of 800 to 1,400 nm is 60% or more, the absorptance for light with a wavelength of 400 to 700 nm is 60% or more, and the wavelength is 800 to 1,400 nm. 2. The back protective film for solar cells according to 1 above, wherein when light is emitted to the surface of the first resin layer in the back protective film for solar cells, the reflectance with respect to the light is 50% or more.
5). The back protective film for a solar cell according to 1 or 4, wherein the first resin layer includes an infrared transmitting colorant, and the second resin layer and / or the third resin layer includes a white colorant.
6). Furthermore, the back surface protective film for solar cells in any one of said 1 thru | or 5 which equips the outer surface of the said 3rd resin layer with a water vapor | steam barrier layer and / or a back surface protective layer.
7). The back surface for solar cells according to any one of 1 to 6 above, wherein the silicon-containing thermoplastic resin contains a graft polymerization resin obtained by polymerizing a monomer containing an aromatic vinyl compound in the presence of a silicon-containing rubber. Protective film.
8). The thermoplastic resin constituting the first resin layer, the thermoplastic resin constituting the second resin layer, and the thermoplastic resin constituting the third resin layer are derived from an aromatic vinyl compound that is the same or different from each other. The back surface protection film for solar cells in any one of said 1 thru | or 7 containing the structural unit to do.
9. The back surface protective film for solar cells according to any one of 1 to 8 above, wherein the thickness is 30 to 1,000 μm.
10. A solar cell module comprising the solar cell back surface protective film according to any one of 1 to 9 above.

According to the back surface protective film for a solar cell of the present invention, since the first resin layer containing the silicon-containing thermoplastic resin is provided, the first resin layer and the ethylene / vinyl acetate copolymer embedded in the solar cell element. It is excellent in adhesiveness, heat resistance, weather resistance and flexibility with a filler part containing a coalesced composition and the like. Therefore, a solar cell module in which the filler part is reliably protected can be provided.
When light having a wavelength of 400 to 1,400 nm is radiated to the surface of the first resin layer in the back surface protective film for solar cells, the reflectance for the light is 50% or more. Because of the excellent reflectivity for light of most wavelengths of sunlight, when sunlight leaks from the gap between adjacent solar cell elements toward the back surface protective film for solar cells, the reflected light is reflected by the solar cell elements. It can be supplied to the back surface and used for photoelectric conversion to improve power generation efficiency.
Further, when at least one of the first resin layer, the second resin layer, and the third resin layer includes a white colorant, in the resin layer including the white colorant, It has excellent sunlight reflectivity and can supply reflected light to the back surface of the solar cell element and use it for photoelectric conversion to improve power generation efficiency.

In the first resin layer, the transmittance for light with a wavelength of 800 to 1,400 nm is 60% or more, the absorptance for light with a wavelength of 400 to 700 nm is 60% or more, and the wavelength is 800 to 1,400 nm. When light is radiated to the surface of the first resin layer in the solar cell back surface protective film, when the reflectance with respect to this light is 50% or more, sunlight is emitted from the gap between adjacent solar cell elements. When the first resin layer leaks toward the back surface protective film for solar cells, heat storage due to light having a wavelength of 800 to 1,400 nm is suppressed, so heat storage of the filler portion that adheres to the first resin layer Is also suppressed. And the thermal storage in the solar cell module formed using this film is suppressed, and the deformation | transformation of structural members including a film and the fall of electric power generation efficiency can be suppressed.
In addition, when the first resin layer includes an infrared transmitting colorant and the second resin layer and / or the third resin layer includes a white colorant, the first resin layer has a wavelength of 800. A solar cell module having a property of having a transmittance of 60% or more for light of ˜1,400 nm and an absorption factor of 60% or more for light having a wavelength of 400 to 700 nm and having an excellent dark appearance Can be given. And when sunlight hits a film, not only the deformation of the structural members including the film and the decrease in power generation efficiency are suppressed, but also the solar cell provided with the back surface protective film for solar cell of the present invention, When placed on a roof or the like, it has excellent appearance and design.

In the case where the silicon-containing thermoplastic resin contains a graft polymerization resin obtained by polymerizing a monomer containing an aromatic vinyl compound in the presence of a silicon-containing rubber, a solar cell element is formed in the first resin layer. Is excellent in adhesiveness, heat resistance and weather resistance with a filler part containing an ethylene / vinyl acetate copolymer composition and the like.
The thermoplastic resin constituting the first resin layer, the thermoplastic resin constituting the second resin layer, and the thermoplastic resin constituting the third resin layer are derived from an aromatic vinyl compound that is the same or different from each other. When the structural unit is included, the solar cell back surface protective film is excellent in hydrolysis resistance, dimensional stability, impact resistance, and the like.

  According to the solar cell module of the present invention, since the solar cell back surface protective film of the present invention is provided, a solar cell having excellent shape stability and improved photoelectric conversion efficiency can be formed.

It is a schematic sectional drawing which shows an example of the back surface protective film for solar cells of this invention. It is a schematic sectional drawing which shows the other example of the back surface protective film for solar cells of this invention. It is a schematic sectional drawing which shows an example of the solar cell module of this invention.

  The present invention will be described in detail below. In this specification, “(co) polymerization” means homopolymerization and copolymerization. Further, “(meth) acryl” means acryl and methacryl, and “(meth) acrylate” means acrylate and methacrylate.

  The back surface protective film for solar cells of the present invention is a film comprising a first resin layer, a second resin layer, and a third resin layer in order, and the schematic cross section thereof is exemplified in FIGS. 1 and 2. That is, the solar cell back surface protective film 1 </ b> A in FIG. 1 is a laminated film including the first resin layer 11, the second resin layer 12, and the third resin layer 13 in order. The back protective film 1B for a solar cell in FIG. 2 is a laminated film further including other layers 14 and 15 in addition to the first resin layer 11, the second resin layer 12, and the third resin layer 13. And in this invention, the back surface protective film for solar cells is used in order to make it adhere with the exposed surface of the filler part of a solar cell module by the surface of a 1st resin layer.

The first resin layer is a layer containing a thermoplastic resin containing a silicon-containing thermoplastic resin (hereinafter referred to as “thermoplastic resin (I)”), and a thermoplastic resin composition containing this thermoplastic resin (I). It is a layer obtained by using a product (hereinafter referred to as “first thermoplastic resin composition”). And this 1st resin layer is excellent in adhesiveness with the filler part which embeds a solar cell element, and has the effect | action which mainly gives flexibility with respect to the back surface protective film for solar cells of this invention. Is a layer.
The said 2nd resin layer is a base layer in the back surface protection film for solar cells of this invention, is a layer which has an effect | action which mainly gives heat resistance with respect to the back surface protection film for solar cells of this invention, and contains a resin component. Although it will not specifically limit if it is a thing, Preferably it is called the thermoplastic resin composition (henceforth "the thermoplastic resin (II)") (henceforth "the second thermoplastic resin composition"). ).
The said 3rd resin layer is a layer which has an effect | action which mainly gives flexibility with respect to the back surface protection film for solar cells of this invention, and will not be specifically limited if a resin component is included. The third resin layer preferably includes a thermoplastic resin composition (hereinafter referred to as “third thermoplastic resin composition”) including a thermoplastic resin (hereinafter referred to as “thermoplastic resin (III)”). Is a layer obtained using

The back surface protective film for solar cells of the present invention is preferably a film having heat resistance and flexibility, and at least the first thermoplastic resin composition and the third thermoplastic resin composition are preferably film-forming. A composition having In the present invention, the first, second and third thermoplastic resin compositions are particularly preferably compositions having film-forming properties.
In order to impart heat resistance and flexibility to the solar cell back surface protective film of the present invention, the glass transition temperature (hereinafter referred to as “Tg”) of the thermoplastic resin (I) and the thermoplastic resin (hereinafter referred to as “Tg”). The Tg of III) is preferably the same as or lower than the Tg of the thermoplastic resin (II). In order to impart sufficient flexibility, the Tg of the thermoplastic resin (I) and the Tg of the thermoplastic resin (III) are preferably lower than the Tg of the thermoplastic resin (II). The difference between the Tg of the thermoplastic resin (I) and the Tg of the thermoplastic resin (II) is preferably 10 ° C. or higher, more preferably 15 ° C. or higher, and the Tg of the thermoplastic resin (II) and the thermoplastic resin (III ) Is preferably 10 ° C. or higher, more preferably 15 ° C. or higher.
When two or more kinds of thermoplastic resins are contained in one resin layer and a plurality of Tg are detected in a chart obtained by a differential scanning calorimeter (DSC), the highest temperature among the plurality of Tg is adopted as Tg. Shall.

The first resin layer is a layer obtained by using a first thermoplastic resin composition containing a thermoplastic resin (I) containing a silicon-containing thermoplastic resin.
In addition, from the viewpoint of imparting flexibility and heat resistance to the back surface protective film for solar cell of the present invention, the Tg of this thermoplastic resin (I) is preferably 90 ° C to 200 ° C, more preferably 95 ° C to 180 ° C. ° C, more preferably 100 ° C to 160 ° C, particularly preferably 105 ° C to 140 ° C. When the first thermoplastic resin composition includes a plurality of thermoplastic resins, at least one resin has a Tg in the above range. Preferably, at least one silicon-containing thermoplastic resin has a Tg in the above range.

  The thermoplastic resin (I) may be a silicon-containing thermoplastic resin, or may be composed of this silicon-containing thermoplastic resin and a silicon-free thermoplastic resin. The first thermoplastic resin composition may be composed of the thermoplastic resin (I), or may be a composition containing the thermoplastic resin (I) and an additive.

The silicon-containing thermoplastic resin is a resin containing a silicon atom in the molecule, and an aromatic vinyl resin containing a structural unit derived from an aromatic vinyl compound (hereinafter referred to as “silicon-containing aromatic vinyl resin”), Polyolefin resin (silicon-containing polyolefin resin), polyvinyl chloride resin (silicon-containing polyvinyl chloride resin), polyvinylidene chloride resin (silicon-containing polyvinylidene chloride resin), saturated polyester resin (silicon-containing saturated polyester resin), Examples include polycarbonate resin (silicon-containing polycarbonate resin), polyamide resin (silicon-containing polyamide resin), acrylic resin (silicon-containing acrylic resin), fluorine resin (silicon-containing fluorine resin), and silicon resin. These can be used alone or in combination of two or more.
The form of the resin obtained by polymerizing the monomer containing the polymerizable unsaturated compound in the silicon-containing thermoplastic resin is obtained by polymerizing the monomer containing the silicon-containing polymerizable unsaturated compound. A resin comprising a (co) polymer; a graft polymerization resin obtained by polymerizing a monomer containing a silicon-containing polymerizable unsaturated compound in the presence of a silicon-free rubber; a silicon-containing rubber in the presence of a silicon-containing rubber Graft polymerization resin obtained by polymerizing monomer not containing polymerizable unsaturated compound; Graft polymerization obtained by polymerizing monomer containing silicon-containing polymerizable unsaturated compound in the presence of silicon-containing rubber Examples thereof include resins. These resins can be used alone or in combination of two or more.
In the present invention, it is derived from an aromatic vinyl compound because it is excellent in adhesiveness, heat resistance and weather resistance with a filler part containing an ethylene / vinyl acetate copolymer composition or the like embedding a solar cell element. A silicon-containing aromatic vinyl resin having a structural unit is preferred.

  The content of the silicon-containing thermoplastic resin contained in the first thermoplastic resin composition is preferably 1 to 100% by mass, more preferably 3 to 100% by mass with respect to the total amount of the thermoplastic resin (I). %, More preferably 10 to 90% by mass. If it is the above ratio, the first resin layer containing the first thermoplastic resin composition is embedded in the solar cell element, and has adhesiveness with a filler part containing an ethylene / vinyl acetate copolymer composition, Excellent heat resistance and weather resistance.

  On the other hand, as the silicon-free thermoplastic resin, saturated polyester resins such as aromatic vinyl resin, polyolefin resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc. A monomer that does not contain a silicon-containing polymerizable unsaturated compound in the presence of a polycarbonate resin, a polyamide resin, an acrylic resin containing a structural unit derived from a (meth) acrylic acid ester compound, a fluorine resin, or a silicon-free rubber. Examples thereof include a silicon-free graft polymerization resin (diene graft polymerization resin, acrylic graft polymerization resin, etc.) obtained by polymerization. These resins can be used alone or in combination of two or more.

The silicon-containing aromatic vinyl resin is exemplified below.
[1] Silicon-containing copolymer [2] obtained by polymerizing a monomer (hereinafter referred to as “monomer (m11)”) containing an aromatic vinyl compound and a silicon-containing polymerizable unsaturated compound. A graft obtained by polymerizing a monomer (hereinafter referred to as “monomer (m12)”) containing an aromatic vinyl compound and a silicon-containing polymerizable unsaturated compound in the presence of a silicon-free rubber. Polymerized resin (hereinafter referred to as “graft polymerized resin (g11)”)
[3] Graft polymerization resin (hereinafter referred to as “graft polymerization resin”) obtained by polymerizing a monomer containing an aromatic vinyl compound (hereinafter referred to as “monomer (m13)”) in the presence of silicon-containing rubber. (G12) ".)
Of these, the embodiments [2] to [3] are preferable, and the embodiment [3] is particularly preferable.

The silicon-containing copolymer of the above embodiment [1] is a polymer obtained by polymerizing a monomer (m11) containing an aromatic vinyl compound and a silicon-containing polymerizable unsaturated compound.
The aromatic vinyl compound is not particularly limited as long as it is a compound having at least one vinyl bond and at least one aromatic ring. Examples include styrene, α-methyl styrene, o-methyl styrene, p-methyl styrene, β-methyl styrene, ethyl styrene, p-tert-butyl styrene, vinyl toluene, vinyl xylene, vinyl naphthalene, monochlorostyrene, dichloromethane. Examples thereof include styrene, monobromostyrene, dibromostyrene, tribromostyrene, and fluorostyrene. These compounds can be used alone or in combination of two or more. Of these aromatic vinyl compounds, styrene and α-methylstyrene are preferred.

The silicon-containing polymerizable unsaturated compound is not particularly limited as long as it is a compound having a silicon atom and having at least one vinyl bond. For example, a compound represented by the following general formula (1) is used. be able to.
R ¹ Si (OR ² ) ₃ (1)
[Wherein, R ¹ is an organic group having 1 to 20 carbon atoms having at least one carbon-carbon double bond, and R ² is the same as or different from each other, and is a hydrogen atom, an aliphatic hydrocarbon group or an aromatic group. Group hydrocarbon group. ]
Examples of the carbon-carbon double bond include a vinyl group, an acryloyl group, a methacryloyl group, an allyl group, a norbornenyl group, and a cyclohexenyl group.

  Examples of the silicon-containing polymerizable unsaturated compound represented by the general formula (1) include vinyl trialkoxysilane compounds, 3-methacryloxyalkyltrialkoxysilane compounds, 3-acryloxyalkyltrialkoxysilane compounds, and allyltrialkoxysilanes. Compounds, norbornenyl trialkoxysilane compounds, cyclohexenylethyltrialkoxysilane compounds, and the like.

Examples of the vinyl trialkoxysilane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, and vinyltributoxysilane.
Examples of the 3-methacryloxyalkyltrialkoxysilane include 3-methacryloxymethyltrimethoxysilane, 3-methacryloxyethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxymethyltriethoxysilane, 3- Methacryloxyethyltriethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxymethyltripropoxysilane, 3-methacryloxyethyltripropoxysilane, 3-methacryloxypropyltripropoxysilane, 3-methacryloxypropyltributoxy Silane etc. are mentioned.
Examples of the 3-acryloxyalkyltrialkoxysilane include 3-acryloxymethyltrimethoxysilane, 3-acryloxyethyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxymethyltriethoxysilane, 3- Acryloxyethyltriethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxymethyltripropoxysilane, 3-acryloxyethyltripropoxysilane, 3-acryloxypropyltripropoxysilane, 3-acryloxypropyltributoxy Silane etc. are mentioned.
Examples of the allyltrialkoxysilane include allyltrimethoxysilane, allyltriethoxysilane, allyltripropoxysilane, and allyltributoxysilane.
Examples of the norbornenyltrialkoxysilane include norbornenyltrimethoxysilane, norbornenyltriethoxysilane, norbornenyltripropoxysilane, norbornenyltributoxysilane, and the like.
Examples of the cyclohexenylethyltrialkoxysilane include cyclohexenylethyltrimethoxysilane, cyclohexenylethyltriethoxysilane, cyclohexenylethyltripropoxysilane, and cyclohexenylethyltributoxysilane.

  Other silicon-containing polymerizable unsaturated compounds other than the above include diethoxymethylvinylsilane, tris (2-methoxyethoxy) vinylsilane, p-vinylphenylmethyldimethoxysilane, 1- (m-vinylphenyl) methyldimethyliso Propoxysilane, 3- (p-vinylphenoxy) propylmethyldiethoxysilane, 3- (p-vinylbenzoyloxy) propylmethyldimethoxysilane, 2- (p-vinylphenyl) ethylmethyldimethoxysilane, 2- (m- Vinylphenyl) ethylmethyldimethoxysilane, 2- (o-vinylphenyl) ethylmethyldimethoxysilane, 1- (p-vinylphenyl) ethylmethyldimethoxysilane, 1- (m-vinylphenyl) ethylmethyldimethoxysilane, 1- ( o-Vinylphenyl) Eth Methyldimethoxysilane, 1- (o-vinylphenyl) -1,1,2-trimethyl-2,2-dimethoxydisilane, 1- (p-vinylphenyl) -1,1-diphenyl-3-ethyl-3,3 -Diethoxydisiloxane, m-vinylphenyl- [3- (triethoxysilyl) propyl] diphenylsilane, [3- (p-isopropenylbenzoylamino) propyl] phenyldipropoxysilane, N-3- (methacryloxy-2 -Hydroxypropyl) -3-aminopropyltriethoxysilane, methacryloxypropyltris (methoxyethoxy) silane, 3- [tris (trimethylsiloxy) silyl] propyl methacrylate, 3- [tris (dimethylvinylsiloxy)] propyl methacrylate, 3 -(Trichlorosilyl) propylme Acrylate, trimethylsilyl methacrylate, tris (trimethylsiloxy) -3-methacryloxypropylsilane, methacryloxypropylmethyldiethoxysilane, acryloxytrimethylsilane, bistrimethylsilyl itaconate, (methacryloxymethyl) bis (trimethylsiloxy) methylsilane, 2- (Trimethylsiloxy) ethyl methacrylate, 2- (acryloxyethoxy) trimethylsilane, 3-methacryloxypropylbis (trimethylsiloxy) methylsilane, (3-acryloxypropyl) methylbis (trimethylsiloxy) silane, (3-acrylic Roxypropyl) dimethylmethoxysilane, (3-acryloxypropyl) tris (trimethylsiloxy) silane, trichlorovinylsilane, allyltrichlorosilane Orchids.

  The silicon-containing polymerizable unsaturated compounds can be used alone or in combination of two or more.

  The monomer (m11) forming the silicon-containing copolymer of the above embodiment [1] may be composed of an aromatic vinyl compound and a silicon-containing polymerizable unsaturated compound, and the aromatic vinyl compound and Further, it may be composed of a silicon-containing polymerizable unsaturated compound and another vinyl compound. Other vinyl compounds include vinyl cyanide compounds, (meth) acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, amide group-containing unsaturated compounds. Compounds and the like. These can be used alone or in combination of two or more.

Among the other vinyl compounds, examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile, ethacrylonitrile, α-chloro (meth) acrylonitrile and the like. These vinyl cyanide compounds may be used alone or in combination of two or more.
Examples of the (meth) acrylic acid ester compound include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Examples include cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, and the like. These (meth) acrylic acid ester compounds may be used alone or in combination of two or more.

Examples of the maleimide compound include maleimide, N-methylmaleimide, N-butylmaleimide, N-phenylmaleimide, N- (2-methylphenyl) maleimide, N-cyclohexylmaleimide and the like. These maleimide compounds may be used alone or in combination of two or more. In addition, as another method of introducing the structural unit derived from the maleimide compound, for example, a method of copolymerizing maleic anhydride and then imidizing may be used.
Examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, and the like. These unsaturated acid anhydrides may be used alone or in combination of two or more.

  Examples of the hydroxyl group-containing unsaturated compound include 3-hydroxy-1-propene, 4-hydroxy-1-butene, cis-4-hydroxy-2-butene, trans-4-hydroxy-2-butene, and 3-hydroxy- 2-methyl-1-propene, hydroxystyrene, N- (4-hydroxyphenyl) maleimide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate , (Meth) acrylic acid 7-hydroxyheptyl, (meth) acrylic acid - hydroxyoctyl, (meth) acrylic acid 9-hydroxy-nonyl, (meth) acrylate, 12-hydroxylauryl (meth) acrylic acid 11-hydroxy-undecyl, and (meth) 12-hydroxy dodecyl acrylate. These hydroxyl group-containing unsaturated compounds may be used alone or in combination of two or more.

  Examples of the amino group-containing unsaturated compound include aminoethyl (meth) acrylate, propylaminoethyl (meth) acrylate, dimethylaminomethyl (meth) acrylate, diethylaminomethyl (meth) acrylate, (meth) acrylic acid 2 -Dimethylaminoethyl, 2-diethylaminoethyl (meth) acrylate, 2- (di-n-propylamino) ethyl (meth) acrylate, 2-dimethylaminopropyl (meth) acrylate, 2- (meth) acrylic acid 2- Diethylaminopropyl, 2- (di-n-propylamino) propyl (meth) acrylate, 3-dimethylaminopropyl (meth) acrylate, 3-diethylaminopropyl (meth) acrylate, 3- (di) (meth) acrylate -N-propylamino) propyl, (meth) acrylic acid 2-tert- Tylaminoethyl, phenylaminoethyl (meth) acrylate, 4-aminostyrene, 4-dimethylaminostyrene, N-vinyldiethylamine, N-acetylvinylamine, (meth) acrylamine, N-methyl (meth) acrylamine, etc. Is mentioned. These amino group-containing unsaturated compounds can be used alone or in combination of two or more.

  Examples of the amide group-containing unsaturated compound include (meth) acrylamide, N-methylol (meth) acrylamide, 3-dimethylaminopropyl (meth) acrylamide and the like. These amide group-containing unsaturated compounds can be used alone or in combination of two or more.

The content ratio of the structural unit derived from the silicon-containing polymerizable unsaturated compound constituting the silicon-containing copolymer of the above embodiment [1] is preferably 0.01 to 15% by mass with respect to the total amount of the structural unit. More preferably, it is 0.1-10 mass%. If it is the said ratio, the 1st resin layer containing the silicon-containing copolymer of this aspect [1], and the filler part containing an ethylene-vinyl acetate copolymer composition etc. which embeds a solar cell element. Excellent adhesion, heat resistance and weather resistance.
In the silicon-containing copolymer of the above embodiment [1], the content ratio of the structural unit derived from the aromatic vinyl compound and the structural unit derived from the silicon-containing polymerizable unsaturated compound is not particularly limited. The total amount of is preferably 40 to 100% by mass, more preferably 60 to 90% by mass, based on the total amount of the structural units constituting the silicon-containing copolymer. If it is the said ratio, the 1st resin layer containing the silicon-containing copolymer of this aspect [1], and the filler part containing an ethylene-vinyl acetate copolymer composition etc. which embeds a solar cell element. Excellent adhesion, heat resistance and weather resistance.

  The weight average molecular weight (hereinafter also referred to as “Mw”) of the silicon-containing copolymer of the above embodiment [1] is preferably 30,000 from the viewpoint of impact resistance, flexibility, film formability, toughness, and the like. To 1,000,000, more preferably 50,000 to 500,000. The Mw can be measured by GPC using standard polystyrene.

  The silicon-containing copolymer of the above embodiment [1] is produced by polymerizing the monomer in the presence of a polymerization initiator. As the polymerization method, a known method such as solution polymerization is applied.

The graft polymerization resin (g11) of the above embodiment [2] is obtained by polymerizing a monomer (m12) containing an aromatic vinyl compound and a silicon-containing polymerizable unsaturated compound in the presence of a silicon-free rubber. Graft polymerization resin.
The graft polymerization resin (g12) of the above embodiment [3] is a graft polymerization resin obtained by polymerizing the monomer (m13) containing an aromatic vinyl compound in the presence of a silicon-containing rubber.

The components of the non-silicon-containing rubber and silicon-containing rubber used in the above embodiments [2] and [3] are described below, but the physical properties (shape, size, molecular weight, etc.) are not particularly limited. .
The shape of the rubber component is not particularly limited, and may be particulate (spherical or substantially spherical), linear, curved, or the like. When it is in the form of particles, the volume average particle diameter is preferably 5 to 2,000 nm, more preferably 10 to 1,800 nm, and still more preferably 50 to 1,500 nm. When the volume average particle diameter is in the above range, the processability of the first thermoplastic resin composition and the impact resistance of the obtained first resin layer are excellent. The volume average particle diameter can be measured by image analysis using an electron micrograph, a laser diffraction method, a light scattering method, or the like.

  Examples of the non-silicon-containing rubber include acrylic rubbers; homopolymers such as polybutadiene and polyisoprene, styrene / butadiene copolymers, styrene / isoprene copolymers, acrylonitrile / butadiene copolymers, and diene rubbers such as natural rubber. Rubber made of a polymer obtained by hydrogenating a (co) polymer containing a unit comprising a conjugated diene compound; ethylene / α-olefin containing an ethylene unit and a unit comprising an α-olefin having 3 or more carbon atoms Copolymer rubber; urethane rubber and the like. These can be used alone or in combination of two or more.

  The acrylic rubber is preferably a (co) polymer containing a structural unit derived from an alkyl acrylate ester compound having an alkyl group with 2 to 8 carbon atoms. The content of the structural unit is preferably 80% by mass or more, more preferably 90% by mass or more, with respect to the total amount of the structural unit.

  Examples of the alkyl acrylate compound include ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, n-octyl acrylate, and 2-ethylhexyl acrylate. These compounds can be used alone or in combination of two or more. Of these, the alkyl acrylate ester compound is preferably n-butyl acrylate, isobutyl acrylate, and 2-ethylhexyl acrylate.

When the acrylic rubber contains structural units derived from other monomers, the other monomers include vinyl chloride, vinylidene chloride, vinyl cyanide compounds, aromatic vinyl compounds, vinyl ester compounds, methacrylic acid. Alkyl ester compound, carboxyl group-containing unsaturated compound, methoxymethyl (meth) acrylate, ethoxymethyl (meth) acrylate, propoxymethyl (meth) acrylate, butoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) ) Acrylate, propoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, ethoxypropyl (meth) acrylate, propoxypropyl (meth) acrylate, butoxypropyl (meth) acrylate, 2-methoxy- Alkoxy group-containing unsaturation such as methyl-propyl (meth) acrylate, 2-propoxy-1-methylpropyl (meth) acrylate, 2-butoxy-1-methylpropyl (meth) acrylate, methoxytripropylene glycol (meth) acrylate Monofunctional monomers such as compounds, hydroxyl group-containing unsaturated compounds, fluorine-containing unsaturated compounds; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol Di- or triallyl such as mono- or polyethylene glycol di (meth) acrylate such as di (meth) acrylate, divinylbenzene, diallyl phthalate, diallyl maleate, diallyl succinate, triallyl triazine Compounds, allyl (meth) allyl compounds such as acrylates, such as conjugated diene compound, 1,3-butadiene, etc., a polyfunctional monomer or the like having two or more unsaturated bonds. In the present invention, the other monomer preferably contains a polyfunctional monomer. That is, the acrylic rubber is preferably a copolymer containing a structural unit derived from the polyfunctional monomer.
The content of the structural unit derived from the polyfunctional monomer constituting the preferred acrylic rubber is preferably 0.01 to the total amount of the structural unit from the viewpoint of low temperature impact, flexibility, etc. It is 10 mass%, More preferably, it is 0.05-8 mass%, More preferably, it is 0.1-5 mass%.

  Tg of the acrylic rubber is preferably −10 ° C. or less from the viewpoint of low temperature impact property, flexibility and the like.

  Examples of the method for producing the acrylic rubber include emulsion polymerization. In this case, the volume average particle size and the like can be adjusted by selecting production conditions such as the type of emulsifier and the amount used, the type of initiator and the amount used, polymerization time, polymerization temperature, and stirring conditions. . Moreover, as another adjustment method of the said volume average particle diameter (particle diameter distribution), the method of blending 2 or more types of the said acrylic rubber which has a different particle diameter may be sufficient.

  Examples of the silicon-containing rubber include a silicon-containing polymerizable unsaturated compound and at least one selected from conjugated diene compounds such as butadiene, α-olefin compounds such as ethylene and propylene, and alkyl acrylate compounds. Rubber obtained by copolymerization of a monomer (hydrogenated rubber may be used); Silicone rubber made of polyorganosiloxane obtained by polycondensation of one or more organosiloxanes; Organosiloxane and silicon-containing crosslinking Obtained using an agent (saturated silane compound having 3 or 4 alkoxy groups); rubber obtained using an organosiloxane and a silicon-containing polymerizable unsaturated compound; organosiloxane and a silicon-containing crosslink Obtained by using an agent (a saturated silane compound having 3 or 4 alkoxy groups) and a silicon-containing polymerizable unsaturated compound A conjugated diene compound, at least one silicon-free polymerizable unsaturated compound selected from an aromatic vinyl compound, a vinyl cyanide compound, a (meth) acrylic acid ester compound, and the like, and a silicon-containing coupling agent And chlorosilane compounds, alkyltrichlorosilane compounds, dialkylchlorosilane compounds, trichlorosilane, tetrachlorosilane, tetraalkoxysilane compounds, etc.). The silicon-containing rubber can be used singly or in combination of two or more. In addition, when two or more of the silicon-containing rubbers are combined, and when at least one of the silicon-containing rubbers is combined with another rubber, it may be referred to as a composite rubber. In rubber, a plurality of rubbers may be chemically bonded, may have entanglement, or may be a mere coexisting substance.

  The silicon-containing rubber is a rubber obtained by copolymerizing a monomer containing a silicon-containing polymerizable unsaturated compound and an alkyl acrylate ester compound (hereinafter referred to as “silicon-containing rubber (s1)”). A rubber obtained by using an organosiloxane and a silicon-containing polymerizable unsaturated compound (hereinafter referred to as “silicon-containing rubber (s2)”), an organosiloxane, and a silicon-containing crosslinking agent (3 or 4 alkoxy groups). And a rubber obtained using a silicon-containing polymerizable unsaturated compound (hereinafter referred to as “silicon-containing rubber (s3)”) and a composite rubber (hereinafter referred to as “silicon-containing rubber ( s4) ") is preferred.

Of the monomers used for forming the silicon-containing rubber (s1), the silicon-containing polymerizable unsaturated compound may be the compound exemplified in the above embodiment [1]. These compounds can be used alone or in combination of two or more. Of these, the silicon-containing polymerizable unsaturated compounds are p-vinylphenylmethyldimethoxysilane, 2- (p-vinylphenyl) ethylmethyldimethoxysilane, and 3- (p-vinylbenzoyloxy) propylmethyldimethoxysilane. Is preferred, and p-vinylphenylmethyldimethoxysilane is particularly preferred. The content of the silicon-containing polymerizable unsaturated compound contained in 100% by mass of the monomer is preferably 0.01 to 15% by mass, more preferably 0.1 to 10% by mass.
The alkyl acrylate ester compound is preferably an alkyl acrylate ester having 2 to 8 carbon atoms in the alkyl group, and the compounds exemplified in the acrylate alkyl ester compound used for forming the acrylic rubber may be used. it can. These compounds can be used alone or in combination of two or more. Of these, the alkyl acrylate ester compound is preferably n-butyl acrylate, isobutyl acrylate, and 2-ethylhexyl acrylate. The content of the acrylic acid alkyl ester compound contained in 100% by mass of the monomer is preferably 85 to 99.99% by mass, and more preferably 90 to 99.9% by mass.

The monomer used for forming the silicon-containing rubber (s1) may be composed of a silicon-containing polymerizable unsaturated compound and an acrylic acid alkyl ester compound, or a silicon-containing polymerizable unsaturated compound and acrylic. It may consist of an acid alkyl ester compound and another polymerizable compound. Other polymerizable compounds include vinyl cyanide compounds, aromatic vinyl compounds, methacrylic ester compounds, maleimide compounds, unsaturated acid anhydrides, hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, and amide group-containing compounds. Examples thereof include unsaturated compounds, alkoxy group-containing unsaturated compounds, fluorine-containing unsaturated compounds, and polyfunctional monomers having two or more unsaturated bonds. These can be used alone or in combination of two or more.
In this invention, it is preferable that the said monomer contains a polyfunctional monomer, and the compound illustrated in the polyfunctional monomer used for formation of the said acrylic rubber can be used. The amount used is preferably 10% by mass or less, more preferably 5% by mass or less, with respect to 100% by mass of the monomer.

  The Tg of the silicon-containing rubber (s1) is preferably −10 ° C. or less from the viewpoint of low temperature impact property, flexibility, and the like.

The silicon-containing rubber (s2) is a rubber obtained using organosiloxane and a silicon-containing polymerizable unsaturated compound, and is a polyorganosiloxane rubber containing an organosiloxane segment and other segments.
The silicon-containing rubber (s3) is a rubber obtained using organosiloxane, a silicon-containing crosslinking agent (a saturated silane compound having 3 or 4 alkoxy groups) and a silicon-containing polymerizable unsaturated compound. Yes, it is a polyorganosiloxane rubber containing an organosiloxane segment and other segments.
The silicon-containing rubbers (s2) and (s3) are preferably obtained in a latex state by emulsion polymerization, for example, US Pat. Nos. 2,891,920 and 3,294,725. The polyorganosiloxane rubber produced by the method described in the above.

  The polyorganosiloxane rubber is obtained by, for example, shear-mixing organosiloxane and water in the presence of a sulfonic acid-based emulsifier such as alkylbenzene sulfonic acid or alkyl sulfonic acid using a homomixer or an ultrasonic mixer. The silicone rubber contained in the latex obtained by the condensation method is preferable. Alkylbenzenesulfonic acid is suitable because it acts as an emulsifier for organosiloxane and also as a polymerization initiator. In this case, it is preferable to use an alkylbenzene sulfonic acid metal salt, an alkyl sulfonic acid metal salt, or the like in combination because it has an effect of stably maintaining the silicone rubber when the graft polymerization resin is produced. In the present invention, when the organosiloxane is used, a silicon-containing polymerizable unsaturated compound is used in combination, and the polymer terminal may be sealed with a dimethylvinylsilyl group, a methylphenylvinylsilyl group, or the like. Good. Moreover, the terminal of the polyorganosiloxane rubber may be sealed with, for example, a hydroxyl group, an alkoxy group, a trimethylsilyl group, a methyldiphenylsilyl group, or the like.

The organosiloxane used in the above reaction is, for example, a compound having a structural unit represented by the following general formula (2).
_{(R m SiO (4-m} ) / 2) (2)
[Wherein, R represents a substituted or unsubstituted monovalent hydrocarbon group, and m represents an integer of 0 to 3. ]
The structure of the compound represented by the general formula (2) is linear, branched or cyclic, but the compound is preferably an organosiloxane having a cyclic structure. R which this organosiloxane has, that is, monovalent hydrocarbon group includes alkyl group such as methyl group, ethyl group, propyl group and butyl group; aryl group such as phenyl group and tolyl group; vinyl group, allyl group and the like And a group in which some of the hydrogen atoms bonded to carbon atoms in these hydrocarbon groups are substituted with halogen atoms, cyano groups, etc .; and at least one of the hydrogen atoms in the alkyl group is substituted with a mercapto group And the like.

Examples of the organosiloxane include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, and octaphenylcyclotetrasiloxane. In addition to a cyclic compound such as a linear or branched organosiloxane. These can be used alone or in combination of two or more.
The organosiloxane may be a polyorganosiloxane condensed in advance, for example, having an Mw of about 500 to 10,000. When the organosiloxane is a polyorganosiloxane, the molecular chain terminal may be sealed with a hydroxyl group, an alkoxy group, a trimethylsilyl group, a methyldiphenylsilyl group, or the like.

  Moreover, the compound illustrated in said aspect [1] can be used for the silicon-containing polymerizable unsaturated compound used for the said reaction. These compounds can be used alone or in combination of two or more. Among these, silicon-containing polymerizable unsaturated compounds are p-vinylphenylmethyldimethoxysilane, 2- (p-vinylphenyl) ethylmethyldimethoxysilane, and 3- (p-vinylbenzoyloxy) propylmethyldimethoxysilane. Is preferred, and p-vinylphenylmethyldimethoxysilane is particularly preferred.

  In the production of the silicon-containing rubbers (s2) and (s3), when the organosiloxane and the silicon-containing polymerizable unsaturated compound are used in combination, the amount of the silicon-containing polymerizable unsaturated compound used is the sum of these. Preferably it is 0.01-15 mass% with respect to 100 mass% of quantity, More preferably, it is 0.05-12 mass%, More preferably, it is 0.1-10 mass%. If the amount of the silicon-containing polymerizable unsaturated compound used is too large, the resulting first resin layer may not have sufficient impact resistance and weather resistance.

Examples of the silicon-containing crosslinking agent used in the production of the silicon-containing rubber (s3) include trifunctional crosslinking agents such as methyltrimethoxysilane, ethyltrimethoxysilane, phenyltrimethoxysilane, and ethyltriethoxysilane, and tetraethoxysilane. And a tetrafunctional cross-linking agent. A crosslinkable prepolymer obtained by condensation polymerization of these compounds in advance may be used. These may be used alone or in combination of two or more.
The first resin layer containing a graft polymerization resin obtained by polymerizing a monomer (m3) containing an aromatic vinyl compound in the presence of the silicon-containing rubber (s3) obtained using the silicon-containing crosslinking agent Especially excellent in impact resistance.

  The amount of the silicon-containing crosslinking agent used in the production of the silicon-containing rubber (s3) is 100 mass of the total amount of the organosiloxane, the graft crossing agent (usually a silicon-containing polymerizable unsaturated compound) and the silicon-containing crosslinking agent. % Is usually 10% by mass or less, preferably 5% by mass or less, and more preferably 0.01 to 5% by mass. When the usage-amount of the said silicon-containing crosslinking agent exceeds 10 mass%, the softness | flexibility of the polyorganosiloxane type rubber obtained may be impaired, and the flexibility of the 1st resin layer obtained may fall.

The amount of the emulsifier used in the production of the silicon-containing rubber (s2) or (s3) is usually 0.1 to 5 parts by mass with respect to 100 parts by mass of the total amount of the organosiloxane and the silicon-containing polymerizable unsaturated compound. , Preferably it is 0.3-3 mass parts.
The amount of water used in the production of the silicon-containing rubber (s2) or (s3) is usually 100 to 500 parts by mass, preferably 100 parts by mass with respect to the total amount of organosiloxane and silicon-containing polymerizable unsaturated compound. Is 200 to 400 parts by mass.
Moreover, the condensation temperature at the time of manufacture of the said silicon-containing rubber (s2) or (s3) is 5 to 100 degreeC normally.

The volume average particle diameter of the silicon-containing rubbers (s2) and (s3) is usually 500 nm or less, preferably 400 nm or less, more preferably 50 to 400 nm. When the volume average particle diameter is 500 nm or less, the processability of the first thermoplastic resin composition and the impact resistance of the obtained first resin layer are excellent. On the other hand, when the volume average particle diameter exceeds 500 nm, the appearance properties tend to be inferior, for example, the glossiness of the first resin layer is lowered.
The volume average particle size is determined by the amount of emulsifier and water used in the production of the silicon-containing rubbers (s2) and (s3), the method of adding the organosiloxane, the dispersion when using a homomixer or an ultrasonic mixer. It can be easily controlled depending on the degree.

The Tg of the silicon-containing rubber (s2) is preferably −150 ° C. to −30 ° C. from the viewpoint of low temperature impact property, flexibility, and the like.
The Tg of the silicon-containing rubber (s3) is preferably −150 ° C. to −30 ° C. from the viewpoint of low temperature impact property, flexibility, and the like.

The composite rubber (s4) is exemplified below. In these embodiments, as described above, the rubbers may be chemically bonded, may have entanglement, or may be a mere coexisting substance.
(S4-1) Combination of the silicon-containing rubbers (s1) and (s2) (s4-2) Combination of the silicon-containing rubbers (s1) and (s3) (s4-3) Silicone-containing rubber (s1), ( Combination of s2) and (s3) (s4-4) Combination of acrylic rubber and silicon-containing rubber (s2) (s4-5) Combination of acrylic rubber and silicon-containing rubber (s3) (s4-6) Acrylic System rubber, combination of silicon-containing rubbers (s2) and (s3)

  In the composite rubbers of the above aspects (s4-4) to (s4-6), particularly when the rubbers are intertwined, they may be referred to as “silicone / acrylic composite rubbers”. For example, JP-A-4-239010 It can be produced by the method described in 1. Examples of commercially available products in these embodiments include “Metablene SX-006” (trade name) manufactured by Mitsubishi Rayon Co., Ltd.

  The graft polymerization resins (g11) and (g12) according to the above embodiments [2] and [3] are resins generally referred to as rubber-reinforced resins. As a result of the polymerization of monomers around the rubber, the rubber The resin having a graft polymer portion on at least the surface and the inside.

  Examples of the silicon-free rubber used for forming the graft polymerization resin (g11) in the above embodiment [2] include acrylic rubber and diene rubber, and acrylic rubber is preferable.

  As the aromatic vinyl compound and the silicon-containing polymerizable unsaturated compound contained in the monomer (m12) used for forming the graft polymerization resin (g11), the compounds exemplified in the above embodiment [1] can be used. The ratios of the aromatic vinyl compound and the silicon-containing polymerizable unsaturated compound contained in the monomer (m12) are preferably 85 to 99.99% by mass, respectively, when the total of these is 100% by mass. It is 0.01-15 mass%, More preferably, it is 90-99.95 mass% and 0.05-10 mass%.

  The monomer (m12) may be composed of an aromatic vinyl compound and a silicon-containing polymerizable unsaturated compound, an aromatic vinyl compound, a silicon-containing polymerizable unsaturated compound, and another vinyl. It may consist of a system compound. In the latter case, the ratio of the total amount of the aromatic vinyl compound and the silicon-containing polymerizable unsaturated compound contained in the monomer (m12) is usually 60% by mass or more. Other vinyl compounds include vinyl cyanide compounds, (meth) acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, amide group-containing unsaturated compounds. A compound, an epoxy group-containing unsaturated compound, an oxazoline group-containing unsaturated compound, and the like. These can be used alone or in combination of two or more.

The graft polymerization resin (g11) is produced by polymerizing the monomer (m12) in the presence of the silicon-free rubber, but the production method is not particularly limited. , Emulsion polymerization, solution polymerization, bulk polymerization and the like can be applied.
The ratio of the amounts of the silicon-free rubber and the monomer (m12) used in the production of the graft polymerization resin (g11) is 100 parts by weight of the silicon-free rubber and the monomer (m12). ) Is preferably 25 to 400 parts by mass, more preferably 40 to 300 parts by mass.

  In addition, the monomer (m13) used for forming the graft polymerization resin (g12) of the above embodiment [3] may be composed only of an aromatic vinyl compound, or an aromatic vinyl compound and silicon-containing polymerization. It may consist of other vinyl compounds excluding the unsaturated organic compounds. In the latter case, the ratio of the aromatic vinyl compound contained in the monomer (m13) is preferably 20% by mass or more and less than 100% by mass, more preferably 40 to 90% by mass. Other vinyl compounds include vinyl cyanide compounds, (meth) acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, amide group-containing unsaturated compounds. A compound, an epoxy group-containing unsaturated compound, an oxazoline group-containing unsaturated compound, and the like. These can be used alone or in combination of two or more.

The graft polymerization resin (g12) is produced by polymerizing the monomer (m13) in the presence of the silicon-containing rubber, but the production method is not particularly limited. Emulsion polymerization, solution polymerization, bulk polymerization and the like can be applied.
The amount of the silicon-containing rubber and the monomer (m13) used in the production of the graft polymerization resin (g12) is such that the monomer (m13) is used with respect to 100 parts by mass of the silicon-containing rubber. , Preferably it is 25-400 mass parts, More preferably, it is 40-300 mass parts.

  In the present invention, as described above, the silicon-containing aromatic vinyl-based resin may be combined with another thermoplastic resin as the thermoplastic resin (I). Another thermoplastic resin is a resin that contains a silicon atom in the molecule and does not contain a structural unit derived from an aromatic vinyl compound, and a resin that contains no silicon atom in the molecule and contains a structural unit derived from an aromatic vinyl compound And a resin that does not contain a silicon atom in the molecule and does not contain a structural unit derived from an aromatic vinyl compound.

  As a resin that contains a silicon atom in the molecule and does not contain a structural unit derived from an aromatic vinyl compound, a monomer that does not contain an aromatic vinyl compound in the presence of a silicon-containing rubber (hereinafter referred to as “monomer (m14)”. ) ”)), A graft polymer resin (hereinafter referred to as“ graft polymer resin (g13) ”), a silicon-containing acrylic resin, a silicon-containing polyolefin resin, a silicon-containing polyvinyl chloride resin, Examples thereof include silicon-containing polyvinylidene chloride resins, silicon-containing saturated polyester resins, silicon-containing polycarbonate resins, silicon-containing polyamide resins, silicon-containing fluorine resins, and silicon resins.

  As a resin containing a structural unit derived from an aromatic vinyl compound that does not contain a silicon atom in the molecule, a monomer containing an aromatic vinyl compound (hereinafter referred to as “monomer (m15)”) is polymerized. A monomer containing an aromatic vinyl compound (hereinafter referred to as “monomer (m16)”) is polymerized in the presence of the aromatic vinyl (co) polymer obtained and the non-silicon-containing rubber. Examples thereof include a non-silicon-containing graft polymerization resin (hereinafter referred to as “graft polymerization resin (g14)”).

  Examples of the resin that does not contain a silicon atom in the molecule and does not contain a structural unit derived from an aromatic vinyl compound include polyolefin resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene. Saturated polyester resins such as terephthalate and polyethylene naphthalate, polycarbonate resins, polyamide resins, acrylic resins containing structural units derived from (meth) acrylic acid ester compounds, fluororesins, and aromatic vinyl compounds in the presence of silicon-free rubber , A silicon-free graft polymerized resin (hereinafter referred to as “graft polymerized resin (g15)” obtained by polymerizing a monomer containing no silicon-containing polymerizable unsaturated compound (hereinafter referred to as “monomer (m17)”). ) "Etc.). Examples of the graft polymerization resin (g15) include diene graft polymerization resins and acrylic graft polymerization resins.

  When the thermoplastic resin (I) comprises a silicon-containing aromatic vinyl resin and another thermoplastic resin, a combination of a silicon-containing aromatic vinyl resin and a graft polymerization resin (g14), a silicon-containing aromatic vinyl A combination of a base resin and a graft polymerization resin (g15), and the like.

The silicon-containing thermoplastic resin may be a resin other than the silicon-containing aromatic vinyl resin as described above, and specific examples thereof include an aromatic vinyl compound in addition to the graft polymerization resin (g13). Examples thereof include a silicon-containing copolymer obtained by polymerizing a monomer containing a polymerizable unsaturated compound not included and a silicon-containing polymerizable unsaturated compound.
These resins are aromatics obtained by polymerizing the resin components of the above embodiments [1] to [3] and a monomer containing an aromatic vinyl compound (hereinafter referred to as “monomer (m15)”). It can be used in combination with a resin having a structural unit derived from an aromatic vinyl compound, such as a vinyl (co) polymer and the graft polymerization resin (g14). It is excellent in adhesiveness, heat resistance and weather resistance with a filler part containing an ethylene / vinyl acetate copolymer composition and the like embedding a solar cell element.

The thermoplastic resin (I) contained in the first thermoplastic resin composition is an aromatic vinyl (co) polymer obtained by polymerizing the graft polymerization resin (g13) and the monomer (m15), and A case where the resin is a combination of at least one selected from the graft polymerization resin (g14) (hereinafter referred to as “aspect [4]”) will be described.
That is, the above aspect [4] is exemplified below.
(4-1) A resin composed of a graft polymerization resin (g13) and an aromatic vinyl (co) polymer (4-2) A graft polymerization resin (g13) and a silicon-free graft polymerization resin (g14) Resin (4-3) A resin comprising a graft polymerization resin (g13), a silicon-free graft polymerization resin (g14), and an aromatic vinyl (co) polymer

As the silicon-containing rubber used for forming the graft polymerized resin (g13), the silicon-containing rubbers (s1) to (s4) are preferable.
Moreover, as a monomer (m14) used for formation of the said graft polymerization resin (g13), a vinyl cyanide compound, a (meth) acrylic acid ester compound, a maleimide type compound, an unsaturated acid anhydride, hydroxyl group containing unsaturated At least one compound selected from a compound, an amino group-containing unsaturated compound, an amide group-containing unsaturated compound, an epoxy group-containing unsaturated compound, an oxazoline group-containing unsaturated compound, and the like is used.

The graft polymerization resin (g13) is produced by polymerizing the monomer (m14) in the presence of the silicon-containing rubber, but the production method is not particularly limited. Emulsion polymerization, solution polymerization, bulk polymerization and the like can be applied.
The amount of the silicon-containing rubber and the monomer (m14) used in the production of the graft polymerization resin (g13) is such that the monomer (m14) is used with respect to 100 parts by mass of the silicon-containing rubber. , Preferably it is 25-400 mass parts, More preferably, it is 40-300 mass parts.

  The monomer (m15) used for the formation of the aromatic vinyl (co) polymer may be composed only of an aromatic vinyl compound, or an aromatic vinyl compound and a silicon-containing polymerizable unsaturated compound. It may consist of other vinyl compounds. In the latter case, the proportion of the aromatic vinyl compound contained in the monomer (m15) is preferably 20% by mass or more and less than 100% by mass, more preferably 40 to 90% by mass. Other vinyl compounds include vinyl cyanide compounds, (meth) acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, amide group-containing unsaturated compounds. A compound, an epoxy group-containing unsaturated compound, an oxazoline group-containing unsaturated compound, and the like. These can be used alone or in combination of two or more. Of these, vinyl cyanide compounds are preferred.

  The aromatic vinyl (co) polymer is produced by polymerizing the monomer (m15), but the production method is not particularly limited. For example, emulsion polymerization, solution polymerization, bulk Polymerization or the like can be applied.

  Examples of the silicon-free rubber used for forming the silicon-free graft polymerization resin (g14) include acrylic rubber and diene rubber, and acrylic rubber is preferable.

  The monomer (m16) used for forming the silicon-free graft polymerization resin (g14) may be composed of only an aromatic vinyl compound, or an aromatic vinyl compound and a silicon-containing polymerizable unsaturated compound. It may consist of other vinyl compounds. In the latter case, the proportion of the aromatic vinyl compound contained in the monomer (m16) is preferably 20% by mass or more and less than 100% by mass, more preferably 40 to 90% by mass. Other vinyl compounds include vinyl cyanide compounds, (meth) acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, amide group-containing unsaturated compounds. A compound, an epoxy group-containing unsaturated compound, an oxazoline group-containing unsaturated compound, and the like. These can be used alone or in combination of two or more.

The silicon-free graft polymerization resin (g14) is produced by polymerizing the monomer (m16) in the presence of the silicon-free rubber, but its production method is particularly limited. For example, emulsion polymerization, solution polymerization, bulk polymerization, and the like can be applied.
The amount of the silicon-free rubber and the monomer (m16) used in the production of the silicon-free graft polymerization resin (g14) is such that the amount of the monomer is 100 parts by mass of the silicon-free rubber. A body (m16) becomes like this. Preferably it is 25-400 mass parts, More preferably, it is 40-300 mass parts.

  In the above aspect [4], in the case of the above aspect (4-1), the content ratios of the graft polymerization resin (g13) and the aromatic vinyl (co) polymer are not particularly limited, but the graft polymerization resin (g13) The content ratio of the silicon-containing rubber used for formation is preferably 3 to 40% by mass, more preferably 5 to 30% by mass with respect to the entire thermoplastic resin (I). When the content ratio of the silicon-containing rubber is in the above range, the resulting first resin layer is excellent in impact resistance.

  In the above embodiment [4], in the case of the above embodiment (4-2), the content ratio of the graft polymerization resin (g13) and the silicon-free graft polymerization resin (g14) is not particularly limited, but the graft polymerization resin (g13) The ratio of the total content of the silicon-containing rubber used for forming the silicon-free rubber and the silicon-free rubber used for forming the silicon-free graft polymerized resin (g14) is preferably 3 to 3 with respect to the entire thermoplastic resin (I). It is selected to be 40% by mass, more preferably 5 to 30% by mass. When the ratio of the total content of the rubber components is in the above range, the resulting first resin layer is excellent in impact resistance.

  Moreover, in the said aspect [4], when it is the said aspect (4-3), the content rate of graft polymerization resin (g13), silicon-free graft polymerization resin (g14), and aromatic vinyl (co) polymer is as follows. Although not particularly limited, the ratio of the total content of the silicon-containing rubber used for forming the graft polymerization resin (g13) and the silicon-free rubber used for forming the silicon-free graft polymerization resin (g14) is a thermoplastic resin ( I) It is preferably 3 to 40% by mass, more preferably 5 to 30% by mass, based on the whole. When the ratio of the total content of the rubber components is in the above range, the resulting first resin layer is excellent in impact resistance.

The resin component contained in the first thermoplastic resin composition is a graft polymerization resin (g14) and a resin selected from the above embodiments [1] to [3], which is a silicon-containing aromatic vinyl resin. A case where the resins are combined (hereinafter referred to as “aspect [5]”) will be described.
That is, the above aspect [5] is exemplified below.
(5-1) Resin comprising the silicon-free graft polymerization resin (g14) and the silicon-containing copolymer of the above-mentioned embodiment [1] (5-2) Silicon-free graft polymerization resin (g14), and the above-described embodiment [ 2], that is, a resin comprising the graft polymerization resin (g11) (5-3) a silicon-free graft polymerization resin (g14), and the resin of the above embodiment [3], ie, the graft polymerization resin (g12). Resin consisting of

  In the above aspect [5], in the case of the above aspect (5-1), the content ratios of the silicon-free graft polymerization resin (g14) and the silicon-containing copolymer of the above aspect [1] are not particularly limited. The content ratio of the silicon-free rubber used for the formation of the non-containing graft polymerization resin (g14) is preferably 3 to 40% by mass, more preferably 5 to 30% by mass with respect to the entire thermoplastic resin (I). Selected to be. When the content ratio of the non-silicon-containing rubber is within the above range, the resulting first resin layer is excellent in impact resistance.

  In the above aspect [5], in the case of the above aspect (5-2), the content ratio of the silicon-free graft polymerization resin (g14) and the graft polymerization resin (g11) is not particularly limited, but the silicon-free graft polymerization resin The ratio of the total content of the silicon-free rubber used for the formation of (g14) and the silicon-free rubber used for the formation of the graft polymerization resin (g11) is preferably 3 with respect to the entire thermoplastic resin (I). It is selected to be ˜40 mass%, more preferably 5 to 30 mass%. When the content ratio of the non-silicon-containing rubber is within the above range, the resulting first resin layer is excellent in impact resistance.

  In the above aspect [5], in the case of the above aspect (5-3), the content ratio of the silicon-free graft polymerization resin (g14) and the graft polymerization resin (g12) is not particularly limited. The ratio of the total content of the silicon-free rubber used for the formation of (g14) and the silicon-containing rubber used for the formation of the graft polymerization resin (g12) is preferably 3 to 3 with respect to the entire thermoplastic resin (I). It is selected to be 40% by mass, more preferably 5 to 30% by mass. When the content ratio of the non-silicon-containing rubber is within the above range, the resulting first resin layer is excellent in impact resistance.

Furthermore, the resin component contained in the first thermoplastic resin composition polymerizes a monomer (m17) that does not contain an aromatic vinyl compound or a silicon-containing polymerizable unsaturated compound in the presence of a silicon-free rubber. When the resin is a combination of the obtained silicon-free graft polymerization resin (g5) and a resin selected from the above embodiments [1] to [5] which are silicon-containing aromatic vinyl resins (hereinafter referred to as embodiments) [6]) will be described.
That is, the above aspect [6] is exemplified below.
(6-1) Resin comprising the silicon-free graft polymerization resin (g15) and the silicon-containing copolymer of the above-mentioned embodiment [1] (6-2) Silicon-free graft polymerization resin (g15) and the above-mentioned embodiment [ 2], ie, a resin (6-3) containing no silicon-containing graft polymerization resin (g15), and a resin of the above embodiment [3], ie, a graft polymerization resin (g12). A resin (6-4) containing no silicon-containing graft polymerization resin (g15), and a resin (6-5) containing no silicon-containing graft polymerization resin (g15) and the above embodiment [5]. A resin comprising

  Examples of the silicon-free rubber used for forming the silicon-free graft polymerization resin (g15) include acrylic rubber and diene rubber, and acrylic rubber is preferable.

  Examples of the monomer (m17) used for forming the silicon-free graft polymerization resin (g15) include vinyl cyanide compounds, (meth) acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, hydroxyl group-containing compounds. At least one compound selected from a saturated compound, an amino group-containing unsaturated compound, an amide group-containing unsaturated compound, an epoxy group-containing unsaturated compound, an oxazoline group-containing unsaturated compound, and the like is used.

The silicon-free graft polymerization resin (g15) is produced by polymerizing the monomer (m17) in the presence of the silicon-free rubber, but its production method is particularly limited. For example, emulsion polymerization, solution polymerization, bulk polymerization, and the like can be applied.
The ratio of the amounts of the silicon-free rubber and the monomer (m17) used in the production of the silicon-free graft polymerization resin (g15) is 100% by mass with respect to 100 parts by mass of the silicon-free rubber. The body (m17) is preferably 25 to 400 parts by mass, more preferably 40 to 300 parts by mass.

  In the above aspect [6], in the case of the above aspect (6-1), the content ratios of the silicon-free graft polymerization resin (g15) and the silicon-containing copolymer of the above aspect [1] are not particularly limited. The content ratio of the silicon-free rubber used for the formation of the non-containing graft polymerization resin (g15) is preferably 3 to 40% by mass, more preferably 5 to 30% by mass with respect to the entire thermoplastic resin (I). Selected to be. When the content ratio of the non-silicon-containing rubber is within the above range, the resulting first resin layer is excellent in impact resistance.

  In the above aspect [6], in the case of the above aspect (6-2), the content ratio of the silicon-free graft polymerization resin (g15) and the graft polymerization resin (g11) is not particularly limited. The ratio of the total content of the silicon-free rubber used for the formation of (g15) and the silicon-free rubber used for the formation of the graft polymerization resin (g11) is preferably 3 with respect to the entire thermoplastic resin (I). It is selected to be ˜40 mass%, more preferably 5 to 30 mass%. When the ratio of the total content of the silicon-free rubber is within the above range, the resulting first resin layer is excellent in impact resistance.

  In the above aspect [6], in the case of the above aspect (6-3), the content ratio of the silicon-free graft polymerization resin (g15) and the graft polymerization resin (g12) is not particularly limited. The ratio of the total content of the silicon-free rubber used for the formation of (g15) and the silicon-containing rubber used for the formation of the graft polymerization resin (g12) is preferably from 3 to 3 with respect to the entire thermoplastic resin (I). It is selected to be 40% by mass, more preferably 5 to 30% by mass. When the ratio of the total content of the rubber components is in the above range, the resulting first resin layer is excellent in impact resistance.

  In the above embodiment [6], in the case of the above embodiment (6-4), the content ratios of the silicon-free graft polymerization resin (g15) and the resin of the above embodiment [4] are not particularly limited, but silicon-free graft polymerization The ratio of the total content of the rubber components contained in the non-silicon-containing rubber used for forming the resin (g15) and the resin of the above embodiment [4] is preferably 3 to 40 with respect to the entire thermoplastic resin (I). It is selected so as to be 5% by mass, more preferably 5 to 30% by mass. When the ratio of the total content of the rubber components is in the above range, the resulting first resin layer is excellent in impact resistance.

  In the above aspect [6], in the case of the above aspect (6-5), the silicon-free graft polymerization resin (g15) and the resin content of the above aspect [5] are not particularly limited, but silicon-free graft polymerization The ratio of the total content of the rubber components contained in the non-silicon-containing rubber used for forming the resin (g15) and the resin of the above embodiment [5] is preferably 3 to 40 with respect to the entire thermoplastic resin (I). It is selected so as to be 5% by mass, more preferably 5 to 30% by mass. When the ratio of the total content of the rubber components is in the above range, the resulting first resin layer is excellent in impact resistance.

As the method for producing the graft polymerization resins (g11) to (g15), a known method can be applied as described above, and a production method by emulsion polymerization will be described below.
In emulsion polymerization, in addition to rubber components and monomers (meaning monomers (m12), (m13), (m14), (m16) and (m17)), usually polymerization initiators and chain transfer agents. (Molecular weight regulator), emulsifier, water and the like are used.

As the polymerization initiator, a redox in which an organic peroxide such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, or the like and a reducing agent such as a sugar-containing pyrophosphate formulation or a sulfoxylate formulation are combined. System initiators; persulfates such as potassium persulfate; peroxides such as benzoyl peroxide (BPO), lauroyl peroxide, tert-butyl peroxylaurate, and tert-butyl peroxymonocarbonate. These can be used alone or in combination of two or more. Moreover, the usage-amount of the said polymerization initiator is 0.1-1.5 mass% normally with respect to the said monomer whole quantity.
The polymerization initiator can be added to the reaction system all at once or continuously.

Examples of the chain transfer agent include octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-hexyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, tert-tetradecyl mercaptan, and other mercaptans; Examples include α-methylstyrene dimers. These can be used alone or in combination of two or more. The amount of the chain transfer agent used is usually 0.05 to 2.0 mass% with respect to the total amount of the monomers.
The chain transfer agent can be added to the reaction system all at once or continuously.

  Examples of the emulsifier include anionic surfactants and nonionic surfactants. Anionic surfactants include higher alcohol sulfates; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; aliphatic sulfonates such as sodium lauryl sulfate; higher aliphatic carboxylates, aliphatic phosphates, etc. Is mentioned. Examples of nonionic surfactants include polyethylene glycol alkyl ester compounds and alkyl ether compounds. These can be used alone or in combination of two or more. The usage-amount of the said emulsifier is 0.3-5.0 mass% normally with respect to the said monomer whole quantity.

  Emulsion polymerization can be performed under temperature conditions and the like according to the type of monomer, polymerization initiator, and the like. The latex obtained by this emulsion polymerization is usually purified by coagulating with a coagulant to make the resin component powdery, and then washing and drying. Examples of the coagulant include inorganic salts such as calcium chloride, magnesium sulfate, magnesium chloride, and sodium chloride; inorganic acids such as sulfuric acid and hydrochloric acid; organic acids such as acetic acid and lactic acid.

  The graft ratio in the graft polymerization resins (g11) to (g15) is preferably 20% to 170%, more preferably 30% to 170%, and still more preferably 40% to 150%. If the graft ratio is too low, the flexibility of the first resin layer obtained using the first thermoplastic resin composition may not be sufficient. On the other hand, when the graft ratio is too high, the viscosity of the first thermoplastic resin composition becomes high, and it may be difficult to reduce the thickness.

The graft ratio can be determined by the following formula.
Graft ratio (mass%) = {(S−T) / T} × 100
In the above formula, S is obtained by adding 1 gram of the graft polymerization resin to 20 ml of acetone (acetonitrile when the rubber component includes acrylic rubber), shaking at 25 ° C. with a shaker for 2 hours, The mass (gram) of insoluble matter obtained by centrifuging at 60 ° C. for 60 minutes with a centrifuge (rotation speed: 23,000 rpm) to separate the insoluble matter and the soluble matter, and T is 1 gram It is the mass (gram) of the rubber component contained in the graft polymerization resin. The mass of the rubber component can be obtained by a method of calculating from a polymerization prescription and a polymerization conversion rate, a method of obtaining from an infrared absorption spectrum (IR), and the like.

  The graft ratio is determined by appropriately determining, for example, the type and amount of polymerization initiator used in the production of the graft polymerization resin, the type and amount of chain transfer agent, the monomer addition method and addition time, the polymerization temperature, etc. , Can be adjusted by selecting.

  The intrinsic viscosity [η] (in methyl ethyl ketone, 30 ° C.) of the acetone-soluble component of the graft polymerization resin (when the rubber component includes acrylic rubber, acetonitrile-soluble component) is preferably 0.1 to 2.5 dl / g, more preferably 0.2 to 1.5 dl / g, still more preferably 0.25 to 1.2 dl / g. When the intrinsic viscosity is within this range, it is possible to form a first resin layer that is excellent in processability of the first thermoplastic resin composition and has high thickness accuracy.

Here, the intrinsic viscosity [η] can be obtained in the following manner.
When determining the graft ratio in the graft polymerized resin, acetone-soluble components recovered after centrifugation (if the rubber component contains acrylic rubber, acetonitrile-soluble components) are dissolved in methyl ethyl ketone, and those having different concentrations are obtained. The intrinsic viscosity [η] is determined by preparing a point and measuring the reduced viscosity of each concentration at 30 ° C. using an Ubbelohde viscosity tube.

  The intrinsic viscosity [η] is used when producing the graft polymerization resin, by adjusting the type and amount of polymerization initiator, chain transfer agent, emulsifier, solvent, etc., and further adjusting the polymerization time, polymerization temperature, etc. It can be controlled easily.

  In order to particularly improve the adhesion between the first resin layer and a filler part containing an ethylene / vinyl acetate copolymer composition, which embeds the solar cell element, the silicon-containing thermoplastic resin is used. The content of the silicon-containing structural unit derived from is preferably 0.05 to 20% by mass with respect to the total amount of the structural unit constituting the thermoplastic resin (I) contained in the first thermoplastic resin composition, More preferably, it is 0.07-15 mass%, More preferably, it is 0.1-10 mass%. When there is too much content of the said silicon-containing structural unit, an external appearance property may fall. The silicon-containing structural unit means a unit derived from a silicon-containing polymerizable unsaturated compound and a unit derived from an organosiloxane.

In order to make the first resin layer particularly excellent in heat resistance, the thermoplastic resin (I) contained in the first thermoplastic resin composition is a structural unit derived from a maleimide compound (hereinafter referred to as “structure”). Unit (u11) ”). This structural unit (u11) may be derived from any resin component. That is, the silicon-containing thermoplastic resin may contain the structural unit (u11), and other thermoplastic resins may contain the structural unit (u11).
From the above viewpoint, the content of the structural unit (u11) is preferably 1 to 45% by mass with respect to the total amount of the structural units constituting the thermoplastic resin (I) contained in the first thermoplastic resin composition. More preferably, it is 5-40 mass%, More preferably, it is 10-35 mass%. When there is too much content of the said structural unit (u11), the flexibility of a 1st resin layer may fall.

  The resin component having the structural unit (u11) is preferably a copolymer comprising a structural unit derived from an aromatic vinyl compound, a structural unit derived from a vinyl cyanide compound, and a structural unit (u11). . The content ratio of each structural unit is not particularly limited. Examples of the copolymer include acrylonitrile / styrene / N-phenylmaleimide copolymer.

Furthermore, in order to make the first resin layer particularly excellent in hydrolysis resistance, the thermoplastic resin (I) contained in the first thermoplastic resin composition is a structural unit derived from an aromatic vinyl compound. (Hereinafter referred to as “structural unit (t11)”). As described above, since the silicon-containing thermoplastic resin preferably contains a silicon-containing aromatic vinyl resin, the content of the structural unit (t11) may be satisfied only by this resin, or the silicon-containing thermoplastic resin. It may be filled with an aromatic vinyl resin and another aromatic vinyl resin.
From the above viewpoint, the content of the structural unit (t11) is preferably 30 to 80% by mass with respect to the total amount of the structural units constituting the thermoplastic resin (I) contained in the first thermoplastic resin composition. More preferably, it is 35-75 mass%, More preferably, it is 40-70 mass%. When there is too much content of the said structural unit (t11), heat resistance, flexibility, etc. may be inferior.

  Additives blended in the first thermoplastic resin composition used to form the first resin layer include antioxidants, ultraviolet absorbers, anti-aging agents, colorants, fluorescent whitening agents, weathering agents, and fillers. , Antistatic agents, flame retardants, antifogging agents, antibacterial agents, fungicides, antifouling agents, tackifiers and the like. Specific compounds and their blending amounts in these additives will be described later together with preferred embodiments of the solar cell back surface protective film of the present invention.

The first resin layer is a layer obtained by using a first thermoplastic resin composition obtained by melt-kneading a first raw material composition containing a thermoplastic resin (I) containing a silicon-containing thermoplastic resin.
The melt kneading method and apparatus for the first raw material composition are not particularly limited. For example, the first raw material composition is melt kneaded under known conditions using a single screw extruder, a twin screw extruder, a Banbury mixer, a kneader, a continuous kneader, or the like. A first thermoplastic resin composition is produced.
The thickness of the first resin layer is usually 5 to 500 μm, preferably 10 to 400 μm.

  As described above, the second resin layer is a base layer in the solar cell back surface protective film of the present invention, and is a layer obtained using the second thermoplastic resin composition containing the thermoplastic resin (II). is there.

  The glass transition temperature (Tg) of the thermoplastic resin (II) is the third resin layer or its back surface from the viewpoint of imparting sufficient flexibility and heat resistance to the back surface protective film for solar cell of the present invention. When printing, surface treatment, or the like is performed on the layer disposed on the side as necessary, from the viewpoint of suppressing thermal shrinkage associated with the temperature history and the like, it is preferably 110 ° C to 220 ° C, more preferably 115 ° C to 200 ° C. ° C, more preferably 120 ° C to 190 ° C, particularly preferably 125 ° C to 180 ° C.

  The thermoplastic resin (II) is not particularly limited as long as it is a thermoplastic resin, and may be a silicon-free thermoplastic resin or a silicon-containing thermoplastic resin containing a silicon atom in the molecule. Also good. Moreover, you may use combining these.

Examples of the silicon-free thermoplastic resin include aromatic vinyl resin, polyolefin resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, saturated polyester resin, polycarbonate resin, acrylic resin, fluororesin, ethylene / vinyl acetate. Examples thereof include resins. These can be used alone or in combination of two or more.
The silicon-containing thermoplastic resin includes aromatic vinyl resin (silicon-containing aromatic vinyl resin), polyolefin resin (silicon-containing polyolefin resin), polyvinyl chloride resin (silicon-containing polyvinyl chloride resin), poly Vinylidene chloride resin (silicon-containing polyvinylidene chloride resin), saturated polyester resin (silicon-containing saturated polyester resin), polycarbonate resin (silicon-containing polycarbonate resin), polyamide resin (silicon-containing polyamide resin), acrylic resin (silicon-containing) Acrylic resin), fluororesin (silicon-containing fluororesin), silicon resin and the like. About these silicon-containing thermoplastic resins, the silicon-containing thermoplastic resin contained in the said 1st thermoplastic resin composition can be applied, and it can be used individually by 1 type or in combination of 2 or more types.
When the thermoplastic resin (II) contains a silicon-containing thermoplastic resin, the silicon-containing thermoplastic resin may be the same as or different from the silicon-containing thermoplastic resin contained in the thermoplastic resin (I). May be.

  The thermoplastic resin (II) includes an aromatic vinyl resin containing a structural unit derived from an aromatic vinyl compound (hereinafter referred to as “aromatic vinyl resin (II-1)” from the viewpoints of hydrolysis resistance, dimensional stability, and the like. ) ") Is preferred. The aromatic vinyl resin (II-1) may be a silicon-free thermoplastic resin or a silicon-containing thermoplastic resin (silicon-containing aromatic vinyl resin or the like) containing a silicon atom in the molecule. May be.

  As said aromatic vinyl resin (II-1), the graft | grafting obtained by superposing | polymerizing the monomer (henceforth "monomer (m21)") containing an aromatic vinyl compound in presence of rubber | gum. Polymerized resin (hereinafter referred to as “graft polymerized resin (g21)”); an aromatic vinyl-based polymer obtained by polymerizing a monomer (hereinafter referred to as “monomer (m22)”) containing an aromatic vinyl compound. Co) polymer (hereinafter referred to as “(co) polymer (c21)”); and a mixture of the graft polymerization resin (g21) and (co) polymer (c21) (hereinafter referred to as “mixture (y21)”). Said).

  When the aromatic vinyl resin (II-1) is a graft polymerization resin (g21), the rubber used for the formation of the graft polymerization resin (g21) may be acrylic rubber; polybutadiene, polyisoprene, styrene / butadiene Diene rubber made of polymer, styrene / isoprene copolymer, acrylonitrile / butadiene copolymer, natural rubber, etc .; made of hydrogenated (co) polymer containing unit consisting of conjugated diene compound Hydrogenated rubber; ethylene / α-olefin copolymer rubber containing an ethylene unit and a unit comprising an α-olefin having 3 or more carbon atoms; urethane rubber; silicone rubber; silicone / acrylic composite rubber. These can be used alone or in combination of two or more.

  The shape of the rubber is not particularly limited. When this shape is particulate, the volume average particle diameter is preferably 5 to 2,000 nm, more preferably 10 to 1,800 nm, and still more preferably 50 to 1,500 nm. When the volume average particle diameter is in the above range, the processability of the second thermoplastic resin composition, the impact resistance of the obtained second resin layer, and the like are excellent.

The rubber used for the formation of the graft polymerization resin (g21) may be the same as the rubber component used for the formation of the graft polymerization resins (g11) to (g15) that can be contained in the first resin layer. May be different.
In the present invention, the rubber is preferably a diene rubber from the viewpoint of impact resistance, and from the viewpoint of weather resistance, an acrylic rubber, a silicone rubber, a silicone / acrylic composite rubber, an ethylene / α-olefin copolymer. Rubber and hydrogenated rubber are preferred.

  Therefore, the second thermoplastic resin containing the graft polymerization resin (g21) obtained by using the diene rubber or the mixture (y21) containing the graft polymerization resin (g21) and the (co) polymer (c21). The resin composition can form a second resin layer that is excellent in flexibility and impact resistance.

  The diene rubber is preferably a (co) polymer having a glass transition point of −20 ° C. or less from the viewpoints of flexibility, low temperature impact property and the like.

  The acrylic rubber is preferably a copolymer having two or more glass transition temperatures since it can impart sufficient flexibility to the film.

  As the acrylic rubber, the acrylic rubber described as the silicon-free rubber used for forming the silicon-containing aromatic vinyl resin blended in the first thermoplastic resin composition used for forming the first resin layer. Is preferred. The acrylic rubber is preferably a (co) polymer having a glass transition point of −10 ° C. or less from the viewpoint of flexibility, low temperature impact property and the like.

The acrylic rubber is preferably methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, ethoxyethoxyethyl acrylate, methoxytripropylene glycol acrylate , 4-hydroxybutyl acrylate, lauryl methacrylate, stearyl methacrylate, and other rubbers obtained by (co) polymerizing monomers containing (meth) acrylic acid alkyl ester compounds. These (meth) acrylic acid alkyl ester compounds can be used alone or in combination of two or more.
In addition to the (meth) acrylic acid alkyl ester compound, the monomer includes an aromatic vinyl compound such as styrene, α-methylstyrene, and vinyl toluene; a vinyl cyanide compound such as acrylonitrile and methacrylonitrile; a methacryloyl group. A monofunctional monomer such as silicone having fluorine, a fluorine-containing unsaturated compound, or a polyfunctional monomer such as allyl (meth) acrylate may be included as a copolymerization component in a total amount of 30% by mass or less. .

  The structural unit constituting the acrylic rubber is preferably a structural unit derived from an acrylic acid alkyl ester compound such as n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, and allyl (meth) acrylate. It is a structural unit derived from the polyfunctional monomer. The content of the structural unit derived from the polyfunctional monomer constituting the preferable acrylic rubber is preferably 0.01 to the total amount of the structural unit from the viewpoint of flexibility, low temperature impact property, and the like. It is 10 mass%, More preferably, it is 0.05-8 mass%, More preferably, it is 0.1-5 mass%.

  The volume average particle diameter of the acrylic rubber is preferably 5 to 500 nm, more preferably 10 to 450 nm, and still more preferably 30 to 400 nm, from the viewpoints of flexibility, low temperature impact properties, and the like.

  Examples of the silicone rubber include silicon-containing rubbers exemplified as silicon-containing rubbers used for forming silicon-containing aromatic vinyl-based resins blended in the first thermoplastic resin composition used for forming the first resin layer ( s2) and silicon-containing rubber (s3) are preferred. That is, a polyorganosiloxane rubber obtained by using an organosiloxane and a silicon-containing polymerizable unsaturated compound, and containing an organosiloxane segment and another segment, as well as an organosiloxane and a silicon-containing crosslinking agent (3 or 4), a polyorganosiloxane rubber obtained by using a silicon-containing polymerizable unsaturated compound and an organosiloxane segment and other segments. Preferred configurations of these silicone rubbers are also as described in the silicon-containing rubber (s2) and the silicon-containing rubber (s3). Further, these silicone rubbers are preferably rubbers contained in latex in order to facilitate emulsion polymerization, which is a suitable method for producing a graft polymerization resin. Therefore, this silicone rubber is prepared as described above by, for example, a polyorganosiloxane produced by the method described in US Pat. Nos. 2,891,920 and 3,294,725. It can be a rubber.

  The volume average particle diameter of the silicone rubber is preferably 5 to 500 nm, more preferably 10 to 450 nm, and still more preferably 30 to 400 nm from the viewpoints of flexibility, low temperature impact property and the like.

  In addition, as the silicone / acrylic composite rubber, a composite rubber (s4-4) used for forming a silicon-containing aromatic vinyl resin to be blended with the first thermoplastic resin composition used for forming the first resin layer. ) To (s4-6) are preferable. Particularly preferred is a composite rubber having a structure in which the polyorganosiloxane rubber and the acrylic rubber are intertwined so that they cannot be separated.

As the polyorganosiloxane rubber, a copolymer obtained by copolymerizing an organosiloxane can be preferably used. Examples of the organosiloxane include various reduced products having three or more members, such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, Tetramethyltetraphenylcyclotetrasiloxane and octaphenylcyclotetrasiloxane are preferred. These organosiloxanes can be used alone or in combination of two or more.
The content of the structural unit derived from the organosiloxane constituting the polyorganosiloxane rubber is preferably 50% by mass or more, more preferably 70% by mass or more based on the total amount of the structural unit.

  The volume average particle diameter of the silicone / acrylic composite rubber is preferably 5 to 500 nm, more preferably 10 to 450 nm, and still more preferably 30 to 400 nm, from the viewpoint of flexibility, low temperature impact property and the like.

The ethylene / α-olefin copolymer rubber is a copolymer containing an ethylene unit and a unit composed of an α-olefin having 3 or more carbon atoms, and includes an ethylene / α-olefin copolymer, Examples include olefin / non-conjugated diene copolymers.
Examples of the ethylene / α-olefin copolymer include an ethylene / propylene copolymer and an ethylene / butene-1 copolymer. Examples of the ethylene / α-olefin / non-conjugated diene copolymer include an ethylene / propylene / non-conjugated diene copolymer and an ethylene / butene-1 / non-conjugated diene copolymer.

  The α-olefin is preferably an α-olefin having 3 to 20 carbon atoms, specifically, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1 -Heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 1-eicocene and the like. In the α-olefin, a more preferable carbon number is 3 to 12, and further preferably 3 to 8.

  The proportion of ethylene units and α-olefin units constituting the ethylene / α-olefin copolymer rubber is preferably 5 to 95% by mass and 5 to 95%, respectively, when the total of these is 100% by mass. More preferably, they are 50-90 mass% and 10-50 mass%, More preferably, they are 60-88 mass% and 12-40 mass%, Most preferably, they are 70-85 mass% and 15-30 mass%. When there is too much content rate of the said alpha olefin unit, flexibility may fall.

When the ethylene / α-olefin copolymer rubber is an ethylene / α-olefin / non-conjugated diene copolymer, examples of the non-conjugated diene include alkenyl norbornene such as 5-ethylidene-2-norbornene; dicyclopentadiene Cyclic dienes such as aliphatic diene and the like. These compounds can be used alone or in combination of two or more.
The content of the structural unit derived from the non-conjugated diene is preferably 1 to 30% by mass, more preferably 2 with respect to the total amount of the structural unit constituting the ethylene / α-olefin / non-conjugated diene copolymer. ˜20 mass%. When there is too much content rate of a nonconjugated diene unit, a shaping | molding external appearance property and weather resistance may fall.

The amount of unsaturated groups in the ethylene / α-olefin copolymer rubber is preferably 4 to 40 in terms of iodine value.
The Mooney viscosity (ML _{1 + 4} , 100 ° C .; conforming to JIS K6300) of the ethylene / α-olefin copolymer rubber is preferably 5 to 80, more preferably 10 to 65, and still more preferably 15 to 45. is there. When the Mooney viscosity is in the above range, the impact resistance and flexibility are excellent.

The hydrogenated rubber is not particularly limited as long as it is a (co) polymer obtained by hydrogenating a (co) polymer containing a structural unit derived from a conjugated diene compound.
Examples of the hydrogenated rubber include hydrogenated products of conjugated diene block copolymers having the following structure. That is, a polymer block A composed of a structural unit derived from an aromatic vinyl compound; a double bond portion of a polymer composed of a structural unit derived from a conjugated diene compound having a 1,2-vinyl bond content exceeding 25 mol%. Polymer block B formed by hydrogenation of 95 mol% or more; 95 mol% or more of a double bond portion of a polymer composed of a structural unit derived from a conjugated diene compound having a 1,2-vinyl bond content of 25 mol% or less Hydrogenated polymer block C formed by hydrogenation; and 95 mol% or more of a double bond portion of a copolymer composed of a structural unit derived from an aromatic vinyl compound and a structural unit derived from a conjugated diene compound. It is a block copolymer which consists of what combined 2 or more types among the polymer blocks D formed.

The molecular structure of the block copolymer may be branched, radial, or a combination thereof. The block structure may be a diblock, triblock, multiblock, or a combination thereof.
As a structure of the said block copolymer, A- (BA) _n , (AB) _n , A- (BC) _n , C- (BC) _n , (BC) _n , A- (DA) _n , (AD) _n , A- (DC) _n , C- (DC) _n , (D-C) _n , A- (BCD) ) _N , (A-B-C-D) _n [n is an integer of 1 or more. Etc., preferably AB-A, A-B-A-B, A-B-C, A-D-C and C-B-C.

The aromatic vinyl compound used for forming the polymer blocks A and D constituting the block copolymer is not particularly limited as long as it is a compound having at least one vinyl bond and at least one aromatic ring. . Examples thereof include styrene, α-methylstyrene, methylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, fluorostyrene, p-tert-butylstyrene, ethylstyrene, vinylnaphthalene, and the like. . These compounds can be used alone or in combination of two or more. Of these, styrene is preferred.
The content ratio of the polymer block A constituting the block copolymer is preferably 0 to 65% by mass, more preferably 10 to 40% by mass with respect to the whole polymer. When there is too much content of the polymer block A, impact resistance may not be enough.

  The polymer blocks B, C and D are formed by hydrogenating a pre-hydrogenation block copolymer obtained using a conjugated diene compound and an aromatic vinyl compound. Examples of the conjugated diene compound used for forming the polymer blocks B, C, and D include 1,3-butadiene, isoprene, 1,3-pentadiene, chloroprene, and the like. These compounds can be used alone or in combination of two or more. Of these, 1,3-butadiene and isoprene are preferred because they can be utilized industrially and have excellent physical properties.

The hydrogenation rates of the polymer blocks B, C and D are all 95 mol% or more, preferably 96 mol% or more.
The 1,2-vinyl bond content in the polymer block B is preferably more than 25 mol% and 90 mol% or less, more preferably 30 to 80 mol%. If the 1,2-vinyl bond content is 25 mol% or less, the rubbery properties are lost and the impact resistance may not be sufficient. On the other hand, when it exceeds 90 mol%, chemical resistance may not be sufficient.
The 1,2-vinyl bond content in the polymer block C is preferably 25% mol or less, more preferably 20 mol% or less.

The 1,2-vinyl bond content in the polymer block D is preferably 25 to 90 mol%, more preferably 30 to 80 mol%. If the 1,2-vinyl bond content is less than 25 mol%, the rubbery properties are lost and the impact resistance may not be sufficient. On the other hand, when it exceeds 90 mol%, chemical resistance may not be sufficient.
The amount of the aromatic vinyl compound unit in the polymer block D is preferably 25% by mass or less, more preferably 20% by mass or less. If the amount of the aromatic vinyl compound unit exceeds 25% by mass, rubber properties may be lost and impact resistance may not be sufficient.

  Examples of the hydrogenated rubber include hydrogenated polybutadiene, hydrogenated styrene / butadiene rubber, styrene / ethylene butylene / olefin crystal block polymer, olefin crystal / ethylene butylene / olefin crystal block polymer, styrene / ethylene butylene / styrene block polymer, butadiene / Examples include hydrogenated acrylonitrile copolymers.

  The hydrogenated rubber has a weight average molecular weight (Mw) of preferably 10,000 to 1,000,000, more preferably 30,000 to 800,000, and still more preferably 50,000 to 500,000. When Mw is in the above range, the flexibility is excellent.

The monomer (m21) used for the formation of the graft polymerization resin (g21) contains an aromatic vinyl compound, and the content thereof is usually 30 to 100 with respect to the whole of the monomer (m21). The mass is more preferably 40 to 95 mass%, still more preferably 50 to 90 mass%. As the aromatic vinyl compound, the compounds exemplified in the aromatic vinyl compound used for forming the silicon-containing aromatic vinyl resin to be blended in the first thermoplastic resin composition used for forming the first resin layer are used. be able to. As the aromatic vinyl compound, styrene and α-methylstyrene are preferable.
In addition to the aromatic vinyl compound, the monomer (m21) includes a vinyl cyanide compound, a (meth) acrylic acid ester compound, a maleimide compound, an unsaturated acid anhydride, a hydroxyl group-containing unsaturated compound, and an amino group-containing unsaturated compound. A saturated compound, an amide group-containing unsaturated compound, an epoxy group-containing unsaturated compound, an oxazoline group-containing unsaturated compound, or the like can be used. These other compounds can be used singly or in combination of two or more. Of the above, vinyl cyanide compounds are preferred, and acrylonitrile is preferred.

  In the monomer (m21), the total amount of the aromatic vinyl compound and the vinyl cyanide compound used is the monomer (m21) from the viewpoint of molding processability, chemical resistance, hydrolysis resistance, molding appearance and the like. ) Preferably it is 70-100 mass% with respect to the whole quantity, More preferably, it is 80-100 mass%. In addition, the use ratio of the aromatic vinyl compound and the vinyl cyanide compound is, from the viewpoint of molding processability, chemical resistance, hydrolysis resistance, molding appearance, etc. Preferably they are 5-95 mass% and 5-95 mass%, More preferably, they are 50-95 mass% and 5-50 mass%, More preferably, they are 60-90 mass% and 10-40 mass%.

  Moreover, the said monomer (m21) can provide the outstanding heat resistance to a 2nd resin layer by including a maleimide type compound. In addition, preferable content of the structural unit derived from the maleimide-type compound contained in the said graft polymerization resin (g21) or the said mixture (y21) is mentioned later.

As the graft polymerization resin (g21), preferred resins are as follows.
(G21-1) Graft polymerization resin obtained by polymerizing a monomer comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of rubber (g21-2) In the presence of rubber, an aromatic vinyl compound In the presence of a graft polymerization resin (g21-3) rubber obtained by polymerizing a monomer comprising a vinyl cyanide compound and a maleimide compound, an aromatic vinyl compound, a vinyl cyanide compound and a methacrylic ester compound are used. Graft polymerization resin obtained by polymerizing the monomer

  The method for producing the graft polymerization resin (g21) is exemplified by the graft polymerization resin (g11) exemplified as the silicon-containing aromatic vinyl resin blended in the first thermoplastic resin composition used for forming the first resin layer. To (g15).

  The graft ratio of the graft polymerization resin (g21) is preferably 20 to 170%, more preferably 30 to 170%, still more preferably 40 to 150%. When this graft ratio is too low, the flexibility as a film may not be sufficient. On the other hand, if the graft ratio is too high, the viscosity of the second thermoplastic resin composition becomes high, and it may be difficult to reduce the thickness.

  The said graft polymerization resin (g21) can be used individually by 1 type or in combination of 2 or more types.

When the aromatic vinyl resin (II-1) is the (co) polymer (c21), the monomer (m22) forming the (co) polymer (c21) contains an aromatic vinyl compound. If it is a thing, it will not specifically limit.
The monomer (m22) contains an aromatic vinyl compound, and the content thereof is usually 30 to 100% by mass, more preferably 40 to 95% by mass, based on the whole monomer (m22). More preferably, it is 50-90 mass%. As the aromatic vinyl compound, the compounds exemplified above can be used. As the aromatic vinyl compound, styrene and α-methylstyrene are preferable.
In addition to the aromatic vinyl compound, the monomer (m22) includes a vinyl cyanide compound, a (meth) acrylic acid ester compound, a maleimide compound, an unsaturated acid anhydride, a hydroxyl group-containing unsaturated compound, and an amino group-containing non-volatile compound. A saturated compound, an amide group-containing unsaturated compound, an epoxy group-containing unsaturated compound, an oxazoline group-containing unsaturated compound, or the like can be used. These other compounds can be used singly or in combination of two or more. Of the above, vinyl cyanide compounds are preferred, and acrylonitrile is preferred.

  In the monomer (m22), the total amount of the aromatic vinyl compound and the vinyl cyanide compound used is the monomer (m22) from the viewpoint of molding processability, chemical resistance, hydrolysis resistance, molding appearance, and the like. ) Preferably it is 40-100 mass% with respect to the whole quantity, More preferably, it is 50-100 mass%. In addition, the use ratio of the aromatic vinyl compound and the vinyl cyanide compound is, from the viewpoint of molding processability, chemical resistance, hydrolysis resistance, molding appearance, etc. Preferably they are 5-95 mass% and 5-95 mass%, More preferably, they are 40-95 mass% and 5-60 mass%, More preferably, they are 50-90 mass% and 10-50 mass%.

  Moreover, the said monomer (m22) can provide the outstanding heat resistance to a 2nd resin layer by including a maleimide type compound.

When the (co) polymer (c21) is a copolymer, preferred polymers are as follows.
(C21-1) a copolymer comprising a structural unit derived from an aromatic vinyl compound and a structural unit derived from a vinyl cyanide compound (c21-2) a structural unit derived from an aromatic vinyl compound, and vinyl cyanide A copolymer comprising a structural unit derived from a compound and a structural unit derived from a maleimide compound

  The production method of the (co) polymer (c21) is not particularly limited, and for example, emulsion polymerization, solution polymerization, bulk polymerization and the like can be applied.

  The said (co) polymer (c21) can be used individually by 1 type or in combination of 2 or more types.

  When the aromatic vinyl resin (II-1) is the mixture (y21), the content ratio of the graft polymerization resin (g21) and the (co) polymer (c21) is not particularly limited. Moreover, in the case where the aromatic vinyl resin (II-1) is the graft polymerization resin (g21) and the mixture (y21), the second thermoplastic resin composition is included in the second thermoplastic resin composition. The ratio of the total content of the rubber contained is preferably 3 to 40% by mass, more preferably 5 to 30% by mass with respect to the entire thermoplastic resin (II) from the viewpoint of impact resistance.

  In both cases where the aromatic vinyl resin (II-1) is made of the graft polymerization resin (g21) and the mixture (y21), the aromatic vinyl resin (II-1) The intrinsic viscosity [η] (measured in methyl ethyl ketone at 30 ° C.) of the component soluble in acetone (however, when the rubber is an acrylic rubber, acetonitrile) is preferably 0.1 to 2.5 dl / g. More preferably, it is 0.2-1.5 dl / g, More preferably, it is 0.25-1.2 dl / g. When the intrinsic viscosity [η] is within the above range, the processability of the second thermoplastic resin composition is excellent, and the thickness accuracy of the second resin layer is also excellent.

In order to make the second resin layer particularly excellent in heat resistance, as described above, the thermoplastic resin (II) contained in the second thermoplastic resin composition is a structural unit derived from a maleimide compound. (Hereinafter referred to as “structural unit (u21)”). This structural unit (u21) may be derived from any resin component. That is, the graft polymerization resin (g21) may contain the structural unit (u21), and the (co) polymer (c21) may contain the structural unit (u21).
From the above viewpoint, the content of the structural unit (u21) is preferably 1 to 50% by mass with respect to the total amount of the structural unit constituting the thermoplastic resin (II) contained in the second thermoplastic resin composition. More preferably, it is 5-45 mass%, More preferably, it is 10-40 mass%. When there is too much content of the said structural unit (u21), the flexibility of a 2nd resin layer may fall.

  When the said thermoplastic resin (II) contains aromatic vinyl resin (II-1), this thermoplastic resin (II) may consist only of aromatic vinyl resin (II-1), and is aromatic. It may consist of vinyl resin (II-1) and other thermoplastic resins. Examples of other thermoplastic resins include polyethylene terephthalate resin, polybutylene terephthalate resin, polycarbonate resin, polyamide resin, and the like. When the thermoplastic resin (II) contains another thermoplastic resin, the content thereof is preferably 1 to 50 mass with respect to the thermoplastic resin (II) from the viewpoint of heat resistance and impact resistance. %.

〔式中、Ｒ^３は、ビニル基、アミノ基、アクリロイル基、メタクリロイル基及びエポキシ結合のうちの少なくとも１種を含む有機基であり、Ｒ^４は、互いに同一又は異なって、１又は２以上のハロゲン原子が置換してもよい炭化水素基であり、ｎは０又は１である。〕 In order to further improve the adhesiveness between the second resin layer and the first resin layer and the third resin layer disposed on both sides of the second resin layer, the second thermoplastic resin composition (II) And the composition formed by melt-kneading the silane coupling agent containing composition containing the silane coupling agent represented by following General formula (3) may be sufficient.

[Wherein R ³ is an organic group containing at least one of a vinyl group, an amino group, an acryloyl group, a methacryloyl group and an epoxy bond, and R ⁴ is the same or different from each other, It is a hydrocarbon group that a halogen atom may be substituted, and n is 0 or 1. ]

The silane coupling agent will be described.
The amino group used as R ³ in the general formula (3) may be any of a primary amino group, a secondary amino group, a tertiary amino group, and an alkylene polyamino group.
Examples of the organic group containing an epoxy bond include a γ-glycidoxypropyl group.

In addition, the hydrocarbon group that may be substituted by a halogen atom, which is used as R ⁴ in the general formula (3), is preferably an organic group having 1 to 10 carbon atoms, and is a linear or branched fatty acid. Either an aromatic hydrocarbon group or an aromatic hydrocarbon group may be used.

  Examples of the silane coupling agent represented by the general formula (3) include vinyl silane cups such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltris (β-methoxyethoxy) silane, and allyltrimethoxysilane. Ring agent; aminosilane cup such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane Ring agent: 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltriethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldiethoxysilane, etc. Acrylic silane coupling agent; methacryl silane such as 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane Coupling agent: γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ -An epoxy silane coupling agent such as glycidoxypropylmethyldiethoxysilane. These may be used alone or in combination of two or more.

The amount of the silane coupling agent used is preferably 0.05 to 20 parts by mass, more preferably 0.07 to 15 parts by mass with respect to 100 parts by mass of the thermoplastic resin (II). Preferably it is 0.1-10 mass parts. When the content of the silane coupling agent is in the above range, the adhesion between the obtained second resin layer and the first resin layer and the third resin layer disposed on both sides thereof is excellent.
The said silane coupling agent containing composition may also contain additives (after-mentioned) other than a silane coupling agent.

The method for producing the second thermoplastic resin composition by melt-kneading the silane coupling agent-containing composition is not particularly limited, and all components including the thermoplastic resin (II) and the silane coupling agent are melted. Kneading method; while melt-kneading thermoplastic resin (II) and silane coupling agent, adding other raw material components separately or continuously, and continuing melt-kneading; thermoplastic resin (II) And a method in which the silane coupling agent is added in portions or continuously while melt kneading the other raw material components, and the melt kneading is continued; the silane coupling agent while melt kneading the thermoplastic resin (II) And other raw material components may be added separately or continuously to continue the melt-kneading.
Examples of the apparatus used for melt kneading include a single screw extruder, a twin screw extruder, a Banbury mixer, a kneader, and a continuous kneader.

  The said 2nd thermoplastic resin composition may contain the additive mix | blended for film formation. This additive includes antioxidants, ultraviolet absorbers, anti-aging agents, colorants, fluorescent brighteners, weathering agents, fillers, antistatic agents, flame retardants, antifogging agents, antibacterial agents, antifungal agents, Antifouling agents, tackifiers and the like can be mentioned. Specific compounds and their blending amounts in these additives will be described later together with preferred embodiments of the solar cell back surface protective film of the present invention.

The said 2nd resin layer is a layer obtained using the 2nd thermoplastic resin composition formed by melt-kneading the 2nd raw material composition containing thermoplastic resin (II). This 2nd raw material composition may be the said silane coupling agent containing composition containing a silane coupling agent, and the composition which does not contain a silane coupling agent.
The melt kneading method and apparatus for the second raw material composition are not particularly limited. For example, it is melt kneaded under known conditions using a single screw extruder, twin screw extruder, Banbury mixer, kneader, continuous kneader, or the like. A second thermoplastic resin composition is produced.
The thickness of the second resin layer is usually 10 to 990 μm, preferably 20 to 500 μm.

  Next, as described above, the third resin layer is a layer mainly having a function of imparting flexibility to the solar cell back surface protective film of the present invention, and includes a third heat containing a thermoplastic resin (III). It is a layer obtained using a plastic resin composition.

  The glass transition temperature (Tg) of the thermoplastic resin (III) is preferably from the viewpoint of imparting sufficient flexibility to the solar cell back surface protective film of the present invention and imparting heat resistance to the third resin layer. It is 90 ° C to 200 ° C, more preferably 95 ° C to 180 ° C, still more preferably 100 ° C to 160 ° C, and particularly preferably 105 ° C to 140 ° C.

  The thermoplastic resin (III) is not particularly limited as long as it is a thermoplastic resin, and may be a silicon-free thermoplastic resin or a silicon-containing thermoplastic resin containing a silicon atom in the molecule. Also good. Moreover, you may use combining these.

Examples of the silicon-free thermoplastic resin include aromatic vinyl resin, polyolefin resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, saturated polyester resin, polycarbonate resin, acrylic resin, fluororesin, ethylene / vinyl acetate. Examples thereof include resins. These can be used alone or in combination of two or more.
The silicon-containing thermoplastic resin includes aromatic vinyl resin (silicon-containing aromatic vinyl resin), polyolefin resin (silicon-containing polyolefin resin), polyvinyl chloride resin (silicon-containing polyvinyl chloride resin), poly Vinylidene chloride resin (silicon-containing polyvinylidene chloride resin), saturated polyester resin (silicon-containing saturated polyester resin), polycarbonate resin (silicon-containing polycarbonate resin), polyamide resin (silicon-containing polyamide resin), acrylic resin (silicon-containing) Acrylic resin), fluororesin (silicon-containing fluororesin), silicon resin and the like. About these silicon-containing thermoplastic resins, the silicon-containing thermoplastic resin contained in the said 1st thermoplastic resin composition can be applied, and it can be used individually by 1 type or in combination of 2 or more types.
When the thermoplastic resin (III) contains a silicon-containing thermoplastic resin, the silicon-containing thermoplastic resin is a silicon-containing thermoplastic resin contained in the thermoplastic resin (I) and / or the thermoplastic resin. The silicon-containing thermoplastic resin that can be used for (II) may be the same or different.

  As the thermoplastic resin (III), an aromatic vinyl resin containing a structural unit derived from an aromatic vinyl compound (hereinafter referred to as “aromatic vinyl resin (III-1)” from the viewpoint of hydrolysis resistance, dimensional stability, and the like. ) ") Is preferred. The aromatic vinyl resin (III-1) may be a silicon-free thermoplastic resin or a silicon-containing thermoplastic resin (silicon-containing aromatic vinyl resin or the like) containing a silicon atom in the molecule. May be.

  As said aromatic vinyl resin (III-1), the graft | grafting obtained by superposing | polymerizing the monomer (henceforth "monomer (m31)") containing an aromatic vinyl compound in presence of rubber | gum. Polymerized resin (hereinafter referred to as “graft polymerized resin (g31)”); an aromatic vinyl-based polymer obtained by polymerizing a monomer (hereinafter referred to as “monomer (m32)”) containing an aromatic vinyl compound. Co) polymer (hereinafter referred to as “(co) polymer (c31)”); and a mixture of the graft polymerization resin (g31) and (co) polymer (c31) (hereinafter referred to as “mixture (y31)”). Said).

The said graft polymerization resin (g31) can be used individually by 1 type or in combination of 2 or more types.
Moreover, the said (co) polymer (c31) can be used individually by 1 type or in combination of 2 or more types.

  The monomer (m31) and the monomer (m32), the graft polymerization resin (g31), the (co) polymer (c31) and the mixture (y31), and their production methods are the same as the aromatic vinyl resin ( II-1) monomer (m21) and monomer (m22) used in the formation of graft polymer resin (g21), (co) polymer (c21) contained in the aromatic vinyl resin (II-1) ) And the mixture (y21) and their production methods can be applied. The same applies to the types and structures of the preferred monomer (m31) and monomer (m32) and the preferred type of rubber used for forming the graft polymerization resin (g31).

As the graft polymerization resin (g31), preferred resins are as follows.
(G31-1) Graft polymerization resin obtained by polymerizing a monomer comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of rubber (g31-2) In the presence of rubber, an aromatic vinyl compound In the presence of a graft polymerization resin (g31-3) rubber obtained by polymerizing a monomer comprising a vinyl cyanide compound and a maleimide compound, an aromatic vinyl compound, a vinyl cyanide compound and a methacrylic ester compound are used. Graft polymerization resin obtained by polymerizing the monomer

  The graft ratio of the graft polymerization resin (g31) is preferably 20 to 170%, more preferably 30 to 170%, still more preferably 40 to 150%. When this graft ratio is too low, the flexibility as a film may not be sufficient. On the other hand, if the graft ratio is too high, the viscosity of the third thermoplastic resin composition increases, and it may be difficult to reduce the thickness.

When the (co) polymer (c31) is a copolymer, preferred polymers are as follows.
(C31-1) a copolymer comprising a structural unit derived from an aromatic vinyl compound and a structural unit derived from a vinyl cyanide compound (c31-2) a structural unit derived from an aromatic vinyl compound, and vinyl cyanide A copolymer comprising a structural unit derived from a compound and a structural unit derived from a maleimide compound

  When the aromatic vinyl resin (III-1) is the mixture (y31), the content ratio of the graft polymerization resin (g31) and the (co) polymer (c31) is not particularly limited. Moreover, in the case where the aromatic vinyl resin (III-1) is the graft polymerization resin (g31) and the mixture (y31), the third thermoplastic resin composition is included in the third thermoplastic resin composition. The ratio of the total content of the rubber contained is preferably 3 to 40% by mass, more preferably 5 to 30% by mass with respect to the entire thermoplastic resin (III) from the viewpoint of impact resistance.

  In both cases where the aromatic vinyl resin (III-1) is composed of the graft polymerization resin (g31) and the mixture (y31), the aromatic vinyl resin (III-1) The intrinsic viscosity [η] (measured in methyl ethyl ketone at 30 ° C.) of the component soluble in acetone (however, when the rubber is an acrylic rubber, acetonitrile) is preferably 0.1 to 2.5 dl / g. More preferably, it is 0.2-1.5 dl / g, More preferably, it is 0.25-1.2 dl / g. When the intrinsic viscosity [η] is within the above range, the third thermoplastic resin composition is excellent in molding processability and the thickness accuracy of the third resin layer is also excellent.

In order to make the third resin layer particularly excellent in heat resistance, as described above, the thermoplastic resin (III) contained in the third thermoplastic resin composition is a structural unit derived from a maleimide compound. (Hereinafter referred to as “structural unit (u31)”). This structural unit (u31) may be derived from any resin component. That is, the graft polymerization resin (g31) may contain the structural unit (u31), and the (co) polymer (c31) may contain the structural unit (u31).
From the above viewpoint, the content of the structural unit (u31) is preferably 1 to 40% by mass with respect to the total amount of the structural units constituting the thermoplastic resin (III) contained in the third thermoplastic resin composition. More preferably, it is 2-35 mass%, More preferably, it is 5-30 mass%. When there is too much content of the said structural unit (u31), the flexibility of a 3rd resin layer may fall.

  When the thermoplastic resin (III) includes an aromatic vinyl resin (III-1), the thermoplastic resin (III) may be composed only of the aromatic vinyl resin (III-1) or may be aromatic. It may consist of vinyl resin (III-1) and other thermoplastic resins. Examples of other thermoplastic resins include polyethylene terephthalate resin, polybutylene terephthalate resin, polycarbonate resin, polyamide resin, and the like. When the thermoplastic resin (III) contains another thermoplastic resin, the content thereof is preferably 1 to 50 mass with respect to the thermoplastic resin (III) from the viewpoint of heat resistance and impact resistance. %.

  Similar to the second thermoplastic resin composition, the third thermoplastic resin composition includes a silane coupling agent including the thermoplastic resin (III) and a silane coupling agent represented by the general formula (3). The composition formed by melt-kneading the agent-containing composition may be used.

  The said 3rd thermoplastic resin composition may contain the additive mix | blended for film formation. This additive includes antioxidants, ultraviolet absorbers, anti-aging agents, colorants, fluorescent brighteners, weathering agents, fillers, antistatic agents, flame retardants, antifogging agents, antibacterial agents, antifungal agents, Antifouling agents, tackifiers and the like can be mentioned. Specific compounds and their blending amounts in these additives will be described later together with preferred embodiments of the solar cell back surface protective film of the present invention.

The said 3rd resin layer is a layer obtained using the 3rd thermoplastic resin composition formed by melt-kneading the 3rd raw material composition containing thermoplastic resin (III). The third raw material composition may be the silane coupling agent-containing composition containing a silane coupling agent or a composition not containing a silane coupling agent.
The method for melting and kneading the third raw material composition and the apparatus therefor are not particularly limited. For example, it is melt kneaded under known conditions using a single screw extruder, twin screw extruder, Banbury mixer, kneader, continuous kneader, or the like. A third thermoplastic resin composition is produced.
The thickness of the third resin layer is usually 5 to 500 μm, preferably 10 to 400 μm.

Next, the additive contained in said 1st thermoplastic resin composition, 2nd thermoplastic resin composition, and 3rd thermoplastic resin composition is demonstrated.
As the colorant, either a pigment or a dye may be used, and usually one or more are selected in consideration of appearance and the like.
Examples of the white colorant include titanium oxide, zinc oxide, calcium carbonate, barium sulfate, calcium sulfate, alumina, silica, 2PbCO ₃ · Pb (OH) ₂ , [ZnS + BaSO ₄ ], talc, and gypsum.
Also, black colorants include carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, etc.), graphite, copper oxide, manganese dioxide, aniline black, titanium black, activated carbon, ferrite (nonmagnetic ferrite) , Magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complexes, complex oxides, anthraquinone compounds, perylene compounds, and the like.
Furthermore, a cyan colorant (blue-green color material), a magenta colorant (red purple color material), and a yellow colorant (yellow color material) can also be used.
Since the solar cell element is often a dark color, the colorant is selected so that the solar cell module also exhibits the same color. When coloring in a dark color system, it may be expressed by a single compound of a dark color colorant, or may be expressed by a combination of two or more colorants.
Further, the dark colorant is blended in at least one of the first thermoplastic resin composition, the second thermoplastic resin composition, and the third thermoplastic resin composition according to the purpose.

Examples of the antioxidant include hindered amine compounds, hydroquinone compounds, hindered phenol compounds, sulfur-containing compounds, and phosphorus-containing compounds. These can be used alone or in combination of two or more.
The content of the antioxidant is a thermoplastic resin (I) containing a silicon-containing thermoplastic resin contained in the first thermoplastic resin composition, the second thermoplastic resin composition or the third thermoplastic resin composition. The amount is preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the thermoplastic resin (II) or the thermoplastic resin (III).

Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, and triazine compounds. These can be used alone or in combination of two or more.
The content of the ultraviolet absorber is a thermoplastic resin (I) containing a silicon-containing thermoplastic resin contained in the first thermoplastic resin composition, the second thermoplastic resin composition or the third thermoplastic resin composition. The amount is preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the thermoplastic resin (II) or the thermoplastic resin (III).

Examples of the anti-aging agent include naphthylamine compounds, diphenylamine compounds, p-phenylenediamine compounds, quinoline compounds, hydroquinone derivative compounds, monophenol compounds, bisphenol compounds, trisphenol compounds, polyphenol compounds, thiols. Examples thereof include bisphenol compounds, hindered phenol compounds, phosphite compounds, imidazole compounds, nickel dithiocarbamate salts, phosphoric compounds, and the like. These can be used alone or in combination of two or more.
The content of the antioxidant is a thermoplastic resin (I) containing a silicon-containing thermoplastic resin contained in the first thermoplastic resin composition, the second thermoplastic resin composition, or the third thermoplastic resin composition. The amount is preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the thermoplastic resin (II) or the thermoplastic resin (III).

Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, butyl octyl phthalate, di- (2-ethylhexyl) phthalate, diisooctyl phthalate, and diisodecyl phthalate; dimethyl adipate , Diisobutyl adipate, di- (2-ethylhexyl) adipate, diisooctyl adipate, diisodecyl adipate, octyl decyl adipate, di- (2-ethylhexyl) azelate, diisooctyl azelate, diisobutyl azelate, dibutyl sebacate, di- Fatty acid esters such as (2-ethylhexyl) sebacate, diisooctyl sebacate; trimellitic acid isodecyl ester, trimellitic acid octy Esters, trimellitic acid esters such as trimellitic acid n-octyl ester, trimellitic acid isononyl ester; di- (2-ethylhexyl) fumarate, diethylene glycol monooleate, glyceryl monoricinolate, trilauryl phosphate, tristearyl phosphate, Examples include tri- (2-ethylhexyl) phosphate and epoxidized soybean oil. These can be used alone or in combination of two or more.
The content of the plasticizer is a thermoplastic resin (I) containing a silicon-containing thermoplastic resin contained in the first thermoplastic resin composition, the second thermoplastic resin composition or the third thermoplastic resin composition, The amount is preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the thermoplastic resin (II) or the thermoplastic resin (III).

  In the solar cell back surface protective film of the present invention, since the first resin layer contains a silicon-containing thermoplastic resin, the first resin layer-side surface is bonded to a filler portion for embedding the solar cell element. Therefore, it is excellent in adhesiveness between the first resin layer and a filler part containing an ethylene / vinyl acetate copolymer composition or the like that embeds the solar cell element without providing an adhesive layer. And the back surface protection film for solar cells of this invention is made to adhere | attach with the exposed surface of the said filler part in the surface (upper surface side) of the 1st resin layer 11 shown by FIG.1 and FIG.2. Manufactured.

When the back surface protective film for solar cells of the present invention radiates light having a wavelength of 400 to 1,400 nm to the surface of the first resin layer in the back surface protective film for solar cells, the reflectance with respect to the light is 50% or more. In a certain film (hereinafter referred to as “film (X) of the present invention”) and the first resin layer, the transmittance for light having a wavelength of 800 to 1,400 nm is 60% or more, and light having a wavelength of 400 to 700 nm. In the case where light having a wavelength of 800 to 1,400 nm is radiated to the surface of the first resin layer in the solar cell back surface protective film, the reflectance to the light is 50%. It can be set as the above film (henceforth "the film (Y) of this invention").
According to the film (X) of the present invention, since the reflectivity for most wavelengths of sunlight is excellent, sunlight leaks from the gap between adjacent solar cell elements toward the back surface protective film for solar cells. Sometimes, sunlight can be reflected from the first resin layer, and the reflected light can be supplied to the back surface of the solar cell element and used for photoelectric conversion to improve power generation efficiency.
Moreover, according to the film (Y) of this invention, when sunlight leaks toward the back surface protective film for solar cells from the gap | interval of an adjacent solar cell element, in the 1st resin layer, the said wavelength 800- Since light of 1,400 nm is transmitted and heat storage due to this light is suppressed, heat storage of the filler portion bonded to the first resin layer is suppressed. And the heat storage in the solar cell module formed using this film (Y) is also suppressed, and the fall of power generation efficiency can be suppressed.

In the film (X) of the present invention, the reflectance with respect to light having a wavelength of 400 to 1,400 nm is measured by emitting light to the surface of the first resin layer in the film (X) having a thickness of 30 to 1,000 μm. Is. The reflectance is 50% or more, preferably 60% or more, more preferably 70% or more. The higher the reflectance, the more the light can be reflected toward the solar cell element disposed in the filler portion, and the photoelectric conversion efficiency can be improved.
In the present invention, “the reflectance with respect to light having a wavelength of 400 to 1,400 nm is 50% or more” means that the reflectance of light in the wavelength region from 400 nm to 1,400 nm is 400 nm or every 1,400 nm to 20 nm. This means that the average value calculated using each reflectance is 50% or more, and it does not require that all the reflectances of light in the above-mentioned wavelength region are 50% or more.

  In the film (X) of the present invention, when light having a wavelength of 400 to 1,400 nm is emitted only to the film constituting the first resin layer (thickness of 5 to 1,000 μm), the reflectance with respect to this light is preferably Is 50% or more, more preferably 60% or more, still more preferably 70% or more.

In the film (X) of the present invention, the L value (brightness) measured on the surface on the first resin layer side is 60 or more in order to set the reflectance to light with a wavelength of 400 to 1,400 nm to 50% or more. Preferably there is.
As film (X) satisfying the above properties, it is preferable that at least one of the first resin layer, the second resin layer, and the third resin layer contains a white colorant. All the resin layers may contain the same white colorant, or may contain different white colorants. As the white colorant, titanium oxide is preferable.

When the first resin layer, the second resin layer, and the third resin layer contain a white colorant, the content ratio of the white colorant in any layer is relative to light having a wavelength of 400 to 1,400 nm. From the viewpoint of reflectivity, 100 parts by mass of the thermoplastic resin (I) containing the silicon-containing thermoplastic resin, 100 parts by mass of the thermoplastic resin (II), and 100 parts by mass of the thermoplastic resin (III). These are preferably 1 to 45 parts by mass, more preferably 3 to 40 parts by mass, and still more preferably 5 to 30 parts by mass. When there is too much content of this white type coloring agent, the flexibility of the film (X) of this invention may fall.
In addition, if it does not reduce the reflectance with respect to the said light to the surface of the 1st resin layer of the film (X) of this invention to less than 50%, according to the objective, a use, etc., further another colorant is added. It may be used. When other colorant is used, the content thereof is 100 parts by mass of the thermoplastic resin (I) containing the silicon-containing thermoplastic resin, 100 parts by mass of the thermoplastic resin (II), and the thermoplastic resin (III) 100. All are usually 5 parts by mass or less with respect to parts by mass.

  In the film (X) of the present invention, it is particularly preferable that the L value measured only in the first resin layer is 60 or more. Therefore, in the film (X) of the present invention, the first resin layer is preferably a white resin layer containing a white colorant.

In the film (X) of the present invention, when the first resin layer contains a white colorant, light having a wavelength of 400 to 1,400 nm is radiated to a film having a thickness of 5 to 500 μm constituting the first resin layer. The reflectance is preferably 50% or more. In this case, the configuration and properties (transparency, colorability, etc.) of the second resin layer and the third resin layer are not particularly limited.
The second resin layer and the third resin layer may be white resin layers in order to make the reflectance of the light on the surface of the first resin layer more reliable. This white resin layer can be colored with a white colorant. The second resin layer and the third resin layer are not white resin layers, and at least one of them may be colored in a dark color. When said 2nd resin layer and / or said 3rd resin layer contain another colorant, the other colorant contained in the 2nd thermoplastic resin composition and 3rd thermoplastic resin composition which form each layer The content of is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin (II) and 100 parts by mass of the thermoplastic resin (III). 5 parts by mass.

When the first resin layer is a white resin layer and only the film constituting the first resin layer has a reflectance of less than 50% with respect to light having a wavelength of 400 to 1,400 nm, the second resin layer And / or the third resin layer is preferably a resin layer containing a white colorant. The content of the white colorant at this time is 100 parts by mass of the thermoplastic resin (II) and the thermoplastic resin (III) 100 from the viewpoint of light reflectivity on the surface of the first resin layer. Preferably all are 5-40 mass parts with respect to a mass part, More preferably, it is 10-35 mass parts.
When the first resin layer is a resin layer containing a white colorant and only the film constituting the first resin layer has a reflectance of less than 50%, the second resin layer Preferably contains a white colorant, and the third resin layer contains another colorant that is colored in a dark color. In this case, the content of the white colorant in the first resin layer is less than 1 part by mass with respect to 100 parts by mass of the thermoplastic resin (I) including the silicon-containing thermoplastic resin, and in the second resin layer. The content of the white colorant is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass, and the content of the other colorant in the third resin layer is preferably 0.01 to 10 parts by mass. More preferably, it can be 0.02 to 5 parts by mass.

  In the film (X) of the present invention, when the first resin layer is not a white resin layer, the first resin layer does not contain other colorant, and the second resin layer and / or the third resin. It is preferred that the layer contains a white colorant. When the second resin layer and / or the third resin layer contains a white colorant, the content thereof is 100 parts by mass of the thermoplastic resin (II) and heat from the viewpoint of reflectivity to the light. The amount is preferably 5 to 40 parts by mass, more preferably 10 to 35 parts by mass with respect to 100 parts by mass of the plastic resin (III).

  In the film (X) of the present invention, as exemplified above, when at least one of the first resin layer, the second resin layer, and the third resin layer contains a white colorant When sunlight leaks from the gap between adjacent solar cell elements, light having a wavelength of 400 to 1,400 nm is reflected on the surface of the first resin layer, and this reflected light is supplied to the back surface of the solar cell element. It can be used for photoelectric conversion to improve power generation efficiency.

On the other hand, in the film (Y) of the present invention, the transmittance with respect to light with a wavelength of 800 to 1,400 nm and the absorption with respect to light with a wavelength of 400 to 700 nm are the same as those of the first resin layer with a thickness of 30 to 1,000 μm. It is the measured value measured by radiating each light only to the constituting film.
The transmittance is 60% or more, preferably 65% or more, and more preferably 70% or more. As the transmittance is higher, heat storage due to light having a wavelength of 800 to 1,400 nm is suppressed in the first resin layer, so that heat storage of the filler portion bonded to the first resin layer is also suppressed. And the thermal storage of the solar cell module formed using this film (Y) is suppressed, and electric power generation efficiency can be improved.
In the present invention, “the transmittance with respect to light having a wavelength of 800 to 1,400 nm is 60% or more” means that the transmittance of light in the wavelength region from 800 nm to 1,400 nm using the film constituting the first resin layer. Is measured every 800 nm or from 1,400 nm to 20 nm, and the average value calculated using each transmittance is 60% or more, and the light transmittance in the above wavelength range is all 60% or more. It is not required to be.

The light absorptance is 60% or more, preferably 70% or more, and more preferably 80% or more. The higher the absorptance, the lower the lightness of the first resin layer, and the dark first resin layer, that is, the dark color solar cell back surface protective film is formed. Thereby, when a solar cell is arrange | positioned on the roof etc. of a house, it is excellent in an external appearance property and designability.
In the present invention, “the transmittance for light having a wavelength of 400 to 700 nm is 60% or more” means that the light absorption rate in the wavelength region from 400 nm to 700 nm is 400 nm or Measured every 700 nm to 20 nm, meaning that the average value calculated using each absorptivity is 60% or more, and requires that all the absorptances of light in the above wavelength range are 60% or more is not.

In the film (Y) of the present invention, the reflectance for light having a wavelength of 800 to 1,400 nm is measured by emitting light to the surface of the first resin layer in the film (Y). The reflectance is 50% or more, preferably 60% or more, more preferably 70% or more. The higher the reflectance, the more the light having the above wavelength can be reflected toward the solar cell element arranged in the filler portion, and the photoelectric conversion efficiency can be improved.
In the present invention, “the reflectance with respect to light having a wavelength of 800 to 1,400 nm is 50% or more” means reflection of light in a wavelength region from 800 nm to 1,400 nm in the first resin layer of the film (Y). The ratio is measured every 800 nm or 1,400 nm to 20 nm, and the average value calculated using each reflectance is 50% or more, and the reflectance of light in the above wavelength range is all 50% or more. It is not required to be.
In the film (Y) of the present invention, the transmittance for light having a wavelength of 400 to 800 nm is not particularly limited.

In the said film (Y), in the film which comprises a 1st resin layer, the transmittance | permeability with respect to the light of wavelength 800-1400nm shall be 60% or more, and the absorption factor with respect to the light of wavelength 400-700 nm shall be 60% or more. Furthermore, the film constituting the first resin layer preferably has a property of absorbing visible light and transmitting infrared light.
Therefore, the first thermoplastic resin composition constituting the first resin layer satisfying the above properties includes a silicon-containing thermoplastic resin and a colorant having a property of absorbing visible light and transmitting infrared light (hereinafter referred to as “ It is preferably a composition containing “infrared transparent colorant”.

  The infrared transmissive colorant usually has a color other than white, and is preferably a dark color such as black, brown, dark blue, or dark green. By using a dark-colored infrared transmissive colorant, the back surface protective film for solar cells having an excellent dark-colored appearance is provided without impairing the adhesion between the first resin layer and the exposed surface of the filler portion, and the same A solar cell module can be provided.

〔式中、Ｒ^５及びＲ^６は、互いに同一又は異なって、ブチル基、フェニルエチル基、メトキシエチル基又は４−メトキシフェニルメチル基である。〕

〔式中、Ｒ^７及びＲ^８は、互いに同一又は異なって、フェニレン基、３−メトキシフェニレン基、４−メトキシフェニレン基、４−エトキシフェニレン基、炭素数１〜３のアルキルフェニレン基、ヒドロキシフェニレン基、４，６−ジメチルフェニレン基、３，５−ジメチルフェニレン基、３−クロロフェニレン基、４−クロロフェニレン基、５−クロロフェニレン基、３−ブロモフェニレン基、４−ブロモフェニレン基、５−ブロモフェニレン基、３−フルオロフェニレン基、４−フルオロフェニレン基、５−フルオロフェニレン基、ナフチレン基、ナフタレンジイル基、ピリジレン基、２，３−ピリジンジイル基、３，４−ピリジンジイル基、４−メチル−２，３−ピリジンジイル基、５−メチル−２，３−ピリジンジイル基、６−メチル−２，３−ピリジンジイル基、５−メチル−３，４−ピリジンジイル基、４−メトキシ−２，３−ピリジンジイル基又は４−クロロ−２，３−ピリジンジイル基である。〕

〔式中、Ｒ^７及びＲ^８は、互いに同一又は異なって、フェニレン基、３−メトキシフェニレン基、４−メトキシフェニレン基、４−エトキシフェニレン基、炭素数１〜３のアルキルフェニレン基、ヒドロキシフェニレン基、４，６−ジメチルフェニレン基、３，５−ジメチルフェニレン基、３−クロロフェニレン基、４−クロロフェニレン基、５−クロロフェニレン基、３−ブロモフェニレン基、４−ブロモフェニレン基、５−ブロモフェニレン基、３−フルオロフェニレン基、４−フルオロフェニレン基、５−フルオロフェニレン基、ナフチレン基、ナフタレンジイル基、ピリジレン基、２，３−ピリジンジイル基、３，４−ピリジンジイル基、４−メチル−２，３−ピリジンジイル基、５−メチル−２，３−ピリジンジイル基、６−メチル−２，３−ピリジンジイル基、５−メチル−３，４−ピリジンジイル基、４−メトキシ−２，３−ピリジンジイル基又は４−クロロ−２，３−ピリジンジイル基である。〕 Examples of the infrared transmissive colorant include perylene pigments. As the perylene pigment, compounds represented by the following general formulas (4) to (6) can be used.

[Wherein, R ⁵ and R ⁶ are the same or different from each other, and are a butyl group, a phenylethyl group, a methoxyethyl group, or a 4-methoxyphenylmethyl group. ]

[In the formula, R ⁷ and R ⁸ are the same or different from each other, and include a phenylene group, a 3-methoxyphenylene group, a 4-methoxyphenylene group, a 4-ethoxyphenylene group, an alkylphenylene group having 1 to 3 carbon atoms, and a hydroxyphenylene. Group, 4,6-dimethylphenylene group, 3,5-dimethylphenylene group, 3-chlorophenylene group, 4-chlorophenylene group, 5-chlorophenylene group, 3-bromophenylene group, 4-bromophenylene group, 5- Bromophenylene group, 3-fluorophenylene group, 4-fluorophenylene group, 5-fluorophenylene group, naphthylene group, naphthalenediyl group, pyridylene group, 2,3-pyridinediyl group, 3,4-pyridinediyl group, 4- Methyl-2,3-pyridinediyl group, 5-methyl-2,3-pyridinediyl group, 6- Le-2,3-pyridinediyl group, 5-methyl-3,4-pyridinediyl group, 4-methoxy-2,3-pyridinediyl group, or a 4-chloro-2,3-pyridinediyl group. ]

[In the formula, R ⁷ and R ⁸ are the same or different from each other, and include a phenylene group, a 3-methoxyphenylene group, a 4-methoxyphenylene group, a 4-ethoxyphenylene group, an alkylphenylene group having 1 to 3 carbon atoms, and a hydroxyphenylene. Group, 4,6-dimethylphenylene group, 3,5-dimethylphenylene group, 3-chlorophenylene group, 4-chlorophenylene group, 5-chlorophenylene group, 3-bromophenylene group, 4-bromophenylene group, 5- Bromophenylene group, 3-fluorophenylene group, 4-fluorophenylene group, 5-fluorophenylene group, naphthylene group, naphthalenediyl group, pyridylene group, 2,3-pyridinediyl group, 3,4-pyridinediyl group, 4- Methyl-2,3-pyridinediyl group, 5-methyl-2,3-pyridinediyl group, 6- Le-2,3-pyridinediyl group, 5-methyl-3,4-pyridinediyl group, 4-methoxy-2,3-pyridinediyl group, or a 4-chloro-2,3-pyridinediyl group. ]

In addition, as the perylene-based pigment, commercially available products such as “Paligen Black S 0084”, “Palogen Black L 0086”, “Lumogen Black FK4280”, “Lumogen Black FK4281” (all of which are trade names manufactured by BASF) are used. Can be used.
The infrared transmissive colorant can be used alone or in combination of two or more.

The content ratio of the infrared transmitting colorant in the first thermoplastic resin composition is based on 100 parts by mass of the thermoplastic resin (I) containing the silicon-containing thermoplastic resin from the viewpoints of transmittance and absorbability with respect to each light. On the other hand, it is preferably 5 parts by mass or less, more preferably 0.1 to 5 parts by mass.
In addition, in the said 1st resin layer, if it does not reduce the said transmittance | permeability and absorptivity, according to the objective, a use, etc., another coloring agent can be included. For example, a solar cell module having various appearances can be obtained by using a yellow pigment, a blue pigment, or the like as a colorant other than the infrared-transmitting colorant and using the following combinations.
[1] Brown coloration by combination of black-based infrared transmitting colorant and yellow pigment [2] Dark blue coloration by combination of black-based infrared transmitting colorant and blue pigment When other colorant is used, The content in the thermoplastic resin composition is usually 200 parts by mass or less, preferably 0.01 to 100 parts by mass with respect to 100 parts by mass of the infrared transmitting colorant.

  Carbon black is known as a dark colorant. Since this carbon black absorbs light having a wavelength in the infrared region, the first resin layer that stores heat when sunlight leaks from the gap between adjacent solar cell elements toward the film (Y) of the present invention. From the above, the temperature of the filler part including the solar cell element may be increased, and the power generation efficiency may be decreased. By using the infrared transmissive colorant, the design property is not decreased without decreasing the power generation efficiency. And excellent durability.

In the film (Y) of the present invention, when the first resin layer contains the infrared transmissive colorant, 60% or more of light having a wavelength of 800 to 1,400 nm is transmitted through the first resin layer. The second resin layer and / or the third resin layer is preferably a layer having a high reflectance with respect to the light. By having such an action, light having a wavelength of 800 to 1,400 nm transmitted through the first resin layer can be used for photoelectric conversion. In other words, the film constituting the second resin layer and / or the film constituting the third resin layer may have a reflectance with respect to the light of at least 50%. Specifically, when light having the above wavelength is emitted to a film having a thickness of 10 to 990 μm composed of the second resin layer and a film having a thickness of 5 to 500 μm composed of the third resin layer, the reflectance Is preferably 50% or more, or any one of the reflectances is preferably 50% or more.
In order to obtain such a film (Y), it is preferable that the second resin layer and / or the third resin layer contain a white colorant. The content of the white colorant is preferably 100 parts by mass of the thermoplastic resin (II) and 100 parts by mass of the thermoplastic resin (III) from the viewpoint of reflectivity to light. It is 1-45 mass parts, More preferably, it is 3-40 mass parts, More preferably, it is 5-30 mass parts. When there is too much content of this white type coloring agent, the flexibility of the film (Y) of this invention may fall.
The second resin layer and / or the third resin layer may further contain other colorants depending on the purpose, application, etc., unless the reflectance with respect to the light is greatly reduced. When other colorants are used, the content thereof is usually 10 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin (II) and 100 parts by mass of the thermoplastic resin (III). . In this case, the first resin layer preferably does not substantially contain a white colorant. However, when the white colorant is contained, the upper limit of the content is usually 3 parts by mass. The amount is preferably 1 part by mass.

  As said film (Y), the said 1st resin layer and said 2nd resin layer can also be set as the aspect containing an infrared rays transparent coloring agent and the said 3rd resin layer containing a white-type coloring agent.

  Moreover, in the back surface protective film for solar cells of the present invention, as an aspect excluding the films (X) and (Y), the first resin layer does not contain a colorant, and the second resin layer is colored with infrared transmission. It is also possible to include an agent, and the third resin layer may include a white colorant.

A preferable aspect is shown below as a back surface protective film for solar cells of this invention.
(A) The first resin layer is a layer obtained using a first thermoplastic resin composition containing a silicon-containing thermoplastic resin and a white colorant, and the second resin layer is a thermoplastic resin (II). And a layer obtained by using the second thermoplastic resin composition not containing the white colorant, and the third resin layer contains the thermoplastic resin (III) and does not contain the white colorant. Film (a) The first resin layer, which is a layer obtained by using the three thermoplastic resin composition, was obtained by using the first thermoplastic resin composition containing the silicon-containing thermoplastic resin and the white colorant. The second resin layer is a layer obtained by using the second thermoplastic resin composition containing the thermoplastic resin (II) and not containing the white colorant, and the third resin layer is a heat In a layer obtained using a third thermoplastic resin composition containing a plastic resin (III) and a white colorant The film (c) is a layer obtained using a first thermoplastic resin composition containing a silicon-containing thermoplastic resin and a white colorant, and the second resin layer is a thermoplastic resin ( II) and a layer obtained using the second thermoplastic resin composition containing the white colorant, and the third resin layer contains the thermoplastic resin (III) and does not contain the white colorant. A layer obtained by using a first thermoplastic resin composition containing a silicon-containing thermoplastic resin and a white colorant, wherein the film (d) the first resin layer is a layer obtained using the thermoplastic resin composition. The second resin layer is a layer obtained by using a second thermoplastic resin composition containing a thermoplastic resin (II) and a white colorant, and the third resin layer is a thermoplastic resin (III ) And a third thermoplastic resin composition containing a white colorant. Beam above, and preferred examples as the film (X).

Moreover, a preferable example as said film (Y) is shown below.
(E) The first resin layer is a layer obtained using a first thermoplastic resin composition containing a silicon-containing thermoplastic resin and an infrared transmitting colorant, and the second resin layer is a thermoplastic resin (II ) And a second thermoplastic resin composition containing no white colorant, and the third resin layer contains a thermoplastic resin (III) and a white colorant. A layer obtained by using a first thermoplastic resin composition in which a film (f) first resin layer, which is a layer obtained by using a plastic resin composition, contains a silicon-containing thermoplastic resin and an infrared transmitting colorant. The second resin layer is a layer obtained by using a second thermoplastic resin composition containing a thermoplastic resin (II) and a white colorant, and the third resin layer is a thermoplastic resin (III ) And a layer obtained using a third thermoplastic resin composition not containing a white colorant A certain film (G) is a layer obtained by using a first thermoplastic resin composition containing a silicon-containing thermoplastic resin and an infrared transmitting colorant, and the second resin layer is a thermoplastic resin. (II) and a third thermoplastic resin obtained by using a second thermoplastic resin composition containing a white colorant, wherein the third resin layer contains a thermoplastic resin (III) and a white colorant. Film that is a layer obtained by using a resin composition

  In the back surface protective film for solar cells of the present invention, the silicon-containing thermoplastic resin contained in the first resin layer is a silicon-containing aromatic vinyl resin, and the thermoplastic resin (II) contained in the second resin layer. ) And the thermoplastic resin (III) contained in the third resin layer is preferably an aromatic vinyl resin. By setting it as the said structure, it is excellent in hydrolysis resistance, dimensional stability, and impact resistance. The thermoplastic resin (II) and the thermoplastic resin (III) may be the same as or different from each other. The aromatic vinyl resin is particularly preferably a graft polymerization resin. In this case, the content ratios of the rubber (component) contained in the first resin layer and the second resin layer may be the same or different.

  The back surface protective film for a solar cell of the present invention can further include a water vapor barrier layer and / or a back surface protective layer on the outer surface of the third resin layer. When the back surface protective film for solar cells of this invention is equipped with both a water vapor | steam barrier layer and a back surface protective layer, it is preferable to provide in order of a 3rd resin layer, a water vapor | steam barrier layer, and a back surface protective layer (refer FIG. 2). That is, the back surface protective film 1B for solar cells in FIG. 2 is a laminated film that includes a first resin layer 11, a second resin layer 12, a third resin layer 13, a water vapor barrier layer 14, and a back surface protective layer 15 in sequence. is there.

The water vapor barrier layer has a moisture permeability (also referred to as “water vapor permeability”) measured under conditions of a temperature of 40 ° C. and a humidity of 90% RH in accordance with JIS K7129, preferably 3 g / (m ² · day) or less. More preferably, the layer has a performance of 1 g / (m ² · day) or less, and further preferably 0.7 g / (m ² · day) or less.
The water vapor barrier layer is preferably a layer made of an electrically insulating material.

The water vapor barrier layer may have a single layer structure or a multilayer structure made of one kind of material, or may have a single layer structure or a multilayer structure made of two or more kinds of materials. In the present invention, it is preferable that a vapor barrier layer is formed by using a vapor deposition film in which a film made of a metal and / or metal oxide is formed on the surface thereof as a material for forming a vapor barrier layer. Both the metal and the metal oxide may be a single substance or two or more kinds.
The water vapor barrier layer forming material may be a three-layer film in which a film made of a metal and / or metal oxide is disposed between an upper resin layer and a lower resin layer.

Examples of the metal include aluminum.
Examples of the metal oxide include oxides of elements such as silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, and yttrium. Of these, silicon oxide, aluminum oxide, and the like are particularly preferable from the viewpoint of water vapor barrier properties.
The film made of the metal and / or metal oxide may be formed by a method such as plating, vacuum deposition, ion plating, sputtering, plasma CVD, or microwave CVD. Two or more of these methods may be combined.

  As a resin layer in the above-mentioned vapor deposition film, polyester films such as polyethylene terephthalate film and polyethylene naphthalate; polyolefin films such as polyethylene and polypropylene; polyvinylidene chloride film, polyvinyl chloride film, fluororesin film, polysulfone film, polystyrene film, polyamide Examples thereof include a film, a polycarbonate film, a polyacrylonitrile film, and a polyimide film. The thickness of this resin film is preferably 5 to 50 μm, more preferably 8 to 20 μm.

  The said water vapor | steam barrier layer shall be formed using the commercial item. For example, a film or sheet such as “Tech Barrier AX” manufactured by Mitsubishi Plastics, “GX Film” manufactured by Toppan Printing Co., Ltd., “Ecosia VE500” manufactured by Toyobo Co., Ltd. Can do.

  The arrangement of the water vapor barrier layer facing the third resin layer is not particularly limited. When a vapor deposition film is used as the material for forming the water vapor barrier layer, a film made of metal and / or metal oxide may be bonded to the third resin layer, or the vapor deposition film may be on the outside (surface side). Good.

  The thickness of the water vapor barrier layer is preferably 5 to 300 μm, more preferably 8 to 250 μm, and still more preferably 10 to 200 μm. If the water vapor barrier layer is too thin, the water vapor barrier property may be insufficient. If it is too thick, the flexibility as the back surface protective film for solar cell of the present invention may not be sufficient.

  When the back surface protective film for solar cells of the present invention includes a water vapor barrier layer, an adhesive layer can be provided between the third resin layer and the water vapor barrier layer. The configuration of the adhesive layer can be a polyurethane resin composition, an epoxy resin composition, an acrylic resin composition, or the like.

The back surface protective layer includes a composition (hereinafter referred to as “fourth thermoplastic resin composition”) containing a thermoplastic resin (hereinafter referred to as “thermoplastic resin (IV)”) and imparts scratch resistance. It is a layer to do.
The thermoplastic resin (IV) is not particularly limited as long as it is a resin having thermoplasticity. The thermoplastic resin (IV) is, for example, a saturated polyester resin such as polyethylene terephthalate, polyethylene naphthalate, or polybutylene terephthalate; a polyolefin resin such as polyethylene or polypropylene; a polyvinyl fluoride, an ethylene / tetrafluoroethylene copolymer, or the like. Fluorine resin; Polycarbonate resin; Polyamide resin; Polyarylate resin; Polyethersulfone resin; Polysulfone resin; Polyacrylonitrile; Cellulose resin such as cellulose acetate; Acrylic resin; Aromatic vinyl resin such as polystyrene and ABS resin . These can be used alone or in combination of two or more. Of these, saturated polyester resins such as polyethylene terephthalate and fluororesins are preferred.

The fourth thermoplastic resin composition may contain an additive depending on the purpose and application. These additives include colorants, antioxidants, UV absorbers, anti-aging agents, plasticizers, optical brighteners, weathering agents, fillers, antistatic agents, flame retardants, antifogging agents, antibacterial agents, Examples include fungicides, antifouling agents, tackifiers, and silane coupling agents. Specific compounds in these additives and their blending amounts will be described later.
The back surface protective layer may have a single layer structure or a multilayer structure. In the case of the latter, the film etc. which consist of the mutually same composition may be laminated | stacked, and the film etc. which consist of a mutually different composition may be laminated | stacked. Furthermore, the layer which consists of another substance or another composition may be formed in one side or both surfaces, such as a film which consists of said 4th thermoplastic resin composition.

The back protective layer is preferably a flame retardant resin layer, may be a layer derived from a fourth thermoplastic resin composition containing a flame retardant, and may have an aromatic ring or heterocycle in the molecular skeleton. It may be a layer derived from a composition containing atoms, and an organic / inorganic hybrid material is laminated on one side or both sides of a film made of the fourth thermoplastic resin composition (regardless of flame retardant). It may be a layer formed.
As for the flame retardancy of the back surface protective layer, it is preferable that the flammability according to the UL94 standard is a class of VTM-2 or higher.
As the back surface protective layer, a commercially available resin film having flame retardancy can also be used. For example, “Melinex 238” (product name) manufactured by Teijin DuPont, “SR55” (product name) manufactured by SKC, “Lumirror X10P”, “Lumirror X10S”, “Lumirror ZV10” (above, product name) manufactured by Toray Industries, Inc. Can be used.

  The thickness of the said back surface protective layer is 10-500 micrometers normally, Preferably it is 15-400 micrometers, More preferably, it is 20-300 micrometers. If the back surface protective layer is too thin, scratch resistance may not be sufficient. On the other hand, when too thick, the flexibility as the back surface protective film for solar cell of the present invention may not be sufficient.

  When the back surface protective film for solar cells of the present invention includes a back surface protective layer, an adhesive layer can be provided between the third resin layer and the back surface protective layer. When a water vapor barrier layer and a back surface protective layer are sequentially provided on the third resin layer side, an adhesive layer can be provided between the water vapor barrier layer and the back surface protective layer. The configuration of the adhesive layer can be a polyurethane resin composition, an epoxy resin composition, an acrylic resin composition, or the like.

  The thickness of the back surface protective film for solar cells of the present invention is preferably 30 to 1,000 μm, more preferably 40 to 900 μm, and still more preferably 50 to 800 μm.

  When the back surface protective film for solar cells of the present invention is a film composed of a first resin layer, a second resin layer, and a third resin layer, the combination of the thicknesses of the respective layers is preferably 5 to 500 μm, 10 to 990 μm, and It is 5-500 micrometers, More preferably, it is 10-400 micrometers, 20-500 micrometers, and 10-400 micrometers, More preferably, they are 20-350 micrometers, 30-450 micrometers, and 20-350 micrometers.

  When the back surface protective film for solar cells of the present invention is a film comprising a first resin layer, a second resin layer, a third resin layer, and a water vapor barrier layer, the combination of the thicknesses of the respective layers is preferably 5 to 500 μm, 10 to 985 μm, 5 to 500 μm and 5 to 300 μm, more preferably 10 to 400 μm, 20 to 500 μm, 10 to 400 μm and 8 to 250 μm, still more preferably 20 to 350 μm, 30 to 450 μm, 20 to 350 μm and 10 to 200 μm. is there.

  When the back surface protective film for solar cells of the present invention is a film composed of the first resin layer, the second resin layer, the third resin layer, and the back surface protective layer, the combination of the thicknesses of the respective layers is preferably 5 to 500 μm, 10 to 980 μm, 5 to 500 μm and 10 to 500 μm, more preferably 10 to 400 μm, 20 to 500 μm, 10 to 400 μm and 15 to 400 μm, still more preferably 20 to 350 μm, 30 to 450 μm, 20 to 350 μm and 20 to 300 μm. is there.

  When the back surface protective film for solar cells of the present invention is a film comprising a first resin layer, a second resin layer, a third resin layer, a water vapor barrier layer and a back surface protective layer, the combination of the thicknesses of the respective layers is preferably 5-500 μm, 10-975 μm, 5-500 μm, 5-300 μm and 10-500 μm, more preferably 10-400 μm, 20-500 μm, 10-400 μm, 8-250 μm and 15-400 μm, more preferably 20-350 μm, They are 30-450 micrometers, 20-350 micrometers, 10-200 micrometers, and 20-300 micrometers.

  When the back surface protective film for solar cells of the present invention is a film comprising a first resin layer, a second resin layer, and a third resin layer, the production method thereof is a constituent material of each layer, that is, each thermoplastic resin composition. And is not particularly limited. Preferred production methods include co-extrusion using each thermoplastic resin composition (T-die casting method, etc.), and three types of resin films produced using each thermoplastic resin composition are heat-sealed or dry-laminated. And a method of joining with an adhesive.

The back protective film for solar cells of the present invention is a film comprising a first resin layer, a second resin layer, a third resin layer and a water vapor barrier layer, or a first resin layer, a second resin layer, a third resin layer, and In the case of a film comprising a back surface protective layer, the production method thereof is selected according to the layer configuration, the constituent material of each layer, etc., and is not particularly limited. The manufacturing method is exemplified below.
(1) A laminated film is produced by a coextrusion method using the first thermoplastic resin composition, the second thermoplastic resin composition, and the third thermoplastic resin composition, and then the third resin layer in the laminated film. (2) 1st thermoplastic resin composition, 2nd thermoplastic resin composition which joins the surface of this, and the film for water vapor | steam barrier layer formation, or the film for back surface protective layer formation by heat sealing | fusion or dry lamination, or an adhesive agent The laminated film is produced by a coextrusion method using the product and the third thermoplastic resin composition, and then the surface of the third resin layer in the laminated film and the water vapor barrier layer forming film are heat-sealed or A water vapor barrier layer is formed by bonding with dry lamination or an adhesive, and then a back surface protective layer is formed on the surface of the water vapor barrier layer using the fourth thermoplastic resin composition. Method of forming (3) Using the first thermoplastic resin composition, the second thermoplastic resin composition, and the third thermoplastic resin composition, a laminated film is produced as described above, and then in this laminated film The surface of the third resin layer and the film for forming the water vapor barrier layer were bonded by heat fusion, dry lamination or an adhesive to form the water vapor barrier layer, and then separately prepared on the surface of the water vapor barrier layer. , A method of joining a film (film for forming a back surface protective layer) using the fourth thermoplastic resin composition by heat fusion, dry lamination or an adhesive (4) a film for forming a back surface protective layer and a water vapor barrier layer The film for forming is bonded with heat fusion, dry lamination or adhesive to form a laminated film, and then a water vapor barrier layer The surface and the separately prepared third thermoplastic resin composition in the laminated film using the first thermoplastic resin composition, the second thermoplastic resin composition, and the third thermoplastic resin composition are thermally fused or dried. Method of joining by lamination or adhesive

The solar cell module of the present invention is provided with the solar cell back surface protective film of the present invention. A schematic diagram of the solar cell module of the present invention is shown in FIG.
The solar cell module 2 in FIG. 3 includes, from the sunlight receiving surface side (upper side in the drawing), the front surface side transparent protective member 21, the front surface side sealing film (front surface side filler portion) 23, the solar cell element 25, and the back surface side. The sealing film (back surface side filler material portion) 27 and the solar cell back surface protective film 1 of the present invention may be disposed in this order.

As the said surface side transparent protection member 21, what consists of a material excellent in water vapor | steam barrier property is preferable, and the transparent substrate which consists of glass, resin, etc. is used normally. In addition, although glass is excellent in transparency and weather resistance, since impact resistance is not enough and it is heavy, when it is set as the solar cell mounted on the roof of a house, it is preferable to use a weather resistant transparent resin. Examples of the transparent resin include a fluorine-based resin.
The thickness of the surface side transparent protective member 21 is usually about 1 to 5 mm when glass is used, and is usually about 0.1 to 5 mm when transparent resin is used.

The solar cell element 25 has a power generation function by receiving sunlight. As such a solar cell element, if it has a function as a photovoltaic power, it will not be specifically limited, A well-known thing can be used. For example, a crystalline silicon solar cell element such as a single crystal silicon type solar cell element or a polycrystalline silicon type solar cell element; an amorphous silicon solar cell element composed of a single bond type or a tandem structure type; gallium arsenide (GaAs) or indium phosphorus ( III-V compound semiconductor solar cell elements such as InP); II-VI compound semiconductor solar cell elements such as cadmium tellurium (CdTe) and copper indium selenide (CuInSe ₂ ). Of these, a crystalline silicon solar cell element is preferable, and a polycrystalline silicon solar cell element is particularly preferable. A thin film polycrystalline silicon solar cell element, a thin film microcrystalline silicon solar cell element, a hybrid element of a thin film crystalline silicon solar cell element and an amorphous silicon solar cell element, or the like can be used.

  Although not shown in FIG. 3, the solar cell element 25 usually includes a wiring electrode and a take-out electrode. The wiring electrode has an action of collecting electrons generated in the plurality of solar cell elements by receiving sunlight, for example, a solar cell element on the surface side sealing film (surface side filler part) 21 side, It connects so that the solar cell element by the side of the back surface side sealing film (back surface side filler material part) 27 side may be connected. The take-out electrode has an action of taking out electrons collected by the wiring electrode or the like as a current.

The front-side sealing film (front-side filler part) 21 and the back-side sealing film (back-side filler part) 27 (hereinafter collectively referred to as “sealing film”) are usually the same as each other. Alternatively, after using a different sealing film forming material to form a sheet-shaped or film-shaped sealing film in advance, between the surface-side transparent protective member 21 and the solar cell back surface protective film 1, the solar cell element 25, etc. Formed by thermocompression bonding.
The thickness of each sealing film (filler part) is usually about 100 μm to 4 mm, preferably about 200 μm to 3 mm, more preferably about 300 μm to 2 mm. If the thickness is too thin, the solar cell element 25 may be damaged. On the other hand, if the thickness is too thick, the manufacturing cost increases, which is not preferable.

  The sealing film forming material is usually a resin composition or a rubber composition. Examples of the resin include an olefin resin, an epoxy resin, a polyvinyl butyral resin, and the like. Examples of the rubber include silicone rubber and hydrogenated conjugated diene rubber. Of these, olefin resins and hydrogenated conjugated diene rubbers are preferred.

  Examples of olefin resins include olefins such as ethylene, propylene, butadiene, and isoprene, or polymers obtained by polymerizing diolefins, and ethylene and other monomers such as vinyl acetate and acrylate esters. Copolymers, ionomers and the like can be used. Specific examples include polyethylene, polypropylene, polymethylpentene, ethylene / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, ethylene / (meth) acrylic acid ester copolymer, ethylene / vinyl alcohol copolymer, chlorine. Examples thereof include chlorinated polyethylene and chlorinated polypropylene. Among these, an ethylene / vinyl acetate copolymer and an ethylene / (meth) acrylic acid ester copolymer are preferable, and an ethylene / vinyl acetate copolymer is particularly preferable.

  Examples of hydrogenated conjugated diene rubber include hydrogenated styrene / butadiene rubber, styrene / ethylene butylene / olefin crystal block polymer, olefin crystal / ethylene butylene / olefin crystal block polymer, styrene / ethylene butylene / styrene block polymer, and the like. It is done. Preferably, a hydrogenated conjugated diene block copolymer having the following structure, that is, a polymer block A containing an aromatic vinyl compound unit; a conjugated diene compound having a 1,2-vinyl bond content exceeding 25 mol% Polymer block B formed by hydrogenating 80 mol% or more of a double bond portion of a polymer containing a unit; Double of a polymer containing a conjugated diene compound unit having a 1,2-vinyl bond content of 25 mol% or less Polymer block C obtained by hydrogenating 80 mol% or more of the bonded portion; and a polymer block C obtained by hydrogenating 80 mol% or more of the double bond portion of the copolymer containing the aromatic vinyl compound unit and the conjugated diene compound unit. It is a block copolymer having at least two selected from the combined block D.

The sealing film-forming material may contain a crosslinking agent, a crosslinking aid, a silane coupling agent, an ultraviolet absorber, a hindered phenol-based or phosphite-based antioxidant, a hindered amine-based light stabilizer, a light as necessary. Additives such as diffusing agents, flame retardants, and anti-discoloring agents can be contained.
As described above, the material forming the front surface side sealing film (front surface side filler part) 23 and the material forming the back surface side sealing film (back surface side filler part) 27 are the same or different. However, the same is preferable from the viewpoint of adhesiveness.

The solar cell module of the present invention, for example, after arranging the surface side transparent protective member, the surface side sealing film, the solar cell element, the back surface side sealing film and the solar cell back surface protective film of the present invention in this order, These can be manufactured in a laminated state by a lamination method or the like in which heat bonding is performed while vacuum suction is performed.
The lamination temperature in this lamination method is usually about 100 ° C. to 250 ° C. from the viewpoint of adhesion of the solar cell back surface protective film of the present invention. The laminating time is usually about 3 to 30 minutes.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded. In the following, “part” and “%” are based on mass unless otherwise specified.

1. Evaluation method Measurement methods for various evaluation items are shown below.
1-1. Rubber content in thermoplastic resin Calculated from the composition at the time of raw material charging.
1-2. N-phenylmaleimide unit amount and silicon-containing structural unit amount in the thermoplastic resin.
1-3. Glass transition temperature (Tg)
Based on JIS K 7121, it was measured with a differential scanning calorimeter “DSC2910” (model name) manufactured by TA Instruments.

1-4. Peel strength The back protective film for solar cells was cut into strips (length 200 mm, width 15 mm, thickness described in the table) to obtain two evaluation films. A film “Ultra Pearl” (trade name, manufactured by Sanvic Co., Ltd.) having a length of 100 mm, a width of 15 mm and a thickness of 400 μm made of an ethylene / vinyl acetate copolymer is located between the first resin layers in the two evaluation films. And placed in a laminator in a laminated state. Thereafter, the upper and lower portions of the laminator were evacuated and preheated at 150 ° C. for 5 minutes. Next, the upper part was returned to atmospheric pressure and pressed for 15 minutes to obtain a sample for measuring peel strength.
In the obtained peel strength measurement sample, the peel strength was measured by peeling the T-shape from the portion where the evaluation film was not adhered to the EVA film. Moreover, the peeling state was evaluated. The peeled state was “◯” when the EVA film was broken, and “X” when broken at the interface between the EVA film and the evaluation film part.

1-5. L value Solar cell back surface protective film (50 mm x 50 mm, thickness is listed in the table) as a measurement sample, using a spectrophotometer "TCS-II" (model name) manufactured by Toyo Seiki Seisakusho Co., Ltd. L value of the 1st resin layer surface in a protective film was measured.

1-6. Reflectance (%) for light having a wavelength of 400 to 1,400 nm and light having a wavelength of 800 to 1,400 nm
Using a solar cell back surface protective film (50 mm x 50 mm, thickness shown in the table) as a measurement sample, the reflectance was measured with an ultraviolet-visible near-infrared spectrophotometer "V-670" (model name) manufactured by JASCO Corporation. did. That is, light was emitted to the surface of the first resin layer of the measurement sample, the reflectance in the wavelength region from 400 nm or 800 nm to 1,400 nm was measured every 20 nm, and the average value thereof was calculated.

1-7. Transmittance (%) for light with a wavelength of 800 to 1,400 nm
A first resin layer film (50 mm × 50 mm, thickness shown in the table) obtained using the first thermoplastic resin composition containing an infrared transmitting colorant (perylene-based black pigment) is used as a measurement sample. The transmittance was measured with a spectrophotometer “V-670” (model name). That is, light was emitted to the measurement sample, the transmittance in the wavelength region from 800 nm to 1,400 nm was measured every 20 nm, and the average value thereof was calculated.

1-8. Absorptivity (%) for light having a wavelength of 400 to 700 nm
A first resin layer film (50 mm × 50 mm, thickness shown in the table) obtained using the first thermoplastic resin composition containing an infrared transmitting colorant (perylene-based black pigment) is used as a measurement sample. Transmittance and reflectance were measured with a spectrophotometer “V-670” (model name). That is, light was emitted to the measurement sample, the transmittance and reflectance in the wavelength range from 400 nm to 700 nm were measured every 20 nm, and the average value thereof was calculated. The absorptance was calculated by the following formula using the average value of transmittance and the average value of reflectance.
Absorptivity (%) = 100− {transmittance (%) + reflectance (%)}

＜曝露試験＞
太陽電池用裏面保護フィルムを短冊状（長さ２００ｍｍ、幅１５ｍｍ、厚さは表に記載）に裁断し、温度８５℃及び湿度８５％ＲＨの条件下、２，０００時間放置した。 1-9. Tensile strength retention (wet heat aging test)
The solar cell back surface protective film of a predetermined size was subjected to the following exposure test, and the tensile strength before and after exposure was measured according to JIS K7127, and the ratio was calculated.

<Exposure test>
The back protective film for solar cells was cut into strips (length 200 mm, width 15 mm, thickness described in the table) and allowed to stand for 2,000 hours under conditions of a temperature of 85 ° C. and a humidity of 85% RH.

算出値から、寸法安定性を、下記基準により判定した。
○：寸法変化率が１％未満である
△：寸法変化率が１％以上２％未満である
×：寸法変化率が２％以上である
＜加熱試験＞
太陽電池用裏面保護フィルムを正方形状（１２０ｍｍ×１２０ｍｍ）に裁断し、中央部に１００ｍｍ×１００ｍｍの正方形の標線を引いた。このフィルムを、温度１２０℃の恒温槽に３０分間放置した後、取り出して放冷した。 1-10. Dimensional stability The back surface protective film for a solar cell having a predetermined size was subjected to the following heating test, the length of the marked line before and after heating was measured, and the dimensional change rate was calculated based on the following formula.

From the calculated value, the dimensional stability was determined according to the following criteria.
◯: Dimensional change rate is less than 1% Δ: Dimensional change rate is 1% or more and less than 2% ×: Dimensional change rate is 2% or more <Heating test>
The back surface protective film for solar cells was cut into a square shape (120 mm × 120 mm), and a square marked line of 100 mm × 100 mm was drawn at the center. The film was left in a constant temperature bath at a temperature of 120 ° C. for 30 minutes, then taken out and allowed to cool.

1-11. Scratch resistance The surface on the back surface protective layer side of the back surface protective film for solar cells was subjected to 500 reciprocating frictions with a cotton canvas kinkin No. 3 and a vertical load of 500 g using a reciprocating friction tester manufactured by Tohken Precision Industry Co., Ltd. The subsequent surface was visually observed and judged according to the following criteria.
○: No scratch was observed Δ: Scratch was slightly observed ×: Scratch was clearly observed

1-12. Water vapor barrier property Water vapor permeability is measured according to JIS K7129B using MOPER's water vapor permeability measuring device “PERMATRAN W3 / 31” (model name) under conditions of a temperature of 40 ° C. and a humidity of 90% RH. did. As the transmission surface, the surface that is not the first resin layer was disposed on the water vapor side.

1-13. Photoelectric conversion efficiency improvement rate In a room adjusted to a temperature of 25 ° C. ± 2 ° C. and a humidity of 50 ± 5% RH, a cell is previously used by using Solar Simulator “PEC-11” (model name) manufactured by Pexel Technologies. A glass cell with a thickness of 3 mm is placed on the surface of a ¼ polycrystalline silicon cell whose photoelectric conversion efficiency is measured, and a back surface protective film for a solar cell is placed on the back surface. The silicon cell is sandwiched between the glass and the solar cell. EVA was introduced between the back surface protective films to seal the silicon cells, thereby producing solar cell modules. Then, in order to reduce the influence of temperature, the photoelectric conversion efficiency was measured immediately after the light irradiation. The photoelectric conversion efficiency improvement rate was calculated | required using the obtained photoelectric conversion efficiency and the photoelectric conversion efficiency of the cell single-piece | unit.
Photoelectric conversion efficiency improvement rate (%) = {(photoelectric conversion efficiency of module−photoelectric conversion efficiency of single cell) ÷ (photoelectric conversion efficiency of single cell)} × 100

2. Raw materials used for preparation of thermoplastic resin composition, etc., are shown below.

2-1. Graft polymerization resin (A-1)
1.3 parts of p-vinylphenylmethyldimethoxysilane and 98.7 parts of octamethylcyclotetrasiloxane are mixed, and this is put into 300 parts of distilled water in which 2.0 parts of dodecylbenzenesulfonic acid is dissolved, and 3 parts by a homogenizer. The mixture was stirred and dispersed for emulsification. This emulsified dispersion was transferred to a separable flask equipped with a condenser, a nitrogen inlet and a stirrer, and heated at 90 ° C. for 6 hours while stirring. Subsequently, it was kept at 5 ° C. for 24 hours to complete the condensation, and a latex containing a polyorganosiloxane rubber (silicon-containing rubber) was obtained. The condensation rate was 93%. Thereafter, the latex was neutralized to pH 7 using an aqueous sodium carbonate solution. The obtained polyorganosiloxane rubber had a volume average particle size of 300 nm.
Next, in a 7-liter glass flask equipped with a stirrer, 100 parts of ion exchange water, 1.5 parts of potassium oleate, 0.01 parts of potassium hydroxide, 0.1 part of tert-dodecyl mercaptan, A batch polymerization component consisting of a latex adjusted to pH 7 containing 40 parts of an organosiloxane rubber, 15 parts of styrene and 5 parts of acrylonitrile was added, and the temperature was raised while stirring. When the temperature reaches 45 ° C., the activity comprises 0.1 part of sodium ethylenediaminetetraacetate, 0.003 part of ferrous sulfate, 0.2 part of sodium formaldehyde sulfoxylate dihydrate and 15 parts of ion-exchanged water. Aqueous agent aqueous solution and 0.1 part of diisopropylbenzene hydroperoxide were added and polymerization was carried out for 1 hour.
Thereafter, 50 parts of ion exchange water, 1 part of potassium oleate, 0.02 part of potassium hydroxide, 0.1 part of tert-dodecyl mercaptan, 0.2 part of diisopropylbenzene hydroperoxide, 30 parts of styrene and An incremental polymerization component consisting of 10 parts of acrylonitrile was added continuously over 3 hours to continue the polymerization. After completion of the addition, stirring was further continued. After 1 hour, 0.2 part of 2,2′-methylenebis (4-ethyl-6-tert-butylphenol) was added to complete the polymerization, and a latex containing the graft polymerization resin (A-1) was obtained. Next, 1.5 parts of sulfuric acid is added to the latex to coagulate the resin component at 90 ° C., and then the resin component is washed with water, dehydrated and dried to obtain a powdered graft polymerization resin (A-1). Obtained. The glass transition temperature (Tg) was 108 ° C., the graft ratio was 84%, and the intrinsic viscosity [η] (in methyl ethyl ketone, 30 ° C.) was 0.60 dl / g.

2-2. Graft polymerization resin (A-2)
Accommodates latex with a solid content concentration of 40% containing 50 parts of acrylic rubber (gel content 90%) with a volume average particle size of 100 nm, obtained by emulsion polymerization of 99 parts of n-butyl acrylate and 1 part of allyl methacrylate. 1 part of sodium dodecylbenzenesulfonate and 150 parts of ion-exchanged water were added to the reactor and diluted. Thereafter, the inside of the reactor was replaced with nitrogen gas, and 0.02 part of disodium ethylenediaminetetraacetate, 0.005 part of ferrous sulfate and 0.3 part of sodium formaldehydesulfoxylate were added, and the mixture was stirred up to 60 ° C. The temperature rose.
On the other hand, in a separately prepared container, 1.0 part of terpinolene and 0.2 part of cumene hydroperoxide were dissolved in 50 parts of a mixture of 37.5 parts of styrene and 12.5 parts of acrylonitrile. To obtain a monomer composition.
Next, polymerization was performed at 70 ° C. while adding the monomer composition to the reactor at a constant flow rate over 5 hours to obtain a latex containing a graft polymerization resin (A-2). Magnesium sulfate was added to this latex to coagulate the resin component. Thereafter, the resin component was washed with water, dehydrated and dried to obtain a powdered graft polymerization resin (A-2). The glass transition temperature (Tg) was 108 ° C., the graft ratio was 93%, and the intrinsic viscosity [η] (in methyl ethyl ketone, 30 ° C.) was 0.30 dl / g.

2-3. Graft polymerization resin (A-3)
50 parts of acrylic rubber (gel content 90%) obtained by emulsion polymerization of 97.5 parts of n-butyl acrylate, 1 part of allyl methacrylate and 1.5 parts of vinylmethoxysilane 1 part of sodium dodecylbenzenesulfonate and 150 parts of ion-exchanged water were added to a reactor containing a latex containing 40% solid content and diluted. Thereafter, the inside of the reactor was replaced with nitrogen gas, and 0.02 part of disodium ethylenediaminetetraacetate, 0.005 part of ferrous sulfate and 0.3 part of sodium formaldehydesulfoxylate were added, and the mixture was stirred up to 60 ° C. The temperature rose.
On the other hand, in a separately prepared container, 1.0 part of terpinolene and 0.2 part of cumene hydroperoxide were dissolved in 50 parts of a mixture of 37.5 parts of styrene and 12.5 parts of acrylonitrile. To obtain a monomer composition.
Next, polymerization was performed at 70 ° C. while adding the monomer composition to the reactor at a constant flow rate over 5 hours to obtain a latex containing a graft polymerization resin (A-3). Magnesium sulfate was added to this latex to coagulate the resin component. Thereafter, the resin component was washed with water, dehydrated and dried to obtain a powdered graft polymerization resin (A-3). The glass transition temperature (Tg) was 108 ° C., the graft ratio was 93%, and the intrinsic viscosity [η] (in methyl ethyl ketone, 30 ° C.) was 0.30 dl / g.

2-4. Graft polymerization resin (A-4)
In a glass reaction vessel equipped with a stirrer, 75 parts of ion-exchanged water, 0.5 part of potassium rosinate, 0.1 part of tert-dodecyl mercaptan, volume average particle diameter of 270 nm polybutadiene rubber (gel content: 90%) Latex having a solid content concentration of 57% containing 32 parts, Styrene-butadiene copolymer having a volume average particle size of 550 nm (styrene unit content 25%, gel content 50%) Latex having a solid content concentration of 68%, styrene 15 parts and 5 parts of acrylonitrile were added, and it heated up, stirring in nitrogen stream. When the internal temperature reached 45 ° C., an aqueous solution in which 0.2 parts of sodium pyrophosphate, 0.01 parts of ferrous sulfate heptahydrate and 0.2 parts of glucose were dissolved in 20 parts of ion-exchanged water was added. . Thereafter, 0.07 part of cumene hydroperoxide was added, polymerization was started at 70 ° C., and polymerization was performed for 1 hour.
Thereafter, 50 parts of ion exchange water, 0.7 part of potassium rosinate, 30 parts of styrene, 10 parts of acrylonitrile, 0.05 part of tert-dodecyl mercaptan and 0.01 part of cumene hydroperoxide are continuously added over 3 hours. The polymerization was continued. After polymerizing for 1 hour, 0.2 part of 2,2′-methylene-bis (4-ethylene-6-tert-butylphenol) was added to complete the polymerization to obtain a latex.
Next, magnesium sulfate was added to the latex to coagulate the resin component. Then, the graft polymerization resin (A-4) was obtained by washing with water and drying. The graft ratio was 72%, and the intrinsic viscosity [η] of the acetone-soluble component was 0.47 dl / g. The glass transition temperature (Tg) was 108 ° C.

2-5. Acrylonitrile / styrene copolymer AS resin “SAN-H” (trade name) manufactured by Technopolymer Co., Ltd. was used. The glass transition temperature (Tg) is 108 ° C.

2-6. Acrylonitrile / styrene / N-phenylmaleimide copolymer Acrylonitrile / styrene / N-phenylmaleimide copolymer “Polyimilex PAS1460” (trade name) manufactured by Nippon Shokubai Co., Ltd. was used. The amount of N-phenylmaleimide units is 40%, the amount of styrene units is 51%, and the Mw in terms of polystyrene by GPC is 120,000. The glass transition temperature (Tg) is 173 ° C.

2-7. White colorant Titanium oxide “Taipeku CR-50-2” (trade name) manufactured by Ishihara Sangyo Co., Ltd. was used. The average primary particle size is 0.25 μm.

2-8. Infrared transmitting colorant A perylene-based black pigment “Lumogen BLACK FK4280” (trade name) manufactured by BASF was used.

2-9. Yellow colorant A quinophthalone yellow pigment “Pariotol Yellow K0961HD” (trade name) manufactured by BASF was used.

2-10. Water vapor barrier layer forming film (R-1)
A transparent vapor deposition film “Tech Barrier AX” (trade name) manufactured by Mitsubishi Plastics, Inc. was used. It is a transparent film having a silica vapor deposition film on one side of a PET film, and has a thickness of 12 μm and a water vapor transmission rate (JIS K7129) of 0.15 g / (m ² · day).
2-11. Water vapor barrier layer forming film (R-2)
An inorganic binary vapor barrier film “Ecosia VE500” (trade name) manufactured by Toyobo Co., Ltd. was used. This is a transparent film obtained by vapor-depositing (silica / alumina) on one side of a PET film, and has a thickness of 12 μm and a water vapor permeability of 0.5 g / (m ² · day).

2-12. Back surface protective layer forming film (P-1)
A translucent PET film “Lumirror X10S” (trade name) manufactured by Toray Industries, Inc. was used. The thickness is 50 μm.
2-13. Back surface protective layer forming film (P-2)
A milk white PET film “Melinex 238” (trade name) manufactured by Teijin DuPont was used. The thickness is 75 μm.

3. Manufacture and evaluation of back surface protection film for solar cells (1)
Example 1-1
The raw materials of the thermoplastic resin composition for forming the first resin layer, the second resin layer, and the third resin layer shown in Table 1 were mixed with a Henschel mixer. Thereafter, using a twin screw extruder (model name “TEX44”, manufactured by Nippon Steel Works), melt kneading is performed at a barrel temperature of 270 ° C., and the first thermoplastic resin composition, the second thermoplastic resin composition, and the third heat. Three types of pellets of the plastic resin composition were obtained.
Next, the first thermoplastic resin composition is used in each extruder using a multilayer film forming machine having a T die having a die width of 1,400 mm and a lip interval of 1.5 mm and including three extruders having a screw diameter of 65 mm. The 2nd thermoplastic resin composition and the 3rd thermoplastic resin composition were supplied. Then, the molten resin was discharged from the T die at a melting temperature of 270 ° C. to obtain a three-layer soft film. Thereafter, this three-layer soft film was brought into surface contact with a cast roll whose surface temperature was controlled at 95 ° C. with an air knife, cooled and solidified, and a white three-layer solar cell back surface protective film having a thickness of 170 μm was obtained. Obtained. The thicknesses of the first resin layer, the second resin layer, and the third resin layer are as shown in Table 1. Thickness gauge (model name “ID-C1112C”, manufactured by Mitutoyo Co., Ltd.) was used to cut the film after 1 hour from the start of film production. Then, the thickness was measured at intervals of 10 mm (n = 107), and the average value was obtained. Measurement point values in the range of 20 mm from the edge of the film were removed from the average calculation.
Various evaluations were performed on the solar cell back surface protective film, and the results are also shown in Table 1.

Examples 1-2 to 1-3 and Comparative Example 1-1
Using the raw material of the thermoplastic resin composition for forming the first resin layer, the second resin layer, and the third resin layer shown in Table 1, in the same manner as in Example 1-1, a white three-layer type The back surface protective film for solar cells was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 1.

4). Manufacture and evaluation of back surface protection film for solar cells (2)
Examples 1-4 to 1-5 and Comparative Example 1-2
Using the thermoplastic resin composition for forming the first resin layer, the second resin layer, and the third resin layer shown in Table 2, as in Example 1-1, the back surface for the three-layer solar cell A protective film was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 2.

As is clear from Table 1 and Table 2, the back surface protection for solar cells comprising a first resin layer formed using a thermoplastic resin composition containing a graft polymerization resin (A-2) that is not a silicon-containing thermoplastic resin. Comparative Example 1-1 and Comparative Example 1-2, which were films, had low peel strengths of 12 N and 15 N, respectively, and adhesion was not sufficient in bonding with a film made of an ethylene / vinyl acetate copolymer. .
On the other hand, Examples 1-1 to 1-5, which are back surface protective films for solar cells including a first resin layer formed using a thermoplastic resin composition containing a silicon-containing thermoplastic resin, have a peel strength of 67. It was as high as ˜82 N and excellent in adhesiveness.

5). Manufacture and evaluation of back surface protection film for solar cells (3)
Example 2-1
The first thermoplasticity shown in Table 3 was used for each extruder using a multilayer film molding machine having a T-die having a die width of 1,400 mm and a lip interval of 1.5 mm and having three extruders with a screw diameter of 65 mm. A resin composition, a second thermoplastic resin composition, and a third thermoplastic resin composition were supplied. Then, each resin composition melted at a temperature of 270 ° C. was discharged from the T die to obtain a three-layer soft film. Thereafter, this three-layer soft film was cooled and solidified with an air knife while being in close contact with a cast roll whose surface temperature was controlled to 95 ° C., to obtain a laminated film having a thickness of 170 μm. The thicknesses of the first resin layer, the second resin layer, and the third resin layer are as shown in Table 3. Thickness gauge "ID-C1112C" (model name) manufactured by Mitutoyo Co., Ltd. is used to cut the film after 1 hour from the start of film production. Then, the thickness was measured at intervals of 10 mm (n = 107), and the average value was obtained. Measurement point values in the range of 20 mm from the edge of the film were removed from the average calculation.
Next, the water vapor barrier layer forming film (R-1) is adhered to the outer surface of the third resin layer in the laminated film using a polyurethane-based adhesive so that the vapor deposition film becomes the outer surface. The back surface protective film for solar cells was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 3. FIG.

Example 2-2
Using the first thermoplastic resin composition, the second thermoplastic resin composition, the third thermoplastic resin composition, and the water vapor barrier layer forming film (R-2) shown in Table 3, Example 2- In the same manner as in Example 1, a solar cell back surface protective film was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 3. FIG.

Example 2-3
Using a multilayer film forming machine having a T-die having a die width of 1,400 mm and a lip interval of 1.5 mm and having three extruders with a screw diameter of 65 mm, the first thermoplasticity shown in Table 4 is used for each extruder. A resin composition, a second thermoplastic resin composition, and a third thermoplastic resin composition were supplied. Then, each resin composition melted at a temperature of 270 ° C. was discharged from the T die to obtain a three-layer soft film. Thereafter, this three-layer soft film was cooled and solidified with an air knife while being in close contact with a cast roll whose surface temperature was controlled to 95 ° C., to obtain a laminated film having a thickness of 170 μm. The thicknesses of the first resin layer, the second resin layer, and the third resin layer are as shown in Table 4. Thickness gauge "ID-C1112C" (model name) manufactured by Mitutoyo Co., Ltd. is used to cut the film after 1 hour from the start of film production. Then, the thickness was measured at intervals of 10 mm (n = 107), and the average value was obtained. Measurement point values in the range of 20 mm from the edge of the film were removed from the average calculation.
Next, the back surface protective layer-forming film (P-1) is adhered to the outer surface of the third resin layer in the laminated film using a polyurethane-based adhesive so that the deposited film becomes the outer surface. The back surface protective film for solar cells was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 4.

Example 2-4
Using the first thermoplastic resin composition, the second thermoplastic resin composition, the third thermoplastic resin composition, and the back protective layer forming film (P-2) shown in Table 4, Example 2-3 and Similarly, the back surface protective film for solar cells was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 4.

Example 2-5
Using a multilayer film molding machine having a T-die having a die width of 1,400 mm and a lip interval of 1.5 mm, and having three extruders with a screw diameter of 65 mm, the first thermoplastic resin composition, the second A thermoplastic resin composition and a third thermoplastic resin composition were supplied. Then, each resin composition melted at a temperature of 270 ° C. was discharged from the T die to obtain a three-layer soft film. Thereafter, this three-layer soft film was cooled and solidified with an air knife while being in close contact with a cast roll whose surface temperature was controlled to 95 ° C., to obtain a laminated film having a thickness of 170 μm. The thicknesses of the first resin layer, the second resin layer, and the third resin layer are as shown in Table 4. Thickness gauge "ID-C1112C" (model name) manufactured by Mitutoyo Co., Ltd. is used to cut the film after 1 hour from the start of film production. Then, the thickness was measured at intervals of 10 mm (n = 107), and the average value was obtained. Measurement point values in the range of 20 mm from the edge of the film were removed from the average calculation.
Next, the water vapor barrier layer forming film (R-1) is adhered to the outer surface of the third resin layer in the laminated film using a polyurethane-based adhesive so that the vapor deposition film becomes the outer surface. It was. Furthermore, the back surface protective layer forming film (P-1) was adhered to the surface of the vapor deposition film in the water vapor barrier layer using a polyurethane-based adhesive to obtain a back surface protective film for a solar cell. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 4.

Comparative Example 2-1
Except having used the 1st thermoplastic resin composition which has a composition shown in Table 4, it carried out similarly to Example 2-5, and obtained the back surface protective film for solar cells. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 4.

Example 2-6
Using the first thermoplastic resin composition, the second thermoplastic resin composition, the third thermoplastic resin composition, and the water vapor barrier layer forming film (R-1) shown in Table 5, Example 2- In the same manner as in Example 1, a solar cell back surface protective film was obtained. And about this back surface protective film for solar cells, various evaluation was performed and the result was written together in Table 5.

Example 2-7
Using the first thermoplastic resin composition, the second thermoplastic resin composition, the third thermoplastic resin composition, and the back protective layer forming film (P-1) shown in Table 6, Example 2- In the same manner as in No. 3, a solar cell back surface protective film was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 6.

Example 2-8
The first thermoplastic resin composition, the second thermoplastic resin composition, the third thermoplastic resin composition, the water vapor barrier layer forming film (R-1), and the back surface protective layer forming film shown in Table 6 Using (P-1), a back surface protective film for a solar cell was obtained in the same manner as Example 2-5. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 6.

Comparative Example 2-2
Except having used the 1st thermoplastic resin composition which has a composition shown in Table 6, it carried out similarly to Example 2-8, and obtained the back surface protective film for solar cells. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 6.

  The back surface protective film for solar cell of the present invention is bonded to a filler part containing an ethylene / vinyl acetate copolymer composition, etc., which embeds a solar cell element constituting the solar cell module in the first resin layer. It has excellent heat resistance, flexibility, weather resistance, light reflectivity or design, and is flexible as well as a solar cell module that constitutes a solar cell used for the roof of a house. It is useful as a member for protecting the back surface of a solar cell module having a property.

1, 1A and 1B: Solar cell back surface protective film 11: First resin layer 12: Second resin layer 13: Third resin layer 14: Other layers (water vapor barrier layer)
15: Other layers (back surface protective layer)
2: Solar cell module 21: Front side transparent protective member 23: Front side sealing film 25: Solar cell element 27: Back side sealing film

Claims (10)

  A solar cell back surface protective film comprising a first resin layer, a second resin layer, and a third resin layer in order, wherein the first resin layer contains a silicon-containing thermoplastic resin. Protective film.   2. The solar cell according to claim 1, wherein when light having a wavelength of 400 to 1,400 nm is radiated to the surface of the first resin layer in the solar cell back surface protective film, the reflectance with respect to the light is 50% or more. Back protection film.   The back surface protection film for solar cells according to claim 1 or 2, wherein at least one of the first resin layer, the second resin layer, and the third resin layer contains a white colorant.   In the first resin layer, the transmittance for light with a wavelength of 800 to 1,400 nm is 60% or more, the absorptance for light with a wavelength of 400 to 700 nm is 60% or more, and the wavelength is 800 to 1,400 nm. The back surface protective film for solar cells according to claim 1, wherein when light is radiated to the surface of the first resin layer in the back surface protective film for solar cells, the reflectance with respect to the light is 50% or more.   The back surface protection film for solar cells according to claim 1 or 4, wherein the first resin layer contains an infrared transmitting colorant, and the second resin layer and / or the third resin layer contains a white colorant. .   Furthermore, the back surface protective film for solar cells in any one of Claims 1 thru | or 5 provided with a water vapor | steam barrier layer and / or a back surface protective layer in the outer surface of the said 3rd resin layer.   7. The solar cell according to claim 1, wherein the silicon-containing thermoplastic resin includes a graft polymerization resin obtained by polymerizing a monomer containing an aromatic vinyl compound in the presence of a silicon-containing rubber. Back protection film.   The thermoplastic resin constituting the first resin layer, the thermoplastic resin constituting the second resin layer, and the thermoplastic resin constituting the third resin layer are derived from an aromatic vinyl compound that is the same or different from each other. The back surface protective film for solar cells in any one of Claims 1 thru | or 7 containing the structural unit to do.   The back surface protective film for solar cells according to any one of claims 1 to 8, which has a thickness of 30 to 1,000 µm.   A solar cell module comprising the solar cell back surface protective film according to claim 1.

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