KR102547451B1 - Film for stacking transparent conductive layer, method of manufacturing the same and transparent conductive film - Google Patents

Abstract

(Problem) For lamination of a transparent conductive film that makes it difficult to visually recognize the pattern of the transparent conductive film, can set the resistance value of the transparent conductive film to a desired value, and has excellent workability when forming wiring or the like on the surface of the low refractive index layer. A film and a transparent conductive film produced using the same are provided.
(Solution) A transparent conductive film lamination film (1) comprising a transparent plastic substrate (2) and a low refractive index layer (4) formed on at least one side of the transparent plastic substrate (2), wherein the low refractive index layer ( 4) has a refractive index of 1.30 to 1.50, a surface area increase rate in the low refractive index layer 4 is 5% or less, and a surface free energy of the low refractive index layer 4 is 25.0 to 100 mJ/m 2 ; A film (1) for laminating transparent conductive films, characterized in that the refractive index layer (4) has a thickness of 2 to 70 nm.

Description

Transparent conductive film lamination film, manufacturing method thereof, and transparent conductive film

The present invention relates to a film for lamination of transparent conductive films, a method for producing the film, and a transparent conductive film manufactured using the film.

A touch panel capable of inputting information by directly contacting an image display unit is one in which light-transmitting input devices are disposed on various displays, and representative types include a resistive touch panel and a capacitive touch panel.

In these touch panels, a transparent conductive film in which a transparent conductive film made of tin-doped indium oxide (ITO) or the like is laminated on a transparent plastic substrate may be used.

In a capacitive touch panel, in order to detect the touch position of a finger, after transparent conductive films are laminated, two transparent conductive films patterned in a line are arranged so that the transparent conductive films cross each other to form a lattice shape. In the capacitive touch panel obtained in this way, there are points where the transparent conductive film is laminated and points where the transparent conductive film is not laminated, and the reflectance and transmittance are different depending on the presence or absence of the transparent conductive film. A lattice-like pattern is recognized, and as a result, there is a problem of lowering visibility as a display.

In order to make it difficult to visually recognize this lattice pattern, that is, the portion where the transparent conductive film is laminated, a transparent conductive film formed by sequentially stacking a high refractive index layer, a low refractive index layer and a transparent conductive film on a transparent substrate film (transparent plastic substrate) is proposed. has been done (see Patent Documents 1 and 2).

Patent Document 1: Japanese Unexamined Patent Publication No. 2014-197080 Patent Document 2: Japanese Unexamined Patent Publication No. 2014-119475

In the transparent conductive film described in Patent Document 1, in order to obtain a desired refractive index, a high refractive index layer is formed on a transparent plastic substrate using a composition containing 10 parts by mass of a thermoplastic resin and 12.24 parts by mass of titanium oxide, and 10 parts by mass of titanium oxide is formed thereon. A low refractive index layer is formed using a composition containing a part active energy curable resin and 100 parts by mass of a hollow silica sol (paragraphs 0066, 0069 and 0071 of Patent Document 1). However, in such a transparent conductive film, the resistance value of the transparent conductive film becomes a value higher than desired.

Further, in the transparent conductive film described in Patent Document 2, in order to obtain a desired refractive index, a hard coat layer is formed on a polyethylene terephthalate film using a composition containing 58 parts by mass of a polymerizable monomer and 37 parts by mass of a polymerizable oligomer, , A high refractive index layer is formed using a composition containing a high refractive index resin thereon, and a low refractive index layer is formed thereon using a composition containing 60 parts by mass of a polymerizable monomer and 35 parts by mass of a fluorine-containing compound ( Paragraphs 0113, 0115, 0118 and 0125 to 0126 of Patent Document 2). However, in such a transparent conductive film, when applying silver paste for forming silver wiring or the like on the surface opposite to the high refractive index layer in the low refractive index layer, clumping occurs, or the formed silver wiring has poor adhesion to the surface. this may also decrease. Also, when an adhesive is bonded to the surface of the low refractive index layer, adhesion between the surface and the adhesive becomes insufficient.

The present invention has been made in view of the above reality, and it is possible to make it difficult to visually recognize the pattern of the transparent conductive film, it is possible to set the resistance value of the transparent conductive film to a desired value, and it is possible to form a wiring or the like on the surface of the low refractive index layer. An object of the present invention is to provide a transparent conductive film lamination film having excellent workability, a method for producing the film, and a transparent conductive film produced using the film. In addition, in this specification, the "surface" of a low-refractive-index layer means the surface opposite to the transparent plastic substrate in a low-refractive-index layer or a high-refractive-index layer, unless otherwise specified.

In order to achieve the above object, first, the present invention is a film for laminating a transparent conductive film comprising a transparent plastic substrate and a low refractive index layer formed on at least one side of the transparent plastic substrate, wherein the refractive index of the low refractive index layer is 1.30 to 1.50, and on the surface of the low refractive index layer opposite to the transparent plastic substrate, a square region of 4.992 µm square is arbitrarily selected, and on the surface of the low refractive index layer corresponding to one side of the square. When the product of the surface length on the surface of the side and the surface length on the surface of the low refractive index layer corresponding to the other side orthogonal to the side is the real surface area, the following formula (I)

For laminating a transparent conductive film, characterized in that the surface area increase rate calculated by A film is provided (Invention 1).

In the above invention (invention 1), since the refractive index of the low refractive index layer is sufficiently low, the pattern of the transparent conductive film is difficult to be visually recognized. In addition, since the thickness of the low refractive index layer is not too thick, the invisibleness of the pattern of the transparent conductive film is sufficiently secured. In addition, the smoothness of the surface of the low refractive index layer is sufficiently high, and therefore, when a transparent conductive film is laminated on the surface, the resistance value of the transparent conductive film can be set to a desired value. Further, since the surface free energy of the low refractive index layer is sufficiently high, occurrence of agglomeration when silver paste is applied to the surface of the low refractive index layer is suppressed, and adhesion between the surface and the silver wiring is also sufficient. Moreover, also when bonding an adhesive material to the said surface, the adhesiveness of the said surface and an adhesive material becomes sufficient.

In the above invention (Invention 1), the low refractive index layer does not contain refractive index adjusting particles or contains refractive index adjusting particles in an amount of less than 100 parts by mass based on 100 parts by mass of the matrix resin composition constituting the low refractive index layer. (invention 2).

In the above inventions (Inventions 1 and 2), it is preferable that a high refractive index layer having a refractive index greater than the refractive index of the low refractive index layer is interposed between the transparent plastic substrate and the low refractive index layer (Invention 3).

In the above invention (Invention 3), it is preferable that the refractive index of the high refractive index layer is 1.60 to 1.90 (Invention 4).

Second, the present invention is a method for producing the film for laminating the transparent conductive film (Inventions 1 to 4). When forming the low refractive index layer, after coating the material constituting the low refractive index layer, the temperature is 30 to 70 ° C. (invention 5) a method for producing a film for laminating a transparent conductive film, comprising heat treatment for 10 seconds to 3 minutes.

Thirdly, the present invention is transparent, characterized in that the film for laminating the transparent conductive film (Inventions 1 to 4) and the transparent conductive film laminated on the side opposite to the transparent plastic substrate in the low refractive index layer are provided. A conductive film is provided (Invention 6).

In the above invention (Invention 6), when the transparent conductive film is etched in the transparent conductive film, it is preferable that the absolute value of the difference in reflectance (%) at a wavelength of 400 nm before and after the etching is 9 or less ( invention 7).

According to the present invention, it is possible to make the pattern of the transparent conductive film difficult to visually recognize, the resistance value of the transparent conductive film can be set to a desired value, and the transparent conductive film has excellent processability when forming wiring or the like on the surface of the low refractive index layer. A film for lamination, a method for producing the film, and a transparent conductive film produced using the film are provided.

1 is a cross-sectional view of a film for lamination of a transparent conductive film according to an embodiment of the present invention.
2 is a cross-sectional view of a transparent conductive film according to an embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

[Film for lamination of transparent conductive films]

1 is a cross-sectional view of a film for lamination of a transparent conductive film according to an embodiment of the present invention. The film 1 for laminating a transparent conductive film according to the present embodiment includes a transparent plastic substrate 2, a high refractive index layer 3 laminated on one side (upper side in FIG. 1) of the transparent plastic substrate 2, It consists of the low refractive index layer 4 laminated|stacked on the surface (upper side in FIG. 1) on the opposite side to the transparent plastic substrate 2 in the high refractive index layer 3.

In the film 1 for laminating transparent conductive films according to the present embodiment, the low refractive index layer 4 has a sufficiently low refractive index of 1.30 to 1.50, and the low refractive index layer 4 and the low refractive index layer 4 are laminated. Since the difference in refractive index with and is sufficient, the pattern of the transparent conductive film is difficult to visually recognize. And the thickness of the low-refractive-index layer 4 is 2-70 nm, and the said thickness is not too thick, and the invisibleness of the pattern of a transparent conductive film is fully ensured. In addition, the surface area increase rate of the low refractive index layer 4 is 5% or less, and the smoothness of the surface of the low refractive index layer 4 is sufficiently high. As a result, when a transparent conductive film is laminated on the surface, the resistance of the transparent conductive film You can set the value to any value you want. And, since the surface free energy of the low refractive index layer 4 is sufficiently high, 25.0 to 100.0 mJ/m 2 , even if silver paste or the like is coated on the surface of the low refractive index layer 4, the occurrence of agglomeration is suppressed, and the surface The adhesiveness of the formed silver wiring also becomes sufficient. Moreover, also when bonding an adhesive material to the said surface, the adhesiveness of the said surface and an adhesive material becomes sufficient.

<Low refractive index layer>

The low refractive index layer 4 of the transparent conductive film lamination film 1 according to the present embodiment is a layer having a relatively low refractive index. The refractive index of the low refractive index layer 4 is 1.30 to 1.50, preferably 1.32 to 1.48, particularly preferably 1.34 to 1.47. When the refractive index of the low refractive index layer 4 is within this range, the difference in refractive index between the low refractive index layer 4 and the high refractive index layer 3 on which the low refractive index layer 4 is laminated or the transparent plastic substrate 2 is sufficient. This makes it difficult to visually recognize the pattern of the transparent conductive film. In addition, when the refractive index of the low-refractive-index layer 4 is within the above range, since usable materials and the like are not unnecessarily limited, other properties such as transparency can be improved. In addition, the refractive index in this specification is a value measured as shown in the Example.

The surface of the low refractive index layer 4 of the film for lamination of transparent conductive films 1 according to the present embodiment has relatively high smoothness. Specifically, on the surface opposite to the transparent plastic substrate 2 in the low refractive index layer, a square area of 4.992 µm square is arbitrarily selected, and on the surface of the low refractive index layer corresponding to one side of the square When the product of the surface length on the surface of the side and the surface length on the surface of the low refractive index layer corresponding to the other side orthogonal to the side is the real surface area, the following formula (I)

The surface area increase rate calculated by is 5% or less, preferably 4.8% or less, and particularly preferably 4.6% or less. Moreover, the lower limit of the surface area increase rate is 0%, and the one closer to this value is preferable. Here, the surface length means a length measured by tracing irregularities existing on the surface. The present inventors have found that the resistance value of the transparent conductive film laminated on the surface increases as the smoothness of the surface of the low refractive index layer 4 decreases. In the transparent conductive film lamination film 1 according to the present embodiment, when the surface area increase rate is 5% or less, the smoothness of the surface of the low refractive index layer 4 is sufficiently high, and the transparent conductive film is laminated on the surface. The resistance value of the conductive film is maintained at a low value. Therefore, the resistance value of the transparent conductive film can be set to a desired value by manufacturing a transparent conductive film using the film 1 for lamination of the transparent conductive film according to the present embodiment. In addition, the surface area increase rate in this specification can be measured using a laser microscope etc. which can observe and measure a surface shape, and specific measurement conditions are as showing the test example mentioned later.

In the film 1 for laminating transparent conductive films according to the present embodiment, the surface free energy of the low refractive index layer 4 is 25.0 to 100.0 mJ/m2, preferably 28.0 to 70.0 mJ/m2, particularly 30.0 to 60.0 It is preferably mJ/m 2 . When the surface free energy of the low refractive index layer 4 is 25.0 to 100.0 mJ/m 2 , the workability at the time of forming wiring or the like on the surface of the low refractive index layer 4 is excellent. In addition, the surface free energy in this specification measures the contact angle of various liquid droplets (dispersion component, dipole component, hydrogen bond component) with respect to the surface of the low refractive index layer 4, and based on the value, Kitazaki Hata It was obtained by theory. The contact angle is measured according to JIS R3257 by the static method using a contact angle meter (DM-701 manufactured by Kyowa Interface Science Co., Ltd. in the test example). Specific measurement conditions are as shown in the test examples described later.

The thickness of the low refractive index layer 4 in this embodiment is 2 to 70 nm, preferably 10 to 60 nm, and particularly preferably 20 to 40 nm. When the thickness of the low refractive index layer 4 is 70 nm or less, invisibility of the pattern of the transparent conductive film can be ensured. Moreover, when the thickness of the low-refractive-index layer 4 is 2 nm or more, smoothness of the surface of the low-refractive-index layer 4 can fully be ensured. In addition, the thickness of the low refractive index layer 4 in this specification is a value measured with an ellipsometer, and specific measurement conditions are as showing in the test example mentioned later.

The material constituting the low-refractive-index layer 4 of this embodiment is not particularly limited as long as it satisfies the above physical properties, but the low-refractive-index layer 4 is preferably made of a siloxane compound. As the siloxane compound, inorganic silica-based compounds, polyorganosiloxane-based compounds, and mixtures thereof can be used. Inorganic silica-based compounds include polysilicic acid.

In the case of using a polyorganosiloxane-based compound as the siloxane compound, it is preferable to use one in which less than two methyl groups are bonded to Si atoms from the viewpoint of obtaining a desired surface free energy.

The siloxane compound may be one prepared by a known method, for example, the following general formula (A)

R ¹ _n Si(OR ² ) _4-n ... (A)

(R ¹ is a non-hydrolyzable group, an alkyl group, a substituted alkyl group (as a substituent, a halogen atom, a hydroxyl group, a thiol group, an epoxy group, a (meth)acryloyloxy group, etc.), an alkenyl group, an aryl group, or an aralkyl group; , R ² is a lower alkyl group, and n is an integer of 0 to 3. When a plurality of R ¹ groups and OR ² groups are respectively present, the plurality of R ¹ groups may be the same or different, and the plurality of OR ² groups may be the same or different. .) It may be obtained by partially or completely hydrolyzing the alkoxysilane compound represented by using an inorganic acid such as hydrochloric acid or sulfuric acid or an organic acid such as oxalic acid or acetic acid, followed by polycondensation. During this reaction, an organic solvent may be used for uniform hydrolysis, and an appropriate amount of an aluminum compound such as aluminum chloride or trialkoxy aluminum may be used as needed. In addition, "(meth)acryloyloxy" in this specification means both acryloyloxy and methacryloyloxy. The same applies to other similar terms.

In the case of n = 0 in the above general formula (A), the alkoxysilane compound becomes tetraalkoxysilane, and the tetraalkoxysilane is completely hydrolyzed and polycondensed to obtain an inorganic silica-based compound, which is partially hydrolyzed and polycondensed. By doing so, a polyorganosiloxane-based compound or a mixture of an inorganic silica-based compound and a polyorganosiloxane-based compound is obtained.

In the case of n = 1 to 3 in the above general formula (A), the alkoxysilane compound has a non-hydrolyzable group, and a polyorganosiloxane-based compound is obtained by partially or completely hydrolyzing and polycondensing the compound.

Examples of the alkoxysilane compound represented by the general formula (A) include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxy Silane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyl Triethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-acryloyloxypropyltrimethoxy Silane, γ-methacryloyloxypropyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, divinyldimethoxysilane, divinyldiethoxysilane, tri Vinyl methoxysilane, trivinyl ethoxysilane, etc. are mentioned. These may be used independently and may be used in combination of 2 or more type.

In addition to being obtained by the above method, the siloxane compound may be obtained by hydrolyzing a silicon compound such as sodium metasilicate, sodium orthosilicate or water glass (sodium silicate mixture). This hydrolysis can be accelerated by the action of an acid such as hydrochloric acid, sulfuric acid or nitric acid, or a metal compound such as magnesium chloride or calcium sulfate. Free silicic acid is produced by this hydrolysis, and a chain, cyclic or mesh siloxane compound is obtained by polymerization of the silicic acid. Depending on the kind of silicon compound used as a raw material, it may be decided which state of a chain shape, a ring shape, and a network shape. For example, the siloxane compound obtained from water glass has the following general formula (B)

[Formula 1]

(m represents the degree of polymerization, R is a hydrogen atom, a silicon atom, or a metal atom such as magnesium or aluminum.) The chain structure represented by is the main component.

Other examples of the siloxane compound include silica gel (SiO _X ·nH ₂ O) which is an inorganic silica-based compound.

The low refractive index layer 4 of the present embodiment may be formed of a cured product obtained by curing a composition containing an active energy ray-curable compound with active energy rays. Here, the active energy ray-curable compound means a polymerizable compound that has energy quanta in electromagnetic waves or charged particle beams, that is, is crosslinked and cured by irradiation with ultraviolet rays or electron beams. Examples of such active energy ray-curable compounds include photopolymerizable prepolymers and/or photopolymerizable monomers.

The photopolymerizable prepolymer includes a radical polymerization type and a cationic polymerization type, and examples of the radical polymerization type photopolymerizable prepolymer include polyester acrylate-based, epoxy acrylate-based, urethane acrylate-based, and polyols. An acrylate type|system|group etc. are mentioned. Here, as the polyester acrylate-based prepolymer, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends obtained by condensation of a polyhydric carboxylic acid and a polyhydric alcohol with (meth)acrylic acid, or , It can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding an alkylene oxide to a polyhydric carboxylic acid with (meth)acrylic acid.

The epoxy acrylate-based prepolymer can be obtained, for example, by reacting (meth)acrylic acid with the oxylan ring of a relatively low molecular weight bisphenol-type epoxy resin or novolak-type epoxy resin to esterify it. Examples of the epoxy acrylate-based prepolymer include phenol novolak-based prepolymers. The urethane acrylate-based prepolymer can be obtained by, for example, esterifying a polyurethane oligomer obtained by reaction of polyether polyol or polyester polyol with polyisocyanate with (meth)acrylic acid. And the polyol acrylate-type prepolymer can be obtained by esterifying the hydroxyl group of polyether polyol with (meth)acrylic acid. These photopolymerizable prepolymers may be used singly or in combination of two or more.

On the other hand, as the photopolymerizable prepolymer of the cationic polymerization type, an epoxy resin is usually used. Examples of the epoxy-based resin include compounds obtained by epoxidizing polyhydric phenols such as bisphenol resins and novolac resins with epichlorohydrin or the like, compounds obtained by oxidizing linear olefin compounds or cyclic olefin compounds with peroxides, etc. etc. can be mentioned.

In addition, as a photopolymerizable monomer, for example, 1,4-butanedioldi(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, neopentylglycoldi(meth)acrylate, polyethylene glycoldi (meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyldi(meth)acrylate, caprolactone modified dicyclopentenyldi( Meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipenta Erythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl) ) Polyfunctional acrylates such as isocyanurate, propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate can be heard Among these, it is preferable to use dipentaerythritol hexaacrylate from the viewpoint of easy obtaining desired physical properties of the low refractive index layer 4. These photopolymerizable monomers may be used alone or in combination of two or more, or may be used together with the photopolymerizable prepolymer.

These polymerizable compounds can use a photopolymerization initiator together if desired. As this photopolymerization initiator, for radical polymerization type photopolymerizable prepolymers and photopolymerizable monomers, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n -Butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2 -Methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4 -(2-hydroxyethoxy)phenyl-2(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthra Quinone, 2-ethylanthraquinone, 2-tertiary-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthio Oxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylamine benzoic acid ester, etc. are mentioned. Among these, it is preferable to use 1-hydroxycyclohexyl phenyl ketone. In addition, as a photopolymerization initiator for the photopolymerizable prepolymer of the cationic polymerization type, for example, onium such as aromatic sulfonium ion, aromatic oxosulfonium ion, aromatic iodonium ion, tetrafluoroborate, hexafluoro and compounds composed of anions such as phosphate, hexafluoroantimonate, and hexafluoroarsenate. These may be used singly or in combination of two or more. Moreover, the compounding amount is suitably selected from the range of 0.2-10 mass parts normally with respect to 100 mass parts of said photopolymerizable prepolymers and/or photopolymerizable monomers.

The low refractive index layer 4 of the present embodiment may also contain refractive index adjusting particles from the viewpoint of achieving a desired refractive index. In particular, when the low refractive index layer 4 of the present embodiment is constituted by using a composition containing an active energy ray-curable compound as a material, it is preferable to add refractive index adjusting particles to the composition. Examples of the particles for adjusting the refractive index include silica sol, porous silica fine particles and hollow silica fine particles.

As the silica sol, colloidal silica obtained by suspending silica fine particles having an average particle diameter of about 0.005 to 1 μm, preferably 10 nm to 100 nm in a colloidal state in an alcohol-based or cellosolve-based organic solvent can be preferably used. In addition, the average particle diameter can be determined by a dynamic light scattering method.

In addition, since the hollow silica fine particles and porous silica fine particles have minute voids in the fine particles in an open or closed state, and are filled with gas, for example, air having a refractive index of 1, the fine particles themselves have a low refractive index. It has a characteristic. When the fine particles are uniformly dispersed in the coating film without forming aggregates, the effect of lowering the refractive index of the coating film is high, and at the same time, the transparency is excellent. Compared with normal colloidal silica particles without pores (refractive index n = about 1.46), the refractive index of hollow silica fine particles and porous silica fine particles having pores is as low as 1.20 to 1.45.

The hollow silica fine particles and porous silica fine particles are fine particles having an average particle diameter of about 5 nm to 300 nm, preferably 5 nm to 200 nm, and particularly preferably 10 nm to 100 nm, and the average pore size of the pores is 10 nm to 100 nm. It is about 100 nm and is a hollow silica fine particle or porous silica fine particle having closed cells and/or open cells containing air. The refractive index of the whole fine particles is about 1.20 to 1.45. Even if the refractive index of the cured product of the active energy ray-curable compound is 1.45 or more, the refractive index as a whole is increased by adding the hollow silica fine particles or porous silica fine particles used in the present embodiment to the active energy ray-curable compound to form the low refractive index layer 4. can lower Further, since the hollow silica fine particles and porous silica fine particles are dispersed in the low refractive index layer 4, the low refractive index layer 4 has excellent transparency. In addition, the average particle diameter can be determined by a dynamic light scattering method.

Moreover, the organic compound containing a polymerizable unsaturated group may couple|bond with the particle|grains for refractive index adjustment. For example, an organic compound containing a polymerizable unsaturated group may be bonded to the fine silica particles. The silica fine particles to which the polymerizable unsaturated group-containing organic compound is bound reacts a polymerizable unsaturated group-containing organic compound having a functional group capable of reacting with the silanol group with a silanol group on the surface of the silica fine particles having an average particle diameter of about 0.005 to 1 μm. can be obtained by doing As a polymerizable unsaturated group, a radically polymerizable acryloyl group, methacryloyl group, etc. are mentioned, for example.

In the low refractive index layer 4 of the present embodiment, the blending ratio of the refractive index adjusting particles to the matrix resin composition is appropriately set so that the refractive index and surface area increase rate of the low refractive index layer 4 formed fall within the above ranges. For example, with respect to 100 parts by mass of the matrix resin composition, the refractive index adjusting particles are preferably less than 100 parts by mass, particularly preferably 60 parts by mass or less, and more preferably 30 parts by mass or less. However, as described above, the low refractive index layer 4 preferably does not contain refractive index adjusting particles from the viewpoint of achieving excellent surface smoothness.

The low refractive index layer 4 in the present embodiment can contain desired various additives within a range that does not hinder the effects of the present invention. As various additives, a dispersing agent, a dye, a pigment, a crosslinking agent, a curing agent, an antioxidant, etc. are mentioned, for example.

As a material constituting the low refractive index layer 4 of the present embodiment, the above-described siloxane compound and active energy ray-curable compound may be used in combination. And you may add the particle|grains for refractive index adjustment mentioned above with respect to them. However, from the viewpoint of easy expression of desired physical properties, the low refractive index layer 4 is preferably composed of only a siloxane compound or a combination of an active energy ray-curable compound and refractive index adjusting particles.

<High refractive index layer>

In the transparent conductive film lamination film (1) according to the present embodiment, a high refractive index layer (3) having a refractive index greater than the refractive index of the low refractive index layer (4) is provided between the transparent plastic substrate (2) and the low refractive index layer (4). ) may intervene. In this case, the high refractive index layer 3 is preferably directly laminated on the transparent plastic substrate 2 or laminated with an easily adhesive layer interposed therebetween. By forming the high refractive index layer 3, the pattern of the transparent conductive film can be made invisible by the low refractive index layer 4 and the high refractive index layer 3.

The high refractive index layer 3 of the transparent conductive film lamination film 1 according to the present embodiment preferably has a refractive index of 1.60 to 1.90, particularly preferably 1.65 to 1.85, and further preferably 1.68 to 1.80. do. When the refractive index of the high refractive index layer 3 is 1.60 to 1.90, a sufficient refractive index difference with the low refractive index layer 4 can be secured, and the pattern of the transparent conductive film can be effectively made invisible, and in this embodiment Other physical properties such as transparency of the related transparent conductive film lamination film 1 become good.

Examples of the material constituting the high refractive index layer 3 in the present embodiment include thermoplastic resins and active energy ray-curable compounds.

When the high refractive index layer 3 in the present embodiment is constituted using a thermoplastic resin, the high refractive index layer 3 containing the thermoplastic resin has good adhesion to the transparent plastic substrate 2 and low refractive index layer 4 ), it has excellent adhesion, and it fulfills the same role as the easily adhesive layer itself.

Specifically, since the thermoplastic resin contained in the high refractive index layer 3 has a polarity (or composition) close to the surface of the transparent plastic substrate 2, and exhibits high affinity to the transparent plastic substrate 2, The high refractive index layer 3 can be adhered to the transparent plastic substrate 2. On the other hand, when a material of the low refractive index layer 4 containing an organic solvent is applied onto the high refractive index layer 3, the organic solvent in the material of the low refractive index layer 4 dissolves the thermoplastic resin in the high refractive index layer 3. Then, the low refractive index layer 4 can be adhered (welded) to the high refractive index layer 3 by the melted thermoplastic resin. This eliminates the need to separately form an easily bonding layer, and the layer configuration of the film 1 for lamination of transparent conductive films can be simplified.

Specific examples of the thermoplastic resin include polyester resins, polyurethane resins, acrylic resins, polyolefin resins, polyvinyl chloride, polystyrene, polyvinyl alcohol, and polyvinylidene chloride. Among these, it is preferably at least one selected from polyester resins, polyurethane resins, and acrylic resins, from the viewpoint of adhesion to the transparent plastic substrate (2) and weldability to the low refractive index layer (4), and polyester resins and polyurethanes. It is more preferable that it is at least 1 sort(s) chosen from resin, and it is still more preferable that it is a polyester resin.

When the high refractive index layer 3 in the present embodiment is constituted using an active energy ray-curable compound, the same active energy ray-curable compound for forming the low refractive index layer 4 can be used. The high refractive index layer 3 can be formed by curing the composition containing the active energy ray-curable compound with an active energy ray. Here, the high refractive index layer 3 needs to have a higher refractive index than the low refractive index layer 4 . From this point of view, as the active energy ray-curable compound used for constituting the low refractive index layer 4, it is preferable to select a compound having no aromatic ring or heterocyclic ring in the molecule. On the other hand, the high refractive index layer 3 It is preferable to select what has an aromatic ring and/or a heterocyclic ring in a molecule|numerator as an active energy ray-curable compound used for a structure. Moreover, the refractive index of the high refractive index layer 3 can be made high, for example by containing the metal oxide mentioned later in the high refractive index layer 3. As a material constituting the high refractive index layer 3, it is preferable to use a phenol novolac-based prepolymer among the above-mentioned active energy ray-curable compounds from the viewpoint of obtaining desired physical properties of the high refractive index layer 3 easily. Alternatively, the high refractive index layer 3 may be constituted by combining an active energy ray-curable compound and the thermoplastic resin described above.

The high refractive index layer 3 in the present embodiment preferably contains a material for adjusting the refractive index (hereinafter sometimes referred to as a "refractive index adjuster"), for example, a metal oxide. Metal oxides that can be contained in the high refractive index layer 3 are not particularly limited, and examples include titanium oxide, zirconium oxide, tantalum oxide, zinc oxide, indium oxide, hafnium oxide, cerium oxide, tin oxide, niobium oxide, Tin doped indium oxide (ITO), antimony doped tin oxide (ATO), etc. are mentioned. These metal oxides may be used individually by 1 type, and may be used in combination of 2 or more type. Especially, it is preferable to use titanium oxide and/or zirconium oxide from a viewpoint of a refractive index.

The above metal oxide is preferably contained in the high refractive index layer 3 in the form of fine particles. In this case, the average particle diameter of the metal oxide fine particles is preferably 0.005 to 1 μm, more preferably 0.01 to 0.1 μm. In addition, the average particle diameter of metal oxide fine particles in this specification is taken as the value measured by the measuring method using the zeta potential measuring method.

The blending ratio of the metal oxide in the high refractive index layer 3 is appropriately set so that the refractive index of the high refractive index layer 3 falls within the above-mentioned range. Specifically, it is preferably about 50 to 1000 parts by mass, particularly preferably 80 to 800 parts by mass, and still more preferably 100 to 500 parts by mass, based on 100 parts by mass of the active energy ray-curable compound and/or thermoplastic resin.

The high refractive index layer 3 in the present embodiment can contain desired various additives within a range not interfering with the effect of the present invention. As various additives, a dispersing agent, a dye, a pigment, a crosslinking agent, a curing agent, an antioxidant, etc. are mentioned, for example.

The thickness of the high refractive index layer 3 is 20 to 150 nm, preferably 30 to 130 nm, and more preferably 50 to 110 nm. When the thickness of the high refractive index layer 3 is within this range, it is possible to make it difficult to visually recognize the pattern of the transparent conductive film, and the adhesion between the high refractive index layer 3 and the transparent plastic substrate 2 and the low refractive index layer 4 is improved. This becomes excellent, and by extension, the smoothness of the surface of the high refractive index layer 3 becomes sufficient. In addition, the thickness of the high refractive index layer 3 in this specification is a value measured by an ellipsometer, and specific measurement conditions are as showing in the Example mentioned later.

<Transparent plastic substrate>

The transparent plastic substrate 2 used in this embodiment is not particularly limited, and a transparent plastic film can be appropriately selected and used from known plastic films as conventional optical substrates. Examples of such plastic films include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate (PEN), polyethylene films, polypropylene films, cellophane, diacetyl cellulose films, and triacetyl cellulose films. Acetylcellulose film, acetylcellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, Plastic films such as polyetheretherketone film, polyethersulfone film, polyetherimide film, polyimide film, fluororesin film, polyamide film, acrylic resin film, norbornene resin film, cycloolefin resin film, or laminates thereof film can be taken.

Among the above, a polyester film, a polycarbonate film, a polyimide film, a norbornene-based resin film, a cycloolefin resin film, and the like are preferable from the viewpoint of having strength suitable for a touch panel or the like. Among these, from viewpoints of transparency, thickness precision, etc., a polyester film is particularly preferred, and polyethylene terephthalate (PET) is more preferred.

When polyethylene terephthalate (PET) is used as the transparent plastic substrate 2, since PET is excellent in adhesion, it is not necessary to form an easily bonding layer that improves adhesion with the high refractive index layer. In addition, when an easily bonding layer is not provided, PET has a refractive index as high as 1.65, and since PET can function as a substitute for a high refractive index layer, the high refractive index layer 3 does not necessarily need to be provided.

The thickness of the transparent plastic substrate 2 is not particularly limited and is appropriately selected depending on the application, but is usually in the range of 15 to 300 μm, preferably 30 to 250 μm. In addition, for the purpose of improving adhesion to a layer formed on the surface of this transparent plastic substrate 2, if desired, surface treatment can be performed on one or both surfaces by an oxidation method or a roughening method. As the oxidation method, for example, corona discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone/ultraviolet irradiation treatment, etc. are used, and as the roughening method, for example, sand blast method, solvent treatment method, etc. are used. do. These surface treatment methods are appropriately selected depending on the type of the transparent plastic substrate 2, but in general, a corona discharge treatment method is preferably used from the viewpoints of effectiveness and operability.

<Manufacture of Film for Lamination of Transparent Conductive Films>

The film 1 for lamination|stacking of transparent conductive films mentioned above can be manufactured, for example by the method shown below. Here, a production example of the film 1 for lamination of transparent conductive films in which the high refractive index layer 3 is formed between the low refractive index layer 4 and the transparent plastic substrate 2 will be described. In addition, in the film for laminating a transparent conductive film in which the low refractive index layer 4 is directly laminated on the transparent plastic substrate 2, the step of preparing and forming the high refractive index layer 3 is omitted in the production examples described below. And it can be manufactured by carrying out other processes similarly.

First, a coating agent for the high refractive index layer 3 containing a material constituting the high refractive index layer 3 and an organic solvent is prepared, and a low refractive index layer 4 containing a material constituting the layer 4 and an organic solvent is prepared. A coating agent for the refractive index layer 4 is prepared.

When an active energy ray-curable compound is used as a material constituting the high refractive index layer 3, the organic solvent used when preparing the coating agent for the high refractive index layer 3 has excellent solubility of the active energy ray-curable compound While, it is also preferable that the dispersibility of the above-mentioned refractive index adjuster is excellent. Cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate etc. are mentioned preferably as a specific example of such an organic solvent.

On the other hand, when an active energy ray-curable compound is used as a material constituting the low-refractive-index layer 4, the organic solvent used when preparing the coating agent for the low-refractive-index layer 4 depends on the solubility of the active energy ray-curable compound. In addition to being excellent, those having excellent dispersibility of the particles for adjusting the refractive index are also preferred. Specific examples of such an organic solvent are the same as the specific examples of the organic solvent described above in the case of using an active energy ray-curable compound as a material constituting the high refractive index layer 3.

Further, when the low refractive index layer 4 is composed of a siloxane compound, the organic solvent used when preparing the coating agent for the low refractive index layer 4 is preferably an alcohol solvent from the viewpoint of dissolution and dispersibility. . As an alcohol solvent, isopropyl alcohol, isobutyl alcohol, etc. are mentioned preferably, for example.

After preparing the coating agent for the high refractive index layer 3 and the low refractive index layer 4, first, the coating agent for the high refractive index layer 3 is applied to one side of the transparent plastic substrate 2. After that, the high refractive index layer 3 is formed by drying the coating agent and curing the coating film by irradiating active energy rays.

Then, the coating agent for the low refractive index layer (4) is applied on the high refractive index layer (3). When using a siloxane compound as a material constituting the low refractive index layer 4, the low refractive index layer 4 is formed by drying the coating agent. On the other hand, when an active energy ray-curable compound is used as a material constituting the low refractive index layer 4, the low refractive index layer 4 is formed by drying the coating agent and then curing the coating film by irradiating the active energy ray. By the above, the film 1 for lamination|stacking of a transparent conductive film is obtained.

Examples of the application method of the coating agent include a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, and a gravure coating method.

When forming the low-refractive-index layer 4 on the high-refractive-index layer 3, it is preferable to heat-process (dry-process) the coating agent for the low-refractive-index layer 4 at 30-70 degreeC for about 10 seconds - 3 minutes. When a siloxane compound is used as a material constituting the low-refractive-index layer 4, after the drying treatment, it is further heated at 110 to 150°C for about 5 seconds to 3 minutes to cure the coating agent. In the case where an active energy ray-curable compound is used as a material constituting the low refractive index layer 4, the coating agent is cured by irradiation with active energy rays after the drying treatment. As described above, by performing heat treatment (drying treatment) at 30 to 70°C for about 10 seconds to 3 minutes, the solvent can be partially or completely evaporated before curing of the material of the low refractive index layer (4) is completed, The occurrence of roughness on the surface of the low refractive index layer 4 caused by evaporation of the solvent can be suppressed.

As the active energy ray, ultraviolet rays, electron beams, and the like are usually used, and ultraviolet rays are particularly preferable. The irradiation amount of the active energy ray varies depending on the type of energy ray, but, for example, in the case of ultraviolet rays, the amount of light is preferably 50 to 1000 mJ/cm 2 , particularly preferably 100 to 500 mJ/cm 2 . In addition, in the case of an electron beam, about 0.1 to 50 kGy is preferable. Ultraviolet irradiation can be performed by a high-pressure mercury lamp, a fusion H lamp, a xenon lamp or the like. In addition, electron beam irradiation can be performed by an electron beam accelerator or the like.

The transparent conductive film lamination film 1 obtained as described above is preferably used as a manufacturing material for a transparent conductive film described below.

[Transparent Conductive Film]

2 is a cross-sectional view of a transparent conductive film according to an embodiment of the present invention. The transparent conductive film 10 according to the present embodiment is on the surface side opposite to the high refractive index layer 3 in the low refractive index layer 4 of the above-described transparent conductive film lamination film 1 (low refractive index layer 3 in FIG. 2). On the upper side of the refractive index layer 4), a transparent conductive film 5 is further laminated. In this transparent conductive film 10, the pattern of the transparent conductive film 5 is difficult to visually recognize due to the existence of the high refractive index layer 3 and the low refractive index layer 4.

<Transparent Conductive Film>

As the material of the transparent conductive film 5 in the transparent conductive film 10 according to the present embodiment, any material having both transparency and conductivity can be used without particular limitation. For example, tin-doped indium oxide (ITO ), iridium oxide (IrO ₂ ), indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), fluorine dope tin oxide (FTO), indium oxide-zinc oxide (IZO), zinc oxide (ZnO), gallium dope and transparent conductive metal oxides such as zinc oxide (GZO), aluminum-doped zinc oxide (AZO), molybdenum oxide (MoO ₃ ), and titanium oxide (TiO ₂ ). A thin film of these metal oxides becomes a transparent conductive film having both transparency and conductivity by adopting appropriate film formation conditions.

The thickness of the transparent conductive film 5 is preferably 4 to 800 nm, more preferably 5 to 500 nm, and particularly preferably 10 to 100 nm. When the thickness of the transparent conductive film 5 is in such a range, while it becomes a continuous thin film and stable conductivity is obtained, there is no fear that transparency will decrease.

Moreover, it is preferable that the refractive index of the transparent conductive film 5 is about 1.90-2.05.

<Physical properties>

In the transparent conductive film 10, when the transparent conductive film 5 is etched, the absolute value of the difference in reflectance (%) at a wavelength of 400 nm before and after etching is preferably 9 or less, and particularly preferably 8 or less and more preferably 6 or less. Here, the difference in reflectance before and after etching is the reflectance (unit: %) measured in the vicinity of wavelength 400 nm in accordance with JIS K7142 before and after etching the transparent conductive film 5, respectively. It is the value of the difference before and after etching in the said wavelength.

When the transparent conductive film 5 is etched, the absolute value of the reflectance difference at a wavelength of 400 nm before and after etching is 9 or less, so that the transparent conductive film 10 according to the present embodiment has excellent transparency, Under reflected light, the pattern of the transparent conductive film 5 becomes difficult to be visually recognized.

<Manufacture of transparent conductive film>

The transparent conductive film 10 according to this embodiment can be manufactured, for example, by the method shown below. First, after manufacturing the transparent conductive film lamination film 1 as described above, the surface side of the transparent conductive film lamination film 1 on which the low refractive index layer 4 is formed is subjected to vacuum evaporation or sputtering. , The transparent conductive film 10 is formed by laminating the transparent conductive film 5 by appropriately selecting a known method such as a CVD method, an ion plating method, a spray method, or a sol-gel method according to the type of the material or the required film thickness. can be manufactured

In addition, after forming the transparent conductive film 5 as described above, a resist mask having a predetermined pattern is formed by photolithography, and an etching process is performed by a known method to form, for example, a line-shaped pattern. etc. can be formed.

The transparent conductive film 10 according to the present embodiment is manufactured using the transparent conductive film lamination film 1 according to the present embodiment, so that the portion where the transparent conductive film is laminated can be made difficult to visually see, and the transparent conductive film The resistance value can be set to a desired value, and the workability at the time of forming wiring or the like on the surface of the low refractive index layer is excellent.

The embodiments described above are described for facilitating understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

Example

Hereinafter, the present invention will be described more specifically by examples and the like, but the scope of the present invention is not limited to these examples and the like.

In addition, the thicknesses of the high refractive index layer and the low refractive index layer in Examples or Comparative Examples shown below were determined by using a spectroscopic ellipsometer (manufactured by J. A. Woollam, product name: M-2000) at the stage of forming those layers. measured.

[Preparation Example 1] (coating agent for high refractive index layer H-1)

100 parts by mass (solid content conversion; hereinafter the same) of a phenol novolak-based ultraviolet curable prepolymer (Hitaloid 7663, solid content 80%, diluted in methyl isobutyl ketone (MIBK), manufactured by Hitachi Chemical Co., Ltd.) as an active energy ray-curable compound, and refractive index 300 parts by mass of zirconium oxide having an average particle diameter of 10 nm as a regulator and 5 parts by mass of 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, trade name: Irgacure 184) as a photopolymerization initiator were diluted with MIBK as a diluting solvent, Coating agent H-1 for a high refractive index layer was prepared.

[Preparation Example 2] (coating agent for high refractive index layer H-2)

Coating agent H-2 for a high refractive index layer was prepared in the same manner as in Preparation Example 1, except that titanium oxide having an average particle diameter of 10 nm was used as the refractive index adjuster.

[Preparation Example 3] (coating agent for low refractive index layer L-1)

100 parts by mass of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Industries, Ltd., trade name: NK ester A-DPH, solid content concentration: 100 mass%) as an active energy ray-curable compound, and hollow silica having an average particle diameter of 60 nm as particles for refractive index adjustment 25 parts by mass and 5 parts by mass of 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, trade name: Irgacure 184) as a photopolymerization initiator were diluted with MIBK as a diluting solvent to prepare a low refractive index layer coating agent L-1 did

[Preparation Example 4] (coating agent for low refractive index layer L-2)

100 parts by mass of a siloxane resin (product name: Colcoat P) as a siloxane compound was diluted with isopropyl alcohol (IPA) as a diluting solvent to prepare a coating agent L-2 for a low refractive index layer.

[Preparation Example 5] (coating agent for low refractive index layer L-3)

A coating agent for a low refractive index layer L-3 was prepared in the same manner as in Preparation Example 3, except that the blending amount of the particles for adjusting the refractive index was changed to 50 parts by mass.

[Preparation Example 6] (coating agent for low refractive index layer L-4)

Coating agent L-4 for a low refractive index layer was prepared in the same manner as in Preparation Example 3 except that the blending amount of the particles for adjusting the refractive index was changed to 12.5 parts by mass.

[Preparation Example 7] (coating agent for low refractive index layer L-5)

Preparation Example 3 except that the blending amount of the particles for adjusting the refractive index was changed to 12.5 parts by mass, and 8.2 parts by mass of a reactive fluorine oligomer (manufactured by DIC, trade name: Megafac RS-75, solid content: 40%, diluted with MIBK) was further added as an antifouling agent. Coating agent L-5 for a low refractive index layer was prepared in the same manner as above.

[Preparation Example 8] (coating agent for low refractive index layer L-6)

Coating agent L-6 for a low refractive index layer was prepared in the same manner as in Preparation Example 3 except that the particles for adjusting the refractive index were not added.

[Preparation Example 9] (coating agent for low refractive index layer L-7)

Coating agent L-7 for a low refractive index layer was prepared in the same manner as in Preparation Example 3 except that the blending amount of the particles for adjusting the refractive index was changed to 100 parts by mass.

[Preparation Example 10] (coating agent for low refractive index layer L-8)

A coating agent for a low refractive index layer L-8 was prepared in the same manner as in Preparation Example 7 except that the amount of the antifouling agent was changed to 11.8 parts by mass.

Here, the formulation of Preparation Examples 1 to 10 is shown in Table 1. In addition, the details of the abbreviation etc. described in Table 1 are as follows.

[diluted solvent]

MIBK: methyl isobutyl ketone

IPA: isopropyl alcohol

[Example 1]

As a transparent plastic substrate, a polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., trade name: Cosmo Shine A4100, thickness: 50 μm) having an easily adhesive layer on one side, on the surface opposite to the easily adhesive layer, the low obtained in Preparation Example 3 Coating agent L-1 for the refractive index layer was coated with a Meyer bar. After drying this in a 50 degreeC oven for 1 minute, a 35 nm-thick low refractive index layer was formed by irradiating 200 mJ/cm<2> ultraviolet-ray with a high pressure mercury lamp in nitrogen atmosphere, and the film for lamination|stacking of a transparent conductive film was obtained. On the low refractive index layer of the obtained transparent conductive film lamination film, sputtering was performed using an ITO target (tin oxide 10% by mass) to form a transparent conductive film having a thickness of 30 nm to prepare a transparent conductive film. In addition, according to measurement using a spectroscopic ellipsometer described later, the refractive index of the transparent conductive film was 1.95. In addition, the transparent conductive film was formed so that a portion where the transparent conductive film was not laminated remained in consideration of the visibility test described later.

[Example 2]

A transparent conductive film was produced in the same manner as in Example 1 except that the thickness of the low refractive index layer was 50 nm.

[Example 3]

As a transparent plastic substrate, a polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., trade name: Cosmo Shine A4100, thickness: 50 μm) having an easily adhesive layer on one side, on the surface opposite to the easily adhesive layer, the low obtained in Preparation Example 4 Coating agent L-2 for the refractive index layer was coated with a Meyer bar. After drying this in a 50 degreeC oven for 20 second, it was made to harden by heating at 130 degreeC for 40 second, and the low refractive index layer of thickness 35 nm was formed, and the film for transparent conductive film lamination|stacking was obtained. On the low refractive index layer of the obtained transparent conductive film lamination film, sputtering was performed using an ITO target (tin oxide 10% by mass) to form a transparent conductive film having a thickness of 30 nm to prepare a transparent conductive film. Moreover, according to the measurement using the spectroscopic ellipsometer mentioned later, the refractive index of the transparent conductive film was 1.95. In addition, the transparent conductive film was formed so that a portion where the transparent conductive film was not laminated remained in consideration of the visibility test described later.

[Example 4]

A transparent conductive film was produced in the same manner as in Example 1, except that the low refractive index layer coating agent L-3 obtained in Preparation Example 5 was used as the low refractive index layer coating agent.

[Example 5]

A transparent conductive film was produced in the same manner as in Example 1, except that the low refractive index layer coating agent L-4 obtained in Preparation Example 6 was used as the low refractive index layer coating agent.

[Example 6]

A transparent conductive film was produced in the same manner as in Example 1, except that the low refractive index layer coating agent L-5 obtained in Preparation Example 7 was used as the low refractive index layer coating agent.

[Example 7]

As a transparent plastic substrate, a polyethylene terephthalate (PET) film having a high refractive index adhesive layer on one side and a low coherence adhesive layer on the other side (manufactured by Mitsubishi Resins, trade name: Diafoil O901, thickness 125 μm) ), a transparent conductive film was produced in the same manner as in Example 1 except that the coating agent for the low refractive index layer was applied to the surface having the high refractive index easily bonding layer of the film.

[Example 8]

A polyethylene terephthalate (PET) film (trade name: Cosmo Shine A4100, thickness: 125 µm, manufactured by Toyobo Co., Ltd., manufactured by Toyobo Co., Ltd., 125 μm in thickness) having an easily adhesive layer on one side as a transparent plastic substrate, on the surface opposite to the easily adhesive layer, the high obtained in Preparation Example 1 Coating agent H-1 for the refractive index layer was coated with a Meyer bar. After drying this in a 50 degreeC oven for 1 minute, the high refractive index layer of thickness 50 nm was formed by irradiating 200 mJ/cm<2> ultraviolet-ray with a high-pressure mercury lamp in nitrogen atmosphere. Additionally, the low refractive index layer coating agent L-1 obtained in Preparation Example 3 was coated on the high refractive index layer with a Meyer bar. After drying this in a 50 degreeC oven for 1 minute, a 35 nm-thick low refractive index layer was formed by irradiating 200 mJ/cm<2> ultraviolet-ray with a high pressure mercury lamp in nitrogen atmosphere, and the film for lamination|stacking of a transparent conductive film was obtained. On the low refractive index layer of the obtained transparent conductive film lamination film, sputtering was performed using an ITO target (tin oxide 10% by mass) to form a transparent conductive film having a thickness of 30 nm to prepare a transparent conductive film. Moreover, according to the measurement using the spectroscopic ellipsometer mentioned later, the refractive index of the transparent conductive film was 1.95. In addition, the transparent conductive film was formed so that a portion where the transparent conductive film was not laminated remained in consideration of the visibility test described later.

[Example 9]

As a transparent plastic substrate, a polyethylene terephthalate (PET) film having a high refractive index adhesive layer on one side and a low coherence adhesive layer on the other side (manufactured by Mitsubishi Resins, trade name: Diafoil O901, thickness 125 μm) ) was used to coat the high refractive index layer coating agent on the surface having the high refractive index easily adhesive layer of the film, and further, as the high refractive index layer coating agent, Example except that the high refractive index layer coating agent H-2 obtained in Preparation Example 2 was used In the same manner as in 8, a transparent conductive film was produced.

[Comparative Example 1]

A transparent conductive film was produced in the same manner as in Example 1 except that the thickness of the low refractive index layer was changed to 80 nm.

[Comparative Example 2]

A transparent conductive film was produced in the same manner as in Example 1, except that the low refractive index layer coating agent L-6 obtained in Preparation Example 8 was used as the low refractive index layer coating agent.

[Comparative Example 3]

A transparent conductive film was produced in the same manner as in Example 1, except that the low refractive index layer coating agent L-7 obtained in Preparation Example 9 was used as the low refractive index layer coating agent.

[Comparative Example 4]

A transparent conductive film was produced in the same manner as in Example 1, except that the low refractive index layer coating agent L-8 obtained in Preparation Example 10 was used as the low refractive index layer coating agent.

[Test Example 1] (measurement of refractive index)

Each of the coating agent for the high refractive index layer and the coating agent for the low refractive index layer obtained in Preparation Examples 1 to 10 was a polyethylene terephthalate (PET) film (trade name: Cosmo Shine A4100, thickness 50 μm) having an easily adhesive layer on one side. It was coated on the surface opposite to the easily bonding layer, and a low refractive index layer and a high refractive index layer were formed under the same conditions as in Examples and Comparative Examples.

The refractive indices of the obtained low-refractive-index layer and high-refractive-index layer were measured using a spectroscopic ellipsometer (manufactured by J. A. Woollam, product name: M-2000) under conditions of a measurement wavelength of 589 nm and a measurement temperature of 23°C. At the time of measurement, the surface opposite to the surface on which the low-refractive-index layer or high-refractive-index layer was formed was rubbed with sandpaper, and it was painted in black with an oil pen (Zebra Co., Ltd., Matky Black), and the measurement was carried out. The refractive index at a wavelength of 589 nm was employed. A result is shown in Table 2.

In addition, a polyethylene terephthalate (PET) film (manufactured by Mitsubishi Resins, trade name: Diafoil O901, thickness 125 μm) having a high refractive index easily bonding layer on one side and a low coherence bonding layer on the other side. The refractive index of the adhesive layer was also measured under the above conditions using the above spectroscopic ellipsometer. A result is shown in Table 2.

[Test Example 2] (Measurement of surface area increase rate of low refractive index layer)

For each transparent conductive film obtained in Examples and Comparative Examples, an image of the surface of the low refractive index layer opposite to the transparent plastic base material was viewed using a laser microscope (manufactured by Keyence Corporation, product name: VK-9700) at a magnification of 900. obtained by ship.

In the obtained image, a square area of 4.992 μm square was arbitrarily selected, and the surface length of the low refractive index layer corresponding to one side of the square was measured on the surface, and this was taken as the vertical surface length. In addition, the surface length on the surface of the low refractive index layer corresponding to the other side orthogonal to the side was measured, and this was taken as the horizontal surface length.

Selection of these squares and measurement of the surface length were further performed twice. The average value was calculated from the obtained three vertical surface lengths, and the average value was calculated from the obtained three horizontal surface lengths. The product of these average values is the real surface area, and the following formula (I)

The surface area increase rate was calculated from A result is shown in Table 2.

[Test Example 3] (Measurement of Resistance Value of Transparent Conductive Film)

After sputtering using an ITO target (10% by mass of tin oxide) on the low refractive index layer of each transparent conductive film lamination film obtained in Examples and Comparative Examples, it was annealed at 150°C for 30 minutes to crystallize ITO.

This sample was placed on a glass plate, and using a resistivity meter (manufactured by Mitsubishi Chemical Analytec, product name: Loresta AX) equipped with a probe (4-probe ASP probe, product name: MCP-TP03P, manufactured by Mitsubishi Chemical Analytec, Inc.) , the resistance value of the transparent conductive film was measured. A result is shown in Table 2. In addition, when the resistance value is 400 Ω/□ or less, it is judged to be good.

[Test Example 4] (Evaluation of invisible performance)

Regarding each transparent conductive film obtained in Examples and Comparative Examples, the reflectance (unit: %) at a wavelength of 400 nm was measured with a spectrophotometer (manufactured by Shimadzu Corporation) for each of the portion where the transparent conductive film was formed and the portion where it was not formed. , product name: UV-3600). The difference in reflectance between the part where the transparent conductive film was formed and the part where it was not formed was calculated, and the absolute value was obtained. A result is shown in Table 2.

And based on the absolute value of the difference in reflectance, invisible performance was evaluated by the criteria shown below. An evaluation result is shown in Table 2.

○: The absolute value of the reflectance difference is 0 to 7

△: The absolute value of the reflectance difference is 7 to 9

×: The absolute value of the reflectance difference exceeds 9

In addition, invisible performance was also evaluated visually. Each transparent conductive film obtained in Examples and Comparative Examples was installed at a position of 1 m from a white fluorescent lamp (27 W; 3 wavelengths) so that the transparent conductive film was on the side of the white fluorescent lamp. With a white fluorescent light shining on the transparent conductive film, visually observing the vicinity of the end where the transparent conductive films are laminated on the transparent conductive film from a position 30 cm from the transparent conductive film on the side where the white fluorescent light is installed. did Then, whether or not there was a change in color tone at the boundary between the point where the transparent conductive film was laminated and the point where it was not laminated (the boundary between the presence and absence of the transparent conductive film) was evaluated according to the criteria shown below. A result is shown in Table 2.

○: No change in color tone is seen at the boundary between the presence and absence of a transparent conductive film.

(triangle|delta): The change of color tone is barely seen at the boundary of the presence or absence of a transparent conductive film.

x: A change in color tone is seen at the boundary between the presence and absence of a transparent conductive film.

[Test Example 5] (Measurement of surface free energy of low refractive index layer)

Regarding each transparent conductive film lamination film obtained in Examples and Comparative Examples, the contact angles of various liquid droplets with respect to the surface on which the low refractive index layer exists were measured, and based on the measured values, the Surface free energy (mJ/m 2 ) was obtained. The contact angle was measured according to JIS R3257 by a static method using a contact angle meter (DM-701 manufactured by Kyowa Interface Science Co., Ltd.). For the droplets, diiodomethane was used as the "dispersion component", 1-bromonaphthalene was used as the "dipole component", and distilled water was used as the "hydrogen bond component". A result is shown in Table 2.

[Test Example 6] (Evaluation of wiring workability of low refractive index layer)

Silver paste (product name: FA-401CA, manufactured by Fujikura Kasei Co., Ltd.) was screen-printed on the surface of each transparent conductive film obtained in Examples and Comparative Examples on which the transparent conductive film was present, and the width of the silver paste was 5 mm and the gap between the silver pastes was obtained. A 0.5 mm silver wiring was formed. The formed silver wiring was visually evaluated according to the criteria shown below. A result is shown in Table 2.

○: Wiring is neatly formed.

×: The wiring is not formed neatly due to paste agglomeration and end portions becoming jagged.

Table 2 shows the configurations of Examples 1 to 9 and Comparative Examples 1 to 4 and the measurement results of Test Examples 1 to 6. In addition, the details of the abbreviation and the like described in Table 2 are as follows.

[write]

Cosmo Shine A4100: Polyethylene terephthalate (PET) film having an easily adhesive layer on one side (manufactured by Toyobo Co., Ltd., trade name: Cosmo Shine A4100, thickness 50 μm)

Diafoil O901: Polyethylene terephthalate (PET) film having a high refractive index adhesive layer on one side and a low coherence adhesive layer on the other side (manufactured by Mitsubishi Resin, trade name: Diafoil O901, thickness 125 μm)

As is clear from Table 2, the transparent conductive films produced in Examples exhibited a lower surface area increase rate and higher surface free energy compared to Comparative Examples. In the transparent conductive films prepared in Examples, the resistance value of the transparent conductive film took a low value, showed excellent invisible performance, and exhibited excellent wiring workability.

In contrast, in Comparative Example 1 in which the thickness of the low refractive index layer was thick, the patterning invisible performance was insufficient. Further, in Comparative Example 2, where the refractive index of the low-refractive-index layer was high, the patterning invisible performance was insufficient. Further, in Comparative Example 3 in which the content of refractive index adjusting particles in the low refractive index layer was high, the rate of increase in the surface area of the low refractive index layer increased and the resistance value of the transparent conductive layer increased. Further, in Comparative Example 4 in which the low refractive index layer contained a fluorine-containing compound, the surface free energy was lowered and wiring workability was deteriorated.

The present invention is suitable for production of transparent conductive films for capacitive touch panels.

1 Film for lamination of transparent conductive films
2 Transparent plastic backing
3 high refractive index layer
4 low refractive index layer
10 transparent conductive film
5 transparent conductive film

Claims (7)

A transparent plastic substrate;
A film for laminating a transparent conductive film having a low refractive index layer formed on at least one side of the transparent plastic substrate,
The refractive index of the low refractive index layer is 1.30 to 1.50,
On the surface of the low refractive index layer opposite to the transparent plastic substrate, a 4.992 µm square area is arbitrarily selected, and the surface length of the surface of the low refractive index layer corresponding to one side of the square is When the product of the surface length of the surface of the low refractive index layer corresponding to the other side orthogonal to the side is the real surface area, the following formula (I)
[Equation 1]

The surface area increase rate calculated by is 5% or less,
The surface free energy of the low refractive index layer is 25.0 to 100 mJ/m 2 ,
A film for laminating a transparent conductive film, characterized in that the thickness of the low refractive index layer is 2 to 70 nm. According to claim 1,
The low refractive index layer does not contain refractive index adjusting particles or contains refractive index adjusting particles in an amount of less than 100 parts by mass based on 100 parts by mass of the matrix resin composition constituting the low refractive index layer. dragon film. According to claim 1,
A film for laminating a transparent conductive film, characterized in that a high refractive index layer having a higher refractive index than the refractive index of the low refractive index layer is interposed between the transparent plastic substrate and the low refractive index layer. According to claim 3,
The film for laminating a transparent conductive film, characterized in that the refractive index of the high refractive index layer is 1.60 to 1.90. A method for producing the film for laminating a transparent conductive film according to any one of claims 1 to 4,
When forming the low refractive index layer, after coating the material constituting the low refractive index layer, heat treatment at 30 to 70 ° C. for 10 seconds to 3 minutes Production of a film for laminating a transparent conductive film, characterized in that method. The transparent conductive film lamination film according to any one of claims 1 to 4;
A transparent conductive film characterized by comprising a transparent conductive film laminated on a surface side opposite to the transparent plastic substrate in the low refractive index layer. According to claim 6,
In the transparent conductive film, when the transparent conductive film is etched, the absolute value of the difference in reflectance (%) at a wavelength of 400 nm before and after the etching is 9 or less.

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