JP4692553B2 - Laminated film - Google Patents

Description

  The present invention relates to a laminated film. The present invention also relates to a decorative film or a decorative sheet using the laminated film, and further to a decorative molded product.

  Thermoplastic resin (plastic) films are applied to various uses by taking advantage of their respective characteristics. For example, acrylic films are used for exterior members of automobiles and automobiles by taking advantage of their excellent transparency and weather resistance. It is preferably used as a surface decorating film such as an interior member. Polypropylene film is preferably used as a product packaging film, taking advantage of its excellent tensile strength and rigidity, and polyester film is used for PET bottles, etc., taking advantage of its excellent heat resistance and thin film formability. It is preferably used as a shrink film for labels.

JP-A-9-12741 JP-A-10-279766 JP 2000-86853 A JP 2003-183471 A

  The thermoplastic resin film as described above may be touched by humans in its usage environment. However, particularly when the frequency or degree is high, liquid traces remain or cracks occur due to the action of lactic acid in the sweat. Sometimes. Then, the objective of this invention is providing the thermoplastic resin film excellent in lactic acid resistance. And it is providing the decorative film or sheet for decorating which is excellent in lactic acid resistance using this thermoplastic resin film, and also providing a decorative molded product.

  As a result of intensive studies, the inventor has found that the above object can be achieved by providing a surface layer made of a methyl methacrylate-styrene copolymer resin and a polycarbonate resin on a base material layer made of a thermoplastic resin. The invention has been completed. That is, the present invention provides a laminated film in which a surface layer made of a methyl methacrylate-styrene copolymer resin and a polycarbonate resin is laminated on at least one surface of a base material layer made of a thermoplastic resin.

  For example, if the surface layer is laminated on one surface of the base material layer, this laminated film can be used as a decorative film by printing on the opposite surface. Moreover, this decorative film can also be made into a decorative sheet by laminating a thermoplastic resin sheet on the printed surface. Then, by laminating a thermoplastic resin molded product on the surface on which the decorative film is printed or on the surface on which the thermoplastic resin sheet of the decorative sheet is laminated, the lactic acid resistance is excellent. A decorative molded product can be obtained.

  The laminated film of the present invention is excellent in lactic acid resistance. By using this, a decorative film or a decorative sheet excellent in lactic acid resistance, and a decorative molded product can be obtained.

  Hereinafter, the present invention will be described in detail. The laminated film of the present invention is obtained by laminating a surface layer made of a methyl methacrylate-styrene copolymer resin (MS resin) and a polycarbonate resin on at least one surface of a base material layer made of a thermoplastic resin.

  Examples of the thermoplastic resin constituting the base layer include methacrylic resin, polyester resin, polycyclic olefin resin, acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinylidene fluoride resin (PVDF resin), and the like. . Although the kind is suitably selected by the use of the laminated body obtained, for example, if it is a surface decoration use, a highly transparent thing, especially a methacryl resin are used preferably.

  The methacrylic resin is a polymer mainly composed of a methacrylic acid ester, and may be a homopolymer of a methacrylic acid ester, or a methacrylic acid ester of 50% by weight or more and other monomers of 50% by weight or less. A copolymer may also be used. Here, as the methacrylic acid ester, an alkyl ester of methacrylic acid is usually used.

  The preferred monomer composition of the methacrylic resin is 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate, and 0 to 49% by weight of other monomers based on all monomers. More preferably, the alkyl methacrylate is 50 to 99.9% by weight, the alkyl acrylate is 0.1 to 50% by weight, and other monomers are 0 to 49% by weight.

  Here, examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and the like. The alkyl group usually has 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms. It is. Of these, methyl methacrylate is preferably used.

  Examples of alkyl acrylates include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like. The alkyl group usually has 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms. is there.

  The monomer other than alkyl methacrylate and alkyl acrylate may be a monofunctional monomer, that is, a compound having one polymerizable carbon-carbon double bond in the molecule, or a polyfunctional monofunctional monomer. Although it may be a monomer, that is, a compound having at least two polymerizable carbon-carbon double bonds in the molecule, a monofunctional monomer is preferably used. Examples of this monofunctional monomer include aromatic alkenyl compounds such as styrene, α-methylstyrene and vinyltoluene, and alkenyl cyan compounds such as acrylonitrile and methacrylonitrile. Examples of polyfunctional monomers include polyunsaturated carboxylic acid esters of polyhydric alcohols such as ethylene glycol dimethacrylate, butanediol dimethacrylate, trimethylolpropane triacrylate, allyl acrylate, allyl methacrylate, and cinnamon. Alkenyl esters of unsaturated carboxylic acids such as allyl acids, polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, aromatic polyalkenyl compounds such as divinylbenzene, etc. Can be mentioned.

  In addition, as for said alkyl methacrylate, alkyl acrylate, and monomers other than these, respectively, you may use those 2 or more types as needed.

  The glass transition temperature of the methacrylic resin is preferably 40 ° C. or higher, and more preferably 60 ° C. or higher, from the viewpoint of heat resistance of the base material layer. This glass transition temperature can be appropriately set by adjusting the type of monomer and the ratio thereof.

  The methacrylic resin can be prepared by polymerizing the monomer component by a method such as suspension polymerization, emulsion polymerization or bulk polymerization. At that time, in order to obtain a suitable glass transition temperature or to obtain a viscosity showing a moldability to a suitable laminated film, it is preferable to use a chain transfer agent during the polymerization. The amount of the chain transfer agent may be appropriately determined according to the type of monomer and the ratio thereof.

  It is preferable from the viewpoint of the flexibility of the resulting laminated film that rubber particles are blended with a thermoplastic resin, particularly a methacrylic resin, and the base layer is constituted by the composition. Here, as the rubber particles, for example, acrylic, butadiene, styrene-butadiene, and the like can be used. Among these, acrylic rubber particles are preferably used from the viewpoint of weather resistance.

  The acrylic rubber particle is a particle containing an elastic polymer mainly composed of an acrylate ester as a rubber component, and may be a particle having a single layer structure made of only this elastic polymer, or a layer of this elastic polymer. However, from the viewpoint of the surface hardness of the base material layer, particles having a multilayer structure are preferable. The elastic polymer may be a homopolymer of an acrylate ester or a copolymer of 50% by weight or more of an acrylate ester and 50% by weight or less of other monomers. . Here, as the acrylic ester, an alkyl ester of acrylic acid is usually used.

  The preferable monomer composition of the elastic polymer mainly composed of acrylic acid ester is 50 to 99.9% by weight of alkyl acrylate based on all monomers, and 0 to 49% of other monofunctional monomers. 0.9% by weight and 0.1 to 10% by weight of the polyfunctional monomer.

  Here, the example of alkyl acrylate is the same as the example of alkyl acrylate mentioned above as a monomer component of methacrylic resin, The carbon number of the alkyl group is 1-8 normally, Preferably it is 4-8. is there.

  In addition, the monofunctional monomer other than the alkyl acrylate can be an alkyl methacrylate or other monofunctional monomer, and examples thereof include those of the alkyl methacrylate described above as the monomer component of the methacrylic resin. This is the same as the examples and examples of monofunctional monomers other than alkyl methacrylate and alkyl acrylate.

  Examples of the polyfunctional monomer are the same as the examples of the polyfunctional monomer previously mentioned as the monomer component of the methacrylic resin, and among them, alkenyl esters of unsaturated carboxylic acids and polybasic acids. Polyalkenyl esters are preferably used.

  In addition, as for said alkyl acrylate, the other monofunctional monomer, and a polyfunctional monomer, you may use those 2 or more types as needed, respectively.

  When the acrylic rubber particles having a multilayer structure are used, a preferable example is one having a polymer layer mainly composed of methacrylic acid ester outside the elastic polymer layer mainly composed of acrylate ester. That is, an at least two-layer structure in which an elastic polymer mainly composed of an acrylate ester is used as an inner layer and a polymer mainly composed of a methacrylic acid ester is used as an outer layer. Here, as the methacrylic acid ester which is a monomer component of the polymer in the outer layer, alkyl methacrylate is usually used. The outer layer polymer is usually formed at a ratio of 10 to 400 parts by weight, preferably 20 to 200 parts by weight with respect to 100 parts by weight of the inner layer elastic polymer. By setting the polymer of the outer layer to 10 parts by weight or more with respect to 100 parts by weight of the elastic polymer of the inner layer, the elastic polymer is hardly aggregated, and the transparency of the base material layer is improved.

  The preferable monomer composition of the polymer of the outer layer is 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate based on all monomers, and 0 to 50% by weight of other monomers. 49% by weight.

  Here, the example of alkyl methacrylate is the same as the example of alkyl methacrylate previously mentioned as a monomer component of a methacryl resin, The carbon number of the alkyl group is 1-8 normally, Preferably it is 1-4. is there. Of these, methyl methacrylate is preferably used.

  Moreover, the example of alkyl acrylate is the same as that of the alkyl acrylate mentioned above as a monomer component of a methacryl resin previously, The carbon number of the alkyl group is 1-8 normally, Preferably it is 1-4. .

  Monomers other than alkyl methacrylate and alkyl acrylate may be monofunctional monomers or polyfunctional monomers, but monofunctional monomers are preferably used. Examples of this monofunctional monomer are the same as the examples of monofunctional monomers other than the alkyl methacrylate and alkyl acrylate mentioned above as the monomer component of the methacrylic resin, Examples of the monomer are the same as those of the polyfunctional monomer mentioned above as the monomer component of the methacrylic resin.

  In addition, as for said alkyl methacrylate, alkyl acrylate, and monomers other than these, respectively, you may use those 2 or more types as needed.

  Further, as a preferred example of the acrylic rubber particles having a multilayer structure, a polymer layer mainly composed of a methacrylic acid ester is further provided inside the elastic polymer layer mainly composed of an acrylate ester which is the inner layer of the two-layer structure. In other words, the polymer mainly composed of methacrylic acid ester is used as the inner layer, the elastic polymer mainly composed of acrylate ester is used as the intermediate layer, and the polymer mainly composed of the methacrylic acid ester is used as the outer layer. There can also be mentioned at least a three-layer structure. Here, as a methacrylic acid ester which is a monomer component of the polymer of the inner layer, alkyl methacrylate is usually used. The polymer of the inner layer is usually formed at a ratio of 10 to 400 parts by weight, preferably 20 to 200 parts by weight, with respect to 100 parts by weight of the elastic polymer of the intermediate layer.

  The preferable monomer composition of the polymer of the inner layer is 70 to 100% by weight of alkyl methacrylate and 0 to 30% by weight of other monomers based on all monomers.

  Here, the example of alkyl methacrylate is the same as the example of alkyl methacrylate previously mentioned as a monomer component of a methacryl resin, The carbon number of the alkyl group is 1-8 normally, Preferably it is 1-4. is there. Of these, methyl methacrylate is preferably used.

  The monomer other than alkyl methacrylate may be an alkyl acrylate or other monofunctional monomer, or may be a polyfunctional monomer. And examples of this monofunctional monomer are the same as the examples of alkyl acrylates mentioned above as monomer components of methacrylic resins, and examples of monofunctional monomers other than alkyl methacrylates and alkyl acrylates. In addition, examples of the polyfunctional monomer are the same as the examples of the polyfunctional monomer previously mentioned as the monomer component of the methacrylic acid resin.

  In addition, as for said alkyl methacrylate and monomers other than these, respectively, you may use those 2 or more types as needed.

  Acrylic rubber particles can be prepared by polymerizing the monomer component of the above-mentioned elastic polymer mainly composed of an acrylate ester by at least one stage reaction by an emulsion polymerization method or the like. At this time, as described above, when a polymer layer mainly composed of methacrylic acid ester is formed outside the elastic polymer layer, the monomer component of the outer layer polymer is added to the elastic polymer layer. What is necessary is just to graft to the said elastic polymer by making it superpose | polymerize by reaction of at least 1 step | paragraph by emulsion polymerization method etc. in presence of a polymer. Further, as described above, when a polymer layer mainly composed of methacrylic acid ester is formed inside the elastic polymer layer, first, the monomer component of the polymer in the inner layer is Polymerization is carried out by at least one stage reaction by emulsion polymerization or the like, and then the monomer component of the elastic polymer is polymerized by at least one stage reaction by emulsion polymerization or the like in the presence of the resulting polymer. In the presence of the resulting elastic polymer, the monomer component of the outer layer polymer is polymerized in an at least one-stage reaction by an emulsion polymerization method or the like. To be grafted to the elastic polymer. When the polymerization of each layer is performed in two or more stages, it is sufficient that the monomer composition as a whole is within a predetermined range, not the monomer composition of each stage.

  Regarding the particle diameter of the acrylic rubber particles, the average particle diameter of the elastic polymer layer mainly composed of acrylic acid ester in the rubber particles is preferably 0.05 to 0.4 μm, and more preferably 0. The thickness is 1 to 0.3 μm, more preferably 0.14 to 0.25 μm. If the average particle size is too large, the transparency of the base material layer is lowered, which is not preferable. On the other hand, when the average particle size is too small, the surface hardness of the base material layer is lowered and easily scratched, or the flexibility of the base material layer is lowered and easily broken, which is not preferable. On the other hand, in order to suppress the whitening phenomenon that occurs when the film itself is bent, it is preferable that the particle diameter is small, and the structure is also the above two-layer structure (having no innermost hard layer). Is preferred.

  The average particle diameter was determined by mixing acrylic rubber particles with a methacrylic resin to form a film, dyeing the elastic polymer layer with ruthenium oxide in the cross section, and observing with an electron microscope. It can be determined from the diameter. That is, when acrylic rubber particles are mixed with methacrylic resin and the cross section thereof is dyed with ruthenium oxide, the methacrylic resin of the parent phase is not dyed, and the polymer mainly composed of methacrylic acid ester is outside the elastic polymer layer. If there is a layer, the polymer of this outer layer is not dyed, only the elastic polymer layer is dyed. The diameter can be determined. When a polymer layer mainly composed of methacrylic acid ester is present inside the elastic polymer layer, the polymer of the inner layer is not dyed and the outer elastic polymer layer is dyed 2 In this case, the outer diameter of the two-layer structure, that is, the outer diameter of the elastic polymer layer may be considered.

  The blending ratio of the methacrylic resin and the acrylic rubber particles is 20 to 95 parts by weight of the methacrylic resin and 5 to 80 parts by weight of the acrylic rubber particles based on the total of 100 parts by weight of both. If the ratio of the methacrylic resin is too small and the ratio of the acrylic rubber particles is too large, the surface hardness of the film is reduced and the film is easily damaged, and the appearance of the product after the shape transfer is deteriorated. On the other hand, if the proportion of the methacrylic resin is too large and the proportion of the acrylic rubber particles is too small, the flexibility of the film is lowered and the film is easily broken.

  The amount of the elastic polymer mainly composed of acrylic ester in the acrylic rubber particles is preferably 5 to 35 parts by weight based on the total of 100 parts by weight of the methacrylic resin and the acrylic rubber particles. More preferred are parts by weight. If the amount of the elastic copolymer is 5 parts by weight or more per 100 parts by weight of the total of the methacrylic resin and the acrylic rubber particles, the film forming property can be improved without the base material layer itself becoming brittle. . On the other hand, if the amount of the elastic copolymer is 35 parts by weight or less per 100 parts by weight of the total of methacrylic resin and acrylic rubber particles, the transparency and surface hardness of the base material layer can be improved.

  In addition to the rubber particles, the thermoplastic resin constituting the base material layer includes other components as necessary, for example, an ultraviolet absorber, an organic dye, an inorganic dye, a pigment, an antioxidant, and an antistatic agent. A surfactant or the like may be blended.

  The methyl methacrylate-styrene copolymer resin, which is one of the resins constituting the surface layer, is usually 1 to 30% by weight of methyl methacrylate units and 70 to 99% by weight of styrene units based on the total monomer units. Those having 2 to 15% by weight of methyl methacrylate units and 85 to 98% by weight of styrene units are preferably used. It is. If the proportion of methyl methacrylate units is too small, the breaking strength of the surface layer itself will be low, the whole film will be easily cracked, the surface hardness will be reduced, and further, the mixing properties with polycarbonate resin, especially the optical properties will be reduced. . Further, even if the proportion of methyl methacrylate units is too large, the mixing property with the polycarbonate resin, particularly the optical properties, is deteriorated. In addition, the methyl methacrylate-styrene copolymer resin may have a monomer unit other than the methyl methacrylate unit and the styrene unit, if necessary. Examples of the monomer unit include a divinylbenzene unit. And alkyl acrylate units, and the amount thereof is usually 10% by weight or less based on the total monomer units.

  The polycarbonate resin, which is the other resin constituting the surface layer, can generally be obtained by a condensation reaction between a divalent hydroxy compound and a carbonylating agent such as phosgene. In particular, bisphenol A was used as the divalent hydroxy compound. It is preferably an amorphous aromatic polycarbonate.

The molecular weight of the polycarbonate resin is preferably 30000 to 50000 in weight average, and more preferably 35000 to 45000. Further, the polycarbonate resin of the melt volume flow rate (MVR) is, 300 ° C., but is preferably 3 to 40 at 1.2kg load (cm ^3/10 min), is 5~15 (cm ^3/10 min) Is more preferable. MVR is measured according to ISO 1133.

  The surface layer is preferably composed of a mixed resin of the above-mentioned methyl methacrylate-styrene copolymer resin and polycarbonate resin, and both resins are melt-kneaded. The mixing ratio, expressed as a weight ratio of methyl methacrylate-styrene copolymer resin / polycarbonate resin, is usually 1/20 to 20/1, preferably 1/10 to 10/1, more preferably 1 / 5 to 5/1. When this weight ratio is too small, that is, when there is too little methyl methacrylate-styrene copolymer resin and too much polycarbonate resin, the heat resistance of the polycarbonate resin will cause the laminated film to be molded by thermoforming such as vacuum forming or pressure forming. , The molding cycle is extended and the production efficiency is lowered. On the other hand, if the weight ratio is too large, that is, if there is too much methyl methacrylate-styrene copolymer resin and too little polycarbonate resin, the fracture strength of the surface layer is lowered, and consequently the strength of the entire film is lowered. Adhesiveness with the methacrylic resin used suitably as a material layer worsens.

  The difference (Δη = η1-η2) between the refractive index (η1) of the methyl methacrylate-styrene copolymer resin and the refractive index (η2) of the polycarbonate resin is preferably −0.05 to 0.05. . If Δη is too small or too large, the haze of the mixed resin increases and the transparency of the film itself decreases. Δη can be easily adjusted by adjusting η1, and can be appropriately adjusted depending on the content ratio of methyl methacrylate units.

  The laminated film of the present invention is suitably obtained by coextrusion molding of a thermoplastic resin constituting the base material layer and a mixed resin comprising a methyl methacrylate-styrene copolymer resin and a polycarbonate resin constituting the surface layer. This co-extrusion method is appropriately selected. For example, a co-extrusion molding method in which lamination is performed using a feed block method or a multi-manifold method is advantageously employed. Moreover, as a method of obtaining a laminated film, a thermoplastic resin film and a mixed resin film made of a methyl methacrylate-styrene copolymer resin and a polycarbonate resin are respectively produced, and both films are heated using an adhesive or the like. Examples thereof include a laminating method and a coating method in which a thermoplastic resin is formed into a film by an extrusion method or the like, and a methyl methacrylate-styrene copolymer and a polycarbonate resin are dissolved in a solvent if necessary and coated on the surface of the film.

  In addition, the mixed resin composed of methyl methacrylate-styrene copolymer resin and polycarbonate resin has other components as necessary, for example, an ultraviolet absorber, an organic dye, an inorganic dye, a pigment, an antioxidant, an antistatic agent. You may mix | blend an agent, surfactant, etc.

  In order to develop a mat-like design, organic or inorganic fine particles are blended into a mixed resin composed of a methyl methacrylate-styrene copolymer (MS) resin and a polycarbonate resin, and the surface layer is formed as a mat layer. It is effective to do. Examples of the organic fine particles include cross-linked acrylic polymer particles and cross-linked styrene polymer particles, and examples of the inorganic fine particles include silica and alumina. The amount of the fine particles used is appropriately adjusted depending on the desired surface gloss, but is usually about 0.1 to 50% by weight based on the total material constituting the surface layer.

  The thermoplastic resin, which is the constituent material of the base material layer described above, and the mixed resin composed of the methyl methacrylate-styrene copolymer resin and the polycarbonate resin, which are constituent materials of the surface layer, are formed into a laminated film, thereby forming a thermoplastic resin. By forming a surface layer made of methyl methacrylate-styrene copolymer resin and polycarbonate resin on at least one surface of the resulting base material layer, the laminated film of the present invention is obtained.

  The thickness of the laminated film thus obtained is usually 20 to 500 μm, preferably 50 to 250 μm, more preferably 60 to 200 μm, and further preferably 75 to 150 μm. When the laminated film is too thick, for example, when it is molded as an automobile interior material, it takes time for the molding process, and the effect of improving physical properties and design properties is small, and the cost is high. On the other hand, for a very thin laminated film, for example, film formation by extrusion molding becomes difficult due to mechanical restrictions, and the breaking strength is reduced, so that the probability of production failure is increased. In addition, handling of the film itself becomes difficult. For example, in the case of coextrusion molding, the thickness of the laminated film can be adjusted by adjusting the film forming speed, the thickness of the T-die discharge port, the gap between the rolls, and the like.

  The base material layer made of a thermoplastic resin preferably has a thickness of 0.5 times or more of the total thickness of the laminated film. If the base material layer is too thin, that is, if the surface layer made of the mixed resin is thick, the handleability of the film itself deteriorates and the cost of the film itself increases. Further, the surface layer made of the mixed resin preferably has a thickness of 1 to 100 μm. If the surface layer is too thin, the lactic acid resistance is insufficient, and if it is too thick, the handleability of the film itself is deteriorated and the cost of the film itself is increased. The thickness of the surface layer is preferably 3 μm or more, more preferably 10 μm or more, and preferably 75 μm or less, more preferably 50 μm or less. In addition, what is necessary is just to let the thickness of each surface layer be the said predetermined range, when arrange | positioning a surface layer on both surfaces of a base material layer. Further, if the laminated film as a whole is not matte, the haze is preferably 2% or less, and the total light transmittance is preferably 90% or more. When the thickness of the surface layer is 10 μm or more, a coextrusion molding method is advantageously employed as a method for forming a laminated film, and when the thickness of the surface layer is about 1 to 10 μm, as a method for forming a laminated film A coating method is advantageously employed.

  The laminated film of the present invention is preferably used as a decorative film. In this case, a film in which a surface layer is laminated on one surface of a base material layer is preferably used. And it is advantageous to print on the surface opposite to the surface on which the surface layer is laminated as a decorating means, and as the method, for example, continuous gravure printing or silk printing on the surface of the base material layer. Examples thereof include a method for direct printing and a method for laminating other resin films on which printing has been performed.

  Moreover, this decorative film can also be made into a decorative sheet by laminating a thermoplastic resin sheet as a backing material on the printed surface. Here, examples of the resin constituting the thermoplastic resin sheet include ABS resin, methacrylic resin, polyvinyl chloride resin, polyurethane resin, polyester resin, and polyolefin resin. Further, the thickness of the thermoplastic resin sheet includes the thickness of the so-called film region, and is usually about 0.2 to 2 mm.

  And by laminating the decorative film or the decorative sheet thus obtained on the thermoplastic resin molded product so that the surface layer made of the mixed resin is arranged on the front side, that is, with the decorative film If there is, the thermoplastic resin molded product is laminated on the printed surface, and if it is a decorative sheet, the thermoplastic resin molded product is laminated on the surface on which the thermoplastic resin sheet is laminated. By doing so, a decorative molded product having excellent lactic acid resistance can be obtained. Here, examples of the resin constituting the thermoplastic resin molded article include ABS resin, methacrylic resin, polyvinyl chloride resin, polyurethane resin, polyester resin, and polyolefin resin.

  As a method for obtaining a decorative molded product, an injection molding simultaneous bonding method is advantageously employed. The injection molding simultaneous laminating method is, for example, inserting the above film or sheet into an injection mold without pre-molding, and injecting a molten resin therein to form an injection molded product, and at the same time, add the above to the molded product. A method of pasting the film or sheet (sometimes referred to as narrow-injection simultaneous molding method), the above film or sheet is preformed by vacuum molding or pressure molding, and then inserted into an injection mold. A method of injecting a molten resin there to form an injection-molded product and simultaneously bonding the film or sheet to the molded product (sometimes called an insert molding method), injection-molding the film or sheet After preforming in a mold by vacuum molding or pressure molding, etc., a molten resin is injected there to form an injection-molded product, and at the same time, the above film or sheet is applied to the molded product. Preparative (sometimes referred to as in-mold molding method) methods of bonding may be performed by such. More detailed explanation of the simultaneous injection molding method is described in, for example, Japanese Patent Publication No. 63-6339, Japanese Patent Publication No. 4-9647, Japanese Patent Application Laid-Open No. 7-9484, and the like.

  Examples of the present invention will be described below, but the present invention is not limited thereto. In the examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified.

  As the methacrylic resin, pellets of a thermoplastic polymer (glass transition temperature 104 ° C.) obtained by bulk polymerization of a monomer composed of 97.8% methyl methacrylate and 2.2% methyl acrylate were used. This glass transition temperature is an extrapolated glass transition start temperature obtained at a heating rate of 10 ° C./min by differential scanning calorimetry according to JIS K7121: 1987.

  As the acrylic rubber particles (A), the innermost layer is a hard polymer obtained by polymerization of a monomer composed of 93.8% methyl methacrylate, 6% methyl acrylate, and 0.2% allyl methacrylate, The intermediate layer is an elastic polymer obtained by polymerization of a monomer composed of 81% butyl acrylate, 17% styrene and 2% allyl methacrylate, and the outermost layer is 94% methyl methacrylate and 6% methyl acrylate. The weight ratio of the innermost layer / intermediate layer / outermost layer is 35/45/20, and the average particle diameter of the elastic polymer layer of the intermediate layer A rubber particle having a spherical three-layer structure by an emulsion polymerization method having a particle size of 0.22 μm was used.

  The acrylic rubber particles (B) have basically the same composition as the acrylic rubber particles (A), but by changing the polymerization conditions, the average particle diameter of the elastic polymer layer of the intermediate layer becomes 0.14 μm. Rubber particles having a spherical three-layer structure were used.

  As the acrylic rubber particles (C), the inner layer is an elastic polymer obtained by polymerization of a monomer composed of 81% butyl acrylate, 17% styrene, and 2% allyl methacrylate, and the outer layer is 94% methyl methacrylate. Is a hard polymer obtained by polymerization of a monomer consisting of 6% of methyl acrylate, and an elastic polymer layer of the intermediate layer having an average particle size of 0.075 μm, and a spherical two-layer by emulsion polymerization method Structured rubber particles were used.

  In addition, the average particle diameter of the elastic polymer layer of the intermediate layer in the acrylic rubber particles (A), (B), and (C) was measured by the following method.

(Measurement of average particle diameter of elastic polymer layer)
Acrylic rubber particles are mixed with a methacrylic resin to form a film, and the resulting film is cut into an appropriate size, and the slice is immersed in a 0.5% aqueous ruthenium tetroxide solution at room temperature for 15 hours. The polymer layer was dyed. Further, the sample was cut to a thickness of about 80 nm using a microtome, and then photographed with a transmission electron microscope. After randomly selecting 100 dyed elastic copolymer layers from this photograph and calculating the particle diameter of each, the number average value was taken as the average particle diameter.

  As the methyl methacrylate-styrene copolymer resin (a), a resin having 5% by weight of methyl methacrylate units and 95% by weight of styrene units was used. Hereinafter, it is abbreviated as MS resin (a).

  As the methyl methacrylate-styrene copolymer resin (b), a resin having 3% by weight of methyl methacrylate units and 97% by weight of styrene units was used. Hereinafter, it is abbreviated as MS resin (b).

  As the methyl methacrylate-styrene copolymer resin (c), a resin having 60% by weight of methyl methacrylate units and 40% by weight of styrene units was used. Hereinafter, it is abbreviated as MS resin (c).

As the polycarbonate resin, Caliber 301-10 manufactured by Sumitomo Dow Co., Ltd. was used. The molecular weight of the polycarbonate resin is 43000 in weight average, melt volume flow rate is 300 ° C., 10 at 1.2kg load (cm ^3/10 min). Hereinafter, it is abbreviated as PC resin.

Examples 1-10
The above methacrylic resin pellets and acrylic rubber particles (A), (B) or (C) are mixed at a ratio shown in Table 1 with a supermixer and melt kneaded with a twin screw extruder to obtain a methacrylic resin composition. Pellets. Further, the above MS resin (a), (b) or (c) and PC resin are mixed at a ratio shown in Table 1 with a super mixer, melt-kneaded with a twin screw extruder, and mixed resin. It was set as a pellet. Next, the pellets of the methacrylic resin composition were melted with a 65 mmφ single screw extruder manufactured by Toshiba Machine Co., Ltd., and the pellets of the mixed resin were melted with a 45 mmφ single screw extruder manufactured by Toshiba Machine Co., Ltd. The layers were integrated and extruded through a T-shaped die having a set temperature of 275 ° C., and the resulting film was sandwiched between a pair of metal rolls with smooth surfaces and molded. In this way, a laminated film having a two-layer structure shown in Table 1 was produced, the following evaluation was performed, and the results are shown in Table 1.

[Lactic acid resistance]
A 10% aqueous solution of lactic acid was prepared, and after dropping one drop on the film surface [mixed resin layer (surface layer) side], the solution was left in an oven at 40 ° C. for 24 hours, and the state was visually confirmed. Those in which droplet traces are clearly confirmed, those in which the film surface is dissolved, or those in which cracks are generated in the film are indicated as ×, those in which slight droplet traces are confirmed are indicated by Δ, and those having no change are indicated by ○. .

〔optical properties〕
The total light transmittance (Tt) and haze (Haze) are measured by the method described in JIS 7136, and the difference between the refractive index (η1) of the MS resin and the refractive index (η2) of the PC resin (Δη = η1− This is shown together with η2).

〔appearance〕
The case where the occurrence of a flow mark was remarkable at the time of film formation was evaluated as x, the case where a flow mark was generated slightly was evaluated as Δ, and the case where no flow mark was confirmed was evaluated as ○.

Comparative Example 1
The above methacrylic resin pellets and acrylic rubber particles (A) were mixed at a ratio shown in Table 1 with a super mixer, and melt-kneaded with a twin screw extruder to obtain pellets of a methacrylic resin composition. Next, the methacrylic resin composition pellets were melted with a 65 mmφ single screw extruder manufactured by Toshiba Machine Co., Ltd. and extruded through a T-shaped die with a set temperature of 275 ° C., and the resulting film-like product was smoothed on a pair of surfaces. The metal roll was sandwiched and formed. Thus, a single-layer acrylic film having the thickness shown in Table 1 was produced, and the same evaluation as above was performed. The results are shown in Table 1.

Claims (18)

When a surface layer made of a methyl methacrylate-styrene copolymer resin and a polycarbonate resin is laminated on at least one surface of a base material layer made of a thermoplastic resin , the surface of a molded product is decorated A laminated film characterized in that the surface layer is located on the outermost surface layer of a molded product decorated .   The laminated film according to claim 1, wherein the methyl methacrylate-styrene copolymer resin has 1 to 30% by weight of methyl methacrylate units and 70 to 99% by weight of styrene units.   The laminated film according to claim 1 or 2, wherein a weight ratio of methyl methacrylate-styrene copolymer resin / polycarbonate resin in the surface layer is 1/20 to 20/1.   The difference (η1-η2) between the refractive index (η1) of the methyl methacrylate-styrene copolymer resin and the refractive index (η2) of the polycarbonate resin in the surface layer is -0.05 to 0.05. 4. The laminated film according to any one of 3.   The total thickness is 20 to 500 µm, the thickness of the base material layer is 0.5 times or more of the total thickness, and the thickness of the surface layer is 1 to 100 µm. A laminated film according to any one of the above.   The laminated film according to any one of claims 1 to 5, wherein the thermoplastic resin is a methacrylic resin.   The methacrylic resin is a polymer obtained by polymerizing 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate, and 0 to 49% by weight of other monomers. 6. The laminated film according to 6.   The laminated film according to claim 1, wherein the base material layer contains rubber particles.   The laminated film according to claim 8, wherein the rubber particles are acrylic rubber particles.   Acrylic rubber particles in a proportion of 50 to 99.9% by weight of alkyl acrylate, 0 to 49.9% by weight of other monofunctional monomers, and 0.1 to 10% by weight of polyfunctional monomers The laminated film according to claim 9, wherein the laminated film is a particle containing an elastic polymer obtained by polymerization.   Acrylic rubber particles have a ratio of 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate, and 0 to 49% by weight of other monomers on the outside of the elastic polymer layer. The laminated film according to claim 10, wherein the laminated film is a particle having a multilayer structure having a polymer layer obtained by polymerization with a polymer.   A polymer layer in which acrylic rubber particles are polymerized at a ratio of 70 to 100% by weight of alkyl methacrylate and 0 to 30% by weight of other monomers inside the elastic polymer layer. The laminated film according to claim 11, which is a particle having a multilayer structure.   The laminated film according to any one of claims 1 to 12, wherein the surface layer contains organic or inorganic fine particles.   The laminated film according to claim 1, wherein the surface layer is laminated on one surface of the base material layer.   The film for decorating characterized by printing on the surface on the opposite side to the surface where the said surface layer of the laminated | multilayer film of Claim 14 was laminated | stacked.   A thermoplastic resin sheet is laminated on the surface on which the decorative film according to claim 15 is printed.   A decorative molded product, wherein a thermoplastic resin molded product is laminated on a surface on which the decorative film according to claim 15 is printed.   A decorative molded product, wherein a thermoplastic resin molded product is laminated on a surface of the decorative sheet according to claim 16 on which the thermoplastic resin sheet is laminated.