JP2010109348A - Solar cell backside protective film, and solar cell module with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell backside protective film which encloses a solar cell element and is excellent in bondability with a filler containing an ethylene-vinyl acetate copolymer composition etc. and whetherability: and to provide a solar cell module with the protective film. <P>SOLUTION: The solar cell backside protective film includes: a resin layer obtained using a thermoplastic resin composition formed by melt-kneading a material composition containing a thermoplastic resin and a silane coupling agent. The solar cell module is with the solar cell backside protective film. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

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

As a back surface protective film for a solar cell, a film containing a fluororesin, a polyethylene resin, a polyester resin, or the like has been conventionally known. However, the adhesiveness to the filler portion and the long-term durability are not sufficient.
Patent Document 1 discloses a solar cell in which a base film made of polyethylene terephthalate is provided with a thermal adhesive layer including a styrene / olefin copolymer having thermal adhesiveness with a polyolefin resin such as an ethylene / vinyl acetate copolymer. A backside sealing film is disclosed.
Patent Document 2 discloses a film in which a coating layer containing a polyurethane-based resin or an organosilane compound is formed on a base film made of polyethylene terephthalate.
Patent Document 3 includes a polyester film containing an ethylene terephthalate unit, and a coating containing a crosslinking agent, a polyester resin having a glass transition point of 20 ° C. to 100 ° C., an acrylic resin, and the like. The polyester film for solar cell back surface protective films provided with the coated film was disclosed.

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

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

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

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

The present invention is shown below.
1. A thermoplastic resin composition (hereinafter referred to as “first thermoplastic resin composition”) obtained by melt kneading a raw material composition containing a thermoplastic resin (hereinafter also referred to as “first thermoplastic resin”) and a silane coupling agent. The back surface protective film for solar cells, comprising a resin layer (hereinafter, also referred to as “first resin layer”) obtained by using the same.
2. 2. When the light of wavelength 400-1400 nm is radiated | emitted on the surface of the said resin layer (1st resin layer) in the said back surface protective film for solar cells, the reflectance with respect to this light is 50% or more of said 1 Back surface protection film for solar cells.
3. 3. The back protective film for solar cell according to 1 or 2 above, wherein the thermoplastic resin composition (first thermoplastic resin composition) further contains a white colorant.
4). 2. The resin layer (first resin layer) according to 1 above, wherein the transmittance for light having a wavelength of 800 to 1,400 nm is 60% or more and the absorptance for light having a wavelength of 400 to 700 nm is 60% or more. Back surface protective film for solar cells.
5). 5. The back surface protective film for solar cell according to 4 above, wherein the thermoplastic resin composition (first thermoplastic resin composition) further contains an infrared transmitting colorant.
6). The back protective film for a solar cell according to any one of 1 to 5, wherein the thermoplastic resin (first thermoplastic resin) contains a rubber-reinforced aromatic vinyl resin.
7). Furthermore, the back surface protective film for solar cells in any one of said 1 thru | or 6 provided with the other resin layer joined to the said resin layer (1st resin layer).
8). 8. The back surface protective film for solar cell as described in 7 above, wherein the other resin layer is a white resin layer.
9. The back surface protective film for solar cells according to any one of 1 to 8 above, wherein the thickness is 10 to 1,000 μm.
10. A solar cell module comprising the solar cell back surface protective film according to any one of 1 to 9 above.

According to the back surface protective film for a solar cell of the present invention, the first resin obtained by using the first thermoplastic resin composition obtained by melt-kneading the raw material composition containing the first thermoplastic resin and the silane coupling agent. Since the layer is provided, this first resin layer is excellent in adhesiveness, heat resistance and weather resistance between the first resin layer and the filler part including the ethylene / vinyl acetate copolymer composition which embeds the solar cell element. Therefore, a solar cell module in which the filler part is reliably protected can be provided.
When light having a wavelength of 400 to 1,400 nm is radiated to the surface of the first resin layer in the back surface protective film for solar cells, the first resin has a reflectance of 50% or more. The layer is highly reflective to sunlight, so that when sunlight leaks from the gap between adjacent solar cell elements toward the back surface protective film for solar cells, the reflected light is supplied to the back surface of the solar cell elements. Thus, it can be used for photoelectric conversion to improve power generation efficiency.
Further, when the first thermoplastic resin composition further contains a white colorant, the first resin layer is particularly excellent in reflectivity for sunlight. Therefore, not only in the case of a single layer type film, but also in the case of a laminated film having the first resin layer and another resin layer, etc., depending on the purpose and application, and the filler portion and surface in the first resin layer Even when the member is disposed on the non-side, the effect of improving the power generation efficiency is excellent regardless of the configuration of other resin layers and the like.

In the first resin layer, when the transmittance with respect to light with a wavelength of 800 to 1,400 nm is 60% or more and the absorption with respect to light with a wavelength of 400 to 700 nm is 60% or more, sunlight is When the first resin layer leaks from the gap between adjacent solar cell elements toward the solar cell back surface protective film, heat storage due to light having the wavelength of 800 to 1,400 nm is suppressed. The heat storage of the filler part adhering to the layer is also suppressed. And the thermal storage in the solar cell module formed using this film is suppressed, and the deformation | transformation of structural members including a film and the fall of electric power generation efficiency can be suppressed. When a member having excellent light reflectivity is disposed on the side of the first resin layer that does not face the filler portion, the light transmitted through the first resin layer is reflected from the surface of the member. Then, the reflected light can be supplied to the back surface of the solar cell element and used for photoelectric conversion to improve power generation efficiency. Moreover, the back surface protective film for solar cells of this invention is a laminated film provided with the 1st resin layer which has this property, and another resin layer as said member, Comprising: Other resin layers are white resin layers. In this case, the same effect can be surely obtained.
When the first thermoplastic resin composition further contains an infrared transmitting colorant, the first resin layer has a transmittance of 60% or more for light having a wavelength of 800 to 1,400 nm, and The solar cell module which has the property that the absorptivity with respect to the light with a wavelength of 400-700 nm is 60% or more, and has the outstanding dark color type external appearance can be given. And when sunlight hits a film, not only the deformation of the structural members including the film and the decrease in power generation efficiency are suppressed, but also the solar cell provided with the back surface protective film for solar cell of the present invention, When placed on a roof or the like, the appearance of the solar cell is excellent. Furthermore, the back surface protective film for solar cells of the present invention is a laminated film comprising a first resin layer containing an infrared transmitting colorant and another resin layer, and the other resin layer is a white resin layer. In this case, heat storage in the first resin layer and its deformation are suppressed, heat storage in the solar cell module is suppressed, and the effect of improving power generation efficiency is excellent.

  When the first thermoplastic resin contains a rubber-reinforced aromatic vinyl resin, it is excellent in hydrolysis resistance, dimensional stability, impact resistance and the like of the back protective film for solar cells.

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

It is a schematic sectional drawing which shows an example of the back surface protection film for solar cells of this invention (single layer type). It is a schematic sectional drawing which shows an example of the back surface protection film (lamination type) for solar cells of this invention. It is a schematic sectional drawing which shows the other example of the back surface protection film for solar cells of this invention (lamination | stacking type). It is a schematic sectional drawing which shows an example of the solar cell module of this invention.

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

  The back surface protective film for a solar cell of the present invention is a thermoplastic resin composition (in which a raw material composition containing a thermoplastic resin (hereinafter also referred to as “first thermoplastic resin”) and a silane coupling agent is melt-kneaded ( Hereinafter, it is characterized by comprising a resin layer (hereinafter referred to as “first resin layer”) obtained by using “first thermoplastic resin composition”.

The solar cell back surface protective film of the present invention may be a single-layer film 1A having only the first resin layer (see FIG. 1), the first resin layer 11 and the first resin layer 11. It may be a laminated film (including a laminated sheet) 1B including another layer 15 joined (see FIGS. 2 and 3). The other layer 15 will be described later.
In the present invention, the back protective film for a solar cell is a surface of the first resin layer to adhere to the exposed surface of the filler part of the solar cell module, whether it is a single layer film or a laminated film. Used.

The first resin layer is a layer obtained by using a first thermoplastic resin composition obtained by melt-kneading a raw material composition containing a first thermoplastic resin and a silane coupling agent. Since the back surface protective film for solar cells of the present invention can be a single-layer film composed of only the first resin layer as described above, the first thermoplastic resin composition is preferably film-forming. It is a composition which has this.
The glass transition temperature (hereinafter referred to as “Tg”) of the first resin layer is preferably 100 ° C. to 220 ° C., more preferably 110 ° C. to 200 ° C. When the glass transition temperature Tg is in the above range, the heat resistance is excellent. The glass transition temperature can be measured by a differential scanning calorimeter (DSC).

The first thermoplastic resin contained in the raw material composition is not particularly limited as long as it is a resin having thermoplasticity; rubber-reinforced aromatic vinyl resins such as ABS resin, ASA resin, AES resin; Aromatic vinyl (co) polymers such as polymers (AS resins); Acrylic resins such as (co) polymers using one or more (meth) acrylic acid ester compounds such as polymethyl methacrylate; Vinyl chloride resins such as vinyl chloride; Vinylidene chloride resins such as polyvinylidene chloride; Polyamide resins; Polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; Polyethylene, polypropylene, ethylene / vinyl acetate copolymer , Ethylene / vinyl chloride copolymer, ethylene / vinyl alcohol copolymer , Olefin resin ionomers; polycarbonate resins; polyarylate resin; polyvinyl acetate, and the like. These can be used alone or in combination of two or more.
As said 1st thermoplastic resin, rubber-reinforced aromatic vinyl-type resin, polyester-type resin, and olefin-type resin are preferable, and rubber-reinforced aromatic vinyl-type resin is especially preferable. When the first thermoplastic resin contains a rubber-reinforced aromatic vinyl resin, it is excellent in hydrolysis resistance, dimensional stability, impact resistance, and the like.

The rubber-reinforced aromatic vinyl resin is usually a monomer containing an aromatic vinyl compound in the presence of a rubbery polymer (hereinafter also referred to as “rubbery polymer (a)”). In the absence of the copolymer resin (A11) obtained by polymerizing the vinyl monomer (b1) ”) or the copolymer resin (A11) and the rubbery polymer, aromatic vinyl is obtained. It is a mixture with an aromatic vinyl (co) polymer (A12) obtained by polymerizing a monomer containing a compound (hereinafter referred to as “vinyl monomer (b2)”).
The content of the rubbery polymer (a) contained in the rubber-reinforced aromatic vinyl resin is preferably 1 to 55% by mass, more preferably 5 to 40% by mass. If the content of the rubbery polymer (a), the first resin layer to be obtained has adhesiveness to a filler part embedding a solar cell element, hydrolysis resistance, dimensional stability, and impact resistance. Etc.

The rubbery polymer (a) is not particularly limited as long as it is rubbery at room temperature, and may be a homopolymer or a copolymer. The rubbery polymer (a) may be a crosslinked polymer or a non-crosslinked polymer.
In the present invention, the rubbery polymer (a) is preferably a diene polymer or a non-diene polymer. These polymers can be used alone or in combination of two or more.

  Examples of the diene polymer include homopolymers such as polybutadiene and polyisoprene; styrene / butadiene copolymer rubbers; styrene / isoprene copolymer rubbers; natural rubbers and the like. These copolymers may be block copolymers or random copolymers. These copolymers may be hydrogenated (however, the hydrogenation rate is less than 50%). The said diene polymer can be used individually by 1 type or in combination of 2 or more types.

  Examples of the non-diene polymer include ethylene units and ethylene / α-olefin copolymer rubbers containing structural units derived from α-olefins having 3 or more carbon atoms; urethane rubbers; acrylic rubbers; silicones Rubber; Silicone / acrylic composite rubber; Polymer obtained by hydrogenating a (co) polymer containing a structural unit derived from a conjugated diene compound (however, the hydrogenation rate is usually 50% or more). It is done. These copolymers may be block copolymers or random copolymers. The non-diene polymer is preferably an acrylic rubber from the viewpoint of weather resistance. Moreover, the said non-diene polymer can be used individually by 1 type or in combination of 2 or more types.

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

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

  When the acrylic rubber contains a structural unit derived from another monomer, other monomers include vinyl chloride, vinylidene chloride, acrylonitrile, vinyl ester, methacrylic acid alkyl ester, (meth) acrylic acid, Monofunctional monomers such as styrene; mono- or polyethylene glycol di (such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate ( Di- or triallyl compounds such as (meth) acrylate, divinylbenzene, diallyl phthalate, diallyl maleate, diallyl succinate, triallyl triazine, allyl compounds such as allyl (meth) acrylate, conjugated diene compounds such as 1,3-butadiene Crosslinkable monomer, etc. and the like.

The acrylic rubber preferably has a Tg of -10 ° C or lower. Therefore, the acrylic rubber preferable in the present invention is preferably a copolymer containing a structural unit derived from the crosslinkable monomer.
The content of the structural unit derived from the crosslinkable monomer constituting the preferred acrylic rubber is preferably 0.01 to 10% by mass, more preferably 0.05 to 8% by mass with respect to the total amount of the structural unit. %, More preferably 0.1 to 5% by mass.

  The shape of the rubber polymer (a) is not particularly limited, but when it is particulate, the volume average particle diameter is preferably 50 to 2,000 nm, more preferably 70 to 1,500 nm. When the volume average particle diameter is in the above range, the processability of the first thermoplastic resin composition and the impact resistance of the obtained first resin layer are excellent. The volume average particle diameter can be measured by an image analysis method using an electron micrograph, a laser diffraction method, a light scattering method, or the like.

  When the rubbery polymer (a) is in the form of particles, as long as the volume average particle diameter is within the above range, for example, JP-A-61-233010, JP-A-59-93701, JP The thing enlarged by the well-known method described in 56-167704 gazette etc. can also be used.

  As a method for producing the rubbery polymer (a), emulsion polymerization is preferable in consideration of adjustment of the average particle diameter and the like. In this case, the average particle size can be adjusted by selecting the production conditions such as the type of emulsifier and the amount used, the type and amount of initiator used, the polymerization time, the polymerization temperature, and the stirring conditions. Further, as another method for adjusting the average particle size (particle size distribution), a method of blending two or more of the rubbery polymers (a) having different particle sizes may be used.

  As described above, the vinyl monomer (b1) used for forming the copolymer resin (A11) constituting the rubber-reinforced aromatic vinyl resin contains an aromatic vinyl compound. This vinyl monomer (b1) may be only an aromatic vinyl compound or a combination of this aromatic vinyl compound and another monomer. Other monomers include vinyl cyanide compounds, (meth) acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, carboxyl group-containing unsaturated compounds, hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds Examples thereof include compounds, amide group-containing unsaturated compounds, epoxy group-containing unsaturated compounds, and oxazoline group-containing unsaturated compounds. These can be used alone or in combination of two or more.

  The aromatic vinyl compound is not particularly limited as long as it is a compound having at least one vinyl bond and at least one aromatic ring. Examples thereof include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, β-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinyltoluene, vinylxylene, vinylnaphthalene, monochlorostyrene, dichloromethane. Examples thereof include styrene, monobromostyrene, dibromostyrene, tribromostyrene, and fluorostyrene. These compounds can be used alone or in combination of two or more. Of these, styrene and α-methylstyrene are preferable, and styrene is particularly preferable.

  Examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile, ethacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-chloroacrylonitrile, α-fluoroacrylonitrile and the like. Of these, acrylonitrile is preferred. Moreover, these compounds can be used individually or in combination of 2 or more.

  Examples of the (meth) acrylate compound include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Examples include cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, and the like. These compounds can be used alone or in combination of two or more.

  Examples of the maleimide compound include maleimide, N-methylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-dodecylmaleimide, N-phenylmaleimide, N- (2-methylphenyl) maleimide, N- (4-methyl). Phenyl) maleimide, N- (2,6-dimethylphenyl) maleimide, N- (2,6-diethylphenyl) maleimide, N- (2-methoxyphenyl) maleimide, N-benzylmaleimide, N- (4-hydroxyphenyl) ) Maleimide, N-naphthylmaleimide, N-cyclohexylmaleimide and the like. Of these, N-phenylmaleimide is preferred. Moreover, these compounds can be used individually or in combination of 2 or more. As another method for introducing a structural unit derived from a maleimide compound into the rubber-reinforced aromatic vinyl resin, for example, an unsaturated dicarboxylic anhydride of maleic anhydride is copolymerized and then imidized. The method may be used.

Examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, and the like. These compounds can be used alone or in combination of two or more.
Examples of the carboxyl group-containing unsaturated compound include (meth) acrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, cinnamic acid and the like. These compounds can be used alone or in combination of two or more.

  Examples of the hydroxyl group-containing unsaturated compound include 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (Meth) acrylic acid 2-hydroxybutyl, (meth) acrylic acid 3-hydroxybutyl, (meth) acrylic acid 4-hydroxybutyl, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, (meth) acrylic (Meth) acrylic acid ester having a hydroxyl group such as a compound obtained by adding ε-caprolactone to 2-hydroxyethyl acid; o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, o-hydroxy-α -Methylstyrene M-hydroxy-α-methylstyrene, p-hydroxy-α-methylstyrene, 2-hydroxymethyl-α-methylstyrene, 3-hydroxymethyl-α-methylstyrene, 4-hydroxymethyl-α-methylstyrene, 4 -Hydroxymethyl-1-vinylnaphthalene, 7-hydroxymethyl-1-vinylnaphthalene, 8-hydroxymethyl-1-vinylnaphthalene, 4-hydroxymethyl-1-isopropenylnaphthalene, 7-hydroxymethyl-1-isopropenylnaphthalene 8-hydroxymethyl-1-isopropenylnaphthalene, p-vinylbenzyl alcohol and the like. These compounds can be used alone or in combination of two or more.

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

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

  Examples of the epoxy group-containing unsaturated compound include glycidyl (meth) acrylate, 3,4-oxycyclohexyl (meth) acrylate, vinyl glycidyl ether, allyl glycidyl ether, and methallyl glycidyl ether. These compounds can be used alone or in combination of two or more.

Moreover, as other monomers, a vinyl cyanide compound and a maleimide compound are preferable, and it is particularly preferable that a vinyl cyanide compound is included. As the vinyl cyanide compound, acrylonitrile is preferred. As the maleimide compound, N-phenylmaleimide is preferable.
When the vinyl monomer (b1) contains an aromatic vinyl compound and a vinyl cyanide compound, the total amount thereof is preferably 70 to 100 mass with respect to the entire vinyl monomer (b1). %, More preferably 80 to 100% by mass. Further, the use ratio of the aromatic vinyl compound and the vinyl cyanide compound is preferably 5 to 95% by mass, respectively, from the viewpoint of hydrolysis resistance, molding processability and toughness, when the total of these is 100% by mass. And 5 to 95 mass%, more preferably 20 to 90 mass% and 10 to 80 mass%, still more preferably 30 to 85 mass% and 15 to 70 mass%.
When the vinyl monomer (b1) is composed of an aromatic vinyl compound, a vinyl cyanide compound and a maleimide compound, the use ratio of these compounds is hydrolysis resistance, chemical resistance, heat resistance, etc. From the viewpoint of the above, when these totals are 100% by mass, preferably 20 to 90% by mass, 5 to 45% by mass and 1 to 50% by mass, more preferably 30 to 85% by mass and 10 to 40% by mass, respectively. % And 2 to 40% by mass, more preferably 40 to 80% by mass, 15 to 35% by mass and 3 to 30% by mass.

As the copolymer resin (A11) constituting the rubber-reinforced aromatic vinyl resin, preferred resins are as follows.
[1] Copolymer resin obtained by polymerizing vinyl monomer (b1) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of rubber polymer (a) [2] Rubber weight Copolymer resin [3] rubbery polymer (3) obtained by polymerizing a vinyl monomer (b1) comprising an aromatic vinyl compound, a vinyl cyanide compound and a maleimide compound in the presence of the compound (a). a copolymer resin obtained by polymerizing a vinyl monomer (b1) comprising an aromatic vinyl compound, a vinyl cyanide compound and a methacrylate ester compound in the presence of a)

  The copolymer resin (A11) can be produced by polymerizing the vinyl monomer (b1) in the presence of the rubber polymer (a). As the polymerization method, emulsion polymerization, solution polymerization, bulk polymerization, and bulk-suspension polymerization are preferable.

  In the production of the copolymer resin (A11), the rubber polymer (a) and the vinyl monomer (b1) are present in the reaction system in the total amount of the rubber polymer (a). Below, the said vinyl-type monomer (b1) may be added collectively, and superposition | polymerization may be started, or you may superpose | polymerize, dividing | segmenting or adding continuously. Further, in the presence or absence of part of the rubber polymer (a), the vinyl monomer (b1) may be added all at once to initiate polymerization, or may be divided or continuously. May be added. At this time, the remainder of the rubbery polymer (a) may be added in a batch, divided or continuously during the reaction.

  When manufacturing 100 mass parts of said copolymer resins (A11), the usage-amount of the said rubber-like polymer (a) is 10-70 mass parts normally. Moreover, the usage-amount of the said vinyl-type monomer (b1) is 43-900 mass parts normally with respect to 100 mass parts of said rubber-like polymers (a).

  When the copolymer resin (A11) is produced by emulsion polymerization, a polymerization initiator, a chain transfer agent (molecular weight regulator), an emulsifier, water and the like are used.

As the polymerization initiator, a redox in which an organic peroxide such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, or the like and a reducing agent such as a sugar-containing pyrophosphate formulation or a sulfoxylate formulation are combined. System initiators; persulfates such as potassium persulfate; peroxides such as benzoyl peroxide (BPO), lauroyl peroxide, tert-butyl peroxylaurate, and tert-butyl peroxymonocarbonate. These can be used alone or in combination of two or more. Moreover, the usage-amount of the said polymerization initiator is 0.1-1.5 mass% normally with respect to the said vinylic monomer (b1) whole quantity.
The polymerization initiator can be added to the reaction system all at once or continuously.

Examples of the chain transfer agent include octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-hexyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, tert-tetradecyl mercaptan, and other mercaptans; Examples include α-methylstyrene dimers. These can be used alone or in combination of two or more. The amount of the chain transfer agent used is usually 0.05 to 2.0% by mass with respect to the total amount of the vinyl monomer (b1).
The chain transfer agent can be added to the reaction system all at once or continuously.

  Examples of the emulsifier include anionic surfactants and nonionic surfactants. Anionic surfactants include higher alcohol sulfates; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; aliphatic sulfonates such as sodium lauryl sulfate; higher aliphatic carboxylates, aliphatic phosphates, etc. Is mentioned. Examples of nonionic surfactants include polyethylene glycol alkyl ester compounds and alkyl ether compounds. These can be used alone or in combination of two or more. The usage-amount of the said emulsifier is 0.3-5.0 mass% normally with respect to the said vinylic monomer (b1) whole quantity.

Emulsion polymerization can be carried out under known conditions depending on the type of vinyl monomer (b1), polymerization initiator, and the like. The latex obtained by this emulsion polymerization is usually purified by coagulation with a coagulant to form a polymer component in powder form, and then washing and drying the polymer component. Examples of the coagulant include inorganic salts such as calcium chloride, magnesium sulfate, magnesium chloride, and sodium chloride; inorganic acids such as sulfuric acid and hydrochloric acid; organic acids such as acetic acid and lactic acid.
In addition, when the rubber-reinforced aromatic vinyl-based resin contains two or more copolymer resins (A11), the resin may be isolated from each latex and then mixed, but as another method, There are methods such as coagulating a latex mixture containing each resin.

  A known method can be applied to the method for producing the copolymer resin (A11) by solution polymerization, bulk polymerization, and bulk-suspension polymerization.

  The rubber-reinforced aromatic vinyl resin containing the copolymer resin (A11) obtained when a diene polymer is used as the rubber polymer (a) is generally referred to as “ABS resin”. The rubber-reinforced aromatic vinyl resin containing a copolymer resin (A11) obtained when an ethylene / α-olefin copolymer rubber is used as the rubber polymer (a) is generally “ It is said to be “AES resin”. The rubber-reinforced aromatic vinyl resin containing the copolymer resin (A11) obtained when acrylic rubber is used as the rubber polymer (a) is generally referred to as “ASA resin”.

  The graft ratio of the copolymer resin (A11) is preferably 20 to 170% by mass, more preferably 30 to 170% by mass, and still more preferably 40 to 150% by mass. If the graft ratio is too low, the flexibility of the first resin layer obtained using the first thermoplastic resin composition may not be sufficient. On the other hand, if the graft ratio is too high, the viscosity of the first thermoplastic resin composition becomes high, and it may be difficult to reduce the thickness.

The graft ratio can be determined by the following formula.
Graft ratio (mass%) = {(S−T) / T} × 100
In the above formula, S represents 1 gram of rubber-reinforced aromatic vinyl resin in 20 ml of acetone (acetonitrile when the rubbery polymer is an acrylic rubber) and shaken at 25 ° C. with a shaker for 2 hours. After that, the mass (gram) of insoluble matter obtained by centrifuging at 5 ° C. for 60 minutes with a centrifuge (rotation speed: 23,000 rpm) to separate the insoluble matter and the soluble matter. Is the mass (grams) of the rubbery polymer contained in 1 gram of rubber-reinforced aromatic vinyl resin. The mass of the rubbery polymer can be obtained by a method of calculating from a polymerization prescription and a polymerization conversion rate, a method of obtaining from an infrared absorption spectrum (IR), and the like.

The said copolymer resin (A11) can be used individually by 1 type or in combination of 2 or more types.
As the rubber-reinforced aromatic vinyl resin, ABS resin, ASA resin and AES resin are preferable, ABS resin and ASA resin are more preferable, and ASA resin is particularly preferable.

  Next, when the rubber-reinforced aromatic vinyl resin is a mixture of the copolymer resin (A11) and the aromatic vinyl (co) polymer (A12), this aromatic vinyl (co) polymer. (A12) is not particularly limited as long as it is a (co) polymer obtained by polymerizing a vinyl monomer (b2) containing an aromatic vinyl compound in the absence of a rubbery polymer. That is, the aromatic vinyl (co) polymer (A12) may be either a homopolymer or a copolymer, or a combination thereof.

  The vinyl monomer (b2) may be an aromatic vinyl compound alone or a combination of this aromatic vinyl compound and another monomer. Other monomers include vinyl cyanide compounds, (meth) acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, carboxyl group-containing unsaturated compounds, hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds Examples thereof include compounds, amide group-containing unsaturated compounds, epoxy group-containing unsaturated compounds, and oxazoline group-containing unsaturated compounds. These can be used alone or in combination of two or more.

The aromatic vinyl (co) polymer (A12) is preferably a copolymer. In the present invention, the vinyl monomer (b2) is preferably composed of an aromatic vinyl compound and another monomer. Other monomers are preferably vinyl cyanide compounds and maleimide compounds.
When the vinyl monomer (b2) contains an aromatic vinyl compound and a vinyl cyanide compound, the total amount thereof is preferably 70 to 100 mass with respect to the entire vinyl monomer (b2). %, More preferably 80 to 100% by mass. In addition, the use ratio of the aromatic vinyl compound and the vinyl cyanide compound is preferably 5 to 95% by mass and 100% by mass, respectively, from the viewpoint of hydrolysis resistance, chemical resistance and the like. 5 to 95% by mass, more preferably 50 to 95% by mass and 5 to 50% by mass, still more preferably 60 to 95% by mass and 5 to 40% by mass, particularly preferably 65 to 85% by mass and 15 to 35% by mass. It is.

When the aromatic vinyl-based (co) polymer (A12) is a copolymer, preferred polymers are as follows.
[1] A structural unit derived from an aromatic vinyl compound (hereinafter referred to as “structural unit (s)”) and a structural unit derived from a vinyl cyanide compound (hereinafter referred to as “structural unit (t)”). [2] a structural unit (s) derived from an aromatic vinyl compound, a structural unit (t) derived from a vinyl cyanide compound, and a structural unit derived from a maleimide compound (hereinafter referred to as “structural unit”). (U) ")))

When the aromatic vinyl-based (co) polymer (A12) is in the above embodiment [1], the content ratio of the structural unit (s) and the structural unit (t) is in view of hydrolysis resistance, chemical resistance, and the like. Therefore, when the total of these is 100% by mass, preferably 5 to 95% by mass and 5 to 95% by mass, more preferably 50 to 95% by mass and 5 to 50% by mass, and still more preferably 60 to 95%, respectively. They are mass% and 5-40 mass%, Most preferably, they are 65-85 mass% and 15-35 mass%.
Examples of the copolymer of the above embodiment [1] include acrylonitrile / styrene copolymer, acrylonitrile / α-methylstyrene copolymer, and the like.

When the aromatic vinyl (co) polymer (A12) is in the above embodiment [2], the content ratio of the structural unit (s), the structural unit (t), and the structural unit (u) is hydrolysis resistance, From the viewpoint of chemical resistance and heat resistance, when these totals are 100% by mass, preferably 20 to 85% by mass, 2 to 50% by mass and 3 to 60% by mass, more preferably 25 to 80% by mass, respectively. %, 4-40% by mass and 5-55% by mass, more preferably 30-75% by mass, 5-35% by mass and 10-50% by mass.
As said aspect [2], an acrylonitrile * styrene * N-phenylmaleimide copolymer etc. are mentioned.
In addition, acrylonitrile / styrene / methyl methacrylate copolymer can be used.

  The aromatic vinyl (co) polymer (A12) can be produced by polymerizing a vinyl monomer (b2) containing an aromatic vinyl compound in the presence or absence of a polymerization initiator. it can. When a polymerization initiator is used as the polymerization method, solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization and the like are suitable, and these polymerization methods may be used in combination. Moreover, when not using a polymerization initiator, it can be set as thermal polymerization.

As said polymerization initiator, the compound illustrated by description of the manufacturing method of the said copolymer resin (A11) can be used individually by 1 type or in combination of 2 or more types. The usage-amount of the said polymerization initiator is 0.1-1.5 mass% normally with respect to the said vinylic monomer (b2) whole quantity.
In addition, the chain transfer agent, the emulsifier, etc. which were illustrated in description of the manufacturing method of the said copolymer resin (A11) can be used as needed.

  In the production of the aromatic vinyl (co) polymer (A12), the polymerization may be started with the total amount of the vinyl monomer (b2) being accommodated in the reaction system, or arbitrarily selected. The polymerization may be carried out by adding the monomer component separately or continuously. Furthermore, when using the said polymerization initiator, it can add to a reaction system collectively or continuously.

  The said aromatic vinyl type (co) polymer (A12) can be used individually by 1 type or in combination of 2 or more types.

  In the case where the rubber-reinforced aromatic vinyl resin is made of the copolymer resin (A11) and the mixture of the copolymer resin (A11) and the aromatic vinyl (co) polymer (A12) The intrinsic viscosity [η] (measured in methyl ethyl ketone at 30 ° C.) of a component soluble in acetone of this rubber-reinforced aromatic vinyl resin (however, if the rubbery polymer is an acrylic rubber, acetonitrile) ) Is preferably 0.1 to 2.5 dl / g, more preferably 0.2 to 1.5 dl / g, still more preferably 0.2 to 1.2 dl / g. When the intrinsic viscosity [η] is within the above range, the moldability of the first thermoplastic resin composition is excellent, and the thickness accuracy of the first resin layer is also excellent.

Here, the intrinsic viscosity [η] can be obtained in the following manner.
When determining the graft ratio in the rubber-reinforced aromatic vinyl resin (copolymer resin (A11)), the acetone-soluble component recovered after centrifugation (if the rubbery polymer is an acrylic rubber, the acetonitrile-soluble component) ) Is dissolved in methyl ethyl ketone, five different concentrations are prepared, and the reduced viscosity at each concentration is measured at 30 ° C. using an Ubbelohde viscometer to determine the intrinsic viscosity [η].

  The graft ratio and the intrinsic viscosity [η] are a polymerization initiator, a chain transfer agent, an emulsifier, which are used when the copolymer resin (A11) and the aromatic vinyl (co) polymer (A12) are produced. It can be easily controlled by adjusting the type and amount of the solvent and the like, as well as the polymerization time and polymerization temperature.

In the case of imparting sufficient heat resistance to the first resin layer, the rubber-reinforced aromatic vinyl resin preferably includes a structural unit (u) derived from a maleimide compound. The structural unit (u) may be derived from the copolymer resin (A11), or may be derived from the aromatic vinyl (co) polymer (A12). Moreover, you may originate in both.
The content of the structural unit (u) for making the first resin layer excellent in heat resistance is preferably 1 to 30% by mass, more preferably 100% by mass when the rubber-reinforced aromatic vinyl resin is 100% by mass. It is 5-28 mass%. When there is too much content of the said structural unit (u), the flexibility of a 1st resin layer may fall.

  Although the said polyester-type resin will not be specifically limited if it is resin which has an ester bond in the principal chain of a molecule | numerator, Usually, saturated polyester resin is used. This saturated polyester resin may be a homopolymerized polyester or a copolyester.

As the polyester resin, for example, those obtained by polycondensation of a dicarboxylic acid component and a dihydroxy component, polycondensation of an oxycarboxylic acid component or a lactone component, and the like can be used.
Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid (2,6-naphthalenedicarboxylic acid, etc.), diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylmethanedicarboxylic acid, diphenylethanedicarboxylic acid, diphenylketonedicarboxylic acid. Fatty acids having about 8 to 12 carbon atoms such as aromatic dicarboxylic acids having about 8 to 16 carbon atoms such as acids or derivatives thereof, cyclohexanedicarboxylic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, highmic acid, etc. Aliphatic dicarboxylic acids having about 2 to 40 carbon atoms, such as cyclic dicarboxylic acids or derivatives thereof, such as adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, hexadecanedicarboxylic acid, and dimer acid Or derivatives thereof.

The above derivatives include derivatives capable of forming an ester, for example, lower alkyl esters such as dimethyl ester, acid halides such as acid anhydride and acid chloride, and the like.
These dicarboxylic acid components can be used alone or in combination of two or more.

  In addition, as the dihydroxy component, straight chain such as ethylene glycol, trimethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexanediol, octanediol, decanediol, etc. Aliphatic alkylene diols such as branched chain C2-C12 alkylene diols, cyclohexane diol, cyclohexane dimethanol, hydrogenated bisphenol A and other alicyclic diols, hydroquinone, resorcin, dihydroxyphenyl, naphthalenediol, dihydroxydiphenyl ether , Bisphenol A, adducts obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to bisphenol A (diethoxylated bisphenol A, etc. Aromatic diols such as diethylene glycol, triethylene glycol, polyoxyethylene glycol, ditetramethylene glycol, polytetramethylene ether glycol, dipropylene glycol, tripropylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol and other polyoxy Examples include alkylene glycol.

The dihydroxy component may be a substituted product such as an alkyl group, an alkoxy group, or a halogen.
These dihydroxy components can be used alone or in combination of two or more.

Examples of the oxycarboxylic acid component include oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid, and diphenyleneoxycarboxylic acid, and derivatives thereof.
These oxycarboxylic acid components can be used alone or in combination of two or more.

Examples of the lactone component include propiolactone, butyrolactone, valerolactone, and ε-caprolactone.
These lactone acid components can be used singly or in combination of two or more.

When the polyester resin is a copolyester, the copolymerizable monomer used for the formation thereof may be a linear alkylene glycol such as ethylene glycol, propylene glycol, or 1,4-butanediol. Polyoxyalkylene glycols having poly (oxy-alkylene) units such as alkylene glycol and diethylene glycol and having an oxyalkylene unit having a repeat number of about 2 to 4, such as adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc. Examples thereof include aromatic dicarboxylic acids having an asymmetric structure such as aliphatic dicarboxylic acid, phthalic acid, and isophthalic acid.
Furthermore, in addition to the above compounds, polyfunctional monomers such as polyvalent carboxylic acids such as trimellitic acid, trimesic acid and pyromellitic acid, and polyhydric alcohols such as glycerin, trimethylolpropane and pentaerythritol, as necessary. May be used in combination.

  Examples of the polyester resins include polyalkylene terephthalates such as polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT), polyhexamethylene terephthalate, polycyclohexane-1,4-dimethyl terephthalate, and polyneopentyl terephthalate. , Homopolymerized polyester such as polyethylene isophthalate, polyethylene naphthalate, polybutylene naphthalate, polyalkylene naphthalate such as polyhexamethylene naphthalate, copolymerized polyester mainly containing alkylene terephthalate unit and / or alkylene naphthalate unit, liquid crystal Examples include polyester. Of these, polybutylene terephthalate is preferred. Moreover, these can be used individually by 1 type or in combination of 2 or more types.

  The olefin resin is not particularly limited as long as it is a polymer including a structural unit derived from an α-olefin having 2 or more carbon atoms. A preferred olefin resin is a polymer containing a structural unit composed of an α-olefin having 2 to 10 carbon atoms. Therefore, as the olefin resin, a (co) polymer mainly containing one or more structural units composed of α-olefins having 2 to 10 carbon atoms; 1 of structural units composed of α-olefins having 2 to 10 carbon atoms; Examples thereof include a copolymer mainly containing at least one species and at least one structural unit composed of a compound copolymerizable with the α-olefin. These can be used alone or in combination of two or more.

  Examples of the α-olefin include ethylene, propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, 3-methylhexene-1, vinyl acetate, vinyl chloride, vinyl Alcohol etc. are mentioned. These may be used alone or in combination of two or more. Of these, ethylene, propylene, butene-1, 3-methylbutene-1 and 4-methylpentene-1 are preferred.

  Examples of the compound used for forming other structural units constituting the olefin resin include 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 7-methyl-1,6- Non-conjugated dienes such as octadiene and 1,9-decadiene are exemplified. These may be used alone or in combination of two or more.

  Examples of the olefin resin include polyethylene, polypropylene, ethylene / propylene copolymer, polybutene-1, ethylene / butene-1 copolymer, ethylene / vinyl acetate copolymer, ethylene / vinyl chloride copolymer, and ethylene / vinyl. Examples include alcohol copolymers and ionomers.

The olefin resin may be crystalline or amorphous.
The melting point (based on JIS K7121) of the olefin resin is preferably 40 ° C. or higher.
The molecular weight of the olefin-based resin is not particularly limited, but from the viewpoint of moldability, the melt flow rate (based on JIS K7210; hereinafter also referred to as “MFR”) is preferably 0.01 to 500 g / 10. Min, more preferably 0.05 to 100 g / 10 min, and those having a molecular weight corresponding to each value are preferred.

〔式中、Ｒ^１は、ビニル基、アミノ基、アクリロイル基、メタクリロイル基及びエポキシ結合のうちの少なくとも１種を含む有機基であり、Ｒ^２、Ｒ^３及びＲ^４は、互いに同一又は異なって、１又は２以上のハロゲン原子が置換してもよい炭化水素基であり、ｎは０又は１である。〕 Next, the silane coupling agent contained in the raw material composition is not particularly limited, and may be either water-soluble or water-insoluble. In the present invention, an organosilane compound represented by the following general formula (1) is preferable.

[Wherein, R ¹ is an organic group containing at least ^one of a vinyl group, an amino group, an acryloyl group, a methacryloyl group and an epoxy bond, and R ² , R ³ and R ⁴ are the same or different from each other. 1 or 2 or more halogen atoms that may be substituted, and n is 0 or 1. ]

The amino group used as R ¹ in the general formula (1) may be any of a primary amino group, a secondary amino group, a tertiary amino group, and an alkylene polyamino group.
Examples of the organic group containing an epoxy bond include a γ-glycidoxypropyl group.

Moreover, the hydrocarbon group which may be substituted by a halogen atom, used as R ² , R ³ and R ⁴ in the general formula (1) is preferably an organic group having 1 to 10 carbon atoms and linear Either a branched or branched aliphatic hydrocarbon group or an aromatic hydrocarbon group may be used.

  Examples of the organic silane compound represented by the general formula (1) include vinyl silane couplings such as vinyl trimethoxy silane, vinyl triethoxy silane, vinyl triisopropoxy silane, vinyl tris (β-methoxy ethoxy) silane, and allyl trimethoxy silane. Agent: aminosilane coupling such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane Agents such as 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltriethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldiethoxysilane Methylsilane such as 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane Coupling agent: γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ -An epoxy silane coupling agent such as glycidoxypropylmethyldiethoxysilane. These may be used alone or in combination of two or more. Of the above compounds, an acrylic silane coupling agent and a methacryl silane coupling agent are preferred.

  The content of the silane coupling agent contained in the raw material composition is preferably 0.05 to 20 parts by mass, more preferably 0.07 to 15 parts with respect to 100 parts by mass of the first thermoplastic resin. It is a mass part, More preferably, it is 0.1-10 mass part. When the content of the silane coupling agent is within the above range, in the obtained first resin layer, adhesiveness with a filler part including an ethylene / vinyl acetate copolymer composition and the like embedding a solar cell element Excellent. In addition, when there is too much content of the said silane coupling agent, there exists a tendency for the external appearance of the back surface protection film for solar cells of this invention provided with the 1st resin layer to be obtained, and when too little, the said filler part and There is a tendency for the adhesion of the resin to decrease.

  The raw material composition may contain an additive depending on the purpose and application. This additive includes antioxidants, ultraviolet absorbers, anti-aging agents, colorants, fluorescent brighteners, weathering agents, fillers, antistatic agents, flame retardants, antifogging agents, antibacterial agents, antifungal agents, Antifouling agents, tackifiers and the like can be mentioned.

Examples of the antioxidant include hindered amine compounds, hydroquinone compounds, hindered phenol compounds, sulfur-containing compounds, and phosphorus-containing compounds. These can be used alone or in combination of two or more.
The content of the antioxidant is preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the first thermoplastic resin.

Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, and triazine compounds. These can be used alone or in combination of two or more.
The content of the ultraviolet absorber is preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the first thermoplastic resin.

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

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

The first resin layer is a layer obtained by using a first thermoplastic resin composition obtained by melt-kneading a raw material composition containing a first thermoplastic resin and a silane coupling agent.
The melt kneading method of the raw material composition is not particularly limited, and a method in which all components including the first thermoplastic resin and the silane coupling agent are melt kneaded; the first thermoplastic resin and the silane coupling agent are melt kneaded. While adding other raw material components separately or continuously and continuing the melt-kneading; dividing the silane coupling agent while melting and kneading the first thermoplastic resin and other raw material components Alternatively, continuously adding and continuing the melt-kneading; while melt-kneading the first thermoplastic resin, the silane coupling agent and other raw material components are added separately or continuously, and the melt-kneading is continued. And the like.
Examples of the apparatus used for melt kneading include a single screw extruder, a twin screw extruder, a Banbury mixer, a kneader, and a continuous kneader.

  When the back surface protective film for solar cells of the present invention is a single-layer film 1A as shown in FIG. 1, the production method of this film 1A is not particularly limited, and is an extrusion method (inflation film molding method, T-die casting). Film forming method), calender forming method, press forming method and the like.

  Since the back surface protective film for solar cells of this invention is equipped with the 1st resin layer obtained using the said 1st thermoplastic resin composition, it embeds a solar cell element in the surface at the side of the 1st resin layer. Adhesiveness between the first resin layer and a filler part containing an ethylene / vinyl acetate copolymer composition that embeds the solar cell element without providing an adhesive layer for bonding with the filler part. Excellent. Moreover, since this 1st resin layer has the said structure, when the back surface protection film for solar cells of this invention is a laminated | multilayer film, 1st resin layer and other resin which faces this 1st resin layer Excellent adhesion to layers.

  The thickness of the back surface protective film for solar cells of the present invention is preferably 10 to 1,000 μm. The lower limit of the thickness is preferably 15 μm, more preferably 20 μm, and still more preferably 25 μm. The upper limit of the thickness is preferably 950 μm, more preferably 900 μm, and still more preferably 850 μm.

  When the back surface protective film for solar cells of the present invention is a single layer type film (only the first resin layer), the lower limit of the thickness is preferably 10 μm from the viewpoint of adhesiveness with the filler part. The thickness is preferably 15 μm, more preferably 20 μm. The upper limit of the thickness is usually 1,000 μm, preferably 800 μm, more preferably 600 μm, and still more preferably 500 μm.

  As described above, the back surface protective film for a solar cell of the present invention may be a film composed of only the first resin layer, that is, a single-layer film (see FIG. 1), the first resin layer 11, It may be a laminated film composed of another layer 15 bonded to the first resin layer 11 (see FIGS. 2 and 3).

The other layer 15 may be a layer that imparts at least one action of hydrolysis resistance, water resistance (moisture resistance), light reflectivity, and flame retardancy, depending on the purpose and application. The other layer 15 may be a single layer or may be composed of two or more layers.
The constituent material of the other layer 15 may be a resin composition (thermoplastic resin composition or cured resin composition), an inorganic compound, a metal, or the like.
A film 1 </ b> B in FIG. 2 that represents a laminated film includes a first resin layer 11 and another layer 15 bonded to the first resin layer 11. In FIG. 2, the other layer 15 represents another resin layer.
3 is a film in which the other layer 15 includes a metal layer 151 and a resin layer 153, and the first resin layer 11, the metal layer 151, and the resin layer 153 are sequentially joined.

  When the back surface protective film for solar cells of the present invention is a laminated film 1B as shown in FIGS. 2 and 3, the thicknesses of the first resin layer 11 and the other layer 15 are preferably 5 to 600 μm, respectively. And 5 to 800 μm, more preferably 10 to 500 μm and 8 to 700 μm.

The back surface protective film for solar cells of this invention is illustrated below.
(1) When light having a wavelength of 400 to 1,400 nm is radiated to the surface of the first resin layer in the solar cell back surface protective film, a film having a reflectance of 50% or more with respect to the light (hereinafter referred to as “the present invention”). ("Film (I)")
(2) A film having a first resin layer having a transmittance of 60% or more for light having a wavelength of 800 to 1,400 nm and an absorption factor of 60% or more for light having a wavelength of 400 to 700 nm (hereinafter referred to as “this” Invented film (II) ")

In the film (I) of the present invention, the reflectance with respect to light having a wavelength of 400 to 1,400 nm is the above-mentioned light on the surface of the first resin layer of the solar cell back surface protective film (thickness 10 to 1,000 μm) of the present invention. Is measured by radiating. The reflectance is 50% or more, preferably 60% or more, more preferably 70% or more. The higher the reflectance, the more the light can be reflected toward the solar cell element disposed in the filler portion, and the photoelectric conversion efficiency can be improved.
In the present invention, “the reflectance with respect to light having a wavelength of 400 to 1,400 nm is 50% or more” means that the reflectance of light in the wavelength region from 400 nm to 1,400 nm is 400 nm or every 1,400 nm to 20 nm. This means that the average value calculated using each reflectance is 50% or more, and it does not require that all the reflectances of light in the above-mentioned wavelength region are 50% or more.

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

In the film (I) of the present invention, it is preferable that the L value (brightness) of the surface of the first resin layer is 60 or more in order to set the reflectance to light having a wavelength of 400 to 1,400 nm to 50% or more. .
Accordingly, the first thermoplastic resin composition constituting the first resin layer that satisfies the above properties is a white system in a composition obtained by melt-kneading the raw material composition containing the first thermoplastic resin and the silane coupling agent. A thermoplastic resin composition containing a colorant is preferred.

Examples of the white colorant include titanium oxide, zinc oxide, calcium carbonate, barium sulfate, calcium sulfate, alumina, silica, 2PbCO ₃ .Pb (OH) ₂ , [ZnS + BaSO ₄ ], talc, and gypsum. Of these, titanium oxide is preferred. Moreover, these can be used individually or in combination of 2 or more. The content ratio of the white colorant in the first thermoplastic resin composition is preferably 1 to 45 parts by mass, more preferably 100 parts by mass with respect to 100 parts by mass of the first thermoplastic resin, from the viewpoint of reflectivity to the light. Is 3 to 40 parts by mass, more preferably 5 to 30 parts by mass. When there is too much content of this white type coloring agent, the flexibility of the film (I) of this invention may fall.
In addition, if it does not reduce the reflectance with respect to the said light to the surface of the 1st resin layer of the film (I) of this invention to less than 50%, according to the objective, a use, etc., further another colorant is added. Can be used. When other colorants are used, the content is usually 5 parts by mass or less with respect to 100 parts by mass of the first thermoplastic resin.

In the present invention, as shown in FIG. 2, a laminated film 1 </ b> B including a first resin layer 11 and another layer 15, and the light of only the film constituting the first resin layer 11. When the reflectance is less than 50% ( when the first resin layer does not contain a white colorant or the like) , the wavelength of 400 to 400 on the surface of the first resin layer is selected by selecting the constituent material of the other layer 15. It can be set as the film (I) of this invention whose reflectance with respect to 1,400 nm light is 50% or more, and, thereby, a photoelectric conversion efficiency can be improved.

  In any case where the film (I) of the present invention is a single-layer film or a laminated film, the light reflecting in photoelectric conversion is excellent, so that sunlight is adjacent. When it leaks from the gap of the solar cell element toward the back surface protective film for solar cell, the sunlight is reflected from the first resin layer, and the reflected light is supplied to the back surface of the solar cell element and used for photoelectric conversion. Thus, the power generation efficiency can be improved.

On the other hand, in the film (II) of the present invention, the transmittance for light having a wavelength of 800 to 1,400 nm and the absorbance for light having a wavelength of 400 to 700 nm are on the surface of the first resin layer, that is, a thickness of 10 to 10 nm. Each light is emitted only to the surface of a 1,000 μm monolayer film (only the first resin layer) or to the film (thickness 5 to 1,000 μm) constituting the first resin layer in the laminated film. It is to be measured.
The transmittance is 60% or more, preferably 65% or more, and more preferably 70% or more. As the transmittance is higher, heat storage due to light having a wavelength of 800 to 1,400 nm is suppressed in the first resin layer, so that heat storage of the filler portion bonded to the first resin layer is also suppressed. And the thermal storage of the solar cell module formed using this film (II) is suppressed, and electric power generation efficiency can be improved.
In the present invention, “the transmittance with respect to light having a wavelength of 800 to 1,400 nm is 60% or more” means that the transmittance of light in the wavelength region from 800 nm to 1,400 nm using the film constituting the first resin layer. Is measured every 800 nm or from 1,400 nm to 20 nm, and the average value calculated using each transmittance is 60% or more, and the light transmittance in the above wavelength range is all 60% or more. It is not required to be.

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

In the film (II) of the present invention, in the film constituting the first resin layer, the transmittance for light having a wavelength of 800 to 1,400 nm is 60% or more, and the absorptance for light having a wavelength of 400 to 700 nm is 60% or more. Therefore, the film constituting the first resin layer preferably has a property of absorbing visible light and transmitting infrared light.
Therefore, the first thermoplastic resin composition constituting the first resin layer that satisfies the above properties is a first thermoplastic resin, a silane coupling agent, and a colored material that absorbs visible light and transmits infrared light. A composition obtained by melt-kneading a raw material composition containing an agent (hereinafter referred to as “infrared transmitting colorant”) is preferable.

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

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

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

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

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

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

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

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

The content ratio of the infrared transmissive colorant in the first thermoplastic resin composition is preferably 5 parts by mass with respect to 100 parts by mass of the first thermoplastic resin from the viewpoints of the transmittance and absorption with respect to each light. Hereinafter, it is more preferably 0.1 to 5 parts by mass.
In addition, the 1st thermoplastic resin composition which comprises the 1st resin layer contained in the film (II) of this invention is according to the objective, a use, etc., unless the said permeability and absorptivity are reduced. Other colorants can be included. For example, a solar cell module having various appearances can be obtained by using a yellow pigment, a blue pigment, or the like as a colorant other than the infrared-transmitting colorant and using the following combinations.
[1] Brown coloration by combination of black-based infrared transmitting colorant and yellow pigment [2] Dark blue coloration by combination of black-based infrared transmitting colorant and blue pigment When other colorant is used, The content in the thermoplastic resin composition is usually 200 parts by mass or less, preferably 0.01 to 100 parts by mass with respect to 100 parts by mass of the infrared transmitting colorant.

  Carbon black is known as a dark colorant. Since this carbon black absorbs light having a wavelength in the infrared region, the temperature of the film rises when sunlight leaks from the gap between adjacent solar cell elements toward the film (II) of the present invention. It is easy to increase the temperature of the filler part including the solar cell element, and may reduce the power generation efficiency, but by using the infrared transmissive colorant, the design property is not reduced without reducing the power generation efficiency. And excellent durability.

When the film (II) of the present invention is a single-layer film, that is, a film 1A made of a first resin layer (see FIG. 1), sunlight is reflected from the gap between adjacent solar cell elements, and the back surface for solar cells. When leaking toward the protective film, the first resin layer transmits light having a wavelength of 800 to 1,400 nm, and heat storage due to this light is suppressed, so that the filler portion that adheres to the first resin layer Heat storage is suppressed. And the heat storage in the solar cell module formed using this film (II) is also suppressed, and the fall of power generation efficiency can be suppressed. Therefore, when this film (II) is separately combined with a member having light reflectivity to form a solar cell module, a part of sunlight leaked from the gap between adjacent solar cell elements and transmitted through the first resin layer. Can be reflected from the member, and the reflected light can be supplied to the back surface of the solar cell element while being transmitted through the first resin layer, and used for photoelectric conversion to improve power generation efficiency.
In addition, when the film (II) of the present invention is a laminated film as shown in FIG. 2, that is, a film 1 </ b> B including the first resin layer 11 and another layer 15, For example, by providing light reflectivity, part of sunlight leaking from the gap between adjacent solar cell elements and transmitted through the first resin layer is reflected from the member, and the reflected light is reflected from the first resin layer. While being transmitted, it can be supplied to the back surface of the solar cell element and used for photoelectric conversion to improve power generation efficiency.

When the film (II) of the present invention is a laminated film, the first resin layer has a transmittance of 60% or more for light having a wavelength of 800 to 1,400 nm and an absorptance for light of 400 to 700 nm. %, And when light having a wavelength of 800 to 1,400 nm is radiated to the surface of the first resin layer in the solar cell back surface protective film, the reflectance for this light is preferably 50% or more. . By providing this configuration, it has a dark color appearance and is excellent in appearance, and when sunlight hits the film, deformation of components such as the film can be suppressed and power generation efficiency can be improved.
In order to obtain such a film (II), the other layer is preferably a resin layer, and this resin layer is preferably a white resin layer. And it is preferable that the composition which comprises this white resin layer contains a white colorant. When this composition is a thermoplastic resin composition and this thermoplastic resin composition contains a white colorant, the type of the white colorant and its content relative to the thermoplastic resin are the first heat The explanation in the plastic resin composition applies.

  When the back surface protective film for solar cells of the present invention is a laminated film including the first resin layer and other layers, from the viewpoint of optical properties such as productivity, flexibility, workability, and reflectivity. The other layer is a resin layer made of a thermoplastic resin composition (hereinafter referred to as “second thermoplastic resin composition”) containing a thermoplastic resin (hereinafter referred to as “second thermoplastic resin”). It is preferable to include.

  The second thermoplastic resin is not particularly limited as long as it is a resin having thermoplasticity, and the thermoplastic resins exemplified in the description of the first thermoplastic resin can be used, one kind alone or two kinds. A combination of the above can be used. In the present invention, rubber reinforced aromatic vinyl resins, polyester resins and olefin resins are preferable, and rubber reinforced aromatic vinyl resins are particularly preferable. When the second thermoplastic resin contains a rubber-reinforced aromatic vinyl resin, it is excellent in hydrolysis resistance, dimensional stability, impact resistance, and the like.

  The second thermoplastic resin composition may be a composition composed only of the second thermoplastic resin, may be a composition containing the second thermoplastic resin and an additive, or may be a second heat. A composition containing a plastic resin, a silane coupling agent, and an additive may be used. The content ratio of the additive and the silane coupling agent can be the same as in the case of the first thermoplastic resin composition.

When the back surface protective film for solar cells of the present invention is a laminated film 1B as shown in FIG. 2, the manufacturing method of this film 1B is selected according to the constituent material of the other layer 15 and is not particularly limited. When the material is a thermoplastic resin composition, methods such as a co-extrusion method (T-die cast film molding method, etc.), a thermal fusion method, a dry lamination method, and the like can be given. A cured resin composition, an inorganic compound, a metal And the like, examples thereof include a heat fusion method, a vapor deposition method, and a sputtering method. In addition, a film obtained using the first thermoplastic resin composition and a film or the like that constitutes the other layer 15 may be a polyurethane resin composition, an epoxy resin composition, an acrylic resin composition, or the like. You may join by the adhesive agent of this.
Examples of the film constituting the other layer 15 include a film made of a thermoplastic resin composition containing a polyester resin (hereinafter referred to as “polyester film”), a film for forming a water vapor barrier layer described later, and the like. . Examples of the polyester film include a polyethylene terephthalate film, a polyethylene naphthalate film, and a polybutylene terephthalate film. The other layer 15 can be formed using a commercially available product. For example, “Melinex 238” (trade name) manufactured by Teijin DuPont, “SR55” (trade name) manufactured by SKC, “Toray” Lumirror X10P, Lumirror ZV10, Lumirror X10S, Lumirror E20 (above, trade name), etc. are listed. When these products are used, the surface of the other layer 15 is given scratch resistance. Can be.

When the back surface protective film for solar cells of the present invention is a laminated film, the other layer 15 can include a water vapor barrier layer. The other layer 15 can consist of only a water vapor | steam barrier layer, and also can consist of a water vapor | steam barrier layer and another resin layer.
The solar cell back surface protective film 1 </ b> C including the water vapor barrier layer is exemplified in FIG. 3, and includes a first resin layer 11, a water vapor barrier layer 15 including a metal layer 151 and a resin layer 153, and a first resin layer. 11 and the metal layer 151 are joined.

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

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

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

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

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

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

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

A method for producing a laminated film in which the other layer is a water vapor barrier layer is exemplified below.
(1) After producing a single layer type film as described above using the first thermoplastic resin composition, the surface of this single layer type film and the film for forming a water vapor barrier layer are thermally fused or Method of joining by dry lamination or adhesive (2) After producing a single layer type film as described above using the first thermoplastic resin composition, a metal and / or on the surface of the single layer type film Method for Forming Film Consisting of Metal Oxide (3) After producing a single layer type film as described above using the first thermoplastic resin composition, a metal and / Alternatively, a method of forming a film made of a metal oxide, and then bonding this film to another film using the thermoplastic resin composition by thermal fusion, dry lamination, or an adhesive.

The solar cell module of the present invention is provided with the solar cell back surface protective film of the present invention. A schematic diagram of the solar cell module of the present invention is shown in FIG.
The solar cell module 2 in FIG. 4 includes a surface-side transparent protective member 21, a surface-side sealing film (surface-side filler) 23, a solar cell element 25, and a back surface side from the sunlight receiving surface side (upper side in the drawing). The sealing film (back surface side filler material portion) 27 and the solar cell back surface protective film 1 of the present invention may be disposed in this order.

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

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

  Although not shown in FIG. 4, the solar cell element 25 normally includes a wiring electrode and an extraction electrode. The wiring electrode has an action of collecting electrons generated in the plurality of solar cell elements by receiving sunlight, for example, a solar cell element on the surface side sealing film (surface side filler part) 21 side, It connects so that the solar cell element by the side of the back surface side sealing film (back surface side filler material part) 27 side may be connected. The take-out electrode has an action of taking out electrons collected by the wiring electrode or the like as a current.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

<Exposure test>
The back protective film for solar cells was cut into a strip shape (length 200 mm, width 15 mm, thickness described in Table 1), and allowed to stand for 2,000 hours under conditions of temperature 85 ° C. and humidity 85% RH.

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

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

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

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

1-13. Scratch resistance The surface of the back surface protective film for solar cells, which is not the first resin layer, is subjected to 500 reciprocal frictions using a reciprocating friction tester manufactured by Tohken Seimitsu Kogyo Co., Ltd. with cotton canvas No. 3 and a vertical load of 500 g. It was. The subsequent surface was visually observed and judged according to the following criteria.
○: No scratch was observed Δ: Scratch was slightly observed ×: Scratch was clearly observed

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

2-1. Acrylic rubber reinforced aromatic vinyl resin Resin reactor, acrylic rubbery polymer obtained by emulsion polymerization of 99 parts of n-butyl acrylate and 1 part of allyl methacrylate (volume average particle diameter: 100 nm, 50 parts of latex having a solid content concentration of 40% (in terms of solid content) containing 90%) was added, and further diluted with 1 part of sodium dodecylbenzenesulfonate and 150 parts of ion-exchanged water. Thereafter, the inside of the reactor was replaced with nitrogen gas, and 0.02 part of disodium ethylenediaminetetraacetate, 0.005 part of ferrous sulfate and 0.3 part of sodium formaldehydesulfoxylate were added, and the mixture was stirred up to 60 ° C. The temperature rose.
On the other hand, 50 parts of a mixture of 37.5 parts of styrene and 12.5 parts of acrylonitrile, 1.0 part of terpinolene and 0.2 part of cumene hydroperoxide are placed in a container, and the inside of the container is replaced with nitrogen gas. A mass composition was obtained.
Next, the monomer composition was added to the reactor at a constant flow rate over 5 hours, and polymerization was performed at 70 ° C. to obtain a latex. Magnesium sulfate was added to this latex to coagulate the resin component. Then, acrylic rubber reinforced aromatic vinyl resin was obtained by washing with water and drying. The graft ratio is 93%, and the intrinsic viscosity [η] (in methyl ethyl ketone, 30 ° C.) is 0.30 dl / g. The glass transition temperature (Tg) is 101 ° C.

2-2. Butadiene rubber reinforced aromatic vinyl resin In a glass reaction vessel equipped with a stirrer, 75 parts of ion exchange water, 0.5 part of potassium rosinate, 0.1 part of tert-dodecyl mercaptan, polybutadiene latex (volume average particle diameter: 270 nm, gel content: 90%) 32 parts (solid content conversion), styrene / butadiene copolymer latex (styrene unit content: 25%, volume average particle size: 550 nm, gel content: 50%) 8 parts (solid content) Conversion), 15 parts of styrene and 5 parts of acrylonitrile were added, and the temperature was increased while stirring in a nitrogen stream. When the internal temperature reached 45 ° C., an aqueous solution in which 0.2 parts of sodium pyrophosphate, 0.01 parts of ferrous sulfate heptahydrate and 0.2 parts of glucose were dissolved in 20 parts of ion-exchanged water was added. . Thereafter, 0.07 part of cumene hydroperoxide was added, polymerization was started at 70 ° C., and polymerization was performed for 1 hour.
Thereafter, 50 parts of ion exchange water, 0.7 part of potassium rosinate, 30 parts of styrene, 10 parts of acrylonitrile, 0.05 part of tert-dodecyl mercaptan and 0.01 part of cumene hydroperoxide are continuously added over 3 hours. The polymerization was continued. After polymerizing for 1 hour, 0.2 part of 2,2′-methylene-bis (4-ethylene-6-tert-butylphenol) was added to complete the polymerization to obtain a latex.
Next, magnesium sulfate was added to the latex to coagulate the resin component. Thereafter, butadiene rubber reinforced aromatic vinyl resin was obtained by washing with water and drying. The graft ratio is 72%, and the intrinsic viscosity [η] of the acetone-soluble component is 0.47 dl / g. The glass transition temperature (Tg) is 105 ° C.

2-3. Acrylonitrile / styrene copolymer AS resin “SAN-H” (trade name) manufactured by Technopolymer Co., Ltd. was used. The glass transition temperature (Tg) is 108 ° C.

2-4. Acrylonitrile / styrene / N-phenylmaleimide copolymer Acrylonitrile / styrene / N-phenylmaleimide copolymer “Polyimilex PAS1460” (trade name) manufactured by Nippon Shokubai Co., Ltd. was used. The amount of N-phenylmaleimide units is 40%, the amount of styrene units is 51%, and the Mw in terms of polystyrene by GPC is 120,000. The glass transition temperature (Tg) is 173 ° C.

2-5. Polyethylene terephthalate Polyethylene terephthalate “Novapex GM700Z” (trade name) manufactured by Mitsubishi Chemical Corporation was used. The glass transition temperature (Tg) is 75 ° C.
2-6. Polypropylene Polypropylene “EA9” (trade name) manufactured by Nippon Polypro Co., Ltd. was used.

2-7. Silane coupling agent The following 3 types were used.
(X) 3-methacryloxypropyltrimethoxysilane (y) 3-glycidoxypropyltrimethoxysilane (z) vinylmethoxysilane

2-8. White colorant Titanium oxide “Taipeku CR-50-2” (trade name) manufactured by Ishihara Sangyo Co., Ltd. was used. The average primary particle size is 0.25 μm.

2-9. Infrared transmitting colorant A perylene-based black pigment “Lumogen BLACK FK4280” (trade name) manufactured by BASF was used.

2-10. Yellow colorant A quinophthalone yellow pigment “Pariotol Yellow K0961HD” (trade name) manufactured by BASF was used.

  As films for forming other layers, the following water vapor barrier layer forming film and polyester film were used.

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

2-13. Resin layer forming film (F-1)
A white PET film “Lumirror E20” (trade name) manufactured by Toray Industries, Inc. was used. The thickness is 50 μm.
2-14. Resin layer forming film (F-2)
A translucent PET film “Lumirror X10S” (trade name) manufactured by Toray Industries, Inc. was used. The thickness is 50 μm.
2-15. Resin layer forming film (F-3)
A milk white PET film “Melinex 238” (trade name) manufactured by Teijin DuPont was used. The thickness is 75 μm.

3. 3. Production and evaluation of back surface protective film for solar cell 3-1. Manufacture and evaluation of back surface protective film for single-layer solar cell Example 1-1
30 parts of acrylic rubber-reinforced aromatic vinyl resin, 30 parts of acrylonitrile / styrene copolymer, 40 parts of acrylonitrile / styrene / N-phenylmaleimide copolymer, 0.3 part of silane coupling agent (x) A first raw material composition comprising 20 parts of a white colorant was kneaded at 250 ° C. using a Brabender to obtain a first thermoplastic resin composition. Then, the back surface protective film for single layer type solar cells which consists of this 1st thermoplastic resin composition was obtained using T die (thickness 400 micrometers). Various evaluation was performed about this back surface protective film for solar cells. The results are shown in Table 1.

Examples 1-2 to 1-9 and Comparative Examples 1-1 to 1-5
Except having used the component of Table 1 in the predetermined ratio, it carried out similarly to Example 1-1, and obtained the back surface protective film for single layer type solar cells. The kneading temperature and film thickness are shown in Table 1. Various evaluation was performed about this back surface protective film for solar cells. The results are also shown in Table 1.

As is apparent from Table 1, for solar cells according to Comparative Examples 1-1 to 1-5 using the first thermoplastic resin composition obtained by kneading the first raw material composition not containing the silane coupling agent. The back surface protective film had a low peel strength of 10 to 15 N in adhesion to a film made of an ethylene / vinyl acetate copolymer, and the adhesiveness was not sufficient.
On the other hand, the back surface protective films for solar cells according to Examples 1-1 to 1-9 using the first thermoplastic resin composition obtained by kneading the first raw material composition containing the silane coupling agent were peeled off. The strength was as high as 65 to 82 N, and the adhesiveness was excellent.

3-2.2 Production and Evaluation of Back Surface Protective Film for Layer Type Solar Cell Example 2-1
The first raw material composition and the second raw material composition for forming the first resin layer and the second resin layer shown in Table 2 were each prepared with a Henschel mixer. Thereafter, using a twin screw extruder (model name “TEX44”, manufactured by Nippon Steel Works), melt kneading is performed at a barrel temperature of 270 ° C., and two types of first thermoplastic resin composition and second thermoplastic resin composition are used. Pellets were obtained.
Next, the first thermoplastic resin composition is used in each extruder using a multilayer film molding machine having a T die having a die width of 1,400 mm and a lip interval of 1.5 mm and two extruders having a screw diameter of 65 mm. And a second thermoplastic resin composition was supplied. Then, the molten resin was discharged from the T die at a melting temperature of 270 ° C. to obtain a two-layer soft film. Thereafter, this two-layer soft film was cooled and solidified with an air knife while being in close contact with a cast roll whose surface temperature was controlled to 95 ° C., and a back surface protective film for a laminated solar cell having a thickness of 400 μm (white- White type) was obtained. The thicknesses of the first resin layer and the second resin layer are as shown in Table 2. Thickness gauge (model name “ID-C1112C”, manufactured by Mitutoyo Co., Ltd.) was used to cut the film after 1 hour from the start of film production. Then, the thickness was measured at intervals of 10 mm (n = 107), and the average value was obtained. Measurement point values in the range of 20 mm from the edge of the film were removed from the average calculation.
Various evaluations were performed on the solar cell back surface protective film, and the results are also shown in Table 2.

Examples 2-2 to 2-8 and comparative examples 2-1 to 2-5
Using the raw materials of the composition for forming the first resin layer and the second resin layer shown in Table 2 and Table 3, in the same manner as in Example 2-1, a back surface protective film for laminated solar cells (white -White type) was obtained. And about these back surface protection films for solar cells, various evaluation was performed and the result was written together in Table 2 and Table 3. FIG.

  From Tables 2 and 3, the following is clear. Examples 2-2, 2-3, 2-7 and 2-8 using the first thermoplastic resin composition containing no silane coupling agent are the first thermoplastic resin compositions containing no silane coupling agent. Compared with Comparative Examples 2-1, 2-2, 2-4, and 2-5 using No. 1, the peel strength was high and the peel state was also good. Moreover, Examples 2-5 and 2-6 using the first thermoplastic resin composition not containing the silane coupling agent are Comparative Examples 2 using the first thermoplastic resin composition not containing the silane coupling agent. Compared with -3, the peel strength was high and the peeled state was also good.

Examples 2-9 to 2-16 and Comparative Examples 2-6 to 2-10
Using the raw materials of the composition for forming the first resin layer and the second resin layer shown in Table 4 and Table 5, in the same manner as in Example 2-1, a back surface protective film for laminated solar cells (black) -White type) was obtained. And about these back surface protection films for solar cells, various evaluation was performed and the result was written together in Table 4 and Table 5. FIG.

Example 2-17
The first raw material composition for forming the first resin layer shown in Table 5 was kneaded at 250 ° C. using a Brabender to obtain a first thermoplastic resin composition. Then, the soft film which consists of this 1st thermoplastic resin composition was obtained using the T die (thickness 170 micrometers).
Next, the resin layer forming film (F-1) was adhered to the surface of the soft film using a polyurethane-based adhesive to obtain a laminated solar cell back surface protective film. And about this back surface protective film for solar cells, various evaluation was performed and the result was written together in Table 5.

  From Tables 4 and 5, the following is clear. Examples 2-10, 2-12, 2-15 and 2-16 using the first thermoplastic resin composition containing the silane coupling agent are the first thermoplastic resin compositions not containing the silane coupling agent. Compared with Comparative Examples 2-6, 2-7, 2-9, and 2-10 using No. 2, the peel strength was high and the peel state was also good. In Examples 2-13, 2-14 and 2-17 using the first thermoplastic resin composition containing the silane coupling agent, the first thermoplastic resin composition containing no silane coupling agent was used. Compared with Comparative Example 2-8, the peel strength was high and the peeled state was also good.

3-3. Production and Evaluation of Back Protective Film for Solar Cell Having Water Vapor Barrier Layer, etc. Example 3-1
The first raw material composition for forming the first resin layer shown in Table 6 was kneaded at 250 ° C. using a Brabender to obtain a first thermoplastic resin composition. Then, the soft film which consists of this 1st thermoplastic resin composition was obtained using the T die (thickness 120 micrometers).
Next, the water vapor barrier layer forming film (R-1) described in Table 6 is adhered to the surface of the soft film using a polyurethane-based adhesive so that the vapor deposition film becomes the outer surface, A solar cell back surface protective film having a water vapor barrier layer was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 6.

Examples 3-2 to 3-4 and 3-7 to 3-10
After using the 1st raw material composition for forming the 1st resin layer shown in Table 6 and Table 7 and obtaining a flexible film like Example 3-1, it describes in Table 6 and Table 7. The water vapor barrier layer forming film or the (second) resin layer forming film is adhered using a polyurethane-based adhesive so that the deposited film becomes the outer surface, and the water vapor barrier layer or the second resin layer is attached. The solar cell back surface protective film was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 6 and Table 7. FIG.

Example 3-5
The first raw material composition for forming the first resin layer shown in Table 6 was kneaded at 250 ° C. using a Brabender to obtain a first thermoplastic resin composition. Then, the soft film which consists of this 1st thermoplastic resin composition was obtained using the T die (thickness 170 micrometers).
Next, the film for water vapor barrier layer formation (R-1) described in Table 6 was adhered to the surface of the soft film using a polyurethane-based adhesive so that the vapor deposition film became the outer surface. . Furthermore, the resin layer forming film (F-2) described in Table 6 is adhered to the surface of the vapor deposition film in the water vapor barrier layer using a polyurethane-based adhesive, and the sun having the water vapor barrier layer and the second resin layer. A battery back surface protective film was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 6.

Examples 3-6, 3-11 to 13-13
Using the materials shown in Table 6 and Table 7, a back surface protective film for a solar cell having a water vapor barrier layer and a second resin layer was obtained in the same manner as in Example 3-5. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 6 and Table 7. FIG.

  The back surface protective film for solar cells of the present invention includes a filler containing an ethylene / vinyl acetate copolymer composition or the like that embeds a solar cell element constituting a solar cell module in the resin layer (first resin layer). It is excellent in adhesiveness to parts, heat resistance and weather resistance, and as a whole film, it is excellent in light reflectivity or design, and of course a solar cell module constituting a solar cell used for a roof of a house This is useful as a member for protecting the back surface of a flexible solar cell module.

1, 1A, 1B and 1C: Back surface protective film for solar cell 11: First resin layer 15: Other layers (other resin layers, water vapor barrier layers, etc.)
151: Metal layer 153: Resin layer 2: Solar cell module 21: Front side transparent protective member 23: Front side sealing film 25: Solar cell element 27: Back side sealing film

Claims (10)

  A back protective film for a solar cell, comprising a resin layer obtained by using a thermoplastic resin composition obtained by melt-kneading a raw material composition containing a thermoplastic resin and a silane coupling agent.   The back surface protection for solar cells according to claim 1, wherein when light having a wavelength of 400 to 1,400 nm is radiated to the surface of the resin layer in the back surface protection film for solar cells, the reflectance to the light is 50% or more. the film.   The back surface protective film for solar cells according to claim 1 or 2, wherein the thermoplastic resin composition further contains a white colorant.   2. The back surface for solar cell according to claim 1, wherein the resin layer has a transmittance of 60% or more for light having a wavelength of 800 to 1,400 nm and an absorptance of 60% or more for light having a wavelength of 400 to 700 nm. Protective film.   The back protective film for solar cells according to claim 1 or 4, wherein the thermoplastic resin composition further contains an infrared transmitting colorant.   The back surface protective film for solar cells according to any one of claims 1 to 5, wherein the thermoplastic resin contains a rubber-reinforced aromatic vinyl resin.   Furthermore, the back surface protective film for solar cells in any one of Claims 1 thru | or 6 provided with the other resin layer joined to the said resin layer.   The said back surface protective film for solar cells of Claim 7 whose said other resin layer is a white resin layer.   The back surface protective film for solar cells according to any one of claims 1 to 8, which has a thickness of 10 to 1,000 µm.   A solar cell module comprising the solar cell back surface protective film according to claim 1.

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