JP2010109349A - Solar cell backside protective film, and solar cell module with the same - Google Patents

Abstract

A back surface protective film for solar cells excellent in adhesiveness, heat resistance, flexibility, and weather resistance with a filler part containing an ethylene / vinyl acetate copolymer composition and the like embedding a solar cell element A solar cell module including the same is provided.
A back protective film for solar cell according to the present invention includes a first resin layer, a second resin layer, and a third resin layer in order, and the first resin layer includes a thermoplastic resin. And a layer obtained by using a thermoplastic resin composition obtained by melt-kneading a raw material composition containing a silane coupling agent.
[Selection] Figure 1

Description

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

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

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

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

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

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

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

The present invention is shown below.
1. In the back protective film for a solar cell that includes a first resin layer, a second resin layer, and a third resin layer in order, the first resin layer is also referred to as a thermoplastic resin (hereinafter referred to as “thermoplastic resin (I)”). .) And a thermoplastic resin composition obtained by melt-kneading a raw material composition containing a silane coupling agent (hereinafter also referred to as “first thermoplastic resin composition”). A back surface protective film for solar cells.
2. The back surface for solar cells according to 1 above, wherein when light having a wavelength of 400 to 1,400 nm is radiated to the surface of the first resin layer in the back surface protective film for solar cells, the reflectance with respect to the light is 50% or more. Protective film.
3. 3. The solar cell back surface protective film according to 1 or 2, wherein at least one of the first resin layer, the second resin layer, and the third resin layer includes a white colorant.
4). In the first resin layer, the transmittance for light with a wavelength of 800 to 1,400 nm is 60% or more, the absorptance for light with a wavelength of 400 to 700 nm is 60% or more, and the wavelength is 800 to 1,400 nm. 2. The back surface protective film for solar cells according to 1 above, wherein when light is emitted to the surface of the first resin layer in the back surface protective film for solar cells, the reflectance with respect to the light is 50% or more.
5). The back protective film for a solar cell according to 1 or 4, wherein the first resin layer includes an infrared transmitting colorant, and the second resin layer and / or the third resin layer includes a white colorant.
6). 1 to 5 above, wherein the thermoplastic resin constituting the first resin layer, the thermoplastic resin constituting the second resin layer, and the thermoplastic resin constituting the third resin layer contain an aromatic vinyl resin. The back surface protective film for solar cells in any one of.
7). Furthermore, the back surface protective film for solar cells in any one of said 1 thru | or 6 provided with a water vapor | steam barrier layer and / or a back surface protective layer in the said 3rd resin layer side.
8). 8. The solar cell back surface protective film according to 7 above, comprising a third resin layer, a water vapor barrier layer, and a back surface protective layer sequentially.
9. The back surface protective film for solar cells according to any one of 1 to 8 above, wherein the thickness is 30 to 1,000 μm.
10. A solar cell module comprising the solar cell back surface protective film according to any one of 1 to 9 above.

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

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

  When the thermoplastic resin constituting the first resin layer, the thermoplastic resin constituting the second resin layer, and the thermoplastic resin constituting the third resin layer include an aromatic vinyl resin, It is excellent in hydrolysis resistance, dimensional stability, impact resistance, etc. of the back surface 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 protective film for solar cells of this invention. It is a schematic sectional drawing which shows the other example of the back surface protective film for solar cells of this invention. It is a schematic sectional drawing which shows an example of the solar cell module of this invention.

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

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

The first resin layer is obtained by melt-kneading a raw material composition (hereinafter referred to as “first raw material composition”) containing a thermoplastic resin (hereinafter referred to as “thermoplastic resin (I)”) and a silane coupling agent. It is the layer obtained using the thermoplastic resin composition (henceforth "the 1st thermoplastic resin composition") formed. And this 1st resin layer is excellent in adhesiveness with the filler part which embeds a solar cell element, and has the effect | action which mainly gives flexibility with respect to the back surface protective film for solar cells of this invention. Is a layer.
The said 2nd resin layer is a base layer in the back surface protection film for solar cells of this invention, is a layer which has an effect | action which mainly gives heat resistance with respect to the back surface protection film for solar cells of this invention, and contains a resin component. The material composition is not particularly limited as long as it is a material, but preferably a raw material composition (hereinafter referred to as “second raw material composition”) containing a thermoplastic resin (hereinafter referred to as “thermoplastic resin (II)”) is melt-kneaded. It is a layer obtained by using a thermoplastic resin composition (hereinafter referred to as “second thermoplastic resin composition”).
The said 3rd resin layer is a layer which has an effect | action which mainly gives flexibility with respect to the back surface protection film for solar cells of this invention, and will not be specifically limited if a resin component is included. The third resin layer is preferably melt-kneaded with a raw material composition (hereinafter referred to as “third raw material composition”) containing a thermoplastic resin (hereinafter referred to as “thermoplastic resin (III)”). It is a layer obtained using the thermoplastic resin composition (henceforth "the 3rd thermoplastic resin composition").
The back surface protective film for solar cells of the present invention is preferably a film having heat resistance and flexibility, and at least the first thermoplastic resin composition and the third thermoplastic resin composition are preferably film-forming. A composition having In the present invention, the first, second and third thermoplastic resin compositions are particularly preferably compositions having film-forming properties.
In order to impart heat resistance and flexibility to the solar cell back surface protective film of the present invention, the glass transition temperature (hereinafter referred to as “Tg”) of the thermoplastic resin (I) and the thermoplastic resin (hereinafter referred to as “Tg”). The Tg of III) is preferably the same as or lower than the Tg of the thermoplastic resin (II). In order to impart sufficient flexibility, the Tg of the thermoplastic resin (I) and the Tg of the thermoplastic resin (III) are preferably lower than the Tg of the thermoplastic resin (II). The difference between the Tg of the thermoplastic resin (I) and the Tg of the thermoplastic resin (II) is preferably 10 ° C. or higher, more preferably 15 ° C. or higher, and the Tg of the thermoplastic resin (II) and the thermoplastic resin (III ) Is preferably 10 ° C. or higher, more preferably 15 ° C. or higher.
When two or more kinds of thermoplastic resins are contained in one resin layer and a plurality of Tg are detected in a chart obtained by a differential scanning calorimeter (DSC), the highest temperature among the plurality of Tg is adopted as Tg. Shall.

  In the thermoplastic resin (I) contained in the first raw material composition, the Tg is preferably 90 ° C. to 200 ° C. from the viewpoint of imparting flexibility and heat resistance to the back protective film for solar cells of the present invention. More preferably, the temperature is 95 ° C to 160 ° C, more preferably 95 ° C to 150 ° C, and particularly preferably 110 ° C to 140 ° C.

The thermoplastic resin (I) is not particularly limited as long as it is a thermoplastic resin. For example, aromatic vinyl resins (for example, rubber-reinforced aromatic vinyl resins, acrylonitrile / styrene resins, other aromatic vinyls) (Co) polymers of compounds), polyolefin resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyvinyl acetate resins, saturated polyester resins, polycarbonate resins, acrylic resins (for example, (meth)) (Co) polymers of acrylic ester compounds), fluororesins, ethylene / vinyl acetate resins and the like. These can be used alone or in combination of two or more.
As the thermoplastic resin (I), aromatic vinyl resins, saturated polyester resins and olefin resins are preferable, and aromatic vinyl resins are particularly preferable. When the thermoplastic resin (I) contains an aromatic vinyl resin, the first resin layer having excellent hydrolysis resistance can be formed by the first thermoplastic resin composition.

The aromatic vinyl resin (hereinafter also referred to as “component (I-1)”) is typically a vinyl monomer containing an aromatic vinyl compound in the presence of the rubbery polymer (a1). Rubber-reinforced aromatic vinyl resin (I-1-1) obtained by polymerizing body (b11), (co) polymer of vinyl monomer (b12) containing an aromatic vinyl compound (I-1-2) ), And a mixture of rubber-reinforced aromatic vinyl resin (I-1-1) and (co) polymer (I-1-2).
The rubber-reinforced aromatic vinyl resin (I-1-1) is usually a copolymer resin in which a vinyl monomer (b11) containing an aromatic vinyl compound is graft copolymerized with the rubber polymer (a1). And an ungrafted component that is not grafted on the rubber polymer (a1), that is, a (co) polymer of the remaining vinyl monomer (b11).

  The aromatic vinyl resin (I-1) preferably contains at least one rubber-reinforced aromatic vinyl resin (I-1-1) from the viewpoint of impact resistance and flexibility. One or more of the aromatic vinyl resins (I-1-1) or one or more of the rubber-reinforced aromatic vinyl resins (I-1-1) and the (co) polymer (I-1-2) A combination of one or more of these is particularly preferred. In these cases, the content of the rubber-like polymer (a1) in the aromatic vinyl resin (I-1) is preferably 5 to 40% by mass with respect to 100% by mass of the component (I-1), More preferably, it is 8-30 mass%, More preferably, it is 10-20 mass%, Most preferably, it is 12-18 mass%. When the content exceeds 40% by mass, the heat resistance may not be sufficient, and it may be difficult to process the first resin layer. On the other hand, if the content is less than 5% by mass, flexibility may not be sufficient.

  The rubbery polymer (a1) constituting the rubber-reinforced aromatic vinyl resin (I-1-1) is not particularly limited as long as it is rubbery at room temperature, and either a homopolymer or a copolymer may be used. Good. Further, the rubbery polymer (a1) may be either a crosslinked polymer or a non-crosslinked polymer.

  The rubbery polymer (a1) may be either a diene polymer or a non-diene polymer, and may be used in combination. Diene polymers include homopolymers such as polybutadiene and polyisoprene; styrene / butadiene random copolymers, styrene / butadiene block copolymers, styrene / isoprene random copolymers, styrene / isoprene block copolymers, butadiene -An acrylonitrile copolymer, natural rubber, etc. are mentioned. Non-diene polymers include acrylic rubbers; ethylene / α-olefin copolymer rubbers containing ethylene units and structural units derived from α-olefins having 3 or more carbon atoms; conjugated diene compounds Examples include hydrogenated conjugated diene rubbers obtained by hydrogenating (co) polymers containing derived structural units; urethane rubbers; silicone rubbers; silicone / acrylic composite rubbers. These polymers can be used alone or in combination of two or more.

  As the rubbery polymer (a1), acrylic rubber, ethylene / α-olefin rubber and hydrogenated conjugated diene rubber are preferable from the viewpoint of weather resistance.

As said acrylic rubber, 80 mass% or more is included with respect to the whole quantity of the structural unit which comprises the said acrylic rubber for the structural unit derived from the alkyl group C2-C8 acrylic acid alkyl ester (co). Polymers are preferred.
Examples of the alkyl acrylate ester having 2 to 8 carbon atoms in the alkyl group include ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, n-octyl acrylate, and 2-ethylhexyl acrylate. Etc. These may be used alone or in combination of two or more. Preferred alkyl acrylates are 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-based compounds such as 1,3-butadiene Crosslinkable monomer such as things 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 acrylic rubber is produced by a known method, but a preferred production method is an emulsion polymerization method.

  The ethylene / α-olefin rubber is a copolymer containing an ethylene unit and one or more structural units derived from an α-olefin having 3 or more carbon atoms, and is an ethylene / propylene copolymer, ethylene / butene. Ethylene / α-olefin copolymer such as ethylene-1 copolymer; ethylene / α-olefin / nonconjugated diene such as ethylene / propylene / nonconjugated diene copolymer, ethylene / butene-1 / nonconjugated diene copolymer, etc. A copolymer etc. are mentioned.

  The α-olefin is preferably an α-olefin having 3 to 20 carbon atoms, specifically, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1 -Heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 1-eicocene and the like. In the α-olefin, a more preferable carbon number is 3 to 12, and further preferably 3 to 8. When there are too many carbon numbers, the surface external appearance property of a resin layer may fall.

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

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

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

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

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

The aromatic vinyl compound used for forming the polymer blocks A and D constituting the block copolymer is not particularly limited as long as it is a compound having at least one vinyl bond and at least one aromatic ring. No. Examples thereof include styrene, α-methylstyrene, methylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, fluorostyrene, p-tert-butylstyrene, ethylstyrene, vinylnaphthalene, and the like. . These compounds can be used alone or in combination of two or more. Of these, styrene is preferred.
The content ratio of the polymer block A constituting the block copolymer is preferably 0 to 65% by mass, more preferably 10 to 40% by mass with respect to the whole polymer. When there is too much content of the polymer block A, impact resistance may not be enough.

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

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

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

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

  The shape of the rubbery polymer (a1) 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. If the volume average particle diameter is in the above range, the processability of the thermoplastic resin composition and the impact resistance of the resulting 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 (a1) 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, The thing enlarged by the well-known method described in 56-167704 gazette etc. can also be used.

  The vinyl monomer (b11) used for forming the rubber-reinforced aromatic vinyl resin (I-1-1) contains an aromatic vinyl compound. That is, this vinyl monomer (b11) may be composed only of an aromatic vinyl compound, or composed of an aromatic vinyl compound and another monomer copolymerizable with this compound. Also good. 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, and epoxy group-containing unsaturated compounds. Compounds, oxazoline group-containing unsaturated compounds, and the like. 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. These compounds can be used alone or in combination of two or more. Of these, acrylonitrile is preferred.

  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. In addition, as another method for introducing a monomer 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 imide It is also possible to use a method.

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, 3-hydroxy-1-propene, 4-hydroxy-1-butene, cis-4-hydroxy-2-butene, trans-4-hydroxy- 2-butene, 3-hydroxy-2-me Examples include til-1-propene. 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.
Examples of the oxazoline group-containing unsaturated compound include vinyl oxazoline.

  In the present invention, the vinyl monomer (b11) preferably contains an aromatic vinyl compound and a vinyl cyanide compound, and the total amount used thereof is molding processability, chemical resistance, hydrolysis resistance, molding From the viewpoint of appearance and the like, the amount is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, based on the total amount of the vinyl monomer (b11). In addition, the use ratio of the aromatic vinyl compound and the vinyl cyanide compound is, from the viewpoint of molding processability, chemical resistance, hydrolysis resistance, molding appearance, etc. Preferably they are 5-95 mass% and 5-95 mass%, More preferably, they are 50-95 mass% and 5-50 mass%, More preferably, they are 60-95 mass% and 5-40 mass%.

  The vinyl monomer (b11) can impart heat resistance to the first resin layer by including a maleimide compound. The preferable content of the structural unit derived from the maleimide compound contained in the aromatic vinyl resin (I-1) will be described later.

As the rubber-reinforced aromatic vinyl resin (I-1-1), preferred resins are as follows.
[1] A rubber-reinforced aromatic vinyl resin obtained by polymerizing a vinyl monomer (b11) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of the rubbery polymer (a1) [2 A rubber-reinforced aromatic vinyl resin obtained by polymerizing a vinyl monomer (b11) comprising an aromatic vinyl compound, a vinyl cyanide compound and a maleimide compound in the presence of the rubbery polymer (a1) [3] A rubber-reinforced aromatic obtained by polymerizing a vinyl monomer (b11) comprising an aromatic vinyl compound, a vinyl cyanide compound and a methacrylic ester compound in the presence of the rubbery polymer (a1). Vinyl resin

  The rubber-reinforced aromatic vinyl resin (I-1-1) can be produced by polymerizing the vinyl monomer (b11) in the presence of the rubber polymer (a1). As a polymerization method, emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, or a combination of these can be used.

  In the production of the rubber-reinforced aromatic vinyl resin (I-1-1), the rubber polymer (a1) and the vinyl monomer (b11) In the presence of the total amount of the polymer (a1), the vinyl monomer (b11) may be added all at once to initiate the polymerization, or the polymerization may be carried out while being divided or continuously added. Further, in the presence or absence of a part of the rubber polymer (a1), the vinyl monomer (b11) 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 rubber-like polymer (a1) may be added all at once during the reaction, divided or continuously.

  When the rubber-reinforced aromatic vinyl resin (I-1-1) 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 (b11) 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 (b11).
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 (b11) whole quantity.

Emulsion polymerization can be carried out under known conditions depending on the type of vinyl monomer (b11), 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.
When two or more kinds of rubber-reinforced aromatic vinyl resins (I-1-1) are contained in the aromatic vinyl resin (I-1), the resin is isolated from each latex and then mixed. However, as another method, there is a method of coagulating a latex mixture containing each resin.

  A known method can be applied to the method for producing the rubber-reinforced aromatic vinyl resin (I-1-1) by solution polymerization, bulk polymerization, and bulk-suspension polymerization.

  The graft ratio of the rubber-reinforced aromatic vinyl resin (I-1-1) is preferably 20 to 170%, more preferably 30 to 170%, and still more preferably 40 to 150%. When this graft ratio is too low, the flexibility as a film may not be sufficient. On the other hand, if the graft ratio is too high, the viscosity of the first thermoplastic resin composition obtained by melt-kneading the first raw material composition may increase, 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 (I-1-1) in 20 ml of acetone (acetonitrile in the case of acrylic rubber) and is shaken under a temperature condition of 25 ° C. After shaking for 2 hours, the mixture is centrifuged for 60 minutes in a centrifuge (rotation speed: 23,000 rpm) under a temperature condition of 5 ° C., and the mass of the insoluble matter obtained by separating the insoluble matter and the soluble matter. (G), and T is the mass (g) of the rubbery polymer contained in 1 gram of the rubber-reinforced aromatic vinyl resin (I-1-1). The mass of the rubber-like polymer (a1) can be obtained by a method of calculating from the polymerization prescription and the polymerization conversion rate, a method of obtaining from the infrared absorption spectrum (IR), and the like.

  The rubber-reinforced aromatic vinyl resin (I-1-1) can be used alone or in combination of two or more.

  Next, when the aromatic vinyl resin is a mixture of the rubber-reinforced aromatic vinyl resin (I-1-1) and the (co) polymer (I-1-2), this (co) The polymer (I-1-2) is a (co) polymer obtained by polymerizing a vinyl monomer (b12) containing an aromatic vinyl compound in the absence of a rubbery polymer. There is no particular limitation. That is, the (co) polymer (I-1-2) may be either a homopolymer or a copolymer, or a combination thereof.

  The vinyl monomer (b12) 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, and epoxy group-containing unsaturated compounds. Compounds, oxazoline group-containing unsaturated compounds, and the like. These can be used alone or in combination of two or more. The compound illustrated in the said vinyl monomer (b11) is applied to each said compound.

The (co) polymer (I-1-2) is preferably a copolymer. In the present invention, the vinyl monomer (b12) 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 (b12) contains an aromatic vinyl compound and a vinyl cyanide compound, the total amount thereof is preferably 40 to 100 mass with respect to the entire vinyl monomer (b12). %, More preferably 50 to 100% by mass. In addition, the use ratio of the aromatic vinyl compound and the vinyl cyanide compound is, in terms of molding processability, chemical resistance, hydrolysis resistance, molding appearance, etc. Preferably they are 5-95 mass% and 5-95 mass%, More preferably, they are 40-95 mass% and 5-60 mass%, More preferably, they are 50-90 mass% and 10-50 mass%.

When the (co) polymer (I-1-2) 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 (co) polymer (I-1-2) is the above embodiment [1], the content ratio of the structural unit (s) and the structural unit (t) is determined by molding processability, chemical resistance, and hydrolysis resistance. From the viewpoints of properties, molding appearance, etc., when these totals are 100% by mass, preferably 5 to 95% by mass and 5 to 95% by mass, more preferably 40 to 95% by mass and 5 to 60% by mass, respectively. %, More preferably 50 to 90% by mass and 10 to 50% by mass.
Examples of the copolymer of the above embodiment [1] include acrylonitrile / styrene copolymer, acrylonitrile / α-methylstyrene copolymer, and the like.

When the (co) polymer (I-1-2) is the above embodiment [2], the content ratio of the structural unit (s), the structural unit (t), and the structural unit (u) is determined by molding processability and heat resistance. From the viewpoints of properties, chemical resistance, hydrolysis resistance, flexibility, etc., when these are 100% by mass, preferably 20 to 90% by mass, 5 to 50% by mass, and 1 to 40% by mass, respectively. %, More preferably 25 to 85 mass%, 10 to 45 mass% and 5 to 35 mass%, still more preferably 30 to 80 mass%, 10 to 40 mass% and 10 to 30 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 (co) polymer (I-1-2) can be produced by polymerizing a vinyl monomer (b12) 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 rubber reinforced aromatic vinyl-type resin (I-1-1) 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 (b12) whole quantity.
In addition, the chain transfer agent, emulsifier, etc. which can be used at the time of manufacture of the said rubber reinforced aromatic vinyl-type resin (I-1-1) can be used as needed.

  In the production of the (co) polymer (I-1-2), the polymerization may be started in a state where the entire amount of the vinyl monomer (b12) is accommodated in the reaction system, and is 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 (co) polymer (I-1-2) can be used individually by 1 type or in combination of 2 or more types.

  When the aromatic vinyl resin (I-1) is composed of a rubber-reinforced aromatic vinyl resin (I-1-1), and the rubber-reinforced aromatic vinyl resin (I-1-1) and (co-polymer) ) Acetone of the aromatic vinyl resin (I-1) in any case where the polymer (I-1-2) is a mixture (provided that the rubbery polymer is an acrylic rubber) Intrinsic viscosity [η] (measured in methyl ethyl ketone at 30 ° C.) of the component soluble in acetonitrile) is preferably 0.1 to 2.5 dl / g, more preferably 0.2 to 1.5 dl / g, More preferably, it is 0.25 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.
Acetone-soluble matter (rubbery) recovered after centrifugation when determining the graft ratio in the aromatic vinyl resin (I-1) (including rubber-reinforced aromatic vinyl resin (I-1-1)) If the polymer is an acrylic rubber, dissolve the acetonitrile soluble component) in methyl ethyl ketone, prepare 5 samples with different concentrations, and measure the reduced viscosity at each concentration at 30 ° C using an Ubbelohde viscometer. Viscosity [η] is determined.

The above-mentioned graft ratio and intrinsic viscosity [η] are the polymerization initiation used when producing the rubber-reinforced aromatic vinyl resin (I-1-1) and the (co) polymer (I-1-2). It can be easily controlled by adjusting the type and amount of the agent, chain transfer agent, emulsifier, solvent, etc., and further the polymerization time, polymerization temperature and the like.
Further, the intrinsic viscosity [η] of the aromatic vinyl resin (I-1) is a rubber-reinforced aromatic vinyl resin (I-1-1) and (co) polymer having different intrinsic viscosities [η] ( I-1-2) can also be adjusted by selecting as appropriate.

In the case of imparting sufficient heat resistance to the first resin layer, the aromatic vinyl resin (I-1) preferably includes a structural unit (u) derived from a maleimide compound. This structural unit (u) may be derived from the rubber-reinforced aromatic vinyl resin (I-1-1) or derived from the (co) polymer (I-1-2). May be. 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 40% by mass, when the aromatic vinyl resin (I-1) is 100% by mass, More preferably, it is 3-35 mass%, More preferably, it is 5-30 mass%. When there is too much content of the said structural unit (u), the flexibility of a 1st resin layer may fall.

  The saturated polyester resin is not particularly limited as long as it has an ester bond in the main chain of the molecule, but the saturated polyester resin may be a homopolymerized polyester or a copolyester. .

Examples of the saturated polyester resin include 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.
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 saturated polyester resin is a copolymerized polyester, examples of the copolymerizable monomer used for the formation thereof include linear alkylene glycols such as ethylene glycol, propylene glycol, and 1,4-butanediol. Polyoxyalkylene glycols having a poly (oxy-alkylene) unit such as alkylene glycol, diethylene glycol, etc. and having an oxyalkylene unit having about 2 to 4 repetitions, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc. And 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 saturated polyester resin include polyalkylenes 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 polyalkylene naphthalate such as terephthalate, polyethylene isophthalate, polyethylene naphthalate, polybutylene naphthalate, polyhexamethylene naphthalate, copolymerized polyester mainly containing alkylene terephthalate unit and / or alkylene naphthalate unit, Examples thereof include liquid crystal 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 monomer unit derived from an α-olefin having 2 or more carbon atoms. A preferable olefin resin is a polymer containing a monomer unit composed of an α-olefin having 2 to 10 carbon atoms. Therefore, as the olefin-based resin, a (co) polymer mainly containing one or more monomer units composed of an α-olefin having 2 to 10 carbon atoms; a single amount composed of an α-olefin having 2 to 10 carbon atoms Examples thereof include a copolymer mainly containing at least one kind of body unit and at least one kind of monomer 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 can 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 monomer units constituting the olefin resin include 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 7-methyl-1, Non-conjugated dienes such as 6-octadiene and 1,9-decadiene are exemplified. These can 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, it is 0.05 to 100 g / 10 min and has a molecular weight corresponding to each value.

〔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 first 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 first raw material composition is preferably 0.05 to 20 parts by mass, more preferably 0.00 with respect to 100 parts by mass of the thermoplastic resin (I). It is 07-15 mass parts, More preferably, it is 0.1-10 mass parts. 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, the external appearance of the back surface protective film for solar cells of this invention provided with the 1st resin layer obtained may fall. On the other hand, when there is too little said content, it exists in the tendency for adhesiveness with the said filler part to fall.

  The said 1st raw material composition can contain an additive according to the objective, a use, etc. The additives include colorants, antioxidants, UV absorbers, anti-aging agents, fluorescent brighteners, weathering agents, fillers, antistatic agents, flame retardants, antifogging agents, antibacterial agents, fungicides, Antifouling agents, tackifiers and the like can be mentioned. Specific compounds and their blending amounts in these additives will be described later together with preferred embodiments of the back surface protective film for solar cells of the present invention.

The first resin layer is a layer obtained by using a first thermoplastic resin composition obtained by melt-kneading a first raw material composition containing a thermoplastic resin (I) and a silane coupling agent.
The melt kneading method of the first raw material composition is not particularly limited, and is a method of melt kneading all components including the thermoplastic resin (I) and the silane coupling agent; the thermoplastic resin (I) and the silane coupling agent. A method in which other raw material components are added separately or continuously while melt kneading and the melt kneading is continued; a silane coupling agent while melt kneading the thermoplastic resin (I) and other raw material components In which the silane coupling agent and other raw material components are added in portions or continuously while melt-kneading the thermoplastic resin (I). And a method of continuing the melt-kneading.
Examples of the apparatus used for melt kneading include a single screw extruder, a twin screw extruder, a Banbury mixer, a kneader, and a continuous kneader.
The thickness of the first resin layer is usually 5 to 500 μm, preferably 10 to 400 μm.

  As described above, the second resin layer is a base layer in the solar cell back surface protective film of the present invention, and preferably a second raw material composition obtained by melt-kneading the second raw material composition containing the thermoplastic resin (II). It is a layer obtained by using a thermoplastic resin composition.

  From the viewpoint of imparting sufficient flexibility and heat resistance to the back surface protective film for solar cells of the present invention, further, printing, surface treatment, etc. on the third resin layer or a layer disposed on the back side thereof as necessary , The glass transition temperature (Tg) of the thermoplastic resin (II) is preferably 120 ° C. or higher, more preferably 120 ° C. to 120 ° C. from the viewpoint of suppressing thermal shrinkage when receiving a temperature history or the like. It is 220 degreeC, More preferably, it is 130 to 190 degreeC, More preferably, it is 140 to 170 degreeC, Most preferably, it is 145 to 160 degreeC.

The thermoplastic resin (II) is not particularly limited as long as it is a thermoplastic resin. Aromatic vinyl resin, polyolefin resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin Saturated polyester resin, polycarbonate resin, acrylic resin, fluororesin, ethylene / vinyl acetate resin and the like. These can be used alone or in combination of two or more.
About these resins, the description in the said thermoplastic resin (I) is applied.
As said thermoplastic resin (II), aromatic vinyl-type resin, saturated polyester-type resin, and olefin resin are preferable, and aromatic vinyl-type resin is especially preferable. When the thermoplastic resin (II) contains an aromatic vinyl resin, it is excellent in hydrolysis resistance.
The thermoplastic resin (II) may be the same as or different from the thermoplastic resin (I).

  The aromatic vinyl resin (hereinafter also referred to as “component (II-1)”) is typically a vinyl monomer containing an aromatic vinyl compound in the presence of the rubbery polymer (a2). Rubber-reinforced aromatic vinyl resin (II-1-1) obtained by polymerizing body (b21), (co) polymer of vinyl monomer (b22) containing an aromatic vinyl compound (II-1-2) ), And a mixture of rubber-reinforced aromatic vinyl resin (II-1-1) and (co) polymer (II-1-2). The component (II-1) is a mixture of rubber-reinforced aromatic vinyl resin (II-1-1) and (co) polymer (II-1-2) from the viewpoint of impact resistance and flexibility. Is preferred. The rubber-reinforced aromatic vinyl resin (II-1-1) and the (co) polymer (II-1-2) are produced by the above-described rubber-reinforced aromatic vinyl resin (I-1-1) and This is the same as the method for producing the (co) polymer (I-1-2).

  As the rubbery polymer (a2) forming the rubber-reinforced aromatic vinyl resin (II-1-1), those described as the rubbery polymer (a1) can be used. The polymers (a1) and (a2) may be the same as or different from each other. Preferred rubbery polymers (a2) are acrylic rubber, ethylene / α-olefin rubber, hydrogenated conjugated diene rubber, silicone rubber and silicone / acrylic composite rubber from the viewpoint of weather resistance.

As the vinyl monomer (b21) forming the rubber-reinforced aromatic vinyl resin (II-1-1), those described as the vinyl monomer (b11) can be used. The vinyl monomers (b11) and (b21) may be the same as or different from each other. Preferred vinyl monomers (b21) are an aromatic vinyl compound and a vinyl cyanide compound. As the aromatic vinyl compound, styrene and α-methylstyrene are preferable, and as the vinyl cyanide compound, acrylonitrile is preferable.
In the vinyl monomer (b21), the total amount of the aromatic vinyl compound and the vinyl cyanide compound used is a vinyl-based monomer from the viewpoint of molding processability, chemical resistance, hydrolysis resistance, molding appearance, and the like. Preferably it is 70-100 mass% with respect to the whole quantity of a monomer (b21), More preferably, it is 80-100 mass%. In addition, the use ratio of the aromatic vinyl compound and the vinyl cyanide compound is, from the viewpoint of molding processability, chemical resistance, hydrolysis resistance, molding appearance, etc. Preferably they are 5-95 mass% and 5-95 mass%, More preferably, they are 50-95 mass% and 5-50 mass%, More preferably, they are 60-90 mass% and 10-40 mass%.

  Moreover, the said vinylic monomer (b21) can provide heat resistance to a 2nd resin layer by including a maleimide type compound. The preferable content of the structural unit derived from the maleimide compound contained in the aromatic vinyl resin (II-1) will be described later.

As the rubber-reinforced aromatic vinyl resin (II-1-1), preferred resins are as follows.
[1] A rubber-reinforced aromatic vinyl resin [2] obtained by polymerizing a vinyl monomer (b21) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of the rubbery polymer (a2) [2] A rubber-reinforced aromatic vinyl resin obtained by polymerizing a vinyl monomer (b21) comprising an aromatic vinyl compound, a vinyl cyanide compound and a maleimide compound in the presence of the rubbery polymer (a2) [3] A rubber-reinforced aromatic obtained by polymerizing a vinyl monomer (b21) comprising an aromatic vinyl compound, a vinyl cyanide compound and a methacrylic ester compound in the presence of the rubbery polymer (a2). Vinyl resin

  The graft ratio of the rubber-reinforced aromatic vinyl resin (II-1-1) is preferably 20 to 170%, more preferably 30 to 170%, and still more preferably 40 to 150%. When this graft ratio is too low, the flexibility as a film may not be sufficient. On the other hand, if the graft ratio is too high, the viscosity of the thermoplastic resin composition obtained by melt-kneading the second raw material composition may increase, and it may be difficult to reduce the thickness.

  The rubber-reinforced aromatic vinyl resin (II-1-1) can be used alone or in combination of two or more.

  As the vinyl monomer (b22) forming the (co) polymer (II-1-2), those described as the vinyl monomer (b12) can be used. Monomers (b12) and (b22) may be the same as or different from each other.

The (co) polymer (II-1-2) is preferably a copolymer. In the present invention, the vinyl monomer (b22) 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 (b22) contains an aromatic vinyl compound and a vinyl cyanide compound, the total amount thereof is preferably 40 to 100 mass with respect to the entire vinyl monomer (b22). %, More preferably 50 to 100% by mass. In addition, the use ratio of the aromatic vinyl compound and the vinyl cyanide compound is, in terms of molding processability, chemical resistance, hydrolysis resistance, molding appearance, etc. Preferably they are 5-95 mass% and 5-95 mass%, More preferably, they are 40-95 mass% and 5-60 mass%, More preferably, they are 50-90 mass% and 10-50 mass%.

When the (co) polymer (II-1-2) is a copolymer, preferred polymers are as follows.
[1] A copolymer comprising a structural unit (s) derived from an aromatic vinyl compound and a structural unit (t) derived from a vinyl cyanide compound [2] a structural unit (s) derived from an aromatic vinyl compound And a structural unit (t) derived from a vinyl cyanide compound and a structural unit (u) derived from a maleimide compound

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

  When the aromatic vinyl resin (II-1) is made of a rubber-reinforced aromatic vinyl resin (II-1-1), and the rubber-reinforced aromatic vinyl resin (II-1-1) and (co-polymer) ) Acetone of this aromatic vinyl resin (II-1) in any case where it is composed of a mixture of polymers (II-1-2) (provided that the rubbery polymer is an acrylic rubber) Intrinsic viscosity [η] (measured in methyl ethyl ketone at 30 ° C.) of the component soluble in acetonitrile) is preferably 0.1 to 2.5 dl / g, more preferably 0.2 to 1.5 dl / g, More preferably, it is 0.25 to 1.2 dl / g. When the intrinsic viscosity [η] is within the above range, the processability of the second thermoplastic resin composition is excellent, and the thickness accuracy of the second resin layer is also excellent.

In the case of imparting sufficient heat resistance to the second resin layer, the aromatic vinyl resin (II-1) preferably includes a structural unit (u) derived from a maleimide compound. This structural unit (u) may be derived from the rubber-reinforced aromatic vinyl resin (II-1-1) or derived from the (co) polymer (II-1-2). May be. Moreover, you may originate in both.
The content of the structural unit (u) for making the second resin layer excellent in heat resistance is preferably 1 to 50% by mass, when the aromatic vinyl resin (II-1) is 100% by mass, More preferably, it is 5-45 mass%, More preferably, it is 10-40 mass%. When there is too much content of the said structural unit (u), the flexibility of a 2nd resin layer may fall.

  When the thermoplastic resin (II) constituting the second resin layer contains a saturated polyester resin, an olefin resin, etc., the explanation of each resin in the thermoplastic resin (I) is also applied to these resins. The

  The said 2nd raw material composition can contain an additive according to the objective, a use, etc. The additives include colorants, antioxidants, UV absorbers, anti-aging agents, fluorescent brighteners, weathering agents, fillers, antistatic agents, flame retardants, antifogging agents, antibacterial agents, fungicides, Antifouling agents, tackifiers, silane coupling agents and the like can be mentioned. As a silane coupling agent, what was described as said General formula (1) can be used, and content in a 2nd raw material composition can also be made the same as that in the said 1st raw material composition. Moreover, the specific compound in other additives and its compounding quantity are mentioned later with the preferable aspect of the back surface protection film for solar cells of this invention.

The second thermoplastic resin composition used for forming the second resin layer is a composition formed by melt-kneading the second raw material composition containing the thermoplastic resin (II).
The melt kneading method of the second raw material composition is not particularly limited, and a known method can be applied.
The thickness of the second resin layer is usually 10 to 990 μm, preferably 20 to 500 μm.

  As described above, the third resin layer is a layer having an effect of imparting flexibility to the back surface protective film for solar cell of the present invention. Preferably, the third resin layer is obtained by melt-kneading the third raw material composition. It is a layer obtained by using a thermoplastic resin composition.

  The glass transition temperature (Tg) of the thermoplastic resin (III) is preferably from the viewpoint of imparting sufficient flexibility to the back surface protective film for solar cells of the present invention and imparting heat resistance to the third resin layer. It is 90 ° C to 200 ° C, more preferably 95 ° C to 160 ° C, still more preferably 95 ° C to 150 ° C, and particularly preferably 110 ° C to 140 ° C.

The thermoplastic resin (III) is not particularly limited as long as it is a thermoplastic resin. Aromatic vinyl resin, polyolefin resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin Saturated polyester resin, polycarbonate resin, acrylic resin, fluororesin, ethylene / vinyl acetate resin and the like. These can be used alone or in combination of two or more.
About these resins, the description in the said thermoplastic resin (I) is applied.
As said thermoplastic resin (III), aromatic vinyl-type resin, saturated polyester-type resin, and olefin resin are preferable, and aromatic vinyl-type resin is especially preferable. When the thermoplastic resin (III) contains an aromatic vinyl resin, it is excellent in hydrolysis resistance.
The thermoplastic resin (III) may be the same as or different from the thermoplastic resin (I). The thermoplastic resin (III) may be the same as or different from the thermoplastic resin (II).

  The aromatic vinyl resin (hereinafter also referred to as “component (III-1)”) is typically a vinyl monomer containing an aromatic vinyl compound in the presence of the rubbery polymer (a3). A rubber-reinforced aromatic vinyl resin (III-1-1) obtained by polymerizing the body (b31), a (co) polymer (III-1-2) of a vinyl monomer (b32) containing an aromatic vinyl compound And a mixture of rubber-reinforced aromatic vinyl resin (III-1-1) and (co) polymer (III-1-2). The component (III-1) is a mixture of rubber-reinforced aromatic vinyl resin (III-1-1) and (co) polymer (III-1-2) from the viewpoint of impact resistance and flexibility. Is preferred. The rubber-reinforced aromatic vinyl resin (III-1-1) and the (co) polymer (III-1-2) are produced by the above-described rubber-reinforced aromatic vinyl resin (I-1-1) and This is the same as the method for producing the (co) polymer (I-1-2).

  As the rubbery polymer (a3) forming the rubber-reinforced aromatic vinyl resin (III-1-1), those described as the rubbery polymer (a1) can be used. The polymers (a1) and (a3) may be the same as or different from each other. The rubber polymers (a2) and (a3) may be the same as or different from each other. Preferred rubbery polymers (a3) are acrylic rubber, ethylene / α-olefin rubber, hydrogenated conjugated diene rubber, silicone rubber and silicone / acrylic composite rubber from the viewpoint of weather resistance.

As the vinyl monomer (b31) forming the rubber-reinforced aromatic vinyl resin (III-1-1), those described as the vinyl monomer (b11) can be used. The vinyl monomers (b11) and (b31) may be the same as or different from each other. The vinyl monomers (b21) and (b31) may be the same as or different from each other. Preferred vinyl monomers (b31) are an aromatic vinyl compound and a vinyl cyanide compound. As the aromatic vinyl compound, styrene and α-methylstyrene are preferable, and as the vinyl cyanide compound, acrylonitrile is preferable.
In the vinyl monomer (b31), the total use amount of the aromatic vinyl compound and the vinyl cyanide compound is a vinyl type monomer from the viewpoint of molding processability, chemical resistance, hydrolysis resistance, molding appearance, and the like. Preferably it is 70-100 mass% with respect to the whole quantity of a monomer (b31), More preferably, it is 80-100 mass%. In addition, the use ratio of the aromatic vinyl compound and the vinyl cyanide compound is, from the viewpoint of molding processability, chemical resistance, hydrolysis resistance, molding appearance, etc. Preferably they are 5-95 mass% and 5-95 mass%, More preferably, they are 50-95 mass% and 5-50 mass%, More preferably, they are 60-90 mass% and 10-40 mass%.

  The vinyl monomer (b31) can impart heat resistance to the 33rd resin layer by including a maleimide compound. Preferable content of the structural unit derived from the maleimide compound contained in the aromatic vinyl resin (III-1) will be described later.

As the rubber-reinforced aromatic vinyl resin (III-1-1), preferred resins are as follows.
[1] A rubber-reinforced aromatic vinyl resin [2] obtained by polymerizing a vinyl monomer (b31) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of the rubbery polymer (a3). A rubber-reinforced aromatic vinyl resin obtained by polymerizing a vinyl monomer (b31) comprising an aromatic vinyl compound, a vinyl cyanide compound and a maleimide compound in the presence of the rubber polymer (a3) [3] A rubber-reinforced aromatic obtained by polymerizing a vinyl monomer (b31) comprising an aromatic vinyl compound, a vinyl cyanide compound and a methacrylic ester compound in the presence of the rubbery polymer (a3). Vinyl resin

  The graft ratio of the rubber-reinforced aromatic vinyl resin (III-1-1) is preferably 20 to 170%, more preferably 30 to 170%, and still more preferably 40 to 150%. When this graft ratio is too low, the flexibility as a film may not be sufficient. On the other hand, if the graft ratio is too high, the viscosity of the thermoplastic resin composition obtained by melt-kneading the third raw material composition becomes high, and it may be difficult to reduce the thickness.

  The rubber-reinforced aromatic vinyl resin (III-1-1) can be used alone or in combination of two or more.

  As the vinyl monomer (b32) forming the (co) polymer (III-1-2), those described as the vinyl monomer (b12) can be used. Monomers (b12) and (b32) may be the same as or different from each other. The vinyl monomers (b22) and (b32) may be the same as or different from each other.

The (co) polymer (III-1-2) is preferably a copolymer. In the present invention, the vinyl monomer (b32) 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 (b32) contains an aromatic vinyl compound and a vinyl cyanide compound, the total amount thereof is preferably 40 to 100 mass with respect to the entire vinyl monomer (b32). %, More preferably 50 to 100% by mass. In addition, the use ratio of the aromatic vinyl compound and the vinyl cyanide compound is, in terms of molding processability, chemical resistance, hydrolysis resistance, molding appearance, etc. Preferably they are 5-95 mass% and 5-95 mass%, More preferably, they are 40-95 mass% and 5-60 mass%, More preferably, they are 50-90 mass% and 10-50 mass%.

When the (co) polymer (III-1-2) is a copolymer, preferred polymers are as follows.
[1] A copolymer comprising a structural unit (s) derived from an aromatic vinyl compound and a structural unit (t) derived from a vinyl cyanide compound [2] a structural unit (s) derived from an aromatic vinyl compound And a structural unit (t) derived from a vinyl cyanide compound and a structural unit (u) derived from a maleimide compound

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

  When the aromatic vinyl resin (III-1) is composed of a rubber-reinforced aromatic vinyl resin (III-1-1), and the rubber-reinforced aromatic vinyl resin (II-1-1) and (co-polymer) ) Acetone of the aromatic vinyl resin (III-1) in any case where the polymer (III-1-2) is a mixture (provided that the rubbery polymer is an acrylic rubber) Intrinsic viscosity [η] (measured in methyl ethyl ketone at 30 ° C.) of the component soluble in acetonitrile) is preferably 0.1 to 2.5 dl / g, more preferably 0.2 to 1.5 dl / g, More preferably, it is 0.25 to 1.2 dl / g. When the intrinsic viscosity [η] is within the above range, the third thermoplastic resin composition is excellent in molding processability and the thickness accuracy of the third resin layer is also excellent.

In the case of imparting sufficient heat resistance to the third resin layer, the aromatic vinyl resin (III-1) preferably includes a structural unit (u) derived from a maleimide compound. This structural unit (u) may be derived from the rubber-reinforced aromatic vinyl resin (III-1-1) or derived from the (co) polymer (III-1-2). May be. Moreover, you may originate in both.
The content of the structural unit (u) for making the third resin layer excellent in heat resistance is preferably 1 to 40% by mass when the aromatic vinyl resin (III-1) is 100% by mass, More preferably, it is 3-35 mass%, More preferably, it is 5-30 mass%. When there is too much content of the said structural unit (u), the flexibility of the 3rd resin layer may fall.

  When the thermoplastic resin (III) constituting the third resin layer contains a saturated polyester resin, an olefin resin, etc., the explanation of each resin in the thermoplastic resin (I) is applied to these resins as well. The

  The said 3rd raw material composition can contain an additive according to the objective, a use, etc. The additives include colorants, antioxidants, UV absorbers, anti-aging agents, fluorescent brighteners, weathering agents, fillers, antistatic agents, flame retardants, antifogging agents, antibacterial agents, fungicides, Antifouling agents, tackifiers, silane coupling agents and the like can be mentioned. As a silane coupling agent, what was described as said General formula (1) can be used, and content in a 3rd raw material composition can also be made to be the same as that in the said 1st raw material composition. Moreover, the specific compound in other additives and its compounding quantity are mentioned later with the preferable aspect of the back surface protection film for solar cells of this invention.

The third thermoplastic resin composition used for forming the third resin layer is a composition obtained by melt-kneading the third raw material composition containing the thermoplastic resin (III).
The melt kneading method of the third raw material composition is not particularly limited, and a known method can be applied.
The thickness of the third resin layer is usually 5 to 500 μm, preferably 10 to 400 μm.

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

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

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 each thermoplastic resin contained in the first raw material composition, the second raw material composition, and the third raw material composition. It is.

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 each thermoplastic resin contained in the first raw material composition, the second raw material composition, and the third raw material composition. It is.

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 each thermoplastic resin contained in the first raw material composition, the second raw material composition, and the third raw material composition. is there.

  In the back surface protective film for a solar cell of the present invention, the first resin layer uses a first thermoplastic resin composition obtained by melt-kneading a raw material composition containing a thermoplastic resin (I) and a silane coupling agent. Since it is an obtained layer, the first resin layer and the solar cell element are provided on the surface on the first resin layer side without providing an adhesive layer for adhering to the filler material embedding the solar cell element. Is excellent in adhesiveness with a filler part containing an ethylene / vinyl acetate copolymer composition and the like. And the back surface protection film for solar cells of this invention is made to adhere | attach with the exposed surface of the said filler part in the surface (upper surface side) of the 1st resin layer 11 shown by FIG.1 and FIG.2. Manufactured.

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

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

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

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

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

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

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

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

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

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

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

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

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

In the said film (Y), in the film which comprises a 1st resin layer, the transmittance | permeability with respect to the light of wavelength 800-1400nm shall be 60% or more, and the absorption factor with respect to the light of wavelength 400-700 nm shall be 60% or more. Furthermore, the film constituting the first resin layer preferably has a property of absorbing visible light and transmitting infrared light.
Therefore, the 1st thermoplastic resin composition which comprises the 1st resin layer which satisfies the said property has a property which absorbs visible rays and transmits a thermoplastic resin (I), a silane coupling agent, and infrared rays. A composition obtained by melt-kneading a first raw material composition containing a colorant (hereinafter referred to as “infrared transparent colorant”) is preferable.

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

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

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

〔式中、Ｒ^７及びＲ^８は、互いに同一又は異なって、フェニレン基、３−メトキシフェニレン基、４−メトキシフェニレン基、４−エトキシフェニレン基、炭素数１〜３のアルキルフェニレン基、ヒドロキシフェニレン基、４，６−ジメチルフェニレン基、３，５−ジメチルフェニレン基、３−クロロフェニレン基、４−クロロフェニレン基、５−クロロフェニレン基、３−ブロモフェニレン基、４−ブロモフェニレン基、５−ブロモフェニレン基、３−フルオロフェニレン基、４−フルオロフェニレン基、５−フルオロフェニレン基、ナフチレン基、ナフタレンジイル基、ピリジレン基、２，３−ピリジンジイル基、３，４−ピリジンジイル基、４−メチル−２，３−ピリジンジイル基、５−メチル−２，３−ピリジンジイル基、６−メチル−２，３−ピリジンジイル基、５−メチル−３，４−ピリジンジイル基、４−メトキシ−２，３−ピリジンジイル基又は４−クロロ−２，３−ピリジンジイル基である。〕 Examples of the infrared transmissive colorant include perylene pigments. As the perylene pigment, compounds represented by the following general formulas (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 masses with respect to 100 mass parts of the thermoplastic resin (I) from the viewpoints of transparency and absorbability with respect to each light. Part or less, more preferably 0.1 to 5 parts by weight.
In addition, in the said 1st resin layer, if it does not reduce the said transmittance | permeability and absorptivity, according to the objective, a use, etc., another coloring agent can be included. For example, a solar cell module having various appearances can be obtained by using a yellow pigment, a blue pigment, or the like as a colorant other than the infrared-transmitting colorant and using the following combinations.
[1] Brown coloration by combination of black-based infrared transmitting colorant and yellow pigment [2] Dark blue coloration by combination of black-based infrared transmitting colorant and blue pigment When other colorant is used, The content in the thermoplastic resin composition is usually 200 parts by mass or less, preferably 0.01 to 100 parts by mass with respect to 100 parts by mass of the infrared transmitting colorant.

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

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

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

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

A preferable aspect is shown below as a back surface protective film for solar cells of this invention.
(A) A first resin layer is obtained using a first thermoplastic resin composition obtained by melt-kneading a first raw material composition containing a thermoplastic resin (I), a silane coupling agent and a white colorant. And the second resin layer is obtained using the second thermoplastic resin composition obtained by melt-kneading the second raw material composition containing the thermoplastic resin (II) and not containing the white colorant. And the third resin layer is obtained using a third thermoplastic resin composition obtained by melt-kneading a third raw material composition containing the thermoplastic resin (III) and not containing a white colorant. A first thermoplastic resin composition obtained by melt-kneading a first raw material composition containing a thermoplastic resin (I), a silane coupling agent, and a white colorant. And the second resin layer contains the thermoplastic resin (II) and A layer obtained by using a second thermoplastic resin composition obtained by melt-kneading a second raw material composition not containing a white colorant, wherein the third resin layer comprises a thermoplastic resin (III) and a white system A film (c) first resin layer, which is a layer obtained using a third thermoplastic resin composition obtained by melt-kneading a third raw material composition containing a colorant, is a thermoplastic resin (I), a silane cup It is a layer obtained by using a first thermoplastic resin composition obtained by melt-kneading a first raw material composition containing a ring agent and a white colorant, and the second resin layer comprises thermoplastic resin (II) and A layer obtained by using a second thermoplastic resin composition obtained by melt-kneading a second raw material composition containing a white colorant, wherein the third resin layer contains a thermoplastic resin (III) and is white Third thermoplastic resin composition obtained by melt-kneading a third raw material composition containing no system colorant A film (d) first resin layer which is a layer obtained by using a first melt composition obtained by melt-kneading a first raw material composition containing a thermoplastic resin (I), a silane coupling agent and a white colorant. A second thermoplastic resin obtained by melt-kneading a second raw material composition containing a thermoplastic resin (II) and a white colorant, which is a layer obtained by using a thermoplastic resin composition A third thermoplastic resin composition obtained by melting and kneading a third raw material composition containing a thermoplastic resin (III) and a white colorant, wherein the third resin layer is a layer obtained using the composition. The film which is the layer obtained by using It is a preferable example as said film (X) above.

Moreover, a preferable example as said film (Y) is shown below.
(E) The first resin layer is obtained by using a first thermoplastic resin composition obtained by melt-kneading a first raw material composition containing a thermoplastic resin (I), a silane coupling agent and an infrared transmitting colorant. The second resin layer is obtained using a second thermoplastic resin composition obtained by melt-kneading a second raw material composition containing a thermoplastic resin (II) and no white colorant. A layer obtained by using a third thermoplastic resin composition obtained by melting and kneading a third raw material composition containing a thermoplastic resin (III) and a white colorant. A first thermoplastic resin composition obtained by melting and kneading a first raw material composition containing a thermoplastic resin (I), a silane coupling agent, and an infrared transmitting colorant. The second resin layer is a layer obtained by using thermoplastic resin (II) and white It is a layer obtained by using a second thermoplastic resin composition obtained by melt-kneading a second raw material composition containing a colorant, and the third resin layer contains a thermoplastic resin (III) and is white A film (g) first resin layer, which is a layer obtained by using a third thermoplastic resin composition obtained by melt-kneading a third raw material composition not containing a colorant, is a thermoplastic resin (I), silane It is a layer obtained by using a first thermoplastic resin composition obtained by melt-kneading a first raw material composition containing a coupling agent and an infrared transmitting colorant, and the second resin layer is a thermoplastic resin (II ) And a second raw material composition containing a white colorant. The third resin layer is a layer obtained by melting and kneading the second raw material composition, and the third resin layer is composed of thermoplastic resin (III) and white color. Third thermoplastic resin composition obtained by melt-kneading a third raw material composition containing a colorant Film is a layer obtained by using

In the back surface protective film for solar cells of the present invention, the thermoplastic resin (I) contained in the first resin layer, the thermoplastic resin (II) contained in the second resin layer, and the third resin layer The thermoplastic resins (III) to be produced are preferably of the same type. A particularly preferable resin is an aromatic vinyl-based resin, and by including this, the hydrolysis resistance, dimensional stability and impact resistance are excellent. In this case, the content ratio of the rubbery polymer contained in each resin layer may be the same as or different from each other.
When the thermoplastic resins (I), (II), and (III) are the same resin, the first thermoplastic resin composition, the second thermoplastic resin composition, and the third heat The plastic resin composition may be the same or different.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

1. Evaluation method Measurement methods for various evaluation items are shown below.
1-1. Rubber content in thermoplastic resin Calculated from the composition at the time of raw material charging.
1-2. N-phenylmaleimide unit content in thermoplastic resin 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 Tables 1 to 5) to obtain two evaluation films. A film “Ultra Pearl” (trade name, manufactured by Sanvic Co., Ltd.) having a length of 100 mm, a width of 15 mm and a thickness of 400 μm made of an ethylene / vinyl acetate copolymer is located between the first resin layers in the two evaluation films. And placed in a laminator in a laminated state. Thereafter, the upper and lower portions of the laminator were evacuated and preheated at 150 ° C. for 5 minutes. Next, the upper part was returned to atmospheric pressure and pressed for 15 minutes to obtain a sample for measuring peel strength.
In the obtained peel strength measurement sample, the peel strength was measured by peeling the T-shape from the portion where the evaluation film was not adhered to the EVA film. Moreover, the peeling state was evaluated. The peeled state was “◯” when the EVA film was broken, and “X” when broken at the interface between the EVA film and the evaluation film part.

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

1-6. Reflectance (%) for light having a wavelength of 400 to 1,400 nm and light having a wavelength of 800 to 1,400 nm
The back surface protective film for solar cells (50 mm × 50 mm, thickness is described in Tables 1 to 5) was used as a measurement sample, and the ultraviolet-visible near-infrared spectrophotometer “V-670” (model name) manufactured by JASCO Corporation was used. The reflectance was measured. 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
Measure a first resin layer film (50 mm × 50 mm, thickness is listed in Table 3 and Table 5) obtained using a first thermoplastic resin composition containing an infrared transmissive colorant (perylene-based black pigment) The transmittance was measured using an ultraviolet-visible near-infrared spectrophotometer “V-670” (model name) manufactured by JASCO Corporation as a sample. 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
Measure a first resin layer film (50 mm × 50 mm, thickness is listed in Table 3 and Table 5) obtained using a first thermoplastic resin composition containing an infrared transmitting colorant (perylene black pigment) As a sample, transmittance and reflectance were measured with an ultraviolet-visible near-infrared spectrophotometer “V-670” (model name) manufactured by JASCO Corporation. 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〜表５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 surface protective film for solar cells was cut into strips (length 200 mm, width 15 mm, thickness described in Tables 1 to 5), 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. Scratch resistance The surface on the back surface protective layer side of the back surface protective film for solar cells was subjected to 500 reciprocating frictions with a cotton canvas Kanakin No. 3 and a vertical load of 500 g using a reciprocating friction tester manufactured by Tohken Precision Industry Co., Ltd. The subsequent surface was visually observed and judged according to the following criteria.
○: No scratch was observed Δ: Scratch was slightly observed ×: Scratch was clearly observed

2. 2. Raw materials for producing a back surface protective film for solar cell 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 108 ° 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 108 ° 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.

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. Back surface protective layer forming film (P-1)
A translucent PET film “Lumirror X10S” (trade name) manufactured by Toray Industries, Inc. was used. The thickness is 50 μm.
2-14. Back surface protective layer forming film (P-2)
A milk white PET film “Melinex 238” (trade name) manufactured by Teijin DuPont was used. The thickness is 75 μm.

3. Manufacture and evaluation of back surface protection film for solar cells (1)
Example 1-1
The first raw material composition, the second raw material composition, and the third raw material composition for forming the first resin layer, the second resin layer, and the third resin layer shown in Table 1 were prepared with a Henschel mixer, respectively. did. Thereafter, using a twin screw extruder (model name “TEX44”, manufactured by Nippon Steel Works), melt kneading is performed at a barrel temperature of 270 ° C., and the first thermoplastic resin composition, the second thermoplastic resin composition, and the third heat. Three types of pellets of the plastic resin composition were obtained.
Next, the first thermoplastic resin composition is used in each extruder using a multilayer film forming machine having a T die having a die width of 1,400 mm and a lip interval of 1.5 mm and including three extruders having a screw diameter of 65 mm. The 2nd thermoplastic resin composition and the 3rd thermoplastic resin composition were supplied. Then, the molten resin was discharged from the T die at a melting temperature of 270 ° C. to obtain a three-layer soft film. Thereafter, this three-layer soft film was cooled and solidified while being in close contact with a cast roll whose surface temperature was controlled at 95 ° C. with an air knife, to obtain a back protective film for a laminated solar cell having a thickness of 800 μm. . The thicknesses of the first resin layer, the second resin layer, and the third resin layer are as shown in Table 1. Thickness gauge (model name “ID-C1112C”, manufactured by Mitutoyo Co., Ltd.) was used to cut the film after 1 hour from the start of film production. Then, the thickness was measured at intervals of 10 mm (n = 107), and the average value was obtained. Measurement point values in the range of 20 mm from the edge of the film were removed from the average calculation.
Various evaluations were performed on the solar cell back surface protective film, and the results are also shown in Table 1.

Examples 1-2 to 1-4 and Comparative Examples 1-1 to 1-2
Using the raw material composition for forming the first resin layer, the second resin layer, and the third resin layer shown in Table 1, a back surface protective film for a laminated solar cell was formed in the same manner as in Example 1-1. Obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 1.

As is clear from Table 1, Comparative Examples 1-1 and Comparative Examples were used as solar cell back surface protective films provided with a first resin layer formed using a first thermoplastic resin composition not containing a silane coupling agent. 1-2 had low peel strengths of 12N and 15N, respectively, in adhesion to a film made of an ethylene / vinyl acetate copolymer, and the adhesiveness was not sufficient.
On the other hand, Examples 1-1 to 1-4, which are back surface protective films for solar cells including a first resin layer formed using a first thermoplastic resin composition containing a silane coupling agent, have a peel strength. It was as high as 67 to 82 N, and was excellent in adhesiveness.

4). Manufacture and evaluation of back surface protection film for solar cells (2)
Examples 1-5 to 1-6 and Comparative Examples 1-3 to 1-4
Using the raw material composition for forming the first resin layer, the second resin layer, and the third resin layer shown in Table 2, a back surface protective film for a laminated solar cell was formed in the same manner as in Example 1-1. Obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 2.

As is clear from Table 2, Comparative Examples 1-3 and Comparative Examples were used as solar cell back surface protective films provided with the first resin layer formed using the first thermoplastic resin composition not containing the silane coupling agent. 1-4 had low peel strengths of 17N and 19N, respectively, in adhesion to a film made of an ethylene / vinyl acetate copolymer, and the adhesiveness was not sufficient.
On the other hand, Example 1-5 and Example 1-6 made into the back surface protective film for solar cells provided with the 1st resin layer formed using the 1st thermoplastic resin composition which mix | blended the silane coupling agent peeled. The strength was as high as 64N and 63N, and the adhesiveness was excellent.

5). Manufacture and evaluation of back surface protection film for solar cells (3)
Examples 1-7 to 1-8 and Comparative Example 1-5
Using the raw material composition for forming the first resin layer, the second resin layer, and the third resin layer shown in Table 3, a back surface protective film for a laminated solar cell was formed in the same manner as in Example 1-1. Obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 3. FIG.

As is apparent from Table 3, Comparative Example 1-5, which was a back protective film for solar cells provided with a first resin layer formed using a first thermoplastic resin composition not containing a silane coupling agent, was made of ethylene. -In adhesion | attachment with the film which consists of a vinyl acetate copolymer, peeling strength was as low as 15N and adhesiveness was not enough.
On the other hand, Example 1-7 and Example 1-8 which are back surface protective films for solar cells provided with a first resin layer formed using a first thermoplastic resin composition containing a silane coupling agent were peeled off. The strength was as high as 71N and 77N, and the adhesiveness was excellent.

6). Manufacture and evaluation of back surface protection film for solar cells (4)
Example 2-1
Using a multi-layer film forming machine having a T-die having a die width of 1,400 mm and a lip interval of 1.5 mm and having three extruders with a screw diameter of 65 mm, each extruder is obtained using the first raw material composition. The first thermoplastic resin composition, the second thermoplastic resin composition obtained using the second raw material composition, and the third thermoplastic resin composition obtained using the third raw material composition are supplied. did. Then, each resin composition melted at a temperature of 270 ° C. was discharged from the T die to obtain a three-layer soft film. Thereafter, this three-layer soft film was cooled and solidified with an air knife while being in close contact with a cast roll whose surface temperature was controlled to 95 ° C., to obtain a laminated film having a thickness of 180 μm. The thicknesses of the first resin layer, the second resin layer, and the third resin layer are as shown in Table 4. Thickness gauge "ID-C1112C" (model name) manufactured by Mitutoyo Co., Ltd. is used to cut the film after 1 hour from the start of film production. Then, the thickness was measured at intervals of 10 mm (n = 107), and the average value was obtained. Measurement point values in the range of 20 mm from the edge of the film were removed from the average calculation.
Next, the water vapor barrier layer forming film (R-1) is adhered to the outer surface of the third resin layer in the laminated film using a polyurethane-based adhesive so that the vapor deposition film becomes the outer surface. The back surface protective film for solar cells was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 4.

Example 2-2
Using the first raw material composition, the second raw material composition, the third raw material composition, and the water vapor barrier layer forming film (R-2) shown in Table 4, in the same manner as in Example 2-1, a solar cell A back 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 4.

Example 2-3
Using a multi-layer film forming machine having a T-die having a die width of 1,400 mm and a lip interval of 1.5 mm and having three extruders with a screw diameter of 65 mm, each extruder is obtained using the first raw material composition. The first thermoplastic resin composition, the second thermoplastic resin composition obtained using the second raw material composition, and the third thermoplastic resin composition obtained using the third raw material composition are supplied. did. Then, each resin composition melted at a temperature of 270 ° C. was discharged from the T die to obtain a three-layer soft film. Thereafter, this three-layer soft film was cooled and solidified with an air knife while being in close contact with a cast roll whose surface temperature was controlled to 95 ° C., to obtain a laminated film having a thickness of 180 μm. The thicknesses of the first resin layer, the second resin layer, and the third resin layer are as shown in Table 4. Thickness gauge "ID-C1112C" (model name) manufactured by Mitutoyo Co., Ltd. is used to cut the film after 1 hour from the start of film production. Then, the thickness was measured at intervals of 10 mm (n = 107), and the average value was obtained. Measurement point values in the range of 20 mm from the edge of the film were removed from the average calculation.
Next, the back surface protective layer forming film (P-1) was adhered to the outer surface of the third resin layer in the laminated film using a polyurethane-based adhesive to obtain a back surface protective film for a solar cell. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 4.

Example 2-4
Using the first raw material composition, the second raw material composition, the third raw material composition, and the back surface protective layer forming film (P-2) shown in Table 4, the solar cell was obtained in the same manner as in Example 2-3. A back 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 4.

Example 2-5
Using a multi-layer film forming machine having a T-die having a die width of 1,400 mm and a lip interval of 1.5 mm and having three extruders with a screw diameter of 65 mm, each extruder is obtained using the first raw material composition. The first thermoplastic resin composition, the second thermoplastic resin composition obtained using the second raw material composition, and the third thermoplastic resin composition obtained using the third raw material composition are supplied. did. Then, each resin composition melted at a temperature of 270 ° C. was discharged from the T die to obtain a three-layer soft film. Thereafter, this three-layer soft film was cooled and solidified with an air knife while being in close contact with a cast roll whose surface temperature was controlled to 95 ° C., to obtain a laminated film having a thickness of 180 μm. The thicknesses of the first resin layer, the second resin layer, and the third resin layer are as shown in Table 4. Thickness gauge "ID-C1112C" (model name) manufactured by Mitutoyo Co., Ltd. is used to cut the film after 1 hour from the start of film production. Then, the thickness was measured at intervals of 10 mm (n = 107), and the average value was obtained. Measurement point values in the range of 20 mm from the edge of the film were removed from the average calculation.
Next, the water vapor barrier layer forming film (R-1) is adhered to the outer surface of the third resin layer in the laminated film using a polyurethane-based adhesive so that the vapor deposition film becomes the outer surface. It was. Furthermore, the back surface protective layer forming film (P-1) was adhered to the surface of the vapor deposition film in the water vapor barrier layer using a polyurethane-based adhesive to obtain a back surface protective film for a solar cell. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 4.

  In Examples 2-1 and 2-2, the water vapor barrier property was excellent. Moreover, in Examples 2-3 to 2-5, the scratch resistance was excellent.

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

Example 2-7
Using the first raw material composition, the second raw material composition, the third raw material composition, and the back surface protective layer forming film (P-1) shown in Table 5, the solar cell was obtained in the same manner as in Example 2-1. A back protective film was obtained. And about this back surface protective film for solar cells, various evaluation was performed and the result was written together in Table 5.

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

  In Example 2-6, the water vapor barrier property was excellent. In Examples 2-7 and 2-8, the scratch resistance was excellent.

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

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

Claims (10)

In the back surface protective film for solar cell, comprising the first resin layer, the second resin layer, and the third resin layer sequentially,
The said 1st resin layer is a layer obtained using the thermoplastic resin composition formed by melt-kneading the raw material composition containing a thermoplastic resin and a silane coupling agent, The back surface protection for solar cells characterized by the above-mentioned the film.   2. The solar cell according to claim 1, wherein when light having a wavelength of 400 to 1,400 nm is radiated to the surface of the first resin layer in the solar cell back surface protective film, the reflectance with respect to the light is 50% or more. Back protection film.   The back surface protection film for solar cells according to claim 1 or 2, wherein at least one of the first resin layer, the second resin layer, and the third resin layer contains a white colorant. In the first resin layer, the transmittance for light having a wavelength of 800 to 1,400 nm is 60% or more, the absorptance for light having a wavelength of 400 to 700 nm is 60% or more, and
2. The solar cell according to claim 1, wherein 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 with respect to the light is 50% or more. Back protection film.   The back surface protection film for solar cells according to claim 1 or 4, wherein the first resin layer contains an infrared transmitting colorant, and the second resin layer and / or the third resin layer contains a white colorant. .   The thermoplastic resin constituting the first resin layer, the thermoplastic resin constituting the second resin layer, and the thermoplastic resin constituting the third resin layer contain an aromatic vinyl resin. The back surface protective film for solar cells according to any one of 5.   Furthermore, the back surface protective film for solar cells in any one of Claims 1 thru | or 6 provided with a water vapor | steam barrier layer and / or a back surface protective layer in the said 3rd resin layer side.   The back surface protective film for solar cells according to claim 7, further comprising a third resin layer, a water vapor barrier layer, and a back surface protective layer.   The back surface protective film for solar cells according to any one of claims 1 to 8, which has a thickness of 30 to 1,000 µm.   A solar cell module comprising the solar cell back surface protective film according to claim 1.

Images