JP2013201383A - Backside protective film for solar battery, and solar battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backside protective film for a solar battery which has excellent low heat storage, heat resistance, and flexibility, when receiving sun light on a surface of an infrared ray permeable colorant resin layer, excellent adhesiveness to a member containing ethylene-vinyl acetate copolymer, and excellent durability to a thermal cycle, and high moisture permeability resistance, and a solar battery module.SOLUTION: A backside protective film (1) for a solar battery consists of a stacked body in which an infrared ray permeable colorant resin layer having an infrared ray permeable colorant resin layer (11), a white system resin layer (12) and a metal layer (13) in this order and the metal layers are used as the outermost layer of each surfaces. When light having a wavelength of 400 to 700 nm is radiated to a surface of the infrared ray permeable colorant resin layer, and the backside protective film (1) has an absorbency index to the light is equal to or more than 60%. The infrared ray permeable colorant resin layer (11) contains aromatic vinyl resin and an infrared ray permeable colorant, its thickness is 10 to 300 μm, and the white system resin layer (12) contains aromatic vinyl resin and a white system colorant, and its thickness is 10 to 300 μm.

Description

  The present invention has a dark appearance and absorbs visible light when irradiated with light, but transmits infrared rays to suppress heat storage, and embeds a solar cell element. The present invention relates to a back surface protective film for solar cells and a solar cell module, which are excellent in adhesion to a filler part containing a copolymer composition and the like, heat resistance, flexibility, durability against a thermal cycle and moisture permeability.

  In recent years, solar cells have received more attention as energy supply means in place of petroleum, which is an energy source that forms carbon dioxide, which causes global warming. The demand for solar cells is also increasing, and stable supply and cost reduction of various members constituting solar cell modules included in solar cells have been required. In addition, the demand for improving the power generation efficiency of solar cells has increased.

  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. Thus, the gap between the solar cell elements is filled to form a filler portion, and the back surface (the lower surface of the filler portion) is sealed with a solar cell back surface protective film.

  When a solar cell including a solar cell module is arranged on the roof of a house, it is preferred to be colored in a dark color such as black from the viewpoint of appearance. A solar cell back surface protective film colored in color has come to be used.

  As a film colored in a dark color, for example, a sheet made of a low heat storage thermoplastic resin composition containing a thermoplastic resin and an inorganic pigment having infrared reflection characteristics (see Patent Document 1), a perylene pigment A sheet (see Patent Document 2), which has a black resin layer containing Nb and has a reflectance of 30% or more at a wavelength of 800 to 1,100 nm to prevent near-infrared rays from being reflected (see Patent Document 2). Known is a laminate (see Patent Document 3) in which an infrared transparent colored resin layer is arranged on one side of a high thermoplastic resin layer and a colored resin layer having high light reflectivity is arranged on the other side. Yes.

  Moreover, as a back surface protection sheet for a solar cell module to be used on the back side of a thin film solar cell module manufactured without using crystalline silicon, a first synthetic resin film layer, an aluminum foil layer, a second The aluminum foil layer is composed of 0.1% by mass or more and 6% by mass or less of manganese, more than 0.01% by mass of 0.4% by mass or less of iron, Solar cell module made of an aluminum alloy containing silicon of more than 01% by mass and not more than 0.3% by mass and copper of 0.0001% by mass to 0.01% by mass with the balance containing aluminum and inevitable impurities There is known a back surface protection sheet (see Patent Document 4).

JP 2007-103813 A JP 2007-128943 A JP 2009-119864 A JP 2011-009392 A

  The present invention has a dark-colored appearance and has a low heat storage, heat resistance, flexibility, ethylene / vinyl acetate copolymer when receiving sunlight or the like on the surface of an infrared transparent colored resin layer, An object of the present invention is to provide a solar cell back surface protective film and a solar cell module, which are excellent in adhesiveness, durability against cold cycles and moisture permeability.

The present invention is shown below.
1. An infrared transparent colored resin layer, a white resin layer, and a metal layer are sequentially provided, and the laminate includes the infrared transparent colored resin layer and the metal layer as outermost layers on each surface, and has a wavelength of 400 to 700 nm. When light is radiated to the surface of the infrared transmissive colored resin layer, in the solar cell back surface protective film having an absorption rate of 60% or more, the infrared transmissive colored resin layer includes an aromatic vinyl resin and And a layer having a thickness of 10 to 300 μm, and the white resin layer contains an aromatic vinyl resin and a white colorant, and has a thickness of 10 to 300 μm. A back protective film for a solar cell, which is a 300 μm layer.
2. 2. The solar cell according to 1 above, wherein when light having a wavelength of 800 to 1,400 nm is radiated to the surface of the infrared transparent colored resin layer in the back protective film for solar cells, the reflectance with respect to the light is 50% or more Back surface protection film.
3. The maximum temperature of the glass transition temperature measured according to JIS K 7121 of the aromatic vinyl resin contained in the infrared transmissive colored resin layer is 90 ° C. to 120 ° C., and is contained in the white resin layer. The back surface protective film for solar cells according to 1 or 2 above, wherein the maximum temperature of the glass transition temperature measured according to JIS K 7121 of the aromatic vinyl resin is 90 ° C to 120 ° C.
4). The aromatic vinyl resin contained in the infrared transmissive colored resin layer and the aromatic vinyl resin contained in the white resin layer are both aromatic vinyl in the presence of a rubbery polymer. The back surface protective film for solar cells according to any one of 1 to 3, which is a rubber-reinforced aromatic vinyl resin obtained by polymerizing a vinyl monomer containing a compound.
5. The said white type coloring agent is a back surface protection film for solar cells as described in any one of said 1 thru | or 4 containing the titanium oxide whose average particle diameter is 0.24 micrometer or more.
6). The back protective film for a solar cell according to any one of 1 to 5, wherein the metal layer is made of aluminum having a thickness of 5 to 200 µm.
7). A solar cell module comprising the solar cell back surface protective film according to any one of 1 to 6 above.

According to the solar cell back surface protective film of the present invention, the surface of the infrared transparent colored resin layer is excellent in low heat storage when receiving sunlight or the like, is suppressed in thermal deformation, has excellent heat resistance, and is flexible. Excellent moisture permeability, adhesion to members containing ethylene / vinyl acetate copolymer, and excellent durability against cold cycles. In addition, since the white resin layer is provided, when sunlight or the like enters from the infrared transparent colored resin layer side, the light transmitted through the infrared transparent colored resin layer can be reflected by the white resin layer, When the solar cell module is formed by bonding the surface of the infrared transparent colored resin layer to a solar cell element and a filler part containing an ethylene / vinyl acetate copolymer that embeds the solar cell element and fills the gap between the solar cell element and the reflected light, Thus, the photoelectric conversion efficiency can be improved. Furthermore, since the metal layer is provided, the moisture permeability from the metal layer side is excellent, and deterioration of the solar cell element due to moisture can be suppressed.
When light having a wavelength of 400 to 700 nm is radiated to the surface of the infrared transparent colored resin layer in the back protective film for solar cells, the absorption rate for the light is 60% or more. When a solar cell module excellent in dark appearance can be provided according to the color of the contained infrared transmissive colorant, and the solar cell module provided with the back surface protective film for solar cells is disposed on the roof of a house, etc. In addition, excellent appearance and design can be obtained.
When light having a wavelength of 800 to 1,400 nm is radiated to the surface of the infrared transparent colored resin layer in the back protective film for solar cells, when the reflectance with respect to the light is 50% or more, sunlight is emitted. When it leaks from the gap between adjacent solar cell elements toward the back surface protective film, heat storage in the back surface protective film is suppressed. And reflected light can be made incident on a solar cell element, and power generation efficiency can be improved.
When the maximum temperature of the glass transition temperature measured according to JIS K 7121 of the aromatic vinyl resin of the infrared transparent colored resin layer and the white resin layer is in the range of 90 ° C to 120 ° C. Excellent durability against cooling / heating cycle.
The aromatic vinyl resin contained in the infrared transparent colored resin layer and the white resin layer is obtained by polymerizing a vinyl monomer containing an aromatic vinyl compound in the presence of a rubbery polymer. When the rubber-reinforced aromatic vinyl resin is used, the flexibility of the film is excellent.
When the white colorant contained in the white resin layer contains titanium oxide having an average particle diameter of 0.24 μm or more, the photoelectric conversion efficiency of the solar cell is improved.

  Since the solar cell module of the present invention comprises the solar cell back surface protective film of the present invention, it is suitable for outdoor use exposed to sunlight or wind and rain for a long period of time, and is excellent in power generation efficiency in the solar cell.

It is a schematic sectional drawing which shows an example of the back surface protective film for solar cells. It is a schematic sectional drawing which shows the other example of the back surface protective film for solar cells. It is a schematic sectional drawing which shows an example of a solar cell module. In an Example, it is a top view which shows the form of the back surface protection film for solar cells used for a thermal cycle test. In an Example, it is a schematic sectional drawing which shows the sample structure used for a thermal cycle test.

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

The back surface protective film for solar cells of the present invention has an infrared transparent colored resin layer (hereinafter also referred to as “first layer”), a white resin layer (hereinafter also referred to as “second layer”), and a metal layer (hereinafter also referred to as “second layer”). Hereinafter, also referred to as "third layer"), comprising a laminate comprising an infrared transparent colored resin layer (first layer) and a metal layer (third layer) as the outermost layer on each surface, In the back surface protective film for solar cells, when the light having a wavelength of 400 to 700 nm is radiated to the surface of the infrared transmissive colored resin layer (first layer), the infrared transmissive colored resin layer has an absorption rate of 60% or more for the light. The (first layer) contains an aromatic vinyl resin and an infrared transmitting colorant and has a thickness of 10 to 300 μm. The white resin layer (second layer) is an aromatic vinyl resin. It is a layer containing a resin and a white colorant and having a thickness of 10 to 300 μm.
As described above, since the first layer and the third layer are the outermost layers on the one surface side and the other surface side, respectively, as one aspect, the second layer is between the first layer and the third layer. In other embodiments, the second layer and other layers can be provided. In addition, when each layer is joined with an adhesive or the like, the thickness of the back protective film for solar cells is measured as a thickness including the adhesive layer, but the adhesive layer is not included in the other layers. .

  The schematic cross section of the back surface protective film for solar cells of the present invention is illustrated in FIG. That is, the back surface protective film 1 for solar cells in FIG. 1 is a film (laminated film) made of a laminate including the first layer 11, the second layer 12, and the third layer 13 in order. 2 is a laminated film including another layer 14 between the second layer 12 and the third layer 13.

  In the present invention, the first layer, which is an infrared transmissive colored resin layer, is a layer mainly containing infrared transmissive and preferably absorbing visible light by containing an infrared transmissive colorant. Moreover, since this 1st layer contains the aromatic vinyl-type resin which is a thermoplastic resin, the 1st layer of the back surface protective film for solar cells of this invention, and the ethylene vinyl acetate which embeds a solar cell element It is excellent in adhesiveness with a filler part containing a copolymer composition and the like.

  The constituent material of the first layer will be described as a first thermoplastic resin composition. That is, the first thermoplastic resin composition is a composition containing an aromatic vinyl-based resin and an infrared transmitting colorant, and if necessary, other resins or polymers (hereinafter referred to as “ It may be referred to as “other resin”, which will be described later), and additives.

The aromatic vinyl resin is a resin containing a structural unit derived from an aromatic vinyl compound, and preferably has a maximum glass transition temperature (hereinafter referred to as “Tg”) measured according to JIS K7121. Is an aromatic vinyl resin having a temperature of 90 ° C to 120 ° C.
Examples of the aromatic vinyl resin include a rubber-reinforced aromatic vinyl resin (hereinafter referred to as “resin (A1)” obtained by polymerizing a vinyl monomer containing an aromatic vinyl compound in the presence of a rubber polymer. And a structural unit derived from an aromatic vinyl compound obtained by polymerizing a vinyl monomer containing an aromatic vinyl compound in the absence of a rubbery polymer (co-polymer). ) Polymer (hereinafter referred to as “(co) polymer (A2)”). These may be used alone or in combination. In the present invention, the aromatic vinyl resin preferably contains the resin (A1), and a resin in which the resin (A1) and the (co) polymer (A2) are combined is also a preferred embodiment.
As described above, the first layer may contain other resins. Regardless of the presence or absence of the first layer, when the aromatic vinyl resin contains the resin (A1), the first layer includes The content ratio of the rubber-like polymer to the entire thermoplastic resin contained is preferably 5 to 40% by mass, more preferably 8 to 30% by mass, and still more preferably 10 from the viewpoint of impact resistance and heat resistance of the film. -20% by mass, particularly preferably 12-18% by mass.

  The maximum temperature of Tg of the aromatic vinyl resin is more preferably 92 ° C to 118 ° C. When the maximum temperature of the Tg is in the range of 90 ° C. to 120 ° C., not only is it excellent in adhesiveness with the filler part that embeds the solar cell element, but the solar cell can be used in an environment where there is a great difference in temperature, for example. However, even if it is used over a long period of time, deformation and the like are suppressed, and the durability is excellent. When the said temperature exceeds 120 degreeC, the durability in the heat cycle of the back surface protective film for solar cells will become inadequate. On the other hand, heat resistance is inadequate when the said temperature is less than 90 degreeC. This property relating to the aromatic vinyl-based resin is important in combination with the configurations of the second layer and the third layer. "Durability in cooling cycle" is the result of the cooling cycle test described in [Example]. As a result, the back surface protective film for solar cells does not tear or the length is less than 1 mm. It means that there is.

  As described above, the aromatic vinyl resin is preferably the resin (A1) or a combination of the resin (A1) and the (co) polymer (A2). Each of the resin (A1) and the (co) polymer (A2) may contain one kind or two or more kinds. In this case, all of the resin and the (co) polymer may have respective Tg maximum temperatures in the range of 90 ° C. to 120 ° C., and as a whole aromatic vinyl resin, the maximum temperature of Tg is 90 ° C. As long as it becomes ˜120 ° C., a resin or a polymer having a Tg of less than 90 ° C. or more than 120 ° C. when measured alone may be included.

  The resin (A1) is a vinyl monomer containing an aromatic vinyl compound (hereinafter referred to as “vinyl-based”) in the presence of a rubber polymer (hereinafter referred to as “rubber polymer (a1-1)”). Monomer (a1-2) ") is a rubber-reinforced aromatic vinyl resin obtained by polymerizing, and usually a vinyl monomer (a1-2) containing an aromatic vinyl compound is rubbery. By copolymer resin graft-copolymerized to polymer (a1-1) and ungrafted component not grafted to rubber polymer (a1-1), ie, remaining vinyl monomer (a1-2) (Co) polymers.

  The rubbery polymer (a1-1) used for forming the resin (A1) is not particularly limited as long as it is rubbery at room temperature, and may be either a homopolymer or a copolymer. The rubbery polymer (a1-1) may be a crosslinked polymer or a non-crosslinked polymer.

  The rubbery polymer (a1-1) is not particularly limited, but is conjugated diene rubber, hydrogenated conjugated diene rubber, ethylene / α-olefin copolymer rubber, acrylic rubber, silicone rubber, silicone rubber, Examples include acrylic composite rubber. These can be used alone or in combination of two or more. From the viewpoint of weather resistance, acrylic rubber, silicone rubber, silicone / acrylic composite rubber, ethylene / α-olefin copolymer rubber, hydrogenated conjugated diene rubber, and the like are preferable.

  The shape of the rubber-like polymer (a1-1) is not particularly limited, and may be particulate (spherical or substantially spherical), linear, curved or the like. When it is particulate, the volume average particle diameter is preferably 5 to 2,000 nm, more preferably 10 to 1,800 nm, and still more preferably 50 to 1,500 nm. When the volume average particle diameter is in the above range, the processability of the first thermoplastic resin composition when forming the first layer, the impact resistance of the obtained first layer, and the like are excellent. The volume average particle diameter can be measured by image analysis using an electron micrograph, a laser diffraction method, a light scattering method, or the like.

Examples of the conjugated diene rubber include polybutadiene, butadiene / styrene random copolymer, butadiene / styrene block copolymer, butadiene / acrylonitrile copolymer, and the like. These can be used alone or in combination of two or more.
In the present invention, the conjugated diene rubber preferably has a Tg of −20 ° C. or less from the viewpoints of film flexibility, low-temperature impact properties, and the like.

  The acrylic rubber contains 80% by mass or more of structural units derived from an alkyl acrylate ester having 2 to 8 carbon atoms in the alkyl group based on the total amount of structural units constituting the acrylic rubber (both ) A polymer is 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, 2-acrylate. And ethyl hexyl. These can be used alone or in combination of two or more. Preferred alkyl acrylates are n-butyl acrylate, isobutyl acrylate and 2-ethylhexyl acrylate.

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

In the present invention, the acrylic rubber preferably has a Tg of −10 ° C. or less from the viewpoints of film flexibility, low temperature impact properties, and the like. The acrylic rubber having Tg is usually 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 volume average particle diameter of the acrylic rubber is preferably 5 to 500 nm, more preferably 10 to 450 nm, and still more preferably 20 to 400 nm, from the viewpoints of film flexibility, low temperature impact properties, and the like.

  The acrylic rubber is produced by a known method, but a preferred production method is an emulsion polymerization method.

  The silicone rubber is preferably a rubber contained in a latex in order to facilitate emulsion polymerization, which is a suitable method for producing a rubber-reinforced aromatic vinyl resin. Therefore, the silicone rubber is, for example, a polyorganosiloxane rubber produced by the method described in US Pat. Nos. 2,891,920, 3,294,725, etc. Can do.

  The polyorganosiloxane rubber is obtained by, for example, shear-mixing organosiloxane and water in the presence of a sulfonic acid-based emulsifier such as alkylbenzene sulfonic acid or alkyl sulfonic acid using a homomixer or an ultrasonic mixer. The silicone rubber contained in the latex obtained by the condensation method is preferable. Alkylbenzenesulfonic acid is suitable because it acts as an emulsifier for organosiloxane and also as a polymerization initiator. In this case, it is preferable to use an alkylbenzene sulfonic acid metal salt, an alkyl sulfonic acid metal salt, or the like in combination because it has an effect of stably maintaining the silicone rubber when producing a rubber-reinforced aromatic vinyl resin. The polymer end of the polyorganosiloxane rubber may be sealed with, for example, a hydroxyl group, an alkoxy group, a trimethylsilyl group, a methyldiphenylsilyl group, or the like. Further, if necessary, a graft crossing agent and / or a crosslinking agent may be co-condensed within a range not impairing the target performance of the present invention. By using these, impact resistance can be improved.

The organosiloxane used in the above reaction is, for example, the general formula [R ¹ _m SiO _{(4-m) / 2} ] (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group, and m is 0 to 0. 3 is an integer of 3.). The structure of this compound is linear, branched or cyclic, but is preferably an organosiloxane having a cyclic structure. R ¹ possessed by the organosiloxane, that is, monovalent hydrocarbon groups include alkyl groups such as methyl group, ethyl group, propyl group and butyl group; aryl groups such as phenyl group and tolyl group; vinyl groups and allyl groups An alkenyl group such as: a group in which a part of hydrogen atoms bonded to carbon atoms in these hydrocarbon groups is substituted with a halogen atom, a cyano group, or the like; and at least one hydrogen atom in an alkyl group is substituted with a mercapto group Group and the like.

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

  The graft crossing agent is usually a compound having a carbon-carbon unsaturated bond and an alkoxysilyl group. For example, p-vinylphenylmethyldimethoxysilane, 2- (p-vinylphenyl) ethylmethyldimethoxysilane, 3- (P-Vinylbenzoyloxy) propylmethyldimethoxysilane and the like.

  The amount of the grafting agent used is usually 10 parts by mass or less, preferably 0.2 to 10 parts by mass, more preferably 0. 0 parts by mass, when the total of the organosiloxane, the grafting agent and the crosslinking agent is 100 parts by mass. 5 to 5 parts by mass. If the amount of the graft crossing agent used is too large, the molecular weight of the graft copolymer is lowered, and as a result, sufficient impact resistance may not be obtained. In addition, the oxidative deterioration is more likely to proceed than the double bond of the polyorganosiloxane rubber after grafting, and a resin (A1) having good weather resistance may not be obtained.

  Examples of the crosslinking agent include trifunctional crosslinking agents such as methyltrimethoxysilane, ethyltrimethoxysilane, phenyltrimethoxysilane, and ethyltriethoxysilane, and tetrafunctional crosslinking agents such as tetraethoxysilane. A crosslinkable prepolymer obtained by condensation polymerization of these compounds in advance may be used. These may be used alone or in combination of two or more.

  The amount of the crosslinking agent used is usually 10 parts by mass or less, preferably 5 parts by mass or less, more preferably 0.01 to 5 parts by mass, when the total of the organosiloxane, the grafting agent and the crosslinking agent is 100 parts by mass. Part. When there is too much usage-amount of the said crosslinking agent, the softness | flexibility of the polyorganosiloxane type rubber | gum obtained will be impaired and the flexibility of a film may fall.

  The volume average particle diameter of the silicone rubber is usually 5 to 500 nm, preferably 10 to 400 nm, and more preferably 50 to 400 nm. This volume average particle diameter can be easily controlled by the amount of emulsifier and water used during production, the degree of dispersion when mixed using a homomixer or an ultrasonic mixer, or the method of charging the organosiloxane. If the volume average particle diameter exceeds 500 nm, the appearance may be inferior, such as a decrease in gloss.

  The silicone / acrylic composite rubber is a rubbery polymer containing a polyorganosiloxane rubber and a polyalkyl (meth) acrylate rubber. A preferable silicone-acrylic composite rubber is a composite rubber having a structure in which polyorganosiloxane rubber and polyalkyl (meth) acrylate rubber are intertwined with each other so that they cannot be separated.

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

The polyalkyl (meth) acrylate rubber is preferably methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, ethoxyethoxyethyl acrylate, methoxytripropylene glycol acrylate, 4-hydroxy It is a rubber obtained by (co) polymerizing a monomer containing a (meth) acrylic acid alkyl ester compound such as butyl acrylate, lauryl methacrylate, stearyl methacrylate and the like. These (meth) acrylic acid alkyl ester compounds can be used alone or in combination of two or more.
In addition to the (meth) acrylic acid alkyl ester compounds, the monomers include aromatic vinyl compounds such as styrene, α-methylstyrene and vinyltoluene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; methacrylic acid Various vinyl monomers such as modified silicone and fluorine-containing vinyl compound may be contained in the range of 30% by mass or less.

  The polyalkyl (meth) acrylate-based rubber is preferably a copolymer having two or more Tg because it can impart sufficient flexibility to the film.

  As the silicone-acrylic composite rubber, for example, those manufactured by the methods described in JP-A-4-239010, JP-A-4-100812, and the like can be used.

  The volume average particle diameter of the silicone / acrylic composite rubber is preferably 5 to 500 nm, more preferably 10 to 450 nm, and still more preferably 20 to 400 nm, from the viewpoints of flexibility of the film, low temperature impact property, and the like.

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

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

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

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

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

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. . Examples thereof include styrene, α-methylstyrene, methylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, fluorostyrene, p-tert-butylstyrene, ethylstyrene, vinylnaphthalene, and the like. . These compounds can be used alone or in combination of two or more. Of these, styrene is preferred.
The content ratio of the polymer block A constituting the block copolymer is preferably 0 to 65% by mass, more preferably 10 to 40% by mass with respect to the whole polymer. When there is too much content of the polymer block A, impact resistance may not be enough.

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

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

  Examples of the hydrogenated conjugated diene rubber include hydrogenated polybutadiene, hydrogenated styrene / butadiene rubber, styrene / ethylene butylene / olefin crystal block polymer, olefin crystal / ethylene butylene / olefin crystal block polymer, styrene / ethylene butylene / styrene block polymer. And a hydrogenated product of a butadiene / acrylonitrile copolymer.

  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 of the film is excellent.

  Next, the vinyl monomer (a1-2) used for forming the resin (A1) contains an aromatic vinyl compound. That is, the vinyl monomer (a1-2) may be composed only of an aromatic vinyl compound, an aromatic vinyl compound, and another monomer copolymerizable with these compounds. It may consist of. 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 of introducing a structural unit derived from a maleimide compound into the resin (A1), for example, a method of copolymerizing an unsaturated dicarboxylic anhydride of maleic anhydride and then imidizing may be used. .

Examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, and the like. These 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 (a1-2) preferably contains a vinyl cyanide compound, a maleimide compound, or a (meth) acrylic ester compound.
When the vinyl monomer (a1-2) is composed of an aromatic vinyl compound and a vinyl cyanide compound, the content ratio of these total amounts is molding processability, chemical resistance, hydrolysis resistance, dimensional stability. From the viewpoints of properties, molding appearance, etc., 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 (a1-2). The use ratio of the aromatic vinyl compound and the vinyl cyanide compound was 100% by mass in total from the viewpoint of molding processability, chemical resistance, hydrolysis resistance, dimensional stability, molding appearance, and the like. In such a case, it is preferably 5 to 95% by mass and 5 to 95% by mass, more preferably 50 to 95% by mass and 5 to 50% by mass, still more preferably 60 to 95% by mass and 5 to 40% by mass, respectively.

The preferable aspect of resin (A1) contained in the said 1st layer is as follows.
[1-1] Rubber-reinforced aroma obtained by polymerizing a vinyl monomer (a1-2) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of a rubbery polymer (a1-1). Group vinyl resin.
[1-2] A rubber-reinforced aromatic obtained by polymerizing a vinyl monomer (a1-2) composed of an aromatic vinyl compound and a maleimide compound in the presence of the rubbery polymer (a1-1). Vinyl resin.
[1-3] Obtained by polymerizing a vinyl monomer (a1-2) comprising an aromatic vinyl compound, a vinyl cyanide compound and a maleimide compound in the presence of the rubbery polymer (a1-1). Rubber-reinforced aromatic vinyl resin.
[1-4] Obtained by polymerizing a vinyl monomer (a1-2) composed of an aromatic vinyl compound and a (meth) acrylic acid ester compound in the presence of the rubbery polymer (a1-1). Rubber-reinforced aromatic vinyl resin.
[1-5] Polymerization of a vinyl monomer (a1-2) composed of an aromatic vinyl compound, a vinyl cyanide compound and a (meth) acrylate compound in the presence of the rubbery polymer (a1-1). A rubber-reinforced aromatic vinyl resin obtained as described above.

  The resin (A1) can be produced by polymerizing the vinyl monomer (a1-2) in the presence of the rubbery polymer (a1-1). 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 resin (A1), the rubber polymer (a1-1) and the vinyl monomer (a1-2) are mixed in the reaction system with the rubber polymer (a1-1). ) In the presence of the total amount, the above-mentioned vinyl monomer (a1-2) 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 rubbery polymer (a1-1), the vinyl monomer (a1-2) may be added all at once to initiate polymerization, or divided. Or may be added continuously. At this time, the remainder of the rubber polymer (a1-1) may be added in a batch, divided or continuously during the reaction.

  When the resin (A1) 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 (a1-2) whole quantity.
The polymerization initiator can be added to the reaction system all at once or continuously.

Examples of the chain transfer agent include mercaptans such as octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-hexyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, tert-tetradecyl mercaptan; 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 generally 0.05 to 2.0 mass% with respect to the total amount of the vinyl monomer (a1-2).
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 (a1-2) whole quantity.

Emulsion polymerization can be performed on well-known conditions according to kinds, such as a vinyl-type monomer (a1-2) and a polymerization initiator. The latex obtained by this emulsion polymerization is usually coagulated with a coagulant to make the resin component powdery, and then washed with water and dried to obtain a purified resin. 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 the first thermoplastic resin composition contains two or more kinds of resins (A1), a resin coagulated from one latex (A1-a) and a resin coagulated from another latex (A1- The method of mixing b) and the method of coagulating after preparing a mixture of one latex and another latex can be applied.

  A known method can be applied to the method for producing the resin (A1) by solution polymerization, bulk polymerization, and bulk-suspension polymerization.

  In addition, as said resin (A1), the commercial item which has structures, such as a silicone rubber reinforcement | strengthening aromatic vinyl-type resin and a silicone acrylic resin reinforcement | strengthening aromatic vinyl-type resin, can be used. For example, as the resin (A1) using a silicone / acrylic composite rubber as the rubber polymer (a1-1), for example, Mitsubishi Rayon, which is a commercial product obtained by the method described in JP-A-4-239010, can be used. “Metablene SX-006” (trade name) manufactured by the company, and the like.

  The graft ratio of the resin (A1) is preferably 20 to 170%, more preferably 30 to 170%, and still more preferably 40 to 150%. If this graft ratio is too low, the flexibility of the film may not be sufficient. On the other hand, if the graft ratio is too high, the viscosity of the resin (A1) tends to increase, and it may be difficult to reduce the thickness of the first layer.

The graft ratio can be determined by the following formula.
Graft rate (%) = {(S−T) / T} × 100
In the above formula, 1 g of resin (A1) is added to 20 ml of acetone and shaken with a shaker for 2 hours under a temperature condition of 25 ° C. Then, a centrifuge ( Rotational speed: 23,000 rpm) for 60 minutes, the mass (g) of the insoluble matter obtained by separating the insoluble matter and the soluble matter, and T is a rubbery substance contained in 1 gram of the resin (A1) It is the mass (g) of the polymer (a1-1). The mass of the rubber-like polymer (a1-1) can be obtained by a method of calculating from a polymerization prescription and a polymerization conversion rate, a method of obtaining from an infrared absorption spectrum (IR), and the like.

  The graft ratio can be easily adjusted by adjusting the kind and amount of the polymerization initiator, chain transfer agent, emulsifier, solvent, etc. used in producing the resin (A1), and further the polymerization time, polymerization temperature, etc. Can be controlled.

The (co) polymer (A2) that can be used in combination with the resin (A1) includes a structural unit derived from an aromatic vinyl compound (hereinafter referred to as “structural unit (sa-1)”). A polymer, preferably a copolymer containing a structural unit (sa-1) and a structural unit derived from a vinyl cyanide compound (hereinafter referred to as “structural unit (sa-2)”).
The preferred (co) polymer (A2) may be composed only of the structural units (sa-1) and (sa-2), or the structural unit (sa-1), the aromatic vinyl compound and cyanide. It may consist of a structural unit derived from another monomer copolymerizable with the vinyl compound (hereinafter referred to as “structural unit (sa-3)”), or may be a structural unit (sa-1). , (Sa-2) and (sa-3). Other monomers include (meth) acrylic acid ester compounds, maleimide compounds, unsaturated acid anhydrides, carboxyl group-containing unsaturated compounds, hydroxyl group-containing unsaturated compounds, epoxy group-containing unsaturated compounds, oxazoline group-containing And unsaturated compounds. The compound illustrated in the said vinyl-type monomer (a1-2) is applied to said each compound. The structural unit (sa-3) may be a structural unit derived from one type of monomer, or may be two or more types of structural units derived from two or more types of monomers. The structural unit (sa-3) is preferably a structural unit derived from a maleimide compound. In the case where the (co) polymer (A2) includes a structural unit (sa-3) and the structural unit (sa-3) is a structural unit derived from a maleimide compound, Heat resistance can be imparted.

The content ratio of the structural unit (sa-1) contained in the (co) polymer (A2) is preferably 30 to 100% by mass, more preferably 100% by mass when the total of all the structural units is 100% by mass. It is 40-100 mass%.
When the (co) polymer (A2) includes the structural units (sa-1) and (sa-2), the content ratio of the total amount of the structural units (sa-1) and (sa-2) is all When the total of the structural units is 100% by mass, it is preferably 40 to 100% by mass, more preferably 50 to 100% by mass.

Preferred embodiments of the (co) polymer (A2) contained in the first layer are as follows.
[1-6] A copolymer comprising structural units (sa-1) and (sa-2).
[1-7] A copolymer comprising a structural unit (sa-1) and a structural unit derived from a maleimide compound (hereinafter referred to as “structural unit (sa-3m)”).
[1-8] A copolymer comprising structural units (sa-1), (sa-2), and (sa-3m).

When the (co) polymer (A2) is the above embodiment [1-6], the content ratio of the structural units (sa-1) and (sa-2) is determined by molding processability, chemical resistance, and hydrolysis resistance. From the viewpoints of properties, dimensional stability, molded 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 It is 5-60 mass%, More preferably, it is 50-90 mass% and 10-50 mass%.
Examples of the copolymer of the above embodiment [1-6] include a styrene / acrylonitrile copolymer, an α-methylstyrene / acrylonitrile copolymer, and a styrene / α-methylstyrene / acrylonitrile copolymer.

When the (co) polymer (A2) is the above embodiment [1-7], the content ratios of the structural units (sa-1) and (sa-3m) are molding processability, heat resistance, chemical resistance, From the viewpoint of hydrolysis resistance, dimensional stability, flexibility, etc., when these totals are taken as 100% by mass, preferably 70-99.5% by mass and 0.5-30% by mass, respectively, more preferably Is 80 to 99 mass% and 1 to 20 mass%, more preferably 85 to 98 mass% and 2 to 15 mass%.
Examples of the copolymer of the above embodiment [1-7] include a styrene / N-phenylmaleimide copolymer.

When the (co) polymer (A2) is the above embodiment [1-8], the content ratio of the structural units (sa-1), (sa-2), and (sa-3m) is determined by molding processability and heat resistance. From the viewpoints of properties, chemical resistance, hydrolysis resistance, dimensional stability, flexibility, etc., when these totals are 100% by mass, preferably 10 to 90% by mass and 9.5 to 70% by mass, respectively. % And 0.5-30% by weight, more preferably 20-85% by weight, 14-60% by weight and 1-20% by weight, more preferably 30-80% by weight, 18-50% by weight and 2-15% by weight. %.
Examples of the copolymer of the above embodiment [1-8] include styrene / acrylonitrile / N-phenylmaleimide copolymer.

  Examples of the (co) polymer (A2) include styrene / acrylonitrile / methyl methacrylate copolymer, styrene / N-phenylmaleimide / methyl methacrylate copolymer, styrene / acrylonitrile / N-phenylmaleimide / methyl methacrylate copolymer. A polymer or the like can also be used.

  The (co) polymer (A2) is a vinyl monomer containing an aromatic vinyl compound in the presence or absence of a polymerization initiator (hereinafter referred to as “vinyl monomer (a2)”). Can be produced by polymerization. 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 resin (A1) can be used individually or in combination of 2 or more. The usage-amount of the said polymerization initiator is 0.1-1.5 mass% normally with respect to the said vinylic monomer (a2) whole quantity.
Depending on the polymerization method, chain transfer agents, emulsifiers and the like that can be used during the production of the resin (A1) can be used.

  In the production of the (co) polymer (A2), the polymerization may be started with the total amount of the vinyl monomer (a2) added to the reaction system, and an arbitrarily selected monomer component. The polymerization may be carried out by separately or continuously adding to the reaction system. Furthermore, when using the said polymerization initiator, a polymerization initiator can be added to a reaction system collectively or continuously.

  The intrinsic viscosity [η] (measured in methyl ethyl ketone at 30 ° C.) of the acetone-soluble component of the aromatic vinyl resin using the resin (A1) or (co) polymer (A2) is preferably 0. 0.1 to 2.5 dl / g, more preferably 0.2 to 1.5 dl / g, still more preferably 0.25 to 1.2 dl / g. When the intrinsic viscosity [η] is within the above range, the molding processability of the first thermoplastic resin composition is excellent, and the thickness accuracy of the formed first layer is also excellent.

Here, the intrinsic viscosity [η] can be obtained in the following manner.
When determining the graft ratio in the resin (A1), the acetone-soluble matter recovered after centrifugation is dissolved in methyl ethyl ketone, and five different concentrations are prepared. The intrinsic viscosity [η] is determined by measuring the reduced viscosity of the concentration.
The (co) polymer (A2) is usually soluble in acetone and can be measured in the same manner by dissolving it in methyl ethyl ketone as it is.

  The intrinsic viscosity [η] is the type and amount of a polymerization initiator, a chain transfer agent, an emulsifier, a solvent and the like used for producing the resin (A1) and the (co) polymer (A2), and further polymerization. It can be easily controlled by adjusting time, polymerization temperature and the like.

  The intrinsic viscosity [η] can also be adjusted by appropriately selecting a resin (A1) and a (co) polymer (A2) having different intrinsic viscosities [η].

As described above, the first thermoplastic resin composition may contain other resins.
Other resins include acrylic resins containing structural units derived from (meth) acrylic acid ester compounds; saturated polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate; polyolefin resins; polyvinyl chloride resins; polyvinylidene chloride Resin; Polyvinyl acetate resin; Polycarbonate resin; Fluororesin; Ethylene / vinyl acetate resin and the like. These can be used alone or in combination of two or more.

  When the first thermoplastic resin composition contains another resin, the content thereof is preferably less than 50% by mass, more preferably 40% by mass or less, still more preferably 30%, based on the aromatic vinyl resin. It is below mass%. When the content ratio of the other resin is too high, the effect of using the aromatic vinyl resin according to the present invention is reduced.

When the aromatic vinyl-based resin contains the resin (A1) and further contains another resin regardless of the presence or absence of the (co) polymer (A2), the first thermoplastic resin The content of the resin components in the composition is such that the content of the rubbery polymer (a1-1) derived from the resin (A1) is preferably 5 to 40% by mass, more preferably 8 to 30% by mass, More preferably, it is adjusted to 10 to 20% by mass, particularly preferably 12 to 18% by mass.
When the content rate of the rubber-like polymer (a1-1) contained in the said 1st thermoplastic resin composition exceeds 40 mass%, heat resistance may not be enough. On the other hand, if the content is less than 5% by mass, the impact resistance may not be sufficient.

  The first thermoplastic resin composition contains an infrared transmitting colorant. This infrared transmissive colorant is a colorant having the property of absorbing visible light and transmitting infrared light. This infrared transmissive colorant usually has a color other than white, and is preferably a dark color system such as black, brown, dark blue, or dark green.

〔式中、Ｒ^２及びＲ^３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^４及びＲ^５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、炭素原子数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^６及びＲ^７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、炭素原子数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 transmitting colorant include perylene pigments. As the perylene pigment, compounds represented by the following general formulas (I) to (III) can be used.

[Wherein, R ² and R ³ are the same or different from each other, and are a butyl group, a phenylethyl group, a methoxyethyl group, or a 4-methoxyphenylmethyl group. ]

[Wherein, R ⁴ and R ⁵ are the same as or different from each other, and represent a phenylene group, a 3-methoxyphenylene group, a 4-methoxyphenylene group, a 4-ethoxyphenylene group, an alkylphenylene group having 1 to 3 carbon atoms, a hydroxy group, Phenylene 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 Methyl-2,3-pyridinediyl group, 5-methyl-3,4-pyridinediyl group, 4-methoxy-2,3-pyridinediyl group, or a 4-chloro-2,3-pyridinediyl group. ]

[Wherein, R ⁶ and R ⁷ are the same or different from each other, and represent a phenylene group, a 3-methoxyphenylene group, a 4-methoxyphenylene group, a 4-ethoxyphenylene group, an alkylphenylene group having 1 to 3 carbon atoms, a hydroxy group, Phenylene 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 Methyl-2,3-pyridinediyl group, 5-methyl-3,4-pyridinediyl group, 4-methoxy-2,3-pyridinediyl group, or a 4-chloro-2,3-pyridinediyl group. ]

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

  The content ratio of the infrared transmitting colorant in the first thermoplastic resin composition is preferably 10% by mass with respect to the first thermoplastic resin composition from the viewpoints of infrared transmission and visible light absorption. Hereinafter, it is more preferably 0.01 to 6% by mass, and still more preferably 0.05 to 5% by mass.

In the present invention, the first thermoplastic resin composition can contain other colorants depending on the purpose, application, etc., unless the infrared transmittance in the first layer is reduced.
Examples of other colorants include a cyan colorant (blue color material), a magenta colorant (red color material), and a yellow colorant (yellow color material).

For example, it can be set as an article | item provided with the back surface protective film for solar cells variously colored by the following combinations, using a yellow pigment, a blue pigment, etc. as another coloring agent.
[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 60 parts by mass or less, preferably 0.01 to 55 parts by mass with respect to 100 parts by mass of the infrared transmitting colorant.

  As a dark colorant, carbon black that absorbs light having a wavelength in the infrared region is known. When the first layer is received on the surface of the first layer with respect to the back surface protective film for solar cells formed by a composition using carbon black instead of the infrared transmitting colorant, The heat storage in the first layer becomes significant. Therefore, the solar cell module is formed by bonding the surface of the first layer in the solar cell back surface protective film in this embodiment and the filler portion containing the ethylene / vinyl acetate copolymer composition and the like embedding the solar cell element. When solar light leaks to the first layer containing carbon black, the stored back surface protection film for solar cells raises the temperature of the filler part including the solar cell elements, and power generation efficiency is reduced. There is a problem of lowering. Therefore, in the present invention, the first layer is not carbon black that absorbs light having a wavelength in the infrared region, but includes an infrared transmissive colorant. Such problems can be suppressed.

  The said 1st thermoplastic resin composition shall contain an additive according to the objective, a use, etc. This additive includes antioxidants, ultraviolet absorbers, anti-aging agents, plasticizers, fluorescent brighteners, weathering agents, fillers, antistatic agents, flame retardants, antifogging agents, antibacterial agents, antifungal agents, Antifouling agents, tackifiers, silane coupling agents and the like can be mentioned. Specific compounds in these additives and their contents will be described later.

  Since the first layer is an infrared transparent colored resin layer, when light having a wavelength of 800 to 1,400 nm is radiated on the surface of the film composed of the single layer, the absorptance is preferably 10% or less. More preferably, it has a performance of 8% or less.

  The thickness of the first layer is 10 to 300 μm, preferably 15 to 250 μm, and more preferably 20 to 200 μm, from the viewpoint of the strength and flexibility of the back protective film for solar cells of the present invention.

  In this invention, the 2nd layer which is a white resin layer is a layer which reflects the infrared rays and visible rays which mainly permeate | transmitted the said 1st layer by containing a white colorant. In addition, since the second layer contains an aromatic vinyl-based resin that is a thermoplastic resin, the flexibility balance of the back surface protective film for solar cells of the present invention is highly maintained, and excellent hydrolysis resistance Dimensional stability and impact resistance can be obtained.

  The composition which comprises the said 2nd layer is demonstrated as a 2nd thermoplastic resin composition. That is, the second thermoplastic resin composition is a composition containing an aromatic vinyl resin and a white colorant, and if necessary, other resins and additives similar to those in the first layer. Etc. may be contained.

The aromatic vinyl resin is a resin containing a structural unit derived from an aromatic vinyl compound, and preferably has a maximum glass transition temperature (hereinafter referred to as “Tg”) measured according to JIS K7121. Is an aromatic vinyl resin having a temperature of 90 ° C to 120 ° C.
As the aromatic vinyl resin, a rubber-reinforced aromatic vinyl resin (resin (A1)) obtained by polymerizing a vinyl monomer containing an aromatic vinyl compound in the presence of a rubbery polymer, In addition, a (co) polymer ((co-polymer) containing a structural unit derived from an aromatic vinyl compound obtained by polymerizing a vinyl monomer containing an aromatic vinyl compound in the absence of a rubbery polymer. ) Polymer (A2)). These may be used alone or in combination. In the present invention, the aromatic vinyl resin preferably contains the resin (A1), and a resin in which the resin (A1) and the (co) polymer (A2) are combined is also a preferred embodiment. The aromatic vinyl resin contained in the second layer is an aromatic vinyl resin contained in the first layer (resin (A1) or a combination of resin (A1) and (co) polymer (A2)). May be the same as or different from each other, and the description (configuration and manufacturing method) is applied.
As described above, the second layer may contain other resins. Regardless of the presence or absence of the second layer, when the aromatic vinyl resin contains the resin (A1), the second layer contains The content ratio of the rubber-like polymer to the entire thermoplastic resin contained is preferably 5 to 40% by mass, more preferably 8 to 30% by mass, and still more preferably 10 from the viewpoint of impact resistance and heat resistance of the film. -20% by mass, particularly preferably 12-18% by mass.

Preferred modes of the resin (A1) contained in the second layer are as follows.
[2-1] Rubber-reinforced aroma obtained by polymerizing a vinyl monomer (a1-2) comprising an aromatic vinyl compound and a vinyl cyanide compound in the presence of a rubbery polymer (a1-1). Group vinyl resin.
[2-2] Rubber-reinforced aromatic obtained by polymerizing a vinyl monomer (a1-2) composed of an aromatic vinyl compound and a maleimide compound in the presence of a rubbery polymer (a1-1) Vinyl resin.
[2-3] Obtained by polymerizing a vinyl monomer (a1-2) composed of an aromatic vinyl compound, a vinyl cyanide compound and a maleimide compound in the presence of the rubbery polymer (a1-1). Rubber-reinforced aromatic vinyl resin.
[2-4] Obtained by polymerizing a vinyl monomer (a1-2) composed of an aromatic vinyl compound and a (meth) acrylic acid ester compound in the presence of the rubbery polymer (a1-1). Rubber-reinforced aromatic vinyl resin.
[2-5] Polymerizing a vinyl monomer (a1-2) composed of an aromatic vinyl compound, a vinyl cyanide compound and a (meth) acrylic acid ester compound in the presence of the rubbery polymer (a1-1). A rubber-reinforced aromatic vinyl resin obtained as described above.

Moreover, the preferable aspect of the (co) polymer (A2) contained in the said 2nd layer is as follows.
[2-6] A copolymer comprising structural units (sa-1) and (sa-2).
[2-7] A copolymer comprising a structural unit (sa-1) and a structural unit (sa-3m) derived from a maleimide compound.
[2-8] A copolymer comprising structural units (sa-1), (sa-2) and (sa-3m).

  When the second thermoplastic resin composition contains another resin, the content thereof is preferably less than 50% by mass, more preferably 40% by mass or less, and still more preferably 30% with respect to the aromatic vinyl resin. It is below mass%. When the content ratio of the other resin is too high, the effect of using the aromatic vinyl resin according to the present invention is reduced.

When the aromatic vinyl-based resin contains the resin (A1) and further contains another resin regardless of the presence or absence of the (co) polymer (A2), the second thermoplastic resin The content of the resin components in the composition is such that the content of the rubbery polymer (a1-1) derived from the resin (A1) is preferably 5 to 40% by mass, more preferably 8 to 30% by mass, More preferably, it is adjusted to 10 to 20% by mass, particularly preferably 12 to 18% by mass.
When the content ratio of the rubber-like polymer (a1-1) contained in the second thermoplastic resin composition exceeds 40% by mass, the heat resistance may not be sufficient. On the other hand, if the content is less than 5% by mass, the impact resistance may not be sufficient.

The second thermoplastic resin composition contains a white colorant. 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. These may be used alone or in combination of two or more.

The white colorant preferably contains titanium oxide. The titanium oxide is not particularly limited as long as it is used as a pigment. In the present invention, anatase-type or rutile-type titanium oxide, surface treatment on these titanium oxides (inorganic substances such as aluminum hydroxide, zinc oxide, zirconium oxide, carboxylic acid, polyol, amine, siloxane, silane coupling agent, etc. Can be used. From the viewpoint of thermal stability and weather resistance, rutile type titanium oxide is preferably used.
As a method for producing the rutile type titanium oxide, for example, an aqueous solution of titanium tetrachloride is neutralized and hydrolyzed with an alkaline substance, and the resulting hydrous titanium dioxide is baked, or the hydrous titanium dioxide is made of sodium hydroxide. There is a method in which heat treatment is performed in the presence, and the resulting reaction product is heat-aged in the presence of an acid. Moreover, as a manufacturing method of the said anatase type titanium oxide, there exists a method etc. which hydrolyze a titanyl sulfate.

The average particle diameter of the titanium oxide is preferably 0.24 μm or more, more preferably 0.24 to 1.4 from the viewpoint of reflectivity with respect to light having a wavelength of 800 to 1,400 nm and the photoelectric conversion efficiency of the solar cell thereby. It is 5 μm, more preferably 0.24 to 1.2 μm, particularly preferably 0.24 to 0.80 μm. If the average particle diameter is in the above preferred range, a small particle diameter titanium oxide having a particle diameter of less than 0.24 μm may be used in combination. Preferably it is 50 mass% or less, More preferably, it is 30 mass% or less, More preferably, it is 20 mass% or less, Most preferably, it is 10 mass% or less.
The average particle diameter is a number average particle diameter measured by image analysis using a transmission electron micrograph. For example, an image analysis device such as “Luzex IIIU” manufactured by Nireco Corporation can be used.

  The content ratio of the white colorant in the second thermoplastic resin composition is preferably 1 to 45% by mass with respect to the aromatic vinyl resin from the viewpoint of reflectivity with respect to light having a wavelength of 800 to 1,400 nm. More preferably, it is 3-40 mass%, More preferably, it is 5-30 mass%. When there is too much content of this white type | system | group coloring agent, the flexibility of the back surface protective film for solar cells of this invention may fall.

  Since the second layer is a white resin layer, the L value (brightness) on the surface of the single layer film is preferably 60 or more, more preferably 65 or more, and particularly preferably 70 or more.

  The second thermoplastic resin composition may contain other colorants (for example, a yellow colorant, a blue colorant, etc.) other than the white colorant as long as the L value is not lowered. When using another colorant, the content ratio is usually 10% by mass or less with respect to the second thermoplastic resin composition.

  When the said 2nd thermoplastic resin composition contains an additive, the specific compound and content are mentioned later.

  The thickness of the second layer is 10 to 300 μm, preferably 15 to 250 μm, more preferably 20 to 200 μm. When the said thickness exists in the said range, the flexibility in the back surface protective film for solar cells of this invention can be maintained highly.

Next, the third layer that is a metal layer will be described. This third layer is the outermost layer disposed on the opposite side of the first layer in the back surface protective film for solar cells of the present invention, has moisture resistance, and preferably has resistance to damage due to scratches, stabs, etc. It is a layer to give. Moreover, since the 3rd layer which is an outermost layer is not a layer which consists of organic materials but is a metal layer, it is excellent in thermal conductivity, is excellent also in heat dissipation, and the thermal storage in the back surface protective film for solar cells is suppressed. And the fall of the power generation efficiency in a solar cell can be suppressed.
The constituent material of the third layer may be a metal or an alloy. Examples of the metal include aluminum, copper, iron, titanium, tin and the like. Examples of the alloy include aluminum alloy and stainless steel.
As the aluminum alloy, an alloy composed of Al and at least one selected from Fe, Si, Cu, Ni, Cr, Ti, Zr, Zn, Mn, Mg, and Ga is preferable.
In the present invention, pure aluminum (JIS (AA) 1000 series, such as 1N30, 1N70, IN90, etc.), Al—Mn series (JIS (AA) 3000 series, eg, 3003, 3004 etc.), Al—Mg series ( By using JIS (AA) 5000 system), Al-Fe system (JIS (AA) 8000 system, for example, 8021, 8079, etc.), etc., excellent moisture permeation resistance from the third layer side can be obtained, Deterioration of the solar cell element due to moisture can be suppressed.

  Although the thickness of the said 3rd layer is not specifically limited, From a moisture-permeable viewpoint, Preferably it is 5-200 micrometers, More preferably, it is 5-100 micrometers, More preferably, it is 5-50 micrometers, Most preferably, it is 5-35 micrometers.

As described above, the back surface protective film for a solar cell of the present invention may be an embodiment shown in FIG. 1 or an embodiment including another layer 14 shown in FIG.
The other layer is preferably a resin layer, and particularly preferably a resin layer made of a thermoplastic resin composition containing a thermoplastic resin (hereinafter referred to as “fourth thermoplastic resin composition”). Examples of the thermoplastic resin include polyesters such as polyethylene terephthalate and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene; polyvinylidene chloride, polyvinyl chloride, fluororesin, polysulfone, polystyrene, polyamide, polycarbonate, polyacrylonitrile, and polyimide. Can be mentioned. Moreover, the 4th thermoplastic resin composition may contain the same additive etc. in the said 1st layer as needed.

  When the said 4th thermoplastic resin composition contains an additive, the specific compound and content are mentioned later.

  From the viewpoint of not impairing the effects of the present invention, the thickness of the other layer is preferably 30 to 300 μm, more preferably 40 to 200 μm.

The thickness of the back surface protective film for solar cells of the present invention is preferably 30 to 600 μm, more preferably 40 to 500 μm, from the viewpoints of flexibility, shape followability when disposed on other articles, workability, and the like. More preferably, it is 50-400 micrometers.
In addition, between the 1st layer and the 2nd layer in the back surface protection film for solar cells of the present invention, and / or between the 2nd layer and the 3rd layer, in the range which does not impair the effect of the present invention, Other layers such as a decorative layer, a coating layer, and a layer made of a recycled resin produced during production can also be provided.

  Next, additives contained in the first layer (first thermoplastic resin composition), the second layer (second thermoplastic resin composition), and the other layer (fourth thermoplastic resin composition) (Other colorants, antioxidants, ultraviolet absorbers, anti-aging agents, plasticizers, flame retardants) will be described.

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% by mass with respect to the first thermoplastic resin composition, the second thermoplastic resin composition, or the fourth thermoplastic resin composition.

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% by mass with respect to the first thermoplastic resin composition, the second thermoplastic resin composition, or the fourth thermoplastic resin composition.

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% by mass with respect to the first thermoplastic resin composition, the second thermoplastic resin composition, or the fourth thermoplastic resin composition.

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% by mass with respect to the first thermoplastic resin composition, the second thermoplastic resin composition, or the fourth thermoplastic resin composition.

Examples of the flame retardant include organic flame retardants, inorganic flame retardants, and reactive flame retardants. These can be used alone or in combination of two or more.
Organic flame retardants include brominated epoxy compounds, brominated alkyltriazine compounds, brominated bisphenol epoxy resins, brominated bisphenol phenoxy resins, brominated bisphenol polycarbonate resins, brominated polystyrene resins, brominated crosslinked polystyrene resins Halogenated flame retardants such as brominated bisphenol cyanurate resin, brominated polyphenylene ether, decabromodiphenyl oxide, tetrabromobisphenol A and oligomers thereof; trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, toki Hexyl phosphate, tricyclohexyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate Phosphate esters such as phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, dimethyl ethyl phosphate, methyl dibutyl phosphate, ethyl dipropyl phosphate, hydroxyphenyl diphenyl phosphate, compounds modified with these substituents, various condensed types Phosphorus ester compounds, phosphorus flame retardants such as phosphazene derivatives containing phosphorus elements and nitrogen elements; polytetrafluoroethylene, guanidine salts, silicone compounds, phosphazene compounds, and the like. These can be used alone or in combination of two or more.

Examples of the inorganic flame retardant include aluminum hydroxide, antimony oxide, magnesium hydroxide, zinc borate, zirconium compound, molybdenum compound, and zinc stannate. These can be used alone or in combination of two or more.
Reactive flame retardants include tetrabromobisphenol A, dibromophenol glycidyl ether, brominated aromatic triazine, tribromophenol, tetrabromophthalate, tetrachlorophthalic anhydride, dibromoneopentyl glycol, poly (pentabromobenzyl polyacrylate) , Chlorendic acid (hett acid), chlorendic anhydride (hett acid anhydride), brominated phenol glycidyl ether, dibromocresyl glycidyl ether and the like. These can be used alone or in combination of two or more.

The content of the flame retardant is preferably 10% by mass or less with respect to the first thermoplastic resin composition, the second thermoplastic resin composition, or the fourth thermoplastic resin composition.
In addition, when making a thermoplastic resin composition contain a flame retardant, it is preferable to use a flame retardant aid. As this flame retardant aid, antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, antimony tartrate and other antimony compounds, zinc borate, barium metaborate, hydrated alumina, zirconium oxide, Examples include ammonium polyphosphate and tin oxide. These may be used alone or in combination of two or more.

The method for producing the solar cell back surface protective film of the present invention is selected depending on the constituent material of each layer, that is, each thermoplastic resin composition and metal material. In particular, when the solar cell back surface protective film of the embodiment shown in FIG. 1 is manufactured and the third layer (metal layer) is formed, a metal such as aluminum foil (pure aluminum foil) or aluminum alloy foil is used. It is preferable to use a foil. These aluminum foils or aluminum alloy foils may be any of hard materials, semi-hard materials, soft materials, etc., but soft materials (especially at least one heat treatment (preferably 200 ° C. to 500 ° C.) after rolling). Soft materials) are preferred.
Moreover, when manufacturing the back surface protective film for solar cells of the aspect shown in FIG. 2, the composite material by which the metal film was arrange | positioned on the surface of the resin film which forms another layer can be used. This composite material is polyester resin film, polyolefin resin film, polyvinylidene chloride resin film, polyvinyl chloride resin film, fluororesin film, polysulfone resin film, polystyrene resin film, polyamide resin film, polycarbonate resin film, polyacrylonitrile resin film, The surface of a polyimide resin film or the like may have an aluminum layer or an aluminum alloy layer formed thereon.

The method of manufacturing the back surface protective film for solar cell of the aspect shown in FIG. 1 is shown below.
(1-1) After producing a laminated film by a coextrusion method using the first thermoplastic resin composition and the second thermoplastic resin composition, etc., the surface of the second layer in the laminated film and the metal foil A method of manufacturing by bonding by heat fusion, dry lamination or adhesive.
(1-2) A film for a first layer produced by an extrusion method using the first thermoplastic resin composition, and a film for a second layer produced by an extrusion method using the second thermoplastic resin composition, etc. Is manufactured by joining the surface of the second layer in the laminated film and the metal foil by heat fusion, dry lamination, or an adhesive. how to.
(1-3) a first layer film produced by an extrusion method using the first thermoplastic resin composition, and a second layer film produced by an extrusion method using the second thermoplastic resin composition; A method of manufacturing a metal foil by bonding it by heat fusion, dry lamination or adhesive.

The method of manufacturing the back surface protective film for solar cell of the aspect shown in FIG. 2 is shown below.
(2-1) After producing a laminated film by a coextrusion method using the first thermoplastic resin composition, the second thermoplastic resin composition, and the fourth thermoplastic resin composition, the other layers in the laminated film The method of manufacturing by joining the surface and metal foil by heat sealing | fusion or dry lamination, or an adhesive agent.
(2-2) A first layer film manufactured by an extrusion method using the first thermoplastic resin composition, and a second layer film manufactured by an extrusion method using the second thermoplastic resin composition, and the like. The film for other layer produced by the extrusion method using the fourth thermoplastic resin composition or the like is joined by heat fusion, dry lamination or adhesive to produce a laminated film, and then the other film in the laminated film A method in which the surface of a layer and a metal foil are bonded by thermal fusion, dry lamination, or an adhesive.
(2-3) a first layer film produced by an extrusion method using the first thermoplastic resin composition, and a second layer film produced by an extrusion method using the second thermoplastic resin composition The method for manufacturing by bonding the film for other layers manufactured by the extrusion method etc. which used the 4th thermoplastic resin composition, and metal foil by heat sealing | fusion, dry lamination, or an adhesive agent.
(2-4) After producing a laminated film by a coextrusion method using the first thermoplastic resin composition and the second thermoplastic resin composition, etc., the surface of the second layer in the laminated film and the surface of the resin film A method in which the surface of another layer in a composite material (composite material composed of another layer and a metal layer) having a metal film disposed thereon is bonded by thermal fusion, dry lamination, or an adhesive.
(2-5) a first layer film produced by an extrusion method using the first thermoplastic resin composition, and a second layer film produced by an extrusion method using the second thermoplastic resin composition, etc. While the surface of the second layer film and the other layer in the composite material is in surface contact with the composite material (the composite material composed of the other layer and the metal layer) in which the metal film is disposed on the surface of the resin film, A method of manufacturing by bonding by heat fusion, dry lamination or adhesive.

  Examples of the adhesive include polyurethane resin compositions, epoxy resin compositions, acrylic resin compositions, ethylene / vinyl acetate resin compositions, and the like.

  In the present invention, when light having a wavelength of 400 to 700 nm is radiated to the surface of the first layer in the solar cell back surface protective film, the light absorption rate is 60% or more, preferably 70% or more, and more preferably. Is 80% or more. The higher the absorptance, the lower the brightness of the laminated film viewed from the first layer side, and a dark colored laminated film is formed. Thereby, when a transparent member or a semi-transparent member and the surface of the 1st layer are joined and a composite member is produced, it is excellent in the appearance and design nature seen from the transparent member side. For example, when a back surface protective film is used as a back sheet for a solar cell to produce a solar cell module, and then the solar cell is used, the appearance and design of the solar cell disposed on the roof of a house are excellent. “Absorptivity with respect to light having a wavelength of 400 to 700 nm is 60% or more” means that the absorptance of light in the wavelength region from 400 nm to 700 nm is measured every 400 nm or from 700 nm to 20 nm, and each absorptivity is used. It means that the calculated average value is 60% or more, and it does not require that the light absorption rate in the wavelength range is 60% or more.

  Moreover, in this invention, when the light of wavelength 800-1400nm is radiated | emitted to the surface of the 1st layer in the back surface protective film for solar cells, the reflectance with respect to this light is preferably 50 by the effect | action of a 2nd layer. % Or more, more preferably 60% or more, still more preferably 70% or more. The higher the reflectance, the more light having at least the wavelength can be reflected toward the solar cell element. That is, when a back surface protective film is used as a back sheet for a solar cell and a solar cell module is produced, at least light having the above wavelength can be reflected toward the solar cell element, thereby improving the photoelectric conversion efficiency. Can do. And the thermal storage of a back surface protective film and the temperature rise of the solar cell element by this can be suppressed, and the stable operation of a solar cell can be aimed at. “Reflectance for light with a wavelength of 800 to 1,400 nm is 50% or more” means that the reflectance of light in the wavelength range from 800 nm to 1,400 nm is measured every 800 nm or every 1,400 nm to 20 nm. In addition, it 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 wavelength range are 50% or more.

  By providing these preferable performances, in the back surface protective film for solar cells of the present invention, preferably, 60% or more of light having a wavelength of 400 to 700 nm emitted to the surface of the first layer is absorbed, and a wavelength of 800 When light of ˜1,400 nm is transmitted and this light reaches the second layer, at least the second layer can sufficiently reflect this light and suppress the occurrence of thermal deformation due to light. . Moreover, the solar cell formed by using the back surface protective film as a back sheet for a solar cell, and bonding the surface of the first layer and a filling portion made of an ethylene / vinyl acetate copolymer composition embedding the solar cell element. When a module is used, the reflected light can be used for photoelectric conversion to improve power generation efficiency.

Moreover, since the back surface protective film for solar cells of this invention is equipped with a metal layer, it is excellent in moisture permeability resistance, ie, it is excellent in moisture permeability resistance from the 3rd layer side. And when the water vapor transmission rate of the back surface protective film for solar cells is measured under the conditions of a temperature of 40 ° C. and a humidity of 90% RH according to JIS K7129, it is preferably 3 g / (m ² · day) or less, more preferably 1 g / (m ² · day) or less, more preferably 0.5 g / (m ² · day) or less, and particularly preferably 0.1 g / (m ² · day) or less. Because of having the above performance, when a solar cell module is produced using the back surface protective film for solar cells of the present invention, the deterioration of the solar cell element due to the intrusion of water, water vapor, etc., and further the reduction in power generation efficiency It can be suppressed and has excellent durability.

  Since the back surface protective film for solar cells of the present invention has a metal layer in the third layer, it has excellent heat resistance. For example, when left at 135 ° C. for 30 minutes, the dimensional change rate before and after that is preferably + 10−−. It is 10%, more preferably +8 to -8%, still more preferably +5 to -5%.

When using the back surface protection film for solar cells of this invention as a solar cell backsheet, the schematic of a solar cell module provided with the back surface protection film of this invention is shown by 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 part) 27 and the back surface protective film 1 of the present invention may be disposed in this order. In addition, the solar cell module of this invention can also be suitably equipped with various members other than the said component as needed (not shown).

The surface-side transparent protective member 21 is preferably made of a material excellent in moisture permeation resistance, and usually a transparent substrate made of glass, resin or the like is used. In addition, although glass is excellent in transparency and weather resistance, since impact resistance is not sufficient and heavy, when using as a 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 a plurality of solar cell elements by receiving sunlight, for example, a solar cell element on the surface side sealing film (surface side filler part) 23 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) 23 and the back-side sealing film (back-side filler part) 27 (hereinafter collectively referred to as “sealing film”) are usually identical to 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 as one body by a lamination method or the like in which heat pressure 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 polymer content in aromatic vinyl resin The ratio of the total amount of all rubber polymers to the total amount of aromatic vinyl resin was calculated.
1-2. N-Phenylmaleimide unit content in aromatic vinyl resin The ratio of the N-phenylmaleimide unit amount to the total amount of structural units constituting the aromatic vinyl resin was calculated.
1-3. Glass transition temperature (Tg) of thermoplastic resin
According to JIS K 7121, Tg of the thermoplastic resin (see Tables 1 and 2) constituting each layer was measured with a differential scanning calorimeter “DSC2910” (model name) manufactured by TA Instruments. In addition, when several Tg existed in the DSC curve obtained by measurement, the higher Tg was employ | adopted as Tg of a thermoplastic resin.

1-4. Absorptivity (%) for light having a wavelength of 400 to 700 nm
The film forming the first layer or the back surface protective film for solar cells (50 mm × 50 mm, thickness is listed in the table) is used as a measurement sample, and UV-Vis near-infrared spectrophotometer “V-670” (model) manufactured by JASCO Corporation Name), the transmittance and the reflectance were measured. That is, light was emitted to the surface of the first layer of the measurement sample, and the transmittance and reflectance in the wavelength region 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 (%)}

1-5. Reflectance (%) for light of wavelength 800 to 1,400 nm
Using a solar cell back surface protective film (50 mm x 50 mm, thickness shown in the table) as a measurement sample, the reflectance was measured with an ultraviolet-visible near-infrared spectrophotometer "V-670" (model name) manufactured by JASCO Corporation. did. That is, light was emitted to the surface of the first layer of the measurement sample, the reflectance in the wavelength region from 800 nm to 1,400 nm was measured every 20 nm, and the average value thereof was calculated.

1-6. L value The back surface protective film for solar cells (50 mm x 50 mm, thickness is listed in the table) was used as a measurement sample, and the spectrophotometer “TCS-II” (model name) manufactured by Toyo Seiki Seisakusho Co., Ltd. The value was measured.

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「１」：変形があった。 1-7. Heat resistance Back surface protective film for solar cell (thickness is described in the table) was cut to prepare a test piece having a size of 120 mm (MD; resin extrusion direction) × 120 mm (TD; direction orthogonal to MD) . Next, a square mark of 100 mm (MD) × 100 mm (TD) was drawn at the center of the test piece, and left at 135 ° C. for 30 minutes in a thermostatic bath. Then, it cooled, the length in the said marked line was measured, and the dimensional change rate was computed from following formula (11).

Moreover, the shape of the test piece after a process was observed visually, and the following reference | standard determined.
“3”: There was no deformation.
“2”: Very slightly deformed.
“1”: There was a deformation.

1-8. Flexible Back surface protective film for solar cell (thickness is described in the table) was cut to prepare a test piece having a size of 100 mm (MD) × 100 mm (TD). Next, after bending along the symmetry axis in the MD direction, bending was performed along the symmetry axis in the TD direction. The folded test piece was reciprocated twice on each crease at a speed of 5 mm / sec using a manual crimping roll (2,000 g) according to JIS Z0237. Thereafter, the folds were widened to return to the original state, the test piece was visually observed, and judged according to the following criteria. Those in which the folds are not broken are excellent in flexibility.
“3”: The crease was not broken, and the crease did not break even if it was folded or expanded again.
“2”: The crease was not broken, but the crease was broken when folded and expanded again.
“1”: The crease was broken.

1-9. Adhesiveness with EVA film As described above, when the solar cell back surface protective film is used as a member constituting the solar cell module, the film is composed of the surface of the first layer and the solar cell element included in the solar cell module. It is used for adhering to a back surface side sealing film formed by embedding. Since the ethylene / vinyl acetate copolymer composition is widely used as a material for forming the back surface side sealing film, the adhesion between the surface of the first layer in the back surface protective film for solar cells and the following EVA film is obtained. evaluated.
The back surface protective film for solar cells was cut into a strip shape (200 mm × 15 mm, thickness is shown in the table) to obtain two evaluation films. An EVA film (trade name “Ultra Pearl”, 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 positioned between the first layers of 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. Using an autograph precision universal testing machine “AG-X 20kN” (model name) manufactured by Shimadzu Corporation, the evaluation film in the peel strength measurement sample is not adhered to the EVA film under the condition of a tensile speed of 100 mm / min. T-shaped peeling from the part. The peeled state at this time was visually observed and judged according to the following criteria.
“2”: EVA film was broken.
“1”: Peeled at the interface between the EVA film and the evaluation film.

1-10. Photoelectric conversion efficiency improvement rate In a room adjusted to a temperature of 25 ° C. ± 2 ° C. and a humidity of 50 ± 5% RH, a cell is previously used by using Solar Simulator “PEC-11” (model name) manufactured by Pexel Technologies. A glass of 3 mm thickness was placed on the surface of a 1/4 polycrystalline silicon cell for which the photoelectric conversion efficiency of a single unit was measured, a back surface protective film for solar cells was placed on the back surface, and the silicon cell was sandwiched between the glass and EVA was introduced between the films to seal the silicon cell, and a solar cell module was produced. Then, in order to reduce the influence of temperature, the photoelectric conversion efficiency was measured immediately after the light irradiation. The photoelectric conversion efficiency improvement rate was calculated | required using the obtained photoelectric conversion efficiency and the photoelectric conversion efficiency of the cell single-piece | unit.
Photoelectric conversion efficiency improvement rate (%) = {(photoelectric conversion efficiency of module−photoelectric conversion efficiency of single cell) ÷ (photoelectric conversion efficiency of single cell)} × 100

1-11. Cooling cycle test The back protective film for solar cells is cut into a square (230 mm × 230 mm, thickness is listed in the table), and further, a cut (length 100 mm) is formed in the center as shown in FIG. did.
Next, on a 230 mm × 230 mm × 3 mm glass plate, two 230 mm × 230 mm × 400 μm EVA films (trade name “Ultra Pearl”, manufactured by Sanvic Co., Ltd.) and the above-mentioned back surface protective film for solar cells are sequentially added. , Superimposed (see FIG. 5). The back surface protective film for solar cells was disposed such that the surface of the first layer faces the EVA film. Thereafter, this laminate was put in a laminator, and the upper and lower portions were put in a vacuum state and heated at 150 ° C. for 5 minutes. Next, the upper part was returned to the atmospheric pressure and integrated by pressing for 15 minutes. This integrated product was used as a test specimen for evaluation and subjected to a thermal cycle test.
The cooling / heating cycle test was performed using a thermal shock chamber “TSA-101S-W” (model name) manufactured by Espec. Specifically, the test specimen for evaluation was repeatedly exposed (200 times) under high temperature (100 ° C. for 30 minutes) and low temperature (−40 ° C. for 30 minutes) to protect the back surface for solar cells. The state of occurrence of tears from the cuts in the film was visually observed.
“4”: no tearing occurred.
“3”: The length of the tear was less than 1 mm.
“2”: The length of the tear was 1 mm or more.
“1”: tearing occurred on the entire surface of the film.

1-12. Moisture permeation resistance According to JIS K7129B, the water vapor permeation rate was measured with a water vapor permeability measuring device “PERMATRAN W3 / 31” (model name) manufactured by MOCON. The measurement conditions were a temperature of 40 ° C. and a humidity of 90% RH, and the surface on the third layer side was disposed on the water vapor side as the transmission surface.

2. 2. Raw materials for manufacturing a back surface protective film for solar cell 2-1. Silicone / acrylic composite rubber reinforced aromatic vinyl resin (rubber reinforced resin (A1-1))
“Metablene SX-006” (trade name) manufactured by Mitsubishi Rayon Co., Ltd. was used. This is a resin obtained by grafting an acrylonitrile / styrene copolymer onto a silicone / acrylic composite rubber. The content of the silicone / acrylic composite rubber is 50%, the graft ratio is 80%, the intrinsic viscosity [η] of acetone-soluble component (30 ° C. in methyl ethyl ketone) is 0.38 dl / g, and the glass transition temperature (Tg) is 135. ° C.

2-2. Silicone rubber reinforced aromatic vinyl resin (rubber reinforced resin (A1-2))
1.3 parts of p-vinylphenylmethyldimethoxysilane and 98.7 parts of octamethylcyclotetrasiloxane are mixed, and this is put into 300 parts of distilled water in which 2.0 parts of dodecylbenzenesulfonic acid is dissolved, and 3 parts by a homogenizer. The mixture was stirred and dispersed for emulsification. This emulsified dispersion was transferred to a separable flask equipped with a condenser, a nitrogen inlet and a stirrer, and heated at 90 ° C. for 6 hours while stirring. Subsequently, it was kept at 5 ° C. for 24 hours to complete the condensation, and a latex containing a polyorganosiloxane rubber was obtained. The condensation rate was 93%. Thereafter, the latex was neutralized to pH 7 using an aqueous sodium carbonate solution. The obtained polyorganosiloxane rubber had a volume average particle size of 300 nm.
Next, in a 7-liter glass flask equipped with a stirrer, 100 parts of ion exchange water, 1.5 parts of potassium oleate, 0.01 parts of potassium hydroxide, 0.1 part of tert-dodecyl mercaptan, A batch polymerization component consisting of a latex adjusted to pH 7 containing 40 parts of an organosiloxane rubber, 15 parts of styrene and 5 parts of acrylonitrile was added, and the temperature was raised while stirring. When the temperature reaches 45 ° C., the activity comprises 0.1 part of sodium ethylenediaminetetraacetate, 0.003 part of ferrous sulfate, 0.2 part of sodium formaldehyde sulfoxylate dihydrate and 15 parts of ion-exchanged water. Aqueous agent aqueous solution and 0.1 part of diisopropylbenzene hydroperoxide were added and polymerization was carried out for 1 hour.
Thereafter, 50 parts of ion exchange water, 1 part of potassium oleate, 0.02 part of potassium hydroxide, 0.1 part of tert-dodecyl mercaptan, 0.2 part of diisopropylbenzene hydroperoxide, 30 parts of styrene and An incremental polymerization component consisting of 10 parts of acrylonitrile was added continuously over 3 hours to continue the polymerization. After completion of the addition, stirring was further continued. After 1 hour, 0.2 part of 2,2′-methylenebis (4-ethyl-6-tert-butylphenol) was added to complete the polymerization, and a silicone rubber reinforced aromatic vinyl resin (rubber reinforced resin (A1-2) was added. )) Containing latex was obtained. Next, 1.5 parts of sulfuric acid is added to the latex so that the resin component is solidified at 90 ° C., and then the resin component is washed with water, dehydrated and dried to obtain a silicone rubber reinforced aromatic vinyl resin (rubber reinforced resin). (A1-2)) was obtained. Glass transition temperature (Tg) is 108 ° C., polyorganosiloxane rubber content is 40%, graft rate is 84%, and acetone-soluble intrinsic viscosity [η] (in methyl ethyl ketone, 30 ° C.) is 0.60 dl / g.

2-3. Acrylic rubber reinforced aromatic vinyl resin (rubber reinforced resin (A1-3))
The reactor contains an acrylic rubbery polymer (volume average particle size: 100 nm, gel content: 90%) obtained by emulsion polymerization of 99 parts of n-butyl acrylate and 1 part of allyl methacrylate. 50 parts of latex having a solid content concentration of 40% (in terms of solid content) 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 (rubber reinforced resin (A1-3)) was obtained by washing with water and drying. The content of the acrylic rubbery polymer is 50%, the graft ratio is 93%, the intrinsic viscosity [η] (30 ° C. in methyl ethyl ketone) of the acetone-soluble component is 0.30 dl / g, and the glass transition temperature (Tg) is It was 108 ° C.

2-4. Silicone rubber reinforced aromatic vinyl resin (rubber reinforced resin (A1-4))
1.3 parts of p-vinylphenylmethyldimethoxysilane and 98.7 parts of octamethylcyclotetrasiloxane are mixed, and this is put into 300 parts of distilled water in which 2.0 parts of dodecylbenzenesulfonic acid is dissolved, and 3 parts by a homogenizer. The mixture was stirred and dispersed for emulsification. This emulsified dispersion was transferred to a separable flask equipped with a condenser, a nitrogen inlet and a stirrer, and heated at 90 ° C. for 6 hours while stirring. Subsequently, it was kept at 5 ° C. for 24 hours to complete the condensation, and a latex containing a polyorganosiloxane rubber was obtained. The condensation rate was 93%. Thereafter, the latex was neutralized to pH 7 using an aqueous sodium carbonate solution. The obtained polyorganosiloxane rubber had a volume average particle size of 300 nm.
Next, in a 7-liter glass flask equipped with a stirrer, 100 parts of ion exchange water, 1.5 parts of potassium oleate, 0.01 parts of potassium hydroxide, 0.3 part of tert-dodecyl mercaptan, A batch polymerization component consisting of a latex adjusted to pH 7 containing 18 parts of an organosiloxane rubber, 18 parts of styrene and 6 parts of acrylonitrile was added, and the temperature was raised while stirring. When the temperature reaches 45 ° C., the activity comprises 0.1 part of sodium ethylenediaminetetraacetate, 0.003 part of ferrous sulfate, 0.2 part of sodium formaldehyde sulfoxylate dihydrate and 15 parts of ion-exchanged water. Aqueous agent aqueous solution and 0.03 part of diisopropylbenzene hydroperoxide were added and polymerization was carried out for 1.5 hours.
Thereafter, 50 parts of ion-exchanged water, 1 part of potassium oleate, 0.02 part of potassium hydroxide, 0.3 part of tert-dodecyl mercaptan, 0.08 part of diisopropylbenzene hydroperoxide, 45.5 of styrene were added to the above reaction system. An incremental polymerization component consisting of 15.5 parts of acrylonitrile and 15.5 parts of acrylonitrile was continuously added over 3 hours to continue the polymerization. After completion of the addition, stirring was further continued. After 1 hour, 0.2 part of 2,2′-methylenebis (4-ethyl-6-tert-butylphenol) was added to complete the polymerization, and the silicone rubber reinforced aromatic vinyl resin (rubber reinforced resin (A1-4 )) Containing latex was obtained. Next, 1.5 parts of sulfuric acid is added to the latex so that the resin component is solidified at 90 ° C., and then the resin component is washed with water, dehydrated and dried to obtain a silicone rubber reinforced aromatic vinyl resin (rubber reinforced resin). (A1-4)) was obtained. The glass transition temperature (Tg) is 108 ° C., the content of the polyorganosiloxane rubber is 40%, the graft ratio is 40%, and the intrinsic viscosity [η] (30 ° C. in methyl ethyl ketone) of the acetone soluble component is 0.40 dl / g.

2-5. Acrylonitrile / styrene copolymer (A2-1)
AS polymer “SAN-H” (trade name) manufactured by Techno Polymer Co., Ltd. was used. The glass transition temperature (Tg) is 108 ° C.

2-6. Acrylonitrile / styrene / N-phenylmaleimide copolymer (A2-2)
An 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 acrylonitrile units is 9%, the amount of styrene units is 51%, and the Mw in terms of polystyrene by GPC is 120,000. The glass transition temperature (Tg) is 173 ° C.

2-7. Polyethylene terephthalate resin (A3)
Polyethylene terephthalate “Novapex GM700Z” (trade name) manufactured by Mitsubishi Chemical Corporation was used. The glass transition temperature (Tg) is 155 ° C.

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

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

2-10. Carbon black “Carbon black # 45” (trade name) manufactured by Mitsubishi Chemical Corporation was used.

2-11. White colorant (T1) Titanium oxide “Taipaque CR-60-2” (trade name) manufactured by Ishihara Sangyo Co., Ltd. was used. This titanium oxide has a surface treated with Al and an organic substance, and has an average particle diameter of 0.21 μm.
(T2) Titanium oxide “Taipeku CR-58-2” (trade name) manufactured by Ishihara Sangyo Co., Ltd. was used. This titanium oxide has a surface treated with Al and an organic substance, and has an average particle diameter of 0.28 μm.
(T3) Titanium oxide “Taipeke PF-740” (trade name) manufactured by Ishihara Sangyo Co., Ltd. was used. This titanium oxide has a surface treated with Al, Zr, and an organic substance, and has an average particle diameter of 0.25 μm.
(T4) Titanic titanium oxide “JR-1000” (trade name) was used. This titanium oxide has a surface treated with Al and an average particle diameter of 1 μm.

3. Preparation of first thermoplastic resin composition Production Example 1-1
The rubber reinforced resin (A1-1), the acrylonitrile / styrene copolymer (A2-1), the infrared transmitting colorant, and the yellow colorant were mixed at a ratio shown in Table 1 by a Henschel mixer. Thereafter, using a twin-screw extruder “TEX44” (model name) manufactured by Nippon Steel Works, melt-kneading was performed at a barrel temperature of 240 ° C. to obtain a pellet-shaped first thermoplastic resin composition (I-1) ( (See Table 1).

Production Examples 1-2 to 1-6
Except having used each raw material shown in Table 1 in the ratio shown in Table 1, it is the same as that of manufacture example 1-1, and is the 1st pellet-shaped thermoplastic resin composition (I-2)-(I-6). (See Table 1).

Production Example 1-7
Each pellet shown in Table 1 was used in the proportions shown in Table 1, and the pellet-like first thermoplastic resin composition was prepared in the same manner as in Production Example 1-1 except that the barrel temperature in melt kneading was 270 ° C. (I-7) was obtained (see Table 1).

4). Preparation of second thermoplastic resin composition Production Example 2-1
A rubber-reinforced resin (A1-1), an acrylonitrile / styrene copolymer (A2-1), and titanium oxide (T1) having an average particle diameter of 0.21 μm are mixed by a Henschel mixer at the ratio shown in Table 2. did. Then, it melt-kneaded at the barrel temperature of 240 degreeC using the Nippon Steel Works twin screw extruder "TEX44" (model name), and obtained the pellet-shaped 2nd thermoplastic resin composition (II-1) (Table | Table) 2).

Production Examples 2-2 to 2-10
Except having used each raw material shown in Table 2 in the ratio shown in Table 2, it is the same as that of manufacture example 2-1, and is the pellet-shaped 2nd thermoplastic resin composition (II-2)-(II-10). (See Table 2).

5. Example 1 Production and Evaluation of Back Surface Protection Film for Solar Cell
A multilayer film molding machine having two extruders having a die width of 1,400 mm and a lip interval of 1.5 mm and two screw diameters of 65 mm was used. In each extruder, the first thermoplastic resin composition (I- 1) and the second thermoplastic resin composition (II-1) were supplied. And each composition fuse | melted at 240 degreeC was discharged from the T-die, and it was set as the two-layer type thin body. Thereafter, this two-layer thin body was brought into close contact with a cast roll whose surface temperature was controlled at 65 ° C. with an air knife and cooled and solidified to obtain a two-layer film having a thickness of 99 μm. Thickness gauge "ID-C1112C" (model name) 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.
Next, an aluminum foil having a thickness of 10 μm (referred to as “III-1” in Tables 3 to 5) is applied to the surface on the second layer side of the two-layer film using a polyurethane-based adhesive. It was made to adhere and the back surface protection film for solar cells was obtained. And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 3.

Examples 2-17
Using the first thermoplastic resin composition and the second thermoplastic resin composition shown in Table 3 or Table 4 and an aluminum foil, a back protective film for a solar cell was obtained in the same manner as in Example 1. And about these back surface protection films for solar cells, various evaluation was performed and the result was written together in Table 3 and Table 4. FIG.

Example 18
Using the first thermoplastic resin composition and the second thermoplastic resin composition shown in Table 4, a two-layer film having a thickness of 99 μm was obtained in the same manner as in Example 1. Thereafter, the polyethylene terephthalate layer of the composite film in which the aluminum layer of 10 μm thickness is formed on the polyethylene terephthalate film of 75 μm thickness is bonded to the surface on the second layer side of the two-layer type film using a polyurethane-based adhesive. Then, another layer (polyethylene terephthalate layer) and a third layer (aluminum layer) were sequentially formed to obtain a back protective film for solar cells (see FIG. 2). And about this solar cell back surface protective film, various evaluation was performed and the result was written together in Table 4.

Comparative Example 1
Using the first thermoplastic resin composition and the second thermoplastic resin composition shown in Table 5, a two-layer film having a thickness of 99 μm obtained in the same manner as in Example 1, was used as a back protective film for solar cells. It was. And about this back surface protective film for solar cells, various evaluation was performed and the result was written together in Table 5.

Comparative Example 2
Using the first thermoplastic resin composition and the second thermoplastic resin composition shown in Table 5 and the aluminum foil, a back surface protective film for a solar cell was obtained in the same manner as in Example 1. And about these back surface protective films for solar cells, various evaluation was performed and the result was written together in Table 5.

Comparative Example 3
The first thermoplastic resin composition (I-7) was used in a single-layer film molding machine having a T-die having a die width of 1,400 mm and a lip interval of 1.5 mm and equipped with an extruder having a screw diameter of 65 mm. Supplied. And the composition fuse | melted at 240 degreeC was discharged from the T die, and it was set as the thin body. Then, this thin-walled body was brought into surface contact with a cast roll whose surface temperature was controlled to 65 ° C. with an air knife and cooled and solidified to obtain a single-layer film having a thickness of 30 μm. Thickness gauge "ID-C1112C" (model name) 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.
Next, an aluminum foil having a thickness of 10 μm was adhered to the surface of the single-layer film using a polyurethane-based adhesive to form a third layer, thereby obtaining a solar cell back surface protective film. And about this back surface protective film for solar cells, various evaluation was performed and the result was written together in Table 5.

  Comparative Example 1 is an example that does not include a metal layer, and is inferior in moisture permeability. Comparative Example 2 is an example using carbon black, which is a colorant that does not transmit infrared rays, in the first layer, and the photoelectric conversion rate improvement rate is insufficient. Comparative Example 3 is an example in which the first layer does not contain an aromatic vinyl resin and does not include the second layer according to the present invention, and is inferior in adhesiveness.

  In the back surface protective film for solar cells of the present invention, when light is radiated to the first layer, infrared rays are easily transmitted, so that the first layer is excellent in low heat storage, and the light transmitted through the first layer Excellent reflectivity in two layers. In a high temperature environment, thermal deformation due to light reception or the like is suppressed, and heat resistance is excellent, and design properties and moisture permeability resistance can be maintained over a long period of time. Moreover, it is excellent in the adhesiveness between the surface of the first layer and a member containing an ethylene / vinyl acetate copolymer, and the workability and the handleability thereof are good. Therefore, an article provided with a support portion on the third layer side, a member containing an ethylene / vinyl acetate copolymer, etc., such as an article joined to the first layer side surface, is exposed to, for example, sunlight or wind and rain for a long time. It is suitable for applications requiring shape stability over a long period of time. Especially, it is useful as a structural member of the solar cell module which comprises the solar cell arrange | positioned on roofs, such as a house and a building, ie, a solar cell backsheet. Since this back surface protective film is excellent in flexibility, it is not dependent on the shape of the solar cell module, that is, it is arranged according to the surface shape of the filler portion filling the gaps of the solar cell elements included in the solar cell module. It is suitable for protection of solar cell elements.

1: Back surface protective film for solar cell 11: First layer (infrared transparent colored resin layer)
12: Second layer (white resin layer)
13: Third layer (metal layer)
14: Other layer (resin layer)
2: Solar cell module 21: Front side transparent protective member 23: Front side sealing film 25: Solar cell element 27: Back side sealing film 3: Cut 5: EVA film 7: Glass plate

Claims (7)

An infrared transparent colored resin layer, a white resin layer, and a metal layer are sequentially provided, and the laminate includes the infrared transparent colored resin layer and the metal layer as outermost layers on each surface. In the case where the light is emitted to the surface of the infrared transparent colored resin layer, the solar cell back surface protective film having an absorption rate of 60% or more for the light,
The infrared transparent colored resin layer contains an aromatic vinyl resin and an infrared transparent colorant and has a thickness of 10 to 300 μm.
The said white resin layer contains an aromatic vinyl resin and a white colorant, and is a layer of thickness 10-300 micrometers, The back surface protective film for solar cells characterized by the above-mentioned.   2. The sun according to claim 1, wherein when light having a wavelength of 800 to 1,400 nm is radiated to the surface of the infrared transparent colored resin layer in the back surface protective film for solar cells, the reflectance with respect to the light is 50% or more. Battery back surface protection film. The maximum temperature of the glass transition temperature measured according to JIS K 7121 of the aromatic vinyl resin contained in the infrared transparent colored resin layer is 90 ° C to 120 ° C,
The back surface for solar cells according to claim 1 or 2, wherein the maximum temperature of the glass transition temperature of the aromatic vinyl resin contained in the white resin layer measured according to JIS K 7121 is 90 ° C to 120 ° C. Protective film.   The aromatic vinyl resin contained in the infrared transmissive colored resin layer and the aromatic vinyl resin contained in the white resin layer are both aromatic vinyl in the presence of a rubbery polymer. The back surface protective film for a solar cell according to any one of claims 1 to 3, which is a rubber-reinforced aromatic vinyl resin obtained by polymerizing a vinyl monomer containing a compound.   The solar cell back surface protective film according to any one of claims 1 to 4, wherein the white colorant includes titanium oxide having an average particle size of 0.24 µm or more.   The back protective film for solar cells according to any one of claims 1 to 5, wherein the metal layer is made of aluminum having a thickness of 5 to 200 µm.   A solar cell module comprising the solar cell back surface protective film according to any one of claims 1 to 6.

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