JP2014095066A - Back sheet for solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive for a solar cell module which does not undergo blocking easily, has excellent initial adhesion to a base material, and has an excellent adhesive property to a filler not only in an environment in which it is actually used as a solar cell but also even when an accelerated test (a wet heat test) in a high temperature-high humidity atmosphere investigated when a solar cell module is evaluated; a back sheet for a solar cell module; solar cell module; and a solar cell.SOLUTION: Provided is an adhesive for a solar cell module used for pasting a back sheet used for a solar cell module with a filler, comprising a thermoplastic resin, a curing agent and plate-like particles. Also provided are a back sheet for a solar cell module using the adhesive; a solar cell module; and a solar cell.

Description

  The present invention relates to a back sheet for a solar cell module. More specifically, the present invention relates to a solar cell module adhesive used for bonding a solar cell module backsheet and a filler, and a solar cell on which an adhesive layer made of the solar cell module adhesive is formed. The present invention relates to a module backsheet, a solar cell module having the solar cell module backsheet, and a solar cell having the solar cell module.

  Since the solar cell module is mainly used outdoors, its material and structure are required to have durability and weather resistance. In particular, the solar cell module backsheet is required to have a weather resistance and a low water vapor transmission rate, that is, excellent moisture barrier properties. Furthermore, since it is necessary to maintain the performance of a solar cell for about 20 years, in order to evaluate the durability of the solar cell, for example, an accelerated test in a high-temperature and high-humidity atmosphere at 85 ° C. and a relative humidity of 85%. (Moisture and heat resistance test) has been conducted.

  Conventionally, an ethylene-vinyl acetate copolymer (hereinafter referred to as EVA) has been used as a filler for a solar cell module backsheet because it has weather resistance and flame retardancy (for example, Patent Document 1 and 2). Moreover, since it is excellent in electrical insulation as a back seat | sheet for solar cell modules, polyester films, such as a polyethylene terephthalate, are used (for example, refer patent documents 3-6). However, the polyester film used in the solar cell module backsheet and EVA used as a filler are excellent in adhesiveness during the production of solar cells, but the adhesiveness decreases with time. There are drawbacks.

  Moreover, the stain | pollution | contamination by the coloring resin layer currently formed in the sheet | seat for back surface protection for solar cells adhering to the fluororesin sheet | seat used when laminating a solar cell module is made not conspicuous on the surface of a fluororesin sheet | seat. For this reason, a solar cell back surface protection sheet having a multilayer colored layer in which a transparent layer and a colored layer are laminated from the side that adheres to the sealing material has been proposed (see, for example, Patent Document 7). However, this solar cell back surface protection sheet originally requires a transparent layer that may not be used, and the transparent layer remains attached to the fluororesin sheet.

Japanese National Patent Publication No. 08-500214 Japanese translation of PCT publication No. 2002-520820 JP 2001-1111073 A Japanese Patent Laid-Open No. 2002-100788 JP 2002-134771 A JP 2002-026354 A JP 2011-222947 A

  The present invention has been made in view of the above-described prior art, has a small blocking property, excellent initial adhesion to a substrate, and evaluates not only an environment actually used as a solar cell but also a solar cell module. Even when an accelerated test (humidity heat resistance test) in a high-temperature and high-humidity atmosphere that has been studied is performed, the adhesive for solar cell modules excellent in adhesiveness to fillers used in solar cells, An object is to provide a back sheet for a solar cell module in which an adhesive layer made of an adhesive for a solar cell module is formed, a solar cell module having the back sheet for the solar cell module, and a solar cell having the solar cell module. To do.

The present invention
(1) Adhesive for solar cell module, which is an adhesive used for bonding a back sheet and a filler used for a solar cell module, and contains a thermoplastic resin, a curing agent and plate-like particles. Agent,
(2) The adhesive for solar cell modules according to (1), wherein the curing agent is at least one selected from the group consisting of (block) polyisocyanate compounds, epoxy resins, and oxazoline group-containing resins,
(3) It is a back sheet used for a solar cell module, and is bonded to the surface to be bonded to the filler constituting the solar cell module, the adhesive comprising the solar cell module adhesive according to (1) or (2). A back sheet for a solar cell module, wherein an agent layer is formed,
(4) A solar cell module having the back sheet for a solar cell module according to (3), and (5) a solar cell having the solar cell module according to (4). About.

  The adhesive for a solar cell module of the present invention has a small blocking property, excellent initial adhesion to a substrate, and has been examined when evaluating a solar cell module as well as an environment actually used as a solar cell. Even if it is a case where the accelerated test (humidity heat resistance test) is performed in the high-temperature, high-humidity atmosphere, it has the effect of being excellent in the adhesiveness with respect to the filler used for a solar cell.

  The back sheet for the solar cell module of the present invention is formed with an adhesive layer made of the adhesive for the solar cell module. Therefore, the blocking property is small, the initial adhesion to the substrate is excellent, and the solar cell module is actually used as a solar cell. In addition to the environment used for solar cells, the filler used for solar cells, even when an accelerated test (humid heat resistance test) in a high-temperature and high-humidity atmosphere, which has been studied when evaluating solar cell modules There is an effect that it is excellent in adhesiveness.

  Since the solar cell module of the present invention has the back sheet for the solar cell module, the blocking property is small, the initial adhesion to the substrate is excellent, and not only the environment actually used as a solar cell, but also the solar cell. Even when the accelerated test (humidity heat resistance test) in a high-temperature and high-humidity atmosphere, which is being considered when evaluating the module, the effect of being excellent in adhesiveness to the filler used in the solar cell is exhibited.

  Since the solar cell of the present invention has the back sheet for the solar cell module, the blocking property is small, the initial adhesion to the substrate is excellent, and not only the environment actually used as a solar cell, but also the solar cell module. Even when an accelerated test (humidity heat resistance test) in a high-temperature and high-humidity atmosphere, which has been studied in evaluating the above, is effective in adhering to a filler used in a solar cell.

It is a schematic sectional drawing which shows one embodiment of the solar cell module backsheet of this invention. It is a schematic sectional drawing of the back sheet for solar cell modules which interposed the barrier layer as another embodiment of the back sheet for solar cell modules of this invention.

  As described above, the adhesive for a solar cell module of the present invention is an adhesive used for bonding a back sheet and a filler used in a solar cell module, and includes a thermoplastic resin, a curing agent, and plate-like particles. It is characterized by containing.

  Examples of the thermoplastic resin include (meth) acrylic resins; polyolefin resins such as polyethylene, polypropylene, ethylene-propylene copolymer, poly (4-methyl-1-pentene); vinyl chloride, vinylidene chloride, chlorinated vinyl chloride. Resin and other halogenated vinyl resins; polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer and other styrene resins; polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and other polyesters Resins; Polyamide resins such as nylon 6, nylon 66, nylon 610; polyacetal; polycarbonate; polyphenylene oxide; Polyetheretherketone; Polysulfone; Polyethersulfone; Polyoxybenzylene; Polyamideimide; Rubber resins such as ABS resin and ASA resin blended with polybutadiene rubber and acrylic rubber, and the like. However, the present invention is not limited to such examples. These thermoplastic resins may be used alone or in combination of two or more. Among these thermoplastic resins, excellent initial adhesion to the base material, and also in a high-temperature and high-humidity atmosphere studied when evaluating solar cell modules as well as the environment actually used as solar cells. (Meth) acrylic resins are preferred from the viewpoint of obtaining an adhesive for solar cell modules that is excellent in adhesion to fillers used in solar cells, even when an accelerated test (moisture heat resistance test) is performed.

  In the present specification, “(meth) acryl” means “acryl” or “methacryl”, and “(meth) acrylate” means “acrylate” or “methacrylate”.

  As (meth) acrylic resin, (meth) acrylic resin that is generally used for adhesives for solar cell modules can be used, but it has excellent initial adhesion to the substrate and is actually used as a solar cell. Adhesion to fillers used in solar cells, even when the accelerated test (humidity heat resistance test) is performed in a high-temperature and high-humidity atmosphere, which is being considered when evaluating solar cell modules. Ring structure-containing (meth) acrylic polymer having a ring structure containing a hetero atom in the main chain [hereinafter also referred to as ring structure-containing (meth) acrylic polymer] Is preferred.

  The ring structure-containing (meth) acrylic polymer is excellent in the initial adhesion to the substrate, and is not only used in the environment where it is actually used as a solar cell, but also in high temperature and high humidity which is being studied when evaluating solar cell modules. Even when an accelerated test (moisture and heat resistance test) is performed in an atmosphere, an excellent effect of giving an adhesive for solar cell modules excellent in adhesiveness to a filler used in a solar cell is exhibited.

  The ring structure-containing (meth) acrylic polymer is excellent in the initial adhesion to the substrate, and is not only used in the environment where it is actually used as a solar cell, but also in high temperature and high humidity which is being studied when evaluating solar cell modules. From the viewpoint of producing an adhesive for solar cell modules excellent in adhesion to fillers used in solar cells, even when an accelerated test (humid heat resistance test) is performed in the atmosphere, the formula (I):

(Wherein R ¹ is a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms which may have a halogen atom, a glycidyl group or a tetrahydrofurfuryl group, R ² is a methylene group, R ³ is a direct bond or methylene. Group, R ⁴ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a carboxyl group, an ester group or a cyano group, R ⁵ is a direct bond or a methylene group, and X and Y are each independently 1 to 1 carbon atom. Methylene group optionally having 4 alkyl groups, imino group, carbonyl group, oxygen atom or sulfur atom, Z is a direct bond, methylene group optionally having 1 to 4 carbon atoms, imino A group, a carbonyl group, an oxygen atom or a sulfur atom, at least one of X, Y and Z is an oxygen atom, a sulfur atom or an imino group which are not adjacent to each other)
A (meth) acrylic polymer having a ring structure-containing unit represented by formula (Ia):

(Wherein R ¹ represents a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms)
It is more preferable that it is a (meth) acrylic-type polymer which has a ring structure containing unit represented by these.

In the formula (I) and the formula (Ia), R ¹ is a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms which may have a halogen atom, a glycidyl group or a tetrahydrofurfuryl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Of these halogen atoms, a fluorine atom and a chlorine atom are preferable. Since the number of halogen atoms contained in the hydrocarbon group varies depending on the number of carbon atoms in the hydrocarbon group and cannot be determined unconditionally, the halogen atom in the hydrocarbon group is within the range not hindering the object of the present invention. May be included. Examples of the hydrocarbon group having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-ethylhexyl, heptyl, and octyl. A linear or branched alkyl group having 1 to 20 carbon atoms such as a group, nonyl group, decyl group, undecyl group, dodecyl group, pentadecyl group, octadecyl group; cyclopropyl group, cyclopentyl group, cyclohexyl group, methylcyclohexyl group An alicyclic hydrocarbon group having 3 to 20 carbon atoms such as cyclododecyl group; a polycyclic hydrocarbon group having 7 to 20 carbon atoms such as n-bornyl group and isobornyl group; phenyl group, tolyl group, xylyl group, C6-C12 aryl group such as naphthyl group; C7-C12 such as benzyl group, phenylethyl group, methylbenzyl group And aralkyl groups. Among R ¹ , an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 4 to 20 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyl group, and a tetrahydrofurfuryl group are preferable. More preferably, a branched chain alkyl group having 20 to 20 carbon atoms, an alicyclic hydrocarbon group having 6 to 20 carbon atoms, a glycidyl group and a tetrahydrofurfuryl group, and an alkyl group having 1 to 20 carbon atoms, a glycidyl group and a tetrahydrofurfuryl group. Is more preferable, an alkyl group having 1 to 6 carbon atoms is still more preferable, and a methyl group or an ethyl group is particularly preferable.

In the formula (I), R ² is a methylene group. R ³ is a direct bond or a methylene group. R ⁴ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a carboxyl group, an ester group or a cyano group. Of the alkyl groups having 1 to 4 carbon atoms, a methyl group is preferable. Examples of the ester group include a group represented by the formula: —COOR ⁶ (wherein R ⁶ represents an alkyl group having 1 to 4 carbon atoms). R ⁵ is a direct bond or a methylene group. X and Y are each independently a methylene group, imino group, carbonyl group, oxygen atom or sulfur atom which may have an alkyl group having 1 to 4 carbon atoms. Z is a direct bond, a methylene group optionally having an alkyl group having 1 to 4 carbon atoms, an imino group, a carbonyl group, an oxygen atom or a sulfur atom. At least one of X, Y and Z is an oxygen atom, sulfur atom or imino group which is not adjacent to each other. Examples of the imino group include a —NR ⁷ — group (wherein R ⁷ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). The “oxygen atom, sulfur atom or imino group not adjacent to each other” is a hetero atom adjacent to each other such as —O—O— or —O—NR ⁷ — (wherein R ⁷ is the same as above). Means not fit.

  1,5-diene structure-containing monomer containing a hetero atom and 1,6-diene structure-containing monomer containing a hetero atom as a diene structure-containing monomer giving a ring structure-containing unit represented by the formula (I) At least one diene structure-containing monomer selected from the group consisting of: Among the diene structure-containing monomers that give the ring structure-containing unit represented by the formula (I), preferred monomers include the formula (II):

(Wherein R ¹ , X, Y and Z are the same as above, R ⁸ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a carboxyl group, an ester group or a cyano group)
The diene structure containing monomer represented by these is mentioned. Of the alkyl groups having 1 to 4 carbon atoms, a methyl group is preferable. Examples of the ester group include a group represented by the formula: —COOR ⁶ (wherein R ⁶ is the same as described above).

  Specific examples of the diene structure-containing monomer represented by the formula (II) include the formula (IIa):

(Wherein R ¹ is the same as above)
1,6-diene structure-containing monomer represented by the formula (IIb):

(Wherein R ¹ is the same as above)
1,6-diene structure-containing monomer represented by the formula (IIc):

(Wherein, R ¹ is the same as above, and each R ¹ may be the same or different)
1,6-diene structure-containing monomer represented by the formula (IId):

(Wherein R ¹ and R ⁷ are the same as above)
1,6-diene structure-containing monomer represented by the formula (IIe):

(Wherein R ¹ is the same as above)
1,6-diene structure-containing monomer represented by the formula (IIf):

(Wherein R ¹ and R ⁷ are the same as above)
1,6-diene structure-containing monomer represented by the formula (IIg):

(Wherein R ¹ is the same as above)
1,5-diene structure-containing monomer represented by the formula (IIh):

(Wherein R ¹ is the same as above)
1,5-diene structure-containing monomer represented by the formula (IIi):

(Wherein R ¹ is the same as above)
1,5-diene structure containing monomers represented by these.

  Among the diene structure-containing monomers, the initial adhesiveness to the substrate is excellent, and not only the environment actually used as a solar cell, but also a high temperature and high humidity that is being studied when evaluating solar cell modules. Even when an accelerated test (moisture and heat resistance test) is performed in an atmosphere, from the viewpoint of obtaining an adhesive for a solar cell module excellent in adhesion to a filler used in a solar cell, 1,5 containing a hetero atom -At least one diene structure-containing monomer selected from the group consisting of a diene structure-containing monomer and a 1,6-diene structure-containing monomer containing a hetero atom is preferred, and 1 represented by the formula (IIa) , 6-diene structure-containing monomer, 1,6-diene structure-containing monomer represented by formula (IIb), and 1,6-diene structure-containing monomer represented by formula (IIc) Used for That from the viewpoint of further improving the adhesion to the filler, 1,6 diene structure-containing monomer represented by formula (IIa) is more preferable. These monomers can be prepared, for example, by the method described in JP-A-10-226669.

  Examples of the 1,6-diene structure-containing monomer represented by the formula (IIa) include α-allyloxymethyl acrylic acid, α-allyloxymethyl acrylate methyl, α-allyloxymethyl ethyl acrylate, α- Propyl allyloxymethyl acrylate, butyl α-allyloxymethyl acrylate, tert-butyl α-allyloxymethyl acrylate, cyclohexyl α-allyloxymethyl acrylate, α-allyloxymethyl acrylate dicyclopentadienyl, α -Allyloxymethyl acrylic acid and esters thereof such as isobornyl allyloxymethyl acrylate, adamantyl α-allyloxymethyl acrylate, benzyl α-allyloxymethyl acrylate, and the like are included, but the present invention is limited to such examples only. It is not something. These monomers may be used alone or in combination of two or more. Among these, the initial adhesion to the substrate is excellent, and further, not only the environment actually used as a solar cell, but also an accelerated test in a high-temperature and high-humidity atmosphere that is being considered when evaluating solar cell modules ( From the viewpoint of obtaining an adhesive for solar cell modules having excellent adhesion to fillers used in solar cells, even when a moisture and heat resistance test is conducted, methyl α-allyloxymethyl acrylate, α-allyloxy Preferred are ethyl methyl acrylate, cyclohexyl α-allyloxymethyl acrylate and benzyl α-allyloxymethyl acrylate, more preferably methyl α-allyloxymethyl acrylate.

  Examples of the 1,6-diene structure-containing monomer represented by the formula (IIb) include, for example, α-methallyloxymethyl acrylic acid, α-methallyloxymethyl acrylate methyl, α-methallyloxymethyl acrylate ethyl Α-methallyloxymethyl acrylate, butyl α-methallyloxymethyl acrylate, tert-butyl α-methallyloxymethyl acrylate, cyclohexyl α-methallyloxymethyl acrylate, α-methallyloxymethylacrylic Examples include methallyloxymethyl acrylic acid such as dicyclopentadienyl acid, isobornyl α-methallyloxymethyl acrylate, adamantyl α-methallyloxymethyl acrylate, benzyl α-methallyloxymethyl acrylate, and esters thereof. However, the present invention is limited to only such examples. Not to. These monomers may be used alone or in combination of two or more. Among these, the initial adhesion to the substrate is excellent, and further, not only the environment actually used as a solar cell, but also an accelerated test in a high-temperature and high-humidity atmosphere that is being considered when evaluating solar cell modules ( From the viewpoint of obtaining an adhesive for a solar cell module having excellent adhesion to a filler used in a solar cell even when a wet heat resistance test is performed, methyl α-methallyloxymethyl acrylate, α-meta Ethyl ryloxymethyl acrylate, cyclohexyl α-methallyloxymethyl acrylate and benzyl α-methallyloxymethyl acrylate are preferred, and methyl α-methallyloxymethyl acrylate is more preferred.

  Examples of the 1,6-diene structure-containing monomer represented by the formula (IIc) include bis (α-hydroxymethylacrylic acid) ether, bis (α-hydroxymethylacrylic acid methyl) ether, and bis (α-hydroxy). Methyl acrylate) ether, bis (α-hydroxymethyl propyl acrylate) ether, bis (α-hydroxymethyl butyl acrylate) ether, bis (α-hydroxymethyl acrylate tert-butyl) ether, bis (α-hydroxy) Cyclohexyl methyl acrylate) ether, bis (α-hydroxymethyl acrylate dicyclopentadienyl) ether, bis (α-hydroxymethyl acrylate isobornyl) ether, bis (α-hydroxymethyl acrylate adamantyl) ether, bis (α -Hydroxymethyl Although ethers of α- hydroxymethyl acrylate-based monomers such as acrylic acid benzyl) ether, present invention is not limited only to those exemplified. These monomers may be used alone or in combination of two or more. Among these, the initial adhesion to the substrate is excellent, and further, not only the environment actually used as a solar cell, but also an accelerated test in a high-temperature and high-humidity atmosphere that is being considered when evaluating solar cell modules ( From the viewpoint of obtaining an adhesive for solar cell modules having excellent adhesion to fillers used in solar cells even in the case of performing a moist heat resistance test), bis (α-hydroxymethylacrylic acid) ether, bis ( α-Hydroxymethyl acrylate) ether, bis (α-hydroxymethyl acrylate) ether, bis (α-hydroxymethyl acrylate) ether and bis (α-hydroxymethyl tert-butyl) ether are preferred.

  The content of the ring structure-containing unit represented by the formula (I) in the ring structure-containing (meth) acrylic polymer has a small blocking property, excellent initial adhesion to the substrate, and is actually used as a solar cell. Not only in the environment, but also in the high-temperature and high-humidity atmosphere that has been studied when evaluating solar cell modules, the adhesion to fillers used in solar cells From the viewpoint of obtaining an excellent adhesive for a solar cell module, it is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more. In addition to the environment that is actually used as a solar cell, the high-temperature and high-humidity atmosphere that is being studied when evaluating solar cell modules Even in the case where the accelerated test (moisture and heat resistance test) is performed, from the viewpoint of obtaining an adhesive for solar cell modules excellent in adhesiveness to fillers used in solar cells, it is 100% by mass or less, preferably 99% by mass. % Or less, more preferably 95% by mass or less, and still more preferably 90% by mass or less.

  In addition, the content rate of the ring structure containing unit represented by the formula (I) in the ring structure-containing (meth) acrylic polymer is equal to the formula (I) in the monomer component used as a raw material for the ring structure-containing (meth) acrylic polymer. It is calculated | required as a content rate of the diene structure containing monomer which gives the ring structure containing unit represented by this.

  The content of the diene structure-containing monomer in the monomer component is small in blocking properties, excellent in initial adhesion to the substrate, and evaluated not only in the environment where it is actually used as a solar cell, but also in solar cell modules Even when an accelerated test (moisture and heat resistance test) in a high-temperature and high-humidity atmosphere, which is being considered, is obtained, an adhesive for solar cell modules having excellent adhesion to fillers used in solar cells is obtained. From the viewpoint, it is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more, has a low blocking property, excellent initial adhesion to the substrate, and is actually used as a solar cell. Accelerated test (humid heat resistance test) in a hot and humid atmosphere, which is being considered when evaluating solar cell modules Even in such a case, from the viewpoint of obtaining an adhesive for a solar cell module excellent in adhesion to a filler used in a solar cell, it is 100% by mass or less, preferably 99% by mass or less, more preferably 95% by mass. Hereinafter, it is more preferably 90% by mass or less.

  The ring structure-containing (meth) acrylic polymer may contain a unit other than the unit having a ring structure containing a heteroatom within the range in which the object of the present invention is not inhibited. In other words, the monomer component may contain a monomer other than the diene structure-containing monomer. Examples of the monomer other than the diene structure-containing monomer include, for example, a monomer having a carboxyl group, an acidic phosphate ester monomer, a monomer having a group having an active hydrogen, and a (meth) acrylic ester. A monomer having an epoxy group, a monomer having a nitrogen atom, a monomer having two or more polymerizable double bonds, an aromatic monomer, a monomer having a halogen atom, a vinyl ester Monomers, vinyl ether monomers, and the like that do not have a ring structure containing a hetero atom can be mentioned, but the present invention is not limited to such examples. These monomers may be used alone or in combination of two or more.

  Examples of the monomer having a carboxyl group include aliphatic monocarboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, and maleic anhydride, but the present invention is not limited to such examples. Absent. These monomers having a carboxyl group may be used alone or in combination of two or more.

  Examples of acidic phosphate ester monomers include 2-acryloyloxyethyl acid phosphate and 2-methacryloyloxyethyl acid phosphate, but the present invention is not limited to such examples. These acidic phosphate ester monomers may be used alone or in combination of two or more.

  Examples of the monomer having a group having active hydrogen include hydroxyl group-containing aliphatic carboxylic acids such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and hydroxybutyl methacrylate. Although ester etc. are mentioned, this invention is not limited only to this illustration. These monomers having a group having active hydrogen may be used alone or in combination of two or more.

  Examples of (meth) acrylic acid esters include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, and tert. -(Meth) acrylic acid alkyl esters such as butyl acrylate, tert-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate; cycloalkyl (meth) such as isobornyl acrylate, isobornyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate Acrylate; cyclohexylmethyl acrylate, cyclohexylmethyl methacrylate Examples include cycloalkylalkyl (meth) acrylates such as rate, cyclohexylethyl acrylate, cyclohexylethyl methacrylate, cyclohexylpropyl acrylate, cyclohexylpropyl methacrylate, 4-methylcyclohexylmethyl acrylate, and 4-methylcyclohexylmethyl methacrylate. It is not limited only to such illustration. These (meth) acrylic acid esters may be used alone or in combination of two or more.

  Examples of the monomer having an epoxy group include epoxy group-containing (meth) acrylic acid esters such as glycidyl acrylate and glycidyl methacrylate, but the present invention is not limited to such examples. These monomers having an epoxy group may be used alone or in combination of two or more.

  Examples of the monomer having a nitrogen atom include (meth) acrylamide such as acrylamide and methacrylamide, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl acrylate, N , N-diethylaminoethyl methacrylate, imide acrylate, nitrogen atom-containing (meth) acrylate such as imide methacrylate, and the like are exemplified, but the present invention is not limited to such examples. These monomers having a nitrogen atom may be used alone or in combination of two or more.

  Examples of the monomer having two or more polymerizable double bonds include ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tripropylene glycol diacrylate, and tripropylene glycol. Dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, 2- (2-vinyloxyethoxy) ethyl acrylate, 2- (2-vinyloxyethoxy) ethyl methacrylate, allyl Although acrylate, allyl methacrylate, etc. are mentioned, this invention is not limited only to this illustration. These monomers having two or more polymerizable double bonds may be used alone or in combination of two or more.

  Examples of the aromatic monomer include styrene compounds such as styrene and α-methylstyrene, but the present invention is not limited to such examples. These aromatic monomers may be used alone or in combination of two or more.

  Examples of the monomer having a halogen atom include vinyl chloride, but the present invention is not limited to such examples. Only one type of monomer having a halogen atom may be used, or two or more types may be used in combination.

  Examples of the vinyl ester monomer include vinyl acetate, but the present invention is not limited to such examples. Only one type of vinyl ester monomer may be used, or two or more types may be used in combination.

  Examples of vinyl ether monomers include butyl vinyl ether and cyclohexyl vinyl ether, but the present invention is not limited to such examples. These vinyl ether monomers may be used alone or in combination of two or more.

  Among the monomers other than diene structure-containing monomers, not only the environment actually used as solar cells, but also accelerated tests (high heat and humidity resistance) in high-temperature and high-humidity atmospheres that are considered when evaluating solar cell modules. Even when the test is performed, weather resistance of cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tert-butyl (meth) acrylate, etc., from the viewpoint of improving the adhesion to the filler used in the solar cell A monomer having a property of imparting odor (hereinafter referred to as a weather-resistant monomer), a hydroxyl group-containing monomer such as 2-hydroxyethyl (meth) acrylate, caprolactone-modified (meth) acrylate, and the like are preferable.

  The content of the weatherable monomer in the monomer component is preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, particularly preferably from the viewpoint of improving weatherability. Is 5% by mass or more, and preferably 90% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less, and still more preferably 50% from the viewpoint of improving the brittleness of the adhesive for solar cell modules. It is below mass%.

  The content of the hydroxyl group-containing monomer in the monomer component is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, from the viewpoint of improving the durability of the adhesive for solar cell modules. The content is preferably 1% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less, from the viewpoint of enhancing hydrolysis resistance and insulation resistance.

  The monomer component preferably contains an acrylate having a basic structure of bisarylfluorene from the viewpoint of improving hydrolysis resistance and insulation resistance. An acrylate having a bisarylfluorene as a basic structure is easily commercially available as, for example, Osaka Gas Chemical Co., Ltd., trade names: Ogsol EA-0200, Ogsol EA-0200, Ogsol EA-0500, Ogsol EA-1000, etc. It can be obtained.

Further, cyclohexyl alkyl esters of (meth) acrylic acid, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meta) as disclosed in JP-A-2002-69130. ) Acrylate, tricyclo [5.2.1.0 ^2.6 ] dec-8-yl (meth) acrylate, terpene (meth) acrylate, and the like can also be used.

  In addition, the monomer component further includes a benzo such as 2- (2′-hydroxy-5′-methacryloyloxyethylphenyl) -2H-benzotriazole from the viewpoint of improving the adhesion to a filler used in solar cells. A monomer having an ultraviolet absorbing group, such as a monomer having a triazole ultraviolet absorbing group, a monomer having a benzophenone ultraviolet absorbing group, or a monomer having a triazine ultraviolet absorbing group; Monomers with UV-stable groups; including monomers that improve adhesion such as imide (meth) acrylate, morpholino (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified hydroxy (meth) acrylate It is preferable to make it. These monomers may be used alone or in combination of two or more.

  A monomer having an ultraviolet absorbing group can be easily obtained commercially, for example, as Otsuka Chemical Co., Ltd., trade name: RUVA93, Osaka Organic Chemical Industry Co., Ltd., trade name: BP-1A. Can do. Monomers having a UV-stable group can be easily obtained commercially as, for example, Adeka Stables such as Adeka Stab LA-82 and Adeka Stab LA-87 manufactured by ADEKA Corporation. Caprolactone-modified hydroxy (meth) acrylate can be easily obtained commercially, for example, as trade name: Plaxel FM1, Plaxel FM1D, Plaxel FM2D, Plaxel FM3, Plaxel FA1DM, Plaxel FA2D manufactured by Daicel Chemical Industries, Ltd. it can.

  The monomer component having a UV-absorbing group, a monomer having a UV-stable group, imide (meth) acrylate, morpholino (meth) acrylate, and tetrahydrofurfuryl (meth) acrylate From the viewpoint of improving the adhesiveness to the filler used in the battery, it is preferably 0.5% by mass or more, more preferably 1% by mass or more, and from the viewpoint of enhancing hydrolysis resistance and insulation resistance, preferably 40%. It is not more than mass%, more preferably not more than 30 mass%, still more preferably not more than 20 mass%.

  The content of caprolactone-modified hydroxy (meth) acrylate in the monomer component is preferably 5% by mass or more, more preferably 10% by mass or more, from the viewpoint of improving the adhesion to the filler used in the solar cell. From the viewpoint of preventing gelation when preparing a ring structure-containing (meth) acrylic polymer, it is preferably 40% by mass or less, more preferably 30% by mass or less, and still more preferably 20% by mass or less.

  When polymerizing the monomer component, a chain transfer agent may be used as necessary from the viewpoint of suppressing an increase in molecular weight distribution and gelation. Examples of the chain transfer agent include mercaptocarboxylic acids such as mercaptoacetic acid and 3-mercaptopropionic acid; methyl mercaptoacetate, methyl 3-mercaptopropionate, 2-ethylhexyl 3-mercaptopropionate, and n-octyl 3-mercaptopropionate. , Methoxybutyl 3-mercaptopropionate, stearyl 3-mercaptopropionate, trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercapto Mercaptocarboxylic esters such as propionate); alkyl such as ethyl mercaptan, tert-butyl mercaptan, n-dodecyl mercaptan, 1,2-dimercaptoethane Llucaptans; mercaptoalcohols such as 2-mercaptoethanol and 4-mercapto-1-butanol; aromatic mercaptans such as benzenethiol, m-toluenethiol, p-toluenethiol and 2-naphthalenethiol; tris [(3- Mercaptoisocyanurates such as mercaptopropionyloxy) -ethyl] isocyanurate; disulfides such as 2-hydroxyethyl disulfide and tetraethylthiuram disulfide; dithiocarbamates such as benzyldiethyldithiocarbamate; dimers such as α-methylstyrene dimer Alkyl halides such as carbon tetrabromide, and the like, but the present invention is not limited to such examples. These chain transfer agents may be used alone or in combination of two or more. Among these chain transfer agents, mercaptocarboxylic acids, mercaptocarboxylic acid esters, alkyl mercaptans are obtained because they are easily available, have excellent anti-crosslinking properties, and have a low degree of decrease in polymerization rate. Compounds having a mercapto group such as mercaptoalcohols, aromatic mercaptans and mercaptoisocyanurates are preferred.

  The amount of the chain transfer agent may be appropriately set according to the composition of the monomer component, the polymerization conditions such as the polymerization temperature, the molecular weight of the target ring structure-containing (meth) acrylic polymer, and is not particularly limited. When obtaining a ring structure-containing (meth) acrylic polymer having a weight average molecular weight of several thousand to several tens of thousands, it is preferably 0.1 to 20 parts by mass per 100 parts by mass of the monomer component. More preferably, it is -15 mass parts.

  Examples of the method for polymerizing the monomer component include a solution polymerization method, a dispersion polymerization method, a suspension polymerization method, an emulsion polymerization method, and the like, but the present invention is not limited to such examples.

  When the monomer component is polymerized by a solution polymerization method, examples of the solvent include aromatic solvents such as toluene and xylene; alcohol solvents such as isopropyl alcohol and n-butyl alcohol; propylene glycol methyl ether and dipropylene glycol methyl. Ether solvents such as ether, ethyl cellosolve, butyl cellosolve; ester solvents such as ethyl acetate, normal butyl acetate, cellosolve acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol; amides such as dimethylformamide Although organic solvents, such as a solvent, are mentioned, this invention is not limited only to this illustration. These solvents may be used alone or in combination of two or more. The amount of the solvent may be appropriately determined in consideration of the polymerization conditions, the composition of the monomer components, the concentration of the resulting ring structure-containing (meth) acrylic polymer, and the like.

  A polymerization initiator can be used when the monomer component is polymerized. Examples of the polymerization initiator include 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), tert-butylperoxy-2-ethylhexano And 2,2′-azobisisobutyronitrile, benzoyl peroxide, di-tert-butyl peroxide, and the like, but the present invention is not limited to such examples. These polymerization initiators may be used alone or in combination of two or more. The amount of the polymerization initiator may be appropriately set according to the desired physical properties of the obtained ring structure-containing (meth) acrylic polymer, and is usually preferably 0.01 to 100 parts by mass of the monomer component. 50 parts by mass, more preferably 0.05 to 20 parts by mass.

  The polymerization conditions for polymerizing the monomer components may be set as appropriate according to the polymerization method, and are not particularly limited. The polymerization temperature is preferably room temperature to 200 ° C, more preferably 40 to 140 ° C. What is necessary is just to set reaction time suitably so that the polymerization reaction of a monomer component may be completed.

  By polymerizing the monomer component as described above, a ring structure-containing (meth) acrylic polymer is obtained, and the ring structure-containing (meth) acrylic polymer is suitably used as a (meth) acrylic resin. be able to.

  The weight average molecular weight of the (meth) acrylic resin is preferably 2,000 to 1,000,000, more preferably 4,000 to 500,000, and still more preferably 5,000 to 300,000. The weight average molecular weight is a value when measured by gel permeation chromatography (GPC) with a polystyrene standard.

  From the viewpoint of suppressing blocking, the glass transition temperature of the (meth) acrylic resin (nonvolatile content) is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and the (meth) acrylic resin (nonvolatile content) of the (meth) acrylic resin (nonvolatile content). The upper limit of the glass transition temperature is preferably 150 ° C. or lower, more preferably 120 ° C. or lower.

  In addition, the hydroxyl value of the (meth) acrylic resin (non-volatile content) has a small blocking property, excellent initial adhesion to the substrate, and not only the environment actually used as a solar cell, but also a solar cell module. Even when an accelerated test (humidity heat resistance test) in a high-temperature and high-humidity atmosphere, which has been studied at the time of evaluation, an adhesive for solar cell modules having excellent adhesion to fillers used in solar cells is used. From the viewpoint of obtaining, it is preferably 0.4 to 200 mgKOH / g.

  Adhesives for solar cell modules have low blocking properties, excellent initial adhesion to the substrate, and are being studied not only in environments where solar cells are actually used, but also when evaluating solar cell modules. A thermoplastic resin, preferably from the viewpoint of obtaining an adhesive for a solar cell module excellent in adhesion to a filler used in a solar cell even when an accelerated test (humid heat resistance test) is performed in a humid atmosphere. Contains a (meth) acrylic resin, more preferably a ring structure-containing (meth) acrylic polymer.

  The content rate of the thermoplastic resin in the adhesive for solar cell modules can be easily adjusted, for example, by using the solvent. Although the content rate of the thermoplastic resin in the adhesive for solar cell modules is not specifically limited, Usually, it is 3-50 mass%.

  The content of the thermoplastic resin in the non-volatile content contained in the adhesive for the solar cell module is small in blocking property, excellent in initial adhesion to the substrate, and not only in the environment where it is actually used as a solar cell, but also in the sun. For solar cell modules with excellent adhesion to fillers used in solar cells, even when accelerated tests (moisture and heat resistance tests) in high-temperature and high-humidity atmospheres, which are being considered when evaluating battery modules From the viewpoint of obtaining an adhesive, it is preferably 40% by mass or more, more preferably 45% by mass or more. The non-volatile component of the solar cell module adhesive may be composed of only a thermoplastic resin.

  The adhesive layer made of the adhesive for solar cell modules of the present invention may be either crosslinked or uncrosslinked, but is preferably crosslinked from the viewpoint of improving hydrolysis resistance and insulation resistance. . The adhesive layer may be formed, for example, by independently crosslinking the solar cell module adhesive itself, or the solar cell module adhesive contains a curing agent, and the solar cell module adhesive is bonded with the curing agent. You may form by bridge | crosslinking an agent.

  However, it is preferable that the hardening | curing agent is contained from a viewpoint of improving the sclerosis | hardenability and weather resistance of the adhesive agent for solar cell modules.

  Examples of the curing agent include (block) polyisocyanate compounds, epoxy resins, oxazoline group-containing resins, aminoplast resins, and the like, and these may be used alone or in combination of two or more. Among these, from the viewpoint of improving curability and weather resistance, at least one selected from the group consisting of (block) polyisocyanate compounds, epoxy resins and oxazoline group-containing resins is preferable, and (block) polyisocyanate compounds are More preferred.

  The (block) polyisocyanate compound means a polyisocyanate compound and / or a block polyisocyanate compound.

  Examples of the polyisocyanate compound include compounds having at least two isocyanate groups in the molecule. Specific examples of the polyisocyanate compound include tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), lysine diisocyanate, trimethylhexamethylene diisocyanate, Polyisocyanates such as 1,3-bis (isocyanatomethyl) cyclohexane, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate; modified polyisocyanates such as adducts, burettes and isocyanurates of these polyisocyanates (Derivatives) and the like can be mentioned, but the present invention is not limited to such examples.

  Although a block polyisocyanate compound crosslinks the adhesive for solar cell modules by heating, it has the property and adhesiveness which improve storage stability at normal temperature. Moreover, the block polyisocyanate compound is not only in the environment where it is actually used as a solar cell, but also in a case where an accelerated test (humidity heat resistance test) is performed in a high-temperature and high-humidity atmosphere that is considered when evaluating solar cell modules. Even if it exists, it is excellent in the adhesiveness with respect to the filler used for a solar cell. The block polyisocyanate compound is usually one in which the isocyanate group of the polyisocyanate compound is blocked with a blocking agent. Examples of the blocking agent include ε-caprolactam, phenol, cresol, oxime, alcohol, and the like, but the present invention is not limited to such examples. Among the block polyisocyanate compounds, a non-yellowing polyisocyanate compound having no isocyanate group directly bonded to an aromatic ring is preferable from the viewpoint of preventing yellowing of the adhesive layer.

  (Block) Polyisocyanate compounds are, for example, manufactured by Sumika Bayer Urethane Co., Ltd., trade names: Death Module N3200, Death Module N3300, Death Module BL3175, Death Module N3400, Death Module N3600, Death Module VPLS2102, Sumidur BL3575MPA / X: manufactured by Asahi Kasei Chemicals Co., Ltd., trade name: Duranate E-402-90T, Duranate TPA-B80E, Duranate MF-B60X, Duranate MF-K60X, Duranate TSE-100, etc. .

  The amount of the (block) polyisocyanate compound is not particularly limited. For example, the amount of isocyanate groups in the (block) polyisocyanate compound per mole of hydroxyl groups in a thermoplastic resin such as a (meth) acrylic resin is preferably from the viewpoint of improving the adhesion to a filler used in a solar cell. Is 0.5 mol or more, more preferably 0.8 mol or more, and is preferably 10 mol or less, more preferably 7 mol or less from the viewpoint of increasing the curing rate.

  Examples of the epoxy resin include Japan Epoxy Resin Co., Ltd., trade names: Epicoat 828, Epicoat 1001X70, Epicoat 815; ADEKA Corporation, trade name: Adeka Resin EP-4100, and the like. It is not limited only to such illustration.

  Examples of the oxazoline group-containing resin include those manufactured by Nippon Shokubai Co., Ltd., trade names: Epocross K-2000 series, Epocross WS-500, Epocross WS-700, etc., but the present invention is limited to such examples. It is not something.

  An aminoplast resin is an addition condensate of a compound having an amino group such as melamine or guanamine with formaldehyde, and is also called an amino resin.

  Examples of aminoplast resins include dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine, fully alkyl methylated melamine, fully alkyl butylated melamine, fully alkyl isobutylated melamine, completely Melamine resins such as alkyl mixed etherified melamine, methylol group methylated melamine, imino group methylated melamine, methylol group mixed etherified melamine, imino group mixed etherified melamine; butylated benzoguanamine, methyl / ethyl mixed alkyl Benzoguanamine, methyl / butyl mixed alkylated benzoguanamine, guanamine resins such as butylated glycoluril, and the like, but the present invention is limited only to such examples. Not to.

  Aminoplast resins are commercially available, for example, as Mitsui Cytec Co., Ltd., trade names: Cymel 1128, Cymel 303, My Coat 506, Cymel 232, Cymel 235, Cymel 771, Cymel 325, Cymel 272, Cymel 254, Cymel 1170, and the like. Can be easily obtained.

  The amount of aminoplast resin is not particularly limited. The mass ratio [thermoplastic resin / aminoplast resin] of the solid content of the thermoplastic resin and aminoplast resin is preferably 6/4 or more from the viewpoint of improving the adhesiveness to the filler used in the solar cell, From the viewpoint of improving the hydrolysis resistance and adhesiveness of the adhesive layer, it is preferably 9/1 or less.

  The amount of the curing agent varies depending on the type of the curing agent and cannot be determined unconditionally. Usually, however, from the viewpoint of hydrolysis resistance and insulation resistance of the adhesive layer with respect to 100 parts by mass of the thermoplastic resin. From the viewpoint of improving the adhesiveness to the filler used in the solar cell, preferably 60 parts by mass or less, more preferably 50 parts by mass or less, preferably 1 part by mass or more, more preferably 3 parts by mass or more. More preferably, it is 30 mass parts or less. For example, when a (meth) acrylic resin having a plurality of hydroxyl groups in one molecule is used as the thermoplastic resin, the amount of the curing agent is cured according to the number of hydroxyl groups of the (meth) acrylic resin. You may adjust the quantity of an agent suitably.

  The adhesive for solar cell modules can be cured under various curing conditions depending on the use of the adhesive for solar cell modules, the type of curing agent used in the adhesive for solar cell modules, and the like. The adhesive for solar cell modules can be used as a room temperature curing type, a heat curing type, an ultraviolet curing type, or an electron beam curing type. Moreover, there is no limitation in particular in the addition method or dispersion method of a hardening | curing agent. For example, when a (meth) acrylic resin having a plurality of hydroxyl groups in one molecule is used as a thermoplastic resin, a method of adding a curing agent or a dispersing method is selected according to the type of the (meth) acrylic resin. do it.

  The adhesive for solar cell modules of the present invention contains a thermoplastic resin, a curing agent and plate-like particles. Since the adhesive for solar cell modules of the present invention contains a thermoplastic resin, a curing agent and plate-like particles as described above, the blocking property is small, the initial adhesion to the substrate is excellent, and the solar cell module is actually used as a solar cell. Not only the environment in which the solar cell module is used, but also the case where an accelerated test (humid heat resistance test) in a high-temperature and high-humidity atmosphere, which is being considered when evaluating solar cell modules, Excellent adhesion.

  Examples of the plate-like particles include layered particles, flat particles, scaly particles, tabular particles, and the like, but the present invention is not limited to such examples. Specific examples of the plate-like particles include, for example, alkali metals such as potassium, alkaline earth metals such as magnesium and calcium, typical metals such as graphite, aluminum, zinc and tin, iron, nickel, copper, manganese, silver and platinum Plate-like metal particles made of transition metals such as alumina; silica, titania, zirconia, magnesia, yttria, zinc oxide, iron oxide, silicon nitride, titanium nitride, boron nitride, silicon carbide, light calcium carbonate, heavy Calcium carbonate, aluminum sulfate, magnesium hydroxide, aluminum hydroxide, potassium titanate, talc, kaolin (kaolin clay), kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, muscovite, sericite ( Sericite), phlogopite ( Mica, sodium teniolite, lithium teniolite, hydrotalc, glass flake, amethite, bentonite, zeolite, calcium silicate, magnesium silicate Plate-like inorganic particles made of inorganic materials such as diatomaceous earth and silica sand; plate-like organic particles made of organic materials such as lauroyl taurine calcium and lauroyl lysine, and the like, but the present invention is limited to such examples only. It is not something. These plate-like particles may be used alone or in combination of two or more. Among these plate-like particles, excellent initial adhesion to the base material, and also in a high-temperature and high-humidity atmosphere that is being considered when evaluating solar cell modules as well as the environment actually used as solar cells. Even when the acceleration test (moisture and heat resistance test) is performed, talc and kaolin are preferred because of their excellent adhesion to fillers used in solar cells. Examples of kaolin include dry kaolin, wet kaolin, and calcined kaolin depending on the production method, and any of them can be used in the present invention.

  If necessary, the plate-like particles may be subjected to a surface treatment. Surface treatment includes, for example, silane coupling treatment, titanate treatment, oxidation treatment, resin coating treatment, energy ray irradiation treatment, electrochemical treatment, and the like, saturated fatty acids such as stearic acid, oleic acid, linoleic acid and the like. Although the process etc. which adsorb | suck a saturated fatty acid to plate-like particle | grains are mentioned, this invention is not limited only to this illustration.

  The average particle diameter of the plate-like particles is preferably 100 nm or more, more preferably 200 nm or more, and further preferably 250 nm or more from the viewpoint of obtaining an adhesive for a solar cell module having a small blocking property, and the initial adhesion to the substrate. Even when an accelerated test (humid heat resistance test) is performed in a high-temperature and high-humidity atmosphere, which is being considered when evaluating solar cell modules, as well as in the environment where solar cells are actually used. From the viewpoint of obtaining an adhesive for a solar cell module excellent in adhesiveness to a filler used in a solar cell, it is preferably 15 μm or less, more preferably 12 μm or less, and further preferably 5 μm or less.

  Moreover, the adhesive for solar cell modules has an average particle diameter from the viewpoint of improving slip resistance and suppressing blocking by forming irregularities on the surface of the adhesive layer formed from the adhesive for solar cell modules. It is preferable to contain particles that are 0.2 μm or more and 1.1 times or less the thickness of the adhesive layer. The average particle diameter of the particles is preferably 0.3 μm or more, more preferably 0.5 μm or more from the viewpoint of improving slip resistance and suppressing blocking, and improves concealability in the adhesive layer and adheres. From the viewpoint of improving the weather resistance of the adhesive layer, it is preferably 1.3 times or less of the thickness of the adhesive layer, more preferably 1.1 times or less of the thickness of the adhesive layer.

  The average particle size of the particles is obtained by, for example, adding particles in a hydrophilic solvent such as water and methanol, and stirring the hydrophilic solvent to quickly collect particles uniformly dispersed, The volume average particle diameter can be determined using a particle size distribution measuring apparatus (product number: LA910) manufactured by Horiba, Ltd. In the case of particles having a high true specific gravity and whose volume average particle size is difficult to measure using the particle size distribution measuring device, the particles are measured using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). Observe and determine the diameter of spherical particles, the intermediate value of single and long diameters of elliptical particles, and the intermediate value of short and long sides of irregular particles, and create the particle size distribution of the particles And the average value of a particle diameter is calculated | required based on the particle diameter distribution, and this average value can be made into the average particle diameter of particle | grains.

  The aspect ratio of the plate-like particles is preferably 3 or more, more preferably 5 or more, and even more preferably 10 or more from the viewpoint of improving thermal conductivity. When the adhesive resin and the plate-like particles are mixed, the aspect ratio From the viewpoint of suppressing the increase in viscosity, it is preferably 100 or less, more preferably 90 or less, and still more preferably 80 or less.

The aspect ratio of the plate-like particle is a value obtained by dividing the maximum length in the plane direction of the plate-like particle by the maximum thickness of the plate-like particle. In other words, the aspect ratio of the plate-like particle is given by the formula:
[Aspect ratio of plate-like particles]
= [Maximum length in the plane direction of plate-like particles] ÷ [Maximum thickness of plate-like particles]
Based on.

  The maximum length and the maximum thickness in the plane direction of the plate-like particles are determined by directly observing the plate-like particles with a scanning electron microscope or the like, and for each arbitrarily selected plate-like particle, the maximum length and the maximum thickness are determined. It can be measured and obtained as an average value in the measured number. The number of plate-like particles to be measured when measuring the maximum length and the maximum thickness is not particularly limited, but is preferably about 10 to 20 from the viewpoint of improving accuracy and convenience of measurement. The maximum length and the maximum thickness of the plate-like particles contained in the thermally conductive material layer are measured for the plate-like particles separated by dissolving the thermally conductive material layer with a solvent such as an organic solvent. Can be determined by

  In the present specification, the length and thickness in the plane direction of the plate-like particles mean the maximum length and the maximum thickness in the plane direction of one plate-like particle for convenience.

  From the viewpoint of improving thermal conductivity, the maximum thickness of the plate-like particles is preferably 0.01 μm or more, more preferably 0.015 μm or more, still more preferably 0.02 μm or more, and further preferably 0.05 μm or more. From the viewpoint of suppressing thickening with time when the adhesive resin and the plate-like particles are mixed, it is preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less, and still more preferably 0.8. 5 μm or less, still more preferably 0.4 μm or less, particularly preferably 0.3 μm or less.

  The maximum length in the plane direction of the plate-like particles is preferably 0.1 μm or more, more preferably 0.2 μm or more, and further preferably 0.3 μm or more from the viewpoint of improving thermal conductivity. From the viewpoint of suppressing thickening with time when mixed with plate-like particles, it is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, even more preferably 15 μm or less, and even more preferably 10 μm. It is as follows.

  The amount of the plate-like particles is small in blocking property, excellent in initial adhesion to the substrate, and is not only used in an environment where solar cells are actually used, but also in high-temperature and high-humidity studied when evaluating solar cell modules. From the viewpoint of obtaining an adhesive for solar cell modules having excellent adhesion to fillers used in solar cells, even when an accelerated test (moisture heat resistance test) is performed in an atmosphere of Min) per 100 parts by mass, preferably 0.1 to 300 parts by mass, more preferably 0.3 to 200 parts by mass, and even more preferably 1 to 100 parts by mass.

  In the present invention, particles other than the plate-like particles such as a pigment may be included within a range in which the object of the present invention is not hindered.

  Moreover, the adhesive for solar cell modules may contain an appropriate amount of a crosslinking accelerator as necessary. Examples of crosslinking accelerators include dibutyltin dilaurate, tin octoate, dibutyltin di (2-ethylhexanoate), 2-ethylhexanoate lead, 2-ethylhexyl titanate, 2-ethylhexanoate iron, Examples include 2-ethylhexanoate cobalt, zinc naphthenate, cobalt naphthenate, tin octoate, bismuth octoate, tetra-n-butyltin, diisopropoxytitanium bis (ethylacetoacetate), and zirconium tetraacetylacetonate. The present invention is not limited to such examples. These crosslinking accelerators may be used alone or in combination of two or more.

  In the present invention, an appropriate amount of a dye can be used as a colorant. Examples of the dye include natural dyes and chemical dyes. Examples of natural dyes include safflower, saffron, and shellfish purple, and these may be used alone or in combination of two or more. Examples of chemical dyes include acid dyes, basic dyes, direct dyes, reactive dyes, oil-soluble dyes, mordant dyes, reactive dyes, etc., and these may be used alone or in combination of two or more. You may use together. Examples of the acid dye include C.I. I. Acid Black 2, C.I. I. Acid Black 52, C.I. I. Acid Yellow 23, C.I. I. Acid Red 51, C.I. I. Add Red 87 and the like. Examples of basic dyes include C.I. I. Basic Black 2, C.I. I. Basic Yellow 2, C.I. I. Basic Yellow 11, C.I. I. Basic Red 1, C.I. I. Basic Red 13, C.I. I. Basic Violet 1, C.I. I. Basic Violet 3, C.I. I. Basic Violet 7, C.I. I. Basic Blue 5, C.I. I. Basic Blue 7 and the like may be mentioned, and these may be used alone or in combination of two or more. Examples of the direct dye include C.I. I. Direct Black 19, C.I. I. Direct Black 22, C.I. I. Direct Black 38, C.I. I. Direct black 51 etc. are mentioned, These may each be used independently and may use 2 or more types together. Examples of reactive dyes include C.I. I. Reactive Black 4, C.I. I. Reactive Black 39, C.I. I. Reactive Red 180 and the like may be mentioned, and these may be used alone or in combination of two or more. Examples of oil-soluble dyes include C.I. I. Solvent Black 3, C.I. I. Solvent Black 5, C.I. I. Solvent Black 7 etc. are mentioned, These may be used independently, respectively, and may use 2 or more types together. Examples of mordant dyes include C.I. I. Modern black 17 etc. are mentioned, These may be used independently, respectively, and may use 2 or more types together. Examples of reactive dyes include C.I. I. Reactive Black 4, C.I. I. Reactive black 39 etc. are mentioned, These may be used independently, respectively and may use 2 or more types together. Examples of the black dye include C.I. I. Direct Black 19, C.I. I. Direct Black 22, C.I. I. Direct Black 38, C.I. I. Black direct dyes such as direct black 51, C.I. I. Acid Black 2, C.I. I. Black acid dyes such as Acid Black 52, C.I. I. Black basic dyes such as basic black 2, C.I. I. Solvent Black 3, C.I. I. Solvent Black 5, C.I. I. Black oil-soluble dyes such as Solvent Black 7, C.I. I. Mordanting dyes such as Modern Black 17, C.I. I. Reactive Black 4, C.I. I. Although black reactive dyes, such as reactive black 39, etc. are mentioned, this invention is not limited only to this illustration.

  The adhesive for solar cell module of the present invention may contain a solvent, an additive and the like. Examples of the solvent include the same organic solvents as described above. Moreover, as an additive, the additive etc. which are generally used for the resin composition which forms a film, a coating film, etc. are mentioned.

  Specific examples of additives include leveling agents; antifoaming agents; sagging inhibitors; silane coupling agents; dispersants; antioxidants such as phosphorus antioxidants and phenolic antioxidants; viscosity modifiers; Agent; Metal deactivator; Peroxide decomposing agent; Flame retardant; Reinforcing agent; Plasticizer; Lubricant; Rust preventive agent; Fluorescent whitening agent; Organic and inorganic UV absorber, Inorganic heat ray absorption Examples thereof include organic and inorganic flameproofing agents; organic and inorganic antistatic agents; and dehydrating agents such as methyl orthoformate, but the present invention is not limited to such examples.

  Since the amount of the curing catalyst, solvent and additive varies depending on the type of the catalyst and cannot be determined unconditionally, it should be appropriately adjusted according to the properties required for the solar cell module adhesive of the present invention. Is preferred.

  In addition, the adhesive agent for solar cell modules of this invention can be made to contain a dispersing agent from a viewpoint of improving the dispersibility of plate-like particle | grains and the storage stability of the adhesive agent for solar cell modules. Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a salt of a long chain polyaminoamide and a polar acid ester, and a high molecular weight unsaturated. Examples include acid esters, modified polyurethanes, modified polyacrylates, polyether ester type anionic surfactants, polyoxyethylene alkyl phosphate esters, polyoxyethylene nonyl phenyl ether, stearylamine acetate, and synergists. It is not limited to illustration only.

  Dispersants are commercially available. Examples thereof include BYK Chemie, trade name: Disperbyk-101 (a salt of a long-chain polyaminoamide and a polar acid ester), Disperbyk-106 (acid group). Polymer salt), Disperbyk-110 (copolymer containing acid group), Disperbyk-130 (polyaminoamide), Disperbyk-2164 (amine-containing polymer), etc .; manufactured by Enomoto Kasei Co., Ltd., trade name: Disparon DA-703 -50 (polyaminoamide), Disparon KS-860 (polyesteramine salt), Disparon 2150 (aliphatic polycarboxylic acid), Disparon 7004 (polyetherester), etc .; Nippon Lubrizol Co., Ltd., trade name: Solspers 5000 The Solspurs 2000 (phthalocyanine ammonium salt), Solspers 13940 (polyesteramine), Solspers 17000 (fatty acid amines), Solspers 24000 and the like; However, the present invention is not limited to such examples. These dispersants may be used alone or in combination of two or more.

  Since the content rate of the dispersing agent in the adhesive for solar cell modules of the present invention varies depending on the type, it cannot be determined unconditionally, but it is usually preferably about 0.1 to 10% by mass.

  In the present invention, from the viewpoint of improving the adhesiveness to the filler used for solar cells, examples of the adhesive for solar cell modules include polyester resins, modified polyolefin resins, EVA, polyvinyl butyral (PVB), and silicone resins. Further, a thermoplastic resin such as vinyl chloride resin, polyurethane, and amino group-containing resin, and a tackifier may be contained.

  Examples of the polyester resin include Toyobo Co., Ltd., trade names: Byron (registered trademark) 103, 240, 500, GK110, GK640, etc .; Nippon Synthetic Chemical Industry Co., Ltd., trade name: Nichigo Polyester (Registered Trademark) TP-220, TP-235, TP-236, TP-290, and the like can be mentioned, but the present invention is not limited to such examples.

  Examples of the modified olefin-based resin include, for example, Nippon Paper Chemicals Co., Ltd., trade name: Auroren (registered trademark) 100, 200, 350, S-5189, etc .; Sanyo Chemical Industries, Ltd., trade name: Umex 1001 1010, 2000, and the like, but the present invention is not limited to such examples.

  Examples of the EVA include Tosoh Corporation, trade names: Mersen (registered trademark) H-6051, H-6410, etc .; Sumitomo Chemical Co., Ltd., trade names: Sumitate (registered trademark) KA-31, KA Although -42 etc. are mentioned, this invention is not limited only to this illustration.

  Examples of the polyvinyl butyral (PVB) include those manufactured by Kuraray Co., Ltd., and trade names: Mowital (registered trademark) series B30H, B45M, B60H, and the like. However, the present invention is not limited to such examples. Absent.

  Examples of the silicone resin include Shin-Etsu Chemical Co., Ltd., product numbers: KE-103 and KE-1013, but the present invention is not limited to such examples.

  Examples of the vinyl chloride resin include Sekisui Chemical Co., Ltd., trade name: Sekisui PVCTS, but the present invention is not limited to such examples.

  Examples of the polyurethane include DIC Bayer Polymer Co., Ltd., trade name: Desmopan DP6580A, but the present invention is not limited to such examples.

  Examples of the amino group-containing resin include those manufactured by Nippon Shokubai Co., Ltd., trade names: Poliment NK-350, NK-380, etc., but the present invention is not limited to such examples.

  Examples of the tackifier include rosin tackifiers; rosin ester tackifiers, terpene tackifiers, terpene phenol tackifiers, saturated hydrocarbon resins, and coumarone tackifiers. Agents, coumarone-indene tackifiers, styrene resin tackifiers, xylene resin tackifiers, phenol resin tackifiers, petroleum resin tackifiers, and the like. Is not limited to such examples. These tackifiers may be used alone or in combination of two or more.

  Examples of the rosin-based tackifier include those manufactured by Harima Kasei Co., Ltd. and trade name: Harrier Star DS-90, but the present invention is not limited to such examples.

  Examples of the rosin ester tackifier include Arakawa Chemical Industries, Ltd., trade names: Pine Crystal KE-100, KE-311, and the like, but the present invention is limited to such examples. It is not a thing.

  Examples of the terpene tackifier include trade names: Clearon (registered trademark) M-115 and P-115 manufactured by Yasuhara Chemical Co., Ltd., but the present invention is limited to such examples. It is not a thing.

  Examples of the terpene phenol tackifier include Arakawa Chemical Industries, Ltd., trade name: Tanomaru 803L, and the like, but the present invention is not limited to such examples.

  Examples of the saturated hydrocarbon resin include Arakawa Chemical Industries, Ltd., trade names: Alcon P-90 and P-100, but the present invention is not limited to such examples.

  Examples of the styrene resin-based tackifier include Mitsui Chemicals, Inc., product number: FTR-6000, but the present invention is not limited to such examples.

  The amount of the tackifier may be appropriately adjusted according to the desired tackiness, and is not particularly limited. However, from the viewpoint of improving the tackiness to the adherend per 100 parts by mass of the thermoplastic resin, preferably 3 masses. Part or more, more preferably 5 parts by weight or more, and preferably 200 parts by weight or less, more preferably 150 parts by weight or less, from the viewpoint of suppressing a decrease in adhesive strength.

  The adhesive for solar cell modules can also be used when bonding substrates used as back sheets for solar cell modules.

  Examples of suitable base materials include polyester base materials, polycarbonate base materials, fluororesin base materials, acrylic resin base materials, and the like. Of these, polyester base materials and fluororesin base materials are preferred from the viewpoint of weather resistance and cost. Although the thickness of a base material is not specifically limited, Usually, it is preferable that it is about 10-800 micrometers.

  Examples of the polyester used for the polyester-based substrate include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polycyclohexanedimethanol terephthalate, and the like, but the present invention is not limited to such examples. These polyesters may be used alone or in combination of two or more.

  Examples of the fluororesin used for the fluororesin-based substrate include polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, polyethylene tetrafluoroethylene, polytetrafluoroethylene, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. And tetrafluoroethylene-hexafluoropropylene copolymer, and the like, but the present invention is not limited to such examples. These fluororesins may be used alone or in combination of two or more.

  Further, in the present invention, in addition to the above-mentioned base material, a resin such as a polyolefin resin, a polyamide resin, or a polyarylate resin is considered in consideration of heat resistance, strength physical properties, electrical insulation properties, hydrolysis resistance, and the like. The base material which consists of can be used.

  In addition, as a filler used for a solar cell, EVA, polyvinyl butyral, a silicone resin, a vinyl chloride resin, a polyurethane etc. are mentioned, for example, This invention is not limited only to this illustration. Among these, EVA is preferable from the viewpoint of weather resistance and flame retardancy.

  In the solar cell module backsheet of the present invention, the thickness after drying of the adhesive layer made of the adhesive for solar cell modules formed on the surface to be bonded to the filler constituting the solar cell module is adhesive and From the viewpoint of weather resistance, it is preferably 0.1 μm or more, more preferably 0.3 μm or more, further preferably 1 μm or more, and from the viewpoint of preventing embrittlement, preferably 50 μm or less, more preferably 30 μm or less, still more preferably 20 μm or less.

  FIG. 1 is a schematic cross-sectional view showing the configuration when the substrate is bonded to the solar cell module adhesive. FIG. 1 is a schematic cross-sectional view showing one embodiment of a back sheet for a solar cell module of the present invention, and has the simplest structure. The two base materials 1 and 1 are bonded together with an adhesive 2. The base materials 1 and 1 may be base materials made of the same material, or may be base materials made of different materials.

  Examples of the adhesive 2 include an adhesive for a solar cell module, a polyester-based adhesive, a polyurethane-based adhesive, and a polycarbonate-based adhesive, but the present invention is not limited to such examples. It is preferable that the said adhesive for solar cell modules is an adhesive for solar cell modules used for the adhesive layer of the back sheet for solar cell modules of this invention from a viewpoint of adhesiveness and a weather resistance. An adhesive layer 4 containing a solar cell module adhesive is formed on one surface of the two substrates 1 and 1.

  In the solar cell module backsheet of the present invention, since the adhesive layer 4 containing the solar cell module adhesive is formed, not only the environment actually used as a solar cell but also the solar cell module is evaluated. Even when an accelerated test (humidity heat resistance test) in a high-temperature and high-humidity atmosphere, which is considered when performing, is excellent in adhesion and weather resistance to fillers used in solar cells, and has electrical output characteristics In order to make the stain due to the colored resin layer inconspicuous, it has excellent non-adhesiveness to the fluororesin film used in the production of solar cell modules without using a transparent layer, has a good appearance, and is also foldable The excellent effect of being excellent is exhibited.

  FIG. 2 is a schematic cross-sectional view of a solar cell module backsheet with a barrier layer 3 interposed therebetween as another embodiment of the solar cell module backsheet of the present invention.

  In FIG. 2, adhesives 2 and 2 are applied to one surface of each of the two substrates 1 and 1, and between the layers of the adhesives 2 and 2 formed on the two substrates 1 and 1. A thermoplastic resin such as a (meth) acrylic resin and a colorant on the surface to be bonded to the filler constituting the solar cell module by interposing a barrier layer 3 such as a gas barrier layer on the substrate The solar cell module backsheet is formed by forming an adhesive layer made of an adhesive for solar cell modules containing. Also in the solar cell module backsheet of this embodiment, since the adhesive layer 4 containing the solar cell module adhesive is formed, not only the environment actually used as a solar cell, but also the solar cell module Even when the accelerated test (humidity heat resistance test) is performed in a high-temperature and high-humidity atmosphere, which is considered for evaluation, it has excellent adhesion and weather resistance to fillers used in solar cells and maintains electrical output characteristics. In addition, in order to make dirt due to the colored resin layer inconspicuous, it has excellent non-adhesiveness to the fluororesin film used at the time of manufacturing a solar cell module without using a transparent layer, has a good appearance, and is foldable The excellent effect of being excellent is also achieved.

  Among the back sheet for solar cell module shown in FIG. 1 and the back sheet for solar cell module shown in FIG. 2, the back sheet for solar cell module shown in FIG. 1 is preferable from the viewpoint of cost reduction of the back sheet. .

  Examples of the gas barrier layer 3 shown in FIG. 2 include a vapor deposition substrate on which an oxide such as a metal foil, a metal vapor deposition film, and an oxide vapor deposition film is vapor-deposited.

  Examples of the metal foil include an aluminum foil. As a metal vapor deposition film, the aluminum vapor deposition film etc. which vapor-deposited aluminum on the polyester film and the polyolefin-type stretched film are mentioned, for example.

  As an oxide vapor deposition film, for example, aluminum oxide, silicon dioxide, tin oxide, magnesium oxide, indium oxide, a composite oxide of these, etc. is deposited on a polyester film. Examples thereof include those having gas barrier properties. In these, the film which vapor-deposited silicon dioxide on the polyester film and the film which vapor-deposited aluminum oxide on the polyester film are preferable.

  In the oxide vapor deposition film, the thickness of a suitable oxide vapor deposition layer varies depending on the type and composition of the oxide, but in general, from the viewpoint of forming a uniform oxide vapor deposition layer, preferably 5 nm or more, more preferably Is 10 nm or more, and is preferably 300 nm or less, more preferably 150 nm or less, from the viewpoint of imparting flexibility and preventing cracks from being generated by external stress.

  Examples of the method for forming the oxide vapor deposition layer on the film include a vacuum vapor deposition method, a sputtering method that is a thin film formation method, an ion plating method, a plasma vapor deposition method (CVD), and the like. The present invention is not limited to such examples.

  From the viewpoint of stabilizing and improving the gas barrier property of the solar cell module backsheet of the present invention, for example, an undercoat layer made of an acrylic polyol, an isocyanate compound, and a silane compound may be provided on the base material, An overcoat layer composed of a portion of polyvinyl alcohol or a completely saponified product and a silane compound may be provided on the deposited layer of the product.

  The back sheet for the solar cell module of the present invention is an adhesive so that the film thickness after drying becomes 0.1 to 20 μm by a method such as gravure coating, roll coating, bar coating, reverse coating on a substrate, for example. An adhesive comprising a solar cell module adhesive on the surface to be bonded to the filler constituting the solar cell module, after the other base material is bonded to the base material by a method such as dry lamination. It can be manufactured by forming a layer. At this time, the substrate may be subjected to a surface treatment for improving adhesiveness such as corona treatment, flame treatment, and plasma treatment, if necessary. For example, when a base material made of a fluororesin is used as the base material, it is preferable to perform plasma treatment or the like on the base material.

  The solar cell module using the back sheet for the solar cell module of the present invention is not only an environment actually used as a solar cell, but also an accelerated test in a high-temperature and high-humidity atmosphere to be considered when evaluating the solar cell module. Even when the (moisture and heat resistance test) is performed, the adhesive and the weather resistance with respect to the filler used for the solar cell are excellent, and the excellent effect of maintaining the electrical output characteristics is exhibited.

  The solar cell module of the present invention can be easily configured by replacing the back sheet for the solar cell module of the present invention as a back sheet in, for example, a commonly used solar cell module. Moreover, the solar cell of this invention can be easily comprised by replacing a solar cell module with the solar cell module of this invention in the solar cell generally used, for example.

  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited only to this Example.

The following were used as the substrate or filler.
<Substrate 1>
Toray Industries, Inc., trade name: Lumirror X10S [heat-resistant oligomer polyethylene terephthalate (hereinafter referred to as PET) film]
<Substrate 2>
Product name: Tech Barrier (silicon dioxide vapor-deposited PET film), manufactured by Mitsubishi Plastics Co., Ltd.
<Substrate 3>
Product name: Lumirror X10S (heat-resistant oligomer PET film), manufactured by Toray Industries, Inc.
<Filler>
Product name: Fast Cure, Product Number: RC01 (EVA sheet having a thickness of 400 nm), manufactured by Mitsui Chemicals Fabro Co., Ltd.

Synthesis example 1
As a reaction tank, a 2000 ml 4-neck separable flask equipped with a thermometer, a cooling pipe, a gas introduction pipe and a stirring device was prepared. After replacing the inside of the reaction tank with nitrogen gas, 266.7 g of ethyl acetate was charged into the reaction tank, and the temperature was raised to 60 ° C.

  On the other hand, a monomer component composed of 310.9 g of methyl α-allyloxymethyl acrylate, 31.7 g of 2-hydroxyethyl methacrylate and 48.0 g of isobornyl methacrylate was placed in dropping tank A, and polymerization was performed in dropping tank B. As the initiator, a mixture consisting of 1.0 g of 2,2′-azobis (2,4-dimethylvaleronitrile) and 80.0 g of ethyl acetate was added.

  After confirming that the internal temperature of the reaction vessel was stable, dropwise addition of the monomer component in the dropping vessel A and the mixture in the dropping vessel B was started simultaneously, and the internal temperature was adjusted to 60 to 63 ° C. for 3 hours. It was dripped over. After completion of the dropwise addition, the internal temperature of the reaction vessel was raised to 78 to 80 ° C., and the content of the reaction vessel was heated for 2 hours with stirring, and then 216.0 g of ethyl acetate was added to the content, whereby the nonvolatile content was reduced. A 39.8 mass% (meth) acrylic resin solution was obtained. The obtained (meth) acrylic resin (hereinafter referred to as polymer 1) had a weight average molecular weight of 75000, and the hydroxyl value of polymer 1 (nonvolatile content) was 39 mgKOH / g.

Production Example 1
100 parts by mass of the polymer 1 [(meth) acrylic resin] obtained in Synthesis Example 1, talc as a fine plate-like fine particle [manufactured by Nippon Talc Co., Ltd., trade name: fine talc nanoace SG-2000, average particle size: 1 μm The maximum thickness of the plate-like particles: 0.11 μm, the maximum length in the plane direction of the plate-like particles: 1.11 μm, the aspect ratio: 10.1] 28 parts by mass and a polyfunctional isocyanate compound [Suika Bayer Urethane Co., Ltd. Product name: Desmodur N3200] Adhesive 1 was obtained by sufficiently stirring and mixing 20 parts by mass.

Production Example 2
100 parts by mass of polymer 1 [(meth) acrylic resin] obtained in Synthesis Example 1, dry kaolin as a plate-shaped fine particle (manufactured by Takehara Chemical Industry Co., Ltd., trade name: Champion Cray, average particle diameter: 1 μm, plate-like) Maximum thickness of particles: 0.054 μm, maximum length in the plane direction of plate-like particles: 0.90 μm, aspect ratio: 16.7] 43 parts by mass and polyfunctional isocyanate compound [manufactured by Sumika Bayer Urethane Co., Ltd., Product name: Desmodur N3200] Adhesive 2 was obtained by sufficiently stirring and mixing 14 parts by mass.

Production Example 3
100 parts by mass of the polymer 1 [(meth) acrylic resin] obtained in Synthesis Example 1, wet kaolin as a plate-like fine particle [manufactured by Takehara Chemical Co., Ltd., trade name: ASP-170, average particle size: 0.8 μm The maximum thickness of the plate-like particles: 0.051 μm, the maximum length in the plane direction of the plate-like particles: 0.74 μm, the aspect ratio: 14.5] and 43 parts by mass of a polyfunctional isocyanate compound [Suika Bayer Urethane Co., Ltd. Product name: Death module N3200] Adhesive 3 was obtained by sufficiently stirring and mixing 14 parts by mass.

Production Example 4
100 parts by mass of polymer 1 [(meth) acrylic resin] obtained in Synthesis Example 1, wet kaolin as a fine plate-like fine particle (manufactured by Takehara Chemical Industry Co., Ltd., trade name: SAINTONE 5HB, average particle size: 0.4 μm, Maximum thickness of plate-like particles: 0.065 μm, maximum length in the plane direction of plate-like particles: 0.51 μm, aspect ratio: 7.8] 43 parts by mass and polyfunctional isocyanate compound [Sumika Bayer Urethane Co., Ltd.] Product name: Desmodur N3200] Adhesive 4 was obtained by sufficiently stirring and mixing 14 parts by mass.

Production Example 5
100 parts by mass of polymer 1 [(meth) acrylic resin] obtained in Synthesis Example 1, talc as a fine plate-like fine particle (manufactured by Nippon Talc Co., Ltd., trade name: fine powder talc / microace SG-95, average particle diameter: 2.5 μm, maximum thickness of plate-like particles: 0.160 μm, maximum length in the plane direction of plate-like particles: 2.73 μm, aspect ratio: 17.1] 27 parts by mass and polyfunctional isocyanate compound [Suika Bayer Urethane Co., Ltd., trade name: Desmodur N3200] Adhesive 5 was obtained by sufficiently stirring and mixing 28 parts by mass.

Production Example 6
100 parts by mass of the polymer 1 [(meth) acrylic resin] obtained in Synthesis Example 1 and talc as a flat fine particle [manufactured by Nippon Talc Co., Ltd., trade name: fine talc / microace P-6, average particle size: 4 μm, the maximum thickness of the plate-like particles: 0.184 μm, the maximum length in the plane direction of the plate-like particles: 5.35 μm, the aspect ratio: 29.1] 24 parts by mass and a polyfunctional isocyanate compound [Suika Bayer Urethane ( Co., Ltd., trade name: Death Module N3200] Adhesive 6 was obtained by sufficiently stirring and mixing 15 parts by mass.

Production Example 7
100 parts by mass of the polymer 1 [(meth) acrylic resin] obtained in Synthesis Example 1, 11 parts by mass of a polyfunctional isocyanate compound [manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200], and normal butyl acetate 37 Adhesive 7 was obtained by sufficiently stirring and mixing the mass parts.

Examples 1 to 6 and Comparative Example 1 [Preparation of Back Sheet for Solar Cell Module]
Using any one of the adhesives 1 to 7, the adhesive is applied to the substrate 1 so that the coating amount after drying is 3 g / m ^2, and is dried at 100 ° C. for 2 minutes, thereby bonding. An agent layer was formed. Thereafter, using the base material 1 on which the adhesive layer is formed, the base 1 to the base 3 in order from the filler (EVA sheet described later) side, the surface on which the adhesive layer of the base 1 is not formed. A laminate is manufactured by laminating by a dry laminating method so that the base material 1 / adhesive X / base material 2 / adhesive agent X / base material 3 are laminated with the adhesive X. The laminated body was cured at 50 ° C. for 5 days to produce a solar cell module backsheet.

As the adhesive X, a main component of a polyester-based adhesive (manufactured by Dainippon Ink and Chemicals, product number: LX703VL) and a polyisocyanate curing agent (manufactured by Dainippon Ink and Chemicals, product number: KE90). The coating amount after drying of the adhesive X was adjusted to 10 g / m ² .

  Next, the physical properties of the solar cell module backsheet obtained above were examined by the following methods. The results are shown in Table 1.

[Blocking properties]
The back sheet for a solar cell module is cut into a width of 5 cm and a length of 20 cm, the surface on which the adhesive layer surface of the cut sheet is formed, and an untreated heat-resistant oligomer PET film [trade name: Lumirror X10S] is placed on a laminate obtained by superimposing a weight of 5 kg, and the laminate is placed in an oven at a temperature of 40 ° C. and held for 24 hours, and then the laminate is removed from the oven. The adhesive layer was visually observed and the blocking property was evaluated based on the following evaluation criteria.

(Evaluation criteria)
○: Adhesive layer is not transferred to untreated PET film (pass)
X: The adhesive layer is transferred to an untreated PET film (failed)

[Initial adhesion]
Evaluation was made by a cross-cut method based on JIS K5600-5-6 using a solar cell module backsheet.

〔Adhesiveness〕
One sheet of solar cell module backsheet cut to a width of 60 mm and a length of 200 mm and an EVA sheet (manufactured by Mitsui Chemicals Fabro, product number: RC02B, thickness: 400 μm) are cut to a width of 60 mm and a length of 90 mm And a tempered glass plate (width 100 mm, length 100 mm, thickness 3 mm) were prepared.

  The laminated body was obtained by superposing | stacking in order of the back sheet | seat for solar cell modules / EVA sheet | seat / tempered glass board so that the surface which evaluates the adhesiveness of the back sheet | seat for solar cell modules may contact | connect an EVA sheet | seat.

Next, the obtained laminate was sandwiched between fluororesin sheets (manufactured by DuPont, Teflon (registered trademark) sheet) and evacuated for 3 minutes at a temperature of 150 ° C. under a pressure of 5 N / cm ² , and 150 ° C. A sample was prepared by storing in a heated oven for 8 minutes and allowing the crosslinking reaction to proceed.

  In an atmosphere with a relative humidity of 65% at 23 ° C., the tempered glass plate and EVA sheet of the unbonded part of the sample obtained above were sandwiched between upper and lower clips of Autograph (manufactured by Shimadzu Corporation), respectively. The peel strength (initial value) at a crosshead speed of 300 mm / min with a width of 25 mm was measured by a 180 degree peel method, and evaluated based on the following evaluation criteria.

  Furthermore, after leaving a sample different from the sample whose peel strength was measured in an atmosphere of 85 ° C. and a relative humidity of 85% for 1000 hours or 2000 hours, the peel strength was measured under the same conditions as described above, and the following evaluation was performed. Adhesion was evaluated based on criteria.

(Evaluation criteria)
A: Peel strength is 40 N / 10 mm or more (very good adhesion)
B: Peel strength is 20 N / 10 mm or more and less than 40 N / 10 mm (excellent adhesiveness)
C: Peel strength is 10 N / 10 mm or more and less than 20 N / 10 mm (good adhesiveness)
D: Peel strength is less than 10 N / 10 mm (adhesion is poor) (failed)

  From the results shown in Table 1, the back sheet for the solar cell module obtained in each example is less likely to cause blocking than the back sheet for the solar cell module obtained in Comparative Example 1, and has an initial adhesion. It is a case where an accelerated test (humidity heat resistance test) in a high-temperature and high-humidity atmosphere examined when evaluating a solar cell module as well as the environment actually used as a solar cell. It is also found that the adhesiveness to the filler is excellent.

  From the above, it can be seen that any of the solar cell module backsheets obtained in each example can be suitably used for solar cell modules and solar cells.

  The solar cell module backsheet of the present invention is less susceptible to blocking, has excellent initial substrate adhesion, and has been studied when evaluating solar cell modules as well as environments actually used as solar cells. Even when an accelerated test (humidity heat resistance test) is performed in a high-temperature and high-humidity atmosphere, it is excellent in adhesiveness to the filler, and thus can be suitably used for solar cell modules and solar cells.

1: Base material 2: Adhesive 3: Barrier layer 4: Adhesive layer

Claims (5)

  An adhesive for a solar cell module, which is an adhesive used for laminating a back sheet and a filler used in a solar cell module, and contains a thermoplastic resin, a curing agent, and plate-like particles.   The adhesive for solar cell modules according to claim 1, wherein the curing agent is at least one selected from the group consisting of (block) polyisocyanate compounds, epoxy resins and oxazoline group-containing resins.   It is a back sheet used for a solar cell module, and an adhesive layer made of the adhesive for solar cell module according to claim 1 or 2 is formed on a surface bonded to a filler constituting the solar cell module. A back sheet for a solar cell module.   A solar cell module comprising the back sheet for a solar cell module according to claim 3.   A solar cell comprising the solar cell module according to claim 4.

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