JP2012149211A - Back sheet for solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive for solar cell module, which has excellent adhesiveness to a filler used for a solar cell and weather-resistance, maintains electric output characteristics, and hardly causes an appearance failure of a back sheet when subjected to accelerating tests not only in an environment actually used as the solar cell but also in a high-temperature, high-humidity atmosphere to be examined in evaluation of a solar cell module; a back sheet for solar cell module; a solar cell module; and a solar cell.SOLUTION: The adhesive for solar cell module to be used to adhere a back sheet used in a solar cell module to a filler contains a polymer having a ring structure including hetero atom in a main chain, the polymer being obtained by cyclopolymerizing a monomer component containing at least one diene structure-containing monomer selected from the group consisting of 1,5-diene structure-containing monomer including hetero atom and 1,6-diene structure-containing monomer including hetero atom.

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%. Has been done.

  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 Patent Document 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 for the back sheet for the solar cell module and EVA used as the filler are excellent in adhesiveness during the production of the solar cell, but the adhesiveness decreases with the passage of time. There are drawbacks.

  Therefore, in recent years, it is used not only in an environment actually used as a solar cell but also in a solar cell even when an accelerated test is performed in a high-temperature and high-humidity atmosphere studied when evaluating a solar cell module. It is desired to develop a back sheet for a solar cell module that is excellent in adhesiveness and weather resistance to a filler, maintains electric output characteristics, and is unlikely to cause poor appearance of the back 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 2002-26354 A

  The present invention has been made in view of the above-described prior art, and not only an 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 a solar cell module. Adhesive for solar cell module that is excellent in adhesion and weather resistance to fillers used in solar cells, maintains electric output characteristics, and does not easily cause poor appearance of the back sheet It aims at providing the solar cell module backsheet in which the adhesive bond layer which consists of an adhesive agent for modules was formed, the solar cell module which has this backsheet for solar cell modules, and a solar cell.

The present invention
(1) An adhesive used for laminating a back sheet and a filler used in a solar cell module, which includes a 1,5-diene structure-containing monomer containing a hetero atom and a 1,6-containing hetero atom Polymer having in its main chain a ring structure containing a heteroatom obtained by cyclopolymerizing a monomer component containing at least one diene structure-containing monomer selected from the group consisting of diene structure-containing monomers An adhesive for solar cell modules, comprising:
(2) The polymer is of 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, and at least one of X, Y and Z is an oxygen atom, a sulfur atom or an imino group not adjacent to each other)
The adhesive for solar cell modules according to (1), having a ring structure-containing unit represented by:
(3) Furthermore, the adhesive for solar cell modules according to (1) or (2), further containing a curing agent,
(4) The adhesive for solar cell modules according to (3), wherein the curing agent is at least one selected from the group consisting of (block) polyisocyanate compounds, epoxy resins, and oxazoline group-containing resins,
(5) It is a back sheet used for a solar cell module, Comprising: On the surface bonded with the filler which comprises a solar cell module, The adhesive for solar cell modules in any one of said (1)-(4) A back sheet for a solar cell module, characterized in that an adhesive layer comprising:
(6) A solar cell module comprising the back sheet for a solar cell module according to (5), and (7) a solar cell comprising the solar cell module according to (6). About.

  The adhesive for a solar cell module of the present invention is a case where 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 considered when evaluating the solar cell module. In addition, it has excellent adhesion and weather resistance to the filler used in the solar cell, maintains the electric output characteristics, and has an excellent effect that the appearance failure of the back sheet is difficult to occur.

  The solar cell module backsheet of the present invention is formed with an adhesive layer made of the solar cell module adhesive. Therefore, when evaluating the solar cell module as well as the environment actually used as the solar cell. Even when an accelerated test is performed in a high-temperature and high-humidity atmosphere, the adhesion and weather resistance to the filler used in solar cells are excellent, the electric output characteristics are maintained, and the appearance of the back sheet is poor. There is an excellent effect that it is difficult to occur.

  Since the solar cell module and the solar cell of the present invention have the back sheet for the solar cell module, not only the environment actually used as a solar cell but also a high-temperature and high-humidity atmosphere considered when evaluating the solar cell module Even when an accelerated test is performed, it has excellent adhesion and weather resistance to fillers used in solar cells, maintains electrical output characteristics, and does not easily cause poor appearance of the backsheet. Play.

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.

  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 1,5-diene structure-containing monomer containing a hetero atom and a hetero Containing a heteroatom obtained by cyclopolymerizing a monomer component containing at least one diene structure-containing monomer selected from the group consisting of 1,6-diene structure-containing monomers containing atoms It contains a polymer having a ring structure in the main chain.

  Since the adhesive for solar cell modules of the present invention contains a polymer having a ring structure containing a hetero atom in the main chain, when evaluating a solar cell module as well as an environment actually used as a solar cell. Even when an accelerated test is performed in a high-temperature and high-humidity atmosphere, the adhesion and weather resistance to the filler used in solar cells are excellent, the electric output characteristics are maintained, and the appearance of the back sheet is poor. It has an excellent property that it is difficult to occur.

  The polymer having a ring structure containing a heteroatom in the main chain performs 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 considered when evaluating a solar cell module. From the viewpoint of producing an adhesive for a solar cell module that is excellent in adhesion and weather resistance to fillers used in solar cells, maintains electrical output characteristics, and does not easily cause poor appearance of the backsheet. , 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)
It is preferable to have a ring structure-containing unit represented by

In the formula (I), 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.

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 above-mentioned “oxygen atom, sulfur atom or imino group not adjacent to each other” means that heteroatoms are not adjacent to each other, for example, —O—O—, —O—NR ⁷ — and the like.

  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 these, from the viewpoint of improving the cyclopolymerization activity, the heat resistance of the resulting polymer and the transparency of the adhesive, the 1,6-diene structure-containing monomer represented by the formula (IIa), the formula (IIb) 1,6-diene structure-containing monomer represented by formula (II) and a 1,6-diene structure-containing monomer represented by formula (IIc) are preferred, from the viewpoint of improving the adhesion to fillers used in solar cells. A 1,6-diene structure-containing monomer represented by the 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, not only the environment actually used as a solar cell, but also a case where an accelerated test is performed in a high-temperature and high-humidity atmosphere studied when evaluating a solar cell module is used for a solar cell. From the viewpoint of excellent adhesion and weather resistance to the resulting filler, maintaining electrical output characteristics, and making it difficult to cause poor appearance of the backsheet, methyl α-allyloxymethyl acrylate, ethyl α-allyloxymethyl acrylate, Preferred are 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, not only the environment actually used as a solar cell, but also a case where an accelerated test is performed in a high-temperature and high-humidity atmosphere studied when evaluating a solar cell module is used for a solar cell. Α-methallyloxymethyl acrylate, α-methallyloxymethylacrylic acid from the viewpoint of excellent adhesion and weather resistance to the filler used, maintaining electrical output characteristics, and reducing the appearance of the back sheet Ethyl, 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, not only the environment actually used as a solar cell, but also a case where an accelerated test is performed in a high-temperature and high-humidity atmosphere studied when evaluating a solar cell module is used for a solar cell. Bis (α-hydroxymethylacrylic acid) ether and bis (α-hydroxymethylacrylic) from the viewpoint of excellent adhesion and weather resistance to the fillers, maintaining electrical output characteristics, and making it difficult to cause poor appearance of the backsheet Acid methyl) 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 polymer having a ring structure containing a heteroatom in the main chain is preferably 5% by mass or more from the viewpoint of hardly causing a bad appearance of the backsheet. More preferably 10% by mass or more, further preferably 15% by mass or more, and 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 considered when evaluating a solar cell module Even if it is performed, from the viewpoint of excellent adhesion and weather resistance to the filler used in solar cells, maintaining electrical output characteristics, and less likely to cause poor appearance of the backsheet, 100% by mass or less, Preferably it is 99 mass% or less, More preferably, it is 95 mass% or less, More preferably, it is 90 mass% or less.

  The content of the ring structure-containing unit represented by the formula (I) in the polymer having a ring structure containing a hetero atom in the main chain is used as a raw material for the polymer having a ring structure containing a hetero atom in the main chain. It is determined as the content of the diene structure-containing monomer that gives the ring structure-containing unit represented by the formula (I) in the monomer component.

  The content of the monomer containing the diene structure in the monomer component is determined not only in the environment where it is actually used as a solar cell, but also in a high-temperature and high-humidity atmosphere that is considered when evaluating solar cell modules. Even from the viewpoint of excellent adhesion and weather resistance to the filler used in the solar cell, maintaining electrical output characteristics, and less likely to cause poor appearance of the backsheet, preferably 5% by mass or more, More preferably 10% by mass or more, further preferably 15% by mass or more, and 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 considered when evaluating a solar cell module Even if it is performed, it has excellent adhesion and weather resistance to fillers used in solar cells, maintains electrical output characteristics, and From the viewpoint of Gataku cause defects, 100 wt% or less, preferably 99 wt% or less, more preferably 95 wt% or less, more preferably not more than 90 wt%.

  The polymer may contain a unit other than the unit having a ring structure containing a hetero atom within a 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; cyclohexyl methyl acrylate, cyclohexyl methyl methacrylate Cycloalkylethyl (meth) acrylates such as cyclohexylethyl acrylate, cyclohexylethyl methacrylate, cyclohexylpropyl acrylate, cyclohexylpropyl methacrylate, 4-methylcyclohexylmethyl acrylate, 4-methylcyclohexylmethyl methacrylate, and the like. However, the present invention is not limited to such examples. 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. However, 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) acrylamides such as acrylamide and methacrylamide, N, N′-dimethylaminoethyl acrylate, N, N′-dimethylaminoethyl methacrylate, and N, N-diethylaminoethyl acrylate. , N, N-diethylaminoethyl methacrylate, nitrogen atom-containing (meth) acrylates such as imide acrylate, imide methacrylate and the like, 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. Examples include dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, and the like, but the present invention is not limited to such examples. 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 the diene structure-containing monomer, not only the 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 solar cell modules. Even if it is a case, from a viewpoint of improving the adhesiveness with respect to the filler used for a solar cell, the property which provides weather resistance, such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, and tert- butyl (meth) acrylate, Monomers containing monomers (hereinafter referred to as weather resistant monomers), hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate and caprolactone-modified (meth) acrylate are preferred.

  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 from the viewpoint of improving the brittleness of the adhesive, it is 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% by mass or less. is there.

  From the viewpoint of improving the durability of the adhesive, 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, and even more preferably 1% by mass. From the viewpoint of improving hydrolysis resistance and insulation resistance, it is preferably 40% by mass or less, more preferably 35% by mass or less.

  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. ) acrylates, may also tricyclo [5,2,1,0 ^2.6] dec-8-yl (meth) acrylate and terpene-based (meth) the use of such acrylate.

  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 the 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 polymer, etc., and is not particularly limited, but the weight average molecular weight is several thousand to When obtaining tens of thousands of polymers, the amount is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass per 100 parts by mass of the monomer component.

  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, butyl acetate, cellosolve acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol; amide solvents such as dimethylformamide However, the present invention is not limited to such examples. 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 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 polymer to be obtained, but is usually preferably 0.01 to 50 parts by mass, more preferably 100 parts by mass of the monomer component. 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.

  A polymer is obtained by polymerizing the monomer component as described above. The weight average molecular weight of the polymer 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.

  In addition, the hydroxyl value of the polymer (non-volatile content) is not only the environment actually used as a solar cell, but also when performing an accelerated test in a high-temperature and high-humidity atmosphere that is considered when evaluating solar cell modules. Even if it exists, from a viewpoint of improving the adhesiveness with respect to the filler used for a solar cell, Preferably it is 0.4-200 mgKOH / g.

  Adhesives for solar cell modules can be used not only in the environment where they are actually used as solar cells, but also in the case of performing accelerated tests in high-temperature and high-humidity atmospheres that are considered when evaluating solar cell modules. The polymer is contained from the viewpoints of excellent adhesion and weather resistance to the filler used in the battery, maintaining electrical output characteristics, and preventing the appearance of the back sheet from being poor.

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

  The content of polymer in the nonvolatile content contained in the adhesive for solar cell modules is accelerated not only in the environment where they are actually used as solar cells, but also in hot and humid atmospheres that are considered when evaluating solar cell modules. Even when the test is performed, 40 masses is preferable from the viewpoint of excellent adhesion and weather resistance to the filler used in the solar cell, maintaining electric output characteristics, and less likely to cause poor appearance of the backsheet. % Or more, more preferably 45% by mass or more. The non-volatile content of the adhesive for solar cell modules may be composed of a polymer only.

  The adhesive layer made of the solar cell module adhesive 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, and the solar cell module adhesive contains a curing agent, and the solar cell module adhesive is added with the curing agent. It may be formed by crosslinking.

  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. In addition, the block polyisocyanate compound is not only used in an environment actually used as a solar cell, but also in a case where an accelerated test is performed in a high-temperature and high-humidity atmosphere studied when evaluating a solar cell module. Excellent adhesion to fillers used in batteries. 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 names: Duranate E-402-90T, Duranate TPA-B80E, Duranate MF-B60X, Duranate MF-K60X, etc. can be easily obtained commercially.

  The amount of the (block) polyisocyanate compound is not particularly limited. For example, the amount of the isocyanate group in the (block) polyisocyanate compound per 1 mol of hydroxyl group in the polymer is preferably 0.6 mol or more from the viewpoint of improving the hydrolysis resistance and insulation resistance of the adhesive layer. More preferably, it is 0.8 mol or more, and preferably 1.4 mol or less from the viewpoint of preventing the unreacted isocyanate group from reacting with moisture in the air to foam or whiten the adhesive layer. More preferably, it is 1.2 mol or less.

  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 of the polymer to the aminoplast resin (polymer / 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 enhancing the hydrolysis resistance and adhesion of the layer, the ratio is preferably 9/1 or less.

  Since the amount of the curing agent varies depending on the type of the curing agent and the like, it cannot be determined unconditionally, but usually from the viewpoint of hydrolysis resistance and insulation resistance of the adhesive layer with respect to 100 parts by mass of the polymer. , Preferably 1 part by mass or more, more preferably 3 parts by mass or more, and preferably 60 parts by mass or less, more preferably 50 parts by mass or less, from the viewpoint of improving the adhesion to the filler used in the solar cell. Preferably it is 30 mass parts or less. For example, when the polymer has a plurality of hydroxyl groups in one molecule, the amount of the curing agent may be appropriately adjusted according to the number of hydroxyl groups that the polymer has.

  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 the polymer has a plurality of hydroxyl groups in one molecule, a curing agent addition method or a dispersion method may be selected according to the type of the polymer.

  The solar cell module adhesive may contain a curing catalyst for promoting the crosslinking reaction between the polymer and the curing agent, if necessary. Although there is no limitation in particular as a curing catalyst, For example, when using a (block) polyisocyanate compound, dibutyltin dilaurate, a tertiary amine, etc. are preferable. Further, when an aminoplast resin is used, an acidic or basic curing catalyst is preferable.

  The solar cell module adhesive may contain a solvent, an additive, or 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; inorganic fine particles such as colloidal silica and alumina sol; organic fine particles based on polymethyl methacrylate; antifoaming agents; sagging inhibitors; silane coupling agents; titanium white, composite oxide pigments, Pigments such as carbon black, organic pigments and pigment intermediates; pigment dispersants; antioxidants such as phosphorus antioxidants and phenolic antioxidants; viscosity modifiers; UV stabilizers; metal deactivators; Flame retardants; Reinforcing agents; Plasticizers; Lubricants; Rust inhibitors; Fluorescent brighteners; Organic and inorganic UV absorbers, inorganic heat absorbers; 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.

  Note that the amounts of the curing catalyst, the solvent, and the additive vary depending on the type of the curing catalyst, and cannot be determined unconditionally. Therefore, it is preferable to appropriately adjust according to the properties required for the adhesive layer.

  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., Byron (registered trademark) 103, 240, 500, GK110, GK640, etc .; Nippon Synthetic Chemical Industry Co., Ltd., Nichigo Polyester (registered trademark) TP- 220, TP-235, TP-236, TP-290, and the like are included, but the present invention is not limited to such examples.

  Examples of the modified olefin resin include Nippon Paper Chemicals Co., Ltd., Aurolen (registered trademark) 100, 200, 350, S-5189, etc .; Sanyo Chemical Industries, Ltd., Umex 1001, 1010, 2000, and the like. Although mentioned, this invention is not limited only to this illustration.

  Examples of the EVA include Tosoh Corporation, Mersen (registered trademark) H-6051, H-6410, and the like; Sumitomo Chemical Co., Ltd., Sumitate (registered trademark) KA-31, KA-42, and the like. However, the present invention is not limited to such examples.

  Examples of the polyvinyl butyral (PVB) include Kuraray Co., Ltd., Mowital (registered trademark) series B30H, B45M, and B60H. However, the present invention is not limited to such examples.

  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 Yashara Chemical Co., Ltd., Clearon (registered trademark) M-115, P-115 and the like, but the present invention is not limited to such examples. .

  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, but is preferably 3 parts by mass from the viewpoint of improving the adhesion to the adherend per 100 parts by mass of the polymer. As mentioned above, More preferably, it is 5 mass parts or more, From a viewpoint of suppressing the fall of adhesive force, Preferably it is 200 mass parts or less, More preferably, it is 150 mass parts or less.

  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 containing a polymer formed on the surface to be bonded to the filler constituting the solar cell module Is preferably 0.1 μm or more, more preferably 0.3 μm or more, further preferably 1 μm or more from the viewpoint of adhesion and weather resistance, and preferably 50 μm or less, more preferably 30 μm from the viewpoint of preventing embrittlement. Hereinafter, it is more preferably 20 μm or less.

  FIG. 1 is a schematic cross-sectional view showing a configuration when the base material is bonded with an 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 is performed in a high-temperature and high-humidity atmosphere, the adhesion and weather resistance to fillers used in solar cells are maintained, and the electrical output characteristics are maintained, and the appearance of the back sheet There is an excellent effect that it is difficult for defects to occur.

  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. Adhesion comprising a solar cell module adhesive containing a polymer on the surface bonded to the filler constituting the solar cell module by interposing a barrier layer 3 such as a gas barrier layer on By forming the agent layer, a solar cell module backsheet is formed. 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 an accelerated test is performed in a high-temperature and high-humidity atmosphere, which is considered when evaluating, excellent adhesion and weather resistance to fillers used in solar cells, maintaining electrical output characteristics, An excellent effect is obtained that it is difficult for appearance defects to occur.

  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. Examples of the metal vapor deposition film include an aluminum vapor deposition film obtained by vapor-depositing aluminum on a polyester film or a polyolefin-based stretched film.

  Examples of the oxide vapor deposition film include a film obtained by vapor-depositing aluminum oxide, silicon dioxide, tin oxide, magnesium oxide, indium oxide, and a composite oxide thereof on a polyester film, which is transparent and includes oxygen gas, water vapor, and the like. 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, it is 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 a method for forming an oxide deposition layer on a film include a vacuum 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 if it performs, it has the outstanding effect that it is excellent in the adhesiveness and weather resistance with respect to the filler used for a solar cell, maintains an electrical output characteristic, and does not produce the appearance defect of a back sheet easily.

  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>
Product name: Tetoron U298W [white polyethylene terephthalate (hereinafter referred to as PET) film] manufactured by Teijin DuPont Films Ltd.
<Substrate 2>
Product name: Tech barrier (silicon dioxide-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: RC02B (EVA sheet having a thickness of 400 μm), manufactured by Mitsui Chemicals Fabro Co., Ltd.

Synthesis example 1
As a reaction vessel, a 500 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, 76.8 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 consisting of 98.5 g of methyl α-allyloxymethyl acrylate and 1.5 g of 2-hydroxyethyl methacrylate is placed in dropping tank A, and 2,2′- as a polymerization initiator is added in dropping tank B. A mixture of 0.53 g azobis (2,4-dimethylvaleronitrile), 0.32 g n-dodecyl mercaptan and 23.1 g ethyl acetate was added.

  After confirming that the internal temperature of the reaction tank was stable, the dropping of the monomer component in the dropping tank A and the mixture in the dropping tank B was started at the same time, while adjusting the internal temperature to 60 to 63 ° C. From tank A, the monomer component was dropped over 3 hours, and from drop tank B, the mixture was dropped over 4 hours. After completion of the dropwise addition, the internal temperature of the reaction vessel is increased to 78 to 80 ° C., and the contents of the reaction vessel are heated for 2 hours with stirring, and then cooled to room temperature, whereby a polymer having a nonvolatile content of 50.0% by mass. Solution was obtained. The weight average molecular weight of the obtained polymer (hereinafter referred to as polymer 1) was 55000, and the hydroxyl value of polymer 1 (nonvolatile content) was 6 mgKOH / g.

Synthesis example 2
In Synthesis Example 1, the composition of the monomer component was changed to 95 g of α-allyloxymethyl acrylate and 5 g of 2-hydroxyethyl methacrylate, and the nonvolatile content was 50.0 mass by the same method as Synthesis Example 1. % Polymer solution. The obtained polymer (hereinafter referred to as polymer 2) had a weight average molecular weight of 52,000, and polymer 2 (nonvolatile content) had a hydroxyl value of 22 mgKOH / g.

Synthesis example 3
In Synthesis Example 1, the composition of the monomer component was changed to 70 g of methyl α-allyloxymethyl acrylate and 30 g of 2-hydroxyethyl methacrylate, and the nonvolatile content was 49.9 mass by the same method as Synthesis Example 1. % Polymer solution. The obtained polymer (hereinafter referred to as polymer 3) had a weight average molecular weight of 52,000, and polymer 3 (nonvolatile component) had a hydroxyl value of 130 mgKOH / g.

Synthesis example 4
In Synthesis Example 1, the composition of the monomer component was changed to 68 g of methyl α-allyloxymethyl acrylate, 20 g of cyclohexyl methacrylate, 5 g of n-butyl acrylate, 5 g of 2-hydroxyethyl methacrylate, and a monomer having a UV-stable group [( Made by ADEKA, trade name: ADK STAB LA-82] A polymer solution having a nonvolatile content of 49.9% by mass was obtained in the same manner as in Synthesis Example 1 except that the amount was changed to 2 g. The weight average molecular weight of the obtained polymer (hereinafter referred to as polymer 4) was 47000, and the hydroxyl value of polymer 4 (nonvolatile content) was 22 mgKOH / g.

Synthesis example 5
In Synthesis Example 1, the composition of the monomer component is 48 g of methyl α-allyloxymethyl acrylate, 40 g of cyclohexyl methacrylate, 5 g of n-butyl acrylate, 5 g of 2-hydroxyethyl methacrylate, and a monomer having an ultraviolet-stable group [( Made by ADEKA, trade name: ADK STAB LA-82] A polymer solution having a nonvolatile content of 49.8% by mass was obtained in the same manner as in Synthesis Example 1 except that the amount was changed to 2 g. The weight average molecular weight of the obtained polymer (hereinafter referred to as polymer 5) was 45000, and the hydroxyl value of polymer 5 (nonvolatile content) was 22 mgKOH / g.

Synthesis Example 6
In Synthesis Example 1, the composition of the monomer component is 53 g of methyl α-allyloxymethyl acrylate, 20 g of cyclohexyl methacrylate, 5 g of 2-hydroxyethyl methacrylate, and 2- (2′-hydroxy as a monomer having an ultraviolet absorbing group. -5′-methacryloyloxyethylphenyl) -2H-benzotriazole [manufactured by Otsuka Chemical Co., Ltd., trade name: RUVA93] and a monomer having an ultraviolet light-stable group [manufactured by ADEKA, trade name: ADK STAB LA -82] A polymer solution having a nonvolatile content of 50.0% by mass was obtained in the same manner as in Synthesis Example 1 except that the amount was changed to 2 g. The weight average molecular weight of the obtained polymer (hereinafter referred to as polymer 6) was 47000, and the hydroxyl value of polymer 6 (nonvolatile content) was 22 mgKOH / g.

Synthesis example 7
In Synthesis Example 1, the composition of the monomer component was 67 g of methyl α-allyloxymethyl acrylate, 20 g of tert-butyl methacrylate, 4 g of n-butyl acrylate, and caprolactone-modified hydroxy methacrylate as a hydroxyl group-containing monomer [Daicel Chemical Industries, Ltd. Product name: Plaxel FM1] A polymer solution having a nonvolatile content of 50.1% by mass was obtained in the same manner as in Synthesis Example 1 except that the product was changed to 9 g. The weight average molecular weight of the obtained polymer (hereinafter referred to as polymer 7) was 48000, and the hydroxyl value of polymer 7 (nonvolatile content) was 21 mgKOH / g.

Synthesis Example 8
In a 500 milliliter flask equipped with a stirrer, a dripping port, a thermometer, a cooling pipe and a nitrogen gas inlet, 60 g of ethyl acetate was charged and refluxed at about 80 ° C. In this flask, a mixture of 90 g of methyl methacrylate, 10 g of 2-hydroxyethyl methacrylate, 0.35 g of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator and 15 g of ethyl acetate was taken over 2 hours. It was dripped continuously in the flask. Furthermore, 0.1 hour of 2,2′-azobis (2,4-dimethylvaleronitrile) was added as a polymerization initiator after 1 hour and 1 hour and a half from the end of dropping, and after heating for another hour and a half. By adding 25 g of ethyl acetate, an acrylic polymer solution having a nonvolatile content of 49.9% by mass was obtained. The obtained acrylic polymer (hereinafter referred to as polymer 8) had a weight average molecular weight of 50,000, and polymer 8 (nonvolatile content) had a hydroxyl value of 43 mgKOH / g.

Synthesis Example 9
In Synthesis Example 1, the composition of the monomer component was changed to 78 g of methyl α-allyloxymethyl acrylate, 13 g of isobornyl methacrylate, and 9 g of 2-hydroxyethyl methacrylate, and nonvolatile in the same manner as in Synthesis Example 1. A polymer solution having an amount of 49.3% by mass was obtained. The weight average molecular weight of the obtained polymer (hereinafter referred to as polymer 9) was 72000, and the hydroxyl value of polymer 9 (nonvolatile content) was 39 mgKOH / g.

Synthesis Example 10
In Synthesis Example 1, the composition of the monomer component was changed to 66 g of methyl α-allyloxymethyl acrylate, 25 g of isobornyl methacrylate, and 9 g of 2-hydroxyethyl methacrylate, and nonvolatile in the same manner as in Synthesis Example 1. A polymer solution having an amount of 49.0% by mass was obtained. The weight average molecular weight of the obtained polymer (hereinafter referred to as polymer 10) was 64000, and the hydroxyl value of polymer 10 (nonvolatile content) was 39 mgKOH / g.

Production Example 1
At a ratio of 1 part by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) with respect to 100 parts by mass (non-volatile content) of the polymer 1 (polymer) obtained in Synthesis Example 1. Then, polymer 1 and polyisocyanate curing agent were put in a container, and further diluted with ethyl acetate until the nonvolatile content concentration became 10% by mass to obtain adhesive 1.

Production Example 2
In a ratio of 4 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) with respect to 100 parts by mass (nonvolatile content) of the polymer 2 (polymer) obtained in Synthesis Example 2. The polymer 2 and the polyisocyanate curing agent were put in a container, and further diluted with ethyl acetate until the nonvolatile content concentration became 10% by mass, whereby an adhesive 2 was obtained.

Production Example 3
In a ratio of 26 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) with respect to 100 parts by mass (non-volatile content) of polymer 3 (polymer) obtained in Synthesis Example 3. The polymer 3 and the polyisocyanate curing agent were put in a container, and further diluted with ethyl acetate until the nonvolatile content concentration became 10% by mass to obtain an adhesive 3.

Production Example 4
At a ratio of 4 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) with respect to 100 parts by mass (non-volatile content) of the polymer 4 (polymer) obtained in Synthesis Example 4. Then, the polymer 4 and the polyisocyanate curing agent were put in a container, and further diluted with ethyl acetate until the nonvolatile content concentration became 10% by mass to obtain an adhesive 4.

Production Example 5
At a ratio of 4 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) with respect to 100 parts by mass (non-volatile content) of polymer 5 (polymer) obtained in Synthesis Example 5. Then, the polymer 5 and the polyisocyanate curing agent were put in a container, and further diluted with ethyl acetate until the nonvolatile content concentration became 10% by mass to obtain an adhesive 5.

Production Example 6
At a ratio of 4 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) with respect to 100 parts by mass (non-volatile content) of the polymer 6 (polymer) obtained in Synthesis Example 6. Then, the polymer 6 and the polyisocyanate curing agent were put in a container, and further diluted with ethyl acetate until the nonvolatile content concentration became 10% by mass to obtain an adhesive 6.

Production Example 7
At a ratio of 4 parts by mass of polyisocyanate curing agent [manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200] with respect to 100 parts by mass (non-volatile content) of polymer 7 (polymer) obtained in Synthesis Example 7. Then, the polymer 7 and the polyisocyanate curing agent were put in a container, and further diluted with ethyl acetate until the nonvolatile content concentration became 10% by mass to obtain an adhesive 7.

Production Example 8
The adhesive 8 was obtained by diluting the polymer 2 (polymer) obtained in Synthesis Example 2 with ethyl acetate until the nonvolatile content concentration became 10% by mass.

Production Example 9
In a ratio of 7 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) with respect to 100 parts by mass (non-volatile content) of the polymer 9 (polymer) obtained in Synthesis Example 9. The polymer 9 and the polyisocyanate curing agent were put in a container, and further diluted with ethyl acetate until the nonvolatile content concentration became 10% by mass to obtain an adhesive 9.

Production Example 10
At a ratio of 7 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) with respect to 100 parts by mass (non-volatile content) of the polymer 10 (polymer) obtained in Synthesis Example 10. Then, the polymer 10 and the polyisocyanate curing agent were placed in a container, and further diluted with ethyl acetate until the nonvolatile content concentration became 10% by mass to obtain an adhesive 10.

Production Example 11
8 parts by mass of polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) with respect to 100 parts by mass (nonvolatile content) of polymer 8 (acrylic polymer) obtained in Synthesis Example 8 By the ratio, the polymer 8 and the polyisocyanate curing agent were put in a container, and further diluted with ethyl acetate until the nonvolatile content concentration became 10% by mass to obtain an adhesive 11.

Examples 1 to 10 [Preparation of Back Sheet for Solar Cell Module]
As shown in Table 1, any one of the adhesives 1 to 10 was used, and the adhesive was applied to the base material 1 so that the coating amount after drying was 1 g / m ^2, and at 100 ° C. for 1 minute. By drying, an adhesive layer was formed. Then, using this base material as the base material 1, the surface on which the adhesive layer of the base material 1 is not formed is the adhesive X in order from the base material 1 to the base material 3 from the filler (EVA sheet described later) side. A laminated body is manufactured by laminating by a dry laminating method so that the base material 1 / adhesive X / base material 2 / adhesive X / base material 3 are laminated. A solar cell module backsheet was prepared by curing at 50 ° C. for 5 days.

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). Used, and adjusted so that the coating amount after drying of the adhesive X was 10 g / m ² .

Comparative Example 1
A back sheet for a solar cell module was produced in the same manner as in Example 1 except that the adhesive 11 was used instead of the adhesive 1 in Example 1.

Comparative Example 2
A back sheet for a solar cell module was produced in the same manner as in Example 1 except that the adhesive 1 was not used in Example 1.

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

[Blocking properties]
The back sheet for a solar cell module obtained in each example or each comparative example was 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 was formed, and an untreated heat-resistant oligomer PET film [Toray Co., Ltd., trade name: Lumirror X10S] is stacked on a laminate obtained by superimposing a weight of 5 kg, and this laminate is placed in an oven at a temperature of 40 ° C. for 24 hours. After being held, the laminate was taken out from the oven, the adhesive layer was visually observed, and the blocking property was evaluated based on the following evaluation criteria.

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

〔Adhesiveness〕
Width of one sheet obtained by cutting the back sheet obtained in each example or each comparative example into a width of 60 mm and a length of 200 mm, and an EVA sheet (manufactured by Mitsui Chemicals, Inc., product number: RC02B, thickness: 400 μm) One sheet cut to 60 mm and 90 mm length and a tempered glass plate (width 100 mm, length 100 mm, thickness 3 mm) were prepared.

  The back sheet / EVA sheet / tempered glass plate were laminated in this order so that the surface of the back sheet for solar cell module to be evaluated was in contact with the EVA sheet.

Next, the obtained laminate was evacuated under a pressure of 5 N / cm ² at a temperature of 150 ° C. for 3 minutes, stored in an oven heated to 150 ° C. for 8 minutes, and the crosslinking reaction was allowed to proceed. Was made.

  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. Evaluation was based on criteria.

(Evaluation criteria)
EX: Peel strength of 80 N / 10 mm or more (remarkably excellent adhesion)
A: Peel strength is 40 N / 10 mm or more and less than 80 N / 10 mm (excellent adhesiveness)
B: Peel strength is 20 N / 10 mm or more and less than 40 N / 10 mm (adhesiveness is good)
C: Peel strength is 10 N / 10 mm or more and less than 20 N / 10 mm (adhesiveness is slightly good)
D: Peel strength is less than 10 N / 10 mm (adhesion is poor) (failed)

[Weather resistance, electrical output characteristics and appearance of back sheet]
(1) Weather resistance An A4 size EVA sheet (made by Mitsui Chemicals Fabro Co., Ltd., product number: RC02B, thickness: 400 μm) on the A4 size tempered glass plate as a filler for a solar cell module. After placing solar cells made of polycrystalline silicon sandwiched between, the back sheet obtained in each Example or each Comparative Example is further provided thereon so that the adhesive layer is in contact with the EVA sheet A laminate was obtained. In addition, since the adhesive bond layer was not formed in the back sheet obtained by the comparative example 2, the laminated body was obtained by providing so that the base material 1 may contact | connect an EVA sheet | seat directly.

Thereafter, each laminate obtained above was evacuated under a pressure of 5 N / cm ² at a temperature of 150 ° C. for 3 minutes and then stored in an oven heated to 150 ° C. for 8 minutes to proceed with the crosslinking reaction. I let you. After that, the aluminum frame was used to make a sample.

The sample is irradiated with ultraviolet rays for 100 hours or 150 hours at 100 mW / cm ² at a temperature of 60 ° C. and a relative humidity of 50% using an i-super UV tester (manufactured by Iwasaki Electric Co., Ltd., product number: SUV-W151). Thus, a weather resistance acceleration test was conducted.

Next, the peel strength at a crosshead speed of 300 mm / min was measured by a 180 degree peel method using an autograph (manufactured by Shimadzu Corporation), and the formula:
[Retention rate (%)]
= [(Peel strength after accelerated test) ÷ (Peel strength before accelerated test)] × 100
Based on the above, the retention rate was determined, and the weather resistance was evaluated based on the following evaluation criteria.

(Evaluation criteria)
○: Retention rate is 50% or more (pass)
X: Retention rate is less than 50% (failed)

(2) Electrical output characteristics The maximum output of the sample before and after the weather resistance promotion test was measured according to JIS C8913, and the formula:
[Change rate of maximum output (%)]
= [(Maximum output after accelerated test) / (Maximum output before accelerated test)] x 100
The change rate of the maximum output was obtained based on the above, and the electrical output characteristics were evaluated based on the following evaluation criteria.

(Evaluation criteria)
○: Change rate of maximum output is 95% or more (pass)
Δ: Change rate of maximum output is 90% or more and less than 95% (pass)
×: Change rate of maximum output is less than 90% (failed)

(3) Appearance of Back Sheet The sample was observed visually for the appearance of the back sheet of the sample after the weather resistance promotion test, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
○: No abnormality (pass)
X: There is a float between the EVA sheet and the base material (failed)

  From the results shown in Table 1, not only the back sheet obtained in each example, but also the environment actually used as a solar cell, in contrast to the back sheet obtained in each comparative example, Even when an accelerated test is performed in a high-temperature and high-humidity atmosphere that is considered when evaluating solar cell modules, it has excellent adhesion and weather resistance to fillers used in solar cells and maintains electrical output characteristics. It can be seen that poor appearance of the backsheet hardly occurs.

  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 back sheet for a solar cell module of the present invention is a case where not only the environment actually used as a solar cell but also an accelerated test in a high-temperature and high-humidity atmosphere studied when evaluating the solar cell module. Also, since it has excellent adhesion and weather resistance to fillers used in solar cells, maintains electrical output characteristics, and does not easily cause poor appearance of the backsheet, it can be suitably used for solar cell modules and solar cells. .

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

Claims (7)

  Adhesive used for laminating a backsheet and a filler used in a solar cell module, which includes a 1,5-diene structure-containing monomer containing a heteroatom and a 1,6-diene structure containing a heteroatom Containing a polymer having a ring structure containing a heteroatom in the main chain formed by cyclopolymerizing a monomer component containing at least one diene structure-containing monomer selected from the group consisting of monomers The adhesive for solar cell modules characterized by the above-mentioned. The polymer is of 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, and at least one of X, Y and Z is an oxygen atom, a sulfur atom or an imino group not adjacent to each other)
The adhesive for solar cell modules of Claim 1 which has a ring structure containing unit represented by these.   Furthermore, the adhesive agent for solar cell modules of Claim 1 or 2 containing a hardening | curing agent.   The adhesive for solar cell modules according to claim 3, 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 backsheet used for a solar cell module, Comprising: On the surface bonded with the filler which comprises a solar cell module, the adhesive bond layer which consists of an adhesive agent for solar cell modules in any one of Claims 1-4. A back sheet for a solar cell module, which is formed.   A solar cell module comprising the back sheet for a solar cell module according to claim 5.   A solar cell comprising the solar cell module according to claim 6.