JP2013071947A - (meth)acrylic adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive having excellent blocking resistance, adhesiveness and weatherability, to provide a back sheet for a solar cell module, which has an adhesive layer formed from the adhesive, and to provide the solar cell module and a solar cell.SOLUTION: This (meth)acrylic adhesive includes a (meth)acrylic polymer. The (meth)acrylic polymer has a carbonyl group and a hydrocarbon group adjacent to the carbonyl group. The back sheet for a solar cell module has an adhesive layer formed from the adhesive. The solar cell module and the solar cell are also provided.

Description

  The present invention relates to a (meth) acrylic adhesive. More specifically, the present invention can be suitably used for an adherend containing a polymer in which vinyl carboxylate is used as a monomer, particularly an adherend containing an ethylene-vinyl acetate copolymer. The present invention relates to a possible (meth) acrylic adhesive.

  Conventionally, polymers using vinyl carboxylate as a monomer, especially ethylene-vinyl acetate copolymer, have flexibility and excellent stability to water and ultraviolet rays, and also have rubber elasticity and flexibility. Excellent in toughness, low-temperature properties, weather resistance, transparency, rigidity, friction resistance, electrical insulation, etc., agricultural film, architectural civil engineering sheet, artificial turf, solar cell sealant It is widely used as a material for automobile exterior parts, food wrapping paper, and shoe soles.

  Examples of the material include polyester urethane-based adhesives (for example, see Patent Document 1), polyether urethane-based adhesives (for example, see Patent Document 2), urethane-modified acrylic resin-based adhesives (for example, see Patent Document 3), and the like. The urethane type adhesive is used. However, these adhesives have the disadvantage that they have poor adhesion and are inferior in weather resistance particularly in an environment used outdoors.

  Therefore, in recent years, development of an adhesive having excellent blocking resistance, adhesiveness, and weather resistance has been desired.

JP 2010-043238 A JP 2011-042756 A JP 2011-153204 A

  This invention is made | formed in view of the said prior art, and aims at providing the adhesive agent excellent in blocking resistance, adhesiveness, and a weather resistance. Another object of the present invention is to provide a solar cell module backsheet, a solar cell module, and a solar cell having an adhesive layer made of the adhesive.

The present invention
(1) A (meth) acrylic adhesive containing a (meth) acrylic polymer, wherein the (meth) acrylic polymer has a carbonyl group and a group having a hydrocarbon group adjacent to the carbonyl group. (Meth) acrylic adhesive characterized by being a (meth) acrylic polymer,
(2) The (meth) acrylic adhesive according to (1), wherein the (meth) acrylic polymer has a carbonyl group and a group having a hydrocarbon group adjacent to the carbonyl group in the side chain,
(3) A back sheet for a solar cell module in which an adhesive layer made of the (meth) acrylic adhesive according to (1) or (2) is formed,
(4) A solar cell module comprising the back sheet for a solar cell module according to (3), and (5) a solar cell comprising the solar cell module according to (4). About.

  ADVANTAGE OF THE INVENTION According to this invention, the (meth) acrylic-type adhesive agent excellent in blocking resistance, adhesiveness, and a weather resistance is provided. Since the adhesive layer which consists of the said (meth) acrylic-type adhesive agent is formed in the solar cell module backsheet of this invention, the said adhesive bond layer is excellent in blocking resistance, adhesiveness, and a weather resistance. Further, the solar cell module of the present invention has the solar cell module backsheet, and the solar cell of the present invention has the solar cell module. Excellent blocking, adhesion and weather resistance.

It is a schematic sectional drawing which shows one embodiment of the back sheet | seat for solar cell modules in which the (meth) acrylic-type adhesive agent of this invention was used. It is a schematic sectional drawing which shows another embodiment of the back sheet | seat for solar cell modules in which the (meth) acrylic-type adhesive agent of this invention which has a barrier layer was used.

  As described above, the (meth) acrylic adhesive of the present invention contains a (meth) acrylic polymer, and the (meth) acrylic polymer contains a carbonyl group and a hydrocarbon group adjacent to the carbonyl group. It is a (meth) acrylic polymer having a group having [hereinafter referred to as (meth) acrylic polymer].

  In the present specification, “(meth) acrylic” means acrylic and / or methacrylic, and “(meth) acrylic acid” means acrylic acid and / or methacrylic acid.

  The (meth) acrylic polymer has a group having a carbonyl group and a hydrocarbon group adjacent to the carbonyl group. The group having a carbonyl group and a hydrocarbon group adjacent to the carbonyl group is preferably present in the side chain of the (meth) acrylic polymer from the viewpoint of improving adhesiveness and blocking resistance.

  Examples of the group having a carbonyl group and a hydrocarbon group adjacent to the carbonyl group include those represented by the formula (I):

(Wherein R ¹ represents an alkyl group having 1 to 18 carbon atoms or a hydroxyl group, and R ² represents an alkylene group having 1 to 4 carbon atoms or an aminoalkylene group having 1 to 4 carbon atoms)
A group represented by formula (II):

(Wherein R ¹ and R ² are the same as above)
Group represented by these. Of these carbonyl groups and groups having a hydrocarbon group adjacent to the carbonyl group, a group represented by the formula (II) is preferable.

In the formula (I) and the formula (II), R ¹ is an alkyl group having 1 to 18 carbon atoms or a hydroxyl group, and is preferably an alkyl having 1 to 12 carbon atoms from the viewpoint of improving adhesion and blocking resistance. Group or hydroxyl group, more preferably an alkyl group or hydroxyl group having 1 to 6 carbon atoms, and still more preferably an alkyl group or hydroxyl group having 1 to 4 carbon atoms. Specific examples of suitable alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl groups. Among R ¹ , a methyl group and a hydroxyl group are more preferable from the viewpoint of improving adhesiveness and blocking resistance.

In the formula (I) and the formula (II), R ² is an alkylene group having 1 to 4 carbon atoms or an aminoalkylene group having 1 to 4 carbon atoms. Specific examples of the alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, an isobutylene group, and a tert-butylene group. Examples of the aminoalkylene group having 1 to 4 carbon atoms include formula (III):
—R ³ —NH— (III)
(Wherein R ³ represents an alkylene group having 1 to 4 carbon atoms)
And the like, and the like. Specific examples of R ³ include methylene group, ethylene group, n-propylene group, isopropylene group, n-butylene group, isobutylene group and tert-butylene group.

Among R ² , from the viewpoint of improving adhesion and blocking resistance, in the alkylene group having 1 to 4 carbon atoms and the aminoalkylene group represented by the formula (II), R ³ is alkylene having 1 to 4 carbon atoms. A group which is a group is preferred.

  The (meth) acrylic polymer can be prepared by polymerizing a monomer component containing a monomer having a carbonyl group and a group having a hydrocarbon group adjacent to the carbonyl group.

  Examples of the monomer having a carbonyl group and a group having a hydrocarbon group adjacent to the carbonyl group include acryloyloxymethyl succinic acid, methacryloyloxymethyl succinic acid, acryloyloxyethyl succinic acid, methacryloyloxyethyl succinic acid, and acryloyl. (Meth) acryloyloxyalkyl succinic acid having 1 to 4 carbon atoms in the alkyl group such as oxypropyl succinic acid, methacryloyloxypropyl succinic acid, acryloyloxybutyl succinic acid, methacryloyloxybutyl succinic acid; acetoacetoxymethyl acrylic acid, aceto Acetoxymethyl methacrylic acid, acetoacetoxyethyl acrylic acid, acetoacetoxyethyl methacrylic acid, acetoacetoxypropyl acrylic acid, acetoacetoxypropyl methacrylic acid Acetoacetoxyalkyl (meth) acrylic acid having 1 to 4 carbon atoms in the alkyl group such as acetoacetoxybutylacrylic acid and acetoacetoxybutylmethacrylic acid; diacetone acrylamide, diacetone methacrylamide; N- (2-oxomethyl) acrylamide, N- (2-oxomethyl) methacrylamide, N- (2-oxoethyl) acrylamide, N- (2-oxoethyl) methacrylamide, N- (2-oxopropyl) acrylamide, N- (2-oxopropyl) methacrylamide, N- (2-oxoalkyl) (meth) acrylamide having 1 to 4 carbon atoms in the alkyl group such as N- (2-oxobutyl) acrylamide and N- (2-oxobutyl) methacrylamide; N- (methaneamidomethyl) Acrylamide, N- (Me Tanamidomethyl) methacrylamide, N- (methaneamidoethyl) acrylamide, N- (methaneamidoethyl) methacrylamide, N- (methaneamidopropyl) acrylamide, N- (methaneamidopropyl) methacrylamide, N- (methanamide) Butyl) acrylamide, N- (methaneamidobutyl) methacrylamide, N- (ethaneamidomethyl) acrylamide, N- (ethaneamidomethyl) methacrylamide, N- (ethaneamidoethyl) acrylamide, N- (ethaneamidoethyl) methacryl Amides, N- (ethaneamidopropyl) acrylamide, N- (ethaneamidopropyl) methacrylamide, N- (ethaneamidobutyl) acrylamide, N- (ethaneamidobutyl) methacrylamide, N- (propanamide) Chill) acrylamide, N- (propanamidomethyl) methacrylamide, N- (propanamidoethyl) acrylamide, N- (propanamidoethyl) methacrylamide, N- (propanamidopropyl) acrylamide, N- (propanamidopropyl) methacryl Amide, N- (propanamidobutyl) acrylamide, N- (propanamidobutyl) methacrylamide, N- (butanamidomethyl) acrylamide, N- (butanamidomethyl) methacrylamide, N- (butanamidoethyl) acrylamide, N -(Butanamidoethyl) methacrylamide, N- (butanamidopropyl) acrylamide, N- (butanamidopropyl) methacrylamide, N- (butanamidobutyl) acrylamide, N- (butanamide) Til) methacrylamide, N- (pentanamidomethyl) acrylamide, N- (pentanamidomethyl) methacrylamide, N- (pentanamidoethyl) acrylamide, N- (pentanamidoethyl) methacrylamide, N- (pentanamidopropyl) Alkanes such as acrylamide, N- (pentanamidopropyl) methacrylamide, N- (pentanamidobutyl) acrylamide, N- (pentanamidobutyl) methacrylamide have 1 to 6 carbon atoms, and the alkyl group has 1 carbon atom. Although N- (alkanamidoalkyl) (meth) acrylamide etc. of -4 are mentioned, this invention is not limited only to this illustration.

  The content rate of the group having a carbonyl group and a hydrocarbon group adjacent to the carbonyl group in the (meth) acrylic polymer has a carbonyl group in the monomer component and a group having a hydrocarbon group adjacent to the carbonyl group. It can be easily adjusted by adjusting the monomer content.

  The content of the monomer having a carbonyl group and a group having a hydrocarbon group adjacent to the carbonyl group in the monomer component is preferably 1% by mass or more, more preferably 3% from the viewpoint of improving adhesiveness. % Or more, more preferably 5% by mass or more, from the viewpoint of improving the weather resistance and electrical output characteristics and improving the appearance of the backsheet, preferably 98% by mass or less, more preferably 95% by mass or less, Preferably it is 90 mass% or less.

  In the monomer component, another monomer is used as a monomer other than the monomer having a carbonyl group and a group having a hydrocarbon group adjacent to the carbonyl group. The other monomer is adjusted so that the total amount of the monomer having a carbonyl group and a group having a hydrocarbon group adjacent to the carbonyl group is 100% by mass. Therefore, the content of other monomers in the monomer component is preferably 2% by mass or more, more preferably 5% by mass from the viewpoint of improving weather resistance and electrical output characteristics and improving the appearance of the backsheet. % Or more, more preferably 10% by mass or more, and from the viewpoint of improving adhesiveness, it is preferably 99% by mass or less, more preferably 97% by mass or less, and still more preferably 95% by mass or less.

  Other monomers can be appropriately selected and used according to the properties required for the resulting (meth) acrylic polymer.

  Other monomers include, for example, a monomer having a carboxyl group, an acidic phosphate monomer, a monomer having a hydroxyl group, a (meth) acrylic acid ester, a monomer having a nitrogen atom, 2 Monomers having more than one polymerizable double bond, aromatic monomers, monomers having halogen atoms, vinyl ester monomers, vinyl ether monomers, etc. However, 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-acryloyloxymethyl acid phosphate, 2-methacryloyloxymethyl acid phosphate, 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, and the like. 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 hydroxyl group include carbons of alkyl groups such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and hydroxybutyl methacrylate. 1 to 4 (meth) acrylic acid hydroxyalkyl; caprolactone-modified 2-hydroxyethyl acrylate, caprolactone-modified 2-hydroxyethyl methacrylate and other alkyl groups having 1 to 4 carbon atoms such as caprolactone-modified hydroxyalkyl (meth) acrylate Hydroxyl group-containing (meth) acrylic acid ester having 1 to 4 carbon atoms of alkyl group; methyl α-hydroxymethyl acrylate, methyl α-hydroxymethyl methacrylate, ethyl α-hydroxymethyl acrylate , Α-hydroxyalkyl acrylates having 1 to 4 carbon atoms in each alkyl group such as ethyl α-hydroxymethyl methacrylate and the like are exemplified, but the present invention is not limited to such examples. These monomers having a hydroxyl group may be used alone or in combination of two or more. 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.

  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, and n-acrylate. Alkyl (meth) acrylates having 1 to 8 carbon atoms in alkyl groups such as -butyl, n-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate Cycloalkyl (meth) acrylate having 3 to 8 carbon atoms of cycloalkyl group such as isobornyl acrylate, isobornyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate; cyclohexylmethyl acrylate, methacrylic acid Alkyl groups such as cyclohexylmethyl, cyclohexylethyl acrylate, cyclohexylethyl methacrylate, cyclohexylpropyl acrylate, cyclohexylpropyl methacrylate, 4-methylcyclohexylmethyl acrylate and 4-methylcyclohexylmethyl methacrylate have 1 to 8 carbon atoms. And cycloalkylalkyl (meth) acrylate having 3 to 8 carbon atoms in the cycloalkyl group, 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 a nitrogen atom include (meth) acrylamide such as acrylamide and methacrylamide, N, N′-dimethylaminoethyl acrylate, N, N′-dimethylaminoethyl methacrylate, and N, N acrylic acid. -Nitrogen atom-containing (meth) acrylic acid esters such as diethylaminoethyl, N, N-diethylaminoethyl methacrylate, acrylic imide, methacrylic imide, etc. are included, but the present invention is not limited to such examples only. Absent. 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 the vinyl ether monomer include butyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, and the like, 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 other monomers, a monomer having a hydroxyl group and a (meth) acrylic acid ester are preferable, a hydroxyalkyl (meth) acrylate having 1 to 4 carbon atoms in the alkyl group, and a carbon number in the alkyl group. Alkyl (meth) acrylate having 1 to 8 and cycloalkyl (meth) acrylate having 3 to 8 carbon atoms in the cycloalkyl group are more preferable. These monomers may be used alone or in combination of two or more.

  In addition, from the viewpoint of improving weather resistance and blocking resistance, the other monomer may be a monomer having an ultraviolet absorbing group such as a benzotriazole monomer, a benzophenone monomer, or a triazine monomer. A monomer; a monomer having an ultraviolet-stable group may be included. 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, etc. Can do. Monomers having a UV-stable group can be easily obtained commercially, for example, as Adeka Stub series such as Adeka Stub LA-82, ADK STAB LA-87, and the like, manufactured by ADEKA Corporation.

The monomer component may contain acrylic acid having a basic structure of bisarylfluorene from the viewpoint of improving hydrolysis resistance and insulation resistance. Acrylic acid having bisarylfluorene as a basic structure is commercially easily available as, for example, Osaka Gas Chemical Co., Ltd., trade names: Ogsol EA-0200, Ogsol EA-0200, Ogsol EA-0500, Ogsol EA-1000, etc. Can be obtained. Examples of the monomer component include cyclohexyl alkyl ester of (meth) acrylic acid, dicyclopentenyl (meth) acrylic acid, dicyclopentenyloxyethyl (meth) as disclosed in JP-A-2002-69130. Acrylic acid, dicyclopentanyl (meth) acrylic acid, tricyclo [5.2.1.0 ^2.6 ] dec-8-yl (meth) acrylic acid, terpene (meth) acrylic acid, and the like can also be contained.

  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 bulk polymerization method, a dispersion polymerization method, a suspension polymerization method, and an emulsion polymerization method, but the present invention is limited only to such examples. It is not a thing.

  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 selected from the range of 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. Moreover, it is preferable that the atmosphere in superposition | polymerization is inert gas, such as nitrogen gas and argon gas, for example.

  By polymerizing the monomer component as described above, a (meth) acrylic polymer is obtained. The weight average molecular weight of the (meth) acrylic polymer obtained is preferably 5,000 to 1,000,000, more preferably 10,000 to 500,000, and still more preferably 30,000 to 300,000. The weight average molecular weight is a value when measured by gel permeation chromatography (GPC) with a polystyrene standard.

  The hydroxyl value of the (meth) acrylic polymer (nonvolatile content) is preferably from 0.1 to 200 mgKOH / g, more preferably from 1 to 100 mgKOH / g, from the viewpoint of improving adhesiveness and blocking resistance. Preferably it is 3-60 mgKOH / g.

  The (meth) acrylic adhesive of the present invention contains the (meth) acrylic polymer. The content of the (meth) acrylic polymer (nonvolatile content) in the (meth) acrylic adhesive is preferably 5 to 80% by mass, more preferably 5 to 60% by mass, from the viewpoint of improving adhesiveness and weather resistance. %. The content rate of the (meth) acrylic polymer (nonvolatile content) in the (meth) acrylic adhesive can be adjusted by adjusting the amount of the organic solvent contained in the (meth) acrylic adhesive. Examples of the organic solvent include organic solvents used in preparing the (meth) acrylic polymer, but the present invention is not limited by the type of the organic solvent.

  The non-volatile content of the (meth) acrylic adhesive may be composed of only the (meth) acrylic polymer, but other polymers are included as long as the purpose of the present invention is not impaired. It may be.

  The (meth) acrylic adhesive of the present invention may contain a curing agent from the viewpoint of improving hydrolysis resistance and insulation resistance.

  Examples of the curing agent include (block) polyisocyanate compounds, epoxy resins, oxazoline group-containing resins, aminoplast resins, and the like, but the present invention is not limited to such examples. These curing agents may be used alone or in combination of two or more. Among the curing agents, at least one monomer selected from the group consisting of a (block) polyisocyanate compound, an epoxy resin, and an oxazoline group-containing resin is preferable from the viewpoint of curability and weather resistance. ) 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.

  The block polyisocyanate compound crosslinks the adhesive by heating, but has properties and adhesiveness that improve storage stability at room 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. It is further excellent in adhesion to the filler used in the battery. 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 E-405-80T, Duranate TPA-B80E, Duranate MF-B60X, Duranate MF-K60X, etc. Can do.

  The amount of the (block) polyisocyanate compound is not particularly limited. For example, the amount of isocyanate group in the (block) polyisocyanate compound per mole of hydroxyl group in the (meth) acrylic polymer is preferably 0 from the viewpoint of improving the hydrolysis resistance and insulation resistance of the adhesive layer. .6 mol or more, more preferably 0.8 mol or more, preferably from the viewpoint of preventing the unreacted isocyanate group from reacting with moisture in the air to foam or whiten the adhesive layer. 1.4 mol or less, more preferably 1.2 mol or less.

  Examples of the epoxy resin include Japan Epoxy Resin Co., Ltd., trade names: Epicoat 828, Epicoat 1001X70, Epicoat 815; Asahi Denka Kogyo Co., Ltd., trade name: Adeka Resin EP-4100. Is not limited to such examples.

  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 (meth) acrylic polymer and aminoplast resin [(meth) acrylic polymer / aminoplast resin] is preferably 6/4 or more from the viewpoint of improving adhesiveness, From the viewpoint of improving the hydrolysis resistance and adhesion of the adhesive layer, it 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. Usually, 100 parts by mass of a (meth) acrylic polymer having an ethylenically unsaturated double bond at the end of the side chain From the viewpoint of hydrolysis resistance and insulation resistance of the adhesive layer, preferably 1 part by mass or more, more preferably 3 parts by mass or more, and from the viewpoint of improving adhesiveness, preferably 60 parts by mass or less, More preferably, it is 50 mass parts or less, More preferably, it is 30 mass parts or less.

  The (meth) acrylic adhesive of the present invention can be cured under various curing conditions depending on its use and the type of curing agent used in the (meth) acrylic adhesive. The (meth) acrylic adhesive of the present invention can be used as a room temperature curable type, a heat curable type, an ultraviolet curable type, or an electron beam curable type. Moreover, there is no limitation in particular in the quantity of a hardening | curing agent, its addition method, a dispersion method, etc. For example, when a (meth) acrylic polymer having an ethylenically unsaturated double bond at the end of the side chain has a plurality of hydroxyl groups in one molecule, it cures according to the (meth) acrylic polymer. What is necessary is just to adjust the quantity of an agent and to select the addition method and the dispersion method.

  In the (meth) acrylic adhesive of the present invention, if necessary, in order to promote the crosslinking reaction between the (meth) acrylic polymer having an ethylenically unsaturated double bond at the end of the side chain and the curing agent. The curing catalyst may be contained. 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.

  Further, the (meth) acrylic adhesive of the present invention may contain additives. Examples of the additive include additives generally used in resin compositions that form films and coating films. 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; anti-sagging agents; silane coupling agents; titanium white, complex oxide pigments Pigment dispersants; Phosphorus antioxidants, antioxidants such as phenolic antioxidants; viscosity modifiers; UV stabilizers; metal deactivators; Flame retardants; Reinforcers; Plasticizers; Lubricants; Rust preventives; Fluorescent brighteners; Organic and inorganic UV absorbers, inorganic heat absorbers; Organic and inorganic barriers Examples include flame retardants; 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 adhesiveness, for example, polyester resins, modified polyolefin resins, ethylene-vinyl acetate copolymers (hereinafter referred to as EVA), polyvinyl butyral ( PVB), silicone resins, vinyl chloride resins, polyurethanes, thermoplastic resins such as amino group-containing resins, and tackifiers may be included.

  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, coumarone tackifiers, Coumarone indene tackifier, styrene resin tackifier, xylene resin tackifier, phenol resin tackifier, petroleum resin tackifier, etc. Each agent 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 Yasuhara 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 tackifier may be appropriately adjusted according to the desired tackiness, and is not particularly limited, but from the viewpoint of improving the tackiness to the adherend per 100 parts by weight of the (meth) acrylic polymer, The amount is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and preferably 200 parts by mass or less, more preferably 150 parts by mass or less, from the viewpoint of suppressing a decrease in adhesive strength.

  The adherend to which the (meth) acrylic adhesive of the present invention can be applied is, for example, an adherend comprising a polymer obtained by polymerizing a monomer component containing a carboxylic acid vinyl ester. An adherend made of polyester, an adherend made of polycarbonate, an adherend made of a fluororesin, an adherend made of a (meth) acrylic resin, and the like. It is not something. Among these adherends, polyester base materials and fluororesin base materials are preferable from the viewpoint of weather resistance and cost.

  The (meth) acrylic adhesive of the present invention has an advantage that it can be suitably used for an adherend composed of a polymer obtained by polymerizing a monomer component containing a carboxylic acid vinyl ester. . Examples of the vinyl carboxylate include vinyl acetate, vinyl monochloroacetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, and vinyl stearate. Saturated aliphatic carboxylic acid vinyl esters which may have a substituent such as halogen atoms such as vinyl pivalate and vinyl octylate; alicyclic carboxylic acid vinyl esters such as cyclohexyl vinyl carboxylate; divinyl adipate; Examples thereof include unsaturated aliphatic carboxylic acid vinyl esters such as (meth) vinyl acrylate, vinyl crotonate, and vinyl sorbate; and aromatic carboxylic acid vinyl esters such as vinyl benzoate and vinyl cinnamate. Limited to illustration only Not intended to be.

  When the (meth) acrylic adhesive of the present invention is used for an adherend comprising a polymer obtained by polymerizing a monomer component containing a carboxylic acid vinyl ester, ) There is an advantage that the acrylic adhesive and the adherend can be firmly bonded.

  Further, in the present invention, in addition to the above-mentioned adherend, in view of heat resistance, strength physical properties, electrical insulation, hydrolysis resistance, etc., polyolefin resin, polyamide resin, polyarylate resin, etc. An adherend made of a resin can be used.

  Examples of the form of the adherend include a molded body formed into a predetermined shape including a film, a plate, and the like, but the present invention is not limited to such an example. A suitable adherend in the present invention includes a film made of a resin containing an ethylene-vinyl acetate copolymer.

  Applications of adherends include, for example, solar cell encapsulants, agricultural resin films, construction civil engineering resin sheets, automotive exterior parts, food packaging paper, laminated materials with a paper-coated resin surface, artificial grass The present invention is not limited only to such illustrations.

  Moreover, the back sheet | seat for solar cell modules in which the adhesive bond layer which consists of the said (meth) acrylic-type adhesive agent was formed by apply | coating the (meth) acrylic-type adhesive agent of this invention to the backsheet used for a solar cell module. Can be manufactured. In the back sheet for a solar cell module on which the adhesive layer is formed, the surface on which the adhesive layer is formed is a surface to be bonded to the filler constituting the solar cell module. As a back sheet, what is normally used for a solar cell should just be used, and this invention is not limited by the kind of the said back sheet.

  Examples of the filler include EVA, polyvinyl butyral, silicone resin, vinyl chloride resin, polyurethane, and the like, but the present invention is not limited to such examples. Among these, EVA is preferable from the viewpoints of weather resistance and flame retardancy and enhancing the adhesive strength. The thickness after drying of the adhesive layer made of the (meth) acrylic adhesive of the present invention formed on the surface to be bonded to the filler constituting the solar cell module is preferably from the viewpoint of adhesion and weather resistance. Is 0.1 μm or more, more preferably 0.3 μm or more, and further preferably 1 μm or more. From the viewpoint of preventing embrittlement, it is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 10 μm or less.

  FIG. 1 is a schematic cross-sectional view showing the configuration of a back sheet for a solar cell module in which the substrate is bonded with an adhesive. FIG. 1 has the simplest structure of a solar cell module backsheet. 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 (meth) acrylic adhesives of the present invention, (meth) acrylic adhesives other than the (meth) acrylic adhesives of the present invention, polyester adhesives, polyurethane adhesives, and polycarbonates. Although a system adhesive etc. are mentioned, this invention is not limited only to this illustration. The adhesive 2 is preferably the (meth) acrylic adhesive of the present invention from the viewpoints of adhesiveness and weather resistance. An adhesive layer 4 made of the (meth) acrylic adhesive of the present invention is formed on one surface of the two substrates 1 and 1.

  The (meth) acrylic adhesive 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 considered when evaluating a solar cell module. However, it has excellent adhesion and weather resistance to the filler used in the solar cell, maintains an electrical output characteristic, and exhibits an excellent effect that it is difficult to cause poor appearance of the backsheet.

  FIG. 2 is a schematic cross-sectional view showing another embodiment when the barrier layer 3 is interposed in the solar cell module backsheet. In FIG. 2, adhesives 2 and 2 are applied to one surface of each of the two substrates 1 and 1, and an adhesive layer formed by the adhesives 2 and 2 on the two substrates 1 and 1 The two substrates are integrated with a barrier layer 3 such as a gas barrier layer interposed therebetween, and the (meth) acrylic adhesive of the present invention is attached to the surface to be bonded to the filler constituting the solar cell module. An adhesive layer 4 is formed. Also in the solar cell module backsheet of this embodiment, since the adhesive layer 4 made of the (meth) acrylic adhesive of the present invention is formed, not only the environment actually used as a solar cell, but also the solar Even when an accelerated test is performed in a high-temperature and high-humidity atmosphere that is considered when evaluating the battery module, it has excellent adhesion and weather resistance to fillers used in solar cells, and maintains electrical output characteristics. An excellent effect is exhibited that it is difficult to cause poor appearance of the backsheet.

  Among the back sheet shown in FIG. 1 and the back sheet shown in FIG. 2, the adhesive shown in FIG. 1 is preferable from the viewpoint of cost reduction.

  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, metal vapor deposition films, such as an aluminum vapor deposition film which vapor-deposited metals, such as aluminum, to a polyester film and a polyolefin-type stretched film, for example are mentioned.

  Examples of the oxide vapor-deposited film include a film obtained by vapor-depositing aluminum oxide, silicon dioxide, tin oxide, magnesium oxide, indium oxide, and complex oxides thereof on a polyester film, and is transparent and has a gas barrier such as oxygen and water vapor. The thing which has property etc. are mentioned. 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 an oxide deposition layer include a vacuum deposition method, a thin film formation method such as a sputtering method, an ion plating method, and a plasma vapor deposition method (CVD). However, the present invention is not limited to such examples.

  Before applying the (meth) acrylic adhesive of the present invention to the adherend, from the viewpoint of improving the adhesive strength between the (meth) acrylic adhesive of the present invention and the adherend, the surface of the adherend It is preferable to apply an organic peroxide to the substrate, to include the organic peroxide in the (meth) acrylic adhesive of the present invention, or to previously include the organic peroxide in the adherend. . In particular, when an adherend composed of a polymer obtained by polymerizing a monomer component containing a carboxylic acid vinyl ester is used as the adherend, an organic peroxide is formed on the surface of the adherend. To improve the adhesive strength between the (meth) acrylic adhesive of the present invention and the adherend by applying the organic peroxide to the (meth) acrylic adhesive of the present invention. Can do.

  Examples of the organic peroxide include diacyl peroxides such as dibenzoyl peroxide, diisobutyl peroxide, ditrimethoxyhexanoyl peroxide, dilauroyl peroxide, disuccinic acid peroxide, di (methylbenzoyl) peroxide, and diisononyl peroxide. Oxides; ketone peroxides such as methyl ethyl ketone peroxide, cyclohexane peroxide, acetylacetone peroxide; tert-butylperoxyneodecanoate, tert-butylperoxybenzoate, tert-butylperoxyneoheptanoate, tert-butylperoxide Oxypivalate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxyisobutyrate, te t-butylperoxyacetate, tert-butylperoxyisononanoate, tert-hexylperoxypivalate, tert-hexylperoxy-2-ethylhexanoate, tert-hexylperoxyisopropylmonocarbonate, tetramethylbutyl Alkyl peroxyesters such as peroxyethylhexanoate and 2,5-dimethyl-2,5-di (ethylhexanoylperoxy) hexanoate; di-n-propylperoxycarbonate, tert-butylperoxy-2-ethylhexyl Carbonate, diisopropylperoxycarbonate, di (4-tert-butylcyclohexyl) peroxycarbonate, di (2-ethylhexyl) peroxydicarbonate, disec-butylperoxydi -Bonate, tert-butylperoxy-2-ethylhexyl carbonate, tert-butylperoxyisopropyl carbonate, 1,6-bis (tert-butylperoxycarboxy) hexane, bis (4-tert-butylcyclohexyl) peroxydicarbonate, Peroxycarbonates such as tert-amylperoxy-2-ethylhexyl carbonate, di (sec-butyl) peroxydicarbonate; dicumyl peroxide, tert-butylperoxy-2-ethylhexyl carbonate, di (isopropyl) peroxycarbonate , Di (4-tert-butylcyclohexyl) peroxycarbonate, di (2-ethylhexyl) peroxydicarbonate, di (sec-butyl) peroxydicar Tert-butylperoxy-2-ethylhexyl carbonate, tert-butylperoxyisopropyl carbonate, 1,6-bis (tert-butylperoxycarboxy) hexane, bis (4-tert-butylcyclohexyl) peroxydicarbonate, Although dialkyl peroxides, such as tert-amyl peroxy-2-ethylhexyl carbonate, are mentioned, this invention is not limited only to this illustration. These organic peroxides may be used alone or in combination of two or more.

When applying the organic peroxide to the surface of the adherend, if necessary, the organic peroxide may be dissolved in an organic solvent to a desired concentration, and the resulting solution may be applied to the adherend. . The coating amount (solid content) of the organic peroxide on the adherend cannot be unconditionally determined because it varies depending on the type of the organic peroxide, but is usually about 0.01 to 1 g / m ^2. It is preferable that When the organic peroxide is contained in the (meth) acrylic adhesive of the present invention, the content of the organic peroxide in the (meth) acrylic adhesive of the present invention is the type of the organic peroxide, etc. However, it is usually preferable to be about 0.01 to 10% by mass.

  Further, from the viewpoint of stabilizing and improving the gas barrier property of the (meth) acrylic adhesive 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 adherend. An overcoat layer made of a portion of polyvinyl alcohol or a completely saponified product and a silane compound may be provided on the oxide vapor deposition layer.

  The (meth) acrylic adhesive of the present invention is applied on the adherend by a method such as gravure coating, roll coating, bar coating, reverse coating, etc. so that the film thickness after drying becomes 0.1 to 20 μm. After bonding other substrates on the substrate by a method such as dry lamination, an adhesive layer made of a (meth) acrylic adhesive on the surface to be bonded to the filler constituting the solar cell module By forming the solar cell module, the solar cell module can be manufactured. 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 (meth) acrylic adhesive of the present invention is not only promoted in an 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 the solar cell module. Even when the test is performed, the adhesive and weather resistance to the filler used in the solar cell are excellent, the electric output characteristics are maintained, and the excellent effect of hardly causing the appearance failure of the back sheet is exhibited.

  The solar cell module in which the (meth) acrylic adhesive of the present invention is used can be easily obtained, for example, by replacing the (meth) acrylic adhesive of the present invention as a back sheet in a commonly used solar cell module. Can be configured. 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.

  Therefore, the (meth) acrylic adhesive of the present invention can be suitably used as a solar cell module adhesive for bonding a back sheet used for a solar cell module and a filler. The back sheet in which the adhesive layer made of the (meth) acrylic adhesive of the present invention is formed on the surface to be bonded to the filler constituting the solar cell module is preferably used as the back sheet for the solar cell module. Can do. The solar cell module having this solar cell module backsheet can be suitably used for solar cells.

  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.
<Base material 1>
Teijin DuPont Films Co., Ltd., trade name: Tetron U298W [white polyethylene terephthalate (hereinafter referred to as PET) film]
<Substrate 2>
Product name: Tech Barrier (silicon dioxide vapor-deposited PET film), manufactured by Mitsubishi Plastics, Inc.
<Base material 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.

Production Example 1
In a 500 ml flask equipped with a stirrer, dripping port, thermometer, condenser and nitrogen gas inlet, 60 g of ethyl acetate was charged, nitrogen gas was introduced, and the ethyl acetate was refluxed at about 80 ° C. with stirring. It was. In this flask, 84 g of cyclohexyl methacrylate, 2 g of 2-ethylhexyl acrylate, 9 g of 2-hydroxyethyl methacrylate and 5 g of 2-methacryloyloxyethyl succinic acid, 2,2′-azobis (2,4 -A mixture of 0.5 g of dimethylvaleronitrile) and 40 g of ethyl acetate was continuously dropped into the flask over 2 hours, and then heated for another 3 hours to contain the nonvolatile content of the (meth) acrylic polymer. A solution having a rate of 49.8% by mass was obtained. The obtained (meth) acrylic polymer (hereinafter referred to as polymer 1) had a hydroxyl value of 42 mgKOH / g and a weight average molecular weight of 110,000.

Production Example 2
In Production Example 1, the polymerization reaction was carried out in the same manner as in Production Example 1 except that the composition of the monomer component was changed to 84 g of cyclohexyl methacrylate, 2 g of 2-ethylhexyl acrylate, 9 g of 2-hydroxyethyl methacrylate, and 5 g of acetoacetoxyethyl methacrylate. As a result, a solution having a non-volatile content of 50.0% by mass of the (meth) acrylic polymer was obtained. The obtained (meth) acrylic polymer (hereinafter referred to as polymer 2) had a hydroxyl value of 42 mgKOH / g and a weight average molecular weight of 120,000.

Production Example 3
In Production Example 1, the polymerization reaction was carried out in the same manner as in Production Example 1 except that the composition of the monomer component was changed to 84 g of cyclohexyl methacrylate, 2 g of 2-ethylhexyl acrylate, 9 g of 2-hydroxyethyl methacrylate, and 5 g of diacetone acrylamide. As a result, a solution having a non-volatile content of 49.7% by mass of the (meth) acrylic polymer was obtained. The obtained (meth) acrylic polymer (hereinafter referred to as polymer 3) had a hydroxyl value of 42 mgKOH / g and a weight average molecular weight of 130,000.

Production Example 4
In Production Example 1, the polymerization reaction was performed in the same manner as in Production Example 1 except that the composition of the monomer component was changed to 45 g of cyclohexyl methacrylate, 2 g of 2-ethylhexyl acrylate, 9 g of 2-hydroxyethyl methacrylate, and 44 g of diacetone acrylamide. As a result, a solution having a non-volatile content of 49.8% by mass of the (meth) acrylic polymer was obtained. The obtained (meth) acrylic polymer (hereinafter referred to as polymer 4) had a hydroxyl value of 42 mgKOH / g and a weight average molecular weight of 110,000.

Production Example 5
In Production Example 1, the polymerization reaction was carried out in the same manner as in Production Example 1 except that the composition of the monomer component was changed to 9 g of cyclohexyl methacrylate, 2 g of 2-ethylhexyl acrylate, 9 g of 2-hydroxyethyl methacrylate and 80 g of diacetone acrylamide. As a result, a solution having a non-volatile content of 49.7% by mass of the (meth) acrylic polymer was obtained. The obtained (meth) acrylic polymer (hereinafter referred to as polymer 5) had a hydroxyl value of 42 mgKOH / g and a weight average molecular weight of 120,000.

Production Example 6
In Production Example 1, the polymerization reaction was carried out in the same manner as in Production Example 1 except that the composition of the monomer component was changed to 89 g of cyclohexyl methacrylate, 2 g of 2-ethylhexyl acrylate, and 9 g of 2-hydroxyethyl methacrylate. A solution having a non-volatile content of 49.9% by mass of the (meth) acrylic polymer was obtained. The obtained (meth) acrylic polymer (hereinafter referred to as polymer 6) had a hydroxyl value of 42 mgKOH / g and a weight average molecular weight of 120,000.

Example 1
Polymer 1 and poly (polystyrene) in a proportion of 7 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) per 100 parts by mass of the nonvolatile content of polymer 1 obtained in Production Example 1. The adhesive 1 was obtained by putting an isocyanate hardening | curing agent in a container, and diluting with ethyl acetate so that a non volatile matter density | concentration might be 10 mass%.

Example 2
Polymer 2 and poly (polystyrene) in a proportion of 7 parts by mass of polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) per 100 parts by mass of the non-volatile content of polymer 2 obtained in Production Example 2. An isocyanate curing agent was put in a container, and diluted with ethyl acetate so that the nonvolatile content concentration was 10% by mass, whereby an adhesive 2 was obtained.

Example 3
Polymer 3 and poly (polystyrene) in a proportion of 7 parts by mass of polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) per 100 parts by mass of the non-volatile content of polymer 3 obtained in Production Example 3. An isocyanate curing agent was placed in a container, and diluted with ethyl acetate so that the nonvolatile content concentration was 10% by mass, whereby an adhesive 3 was obtained.

Example 4
Polymer 4 and poly 4 in a proportion of 7 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) per 100 parts by mass of the nonvolatile content of polymer 4 obtained in Production Example 4. The adhesive agent 4 was obtained by putting an isocyanate hardening agent in a container and diluting with ethyl acetate so that a non volatile matter concentration might be 10 mass%.

Example 5
Polymer 5 and poly 5 in a proportion of 7 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) per 100 parts by mass of the nonvolatile content of polymer 5 obtained in Production Example 5. The adhesive 5 was obtained by putting an isocyanate hardening agent in a container and diluting with ethyl acetate so that a non volatile matter concentration might be 10 mass%.

Comparative Example 1
Polymer 6 and polyisocyanate at a ratio of 7 parts by mass of a polyisocyanate curing agent (manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur N3200) per 100 parts by mass of the nonvolatile content of polymer 6 obtained in Production Example 6. The adhesive 6 was obtained by putting an isocyanate hardening agent in a container and diluting with ethyl acetate so that a non volatile matter concentration might be 10 mass%.

Experimental example (Preparation of back sheet for solar cell module)
As shown in Table 1, any one of the adhesives 1 to 6 was used, and the adhesive was applied to the substrate 1 so that the coating amount after drying was 1 g / m ² and dried at 100 ° C. for 1 minute. By doing so, an adhesive layer was formed. Thereafter, in order from the filler side to the base materials 1 to 3, the surface of the base material 1 on which the adhesive layer is not formed is overlapped with the adhesive X, so that the base material 1 / adhesive X / base material 2 By laminating in the order of / adhesive X / base material 3 and laminating by a dry laminating method, a laminate was obtained. The obtained laminated body was cured at 50 ° C. for 5 days to produce a back sheet for a solar cell module.

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 resistance]
The back sheet for a solar cell module obtained above 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 [manufactured by Toray Industries, Inc. , Product name: Lumirror X10S] (hereinafter referred to as untreated PET film), a weight of 5 kg is placed on the resulting laminate, and the laminate is placed in an oven at a temperature of 40 ° C. For 24 hours. Then, the laminated body was taken out from the oven, the adhesive layer of the laminated body was visually observed, and blocking resistance was evaluated based on the following evaluation criteria.

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

〔Adhesiveness〕
One sheet obtained by cutting the back sheet obtained above to a width of 60 mm and a length of 200 mm, and an EVA sheet (manufactured by Mitsui Chemicals Fabro Co., Ltd., product number: RC02B, thickness: 400 μm) to a width of 60 mm and a length of 90 mm One sheet cut and tempered glass (width: 10 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. 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. Obtained.

  In an atmosphere where the temperature is 23 ° C. and the relative humidity is 65%, the tempered glass plate and EVA sheet of the unbonded portion of the sample obtained above are respectively attached to the upper and lower clips of the autograph (manufactured by Shimadzu Corporation). The peeling strength (initial value) at a crosshead speed of 300 mm / min with a width of 25 mm was measured by sandwiching and 180-degree peeling method, and the adhesiveness was 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 85% relative humidity for 1000 hours or 2000 hours, the peel strength was measured under the same conditions as described above. The adhesiveness was evaluated based on the evaluation 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 the solar cells made of polycrystalline silicon sandwiched between the layers, the back sheet obtained above was further provided thereon so that the adhesive layer was in contact with the EVA sheet, thereby obtaining a laminate. .

Next, 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 carry out a crosslinking reaction. Proceeded. Then, the sample was produced by performing a frame with an aluminum frame.

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, all of the (meth) acrylic adhesives obtained in each example are excellent in blocking resistance, and the (meth) acrylic adhesive obtained in Comparative Example 1 was used. In contrast to the environment actually used as a solar cell, it is used for a solar cell even when an accelerated test is performed in a high-temperature and high-humidity atmosphere that is considered when evaluating a solar cell module. It can be seen that it is excellent in adhesiveness and weather resistance to the resulting filler, maintains electric output characteristics, and is excellent in the appearance of the back sheet. Therefore, it turns out that all can use the (meth) acrylic-type adhesive agent obtained in each Example suitably for a solar cell module and a solar cell.

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

Claims (5)

  A (meth) acrylic adhesive containing a (meth) acrylic polymer, wherein the (meth) acrylic polymer has a carbonyl group and a group having a hydrocarbon group adjacent to the carbonyl group (meta ) A (meth) acrylic adhesive characterized by being an acrylic polymer.   The (meth) acrylic adhesive according to claim 1, wherein the (meth) acrylic polymer has a carbonyl group and a group having a hydrocarbon group adjacent to the carbonyl group in the side chain.   A back sheet for a solar cell module, wherein an adhesive layer made of the (meth) acrylic adhesive according to claim 1 or 2 is formed.   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.