JP5197340B2 - Solar battery backsheet - Google Patents

Description

The present invention relates to a solar battery back sheet . More particularly, to a solar cell back sheet comprising a laminate formed by coating a black color coating composition to the resin film.

In general, when the resin base material is irradiated with ultraviolet rays contained in sunlight or the like, the main chain of the resin is broken, so that the mechanical strength of the resin base material is lowered. Therefore, in order to protect the resin substrate from ultraviolet rays, an ultraviolet-absorbing composite film in which an acrylic polymer layer is formed on the treated surface of the resin substrate that has been subjected to an easy adhesion treatment has been proposed (for example, , See Patent Document 1). However, this ultraviolet-absorbing composite film is excellent in ultraviolet-absorbing property, adhesion to a resin base material, and weather resistance, but requires a complicated easy adhesion treatment.
JP 11-348199 A

The present invention has been made in view of the prior art, and is excellent in weather resistance, moist heat resistance and light shielding properties, without being subjected to complicated easy adhesion treatment, and in coating strength and adhesion to a substrate. and to provide even better solar battery backsheet black coating composition comprising a laminate used to form a coating film.

The present invention provides a solar cell back sheet comprising a laminate having a coating film formed on the resin film and the resin film, the coating film is UV stable monomer, carbonization of 4 to 25 carbon atoms having a hydrogen group (meth) acrylate monomer and the black color you containing and a black pigment acrylic polymer and a curing agent having a hydroxyl group-containing by polymerizing a monomer mixture containing a monomer hydroxyl The present invention relates to a solar battery back sheet, which is formed by coating a coating composition on a resin film and curing .

Solar battery backsheet of the present invention, even without performing a complicated adhesion facilitating treatment, weather resistance, excellent wet heat resistance and light shielding properties, have a coating strength and coating film excellent in adhesion to the resin film that Sosu an excellent effect that.

As described above, the solar cell backsheet of the present invention is a solar cell backsheet comprising a laminate having a resin film and a coating film formed on the resin film, wherein the coating film is a UV-stable single layer. mer, hydrocarbon containing the group (meth) acrylate monomer of 4 to 25 carbon atoms [hereinafter simply "(meth) acrylate monomer" hereinafter] and a monomer containing a hydroxyl group-containing monomer the mixture of the acrylic polymer and the black color coating composition you contain a curing agent and a black pigment having a hydroxyl group by polymerizing coated on a resin film, and features that you have been formed by curing To do.

  As used herein, “(meth) acryl” means “acryl” and / or “methacryl”.

Since the black paint composition used for the solar battery backsheet of the present invention uses a specific acrylic polymer and black pigment, it can be applied to a resin base material without performing a complicated easy adhesion treatment. By doing so, a coating film that shields light can be easily formed, so that deterioration of the resin base material due to light can be prevented. Moreover, the black coating composition used for the solar cell backsheet of the present invention is excellent in weather resistance, moist heat resistance and light shielding properties, and can form a coating film excellent in coating film strength and adhesion to a substrate. it can.

  Examples of the ultraviolet stable monomer include compounds having a polymerizable double bond and an ultraviolet stable group in the molecule. Suitable UV stable monomers include, for example, formula (I):

Wherein R ¹ is a hydrogen atom or a cyano group, R ² and R ³ are each independently a hydrogen atom or a methyl group, R ⁴ is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, Z is an oxygen atom or an imino group Group)
The monomer represented by these is mentioned.

In the monomer represented by the formula (I), examples of the alkyl group having 1 to 18 carbon atoms represented by R ⁴ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, Examples include tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, and the like. .

  Specific examples of the monomer represented by the formula (I) include 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyloxy-2,2 , 6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine 4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2 , 2,6,6-tetramethylpiperidine and the like, but the present invention is not limited to such examples. These monomers may be used alone or in combination of two or more.

  In the monomer mixture used in the present invention, a (meth) acrylate monomer is used together with an ultraviolet stable monomer. The carbon number of the hydrocarbon group contained in the (meth) acrylate monomer is 4 to 25, preferably 4 to 18 from the viewpoint of enhancing weather resistance, coating strength, and adhesion to the substrate.

  Examples of (meth) acrylate monomers include isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isoamyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. , Isononyl (meth) acrylate, isodecyl (meth) acrylate, tert-butylhexyl (meth) acrylate and other alkyl groups having 4 to 25 carbon atoms; cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl C4-C25 alicyclic hydrocarbon groups such as (meth) acrylate and cyclododecyl (meth) acrylate; bornyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate Polycyclic hydrocarbon groups having 4 to 25 carbon atoms such as dicyclopentanyl (meth) acrylate; lauryl (meth) acrylate, stearyl (meth) acrylate, terpene (meth) acrylate, etc. The invention is not limited to such examples. These monomers may be used alone or in combination of two or more.

  Among the (meth) acrylate monomers, the formula (II):

Wherein R ⁵ is a hydrogen atom or a methyl group, Y is an alkyl group having a branched chain having 4 to 25 carbon atoms, an alicyclic hydrocarbon group having 4 to 25 carbon atoms, or a polycyclic group having 4 to 25 carbon atoms. (Indicates hydrocarbon group)
The (meth) acrylate monomer represented by is preferable from the viewpoint of improving weather resistance, coating film strength, and adhesion to a substrate.

  In the formula (II), Y represents an alkyl group having a branched chain having 4 to 25 carbon atoms, an alicyclic hydrocarbon group having 4 to 25 carbon atoms, or a polycyclic hydrocarbon group having 4 to 25 carbon atoms. Examples of the alkyl group having a branched chain having 4 to 25 carbon atoms include branched chains such as isobutyl group, sec-butyl group, tert-butyl group, isoamyl group, 2-ethylhexyl group, isononyl group, and isodecyl group. The alkyl group which has is mentioned. Examples of the alicyclic hydrocarbon group having 4 to 25 carbon atoms include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, and a cyclododecyl group. Examples of the polycyclic hydrocarbon group having 4 to 25 carbon atoms include a bornyl group and an isobornyl group.

  The number of carbon atoms in Y is preferably large from the viewpoint of increasing hydrophobicity. Y is preferably an alkyl group having a branched chain having 4 to 25 carbon atoms and an alicyclic hydrocarbon group having 4 to 25 carbon atoms from the viewpoint of increasing hydrophobicity, and the branched chain having 4 to 18 carbon atoms is preferably represented by Y. It is more preferable that they are an alkyl group having and an alicyclic hydrocarbon group having 4 to 18 carbon atoms.

  Among the (meth) acrylate monomers, cyclohexyl (meth) acrylate and tert-butyl (meth) acrylate are preferable from the viewpoint of improving weather resistance, coating strength, and adhesion to the substrate.

  The mass ratio of the UV-stable monomer and the (meth) acrylate monomer [UV-stable monomer / (meth) acrylate-based monomer] increases the strength of the coating film and has excellent weather resistance. From the viewpoint of forming a coating film excellent in adhesiveness to the material, it is preferably 0.01 / 1 or more, more preferably 0.02 / 1 or more, which increases the water resistance of the formed coating film and reduces yellowing. From the viewpoint of preventing, it is preferably 2/1 or less, more preferably 1.5 / 1 or less.

Monomer mixture is containing an ultraviolet stability monomer and (meth) acrylate monomer, further containing a hydroxyl group-containing monomer.

Since the hydroxyl group-containing monomer used in the present invention, it is possible to further improve the dispersibility of the adhesion and pigment to the substrate. Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth) acrylate and its ε-caprolactone adduct, but the present invention is not limited to such examples. Hydroxyalkyl (meth) acrylate and its ε-caprolactone adduct may be used alone or in combination of two or more.

  Specific examples of hydroxyalkyl (meth) acrylate and its ε-caprolactone adduct include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl. (Meth) acrylate, 4-hydroxybutyl (meth) acrylate and other alkyl group having 1 to 4 carbon atoms of hydroxyalkyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate ε-caprolactone 1 mol adduct, 2 -Ε- of hydroxyalkyl (meth) acrylate having 1 to 4 carbon atoms, such as ε-caprolactone 2 mol adduct of hydroxyethyl (meth) acrylate, ε-caprolactone 3 mol adduct of 2-hydroxyethyl (meth) acrylate, etc. Capro Although a Kuton adduct etc. are mentioned, this invention is not limited only to this illustration. These monomers may be used alone or in combination.

  The content of the hydroxyl group-containing monomer in the monomer mixture is preferably 1% by mass or more, more preferably 3% by mass or more, from the viewpoint of improving adhesion to the substrate and improving weather resistance. From the viewpoint of improving the water resistance and weather resistance of the coating film, it is preferably 25% by mass or less, more preferably 20% by mass or less.

  Moreover, the monomer mixture may contain the ultraviolet absorptive monomer from a viewpoint of providing an ultraviolet absorptivity. Suitable ultraviolet absorbing monomers include, for example, ultraviolet absorbing monomers described in JP-A-2008-56859, but the present invention is not limited to such examples. Among the ultraviolet absorbing monomers, monomers represented by the formulas (2) to (5) described in the above publication are preferable.

  Specific examples of the ultraviolet absorbing monomer include 2- [2′-hydroxy-5 ′-(methacryloyloxymethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxy). Ethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-tert-butyl-5 ′-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 '-Tert-butyl-3'-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -5-chloro-2H-benzotriazole, 2- [2′-Hydroxy-5 ′-(methacryloyloxyethyl) phenyl] -5-meth Monomer represented by the formula (2) described in the publication, such as shea -2H- benzotriazole;

2-hydroxy-4- [2- (meth) acryloyloxy] ethoxybenzophenone, 2-hydroxy-4- [2- (meth) acryloyloxy] butoxybenzophenone, 2,2′-dihydroxy-4- [2- (meta ) Acryloyloxy] ethoxybenzophenone, 2-hydroxy-4- [2- (meth) acryloyloxy] ethoxy-4 '-(2-hydroxyethoxy) benzophenone, 2-hydroxy-3-tert-butyl-4- [2- (Meth) acryloyloxy] ethoxybenzophenone, 2-hydroxy-3-tert-butyl-4- [2- (meth) acryloyloxy] butoxybenzophenone, and the like represented by the formula (3) described in the above publication ;

2- [2-hydroxy-4- (2-methacryloyloxyethoxy) phenyl] -4,6-diphenyl-1,3,5-triazine, 2,4-diphenyl-6- [2-hydroxy-4- (2 -Acryloyloxy) phenyl] -1,3,5-triazine, 2,4-bis (2-methylphenyl) -6- [2-hydroxy-4- (2-acryloyloxyethoxy) phenyl] -1,3 5-triazine, 2,4-bis (2-methoxyphenyl) -6- [2-hydroxy-4- (2-acryloyloxyethoxy) phenyl] -1,3,5-triazine, 2,4-bis (2 -Ethylphenyl) -6- [2-hydroxy-4- (2-acryloyloxyethoxy) phenyl] -1,3,5-triazine, 2,4-bis (2-ethoxyphenyl) -6 2-hydroxy-4- (2-acryloyloxyethoxy) phenyl] -1,3,5-triazine, 2,4-diphenyl-6- [2-hydroxy-4- (2-methacryloyloxyethoxy) phenyl] -1 , 3,5-triazine, 2,4-bis (2-methylphenyl) -6- [2-hydroxy-4- (2-methacryloyloxyethoxy) phenyl] -1,3,5-triazine, 2,4- Bis (2-methoxyphenyl) -6- [2-hydroxy-4- (2-methacryloyloxyethoxy) phenyl] -1,3,5-triazine, 2,4-bis (2-ethylphenyl) -6- [ 2-hydroxy-4- (2-methacryloyloxyethoxy) phenyl] -1,3,5-triazine, 2,4-bis (2-ethoxyphenyl) -6- [2-hydride Xy-4- (2-methacryloyloxyethoxy) phenyl] -1,3,5-triazine, 2,4-bis (2,4-dimethoxyphenyl) -6- [2-hydroxy-4- (2-acryloyloxy) Ethoxy) phenyl] -1,3,5-triazine, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4- (2-acryloyloxyethoxy) phenyl] -1,3 5-triazine, 2,4-bis (2,4-diethoxyphenyl) -6- [2-hydroxy-4- (2-acryloyloxyethoxy) phenyl] -1,3,5-triazine, 2,4- Bis (2,4-diethylphenyl) -6- [2-hydroxy-4- (2-acryloyloxyethoxy) phenyl] -1,3,5-triazine, 2- [2-hydroxy-4- ( 11-acryloyloxy-undecyloxy) phenyl] -4,6-diphenyl-1,3,5-triazine, 2- [2-hydroxy-4- (11-methacryloyloxy-undecyloxy) phenyl] -4, 6-diphenyl-1,3,5-triazine, 2- [2-hydroxy-4- (11-acryloyloxy-undecyloxy) phenyl] -4,6-bis (2,4-dimethylphenyl) -1, 3,5-triazine, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4- (11-Metaku Li acryloyloxy undecyloxy) phenyl] -1,3,5-triazine , 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4- (2-Metaku Li acryloyloxy ethoxy) phenyl] -1,3,5-triazine Monomer represented by the formula (4) described in the above publication and the like;

2- [2′-hydroxy-3 ′-(meth) acryloylamino-5 ′-(1,1,3,3-tetramethylbutyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3 '-(Meth) acryloylaminomethyl-5'-(1,1,3,3-tetramethylbutyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-3 '-(meth) acryloylaminophenyl ] -2H-benzotriazole, 2- [2′-hydroxy-3 ′-(meth) acryloylaminomethylphenyl] -2H-benzotriazole, etc., the monomer represented by the formula (5) described in the above publication, etc. However, the present invention is not limited to such examples. These monomers may be used alone or in combination of two or more.

  The content of the UV-absorbing monomer in the monomer mixture is preferably 2% by mass or more, more preferably 5% by mass or more, and further preferably 10% by mass or more from the viewpoint of sufficiently imparting UV-absorbing property. From the viewpoint of enhancing the adhesion to the substrate, it is preferably 70% by mass or less, more preferably 50% by mass or less, and further preferably 5% by mass or less.

  In the present invention, the monomer mixture may contain other monomers in an appropriate amount within a range not impairing the object of the present invention. Examples of other monomers include (meth) acrylates other than the (meth) acrylate monomers, vinyl ester monomers, silicon atom-containing monomers, halogen atom-containing monomers, and nitrogen atom-containing monomers. Monomers, polyfunctional monomers, vinyl ether monomers, epoxy group-containing monomers, acidic group-containing monomers, and the like can be mentioned, but the present invention is not limited to such examples.

  Examples of (meth) acrylates other than the (meth) acrylate monomers include, for example, 1 to 3 carbon atoms of an alkyl group such as methyl (meth) acrylate, ethyl (meth) acrylate, and n-propyl (meth) acrylate. The alkyl (meth) acrylate, 2-acetoacetoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, and the like are included, 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 vinyl ester monomers include vinyl acetate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, and vinyl cyclohexanecarboxylate. , Vinyl pivalate, vinyl octylate, vinyl monochloroacetate, divinyl adipate, vinyl methacrylate, vinyl crotonate, vinyl sorbate, vinyl benzoate, vinyl cinnamate, etc. It is not limited. These monomers may be used alone or in combination of two or more.

  Examples of the silicon atom-containing monomer include vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltrimethoxysilane, vinyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, and trimethylsiloxyethyl. Although (meth) acrylate etc. are mentioned, this invention is not limited only to this illustration. These monomers may be used alone or in combination of two or more.

  Examples of the halogen atom-containing monomer include trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, and octafluoropentyl (meth). Acrylate, heptadodecafluorodecyl (meth) acrylate, β- (perfluorooctyl) ethyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, ethylene oxide addition (meth) acrylate of tribromophenol, Although tribromophenyl (meth) acrylate etc. are mentioned, this invention is not limited only to this illustration. These monomers may be used alone or in combination of two or more.

  Examples of the nitrogen atom-containing monomer include N-2-hydroxy-3-acryloyloxypropyl-N, N, N-trimethylammonium chloride, N-methacryloylaminoethyl-N, N, N-dimethylbenzylammonium chloride. , Quaternary ammonium base-containing monomers such as N-methacryloyloxy-N, N, N-triethylammonium ethyl sulfate; N, N-dimethylaminopropylacrylamide, N, N-dimethylaminoethylacrylamide, N, N- Dimethylaminopropyl acrylate, N, N-dimethylaminoethyl acrylate, acryloylmorpholine, N-2-hydroxy-3-acryloyloxypropyl-N, N-dimethylamine, N-3-methacryloyloxy-2-hydroxypropyl-N, -Tertiary amino group-containing monomers such as diethylamine, (meth) acrylamide, methylenebis (meth) acrylamide, N-methylol (meth) acrylamide, (meth) acryloyloxyethyltrimethylammonium chloride, dimethylaminoethyl (meth) ) Acrylate sulfate, morpholine ethylene oxide addition (meth) acrylate, N-vinylpyridine, N-vinylimidazole, N-vinylpyrrole, N-vinylpyrrolidone, N-vinyloxazolidone, N-vinylsuccinimide, N-vinylmethyl Carbamate, N, N-methylvinylacetamide, 2-isopropenyl-2-oxazoline and the like 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 polyfunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, Polyethylene glycol-propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerin di (meth) acrylate 2-hydroxy-1,3-di (meth) acryloxypropane di (meth) acrylate, 2,2-bis [4- (meth) acryloxydiethoxyphenyl] propanedi (meth) acrylate 2,2-bis [4- (methacryloxypolyethoxy) phenyl] propane di (meth) acrylate, ethylene oxide modified bisphenol A di (meth) acrylate, propylene oxide modified bisphenol A di (meth) acrylate, trimethylolpropane tri (meth) ) Acrylate and the like, 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 vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isopropyl ether, vinyl n-propyl ether, vinyl isobutyl ether, vinyl n-butyl ether, vinyl n-amyl ether, vinyl isoamyl ether. , Vinyl-2-ethylhexyl ether, vinyl-n-octadecyl ether, cyanomethyl vinyl ether, 2,2-dimethylaminoethyl vinyl ether, 2-chloroethyl vinyl ether, β-difluoromethyl vinyl ether, benzyl vinyl ether, phenyl vinyl ether, divinyl ether, divinyl Although acetal etc. are mentioned, this invention is not limited only to this illustration. These monomers may be used alone or in combination of two or more.

  Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, α-methylglycidyl acrylate, α-methylglycidyl methacrylate, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, and the like. 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 acidic group-containing monomer include sulfoethyl (meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxypropyl acid phosphate, and the like. It is not limited to illustration only. These monomers may be used alone or in combination of two or more.

  The acrylic polymer can be easily prepared by polymerizing the monomer mixture.

  Examples of the method for polymerizing the monomer mixture include a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and an emulsion polymerization method, but the present invention is not limited to such a polymerization method. Among these polymerization methods, the solution polymerization method is preferable because the obtained reaction mixture can be used as it is.

  Hereinafter, one embodiment of preparing an acrylic polymer by subjecting a monomer mixture to a solution polymerization method will be described, but the present invention is not limited to only that embodiment.

  Examples of the solvent used for solution polymerization of the monomer mixture include aromatic solvents such as toluene and xylene; alcohol solvents such as n-butyl alcohol, propylene glycol methyl ether, diacetone alcohol, and ethyl cellosolve; Examples include ester solvents such as ethyl acetate, butyl acetate, and cellosolve acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and dimethylformamide. However, the present invention is not limited to such examples. The amount of the solvent is preferably appropriately determined according to the concentration of the monomer mixture, the molecular weight of the target acrylic polymer, and the like.

  Examples of the polymerization initiator include 2,2′-azobis- (2-methylbutyronitrile), tert-butylperoxy-2-ethylhexanoate, 2,2′-azobisisobutyronitrile, benzoyl Although a peroxide, di-tert-butyl peroxide, etc. are mentioned, this invention is not limited only to this illustration. The amount of the polymerization initiator is usually preferably 0.01 to 30 parts by mass, more preferably 0.05 to 10 parts by mass per 100 parts by mass of the monomer mixture.

  In the polymerization, for example, a chain transfer agent such as n-dodecyl mercaptan may be used in order to adjust the molecular weight of the resulting acrylic polymer.

  The polymerization temperature for polymerizing the monomer mixture is usually preferably 40 to 200 ° C, more preferably 40 to 140 ° C.

  Since the polymerization time of the monomer mixture varies depending on the polymerization temperature, the composition of the monomer mixture, the type and amount of the polymerization initiator, etc., it cannot be determined unconditionally, and may be appropriately determined according to them. preferable.

  The weight average molecular weight of the acrylic polymer is preferably 50000 or more, more preferably 60000 or more from the viewpoint of improving the adhesion to the substrate, and from the viewpoint of enhancing the appearance and storage stability of the formed coating film. Preferably it is 500,000 or less, More preferably, it is 400,000 or less.

In the present invention, since the polymerization of a monomer mixture containing a water-acid group-containing monomer, the acrylic polymer is have a hydroxyl group. Since the acrylic polymer and a curing agent having a hydroxyl group are used in combination, the reaction of the acrylic polymer and a curing agent having a hydroxyl group, Ru can be further improved curability of the black color coating composition .

  Examples of the curing agent include polyfunctional isocyanate compounds and melamine resins. Among these, a polyfunctional isocyanate compound is preferable from the viewpoint of weather resistance.

  As polyfunctional isocyanate compounds, aromatic polyisocyanates having two or more isocyanate groups, aliphatic polyisocyanates having two or more isocyanate groups, alicyclic polyisocyanates having two or more isocyanate groups, mixtures thereof, Examples thereof include modified polyisocyanates obtained by modification. Among these, aliphatic polyisocyanates and alicyclic polyisocyanates are preferable from the viewpoint of improving weather resistance.

  Specific examples of the polyfunctional isocyanate compound include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, naphthylene diisocyanate, xylylene diisocyanate, polymethylene polyphenylene diisocyanate and other aromatic polyisocyanates, hexamethylene diisocyanate, lysine diisocyanate and other fats. Aliphatic polyisocyanates, hydrogenated methylene diphenyl diisocyanates, hydrogenated tolylene diisocyanates, isophorone diisocyanates and other alicyclic polyisocyanates, mixtures thereof, and modified products thereof. Examples of the modified product include a prepolymer modified product, a nurate modified product, a urea modified product, a carbodiimide modified product, an allophanate modified product, and a burette modified product, which are reaction products with polyol.

When a polyfunctional isocyanate compound is used as the curing agent, the ratio of the acrylic polymer to the polyfunctional isocyanate compound is as follows: NCO group of polyfunctional isocyanate compound / OH group (hydroxyl group) of acrylic polymer (NCO group / OH group: equivalent ratio) is to increase the storage stability of the black color coating composition, from the viewpoint of improving the mechanical strength of the coating film, preferably 0.8 / 1 to 1.2 / 1, more preferably 0.9 /1-1.15/1, more preferably 0.95 / 1-1.1 / 1.

In the black paint composition, a black pigment is used as a colorant. Examples of the black pigment include carbon black, black iron oxide (triiron tetroxide), black titanium oxide, copper manganese black, copper chrome black, cobalt black, cyanine black, and aniline black. It is not limited only to such illustration. These black pigments may be used alone or in combination of two or more. Among these, carbon black is preferable from the viewpoint of light shielding properties. Examples of carbon black include furnace black, acetylene black, and thermal black, but the present invention is not limited to such examples. The black pigment may be used in combination with a colorant such as another pigment or dye as long as the object of the present invention is not impaired.

  The particle diameter of the black pigment is usually 1 μm or less, more preferably 0.5 μm or less from the viewpoint of forming a smooth coating film, although it depends on the thickness of the coating film. In addition, the particle diameter of the black pigment is preferably 0.01 μm or more, more preferably 0.1 μm or more, from the viewpoint of improving dispersibility.

  The amount of the black pigment is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, from the viewpoint of preventing deterioration of the resin base material due to light per 100 parts by mass of the resin solid content of the acrylic polymer. More preferably, it is 0.5 parts by mass or more, and from the viewpoint of preventing embrittlement of the formed coating film, it is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, further preferably 6 parts by mass or less. is there.

Note that the black coating composition, to the extent that the purpose is not hindered in the present invention, as the resin other than the acrylic polymer, for example, may be included, such as saturated polyester resin. Moreover, the black coating composition, if necessary, may contain additives and organic solvents.

  Examples of additives include organic ultraviolet absorbers such as benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, triazine ultraviolet absorbers, and indole ultraviolet absorbers, and inorganic ultraviolet absorbers such as zinc oxide. UV absorbers; addition-type UV stabilizers such as sterically hindered piperidine compounds; leveling agents; antioxidants; talc and other fillers; rust inhibitors; antifungal agents; dispersion stabilizers; plasticizers; Surfactants, lithium-based and organoboron-based antistatic agents; flame retardants such as phosphorus compounds, nitrogen compounds, boron compounds, halogen compounds; thickeners; antifoaming agents; inorganic fine particles such as colloidal silica and alumina sol; Examples include acrylic resin fine particles, but the present invention is not limited to such examples. Since the amount of the additive varies depending on the type of the additive and cannot be determined unconditionally, it is preferable to appropriately adjust the amount within the range in which the object of the present invention is not impaired.

Examples of the organic solvent include aromatic solvents such as toluene and xylene; alcohol solvents such as n-butyl alcohol, propylene glycol methyl ether, diacetone alcohol, and ethyl cellosolve; esters such as butyl acetate, ethyl acetate, and cellosolve acetate Examples of the solvent include ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; dimethylformamide and the like, but the present invention is not limited to such examples. The solvent amount is preferably appropriately adjusted within a range of purposes of the present invention is not inhibited.

The black paint composition can be applied to various substrates. Examples of the material constituting the substrate include polyester, polyethylene, polypropylene, triacetyl cellulose, polystyrene, polycarbonate, polyethersulfone, cellophane, polyamide, polyvinyl alcohol, polyacetal, polyphenylene ether, polyphenylene sulfide, polyimide, polyamideimide, poly Fluorine resin such as etherimide, polyetheretherketone, polytetrafluoroethylene, ABS resin, noryl resin, acrylic resin, epoxy resin, and other inorganic materials such as glass, slate, mortar, iron, copper, aluminum, magnesium However, the present invention is not limited to such examples.

The black coating composition, among these substrates can be suitably used in the resin substrate. Especially, the adhesiveness with respect to the base material which was excellent with respect to the base material which consists of resin, such as polyester, is expressed. Examples of the polyester include polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. Each of the base materials made of these resins may be composed of a single layer or may have a laminated structure in which a plurality of layers are laminated.

A resin film etc. are mentioned as a representative example of a resin base material. As a suitable resin film, a polyester film etc. are mentioned, for example. Among the resin film, from the viewpoint of improving the adhesion between the black color coating composition, the number average molecular weight of the polyester film is more preferably from 18,000 to 40,000. The polyester film can be easily obtained commercially, for example, as a product name: Lumirror (registered trademark) X10 manufactured by Toray Industries, Inc.

  Since the thickness of the resin film varies depending on its use, etc., it cannot be determined unconditionally. Therefore, it is preferable to appropriately determine the thickness of the resin film according to its use. For example, when the resin film is used for a solar battery back sheet or the like, the thickness of the resin film is preferably 5 to 300 μm, more preferably 20 to 150 μm. In addition, in order to provide water vapor barrier properties, for example, a metal oxide vapor deposition layer may be formed on the surface of the resin film by vapor deposition of a metal oxide such as aluminum oxide.

As a method of applying a black colored coating composition to a substrate such as a resin film, for example, spray coating, brush coating, curtain flow coating, gravure coating, roll coating, spin coating, bar coating , including an electrostatic coating method, a method of immersing the substrate in the black coating composition and the like, and the present invention is not limited only to those exemplified.

After coating the black color coating composition to a substrate such as a resin film, performing heat to cure the black color coating composition. The heating temperature and heating time, the black heat-resistant temperature, such as by different because of the substrate composition and the resin film of the coating composition unconditionally can not be determined, usually, preferably 70 to 150 ° C., more preferably 80-130 ° C. The heating time is usually preferably 20 seconds to 3 minutes, more preferably 30 seconds to 2 minutes. After the black coating composition is cured, for example, it is preferable to cure the formed coating film at a temperature of about 30 to 60 ° C. for about 0.5 to 4 days.

Black color coating composition was coated on the surface of a substrate such as a resin film, the thickness of the coating film after drying, from the viewpoint of enhancing the light shielding property, preferably 1μm or more, more preferably 2μm or more Yes, from the viewpoint of enhancing the adhesion to a substrate such as a resin film, it is preferably 15 μm or less, more preferably 10 μm or less.

Black color coating composition by coating the resin film such as polyester film, it is possible to produce a product layer body as described above.

The laminate has a coating film formed by applying the black coating composition, and the coating film is excellent in weather resistance, moist heat resistance, and light shielding properties, and is resistant to coating film strength and resin film. Excellent adhesion. Therefore, the laminate can be suitably used as a solar cell back sheet.

In addition, the said laminated body can be laminated | stacked with another base material through an adhesive agent, and can be used as a 1 layer or more laminated body. Examples of other base materials include resin plates such as acrylic resin plates, colored films, resin films having gas barrier properties, water vapor-blocking resin films, and the like, but the present invention is limited only to such examples. is not.

  The adhesive does not have to be a special one, and may be any that can be easily obtained commercially. Examples of the adhesive include trade names manufactured by Shin-Etsu Polymer Co., Ltd .: Polymer Ace, hot melt adhesive manufactured by Toray Dow Corning Co., Ltd., etc., but the present invention is limited to such examples only. is not.

The black paint composition is excellent in adhesiveness with an adhesive such as a silicone-based adhesive, and has excellent properties such that the adhesiveness hardly decreases even after a wet heat test. Accordingly, the black coating composition may be used for electropositive Ikeba Kkushi preparative thick.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited to such examples.

Production Example 1
As a UV-stable monomer, 4-methacryloyloxy-1,2,2,6,6-penta was placed in a 500 mL flask equipped with a stirrer, a dripping port, a thermometer, a cooling tube and a nitrogen gas inlet. A monomer mixture consisting of 1 part of methylpiperidine, 79 parts of cyclohexyl methacrylate, 10 parts of 2-hydroxyethyl methacrylate and 10 parts of methyl methacrylate, and 120 parts of ethyl acetate as a solvent were added, refluxed while stirring with nitrogen gas flowing in The temperature was raised to.

  On the other hand, a mixture of 10 parts of ethyl acetate as a solvent and 0.2 part of 2,2′-azobis- (2-methylbutyronitrile) as a polymerization initiator was charged into a dropping tank and dropped into the flask over 2 hours. did. After completion of the dropwise addition, the reflux reaction was continued, cooled 6 hours after the start of the dropwise addition, diluted with ethyl acetate to give a solution having a nonvolatile content of 40% by mass, and an acrylic polymer having a weight average molecular weight of 167,000 (Table 1 The polymer number described in 1) was obtained.

  In each of the production examples, the weight average molecular weight of the acrylic polymer is determined by the gel permeation chromatography measuring apparatus [manufactured by Tosoh Corporation, product number: HLC8120] and the column [manufactured by Tosoh Corporation, product number: TSK-GEL. The molecular weight in terms of polystyrene was determined using GMHXL-L].

Production Examples 2-9
In Production Example 1, an acrylic polymer was prepared in the same manner as Production Example 1 except that the composition of the monomer mixture and the amount of the polymerization initiator were changed as shown in Table 1. In addition, each abbreviation shown in Table 1 means the following.
(UV stable monomer)
HALS1: 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine HALS2: 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine [(meth) acrylate-based single (Meter)
CHMA: cyclohexyl methacrylate t-BMA: tert-butyl methacrylate 2EHA: 2-ethylhexyl acrylate BA: butyl acrylate [hydroxyl group-containing monomer]
・ HEMA: 2-hydroxyethyl methacrylate [UV absorbing monomer]
UVA: 2- [2′-hydroxy-5 ′-(methacryloyloxymethyl) phenyl] -2H-benzotriazole [other monomer]
・ MMA: Methyl methacrylate

Example 1
To 100 parts (solid content) of the acrylic polymer obtained in Production Example 1, 2 parts of carbon black (manufactured by Mitsubishi Chemical Corporation, product number: MA100) as a black pigment (concentration of carbon black in nonvolatile content: 40% by mass) ) Was added and dispersed with a paint shaker for 1 hour to obtain a dispersion.

  Into the obtained dispersion, 5 parts of aliphatic polyisocyanate (burette-modified polyisocyanate) [manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur (registered trademark) N3200] [acrylic in dispersion] Hydroxyl group of aliphatic polymer / isocyanate group of aliphatic polyisocyanate (equivalent ratio): 1/1] was added. Then, it diluted with methyl ethyl ketone until the amount of non-volatiles became 20 mass%, and obtained the black coating composition.

  Next, a polyester film having a thickness of 125 μm as a base film (polyethylene terephthalate film, manufactured by Toray Industries, Inc., trade name: 5 μm after drying the resulting black coating composition with a bar coater) (Lumilar (registered trademark) X10S) and dried at 120 ° C. for 1 minute and then at 40 ° C. for 2 days to prepare a coating film having a coating film formed on the substrate film.

Examples 2-8 and Comparative Examples 21 to
A coating film was produced in the same manner as in Example 1 except that the composition of the black coating composition was changed as shown in Table 2 in Example 1.

In addition, all the quantity of each component of Table 2 is a solid content. Details of the black pigment and the curing agent are as follows.
Black pigment: carbon black [Mitsubishi Chemical Corporation, trade name: MA100]
Curing agent: aliphatic polyisocyanate (Buret-modified polyisocyanate) [manufactured by Sumika Bayer Urethane Co., Ltd., trade name: Desmodur (registered trademark) N3200]

  Next, a weather resistance test or a moist heat resistance test was performed on the coating film obtained in each example and comparative example by the following method.

[Weather resistance test]
Using an ultraviolet deterioration accelerating tester [Iwasaki Electric Co., Ltd., trade name: iSuper UV Tester UV-W131], in the atmosphere at 60 ° C. and 50% relative humidity, 100 mW / m from the coating film side of the coating film. Irradiation with cm ² ultraviolet rays was carried out for a predetermined time shown in Table 2.

[Moisture and heat resistance test]
Using a thermo-hygrostat [trade name: PL-2KH, manufactured by ESPEC CORP.], The coating film was allowed to stand in an atmosphere of 85% relative humidity at 85 ° C. for 250 hours or 500 hours as shown in Table 2.

  Next, the following physical properties were examined for the coating film after the weather resistance test or wet heat resistance test and the coating film when these tests were not performed. The results are shown in Table 2.

(A) Adhesiveness Adhesiveness was examined according to the description of JIS K 5600 5.6 (2004 edition). More specifically, using a cutter guide at 1 mm intervals in the atmosphere at 25 ° C., the substrate film (polyester film) is penetrated from the surface of the coating film formed on the coating film with a cutter knife. ) After attaching 100 1 mm square grid cuts, the cellophane adhesive tape [manufactured by Nichiban Co., Ltd., product number: CT405AP-18, width: 18 mm] is attached to the grid cut face, and eraser After rubbing from above to completely adhere the tape, fold the attached tape back and peel it off at a stretch in the horizontal direction with respect to the substrate, and determine the number of grids of the coating film remaining on the substrate film surface. Recorded. The adhesion was evaluated based on the following evaluation criteria. In addition, the greater the number of grids of the coating film remaining on the surface of the base film, the better the adhesion to the base film.

(Evaluation criteria)
4: The number of grids of the remaining coating film is 98 or more 3: The number of grids of the remaining coating film is 95 to 97 2: The number of grids of the remaining coating film is 85 -96 1: The number of grids of the remaining coating film is 84 or less

(B) Tensile strength It was obtained by cutting the coating film so as to have a width of 10 mm using a variable temperature tensile tester [manufactured by Shimadzu Corporation, trade name: Shimadzu Autograph AGS-100D]. The test piece was pulled in the atmosphere of 23 ° C. under the conditions of a distance between chucks of 40 mm and a tensile speed of 200 mm / min, and the tensile strength until breaking was measured. Tensile strength retention is given by the formula:
[Retention rate of tensile strength (%)] = [[Tensile strength after irradiation] − [Tensile strength before irradiation]] × 100
Based on. The tensile strength was evaluated based on the following evaluation criteria.

(Evaluation criteria)
3: Tensile strength retention is 90% or more 2: Tensile strength retention is 70% or more and less than 90% 1: Tensile strength retention is less than 70%

(C) Light-shielding property Using a UV-visible near-infrared spectrophotometer [manufactured by Shimadzu Corporation, product number: UV-3600], a coating film is irradiated with light having a wavelength of 400 to 800 nm, and a spectral transmission spectrum is measured. The light shielding properties were evaluated based on the following evaluation criteria. The lower the light transmittance, the better the shielding property.

(Evaluation criteria)
3: Light transmittance is 1% or less 2: Light transmittance exceeds 1% and 2% or less 1: Light transmittance exceeds 2%

(D) Adhesion A silicone adhesive (Shin-Etsu Chemical Polymer Co., Ltd., Polymer Ace) is applied to the coating film surface of the coating film to form an adhesive layer, and an acrylic resin plate [Nippon Test Panel ( Manufactured by Co., Ltd.] and then heated for 10 minutes in an atmosphere of 150 ° C. under a reduced pressure of 1.3 kPa, and the coating film is laminated and integrated with the acrylic resin plate via a silicone adhesive. Got.

  The obtained laminate was placed in a thermo-hygrostat [trade name: PL-2KH, manufactured by ESPEC CORP.] And the appearance after leaving the laminate for 500 hours in an atmosphere of 85% relative humidity at 85 ° C. was visually observed. And evaluated whether there was any abnormality such as floating or peeling between the coating film and the adhesive layer.

(Evaluation criteria)
2: No abnormality 1: Abnormalities such as floating and peeling are observed

From the results shown in Table 2, the following can be understood.
The black paint compositions obtained in each example are all in contrast to the black paint composition obtained in Comparative Example 2 in which no UV-stable monomer is used. It turns out that it is excellent in shielding property and adhesiveness.

From the results of Examples 1 to 8 , the UV-stable monomer / (meth) acrylate monomer (mass ratio) is 0.03 / 1 to 0.08 / 1, and the black pigment (carbon black) When the amount is 1.5 to 2.5 per 100 parts by mass (solid content) of the acrylic polymer (Examples 3 to 5), the adhesiveness, tensile strength, It can be seen that the light shielding properties and adhesiveness are comprehensively excellent. Further, since the used curing agent in Example 1-8, when the curing agent is not used in contrast to Comparative Example 1, it is found that the weather resistance is excellent even more.

From the above, the black coating composition is excellent in weather resistance, moist heat resistance and light shielding properties, and excellent in coating film strength and adhesion to a substrate without performing a complicated easy adhesion treatment. It turns out that there exists the outstanding effect of forming a coating film. Further, the laminate, the black coating composition Suruga have a coating film formed by coating a coating film, weather resistance, excellent in shielding property of moist heat resistance and light, coating strength It can also be seen that it has an excellent effect of being excellent in adhesion to the substrate.

The laminate used in the present invention has a coating film formed by applying the black coating composition, and the coating film has excellent weather resistance, moist heat resistance and light shielding properties, because it is excellent in adhesion to the resin film, it can be utilized as a solar Ikeba Kkushi bets.

Claims (6)

A laminate having a coating film formed on the resin film and the resin film A solar battery backsheet, the coating film has ultraviolet stability monomer, a hydrocarbon group having 4 to 25 carbon atoms (meth) acrylate monomer and a hydroxyl group-containing monomer containing the monomer mixture you containing an acrylic polymer and a curing agent and a black pigment having a hydroxyl group by polymerizing a black color coating composition A solar battery back sheet, which is formed by coating on a resin film and curing . A (meth) acrylate monomer having a hydrocarbon group having 4 to 25 carbon atoms is represented by the formula (II):
Wherein R ⁵ is a hydrogen atom or a methyl group, Y is an alkyl group having a branched chain having 4 to 25 carbon atoms, an alicyclic hydrocarbon group having 4 to 25 carbon atoms, or a polycyclic group having 4 to 25 carbon atoms. (Indicates hydrocarbon group)
The solar cell backsheet according to claim 1, which is a (meth) acrylate monomer represented by: Mass ratio of UV-stable monomer in acrylic polymer to (meth) acrylate monomer having 4 to 25 carbon atoms [UV-stable monomer / carbonization of 4 to 25 carbons] The solar cell backsheet according to claim 1 or 2, wherein the (meth) acrylate monomer having a hydrogen group] is 0.01 / 1 to 2/1. Hydroxyl group-containing monomer Gahi mud alkoxyalkyl (meth) acrylate or a solar cell back sheet according to claim 1 that is ε- caprolactone adduct. Solar battery back sheet according to any one of claims 1 to 4, which is a black pigment painter over carbon black. Solar battery back sheet according to claim 1 is a resin film Gapo Li ester film.