JP2001131473A - Coating agent composition for silicon wafer and solar cell module using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating agent composition for a silicone wafer permitting excellent productivity, good followup properties to a finely processed surface of a photoelectric conversion element composed of a silicone wafer and excellent conversion efficiency of light energy to electrical power owing to decrease in reflectance, and to provide a solar cell module using the same. SOLUTION: The coating agent composition for a silicon wafer comprises an ultraviolet-curable resin composition (I) comprising a urethane (meth)acrylate resin (A), a reactive diluent (B) and a photopolymerization initiator (C). Preferably, the urethane (meth)acrylate resin is obtained by reacting a polyol (a1), a polyisocyanate (a2) and a hydroxy(meth)acrylate (a3), and has a weight- average mol. wt., in terms of the standard polystyrene, of 1,000-30,000, a glass transition temperature of 250⊥C or below and 2-6 (meth)acryloyl groups in one molecule. The solar cell module has a multilayered structure comprising a substrate, the coating agent composition, a photoelectric conversion element and the coating composition in this order.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition for a silicon wafer and a solar cell module using the same, and more particularly, to a photovoltaic device comprising a silicon wafer, which has good followability and excellent workability. Furthermore, the present invention relates to a coating composition for silicon wafers having excellent power conversion efficiency of light energy and a solar cell module using the same.

[0002]

2. Description of the Related Art Solar cells are expected to be used as clean energy.
There is a well-known structure in which a solar cell element is vertically fixed with an adhesive sheet, and is protected and fixed with a transparent protective material on the upper part and a substrate protective material on the lower part. As such an adhesive sheet, an ethylene copolymer, in particular, an ethylene-vinyl acetate copolymer is already known.For example, a transparent film is provided on the front surface, a glass plate, an aluminum plate or a steel plate is provided on the back surface, and between them. An adhesive sheet such as an ethylene-vinyl acetate copolymer, a solar cell element (a photoelectric conversion element made of a silicon wafer), and the adhesive sheet are arranged.
At the same time as applying heat of 0 ° C. to melt the adhesive sheet, pressing and laminating under vacuum, and further performing a heat treatment at about 140 to 150 ° C. for crosslinking of the ethylene-vinyl acetate copolymer, It is manufactured by cutting excess transparent film and adhesive sheet and attaching output leads.

[0003] As described above, Japanese Patent Application Laid-Open Nos. 61-69179, 4-137770, 6-322334 disclose the use of an ethylene-vinyl acetate copolymer as such an adhesive sheet. JP-A-11-6
No. 1055 and the like.

[0004]

However, in the method using an adhesive sheet made of an ethylene-vinyl acetate copolymer, the adhesive sheet is melted by heating and simultaneously pressed and laminated under vacuum, so that workability is increased. And in recent years, Japanese Patent Application Laid-Open
No. 7, JP-A-8-97454 discloses a process for forming a V-shaped groove or recess on the light-receiving surface side of a light source conversion device substrate for the purpose of reducing light reflectance. The adhesive sheet made of the ethylene-vinyl acetate copolymer does not have the ability to follow such a processed surface, and the problem remains that the power conversion efficiency of light energy is reduced. there were.

[0005] Further, instead of coating the element with an adhesive sheet made of an ethylene-vinyl acetate copolymer, a method of coating the element with an ultraviolet curable resin is disclosed in Japanese Patent Laid-Open No. 55-38.
No. 071 and JP-A-59-4179, however, such an ultraviolet-curable resin has not been studied in detail, and further improvement is desired. JP-A-59-4179 relates to an amorphous solar cell.

Under such circumstances, in the present invention, the photoelectric conversion element made of a silicon wafer has good followability to a finely processed surface and excellent workability. An object of the present invention is to provide a coating composition for silicon wafers having excellent power generation conversion efficiency and a solar cell module using the same.

[0007]

Means for Solving the Problems However, the present inventors have conducted intensive studies in view of such circumstances, and as a result, have found that urethane (meth) acrylate resin (A) and reactive diluent (B)
The present inventors have found that a coating composition for silicon wafers comprising an ultraviolet-curable resin composition (I) containing a photopolymerization initiator (C) meets the above object, and completed the present invention. In the present invention, in particular, the photoelectric conversion element is coated with the coating composition for a silicon wafer and used as a solar cell module.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The urethane (meth) acrylate resin (A) used in the present invention is not particularly limited.
A urethane (meth) acrylate resin obtained by reacting 1), polyisocyanate (a2) and hydroxy (meth) acrylate (a3) is preferable.

The polyol (a1) is not particularly restricted but includes, for example, ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methylpentanediol, Pentyl glycol, cyclohexane dimethanol, hydrogenated bisphenol A, polycaprolactone, trimethylolethane, trimethylolpropane, polytrimethylolpropane, pentaerythritol, polypentaerythritol, sorbitol, mannitol, glycerin, polyglycerin, diethylene glycol, triethylene glycol, Tetraethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, Polyhydric alcohols and, polyhydric alcohol with maleic anhydride, such as tetramethylene glycol,
Polyester polyols, caprolactone-modified polyols, polyolefin-based polyols, polybutadiene-based polyols, ethylene oxide and / or propylene, which are condensates with polybasic acids such as maleic acid, fumaric acid, itaconic anhydride, itaconic acid, adipic acid, and isophthalic acid Oxide block copolymer polyols, ethylene oxide and / or propylene oxide random polyols, and the like can be mentioned.

Further, as the polyol (a1) component, a diol component and a triol component are added in 20 / 80-80.
/ 20 (weight ratio). More preferably, diol component / triol component = 40/60.
７５75/25 (weight ratio), particularly preferably diol component / triol component = 60 / 40-70 / 30 (weight ratio). If the ratio is less than 20/80, the curing shrinkage during curing by irradiation with ultraviolet rays becomes large, so that warpage or cracking of the cured product is liable to occur, and the adhesion to the member is significantly reduced. The curability due to ultraviolet irradiation is reduced, and a cured product having a surface tack of the cured product is obtained, which is not preferable.

Preferred combinations of the diol component and the triol component include a combination of ethylene oxide and / or propylene oxide random copolymerized polyether diol and ethylene oxide and / or random copolymerized polyether triol, and a combination of polytetramethylene glycol and polyester triol. Combinations and the like can be mentioned.

The polyisocyanate (a2) is not particularly restricted but includes, for example, aromatic, aliphatic, cycloaliphatic and alicyclic polyisocyanates. TDI), diphenylmethane diisocyanate (MDI), hydrogenated diphenylmethane diisocyanate (H-MDI), polyphenylmethane polyisocyanate (crude MDI),
Modified diphenylmethane diisocyanate (modified MD
I), hydrogenated xylylene diisocyanate (H-XD
I), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), trimethyl hexamethylene diisocyanate (TMXDI), tetramethyl xylylene diisocyanate (m-TMXD)
I), isophorone diisocyanate (IPDI), norbornane diisocyanate (NBDI), 1,3-bis (isocyanatomethyl) cyclohexane (H ₆ XDI)
Polyisocyanates such as these, trimer compounds of these polyisocyanates, and reaction products of these polyisocyanates and polyols are preferably used. Among them, trimethylhexamethylene diisocyanate (TMXDI),
Trimers of isophorone diisocyanate (IPDI) and hexamethylene diisocyanate are preferably used.

Further, the hydroxy (meth) acrylate (a3) is not particularly limited.
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxyethyl acryloyl phosphate, 4-butylhydroxy (meth) acrylate, 2- (meth) acryloy Roxyethyl-2-hydroxypropyl phthalate, glycerin di (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, modified with caprolactone Examples thereof include 2-hydroxyethyl (meth) acrylate, and among them, 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate are preferably used.

The method for producing the urethane (meth) acrylate resin (A) is not particularly limited as long as it is a method of reacting the polyol (a1), the polyisocyanate (a2), and the hydroxy (meth) acrylate (a3). A known method is adopted. For example, a method of mixing and reacting three components of polyol (a1), polyisocyanate (a2) and hydroxy (meth) acrylate (a3) at once, reacting polyol (a1) with polyisocyanate (a2), A method of forming a urethane isocyanate intermediate containing one or more isocyanate groups per molecule and then reacting the intermediate with a hydroxy (meth) acrylate (a3); a polyisocyanate (a2) and a hydroxy (meth) acrylate (a)
3) reacting to form a urethane (meth) acrylate intermediate containing one or more isocyanate groups per molecule, and then reacting the intermediate with the polyol (a1). A method is preferred in terms of stability and reduction of production time.

For example, after reacting the bifunctional polyol (a1) with the polyisocyanate (a2) at a reaction molar ratio of 1: 4.0 to 5.0, the reaction product may be further reacted with a trifunctional polyol if necessary. (A1) is reacted at a 0.5 molar ratio,
Further, the reaction product of the bifunctional polyol and the polyisocyanate and / or the reaction product of the trifunctional polyol and the polyisocyanate are reacted with hydroxy (meth) acrylate (a3) at a molar ratio of 5.5 to 6.0. Is preferred. In the above reaction, it is also preferable to use a catalyst such as dibutyltin dilaurate for the purpose of accelerating the reaction.

In the present invention, the polyol (a
It is also preferable to use a urethane (meth) acrylate resin obtained by reacting polyisocyanate (a2) with hydroxy (meth) acrylate (a3) without using 1). Polyisocyanate (a2) and hydroxy (meth)
The reaction of the acrylate (a3) is not particularly limited. For example, the polyisocyanate (a2) and the hydroxy (meth) acrylate (a3) may be used in a ratio of 1: 3.0 to 3.0.
The reaction is preferably performed at a reaction molar ratio of 3.5. Also in the above reaction, it is preferable to use a catalyst such as dibutyltin dilaurate for the purpose of accelerating the reaction.

Thus, the urethane (meth) acrylate resin (A) is obtained. In the present invention, the urethane (meth) acrylate resin is used.
The acrylate resin (A) has a weight average molecular weight of 1,000 to 30,00 in terms of standard polystyrene molecular weight.
0, more preferably from 8,000 to
28,000, particularly preferably 15,000 to 26.0
When the weight-average molecular weight is less than 1,000, the elongation of the cured product due to ultraviolet irradiation is low, the followability to deformation stress is deteriorated, and the material is easily broken.
Exceeding the range is not preferred because the surface hardness of the cured product due to the irradiation of ultraviolet rays becomes low, so that the cured product is easily scratched and the stain resistance is lowered.

The weight-average molecular weight in terms of standard polystyrene molecular weight is defined as high-performance liquid chromatography ("Showex GPC system-1" manufactured by Showa Denko KK).
Type 1 "), column: Shodex GPC KF-8
06 L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 10
0 to 2 × 10 ⁷ , theoretical plate number: 10,000 stages / unit, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm). .

Further, the urethane (meth) acrylate resin (A) preferably has a glass transition temperature of 250 ° C. or lower, more preferably 20 to 200 ° C., particularly preferably 60 to 180 ° C. If the glass transition temperature exceeds 250 ° C., the curing shrinkage during curing by irradiation with ultraviolet rays increases, and the adhesion to other members deteriorates, which is not preferable.

The urethane (meth) acrylate resin (A) preferably has 2 to 6 (meth) acryloyl groups per molecule. If the number of the (meth) acryloyl groups is less than 2, the curability by irradiation with ultraviolet rays will be poor, and the surface tack will be left on the cured product. If it exceeds 6, the curing shrinkage during curing by irradiation with ultraviolet rays will be large. This is not preferable because the adhesion to other members is deteriorated.

The reactive diluent (B) used in the present invention may be any one having at least one, preferably 1 to 5 ethylenically unsaturated groups in one molecule. Functional monomers include trifunctional and higher functional monomers.

Examples of the monofunctional monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-phenoxy-2-hydroxypropyl (meth) acrylate. , 2-hydroxy-3
-Phenoxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, glycerin mono (meth) acrylate, glycidyl (meth) acrylate, lauryl (meth) acrylate, n-butyl ( (Meth) acrylate, n-stearyl (meth) acrylate, benzyl (meth) acrylate, phenol ethylene oxide-modified (n = 2) (meth) acrylate, nonylphenol propylene oxide-modified (n = 2.
5) Half- (meth) acrylates of phthalic acid derivatives such as (meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, N-
Methylol (meth) acrylamide and the like.

Examples of the bifunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and propylene glycol di (meth) acrylate. , Dipropylene glycol di (meth)
Acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate,
Ethylene oxide modified bisphenol A type di (meth)
Acrylate, propylene oxide-modified bisphenol A type di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) Examples include acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, diglycidyl phthalate di (meth) acrylate, and hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate.

Examples of the trifunctional or higher functional monomer include, for example,
Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri (meth) acryloyloxyethoxy Trimethylolpropane, glycerin polyglycidyl ether poly (meth) acrylate and the like.

Among the above ethylenically unsaturated compounds (B), 2-hydroxy-3-phenoxypropyl (meth) acrylate, cyclohexyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate are particularly preferably used. The reactive diluent (B) may be used alone or in combination of two or more.

In the present invention, the urethane (meth) acrylate resin (A) and the ethylenically unsaturated compound (B)
Is the urethane (meth) acrylate resin (A) / ethylenically unsaturated compound (B) = 30/7.
It is preferably 0 to 90/10 (weight ratio), more preferably 40/60 to 80/20 (weight ratio),
Particularly preferably, it is 55/45 to 75/25 (weight ratio). At such a content ratio, the urethane (meth) acrylate resin (A) / ethylenically unsaturated compound (B)
When the ratio is less than 0/70, the elasticity of the cured product by ultraviolet irradiation is low and the elongation is low. When the urethane (meth) acrylate resin (A) / ethylenically unsaturated compound (B) is greater than 90/10, the mixture is reduced. Is unfavorable because the viscosity at room temperature increases, and the coating, coating and casting properties deteriorate.

The photopolymerization initiator (C) used in the present invention is not particularly limited, and known photopolymerization initiators can be used. For example, P, P'-bis (dimethylamino) benzophenone, P, P'-bis (diethylamino) benzophenone, P, P'-bis (dibutylamino) benzophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin phenyl ether, benzoin isobutyl ether, Benzoylbenzoic acid, methyl benzoylbenzoate,
Methyl benzoyl formate, benzyl diphenyl disulfide, benzyl dimethyl ketal, dibenzyl, diacetyl, anthraquinone, naphthoquinone, 3,3′-
Dimethyl-4-methoxybenzophenone, benzophenone, dichloroacetophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-diethylthioxanthone, 2,2-diethoxyacetophenone, 2,
2-dichloro-4-phenoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, phenylglyoxylate, α-hydroxyisobutylphenone, dibenzosparone, 1- (4-isopropylphenyl)-
2-hydroxy-2-methyl-1-propanone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone, tribromophenylsulfone,
Tribromomethylphenylsulfone, furthermore 2,4,6
-[Tris (trichloromethyl)]-1,3,5-triazine, 2,4- [bis (trichloromethyl)]-6
(4′-methoxyphenyl) -1,3,5-triazine, 2,4- [bis (trichloromethyl)]-6
(4′-methoxynaphthyl) -1,3,5-triazine, 2,4- [bis (trichloromethyl)]-6- (piperonyl) -1,3,5-triazine, 2,4- [bis (trichloro Methyl)]-6- (4′-methoxystyryl) -1,3,5-triazine and the like;
Acridine derivatives such as acridine and 9-phenylacridine, 2,2′-bis (o-chlorophenyl) -4,
5,4 ′, 5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (o-chlorophenyl) -4,
5,4 ', 5'-tetraphenyl-1,1'-biimidazole, 2,2'-bis (o-fluorophenyl)-
4,5,4 ', 5'-tetraphenyl-1,1'-biimidazole, 2,2'-bis (o-methoxyphenyl)
-4,5,4 ', 5'-tetraphenyl-1,1'-biimidazole, 2,2'-bis (p-methoxyphenyl) -4,5,4', 5'-tetraphenyl-1, 1 '
-Biimidazole, 2,4,2 ', 4'-bis [bi (p
-Methoxyphenyl)]-5,5'-diphenyl-1,
1'-biimidazole, 2,2'-bis (2,4-dimethoxyphenyl) -4,5,4 ', 5'-diphenyl-
1,1′-biimidazole, 2,2′-bis (p-methylthiophenyl) -4,5,4 ′, 5′-diphenyl-
1,1'-biimidazole, bis (2,4,5-triphenyl) -1,1'-biimidazole, etc.
No. 37377, 1,2'-, 1,4 '
Hexaarylbiimidazole derivatives such as tautomers covalently bonded at-, 2,4'-, triphenylphosphine, and 2-benzoyl-2-dimethylamino-1- [4-morpholinophenyl ] -Butane and the like.

The amount of the photopolymerization initiator (C) is 1 to 20 parts by weight based on 100 parts by weight of the total of the urethane (meth) acrylate resin (A) and the reactive diluent (B). Is preferred, more preferably 2 to 10 parts by weight,
Particularly preferably, it is 3 to 10 parts by weight. When the amount is less than 1 part by weight, curing by ultraviolet irradiation does not proceed in a short time and the film strength is low. When the amount is more than 20 parts by weight, the cured material does not exhibit the cured physical properties and is fragile to deformation and brittle. Not preferred.

Thus, the urethane (meth) acrylate resin (A), the reactive diluent (B) and the photopolymerization initiator (C)
To obtain an ultraviolet-curable resin composition (I) comprising
In the present invention, if necessary, the silane compound (D)
Is preferred in that the adhesion to the glass substrate is improved. It is also preferable to coat the silane-based compound (D) in advance on the glass substrate surface in close contact with the ultraviolet-curable resin composition (I).

The silane compound (D) is not particularly restricted but includes, for example, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane,
Silane compounds having a vinyl group such as vinyltris (β-methoxyethoxy) silane, β- (3,4 epoxycyclohexyl) -ethyltrimethoxysilane, β- (3
4 epoxycyclohexyl) -ethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ
Silane compounds having an epoxy group, such as glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyldisilane Ethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth)
(Meth) such as acryloxypropyltriethoxysilane
Silane compound having an acryloyl group, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-
β (aminoethyl) γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-
Silane compounds having an amino group such as phenyl-γ-aminopropyltrimethoxysilane, silane compounds having a chloro group such as γ-chloropropyltrimethoxysilane,
Examples include silane compounds having a mercapto group such as γ-mercaptopropyltrimethoxysilane.

Further, in the present invention, additives such as an antifoaming agent, a surfactant and a leveling agent can be blended.

Thus, the ultraviolet-curable resin composition (I) is obtained as described above, and the ultraviolet-curable resin composition (I) is obtained.
Is used as a coating composition for a silicon wafer made of single crystal silicon or polycrystalline silicon, specifically, a photoelectric conversion element made of a silicon wafer.

After coating the coating composition on a silicon wafer, ultraviolet irradiation is performed to cure the ultraviolet curable resin composition, and the silicon wafer is covered with a cured film. The coated silicon wafer is effectively used mainly as a solar cell module serving as a photoelectric conversion device.

Next, a solar cell module using the silicon wafer coating composition of the present invention will be described. The solar cell module can be manufactured, for example, as follows.

First, the coating composition for a silicon wafer of the present invention is applied to a substrate, dried as required, and then irradiated with ultraviolet rays to form a cured film. A photoelectric conversion element is disposed, and the coating composition for a silicon wafer of the present invention is applied again from above the photoelectric conversion element, dried as necessary, and then irradiated with ultraviolet light to form a cured film. I do.

Examples of such a substrate include a glass plate, pottery, other inorganic substances, an aluminum plate, a steel plate, another metal plate, a polymer thermoplastic film, a polymer thermosetting film, and the like.

When a photoelectric conversion element is disposed on a substrate after a cured film is formed on the substrate, before the photoelectric conversion element is disposed, the photoelectric conversion element in contact with the cured film and / or the cured film surface may be used. It is preferable to apply a coating composition for a silicon wafer on the element surface in advance.

When irradiating with ultraviolet light, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp or the like is used as a light source, and 20 to 500 mJ, preferably 100 to 300 mJ.
Irradiation is preferably performed at an integrated irradiation amount of. Irradiation is preferably performed from above and below the photoelectric conversion element.

Thus, a solar cell module having a layer structure of the substrate / the silicon wafer coating agent composition of the present invention / the photoelectric conversion element / the silicon wafer coating agent composition of the present invention can be obtained. Compared to a method in which an adhesive sheet such as a copolymer is melted and evacuated to be pressed and adhered, the workability is extremely excellent and the productivity is improved. In addition, it has a recent V-shaped groove or concave portion. It also has excellent followability with respect to the photoelectric conversion element. In addition, the obtained solar cell module can reduce the light reflectance and is extremely excellent in the power generation conversion efficiency of light energy.

[0040]

The present invention will be specifically described below with reference to examples. In the examples, “%” and “parts” mean on a weight basis unless otherwise specified.

Example 1 Production of urethane acrylate resin (A-1) Air gas was introduced into a reaction vessel equipped with a stirrer, thermometer, cooling pipe and air gas introduction pipe, and then isophorone diisocyanate (manufactured by Huls Co., Ltd .; 9.0 mol of "IPDI") polytetramethylene glycol (manufactured by DuPont)
2.0 mol of “Terratan 650”) and 1.0 mol of polyester triol (molecular weight: 650) (“Adeka New Ace YT-650” manufactured by Asahi Denka Co., Ltd.) were added, and the mixture was heated to 70 ° C. and reacted. Hydroxyethyl acrylate 11.0 mol, hydroquinone monomethyl ether 0.1.
A mixed liquid of 04 parts and 0.01 part of dibutyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., "LIOI") was uniformly dropped over 3 hours to carry out a reaction. After dropping,
After the reaction was continued for about 5 hours, the disappearance of the isocyanate was confirmed, and the reaction was terminated. The urethane acrylate resin (A-1)
(Resin content: 99.5%, weight average molecular weight: 3,5)
00, viscosity: 20,000 mPa · s (60 ° C.), elastic modulus: 6,800 kg / cm ² ).

The obtained urethane acrylate resin (A-
Using 1), a coating composition for a silicon wafer of the present invention was obtained as an ultraviolet-curable resin composition (I-1) having the following composition. -Urethane acrylate resin (A-1) 60 parts (in terms of solid content)-Cyclohexane acrylate (B) 40 parts-Methyl benzoyl formate (C) 3 parts The following evaluation was performed on the silicon wafer coating composition.

(Light Absorbing Property) The obtained coating composition for a silicon wafer was prepared by applying a V-shaped groove to the surface of a silicon wafer made of polycrystalline silicon to form a silicon oxide and titanium oxide layer. It was applied to the surface and passed once under a high-pressure mercury lamp installed at a height of 18 cm from the conveyor belt at a line speed of 5 m / min (integrated light amount of 23 mJ / cm ² ), cured, and cured. 2
0 μm), the absolute density with a black filter was measured using a Macbeth reflection densitometer, and the values were compared to evaluate the light absorption.

Further, a solar cell module comprising a glass substrate / a coating composition for a silicon wafer / a photoelectric conversion element / a coating composition for a silicon was prepared using the obtained coating composition for a silicon wafer. It has good workability and excellent productivity.
The light reflectance was reduced and the power generation conversion efficiency of light was excellent.

Example 2 Production of urethane acrylate resin (A-2) After introducing air gas into a reaction vessel equipped with a stirrer, thermometer, cooling pipe and air gas introduction pipe, isophorone diisocyanate (manufactured by Huls Co., Ltd.) "IPDI") 9.0 mol, polyether diol (molecular weight: 1000) (manufactured by Asahi Denka Co., Ltd., "ADEKA polyether PR-1007") 2.0
Mole, polyether triol (molecular weight 2500) (Adeka Polyether GR-2505, manufactured by Asahi Denka Co., Ltd.)
After charging 1.0 mol and raising the temperature to 70 ° C. to react,
11.0 mol of hydroxyethyl acrylate, 0.04 part of hydroquinone monomethyl ether, and dibutyltin dilaurate (manufactured by Tokyo Fine Chemical Company, "LI
OI ") A reaction was carried out by uniformly dropping 0.01 part of the mixed liquid over 3 hours. After the completion of the dropwise addition, the reaction was continued for about 5 hours. After the disappearance of the isocyanate was confirmed, the reaction was terminated to obtain a urethane (meth) acrylate resin (A-2) (resin content: 98.5%, weight average molecular weight). : 5,500, viscosity:
2,000 mPa · s (60 ° C.), elastic modulus: 230 kg
/ Cm ² ).

The obtained urethane acrylate resin (A-
Using 2), a coating composition for a silicon wafer of the present invention was obtained as an ultraviolet-curable resin composition (I-2) having the following composition. -60 parts of urethane acrylate resin (A-2) (in terms of solid content)-40 parts of 2-hydroxy-3-phenoxypropyl acrylate (B)-3 parts of methylbenzoyl formate (C) About such a coating composition for a silicon wafer The same evaluation as in Example 1 was performed.

Further, a solar cell module comprising a glass substrate / a coating composition for a silicon wafer / a photoelectric conversion element / a coating composition for a silicon was prepared using the obtained coating composition for a silicon wafer. It has good workability and excellent productivity.
The light reflectance was reduced and the power generation conversion efficiency of light was excellent.

Example 3 Production of urethane acrylate resin (A-3) After introducing air gas into a reaction vessel equipped with a stirrer, thermometer, cooling pipe and air gas introduction pipe, trimethylhexamethylene diisocyanate (Takeda Chemical Co., Ltd.) was used. "TMXD
I "), 4.6 mol, and 2.5 mol of polytetramethylene glycol (manufactured by DuPont," Teratan 650 "), and the mixture was heated to 70 [deg.] C. and reacted. Then, 4.5 mol of 2-hydroxyethyl acrylate and hydroquinone were added. 0.04 parts of monomethyl ether and 0.01 of dibutyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., "LIOI")
Part of the mixed liquid was uniformly dropped over 3 hours to carry out a reaction. After the completion of the dropwise addition, the reaction was continued for about 5 hours. After the disappearance of the isocyanate was confirmed, the reaction was terminated to obtain a urethane (meth) acrylate resin (A-3) (resin content: 98.5).
%, Weight average molecular weight: 6,700, viscosity: 6,000 m
Pa · s (60 ° C.), elastic modulus: 110 kg / cm ² ).

The obtained urethane acrylate resin (A-
Using 3), a UV curable resin composition (I-3) having the following composition was obtained to obtain a coating composition for a silicon wafer of the present invention. -60 parts of urethane acrylate resin (A-3) (in terms of solid content)-40 parts of cyclohexyl acrylate (B)-3 parts of methylbenzoyl formate (C) 3 evaluations of the coating composition for a silicon wafer as in Example 1. Was done.

A solar cell module comprising a glass substrate / a coating composition for a silicon wafer / a photoelectric conversion element / a coating composition for a silicon was prepared using the obtained coating composition for a silicon wafer. It has good workability and excellent productivity.
The light reflectance was reduced and the power generation conversion efficiency of light was excellent.

Example 4 Production of urethane acrylate resin (A-4) After introducing air gas into a reaction vessel equipped with a stirrer, thermometer, cooling pipe and air gas introduction pipe, trimer of hexamethylene diisocyanate was prepared. (Containing isocyanurate ring)
(Manufactured by Nippon Polyurethane Co., "Coronate HX") 1.0
After charging the mol and raising the temperature to 70 ° C., 3.05 mol of 2-hydroxypropyl acrylate, 0.04 part of hydroquinone monomethyl ether, and dibutyltin dilaurate (“LIOI” manufactured by Tokyo Fine Chemical Co., Ltd.)
A reaction was carried out by uniformly dropping 0.01 part of the mixed liquid over 3 hours. After the completion of the dropwise addition, the reaction was continued for about 5 hours. Then, the disappearance of the isocyanate was confirmed and the reaction was terminated to obtain a urethane (meth) acrylate resin (A-4) (resin content: 9).
9.2%, weight average molecular weight: 2,400, viscosity: 13,
000mPa · s (60 ° C), elastic modulus: 20,000k
g / cm ² ).

The obtained urethane acrylate resin (A-
Using 4), a UV-curable resin composition (I-4) having the following composition was obtained to obtain a coating composition for a silicon wafer of the present invention. -Urethane acrylate resin (A-4) 60 parts (in terms of solid content)-Cyclohexyl acrylate (B) 40 parts-Methyl benzoyl formate (C) 3 parts The same evaluation as in Example 1 for such a coating composition for silicon wafers. Was done.

A solar cell module comprising a glass substrate / a coating composition for a silicon wafer / a photoelectric conversion element / a coating composition for a silicon was prepared using the obtained coating composition for a silicon wafer. It has good workability and excellent productivity.
The light reflectance was reduced and the power generation conversion efficiency of light was excellent.

Example 5 The urethane acrylate resin obtained in Example 4 (A-
Using 4), a UV curable resin composition (I-5) having the following composition was obtained to obtain a coating composition for a silicon wafer of the present invention. -Urethane acrylate resin (A-4) 70 parts (in terms of solid content)-2-hydroxy-3-phenoxypropyl acrylate (B) 30 parts-Methylbenzoyl formate (C) 3 parts Regarding such a coating composition for a silicon wafer. The same evaluation as in Example 1 was performed.

Further, a solar cell module comprising a glass substrate / a coating composition for a silicon wafer / a photoelectric conversion element / a coating composition for a silicon was prepared using the obtained coating composition for a silicon wafer. It has good workability and excellent productivity.
The light reflectance was reduced and the power generation conversion efficiency of light was excellent.

Comparative Example 1 A V-shaped groove was formed on the surface of a silicon wafer made of polycrystalline silicon, and the photoelectric conversion element having the silicon oxide and titanium oxide layers formed thereon was not coated with the coating composition for a silicon wafer. The light absorption was measured using a reflection densitometer.

COMPARATIVE EXAMPLE 2 A V-shaped groove was formed on the surface of a silicon wafer made of polycrystalline silicon, and an ethylene-vinyl acetate copolymer adhesive sheet (Mitsui "Evaflex P" manufactured by DuPont Polychemicals
−2805 ”), and then heat the adhesive sheet by applying a temperature of about 100 ° C., and at the same time, apply a vacuum and then press to laminate, and further crosslink the ethylene-vinyl acetate copolymer. For this purpose, a heat treatment at about 140 to 150 ° C. was performed to form a coating layer of 20 μm. Next, the light absorption was measured using a Macbeth densitometer. Table 1 shows the results of Examples and Comparative Examples.

[0058]

[Table 1]

[0059]

Industrial Applicability The coating composition for silicon wafers of the present invention has excellent followability to a finely processed surface of a photoelectric conversion element comprising a silicon wafer, excellent workability, and further reduces light reflectance. It also has an excellent effect on the power generation conversion efficiency of light energy, and is very effective in manufacturing a solar cell module.

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[Procedure amendment]

[Submission Date] August 8, 2000 (200.8.8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

Further, as the polyol (a1) component, a diol component and a triol component are added in 20 / 80-80.
/ 20 (weight ratio). More preferably, diol component / triol component = 40/60.
-75/25 (weight ratio), particularly preferably diol component / triol component = 60 / 40-70 / 30 (weight ratio).
It is. If the ratio is less than 20/80, the curing shrinkage during curing by irradiation with ultraviolet rays becomes large, so that warpage or cracking of the cured product is liable to occur, and the adhesion to the member is significantly reduced. The curability due to ultraviolet irradiation is reduced, and a cured product having a surface tack of the cured product is obtained, which is not preferable.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction contents]

(Light Absorbing Property) The obtained coating composition for a silicon wafer was prepared by applying a V-shaped groove to the surface of a silicon wafer made of polycrystalline silicon to form a silicon oxide and titanium oxide layer. Coated on the surface, passed once under a high-pressure mercury lamp installed at a height of 18 cm from the conveyor belt at a line speed of 5 m / min (total light amount: 230 mJ / cm ² ), cured, and cured. (20 μm) was formed, the absolute density was measured with a black filter using a Macbeth reflection densitometer, and the values were compared to evaluate the light absorbency.

Continued on the front page F-term (reference) 4J038 DG051 DG052 DG081 DG082 DG111 DG112 DG131 DG132 DG191 DG192 DG271 DG272 DG281 DG282 DG291 DG292 FA121 FA122 FA131 FA132 FA141 FA142 FA151 FA152 FA161 FA162 GA02 JC31 JC03 J0631 AA02 CA05 DB17 EA10 EB02 EB04 EB18 ED04 EE12 GA01 5F051 AA02 EA01 EA18 EA20 GA04 GA06 HA04

Claims (8)

[Claims] 1. Silicon comprising a UV-curable resin composition (I) containing a urethane (meth) acrylate resin (A), a reactive diluent (B) and a photopolymerization initiator (C). Coating composition for wafer. 2. The urethane (meth) acrylate resin (A) has a weight average molecular weight in terms of standard polystyrene molecular weight of 1,000 to 30,000 and a glass transition temperature of 250 ° C. or less. The coating agent composition for a silicon wafer according to the above. 3. The coating agent for a silicon wafer according to claim 1, wherein the number of (meth) acryloyl groups per molecule of the urethane (meth) acrylate resin (A) is 2 to 6. Composition. 4. The reactive diluent (B) is used in an amount of 1 to 1 per molecule.
The coating composition for silicon according to any one of claims 1 to 3, having five ethylenically unsaturated groups. 5. A urethane (meth) acrylate resin (A) and a reactive diluent (B) having a total amount of 30 to 90% by weight of the urethane (meth) acrylate resin (A), The coating composition for a silicon wafer according to any one of claims 1 to 4, comprising 10 to 70% by weight of B). 6. The coating composition for a silicon wafer according to claim 1, further comprising a silane compound (D). 7. A solar cell module comprising a photoelectric conversion element coated with the coating composition for a silicon wafer according to any one of claims 1 to 6. 8. The solar cell module according to claim 7, wherein the solar cell module has a layer structure of substrate / coating agent composition for silicon wafer / photoelectric conversion element / coating agent composition for silicon wafer.