JP6083250B2 - Easy-adhesive composition, laminated polyester resin film, and solar battery back sheet - Google Patents

Description

The present invention relates to an easy-adhesive composition, a laminated polyester resin film, and a solar battery back sheet.

In recent years, from the viewpoint of effective use of resources and prevention of environmental pollution, solar cells that convert sunlight into electric energy have attracted attention and are being actively developed. This solar cell is generally an EVA (ethylene-vinyl acetate copolymer) film between a glass substrate as a light-receiving surface-side transparent protective member and a back-side protective member (back sheet), such as a silicon power generation element. The cell is sealed. These constituent materials are laminated in the order of the light-receiving side transparent protective member, the sheet-shaped sealing resin disposed on the front surface side, the solar cell, the sheet-shaped sealing resin disposed on the back surface side, and the back sheet, A solar cell module is formed by heating and vacuum lamination.
In addition, since solar cells are used outdoors, the members used are required to have high durability, weather resistance, light resistance, and the like. In particular, the backsheet withstands long-term exposure to sunlight, temperature fluctuations during the day and night, wind pressure and mechanical deformation during construction, and is free from contaminants such as moisture, oxygen, nitrogen oxides, and sulfur oxides. It is required to prevent intrusion and protect the power generating element.
Examples of such materials include polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, and ethylene / tetrafluoroethylene copolymer. In many cases, fluorine resin sheets, metal foils, and the like are used in combination. However, the fluororesin sheet is expensive, and at the same time, it is not sufficient from the viewpoint of durability in the long-term high-voltage application of the power generation module, and various structures have been proposed as improved techniques.
Therefore, in recent years, studies have been made to use general-purpose plastic sheets such as polypropylene films and polyethylene terephthalate films (hereinafter referred to as PET films) as back sheets. However, general-purpose plastic sheets have a problem in light resistance or adhesion to EVA, which is used as a standard as a sealing resin. Therefore, inorganic particles are added to the plastic sheet itself to increase light resistance, Studies have been made to improve adhesion by providing an easy-adhesion layer with EVA. (Patent Documents 1 to 4)
However, in the methods described in Patent Documents 1 to 4, the adhesion with EVA is insufficient and it cannot be said that satisfactory performance has been achieved. In addition, in order to increase the adhesion to EVA, it is preferable to use a binder resin having a low glass transition temperature as the easy-adhesive composition. However, such a binder resin, on the contrary, deteriorates the blocking resistance. End up. On the other hand, studies have been made to include a pigment in the easy-adhesive composition for the purpose of enhancing the power generation efficiency, imparting performance such as weather resistance and light resistance. However, in the conventional easy-adhesive composition, when a pigment is contained, the adhesiveness with EVA is extremely lowered, and further, the storage stability as an easy-adhesive also has a problem. Moreover, when using the plastic sheet which is easy to receive hydrolysis, such as PET film, as a base material of a back sheet, the hydrolysis resistance which suppresses hydrolysis is requested | required also for an easily adhesive. Then, development of the easily adhesive composition, laminated polyester resin film, and solar cell backsheet which solve these subjects is desired.

JP 2011-018872 A JP 2006-320991 A JP 2009-246360 A Japanese Patent No. 4807473

Accordingly, the object of the present invention is to provide adhesion to EVA, blocking resistance, weather resistance, light resistance, storage stability, and further hydrolysis resistance by coating various commercially available PET films. It is to provide an easy-adhesive composition that can be produced.

In order to solve the above problems, the present inventor has made extensive studies, and as a result, the resin containing a hydroxyl group selected from an acrylic resin and a polyester resin, and a composition containing a polyisocyanate compound have good compatibility with the resins. The present inventors have found that the above-mentioned problems can be solved by adding a modified polyolefin into which a carboxyl group or a hydroxyl group is introduced .

That is, the present invention is selected from acrylic resins and polyester resins, resin hydroxyl value containing a hydroxyl group is 1~200mgKOH / g (A), polyisocyanate compound (B), modified polyolefin obtained by introducing a carboxyl group or a hydroxyl group An easy-adhesive composition containing (C), a laminated film obtained by laminating the composition, a solar battery back sheet, and a solar battery comprising the film as a constituent component are provided.

  According to the easy-adhesive composition of the present invention, an easy-adhesive composition capable of imparting adhesiveness to EVA, blocking resistance, weather resistance, light resistance, storage stability, and further hydrolysis resistance is used. The solar battery backsheet that was present can be provided.

The resin (A) having a hydroxyl group used in the present invention, if the hydroxyl value of the resin is 1~200mgKOH / g, but not limited to, for example, an acrylic resin, each having a hydroxyl group, a polyester resin, which are It may be used alone or in combination of two or more.

  The resin (A) containing a hydroxyl group used in the present invention has a hydroxyl value satisfying 1 to 200 mgKOH / g, and particularly having a hydroxyl value in the range of 4 to 100 mgKOH / g, adhesion to EVA and durability. From the viewpoint of hydrolysis resistance. When the hydroxyl value is less than 1, curing of the coating film hardly progresses, and adhesion and durability with EVA are inferior. On the other hand, when the hydroxyl value is larger than 200, the curing shrinkage is too large, so that the adhesion with EVA is deteriorated.

  The acrylic resin containing a hydroxyl group used in the present invention refers to a linear resin containing a hydroxyl group obtained by polymerizing an acrylic ester or a methacrylic ester as an essential component. Hereinafter, acrylic and methacryl are collectively referred to as (meth) acryl.

  Such an acrylic resin can be easily obtained, for example, by copolymerizing a carboxylic acid group-containing monomer such as (meth) acrylic acid, itaconic acid, maleic anhydride, etc. as necessary with (meth) acrylic acid ester as an essential component. Can be manufactured. Examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and tert-butyl. (Meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, isobornyl (meth) acrylate Etc.

  In carrying out copolymerization using (meth) acrylic acid ester as an essential component, for example, hydroxyl-containing (meth) acrylic acid ester such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, etc. By using together, the hydroxyl-containing (meth) acrylic resin by which the hydroxyl group was introduce | transduced into the side chain of the acrylic resin frame | skeleton can be obtained.

  An acrylic resin containing such a hydroxyl group has an ethylene glycol di () content in the above-mentioned monomer within a range that does not greatly impair characteristics such as low viscosity due to being linear and excellent flexibility of the cured film. It is an acrylic resin that is polymerized with a small amount of 2-6 (meth) acryloyl group-containing polymerizable monomers such as (meth) acrylate, trimethylolpropane tri (meth) acrylate, and hexa (meth) acrylate. There may be.

  Examples of such an acrylic resin containing a hydroxyl group include “Acridic” series manufactured by DIC Corporation and “Aclit” series manufactured by Taisei Fine Chemical Co., Ltd. For example, as a commercial item of an acrylic resin, DIC Corporation make, brand name: ACRYDIC A-808-T, 57-451 can be mentioned.

  The polyester resin containing a hydroxyl group used in the present invention refers to a linear resin containing an excess hydroxyl group obtained by reacting glycol with dibasic acid or a derivative thereof as essential components. Of course, in place of the dibasic acid, an ester-forming derivative such as a dibasic acid anhydride or a dibasic acid lower alkyl ester is used, and not only in a polycondensation reaction, but also in an addition reaction or a transesterification reaction, a polyester resin Can also be obtained.

  Examples of the polyester resin include aliphatic glycols such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, decanediol, and cyclohexanedimethanol, and succinic acid, adipic acid, sebacic acid, and suberin fumarate. Aliphatic polyester resins obtained by reacting acid, azelaic acid, aliphatic dibasic acid such as 1,10-decamethylenedicarboxylic acid and cyclohexanedicarboxylic acid as essential raw material components, and fats such as ethylene glycol, propylene glycol and butanediol An aromatic polyester resin obtained by reacting an aromatic glycol with an aromatic dibasic acid such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid or the like as an essential raw material component can be given.

  Such a hydroxyl group-containing polyester resin has a trimerit to glycols and dibasic acids as long as the characteristics such as low viscosity and excellent flexibility of the cured film are not greatly impaired. Even a polyester resin obtained by using a small amount of a compound containing 3 to 4 active hydrogen groups such as hydroxyl group or carboxy group such as acid, pyromellitic acid, tromethylolpropane and pentaerythritol in the molecule good.

  The polyester resin tends to have a higher Tg by containing more benzene rings and naphthalene rings in the main chain. For example, the target substrate to be coated is PET, PBT (polybutylene terephthalate), Since affinity with PEN (polyethylene naphthalate) increases, it is preferable to use an aromatic polyester resin rather than an aliphatic polyester resin in the present invention. However, since more benzene rings and naphthalene rings are contained in the main chain, crystallinity, melting point, etc. tend to increase, and fluidity and applicability tend to be lowered.

  Therefore, the polyester resin is preferably a polyester resin having a glass transition temperature (Tg) of 20 to 110 ° C. according to differential scanning calorimetry (DSC method). In the present invention, Tg of 40 to 100 obtained by using 25 mol% or more of aliphatic glycol having 2 to 4 carbon atoms in all alcohols and 30 mol% or more of aromatic dibasic acid in all polybasic acids. It is more preferable to use an aromatic polyester resin at ° C.

  Examples of the polyester resin containing a hydroxyl group include “Byron” series manufactured by Toyobo Co., Ltd., “Eritel” series manufactured by Unitika Ltd., and more specifically, for example, manufactured by Unitika Ltd., trade name: Elitel UE-3210. XA-0611.

The resin (A) containing a hydroxyl group used in the present invention satisfies the number average molecular weight of 5,000 to 50,000, preferably the number average molecular weight is 10,000 to 30,000. , More preferable in terms of excellent hydrolysis resistance. The above-described resin containing a hydroxyl group having a molecular weight dissolves in an organic solvent, and exhibits outstanding adhesion to EVA and hydrolysis resistance without significantly impairing the fluidity of the solution.

  The resin (A) containing a hydroxyl group used in the present invention satisfies a glass transition temperature of 20 to 110 ° C. in order to form a coating film having excellent adhesion on a flexible substrate such as a plastic film. In particular, the glass transition temperature is more preferably 40 to 100 ° C. The above-described resin containing a hydroxyl group having a glass transition temperature can satisfy a good balance of EVA adhesion, blocking resistance, and hydrolysis resistance.

  Examples of the polyisocyanate compound (B) used in the present invention include organic compounds having at least two isocyanate groups in the molecule. Examples of the organic 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- (isocyanatomethyl) cyclohexane, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate; adducts of these polyisocyanates, burettes of these polyisocyanates, or these polyisocyanates And polyisocyanate derivatives (modified products) such as isocyanurates.

The polyisocyanate compound (B) used in the present invention may be appropriately selected depending on the application to be used, but an aromatic system such as tolylene diisocyanate may turn yellow and requires better weather resistance. Is preferably an aliphatic or alicyclic non-yellowing polyisocyanate. It is not preferable that the cured coating film is colored on a transparent substrate such as a polyester resin film and the transparency is lowered in view of deterioration of visibility. Therefore, it is preferable to use non-yellowing polyisocyanates such as aliphatic or alicyclic non-yellowing polyisocyanates such as hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI).
The curing agent exhibits a certain level of performance only with the polyisocyanate compound (B), but imparts a high degree of hydrolysis resistance to the cured coating by actively using the polyisocyanate compound and the epoxy resin described below. I can do it.

  The mixing ratio of the hydroxyl group-containing resin (A) and the polyisocyanate compound (B) is such that the hydroxyl group-containing resin (A) solid content hydroxyl equivalent (a) and the polyisocyanate compound (B) solid isocyanate equivalent The equivalent ratio [(a) / (b)] of (b) is 0.5 to 5, preferably 0.6 to 2.0.

The modified polyolefin (C) used in the present invention is not particularly limited as long as it is compatible with the other components of the composition of the present invention, and examples thereof include resins described later .
Among these resins, those having a polar group described later and having a polyolefin skeleton are preferable .

The polar groups, e.g., hydroxyl group and a carboxyl group.

Modified polyolefin (C) used in the present invention, as described above, the polyolefin resin, for example, a carboxyl group, modified polyolefin resin obtained by introducing a hydroxyl group is more preferable. Further, among these modified polyolefin resins, the adhesion of the metal layer is further improved and the electrolyte resistance is excellent. Therefore, a modified polyolefin resin having an acid value of 1 to 200 mgKOH / g (hereinafter referred to as an acid-modified polyolefin resin). And / or a modified polyolefin resin having a hydroxyl value of 1 to 200 mgKOH / g (hereinafter referred to as a hydroxyl group-modified polyolefin resin) is more preferred.

  The acid-modified polyolefin resin is a polyolefin resin having a carboxyl group or a carboxylic anhydride group in the molecule, and is synthesized by modifying the polyolefin with an unsaturated carboxylic acid or a derivative thereof. As this modification method, graft modification or copolymerization can be used.

  The acid-modified polyolefin resin is a graft-modified polyolefin obtained by graft-modifying or copolymerizing at least one polymerizable ethylenically unsaturated carboxylic acid or a derivative thereof on a polyolefin resin before modification. Examples of the polyolefin resin before modification include the above-described polyolefin resins. Among them, a homopolymer of propylene, a copolymer of propylene and an α-olefin, a homopolymer of ethylene, and a copolymer of ethylene and an α-olefin. Polymers are preferred. These can also be used individually by 1 type and can also be used in combination of 2 or more type.

  Examples of the ethylenically unsaturated carboxylic acid or a derivative thereof to be graft-modified or copolymerized with the polyolefin resin before modification include acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, maleic anhydride, 4- Methylcyclohex-4-ene-1,2-dicarboxylic anhydride, bicyclo [2.2.2] oct-5-ene-2,3-dicarboxylic anhydride, 1,2,3,4,5, 8,9,10-octahydronaphthalene-2,3-dicarboxylic anhydride, 2-octa-1,3-diketospiro [4.4] non-7-ene, bicyclo [2.2.1] hept-5 -Ene-2,3-dicarboxylic anhydride, maleopimaric acid, tetrahydrophthalic anhydride, methyl-bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic acid Objects, methyl - norbornene-5-ene-2,3-dicarboxylic anhydride, and the like norborn-5-ene-2,3-dicarboxylic anhydride. Preferably maleic anhydride is used. These can be used alone or in combination of two or more.

  Various methods can be employed for grafting a graft monomer selected from an ethylenically unsaturated carboxylic acid or a derivative thereof onto a polyolefin resin before modification. For example, a method in which a polyolefin resin is melted and a graft monomer is added thereto to cause a graft reaction, a method in which a polyolefin resin is dissolved in a solvent to form a solution and a graft monomer is added thereto to cause a graft reaction, and a solution is dissolved in an organic solvent. Examples thereof include a method in which a polyolefin resin is mixed with the unsaturated carboxylic acid and the like, heated at a temperature equal to or higher than the softening temperature or melting point of the polyolefin resin, and simultaneously subjected to radical polymerization and hydrogen abstraction reaction in a molten state. In any case, in order to efficiently graft copolymerize the graft monomer, it is preferable to carry out the grafting reaction in the presence of a radical initiator. The grafting reaction is usually performed under conditions of 60 to 350 ° C. The ratio of the radical initiator used is usually in the range of 0.001 to 1 part by weight with respect to 100 parts by weight of the polyolefin resin before modification.

  The radical initiator is preferably an organic peroxide, such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (peroxidebenzoate) hexyne-3, 1,4-bis (tert-butylperoxyisopropyl) benzene, lauroyl peroxide, tert-butylperacetate, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 2,5-dimethyl- 2.5-di (tert-butylperoxy) hexane, tert-butylperbenzoate, tert-butylperphenylacetate, tert-butylperisobutyrate, tert-butylper-sec-octoate, tert-butyl Ruperupibareto and cumyl perpivalate and tert- butyl hydroperoxide diethyl acetate. Other azo compounds such as azobisisobutyronitrile and dimethylazoisobutyrate can also be used.

  These radical initiators should be selected optimally depending on the process of the grafting reaction, but usually dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (tert- Dialkyl peroxides such as butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (tert-butylperoxy) hexane and 1,4-bis (tert-butylperoxyisopropyl) benzene are preferably used.

  Examples of these acid-modified polyolefin resins include maleic anhydride-modified polypropylene, ethylene- (meth) acrylic acid copolymer, ethylene-acrylic acid ester-maleic anhydride terpolymer, or ethylene-methacrylic acid ester- A maleic anhydride terpolymer may be mentioned. Specifically, “Modic” manufactured by Mitsubishi Chemical Corporation, “Admer” manufactured by Mitsui Chemicals, Inc., “Unistal”, “Toyo Tac” manufactured by Toyo Kasei Co., Ltd., “Yumex” manufactured by Sanyo Chemical Co., Ltd. , "Lex Pearl EAA" "Lex Pearl ET" manufactured by Nippon Polyethylene Co., Ltd., "Primacol" manufactured by Dow Chemical Co., Ltd., "Nuclele" manufactured by Mitsui DuPont Polychemical Co., Ltd. .

  The hydroxyl group-modified polyolefin resin is a polyolefin resin having a hydroxyl group in the molecule, and is synthesized by graft modification or copolymerization of a polyolefin with a hydroxyl group-containing (meth) acrylic acid ester or a hydroxyl group-containing vinyl ether described later. The polyolefin resin before modification and the modification method are the same as in the case of acid-modified polyolefin resin.

  The modified polyolefin containing a hydroxyl group used in the present invention is synthesized by graft-modifying or copolymerizing a polyolefin resin with a hydroxyl group-containing (meth) acrylic ester described later or a hydroxyl group-containing vinyl ether. At this time, at least a part of the polyolefin structure may have a fluorinated structure.

  Examples of the polyolefin resin include homopolymers and copolymers of olefins having 2 to 8 carbon atoms, and copolymers of olefins having 2 to 8 carbon atoms and other monomers. Specifically, for example, high density polyethylene (HDPE), low density polyethylene (LDPE), polyethylene such as linear low density polyethylene resin, polypropylene, polyisobutylene, poly (1-butene), poly-4-methylpentene, polyvinyl Cyclohexane, polystyrene, poly (p-methylstyrene), poly (α-methylstyrene), ethylene / propylene block copolymer, ethylene / propylene random copolymer, ethylene / butene-1 copolymer, ethylene / 4-methyl -1-pentene copolymer, α-olefin copolymer such as ethylene / hexene copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / methyl methacrylate copolymer, ethylene / Vinyl acetate methyl methacrylate copolymer, Aio Examples thereof include nomer resins. Furthermore, chlorinated polyolefins obtained by chlorinating these polyolefins, fluorinated polyolefins obtained by fluorination, and the like can also be used.

  Examples of the hydroxyl group-containing (meth) acrylic acid ester include hydroxyethyl (meth) acrylate; hydroxypropyl (meth) acrylate, glycerol (meth) acrylate; lactone modified hydroxyethyl (meth) acrylate, (meth) acrylic acid. Examples include polyethylene glycol and polypropylene glycol (meth) acrylic acid, and examples of the hydroxyl group-containing vinyl ether include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, and 4-hydroxybutyl vinyl ether.

  As the polyolefin resin containing these hydroxyl groups, for example, “Unistol” manufactured by Mitsui Chemicals, Inc. is commercially available.

Value entered The weight ratio of the modified polyolefin (C) is 0.1 to 200 parts by weight, particularly 1 to 50 parts by weight, based on 100 parts by weight (solid content) of the resin (A) containing a hydroxyl group. It is more preferable to have excellent adhesion to EVA, weather resistance, storage stability, and the like.

  The composition of this invention may use a pigment (D) together as needed. In this case, usable pigments are not particularly limited. For example, extender pigments, white pigments, black pigments, gray pigments, red pigments described in the Paint Material Handbook 1970 edition (edited by the Japan Paint Industry Association) Examples thereof include organic pigments and inorganic pigments such as pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminescent pigments, and pearl pigments, and plastic pigments. Specific examples of these colorants include various types, and examples of organic pigments include various insoluble azo pigments such as Bench Gin Yellow, Hansa Yellow, Raked 4R, etc .; Soluble properties such as Raked C, Carmine 6B, Bordeaux 10 and the like. Azo pigments;

Various (copper) phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; various chlorine dyeing lakes such as rhodamine lake and methyl violet lake; various mordant dye pigments such as quinoline lake and fast sky blue; anthraquinone pigment; Various vat dyes such as thioindigo pigments and perinone pigments; various quinacridone pigments such as Cincacia Red B; various dioxazine pigments such as dioxazine violet; various condensed azo pigments such as chromoftal; aniline Black etc. are mentioned.

  Examples of inorganic pigments include various chromates such as chrome lead, zinc chromate, and molybdate orange; various ferrocyan compounds such as bitumen; titanium oxide, zinc white, mapico yellow, iron oxide, bengara, chrome oxide Various metal oxides such as green and zirconium oxide; various sulfides or selenides such as cadmium yellow, cadmium red and mercury sulfide;

Various sulfates such as barium sulfate and lead sulfate; Various silicates such as calcium silicate and ultramarine blue; Various carbonates such as calcium carbonate and magnesium carbonate; Various phosphates such as cobalt violet and manganese purple; Aluminum Various metal powder pigments such as powder, gold powder, silver powder, copper powder, bronze powder and brass powder; flake pigments of these metals, mica flake pigments; mica flake pigments coated with metal oxides, mica-like iron oxide Examples thereof include metallic pigments such as pigments and pearl pigments; graphite and carbon black.

  Examples of extender pigments include precipitated barium sulfate, powder, precipitated calcium carbonate, calcium bicarbonate, cryolite, alumina white, silica, hydrous finely divided silica (white carbon), ultrafine anhydrous silica (Aerosil), and silica sand (silica). Sand), talc, precipitated magnesium carbonate, bentonite, clay, kaolin, ocher and the like.

  Furthermore, examples of the plastic pigment include DIC Corporation Grandol PP-1000, PP-2000S, and the like.

  As the pigment (D), since it is excellent in durability, weather resistance, and design, inorganic oxides such as titanium oxide and zinc white as a white pigment, and carbon black as a black pigment are more preferable. In addition, when using pigments, you may use a pigment dispersant together.

  The weight ratio of the pigment (D) is 1 to 400 parts, particularly 10 to 300 parts, with respect to 100 parts of the resin (A) containing a hydroxyl group. Adhesion with EVA, weather resistance, storage stability It is more preferable because of its excellent properties.

  An epoxy resin may be used in combination with the composition of the present invention for the purpose of imparting higher hydrolysis resistance. Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and bisphenol AD type epoxy resin; orthocresol novolac type epoxy resin, phenol novolac type epoxy Resin, naphthol novolac epoxy resin, bisphenol A novolac epoxy resin, brominated phenol novolac epoxy resin, alkylphenol novolac epoxy resin, bisphenol S novolac epoxy resin, alkoxy group-containing novolac epoxy resin, brominated phenol novolac epoxy Novolac type epoxy resin such as resin; other phenol aralkyl type epoxy resin ), Diglycidyl ether of resorcin, diglycidyl ether of hydroquinone, diglycidyl ether of catechol, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, sulfur-containing epoxy resin, stilbene type epoxy resin, etc., Alicyclic epoxy resin such as hydrogenated bisphenol A type epoxy resin, triglycidyl isocyanurate, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, biphenyl modified novolak type Epoxy resins (epoxidized products of polyphenol resins in which phenol nuclei are linked by bismethylene groups), alkoxy group-containing novolac type epoxy resins, tetrabromobisphenol A type epoxy resins Such as resin and the like. Moreover, the said epoxy resin may be used independently and may mix 2 or more types.

  From the viewpoint of viscosity adjustment, the easy-adhesive composition of the present invention, particularly the main agent described above, may contain an organic solvent that does not have reactivity with the raw materials included therein and dissolves the raw materials. Specifically, for example, hydrocarbon solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and butyl acetate, ether solvents such as dioxane and ethylene glycol diethyl ether , Aliphatic hydrocarbons such as pentane, hexane and heptane.

  If necessary, the easy-adhesive composition of the present invention may contain other additives other than those described above. Examples of the additive include additives generally used in resin compositions that form films and coating films. 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; viscosity modifiers; Metal deactivator; Peroxide decomposing agent; Flame retardant; Reinforcing agent; Plasticizer; Lubricant; Rust preventive agent; Fluorescent whitening agent; Inorganic heat absorber; Flameproof agent; And so on.

  The easy-adhesive composition of the present invention is usually prepared by preparing a main component premix in which components other than the polyisocyanate compound that is a curing agent are blended in advance, and mixing this with the polyisocyanate compound. I can do it.

The easy-adhesive composition of this invention can laminate | stack a hardened coating film with adhesiveness on a base material by apply | coating to various base materials and drying. The amount of application to the substrate is not particularly limited, but for example, it is selected from the range of 0.5 to 20 g / m ² , especially 1 to 10 g / m ^2. It is preferable at the point which can provide. For this coating, for example, a gravure coater, a micro gravure coater, a reverse coater, a bar coater, a roll coater, a die coater or the like can be used.

  Moreover, it is preferable that the laminated body which apply | coated the easily adhesive composition of this invention performs aging after preparation. The aging conditions are from room temperature to 100 ° C. and for 12 to 240 hours, during which the curing reaction proceeds.

  Examples of the base material in this case include paper, olefin resin, acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, fluorine resin, poly (meth) acrylic resin, and carbonate resin. And polyamide resin, polyimide resin, polyphenylene ether resin, synthetic resin film obtained from polyphenylene sulfide resin and polyester resin, copper foil, metal foil such as aluminum foil, and the like. The thickness of the substrate is not particularly limited, and can be selected from, for example, 10 to 400 μm. However, the easy-adhesive composition of the present invention can be applied to a substrate with a small amount of application and low-temperature and short-time drying. Since it exhibits excellent adhesion without giving any influence such as sag and can provide excellent weather resistance, it is most suitable to be applied to a substrate having a softening temperature of 180 ° C. or less at 30 to 80 μm.

  Low-temperature and short-time drying eliminates the inconvenience of warping the substrate and peeling the coating film, and provides excellent adhesion to the substrate, preventing deterioration of the laminate more effectively. It is preferable to use a polyester resin film as the base material because it can be used. The laminated polyester resin film in which the cured coating film of the easy-adhesive composition of the present invention is laminated on the polyester resin film has the above-described excellent properties.

  In particular, from the drying at a relatively low temperature of 160 ° C. or less for a short time of 1 minute or less, the above-mentioned inconvenience is not caused to the thin film base material, and excellent adhesion to the base material is obtained, and the moisture resistance of the laminated body is obtained. As a base material, it is more preferable to use a PET film in that deterioration based on heat resistance and hydrolysis resistance can be more effectively prevented. The laminated polyester resin film in which the cured coating film of the easy-adhesive composition of the present invention is laminated on a PET film has the above-described excellent properties. In particular, it is suitable as a laminated polyester resin film for a solar battery backsheet.

  In order to improve the adhesion between the polyester resin film and the cured coating film, a surface treatment may be performed on the surface on which the cured coating film of the polyester resin film is formed. Examples of the surface treatment include corona treatment, plasma treatment, ozone treatment, flame treatment, and radiation treatment.

In the solar cell module of the present invention, the configuration of the transparent protective member, the solar cell, the sealing resin that covers the entire surface of the solar cell, and the back sheet is the same as that of a conventionally known solar cell module. This is not a configuration specific to the present invention.

  That is, as a cell for solar cells, a transparent electrode layer, an optical semiconductor layer, and a back electrode layer are laminated on a substrate and separated by separation grooves so as to form a plurality of photoelectric conversion cells, and these photoelectric conversion cells are An integrated solar cell element electrically connected in series is generally used, and silicon, thin-film polycrystalline silicon, or the like can be used as the photoelectric conversion layer in the optical semiconductor layer. Furthermore, an electrical output can be taken out of the module from the solar cell.

  As the resin used as the sealing resin, EVA is mainly used, but PVB (polyvinyl butyral), PIB (polyisobutylene), olefin resin (especially graft-modified polyethylene resin), ionomer resin, silicon resin, etc. may be used. it can. Usually, EVA used as a sealing resin for a solar cell module has a vinyl acetate content of 10 to 40% by weight, and heat or light is used to ensure the heat resistance and physical strength of the solar cell module. EVA is cross-linked by the above.

  In the case of performing thermal crosslinking, an organic peroxide is usually used, and one that decomposes at a temperature of 70 ° C. or higher to generate radicals is used. Usually, those having a decomposition temperature of 50 ° C. or more with a half-life of 10 hours are used, and 2,5-dimethylhexane-2,5-dihydroxyperoxide, 2,5-dimethyl-2,5-di (t-butyl) Peroxy) hexyne-3, di-t-butyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, dicumyl peroxide, α, α '-Bis (t-butylperoxyisopropyl) benzene, n-butyl-4,4-bis- (t-butylperoxy) valerate, t-butylperoxybenzoate, benzoyl peroxide and the like are used.

  In the case of photocuring, a photosensitizer is used, and hydrogen abstraction type (bimolecular reaction type) such as benzophenone, methyl orthobenzoylbenzoate, 4-benzoyl-4′-methyldiphenyl sulfide, isopropylthioxanthone, etc. As the internal cleavage type initiator, α-hydroxyalkylphenone type such as benzoin ether, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl, etc. Phenyl ketone, alkylphenyl glyoxylate, diethoxyacetophenone and the like can be used. Further, as α-aminoalkylphenone type, 2-methyl-1- [4 (methylthio) phenyl] -2-morpholinopropane-1, 2-benzyl-2-dimethylamino-1- (4-morpholino) Phenyl) -butanone-1 and the like, and acylphosphine oxide and the like are also used.

  A silane coupling agent is also blended in consideration of adhesion to the glass plate constituting the solar cell module, and vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, Vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane , Γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, and the like.

  Furthermore, an epoxy group-containing compound may be blended for the purpose of promoting adhesion and curing. Examples of the epoxy group-containing compound include triglycidyl tris (2-hydroxyethyl) isocyanurate, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, acrylic glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, phenol glycidyl ether, pt-butylphenyl glycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester , Glycidyl methacrylate, butyl glycidyl ether and other compounds, oligomers containing an epoxy group with a molecular weight of several hundred to several thousand, and polymers with a weight average molecular weight of several thousand to several hundred thousand. Some cases are there.

Further, an acryloxy group, methacryloxy group or allyl group-containing compound is added for the purpose of improving the crosslinking resin, adhesion, mechanical strength, heat resistance, heat and humidity resistance, weather resistance, etc. Acrylic acid derivatives such as their alkyl esters and amides are most common. In this case, as the alkyl group, in addition to an alkyl group such as methyl, ethyl, dodecyl, stearyl, lauryl, cyclohexyl group, tetrahydrofurfuryl group, aminoethyl group, 2-hydroxyethyl group, 3-hydroxypropyl group, A 3-chloro-2-hydroxypropyl group and the like can be mentioned. Further, esters of (meth) acrylic acid and polyfunctional alcohols such as ethylene glycol, triethylene glycol, polyethylene glycol, glycerin, trimethylolpropane, pentaerythritol and the like are also used. A typical amide is acrylamide. Further, as the allyl group-containing compound, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl isophthalate, diallyl maleate and the like are blended.

  Furthermore, an inorganic compound for imparting flame retardancy, an ultraviolet absorber for imparting weather resistance, and an antioxidant for preventing oxidative degradation are variously blended. That is, EVA which comprises a solar cell module is a resin composition which mix | blended various additives in order to satisfy | fill the function requested | required as a solar cell module.

  As an example of a method for integrating as a solar cell module, a vacuum laminating method can be given. This method is, for example, a solar cell in which a transparent protective member, a sealing resin on the transparent protective member side, and a wiring are provided on a dummy glass or a metal plate on a heating plate of a vacuum laminating apparatus heated to 100 to 150 ° C. The cell, the back sheet side sealing resin, and the back sheet are laminated in this order and allowed to stand. Thereafter, the vacuum laminating apparatus is closed and pressure reduction is started. After this pressure reduction state is maintained for 3 to 10 minutes, air is introduced from the air supply / exhaust pipe, and the rubber diaphragm is pressed against the laminated body by pressure difference to pressurize. . Although depending on the type of sealing resin, the heated vacuum laminating step is completed by holding this state for 10 to 40 minutes.

  The vacuum laminating method is only an example, and various laminating methods can be applied.

  As described above, when a laminated polyester resin film obtained by laminating the easy-adhesive composition of the present invention on a polyester resin film is used as a back sheet, compared with a conventional easy-adhesive composition, blocking resistance, EVA, etc. Adhesiveness to the sealing resin is greatly improved. Furthermore, the performance excellent in weather resistance, light resistance, and hydrolysis resistance can be exhibited.

Hereinafter, the present invention will be specifically described with reference to examples. In the examples, “parts” and “%” are based on weight unless otherwise specified.

The number average molecular weight of the hydroxyl group-containing resin (A) used in the present invention was determined under the following conditions using a gel permeation chromatograph (GPC): HLC-8220 manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Measurement conditions: Column temperature 40 ° C. Solvent tetrahydrofuran The glass transition temperature of the hydroxyl group-containing resin (A) used in the present invention was determined under the following conditions.

Measuring device: DSC220C manufactured by Seiko Electronics Corporation
Measuring method: DSC (Differential Scanning Calorimetry) method

Examples 1-4, Comparative Examples 1-3
As shown in Table 1 and Table 2 below, a two-component solution comprising a main component and a curing agent component using a hydroxyl group-containing resin (A), a polyisocyanate compound (B), a modified polyolefin (C), and an epoxy resin. Molds of the present invention and conventional easy adhesive compositions were prepared.

(Tack-free evaluation method)
The surface of the coating film that had just been applied and dried was evaluated for the stickiness of the coating film by finger touch.
Evaluation criteria ○: No stickiness ×: With stickiness

The easy-adhesive composition was applied to “E5001” (PET film manufactured by Toyobo Co., Ltd.) so that the coating amount after drying was 3 to 5 g / m ² , dried at 120 ° C. for 30 seconds, and easily adhered. After forming the layer, it was aged at 40 ° C. for 3 days. Moreover, the coated material was similarly created also when using "X10S" (Toray Industries, Inc. weather-resistant PET) instead of "E5001".

(Production method of adhesive evaluation sample with EVA)
Two sheets of the coated product provided with the easy-adhesion layer were cut into a width of 50 mm and a length of 100 mm, and one sheet of an EVA sheet (manufactured by Sanvic Co., Ltd.) cut into a width of 50 mm and a length of 100 mm was prepared. .

  Laminate so that the easy-adhesion layer is in contact with the EVA side, and then use a vacuum laminator to evacuate the resulting laminate at 150 ° C. for 5 minutes and hold it for 15 minutes to allow the crosslinking reaction to proceed. It was.

(Evaluation method for adhesion to EVA)
For adhesion to EVA, the sample for evaluation of easy adhesion is sandwiched between the upper and lower clips of a tensile tester (A & D Tensilon Tester Co., Ltd.) and the backsheet of the non-adhesive part is sandwiched between autographs. Was used to measure the peel strength at a crosshead speed of 200 mm / min with a width of 10 mm. Here, the unit of Table 1 and Table 2 is “N / 10 mm”.

  Furthermore, the sample for evaluation of easy adhesion was subjected to a pressure cooker test (PCT) for 24 hours (test conditions: 121 ° C., relative humidity was 100%), and the peel strength after the wet heat resistance test was evaluated under the same conditions as described above. . Similarly, the unit described in Table 1 and Table 2 is “N / 10 mm”.

(Evaluation method for blocking resistance)
Two back sheets are stacked in the direction in which the easy-adhesive layer faces do not face each other, that is, in the order of easy-adhesive layer / base material layer / easy-adhesive layer / base material layer, and a load of 5 kgf / cm ² is applied. Left for 24 hours. Then, it returned to room temperature and evaluated based on the following evaluation criteria in the state which removed the load.
○: There is no settling mark on the base material layer. △: There is a settling mark on the base material layer, but there is no setback setting.

  The outline of the materials in the table is shown below.

Base material: E5001 (PET manufactured by Toyobo Co., Ltd.) / X10S (weather-resistant PET manufactured by Toray Industries, Inc.), dry coating amount: 5 g / m 2
Elitel UE-3250; polyester resin manufactured by Unitika Ltd., hydroxyl value 5 solid content 100%
Acrydic 57-451; acrylic resin manufactured by DIC Corporation, hydroxyl value 11 (solid content) non-volatile content 55%
Unistor P-901; manufactured by Mitsui Chemicals, modified polyolefin, hydroxyl value 50, nonvolatile content 22%
HARDLEN P-5528; modified polyolefin manufactured by Toyobo Co., Ltd., hydroxyl value 3.3 Nonvolatile content 20%
Special Black 100; EVONIK DEGUSSA Co., Ltd. carbon black Solsperse 5000; Lubrizol Co., Ltd. phthalocyanine derivative JR-805; Teika Co., Ltd. rutile titanium oxide DISPERBYK-111; Having an acid value of 129 mg KOH / g
Denacol EX-321; manufactured by Nagase ChemteX Corporation, water-soluble polyfunctional glycidyl ether compound, epoxy equivalent 140, nonvolatile content 100%
Denacol EX-1310; manufactured by Nagase ChemteX Corporation, water-soluble polyfunctional glycidyl ether compound, epoxy equivalent 180, non-volatile content 100%
Epicron 860-80SE; manufactured by DIC Corporation, BPA type epoxy resin, epoxy equivalent 240, nonvolatile content 80%
Duranate N-3200; non-yellowing polyisocyanate manufactured by Asahi Kasei Co., Ltd., NCO% 23, nonvolatile content 100%
Duranate N-3300; manufactured by Asahi Kasei Co., Ltd. Non-yellowing polyisocyanate, NCO% 21.6 Nonvolatile content 100%

Claims (10)

  Resin (A) containing a hydroxyl group having a hydroxyl value of 1 to 200 mgKOH / g, a number average molecular weight of 5,000 to 50,000, and a glass transition temperature of 20 to 110 ° C., selected from an acrylic resin and a polyester resin, An easy-adhesive composition comprising a polyisocyanate compound (B), a modified polyolefin (C) introduced with a carboxyl group or a hydroxyl group.   The easy-adhesive composition of Claim 1 which contains 1-50 weight part of modified polyolefin (C) with respect to 100 weight part of resin (A) containing a hydroxyl group.   Furthermore, an epoxy compound is contained, The easily adhesive composition as described in any one of Claim 1 or 2 characterized by the above-mentioned.   Furthermore, the pigment (D) is contained, The easily adhesive composition as described in any one of Claims 1-3 characterized by the above-mentioned.   The easily adhesive composition according to claim 4, wherein the pigment is an inorganic oxide and / or carbon black.   The easy-adhesive composition according to claim 4 or 5, wherein 1 to 400 parts by weight of the pigment (D) is contained with respect to 100 parts by weight of the resin (A) containing a hydroxyl group. The laminated polyester resin film by which the cured film of the curable easily adhesive composition as described in any one of Claims 1-6 was laminated | stacked on the polyester resin film. A solar battery back sheet having a multilayer structure, comprising the laminated polyester resin film according to claim 7.   A solar cell comprising the solar cell backsheet according to claim 8 and a sealing material constituting a solar cell module. The solar cell according to claim 9, wherein the sealing material is a composition containing an ethylene-vinyl acetate copolymer as a main component.