JP2009248377A - Laminate sheet for solar cells, and solar cell module using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate sheet suitable to a sheet or a back sheet for sealing of solar cells wherein adhesiveness, durability, electrical insulation, productivity and the like are excellent, no specific cross-linking process is necessary and process steps of manufacturing modules can be simplified, and also to provide a solar cell module manufactured by the above manufacturing process. <P>SOLUTION: The laminate sheet usable in solar cells is manufactured by extruding an ethylene copolymer composition comprising 100 pts.wt. of an ethylene-polar monomer copolymer containing 1 wt.% or more of a carboxylic acid, a carboxylic acid salt, a carboxylic anhydride and a polar monomer containing a polar group selected from the group consisting of an epoxy group, a hydroxy group and an amino group and 0 to 3 pts.wt. of an alkoxy silane containing an amino group or an epoxy group an Al foil surface of a laminated body comprising a fluorine resin or a polyester resin on a surface of an Al foil to laminate thereon. A solar cell module manufactured by using the above sheet is also provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an element sealing sheet for fixing elements of a solar cell in a solar cell module and a laminate sheet suitable as a back sheet, and a solar cell module using the same. More specifically, the present invention relates to a solar cell element sealing sheet and a laminate sheet suitable as a back sheet using an ethylene copolymer composition, and a solar cell module using the same.

  Hydroelectric power generation, wind power generation, and solar power generation, which use inexhaustible natural energy to reduce carbon dioxide and improve other environmental problems, are in the spotlight. Among these, solar power generation has seen remarkable improvements in performance, such as power generation efficiency of solar cell modules, but the price has declined and the national and local governments have promoted the introduction of residential solar power generation systems. Its spread is remarkably advanced.

  Photovoltaic power generation converts solar energy directly into electrical energy using a silicon cell semiconductor (solar cell element), but the solar cell element used here has a reduced function when in direct contact with the outside air, The solar cell element is sandwiched between sealing materials to prevent foreign substances from entering and moisture from entering together with buffering. This sealing material is transparent and does not hinder power generation by light, does not melt or break down by heat (heat resistance), has good adhesion to the protective material glass or backsheet, Various performances, such as not causing remarkable deterioration and yellowing by sunlight, are required, and various compounding formulas are being studied to satisfy this. For example, as a typical formulation taking into account transparency, heat resistance, adhesiveness, flexibility, moldability, durability, etc., an ethylene / vinyl acetate copolymer blended with a peroxide and a silane coupling agent It is known to be used as a battery sealing material (for example, see Patent Document 1).

  Such a solar cell encapsulant is a two-step process in which a sheet of an ethylene / vinyl acetate copolymer blended with various additives and a solar cell element are encapsulated using the obtained sheet. It was necessary to adopt. In the production stage of this sheet, it is necessary to form at a low temperature so that the organic peroxide is not decomposed. Therefore, the extrusion speed cannot be increased, and in the sealing stage of the solar cell element, in the laminator It takes two steps, consisting of a process of temporary bonding for several minutes to ten and several minutes and a process of main bonding for several tens of minutes to one hour at a high temperature at which the organic peroxide decomposes in the oven. It was necessary to go through an adhesion process. Therefore, it takes time and labor to manufacture the solar cell module, which is one of the factors that increase the manufacturing cost.

  The present applicant does not require the use of such an organic peroxide, and therefore can significantly improve the production efficiency of the solar cell module, and also provides an alternative material having excellent characteristics as a solar cell sealing material. And an ethylene copolymer composition characterized by being an ethylene / unsaturated carboxylic acid copolymer or an ionomer thereof having an unsaturated carboxylic acid content of 4% by weight or more and a melting point of 85 ° C. or more, and The solar cell sealing sheet was proposed (Patent Document 2).

  In order to simplify the production process, the sealing material and backsheet are separately laid up and set on the glass or cell in the automation line, but this process is complicated. there were. As a result of the development of a sealing material and back sheet utilizing the insulating property while maintaining the excellent performance of the ethylene copolymer composition proposed by the applicant of the present invention, the present inventors Has reached

Japanese Examined Patent Publication No. 62-14111 JP 2000-186114 A

The present invention is excellent in adhesiveness, durability, electrical insulation, productivity, etc., and does not require a crosslinking step, and can simplify the process during module production, and a sheet for sealing an element for a solar cell and a backsheet The laminated body sheet | seat used for is provided.
The present invention also provides a solar cell module using the laminated sheet as an element sealing sheet and a back sheet.

The present invention provides a polar monomer having a polar group selected from the group consisting of a carboxylic acid, a carboxylate salt, a carboxylic acid anhydride, an epoxy group, a hydroxyl group, and an amino group on a laminate of a fluororesin or polyester resin and an Al foil. An ethylene copolymer composition in which 0 to 3 parts by weight of an alkoxysilane containing an amino group or an epoxy group is blended with 100 parts by weight of an ethylene / polar monomer copolymer containing 1% by weight or more is extruded and laminated on an Al foil surface. The laminated sheet used for the solar cell obtained by this is provided.
Moreover, this invention provides the laminated body sheet | seat of description used as a sheet | seat for element sealing of a solar cell, and a back sheet.

  The above-mentioned laminate sheet in which the ethylene copolymer is at least one selected from an ethylene / unsaturated carboxylic acid copolymer and an ethylene / unsaturated carboxylic acid ionomer is a preferred embodiment of the present invention.

  The above laminate sheet, wherein the alkoxysilane is a dialkoxysilane containing an amino group selected from 3-aminopropyl dialkoxysilane or N-3- (aminoethyl) -3-aminopropyl dialkoxysilane, This is a preferred embodiment of the present invention.

  Furthermore, the above-described laminate sheet in which the ethylene copolymer is further blended with a weathering stabilizer additive selected from an ultraviolet absorber, a light stabilizer and an antioxidant is a preferred embodiment of the present invention.

  The above-mentioned laminate sheet in which a laminate of the fluororesin or polyester resin and Al foil is laminated via a dry laminate adhesive is a preferred embodiment of the present invention.

  The above-described laminate sheet in which a laminate of a fluororesin or polyester resin and an Al foil is laminated via an anchor coating agent and an ethylene copolymer for sand is a preferred embodiment of the present invention.

  The sand ethylene copolymer is at least one selected from low density polyethylene, ethylene / unsaturated ester copolymer, ethylene / unsaturated carboxylic acid copolymer and ethylene / unsaturated carboxylic acid ionomer. A certain laminate sheet described above is a preferred embodiment of the present invention.

  The fluororesin is tetrafluoroethylene / ethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, chlorotrifluoroethylene / ethylene copolymer. The above-mentioned laminate sheet that is at least one selected from a polymer, polyvinyl fluoride, and polyvinylidene fluoride is a preferred embodiment of the present invention.

  The above laminated sheet, wherein the polyester resin is at least one selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polycyclohexanedimethanol-terephthalate (PCT). This is a preferred embodiment of the invention.

  Furthermore, this invention provides the solar cell module which used the said laminated body sheet as the element sealing sheet | seat and back sheet | seat of a solar cell.

ADVANTAGE OF THE INVENTION According to this invention, the laminated body sheet | seat used as an element sealing sheet | seat and back sheet | seat of a solar cell excellent in adhesiveness, durability, electrical insulation, productivity, etc. is provided.
Moreover, according to this invention, the solar cell module using the laminated body sheet | seat which has the outstanding performance as a sheet | seat for solar cell element sealing and a back sheet is provided.

  The ethylene copolymer composition provided by the present invention contains 1% by weight or more of a polar monomer having a polar group selected from the group consisting of carboxylic acid, carboxylate, carboxylic anhydride, epoxy group, hydroxyl group and amino group It is an ethylene copolymer composition in which 0 to 3 parts by weight of dialkoxysilane containing an amino group or an epoxy group is blended with 100 parts by weight of the ethylene / polar monomer copolymer.

  As the polar monomer of the present invention, an unsaturated carboxylic acid, a salt thereof or an anhydride thereof is preferable. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, and maleic anhydride monoester, and acrylic acid or methacrylic acid is particularly preferable. Ethylene / acrylic acid copolymers and ethylene / methacrylic acid copolymers are examples of particularly preferred ethylene / polar monomer copolymers.

  A preferred example of the ethylene / unsaturated carboxylate in the present invention is an ionomer of an ethylene / unsaturated carboxylic acid copolymer. Examples of the ionomer of the ethylene / unsaturated carboxylic acid copolymer include alkali metals such as lithium and sodium, and polyvalent metals such as calcium, magnesium, zinc and aluminum. The advantage of using such an ionomer is transparency and high storage elastic modulus at high temperature, and it is desirable to use a neutralization degree of, for example, about 80% or less. Then, it is not a good idea to use a material having a very high degree of neutralization. For example, it is preferable to use a material having a degree of neutralization of 60% or less, particularly 30% or less.

  In the present invention, when an ethylene / unsaturated carboxylic acid copolymer or its ionomer is used as the ethylene / polar monomer copolymer, the unsaturated carboxylic acid content is 1 from the viewpoint of transparency and adhesiveness of the resulting copolymer. It is preferable that it is weight% or more. Below this, the adhesiveness is insufficient. Further, when the unsaturated carboxylic acid content is increased, more excellent transparency can be obtained, but problems such as a lower melting point and increased hygroscopicity occur, so the unsaturated carboxylic acid content is 20%. It is desirable that the content is not more than wt%, preferably not more than 15 wt%.

  The melting point of the ethylene / polar monomer copolymer of the present invention is 55 ° C. or higher, preferably 60 ° C. or higher, particularly preferably 70 ° C. or higher. In the present invention, if the melting point of the copolymer or ionomer is too low, the heat resistance is not sufficient, and when used as a solar cell element sealing material, it is deformed due to a temperature rise during use of the solar cell, or the solar cell. When a module is manufactured by a thermocompression bonding method, these sealing materials may flow out more than necessary to cause burrs.

  The ethylene / epoxy group-containing monomer copolymer is preferably a random copolymer of ethylene and an epoxy group-containing monomer, and is optionally random copolymerized with another comonomer, preferably the unsaturated ester. . Typical examples of epoxy group-containing monomers include glycidyl (meth) acrylates such as glycidyl acrylate and glycidyl methacrylate, and copolymers include ethylene / methyl acrylate / glycidyl methacrylate copolymers and ethylene / acrylic. Examples include ethyl acetate / glycidyl methacrylate copolymer, ethylene / butyl acrylate / glycidyl methacrylate copolymer, and ethylene / glycidyl methacrylate copolymer.

  A typical example of the unsaturated alcohol component of the ethylene / unsaturated alcohol copolymer is vinyl alcohol. More specifically, a partially or completely saponified ethylene / vinyl acetate copolymer can be mentioned. Examples of the ethylene / unsaturated amine copolymer include an ethylene / vinylamine copolymer.

  As the ethylene copolymer of the present invention, in consideration of molding processability, mechanical strength and the like, JIS K7210-1999, 190 ° C., melt flow rate at 2160 g load (MFR, hereinafter the same) is 1 to 100 g / 10 min. In particular, it is preferable to use the one of 5 to 50 g / 10 minutes.

  The ethylene copolymer of the present invention may contain monomers other than the polar monomer of the present invention. For example, when a copolymer of vinyl ester or (meth) acrylic acid ester is used, flexibility is imparted. An effect is obtained. It is necessary to use the content within a range that does not impair the object of the present invention.

  The ethylene / polar monomer copolymer of the present invention can be obtained by radical copolymerization under high temperature and high pressure. An ionomer of an ethylene / unsaturated carboxylic acid copolymer can be obtained by reacting an ethylene / unsaturated carboxylic acid copolymer with a metal compound.

  In the present invention, as an alkoxysilane containing an amino group or an epoxy group that is blended in the ethylene copolymer composition as necessary, N-2 (aminoethyl) 3-aminopropylmethyltrimethoxysilane, N-2 ( Aminoethyl) 3-aminopropylmethyltriethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, 3-aminopropylmethyltrimethoxysilane, 3-aminopropylmethyltriethoxysilane, N-phenyl-3 -Aminopropylmethyltrimethoxysilane, N-phenyl-3-aminopropylmethyltriethoxysilane, 3-methyltrimethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, 3-methyltrimethoxysilyl -N- (1,3-dimethyl-butylidene) propylamine, 2 -(3,4 epoxy cyclohexyl) ethylmethyltrimethoxysilane, 2- (3,4 epoxycyclohexyl) ethylmethyltriethoxysilane, 3-glycidoxypropylmethyltrimethoxysilane, 3-glycidoxypropylmethyltriethoxysilane And so on.

  Further, as dialkoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldiethoxysilane, N-2 (aminoethyl) 3-aminopropyldimethoxysilane 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropylmethyldiethoxysilane, 3-methyldimethoxysilyl -N- (1,3-dimethyl-butylidene) propylamine, 3-methyldimethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, 2- (3,4-epoxycyclohexyl) ethylmethyldimethoxysilane, 2 -(3,4 Epoxycyclohexyl) ethylmethyl Diethoxy silane, 3-glycidoxypropyl methyl dimethoxy silane, and 3-glycidoxypropyl methyl diethoxy silane can be cited. Among these, 3-aminopropyl dialkoxysilane or N-3- (aminoethyl) -3-aminopropyl dialkoxysilane is particularly preferable.

  When trialkoxysilane is used in the ethylene copolymer composition, the adhesiveness starts to decrease relatively quickly, but when the dialkoxysilane of the present invention is used, the processing stability during sheet molding is more maintained. can do.

  The alkoxysilane having an amino group or an epoxy group is blended at a ratio of 0 to 3 parts by weight with respect to 100 parts by weight of the ethylene / polar monomer copolymer. From the viewpoint, it is blended in an amount of 3 parts by weight or less, preferably 0.03 to 3 parts by weight, particularly 0.05 to 1.5 parts by weight, based on 100 parts by weight of the ethylene / polar monomer copolymer.

  In addition, weather resistance stabilizers such as antioxidants, light stabilizers and ultraviolet absorbers can be optionally added to the ethylene copolymer composition, but in order to prevent deterioration of the sealing material based on ultraviolet rays in sunlight. It is effective to add at least one weathering stabilizer such as an antioxidant, a light stabilizer, and an ultraviolet absorber. As the antioxidant, for example, various hindered phenols and phosphites can be preferably used. Moreover, as a light stabilizer, a hindered amine type thing can be used conveniently. Examples of the ultraviolet absorber include 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2-carboxybenzophenone, and 2-hydroxy. Benzophenones such as -4-n-octoxybenzophenone, 2- (2′-hydroxy-3 ′, 5′-ditert-butylphenyl) benzotriazole, 2- (2′-hydroxy-5-methylphenyl) benzo Benzotriazoles such as triazole, 2- (2′-hydroxy-5-third octylphenyl) benzotriazole, salicylic acid esters such as phenyl salicylate, p-octylphenyl salicylate, etc. are used. it can. It is effective to add these weather stabilizers in an amount of 5 parts by weight or less, particularly 0.1 to 3 parts by weight, based on 100 parts by weight of the ethylene copolymer.

  The ethylene copolymer composition of the present invention may contain any other additive as long as the purpose of use is not impaired. As such other additives, various known additives can be used. Examples of other additives include pigments, dyes, lubricants, antiblocking agents, foaming agents, foaming aids, crosslinking agents, crosslinking aids, inorganic fillers, flame retardants and the like.

  In the ethylene copolymer composition of the present invention, for example, a fatty acid salt of a metal such as cadmium or barium can be optionally blended as a discoloration preventing agent. Further, since the sealing material on the lower protective material side does not require transparency, pigments, dyes, inorganic fillers, and the like can be blended as necessary for the purpose of coloring and improving power generation efficiency. Examples thereof include white pigments such as titanium oxide and calcium carbonate, blue pigments such as ultramarine, black pigments such as carbon black, and glass beads and light diffusing agents. In particular, when the present invention is applied to a system in which an inorganic pigment such as titanium oxide is blended, the effect of preventing a decrease in insulation resistance is excellent, which is preferable. A suitable blending amount of the inorganic pigment is 100 parts by weight or less, preferably 0.5 to 50 parts by weight, particularly preferably 4 to 50 parts by weight with respect to 100 parts by weight of the ethylene / polar monomer copolymer.

  Examples of the dry laminate adhesive that bonds the fluororesin or polyester resin and the Al foil include a two-component reaction type polyurethane resin adhesive, and a solvent type or a solventless type can be selected.

  The two-component reaction type polyurethane resin adhesive is desirably an adhesive having excellent hydrolysis resistance. As a desirable form, a composition in which a crosslinking agent is blended with either a simple substance or a mixture of polyester polyol or polyester urethane polyol subjected to chain extension with a bifunctional or higher functional isocyanate compound is desirable. Alternatively, an adhesive composition in which 1 to 50 parts by weight of a compound selected from at least one kind selected from a carbodiimide compound, an oxazoline compound, and an epoxy compound is blended with 100 parts by weight of the above composition is desirable.

  Polyester polyols used in the present invention include aliphatic systems such as succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid and brassic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc. One or more aromatic dibasic acids, and aliphatics such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, dodecanediol It can be obtained by using one or more of alicyclic diols such as cyclohexanediol and hydrogenated xylylene glycol, and aromatic diols such as xylylene glycol. Further, the hydroxyl groups at both ends of this polyester polyol are, for example, 2,4- or 2,6-tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, methylene diisocyanate, isopropylene diisocyanate, lysine diisocyanate, 2 , 2,4-- or 2,4,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isopropylidene dicyclohexyl-4,4 ' -Isocyanate compound selected from diisocyanates, etc., or the above isocyanate compound selected from at least one or more Adducts made, biuret body, such as a polyester urethane polyol chain extension with isocyanurate products thereof.

  As the polyol component considered as a polyurethane-based material, polyether polyol, polycarbonate polyol, acrylic polyol, and the like can be considered, and those containing these components as the main component can be used. And acrylic polyol are preferred.

  The above-mentioned isocyanate compounds can be used as a crosslinking agent for crosslinking these, and the type is not limited to these, and any type of crosslinking agent can be used as long as it is reactive with active hydrogen groups.

  N, N′-di-o-toluylcarbodiimide, N, N′-diphenyl is used as a carbodiimide compound to block the carboxyl group generated when hydrolysis occurs in an accelerated environment under high temperature and high humidity. Carbodiimide, N, N′-di-2,6-dimethylphenylcarbodiimide, N, N′-bis (2,6-diisopropylphenyl) carbodiimide, N, N′-dioctyldecylcarbodiimide, N-triyl-N′-cyclohexyl Carbodiimide, N, N′-di-2,2-di-tert. -Butylphenylcarbodiimide, N-triyl-N'-phenylcarbodiimide, N, N'-di-p-nitrophenylcarbodiimide, N, N'-di-p-aminophenylcarbodiimide, N, N'-di-p- Examples include hydroxyphenyl carbodiimide, N, N′-di-cyclohexylcarbodiimide, and N, N′-di-p-toluylcarbodiimide.

  Examples of the oxazoline compound having the same action include 2-oxazoline, 2-methyl-2-oxazoline, 2-phenyl-2-oxazoline, 2,5-dimethyl-2-oxazoline, and 2,4-diphenyl-2-oxazoline. Monooxazoline compounds such as 2,2 ′-(1,3-phenylene) -bis (2-oxazoline), 2,2 ′-(1,2-ethylene) -bis (2-oxazoline), 2,2 ′ Examples thereof include dioxazoline compounds such as-(1,4-butylene) -bis (2-oxazoline) and 2,2 '-(1,4-phenylene) -bis (2-oxazoline).

  Similarly, epoxy compounds include diglycidyl ethers of aliphatic diols such as 1,6-hexanediol, neopentyl glycol, polyalkylene glycol, sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, trimethylol. Polyglycidyl ether of aliphatic polyol such as propane, polyglycidyl ether of alicyclic polyol such as cyclohexanedimethanol, aliphatic, aromatic such as terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, trimellitic acid, adipic acid, sebacic acid Diglycidyl ester or polyglycidyl ester, resorcinol, bis- (p-hydroxyphenyl) methane, 2,2-bis- (p-hydroxyphenyl) Dipanidyl or polyglycidyl ether of polyphenol such as lopan, tris- (p-hydroxyphenyl) methane, 1,1,2,2-tetrakis (p-hydroxyphenyl) ethane, N, N-diglycidylaniline, N-glycidyl derivatives of amines such as N, N-diglycidyl toluidine, N, N, N ′, N′-tetraglycidyl-bis- (p-aminophenyl) methane, triglycidyl derivatives of aminofail, triglycidyl tris (2-Hydroxyethyl) isocyanurate, triglycidyl isocyanurate, orthocresol type epoxy, phenol novolac type epoxy.

  When fluororesin or polyester resin and Al foil are laminated via an anchor coat agent and an ethylene copolymer for sand, the anchor coat agent may basically have a different solid content, but dry laminate adhesion Although the same thing as an agent can be used, a polyethyleneimine adhesive and an organic titanium adhesive can also be used in addition to a two-component urethane adhesive.

  The ethylene copolymer for sand is selected from low density polyethylene, ethylene / unsaturated ester copolymer, ethylene / unsaturated carboxylic acid copolymer and ethylene / unsaturated carboxylic acid ionomer. The low-density polyethylene can be selected from those obtained by a high-pressure process and a copolymer of ethylene and an unsaturated hydrocarbon having 6 to 10 carbon atoms by a Ziegler-Natta catalyst or a metallocene catalyst.

  Examples of the fluororesin of the present invention include tetrafluoroethylene / ethylene copolymer (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), poly Examples thereof include fluorine-based substrates selected from chlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene / ethylene copolymer (PCTFEE), polyvinyl fluoride (PVF), and polyvinylidene fluoride (PVDF).

  Examples of the polyester resin of the present invention include polyester base materials in which the polyester resin is selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polycyclohexanedimethanol-terephthalate (PCT). .

When a polyester base material is used, it is obtained by using a polybasic acid or an ester-forming derivative thereof and a polyol or an ester-forming derivative thereof. As the polybasic acid component, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride 2 or more acid components such as 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid, dimer acid, maleic acid, itaconic acid, and As the polyol component, ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, trimethylolpropane, pentaerythritol, xylene glycol, dimethylolpropane, poly (Echile Oxide) glycol, poly (tetramethylene oxide) glycol, and polyester obtained by using one or more polyol components containing carboxylic acid groups, sulfonic acid groups, amino groups, or salts thereof. However, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polycyclohexanedimethanol-terephthalate (PCT) are generally used.

  However, polyester base materials, particularly polyethylene terephthalate, are materials that are concerned about hydrolysis. Therefore, when a polyester base material such as polyethylene terephthalate is used, hydrolysis resistance with a number average molecular weight in the range of 18000 to 40000, a cyclic oligomer content of 1.5 wt% or less, and an intrinsic viscosity of 0.5 dl / g or more. It is preferable that it is the polyester base material which has this. Like the polyol A described above, when the molecular terminal is a carboxylic acid group, such a polyester base material acts as heat, water, and further as an acid catalyst and is most affected by hydrolysis. A solid phase polymerization method that can increase the number average molecular weight without increasing the amount may be used, or the terminal carboxylic acid group may be sealed with a carbodiimide compound, an epoxy compound, or an oxazoline compound. In addition, when there is a concern about the effect of shrinkage due to heat when manufacturing a solar cell module, a polyester base material having a heat shrinkage rate of 1% or less, preferably 0.5% or less by performing an annealing treatment is used. It is possible to use.

When weather resistance is required, UV absorbers such as benzophenone, benzotriazole, and triazine, hindered phenol-based, phosphorus-based, sulfur-based, tocopherol-based antioxidants, and hindered amine-based light stabilizers are also appropriately used. It is possible to mix.
Moreover, it is not limited to a fluororesin and a polyester resin, and it is appropriately selected in consideration of heat resistance, strength properties, electrical insulation, etc., such as a polycarbonate resin, an acrylic resin, a polyolefin resin, a polyamide resin, and a polyarylate resin. A substrate can be used.

  Although the polyester base material used for the solar cell backside sealing sheet may be transparent, it is preferable to use a white polyester film from the viewpoint of improving the power generation efficiency of the solar cell element. In particular, when the solar cell back surface sealing sheet has a multilayer structure, it is also possible to provide a white polyester film on at least the base material bonded to the filler. The white polyester film used at this time is a “pigment dispersion type” in which white additives such as titanium oxide, silica, alumina, calcium carbonate, and barium sulfate are added, or polymers and fine particles that are incompatible with polyester are added, and biaxial It is possible to use a “fine foam type” or the like that is whitened by forming voids at the blend interface during stretching. In the “fine foaming type”, the polymer incompatible with the polyester is preferably a polyolefin resin such as polyethylene, polypropylene, polybutene, polymethylpentene. If necessary, polyalkylene glycol or a copolymer thereof can be used as a compatibilizing agent. Specific examples of the fine particles include organic particles and inorganic particles. Silicon particles, polyimide particles, crosslinked styrene-divinylbenzene copolymer particles, crosslinked polyester particles, fluorine-based particles, and the like are used. As the inorganic particles, calcium carbonate, silicon dioxide, barium sulfate or the like is used.

  Lamination of the ethylene copolymer composition of the present invention to the Al foil surface can be carried out by a known method using an extrusion laminator or a horizontal T-die extruder. When extrusion lamination is performed on the Al foil surface, it is possible to perform a corona treatment in advance. Further, the molten film can be subjected to ozone treatment and laminated to produce a solar cell element sealing sheet and back sheet. For example, an ethylene / polar monomer copolymer and a silane coupling agent, an inorganic pigment added if necessary, and other additives are dry-blended in advance and supplied from the hopper of the extruder. It can also be added in batches. It can be obtained by extruding into a sheet form at 110 to 300 ° C. and laminating on the Al foil surface. The thickness of the sealing sheet layer is not particularly specified, but is usually about 0.2 to 2 mm.

The laminate sheet used as the solar cell element sealing sheet and the back sheet of the present invention has a function as a sealing sheet for the solar cell module and a function as a back sheet. It can be used suitably.
A solar cell module can be manufactured by fixing a solar cell element with a protective material from above and below using such a sealing sheet and back sheet and a sealing sheet having the above composition. Examples of such solar cell modules include various types. For example, the thing of the structure pinched | interposed with a sealing material from the both sides of a solar cell element like the upper transparent protective material / sheet | seat for sealing materials / solar cell element / sheet | seat and back sheet | seat for sealing materials can be mentioned. In the solar cell module having such a configuration, the sealing material of the present invention containing no inorganic pigment is used as the sealing material for the upper transparent protective material. Sometimes used.

  Another type of solar cell module has a structure in which a sheet for encapsulant and an upper transparent protective material are formed on a solar cell element formed on the inner peripheral surface of the lower substrate protective material, upper transparent protection There is a configuration in which a sealing material sheet and a lower transparent protective material are formed on a solar cell element formed on the inner peripheral surface of the material, for example, an amorphous solar cell element was created on a glass by sputtering or the like The thing of the structure etc. which form the sheet | seat for sealing and back sheet | seat on a thing can be mentioned.

  Solar cell elements include single-crystal silicon, polycrystalline silicon, amorphous silicon, and other silicon systems, and gallium-arsenic, copper-indium-selenium, cadmium-tellurium and other III-V and II-VI compound semiconductor systems. Various solar cell elements can be used. The sealing material of the present invention is particularly useful for sealing an amorphous solar cell element such as amorphous silicon.

  Examples of the upper protective material constituting the solar cell module include glass, acrylic resin, polycarbonate, polyester, and fluorine-containing resin. The sealing material of this invention shows favorable adhesiveness with respect to these upper protection materials.

  The solar cell module may be manufactured by adhering the encapsulant sheet to the solar cell element or the protective material at a temperature at which the encapsulant sheet of the present invention is melted and taking a necessary time.

  Although the ethylene copolymer composition of the present invention is suitably used as a solar cell encapsulant, it can also be used for other applications utilizing its characteristics. Examples of such other uses include use as an interlayer film of laminated glass.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited by these examples.
The raw materials and physical property evaluation methods used in Examples and Comparative Examples are shown below.

1. Raw material (1) Resin (1): Ethylene / methacrylic acid copolymer (methacrylic acid content: 15% by weight, MFR: 25 g / 10 min)
(2) Resin (2): Zn ionomer of ethylene / methacrylic acid copolymer (methacrylic acid content: 15% by weight, MFR: 5.5 g / 10 min)
(3) Resin (3): High-pressure method low-density polyethylene (density: 0.917 g / cm ³ , MFR: 7.2 g / 10 min)
(4) Silane coupling agent (1): N-2 (aminoethyl) 3-aminopropyltriethoxysilane (5) Silane coupling agent (2): N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane (6) Antioxidant: Irganox 1010 (Ciba Specialty Chemicals)
(7) UV absorber: 2-hydroxy-4-n-octoxybenzophenone (8) Light-resistant stabilizer: Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (9) Anchor coating agent: Nippon Soda made urethane resin
(Main agent) Titabond T185 / (Curing agent) T185 curing agent / Methanol = 10 / 0.2 / 90

2. Base material (1) Blue glass: thickness 3 mm, size 7.5 cm × 12 cm
(2) Base material: PET (12 μm) / urethane adhesive / resin (3) (15 μm) / Al foil (7 μm)
A PET base material coated with an anchor coating agent and an Al foil base material were prepared by sand lamination at a resin temperature of 320 ° C.

3. Base material adhesion condition: Bonding at 150 ° C. × 10 minutes Bonding device: LM-50 × 50S made by NPC
Sample configuration: Glass / sealing sheet and back sheet Measurement conditions: Cut into a width of 10 mm, and the adhesive strength between the back sheet / sheet and between the glass / sheet was measured at a tensile speed of 50 mm / min.

4). Durability A bonded sample was prepared under the following conditions, and the initial YI was measured with a color computer (manufactured by Suga Test Instruments).
Condition: Bonding at 150 ° C. × 10 minutes Bonding device: NPC LM-50 × 50S
Sample configuration: Glass / sheet / back sheet Next, the following aging was performed, YI was measured, and the yellowing degree was evaluated.
Heat resistance: 85 ° C. × 500, 1000 hours Humidity resistance: 85 ° C. × 90% RH × 1000 hours Weather resistance: 83 ° C. × 180 W / m ² × 50% RH × 2000 hours (Atlas Ci-4000) Implementation)

Example 1
5000 g of the resin (1), 25 g of the silane coupling agent (1), 1 g of the antioxidant, 10 g of the ultraviolet absorber, 3.5 g of the light resistant stabilizer, and 100 g of white pigment (concentration 60% by weight) were weighed and mixed. The obtained impregnated pellets are kneaded using an extruder (L / D = 26, full flight screw, compression ratio 2.6) at a processing temperature of 120 ° C. so that the thickness of the sheet layer becomes 0.4 mm. Then, a molten resin was bonded to the Al foil surface of a PET / Al base material prepared in advance to obtain a laminate sheet that could be used as a solar cell sealing sheet and back sheet. Using this laminate, the adhesive strength with the glass substrate was measured. The results are shown in Table 1.

(Example 2)
In Example 1, a laminate sheet was obtained in the same manner as in Example 1 except that the resin (2) was changed to 5000 g and the silane coupling agent (2) was changed to 10 g and kneaded at a processing temperature of 180 ° C. It was. The adhesive strength with a glass substrate was measured using this laminate. The results are shown in Table 1.

The laminate sheet provided by the present invention is a laminate sheet that is excellent in adhesion, durability, electrical insulation, productivity, and the like, and is suitable as a solar cell element sealing sheet and a back sheet.
According to the present invention, it is a laminate sheet that does not require a crosslinking step, and since the solar cell element sealing sheet and the back sheet are integrated, the module production process is simplified because the number of layup steps is reduced. Provided is a laminate sheet that can be modified.
According to the present invention, a solar cell module using a laminate sheet having excellent performance as a solar cell element sealing sheet and a back sheet is provided.

Claims (11)

  1% by weight of a polar monomer having a polar group selected from the group consisting of carboxylic acid, carboxylate salt, carboxylic anhydride, epoxy group, hydroxyl group and amino group in a laminate of a fluororesin or polyester resin and an Al foil An ethylene copolymer composition in which 0 to 3 parts by weight of an alkoxysilane containing an amino group or an epoxy group is blended with 100 parts by weight of the ethylene / polar monomer copolymer contained above is extruded and laminated on the Al foil surface. The laminated sheet used for the solar cell obtained. The laminate sheet according to claim 1, which is used as an element sealing sheet and a back sheet of a solar cell.   The laminate sheet according to claim 1, wherein the ethylene / polar monomer copolymer is at least one selected from an ethylene / unsaturated carboxylic acid copolymer and an ionomer of an ethylene / unsaturated carboxylic acid copolymer.   The alkoxysilane of claim 1 to 3, wherein the alkoxysilane is a dialkoxysilane containing an amino group selected from 3-aminopropyl dialkoxysilane or N-3- (aminoethyl) -3-aminopropyl dialkoxysilane. The laminated body sheet in any one.   The laminate sheet according to any one of claims 1 to 4, wherein a weathering stabilizer additive selected from an ultraviolet absorber, a light stabilizer and an antioxidant is further blended with the ethylene / polar monomer copolymer.   The laminate sheet according to any one of claims 1 to 5, wherein a laminate of the fluororesin or polyester resin and an Al foil is laminated via a two-component reaction type polyurethane resin adhesive layer.   The fluororesin is tetrafluoroethylene / ethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, chlorotrifluoroethylene / ethylene copolymer. The laminate sheet according to any one of claims 1 to 6, wherein the laminate sheet is at least one selected from a polymer, polyvinyl fluoride, and polyvinylidene fluoride.   The polyester resin is at least one selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polycyclohexanedimethanol-terephthalate (PCT). The laminate sheet according to 1.   The laminate sheet according to any one of claims 1 to 8, wherein the laminate sheet is prepared by laminating the Al foil surface by corona treatment when the ethylene copolymer composition is extrusion laminated to the Al foil surface.   The laminate sheet according to any one of claims 1 to 9, wherein, when the ethylene copolymer composition is extrusion laminated on the Al foil surface, the molten film of the ethylene copolymer composition is subjected to ozone treatment and laminated. The solar cell module which used the laminated body sheet | seat described in any one of Claims 1-10 as a sheet | seat for element sealing of a solar cell, and a back sheet.