JP2015005594A - Seal-material composition for solar battery, seal-material layer for solar battery, and solar battery module arranged by use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a composition for a solar battery which enables the formation of a seal-material layer for a solar battery which is sufficiently crosslink-curable at the time of laminating a module, and arranged so that its degradation can be suppressed even when being exposed to ultraviolet light over a long period of time; a seal-material layer for a solar battery which is sufficiently crosslink-curable at the time of laminating a module, and arranged so that its degradation can be suppressed even when being exposed to ultraviolet light over a long period of time; and a solar battery module arranged by use of such a seal-material layer.SOLUTION: A seal-material composition for a solar battery comprises: a dibutyl hydroxy toluene (BHT) derivative; and a hindered-amine-based compound having a phenol skeleton in a molecule thereof.

Description

  The present invention relates to a sealing material layer composition for solar cells, a sealing material layer for solar cells, and a solar cell module using the same.

  The use of solar energy provides a promising alternative energy source for conventional fossil fuels, and therefore the development of devices that can convert solar energy into electricity, eg, photovoltaic devices (which also serve as solar cells In recent years, much attention has been paid to the development of such products. Several different types of mature photovoltaic devices have been developed, including silicon-based devices, III-V and II-VI PN junction devices, copper-indium-gallium, to name a few. -Selenium (CIGS) thin film devices, organic sensitizer devices, organic thin film devices, and cadmium sulfide / cadmium telluride (CdS / CdTe) thin film devices. More details regarding these devices can be found in the literature (see, for example, Non-Patent Document 1). However, there is still room for improvement in the durability and light stability of these devices including encapsulants, and it is an ongoing challenge for many researchers to develop technology to improve this efficiency. It is.

  In a sealing material layer for existing solar cell applications, various additives are included in order to prevent oxidative degradation, light degradation, and the like of the resin. For example, a method is used in which an antioxidant or a light stabilizer is added to prevent discoloration such as white turbidity or yellowing caused by deterioration of a resin or additive due to long-term use (for example, see Patent Document 1). .

  Moreover, normally, the sealing material layer for solar cells also has a role of maintaining the shape of the solar cell module made of members such as cells, glass, and a back sheet, and has sufficient crosslinkability. Is also sought. However, the addition of a large amount of an antioxidant or a light stabilizer in the above method significantly reduces the crosslinkability of the matrix resin of the encapsulant layer, resulting in a problem that the characteristics as the encapsulant layer are lost. is there. On the other hand, when the addition amount of organic peroxide or the like is increased in order to maintain the crosslinkability, the organic peroxide remaining in the encapsulant layer after the crosslinking reaction and the decomposition product thereof may cause deterioration of different matrix resins. turn into.

  Further, it has been found that phenolic antioxidants often used as antioxidants are discolored in the antioxidant mechanism, and can cause yellowing when added in a large amount to the encapsulant layer.

JP 2003-243682 A Lin et al., “High Photoelectric Conversion Efficiency of Metal Phthalocyanine / Fullerene Heterojunction Photovoltaic Device, 12th International Journal, 11th.

  In light of such circumstances, the present invention is for a solar cell capable of forming a solar cell encapsulant layer that can be sufficiently crosslinked and cured at the time of module lamination, and that is prevented from being deteriorated even when exposed to ultraviolet rays for a long time. An object is to provide a composition.

  The present invention also provides a solar cell encapsulant layer that can be sufficiently crosslinked and cured at the time of module lamination, and that is prevented from being deteriorated even when exposed to ultraviolet rays for a long time, and a solar cell module using the same. The purpose is to do.

  As a result of intensive studies to solve the above problems, the present inventors have achieved the above object by using the following solar cell encapsulant composition, solar cell encapsulant layer, and solar cell module using the same. The inventors have found that this can be achieved and have completed the present invention.

  The sealing material composition for solar cells of the present invention is characterized by comprising a dibutylhydroxytoluene (BHT) derivative and a hindered amine compound having a phenol skeleton in the molecule.

  By using the solar cell encapsulant composition of the present invention, a solar cell encapsulant layer that can be sufficiently crosslinked and cured at the time of module lamination and that has been prevented from being deteriorated even when exposed to ultraviolet rays for a long time is easily obtained. Can be formed. The expression of the above-described effects is presumed to be due to the mechanism described below, but it is not specified that the following mechanism is essential. First, since the dibutylhydroxytoluene (BHT) derivative has a low molecular weight, it is presumed that it easily diffuses in the matrix resin and effectively suppresses oxidative degradation in the encapsulant layer, but has a low molecular weight. Therefore, there is a concern that it will bleed out. On the other hand, it is estimated that the hindered amine compound has a higher molecular weight, reduces the possibility of bleeding out, and is easy to maintain long-term functional expression. By including the dibutylhydroxytoluene (BHT) derivative and the hindered amine compound, the solar cell encapsulant composition of the present invention can prevent oxidative degradation over a long period of time without inhibiting crosslinking, and suppresses photodegradation. It becomes possible.

  In the present invention, dibutylhydroxytoluene (BHT) means 2,6-di-tert-butyl-4-methylphenol. The dibutylhydroxytoluene (BHT) derivative means a compound obtained by chemically modifying the dibutylhydroxytoluene.

  In addition, the hindered amine in the present invention generally directly captures radicals generated in the system by light irradiation and the like, and radicals are chain-reacted by stabilization of radical species by their own steric hindrance structure or conjugated (resonance) structure. It means an amine compound having the property of stopping (suppressing) the process of being carried out.

  Moreover, in the solar cell sealing material composition of the present invention, it is preferable that the hindered amine compound has a dibutylhydroxytoluene skeleton. By using the hindered amine compound, the hindered amine compound itself can be further provided with a function as an antioxidant. As a result, the solar cell encapsulant layer formed of the composition can more effectively exhibit an oxidation deterioration preventing effect and a light deterioration suppressing effect over a long period of time.

  Moreover, the solar cell sealing material composition of this invention WHEREIN: It is preferable that the said hindered amine type compound has a 2,2,6,6-tetramethyl-4-piperidyl structure. By including the said structure, the sealing material layer for solar cells formed with the said composition becomes easy to express the oxidation deterioration prevention effect and the light deterioration suppression effect more reliably over a long period of time.

  Moreover, in the solar cell sealing material composition of this invention, it is preferable that the molecular weights of the said hindered amine type compound are 400-4000. By using the hindered amine compound, the hindered amine compound itself can be more effectively suppressed from bleeding out. As a result, the solar cell encapsulant layer formed from the composition can more reliably exhibit an oxidation deterioration preventing effect and a light deterioration suppressing effect over a long period of time.

  Moreover, in the sealing material composition for solar cells of this invention, it is preferable that the hindered amine type compound which does not have a phenol skeleton in a molecule | numerator is further included. When the hindered amine compound is further used in combination, the solar cell encapsulant layer formed of the composition may easily exhibit the above-described oxidation deterioration preventing effect and light deterioration suppressing effect over a long period of time.

  Further, in the solar cell encapsulant composition of the present invention, the matrix resin of the solar cell encapsulant composition contains an ethylene copolymer as a main component, and the dibutylhydroxy is added to 100 parts by weight of the matrix resin. It is preferable that 0.001 to 0.2 part by weight of the toluene derivative and 0.001 to 0.3 part by weight of the hindered amine compound are included. By setting it as the said compounding quantity, the bridge | crosslinking inhibition of matrix resin can be suppressed more effectively. As a result, the solar cell encapsulant layer formed of the composition can exhibit the effect of preventing oxidative degradation and suppressing light degradation over a long period of time without more reliably inhibiting crosslinking.

  In addition, the said main component shall mean the case where the said matrix resin is a mixture of several resin, and contains 50 weight% or more by weight ratio. The weight ratio is more preferably 70% by weight or more, and still more preferably 90% by weight.

  Moreover, it is preferable that the sealing material composition for solar cells of this invention contains an ultraviolet-absorbing compound further. By using the ultraviolet absorbing compound, it is possible to further suppress ultraviolet deterioration, impart a wavelength conversion function, and the like, and to make the solar cell sealing material layer formed of the composition more multifunctional.

  Moreover, in the solar cell encapsulant composition of the present invention, the matrix resin preferably contains an ethylene-vinyl acetate copolymer as a main component. By using an ethylene-vinyl acetate copolymer as a main component as the matrix resin, a solar cell encapsulant layer having more excellent light transmittance and durability can be obtained.

  On the other hand, the solar cell encapsulant layer of the present invention is formed using the above solar cell encapsulant composition. By forming using the above composition, it becomes a solar cell encapsulant layer that can be sufficiently crosslinked and cured at the time of module laminating and that is prevented from being deteriorated even when exposed to ultraviolet rays for a long time.

  On the other hand, the solar cell module of the present invention is characterized by including a solar cell encapsulant layer formed using the solar cell encapsulant composition. Since the solar cell module has the solar cell encapsulant layer, the solar cell module can be sufficiently crosslinked and cured at the time of module lamination, and is a solar cell module in which deterioration is suppressed even when exposed to ultraviolet rays for a long time.

  Moreover, the solar cell module of this invention WHEREIN: It is preferable that the said photovoltaic cell is a crystalline silicon solar cell. The said solar cell module can improve photoelectric conversion efficiency more effectively by using it for the solar cell module which laminates | stacks the said photovoltaic cell.

The example of the solar cell module using the sealing material layer for solar cells of this invention is shown. The example of the solar cell module using the sealing material layer for solar cells of this invention is shown.

  Embodiments of the present invention will be described below.

(Encapsulant composition for solar cell)
The sealing material composition for solar cells of the present invention is characterized by comprising a dibutylhydroxytoluene (BHT) derivative and a hindered amine compound having a phenol skeleton in the molecule. The solar cell encapsulant composition may be formed by dispersing at least a dibutylhydroxytoluene (BHT) derivative and a hindered amine compound having a phenol skeleton in the molecule in an optically transparent matrix resin. it can. The solar cell encapsulant composition of the present invention contains the dibutylhydroxytoluene (BHT) derivative and the hindered amine compound so that the crosslinkable resin has sufficient crosslinkability even at the time of module lamination. Even if it is exposed to ultraviolet rays for a period of time, the UV-cutting property of the ultraviolet absorbing compound is maintained, and a sealing material layer for a solar cell, such as a matrix resin, which hardly changes color can be formed.

  Examples of the dibutylhydroxytoluene (BHT) derivative in the present invention include dibutylhydroxytoluene (BHT) and compounds obtained by chemically modifying a part or a part of the dibutylhydroxytoluene (BHT). Examples of the dibutylhydroxytoluene (BHT) derivative include neutral salts such as sodium salt and potassium salt of dibutylhydroxytoluene, derivatives on the benzene ring or partially substituted alkyl groups, and the like. Of these, dibutylhydroxytoluene (BHT) is preferably used.

  The molecular weight of the dibutylhydroxytoluene (BHT) is 220, but when the dibutylhydroxytoluene (BHT) derivative is used, the molecular weight of the derivative is preferably 220 to 500, and preferably 220 to 400. More preferably, it is 220-300. In addition, molecular weight measurement shall be based on MS spectrum.

  As a hindered amine compound having a phenol skeleton in the molecule of the present invention, it has a phenol skeleton in the molecule and directly captures radicals generated in the system by light irradiation or the like, and is conjugated with its own steric hindrance structure. An amine compound having the property of stopping (suppressing) the chain reaction of radicals by stabilizing radical species is used. Moreover, it is preferable that the said hindered amine type compound does not show an absorption maximum substantially in an ultraviolet wavelength (300-400 nm).

  The hindered amine compound preferably has a 2,2,6,6-tetramethyl-4-piperidyl structure. In addition, for example, an amine compound having a bulky substituent such as a t-butyl group so that other molecules are not easily accessible (sterically hindered) to the adjacent portion (such as o-position) of the hydroxyl group of the phenol skeleton. Etc.

  Examples of the hindered amine compound include bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl. Malonate (molecular weight: 685), 1- [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di -T-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine (molecular weight: 722). These compounds may be used alone or in combination of two or more.

  A commercial item can be used suitably as said hindered amine type compound. Examples of the hindered amine compound include Tinuvin 144 (molecular weight: 685, manufactured by BASF) and the like, all of which have a phenol skeleton in the molecule. These compounds may be used alone or in combination of two or more.

  Moreover, in the said solar cell sealing material composition, it is preferable that the molecular weights of the said hindered amine type compound are 400-4000, It is more preferable that it is 500-2000, It is further more preferable that it is 600-1000. When the molecular weight is less than 400, the hindered amine compound itself tends to bleed out. On the other hand, if the molecular weight is 4000 or more, problems such as compatibility with the matrix resin may occur. In addition, molecular weight measurement shall be based on MS spectrum.

  Further, in the solar cell encapsulant composition of the present invention, the matrix resin of the solar cell encapsulant composition contains an ethylene copolymer as a main component, and the dibutylhydroxy is added to 100 parts by weight of the matrix resin. The toluene derivative is preferably 0.001 to 0.2 parts by weight, more preferably 0.01 to 0.15 parts by weight, and still more preferably 0.02 to 0.1 parts by weight. By mix | blending in the said range, the function as an antioxidant can mainly be suitably obtained.

  Further, in the solar cell encapsulant composition of the present invention, the matrix resin of the solar cell encapsulant composition contains an ethylene copolymer as a main component, and the hindered amine system is used with respect to 100 parts by weight of the matrix resin. It is preferable that it is 0.001-0.3 weight part of a compound, It is more preferable that it is 0.005-0.1 weight part, It is further more preferable that it is 0.01-0.05 weight part. By mix | blending in the said range, the function as a light stabilizer can mainly be suitably obtained.

  Further, in the solar cell encapsulant composition of the present invention, the matrix resin of the solar cell encapsulant composition contains an ethylene copolymer as a main component, and the dibutylhydroxy is added to 100 parts by weight of the matrix resin. It is preferable that 0.001 to 0.2 part by weight of the toluene derivative and 0.001 to 0.3 part by weight of the hindered amine compound are included. In addition, 0.001 to 0.2 parts by weight of the dibutylhydroxytoluene derivative and 0.005 to 0.1 parts by weight of the hindered amine compound can be included, and the dibutylhydroxytoluene derivative can be added in an amount of 0.001. 001 to 0.2 parts by weight, and 0.01 to 0.05 parts by weight of the hindered amine compound can be included. The dibutylhydroxytoluene derivative can be contained in an amount of 0.01 to 0.15 parts by weight, and the hindered amine compound can be contained in an amount of 0.001 to 0.3 parts by weight. 01 to 0.15 parts by weight, and 0.005 to 0.1 parts by weight of the hindered amine compound, 0.01 to 0.15 parts by weight of the dibutylhydroxytoluene derivative, and The hindered amine compound can be contained in an amount of 0.01 to 0.05 parts by weight. The dibutylhydroxytoluene derivative can be contained in an amount of 0.02 to 0.1 parts by weight, and the hindered amine compound can be contained in an amount of 0.001 to 0.3 parts by weight. 02 to 0.1 parts by weight, and 0.005 to 0.1 parts by weight of the hindered amine compound, 0.02 to 0.1 parts by weight of the dibutylhydroxytoluene derivative, and The hindered amine compound can be contained in an amount of 0.01 to 0.05 parts by weight. By setting it as the said compounding quantity, inhibiting the bridge | crosslinking of matrix resin can be suppressed more effectively. As a result, the solar cell encapsulant layer formed of the composition can exhibit the effect of preventing oxidative degradation and suppressing light degradation over a long period of time without more reliably inhibiting crosslinking. Compared with the case where each component is added alone, the above-described effects are not limited to a mere total effect, but a synergistic effect can be obtained.

  The solar cell encapsulant composition preferably further includes a hindered amine compound having no phenol skeleton in the molecule. When the hindered amine compound is further used in combination, the solar cell encapsulant layer formed of the composition may easily exhibit the above-described oxidation deterioration preventing effect and light deterioration suppressing effect over a long period of time.

  A commercial item can be used suitably as a hindered amine type compound which does not have a phenol skeleton in the above-mentioned molecule. As a hindered amine compound having no phenol skeleton in the molecule, for example, bis- (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate (Tinuvin 123, manufactured by BASF, molecular weight 737) Tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) butane-1,2,3,4-tetracarboxylate (LA-52, ADEKA, molecular weight 847), tetrakis (2,2 , 6,6-pentamethyl-4-piperidyl) butane-1,2,3,4-tetracarboxylate (LA-57, manufactured by ADEKA, molecular weight 791), 1,2,3,4-butanetetracarboxylic acid Tetramethyl ester 1,2,2,6,6-pentamethyl-4-piperidinol β, β, β ′, β′-te Lamethyl-2,4,8,10-tetraoxaspiro [5,5] undecane-3,9-diethanol (LA-63P, manufactured by ADEKA, molecular weight of about 2000), 1,2,3,4-butanetetracarboxy Rick acid tetramethyl ester 2,2,6,6-pentamethyl-4-piperidinol β, β, β ′, β′-tetramethyl-2,4,8,10-tetraoxaspiro [5,5] undecane-3 , 9-diethanol (LA-68, manufactured by ADEKA, molecular weight of about 1900), bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (LA-72, manufactured by ADEKA, molecular weight 509), Bis- (2,2,6,6-tetramethyl-4-piperidyl) sebacate (LA-77Y, ADEKA, molecular weight 481), bis (2,2,6, -Tetramethyl-4-piperidyl) sebacate (LA-77G, manufactured by ADEKA, molecular weight 481), bis (1-undecanoxy-2,2,6,6-tetramethylpiperidin-4-yl) carbonate (LA-81, ADEKA, molecular weight 681), 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate (LA-82, ADEKA, molecular weight 239), 2,2,6,6-tetramethyl-4- Piperidyl methacrylate (LA-87, ADEKA, molecular weight 225), SONGLIGHT 1190 (SONGWON, molecular weight 2286), SONIGHT 1230 (SONGWON, molecular weight 737), bis (1,2,2,6,6-pentamethyl-4 -Piperidyl) sebacate (SONGLIGHT 2920, S NGWON, molecular weight 509), bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (SONGLIGHT 7700, SOGWON, molecular weight 481), poly (4-hydroxy-2,2,6,6) -Tetramethyl-1-piperidineethanol-ortho-1,4-butanedioic acid) (Uvinul 5062H, manufactured by BASF, molecular weight 3100-4000), Uvinul 5050H (manufactured by BASF, molecular weight 3000-4000), N, N'- Bisformyl-N, N′-bis (2,2,6,6-tetramethyl-4-piperidinyl) -hexamethylenediamine (Uvinul 4050H, manufactured by BASF, molecular weight 450), bis (2,2,6,6-tetra Methyl-4-piperidyl) sebacate (Uvinul 407) H, BASF Co., Ltd., molecular weight 481), and the like. These compounds may be used alone or in combination of two or more.

  Further, in the solar cell encapsulant composition of the present invention, the matrix resin of the solar cell encapsulant composition contains an ethylene copolymer as a main component, and the intramolecular amount relative to 100 parts by weight of the matrix resin. The hindered amine compound having no phenol skeleton is preferably 0.001 to 0.3 parts by weight, more preferably 0.005 to 0.1 parts by weight, and 0.01 to 0.05 parts by weight. More preferably, it is a part. By mix | blending in the said range, the function as a light stabilizer mainly may become easy to be obtained more suitably.

  As the solar cell encapsulant composition, an optically transparent matrix resin is preferably used. Examples of the matrix resin include polyolefins such as polyethylene terephthalate, poly (meth) acrylate, polyvinyl acetate, polyethylene tetrafluoroethylene, polyimide, amorphous polycarbonate, siloxane sol-gel, polyurethane, polystyrene, polyethersulfone, poly Examples include arylate, epoxy resin, and silicone resin. These matrix resins may be used alone or in admixture of two or more.

  Examples of the poly (meth) acrylate include polyacrylate and polymethacrylate, and examples thereof include (meth) acrylic acid ester resins. Examples of the polyolefin resin include polyethylene, polypropylene, and polybutadiene. Examples of the polyvinyl acetate include polyvinyl formal, polyvinyl butyral (PVB resin), and modified PVB.

  As a constituent monomer of the (meth) acrylic ester resin, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate (Meth) acrylic acid alkyl esters such as cyclohexyl acrylate, cyclohexyl methacrylate, phenyl acrylate, phenyl methacrylate, benzyl acrylate, and benzyl methacrylate. Furthermore, (meth) acrylic acid alkyl ester in which the alkyl group is substituted with a hydroxyl group, an epoxy group, a halogen group, or the like can be given. These compounds may be used alone or in combination of two or more.

  In the (meth) acrylic acid ester, the alkyl group in the ester moiety preferably has 1 to 20 carbon atoms, and more preferably 1 to 10 carbon atoms.

  As said (meth) acrylic acid ester resin, it is good also as a copolymer using the unsaturated monomer copolymerizable with these besides (meth) acrylic acid ester.

  Examples of the unsaturated monomer include unsaturated organic acids such as methacrylic acid and acrylic acid, styrene, α-methylstyrene, acrylamide, diacetone acrylamide, acrylonitrile, methacrylonitrile, maleic anhydride, phenylmaleimide, and cyclohexylmaleimide. I can give you. These unsaturated monomers may be used alone or in admixture of two or more.

  Among the above (meth) acrylic acid esters, among them, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, It is preferable to use 2-ethylhexyl methacrylate and its functional group-substituted (meth) acrylic acid alkyl ester. From the viewpoint of durability and versatility, methyl methacrylate is a more preferred example.

  Examples of the copolymer of the (meth) acrylic acid ester and the unsaturated monomer include (meth) acrylic acid ester-styrene copolymer, ethylene-vinyl acetate copolymer, and the like. In particular, from the viewpoint of moisture resistance, versatility, and cost, an ethylene copolymer is preferable, and an ethylene-vinyl acetate copolymer is more preferable, and in terms of durability and surface hardness, (meta ) Acrylic acid esters are preferred. Further, the combined use of an ethylene-vinyl acetate copolymer and a (meth) acrylic acid ester is preferable from the above viewpoints.

  The ethylene-vinyl acetate copolymer preferably has a vinyl acetate monomer unit content of 20 to 40 parts by weight with respect to 100 parts by weight of the ethylene-vinyl acetate copolymer. More preferably, the above content is preferable from the viewpoint of uniform dispersibility in a matrix resin such as a rare earth complex.

  When the ethylene-vinyl acetate copolymer is used as the optically transparent matrix resin, commercially available products can be used as appropriate. Commercially available products of the ethylene-vinyl acetate copolymer include, for example, Ultrasen (manufactured by Tosoh Corporation), Everflex (manufactured by Mitsui DuPont Polychemical Co., Ltd.), Suntec EVA (manufactured by Asahi Kasei Chemicals Corporation), UBE EVA copolymer ( Ube Maruzen Polyethylene Co., Ltd.), Evertate (Sumitomo Chemical Co., Ltd.), Novatec EVA (Nihon Polyethylene Co., Ltd.) and the like. These may be used singly or in combination of two or more.

  In the matrix resin, a crosslinkable monomer may be added to form a resin having a crosslinked structure.

  Examples of the crosslinkable monomer include compounds obtained by reacting α, β-unsaturated carboxylic acid with dicyclopentenyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, and polyhydric alcohol ( For example, polyethylene glycol di (meth) acrylate (having 2 to 14 ethylene groups), trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethoxytri (meth) acrylate, Trimethylolpropane propoxytri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, polypropylene glycol di (meth) acrylate (propiol Having 2 to 14 ren groups), dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, bisphenol A polyoxyethylene di (meth) acrylate, bisphenol A dioxyethylene di (meth) Acrylate, bisphenol A trioxyethylene di (meth) acrylate, bisphenol A decaoxyethylene di (meth) acrylate, etc.), a compound obtained by adding an α, β-unsaturated carboxylic acid to a glycidyl group-containing compound (for example, tri Methylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate, etc.), polyvalent carboxylic acid (for example, phthalic anhydride), a substance having a hydroxyl group and an ethylenically unsaturated group (for example, β-hydride) Esterified product with xylethyl (meth) acrylate), alkyl ester of acrylic acid or methacrylic acid (for example, (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) acrylic Acid 2-ethylhexyl ester), urethane (meth) acrylate (for example, reaction product of tolylene diisocyanate and 2-hydroxyethyl (meth) acrylic acid ester, trimethylhexamethylene diisocyanate, cyclohexanedimethanol and 2-hydroxyethyl (meth) A reaction product with an acrylate ester, etc.). These crosslinkable monomers may be used alone or in admixture of two or more. Of these, trimethylolpropane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and bisphenol A polyoxyethylene dimethacrylate are preferred as the crosslinkable monomer.

  When the matrix resin containing the crosslinkable monomer is used, for example, a thermal polymerization initiator or a photopolymerization initiator is added to the crosslinkable monomer, and polymerization and crosslinking can be performed by heating or light irradiation to form a crosslinked structure.

  A known peroxide can be appropriately used as the thermal polymerization initiator. Examples of the thermoplastic resin polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane-3, Di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, dicumyl peroxide, α, α'-bis (t-butylperoxy) Isopropyl) benzene, n-butyl-4,4-bis (t-butylperoxy) butane, 2,2-bis (t-butylperoxy) butane, 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, t-butylperoxybenzate, benzoyl peroxide, etc. be able to. These compounds may be used alone or in combination of two or more.

  For example, 0.1 to 5 parts by weight of the thermal polymerization initiator can be used with respect to 100 parts by weight of the matrix resin.

  As said photoinitiator, the well-known photoinitiator which produces | generates a free radical by an ultraviolet-ray or visible light can be used suitably. Examples of the photopolymerization initiator include benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, and benzoin phenyl ether, benzophenone, N, N′-tetramethyl-4,4′-diamino, and the like. Benzophenones (Michler ketone), benzophenones such as N, N′-tetraethyl-4,4′-diaminobenzophenone, benzyl ketals such as benzyldimethyl ketal (manufactured by Ciba Japan Chemicals, Irgacure 651), benzyl diethyl ketal, 2 , 2-dimethoxy-2-phenylacetophenone, p-tert-butyldichloroacetophenone, acetophenones such as p-dimethylaminoacetophenone, 2,4-dimethylthio Xanthones such as xanthone and 2,4-diisopropylthioxanthone, or hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals, Irgacure 184), 1- (4-isopropylphenyl) -2-vitoxy-2-methylpropane-1 -On (Ciba Japan Chemicals, Darocur 1116), 2-hydroxy-2-methyl-1-phenylpropan-1-one (Merck, Darocur 1173) and the like can be mentioned. These may be used singly or in combination of two or more.

  Further, as the photopolymerization initiator, for example, a combination of 2,4,5-triallylimidazole dimer and 2-mercaptobenzoxazole, leucocrystal violet, tris (4-diethylamino-2-methylphenyl) methane, etc. Etc. Further, for example, known additives may be used as appropriate, such as tertiary amines such as triethanolamine for benzophenone.

  The blending amount of the photopolymerization initiator can be 0.1 to 5 parts by weight with respect to 100 parts by weight of the matrix resin, for example.

  The refractive index of the matrix resin is, for example, in the range of 1.4 to 1.7, in the range of 1.45 to 1.65, or in the range of 1.45 to 1.55. In some embodiments, the refractive index of the polymer matrix material is 1.5.

  Moreover, it is preferable that the sealing material composition for solar cells of this invention contains an ultraviolet-absorbing compound further. As long as the UV-absorbing compound does not impair the cross-linkability, UV-cutting property, and anti-discoloration function of the solar cell encapsulant layer, the UV-absorbing compound that suppresses the suppression of UV degradation, as well as a wavelength conversion function is provided. An ultraviolet absorbing compound that can be used can be used.

  As the ultraviolet absorbing compound, known compounds can be appropriately used. Examples of the ultraviolet absorbing compound include benzophenone, benzotriazole, triazine, salicylic acid, and cyanoacrylate. These compounds may be used alone or in combination of two or more.

  Examples of the benzophenone-based ultraviolet absorbing compound include 2,2′-dihydroxy-4,4′-di (hydroxymethyl) benzophenone and 2,2′-dihydroxy-4,4′-di (2-hydroxyethyl) benzophenone. 2,2′-dihydroxy-3,3′-dimethoxy-5,5′-di (hydroxymethyl) benzophenone, 2,2′-dihydroxy-3,3′-dimethoxy-5,5′-di (2- Hydroxyethyl) benzophenone, 2,2′-dihydroxy-3,3′-di (hydroxymethyl) -5,5′-dimethoxybenzophenone, 2,2′-dihydroxy-3,3′-di (2-hydroxyethyl) -5,5'-dimethoxybenzophenone, 2,2-dihydroxy-4,4-dimethoxybenzophenone and the like can be mentioned.

  Examples of the benzotriazole ultraviolet absorbing compound include 2- [2′-hydroxy-5 ′-(hydroxymethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(2-hydroxy). Ethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(3-hydroxypropyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-methyl-5 ′ -(Hydroxymethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-3'-methyl-5 '-(2-hydroxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy -3'-methyl-5 '-(3-hydroxypropyl) phenyl] -2H-benzotriazole, 2- [2'-hydride Xy-3'-t-butyl-5 '-(hydroxymethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-3'-t-butyl-5'-(2-hydroxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-3'-t-butyl-5 '-(2-hydroxyethyl) phenyl] -5-chloro-2H-benzotriazole, 2- [2'-hydroxy- 3′-t-butyl-5 ′-(3-hydroxypropyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-t-octyl-5 ′-(hydroxymethyl) phenyl] -2H -Benzotriazole, 2- [2'-hydroxy-3'-t-octyl-5 '-(2-hydroxyethyl) phenyl] -2H-benzotriazole, 2- [2'- Droxy-3′-t-octyl-5 ′-(3-hydroxypropyl) phenyl] -2H-benzotriazole or the like, or 2,2′-methylenebis [6- (2H-benzotriazoly-2-yl) -4- ( Hydroxymethyl) phenol], 2,2'-methylenebis [6- (2H-benzotriazoly-2-yl) -4- (2-hydroxyethyl) phenol], 2,2'-methylenebis [6- (5-chloro- 2H-benzotriazoly-2-yl) -4- (2-hydroxyethyl) phenol], 2,2′-methylenebis [6- (5-bromo-2H-benzotriazoly-2-yl) -4- (2-hydroxyethyl) ) Phenol], 2,2'-methylenebis [6- (2H-benzotriazoly-2-yl) -4- (3-hydroxypropyl) pheno 2,2′-methylenebis [6- (5-chloro-2H-benzotriazoly-2-yl) -4- (3-hydroxypropyl) phenol], 2,2′-methylenebis [6- (5-bromo) -2H-benzotriazoly-2-yl) -4- (3-hydroxypropyl) phenol], 2,2'-methylenebis [6- (2H-benzotriazoly-2-yl) -4- (4-hydroxybutyl) phenol] 2,2′-methylenebis [6- (5-chloro-2H-benzotriazoly-2-yl) -4- (4-hydroxybutyl) phenol], 2,2′-methylenebis [6- (5-bromo-2H -Benzotriazoly-2-yl) -4- (4-hydroxybutyl) phenol], 3,3- {2,2'-bis [6- (2H-benzotriazoly-2-yl)- -Hydroxy-4- (2-hydroxyethyl) phenyl]} propane, 2,2- {2,2'-bis [6- (2H-benzotriazoli-2-yl) -1-hydroxy-4- (2-hydroxy) Ethyl) phenyl]} butane, 2,2′-oxybis [6- (2H-benzotriazoly-2-yl) -4- (2-hydroxyethyl) phenol], 2,2′-bis [6- (2H-benzotriazolyl) -2-yl) -4- (2-hydroxyethyl) phenol] sulfide, 2,2′-bis [6- (2H-benzotriazoly-2-yl) -4- (2-hydroxyethyl) phenol] sulfoxide, 2 2,2'-bis [6- (2H-benzotriazoly-2-yl) -4- (2-hydroxyethyl) phenol] sulfone, 2,2'-bis [6- (2H-ben Toriazori 2-yl), etc. -4- (2-hydroxyethyl) phenol] amine can be exemplified.

  Examples of the triazine-based ultraviolet absorbing compound include 2- (2-hydroxy-4-hydroxymethylphenyl) -4,6-diphenyl-s-triazine and 2- (2-hydroxy-4-hydroxymethylphenyl) -4. , 6-Bis (2,4-dimethylphenyl) -s-triazine, 2- [2-hydroxy-4- (2-hydroxyethyl) phenyl] -4,6-diphenyl-s-triazine, 2- [2- Hydroxy-4- (2-hydroxyethyl) phenyl] -4,6-bis (2,4-dimethylphenyl) -s-triazine, 2- [2-hydroxy-4- (2-hydroxyethoxy) phenyl] -4 , 6-Diphenyl-s-triazine, 2- [2-hydroxy-4- (2-hydroxyethoxy) phenyl] -4,6-bis (2,4-dimethyl) Enyl) -s-triazine, 2- [2-hydroxy-4- (3-hydroxypropyl) phenyl] -4,6-diphenyl-s-triazine, 2- [2-hydroxy-4- (3-hydroxypropyl) Phenyl] -4,6-bis (2,4-dimethylphenyl) -s-triazine, 2- [2-hydroxy-4- (3-hydroxypropoxy) phenyl] -4,6-diphenyl-s-triazine, 2 -[2-hydroxy-4- (3-hydroxypropoxy) phenyl] -4,6-bis (2,4-dimethylphenyl) -s-triazine, 2- [2-hydroxy-4- (4-hydroxybutyl) Phenyl] -4,6-diphenyl-s-triazine, 2- [2-hydroxy-4- (4-hydroxybutyl) phenyl] -4,6-bis (2,4-dimethyl) Enyl) -s-triazine, 2- [2-hydroxy-4- (4-hydroxybutoxy) phenyl] -4,6-diphenyl-s-triazine, 2- [2-hydroxy-4- (4-hydroxybutoxy) Phenyl] -4,6-bis (2,4-dimethylphenyl) -s-triazine, 2- (2-hydroxy-4-hydroxymethylphenyl) -4,6-bis (2-hydroxy-4-methylphenyl) -S-triazine, 2- [2-hydroxy-4- (2-hydroxyethyl) phenyl] -4,6-bis (2-hydroxy-4-methylphenyl) -s-triazine, 2- [2-hydroxy- 4- (2-hydroxyethoxy) phenyl] -4,6-bis (2-hydroxy-4-methylphenyl) -s-triazine, 2- [2-hydroxy-4- (3-H Droxypropyl) phenyl] -4,6-bis (2-hydroxy-4-methylphenyl) -s-triazine, 2- [2-hydroxy-4- (3-hydroxypropoxy) phenyl] -4,6-bis (2-hydroxy-4-methylphenyl) -s-triazine, 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) Examples thereof include phenol and 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol.

  Examples of the salicylic acid-based ultraviolet absorbing compound include phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, and the like.

  Examples of the cyanoacrylate-based ultraviolet absorbing compound include 2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate, ethyl-2-cyano-3,3'-diphenyl acrylate, and the like.

  Moreover, when using what has a wavelength conversion function to the said ultraviolet absorption compound, the fluorescent compound which absorbs more light of the wavelength range 350-400 nm than the light of the wavelength range exceeding 400 nm as the said ultraviolet absorption compound is mention | raise | lifted, for example. be able to. Examples of the fluorescent compound include organic fluorescent compounds and inorganic fluorescent compounds.

  As the organic fluorescent compound, a known organic coloring compound (such as an organic fluorescent dye) can be used. Examples of the organic fluorescent compound include naphthalimide, perylene, anthraquinone, coumarin, benzocoumarin, xanthene, phenoxazine, benzo [a] phenoxazine, benzo [b] phenoxazine, benzo [c] phenoxazine, and naphthalimide. , Naphtholactam, azlactone, methine, oxazine, thiazine, diketopyrrolopyrrole, quinacridone, benzoxanthene, thioepiindrin, lactamimide, diphenylmaleimide, acetoacetamide, imidazothiazine, benzanthrone, perylenemonoimide, phthalimide, benzotriazole Benzothiadiazole, benzoxazole, pyrimidine, pyrazine, triazole, dibenzofuran, triazine, harbituric acid derivatives, etc. It can be. These compounds may be used alone or in combination of two or more.

  Examples of the inorganic fluorescent compound include complex compounds having europium or samarium as the emission center. These compounds may be used alone or in combination of two or more.

  The absorbance of the fluorescent compound is, for example, preferably from 0.1 to 6, more preferably from 0.5 to 4, and even more preferably from 0.8 to 3.

  The ultraviolet absorbing compound preferably has a maximum absorption wavelength in the range of 200 to 400 nm, particularly 280 to 380 nm. By using the ultraviolet absorbing compound, it is possible to more effectively absorb ultraviolet rays that may cause photodegradation of an ethylene copolymer such as an ethylene-vinyl acetate copolymer, among ultraviolet rays contained in irradiation light. In addition, the maximum absorption wavelength of the said ultraviolet absorption compound can be measured using a commercially available ultraviolet ray measuring apparatus etc. using a well-known method.

  Among the above ultraviolet absorbing compounds, it is preferable to use a benzophenone-based ultraviolet absorbing compound from the viewpoint of preventing photodegradation of an ethylene-vinyl acetate copolymer, and a benzophenone-based ultraviolet absorbing containing two or less hydroxyl groups in one molecule. It is particularly preferred to use a compound. Examples of the ultraviolet absorbing compound include 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-n-octoxy-benzophenone. The said compound has the maximum absorption wavelength in the range of 320-350 nm, and can suppress the photodegradation of an ethylene-vinyl acetate copolymer more effectively.

  The content of the ultraviolet absorbing compound is preferably 0.001 to 1 part by weight, more preferably 0.01 to 0.8 part by weight, with respect to 100 parts by weight of the matrix resin. More preferably, it is -0.5 weight part.

  In the solar cell encapsulant composition, the respective components (compounds) are mixed and dispersed in the matrix resin. The solar cell encapsulant composition may contain a known additive as long as the desired performance is not impaired. Examples of the additive include thermoplastic polymers, antioxidants, UV inhibitors, light stabilizers, organic peroxides, fillers, plasticizers, silane coupling agents, acid acceptors, and clays. These may be used singly or in combination of two or more.

(Sealant layer for solar cells)
On the other hand, the solar cell encapsulant layer of the present invention is formed using the above solar cell encapsulant composition.

  What is necessary is just to perform according to a well-known method in order to manufacture the said sealing material layer for solar cells. For example, a composition obtained by mixing the above-described solar cell encapsulant composition (or each material thereof) with a known method using heat kneading, a super mixer (high-speed fluidized mixer), a roll mill, a plast mill, etc. It can be suitably manufactured by a method of forming a sheet by molding by extrusion molding, calendar molding (calendering), vacuum hot pressing or the like. Moreover, after forming the said layer on PET film etc., it can manufacture by the method of transcribe | transferring to a surface protective layer. Further, a method of simultaneously kneading and melting and applying with a hot melt applicator can be used.

  More specifically, for example, the solar cell encapsulant composition containing the matrix resin, the dibutylhydroxytoluene derivative, the hindered amine compound, and the like may be applied and formed as it is on a surface protective layer or a separator. The above material may be applied and formed as a mixed composition with other materials.

  When applied as the solar cell encapsulant composition, the matrix resin preferably has a melting point of 50 to 120 ° C., more preferably 50 to 100 ° C., in consideration of processability. More preferably, it is -80 degreeC. For example, when the melting point of the solar cell encapsulant composition is 50 to 120 ° C., the kneading and melting and coating temperature of the composition are preferably performed at a temperature obtained by adding 30 to 100 ° C. to the melting point.

  Also, in some embodiments, the solar cell encapsulant layer is manufactured into a thin film structure by the following steps: (i) The polymer (matrix resin) powder is a solvent (eg, tetrachloroethylene (TCE) in a predetermined ratio. ), Preparing a polymer solution dissolved in cyclopentanone, dioxane, etc.) (ii) mixing a luminescent dye (fluorescent compound) containing the polymer mixture with the luminescent dye in a predetermined weight ratio Preparing a dye-containing polymer solution, (iii) pouring the dye / polymer thin film directly onto the glass substrate, after which the substrate is allowed to rise from room temperature up to 100 ° C. in 2 hours Forming by heat treating and completely removing the residual solvent by further vacuum heating at 130 ° C. overnight; and (Iv) peeling the dye / polymer thin film in water before use and then completely drying the free-standing polymer film; (v) determining the film thickness, dye / polymer solution concentration and evaporation rate. It can be controlled by changing.

  The thickness of the solar cell encapsulant layer is preferably 20 to 2000 μm, more preferably 50 to 1000 μm, and still more preferably 100 to 800 μm. When the thickness is less than 20 μm, the sealing material function is hardly exhibited. On the other hand, when it becomes thicker than 2000 micrometers, the thickness of a solar cell module will become large and it will be disadvantageous also in cost.

  The solar cell encapsulant layer is usually used for encapsulating solar cells, and is laminated so as to appropriately seal interconnector materials, electrodes, and the like as necessary. As long as the function of the solar cell encapsulant layer is not impaired, other layers such as each layer may be interposed as required.

(Solar cell module)
The solar cell module 1 of the present invention includes a surface protective layer 10, the solar cell sealing material layer 20, and solar cells 30. 1 and 2 show simple schematic diagrams as an example, but the present invention is not limited to these. Moreover, the sealing material layer 40 and the back sheet | seat 50 can also be further suitably provided in the back side of a photovoltaic cell. Moreover, as long as the said function of the said solar cell sealing material layer is not impaired between these each layers, you may interpose other layers, such as an adhesive material layer and an adhesive layer, suitably. Moreover, you may use the sealing material layer for solar cells of this invention suitably as said sealing material layer for back surfaces.

  As the solar cell, for example, a cadmium sulfide / cadmium telluride solar cell, a copper indium gallium diselenide solar cell, an amorphous silicon solar cell, a microcrystalline silicon solar cell, or a crystalline silicon solar cell can be used. The solar battery cell is preferably a crystalline silicon solar battery.

  In the production of the solar cell module, the solar cell encapsulant layer may be transferred to the solar cell or the like, or may be directly coated on the solar cell. Moreover, you may form the said sealing material layer for solar cells, and another layer simultaneously.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below.

(Compounds in the table)
In the examples and comparative examples, the following compounds were used.
・ Matrix resin: Summitate KA-30, ethylene vinyl acetate resin (Sumitomo Chemical Co., Ltd.)
Organic compound A: 4,7-bis (4-isobutyloxyphenyl) -2-isobutyl-2H-benzotriazolePeroxide: t-butylperoxy-2-ethylhexyl monocarbonate (manufactured by NOF Corporation, perbutyl E)
・ Crosslinking aid: triallyl isocyanate (manufactured by Nippon Kasei Co., Ltd., TAIC)
・ BHT: Dibutylhydroxytoluene (manufactured by Tokyo Chemical Industry Co., Ltd.)
Tinuvin 144: bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate (BASF) (Made in Japan, molecular weight 685)
Tinuvin 770DF: bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (BASF, molecular weight 481)
KBM503: 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Silicone)

(Production of resin sheet)
In Examples and Comparative Examples, each sealing material layer (sealing sheet and backside sealing sheet) was produced by the following method, based on the compounds shown in Table 1.

  In each Example / Comparative Example, 100 parts by weight of EVA resin (Smitate KA-30) and each compound were weighed, dry blended, melt-kneaded using a single screw extruder, and pellets of an ethylene copolymer composition. Got. A sealing material layer resin sheet (thickness: about 400 μm) was produced from the pellets using a press molding machine.

(Measurement of gel fraction)
A sample in which a PET release film was attached to both sides of the obtained encapsulant layer resin sheet (thickness: 400 μm) was sandwiched between glass and a back sheet, pressed under conditions of 80 ° C. and 100 kN, and 150 ° C. The conditions were stored in a drying oven for 20 minutes. Thereafter, W ₁ g was cut and precisely weighed and immersed in 100 cc of xylene (110 ° C., 24 hours). Thereafter, the weight W ₂ g after drying of the filtration residue (80 ° C., 6 hours) was precisely weighed, and the value calculated as (W ₂ / W ₁ ) × 100 was taken as the gel fraction (wt%). The evaluation criteria were as follows.
When the average value of gel fraction (measured number 2) is 80% or more: ○
When the average value of gel fraction (measured number is 2) is less than 80%: ×

(Evaluation of initial yellowing)
The obtained encapsulant layer resin sheet (thickness: 400 μm) was sandwiched between glass and a back sheet, and bonded at 80 ° C. and 100 kN, and stored in a drying oven at 150 ° C. for 20 minutes. Thereafter, UV light (365 nm) of 1 W / cm ² was irradiated for a predetermined time (180 minutes) using a UV irradiator (Panasonic Electric Works Control Co., UJ35) and a lens (Panasonic Electric Works Control Co., ANUJ6426). The reflection spectrum of the sample before and after UV light irradiation was measured by MCPD (manufactured by Otsuka Electronics Co., Ltd.). The yellowing degree (YI: Yellow Index, ASTM D 1925) was calculated from the obtained reflection spectrum information, and yellowing evaluation was performed. The evaluation criteria were as follows.
-When the average value of the measured values at the four points at the end is less than 7.5:
When the average value of the measured values at the four points at the end is 7.5 or more and less than 10: Δ
When the average value of the measured values at the four points at the end is 10 or more: ×

(Light stability test)
The obtained encapsulant layer resin sheet (thickness: 400 μm) is sandwiched between glass and a PET release film and bonded at 80 ° C. and 100 kN, and stored in a drying oven at 150 ° C. for 20 minutes. did. Thereafter, the release film is peeled off, and using a UV irradiator (Panasonic Electric Works Control Co., Ltd., UJ35) and a lens (Panasonic Electric Works Control Co., Ltd., ANUJ6426), 1 W / cm ² of UV light (365 nm) is given from both sides of the sheet. Irradiated for a time (120 minutes). The absorption spectrum of the sample before and after light irradiation was measured with a spectrophotometer (manufactured by JASCO Corporation, V560). From the obtained spectral information, the change in absorbance of the organic substance was evaluated. The evaluation criteria were as follows.
・ When the change in absorbance after UV irradiation is −0.8 or more: ○
・ When the change in absorbance after irradiation with ultraviolet rays is −0.9 or more and less than −0.8: Δ
When the change in absorbance after irradiation with ultraviolet rays is less than −0.9: ×

Table 1 below shows each measurement result when the obtained sealing material layer resin sheet was used.

  As a result of the measurement, in the comparative example, when only one of dibutylhydroxytoluene or Tinuvin 144 was added and when neither dibutylhydroxytoluene or Tinuvin 144 was included, yellowing due to ultraviolet irradiation was likely to occur. It was found that the light stability of the organic matter was also low. On the other hand, in the examples of the present application, since dibutylhydroxytoluene or Tinuvin 144 is used in combination, yellowing hardly occurs and the light stability is enhanced. Compared with the case where each component was added alone, the above-mentioned effects were not limited to a mere total effect, and a synergistic effect was obtained.

DESCRIPTION OF SYMBOLS 1 Solar cell module 10 Surface protective layer 20 Solar cell sealing material layer 30 Solar cell 40 Back surface sealing material layer 50 Back sheet

Claims (11)

  A sealing material composition for solar cells, comprising a dibutylhydroxytoluene (BHT) derivative and a hindered amine compound having a phenol skeleton in the molecule.   The solar cell sealing material composition according to claim 1, wherein the hindered amine compound has a dibutylhydroxytoluene skeleton.   The sealing material composition for solar cells of Claim 1 or 2 whose molecular weight of the said hindered amine type compound is 400-4000.   The solar cell encapsulant composition according to any one of claims 1 to 3, wherein the hindered amine compound has a 2,2,6,6-tetramethyl-4-piperidyl structure.   Furthermore, the hindered amine compound which does not have a phenol skeleton in a molecule | numerator is contained, The solar cell sealing material composition in any one of Claims 1-4 characterized by the above-mentioned.   The matrix resin of the solar cell encapsulant composition is mainly composed of an ethylene copolymer, and 0.001 to 0.2 parts by weight of the dibutylhydroxytoluene derivative with respect to 100 parts by weight of the matrix resin, and The sealing material composition for solar cells in any one of Claims 1-5 containing the said hindered amine type compound 0.001-0.3 weight part.   Furthermore, the sealing material composition for solar cells in any one of Claims 1-6 containing a ultraviolet absorption compound.   The solar cell encapsulant composition according to claim 1, wherein the matrix resin contains an ethylene-vinyl acetate copolymer as a main component.   The solar cell sealing material layer formed using the solar cell sealing material composition in any one of Claims 1-8.   The solar cell module containing the sealing material layer for solar cells formed using the sealing material composition for solar cells in any one of Claims 1-8.   The solar cell module according to claim 10, wherein the solar cell is a crystalline silicon solar cell.

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