JP2012209474A - Adhesive sheet for solar cell and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive sheet for solar cell which has excellent adhesiveness and is capable of stably sealing solar cell elements for a long period of time.SOLUTION: An adhesive sheet A for solar cell of the present invention is an adhesive sheet for solar cell in which three or more of resin layers containing ethylene-based copolymer and organic peroxide are integrally laminated, in which at least one resin layer 1a out of resin layers 1a other than resin layers 1b and 1b being outermost layers contains light stabilizer, and the resin layers 1b and 1b being outermost layers on both sides contain 0.05 to 3 pts.wt. of silane coupling agent with respect to 100 pts.wt. of ethylene-based copolymer and do not contain hindered amin-based radical scavenger.

Description

  The present invention relates to an adhesive sheet for a solar cell used when producing a solar cell module and a method for producing the same.

  A solar cell module consisting of a silicon or selenium semiconductor wafer has a reduced pressure on a laminate obtained by overlaying a transparent protective material on the upper surface of a solar cell element with a solar cell adhesive sheet laminated on both sides and a back surface protective material on the lower surface. It is manufactured by heating while degassing below and stacking and integrating the protective material on the upper and lower surfaces of the solar cell element via an adhesive sheet.

  As an adhesive sheet for a solar cell used in such a solar cell module, for example, Patent Document 1 discloses a solar cell sealing sheet constituted by a sheet formed by forming a transparent soft resin composition containing a silane coupling agent. As a stopping film, a solar cell sealing film in which the silane coupling agent contains a polysiloxane compound has been proposed.

  However, when a hindered amine radical scavenger is used, the solar cell sealing film is used by including the hindered amine radical scavenger in a resin layer containing a silane coupling agent. Hydrolysis is caused by the action of the hindered amine radical scavenger, and as a result, the adhesion of the solar cell sealing film decreases with time, and the weather resistance of the solar cell module obtained using the solar cell sealing film and There is a problem that durability is low.

JP 2000-183382 A

  This invention provides the adhesive sheet for solar cells which has the adhesiveness outstanding over the long term, and its manufacturing method.

  The adhesive sheet for solar cells of the present invention is an adhesive sheet for solar cells in which three or more resin layers containing an ethylene-based copolymer and an organic peroxide are laminated and integrated. At least one of the removed resin layers contains a light stabilizer, and the resin layer serving as the outermost layers on both sides is provided with a silane coupling agent 0. It contains 05 to 3 parts by weight and does not contain a hindered amine radical scavenger.

  The method for producing an adhesive sheet for a solar cell of the present invention includes supplying a resin composition containing an ethylene copolymer and an organic peroxide to a plurality of extruders, melt-kneading each, and connecting all the above-mentioned extruders A manufacturing method of manufacturing an adhesive sheet for a solar cell, in which three or more resin layers made of the resin composition are laminated and integrated by supplying the resin composition to a T-die and co-extrusion. At least one of the resin compositions supplied to the extruder contains a light stabilizer, and this resin composition is at least one of the remaining resin layers excluding the outermost resin layer. The resin composition that constitutes the resin layer and the outermost resin layer contains 0.05 to 3 parts by weight of a silane coupling agent with respect to 100 parts by weight of the ethylene copolymer and is a hindered amine La Characterized in that not containing a local scavenger.

  Since the adhesive sheet for solar cells of the present invention has the above-described configuration, the silane coupling agent in the resin layer constituting the outermost layers on both sides is decomposed by the action of the hindered amine radical scavenger. In other words, the adhesiveness is stably maintained over a long period of time by the action of the silane coupling agent, and thus the solar cell element can be reliably sealed over a long period of time.

It is the longitudinal cross-sectional view which showed the adhesive sheet for solar cells of this invention. It is a longitudinal cross-sectional view of the solar cell module using the adhesive sheet for solar cells of this invention. It is a longitudinal cross-sectional view of the solar cell module using the adhesive sheet for solar cells of this invention.

  An example of the adhesive sheet for solar cells of the present invention will be described with reference to the drawings. As shown in FIG. 1, the adhesive sheet A for solar cells is formed by laminating and integrating three or more resin layers 1, 1... Containing an ethylene copolymer and an organic peroxide.

  Each resin layer 1a, 1b of the adhesive sheet A for solar cells contains an ethylene copolymer and an organic peroxide. The ethylene-based copolymer is a copolymer of ethylene and a copolymerizable monomer that can be copolymerized with ethylene. Such a copolymerizable monomer is not particularly limited, and examples thereof include vinyl acetate and acrylic monomers. Examples include acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, maleic acid, maleic anhydride, maleic acid ester, and propylene, and vinyl acetate is preferable. In addition, the said copolymerizable monomer may be copolymerized with ethylene independently, or 2 or more types may be copolymerized with ethylene.

  If the amount of the copolymerizable monomer contained in the ethylene-based copolymer is small, the transparency of the solar cell adhesive sheet may be lowered. Further, the mechanical strength may be insufficient, so that it is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and particularly preferably 14 to 35% by weight.

  If the melt flow rate of the ethylene copolymer is small, the film-forming stability of the adhesive sheet for solar cells may be reduced. If the melt flow rate is large, the mechanical strength of the adhesive sheet for solar cells becomes insufficient. Therefore, 1 to 100 g / 10 min is preferable. The melt flow rate of the ethylene copolymer in the present invention refers to a value measured under conditions of a temperature of 190 ° C. and a load of 2.16 kgf (21.18 N) according to JIS K7210.

  The solar cell adhesive sheet A is used by being disposed on the upper and lower surfaces of the solar cell element at the time of manufacturing the solar cell module. The solar cell element is sealed and integrated by thermocompression bonding under reduced pressure. The element and a protective material disposed on the upper and lower surfaces of the solar cell element via a solar cell adhesive sheet are bonded. Among the adhesives and heat resistance particularly required for the adhesive sheet for solar cells, the ethylene-based copolymer has a problem that heat resistance is low although it is excellent in adhesiveness. Accordingly, an organic peroxide is contained in the ethylene copolymer constituting the adhesive sheet A for solar cells, and the ethylene copolymer is crosslinked by heat applied during the production of the solar cell module. The heat resistance of the adhesive sheet A is improved.

  Examples of the organic peroxide used for the resin layer 1 include dicumyl peroxide (136 ° C.), t-butylperoxy-2-ethylhexyl monocarbonate (119 ° C.), and t-butyl peroxybenzoate (125 ° C.). 1,1-di (t-butylperoxy) -2-methylcyclohexane (102 ° C.), 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane (106 ° C.), 1 , 1-di (t-hexylperoxy) cyclohexane (107 ° C.), 1,1-di (t-butylperoxy) cyclohexane (111 ° C.), 2,2-di (4,4-di (t-butyl) Peroxy) cyclohexyl) propane (114 ° C.), t-hexyl peroxyisopropyl monocarbonate (115 ° C.), t-butyl peroxyisopropyl Lumonocarbonate (118 ° C), t-butylperoxylaurate (118 ° C), 2,5-dimethyl-2,5-di (benzoylperoxy) hexane (119 ° C), t-hexylperoxybenzoate (119 ° C) ), T-butylperoxymaleic acid (119 ° C.), t-butylperoxy-3,5,5-trimethylhexanoate (119 ° C.), t-butylperoxyacetate (121 ° C.), 2,2- Di (t-butylperoxy) butane (122 ° C.), n-butyl-4,4-di (t-butylperoxy) valerate (127 ° C.), di-t-hexyl peroxide (136 ° C.), t- Butyl cumyl peroxide (137 ° C.), di (2-t-butylperoxyisopropyl) benzene (138 ° C.), 2,5-dimethyl-2,5-di ( -Butylperoxy) hexane (138 ° C.), di-t-butyl peroxide (144 ° C.), 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 (150 ° C.), p -Menthane hydroperoxide (151 degreeC) etc. are mentioned, It may be used independently or 2 or more types may be used together. The temperature in the parenthesis represents a 1 hour half-life temperature.

  If the amount of the organic peroxide contained in the resin layer 1 is small, the crosslinking of the ethylene copolymer becomes insufficient during the production of the solar cell module, and the heat resistance of the adhesive sheet for solar cells is reduced. Insufficient durability of the solar cell module obtained due to the shortage, when many, when the adhesive sheet for solar cells is formed, the resin layer cross-links and stays in the T-die and adheres to the solar cell with a uniform thickness The sheet cannot be obtained, or the ethylene copolymer is solidified in the T-die and the solar cell adhesive sheet cannot be extruded. 0.05 to 3 parts by weight are preferred.

  The resin layer 1 may contain a crosslinking aid. Examples of the crosslinking aid include polyfunctional monomers having two or more allyl groups, vinyl groups, acryloyl groups or methacryloyl groups, which stabilize polymer radicals to increase crosslinking efficiency and concentrate crosslinking points. Accelerates gel formation. Examples of the polyfunctional monomer include diallyl phthalate, diallyl itaconate, diallyl maleate, triallyl isocyanurate, triallyl cyanurate, triallyl phosphate, divinylbenzene; 1,6-hexanediol di (meth) acrylate (Meth) such as ethylene oxide modified bisphenol A di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ε-caprolactone modified dipentaerythritol Examples thereof include acrylates and (meth) acrylates of alkyl-modified dipentaerythritol, which may be used alone or in combination of two or more.

  If the amount of the crosslinking aid contained in the resin layer 1 is small, the crosslinking of the solar cell adhesive sheet may be insufficient during the production of the solar cell module. Since it becomes too hard and hard, excessive stress is applied to the solar cell element, which may not be preferable for protecting the solar cell element. 01 to 1 part by weight is preferred.

  The adhesive sheet A for solar cells of the present invention excludes at least one resin layer 1a of the resin layers 1a, 1a ... except the resin layer 1b serving as the outermost layer, and preferably excludes the resin layer 1b serving as the outermost layer. All of the resin layers 1a, 1a,... Contain a light stabilizer in order to provide the solar cell adhesive sheet A with excellent weather resistance over a long period of time.

  Light stabilizers include ultraviolet absorbers that absorb the energy of ultraviolet rays to prevent the generation of radicals, and radical scavengers that trap the generated radicals, and give excellent weather resistance to solar cell adhesive sheets. Radical scavengers are preferred.

  The ultraviolet absorber is not particularly limited, and examples thereof include 2- (5-methyl-2-hydroxyphenyl) benzotriazole and 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chloro. Examples include benzotriazole ultraviolet absorbers such as benzotriazole, and benzophenone ultraviolet absorbers such as 2-hydroxy-4-octoxybenzophenone. In addition, an ultraviolet absorber may be used independently or 2 or more types may be used together.

  Examples of the radical scavenger include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate. Bis (1-methoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1-ethoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1-propoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1-butoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1-pentyloxy) -2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1-hexyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1-heptyloxy- , 2,6,6-tetramethyl-4-piperidi-piperidyl) sebacate, bis (1-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1-nonyloxy-2,2 , 6,6-tetramethyl-4-piperidyl) sebacate, bis (1-decanyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1-dodecyloxy-2,2,6,6) -Tetramethyl-4-piperidyl) sebacate, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2, Hindered amine radical scavengers such as 6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] are preferred. Ku, bis (2,2,6,6-tetramethyl-4-piperidyl) Sebake - bets are more preferred. In addition, a radical scavenger may be used independently or 2 or more types may be used together.

  If the content of the light stabilizer in the resin layer 1a excluding the outermost resin layer 1b is small, the weather resistance of the solar cell adhesive sheet may be lowered. If the content is large, the light stabilizer is used for solar cells. Since it may bleed out on the surface of the adhesive sheet and the adhesiveness of the adhesive sheet for solar cells may be reduced, 0.05 to 2 parts by weight is preferable with respect to 100 parts by weight of the ethylene-based copolymer. 0.5 parts by weight is more preferable.

  The resin layer 1a excluding the resin layer 1b that is the outermost layer may or may not contain a silane coupling agent.

  When the silane coupling agent is contained in the resin layer 1a excluding the outermost resin layer 1b, if the content of the silane coupling agent in each resin layer 1a is large, the crosslinking of the ethylene-based copolymer is caused. And the heat resistance of the adhesive sheet for solar cells may be reduced, so that it is preferably 0.5 parts by weight or less, more preferably 0.3 parts by weight or less with respect to 100 parts by weight of the ethylene copolymer.

  The resin layer 1a excluding the resin layer 1b, which is the outermost layer of the solar cell adhesive sheet, may contain additives such as scorch inhibitors and antioxidants as long as the physical properties are not impaired. .

  On the other hand, in the production of a solar cell module, a transparent protective material such as a glass plate is laminated and integrated on the surface (light-receiving surface) of the solar cell element via a solar cell adhesive sheet, and the solar cell is formed on the back surface of the solar cell element. Although the back surface protective material is laminated and integrated through the adhesive sheet for use, these protective materials, in particular, the adhesiveness between the transparent protective material and the solar cell adhesive sheet, and the solar cell adhesive sheet and the solar cell element The adhesion of the solar cell element and the protective material is strengthened, and the sealing property of the solar cell element by the solar cell adhesive sheet is improved and the sealing state is maintained for a long period of time. In order to maintain it stably over time, the resin layers 1b and 1b, which are the outermost layers on both sides of the adhesive sheet for solar cells, contain a silane coupling agent.

  As the silane coupling agent, a silane coupling agent having one or two or more functional groups selected from the group consisting of an amino group, a glycidyl group, a methacryloxy group and a mercapto group is preferably used. Propyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like, and a group consisting of amino group, glycidyl group, methacryloxy group and mercapto group A trialkoxysilane having one or more functional groups selected from the above is preferred, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane are more preferred, 3-aminop Pills triethoxysilane, 3-glycidoxypropyltrimethoxysilane is particularly preferred. In addition, a silane coupling agent may be used independently or 2 or more types may be used together.

  If the content of the silane coupling agent in the resin layers 1b and 1b which are the outermost layers on both sides of the adhesive sheet A for solar cells is small, the adhesiveness of the adhesive sheet for solar cells is reduced. Therefore, the amount is limited to 0.05 to 3 parts by weight, preferably 0.07 to 1 part by weight, based on 100 parts by weight of the ethylene copolymer.

  The silane coupling agents contained in the resin layers 1b and 1b that are the outermost layers on both sides of the solar cell adhesive sheet A may be the same or different, but when using the solar cell adhesive sheet, It is not necessary to distinguish between both surfaces of the solar cell adhesive sheet, and the handleability of the solar cell adhesive sheet is improved. Therefore, it is preferable that they are the same, and the resin that is the outermost layers on both sides of the solar cell adhesive sheet A The content of the silane coupling agent contained in the layers 1b and 1b may be the same or different, but when using the solar cell adhesive sheet, distinguish both sides of the solar cell adhesive sheet. Since it is not necessary to use and the handleability of the adhesive sheet for solar cells is improved, the same amount is preferable.

  When the hindered amine radical scavenger coexists in the silane coupling agent contained in the resin layers 1b and 1b which are the outermost layers on both sides described above, the hindered amine radical scavenger is hydrolyzed by the action of the hindered amine radical scavenger. Since the adhesiveness of the adhesive sheet is lowered, the hindered amine radical scavenger is not contained in the resin layers 1b and 1b which are the outermost layers on both sides in the adhesive sheet for solar cell of the present invention. Since the hindered amine radical scavenger is the same as described above, the description thereof is omitted.

  In addition, to the resin layers 1b and 1b constituting the adhesive sheet for solar cells, addition of a light stabilizer other than a hindered amine radical scavenger, a scorch inhibitor, an antioxidant, etc., as long as the physical properties are not impaired. An agent may be contained.

  If the thickness of the resin layers 1b and 1b that are the outermost layers on both sides of the solar cell adhesive sheet is thin, the adhesive property of the solar cell adhesive sheet may be reduced. When the battery module is manufactured, bubble swelling caused by the solar cell adhesive sheet may occur between the facing surfaces of the solar cell element and the protective material. Therefore, the total of the resin layers 1b and 1b that are the outermost layers on both sides is generated. The thickness is preferably 10-40% of the total thickness of the solar cell adhesive sheet, and more preferably 15-30%.

  Next, a method for forming the solar cell adhesive sheet A will be described. The film formation of the solar cell adhesive sheet A can be performed by a multilayer extrusion apparatus in which two or more extruders are connected to one T die via one feed block, for example, three layers A multi-layer extrusion apparatus having a minute-extruder, an ethylene-based copolymer for the resin layer 1b which is the outermost layer in the two extruders of this multi-layer extrusion apparatus, an organic peroxide and a silane coupling agent, and The resin layer (intermediate layer) except for the resin layer 1b, which is the outermost layer, is supplied to the remaining one extruder while supplying a resin composition containing an additive that is added as necessary and not containing a hindered amine radical scavenger. ) Supplying a resin composition containing an ethylene copolymer for 1a, an organic peroxide and a light stabilizer, and additives such as a silane coupling agent to be added as needed, each extruder Dissolve the resin composition in Kneaded and supplied to the feed block, the outermost resin layer 1b, the resin layer (intermediate layer) 1a and the outermost resin layer 1b are laminated in this order from the T-die arranged at the tip of the feed block The film can be formed by extruding into a sheet so as to be in an integrated state, and cooling and solidifying and winding the extruded molten sheet with a cooling roll. When the outermost resin layers 1b and 1b are composed of the same resin composition, melt-kneading was performed with one extruder, and the molten resin composition extruded from the extruder was branched into two. You may form into a film by supplying a feed block above.

  The solar cell adhesive sheet A having four or more layers can be manufactured in the same manner, and a multilayer extrusion apparatus having extruders corresponding to the number of solar cell adhesive sheets is prepared. The resin composition constituting each resin layer is supplied, the resin composition is melted and kneaded in each extruder, supplied to the feed block, and the resin layer from the T die disposed at the tip of the feed block Can be formed by extruding into a sheet shape so as to be laminated and integrated in a desired order, and cooling and solidifying and winding the extruded molten sheet with a cooling roll.

  When forming the adhesive sheet for solar cells by coextrusion as described above, the resin composition melt-kneaded by each extruder is supplied to the feed block and extruded from the T-die disposed at the tip of the feed block. In the T-die, the resin compositions constituting the outermost resin layers 1b and 1b are connected and integrated at both ends in the width direction of the T-die, and the remaining portions excluding the outermost resin layers 1b and 1b. It is preferable that the resin composition constituting the resin layer is covered with the resin composition constituting the outermost resin layers 1b and 1b over the entire circumference. By adjusting in this way, the resulting solar cell adhesive sheet is the outermost resin layer 1b, and by the action of the resin layer 1b, more excellent adhesion to the protective material and solar cell element is stable over a long period of time. Can be maintained.

  In the film-forming process of the adhesive sheet A for solar cells, if the temperature at which the resin composition constituting the resin layers 1a and 1b is melted and kneaded in the extruder is high, the organic peroxide in the resin composition is decomposed. Since the crosslinking of the ethylene copolymer may proceed, the temperature is preferably 10 ° C. or more lower than the one-hour half-life temperature of the organic peroxide used. In the case of using an oxide, the temperature is preferably 10 ° C. or more lower than the one-hour half-life temperature of the lowest organic peroxide among the organic peroxides to be used.

  Moreover, you may manufacture the adhesive sheet A for solar cells by laminating | stacking and integrating the film which comprises each resin layer using general methods, such as extrusion lamination, other than the said manufacturing method.

  Further, the solar cell adhesive sheet A is preferably embossed on the surface in order to improve the deaeration in the thermocompression bonding step when the solar cell module is manufactured. In addition, as a method of embossing the surface of the adhesive sheet A for solar cells, a known method is used. For example, the adhesive sheet A for solar cells in a molten state immediately after being extruded from a T die is embossed on the surface. The embossing roll on which the pattern is applied and the rubber roll arranged opposite to the embossing roll are supplied, and the embossing roll is pressed against the molten sheet to emboss the surface of the adhesive sheet A for solar cells. The method of giving is mentioned. The once produced solar cell adhesive sheet A may be heated again to a molten state and embossed as described above.

  And as a method of manufacturing a solar cell module using the adhesive sheet A for solar cells of the present invention, as shown in FIG. 2, a glass plate is disposed on the upper surface of the solar cell element 2 via the adhesive sheet A for solar cells. A laminated body in which a transparent protective material 3 is laminated and a back surface protective material 4 is laminated on the lower surface of the solar cell element 2 via a solar cell adhesive sheet A, and this laminated body is thermocompression bonded under reduced pressure. To do. Examples of the solar cell element 2 include a solar cell element having a structure using a single crystal or polycrystalline wafer, and a solar cell element in which silicon, a compound semiconductor, or the like is laminated and integrated into a thin film on a substrate. It is done.

  Then, the solar cell adhesive sheets A and A laminated on the upper and lower surfaces of the solar cell element 2 are melted, filling the gap between the solar cell elements 2 and 2 and sealing the solar cell element with the solar cell adhesive sheets A and A. Stopped. In addition, each resin layer of the adhesive sheet for solar cells is crosslinked with an organic peroxide to impart heat resistance. Further, a transparent protective material 3 is laminated and integrated on the upper surface of the solar cell element 2 via a solar cell adhesive sheet A, and the back surface protection is provided on the lower surface of the solar cell element 2 via a solar cell adhesive sheet A. The solar cell module B can be obtained by stacking and integrating the materials 4 (see FIG. 2).

  The adhesive sheet for solar cells of the present invention does not contain a hindered amine radical scavenger in the resin layers 1b and 1b that are the outermost layers on both sides, and the silane contained in the resin layers 1b and 1b that are the outermost layers on both sides. The coupling agent exhibits its action stably for a long period of time without being decomposed. Therefore, the solar cell element 2 is stably sealed by the solar cell adhesive sheets A and A for a long period of time. The Furthermore, the adhesive sheet for solar cells does not contain a hindered amine radical scavenger in the resin layers 1b and 1b which are the outermost layers on both sides, and the silane coupling agent stably maintains its action over a long period of time. The solar cell element 2, the transparent protective material 3 and the back surface protective material 4 stably exhibit excellent adhesion over a long period of time. The transparent protective material 3 and the back surface protective material 4 are the solar cell adhesive sheet A. , A is laminated and integrated on both surfaces of the solar cell element 2 stably and firmly over a long period of time.

  In the above description, the solar cell module B having a structure in which the solar cell elements are sealed and integrated from the upper and lower surfaces using the solar cell adhesive sheet has been described, but the solar cell adhesive sheet A of the present invention is described below. It can also be used for the solar cell module B having a structure.

  A solar battery cell 6 made of silicon, a compound semiconductor, or the like is laminated and integrated in a thin film shape on a transparent substrate 5, and a solar battery adhesive sheet A is laminated on the solar battery cell 6, and solar battery adhesion is performed. The laminated body which laminated | stacked the back surface protection material 4 on the sheet | seat A was produced, and this laminated body was heat-pressed under pressure reduction, the transparent substrate 5, the photovoltaic cell 6, the adhesive sheet A for solar cells, and the back surface protection material 4 Can be obtained (see FIG. 3). The solar battery cell 6 is sealed and integrated by the transparent substrate 5 and the solar battery adhesive sheet A.

  In any solar cell module B, the solar cell adhesive sheet A is integrated on the lower surface of the solar cell element, but becomes the outermost layer of the solar cell adhesive sheet A facing the solar cell element and the protective material. The resin layer 1b contains a silane coupling agent and no hindered amine radical scavenger, and the solar cell adhesive sheet A, the solar cell element, and the protective material are firmly integrated. The element is stably sealed over a long period of time by the solar cell adhesive sheet and the protective material.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Examples 1-3, Comparative Examples 1-4)
Prepare a three-layer coextrusion device in which three extruders are connected to one T-die via one feed block, and two of these extruders are resin layers 1b and 1b that are the outermost layers on both sides. The remaining one machine was used for the resin layer 1a excluding the resin layer serving as the outermost layer, that is, for the intermediate layer.

  Each of the outermost resin layers 1b and 1b on both sides and an extruder for the resin layer (intermediate layer) 1a excluding the outermost resin layer is an ethylene-vinyl acetate copolymer (vinyl acetate). Content: 28% by weight, melt flow rate: 20 g / 10 min) 100 parts by weight, a predetermined amount of 3-glycidoxypropyltrimethoxysilane or 3-aminopropyltrimethoxysilane shown in Table 1 as a silane coupling agent A predetermined amount of bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate or poly [{6- (1,1,3,3-tetramethyl) shown in Table 1 as a hindered amine-based radical scavenger. Butyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-te Ramethyl-4-piperidyl) imino}], 0.3 parts by weight of triallyl isocyanurate, 0.5 parts by weight of dicumyl peroxide as an organic peroxide, and 2- (3,5-di-t-- as an ultraviolet absorber. A resin composition containing 0.2 parts by weight of butyl-2-hydroxyphenyl) -5-chlorobenzotriazole was supplied.

  Next, the resin composition is melted and kneaded at 120 ° C. in each of the three extruders, the molten resin composition is supplied to the feed block, and one of the T dies disposed at the tip of the feed block is A resin layer 1b composed of a resin composition extruded from an extruder for the resin layer 1b as the outermost layer, a resin layer 1a composed of a resin composition extruded from an extruder for an intermediate layer, and the other outermost layer The resin layer 1b made of the resin composition extruded from the extruder for the resin layer 1b is co-extruded into a laminated and integrated state in this order, and an outermost layer is formed on both surfaces of one resin layer (intermediate layer) 1a. A solar cell adhesive sheet A having a three-layer structure in which the resin layers 1b and 1b are laminated and integrated was formed. The thickness of the solar cell adhesive sheet A was 0.5 mm. The thickness ratio of the outermost layer 1b, the intermediate layer 1a, and the outermost layer 1a in the solar cell adhesive sheet A was adjusted to be 1: 10: 1.

  After that, the molten solar cell adhesive sheet A immediately after being co-extruded from the T-die is supplied between the embossing roll and a rubber roll disposed so as to face the embossing roll. Is pressed on the molten solar cell adhesive sheet A, the surface of the solar cell adhesive sheet A is embossed to a depth of 0.3 mm, and then wound while being cooled by a cooling roll, thereby forming three layers. A solar cell adhesive sheet A having the structure was obtained.

  About the adhesive sheet A for solar cells obtained by the Example and the comparative example, adhesiveness was measured in the following way, and the result was shown in Table 1.

(Adhesiveness)
From the obtained adhesive sheet for solar cells, a plane rectangular test piece having a length of 30 mm and a width of 20 mm was cut out. By placing the test piece on a glass plate, supplying the test piece to a vacuum laminator, vacuuming the atmosphere in which the test piece is placed, and heating the test piece to 145 ° C. The test piece was brought into close contact with the glass plate at substantially the same pressure as the atmospheric pressure, and the test piece and the glass plate were bonded and integrated to prepare a test specimen.

  Immediately after preparing the test body, the 180 ° peel strength when peeling the test piece from the glass plate (hereinafter referred to as “peel strength immediately after production”) conforms to JIS Z1707 (7.5 heat seal strength (3) operation). And measured.

  A test specimen was prepared in the same manner as described above, and this specimen was allowed to stand for 10 days in an atmosphere of 23 ° C. and a relative humidity of 70%, and then 180 ° peeling when peeling the test piece from the glass plate. The strength (hereinafter referred to as “peel strength after 10 days”) was measured in accordance with JIS Z1707 (7.5 heat seal strength (3) operation).

  In addition, a test specimen was prepared in the same manner as described above, and after leaving the test specimen for 30 days in an atmosphere of 23 ° C. and 70% relative humidity, 180 when the specimen was peeled from the glass plate. The peel strength (hereinafter referred to as “peel strength after 30 days”) was measured in accordance with JIS Z1707 (7.5 heat seal strength (3) operation).

  Further, a test specimen was prepared in the same manner as described above, and the specimen was left for 60 days in an atmosphere of 23 ° C. and a relative humidity of 70 ° C., and then 180 when peeling the test piece from the glass plate. The peel strength (hereinafter referred to as “peel strength after 60 days”) was measured in accordance with JIS Z1707 (7.5 heat seal strength (3) operation).

  Then, 10 days later peel strength, 30 days later peel strength and 60 days later peel strength were each divided by the peel strength immediately after production and multiplied by 100, and this retention rate was evaluated based on the following criteria.

○: The maintenance ratio was 90% or more.
Δ: The maintenance ratio was 80% or more and less than 90%.
X: The maintenance ratio was less than 80%.

1a Resin layer excluding the outermost resin layer (intermediate layer)
1b Resin layer 2 as outermost layer Solar cell element 3 Transparent protective material 4 Back surface protective material 5 Transparent substrate 6 Solar cell A Adhesive sheet B for solar cell Solar cell module

Claims (2)

An adhesive sheet for solar cells in which three or more resin layers containing an ethylene copolymer and an organic peroxide are laminated and integrated, and at least one of the resin layers excluding the outermost resin layer The resin layer contains a light stabilizer, and the resin layer which is the outermost layer on both sides contains 0.05 to 3 parts by weight of a silane coupling agent with respect to 100 parts by weight of the ethylene copolymer, and is a hindered amine. An adhesive sheet for solar cells, which does not contain a system radical scavenger. A resin composition containing an ethylene copolymer and an organic peroxide is supplied to each of a plurality of extruders, melted and kneaded, and the resin composition is supplied to a T die to which all the extruders are connected. A manufacturing method for producing an adhesive sheet for a solar cell in which three or more resin layers made of the resin composition are laminated and integrated by co-extrusion, and the resin composition is supplied to the extruder. At least one resin composition contains a light stabilizer, and this resin composition constitutes at least one of the remaining resin layers excluding the outermost resin layer and is the outermost resin layer. The resin composition constituting the layer is characterized by containing 0.05 to 3 parts by weight of a silane coupling agent and not containing a hindered amine radical scavenger with respect to 100 parts by weight of the ethylene copolymer. The production method of the adhesive sheet for a solar cell.

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