JP2010027815A - Rear surface protecting sheet for solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rear surface protecting sheet for a solar cell module which has flexibility and such characteristics as thermal resistance and humidity resistance and does not require any addition of bases even when absorption characteristics and reflection characteristics of sunlight are provided. <P>SOLUTION: The rear surface protecting sheet 1 for a solar cell has a structure formed by pasting a heat-resistant base 13 to which heat-resistance treatment is carried out and a humidity-resistance base 15 to which humidity resistance is given with an adhesive 14. Both of the heat resistance and the humidity resistance can be provided by pasting the heat-resistant base 13 and the humidity-resistance base 15. In addition, flexibility is provided by using the adhesive 14 and exfoliation or the like of the bases does not occur in bending. Efficiency of sunlight utilization and designability can be improved by adding coloring agent to the adhesive 14. Moreover, deterioration by ultraviolet irradiation can be prevented by adding ultraviolet absorber to the adhesive 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a back surface protection sheet for a solar cell module having both heat resistance and moisture resistance and flexibility.

  In recent years, in order to reduce carbon dioxide derived from petroleum fuel, energy using natural power such as sunlight and wind power has attracted attention. In particular, the demand for solar cell modules is growing as public opinion on environmental issues increases.

  In general, a solar cell module has a structure in which glass or a film, a sealing material mainly composed of ethylene-vinyl acetate, a solar cell element, and a back surface protection sheet are laminated in order from the light-receiving surface side mainly receiving sunlight. Have Then, in a state where these members are laminated, the four corners are fixed with a frame such as aluminum after being heated and pressure-bonded under vacuum.

  Since the solar cell module is installed outdoors, it is exposed to changes in the weather such as sunlight, cold and warm, and wind and rain for a long period of time. Therefore, the back surface protection sheet constituting the solar cell module is also required to have heat resistance, light resistance, moisture resistance and the like, as with other constituent materials. As the base material used for the backside protection sheet, materials that have been appropriately devised in various ways such as acrylic, polyolefin, polyvinyl chloride, fluorine, and polyester are used to withstand long-term outdoor exposure. Is done. And if necessary, a black colored substrate for the purpose of absorbing sunlight and design, and a white colored substrate for the purpose of reflecting and design of sunlight, etc. are laminated, The back surface protection sheet for solar cell modules is created by bonding together with an adhesive.

In recent years, in order to install and use a solar cell module on a curved surface, attempts have been made to make the solar cell module flexible. In order to give the solar cell module flexibility, the back surface protection sheet to be used is also required to have flexibility. However, in the conventional configuration in which the substrates are bonded together with an adhesive, the adhesive is highly cohesive, and the adhesive is cracked at the time of bending, causing a phenomenon that the substrate is peeled off. Under such circumstances, a solar cell backsheet having a configuration in which a plurality of base materials are bonded together using a pressure-sensitive adhesive having lower cohesiveness than an adhesive has been proposed (see, for example, Patent Document 1).
JP 2005-197553 A

  However, the above-described solar cell backsheet has a configuration in which a moisture-resistant base material and a transparent resin film are bonded together with an adhesive, and there is a problem that the heat resistance is fragile. In addition, in order to provide solar cell backsheets with solar absorption and reflection characteristics, a black colored base material or a white colored base material must be separately laminated, which increases the cost of the sheet. There is a point.

  The present invention has been made to solve the above-described problems, has flexibility, has both heat resistance and moisture resistance, and further has sunlight absorption and reflection characteristics. Even if it is a case, it aims at providing the back surface protection sheet for solar cell modules which does not require the addition of a base material.

  In order to solve the above-mentioned problems, the back protective sheet for a solar cell module of the invention according to claim 1 includes a heat-resistant substrate which is a substrate subjected to heat treatment, and a substrate to which moisture resistance is imparted. It is characterized by having a structure in which a moisture-resistant base material is laminated, and the heat-resistant base material and the moisture-resistant base material are bonded together with an adhesive.

  Moreover, the back surface protection sheet for solar cell modules of the invention which concerns on Claim 2 is characterized by the above-mentioned adhesive containing the coloring agent in addition to the structure of invention of Claim 1.

  Moreover, in addition to the structure of the invention of Claim 1 or 2, the back surface protection sheet for solar cell modules of the invention concerning Claim 3 contains the ultraviolet absorber in the said adhesive. And

  Moreover, in addition to the structure of the invention according to any one of claims 1 to 3, the back protective sheet for a solar cell module according to the invention according to claim 4 has a coating thickness of 10 μm or more and 30 μm after drying of the pressure-sensitive adhesive. It is characterized by the following.

  The back surface protection sheet for a solar cell module of the invention according to claim 1 has a structure in which a heat-resistant base material subjected to a heat treatment and a moisture-resistant base material provided with moisture resistance are laminated. It is possible to provide the solar cell module back surface protective sheet with both properties and moisture resistance. Moreover, even when it is a case where a sheet | seat is curved by sticking both base materials together, even if it is a case where a sheet | seat is curved, it follows a base material favorably. Thereby, it becomes possible to give flexibility to the back surface protection sheet for solar cell modules.

  Moreover, the back surface protection sheet for solar cell modules of the invention which concerns on Claim 2 makes a solar cell favorably irradiate sunlight by making an adhesive contain a coloring agent and coloring a back surface protection sheet for solar cell modules. Use in modules. Here, since it is not necessary to separately laminate the colored base material, in addition to the effect of the invention according to claim 1, it is possible to suppress the material cost of the back surface protective sheet for solar cell module. Moreover, since it becomes possible to reduce the manufacturing process at the time of manufacture of the back surface protection sheet for solar cell modules, it becomes possible to suppress manufacturing cost. Further, the sheet can be thinned, and application to a thin film type solar cell module is possible.

  Moreover, since the back surface protection sheet for solar cell modules of the invention which concerns on Claim 3 can make an adhesive absorb an ultraviolet-ray in addition to the effect of the invention of Claim 1 or 2, weather resistance and Light resistance is improved, and it is possible to prevent deterioration of the solar cell module.

  Moreover, in addition to the effect of the invention in any one of Claims 1 thru | or 3, the back surface protection sheet for solar cell modules of the invention which concerns on Claim 4 is an adhesive, when a base material is laminated | stacked and bonded together. Can be prevented from protruding.

  Hereinafter, the back surface protection sheet 1 for solar cell modules that embodies the present invention (hereinafter abbreviated as “back surface protection sheet 1”) will be described with reference to the drawings. These drawings are used for explaining the technical features that can be adopted by the present invention, and the contents described are not intended to be limited only to them unless otherwise specified. It is merely an illustrative example.

  With reference to FIG. 1, the structure of the solar cell module 100 containing the back surface protection sheet 1 is demonstrated. FIG. 1 is a schematic diagram showing a cross-sectional structure of the solar cell module 100. 1 is defined as the upper side of the solar cell module 100.

  As shown in FIG. 1, the solar cell module 100 includes a film 10, a sealing material 11, a solar cell element 12, and a back surface protection sheet 1. And these, the sealing material 11 is coated on the upper side of the back surface protection sheet 1, the solar cell element 12 is disposed so that the periphery is covered with the coated sealing material 11, and the film 10 is from above. The sealing material 11 and the solar cell element 12 are covered.

  Moreover, the back surface protection sheet 1 is a pressure-sensitive adhesive 14 in a state in which a heat-resistant substrate 13 that is a heat-treated substrate and a moisture-resistant substrate 15 that is given moisture resistance are mixed with a colorant. It has the structure bonded together. And these are in the state where adhesive 14 was applied to the upper side of heat-resistant substrate 13, and moisture-resistant substrate 15 was pasted on the upper side of adhesive 14. The sealing material 11 and the solar cell element 12 are in contact with the heat resistant substrate 13 on the upper surface of the heat resistant substrate 13.

  The film 10 is covered with the solar cell element 12 in order to prevent the solar cell element 12 from being exposed to the outside and protect the solar cell element 12. Moreover, the sealing material 11 is provided in order to suppress the influence of the friction stress, temperature, and humidity with respect to the solar cell element 12, for example, the material which has ethylene-vinyl acetate as a main component can be used. Moreover, the solar cell element 12 is an element which can generate a photovoltaic power by irradiating sunlight. The solar cell element 12 in which the back surface protective sheet 1 of the present embodiment can be used is not particularly limited, and a conventionally known solar cell element can be used. For example, silicon-based, compound-based (GaAs, etc.), organic System solar cell elements.

  The back surface protection sheet 1 is provided to support the solar cell element 12 from the back surface and to protect the solar cell element 12. As the heat-resistant substrate 13 and the moisture-resistant substrate 15 constituting the back surface protective sheet 1, any of acrylic, polyolefin, polyvinyl chloride, fluorine, and polyester materials can be used as the substrate. However, inexpensive and highly versatile polyesters are preferably used. Among them, biaxially stretched polyethylene terephthalate having high tensile strength and tear strength is more preferably used.

  The heat resistant substrate 13 is heat resistant by annealing. In addition, in order to prevent the malfunction which shrink | contracts with the heat | fever added in the manufacturing process of the solar cell module 100, as the heat resistant base material 13, the biaxially-stretched polyethylene terephthalate which set heat shrinkage rate to 1% or less is preferable. used. Among them, biaxially stretched polyethylene terephthalate having a heat shrinkage rate set to 0.5% or less is preferably used. This is because when the thermal shrinkage rate is 1%, more preferably 0.5% or less, it is possible to prevent a shift due to shrinkage when heating and pressure bonding under vacuum.

  The moisture resistant substrate 15 is provided with moisture resistance by forming a thin film of aluminum oxide or silicon oxide inorganic oxide on the surface. As a thin film forming method, a sputtering method, an ion plating method, a plasma vapor deposition method (CVD), or the like can be used in addition to a normal vacuum deposition method.

  In consideration of being exposed to the outdoors for a long time, the pressure-sensitive adhesive 14 is preferably one containing an acrylic polymer having a weather resistance and a crosslinking agent. As the acrylic polymer, a copolymer using acrylic acid ester, methacrylic acid ester and a combination thereof as a monomer is used. Specifically, copolymers using methyl acrylate, ethyl acrylate, N-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl acrylate and combinations thereof as monomers Is used. This is because the cohesive effect of the pressure-sensitive adhesive can be easily obtained by adjusting the molecular weight by copolymerization. Among these, n-butyl acrylate and 2-ethylhexyl acrylate, which are particularly excellent in adhesive performance at low temperatures, are preferably used as monomers.

  Moreover, it is preferable that the adhesive 14 is a copolymer of the monomer which becomes the above-mentioned main component, and the monomer which has a functional group which can react with a crosslinking agent. As the monomer having a functional group capable of reacting with a crosslinking agent, hydroxyalkyl ester of acrylic acid, hydroxyalkyl ester of methacrylic acid, unsaturated carboxylic acid, and combinations thereof are preferably used. Specifically, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 4-hydroxybutyl acrylate are preferably used as the hydroxyalkyl ester of acrylic acid, and 2-hydroxyethyl methacrylate as the hydroxyalkyl ester of methacrylic acid. 2-hydroxypropyl methacrylate and 4-hydroxybutyl methacrylate are preferably used, and acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid are preferably used as the unsaturated carboxylic acid.

  In particular, the use of one or more of 2-hydroxyethyl acrylate, acrylic acid, and methacrylic acid is preferable because the aggregation effect by polymerization with n-butyl acrylate and 2-ethylhexyl acrylate is increased. When the acrylic polymer is a copolymer, the main component is 90 to 99.5 parts by weight as a monomer unit of the copolymer, and the monomer having a functional group that reacts with the crosslinking agent takes into account the balance between cohesiveness and adhesiveness. Then, it is preferable that it is 0.5-10 weight part.

  The crosslinking agent used is an isocyanate compound such as triresin isocyanate, hexamethylene diisocyanate, trimethylolpropane tolylene diisocyanate, diphenylmethane triisocyanate, or an epichlorohydrin type epoxy that shows a good reaction with the hydroxyl group and carboxyl group in the functional group monomer. Resins, epoxy compounds such as ethylene glycol glycidyl ether, polyethylene diglycidyl ether, glycerin diglycidyl ether, amine compounds such as hexamethylenediamine, triethyldiamine, polyethyleneimine, aluminum, iron, copper, zinc, tin, titanium, nickel Metal chelate compounds coordinated to polyvalent metal acetylacetone and ethyl acetoacetate such as N, N′-diphenylmethane-4,4′-bis (1 1 or 2 or more kinds of aziridine compounds such as aziridian carboxylate), N, N′-toluene-2,4-bis (1-aziridinecarboxide), tri-1-aziridinylphosphine oxide Can be used as a mixture.

  A predetermined pressure-sensitive adhesive performance can be obtained by cross-linking the pressure-sensitive adhesive polymer having an acrylic polymer as a main component with a crosslinking agent.

  The addition amount of the crosslinking agent is preferably 0.05 to 15 parts by weight in terms of solid content with respect to 100 parts by weight of the pressure-sensitive adhesive polymer. When the amount is less than 0.05 parts by weight, the pressure-sensitive adhesive is soft, and the pressure applied to the pressure-sensitive adhesive is likely to occur due to heat applied when the solar cell module 100 is laminated. In addition, due to the softness, workability is greatly deteriorated, such as adhesion of adhesive to the blade during slitting. On the other hand, if it exceeds 15 parts by weight, the interlayer will float and peel due to insufficient adhesive force, making it difficult to laminate the substrates.

  Further, as the colorant blended in the pressure-sensitive adhesive 14, a known colorant such as a pigment such as an organic pigment or an inorganic pigment or a dye can be suitably used. You may mix and use a pigment and dye as needed. Of these, black pigments are preferred from the viewpoints of weather resistance and heat resistance. Specific examples of organic pigments include azo pigments, anthraquinone pigments, indigo pigments, thioindigo pigments, perylene / perinone pigments, quinacridone pigments, dioxazine pigments, quinophthalone pigments, isoindolinone pigments, pyrrole pigments, phthalocyanine pigments, aniline black Examples thereof include pigments and carbon black pigments. Examples of inorganic pigments include metal oxide pigments such as titanium oxide pigments and iron oxide pigments, chromate pigments, sulfide pigments, silicate pigments, carbonate pigments, and ferrocyan compounds. Is mentioned. It is desirable to use one or more selected from the above-mentioned organic pigments and inorganic pigments and having an average particle diameter of the pigment of 0.03 to 0.30 μm from the viewpoint of uniformly dispersing in the pressure-sensitive adhesive layer. .

As the dye, one or more selected from basic dyes, acid dyes, direct dyes, acid mordant dyes, or mordant dyes can be used. There are various types of dyes, and chemical structures include azo dyes, anthraquinone dyes, triphenylmethane dyes, pyrazolone dyes, stilbene dyes, diphenylmethane dyes, azomethine dyes, xanthene dyes, alizarin dyes, acridine dyes, quinone imines. Examples include dyes (azine dyes, oxazine dyes, thiazine dyes), cyanine dyes, quinoline dyes, thiazole dyes, methine dyes, and nitro dyes. The colorant blended in the pressure-sensitive adhesive 14 is preferably 45 parts by weight or less in terms of solid content with respect to 100 parts by weight of the acrylic polymer. This is because when the amount exceeds 45 parts by weight, a problem that the adhesive performance is difficult to be exhibited occurs.

  The acrylic polymer solution used as the pressure-sensitive adhesive 14 in the present invention has a known crosslinking accelerator, a tackifier, a plasticizer, a filler, and the like, as long as the moisture resistance, pressure-sensitive adhesive properties, etc. are not impaired. Various additives such as an agent, an antioxidant, a flame retardant, an antistatic agent, and a light stabilizer can be appropriately added.

  The adhesive 14 can be mixed with an ultraviolet absorber. UV absorber is compatible with acrylic adhesive and 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-butylphenyl) is less likely to bleed out after compounding Benzotriazole, 2- (2-hydroxy5-octylphenyl) benzotriazole, 2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chlorobenzotriazole, 2- (3,5-di Benzotriazoles such as -t-amyl-2-hydroxyphenyl) benzotriazole, 2- [4,6bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- ( Octyloxy) phenol, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) phenol, etc. Triazine-based, P-tert-butylphenyl salicylate, among salicylate ultraviolet absorbers such as phenyl salicylate, it is possible to use a mixture of one kind or two kinds or more.

  Among these, a benzotriazole ultraviolet absorber having a molecular weight of 235 to 418 is preferably used. If the molecular weight is less than 235, a remarkable effect is not seen in the ultraviolet absorption performance, and if it exceeds 418, the dispersion stability of the colorant is deteriorated and coating unevenness occurs.

  The blending of the above benzotriazole-based UV absorber is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 7 parts by weight, in terms of solid content, with respect to 100 parts by weight of the acrylic polymer. More preferably. If the amount is less than 0.1 parts by weight, satisfactory ultraviolet absorption performance cannot be obtained. If the amount is 10 parts by weight or more, in addition to the difference in ultraviolet absorption performance to be obtained, adhesive performance (particularly, tackiness, etc.) is extremely reduced. Because.

  A method for bonding the heat resistant substrate 13 and the moisture resistant substrate 15 will be described. After the pressure-sensitive adhesive 14 is applied to the heat-resistant substrate 13 and dried, the moisture-resistant substrate 15 is bonded. The method for applying the pressure-sensitive adhesive 14 is not particularly limited, and a conventionally known coating method can be used. For example, a gravure printing method, a spray method, a roll coater method, and a die coater method can be used.

  About the application | coating thickness of the adhesive 14, it is preferable that they are 10 micrometers-30 micrometers. This is because if the thickness is less than 10 μm, peeling between the substrates tends to occur due to insufficient adhesive force. On the other hand, if the thickness exceeds 30 μm, a problem that the adhesive 14 is likely to protrude during the processing of the back surface protection sheet 1 is likely to occur.

As described above, the back protective sheet 1 having heat resistance and moisture resistance can be produced by stacking the heat resistant substrate 13 and the moisture resistant substrate 15. Moreover, by bonding both base materials together with the pressure-sensitive adhesive 14, it becomes possible to create a flexible back surface protection sheet 1 that does not cause peeling of the base material even during bending. Moreover, it becomes possible to implement | achieve the improvement in the efficiency of sunlight utilization, and the improvement in design property by making the adhesive 14 contain a coloring agent. Furthermore, it becomes possible to make the back surface protection sheet 1 with little deterioration by ultraviolet irradiation by containing the ultraviolet absorber in the adhesive 14.
<Example>

The Example of the back surface protection sheet 1 of this invention and the result of the evaluation using the created back surface protection sheet 1 are demonstrated. Hereinafter, “1. Evaluation sample details”, “2. Evaluation method”, and “3. Evaluation result” will be described in this order. In addition, this invention is not limited to a following example.
1. Evaluation sample details

  A pressure-sensitive adhesive 14 in which a colorant and an ultraviolet absorber were blended was generated, and the heat-resistant substrate 13 and the moisture-resistant substrate 15 were bonded together with the generated pressure-sensitive adhesive 14 to prepare a sample.

  As the adhesive 14, an adhesive mainly composed of an acrylic polymer was used. This pressure-sensitive adhesive is composed of an acrylic polymer (a copolymer of 75 parts by weight of butyl acrylate, 20 parts by weight of methyl acrylate, and 5 parts by weight of acrylic acid, out of a total weight of 100 parts by weight of monomer components) of 60 parts by weight of solvent It was dissolved in (a solvent obtained by mixing 20 parts by weight of toluene, 30 parts by weight of ethyl acetate, and 10 parts by weight of MEK) to obtain an acrylic polymer having a solid content of 40% by weight. (Hereinafter referred to as “main agent”) Further, as the crosslinking agent, 2,4 (2,6) -tolylene diisocyanate dissolved in ethyl acetate and adjusted to a solid content of 45% by weight was used. Moreover, as a coloring agent, what mixed iron oxide black 20 weight part and organic black 20 weight part% with respect to the main ingredient was used. Moreover, the benzotriazole type ultraviolet absorber was used as a ultraviolet absorber. And after mix | blending these, it was set as the state left still for 2 hours, and was used as the adhesive 14.

  As the heat-resistant substrate 13, “Lumirror (registered trademark) X10S” manufactured by Toray Industries, Inc. was used. Further, as the moisture-resistant substrate 15, a silica vapor deposited polyethylene terephthalate film “T-SR” manufactured by Oike Pack Material Co., Ltd. was used.

  When the heat-resistant substrate 13 and the moisture-resistant substrate 15 were bonded together, the pressure-sensitive adhesive 14 was applied to the heat-resistant substrate 13, and the moisture-resistant substrate 15 was bonded thereon.

  The pressure-sensitive adhesive 14 blended at a ratio of 0.7 part by weight of the crosslinking agent with respect to 100 parts by weight of the main agent was produced. And the coloring agent was mix | blended in the ratio of 15 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 1”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.05 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 30 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 2”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 15 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 30 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 3”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 30 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 4”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 30 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 30 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 5”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 45 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 6”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 45 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 30 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 7”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 45 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 10 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 8”.

  Moreover, the adhesive 14 mix | blended in the ratio of 15.0 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 30 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 9”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 10 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be 10 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 10”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 10 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 35 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 11”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 15 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 5 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 12”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 15 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 35 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 13”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 45 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 5 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 14”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 45 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 35 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 15”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 50 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 5 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 16”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 50 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 35 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 17”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 30 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 0.05 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 18”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 30 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 12 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 19”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.7 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 30 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 0.1 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 20”.

  Moreover, the adhesive 14 mix | blended in the ratio of 16.0 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 30 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 21”.

  Moreover, the adhesive 14 mix | blended in the ratio of 0.03 weight part of crosslinking agents with respect to 100 weight part of main agents was produced | generated. And the coloring agent was mix | blended in the ratio of 30 weight part with respect to the produced | generated adhesive 14, and the ultraviolet absorber was mix | blended in the ratio of 5 weight part. And the produced | generated adhesive 14 was applied to the heat resistant base material 13 so that the thickness after drying might be set to 20 micrometers, and the moisture resistant base material 15 was affixed on it. The back surface protection sheet created under these conditions is referred to as “sheet 22”.

  A back surface protective sheet 1 having a configuration in which a polyurethane-based adhesive was used in place of the pressure-sensitive adhesive 14 and a black base material was separately laminated was prepared. After blending a general-purpose adhesive, it was allowed to stand for 2 hours. In this state, it was applied to the heat-resistant substrate 13 so that the thickness after drying was 20 μm, and the moisture-resistant substrate 15 was bonded thereon. . Further, the above-mentioned adhesive layer was applied to Toray-made black base material 5 “Lumirror X30” (hereinafter referred to as “black base material”) so as to have a thickness of 20 μm after drying, and was bonded to the heat-resistant base material 13. The above-mentioned black substrate was bonded to the opposite side of the surface in contact with the adhesive in the moisture-resistant substrate 15 in the state. The back surface protection sheet created under these conditions is referred to as “sheet 23”.

  A back protective sheet 1 using a polyurethane adhesive instead of the adhesive 14 was prepared. After blending a general-purpose adhesive, it was allowed to stand for 2 hours, and in this state, it was applied to the heat-resistant substrate 13 so that the thickness after drying was 20 μm, and the moisture-resistant substrate 15 was stuck thereon. . The back surface protection sheet created under these conditions is referred to as “sheet 24”.

２．評価方法 Details regarding the above sheets are summarized in Table 1.

2. Evaluation methods

For the sheets 1 to 24 prepared as described above, 1) evaluation of adhesive strength of the adhesive 14, 2) evaluation of UV resistance, 3) processing, coating suitability evaluation, and 4) evaluation of flexibility were performed.
1) Evaluation of adhesive strength of adhesive 14

For the evaluation of the adhesive strength of the adhesive 14, soda lime glass was bonded to the heat-resistant substrate 13 side of the sheets 1 to 22 prepared as described above, and Autograph “AGS-500NG” manufactured by Shimadzu Corporation. The value when the moisture-resistant substrate 15 was pulled up under the conditions of a pulling angle of 180 ° and a pulling speed of 300 mm / min was converted to a width of 25 mm to obtain an adhesive force. And when the adhesive force obtained was 10 N (/ 25 mm) or more, it was judged that it has favorable adhesiveness as the back surface protection sheet 1.
2) UV resistance evaluation

For the evaluation of ultraviolet characteristics, the sheets 1 to 22 prepared as described above were irradiated with ultraviolet rays (irradiation conditions: frame-side xenon irradiation, illuminance: 70 W / m ² , temperature / humidity conditions: BPT, 65 ° C., 50%) was irradiated for 500 hours, and the deteriorated state was visually evaluated in a state where the back surface protective sheet 1 after irradiation was extended by hand.
3) Processing and coating suitability evaluation

For the processing suitability evaluation, when the sheet 1 to the sheet 22 (200 m) created as described above are wound and slitted, it is determined whether or not the adhesive 14 adheres to the slit blade. Executed by. Moreover, about coating appropriateness evaluation, in the process which produces the sheet | seat 1-the sheet | seat 22, the partial color nonuniformity of the coloring agent contained in the adhesive 14 in the application to the heat resistant base material 13 of the adhesive 14 is carried out. It was visually determined whether or not this occurred.
4) Evaluation of flexibility

For flexibility evaluation, sheets 1 to 24 prepared as described above were cut to a size of 50 mm × 250 mm, and the measured numerical values were bent using a Clark stiffness tester manufactured by Kumagai Riki Kogyo Co., Ltd. Assessed as sex.
3. Evaluation results

１）粘着剤１４の粘着力評価 The measurement results for Sheet 1 to Sheet 24 are shown in Table 2.

1) Evaluation of adhesive strength of adhesive 14

  As a result of evaluating the adhesive strength of the adhesive 14, as shown in Table 2, the adhesive strength of the sheets 1 to 10 is 10 N or more, and the adhesive 14 in these sheets shows good adhesiveness. It was.

  On the other hand, about the sheet | seat 11, the sheet | seat 13, the sheet | seat 15, and the sheet | seat 17, it turned out that cohesive failure generate | occur | produces during evaluation and does not show favorable adhesiveness. It is surmised that this is because the coating thickness of the adhesive 14 is too thick (35 μm or more) (see Table 1). In addition, in the case where the coating thickness of the adhesive 14 is 30 μm, it shows good adhesiveness (sheet 3: 21.1 N, sheet 5: 18.5 N, sheet 7: 13.7 N), and cohesive failure Since it did not generate | occur | produce, it became clear that it is preferable that the coating thickness of the adhesive 14 is 30 micrometers or less.

  In addition, the sheet 12, the sheet 14, and the sheet 16 also had an adhesive force of less than 10 N, and it was found that good adhesiveness was not exhibited. It is surmised that this is because the coating thickness of the adhesive 14 is too thin (5 μm or less) (see Table 1). In addition, when the coating thickness of the adhesive 14 is 10 micrometers, since the favorable adhesiveness is shown (sheet | seat 10: 11.6N), it is preferable that the coating thickness of the adhesive 14 is 10 micrometers or more. It became clear.

  Moreover, also about the sheet | seat 19 and the sheet | seat 21, it turned out that adhesive force becomes less than 10 N and does not show favorable adhesiveness. It is inferred that this is because there is too much UV absorber or cross-linking agent contained in the adhesive 14 (UV absorber: 12 parts by weight (sheet 19), cross-linking agent: 16 parts by weight (sheet 21)). (See Table 1). In addition, in the case where the content of the ultraviolet absorber is 10 parts by weight, since it shows good adhesiveness (sheet 8: 10.4 N), the content of the ultraviolet absorber contained in the adhesive 14 is 10 It became clear that it is preferable that it is below the weight part. In addition, when the content of the cross-linking agent is 15 parts by weight, since it shows good adhesiveness (sheet 9: 10.1 N), the content of the cross-linking agent contained in the pressure-sensitive adhesive 14 is 15 parts by weight. It has become clear that the following is preferable.

In addition, from the result of Display 2, the adhesive strength of the adhesive 14 tends to decrease with an increase in the content of the crosslinking agent to be included. When the content exceeds 15 parts by weight, it is difficult to stack the base materials. It was found that the sex decreased.
2) UV resistance evaluation

  As a result of the evaluation against ultraviolet characteristics, as shown in Table 2, the sheets 1 to 17 and the sheets 19 to 22 were not found to be deteriorated by irradiation with ultraviolet rays. In these sheets, the ultraviolet absorption contained in the adhesive 14 was not found. It was found that the agent can sufficiently absorb ultraviolet rays and prevent the base material and the like from being deteriorated.

Moreover, about the sheet | seat 18, deterioration was observed in the sheet | seat by ultraviolet irradiation, and it turned out that a favorable ultraviolet-ray resistant characteristic is not shown. It is surmised that this is because the UV absorber contained in the adhesive 14 is too small (0.05 parts by weight) (see Table 1). In addition, when the content of the ultraviolet absorber is 0.1 part by weight, the ultraviolet absorber content with respect to the adhesive 14 is 0. It became clear that the amount is preferably 1 part by weight or more.
3) Processing and coating suitability evaluation

  As a result of the processing suitability evaluation, as shown in Table 2, the adhesive 14 does not adhere to the slit blade even during slit processing for the sheets 1 to 10, the sheet 12, the sheet 14, the sheet 16, and the sheets 18 to 21. It was found that good processing suitability was exhibited.

  On the other hand, regarding the sheet 11, the sheet 13, the sheet 15, and the sheet 17, it was found that the adhesive 14 adhered to the slit blade at the time of slit processing, and did not show good processing suitability. It is surmised that this is because the coating thickness of the adhesive 14 is too thick (35 μm or more) (see Table 1). In addition, in the case where the coating thickness of the adhesive 14 is 30 μm, it indicates good processing suitability (sheet 3, sheet 5, sheet 7: good), and therefore the coating thickness of the adhesive 14 is 30 μm or less. It turned out to be preferable.

  Moreover, also about the sheet | seat 22, it turned out that the adhesive 14 adheres very much to a slit blade at the time of a slit process, and does not show a favorable process appropriate characteristic. It is surmised that this is because the amount of the crosslinking agent contained in the pressure-sensitive adhesive 14 is too small (0.03 parts by weight) (see Table 1). In addition, in the case where the content of the crosslinking agent is 0.05 parts by weight, since it indicates good processing suitability (sheet 2: good), the content of the crosslinking agent contained in the pressure-sensitive adhesive 14 is 0.05. It became clear that it is preferable to be at least parts by weight.

  Moreover, as shown in Table 2, as a result of the coating suitability evaluation, the sheet 1 to the sheet 15 and the sheet 18 to the sheet 22 have good coating suitability without causing partial color unevenness of the colorant. I found out.

On the other hand, with respect to the sheet 16 and the sheet 17, it was found that the colorant in the pressure-sensitive adhesive 14 was settled and color unevenness was generated, and good coating appropriate characteristics were not exhibited. It is surmised that this is because the colorant contained in the pressure-sensitive adhesive 14 is too much (50 parts by weight) (see Table 1). In addition, when content of a coloring agent is 45 weight part or less, since it has shown the favorable coating appropriate characteristic (Sheet 6-Sheet 8, Sheet 14, Sheet 15: Good), it contains in adhesive 14 It was revealed that the content of the colorant to be used is preferably 45 parts by weight or less.
4) Evaluation of flexibility

  About sheet 1-sheet 22 which used adhesive 14 in order to paste together heat resistant substrate 13 and moisture resistant substrate 15, it turned out that flexibility becomes 66 or more and shows favorable flexibility. From this result, it became clear that by using the pressure-sensitive adhesive 14, good flexibility is exhibited regardless of the coating thickness of the pressure-sensitive adhesive 14.

  On the other hand, the sheet 23 and the sheet 24, which use an adhesive to bond the heat-resistant substrate 13 and the moisture-resistant substrate 15, have strong rigidity and cannot be measured, and do not exhibit good flexibility. I understood it. From this result, it became clear that the back surface protection sheet 1 with high flexibility is formed by bonding the heat-resistant substrate 13 and the moisture-resistant substrate 15 together using the adhesive 14.

2 is a schematic diagram showing a cross-sectional structure of a solar cell module 100. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Back surface protection sheet 10 for solar cell modules Film 11 Sealing material 12 Solar cell element 13 Heat resistant base material 14 Adhesive 15 Moisture resistant base material 100 Solar cell module

Claims (4)

A heat-resistant substrate that is a heat-treated substrate;
It has a structure in which a moisture resistant base material that is a moisture resistant base material is laminated,
The back protective sheet for solar cell modules, wherein the heat-resistant substrate and the moisture-resistant substrate are bonded together with an adhesive.   The back protective sheet for a solar cell module according to claim 1, wherein the pressure-sensitive adhesive contains a colorant.   The back adhesive sheet for a solar cell module according to claim 1 or 2, wherein the pressure-sensitive adhesive contains an ultraviolet absorber.   The back protective sheet for a solar cell module according to any one of claims 1 to 3, wherein a coating thickness of the pressure-sensitive adhesive after drying is 10 µm or more and 30 µm or less.

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