JP2012222247A - Solar cell sealing material and solar cell module using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing material for a solar cell which exhibits excellent durability on the contact interface with the solar cell surface of inorganic substance, and has excellent steam barrier property and transparency.SOLUTION: The sealing material for a solar cell is composed of a polyolefin resin composition containing a polyolefin resin and/or a graft degeneration thereof, and includes a polyolefin multi-layer sheet including a surface layer sheet C of 0.5-5 μm thick composed of a polyolefin resin composition CRC containing a polyolefin resin and/or 80-99 wt% of resin CR that is a graft degeneration thereof, and 1-20 wt% of a sticker, and a substrate layer sheet B of 50-500 μm thick composed of a polyolefin resin composition BRC containing a polyolefin resin BR which does not contain a component derived from styrene.

Description

  The present invention relates to a solar cell sealing material mainly composed of a polyolefin-based resin and a solar cell module using the same.

  In recent years, solar cells that directly convert sunlight into electric energy have been widely used from the viewpoints of effective use of resources and prevention of environmental pollution. In order to promote further spread of solar cells, performance, long-term reliability, recyclability, productivity and the like required for automobile members and building members are important.

  Generally, a solar cell module includes a solar cell element containing rare metal such as silicon (crystal, polycrystal, amorphous, hybrid), gallium-arsenic, copper-indium-selenium, a light-receiving surface side transparent protective member, and a back surface side protective member. The solar cell element and the protective member are fixed with a sealing material and modularized. Although the configuration of the solar cell module varies slightly depending on the type of the solar cell element described above, since the solar cell module is installed outdoors and exposed to a high humidity environment due to an increase in temperature or wind and rain, moisture is applied to the solar cell element. This may cause a problem that the solar cell element, the electrode, and the like are adversely affected to cause deterioration and decrease in power generation efficiency.

  Currently, as a sealing material for a solar cell element in a solar cell module, an ethylene / vinyl acetate copolymer (EVA) having a thickness of 100 μm to 1500 μm is most commonly used from the viewpoint of flexibility and transparency. Has been. However, the EVA sealing material has poor water vapor barrier properties, and moisture reaches the solar cell element when used in a high humidity environment or when the transparent front substrate or the back surface protective sheet is damaged after long-term use. As a result, the solar cell element, the electrode, and the like are adversely affected, which may cause deterioration and reduction in power generation efficiency. In addition, because of its lack of heat resistance and adhesiveness, it is necessary to use organic peroxides and silane coupling agents together, improve heat resistance by crosslinking, and improve adhesiveness by silane coupling agents. (Patent Document 1). In this case, it is necessary to produce an ethylene / vinyl acetate copolymer sheet containing these additives and to seal the solar cell element using the obtained sheet. In the production stage of this sheet, it is necessary to form at a low temperature so that the organic peroxide is not decomposed, so the extrusion speed cannot be increased, and in the sealing stage of the solar cell element, in the laminator It takes two steps, consisting of a process of temporary bonding for several minutes to ten and several minutes and a process of main bonding for several tens of minutes to several hours at a high temperature at which the organic peroxide decomposes in the oven. It was necessary to go through a crosslinking and adhesion process. Therefore, it takes time and labor to manufacture the solar cell module, which is one of the factors that increase the manufacturing cost. Furthermore, once crosslinked ethylene / vinyl acetate copolymer makes it difficult to recover solar cell elements from defective products generated in, for example, a solar cell module manufacturing process, and even if recovered, it cannot be reused as a sealing material. Therefore, it is inferior in recyclability.

  On the other hand, polyolefin resins such as polypropylene resins are excellent in moldability, flexibility, heat resistance, recyclability, chemical resistance, electrical insulation, etc., and are inexpensive. It is widely used in a wide range of films, fibers, and other shaped articles. On the other hand, a polypropylene-based material is a so-called non-polar and extremely inert polymer substance that does not have a polar group in the molecule, and its solubility in solvents is extremely low. is there. In order to remedy this drawback, a copolymerization of a polymerizable monomer having a polar functional group with ethylene has been studied (Patent Document 2). For example, when a monomer having an epoxy group is copolymerized with ethylene, It is necessary to use an amino group-containing coupling agent as an essential component, and such a copolymer has problems such as industrial difficulty in production and high cost. As a method for producing a modified resin by graft polymerization of a polymerizable monomer having a polar functional group to an olefin resin, the following method has been proposed.

  (I) A method in which a polyolefin resin particle dispersed in water is impregnated with a vinyl monomer and heated in the presence of a peroxide to produce a modified polyolefin (Patent Document 3).

  (Ii) A method for producing a modified polyolefin by melt-kneading a polyolefin resin, maleic anhydride and an organic peroxide (Patent Document 4).

In the method (i), various vinyl monomers can be grafted onto the polyolefin resin. However, a monomer having a highly polar functional group such as an epoxy group is difficult to impregnate a polyolefin resin having a low polarity, so that the amount capable of copolymerization is limited. Moreover, since the dissolution inhibitor of the monomer in water is required, the dissolution inhibitor remains in the modified polyolefin composition after the reaction, and there is a problem that the coating property, adhesion / tackiness are hindered. A technique using a silane-modified resin by polymerizing an ethylenically unsaturated silane compound and a polyethylene for polymerization is disclosed (Reference 5). However, such a copolymer has poor transparency, and when used as a sealing material for a solar cell, the power generation efficiency is lowered and the original performance of the solar cell element cannot be exhibited. In addition, there are problems such as industrial difficulty in production and high cost.

  On the other hand, as a composition having excellent water vapor barrier properties, a method of adding a tackifying resin to a polypropylene resin is known (Patent Document 6). However, this technique is concerned about deterioration of heat resistance, and secondary processing is required to prevent it, which increases the manufacturing cost. Moreover, when this composition is used as a sealing material having a single-layer structure having a thickness of 100 μm to 1500 μm, the composition is colored by a heat and humidity resistance test, thereby causing problems such as deterioration of transparency. Moreover, it is a heat-resistant and moisture-resistant film application for packaging and is not evaluated as a solar cell sealing material, and its performance is unknown.

JP 2005-113077 A JP 2001-144313 A Japanese Patent Laid-Open No. 6-122738 Japanese Patent Laid-Open No. 9-278956 JP 2005-347721 A JP-A-7-157573

  When the water vapor barrier property of the sealing material for solar cells is poor, there is a possibility that moisture may enter in the heat and humidity resistance test and deteriorate the solar cell element. Moreover, when the sealing material has poor transparency, the power generation efficiency is lowered, and the original performance of the solar cell element cannot be exhibited. Therefore, the present invention provides a solar cell sealing material having excellent water vapor barrier properties and transparency for solar cell elements, and excellent long-term stability of solar cell quality, recyclability, and module productivity. An object of the present invention is to provide a solar cell module.

  As a result of intensive investigations in view of the above-mentioned present situation, the present inventors comprise a polyolefin resin and / or a polyolefin resin composition containing a graft modified product thereof as a member (sealing material) of a solar cell module. , A polyolefin resin, and / or a resin CR, which is a graft modified product thereof, and a polyolefin resin composition CRC containing a pressure-sensitive adhesive, and a surface layer sheet C having a thickness of 0.5 to 5 μm, and does not contain a styrene-derived component In the sheet including the polyolefin-based multilayer sheet including the base material layer sheet B having a thickness of 50 to 500 μm made of the polyolefin-based resin composition BRC including the polyolefin-based resin BR, transparency and durability (heat resistance, humidity resistance, cold resistance cycle) ), Ethylene / vinyl acetate copolymer, which has been used as a sealing material for solar cell modules. It has been found that the performance is equal to or higher than that of the body, and the present invention has been completed.

  That is, the present invention is a solar cell encapsulating material used in a solar cell module, comprising a polyolefin resin and / or a polyolefin resin composition containing a graft modified product thereof, and a polyolefin resin, and / or Or a polyolefin-based multilayer sheet comprising a polyolefin-based resin composition CRC obtained by adding an adhesive to a resin that is a graft-modified product thereof, and a polyolefin-based resin composition BRC that does not include a styrene-derived component. The present invention relates to a solar cell sealing material.

Such a solar cell encapsulating material of the present invention preferably has a water vapor transmission rate of 2.0 g / m ² · day or less, more preferably 1.0 g / m ² · day or less per 400 μm thickness. Yes, and more preferably 0.5 g / m ² · day or less.

  As a preferred embodiment, the polyolefin resin and / or the resin CR which is a graft modified product thereof is preferably 80 to 99% by weight, more preferably 85 to 98% by weight, particularly preferably 90 to 95% by weight. . The pressure-sensitive adhesive is preferably 1 to 20% by weight, more preferably 2 to 15% by weight, and particularly preferably 5 to 10% by weight.

  In a preferred embodiment, the polyolefin resin (a) is polyethylene, more preferably low density polyethylene, and a propylene-ethylene copolymer having an ethylene content of 5 to 25 wt%. A polymer is also preferred.

  A preferred embodiment is that the polyolefin resin composition CR is an epoxy-modified polyolefin resin composition in which an epoxy group-containing monomer is introduced into the polyolefin resin (a) by a graft reaction, and more preferably, (A) obtained by melt-kneading (c) an epoxy group-containing vinyl monomer and (d) an aromatic vinyl monomer in the presence of a radical polymerization initiator (b) in a polyolefin-based resin; (C) 1 to 10% by weight of an epoxy group-containing vinyl monomer in a total of 100% by weight of the resin, (c) epoxy group-containing vinyl monomer, and (d) aromatic vinyl monomer, and (d ) Aromatic vinyl monomer is in the range of 0.1 to 5% by weight. Here, (c) the epoxy group-containing vinyl monomer is preferably glycidyl methacrylate, and (d) the aromatic vinyl monomer is preferably styrene.

  In a preferred embodiment, the polyolefin resin composition CRC is particularly preferably added in an amount of 1 to 20 wt% of a terpene resin to a propylene-ethylene copolymer or an epoxy-modified polyolefin resin composition.

  In a preferred embodiment, the pressure-sensitive adhesive is a terpene resin, more preferably a hydrogenated terpene resin.

  As a preferred embodiment, the resin BR which is a polyolefin resin and / or a graft modified product thereof and does not contain a styrene-derived component is that the polyolefin resin is polyethylene, more preferably low density polyethylene. It is also preferable to use a propylene-ethylene copolymer having an ethylene content of 5 to 25 wt%. 100% by weight of the polyolefin resin graft modified BR is added to the polyolefin resin in the presence of a radical polymerization initiator so as to be 1 to 10% by weight of an epoxy group-containing vinyl monomer, and melt kneaded. This is an epoxy-modified polyolefin resin obtained.

  As a preferred embodiment, the polyester-based weather resistant film and the adhesive sheet A in contact with the weather-resistant film preferably have a styrene-derived component in an amount of 3 to 5% by weight based on 100 parts by weight of the polyolefin-based resin graft modified product. ˜4% by weight is more preferred.

  In a preferred embodiment, the polyolefin-based multilayer sheet is a T-die molded sheet obtained by co-extruding the polyolefin-based resin compositions CRC, BRC, and ARC using a multi-manifold or a feed block, and The weather-resistant film is formed by extrusion lamination at the time of the three-layer coextrusion, and can be manufactured at low cost because it is a simple process.

  A preferred embodiment is that the polyolefin resin graft modified CR100% by weight contains an aromatic vinyl monomer-derived component in an amount of 2 to 5% by weight. Since the viscosity can be controlled within a certain range, the co-pushable condition range is widened.

  As a preferable embodiment, the solar cell encapsulating material is a sheet or a film-shaped molded body, and more preferably, the thickness is 50 to 3000 μm.

  Moreover, this invention is a solar cell module sealed with the solar cell sealing material of the said description, Comprising: The said outer layer sheet C is related with the solar cell module which contacts the solar cell surface which consists of an inorganic substance.

  The solar cell sealing material having excellent water vapor barrier properties and transparency with respect to the solar cell element of the present invention is suitably used for improving the long-term stability, recyclability, and module productivity of the solar cell module performance. .

Solar cell sealing material of the present invention Solar cell sealing material of the present invention Crystalline solar cell module Amorphous solar cell module

  Details of the present invention will be described below.

(Solar cell sealing material)
The solar cell encapsulating material of the present invention comprises a polyolefin-based resin composition containing a polyolefin-based resin and / or a graft-modified product thereof, and is adhesive to the polyolefin-based resin and / or the resin that is the graft-modified product. Containing a polyolefin-based multilayer sheet comprising a polyolefin-based resin composition BRC which is a polyolefin-based resin composition CRC and a polyolefin-based resin and / or a graft-modified product thereof and does not contain a styrene-derived component .

(Effect of thin surface sheet C)
The sealing material for solar cells of the present invention exhibits high adhesion to the solar cell surface or glass surface where the surface layer sheet C is an inorganic substance, and also exhibits high adhesion to the base material layer B. It is preferably used as one that provides a solar cell module that excels in resistance.

  Specific examples of the solar cell encapsulating material include, for example, weather resistant film / epoxy modified polyolefin resin composition / polyolefin resin composition / epoxy modified polyolefin resin composition.

  Such a solar cell sealing material according to the present invention is excellent in productivity of the solar cell module because the weather-resistant film is previously formed integrally with the sealing material.

  It is preferable that the manufacturing method of the sealing material for solar cells of this invention bonds together by extrusion lamination.

  The sealing material according to the present invention can be suitably used for any solar cell, but can be particularly suitably used for an amorphous silicon solar cell, a crystalline silicon solar cell, a hybrid solar cell, or the like. Examples of the location of the solar cell include the roof, the rooftops of buildings, factories, schools, public facilities, etc., wall surfaces, coasts, and desert areas.

(Co-extrusion)
The polyolefin-based multilayer sheet according to the present invention is preferably a polyolefin-based double-layer sheet. When the sheet is molded by a melt extrusion method, first, two types of polyolefin-based resin compositions are put into each extruder. It is preferable to supply and heat-melt the resin.

  These resins are preferably pre-dried before being supplied to the extruder. By performing such preliminary drying, foaming of the resin extruded from the extruder can be prevented.

  Although the method of preliminary drying is not particularly limited, for example, the raw material (that is, the epoxy-modified polyolefin resin according to the present invention) can be formed into a pellet or the like and then used with a hot air dryer or the like.

  Next, the resin heated and melted in the extruder is supplied to a co-extrusion T die provided with a feed block immediately before or a multi-manifold type co-extrusion T die. At this time, if a gear pump is used, the uniformity of the extrusion amount of the resin can be improved and thickness unevenness can be reduced.

  In addition, when forming a two-layer sheet or a three-layer sheet by the feed block method, two or three kinds of resins that are heated and melted so that the adhesive layer sheet A or the surface layer sheet C does not partially exist are formed. It is preferable that the melt viscosities of these are matched with the set temperature of the extruder.

  The temperature of the polyolefin resin discharged from the T-die is such that the melt viscosity of the resin is not too high, resulting in uneven thickness of the film, and insufficient adhesion between the films after lamination. 100-300 degreeC is preferable and 170-280 degreeC is more preferable so that a melt viscosity may be too low and shaping | molding may become difficult.

  When forming a two-layer sheet, when forming a surface sheet C / base material layer sheet B, a three-layer sheet of a two-layer sheet, a surface layer sheet C / base material layer sheet B of a two-layer sheet, a surface layer sheet of a three-layer sheet When the thickness ratio of C / base material layer sheet B / adhesive layer sheet A is higher than the ratio of base material layer sheet B to 1/10/1, the film thicknesses of the surface layer sheet C and the adhesive layer sheet A are uniform. It is preferable to use a multi-manifold type co-extrusion T-die from the viewpoint of being able to control it.

(Extruded laminate)
Next, the sheet-like molten resin discharged from the co-extrusion T-die is sandwiched and laminated between two laminating rolls so that the weather-resistant film is in contact with the adhesive layer sheet A side, and the solar cell sealing material of the present invention As a laminated sheet. The weather resistant film used at this time may be a single film or may be a weather resistant film in which a vapor-deposited polyester film is laminated as required.

  Of the two laminate rolls sandwiching the sheet-like molten resin, one is a rigid metal roll having a smooth surface, and the other is a flexible roll having an elastic outer cylinder having a smooth surface and capable of elastic deformation. It is preferable that

  With such a rigid metal roll and a flexible roll provided with a metal elastic outer cylinder, the sheet-like molten resin is sandwiched and laminated, whereby a sheet having good adhesion and surface appearance between the films. Can be obtained.

  There is no restriction | limiting in particular in the lamination pressure of a metal roll and a flexible roll, The grade from which sufficient adhesive force is acquired is preferable.

  The surface temperature of the metal roll is preferably 30 ° C. or higher from the viewpoint of increasing the adhesion between films after lamination. That is, the roll is preferably heated and kept warm during use. In that case, there is a concern that the film that comes into contact with the film relatively deteriorates due to heat shrinkage. Therefore, as the film that comes into contact with the metal roll side, a weather-resistant film that is unlikely to cause performance degradation due to heat shrinkage is preferable.

  On the other hand, the surface temperature of the flexible roll is preferably 100 ° C. or lower so that the thermal contraction of the film in contact with the roll does not become excessive and the performance is not lowered. Therefore, as a film which contacts a flexible roll side, a weather-resistant film whose performance may be reduced by heat shrinkage is preferable.

  In addition, when laminating a vapor-deposited polyester film with a weather resistant film, if the heat shrinks during lamination, the vapor deposition layer may crack, and the water vapor barrier property may be lowered. It is preferable to suppress it, and it is more preferable to suppress it to 3% or less.

  Furthermore, when the vapor deposition surface of the vapor deposition polyester film comes into contact with the laminate roll or the transport roll, the vapor deposition surface may be scratched due to friction with the roll or the like, and the water vapor barrier property may be deteriorated. It is necessary to handle it carefully so that it does not occur.

  As for the film delivery direction, it is preferable to control the shrinkage rate by applying tension to each delivery film during roll feeding. A preferable tension is 0.01 to 100 N / m, and more preferably 0.1 to 50 N / m.

  The method for forming a laminated sheet according to the present invention includes a base material layer sheet B / surface layer sheet C, an adhesive layer sheet A / base material layer sheet B / surface layer sheet C, or a weather resistant film / adhesive layer sheet A / base material layer sheet. If it can shape | mold by the structure of B / surface sheet C, there will be no restriction | limiting in particular, For example, the base material layer shape | molded previously other than the method of laminating a weather-resistant film by extrusion lamination of the polyolefin-type multilayer sheet obtained by coextrusion mentioned above Even if the laminated sheet of the present invention is formed by laminating the adhesive layer sheet A and the weather resistant film on one side of the sheet B by extrusion lamination, and then laminating the surface layer sheet C on the other surface of the base material layer sheet B. good.

(Water vapor permeability)
The solar cell sealing material of the present invention preferably has a water vapor permeability (40 ° C., 90% RH) of 2.0 to 5.0 g / (m ² · day), more preferably 1.0 to 2.0. It can be.

  As a method for measuring the water vapor transmission rate (40 ° C., 90% RH), there is a method described in JIS K 7129.

(Transparency evaluation)
The solar cell sealing material of the present invention preferably has a light transmittance of 80.0 to 100%, more preferably 85.0 to 100% in the wavelength range of 450 to 800 nm.

(Polyolefin multilayer sheet)
The polyolefin-based multilayer sheet according to the present invention is a polyolefin-based resin composition containing at least one polyolefin-based resin selected from the group consisting of polyethylene, polypropylene, and an ethylene-propylene copolymer, and / or a graft modified product thereof. And consisting of
Polyolefin resin composition comprising a surface layer sheet C having a thickness of 0.5 to 5 μm and comprising a polyolefin resin and / or a resin CR 80 to 99 wt%, which is a graft modified product thereof, and an adhesive 1 to 20 wt% A surface sheet C made of a material CRC;
A base material layer sheet B having a thickness of 50 to 500 μm, comprising a polyolefin resin and / or a graft-modified product thereof, and a polyolefin resin composition BRC containing a resin BR not containing a styrene-derived component It is a layer sheet B.

  The polyolefin resin graft modified CR 100% by weight in the presence of a radical polymerization initiator with respect to the polyolefin resin is 1 to 10% by weight of an epoxy group-containing vinyl monomer and 0.1 to 5% by weight of styrene. An epoxy-modified polyolefin resin obtained by addition and melt-kneading, and 100% by weight of the polyolefin resin-grafted modified BR is an epoxy resin in the presence of a radical polymerization initiator with respect to the polyolefin resin. It is an epoxy-modified polyolefin resin obtained by adding 1 to 10% by weight of a group-containing vinyl monomer and melt-kneading.

(Base material layer sheet B)
A base material layer sheet B having a thickness of 50 to 500 μm, comprising a polyolefin resin and / or a graft-modified product thereof, and a polyolefin resin composition BRC containing a resin BR not containing a styrene-derived component It is a layer sheet B.

(Surface sheet C): Adhesive 1-20% by weight in contact with the solar cell surface
Polyolefin resin composition comprising a surface layer sheet C having a thickness of 0.5 to 5 μm and comprising a polyolefin resin and / or a resin CR 80 to 99 wt%, which is a graft modified product thereof, and an adhesive 1 to 20 wt% It is a surface layer sheet C made of a material CRC.

(Polyolefin resin composition)
The polyolefin resin composition according to the present invention is optionally added to one or more polyolefin resins selected from the group consisting of polyethylene, polypropylene, and ethylene-propylene copolymers, and / or graft modified products thereof. It is a composition to which an agent is added.

(Adhesive layer sheet A)
A polyester-based weather resistant film, and an adhesive layer sheet A in contact with the weather-resistant film, which is a polyolefin-based resin composition ARC containing 100% by weight of a polyolefin-based resin graft modified product AR containing 3-5% by weight of a styrene-derived component It is characterized by that.

(Weather-resistant film): polyester-based The weather-resistant film according to the present invention is a film composed of one or more resins selected from the group consisting of polyester-based and fluorine-based, and the polyester-based film is made of an inorganic thin film or an inorganic oxide. It is also a preferred embodiment to make a vapor-deposited PET film or a biaxially stretched PET film on which the vapor-deposited layer is laminated.

Examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), preferably PET.
Examples of the fluorine-based resin include polyethylene fluoride and polyethylene difluoride (polyvinylidene fluoride, PVDF), and PVDF is preferable.

(Constitution)
As shown in FIG. 1, the configuration of the polyolefin-based multilayer sheet according to the present invention is shown in FIG. 2 as a sealing layer (3) consisting of two layers of a surface layer sheet C (1) and a base material layer sheet B (2). In this way, the adhesive layer sheet A (4) and the weather resistant film (5) are laminated on one side of the base layer sheet B (2) of the two-layer sealing layer (3) by extrusion lamination. A sheet may be formed.

(Additive)
Examples of the additives include thermoplastic resins, elastomers, tackifiers (tackifiers), plasticizers, antioxidants, metal deactivators, phosphorus processing stabilizers, UV absorbers, UV stabilizers, fluorescent brighteners, Stabilizers such as metal soaps, antacid adsorbents, radical scavengers, moisture scavengers, or crosslinking agents, chain transfer agents, nucleating agents, lubricants, fillers, reinforcing materials, pigments, dyes, flame retardants, antistatic agents, etc. The additive etc. can be illustrated. Preferable additives are a tackifier and a plasticizer, and it is particularly preferable to add a tackifier.

  Examples of the thermoplastic resin include acrylonitrile-butadiene-styrene copolymer and its hydride, polystyrene, polyvinyl chloride, polymethyl methacrylate, polyurethane, polyester, polylactic acid, and the like.

  Examples of the elastomer include styrene thermoplastic elastomer (TPS), olefin thermoplastic elastomer (TPO), butyl rubber, acrylic rubber, butadiene rubber, isoprene rubber, and styrene-butadiene rubber.

  Examples of the plasticizer include petroleum-based process oils such as paraffinic process oil, naphthenic process oil, aromatic process oil, low molecular weight liquid polymers such as silicone oil, liquid polybutene, and liquid polyisoprene.

  Examples of the radical scavenger include phenol scavengers, phosphorus scavengers, sulfur scavengers, HALS scavengers, and the like. The resin composition according to the present invention preferably contains 0 to 3% by mass.

  Examples of the moisture scavenger include alkaline earth metal oxides, sulfates, silicates, and the like, preferably zeolite, and is preferably contained in the resin composition according to the present invention in an amount of 0 to 20% by mass.

  These additives may be added in advance to the polyolefin resin, may be added when the polyolefin resin is melted, or may be added after the graft-modified product is produced.

(Tackifier) 1-20% by weight
The tackifying resin used in the present invention, that is, the tackifier is not particularly limited. For example, rosin resin (gum rosin, tall oil rosin, wood rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, maleated) Rosin, rosin glycerin ester, hydrogenated rosin / glycerin ester, etc.), terpene phenol resin, terpene resin (mainly α-pinene, β-pinene, dipentene, etc.), aromatic hydrocarbon-modified terpene resin, petroleum resin (aliphatic) , Cycloaliphatic, aromatic, etc.), coumarone / indene resin, styrene resin (styrene, substituted styrene, etc.), phenolic resin (alkylphenol resin, rosin-modified phenol resin, etc.), xylene resin, etc. It is done. These may be used alone or in combination of two or more.

  A preferable tackifier is a low-molecular resin having a number average molecular weight of 300 to 3000 and a softening point based on the ring and ball method defined in JIS K-2207 of 20 ° C. to 200 ° C., more preferably 60 to 150 ° C.

  The tackifying resin used in the present invention is preferably a terpene resin, and is one or more selected from the group consisting of a terpene phenol resin and a hydrogenated terpene resin because of good compatibility and heat resistance. Is more preferable, and a hydrogenated terpene phenol resin is more preferable from the viewpoint of ensuring transparency. Among the terpene phenol resins, it is particularly preferable that the softening point is in the range of 20 ° C. to 200 ° C. and the number average molecular weight is in the range of Mn = 300 to 1200 because of the improvement of compatibility and adhesive strength.

  Specific examples of the hydrogenated terpene resin include: Clearon P type manufactured by Yasuhara Chemical Co., Ltd. (hydrogenated dipentene resin, non-polar, Clearon P-105) and K type produced by Yashara Chemical Co., Ltd. Clearon K-4100,) and M type manufactured by Yashara Chemical Company (hydrogenation of aromatic modified terpene resin, polarity, Clearon M-115).

  Specific examples of the hydrogenated terpene phenol resin include YS Polyster TH130 and UH115 manufactured by Yasuhara Chemical Co., Ltd.

  The amount of the tackifier resin used in the present invention is not particularly limited when blended, but it is 0.1 to 50 parts by weight with respect to 100 parts by weight of the polyolefin resin and the epoxy-modified polyolefin resin composition. Preferably, 0.1-30 weight part is more preferable, 0.3-20 weight part is further more preferable, and 0.5-10 weight part is especially preferable.

(Polyolefin resin)
The polyolefin resin according to the present invention is at least one polyolefin resin selected from the group consisting of polyethylene, polypropylene, and ethylene-propylene copolymer (EPCP), preferably an ethylene-propylene copolymer.

  Examples of the polyethylene include low-density polyethylene (LDPE), high-density polyethylene (HDPE), and linear low-density polyethylene (LLDPE). LDPE is preferable because it can be produced on an industrial scale at a low cost.

  The LLDPE is a low-density polyethylene obtained by copolymerizing ethylene and α-olefin (propylene, butene, hexene, octene, 4-methylpentene, etc.) and introducing short chain branches.

  The polypropylene is preferably a soft polypropylene resin having a heat of fusion of 10 J / g or less (for example, VERSIFY manufactured by Dow Chemical Company).

  Here, as the soft polypropylene resin, ethylene propylene rubber (EPR) may be used in addition to the ethylene-propylene copolymer (EPCP) described later, and this EPR is a block type of polyethylene and polypropylene. Mixtures and the like (for example, Prime TPO of Prime Polymer Co., Ltd., Catalloy which is a reactor TPO of Sun Allomer Co., etc.) are shown.

  The ethylene-propylene copolymer (EPCP) is one or more selected from the group consisting of ethylene, propylene, and 1-butene, 1-hexene, and 1-octene, which are added as necessary. Random copolymer or block copolymer in any ratio, preferably a random copolymer consisting only of ethylene and propylene, and a viewpoint to ensure necessary softness when used as a solar cell sealant More preferably, from the viewpoint of ensuring the necessary laminability, the viewpoint of optimizing the temperature range suitable for adhesion, and the viewpoint of sufficiently allowing the modification reaction to proceed during melt-kneading according to the present invention, more preferably ethylene content Is a polymer of 5 to 25 wt%. Further, these polyolefin resins (which may contain various additive materials) may be in the form of particles or pellets, and the size and shape are not particularly limited.

(Polyolefin resin graft modified)
The modified polyolefin resin according to the present invention is a graft modified product obtained by graft-modifying the polyolefin resin with a polar functional group.

  Examples of the compound containing a polar group used for the modification include maleic anhydride, a vinyl monomer having an epoxy group, a hydroxyl group, a carboxy group, and a nitro group.

  The graft polymerization reaction related to the graft modification is not particularly limited, and solution polymerization, impregnation polymerization, melt polymerization and the like can be used. In particular, melt polymerization is simple and preferable.

  Specifically, the polyolefin resin is preferably a resin composition in which a graft chain composed of a compound containing a polar group used for the modification is grafted in the presence of a radical polymerization initiator, and contains an epoxy group. It is more preferable to use a resin composition grafted with a vinyl monomer, and the aromatic vinyl monomer as an essential component in the polymerization of the graft modified product according to the present invention also has an effect of increasing the graft efficiency.

  There is no restriction | limiting in particular about the addition order and method at the time of the said melt-kneading. In addition, the order and method of mixing and melt-kneading the materials added as necessary are not particularly limited. The heating temperature at the time of melt-kneading is preferably 100 to 250 ° C. from the viewpoint that the polyolefin-based resin is sufficiently melted and is not thermally decomposed. The time for melt kneading (the time after mixing the radical polymerization initiator) is usually 30 seconds to 60 minutes.

(Epoxy group-containing monomer)
Examples of the epoxy group-containing vinyl monomer used in the present invention include glycidyl methacrylate, glycidyl acrylate, monoglycidyl maleate, diglycidyl maleate, monoglycidyl itaconate, diglycidyl itaconate, monoglycidyl allyl succinate, allyl succinate Acid diglycidyl, p-styrene carboxylic acid glycidyl, allyl glycidyl ether, methallyl glycidyl ether, styrene-p-glycidyl ether, p-glycidyl styrene, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl One type or two or more types of epoxy olefins such as -1-butene, vinylcyclohexene monoxide and the like can be mentioned.

  Of these, glycidyl methacrylate and glycidyl acrylate are preferable in terms of low cost, and glycidyl methacrylate is particularly preferable.

  The amount of the epoxy group-containing vinyl monomer added is preferably such that the ratio of the epoxy group-containing vinyl monomer is 0.1 to 100 parts by weight with respect to 100 parts by weight of the polyolefin resin, and 0.5 to 50 parts by weight. Is more preferably 1 to 15 parts by weight, still more preferably 1 to 10 parts by weight, and particularly preferably 1 to 5 parts by weight. If the addition amount is too small, the adhesiveness tends not to be sufficiently improved, and if the addition amount is too large, there is a tendency that it cannot be obtained as a resin composition having a suitable shape and appearance.

(Epoxy-modified polyolefin resin composition)
The epoxy-modified polyolefin resin composition introduced with an epoxy group-containing monomer, which is a preferred graft-modified product of the present invention, is not particularly limited as long as a compound containing an epoxy group is introduced by a graft reaction. Glycidyl methacrylate Examples thereof include modified polyolefin.

  The present inventors have further found that, unlike an acidic functional group whose water vapor barrier property is lowered due to its presence, an epoxy group does not lower the water vapor barrier property and exhibits extremely strong adhesion, particularly adhesion to glass. ing.

(Does not include silane coupling agent)
The epoxy-modified polyolefin resin composition, which is a preferred graft modified product of the present invention, preferably further does not contain a silane coupling agent, and improves the reliability of the solar cell module using the solar cell encapsulating material of the present invention. And can be manufactured at a high yield. That is, the silane coupling agent has difficulty in ensuring reliability due to changes over time, and may lead to a decrease in yield.

(Aromatic vinyl monomer)
Examples of the aromatic vinyl monomer according to the present invention include styrene; methyl styrene such as o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, β-methyl styrene, dimethyl styrene, and trimethyl styrene; o- Chlorostyrene such as chlorostyrene, m-chlorostyrene, p-chlorostyrene, α-chlorostyrene, β-chlorostyrene, dichlorostyrene, trichlorostyrene; o-bromostyrene, m-bromostyrene, p-bromostyrene, dibromostyrene , Bromostyrene such as tribromostyrene; fluorostyrene such as o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, difluorostyrene, trifluorostyrene; o-nitrostyrene, m-nitrostyrene, p-nitros Nitrostyrene such as Len, dinitrostyrene and trinitrostyrene; vinylphenols such as o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene and trihydroxystyrene; o-divinylstyrene, m-divinylstyrene, p -Divinyl styrene such as divinyl styrene; diisopropenyl benzene such as o-diisopropenylbenzene, m-diisopropenylbenzene, p-diisopropenylbenzene; Of these, methylstyrene such as styrene, α-methylstyrene, and p-methylstyrene, divinylbenzene monomer, or divinylbenzene isomer mixture is preferable because it is inexpensive, and styrene is particularly preferable. Said aromatic vinyl monomer can be used individually or in mixture of 2 or more types.

(Radical polymerization initiator)
When graft copolymerizing an epoxy group-containing vinyl monomer to a polyolefin resin, a radical polymerization initiator is added to start the reaction.

  The radical initiator used in the present invention is generally a peroxide or an azo compound.

  Examples of radical initiators include ketone peroxides such as methyl ethyl ketone peroxide and methyl acetoacetate peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t -Peroxyketals such as -butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, permethane hydroperoxide, Hydroperoxides such as 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t- Butylperoxy) hexane, α, α ' Bis (t-butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 Dialkyl peroxides such as dialkyl peroxides such as benzoyl peroxide, peroxydicarbonates such as di (3-methyl-3-methoxybutyl) peroxydicarbonate, di-2-methoxybutylperoxydicarbonate, t- Butyl peroxyoctate, t-butyl peroxyisobutyrate, t-butyl peroxylaurate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxyisopropyl carbonate, 2, 5-Dimethyl-2,5-di (benzoylperoxy Hexane, t- butyl peroxy acetate, t- butyl peroxybenzoate, etc. peroxy esters such as di -t- butyl peroxy isophthalate and the like.

  Among them, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, n-butyl Peroxyketals such as 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, dicumyl peroxide, 2,5-dimethyl-2,5-di ( t-butylperoxy) hexane, α, α′-bis (t-butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2, Dialkyl peroxides such as 5-di (t-butylperoxy) hexyne-3, diacyl peroxides such as benzoyl peroxide; t-butyl -Oxyoctate, t-butyl peroxyisobutyrate, t-butyl peroxylaurate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxyisopropyl carbonate, 2,5 It is preferable to use -dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, t-butylperoxybenzoate, di-t-butylperoxyisophthalate, or the like. Said radical initiator can be used individually or in mixture of 2 or more types.

  The addition amount of the radical polymerization initiator is 0.01 to 100 parts by weight with respect to 100 parts by weight of the polyolefin resin from the viewpoint of sufficiently allowing the modification reaction to proceed and the fluidity and mechanical properties of the resulting modified product. It is preferably 10 parts by weight, and more preferably 0.2 to 5 parts by weight.

(Melt kneading)
As the melt kneading apparatus, an extruder, a Banbury mixer, a mill, a kneader, a heating roll, or the like can be used. From the viewpoint of productivity, a method using a single-screw or twin-screw extruder is preferred. Moreover, in order to mix each material sufficiently uniformly, the melt kneading may be repeated a plurality of times.

  Regarding the order and method of addition at the time of melt kneading, the addition order of melt kneading by adding an epoxy group-containing vinyl monomer and aromatic vinyl monomer to a mixture obtained by melt-kneading a polyolefin resin and a radical polymerization initiator is good. By performing, the production | generation of the low molecular weight body which does not contribute to a graft can be suppressed. In addition, the order and method of mixing and melt-kneading the materials added as necessary are not particularly limited.

  The heating temperature at the time of melt kneading is preferably 130 to 300 ° C. from the viewpoint that the polyolefin-based resin is sufficiently melted and is not thermally decomposed. The time for melt kneading (the time after mixing the radical polymerization initiator) is usually 30 seconds to 60 minutes.

  The method for producing a sheet-like molded product obtained using the polyolefin resin composition of the present invention is not particularly limited. For example, an epoxy-modified polyolefin resin composition and other compounding agents are dry blended and melt-kneaded. After that, it can be formed into a sheet-like molded body using various types of extrusion molding machines, injection molding machines, calendar molding machines, inflation molding machines, roll molding machines, or hot press molding machines.

The solar cell module of this invention is obtained by sealing the cell for solar cells through the polyolefin-type multilayer sheet which concerns on this invention between the light-receiving surface side transparent protective member and the back surface side protective member. In the solar cell module, in order to sufficiently seal the solar cell, there are roughly two sealing methods, crystalline and amorphous. In the case of a crystalline solar cell, as shown in FIG. 3, the light receiving surface side transparent protective member (6), the light receiving surface side sealing material (8A), the solar cell (9), the back surface side sealing material (8B). ) And back surface side protection member (7), and in the case of amorphous, as shown in FIG. 4, the light receiving surface side transparent protective member (6), the solar cell (9) (light receiving surface side transparent protection) The back surface side sealing material (8B) and the back surface protection member (7) are laminated, and are integrally formed with a vacuum laminator. Integrated molding with a vacuum laminator is performed at a temperature of 135 to 180 ° C., further 140 to 180 ° C., particularly 155 to 180 ° C., a degassing time of 0.1 to 5 minutes, a press pressure of 0.1 to 1.5 kg / cm ² , What is necessary is just to heat-press in press time 5-15 minutes. At the time of heating and pressing, a polyolefin resin used for the light-receiving surface side sealing material (8A) and / or the back surface side sealing material (8B) added with a tackifying resin, an epoxy group-containing single amount by graft reaction The epoxy-modified polyolefin resin composition into which the body is introduced, and the sealing sheet obtained by using the composition obtained by adding a tackifying resin to the light-receiving surface side transparent protective member (6), the back surface side transparent member ( 7) and solar cell (9) can be sealed and integrated to seal solar cell (9). By using the encapsulant of the present invention for a solar cell having such a configuration, the encapsulant is used for a long period of time. It is possible to suppress a decrease in power generation performance and to have excellent durability.

  The light-receiving surface side transparent protective member used in the present invention is used in the form of a film, a sheet, or a plate. Usually, a material having practical strength and transparency such as a silicate glass or a polycarbonate plate is used, and a glass substrate is particularly preferable. As for the thickness of a glass substrate, 0.1-10 mm is common, and 0.3-5 mm is preferable. The glass substrate may generally be chemically or thermally strengthened.

  The back surface protection member used in the present invention is used in the form of a film, a sheet, or a plate. A laminated body of glass, aluminum foil, or plastic film is preferably used for the back surface protection member. Examples of the resin used for the plastic film include polyvinyl fluoride, polyethylene terephthalate, polyethylene naphthalate, polyethylene, and tetrafluoroethylene. -An ethylene copolymer etc. are mentioned, However, It is not limited to these. The back surface protection member is a single layer or a laminate having heat resistance, moisture resistance, weather resistance, and insulation generally called a back sheet.

  In addition, the solar cell of this invention has the characteristics in the sealing material used for the light-receiving surface side and / or back surface side as above-mentioned. Therefore, members other than the sealing material such as the light-receiving surface side transparent protective member, the back surface side protective member, and the solar battery cell are not particularly limited, and may have the same configuration as a conventionally known solar battery. That's fine.

  Specific examples are shown below, but the present invention is not limited to the following examples. In the following examples and comparative examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

(Evaluation of water vapor barrier properties)
This is a value measured in accordance with JIS K7126-1 (differential pressure method) under the conditions of 40 ° C./90% RH, permeation area 15.2 cm 2, pressure difference 75 cmHg, and expressed in units of g / m ² · day / 0.4 mm.
A: Less than 2.0 (g / m ² · day / 0.4 mm) ○: 2.0 (g / m ² · day / 0.4 mm) or more and 5.0 (g / m ² · day / 0.4 mm) Less than 0.4 mm) x: 5.0 (g / m ² · day / 0.4 mm) or more

(Transparency evaluation)
The light transmittance was measured at a test speed of 200 nm / min in a wavelength range of 450 to 800 nm by an integrating sphere method using a UV-VIS apparatus manufactured by JASCO Corporation. The test sample was produced by the following method. White slide glass (0.9 mm thickness, manufactured by Matsunami Glass Co., Ltd.) / Test sample / White slide glass (0.9 mm thickness, manufactured by Matsunami Glass Co., Ltd.) using a vacuum laminator (NPC, LM-50 × 50-S) Crimped. The integral molding conditions were 170 ° C., degassing time 3.5 minutes, press pressure 1 kg / cm ² , and press time 10 minutes.
○: 85.0% or more ×: less than 85.0%

(Adhesion evaluation)
For the adhesive strength with glass, AG-2000A manufactured by Shimadzu Corporation was used, and a 180 ° peel test was performed at 23 ° C. and a tensile test speed of 50 mm / min. The test sample was produced by the following method.

Glass / test sample (surface layer sheet C / base material layer sheet B (/ adhesive sheet A), 400 μm thickness) / solar cell seal with the surface layer sheet C on the glass (3.2 mm thickness, manufactured by AGC) side A back sheet for stop (TOYAL SOLAR FA20 / AL30 / BPET50 / LE50, manufactured by Toyo Aluminum Co., Ltd.) was pressure-bonded with a vacuum laminator (NPC, LM-50 × 50-S). The conditions for integral molding were 170 ° C., degassing time 5 minutes, press pressure 1 kg / cm ² , and press time 15 minutes.

The adhesive strength with glass was evaluated according to the following criteria.
A: It is not peeled off by hand.
○: It is not easily peeled off by hand.
X: It peels easily by hand.

(Evaluation of heat and humidity resistance of solar cell modules)
Using the solar cell encapsulant sheet of the present invention, a solar cell hybrid substrate (a material in which silicon or the like is vapor-deposited and processed on glass to form a power generation element) and a back sheet (manufactured by Toyo Aluminum Co., Ltd.) : TOYAL SOLAR FA20 / AL30 / BPET50 / LE50), the sheet for solar cell encapsulant of the present invention having a width of 50 mm and a length of 50 mm was sandwiched and integrally formed with a vacuum laminator (Spi-Laminator). The conditions for the integral molding were 170 ° C., degassing time of 3.5 minutes, press pressure of 1 kg / cm 2, and thermocompression bonding with a pressing time of 10 minutes to obtain a solar cell module. When EVA-based resin is used as the sealing material, the integral molding conditions are 170 ° C., degassing time 3.5 minutes, press pressure 1 kg / cm 2, press pressure 3.5 mm, and press-bonding at 150 ° C. The solar cell module was obtained by heating in an oven for 120 minutes to crosslink EVA.

  The produced solar cell module was irradiated with pseudo-sunlight at 25 ° C. and an irradiation intensity of 1000 mW / cm 2 by a solar simulator whose spectrum was adjusted to AM 1.5, and the open voltage [V] of the solar cell and the nominal maximum per cm 2 The output operating current [A] and the nominal maximum output operating voltage [V] were measured, and the initial value of the nominal maximum output [W] (JIS C8911 1998) was determined from these products.

Next, the solar cell module is allowed to stand for 500 hours in an environment of a temperature of 85 ° C. and a humidity of 85% RH, and a heat and humidity resistance test is performed. ] And the superiority or inferiority of the heat and humidity resistance was determined. The judgment of superiority or inferiority was made as follows.
○: The value obtained by dividing the nominal maximum output after the 500 hour heat and humidity resistance test by the initial value is 0.95 or more ×: The value obtained by dividing the nominal maximum output after the 500 hour heat and humidity resistance test by the initial value is less than 0.95

(Evaluation of thermal cycle resistance of solar cell modules)
The solar cell module produced by the above method was irradiated with pseudo-sunlight of 25 ° C. and an irradiation intensity of 1000 mW / cm 2 by a solar simulator whose spectrum was adjusted to AM 1.5, and the open voltage [V] of the solar cell and per 1 cm 2. The nominal maximum output operating current [A] and the nominal maximum output operating voltage [V] were measured, and the initial value of the nominal maximum output [W] (JIS C8911 1998) was determined from these products.

Next, the manufactured solar cell module is left for 200 cycles in an environment where the temperature is −40 ° C. to + 85 ° C. (temperature increase / decrease rate of 100 ° C./hr) for one cycle, and a thermal cycle test is performed. For the battery module, the nominal maximum output [W] was determined in the same manner as described above, and the superiority or inferiority of the cold-heat cycle resistance was determined. The judgment of superiority or inferiority was made as follows.
○: The value obtained by dividing the nominal maximum output after the 200-cycle thermal cycle test by the initial value is 0.95 or more. X: The value obtained by dividing the nominal maximum output after the 200-cycle thermal cycle test by the initial value is less than 0.95.

(Recyclability evaluation)
Between 50 mm wide and 100 mm long solar cell hybrid substrate (a material in which silicon or the like is vapor-deposited and processed on glass to form a power generation element) and a back sheet (Toyo Aluminum Co., Ltd .: TOYAL SOLAR FA20 / AL30 / BPET50 / LE50) The sheet for solar cell encapsulant of the present invention having a width of 50 mm and a length of 50 mm was sandwiched between and integrally formed with a vacuum laminator (Spi-Laminator). The conditions for the integral molding were 170 ° C., degassing time of 3.5 minutes, press pressure of 1 kg / cm 2, and thermocompression bonding with a pressing time of 10 minutes to obtain a sample for recycling evaluation. When EVA-based resin is used as the sealing material, the integral molding conditions are 170 ° C., degassing time 3.5 minutes, press pressure 1 kg / cm 2, press pressure 3.5 mm, and press-bonding at 150 ° C. EVA was cross-linked by heating in an oven for 120 minutes. After peeling off only the sealing material from the sample for evaluation and pulverizing it, it was judged whether or not it could be formed into a sheet when heated at 200 ° C. for 1 minute (50 kgf / cm 2).
○: Can be formed into a sheet.
X: Cannot be formed into a sheet.

Example 1
Polypropylene ethylene rubber (D340 Chemicals V3401, MFR = 8) in 100 parts by weight, 1,3-di (t-butylperoxyisopropyl) benzene (Nippon Yushi Co., Ltd .: Perbutyl P, 1 minute half-life 175 ° C.) After feeding 0.5 parts by weight to a twin-screw extruder (TEX30: L / D = 28, manufactured by Nippon Steel), set to 200 ° C. and melt-kneading, 5 parts by weight of glycidyl methacrylate from the middle of the cylinder, 5 parts by weight of styrene was added and melt kneaded to obtain a styrene-containing epoxy-modified polyolefin resin RC.

  100 parts by weight of the resulting styrene-containing epoxy-modified polyolefin resin composition RC and 10 parts by weight of terpene phenol resin (manufactured by Yasuhara Chemical Co., Ltd .: YS Polystar T130) were set at 200 ° C. (TEX30: L / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain an adhesive-containing epoxy-modified polyolefin resin composition CRC1.

  The obtained pressure-sensitive adhesive-containing epoxy-modified polyolefin resin composition CRC1 and the polypropylene ethylene rubber B1 resin are coextruded with a multi-manifold die, and are composed of a surface layer sheet C made of CRC1 having a thickness of 3 μm and B1 having a thickness of 400 μm. A solar cell sealing sheet made of the base material layer sheet B was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 2)
Polypropylene ethylene rubber (D340 Chemicals V3401, MFR = 8) in 100 parts by weight, 1,3-di (t-butylperoxyisopropyl) benzene (Nippon Yushi Co., Ltd .: Perbutyl P, 1 minute half-life 175 ° C.) After feeding 0.5 parts by weight to a twin-screw extruder (TEX30: L / D = 28, manufactured by Nippon Steel), set to 200 ° C. and melt-kneading, 5 parts by weight of glycidyl methacrylate was then added from the middle of the cylinder. In addition, melt-kneading was carried out to obtain a styrene-free epoxy-modified polyolefin resin composition BRC1.

  The obtained styrene-free epoxy-modified polyolefin resin composition BRC1 and the pressure-sensitive adhesive-containing epoxy-modified polyolefin resin composition CRC1 obtained in Example 1 were coextruded with a multi-manifold die and consisted of CRC1 having a thickness of 3 μm. A solar cell sealing sheet made of a surface layer sheet C and a base material layer sheet B made of BRC1 having a thickness of 400 μm was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 3)
A twin-screw extruder (TEX30: L / D) in which 100 parts by weight of polypropylene ethylene rubber (D340 Chemical V3401, MFR = 8) and 10 parts by weight of terpene phenol resin (Yasuhara Chemical Co., Ltd .: YS Polystar T130) are set at 200 ° C. = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain a pressure-sensitive adhesive-containing polyolefin resin composition CRC2.

  The obtained pressure-sensitive adhesive-containing polyolefin-based resin composition CRC2 resin and the polypropylene ethylene rubber B1 resin were coextruded with a multi-manifold die, a surface sheet C made of CRC2 having a thickness of 3 μm, and a base made of B1 having a thickness of 400 μm. A solar cell sealing sheet made of the material layer sheet B was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

Example 4
The styrene-free epoxy-modified polyolefin resin composition BRC1 and the pressure-sensitive adhesive-containing polyolefin resin composition CRC2 are co-extruded with a multi-manifold die, and a surface sheet C made of CRC2 having a thickness of 3 μm, and BRC1 having a thickness of 400 μm. The solar cell sealing sheet which consists of the base material layer sheet B which consists of was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 5)
A twin-screw extruder (TEX30: L / L) in which 100 parts by weight of the epoxy-modified polyolefin resin composition RC obtained in Example 1 and 10 parts by weight of a hydrogenated terpene resin (manufactured by Yashara Chemical Co., Ltd .: Clearon P105) are set at 200 ° C. D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain a resin CRC3.

  The obtained CRC3 resin and the polypropylene ethylene rubber B1 resin are coextruded by a multi-manifold die, and are used for sealing a solar cell comprising a surface layer sheet C made of CRC3 having a thickness of 3 μm and a base material layer sheet B made of B1 having a thickness of 400 μm. A sheet was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 6)
The resin CRC3 obtained in Example 5 and the BRC1 resin obtained in Example 2 were coextruded with a multi-manifold die, and a surface layer sheet C made of CRC3 having a thickness of 3 μm and a base material layer sheet B made of BRC1 having a thickness of 400 μm. A sheet for sealing a solar cell was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 7)
A twin-screw extruder (TEX30: L / L) in which 100 parts by weight of the epoxy-modified polyolefin resin composition RC obtained in Example 1 and 10 parts by weight of a hydrogenated terpene resin (manufactured by Yashara Chemical Co., Ltd .: Clearon K4100) are set at 200 ° C. D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain a resin CRC4.

  The obtained CRC4 resin and the polypropylene ethylene rubber B1 resin are co-extruded by a multi-manifold die, and are used for sealing a solar cell comprising a surface layer sheet C made of CRC4 having a thickness of 3 μm and a base material layer sheet B made of B1 having a thickness of 400 μm. A sheet was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 8)
The resin CRC4 obtained in Example 7 and the BRC1 resin obtained in Example 2 were coextruded with a multi-manifold die, and a surface layer sheet C made of CRC4 having a thickness of 3 μm and a base material layer sheet B made of BRC1 having a thickness of 400 μm. A sheet for sealing a solar cell was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

Example 9
A twin-screw extruder (TEX30: L / L) in which 100 parts by weight of the epoxy-modified polyolefin resin composition RC obtained in Example 1 and 10 parts by weight of a hydrogenated terpene resin (manufactured by Yashara Chemical Co., Ltd .: Clearon M115) are set at 200 ° C. D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain a resin CRC5.

  The obtained CRC5 resin and the polypropylene ethylene rubber B1 resin are co-extruded by a multi-manifold die, and are used for sealing a solar cell comprising a surface layer sheet C made of CRC5 having a thickness of 3 μm and a base material layer sheet B made of B1 having a thickness of 400 μm. A sheet was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 10)
The resin CRC5 obtained in Example 9 and the BRC1 resin obtained in Example 2 were coextruded by a multi-manifold die, and a surface layer sheet C made of CRC5 having a thickness of 3 μm and a base material layer sheet B made of BRC1 having a thickness of 400 μm. A sheet for sealing a solar cell was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 11)
A twin-screw extruder (TEX30: 100 parts by weight of the epoxy-modified polyolefin resin composition RC obtained in Example 1 and 10 parts by weight of a hydrogenated terpene phenol resin (Yasuhara Chemical Co., Ltd .: YS Polystar UH115) set at 200 ° C. L / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain a resin CRC6.

  The obtained CRC6 resin and the polypropylene ethylene rubber B1 resin are co-extruded by a multi-manifold die, and are used for sealing a solar cell comprising a surface layer sheet C made of CRC6 having a thickness of 3 μm and a base material layer sheet B made of B1 having a thickness of 400 μm. A sheet was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 12)
The resin CRC6 obtained in Example 11 and the BRC1 resin obtained in Example 2 were coextruded with a multi-manifold die, and a surface layer sheet C composed of CRC6 having a thickness of 3 μm and a base material layer sheet B composed of BRC1 having a thickness of 400 μm. A sheet for sealing a solar cell was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 13)
A twin-screw extruder (TEX30: 100 parts by weight of the epoxy-modified polyolefin resin composition RC obtained in Example 1 and 10 parts by weight of a hydrogenated terpene phenol resin (manufactured by Yasuhara Chemical Co., Ltd .: YS Polystar TH130) was set at 200 ° C. L / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain a resin CRC7.

  The obtained CRC7 fat and the polypropylene ethylene rubber B1 resin are co-extruded by a multi-manifold die, and are used for sealing a solar cell comprising a surface layer sheet C made of CRC7 having a thickness of 3 μm and a base material layer sheet B made of B1 having a thickness of 400 μm. A sheet was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 14)
The resin CRC7 obtained in Example 13 and the BRC1 resin obtained in Example 2 were coextruded with a multi-manifold die, and a surface layer sheet C made of CRC7 having a thickness of 3 μm and a base material layer sheet B made of BRC1 having a thickness of 400 μm. A sheet for sealing solar cells was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Example 15)
400 mm width provided with a feed block immediately before using an extruder corresponding to the three resin compositions of CRC7, epoxy-modified polyolefin resin composition BRC1, and RC (ARC as an adhesive sheet) obtained in Example 13 A molten resin is supplied to a co-extrusion T-die, and includes a surface layer sheet C made of CRC7 having a thickness of 3 μm, a base material layer sheet B made of BRC1 having a thickness of 400 μm, and the styrene-containing epoxy-modified polyolefin resin RC having a thickness of 50 μm. A three-layer polyolefin-based multilayer sheet composed of the adhesive sheet A was extruded.

  A weather resistant PET film (Shine Beam K1653, manufactured by Toyobo Co., Ltd., thickness 50 μm) was laminated on the adhesive sheet A side of the polyolefin-based multilayer sheet while being sandwiched between a metallic roll and a silicon rubber film roll to obtain a laminated film. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Comparative Example 1)
A case where polypropylene ethylene rubber (D340 Chemical V3401, MFR = 8) is used as a base material layer is called B1 resin. When used as a surface layer, it will be called C1 resin.

  C1 resin and BRC1 resin obtained in Example 2 were co-extruded with a multi-manifold die, and a surface layer sheet C made of C1 having a thickness of 3 μm and a base material layer sheet B made of BRC1 having a thickness of 400 μm for sealing a solar cell A sheet was obtained. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Comparative Example 2)
Polypropylene ethylene rubber (D340 Chemicals V3401, MFR = 8) in 100 parts by weight, 1,3-di (t-butylperoxyisopropyl) benzene (Nippon Yushi Co., Ltd .: Perbutyl P, 1 minute half-life 175 ° C.) After supplying 0.5 part by weight to a twin screw extruder (TEX30: L / D = 28, manufactured by Nippon Steel), set to 200 ° C. and melt-kneading, then 1 part by weight of glycidyl methacrylate from the middle of the cylinder, 9 parts by weight of styrene was added and melt-kneaded to obtain an epoxy-modified polyolefin resin composition RC2.

  When the obtained RC2 resin is used as a base material layer, it is called BRC2, and when the polypropylene ethylene rubber (D340 Chemicals V3401, MFR = 8) B1 resin is used as a surface layer, it is called C1 resin.

  BRC2 resin and C1 resin were coextruded with a multi-manifold die to obtain a solar cell sealing sheet composed of a surface layer sheet C composed of C1 having a thickness of 3 μm and a base material layer sheet B composed of BRC2 having a thickness of 400 μm. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Comparative Example 3)
When the RC2 resin obtained in Comparative Example 2 is used as a surface layer, it will be referred to as CRC8.

  B1 resin and CRC8 resin were coextruded with a multi-manifold die to obtain a solar cell sealing sheet consisting of a surface layer sheet C made of CRC8 having a thickness of 3 μm and a base material layer sheet B made of B1 having a thickness of 400 μm. Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(Comparative Example 4)
A solar cell module was manufactured using a commercially available EVA sheet for sealing a solar cell (manufactured by Sunvic Co., Ltd .: Ultra Pearl, 0.40 mm thickness). Table 1 shows the results of water vapor barrier property evaluation, transparency evaluation, adhesion evaluation, heat and moisture resistance evaluation, cold and heat cycle resistance evaluation, and recyclability evaluation.

(1) Surface layer C
(2) Base material layer B
(3) Sealing material layer (4) Adhesive layer A
(5) Weather-resistant film (6) Light-receiving surface side transparent protective member (7) Back surface-side transparent protective member (8A) Light-receiving surface side sealing material (8B) Back surface side sealing material (9) Solar cell

Claims (6)

A solar cell sealing material including a polyolefin-based multilayer sheet,
The polyolefin-based multilayer sheet is composed of a polyolefin-based resin composition containing at least one polyolefin-based resin selected from the group consisting of polyethylene, polypropylene, and an ethylene-propylene copolymer, and / or a graft modified product thereof, And,
Polyolefin resin composition comprising a surface layer sheet C having a thickness of 0.5 to 5 μm and comprising a polyolefin resin and / or a resin CR 80 to 99 wt%, which is a graft modified product thereof, and an adhesive 1 to 20 wt% A surface layer sheet C made of a product CRC, and a base layer sheet B having a thickness of 50 to 500 μm, a polyolefin resin and / or a graft modified product thereof, and a polyolefin containing a resin BR not containing a styrene-derived component The solar cell sealing material containing the base material layer sheet B which consists of a resin composition BRC. The resin CR is a polyolefin-based resin graft-modified product, and 100% by weight of the polyolefin-based resin graft-modified product CR is in the presence of a radical polymerization initiator with respect to the polyolefin-based resin, and an epoxy group-containing vinyl monomer 1 An epoxy-modified polyolefin-based resin obtained by adding to 10 wt% and styrene 0.1 to 5 wt% and melt-kneading, and
The solar cell sealing material according to claim 1, wherein the resin BR is a polyolefin-based resin.   The solar cell sealing material according to claim 1 or 2, wherein the polyolefin-based multilayer sheet is a T-die molded sheet obtained by coextruding the polyolefin-based resin composition BRC and CRC using a multi-manifold. The polyolefin-based multilayer sheet is in contact with the base material layer sheet B, and further includes an adhesive sheet A,
The solar cell encapsulating material according to claim 1 or 2, further comprising a polyester-based weather resistant film in contact with the adhesive sheet A,
The adhesive sheet A is made of a polyolefin resin composition ARC, and
The polyolefin resin composition ARC is 1 to 10% by weight of an epoxy group-containing vinyl monomer and 0.1 to 5% by weight of styrene in the presence of a radical polymerization initiator with respect to the polyolefin resin. A solar cell sealing material comprising 100% of an epoxy-modified polyolefin resin AR obtained by adding and melt-kneading.   Furthermore, the solar cell sealing material of Claim 4 provided with a fluororesin coat layer in the surface on the opposite side of the said adhesive sheet A of the said polyester-type weatherproof film. A solar cell module sealed with the solar cell sealing material according to claim 1,
A solar cell module in which the surface layer C is in contact with a solar cell surface made of an inorganic material.

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