WO2014091973A1

WO2014091973A1 - Laminated sheet and method for manufacturing same, solar cell back sheet, solar cell module, and method for manufacturing solar cell back sheet

Info

Publication number: WO2014091973A1
Application number: PCT/JP2013/082533
Authority: WO
Inventors: 堀江　将人; 規行巽; 柴田　優; 高橋　弘造; 崇荒井; 網岡　孝夫
Original assignee: 東レ株式会社
Priority date: 2012-12-10
Filing date: 2013-12-04
Publication date: 2014-06-19
Also published as: KR20150095635A; CN104822528B; JPWO2014091973A1; TWI604951B; TW201429717A; CN104822528A; JP6287829B2

Abstract

A laminated sheet having: a layer having a polybutylene terephthalate resin as a principal component (P1 layer); and a layer having a polyolefin resin as a principal component (P3 layer). A solar cell back sheet, characterized in that the acetic acid permeability (Pa) (g/m²/day) at 85°C and water vapor permeability (Pw) (g/m²/day) at 40°C 90% RH satisfy relationships (1) 200 ≤ Pa and (2) Pw ≤ 2.5. Provided are a laminated sheet having a better moist heat resistance and an improved capacity to obtain both heat resistance and adhesion performance with respect to a sealing member compared with a conventional laminated sheet in which a polybutylene terephthalate resin is used, and a method for manufacturing the laminated sheet. Also provided are a solar cell module back sheet that is inexpensive and that is capable of preventing discoloration of the collector electrode of a solar cell while maintaining the power generation characteristics of the solar cell module over a long period, and a method for manufacturing the solar cell module back sheet.

Description

LAMINATED SHEET AND METHOD FOR MANUFACTURING SAME, SOLAR CELL BACK SHEET, SOLAR CELL MODULE, AND SOLAR CELL BACK SHEET

The present invention relates to a laminated sheet capable of achieving both durability and adhesion with a sealing material. In particular, the present invention relates to a laminated sheet that can be suitably used as a solar battery backsheet, and a method for producing the laminated sheet. Furthermore, it is related with the back seat | sheet which contributes to the long-term reliability improvement of a solar cell module.

In recent years, photovoltaic power generation has attracted attention as a semi-permanent and pollution-free next-generation energy source, and solar cells are rapidly spreading. A solar cell is composed of a power generation element sealed with a transparent sealing material such as ethylene-vinyl acetate copolymer (EVA), and a transparent substrate such as glass and a resin sheet called a back sheet bonded together. The Sunlight is introduced into the solar cell through the transparent substrate. Sunlight introduced into the solar cell is absorbed by the power generation element, and the absorbed light energy is converted into electrical energy. The converted electric energy is taken out by a lead wire connected to the power generation element and used for various electric devices. Here, the structure which provides barrier property and an electrical property by pasting together various raw materials to the biaxially-stretched polyethylene terephthalate (PET) which is a low-cost and high-performance is studied. In addition to the barrier property, polyolefin resin is a material generally used as a back sheet because of its good adhesion to the sealing material.

On the other hand, in order to increase the durability and productivity of the backsheet, application of resin materials other than PET has been studied, and a backsheet (Patent Document 1) in which a polybutylene terephthalate resin and a polycarbonate resin are laminated or a polybutylene terephthalate resin. A back sheet (Patent Document 2) using a lip has been developed.

Moreover, it is known that the solar cell module is easily deteriorated in a high-temperature and high-humidity environment, and there is an urgent need to improve the heat and humidity resistance. Especially for sealing materials used in solar cell modules, EVA is often used from the viewpoints of weather resistance, transparency, productivity, etc., but generation of acetic acid has been a concern due to high-temperature steam. .

Therefore, at the time of manufacturing the solar cell module, until now, for example, as described in Patent Document 3, a material having a low water vapor transmission rate is selected for the back sheet, and the generation of acetic acid is suppressed by suppressing the ingress of moisture. There is also an invention that suppresses the output characteristics of the solar cell module from changing for a long time.

Further, as in Patent Document 4, there is also an invention of a solar cell module sealing material in which output characteristics do not change for a long time by suppressing acetic acid generated from EVA.

JP 2009-141345 A International Publication No. 2010/018662 JP 2012-199379 A JP 2008-115344 A

However, polybutylene terephthalate resin generally has inferior moisture and heat resistance, and further has a drawback of poor adhesion to a sealing material. In addition, the back sheet described in Patent Document 1 in which a polybutylene terephthalate resin and a polycarbonate resin are laminated has improved moisture and heat resistance, but does not provide adhesion to a sealing material, and has a problem of delamination. In addition, the backsheet described in Patent Document 2 is also difficult to achieve both wet heat resistance and adhesion between the sealing material. Therefore, in view of the conventional problems, the present invention provides a laminated sheet that has high productivity and can be suitably used for a solar battery backsheet that has both durability and adhesion with a sealing material.

Furthermore, in Patent Document 3, an inorganic vapor deposition film or the like is often used when the water vapor transmission rate is lowered, and when the inorganic vapor deposition film is used, there is a problem that the cost becomes very high as compared with the case where it is not used. there were. On the other hand, when the water vapor transmission rate is high, each metal material used in the solar battery cell is corroded by moisture, and in particular, discoloration may occur due to corrosion of the collecting electrode of the solar battery cell.

Further, in Patent Document 4, there is a concern about the effect of adding an additive to EVA, and the change of EVA adjacent to the solar battery cell requires a large amount of verification work for change.

The present invention has been conceived in view of the above problems. That is, the present invention provides a back sheet for a solar cell module that is inexpensive, can maintain the power generation characteristics of the solar cell module for a long period of time, and prevents discoloration of the current collecting electrode of the solar cell. The purpose is to do.

In order to solve the above problems, the present invention has the following configuration.

1st invention is a lamination sheet which has a layer (P1 layer) which uses polybutylene terephthalate resin as the main component, and a layer (P3 layer) which uses polyolefin resin as the main component.

The second invention has a layer (P2 layer) mainly composed of an adhesive polyolefin-based resin, and the P1 layer and the P3 layer are in contact with each other through the P2 layer.

The third invention is characterized in that the thickness of the P2 layer is 15 to 50 μm.

The fourth invention is characterized in that the crystallization parameter ΔTcg of the P1 layer measured using differential scanning calorimetry (DSC) is 7 to 30 ° C.

According to a fifth aspect of the present invention, when a resin obtained by reacting an end-capping agent with a polybutylene terephthalate resin is used as an end-capped polybutylene terephthalate resin, the polybutylene terephthalate resin that is the main component of the P1 layer is And end-capped polybutylene terephthalate resin.

The sixth invention is characterized in that the P3 layer contains 0.1 to 30% by mass of inorganic particles.

The seventh invention is characterized in that the rigid amorphous amount of the P1 layer is 30 to 50%.

The eighth invention is characterized in that the P1 layer contains 0.1 to 5% by mass of a crystal nucleating agent.

The ninth invention is characterized in that the P3 layer contains 5 to 30% by mass of inorganic particles having a particle diameter of 3 to 20 μm and 0.5 to 5% by mass of an adhesive polyolefin resin.

In the tenth aspect of the invention, the acetic acid permeability Pa (g / m ² / day) at 85 ° C. and the water vapor permeability Pw (g / m ² / day) at 40 ° C. and 90% RH are expressed by the formula (1) 200 ≦ Pa and the expression (2) Pw ≦ 2.5 are satisfied.

11th invention is a solar cell backsheet which consists of a lamination sheet concerning one of the above-mentioned inventions.

The twelfth invention is a solar cell using the solar cell backsheet according to the eleventh invention.

A thirteenth invention is a method for manufacturing a laminated sheet according to any one of the second to tenth inventions, wherein the raw material for the P1 layer mainly comprises a polybutylene terephthalate resin, and the main structure is an adhesive polyolefin resin. The raw material for the P2 layer, which is the component, and the raw material for the P3 layer, the main component of which is a polyolefin resin, are supplied to different extruders, and after melting, the P1, P2, and P3 layers are joined together in this order. It is made to laminate | stack, and it is the manufacturing method of a lamination sheet characterized by including the process extruded from a T die to a sheet form.

In the fourteenth aspect, the acetic acid permeability Pa (g / m ² / day) at 85 ° C. and the water vapor permeability Pw (g / m ² / day) at 40 ° C. and 90% RH are expressed by the formula (1) 200 ≦ It is a solar cell back sheet | seat characterized by satisfy | filling Pa and Formula (2) Pw <= 2.5.

According to a fifteenth aspect of the present invention, in the fourteenth aspect, when the layer, which is one of the main constituents selected from the group consisting of a polyester resin, a polyamide resin, and a fluororesin, is a P4 layer, it has a P4 layer. Features.

A sixteenth aspect of the present invention is the solar cell backsheet according to the fifteenth aspect of the present invention, wherein the layer mainly composed of the olefin resin is a P6 layer, and the P6 layer has a P4 layer and a P6 layer. Contains inorganic particles, the P4 layer is located on the surface layer, the P6 layer is located on the surface opposite to the P4 layer, the thickness of the entire backsheet is Ta (μm), the thickness of the P4 layer is T4 (μm), and the P6 layer When the thickness of T6 (μm) and the content of inorganic particles in the P6 layer is M (mass%), the formula (3) 0.05 ≦ M / T6 ≦ 0.5 and the formula (4) 200 ≦ Ta ≦ 500 and all of formula (5) 0.3 ≦ T4 / Ta ≦ 0.5) are satisfied.

The seventeenth invention is characterized in that, in any one of the fifteenth and sixteenth inventions, the P4 layer is mainly composed of polyamide resin or polybutylene terephthalate (PBT).

In an eighteenth aspect of the invention according to any one of the sixteenth and seventeenth aspects, the main constituent is one selected from the group consisting of a low crystalline soft polymer, an acrylic adhesive, and an ethylene vinyl acetate copolymer. When the layer is a P5 layer, the P5 layer is located between the P4 layer and the P6 layer.

The nineteenth invention is a solar cell module having the solar cell backsheet according to any one of the fourteenth to eighteenth inventions.

A twentieth aspect of the invention is a method for manufacturing a back sheet for a solar cell according to the eighteenth aspect of the present invention, which is a raw material mainly comprising a polyamide resin for P4 layer or PBT, and a low crystalline soft polymer for P5 layer. A raw material mainly composed of one selected from the group consisting of an acrylic adhesive and an ethylene vinyl acetate copolymer, and a raw material mainly composed of an olefin resin for the P6 layer. A method for producing a back sheet for a solar cell, comprising: a step of feeding a P4 layer, a P5 layer, and a P6 layer after being melted together, laminating them in this order, and extruding them into a sheet form from a T-die. is there.

According to the first to thirteenth inventions, it is possible to provide a laminated sheet having excellent durability, sealing material adhesion, and interlayer adhesion that can be suitably used for a solar battery backsheet. Such a laminated sheet can be suitably used for a solar battery backsheet, and a high performance solar battery can be provided by using the backsheet.

According to the solar cell backsheets of the fourteenth to twentieth inventions, the acetic acid generated inside the solar cell module is released to the outside of the module by adjusting the acetic acid permeability and water vapor permeability of the backsheet. Thus, it is possible to prevent discoloration of the collecting electrode of the solar battery cell while maintaining the power generation characteristics for a long period of time, and by making it a more preferable form, heat resistance, P6 layer yellowing, partial discharge voltage It is possible to provide a back sheet excellent in adhesion with the sealing material.

It is sectional drawing which shows typically an example of a structure of the solar cell (solar cell module) using the lamination sheet (solar cell backsheet) of this invention. It is a jig sectional view for acetic acid permeability measurement. It is a jig top view for acetic acid permeability measurement.

The first to thirteenth inventions are laminated sheets having a layer (P1 layer) containing a polybutylene terephthalate resin as a main constituent component and a layer (P3 layer) containing a polyolefin resin as a main constituent component.

The polybutylene terephthalate resin refers to a polyester resin mainly composed of butylene terephthalate composed of terephthalate as a dicarboxylic acid component and 1,4-butanediol as a diol component. The main repeating unit here means that when all the dicarboxylic acid components in the polyester resin are 100 mol%, 80 mol% or more and 100 mol% or less are terephthalate components, and all the diol components in the polyester resin are When it is 100 mol%, it means that 80 mol% or more and 100 mol% or less is a 1,4-butanediol component. When all the dicarboxylic acid components in the polyester resin are 100 mol%, the terephthalate component is preferably 90 mol% or more and 100 mol% or less, more preferably 95 mol% or more and 100 mol%. Further, when all the diol components in the polyester resin are 100 mol%, the 1,4-butanediol component is preferably 90 mol% or more and 100 mol% or less, more preferably 95 mol% or more and 100 mol%. It is.

In such a polybutylene terephthalate resin, other components may be copolymerized in addition to terephthalic acid as the dicarboxylic acid component and 1,4-butanediol as the diol component. Specifically, as the dicarboxylic acid component, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid, eicosandioic acid, pimelic acid, azelaic acid, methylmalonic acid, ethyl Aliphatic dicarboxylic acids such as malonic acid, adamantane dicarboxylic acid, norbornene dicarboxylic acid, isosorbide, cyclohexane dicarboxylic acid, decalin dicarboxylic acid, and the like, cyclophthalic dicarboxylic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1 , 5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, 5-sodium sulfoisophthalic acid, phenylendane Dicarboxylic acid Anthracene dicarboxylic acid, phenanthrene carboxylic acid, 9,9'-bis (4-carboxyphenyl) components such as a dicarboxylic acid or its ester derivatives, such as fluorene acids and aromatic dicarboxylic acids may be copolymerized. In addition, the carboxylic acid terminal of the above-mentioned dicarboxylic acid component may be added with oxyacids such as l-lactide, d-lactide, hydroxybenzoic acid, and derivatives thereof, or a combination of a plurality of oxyacids. It is suitably used as a polymerization component. Moreover, you may use these in multiple types as needed.

Examples of the diol component include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, and 1,3-butanediol. , Cycloaliphatic diols such as cyclohexanedimethanol, spiroglycol, isosorbide, bisphenol A, 1,3-benzenedimethanol, 1,4-benzenecenemethanol, 9,9'-bis (4-hydroxyphenyl) fluorene Examples include, but are not limited to, diol components such as aromatic diols, components in which a plurality of the above-mentioned diols are linked, and the like. Moreover, you may use these in multiple types as needed.

A polybutylene terephthalate-based resin can be obtained by appropriately combining the above-mentioned dicarboxylic acid component and diol component and polycondensing them. The melting point of the resulting polybutylene terephthalate resin is generally 200 ° C. or higher and 230 ° C. or lower. Furthermore, in the present invention, it is more preferable to use one having a melting point of 215 ° C. or higher and 230 ° C. or lower.

The crystallization parameter ΔTcg of the P1 layer measured using differential scanning calorimetry (DSC) is preferably 7 to 30 ° C. If the ΔTcg of the P1 layer is less than 7 ° C., crystallization is likely to cause embrittlement, and moisture and heat resistance may decrease. If ΔTcg of the P1 layer is greater than 30 ° C., moisture may easily enter between layers due to crystallinity, and interlayer adhesion may be deteriorated. In order to set the crystallization parameter ΔTcg of the P1 layer measured using the differential scanning calorimetry (DSC) to 7 to 30 ° C., the differential scanning calorimetry (DSC) of the polybutylene terephthalate resin which is the main component of the P1 layer is used. The method of setting the crystallization parameter ΔTcg by 7) to 7-30 ° C. is preferred.

The rigid amorphous amount of the P1 layer is preferably 30 to 50%. If it is less than 30%, curling tends to occur. If it exceeds 50%, it tends to become brittle after the wet heat treatment, and the heat and humidity resistance is lowered.

Here, rigid amorphous refers to an amorphous state in which the molecular motion is frozen even at the glass transition temperature or higher in an intermediate state between the crystal and the complete amorphous. The rigid amorphous amount can be obtained from the formula: rigid amorphous amount = 100% −crystallinity−complete amorphous amount. The degree of crystallinity and the amount of complete amorphous are described in “Fiber and Industry” Vol. 65, no. 11 (2009) P.I. 428, and can be quantified using the temperature modulation DSC method. Specific measurement methods are described in the examples.

For the P1 layer, the polybutylene terephthalate resin as the main constituent component means that the polybutylene terephthalate resin is contained in an amount of more than 50% by mass and less than 100% by mass in 100% by mass of all components of the layer. means.

The P1 layer constituting the laminated sheet of the present invention preferably contains inorganic particles in the range of 0.1% by mass to 30% by mass. The content of inorganic particles in the P1 layer is more preferably 2% by mass or more and 25% by mass or less, and further preferably 5% by mass or more and 20% by mass or less. These inorganic particles are used for imparting necessary functions to the sheet depending on the purpose. When the content of the inorganic particles in the P1 layer is more than 30% by mass, handling properties may be lowered or durability may be lowered. When the content of the inorganic particles in the P1 layer is less than 0.1% by mass, the effect due to the inclusion of the inorganic particles is difficult to obtain, and yellowing may occur.

Examples of the inorganic particles suitably used for the P1 layer include inorganic particles having ultraviolet absorbing ability, particles having a large refractive index difference from the polybutylene terephthalate resin, conductive particles, and pigments. Optical properties such as ultraviolet rays, light reflectivity, and whiteness, antistatic properties, and the like can be imparted. The particle means a particle having a primary particle diameter of 5 nm or more based on the diameter of a projected equivalent equivalent circle. Unless otherwise specified, in the present invention, the particle size means a primary particle size, and the particle means a primary particle.

More specifically, the inorganic particles suitably used for the P1 layer of the present invention include, for example, gold, silver, copper, platinum, palladium, rhenium, vanadium, osmium, cobalt, iron, zinc, ruthenium, praseodymium, chromium, Metals such as nickel, aluminum, tin, zinc, titanium, tantalum, zirconium, antimony, indium, yttrium, lanthanum, zinc oxide, titanium oxide, cesium oxide, antimony oxide, tin oxide, indium tin oxide, yttrium oxide, oxidation Metal oxides such as lanthanum soot, zirconium oxide, aluminum oxide, silicon oxide, lithium fluoride, magnesium fluoride soot, aluminum fluoride soot, metal fluorides such as cryolite, metal phosphates such as calcium phosphate, carbonates such as calcium carbonate Salt, barium sulfate And sulfates such as talc, talc and kaolin.

In the present invention, in view of the fact that it is often used outdoors, as inorganic particles in the P1 layer, metal oxides such as titanium oxide, zinc oxide, and cerium oxide, which are inorganic particles having ultraviolet absorbing ability, are used. When used, it is preferable in that it can exhibit the effect of reducing coloration due to deterioration of the sheet over a long period of time by utilizing the ultraviolet resistance by the inorganic particles. Furthermore, it is more preferable to use titanium oxide as the inorganic particles in the P1 layer in that high reflection characteristics can be imparted, and it is more preferable to use rutile type titanium oxide in terms of higher ultraviolet resistance.

The method of incorporating the polybutylene terephthalate resin and inorganic particles in the P1 layer is a method in which the polybutylene terephthalate resin and inorganic particles are melt-kneaded in advance using a vent type twin-screw kneading extruder or a tandem type extruder. preferable. Here, since the thermal history is received when the inorganic particles are contained, the polybutylene terephthalate-based resin may be deteriorated. Therefore, a high-concentration master pellet with a large amount of inorganic particles is produced as compared with the amount of inorganic particles to be contained in the P1 layer, and it is mixed with a polybutylene terephthalate resin and diluted to obtain a predetermined P1 layer. Inorganic particle content is preferred from the viewpoint of durability.

As described above, it is important that the P1 layer has a polybutylene terephthalate-based resin as a main constituent, and among them, the polybutylene terephthalate-based resin that is the main constituent of the P1 layer is an end-capped polybutylene terephthalate-based resin. More preferably. Here, the end-capped polybutylene terephthalate-based resin means a resin obtained by reacting the end-capping agent with the polybutylene terephthalate-based resin.

That is, when the P1 layer is produced, a terminal blocking agent is added to the polybutylene terephthalate resin, and the carboxyl group located at the end of the polybutylene terephthalate resin (hereinafter referred to as the carboxyl group located at the terminal) It is preferable to form a P1 layer after reacting a terminal blocking agent with a terminal blocking agent to eliminate the catalytic activity of the proton of the COOH group of the polybutylene terephthalate resin. Here, the end-capping agent is a compound that reacts with and binds to the carboxyl end group of the polyester to eliminate the catalytic activity of the proton of the COOH group. Specifically, the oxazoline group, epoxy group, carbodiimide group, etc. The compound etc. which have these substituents are mentioned.

Examples of the carbodiimide compound having a carbodiimide group suitable as a terminal blocking agent include a monofunctional carbodiimide and a polyfunctional carbodiimide. Examples of monofunctional carbodiimides include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide and the like. Particularly preferred are dicyclohexylcarbodiimide and diisopropylcarbodiimide. As the polyfunctional carbodiimide, carbodiimide having a polymerization degree of 3 to 15 is preferable. Specifically, 1,5-naphthalene carbodiimide, 4,4′-diphenylmethane carbodiimide, 4,4′-diphenyldimethylmethane carbodiimide, 1,3-phenylene carbodiimide, 1,4-phenylene diisocyanate, 2,4-tolylene Carbodiimide, 2,6-tolylene carbodiimide, mixture of 2,4-tolylene carbodiimide and 2,6-tolylene carbodiimide, hexamethylene carbodiimide, cyclohexane-1,4-carbodiimide, xylylene carbodiimide, isophorone carbodiimide, isophorone carbodiimide, Dicyclohexylmethane-4,4′-carbodiimide, methylcyclohexanecarbodiimide, tetramethylxylylenecarbodiimide, 2,6-diisopropylphenylcarbodiimide, 1, , And the like can be exemplified 5- triisopropylbenzene-2,4-carbodiimide. Since a carbodiimide compound generates an isocyanate gas by thermal decomposition, a carbodiimide compound having high heat resistance is preferable. In order to improve heat resistance, it is preferable that the molecular weight (degree of polymerization) is high, and it is more preferable that the terminal of the carbodiimide compound has a structure having high heat resistance. Further, once thermal decomposition occurs, further thermal decomposition is likely to occur. Therefore, it is necessary to devise measures such as setting the extrusion temperature of polyester (polybutylene terephthalate resin) as low as possible.

Also, preferred examples of the epoxy compound suitable as the end-capping agent include glycidyl ester compounds and glycidyl ether compounds. Specific examples of the glycidyl ester compound include benzoic acid glycidyl ester, t-Bu-benzoic acid glycidyl ester, P-toluic acid glycidyl ester, cyclohexanecarboxylic acid glycidyl ester, pelargonic acid glycidyl ester, stearic acid glycidyl ester, and lauric acid glycidyl ester. , Glycidyl palmitate, glycidyl behenate, glycidyl versatate, glycidyl oleate, glycidyl linoleate, glycidyl linolein, glycidyl behenol, glycidyl stearol, diglycidyl terephthalate, isophthalic acid Diglycidyl ester, phthalic acid diglycidyl ester, naphthalenedicarboxylic acid diglycidyl ester Ter, methylterephthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, cyclohexanedicarboxylic acid diglycidyl ester, adipic acid diglycidyl ester, succinic acid diglycidyl ester, sebacic acid diglycidyl ester, dodecane Examples include diionic diglycidyl ester, octadecanedicarboxylic acid diglycidyl ester, trimellitic acid triglycidyl ester, and pyromellitic acid tetraglycidyl ester. These may be used alone or in combination of two or more. Specific examples of the glycidyl ether compound include phenyl glycidyl ether, O-phenyl glycidyl ether, 1,4-bis (β, γ-epoxypropoxy) butane, 1,6-bis (β, γ-epoxypropoxy). ) Hexane, 1,4-bis (β, γ-epoxypropoxy) benzene, 1- (β, γ-epoxypropoxy) -2-ethoxyethane, 1- (β, γ-epoxypropoxy) -2-benzyloxyethane 2,2-bis- [р- (β, γ-epoxypropoxy) phenyl] propane, 2,2-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) methane, etc. Bisglycidyl polyether obtained by the reaction of bisphenol and epichlorohydrin, and the like, and these may be used alone or in combination of two or more. Kill.

Further, as an oxazoline compound suitable as a terminal blocking agent, a bisoxazoline compound is preferable, and specifically, 2,2′-bis (2-oxazoline), 2,2′-bis (4-methyl-2-oxazoline) ), 2,2′-bis (4,4-dimethyl-2-oxazoline), 2,2′-bis (4-ethyl-2-oxazoline), 2,2′-bis (4,4′-diethyl-) 2-oxazoline), 2,2'-bis (4-propyl-2-oxazoline), 2,2'-bis (4-butyl-2-oxazoline), 2,2'-bis (4-hexyl-2- Oxazoline), 2,2'-bis (4-phenyl-2-oxazoline), 2,2'-bis (4-cyclohexyl-2-oxazoline), 2,2'-bis (4-benzyl-2-oxazoline) 2,2'-p-fu Nylenebis (2-oxazoline), 2,2'-m-phenylenebis (2-oxazoline), 2,2'-o-phenylenebis (2-oxazoline), 2,2'-p-phenylenebis (4-methyl) -2-oxazoline), 2,2'-p-phenylenebis (4,4-dimethyl-2-oxazoline), 2,2'-m-phenylenebis (4-methyl-2-oxazoline), 2,2 ' -M-phenylenebis (4,4-dimethyl-2-oxazoline), 2,2'-ethylenebis (2-oxazoline), 2,2'-tetramethylenebis (2-oxazoline), 2,2'-hexa Methylene bis (2-oxazoline), 2,2′-octamethylene bis (2-oxazoline), 2,2′-decamethylene bis (2-oxazoline), 2,2′-ethylene bis (4-methyl) 2-oxazoline), 2,2′-tetramethylenebis (4,4-dimethyl-2-oxazoline), 2,2′-9,9′-diphenoxyethanebis (2-oxazoline), 2,2 '-Cyclohexylenebis (2-oxazoline), 2,2'-diphenylenebis (2-oxazoline) and the like can be exemplified, and among these, 2,2'-bis (2-oxazoline) is Most preferred from the viewpoint of reactivity with polyester (polybutylene terephthalate resin). Furthermore, the bisoxazoline compounds listed above may be used singly or in combination of two or more as long as the object of the present invention is achieved. When a terminal blocker and a polybutylene terephthalate resin are reacted to obtain a terminal block polybutylene terephthalate resin, the concentration of the end blocker added is 0.25 to 5 with respect to 100% by mass of the polybutylene terephthalate resin. % By mass is preferable, and more preferably 0.5 to 2% by mass. If it is less than 0.25% by mass, the effect of addition is small, and there is a problem that the heat and humidity resistance is lowered. When the concentration is higher than 5% by mass, the carboxyl end groups are considerably reduced, and there is a problem that interlayer adhesion is lowered.

In addition, the P1 layer and the P3 layer of the laminated sheet of the present invention may have other additives (for example, a heat stabilizer, an ultraviolet absorber, a weather stabilizer, an organic lubricant, as long as the effects of the present invention are not impaired). Pigments, dyes, fillers, antistatic agents, nucleating agents, etc. However, the inorganic particles referred to in the present invention may not be included in the additives herein. For example, when an ultraviolet absorber is selected as an additive and contained in the P1 layer and / or the P3 layer, the ultraviolet resistance of the laminated sheet of the present invention can be further improved. Further, when an antistatic agent or the like is contained in the P1 layer and / or the P3 layer, an improvement in withstand voltage can be expected.

Further, the P1 layer preferably contains 0.1 to 5% by mass of a crystal nucleating agent. The crystal nucleating agent can be preferably selected from the group of talc, aliphatic carboxylic acid amide, aliphatic carboxylate, aliphatic alcohol, aliphatic carboxylic acid ester, sorbitol compound, and organic phosphoric acid compound. In particular, in the present invention, the crystal nucleating agent is preferably one type of crystal nucleating agent comprising an aliphatic carboxylic acid amide, an aliphatic carboxylate and a sorbitol compound. If the crystal nucleating agent is less than 0.1% by mass, the crystallinity may be low and strength may not be obtained. When it is larger than 5% by mass, the crystallinity is high and brittleness tends to occur.

Here, aliphatic carboxylic acid amides include aliphatic monocarboxylic acids such as lauric acid amide, palmitic acid amide, oleic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, ricinoleic acid amide, and hydroxy stearic acid amide. Acid amides, N-oleyl palmitic acid amide, N-oleyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl oleic acid amide, N-stearyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide N-substituted aliphatic monocarboxylic amides such as methylol behenic acid amide, methylene bis stearic acid amide, ethylene bis lauric acid amide, ethylene bis capric acid amide, ethylene bis oleic acid amide, ethylene bis Arynic acid amide, ethylene biserucic acid amide, ethylene bis behenic acid amide, ethylene bisisostearic acid amide, ethylene bishydroxystearic acid amide, butylene bisstearic acid amide, hexamethylene bisoleic acid amide, hexamethylene bisstearic acid Aliphatic biscarboxylic amides such as amide, hexamethylene bisbehenic acid amide, hexamethylene bishydroxystearic acid amide, m-xylylene bis-stearic acid amide, m-xylylene bis-12-hydroxystearic acid amide, N, N′-dioleyl sebacic acid amide, N, N′-dioleyl adipic acid amide, N, N′-distearyl adipic acid amide, N, N′-distearyl sebacic acid amide, N, N′-di Stearyl isophthalic acid amide N-substituted aliphatic carboxylic acid bisamides such as N, N'-distearyl terephthalic acid amide, N-butyl-N'-stearyl urea, N-propyl-N'-stearyl urea, N-stearyl-N'- Use N-substituted ureas such as stearyl urea, N-phenyl-N'-stearyl urea, xylylene bisstearyl urea, toluylene bisstearyl urea, hexamethylene bisstearyl urea, diphenylmethane bisstearyl urea, diphenylmethane bislauryl urea can do. These may be one kind or a mixture of two or more kinds. Of these, aliphatic monocarboxylic acid amides, N-substituted aliphatic monocarboxylic acid amides, and aliphatic biscarboxylic acid amides are preferably used, particularly palmitic acid amide, stearic acid amide, erucic acid amide, and behenic acid. Amide, ricinoleic acid amide, hydroxystearic acid amide, N-oleyl palmitic acid amide, N-stearyl erucic acid amide, ethylene biscapric acid amide, ethylene bisoleic acid amide, ethylene bislauric acid amide, ethylene biserucic acid amide, m -Xylylene bis-stearic acid amide and m-xylylene bis-12-hydroxystearic acid amide are preferably used.

Specific examples of the aliphatic carboxylate include acetates such as sodium acetate, potassium acetate, magnesium acetate, calcium acetate, sodium laurate, potassium laurate, potassium hydrogen laurate, magnesium laurate, calcium laurate, zinc laurate , Laurates such as silver laurate, lithium myristate, sodium myristate, potassium hydrogen myristate, magnesium myristate, calcium myristate, zinc myristate, silver myristate, myristate, lithium palmitate, palmitic acid Palmitates such as potassium, magnesium palmitate, calcium palmitate, zinc palmitate, copper palmitate, lead palmitate, thallium palmitate, cobalt palmitate, etc., sodium oleate Oleates such as potassium oleate, magnesium oleate, calcium oleate, zinc oleate, lead oleate, thallium oleate, copper oleate, nickel oleate, sodium stearate, lithium stearate, magnesium stearate, Stearates such as calcium stearate, barium stearate, aluminum stearate, thallium stearate, lead stearate, nickel stearate, beryllium stearate, sodium isostearate, potassium isostearate, magnesium isostearate, calcium isostearate, isostearic acid Isostearates such as barium, aluminum isostearate, zinc isostearate, nickel isostearate, sodium behenate Behenates such as lithium, potassium behenate, magnesium behenate, calcium behenate, barium behenate, aluminum behenate, zinc behenate, nickel behenate, sodium montanate, potassium montanate, magnesium montanate, calcium montanate Further, montanates such as barium montanate, aluminum montanate, zinc montanate and nickel montanate can be used. These may be one kind or a mixture of two or more kinds. In particular, stearic acid salts and montanic acid salts are preferably used, and in particular, sodium stearate, potassium stearate, zinc stearate, barium stearate, sodium montanate, and the like are suitably used.

Specific examples of aliphatic alcohols include aliphatic monoalcohols such as pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, nonadecyl alcohol, eicosyl alcohol, seryl alcohol, and melyl alcohol, 1,6-hexane. Diols, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, aliphatic polyhydric alcohols such as 1,10-decanediol, cyclopentane-1,2-diol, cyclohexane-1 , 2-diols, cyclic alcohols such as cyclohexane-1,4-diol, and the like can be used. These may be one kind or a mixture of two or more kinds. In particular, aliphatic monoalcohols are preferably used, and stearyl alcohol is particularly preferably used.

Specific examples of the aliphatic carboxylic acid ester include lauric acid cetyl ester, lauric acid phenacyl ester, myristic acid cetyl ester, myristic acid phenacyl ester, palmitic acid isopropylidene ester, palmitic acid dodecyl ester, and palmitic acid tetraethyl ester. Aliphatic monocarboxylic acid esters such as dodecyl ester, palmitic acid pentadecyl ester, palmitic acid octadecyl ester, palmitic acid cetyl ester, palmitic acid phenyl ester, palmitic acid phenacyl ester, stearic acid cetyl ester, behenic acid ethyl ester, monolaurin Monoesters of ethylene glycol such as acid glycol, glycol monopalmitate, glycol monostearate, glycol dilaurate, Diesters of ethylene glycol such as glycol palmitate and glycol distearate, monolaurate glycerin ester, monomyristic acid glycerin ester, monopalmitic acid glycerin ester, glycerin monoesters such as monostearic acid glycerin ester, dilauric acid glycerin ester, Glycerin diesters such as dimyristic acid glycerin ester, dipalmitic acid glycerin ester, distearic acid glycerin ester, trilauric acid glycerin ester, trimyristic acid glycerin ester, tripalmic acid glycerin ester, tristearic acid glycerin ester, palmitodiolein, Use glycerin triesters such as palmitodistearin and oleodistearin. Door can be. These may be one kind or a mixture of two or more kinds.

Specific examples of such aliphatic / aromatic carboxylic acid hydrazides include sebacic acid dibenzoic acid hydrazide, specific examples of melamine compounds, specific examples of melamine cyanurate, polymelate melamine, and phenylphosphonic acid metal salts. For example, phenylphosphonic acid zinc salt, phenylphosphonic acid calcium salt, phenylphosphonic acid magnesium salt, and phenylphosphonic acid magnesium salt can be used.

Examples of sorbitol compounds include 1,3-di (P-methylbenzylidene) sorbitol, 2,4-di (P-methylbenzylidene) sorbitol, 1,3-dibenzylidenesorbitol, 2,4-dibenzylidenesorbitol, Examples include 3-di (P-ethyldibenzylidene) sorbitol and 2,4-di (P-ethyldibenzylidene) sorbitol.

Examples of the organic phosphate compound include sodium bis (4-t-butylphenyl) phosphate,

sodium

2,2′-methylenebis (4,6-di-t-butylphenyl) phosphate, and cyclic organic phosphate ester Examples thereof include a mixture selected from basic polyvalent metal salts and alkali metal carboxylates, alkali metal β-diketonates and alkali metal β-ketoacetate organic carboxylic acid metal salts.

Among the above, sodium montanate is preferably used from the viewpoint of strength.

In the present invention, it is preferable to have a layer (P2 layer) mainly composed of an adhesive polyolefin-based resin, and further, the P1 layer and a P3 layer described later are in contact with each other via the P2 layer. Here, the P1 layer and the P3 layer are in contact with each other via the P2 layer means that the P1 layer, the P2 layer, and the P3 layer are directly laminated in this order.

The adhesive polyolefin-based resin means one selected from the group consisting of a low crystalline soft polymer, an acrylic adhesive, and an ethylene vinyl acetate-based copolymer. The layer (P2 layer) is a layer mainly composed of one selected from the group consisting of a low crystalline soft polymer, an acrylic adhesive, and an ethylene vinyl acetate copolymer. In addition, regarding the P2 layer, the main constituent component is one selected from the group consisting of a low crystalline soft polymer, an acrylic adhesive, and an ethylene vinyl acetate copolymer. It means that one selected from the group consisting of a low crystalline soft polymer, an acrylic adhesive, and an ethylene vinyl acetate copolymer exceeds 50% by mass and is equal to or less than 100% by mass.

Examples of the low crystalline soft polymer that is one of the main components of the P2 layer include acid-modified polyolefins and unsaturated polyolefins. Examples of the acrylic adhesive that is one of the main components of the P2 layer include ethylene-acrylic acid ester-maleic anhydride terpolymer. Among these, from the viewpoint of adhering to both the P1 layer and the P3 layer, the P2 layer is preferably made of acid-modified polyolefin as a main constituent. Examples of the acid-modified polyolefin include “Admer” manufactured by Mitsui Chemicals, Inc., “Modic” manufactured by Mitsubishi Chemical, and “Binnel” manufactured by DuPont.

The P2 layer preferably further contains a polyolefin elastomer in addition to the adhesive polyolefin resin. The polyolefin-based elastomer generally refers to one obtained by finely dispersing ethylene-propylene rubber in polypropylene or one obtained by copolymerizing polypropylene with another α-olefin. These polyolefin-based elastomers are preferably contained in a proportion of 0.1% by mass or more and 20% by mass or less with respect to 100% by mass of all components of the P2 layer. By including the polyolefin-based elastomer, it is possible to impart adhesiveness to the P2 layer, and the adhesion between the P1 layer and the P2 layer and the adhesion between the P1 layer and the P2 layer are improved. The content of the polyolefin-based elastomer in the P2 layer is preferably 5% by mass or more and 20% by mass or less. The polyolefin-based elastomer may be a commercially available product, for example, “Thermolan”, “Zeras” manufactured by Mitsubishi Chemical Corporation, “Excellen”, “Tough Selenium”, “Esplen”, “Hibler” manufactured by Kuraray, Preferred examples include “Septon” and “Notio” manufactured by Mitsui Chemicals.

The P3 layer in the present invention is a layer mainly composed of a polyolefin-based resin. Examples of the polyolefin resin in the present invention include polyethylene, polypropylene, polybutene, polymethylpentene, polycycloolefin, polyhexene, polyoctene, polydecene, and polydodecene. Here, the adhesive polyolefin resin that is the main constituent of the P2 layer does not correspond to the polyolefin resin that is the main constituent of the P3 layer. Among these, since the processing is easy and relatively inexpensive, the polyolefin resin that is the main component of the P3 layer is preferably polyethylene or polypropylene. These polyolefin-based resins may be mixed and copolymerized with other olefin components. For example, when an ethylene-propylene copolymer or ethylene-propylene-butene copolymer is used, the melting point of the resin can be lowered, and adhesion with a sealing material can be reduced. It is preferable because of improved properties.

For the P3 layer, the main component of polyolefin resin means that 100% by mass of the total component of the layer contains more than 50% by mass and 100% by mass or less of polyolefin resin.

The P3 layer constituting the laminated sheet of the present invention preferably contains inorganic particles in the range of 0.1% by mass to 30% by mass. The content of inorganic particles in the P3 layer is more preferably 2% by mass or more and 25% by mass or less, and further preferably 5% by mass or more and 20% by mass or less. These inorganic particles are used for imparting necessary functions to the sheet depending on the purpose. When the content of the inorganic particles in the P3 layer is more than 30% by mass, the adhesion with the sealing material may be lowered. When the content of the inorganic particles in the P3 layer is less than 0.1% by mass, it is difficult to obtain the effect due to the inclusion of the inorganic particles, and yellowing may occur.

Further, it is preferable that the P3 layer contains 5 to 30% by mass of inorganic particles having a particle diameter of 3 μm or more and 20 μm or less. Here, the particle size refers to an average particle size at an integrated value of 50% in a particle size distribution obtained by laser analysis / scattering method. If the inorganic particles having a size of 3 μm or more and 20 μm or less are less than 5% by mass, the mechanical strength may be reduced. If the inorganic particles having a size of 3 μm or more and 20 μm or less are larger than 30% by mass, the surface may be roughened and the adhesion with the sealant may be lowered. The P3 layer preferably contains 0.5 to 5% by mass of an adhesive polyolefin resin. The adhesive polyolefin-based resin may act as a dispersion aid for inorganic particles having a size of 3 μm or more and 20 μm or less. If it is less than 0.5% by mass, the mechanical strength may decrease due to poor dispersion of the inorganic particles of 3 μm or more and 20 μm or less. If it is larger than 5% by mass, the heat resistance may decrease. The adhesive polyolefin resin here is the same as that defined for the P2 layer adhesive polyolefin resin.

The acetic acid permeability Pa (g / m ² / day) in the laminated sheet of the present invention means the acetic acid permeability when acetic acid is in a saturated vapor pressure state (85 ° C.). And as for the lamination sheet of this invention, it is preferable that the acetic acid permeability Pa in 85 degreeC satisfy | fills the following formula | equation (1).
(1) 200 ≦ Pa
When the laminated sheet of the present invention is used as a back sheet, it is important that the acetic acid generated from the encapsulant positively escapes from the back sheet before it affects the solar cells. From the viewpoint of suppressing the decrease in power generation performance, it is important that the laminated sheet of the present invention has an acetic acid permeability Pa of 200 g / m ² / day or more. Moreover, from the viewpoint of further suppressing power generation performance degradation, the acetic acid permeability Pa of the laminated sheet of the present invention is preferably 800 g / m ² / day or more. On the other hand, the acetic acid permeability Pa is preferably as large as possible. However, considering that not only the expression (1) but also the expression (2) regarding the water vapor permeability Pw described later is satisfied at the same time, the acetic acid permeability Pa is 1500 g / m ² / day. The following is preferable.

The water vapor transmission rate Pw (g / m ² / day) in the laminated sheet of the present invention means the water vapor transmission rate in an environment of 40 ° C. and 90% RH. And as for the laminated sheet of this invention, it is preferable that the water-vapor-permeation rate Pw (g / m < ² > / day) in 40 degreeC90% RH satisfy | fills the following formula | equation (2).
(2) Pw ≦ 2.5
In the laminated sheet of the present invention, the water vapor permeability Pw of the laminated sheet of the present invention is 2.5 g / in, from the viewpoint of suppressing corrosion inside the solar cell module due to moisture, particularly discoloration due to corrosion of the collecting electrode portion of the solar battery cell. It is preferably m ² / day or less. Moreover, it is preferable that it is 2.0 g / m < ² > / day or less from a viewpoint of discoloration suppression of the current collection electrode of the further cell. On the other hand, the water vapor transmission rate Pw is preferably as small as possible. However, considering not only the equation (2) but also the equation (1) relating to the acetic acid transmission rate Pa described above, the water vapor transmission rate Pw is 0.5 g / m. ² / day or more is preferable.

The thickness of the P1 layer constituting the laminated sheet of the present invention is preferably 80 μm or more. If it is less than 80 μm, the heat resistance may decrease. The thickness of the P2 layer constituting the laminated sheet of the present invention is preferably 15 μm or more and 50 μm or less. If it is less than 15 μm, the adhesion between the layers may be lowered. When the thickness of the P2 layer is larger than 50 μm, the heat resistance may be lowered. The thickness of the P3 layer constituting the laminated sheet of the present invention is preferably 50 μm or more. If it is less than 50 micrometers, adhesiveness with a sealing material may fall.

It is important that the laminated sheet of the present invention has a P1 layer and a P3 layer. And the laminated structure of the laminated sheet in the present invention is preferably a structure in which at least the P1 layer is located on the surface layer and the P3 layer is located on the opposite surface layer to the P1 layer. Here, the P1 layer is located on the reverse surface layer of the P1 layer means that the P1 layer is located on one outermost layer of the laminated sheet and the P3 layer is located on the other outermost layer.

Also, the laminated sheet of the present invention can be a laminated body laminated with another film or the like. Also in such a laminated body, it is preferable that the P1 layer has a laminated structure provided on any one of the surface layers. Examples of other films include polyester layers for increasing mechanical strength, antistatic layers, adhesion layers with other materials, UV resistant layers for further improving UV resistance, and flame resistance for imparting flame resistance A layer, a hard coat layer for improving impact resistance and scratch resistance, and the like can be arbitrarily selected and used depending on applications. As a specific example when the laminated sheet of the present invention is a laminated body laminated with another film or the like, when the laminated sheet of the present invention is used as a solar battery backsheet, other sheet materials or power generation elements are embedded. In order to further improve the adhesion to the sealing material (for example, ethylene vinyl acetate), in addition to the easy adhesion layer, UV-resistant layer, flame retardant layer, the voltage at which partial discharge phenomenon, which is an index of insulation, is generated is improved. For example, a conductive layer to be formed may be formed.

Next, an example is given and demonstrated about the manufacturing method of the lamination sheet of the present invention. Examples of the method for laminating the P1 layer, P2 layer, and P3 layer in the laminated sheet of the present invention include, for example, a raw material for the P1 layer mainly composed of polybutylene terephthalate resin and a main component composed of an adhesive polyolefin resin. The raw material for P2 layer and the raw material for P3 layer mainly composed of polyolefin resin are supplied to different extruders, and after melting, P1 layer, P2 layer and P3 layer are merged in this order and laminated Then, a method of processing into a sheet including a step of extruding from a T die into a sheet (coextrusion method), laminating a raw material of a coating layer into a sheet produced by a single film, putting it into an extruder, melting and extruding from a die Method (melt laminating method), each film is prepared separately and thermocompression-bonded by a heated roll group (thermal laminating method), adhesive The method of bonding through (adhesion method), other methods of applying and drying the one dissolved in a solvent (coating method), and can be used a method in which a combination of these. Of these, the coextrusion method is preferred in that the production process is short and the adhesion between the layers is good. Hereafter, the manufacturing method by a coextrusion method is explained in full detail.

When the laminated sheet of the present invention is produced by a coextrusion method, first, a raw material for the P1 layer having a dried polybutylene terephthalate resin as a main constituent, a raw material for a P2 layer having an adhesive polyolefin resin as a main constituent, And three raw materials for P3 layer, the main component of which is polyolefin resin and polyolefin resin, heated to 240 ° C to 300 ° C, P2 layer and P3 layer to 180 ° C to 250 ° C under nitrogen flow Each is fed to an extruder and melted. Next, using a multi-manifold die, a feed block, a static mixer, a pinol, etc., the P1 layer, the P2 layer and the P3 layer are joined and laminated in this order, and are coextruded from the T die into a sheet. When the difference in melt viscosity of each layer is large, it is preferable to use a multi-manifold die from the viewpoint of suppressing lamination unevenness.

The laminated sheet of the present invention can be obtained by extruding the laminated sheet discharged from the T die by the above-described method onto a cooling body such as a casting drum and cooling and solidifying it.

The laminated sheet of the present invention obtained by the above-described method may be subjected to processing such as heat treatment or aging as necessary within the range where the effects of the present invention are not impaired. By heat-treating, the thermal dimensional stability of the laminated sheet of the present invention can be improved. Moreover, in order to improve the adhesiveness of the laminated sheet of the present invention obtained by the above method, corona treatment or plasma treatment may be performed.

The solar cell backsheet of the present invention is composed of the laminated sheet of the present invention. That is, the laminated sheet of the present invention can be suitably used as a solar battery back sheet. The solar cell of the present invention is characterized by using the solar cell backsheet of the present invention. By using the laminated sheet of the present invention in a solar cell, it becomes possible to increase the durability or reduce the thickness as compared with a conventional solar cell. A structural example of the solar cell of the present invention is shown in FIG. In FIG. 1, a power generating element connected with a lead wire for taking out electricity (not shown in FIG. 1) is sealed with a transparent sealing material 2 such as EVA resin, and a transparent substrate 4 such as glass and the like. Although the laminated sheet of the present invention is configured to be bonded as the solar battery backsheet 1, the configuration example of the solar battery of the present invention is not limited to this, and can be used for any configuration. In addition, although the example by the lamination sheet single-piece | unit of this invention was shown in FIG. 1, it is also possible to use the composite sheet of the lamination sheet of this invention and another film according to the other required required characteristic.

In the laminated sheet of the present invention, as a method of laminating with other films, etc., for example, a method of co-extrusion and processing into a sheet (co-extrusion method), a coating layer raw material is put into an extruder into a sheet made of a single film Then, melt extrusion and laminating while extruding from the die (melt laminating method), making each film separately, thermocompression bonding with heated rolls etc. (thermal laminating method), pasting through adhesive A method of bonding (adhesion method), a method of applying and drying a solution dissolved in a solvent (coating method), a method of combining these, and the like can be used.

In the solar cell of the present invention, the above-described solar cell backsheet 1 is installed on the back surface of the sealing material 2 in which the power generating element is sealed. Here, the solar cell backsheet of the present invention has an asymmetric configuration, and the P3 layer is disposed so as to be positioned on the sealing material 2 side, so that the adhesion with the sealing material can be further increased. This is preferable. Moreover, since it becomes the structure arrange | positioned so that P1 layer of the lamination sheet of this invention may be located in the opposite side to the sealing material 2, it becomes possible to improve the tolerance with respect to the ultraviolet rays etc. of the reflection from the ground, and high durability. It can be a solar cell or the thickness can be reduced.

The power generating element 3 converts light energy of sunlight into electric energy, and is based on crystalline silicon, polycrystalline silicon, microcrystalline silicon, amorphous silicon, copper indium selenide, compound semiconductor, dye enhancement Arbitrary elements such as a sensitive system can be used in series or in parallel according to the desired voltage or current depending on the purpose. Since the transparent substrate 4 having translucency is located on the outermost surface layer of the solar cell, a transparent material having high weather resistance, high contamination resistance, and high mechanical strength characteristics in addition to high transmittance is used. In the solar cell of the present invention, the transparent substrate 4 having translucency can be made of any material as long as the above characteristics are satisfied. Examples thereof include glass, ethylene tetrafluoride-ethylene copolymer (ETFE), polyfluoride. Vinyl fluoride resin (PVF), polyvinylidene fluoride resin (PVDF), polytetrafluoroethylene resin (TFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polytrifluoroethylene chloride resin (CTFE) ), Fluorinated resins such as polyvinylidene fluoride resins, polyolefin resins, acrylic resins, and mixtures thereof. In the case of glass, it is more preferable to use a tempered glass. Moreover, when using the resin-made translucent base material, what extended | stretched the said resin uniaxially or biaxially from a viewpoint of mechanical strength is used preferably.

In addition, in order to provide these substrates with adhesion to an EVA resin or the like that is a sealing material for power generation elements, it is preferable to subject the surface to corona treatment, plasma treatment, ozone treatment, and easy adhesion treatment. Is called.

The sealing material 2 for sealing the power generating element covers the surface of the power generating element with resin and fixes it, protects the power generating element from the external environment, and has a light-transmitting base material for the purpose of electrical insulation. In addition, a material having high transparency, high weather resistance, high adhesion, and high heat resistance is used to adhere to the backsheet and the power generation element. Examples thereof include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA) resin, ethylene-methacrylic acid copolymer (EMAA), Ionomer resins, polyvinyl butyral resins, and mixtures thereof are preferably used.

As described above, by incorporating the solar battery back sheet using the laminated sheet of the present invention into the solar battery, it becomes possible to obtain a highly durable and / or thin solar battery compared to the conventional solar battery. . The solar cell of the present invention can be suitably used for various applications without being limited to outdoor use and indoor use such as a solar power generation system and a power source for small electronic components.

Next, embodiments of the solar cell backsheet, the manufacturing method thereof, and the solar cell module according to the fourteenth to twentieth inventions will be described. In addition, this form is only concretely described in order to make the gist of the invention better understood, and the present invention is not limited to this form.

The acetic acid permeability Pa (g / m ² / day) in the backsheet of the present invention means the acetic acid permeability when acetic acid is in a saturated vapor pressure state (85 ° C.). And it is important for the back seat | sheet of this invention that the acetic acid permeability Pa in 85 degreeC satisfy | fills the following formula | equation (1).
(1) 200 ≦ Pa
In the backsheet of the present invention, it is important that the acetic acid generated from the encapsulant is positively removed from the backsheet before it affects the solar battery cells, from the viewpoint of suppressing power generation performance degradation during the constant temperature and humidity test. It is important that the acetic acid permeability Pa of the backsheet of the present invention is 200 g / m ² / day or more. Further, from the viewpoint of further suppressing power generation performance degradation, the acetic acid permeability Pa of the backsheet of the present invention is preferably 800 g / m ² / day or more. On the other hand, the acetic acid permeability Pa is preferably as large as possible. However, considering that not only the expression (1) but also the expression (2) regarding the water vapor permeability Pw described later is satisfied at the same time, the acetic acid permeability Pa is 1500 g / m ² / day. The following is preferable.

The water vapor transmission rate Pw (g / m ² / day) in the backsheet of the present invention means the water vapor transmission rate in an environment of 40 ° C. and 90% RH. In the back sheet of the present invention, it is important that the water vapor transmission rate Pw (g / m ² / day) at 40 ° C. and 90% RH satisfies the following formula (2).
(2) Pw ≦ 2.5
The backsheet of the present invention has a water vapor transmission rate Pw of 2.5 g / in from the viewpoint of suppressing corrosion inside the solar cell module due to moisture, particularly discoloration due to corrosion of the collector electrode portion of the solar battery cell. It is important that it is not more than m ² / day. Moreover, it is preferable that it is 2.0 g / m < ² > / day or less from a viewpoint of discoloration suppression of the current collection electrode of the further cell. On the other hand, the water vapor transmission rate Pw is preferably as small as possible. However, considering not only the equation (2) but also the equation (1) relating to the acetic acid transmission rate Pa described above, the water vapor transmission rate Pw is 0.5 g / m. ² / day or more is preferable.

In order that the acetic acid permeability Pa of the back sheet satisfies the formula (1) and the water vapor permeability Pw satisfies the formula (2) at the same time, it is preferable that the back sheet has a P4 layer. Here, the P4 layer means a layer in which one selected from the group consisting of a polyester resin, a polyamide resin, and a fluororesin is a main constituent component. In addition, the layer which is one main component selected from the group consisting of a polyester resin, a polyamide resin, and a fluororesin is one layer selected from the group consisting of a polyester resin, a polyamide resin, and a fluororesin. Means a layer containing more than 50% by mass and 100% by mass or less in 100% by mass of all components.

The polyester resin suitably used as the main component of the P4 layer in the present invention is a resin obtained by polycondensation of dicarboxylic acid and dialcohol. This polyester resin can be used alone or in combination with other resins.

Specific examples of the dicarboxylic acid used for obtaining the polyester resin include terephthalic acid and 2,6-naphthalenedicarboxylic acid.

Further, specific examples of dialcohol used for obtaining a polyester resin include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and the like.

Among these, as the polyester resin, polyethylene terephthalate and / or polybutylene terephthalate are preferable from the viewpoints of price, water vapor permeability, strength, heat resistance, and the like.

The polyamide resin suitably used as the main component of the P4 layer in the present invention is 1) a ring-opening polymerization of a compound having a lactam skeleton, and 2) an amino acid component having an amino group and a carboxyl group in one molecule. Condensed ones, 3) polycondensed diamine components and dicarboxylic acid components, and those obtained by copolymerizing 1) to 3). The polyamide resin can be used alone or in combination with other resins.

Examples of the compound having a lactam skeleton used in 1) include ε-caprolactam (nylon 6 is obtained by ring-opening polymerization), ω-undecanlactam (nylon 11 is obtained by ring-opening polymerization), and ω-laurolactam. And lactam compounds such as (Nylon 12 is obtained by ring-opening polymerization).

Examples of the amino acid component having an amino group and a carboxyl group in one molecule used in 2) include amino acids such as ε-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

The diamine component used in 3) includes tetramethylene diamine, hexamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 1,2,2,4-tetramethylhexamethylene diamine, 2,4,4-trimethyl. Hexamethylenediamine, 5-methylnonamethylenediamine, m-xylylenediamine, p-xylylenediamine, 1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, bis-p-aminocyclohexylmethane, Examples include 2,2-bis-p-aminocyclohexylpropane and isophoronediamine. Examples of the dicarboxylic acid component used in 3) include adipic acid, peric acid, azelaic acid, sepacic acid, dodecanoic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, Examples thereof include dicarboxylic acids such as naphthalenedicarboxylic acid and dimer acid.

These components are subjected to polymerization in the form of 1) a compound having a lactam skeleton, 2) an amino acid component alone, or a mixture of amino acid components, or 3) a mixture of diamine and dicarboxylic acid, and thus obtained. As the polyamide resin, any one of a polymer of the component alone or a copolymer containing two or more components can be used in the present invention. Among these, as the polyamide resin used as the main component of the P4 layer, polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 610), polyhexa Methylene dodecanamide (nylon 612), polyhexamethylene terephthalamide (nylon 6T), polyhexamethylene isophthalamide (nylon 6I), polyundecanamide (nylon 11), and polydodecanamide (nylon 12) are preferred.

Further, in the backsheet of the present invention, the polyamide resin suitably used as the main constituent component of the P4 layer is nylon 6, nylon 66, nylon 610, nylon 11, in terms of crystallinity, strength, heat resistance and rigidity. And at least one resin selected from the group consisting of nylon 12 and nylon 12.

The fluororesin suitably used as the main component of the P4 layer in the present invention is 1) a polymer obtained by substituting some or all of the hydrocarbon atoms with fluorine atoms, and 2) one hydrocarbon. A copolymer of a part or all of the hydrogen atoms substituted with fluorine atoms and a copolymer with a hydrocarbon; 3) a part or all of the hydrogen atoms of a hydrocarbon substituted with fluorine atoms; Copolymers in which part or all of the hydrogen atoms are substituted with fluorine atoms, 4) Polymers of 1) to 3), or copolymers, wherein some of the hydrogen atoms or fluorine atoms are chlorine atoms And a polymer or copolymer in which at least one fluorine atom is present after substitution with a chlorine atom.

Examples of such fluororesins include polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, polychlorotrifluoroethylene, And ethylene / chlorotrifluoroethylene copolymer. From the viewpoints of price, water vapor permeability, and acetic acid permeability, the fluororesin suitably used as the main component of the P4 layer in the backsheet of the present invention is polyvinyl fluoride, polyvinylidene fluoride, ethylene tetrafluoroethylene, four A fluorinated ethylene / hexafluoropropylene copolymer is particularly preferred.

As described so far, the P4 layer is a layer mainly composed of one selected from the group consisting of a polyester resin, a polyamide resin, and a fluororesin, but the P4 layer is made of a polyamide resin or polybutylene terephthalate. It is particularly preferable to use the main component.

When the back sheet of the present invention has a P4 layer, the P4 layer preferably contains 0.1% by mass to 30% by mass of inorganic particles in 100% by mass of all components of the P4 layer. The content of the inorganic particles in the P4 layer is more preferably 2% by mass or more and 25% by mass or less, and further preferably 5% by mass or more and 20% by mass or less. The inorganic particles are used for imparting necessary functions to the back sheet depending on the purpose. When the content of the inorganic particles in the P4 layer exceeds 30% by mass, handling properties may be lowered or durability may be lowered. When the content of the inorganic particles in the P4 layer is less than 0.1% by mass, the effect due to the inclusion of the inorganic particles is difficult to obtain, and yellowing may occur.

Examples of inorganic particles suitable for use in the P4 layer include inorganic particles having ultraviolet absorbing ability, particles having a large refractive index difference from polyester resins, polyamide resins, and fluororesins, conductive particles, and pigments. Thus, it is possible to impart ultraviolet resistance, optical properties such as light reflectivity and whiteness, antistatic properties and the like. In the present invention, the particle means a particle having a primary particle diameter of 5 nm or more based on the diameter of a projected equivalent equivalent circle. Unless otherwise specified, in the present invention, the particle size means a primary particle size, and the particle means a primary particle.

More specifically, the inorganic particles suitably used for the P4 layer of the present invention include, for example, gold, silver, copper, platinum, palladium, rhenium, vanadium, osmium, cobalt, iron, zinc, ruthenium, praseodymium, chromium, Metals such as nickel, aluminum, tin, zinc, titanium, tantalum, zirconium, antimony, indium, yttrium, lanthanum, zinc oxide, titanium oxide, cesium oxide, antimony oxide, tin oxide, indium tin oxide, yttrium oxide, oxidation Metal oxides such as lanthanum soot, zirconium oxide, aluminum oxide, silicon oxide, lithium fluoride, magnesium fluoride soot, aluminum fluoride soot, metal fluorides such as cryolite, metal phosphates such as calcium phosphate, carbonates such as calcium carbonate Salt, barium sulfate And sulfates such as talc, talc and kaolin.

In the present invention, in view of the fact that it is often used outdoors, metal oxides such as titanium oxide, zinc oxide, and cerium oxide, which are inorganic particles having ultraviolet absorbing ability, are used as the inorganic particles in the P4 layer. In this case, it is preferable in that the effect of reducing coloring due to deterioration of the back sheet can be exhibited over a long period by utilizing the ultraviolet resistance by the inorganic particles. Furthermore, it is more preferable to use titanium oxide as the inorganic particles in the P4 layer in that high reflection characteristics can be imparted, and it is more preferable to use rutile type titanium oxide in terms of higher ultraviolet resistance.

In the method of including polyester resin, polyamide resin, fluororesin or inorganic particles in the P4 layer, the resin and inorganic particles are melt kneaded in advance using a vent type biaxial kneading extruder or tandem type extruder. The method is preferred. Here, since the thermal history is received when the inorganic particles are contained, the resin may be deteriorated. Therefore, compared to the amount of inorganic particles to be included in the P4 layer, a high-concentration master pellet having a large amount of inorganic particles is prepared, mixed with the resin and diluted, and the predetermined P4 layer contains inorganic particles. It is preferable to set the ratio from the viewpoint of durability.

The P4 layer and the P6 layer of the backsheet of the present invention (P6 layer will be described later) may have other additives (for example, a heat stabilizer, an ultraviolet absorber, Examples include weathering stabilizers, organic lubricants, pigments, dyes, fillers, antistatic agents, nucleating agents, etc. However, the inorganic particles referred to in the present invention are not included in the additive herein. You may do it. For example, when an ultraviolet absorber is selected as an additive and contained in the P4 layer and / or the P6 layer, the ultraviolet resistance of the backsheet of the present invention can be further improved. Further, when an antistatic agent or the like is contained in the P4 layer and / or the P6 layer, an improvement in withstand voltage can be expected.

Further, it is important that the P4 layer in the present invention is located on the surface layer of the back sheet from the viewpoint of flame retardancy. Here, the P4 layer being positioned on the surface means that the P4 layer is positioned on one outermost layer of the backsheet of the present invention.

In the present invention, the P5 layer is preferably located between the P4 layer and the P6 layer described later. Here, the P5 layer is a layer mainly composed of one selected from the group consisting of a low crystalline soft polymer, an acrylic adhesive, and an ethylene vinyl acetate copolymer. In addition, regarding the P5 layer, the main constituent is one selected from the group consisting of a low crystalline soft polymer, an acrylic adhesive, and an ethylene vinyl acetate copolymer. It means that one selected from the group consisting of a crystalline soft polymer, an acrylic adhesive, and an ethylene vinyl acetate copolymer is contained more than 50% by mass and 100% by mass or less.

The P5 layer is preferably located between the P4 layer and the P6 layer. When the P5 layer is located between the P4 layer and the P6 layer, for example, in the backsheet of the present invention, the P4 layer is located on the surface layer, and when the P6 layer is located on the surface opposite to the P4 layer, It means that the P5 layer is located in the inner layer between these two layers.

The P5 layer preferably has a function of adhering to both the P4 layer and the P6 layer. The low crystalline soft polymer that is one of the main components of the P5 layer preferably has a crystallinity of 50% or less and a melting point of 170 ° C. or less. For example, an acid-modified olefin, an unsaturated polyolefin, etc. Can be mentioned. Examples of the acrylic adhesive that is one of the main components of the P5 layer include an ethylene-acrylic ester-maleic anhydride terpolymer. In particular, from the viewpoint of adhering to both the P4 layer and the P6 layer, the P5 layer is preferably composed of acid-modified polyolefin as a main constituent. Examples of the acid-modified polyolefin include “Admer” (registered trademark) manufactured by Mitsui Chemicals, Inc. and “Modic” (registered trademark) manufactured by Mitsubishi Chemical Corporation.

The layer in which the olefin resin is the main constituent is designated as P6 layer. Examples of the olefin resin used in the P6 layer include polyethylene, polypropylene, polybutene, polymethylpentene, polycycloolefin, polyhexene, polyoctene, polydecene, and polydodecene. Among these, since it is easy to process and is relatively inexpensive, the olefin resin that is the main component of the P6 layer is preferably polyethylene or polypropylene. These olefin resins may be mixed and copolymerized with other olefin components. For example, when an ethylene-propylene copolymer or an ethylene-propylene-butene copolymer is used, the melting point of the resin can be lowered.

In addition, about P6 layer, that an olefin resin is a main component means that 100 mass% of olefin resin is contained more than 50 mass% in 100 mass% of all the components of this layer.

The melting point (hereinafter also referred to as melting endothermic peak temperature) of the olefin resin that is the main component of the P6 layer in the present invention is preferably 120 ° C. or higher and 170 ° C. or lower. If the melting point of the olefin resin in the P6 layer is less than 120 ° C, the heat resistance may be inferior. On the other hand, when the melting point of the olefin resin in the P6 layer exceeds 170 ° C., the adhesiveness with the sealing material may be lowered.

The backsheet of the present invention preferably has a P4 layer and a P6 layer, the P6 layer contains inorganic particles, the P4 layer is located on the surface layer, and the P6 layer is located on the surface opposite to the P4 layer. Further, the back sheet of the present invention has a total thickness of Ta (μm), a thickness of the P4 layer of T4 (μm), a thickness of the P6 layer of T6 (μm), and the content of inorganic particles in the P6 layer. It is more preferable that all of the formulas (3) to (5) are satisfied when M (mass%) is used.
(3) 0.05 ≦ M / T6 ≦ 0.5
(4) 200 ≦ Ta ≦ 500
(5) 0.3 ≦ T4 / Ta ≦ 0.5
By simultaneously satisfying the formulas (3) to (5), a back sheet having both heat resistance, sealing material adhesion, water vapor permeability, and electrical characteristics can be obtained.

In addition, when the back sheet of the present invention has a plurality of P4 layers and P6 layers, T4 is obtained using only the P4 layer of the surface layer, T6 and M are obtained using only the P6 layer of the reverse surface layer, It is important that this satisfies the equations (3) to (5) at the same time.

Formula (3) formulates the amount of inorganic particles per thickness, and in order to express the effect of inorganic particles, it is important to increase the concentration of inorganic particles as the thickness increases. Show. In Formula (3), when M / T6 is smaller than 0.05, the P6 layer is easily yellowed due to deterioration. If M / T6 is greater than 0.5, the adhesion to EVA may be reduced.

The P6 layer preferably contains inorganic particles. The inorganic particles in the P6 layer are used for imparting necessary functions to the back sheet depending on the purpose. As the inorganic particles in the P6 layer, the same inorganic particles as those mentioned as the inorganic particles used in the P4 layer can be used. In the present invention, in view of the fact that it is often used outdoors, the inorganic particles in the P6 layer are obtained when a metal oxide such as titanium oxide, zinc oxide, cerium oxide or the like having ultraviolet absorbing ability is used. It is preferable in that it can exhibit the effect of reducing coloration due to deterioration of the back sheet over a long period of time by utilizing the ultraviolet resistance by the inorganic particles. Furthermore, it is more preferable to use titanium oxide as inorganic particles in the P6 layer in that high reflection characteristics can be imparted, and it is more preferable to use rutile type titanium oxide in terms of higher ultraviolet resistance.

Formula (4) represents the range of the thickness of the entire back sheet. When Ta is smaller than 200 μm, heat resistance and water vapor permeability may be inferior. When Ta is larger than 500 μm, processability is poor and conveyance is difficult, so that process suitability may be poor, and a solar cell module that is required to be lightweight and save space may be too thick.

Formula (5) shows the ratio of the thickness of the P4 layer to the total thickness, and the heat resistance improves as the thickness of the P4 layer increases. Therefore, if the value of T4 / Ta is less than 0.3, the heat resistance May decrease. The durability increases as the value of T4 / Ta increases. However, since the P4 layer is often expensive in comparison with the P6 layer, it is preferably 0.5 or less from the viewpoint of reducing the product cost.

The thickness T5 (μm) of the P5 layer is preferably 15 to 50 μm. When there are a plurality of P5 layers, the thickness T5 (μm) of each P5 layer is preferably 15 to 50 μm. When T5 is smaller than 15 μm, the adhesion with the P4 layer or the P6 layer is lowered, and delamination may occur. When T5 is larger than 50 μm, the flame retardancy is likely to deteriorate when the combustibility of the backsheet is confirmed. T5 is more preferably 20 μm or more and 40 μm or less. Here, delamination refers to what peels at the interface such as between the P4 layer and the P5 layer and between the P5 layer and the P6 layer.

The laminated structure of the back sheet in the present invention is a structure in which at least the P4 layer is located on the surface layer, and the P6 layer is located on the surface opposite to the P4 layer. Here, the P6 layer being positioned on the reverse surface layer of the P4 layer means that the P4 layer is positioned on one outermost layer of the backsheet and therefore the P6 layer is positioned on the other outermost layer. From such a viewpoint, the layer configuration (layer order) of the backsheet of the present invention is preferably P4 layer / P5 layer / P6 layer.

Next, the backsheet manufacturing method of the present invention will be described in detail with respect to an embodiment having a P4 layer, a P5 layer, and a P6 layer. Examples of the method of laminating the P4 layer, the P5 layer, and the P6 layer in the backsheet of the present invention include, for example, a polyamide resin for the P4 layer or a raw material mainly comprising polybutylene terephthalate, and a low crystalline softness for the P5 layer. A raw material mainly composed of one selected from the group consisting of a polymer, an acrylic adhesive, and an ethylene vinyl acetate copolymer, and a raw material mainly composed of an olefin resin for the P6 layer are separately extruded. A sheet manufactured by a manufacturing method (co-extrusion method) including a step of feeding a P4 layer, a P5 layer, and a P6 layer after being melted together, laminating them in this order, and extruding them into a sheet form from a T die. A method of laminating a coating layer raw material into an extruder and laminating while extruding and extruding from a die (melt laminating method), producing each sheet separately, A method of thermocompression bonding with a heated group of rolls (thermal lamination method), a method of bonding via an adhesive (adhesion method), a method of applying and drying a solution dissolved in a solvent (coating method), and A method combining these can be used. Of these, the coextrusion method is preferred in that the production process is short and the adhesion between the layers is good. Hereafter, the manufacturing method by a coextrusion method is explained in full detail.

When the backsheet of the present invention is produced by the coextrusion method, first, a dried polyamide resin for P4 layer or a raw material mainly comprising polybutylene terephthalate, a low crystalline soft polymer for P5 layer, an acrylic adhesive And a raw material mainly composed of one selected from the group consisting of ethylene vinyl acetate copolymer and a raw material mainly composed of an olefin resin for P6 layer under a nitrogen stream, a raw material for P4 layer The raw material for P5 layer and the raw material for P6 layer are fed to three extruders heated to 180 ° C or higher and 250 ° C or lower, respectively, and melted. Next, using a multi-manifold die, a feed block, a static mixer, pinol, etc., the P4 layer, the P5 layer and the P6 layer are joined and laminated in this order, and are coextruded from the T die into a sheet. When the difference in melt viscosity of each layer is large, it is preferable to use a multi-manifold die from the viewpoint of suppressing lamination unevenness.

The back sheet discharged from the T die by the above method is extruded onto a cooling body such as a casting drum and solidified by cooling, whereby the back sheet of the present invention can be obtained.

The back sheet of the present invention obtained by the above-described method may be subjected to processing such as heat treatment or aging as necessary within the range where the effects of the present invention are not impaired. By heat-treating, the thermal dimensional stability of the backsheet of the present invention can be improved. Moreover, in order to improve the adhesiveness of the backsheet of the present invention obtained by the above method, corona treatment or plasma treatment may be performed.

The solar cell module of the present invention has the back sheet for solar cell of the present invention. By using the back sheet of the present invention in a solar cell module, it is possible to maintain power generation characteristics for a long period of time compared to a conventional solar cell module. A configuration example of the solar cell module of the present invention is shown in FIG. In FIG. 1, a solar cell connected with a lead wire for taking out electricity (not shown in FIG. 1) is sealed with a transparent sealing material 2 such as EVA resin, and a transparent substrate 4 such as glass. The solar cell backsheet 1 of the present invention is bonded together, and the configuration example of the solar cell module of the present invention is not limited to this and can be used for any configuration.

In the solar cell module of the present invention, the above-described solar cell backsheet 1 is installed on the back surface of the sealing material 2 that seals the solar cells. Here, the solar cell backsheet of the present invention has an asymmetric configuration, and the P6 layer is disposed so as to be positioned on the sealing material 2 side, so that the adhesion with the sealing material can be further increased. This is preferable. Moreover, since it becomes the structure arrange | positioned so that P4 layer of the back sheet | seat of this invention may be located in the opposite side to the sealing material 2, it becomes possible to raise the tolerance with respect to the ultraviolet-ray of reflection from the ground, etc., and highly durable. It can be a solar cell module or the thickness can be reduced.

The solar battery cell 3 converts light energy of sunlight into electric energy, and is made of polycrystalline silicon, polycrystalline silicon, microcrystalline silicon, amorphous silicon, copper indium selenide, compound semiconductor, Arbitrary elements, such as a dye sensitizing system, can be used in series or in parallel according to the desired voltage or current depending on the purpose. Since the transparent substrate 4 having translucency is located on the outermost layer of the solar cell module, a transparent material having high weather resistance, high contamination resistance, and high mechanical strength characteristics in addition to high transmittance is used. In the solar cell module of the present invention, the transparent substrate 4 having translucency can use any material as long as it satisfies the above characteristics. Examples thereof include glass, ethylenetetrafluoroethylene (ETFE), and polyvinyl fluoride (PVF). ), Fluorinated resins such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (TFE), tetrafluoroethylene-hexafluoropropylene (FEP), polytrifluoroethylene chloride (CTFE), polyvinylidene fluoride, Preferred examples include olefin resins, acrylic resins, and mixtures thereof. In the case of glass, it is more preferable to use a tempered glass. Moreover, when using the resin-made translucent base material, what extended | stretched the said resin uniaxially or biaxially from a viewpoint of mechanical strength is used preferably.

In addition, in order to impart adhesion to the EVA resin or the like, which is a sealing material for solar cells, it is preferable that the surface is subjected to corona treatment, plasma treatment, ozone treatment, and easy adhesion treatment. Done.

The sealing material 2 for sealing the solar battery cell covers and fixes the unevenness of the surface of the solar battery cell with a resin, protects the solar battery cell from the external environment, and has a light transmitting property in addition to the purpose of electrical insulation. Therefore, a material having high transparency, high weather resistance, high adhesion, and high heat resistance is used. Examples thereof include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA) resin, ethylene-methacrylic acid copolymer (EMAA), Ionomer resins, polyvinyl butyral resins, and mixtures thereof are preferably used.

As described above, by incorporating the solar cell backsheet of the present invention into a solar cell module, it becomes possible to obtain a highly durable and / or thin solar cell as compared with a conventional solar cell. The solar cell module of the present invention is not limited to outdoor use and indoor use, such as a solar power generation system and a power source for small electronic components, and can be suitably used for various uses.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not necessarily limited thereto. In addition, the various characteristic evaluation described in this specification was performed as follows.

[Characteristic evaluation method]
(1) Layer thickness T1, T2, T3, T4, T5, T6, Ta, lamination ratio T4 / Ta
It was determined by the following procedures (A1) to (A4). The measurement was carried out at 10 different locations, and the average values were P1 layer thickness T1 (μm), P2 layer thickness T2 (μm), P3 layer thickness T3 (μm), P4 layer thickness T4 ( μm), the thickness T5 (μm) of the P5 layer, the thickness T6 (μm) of the P6 layer, and the thickness Ta (μm) of the entire sheet. Furthermore, the stacking ratio T4 / T6 was determined using T4 and T6 obtained here.

(A1) Using a microtome, cut the cross section of the laminated sheet (back sheet) perpendicular to the plane direction of the laminated sheet (back sheet) without crushing the cross section in the thickness direction.

(A2) Next, the cut section is observed using an electron microscope, and an image magnified 500 times is obtained. Although the observation location is determined at random, the vertical direction of the image is parallel to the thickness direction of the laminated sheet (back sheet) and the horizontal direction of the image is parallel to the surface direction of the laminated sheet (back sheet). To. When the entire thickness direction does not fit in one image, observation is performed by shifting the observation position in the thickness direction, and an image that can confirm the entire thickness is prepared by combining a plurality of images.

(A3) P1 layer thickness T1, P2 layer thickness T2, P3 layer thickness T3, P4 layer thickness T4, P5 layer thickness T5, P6 layer thickness T6, sheet in the image obtained in (A2) The total thickness Ta was determined.

(A4) T4 was divided by Ta to calculate a stacking ratio T4 / Ta.

(2) Content of inorganic particles (% by mass)
The P1 layer, P3 layer, P4 layer, and P6 layer are each cut or peeled off from the laminated sheet (back sheet) to separate the P1 layer, P3 layer, P4 layer, and P6 layer. The content of particles was calculated.

The mass wa (g) of the shaved material was measured, and then the P1 layer was dissolved in ortho-cresol, the P3 layer and the P6 layer in ortho-dichlorobenzene (100 ° C.), the P4 layer was dissolved in formic acid, and the insoluble component was dissolved by centrifugation. Of these, inorganic particles were collected. The obtained inorganic particles were washed with ortho-cresol, ortho-dichlorobenzene, formic acid and centrifuged. The washing operation was repeated until no white turbidity occurred even when ethanol was added to the washing solution after centrifugation. Mass wa ′ (g) of the obtained inorganic particles was obtained, and the content of inorganic particles was calculated from the following formula.
Inorganic particle content (% by mass) Wa1 = (wa ′ / wa) × 100.

(3) Crystallization parameters {Glass transition temperature Tg, crystallization temperature Tc, crystallization parameter ΔTcg}
Using a differential scanning calorimeter DSCII type manufactured by Seiko Instrument Co., Ltd., the glass transition temperature (Tg) and the crystallization temperature (Tc) at the time of temperature increase were measured according to JIS-K7121 (1987). First, 5 mg of a sample was collected and heated from 25 ° C. to 300 ° C. at a rate of temperature increase of 20 ° C./min to obtain Tg and Tc, and the crystallization parameter ΔTcg was obtained from the following equation.
ΔTcg = Tc−Tg
When a plurality of Tg and Tc are observed, ΔTcg is calculated using all Tc and Tg satisfying the relationship of Tc> Tg, and the smallest value among them is defined as ΔTcg of the present application.

(4) Measurement of elongation at break and measurement of strength at break Based on ASTM-D882 (1997), a sample was cut into a size of 1 cm × 20 cm, and the elongation at break when pulled between chucks at 5 cm and at a pulling speed of 300 mm / min. The breaking strength was measured. In addition, about each of the longitudinal direction of a film, and the width direction, after measuring the number of samples by n = 5, those average values were made into breaking elongation and breaking strength.
When the breaking strength is 80 MPa or more: S
When the breaking strength is 40 MPa or more and less than 80 MPa: A
When the breaking strength is 30 MPa or more and less than 40 MPa: B
When the breaking strength is 20 MPa or more and less than 30 MPa: C
When the breaking strength is less than 20 MPa: D
S to C pass, and S is the best among them.

(5) Moist heat resistance (Elongation retention after moist heat test)
After the sample was cut into the shape of the measurement piece (1 cm x 20 cm), it was treated for 1000 hours under the conditions of a constant temperature and humidity chamber PR-1KPH manufactured by ESPEC CORP. At a temperature of 85 ° C and a relative humidity of 85% RH. Then, the elongation at break was measured according to the above item (4). In addition, the measurement was made into n = 5, and after measuring about 5 samples of the vertical direction and the horizontal direction of a lamination sheet, the average value was made into elongation at break E1. Moreover, also about the lamination sheet before performing a process, breaking elongation E0 was measured according to the said (4) term, and elongation retention was computed by the following formula using the obtained breaking elongation E0 and E1.
・ Elongation retention (%) = (E1 / E0) × 100
The obtained elongation retention was determined as follows.
When the elongation retention is 50% or more: S
When the elongation retention is 40% or more and less than 50%: A
When the elongation retention is 30% or more and less than 40%: B
When the elongation retention is 20% or more and less than 30%: C
When the elongation retention is less than 20%: D
S to C pass, and S is the best among them.

(6) Heat resistance (elongation retention after heat test)
After the sample was cut into the shape of the measurement piece (1 cm × 20 cm), it was treated for 2000 hours under the condition of a temperature of 140 ° C. in the heat treatment device GPHH-102 manufactured by Espec Co., Ltd., and then according to the above item (4) The elongation at break was measured. In addition, the measurement was made into n = 5, and after measuring about 5 samples of the vertical direction and the horizontal direction of a lamination sheet, the average value was made into elongation at break E1. Moreover, also about the lamination sheet before performing a process, breaking elongation E0 was measured according to the said (4) term, and elongation retention was computed by the following formula using the obtained breaking elongation E0 and E1.
・ Elongation retention (%) = (E1 / E0) × 100
The obtained elongation retention was determined as follows.
When the elongation retention is 50% or more: S
When the elongation retention is 40% or more and less than 50%: A
When the elongation retention is 30% or more and less than 40%: B
When the elongation retention is 20% or more and less than 30%: C
When the elongation retention is less than 20%: D
S to C pass, and S is the best among them.

(7) Weather resistance of P1 layer surface (color change Δb after ultraviolet irradiation)
The sheet was heated at 60 ° C., relative humidity 50%, intensity 100 mW / cm ² (light source: metal halide lamp, wavelength range: 295 to 450 nm, peak wavelength: 365 nm) using I-super ultraviolet tester S-W131 manufactured by Iwasaki Electric Co., Ltd. Irradiation was performed for 48 hours from the P1 side under these conditions. For samples before and after irradiation, the number of samples is n = 5 and a spectroscopic color difference meter SE-2000 type (manufactured by Nippon Denshoku Industries Co., Ltd.) is used, and irradiation is performed in a reflection mode according to JIS Z-8722 (2000). The b values before and after the irradiation were determined by measuring the b values before and after the P1 layer and calculating the average value. The difference (b value after irradiation to b value before irradiation) was defined as a color tone change Δb1 after ultraviolet irradiation.
The obtained color tone change (Δb1) was determined as follows.
When the color change Δb1 is 1 or less: S
When the color tone change Δb1 is greater than 1 and 3 or less: A
When the color change Δb1 is greater than 3 and less than or equal to 6: B
When the color tone change Δb1 is greater than 6 and less than or equal to 9: C
When the color change Δb1 is greater than 9: D
S to C pass, and S is the best among them.

(8) Weather resistance of P3 layer surface (color tone change Δb after UV irradiation)
The sheet was heated at 60 ° C., relative humidity 50%, intensity 100 mW / cm ² (light source: metal halide lamp, wavelength range: 295 to 450 nm, peak wavelength: 365 nm) using I-super ultraviolet tester S-W131 manufactured by Iwasaki Electric Co., Ltd. Irradiation was performed for 48 hours from the P3 side under the above conditions. For samples before and after irradiation, the number of samples is n = 5 and a spectroscopic color difference meter SE-2000 type (manufactured by Nippon Denshoku Industries Co., Ltd.) is used, and irradiation is performed in a reflection mode according to JIS Z-8722 (2000). The b values before and after the irradiation were determined by measuring the b values before and after the P3 layer and calculating the average value. The difference (b value after irradiation from b value after irradiation) was defined as a color tone change Δb2 after ultraviolet irradiation.
The obtained color tone change (Δb2) was determined as follows.
When the color change Δb2 is 1 or less: S
When the color tone change Δb2 is greater than 1 and 3 or less: A
When the color change Δb2 is greater than 3 and less than or equal to 6: B
When the color change Δb2 is greater than 6 and less than or equal to 9: C
When the color change Δb2 is greater than 9: D
S to C pass, and S is the best among them.

(9) Adhesiveness with sealing material Based on JIS K6854 (1994), the adhesiveness of the sealing material was evaluated from the peel strength between the EVA sheet (sealing material) and the P3 layer. The test specimen was a 500 μm thick EVA sheet manufactured by Sanvic Co., Ltd., and a laminated sheet of Examples and Comparative Examples subjected to corona treatment on a 3 mm thick semi-tempered glass, and a commercially available glass laminator was used. Then, after evacuation, a press treatment was performed for 15 minutes with a load of 29.4 N / cm ² under a heating condition of 140 ° C. The width of the test piece for the peel strength test was 10 mm, two test pieces were prepared, and each test piece was measured at three locations with different locations, and the average value of the obtained measured values was taken as the peel strength value.

From the obtained peel strength, the adhesion with the sealing material was determined as follows.
When peel strength is 50 N / 10 mm or more: S
When the peel strength is 40 N / 10 mm or more and less than 50 N / 10 mm: A
When peel strength is 30N / 10mm or more and less than 40N / 10mm: B
When the peel strength is 20 N / 10 mm or more and less than 30 N / 10 mm: C
When peel strength is less than 20 N / 10 mm: D
S to C pass, and S is the best among them.

(10) Interlayer adhesion The interlayer adhesion was evaluated from the delamination strength after treatment at 85 ° C and 85% RH for 1000 hours. Here, as the delamination strength, the strength at the time of peeling in the T shape measured according to JIS K6854-3 (1999) was used. Here, the interlayer was defined as an interlayer capable of interfacial separation such as between the P1 layer and the P2 layer and between the P2 layer and the P3 layer. The test piece width of the delamination strength test was 15 mm, and two test pieces were prepared. The test piece was changed in place and measured at three locations, and the average value of the obtained measurement values was taken as the delamination strength. The interlayer adhesion was determined as follows.
When peel strength is 10N / 15mm or more: S
When the peel strength is 6 N / 15 mm or more and less than 10 N / 15 mm: A
When peel strength is 3N / 15mm or more and less than 6N / 15mm: B
When peel strength is 1N / 15mm or more and less than 3N / 15mm: C
When peel strength is less than 1 N / 15 mm: D
S to C pass, and S is the best among them.

(11) Water vapor transmission rate Pw (g / m ² / day) at 40 ° C. and 90% RH
According to the infrared sensor method of JIS K7129 (2008), the water vapor transmission rate in a measurement area of 50 cm ² and a 40 ° C. and 90% RH environment was measured.

(12) Acetic acid permeability at 85 ° C. Pa (g / m ² / day)
FIG. 2 shows a cross-sectional view and FIG. 3 shows a top view of the jig 11 used for measuring acetic acid permeability. The jig 11 is made of stainless steel and has a 65 cm ² circular opening, and a jig lower part which is a container containing acetic acid having the same shape as the jig 7 on the upper surface of the container. The acetic acid stock solution 9 is put into the lower part 8 of the jig.

The laminated sheet to be measured, the back sheet 1, has a mesh 10 made of stainless steel with a wire diameter of 0.29 mm and a mesh size of 0.98 mm between the jig lower part 8 and the jig upper part 7 on the jig upper part 7 side. The jig upper part 7 and the jig lower part 8 were fixed with screws so as to prevent acetic acid vapor from escaping and sandwiched together with an O-ring set on the jig lower part 8. The mass W1 at room temperature after the jig 11 prepared with the back sheet 1 and the acetic acid stock solution 9 satisfying the measurement area of 65 cm ² was left at 85 ° C. for 1 hour in that state was measured. After the W1 measurement, the mass W2 at room temperature after standing again at 85 ° C. for 1 hour was measured. Similarly, mass W3 at room temperature after standing for 1 hour after W2 measurement and mass W4 at room temperature after 1 hour after W3 measurement were measured. The obtained W1 to W4 were calculated according to the following formula to calculate Pa.
Pa (g / m ² / day) =
{(W1-W2) + (W2-W3) + (W3-W4)} / 3 × 24 / 0.0065.

(13) Evaluation of power generation characteristics of solar cell module The initial maximum output measured according to the standard condition of JIS C8914 (2005) and the constant temperature and humidity test tank “Esspec Corp. constant temperature and humidity test tank PL-4KT” The maximum output after performing the deterioration acceleration test at 85 ° C. and 85% RH for 5000 hours was compared, and the maximum output retention rate after the test was calculated. The power generation characteristics were determined as follows from the obtained maximum output retention rate.
When the maximum output retention rate is 75% or more: S
When the maximum output retention rate is 50% or more and less than 75%: A
When the maximum output retention rate is 25% or more and less than 50%: B
When the maximum output retention rate is less than 25%: C
S and A are acceptable, and S is the best among them.

(14) Discoloration confirmation of cell current collecting electrode (cell current collecting electrode discoloration)
The surface-side collector electrode included in the solar cells of the solar cell module is subjected to a deterioration acceleration test at 85 ° C. and 85% RH for 5000 hours using a constant temperature and humidity test tank “constant temperature and humidity test tank PL-4KT manufactured by ESPEC Corporation”. Thereafter, the color change was visually confirmed with respect to the number of samples n = 5. From the obtained number of samples having discoloration, the discoloration of the cell collector electrode portion was determined as follows.
When the number of discolored samples is n = 0: S
When the number of discolored samples is n = 1 or 2: A
When the number of discolored samples is n = 3 or 4: B
When the number of discolored samples is n = 5: C
S to A are acceptable, and S is the best among them.

(15) The P6 layer yellowed backsheet was cut into the shape of a measurement piece (3 cm × 3 cm), and then subjected to treatment at 120 ° C. for 72 hours in a hot air oven PV (H) -212 manufactured by Espec Corp. With respect to the samples before and after the treatment, the spectroscopic color difference meter SE-2000 type (manufactured by Nippon Denshoku Industries Co., Ltd.) was used with the number of samples n = 5, and in the reflection mode according to JIS Z-8722 (2000). The sample measurement diameter was set to 30 mmφ, the b value on the P6 layer side was measured, and the average value was calculated to obtain the difference between the b values before and after the treatment. That is, Δb was obtained by subtracting the b value before processing from the b value after processing, and the following determination was performed.
When the color change Δb is less than 3: S
When the color change Δb is 3 or more and less than 5: A
When the color change Δb is 5 or more and less than 8: B
When color change Δb is 8 or more and 10 or less: C
When the color change Δb exceeds 10, D.

(16) Heat resistance (130 ° C)
Based on ASTM-D882 (1997), the back sheet was cut into a size of 1 cm × 20 cm, and between chucks before and after being left in a hot air oven PV (H) -212 manufactured by ESPEC Corporation for 1000 hours in an environment of 130 ° C. The breaking elongation reduction rate was measured when pulled at 5 cm and a pulling speed of 300 mm / min. The rate of decrease in elongation at break was the average value after measuring the number of samples at n = 5 in each of the longitudinal direction and the width direction of the film. Judgment was made from the obtained rate of decrease in elongation at break as follows.
When the elongation at break is 70% or more: S
When the elongation at break is 50% or more and less than 70%: A
When the elongation at break is 30% or more and less than 50%: B
When the elongation at break is less than 30%: C.

(17) Partial discharge voltage The partial discharge voltage of the back sheet was determined using a partial discharge tester KPD2050 (manufactured by Kikusui Electronics Co., Ltd.). The test conditions are as follows.
The output voltage application pattern on the output sheet is a pattern in which the first stage simply increases the voltage from 0 V to a predetermined test voltage, the second stage is a pattern that maintains a predetermined test voltage, and the third stage is a predetermined test A pattern composed of three stages of patterns in which the voltage is simply dropped from 0 to 0 V is selected.
・ The frequency is 50 Hz. The test voltage is 1 kV.
The first stage time T1 is 10 sec, the second stage time T2 is 2 sec, and the third stage time T3 is 10 sec.
• The counting method on the pulse count sheet is “+” (plus), and the detection level is 50%.
-The charge amount in the range sheet is set to 1,000 pc.
・ In the protection sheet, enter 2 kV after checking the voltage check box. The pulse count is 100,000.
In the measurement mode, the start voltage is 1.0 pc and the extinction voltage is 1.0 pc.

In addition, the measurement was carried out at 10 arbitrary positions in the film plane, and the average value was defined as the partial discharge voltage V0. Further, the measurement was performed using a measurement sample left overnight in a room at 23 ° C. and 65% RH.
When partial discharge voltage is 1,050 V or more: S
When the partial discharge voltage is 950 V or more and less than 1,050 V: A
When partial discharge voltage is 700V or more and less than 950V: B
When the partial discharge voltage is 300V or more and less than 700V: C
When partial discharge voltage is less than 300V: D.

(18) Adhesion with sealing material (135 ° C vacuum lamination)
Based on JIS K6854 (1994), the adhesion between the EVA sheet (sealing material) and the P6 layer of the back sheet was evaluated from the peel strength. The test specimen is a 500 μm thick EVA sheet manufactured by Sanvic Co., Ltd. and a corona-treated Example and Comparative Example back sheet on a 3 mm thick semi-tempered glass, and a commercially available glass laminator is used. Then, after evacuation, press-treated for 15 minutes with a load of 29.4 N / cm ² under a heating condition of 135 ° C. was used. The width of the test piece for the peel strength test was 10 mm, two test pieces were prepared, and each test piece was measured at three locations with different locations, and the average value of the obtained measured values was taken as the peel strength value. From the obtained peel strength, the adhesiveness of the sealing material was determined as follows. In the case of a backsheet not having the P6 layer, the evaluation is performed in the same manner.
When peel strength is 50 N / 10 mm or more: S
When the peel strength is 40 N / 10 mm or more and less than 50 N / 10 mm: A
When peel strength is 30N / 10mm or more and less than 40N / 10mm: B
When the peel strength is 20 N / 10 mm or more and less than 30 N / 10 mm: C
When peel strength is less than 20 N / 10 mm: D.

(19) Flatness (curling)
The laminated sheet was cut into a size of 100 mm × width 100 mm, placed on a flat surface so as to be concave when viewed from the side, and the height of the four corners raised was measured. The total value at that time was determined as the curl height as follows.
When the total height of the four corners of the curl is less than 20 mm: S
When the total height of the four corners of the curl is 20 mm or more and less than 50 mm: A
When the total height of the four corners of the curl is 50 mm or more and less than 80 mm: B
When the total height of the four corners of the curl is 80 mm or more and less than 100 mm: C
When the total height of the four corners of the curl is 100 mm or more: D
S to C are good, and S is the best among them.

(20) The P1 layer is scraped from the rigid amorphous amount laminated sheet, and subjected to differential scanning calorimetry (DSC) and temperature modulation DSC method with the following apparatus and conditions. 65, no. 11 (2009) P.I. The amount of rigid amorphous was calculated using the method 428.
<DSC method>
Apparatus: DSC Q1000 manufactured by TA Instruments
Atmosphere: Nitrogen flow (50 mL / min)
Temperature / calorie calibration: High purity indium Temperature range: 0-250 ° C
Temperature increase rate: 10 ° C / min
Sample weight: 10mg
Sample container: Aluminum standard container <Temperature modulation DSC method>
Apparatus: DSC Q1000 manufactured by TA Instruments
Atmosphere: Nitrogen flow (50 mL / min)
Temperature / calorie calibration: High purity indium specific heat calibration: Sapphire temperature range: 0-300 ° C
Temperature increase rate: 2 ° C / min
Sample weight: 5mg
Sample container: Aluminum standard container Note that the rigid amorphous amount: χra (%) was calculated by the following formula.
χc (%) = (ΔHm−ΔHc) / ΔHm ⁰ × 100
χma (%) = ΔCp / ΔCp ⁰ × 100
χra (%) = 100− (χc + χma)
χra: rigid amorphous amount χc: crystallinity χma: movable amorphous amount ΔHm: heat of fusion ΔHc: heat of cold crystallization ΔHm ⁰ : heat of complete crystal melting (145.3 J / g)
ΔCp: specific heat difference ΔCp ⁰ : complete amorphous specific heat difference (0.3497 J / (g · ° C.)).

(21) Particle size (average particle size) of inorganic particles
The P3 layer is shaved or peeled off from the laminated sheet and separated, and the mass W (g) is measured. Inorganic particles were separated from insoluble components by dissolution in ortho-dichlorobenzene (100 ° C.) and centrifugation. The obtained inorganic particles are further washed with a solvent and centrifuged, and then the mass Wt of the obtained inorganic particles is measured. The washing operation was repeated until no white turbidity occurred even when ethanol was added to the washing solution after centrifugation.
After filtering the obtained inorganic particles with Whatman quantitative filter paper grade 44, the particle size distribution is obtained by laser analysis / scattering method for the remaining components, and the average particle size is determined by 50% of the integrated value in the particle size distribution. It was. The particle size distribution referred to here is “Laser diffraction / scattering particle size distribution analyzer LS series” (Beckman Coulter, Inc.), Mayumi Toyoda, “Measuring particle size distribution” (Beckman Coulter, Inc., Particle Properties Division, Academic Team) Sought in accordance with The measurement solution was prepared so that inorganic particles were added to pure water and dispersed with a homogenizer for 1 minute, so that the display of the concentration adjustment window of the apparatus was 45 to 55%.

First, the first to thirteenth inventions will be described with reference to Examples 1 to 26, 57 to 72, and Comparative Examples 1 and 2.

(material)
Polybutylene terephthalate resin “Trecon” (registered trademark) 1200M (manufactured by Toray Industries, Inc.) as the polybutylene terephthalate resin (PBT) constituting the P1 layer in Examples 1 to 26, 57 to 72, and Comparative Example 1 Using.

・ Polyolefin resin Examples 1 to 26, 57 to 72, “NOBREN” (registered trademark) WF345S manufactured by Sumitomo Chemical Co., Ltd. (3.5% by mass of ethylene, butene) as the polyolefin resin constituting the P3 layer in Comparative Example 2 4.0% by mass) was used as EPBC1.

For Example 25, “Noblen” (registered trademark) FLX80E4 manufactured by Sumitomo Chemical Co., Ltd. was used as PP1.
Acid Modified Polyolefin “Modic” (registered trademark) P553A manufactured by Mitsubishi Chemical Corporation was used as Resin 1 as the resin constituting the P2 layer in Examples 1 to 26 and 57 to 72.
Polyolefin Elastomer For Example 24, “Notio” (registered trademark) PN2060 manufactured by Mitsui Chemicals, Inc. was used as the elastomer 1 as the polyolefin elastomer.
Inorganic particles Examples 1-5, 7-26, 57-72, P1 layer of Comparative Example 1 and Examples 1-9, 11-26, Inorganic particles of P3 layer of Comparative Example 2 use titanium dioxide It was. In addition, the titanium dioxide of the P1 layer has a desired concentration of a masterbatch prepared in a ratio of 50% by mass / 50% by mass of the resin and titanium dioxide used as main components of the P1 layer in each example and comparative example. Added. For the P3 layer titanium dioxide, a master batch prepared by adding 30% by mass / 70% by mass of the resin and titanium dioxide used as the main constituent components of the P3 layer for each example and comparative example was added to a desired concentration. .
End-capping agent The end-capping agent used for the P1 layer of Examples 1, 3 to 25, 57 to 72 and Comparative Example 1 was P-400 manufactured by Rhein Chemie. For Example 26, “Carbodilite” (registered trademark) HMV-15CA manufactured by Nisshinbo Chemical Co., Ltd. was used.
Crystal nucleating agent Sodium montanate was used as the crystal nucleating agent for the P1 layer of Examples 61 to 63.
・ Inorganic particles (3μm to 20μm)
As the inorganic particles of 3 μm or more and 20 μm or less of the P3 layer of Examples 64-72, talc having an average particle diameter of 5 μm was used.

(Examples 1 to 26, 61 to 72)
Using the extruder 1, the extruder 2 and the extruder 3, the raw materials shown in Table 1 and Table 5 are supplied to each extruder so as to have a desired blending ratio, and then the layer melt-extruded from the extruder 1 is P1. Layers, Extruder 2 is P2 layer, Extruder 3 is P3 layer, P1 layer / P2 layer / P3 layer are laminated in order of multi-manifold, and the resin discharged from the die is 25 ° C. A laminated sheet was obtained by cooling and solidifying on a cast drum. The thicknesses shown in Tables 1 and 5 were obtained for the P1, P2, and P3 layers. The evaluation shown in Table 2 and Table 6 was implemented about the obtained lamination sheet. As a result, as shown in Tables 2 and 6, the examples were found to be excellent laminated sheets.

Furthermore, since Example 24 contained an elastomer in the P2 layer, the interlayer adhesion was extremely excellent.

(Examples 57 to 60)
A laminated sheet was prepared in the same manner as in Example 1 except that the cast drum temperature was changed to 15 ° C. (Example 57), 20 ° C. (Example 58), 40 ° C. (Example 59), and 50 ° C. (Example 60), respectively. did. The evaluation shown in Table 6 was implemented about the obtained lamination sheet. As a result, as shown in Table 6, it was found that the examples were excellent laminated sheets.
(Comparative Example 1)
Using the extruder 1, the raw materials shown in Table 1 are supplied to the extruder so as to have a desired mixing ratio, and then the resin melt-extruded from the extruder 1 and discharged from the die is cooled and solidified on a cast drum to form a single layer A sheet was obtained. Since there was no polyolefin resin layer, the adhesion with the sealing material was poor.

(Comparative Example 2)
Using the extruder 3, the raw materials shown in Table 1 are supplied to the extruder so as to have a desired blending ratio, and then the resin melt-extruded from the extruder 3 and discharged from the die is cooled and solidified on a cast drum to form a single layer A sheet was obtained. Since there was no polybutylene terephthalate resin layer, the heat and moisture resistance and heat resistance were poor.

It is possible to provide a laminated sheet capable of achieving both heat and moisture resistance, heat resistance, and adhesion between the sealing material and the laminated sheet using a conventional polybutylene terephthalate resin. Such laminated sheets are suitable for use in applications where importance is placed on wet heat resistance, resistance to ultraviolet rays, and light reflectivity, including solar cell backsheets, liquid crystal display reflectors, automotive materials, and building materials. can do. In particular, a laminated sheet that can be suitably used as a solar battery backsheet, and a method for producing the laminated sheet can be provided.

Next, the fourteenth to twentieth inventions will be described with reference to Examples 27 to 56 and Comparative Examples 3 to 5.

(Examples 27 to 56, Comparative Example 5)
(material)
Polyamide resin Nylon 6 resin “Amilan” (registered trademark) CM1021T (manufactured by Toray Industries, Inc.) as the polyamide resin (PA6) constituting the P4 layer in Examples 27, 34 to 39, 41 to 49 and Comparative Examples 4 and 5 Tm; 225 ° C.).

Nylon 66 resin “Amilan” (registered trademark) CM3001 (PA66) per Example 50, Nylon 610 resin “Amilan” (registered trademark) CM2001 (PA610) per Example 51, Nylon 11 resin “Rilsan” BESN- per Example 52 O-TL (PA11), nylon 53 resin “Rilsan” AESN-TL (PA12) was used for Example 53.
Polybutylene terephthalate “Trecon” (registered trademark) 1200M (manufactured by Toray Industries, Inc., Tm; 224 ° C.) was used as the polybutylene terephthalate (PBT) constituting the P4 layer in Examples 29 and 54.
Polyethylene terephthalate As polyethylene terephthalate (PET) constituting the P4 layer in Example 28, a film of 25 μm “Lumirror” (registered trademark) S10 (manufactured by Toray Industries, Inc.) was used.
Polyvinyl fluoride As the polyvinyl fluoride (PVF) constituting the P4 layer in Example 30, a 38 μm “Tedra” (registered trademark) (manufactured by Dupont) film was used.
Ethylenetetrafluoroethylene As ethylenetetrafluoroethylene (ETFE) constituting the P4 layer in Example 31, a film of 50 μm “Toyoflon” (registered trademark) EL (manufactured by Toray Film Processing Co., Ltd.) was used.
-Tetrafluoroethylene-propylene hexafluoride As the tetrafluoroethylene-hexafluoropropylene (FEP) constituting the P4 layer in Example 32, 25 μm "Toyoflon" (registered trademark) FL (Toray Film Processing Co., Ltd.) Manufactured film).
Polyvinylidene fluoride A 30 μm film of Kynar Film 302 PGM TR (manufactured by ARKEMA Corp.) was used as the polyvinylidene fluoride (PVDF) constituting the P4 layer in Example 33.
Olefin resin For Examples 27 to 45, 50 to 54, and Comparative Example 5, "Nobrene" (registered trademark) WF345S (3.5 mass% ethylene, 4.0 mass% butene) manufactured by Sumitomo Chemical Co., Ltd. was used as EPBC1 It was.

For Example 46, “Evolue” (registered trademark) SP2530 manufactured by Sumitomo Chemical Co., Ltd. was used as LLDPE1.

For Example 47, “Evolue” (registered trademark) SP2540 manufactured by Sumitomo Chemical Co., Ltd. was used as LLDPE2.

For Example 48, 1% ethylene copolymer polypropylene was used as EPC1.

In Example 49, “Noblen” (registered trademark) FLX80E4 manufactured by Sumitomo Chemical Co., Ltd. was used as PP1.
Acid Modified Olefin “Modic” (registered trademark) P553A manufactured by Mitsubishi Chemical Corporation was used as Resin 1 as the resin constituting the P5 layer in Examples 34 to 39, 41 to 54, and Comparative Example 5.
-Ethylene vinyl acetate copolymer "Modic" (registered trademark) A515 manufactured by Mitsubishi Chemical Corporation was used as the resin 2 as the resin constituting the P5 layer in Example 55.
Acrylic Adhesive “Bond First” (registered trademark) 7L manufactured by Sumitomo Chemical Co., Ltd. was used as the resin 3 as the resin constituting the P5 layer in Example 56.
Inorganic particles Examples 27, 29, 34 to 39, 41 to 54, inorganic particles used in the P4 layer of Comparative Example 5 and the P6 layer of Examples 27 to 54 and Comparative Example 5 have an average particle size of 0.25 μm. Titanium dioxide was used.

Further, the titanium dioxide of the P4 layer has a desired concentration of the resin used as the main component of the P4 layer and the resin obtained by mastering titanium dioxide at a ratio of 50% by mass / 50% by mass for each example and comparative example. Was added as follows. The titanium dioxide of P6 layer was added so that the resin used as the main component of P6 layer for each Example and Comparative Example and the resin mastered at a ratio of 30% by mass / 70% by mass of titanium dioxide to a desired concentration. .

(Laminated)
Using the extruder 4, the extruder 5 and the extruder 6, the raw materials shown in Tables 3-1 and 3-2 were supplied to each extruder so as to have a desired blending ratio, and then melt-extruded from the extruder 4 The layers are P4 layer, the extruder 5 is P5 layer, the extruder 6 is P6 layer, and the layers are joined together in order of P4 layer / P5 layer / P6 layer, and the resin discharged from the die is discharged. A back sheet was obtained by cooling and solidifying on a cast drum.

Of the backsheets without the P5 layer, Examples 27 and 29 use the extruder 4 and the extruder 6 to supply the raw materials shown in Table 3-1 to each extruder so as to have a desired blending ratio. Next, the layers melt-extruded from the extruder 4 are P4 layers, the extruder 6 is P6 layers, and the layers are joined together in a multi-manifold so that they are laminated in the order of P4 layers / P6 layers, and the resin discharged from the die is cast. A back sheet was obtained by cooling and solidifying on a drum.

Of the backsheets without the P5 layer, Examples 28, 30 to 33, and Comparative Example 3 were used for adhesion between the respective layers by the dry laminating method so as to have the desired configurations shown in Tables 3-1 and 3-2. Lamination was performed using a polyurethane adhesive as an adhesive. At this time, the EPBC 1 used in Examples 28 and 30 to 33 is a resin in which raw materials are supplied to the extruder 6 in advance so as to obtain a desired blending ratio, and then melt extruded from the extruder 6 and discharged from the die. A single layer sheet obtained by cooling and solidifying on a cast drum was used.

In Example 39, raw materials were supplied to the extruder 6 so as to obtain a desired blending ratio, and then the resin melt-extruded from the extruder 6 and discharged from the die was cooled and solidified on a cast drum. A layer sheet was used.

(Solar cell module)
The flux “HOZAN H722” was applied to the front and back silver electrodes of the solar cell “Qcells Q6LPT-G2” with a dispenser, and the wiring was cut to a length of 155 mm on the front and back silver electrodes. The material “Hitachi Cable Co., Ltd. copper foil SSA-SPS0.2 × 1.5 (20)” 10 mm away from one end of the cell on the surface side is the end of the wiring material, and the back side is symmetrical with the surface side. Then, the soldering iron was brought into contact with the soldering iron from the back side of the cell using a soldering iron, and the front and back sides were simultaneously soldered to produce one cell string.

Place the wiring material protruding from the cell of the produced 1-cell string so that the longitudinal direction of the wiring member is perpendicular to the longitudinal direction of the extraction electrode “Cu foil A-SPS 0.23 × 6.0” manufactured by Hitachi Cable, Ltd. Then, the flux was applied to the portion where the wiring material and the take-out electrode overlapped, and solder welding was performed, thereby producing a string with the take-out electrode.

Next, 190 mm × 190 mm glass “3.2 mm thick white plate heat-treated glass for solar cells manufactured by Asahi Glass Co., Ltd.”, 190 mm × 190 mm ethylene vinyl acetate “Sanvik Inc. sealing material 0.5 mm thick”, produced strings with extraction electrodes 190 mm × 190 mm ethylene vinyl acetate “Sealvik 0.5 mm thick sealing material”, 190 mm × 190 mm of each of the back sheets of Tables 3-1 and 3-2 are laminated in order, and the glass is a heating plate of a vacuum laminator And then laminating under the conditions of a hot platen temperature of 145 ° C., a vacuum drawing of 4 minutes, a press of 1 minute, and a holding time of 10 minutes. At this time, the strings with extraction electrodes were set so that the glass surface was on the cell surface side.

The thicknesses of the P4 layer, the P5 layer, and the P6 layer, the acetic acid permeability Pa, and the water vapor permeability Pw were as shown in Tables 3-1 and 3-2. Further, the evaluation shown in Tables 4-1 and 4-2 was performed on the obtained back sheet and the solar cell module using the back sheet. As a result, as shown in Tables 4-1 and 4-2, the examples were found to be excellent backsheets.
In Comparative Example 5, since Pw was larger than 2.5, the color of the cell collector electrode was inferior.

(Comparative Example 3)
For adhesion between each layer by a dry laminating method, a polyurethane adhesive is used as an adhesive, a 125 μm white polyethylene terephthalate film “Lumirror” E20F (manufactured by Toray Industries, Inc.), and an inorganic compound vapor deposition layer made of aluminum oxide. A back sheet in which 12 μm polyethylene terephthalate film “Barrier Rocks” (registered trademark) EG-C2 (manufactured by Toray Film Processing Co., Ltd.) was sequentially laminated was obtained, and acetic acid permeation rate and water vapor transmission rate were measured. For the rate, Pa was 10 g / 24 hr / m ² , and for the water vapor transmission rate, Pw was 0.2 g / 24 hr / m ² . Moreover, a solar cell module was produced using this back sheet, and the maximum output retention rate was compared to about 85 hours at 85 ° C. and 85% RH 5000 hours. As a result, the maximum output retention rate was 10%, and Pa was smaller than 200. Was inferior.

(Comparative Example 4)
Using the extruder 4, the raw materials shown in Table 3-2 are supplied to the extruder so as to have a desired mixing ratio, and then the resin melt-extruded from the extruder 4 and discharged from the die is cooled and solidified on a cast drum. A single layer sheet was obtained. Since Pw was larger than 2.5, discoloration of the cell current collecting electrode was inferior.

1: Back sheet 2: Sealing material 3: Power generation element (solar cell)
4: Transparent substrate 5: Surface of the solar cell back sheet on the side of the sealing material 2 6: Surface of the solar cell back sheet on the side opposite to the sealing material 2 7: Upper part of the jig 8: Lower part of the jig 9: Acetic acid 10: Mesh 11: Jig

Claims

A laminated sheet having a layer (P1 layer) mainly comprising a polybutylene terephthalate resin and a layer (P3 layer) mainly comprising a polyolefin resin.
It has a layer (P2 layer) whose main component is an adhesive polyolefin resin,
The laminated sheet according to claim 1, wherein the P1 layer and the P3 layer are in contact with each other via the P2 layer.
The laminated sheet according to claim 2, wherein the P2 layer has a thickness of 15 to 50 µm.
The laminated sheet according to any one of claims 1 to 3, wherein the crystallization parameter ΔTcg of the P1 layer measured using differential scanning calorimetry (DSC) is 7 to 30 ° C.
When a resin obtained by reacting an end-capping agent with a polybutylene terephthalate resin is used as an end-capped polybutylene terephthalate resin,
The laminated sheet according to any one of claims 1 to 4, wherein the polybutylene terephthalate-based resin, which is a main component of the P1 layer, contains an end-capped polybutylene terephthalate-based resin.
The laminated sheet according to any one of claims 1 to 5, wherein the P3 layer contains 0.1 to 30% by mass of inorganic particles.
The laminated sheet according to any one of claims 1 to 6, wherein the P1 layer has a rigid amorphous amount of 30 to 50%.
The laminated sheet according to any one of claims 1 to 7, wherein the P1 layer contains 0.1 to 5% by mass of a crystal nucleating agent.
The laminated sheet according to any one of claims 1 to 8, wherein the P3 layer contains 5 to 30% by mass of inorganic particles having a particle diameter of 3 to 20 µm and 0.5 to 5% by mass of an adhesive polyolefin resin.
The acetic acid permeability Pa (g / m 2 / day) at 85 ° C. and the water vapor permeability Pw (g / m 2 / day) at 40 ° C. and 90% RH satisfy the formulas (1) and (2). The laminated sheet according to any one of claims 1 to 9, wherein the laminate sheet is characterized.
(1) 200 ≦ Pa
(2) Pw ≦ 2.5
A solar battery back sheet comprising the laminated sheet according to any one of claims 1 to 10.
A solar cell using the solar cell back sheet according to claim 11.
A method for producing a laminated sheet according to any one of claims 2 to 10,
A raw material for the P1 layer containing polybutylene terephthalate resin as the main constituent, a raw material for the P2 layer containing the adhesive polyolefin resin as a main constituent, and a raw material for the P3 layer containing the polyolefin resin as the main constituent , Each of which is supplied to a different extruder, and after melting, each of the P1, P2, and P3 layers is joined and laminated in this order, and is extruded into a sheet form from a T-die, thereby producing a laminated sheet Method.
The acetic acid permeability Pa (g / m 2 / day) at 85 ° C. and the water vapor permeability Pw (g / m 2 / day) at 40 ° C. and 90% RH satisfy the formulas (1) and (2). A back sheet for solar cells, which is characterized.
(1) 200 ≦ Pa
(2) Pw ≦ 2.5
15. The solar cell back according to claim 14, comprising a P4 layer when a layer, one of which is a main constituent selected from the group consisting of a polyester resin, a polyamide resin, and a fluororesin, is a P4 layer. Sheet.