JP2015044333A - Readily adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a readily adhesive sheet which has excellent easy adhesiveness compared to a conventional readily adhesive sheet and can be suitably used in an application exposed to an outdoor environment for a long period of time such as a back sheet for a solar cell.SOLUTION: There is provided a readily adhesive sheet which comprises a substrate layer (P1 layer) composed of a polyester resin composition and a layer (P2 layer) satisfying the following requirements (1) and (2). (1) The P2 layer is a layer formed of a polyamide resin A and a coating composition containing a crosslinking agent B. (2) The content of the polyamide resin A in the coating composition is 50 mass% based on the solid content of the coating composition.

Description

  The present invention relates to an easy-adhesive sheet that has excellent easy-adhesive properties and can be suitably used for solar cell backsheet applications, and a solar cell using the sheet.

  In recent years, solar power generation has attracted attention as a semi-permanent and pollution-free next-generation energy source, and solar cells are rapidly spreading. In a solar cell, a power generating element is sealed with a transparent resin such as an ethylene-vinyl acetate copolymer (hereinafter sometimes referred to as EVA), and a transparent substrate such as glass and a resin sheet called a back sheet are attached. It is configured together.

  Here, the conventional back sheet for solar cells uses a biaxially stretched polyethylene terephthalate (hereinafter referred to as PET) film that is inexpensive and has high performance, and is required to have durability and electrical characteristics required for the back sheet for solar cells. Consideration has been made. However, polyester resins such as PET have poor adhesion to hot melt adhesives (sealing materials) such as EVA. Therefore, conventionally, a polyolefin resin sheet excellent in adhesion to a hot melt adhesive (sealing material) such as EVA is laminated on a polyester resin film such as PET, and the polyolefin resin sheet is laminated with a hot melt adhesive such as EVA ( It was common to use as an easy-adhesion layer with a sealing material.

  In addition, recently, an easy-adhesion sheet (Patent Documents 1, 2, and 3) that can be easily bonded to a hot melt adhesive (sealing material) such as EVA by providing an easy-adhesion layer on the surface of a biaxially stretched PET film. 4) etc. are disclosed.

JP 2006-152013 A Japanese Patent No. 4803317 JP 2012-69835 A International Publication No. 2008/069024 Pamphlet

  However, the conventional easy-adhesive sheets listed in Patent Documents 1 to 4 have insufficient long-term adhesiveness retention. For example, when used for a solar battery backsheet, of course, when processing solar cells, solar batteries While being used outdoors as a cell, there was a problem that the film was easily peeled off. In order to solve this problem, an object of the present invention is to provide a sheet having an easy-adhesive property with excellent long-term adhesion retention.

In order to solve the above problems, the present invention has the following configuration. That is, it has the base material layer (P1 layer) which consists of a polyester resin composition, and the layer (P2 layer) which satisfy | fills the requirements of following (1) and (2) adjacent to at least one side of the said P1 layer, Easy adhesion sheet.
(1) The P2 layer is a layer formed from a coating composition containing a polyamide resin A and a crosslinking agent B.
(2) The content of the polyamide resin A in the coating composition is 50% by mass or more based on the solid content in the coating composition.

  According to the present invention, compared with the conventional easy-adhesive sheet, it has excellent easy-adhesiveness and can be suitably used in applications such as a solar cell backsheet that is exposed to the outdoors for a long period of time. An easily adhesive sheet can be provided.

It is sectional drawing which shows typically an example of a structure of the solar cell using the easily bonding sheet | seat of this invention.

The easy-adhesion sheet in the present invention is a base layer (P1 layer) made of a polyester resin composition and a layer (P2 layer) satisfying the following requirements (1) and (2) adjacent to at least one side of the P1 layer. It is a sheet | seat characterized by having.
(1) The P2 layer is a layer formed from a coating composition containing a polyamide resin A and a crosslinking agent B.
(2) The content of the polyamide resin A in the coating composition is 50% by mass or more based on the solid content in the coating composition.

(Base material layer (P1 layer))
The P1 layer of the present invention is made of a polyester resin composition. In the present invention, the P1 layer made of the polyester resin composition means that the polyester resin is contained in an amount of 80% by mass or more in the resin composition constituting the P1 layer. As the polyester resin constituting the P1 layer, 1) polycondensation of dicarboxylic acid or its ester-forming derivative and diol component, 2) polycondensation of carboxylic acid or carboxylic acid derivative and a compound having a hydroxyl group in one molecule, and 1 ) It can be obtained by the combination of 2).

  In 1), 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, Aliphatic dicarboxylic acids such as ethylmalonic acid, alicyclic dicarboxylic acids such as adamantane dicarboxylic acid, norbornene dicarboxylic acid, cyclohexane dicarboxylic acid, decalin dicarboxylic acid, terephthalic 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, 4,4′-diphenylsulfonedicarboxylic acid Acid, 5-sodium Hoisofutaru acid, phenyl ene boys carboxylic acid, anthracene dicarboxylic acid, phenanthrene carboxylic acid, 9,9'-bis (4-carboxyphenyl) aromatic dicarboxylic acids such as fluorene acid, or the like ester derivatives thereof. These may be used alone or in combination.

  Next, as the diol component, aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, etc. , Cycloaliphatic dimethanol, spiroglycol, isosorbide and other alicyclic diols, bisphenol A, 1,3-benzenedimethanol, 1,4-benzenedimethanol, 9,9'-bis (4-hydroxyphenyl) fluorene, etc. Aromatic diols are typical examples. Moreover, these may be used independently or may be used in multiple types as needed. In addition, a dihydroxy compound formed by condensing a diol with at least one hydroxy terminal of the diol component described above can also be used.

  In 2), examples of compounds having a carboxylic acid or a carboxylic acid derivative and a hydroxyl group in one molecule include oxyacids such as l-lactide, d-lactide and hydroxybenzoic acid, and derivatives thereof, oligomers of oxyacids, dicarboxylic acids Examples thereof include those obtained by condensing an oxyacid with one carboxyl group of the acid.

  The dicarboxylic acid component and the diol component constituting the polyester resin may be selected and copolymerized one by one from the above, or a plurality of each may be selected and copolymerized.

  Specific examples of the polyester resin constituting the P1 layer of the present invention include polyethylene terephthalate, polyethylene-2, 6-naphthalate, polypropylene terephthalate, polybutylene terephthalate, and polylactic acid. Polyethylene terephthalate, polyethylene-2, 6-naphthalate, and polylactic acid are preferred from the viewpoint of improving sheet durability such as heat resistance and heat-and-moisture resistance by imparting biaxial orientation. Polyethylene terephthalate is more preferable from the viewpoint that the material has a certain degree of flexibility to improve easy adhesion. The polyester resin constituting the P1 layer may be a blend of two or more polyester resins.

  The resin constituting the P1 layer of the present invention has a polyester resin as the main constituent as described above, but the intrinsic viscosity IV is 0.65 dl / g or more and 0.80 dl / g or less, and the terminal carboxyl group amount is 25 equivalents / It is preferably less than tons. For example, when the polyester resin constituting the P1 layer is mainly composed of polyethylene terephthalate, if the intrinsic viscosity IV is less than 0.65 dl / g, the durability of the sheet, such as heat resistance and moist heat resistance, may be deteriorated. Moreover, when intrinsic viscosity IV exceeds 0.80 dl / g, when the P1 layer is manufactured, the extrudability of the resin is poor, and sheet molding may be difficult. Furthermore, even if the intrinsic viscosity IV satisfies the above range, if the terminal carboxyl group amount is 25 equivalents / ton or more, the adhesion to the P2 layer is improved, but the durability of the sheet such as heat resistance and moist heat resistance is improved. Since it gets worse, it is not preferable.

  From the above, by making the component of the P1 layer polyethylene terephthalate satisfying the intrinsic viscosity IV and the terminal carboxyl group amount in the above range, the adhesive property is extremely excellent in the durability of the sheet such as heat resistance and moist heat resistance. It can be a sheet. The lower limit of the amount of terminal carboxyl groups is not particularly limited, but it is difficult to make it substantially less than 1 equivalent / ton.

  In the easily adhesive sheet of the present invention, the number average molecular weight of the polyester resin constituting the P1 layer is preferably 18500 to 40000, more preferably 19000 to 35000, and still more preferably 20000 to 33000. When the number average molecular weight of the polyester resin constituting the P1 layer is less than 18500, the durability of the sheet may be lowered, which is not preferable. On the other hand, if it exceeds 40,000, even if the polymerization is difficult or the polymerization can be performed, it may be difficult to extrude the resin with an extruder and film formation may be difficult.

  In the easy-adhesive sheet of the present invention, the P1 layer is preferably uniaxially oriented, and more preferably biaxially oriented. When the P1 layer is uniaxially or biaxially oriented, the durability of the sheet such as heat resistance and moist heat resistance can be improved by orientation crystallization.

  For the purpose of imparting properties such as light resistance, light reflectivity, light hiding property, designability, and visibility to the P1 layer of the present invention, a method of containing inorganic particles having respective functions is also preferably used. For example, in order to improve both light resistance and light reflectivity, it is preferable to contain titanium oxide particles in a range of 1% by mass to 30% by mass with respect to the polyester resin constituting the P1 layer. This makes it possible to exhibit the effect of reducing coloration due to deterioration of the sheet over a long period of time by utilizing the ultraviolet absorbing ability and light reflectivity of the titanium oxide particles. If it is less than 1% by mass, UV resistance may be insufficient. If it is more than 30% by mass, the adhesion between the layers may be deteriorated. A more preferable lower limit is 2% by mass or more, and further preferably 3% by mass or more. A more preferable upper limit is 25% by mass or less, and further preferably 20% by mass or less. Furthermore, it is more preferable to use rutile type titanium oxide in terms of high light reflectivity and light resistance.

  In addition, in order to improve light resistance, light hiding property, and design, particles made of carbon-based materials such as fullerene, carbon fiber, and carbon nanotube are used as the resin constituting the P1 layer (hereinafter sometimes referred to as carbon particles). ) Is preferably contained in the range of 0.1% by mass to 5% by mass. This makes it possible to exhibit the effect of reducing coloration due to deterioration of the sheet over a long period of time by utilizing the ultraviolet absorbing ability and light hiding property of the carbon particles. If it is less than 0.1% by mass, light resistance and light concealment may be insufficient. When the content is more than 5% by mass, the pressure in the furnace becomes high and the extrusion may become difficult or the adhesion between layers may deteriorate when the raw material is melt-extruded in the step of forming the P1 layer. A more preferable lower limit is 0.2% by mass or more, and further preferably 0.5% by mass or more. A more preferable upper limit is 4% by mass or less, and further preferably 3% by mass or less.

  Moreover, as a method of making the polyester resin which comprises P1 layer contain the said particle | grains, the method of melt-kneading a polyester resin and particle | grains using a vent type biaxial kneading extruder or a tandem type extruder is used preferably. Here, when the polyester resin is subjected to a thermal load when the polyester resin contains particles, the polyester resin deteriorates not a little. Therefore, it is preferable to prepare a master pellet having a concentration higher than the particle content contained in the polyester resin constituting the P1 layer, from the viewpoint of suppressing a decrease in durability of the sheet such as heat resistance and heat and humidity resistance. The produced high-concentration master pellets are mixed with a polyester resin and diluted to obtain a particle content of a predetermined P1 layer, thereby suppressing a decrease in intrinsic viscosity IV and an increase in the amount of terminal carboxyl groups.

  In addition to the above titanium oxide particles and carbon particles, the P1 layer in the easy-adhesive sheet of the present invention has a heat resistance stabilizer, an ultraviolet stabilizer, and an antistatic agent as long as the effects of the present invention are not impaired as necessary. Additives such as agents, lubricants, fillers, nucleating agents, dyes, dispersants, coupling agents, etc., and bubbles may be included. For example, when an ultraviolet stabilizer is selected as an additive, the light resistance of the easily adhesive sheet of the present invention can be further increased. Further, by including bubbles, the specific gravity of the sheet can be reduced, reflectivity can be exhibited, and electrical insulation can be imparted.

  The P1 layer of the present invention may have a laminated structure. For example, a laminated structure of a P11 layer excellent in moisture and heat resistance and a layer P12 layer containing a high concentration of an ultraviolet absorber or titanium oxide particles having ultraviolet absorption ability is a preferred form, and the moisture and heat resistance and light resistance of the sheet are preferred. Can be compatible. In the case of having such a laminated structure, the configuration of the easy-adhesive sheet of the present invention is preferably P12 layer / P11 layer // P2 layer from the viewpoint of both easy adhesion and light resistance. In this case, as the resin used for the P11 layer and the P12 layer, those exemplified for the P1 layer can be preferably used.

(Easily adhesive layer (P2 layer))
The easy-adhesion sheet of this invention needs to provide P2 layer which becomes an easily-adhesive layer adjacent to P1 layer. At this time, the P2 layer needs to be provided on at least one side of the P1 layer. If the P2 layer serving as an easy adhesion layer is not provided in the sheet of the present invention, the desired easy adhesion property cannot be obtained.

  In the easy-adhesion sheet of the present invention, the easy-adhesion layer (P2 layer) is a layer formed from a polyamide resin A and a coating composition containing a crosslinking agent B, and the polyamide resin A in the coating composition It is necessary that the content is 50% by mass or more based on the solid content in the coating composition.

  The content of the polyamide resin A in the coating composition for forming the P2 layer of the present invention needs to be 50% by mass or more based on the solid content in the coating composition. When the content of the polyamide resin A is less than 50% by mass with respect to the solid content in the coating composition, the easy adhesion is not sufficient.

  Here, the polyamide resin in the present invention refers to a resin having an amide bond (—NHCO—) in the molecular skeleton, and specifically, an aliphatic polyamide resin composed of an aliphatic monomer and a part of an aromatic monomer. 3) ring-opening polymerization of a compound having a lactam skeleton, 4) polycondensation of an amino acid component having an amino group and a carboxyl group in one molecule, 5) a diamine component and a dicarboxylic acid component Can be obtained by polycondensation and combinations of 3) to 5).

  In 3), examples of the compound having a lactam skeleton include ε-caprolactam (nylon 6 (glass transition temperature = about 48 ° C. is obtained by ring-opening polymerization)), ω-undecane lactam (nylon 11 by ring-opening polymerization). (A glass transition temperature = about 37 ° C. is obtained), a compound having a lactam skeleton such as ω-laurolactam (nylon 12 (glass transition temperature = about 50 ° C. is obtained by ring-opening polymerization)), and the like. It is done.

  In 4), examples of amino acid components having an amino group and a carboxyl group in one molecule include ε-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

  In 5), examples of the diamine component include tetramethylene diamine, hexamethylene diamine, metaxylene diamine, undecamethylene diamine, dodecamethylene diamine, 1,2,2,4-tetramethylhexamethylene diamine, 2, 4 , 4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, m-xylylenediamine, p-xylylenediamine, 1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, bis-p- Aminocyclohexylmethane, 2,2-bis-p-aminocyclohexylpropane, isophoronediamine, and the like. Examples of dicarboxylic acid components include adipic acid, peric acid, azelaic acid, sepacic acid, dodecanoic acid, 1, 4-cyclohexanedicarboxylic acid 1,3-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, such as dimer acid.

  The polyamide resin A forming the P2 layer of the present invention is more preferably a polyamide resin that has been subjected to a modification treatment to exhibit solubility in order to impart applicability. Specifically, for example, by synthesizing an aliphatic polyamide in which an amide group (—NHCO—) is N-alkoxyalkylated, the intermolecular hydrogen bonding ability of the aliphatic polyamide can be inhibited to exhibit solubility. it can. Furthermore, it is preferable that the polyamide resin A is obtained by graft-polymerizing a hydrophilic monomer on the main chain of the polyamide in order to obtain affinity with water. Examples of the hydrophilic monomer include an anionic monomer having a carboxyl group, a sulfonic acid group, a phosphoric acid group, and a cationic monomer having a functional group such as a quaternary salt of an amino group. For example, acrylic acid, methacrylic acid, 2-trifluoromethyl acrylic acid, maleic acid and alkali metal salts of these acids, such as hydroxymethyl methacrylate, such as 2-acrylamido-2-methylpropane sulfonic acid, styrene sulfonic acid And alkali metal salts of these acids, such as acrylamide, N-alkylacrylamide (eg, N, N-dimethylacrylamide, N, N-dimethylaminopropylacrylamide, etc.), N, N-dimethylaminoethyl acrylate, N- Acryloylmorpholine N- vinyllactam (e.g., such as N- vinylpyrrolidone.) And the like.

  The P2 layer of the easy-adhesive sheet of the present invention is a layer formed from the coating composition containing the polyamide resin A, and is an ethylene-vinyl acetate copolymer generally used as a sealing material for solar cells. Excellent affinity with hot melt adhesives such as (EVA) and excellent easy adhesion. When using the easy-adhesion sheet of the present invention as a solar battery backsheet, the polyamide resin A is preferably an aliphatic polyamide resin from the viewpoint of excellent affinity with EVA. The polyamide resin A is preferably a polyamide resin having a glass transition temperature Tg of −50 ° C. or higher and 50 ° C. or lower by modification treatment or copolymerization, and more preferably the glass transition temperature Tg is −50 ° C. The polyamide resin has a temperature of 0 ° C. or lower, more preferably −30 ° C. or higher and −10 ° C. or lower. When the glass transition temperature Tg of the polyamide resin A is in the above range, it gives moderate flexibility to the P2 layer, and also increases the mobility during bonding, so that it has easy adhesion and long-term adhesion retention. It becomes possible to raise. Commercially available products can be used as the polyamide resin having the above glass transition temperature, for example, “AQ nylon” T-70 (glass transition temperature = −22 ° C.), P-95 (glass transition) manufactured by Toray Industries, Inc. (Point temperature = −46 ° C.), “Tresin” (registered trademark) FS-350E5AS manufactured by Nagase ChemteX Corporation can be preferably used.

  The coating composition for forming the P2 layer of the present invention needs to contain a crosslinking agent in order to enhance long-term adhesion retention. The cross-linking agent in the present invention refers to a compound or resin having reactivity that changes physical and chemical properties by linking molecular chains in the P2 layer by chemical bonds. In particular, a cross-linking agent having good reactivity with the polyamide resin A is preferable. By including a crosslinking agent in the coating composition forming the P2 layer, it reacts with the resin forming the P2 layer in the process of forming the P2 layer, thereby increasing the adhesiveness and long-term adhesion retention of the P2 layer. be able to.

  Specific examples of the crosslinking agent B contained in the coating composition forming the P2 layer in the present invention include melamine resin, epoxy resin, phenol resin, urea resin, isocyanate resin, oxazoline resin, amine resin, carbodiimide resin, and aziridine resin. Aldehyde resin and metal chelate resin. It is also preferable to use two or more of these crosslinking agents in combination.

  Examples of the melamine resin include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexaptoxymethyl melamine, hexapentyloxymethyl melamine, hexahexyloxymethyl melamine, and melamine resin.

  Examples of epoxy resins include N, N, N ′, N′-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, 1,6-hexane. Diol diglycidyl ether, neopentyl glycol diglycidyl ether, etherene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol poly Glycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether In addition to adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorching ricidyl ether, bisphenol-S-diglycidyl ether, two or more epoxy groups in the molecule The epoxy resin which has is mentioned.

  Examples of phenolic resins include p-cresol, m-cresol, o-cresol, 2,3-dimethylphenol, 2,4-dimethylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 3,4 -Dimethylphenol, 3,5-dimethylphenol, 2,3,4-trimethylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, 2,4,5-trimethylphenol, methylenebis p- Cresol, 2-methylresorcin, 4-methylresorcin, o-ethylphenol, m-ethylphenol, p-ethylphenol, 2,3-diethylphenol, 2,5-diethylphenol, p-isopropylphenol, cardanol, and these The modified body is mentioned.

  Examples of isocyanate resins include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, hexamethylene diisocyanate, diphenylmethane -4,4-diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, tetramethylxylylene diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, and their polyisocyanate compounds and trimethylol Examples include adducts with polyol compounds such as propane, burettes and isocyanurates of these polyisocyanate compounds.

  Examples of the amine resin include hexamethylenediamine, triethyldiamine, polyethyleneimine, hexamethylenetetraamine, diethylenetriamine, triethyltetraamine, isophoronediamine, and amino resin.

  Examples of aziridine resins include tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate, N, N′-hexamethylene-1.

  Examples of aldehyde resins include glyoxal, malondialdehyde, succindialdehyde, maleindialdehyde, glutardialdehyde, formaldehyde, acetaldehyde, and benzaldehyde.

  Examples of metal chelate resins include multimetallic acetylacetone and acetoacetyl ester coordination compounds such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, panadium, chromium and zirconium.

  A commercially available crosslinking agent can be obtained and used as the crosslinking agent B. For example, the isocyanate resin “Elastoron” (registered trademark) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., the phenolic resin “Register Top” manufactured by Gunei Chemical Industry Co., Ltd., the melamine resin “Beckamine” (registered trademark) manufactured by DIC Corporation, manufactured by Oshika Corporation Melamine resin “Oshika Resin”, Nippon Shokubai Co., Ltd. oxazoline resin “Epocross” (registered trademark), Nisshinbo Chemical Co., Ltd. carbodiimide resin “Carbodilite” (registered trademark), DIC Corporation epoxy resin “EPICLON” (registered trademark) , Epoxy resin “Denacol” (registered trademark) manufactured by Nagase ChemteX Corporation.

  As the crosslinking agent B contained in the coating composition for forming the P2 layer in the present invention, from the viewpoint of reactivity with the polyamide resin A and adhesiveness with the P1 layer, melamine resin, epoxy resin, phenol resin, urea resin Oxazoline resin and carbodiimide resin are preferable. Furthermore, it is more preferable that the coating composition for forming the P2 layer is a melamine resin and / or an epoxy resin from the viewpoint of coexistence with long-term adhesion retention. Moreover, when using a melamine resin and an epoxy resin together, it is preferable to set it as the range of 5: 1 to 1: 1 as a mixing mass ratio of the melamine resin and an epoxy resin in a coating composition, More preferably, it is 4: 1. The range is 2: 1.

  In the present invention, the mass ratio Wa: Wb of the polyamide resin A and the crosslinking agent B in the coating composition forming the P2 layer is preferably in the range of 50:50 to 95: 5, more preferably 60:40 to 90. : 10, more preferably in the range of 70:30 to 80:20. When the mass ratio Wa: Wb of the polyamide resin A and the crosslinking agent B forming the P2 layer in the present invention is less than 50:50, the polyamide resin component is insufficient and the easy adhesion property is reduced. There is. Moreover, when the ratio of the polyamide resin A to the mass ratio Wa: Wb of the polyamide resin A and the crosslinking agent B forming the P2 layer is larger than 95: 5, the crosslinking agent component is insufficient, and the strength of the P2 layer is insufficient. The winding property may be deteriorated.

In the easy-adhesive sheet of the present invention, the P2 layer is a layer formed from the coating composition containing the polyamide resin A and the cross-linking agent. When the easy-adhesive sheet of the present invention is mounted on a solar cell as a solar cell back sheet, for example, the solar cell can be made more durable. Various additives such as known heat stabilizers, lubricants, antistatic agents, anti-blocking agents, dyes, pigments, photosensitizers, surfactants, and UV absorbers may be added within a range that does not impair the effects of it can.

  For example, blocking at the time of winding can be prevented by adding silica particles as an anti-blocking agent to the P2 layer. Further, by adding a surfactant to the P2 layer, it is possible to increase the affinity of the coating liquid for the P1 layer and suppress coating unevenness.

In the present invention, the P2 layer is formed from a coating composition containing a polyamide resin A and a crosslinking agent B, and the content of the polyamide resin A in the coating composition is based on the solid content in the coating composition. By setting it as 50 mass% or more, it can be set as the sheet | seat which was excellent in adhesiveness.
The thickness of the P2 layer in the easy-adhesive sheet of the present invention is preferably 0.01 μm or more and 5 μm or less, more preferably 0.1 μm or more and 2.0 μm or less, and further preferably 0.5 μm or more and 1.5 μm or less. When the thickness of the P2 layer in the easy-adhesive sheet of the present invention is less than 0.01 μm, the easy-adhesiveness that is the object of the present invention may be insufficient. On the other hand, if the thickness of the P2 layer is greater than 5 μm, the reaction between the polyamide resin A and the crosslinking agent B becomes insufficient. As a result, the strength of the P2 layer is insufficient, the winding property is deteriorated due to insufficient drying, or the coating property. May get worse.

  The P2 layer of the present invention may have a laminated structure for the purpose of improving easy adhesion. For example, an anchor coat layer (referred to as P21 layer) having excellent adhesion with the P1 layer is provided in advance on one surface of the P1 layer, and a layer (referred to as P22 layer) that is further excellent in easy adhesion on the P21 layer. The providing method is also preferably used. In that case, the structure of the easy-adhesion sheet is laminated in the order of P1 layer // P21 layer / P22 layer, and the thickness of the P2 layer is represented by P21 layer + P22 layer. At this time, the P21 layer has good adhesiveness with the resin constituting the P1 layer and the P22 layer, and the P22 layer has good adhesiveness with the resin constituting the P21 layer and the EVA layer. There is no particular limitation as long as it is compatible with the EVA layer at the temperature during lamination. In this case, as the resin used for the P21 layer and the P22 layer, those exemplified for the P2 layer can be suitably used as appropriate.

  Next, an example is given and demonstrated about the manufacturing method of the easily bonding sheet | seat of this invention. This is an example, and the present invention should not be construed as being limited to the product obtained by such an example.

  First, the manufacturing method of the raw material which comprises P1 layer can be manufactured with the following method.

  The resin used as the raw material of the P1 layer of the present invention can be obtained by subjecting dicarboxylic acid or an ester derivative thereof and a diol to a transesterification reaction or an esterification reaction by a known method. Examples of conventionally known reaction catalysts include alkali metal compounds, alkaline earth metal compounds, zinc compounds, lead compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, titanium compounds, and phosphorus compounds. Preferably, an antimony compound, a germanium compound, or a titanium compound is preferably added as a polymerization catalyst at an arbitrary stage before the PET production method is completed. As such a method, for example, when a germanium compound is taken as an example, it is preferable to add the germanium compound powder as it is. In addition, in order to control the number average molecular weight of the polyester resin to 18500-40000, after polymerizing the polyester resin having a molecular weight of about 18000, the number average molecular weight is about 190 ° C. to a temperature below the melting point of the polyester resin. Thus, a so-called solid-phase polymerization method in which heating is performed under reduced pressure or a flow of an inert gas such as nitrogen gas is preferable. This method is preferably performed in that the number average molecular weight can be increased without increasing the terminal carboxyl group amount of the thermoplastic resin.

  Next, when the P1 layer has a single film configuration, the P1 layer manufacturing method is a method in which the P1 layer raw material is heated and melted in an extruder and extruded from a die onto a cast drum cooled (processed into a sheet). Method). As another method, the raw material for the P1 layer is dissolved in a solvent, and the solution is extruded from a die onto a support such as a cast drum or an endless belt to form a film, and then the solvent is dried and removed from the film layer. A method of processing into a shape (solution casting method) or the like can also be used.

  In addition, when the P1 layer has a laminated structure, when the material of each layer to be laminated is mainly composed of a thermoplastic resin, the two different thermoplastic resins are put into two extruders and melted to join. Thus, a method of co-extrusion onto a cast drum cooled from the die and processing it into a sheet (co-extrusion method) can be preferably used.

  Further, when a uniaxial or biaxially stretched sheet base material is selected as the laminate including the P1 layer and / or the P1 layer, as a manufacturing method thereof, first, an extruder (in the case of a laminated structure, a plurality of extruders) ), Melted and extruded from the die (co-extrusion in the case of a laminated structure), and cooled and solidified by static electricity on a cooled drum cooled to a surface temperature of 10 to 60 ° C. Make it.

  Next, this unstretched sheet is led to a group of rolls heated to a temperature of 70 to 140 ° C., and stretched 3 to 4 times in the longitudinal direction (longitudinal direction, that is, the traveling direction of the sheet). Cool with rolls.

  Subsequently, the both ends of the sheet are guided to a tenter while being gripped by clips, and are stretched 3 to 4 times in a direction (width direction) perpendicular to the longitudinal direction in an atmosphere heated to a temperature of 80 to 150 ° C.

  The stretching ratio is 3 to 5 times in each of the longitudinal direction and the width direction, and the area ratio (longitudinal stretching ratio x lateral stretching ratio) is preferably 9 to 15 times. When the area magnification is less than 9 times, the durability of the obtained biaxially stretched sheet becomes insufficient, and conversely, when the area magnification exceeds 15 times, there is a tendency that tearing tends to occur.

  As the biaxial stretching method, in addition to the sequential biaxial stretching method in which the stretching in the longitudinal direction and the width direction is separated as described above, the simultaneous biaxial stretching method in which the stretching in the longitudinal direction and the width direction is performed simultaneously. Either one does not matter.

  The method for forming the P2 layer on the P1 layer in the easy-adhesive sheet of the present invention is not particularly limited, but it is preferable to use a coating technique. As a coating method, a known method can be applied, and for example, a roll coating method, a dip coating method, a bar coating method, a die coating method, a gravure roll coating method, or a combination of these methods can be used. it can. Among them, the bar coating method is preferable from the viewpoint of a wide selection range of the coating agent, while the die coating method and the gravure roll coating method can be preferably selected from the viewpoint of thick film coating property when it is desired to increase the thickness of the P2 layer.

  Furthermore, the formation of the P2 layer is more preferably performed by in-line coating provided in the manufacturing process of the P1 layer from the viewpoint of process simplification. Specifically, after the uniaxially stretched sheet in the case of the sequential biaxial stretching method, the coating step is provided after the unstretched sheet or the unstretched sheet in the case of the simultaneous biaxial stretching method, respectively. After the coating composition for forming the layer is applied, the P1 layer is thermally fixed simultaneously with the drying process of the coating composition. At this time, the drying temperature of the coating composition is preferably 150 ° C. or higher and 250 ° C. or lower, more preferably 170 ° C. or higher and 230 ° C. or lower, more preferably, from the viewpoint of achieving both the heat dimensional stability of the base material layer P1 and the wet heat resistance. It is 180 degreeC or more and 220 degrees C or less.

  If necessary, from the viewpoint of improving the wettability of the coating composition to the P1 layer and improving the interlayer adhesion after forming the P2 layer, the surface of the base material layer P1 may be subjected to corona treatment immediately before the coating step. .

  Examples of the solvent for the coating composition for forming the P2 layer in the easy-adhesive sheet of the present invention include toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dimethylformamide, and dimethylacetamide. , Methanol, ethanol, and water, and the properties of the coating liquid may be either an emulsion type or a dissolution type. In recent years, emphasis has been placed on environmental protection, resource saving, exhaust problems of organic solvents during production, etc., and a dissolved or emulsion type coating liquid mainly composed of water is the preferred form. In addition, the method for emulsifying the polyamide resin A and the crosslinking agent B contained in the coating composition for forming the P2 layer is not particularly limited, and is widely used by those skilled in the art as a solid / liquid stirring device or an emulsifier. It can be produced by a known device.

  The easy-adhesion sheet of this invention can be manufactured with the said manufacturing method. The obtained easy-adhesion sheet has excellent performance. The easy-adhesive sheet of the present invention can be suitably used as an industrial material application such as a solar battery back sheet, a process sheet, and an adhesive tape, or as an easy-adhesive base material application such as extrusion lamination and thermal lamination, taking advantage of its features. In addition, when using the easily bonding sheet | seat of this invention for the easily bonding base material use of extrusion lamination, it is preferable that the resin to carry out extrusion lamination is the said polyamide resin, and can obtain more excellent adhesiveness.

  The solar cell of the present invention is characterized by using the above easy-adhesive sheet. By using the easy-adhesion sheet as a solar battery back sheet, it becomes possible to enhance the durability as compared with the conventional solar battery. An example of the configuration is shown in FIG. 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, a transparent substrate 4 such as glass, and an easy-adhesive sheet 1 However, the present invention is not limited to this, and any structure can be used. Although FIG. 1 shows an example of a single easy-adhesive sheet, it is also possible to use a composite sheet in which an easy-adhesive sheet and another film are bonded to each other according to other required characteristics.

  Here, in the solar cell of the present invention, the easy-adhesion sheet 1 plays a role of protecting the power generation cell installed on the back surface of the sealing material 2 that seals the power generation element. Here, the easy-adhesion sheet needs to be arranged so that the P2 layer is in contact with the sealing material 2. By adopting this configuration, the durability of the solar cell can be improved by protecting the power generation cell for a long period of time even when exposed to the outdoors, taking advantage of the excellent easy adhesion of the present invention.

  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, tetrafluoroethylene-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 resin, olefinic 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. Moreover, in order to give these substrates the adhesiveness with EVA resin etc. which are the sealing materials of an electric power generation element, it is also preferably performed to give the surface a corona treatment, a plasma treatment, an ozone treatment, and an easy adhesion treatment. .

  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 easy-adhesion sheet of the present invention into a solar cell system, it becomes possible to enhance the durability as compared with conventional solar cells. 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.

[Measurement method and evaluation method of characteristics]
(1) Glass transition temperature Tg of polyamide resin A
Differential scanning calorific value obtained when the temperature was raised from −100 ° C. to 100 ° C. in a differential scanning calorimetry (hereinafter referred to as DSC) at a rate of temperature increase of 20 ° C./min by a method based on JIS K-7121 (1999). The glass transition temperature Tg in the measurement chart was determined. In addition, when a glass transition temperature is not observed in said range, it measures by changing a measurement temperature range.

(2) Polymer properties (2-1) Intrinsic viscosity IV
A measurement sample (polyester resin (raw material) or polyester film) is dissolved in 100 ml of orthochlorophenol (solution concentration C (measurement sample weight / solution volume) = 1.2 g / ml), and the viscosity of the solution at 25 ° C. is measured. Measured using an Ostwald viscometer. Similarly, the viscosity of the solvent was measured. [Η] was calculated by the following formula (4) using the obtained solution viscosity and solvent viscosity, and the obtained value was defined as the intrinsic viscosity (IV).
ηsp / C = [η] + K [η] ² · C (4)
(Where ηsp = (solution viscosity / solvent viscosity) −1, K is the Huggins constant (assuming 0.343))
In addition, when there existed insoluble matters, such as an inorganic particle, in the solution which dissolved the polyester resin (raw material) or the polyester film, it measured using the following method.
i) A measurement sample (polyester resin (raw material) or polyester film) is dissolved in 100 mL of orthochlorophenol to prepare a solution having a solution concentration higher than 1.2 mg / mL. Here, let the weight of the measurement sample used for orthochlorophenol be a measurement sample weight.
ii) Next, the solution containing the insoluble matter is filtered, and the weight of the insoluble matter and the volume of the filtrate after filtration are measured.
iii) Adding orthochlorophenol to the filtrate after filtration, (measurement sample weight (g) −insoluble matter weight (g)) / (volume of filtrate after filtration (mL) + volume of orthochlorophenol added) (ML)) is adjusted to 1.2 g / 100 mL.
(For example, when a concentrated solution having a measurement sample weight of 2.0 g / solution volume of 100 mL was prepared, the weight of insoluble matter when the solution was filtered was 0.2 g, and the filtrate volume after filtration was 99 mL Adjust to add 51 mL of orthochlorophenol ((2.0 g-0.2 g) / (99 mL + 51 mL) = 1.2 g / mL))
iv) Using the solution obtained in iii), the viscosity at 25 ° C. is measured using an Ostwald viscometer, and the obtained solution viscosity and solvent viscosity are used to calculate [η] according to the above formula (C). And the obtained value is taken as the intrinsic viscosity (IV).

(2-2) Amount of terminal carboxyl group (in the table, described as COOH amount)
The amount of terminal carboxyl groups in the P1 layer was measured by the following method according to the method of Malice. (Document M. J. Malice, F. Huizinga, Anal. Chim. Acta, 22 363 (1960)).
2 g of a measurement sample (polyester resin (raw material) or polyester film) was dissolved in 50 mL of o-cresol / chloroform (weight ratio 7/3) at a temperature of 80 ° C., and titrated with a 0.05 N KOH / methanol solution to obtain a terminal carboxyl. The base concentration was measured and indicated as equivalent / polyester 1t. In addition, the indicator at the time of titration used phenol red, and the place where it changed from yellowish green to light red was set as the end point of titration. If there is insoluble matter such as inorganic particles in the solution in which the polyester resin (raw material) or polyester film is dissolved, the solution is filtered to measure the weight of the insoluble matter, and the weight of the insoluble matter is subtracted from the measured sample weight. Correction was performed with the measured value as the measured sample weight. Moreover, the value obtained using a polyester film as a measurement sample was made into the value of the polyester resin which comprises a polyester film.

(3) Thickness of P1 layer and P2 layer Using a microtome, a small piece cut in a direction perpendicular to the surface of the solar cell back surface protection sheet was prepared, and the cross section was taken as a field emission scanning electron microscope “JSM-6700F” (JEOL Co., Ltd.) was used to magnify and photograph 3000 times. From the cross-sectional photograph, the thickness of each of the P1 layer and the P2 layer was measured, and the thickness was obtained by calculating back from the magnification. In addition, the thickness used the cross-sectional photograph of five places arbitrarily selected from the mutually different measurement visual field, and used the average value.

(4) Adhesive evaluation Based on JIS K 6854-2 (1999 edition), adhesiveness was evaluated from the peeling strength with the EVA sheet | seat which is a hot-melt-adhesive, and the P2 layer side in the sheet | seat of an Example and a comparative example. The measurement test piece is a 500 μm thick EVA sheet (vinyl acetate copolymerization ratio: 28 mol%) on a semi-tempered glass having a thickness of 3 mm, and the P2 layer side of the sheet of the example and the comparative example is the EVA sheet side. A layer obtained by press treatment using a commercially available vacuum laminator under 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 was used. The peel strength test is performed at 180 ° peel, the width of the test piece is 10 mm, two test pieces are prepared, the place is changed for each test piece, the measurement is performed at three places, and the average value of the obtained measurement values is peeled off The value of strength was used, and the easy adhesion was determined as follows.

In addition, when the sheet | seat of this invention fractured | ruptured before peeling at an interface in this measurement, the measured value at the time of the fracture | rupture was made into the value of peeling strength.
When the peel strength is 40 N / 10 mm or more: A
When the peel strength is 20 N / 10 mm or more and less than 40 N / 10 mm: B
When the peel strength is 10 N / 10 mm or more and less than 20 N / 10 mm: C
When peel strength is less than 10 N / 10 mm: D
As for easy adhesion, A to C are good, and among them, A is the best.

(5) Moisture and heat resistance evaluation After the sheets of Examples and Comparative Examples were cut into a measurement piece shape of 10 mm × 200 mm, using a pressure cooker manufactured by Tabai Espec Co., Ltd., under the conditions of a temperature of 125 ° C. and a relative humidity of 100% RH. After that, the elongation at break was measured based on ASTM-D882 (1997). In addition, the measurement was performed between the chucks of 50 mm, the pulling speed of 300 mm / min, and the number of times of measurement n = 5.

Further, the sheet before treatment was cut into a size of 10 mm × 200 mm, and the breaking elongation E0 was measured. Using the obtained breaking elongations E0 and E1, the elongation retention was calculated according to the following formula (1), and the treatment time at which the elongation retention was 50% was defined as the elongation half-life.
Elongation retention (%) = E1 / E0 × 100 (1)
From the obtained elongation half-life, the moisture and heat resistance of the sheet was determined as follows.
When the elongation half-life is 60 hours or more: A
When the elongation half-life is 40 hours or more and less than 60 hours: B
When the elongation half-life is 30 hours or more and less than 40 hours: C
When the elongation half-life is less than 30 hours: D
As for the heat and moisture resistance, A to C are good, and among them, A is the best.

(6) Durability of solar cell (6-1) Preparation of solar cell Flux H722 manufactured by HOZAN was applied to the front and back silver electrode portions of solar cell Q6LPT-G2 manufactured by Qcells using a dispenser, and the front and back surfaces A copper foil SSA-SPS0.2 × 1.5 (20) manufactured by Hitachi Cable Co., Ltd. as a wiring material cut to a length of 155 mm on the silver electrode is 10 mm away from one end of the cell on the surface side. Then, the back side was placed symmetrically with the front side, and a soldering iron was brought into contact with the solder back side using a soldering iron, and the front and back sides were soldered simultaneously to produce one cell string.

  Placed so that the longitudinal direction of the copper foil A-SPS 0.23 × 6.0 made by Hitachi Cable Co., Ltd. is perpendicular to the longitudinal direction of the wiring material protruding from the cell of the produced 1-cell string and the extraction electrode cut into 180 mm, The flux was applied to the portion where the wiring material and the take-out electrode overlapped, and solder welding was performed to produce strings with the take-out electrode.

  Next, 190 mm × 190 mm 3.2 mm thick white plate heat-treated glass for solar cells manufactured by Asahi Glass Co., Ltd., 190 mm × 190 mm 500 μm thick EVA sheet (vinyl acetate copolymerization ratio: 28 mol%), prepared strings with extraction electrodes, 190 mm × 190 mm of 500 μm thick EVA sheet, each of the laminated sheets of Examples and Comparative Examples cut out to 190 mm × 190 mm are sequentially stacked, and the glass is set so as to be in contact with the heating plate of the vacuum laminator. Vacuum lamination was performed under the conditions of vacuuming 4 minutes, pressing 1 minute, and holding time 10 minutes. At this time, the strings with extraction electrodes were set so that the glass surface was on the cell surface side.

(6-2) Durability of solar cell (long-term adhesion retention of easy-adhesive sheet) Evaluation Ten solar cells prepared in (6-1) were prepared and adjusted to 85 ° C. and 85% RH. After processing for 1000 hours in a constant temperature and humidity chamber made by ESPEC, it was visually confirmed whether or not peeling occurred in each laminated sheet of the laminated examples and comparative examples. The durability of the solar cell (long-term adhesion retention of the easy-adhesive sheet) is determined as follows with respect to how many of the 10 solar cells are visually peeled. It was.
When peeling does not occur in all solar cells: A
When 1 to 5 sheets of the produced solar cells are peeled from the solar cell: B
When 6 or more sheets of the produced solar cells are peeled from the solar cells: D
As for the durability of the solar cell (long-term adhesion retention of the easy-adhesive sheet), A and B are excellent, and among them, A is the most excellent.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not necessarily limited to these.

(Polyester resin raw material)
1. PET raw material A (used for Examples 1-14, 16, 18-22)
A polycondensation reaction was performed using 100 parts by mass of terephthalic acid as the dicarboxylic acid component, 100 parts by mass of ethylene glycol as the diol component, and magnesium acetate, antimony trioxide, and phosphorous acid as the catalyst. Next, the obtained polyethylene terephthalate was dried and crystallized at 160 ° C. for 6 hours, and then subjected to solid phase polymerization at 220 ° C. and a vacuum degree of 0.3 Torr for 9 hours to have a melting point of 255 ° C. and an intrinsic viscosity of 0.80 dl / g. A polyethylene terephthalate raw material (PET-A) having a terminal carboxyl group amount of 10 equivalents / ton was obtained.

2. PET raw material B (used in Example 15)
A polycondensation reaction was performed using 100 parts by mass of terephthalic acid as the dicarboxylic acid component, 100 parts by mass of ethylene glycol as the diol component, and magnesium acetate, antimony trioxide, and phosphorous acid as the catalyst. Next, the obtained polyethylene terephthalate was dried and crystallized at 160 ° C. for 6 hours to obtain a polyethylene terephthalate raw material (PET-B) having a melting point of 255 ° C., an intrinsic viscosity of 0.65 dl / g, and a terminal carboxyl group content of 25 equivalents / ton. It was.

3. PEN raw material (used in Example 15)
To a mixture of 100 parts by mass of dimethyl 2,6-naphthalenedicarboxylate and 60 parts by mass of ethylene glycol, 0.03 parts by mass of manganese acetate tetrahydrate salt is added and gradually increased from a temperature of 150 ° C. to a temperature of 240 ° C. The transesterification was carried out while raising the temperature. In the middle, when the reaction temperature reached 170 ° C., 0.024 parts by mass of antimony trioxide was added. When the reaction temperature reached 220 ° C., 0.042 parts by mass of 3,5-dicarboxybenzenesulfonic acid tetrabutylphosphonium salt was added. Thereafter, a transesterification reaction was carried out, and 0.023 parts by mass of trimethyl phosphoric acid was added. Next, the reaction product is transferred to a polymerization apparatus, heated to a temperature of 290 ° C., subjected to a polycondensation reaction under a high vacuum of 30 Pa, and the stirring torque of the polymerization apparatus is a predetermined value (specifically depending on the specifications of the polymerization apparatus). Although this value was different, the value indicated by polyethylene-2,6-naphthalate having an intrinsic viscosity of 0.65 in this polymerization apparatus was a predetermined value). Next, the obtained polyethylene terephthalate was dried and crystallized at 160 ° C. for 6 hours, followed by solid phase polymerization at 220 ° C. and a vacuum degree of 0.3 Torr for 9 hours, melting point 255 ° C., intrinsic viscosity 0.70 dl / g. A polyethylene naphthalate raw material (PEN) having a terminal carboxyl group attachment amount of 25 equivalents / ton was obtained.

4). PET raw material A-based titanium oxide master (used in Examples 1 to 13 and 18 to 22)
Above 1. 100 parts by mass of PET resin (PET-A) obtained according to the above and 100 parts by mass of rutile-type titanium oxide particles having an average particle size of 210 nm are melt-kneaded in a vented 290 ° C. extruder, and a titanium oxide-containing polyethylene terephthalate raw material the (PETa-TiO ₂₎ was prepared.

5. PET raw material B base titanium oxide master (used in Example 17)
2. 100 parts by mass of PET resin (PET-B) obtained according to the above and 100 parts by mass of rutile-type titanium oxide particles having an average particle diameter of 210 nm are melt-kneaded in a vented 290 ° C. extruder, and a titanium oxide-containing polyethylene terephthalate raw material the (PETb-TiO ₂₎ was prepared.

6). PEN raw material-based titanium oxide master (used in Example 15)
4. above. 100 parts by mass of the PEN resin obtained according to the above and 100 parts by mass of rutile titanium oxide particles having an average particle diameter of 210 nm are melt-kneaded in a vented 300 ° C. extruder, and a titanium oxide-containing polyethylene naphthalate raw material (PEN-TiO ₂ ) was produced.

7). PET raw material A base carbon particle master (used in Example 16)
Above 1. 100 parts by mass of PET resin (PET-A) obtained according to the above and 11 parts by mass of carbon particles having an average particle diameter of 40 nm were melt-kneaded in a vented 290 ° C. extruder, and the carbon particle-containing polyethylene terephthalate raw material (PETa- CB) was prepared.

(Preparation of easy adhesive layer coating)
After preparing coating agents A to T using water as a diluent solvent and the coating materials described in the following section, acetylene diol surfactant “Orphine” (registered trademark) EXP4051F manufactured by Nissin Chemical Co., Ltd. It mix | blended so that it might become a ratio of 0.25 mass% with respect to the coating agent. The blending amounts of the paints described in the following items are all solid content ratios.

1. Coating agents A to E (used in Examples 1 to 5 and 14 to 18)
After mixing “AQ Nylon” T-70 manufactured by Toray Industries, Ltd. as polyamide resin A and melamine resin “Oshika Resin” MG200 manufactured by Oshika Co., Ltd. as cross-linking agent B so that the solid content ratios shown in Tables 1 and 2 are obtained, the solid content It diluted with the pure water so that a density | concentration might be 17 mass%, and coating agent AE was obtained.

2. Coating agent F (used in Example 6)
A coating agent F was obtained in the same manner as the coating agent C except that “AQ nylon” P-95 manufactured by Toray Industries, Inc. was used as the polyamide resin A.

3. Coating agent G (used in Example 7)
A coating agent G was obtained in the same manner as the coating agent C, except that the polyamide resin A used was a mixture of “AQ nylon” P-95 and A-90 manufactured by Toray Industries, Inc. at a weight ratio of 1: 1. Since A-90 is in the form of pellets, the pellets are mixed in pure water kept at 50 ° C. so that the solid content concentration is 50% by mass or less, left to stand for 2 hours or more, dissolved, and then stirred. While stirring, the solution was cooled to room temperature and used as an aqueous solution.

4). Coating agent H (used in Example 8)
A coating agent H was obtained in the same manner as the coating agent C except that only “AQ nylon” A-90 manufactured by Toray Industries, Inc. was used as the polyamide resin A.

5. Coating I (used in Example 9)
Coating agent I was obtained in the same manner as coating agent C except that melamine resin “Beccamin” (registered trademark) PM-80 manufactured by DIC Corporation was used as crosslinking agent B.

6). Coating agent J (used in Example 10)
Coating agent J was obtained in the same manner as coating agent C, except that the epoxy resin “Denacol” (registered trademark) EX-741 manufactured by Nagase ChemteX Corporation was used as the crosslinking agent B.

7). Coating agent K (used in Example 11)
Coating agent K was obtained in the same manner as coating agent C, except that Nisshinbo Chemical Co., Ltd. carbodiimide resin “Carbodilite” (registered trademark) V-04 was used as crosslinking agent B.

8). Coating agent L (used in Example 12)
As a crosslinking agent B, except that a mixture of melamine resin “Oshika Resin” MG200 manufactured by Oshika Co., Ltd. and epoxy crosslinking agent “Denacol” (registered trademark) EX-741 manufactured by Nagase ChemteX Corporation in a weight ratio of 3: 1 was used. Obtained Coating L in the same manner as Coating C.

9. Coating agent M (used in Example 13)
As a cross-linking agent B, a mixture of melamine resin “Oshika Resin” MG200 manufactured by Oshika Co., Ltd. and epoxy cross-linking agent “Denacol” (registered trademark) EX-741 manufactured by Nagase ChemteX Co., Ltd. in a weight ratio of 1: 1 was used. Obtained Coating M in the same manner as Coating C.

10. Coating agent N (used in Examples 19 and 20)
A coating agent N was obtained in the same manner as the coating agent C, except that dilution with pure water was performed so that the solid content concentration was 3% by mass.

11. Coating agent O (used in Examples 21 and 22)
Coating agent O was obtained in the same manner as coating agent C, except that dilution with pure water was performed so that the solid content concentration was 45% by mass.

12 Coating agent P (used in Comparative Example 2)
Using only “AQ Nylon” T-70 manufactured by Toray Industries, Inc. as the polyamide resin A, it was diluted with pure water to a solid content concentration of 17% by mass, and a coating agent P was obtained.

13. Coating Q (used in Comparative Example 3)
Using only melamine resin “Oshika Resin” MG200 manufactured by Oshika Co., Ltd. as the cross-linking agent B, it was diluted with pure water so as to have a solid content concentration of 17% by mass to obtain a coating material Q.

14 Coating agent R (used in Comparative Example 4)
After mixing “AQ Nylon” T-70 manufactured by Toray Industries, Inc. as polyamide resin A and melamine resin “Oshika Resin” MG200 manufactured by Oshika Co., Ltd. as cross-linking agent B so that the solid content ratio shown in Table 3 is obtained, the solid content concentration is Dilution with pure water was carried out so that it might become 17 mass%, and coating agent R was obtained.

15. Coating agent S (used in Comparative Example 5)
After mixing the polyester resin “Pesresin” TR620K manufactured by Takamatsu Yushi Co., Ltd. and the melamine resin “Oshika Resin” MG200 manufactured by Oshika Co., Ltd. as the crosslinking agent B so as to have the solid content ratio shown in Table 3, instead of the polyamide resin, the solid content concentration Was diluted with pure water so as to be 17% by mass to obtain a coating agent S.

16. Coating agent T (used in Comparative Example 6)
Instead of polyamide resin, acrylic resin “Nicazole” (registered trademark) RX7013ED manufactured by Nippon Carbide Industries Co., Ltd. and melamine resin “Oshika Resin” MG200 manufactured by Oshika Co., Ltd. as a cross-linking agent B were mixed so as to have a solid content ratio shown in Table 3. Then, it diluted with the pure water so that solid content concentration might be 17 mass%, and the coating agent T was obtained.

(Examples 1 to 13)
PET raw material A (PET-A) vacuum-dried at 180 ° C. for 2 hours and PET raw material A-based titanium oxide master (PETa-TiO ₂ ) were blended so that the amount of particles was the concentration shown in Table 1, and in an extruder at 280 ° C. And kneaded and introduced into a T die die. Subsequently, it was melt-extruded into a sheet form from a T-die die and adhered and cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched sheet. Subsequently, after preheating the unstretched sheet with a roll group heated to a temperature of 80 ° C., a three-fold speed difference is created between the roll heated to a temperature of 88 ° C. and the roll adjusted to a temperature of 25 ° C. After stretching 3 times in the longitudinal direction (longitudinal direction), it was cooled with a roll group at a temperature of 25 ° C. to obtain a uniaxially stretched sheet. After the uniaxially stretched sheet was subjected to corona treatment, a coating agent corresponding to the example numbers shown in Table 1 was applied with a # 8 metering bar.

  While holding both ends of the obtained uniaxially stretched sheet with a clip, the tenter is guided to a preheating zone at a temperature of 80 ° C. in the tenter, and then continuously heated at 90 ° C. in a direction perpendicular to the longitudinal direction (width direction). The film was stretched 3.2 times. Subsequently, heat treatment was performed at 220 ° C. for 20 seconds in a heat treatment zone in the tenter, and further relaxation treatment was performed in the 4% width direction at 220 ° C. Then, it was gradually cooled to obtain a biaxially stretched sheet having a P1 layer thickness of 100 μm and a P2 layer easy-adhesion layer thickness of 0.6 μm. Table 1 shows the intrinsic viscosity IV and the terminal carboxyl group content measured by separating the P1 layer from the obtained sheet.

  The resulting sheet was evaluated for characteristics. As a result, as shown in Table 1, it is a sheet having good adhesiveness, and in particular, it is T-70 as polyamide resin A and melamine resin or melamine resin and epoxy resin are mixed at a ratio of 3: 1 as crosslinking agent B. It was found that Examples 3, 9, and 12 were mixed with a solid content ratio of 75:25 to have excellent excellent adhesive properties. Moreover, it was found that all of the obtained sheets have excellent moisture and heat resistance. Furthermore, the solar cell carrying the obtained sheet | seat was produced and the durability evaluation of the solar cell was implemented. As a result, it was found that all the solar cells have excellent durability. In particular, it was found that the solar cells on which the sheets of Examples 3, 9, and 12 were mounted had very excellent durability.

(Example 14)
A biaxially stretched sheet was obtained in the same manner as in Example 3 except that only PET raw material A (PET-A) was used for the P1 layer.

  The obtained sheet was found to have very excellent easy adhesion equivalent to that of Example 3 and very excellent moisture and heat resistance. Furthermore, it was found that the solar cell on which the obtained sheet is mounted has very excellent durability.

(Example 15)
A biaxially stretched sheet was obtained in the same manner as in Example 3 except that a PEN raw material (PEN) and a PEN-based titanium oxide master (PEN-TiO ₂ ) were used for the P1 layer.

Although the obtained sheet was inferior to Example 3, it was found to have excellent easy-adhesion properties and very excellent heat and humidity resistance. Furthermore, it turned out that the solar cell carrying the obtained sheet | seat has the outstanding durability.
(Example 16)
A biaxially stretched sheet was obtained in the same manner as in Example 3 except that PET raw material A (PET-A) and PET raw material A base CB master (PETa-CB) were used for the P1 layer.

  The obtained sheet was found to have very excellent easy adhesion equivalent to that of Example 3 and excellent moisture and heat resistance. Furthermore, it was found that the solar cell on which the obtained sheet is mounted has very excellent durability.

(Example 17)
A biaxially stretched sheet was obtained in the same manner as in Example 3 except that PET raw material B (PET-B) and PET raw material B-based titanium oxide master (PETb-TiO ₂ ) were used for the P1 layer.

  The obtained sheet was found to have a very excellent easy-adhesive property equivalent to that of Example 3 and in a range with no problem although the heat-and-moisture resistance was slightly inferior. Furthermore, it was found that the solar cell on which the obtained sheet is mounted has very excellent durability.

(Example 18)
In the P1 layer, the PET raw material A (PET-A) and the PET raw material A-based titanium oxide master (PETa-TiO ₂ ) were mixed separately so that the P11 layer and the P12 layer had the particle amounts shown in Table 2. The raw materials were melted and kneaded separately by two extruders, introduced into the T die die through the feed block from the two extruders to obtain a P11 / P12 laminated sheet, and the biaxial as in Example 3. A stretched sheet was obtained. At this time, the rotational speeds of the two extruders were adjusted so that the stacking ratio of P11 / P12 was 7/1.

  The obtained sheet was found to have very excellent easy adhesion equivalent to that of Example 3 and very excellent moisture and heat resistance. Furthermore, it was found that the solar cell on which the obtained sheet is mounted has very excellent durability.

(Examples 19 to 22)
In the P2 layer, the coating material corresponding to the number of the example among the coating materials described in Table 2, # 19 is a metalling bar in Example 19, # 20 is in Examples 20, 21 and # 15 is a metalling bar in Example 22. A biaxially stretched sheet was obtained in the same manner as in Example 3 except that the thickness of P2 layer shown in Table 2 was applied.

  The resulting sheet was evaluated for characteristics. As a result, as shown in Table 2, Examples 19 and 20 in which the thickness of the P2 layer was thinner than that of Example 3 were inferior in easy-adhesiveness but were in the range of no problem, and the thickness of the P2 layer was implemented. Although Examples 21 and 22 which were thicker than Example 3 had very excellent easy adhesion equivalent to Example 3, application lines were visually confirmed. Furthermore, it turned out that the solar cell carrying the obtained sheet | seat has the outstanding durability.

(Comparative Example 1)
PET raw material A (PET-A) vacuum-dried at 180 ° C. for 2 hours and PET raw material A-based titanium oxide master (PETa-TiO ₂ ) were prepared so that the amount of particles was the concentration shown in Table 3, and in an extruder at 280 ° C. And kneaded and introduced into a T die die. Subsequently, it was melt-extruded into a sheet form from a T-die die and adhered and cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched sheet. Subsequently, after preheating the unstretched sheet with a roll group heated to a temperature of 80 ° C., a three-fold speed difference is created between the roll heated to a temperature of 88 ° C. and the roll adjusted to a temperature of 25 ° C. After stretching 3 times in the longitudinal direction (longitudinal direction), it was cooled with a roll group at a temperature of 25 ° C. to obtain a uniaxially stretched sheet. While holding both ends of the obtained uniaxially stretched sheet with a clip, the tenter is guided to a preheating zone at a temperature of 80 ° C. in the tenter, and then continuously heated at 90 ° C. in a direction perpendicular to the longitudinal direction (width direction). The film was stretched 3.2 times. Subsequently, heat treatment was performed at 220 ° C. for 20 seconds in a heat treatment zone in the tenter, and further relaxation treatment was performed in the 4% width direction at 220 ° C. Subsequently, it was uniformly cooled slowly to obtain a biaxially stretched sheet without a P2 layer.

  When the obtained sheet was subjected to characteristic evaluation, it was found that the easy adhesion was inferior. Furthermore, it turned out that durability is inferior also about the solar cell carrying the obtained sheet | seat.

(Comparative Examples 2-6)
As shown in Table 3, instead of the coating agent P not containing the crosslinking agent B, the coating agent Q not containing the polyamide resin A, the coating agent R in which the solid content ratio of the polyamide resin A and the crosslinking agent B is 45:55, and the polyamide resin A biaxially stretched sheet was obtained in the same manner as in Example 3 except that the coating agent S using a polyester resin and the coating agent T using an acrylic resin instead of the polyamide resin were applied.

  When the obtained sheet was subjected to characteristic evaluation, it was found that all the sheets had poor easy adhesion. Furthermore, it turned out that durability is inferior also about the solar cell carrying the obtained sheet | seat.

  The easy-adhesive sheet of the present invention can be suitably used as an industrial material application such as a solar battery back sheet, a process sheet, and an adhesive tape, and an easy-adhesive substrate application such as extrusion lamination and heat lamination. Moreover, the solar cell excellent in durability can be provided by mounting this easily bonding sheet in a solar cell as a solar cell backsheet.

1: Solar cell back sheet 2: Sealing material 3: Power generation element 4: Transparent substrate

Claims (9)

Easily having a base material layer (P1 layer) made of a polyester resin composition and a layer (P2 layer) satisfying the following requirements (1) and (2) adjacent to at least one side of the P1 layer Adhesive sheet.
(1) The P2 layer is a layer formed from a coating composition containing a polyamide resin A and a crosslinking agent B.
(2) The content of the polyamide resin A in the coating composition is 50% by mass or more based on the solid content in the coating composition. The easy-adhesion sheet according to claim 1, wherein the polyamide resin A has a glass transition temperature Tg of −50 ° C. or more and 0 ° C. or less. The easily adhesive sheet according to claim 1 or 2, wherein the crosslinking agent B is a melamine resin and / or an epoxy resin. The sheet according to any one of claims 1 to 3, wherein the P2 layer has a thickness of 0.1 µm or more and 2.0 µm or less. The P2 layer is a layer formed by applying a coating composition containing a polyamide resin A and a crosslinking agent B to the P1 layer and then performing a heat treatment at 150 ° C. or higher and lower than 250 ° C. Item 5. The easy-adhesive sheet according to any one of Items 1 to 4. 2. The polyester resin constituting the P1 layer is polyethylene terephthalate having an intrinsic viscosity IV of 0.65 dl / g or more and 0.80 dl / g or less and a terminal carboxyl group amount of 25 equivalents / ton or less. The easily adhesive sheet in any one of -5. It uses as an easily bonding sheet, The easily bonding sheet in any one of Claims 1-6 characterized by the above-mentioned. It uses as a solar cell backsheet, The easily adhesive sheet in any one of Claims 1-6 characterized by the above-mentioned. The solar cell using the easily bonding sheet | seat of Claim 8.

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