WO2012096217A1 - Solar-cell back-side protective sheet - Google Patents

Solar-cell back-side protective sheet Download PDF

Info

Publication number
WO2012096217A1
WO2012096217A1 PCT/JP2012/050115 JP2012050115W WO2012096217A1 WO 2012096217 A1 WO2012096217 A1 WO 2012096217A1 JP 2012050115 W JP2012050115 W JP 2012050115W WO 2012096217 A1 WO2012096217 A1 WO 2012096217A1
Authority
WO
WIPO (PCT)
Prior art keywords
functional group
reactive functional
film
layer
base film
Prior art date
Application number
PCT/JP2012/050115
Other languages
French (fr)
Japanese (ja)
Inventor
市村　茂樹
武俊 岩佐
高橋　章
榮一 杉本
Original Assignee
日本発條株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日本発條株式会社 filed Critical 日本発條株式会社
Publication of WO2012096217A1 publication Critical patent/WO2012096217A1/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/20—Layered products comprising a layer of metal comprising aluminium or copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/048—Encapsulation of modules
    • H01L31/0481—Encapsulation of modules characterised by the composition of the encapsulation material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/048—Encapsulation of modules
    • H01L31/049—Protective back sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2255/00—Coating on the layer surface
    • B32B2255/06—Coating on the layer surface on metal layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2255/00—Coating on the layer surface
    • B32B2255/26—Polymeric coating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/712—Weather resistant
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/724—Permeability to gases, adsorption
    • B32B2307/7242—Non-permeable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/12—Photovoltaic modules
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/008—Additives improving gas barrier properties
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
    • C09D183/10—Block or graft copolymers containing polysiloxane sequences
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • the present invention has an excellent weather resistance and an excellent water vapor barrier resistance, and there is some thermal distortion and bending associated with the assembly of hot press molding and vacuum / pressure molding when manufacturing solar cell panels.
  • the present invention also relates to a solar cell back surface protective sheet having flexibility that does not impair the water vapor gas barrier property.
  • back surface protection sheets constituting solar cell modules.
  • a sheet in which films having different characteristics are laminated with an adhesive and multilayered is mainly used as a device for imparting gas barrier properties such as water vapor and oxygen gas and weather resistance to the sheet.
  • Patent Document 1 discloses an electrically insulating polyethylene terephthalate (PET) film having a predetermined volume resistivity, a water vapor-blocking metallic film such as a metal oxide-deposited polyethylene terephthalate (PET) film or aluminum foil, and light.
  • PET polyethylene terephthalate
  • a back surface protection sheet for a solar cell in which a blocking polyethylene terephthalate (PET) film and a polyethylene naphthalate (PEN) film are bonded with a polyurethane-based adhesive is disclosed.
  • Patent Document 2 discloses a back surface protection sheet for solar cells in which a gas barrier vapor deposition film in which a vapor deposition layer made of an inorganic oxide is provided on a base film and a polyester film having electrical insulation properties are laminated. Has been.
  • the aluminum foil may be deformed due to the shearing stress at the time of punching and aluminum may protrude from the side surface of the hole. .
  • the aluminum protruding to the hole side may come into contact with the electrode of the solar battery cell, and the performance of the solar battery element may be deteriorated.
  • the thickness of the aluminum foil is increased, the flexibility of the protective sheet itself is lowered and workability is deteriorated.
  • a coating layer made of a composite composed of a water-soluble polymer such as polyvinyl alcohol (PVA) and at least one metal alkoxide and / or a hydrolyzate thereof is deposited with an inorganic oxide.
  • PVA polyvinyl alcohol
  • a polymer such as PVA does not have a sufficient water vapor gas barrier property and the main chain CC bond is easily broken by ultraviolet rays, so deterioration is inevitable. Without this combination configuration, problems arise in the long-term reliability of the gas barrier property and weather resistance of the single unit.
  • a back surface protection sheet in order to form an oxide vapor deposition film on the surface of the base film, a large-scale vacuum system is required. Further, after the oxide vapor deposition film is formed, a water-soluble polymer and a metal alkoxide and Since a process of coating a composite comprising the hydrolyzate is necessary, the number of manufacturing processes increases. As a result, such a sheet has a problem that the manufacturing cost increases.
  • a resin film having weather resistance such as a fluorine-based resin or an olefin-based resin
  • base film bonded to one or both surfaces of the above-described gas barrier layer (base film).
  • Etc. are pasted together.
  • the C—C bond that is the main chain of the resin component is easily cut by ultraviolet rays, the deterioration of the resin film is unavoidable, and the gas barrier property is also deteriorated along with the deterioration of the weather-resistant resin film by ultraviolet rays. To do.
  • the present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a back surface protection sheet for a solar cell that can simultaneously satisfy weather resistance, gas barrier properties, and flexibility.
  • the present invention provides a back surface protection sheet for solar cells that employs the following configuration.
  • a base film composed of at least one layer, an aluminum foil disposed on one side or both sides of the base film, and a surface of the aluminum foil opposite to the surface on which the base film is disposed
  • a back protective sheet for solar cells comprising at least one coat layer comprising at least one layer,
  • the coating layer includes a metal alkoxide having a reactive functional group (Y), an acrylic monomer having a reactive functional group (X) that reacts with the reactive functional group (Y), and a reactive functional group
  • a back protective sheet for a solar cell which is a ternary copolymer layer obtained by curing a liquid coating film having a resin component comprising an acrylic monomer having no X).
  • the metal alkoxide has a general formula: YM (OR) 3 , YRM (OR) 2 , YR 2 M (OR) (wherein M is a metal, R is an alkyl group, and Y is a functional group having reactivity)
  • YM (OR) 3 a general formula: YM (OR) 3 , YRM (OR) 2 , YR 2 M (OR) (wherein M is a metal, R is an alkyl group, and Y is a functional group having reactivity)
  • the solar cell back surface protective sheet according to the present invention has a laminated structure in which an aluminum foil is laminated on a base film, and a predetermined coat layer is formed so as to sandwich the aluminum together with the base film. It satisfies the weather resistance, gas barrier properties and flexibility at the same time, and has excellent practicality.
  • FIG. 1 is a cross-sectional configuration diagram illustrating an example of a solar cell back surface protective sheet according to the present invention.
  • FIG. 2 is a cross-sectional configuration diagram showing Modification 1 of the back surface protection sheet for a solar cell according to the present invention.
  • FIG. 3 is a cross-sectional configuration diagram showing Modification Example 2 of the back surface protection sheet for a solar cell according to the present invention.
  • FIG. 4 is a schematic view for explaining the characteristics of the ternary copolymer constituting the coat layer of the back protective sheet for solar cells according to the present invention.
  • FIG. 5 is a schematic diagram for explaining the characteristics of the polymer constituting the composite coating layer of the conventional back protective sheet for solar cells.
  • FIG. 1 is a cross-sectional configuration diagram illustrating an example of a solar cell back surface protective sheet according to the present invention.
  • FIG. 2 is a cross-sectional configuration diagram showing Modification 1 of the back surface protection sheet for a solar cell according to the present invention.
  • FIG. 3 is a
  • FIG. 6 is a schematic diagram for explaining the self-healing characteristics of the ternary copolymer constituting the coat layer of the back protective sheet for solar cells according to the present invention.
  • FIG. 7 is a diagram showing an infrared total reflection absorption spectrum of a dry coating film of a commercially available emulsion main ingredient used as a liquid material used in the present invention.
  • FIG. 8 is a diagram showing an infrared total reflection absorption spectrum of the ternary copolymer layer prepared in Example 1.
  • the back surface protection sheet for solar cells includes a base film composed of at least one layer, an aluminum foil disposed on one side or both sides of the base film, and the base film of the aluminum foil.
  • a back protective sheet for a solar cell comprising at least one coat layer composed of at least one layer disposed on the side opposite to the surface, wherein the coat layer has a reactive functional group (Y).
  • a resin component comprising a metal alkoxide, an acrylic monomer having a reactive functional group (X) that reacts with the reactive functional group (Y), and an acrylic monomer having no reactive functional group (X) It is a ternary copolymer layer obtained by curing a liquid coating film having
  • Liquid having a resin component composed of an acrylic monomer not having a water content means an aqueous emulsion containing a resin component composed of only the above three monomers at a predetermined concentration (preferably a concentration of 50% by weight in the end). And a resin solution obtained by dissolving a resin component consisting of only the three monomers in a non-aqueous solvent.
  • the base film may have a single layer structure or a multilayer structure of two or more layers.
  • Aluminum foil as a gas barrier film such as water vapor or oxygen gas is disposed on one side or both sides of the base film having a multilayer structure of one layer or two or more layers.
  • One or two coat layers comprising at least one layer are formed so as to sandwich an aluminum foil together with the base film.
  • the formed coating layer includes a metal alkoxide having a reactive functional group (Y), an acrylic monomer having a reactive functional group (X) that reacts with the reactive functional group (Y), and a reactive functional group. It is a ternary copolymer layer obtained by polymerizing and curing a liquid coating film having a resin component composed of an acrylic monomer having no group (X).
  • the coating film may be formed in one layer or in multiple layers.
  • the said base film When making the said base film into a multilayer structure, it is preferable to interpose a silane adhesive layer between each base film. Moreover, it is preferable that at least 1 layer of the said base film which consists of at least 1 layer shall be a film with an inorganic oxide vapor deposition film. That is, when a base film consists of 1 layer, it is preferable that the 1 layer film is a film with an inorganic oxide vapor deposition film. And when making a base film into a multilayer structure, it is preferable to make at least 1 layer of them into a film with an inorganic oxide vapor deposition film
  • FIG. 1 is a cross-sectional structure showing an embodiment of the solar battery backsheet of the present invention.
  • FIG. 2 is a cross-sectional structure showing Modification 1 of the embodiment of the solar cell backsheet of the present invention.
  • FIG. 3 is a cross-sectional structure showing Modification 2 of the embodiment of the solar cell backsheet of the present invention.
  • the base film 1 has a single-layer structure, and a laminated structure in which an aluminum foil 2 is disposed on one side of the base film 1 and a coat layer 3 having a single-layer structure is formed so as to sandwich the aluminum foil 2. Shows the case.
  • the present invention may have a laminated structure as shown in FIGS. In FIG.
  • the aluminum foil 2 is arrange
  • the case of each laminated structure is shown.
  • the aluminum foil 2 is arrange
  • 3 shows a case of a laminated structure in which a coating layer 3 is formed on the side of the base film 1 on which the aluminum foil 2 is not disposed.
  • the base film 1 a resin film that can be molded and processed within a range that does not melt and soften while being appropriately adjusted within a predetermined heating time because it is heated in a hot press when forming a solar cell module is used. it can.
  • the material of the base film 1 include at least one selected from polyester resins, polyolefin resins, polystyrene resins, polyamide resins, polycarbonate resins, and polyacrylonitrile resins.
  • examples of the base film 1 include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin films such as polyethylene and polypropylene, polystyrene films, polyamide films, and polycarbonate. Engineering plastic films such as films, polyacrylonitrile films, and polyimide films are used.
  • the thickness of the base film 1 is in the range of 3 to 300 ⁇ m.
  • the surface of the film is oxidized by irradiation treatment or flame treatment using oxygen plasma or corona discharge.
  • oxidizing the surface many functional groups are present on the surface.
  • a film rich in surface functional groups tends to have better adhesion with a silane-based adhesive. Therefore, it is preferable to use a film that has been appropriately surface-treated as the base film 1.
  • the film used as this 1 layer structure base film 1 may vapor-deposit the inorganic oxide on the surface.
  • the base film 1 when the base film 1 has a multilayer structure, at least one of them is a film with an inorganic oxide vapor deposition film, and the number of layers of the film with a vapor deposition film according to the required degree of gas barrier properties. Can be incorporated.
  • bonding a film with a vapor deposition film it is preferable to bond a vapor deposition surface to the PET surface which does not have a vapor deposition film.
  • the inorganic oxide for vapor deposition silicon oxide, aluminum oxide, zinc oxide, or the like can be used, and the vapor deposition thickness is preferably 1 nm to 100 nm.
  • urethane, acrylic, epoxy, and silicon adhesives have been used in the past. Deterioration was a problem.
  • silane-based adhesive having excellent adhesive performance even at high temperature and high humidity is used for bonding the films constituting the base film 1 having a multilayer structure.
  • the silane-based adhesive referred to here is a conventional silane coupling agent or an alkoxy which is one of the metal alkoxide compounds contained in the resin component (ternary monomer) used for forming the coating layer in the present invention. Mixtures containing silane can be used.
  • the alkoxy group of alkoxysilane is hydrolyzed to produce a silanol group (Si—OH), and this silanol group is oxidized by oxygen plasma or corona discharge on the film surface. Since it reacts and binds, the adhesiveness between films is good. Further, since hydrolysis does not occur even under high temperature and high humidity, it has excellent weather resistance because of good adhesive properties and a strong silanol bond against UV energy.
  • the combination structure includes the same types of films, different types of films, In addition, a combination of the same films with an inorganic oxide deposited on one side or a combination of different films with an inorganic oxide deposited on one side may be used.
  • the aluminum foil 2 has a predetermined thickness that can exhibit sufficient gas barrier properties together with a coat layer 3 to be described later.
  • the thickness of the aluminum foil 2 is adjusted depending on the thickness of the coat layer 3, but is usually in the range of 9 to 30 ⁇ m.
  • the aluminum foil 2 is bonded to the base film 1 using a urethane adhesive, and the aluminum foil 2 is laminated on the base film 1.
  • a coating layer 3 is formed in a thickness range of 5 to 300 ⁇ m on at least the surface of the base film 1 on which the aluminum foil 2 is laminated (one side in FIG. 1).
  • the coating layer 3 has reactive functional groups (
  • the liquid means a metal alkoxide having a reactive functional group (Y), an acrylic monomer having a reactive functional group (X) that reacts with the reactive functional group (Y), and a reactive monomer.
  • aqueous emulsion containing a resin component consisting of only three types of monomers with an acrylic monomer having no functional group (X) at a predetermined concentration (preferably a final concentration of 50% by weight), or the above three types
  • a resin component consisting of only three types of monomers with an acrylic monomer having no functional group (X) at a predetermined concentration (preferably a final concentration of 50% by weight), or the above three types
  • the metal alkoxide having a reactive functional group is a general formula: YM (OR) 3 , YRM (OR) 2 , YR 2 M (OR) (wherein M is a metal, R is an alkyl group, Y Represents a functional group having reactivity).
  • Examples of the metal alkoxide having such a reactive functional group (Y) include ⁇ , ⁇ -ethylenically unsaturated monomers containing silane, such as vinyltrimethoxysilane, vinyltriisopropoxysilane, allyltrimethoxysilane, diallyldimethyl.
  • tetraalkoxysilane In addition to the metal alkoxide having the reactive functional group (Y), tetraalkoxysilane, trialkoxyaluminum, tetraalkoxytitanium and the like may be added.
  • the reactive functional group (Y) of the metal alkoxide has an isocyanate group, it is reactive for the purpose of suppressing the direct reaction with water and effectively promoting the reaction with the reactive functional group (X).
  • a capping agent also called a blocking agent or a protective agent
  • Any suitable aliphatic, alicyclic, or aromatic alkyl monoalcohol or phenolic compound can be used as the capping agent.
  • Examples of the aliphatic, alicyclic, or aromatic alkyl monoalcohol include lower aliphatic groups such as methanol, ethanol, and n-butanol, 2-methyl-2-propanol, and 2-methyl-1-propanol. Mention may be made of alcohols; alicyclic alcohols such as cyclohexanol; aromatic alkyl alcohols such as phenyl carbinol and methyl phenyl carbinol.
  • the phenolic compound includes phenolic compounds such as phenol itself and substituted phenols such as cresol and nitrophenol (the substituent does not affect the coating operation).
  • glycol ether can also be used as a capping agent.
  • Suitable glycol ethers include ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol methyl ether and propylene glycol methyl ether. Of the glycol ethers, diethylene glycol butyl ether is preferred.
  • capping agents include oximes such as methyl ethyl ketoxime, acetone oxime and cyclohexanone oxime, lactams such as ⁇ -caprolactam, and amines such as dibutylamine.
  • the capping agent modified with an isocyanate group is coated in the emulsion and then volatilized (azeotropically) with moisture by heat drying or decomposed by heating, whereby a reactive functional group (isocyanate)
  • the polymerization starts.
  • the desorption reaction of the capping agent is caused by heating to 80 ° C. or higher. However, when the temperature exceeds 120 ° C., the polymerization of the monomer proceeds rapidly. Therefore, the heating for desorption of the capping agent is performed at 80 ° C. It is preferable to carry out at a temperature in the range of ⁇ 120 ° C. This capping agent desorption reaction is usually realized simultaneously in the coating film drying step.
  • the reactive functional group (X) has a property of reacting with and binding to the reactive functional group (Y) of the metal alkoxide such as an ester group, an epoxy group, a ketone group, an amino group, and a hydroxyl group. It is a functional group having.
  • acrylic monomers having such a reactive functional group (X) include ⁇ , ⁇ -ethylenically unsaturated monomers such as hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and hydroxy (meth) acrylate.
  • ⁇ , ⁇ -ethylenic group having a hydroxyl group such as propyl, hydroxybutyl (meth) acrylate, methacryl alcohol, 4-hydroxybutyl acrylate glycidyl (epoxy) ether, adduct of hydroxyethyl (meth) acrylate and ⁇ -caprolactone And saturated monomers.
  • “having no reactive functional group (X)” means having no functional group that reacts with the metal alkoxide having the reactive functional group (Y).
  • the acrylic monomer having no reactive functional group (X) include ⁇ , ⁇ -ethylenically unsaturated monomers such as (meth) acrylate esters [for example, methyl (meth) acrylate, ethyl (meth) acrylate, (Meth) acrylic acid-n-propyl, (meth) acrylic acid isopropyl, (meth) acrylic acid-n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid-t-butyl, (meth) acrylic acid- 2-ethylhexyl, lauryl methacrylate, phenyl acrylate, isobornyl (meth) acrylate, cyclohexyl methacrylate, (meth) acrylate-t-butylcyclohexyl, (meth) acrylate di
  • a ternary copolymer layer obtained by polymerizing and curing a liquid coating film having the above three types of monomers as resin components may be obtained by simultaneously polymerizing the three types of monomers.
  • acrylic monomer having reactive functional group (X) and “acrylic monomer not having reactive functional group (X)”, are mixed or partially polymerized. It is preferable to employ a process in which the remaining “metal alkoxide having a reactive functional group (Y)” is mixed and polymerized after semi-polymerization.
  • the terpolymer is finally obtained by coating on a base film as a ternary copolymer layer.
  • the timing of mixing, coating and polymerization of each monomer is mixed ⁇ polymerization. (Semi-polymerization) ⁇ Coating (after additional mixing if there are remaining monomers) ⁇ Polymerization (drying), or Mixing ⁇ Coating ⁇ Polymerization (drying).
  • aqueous solvent ion exchange water or the like is used.
  • a conventional dispersant may be added to an aqueous medium containing an organic solvent such as alcohol to improve the dispersibility.
  • a conventional homogenizer for example, trade name “NR-300”, manufactured by Microtech Nichion Co., Ltd.
  • Polymerization can be carried out by previously dropping the monomer and the polymerization initiator in a combination of two kinds.
  • the concentration of the resin component is preferably 30 to 60% by weight.
  • the dispersion of the resin component constituting the emulsion from the desired particle size is reduced, and resin component particles having a preferable particle size range can be obtained.
  • polymerization initiator examples include azo oily compounds [for example, azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2- (2-imidazoline) -2-yl) propane) and 2,2′-azobis (2,4-dimethylvaleronitrile), etc.]; aqueous compounds [eg anionic 4,4′-azobis (4-cyanovaleric acid), 2, 2-azobis (N- (2-carboxyethyl) -2-methylpropionamidine) and cationic 2,2′-azobis (2-methylpropionamidine)]; redox oily peroxides (eg, benzoyl peroxide) Oxides, parachlorobenzoyl peroxide, lauroyl peroxide and t-butyl perbenzoate); and aqueous peroxides (eg If, like potassium persulfate and ammonium persulfate) and the like.
  • the blending ratio of the conventional dispersant and the resin component composed of the three types of monomers may be adjusted to a conventional ratio when preparing an emulsion.
  • the solid content may be adjusted to a range of 5/95 to 20/80.
  • the ratio is less than 5/95, the dispersed particles aggregate to form a lump and the smoothness of the coating film tends to be impaired.
  • the ratio exceeds 20/80, the film thickness tends to be difficult to control.
  • a mercaptan such as lauryl mercaptan and a chain transfer agent such as ⁇ -methylstyrene dimer may be used as necessary.
  • the polymerization reaction temperature of the mixed monomer is determined by the initiator. For example, it is preferably 60 to 90 ° C. when an azo initiator is used, and preferably 30 to 70 ° C. when a redox initiator is used.
  • the blending amount is generally 0.1 to 5% by mass, preferably 0.2 to 2% by mass, based on the total amount of the emulsion.
  • the monomer polymerization process includes two types of monomers, “an acrylic monomer having a reactive functional group (X)” and “an acrylic monomer having no reactive functional group (X)”. It is preferable to employ a process in which mixing or polymerization is partially advanced and semi-polymerization is performed, and then the remaining “metal alkoxide having a reactive functional group (Y)” is mixed and polymerized.
  • the polymerization in the case of reacting two kinds of monomers in advance is performed in 1 to 8 hours.
  • the average particle diameter of the obtained two-component semipolymer resin particles is preferably in the range of 0.05 to 0.30 ⁇ m. If the particle diameter is less than 0.05 ⁇ m, the effect of improving workability is small, and if it exceeds 0.30 ⁇ m, the appearance of the resulting coating film may be deteriorated.
  • the particle diameter can be adjusted, for example, by adjusting the composition of the two monomer mixtures and the emulsion polymerization conditions.
  • the mass average molecular weight of the two-component semipolymer resin particles is preferably 6000 to 12000. If it is less than 6000, the control of the film thickness tends to be difficult, and if it exceeds 12,000, the smoothness of the coating film tends to be lowered.
  • the resin solid content is preferably 3 to 20% by mass.
  • the resin solid content is less than 3% by mass, control of the film thickness tends to be difficult, and when it exceeds 20% by mass, the smoothness of the coating film tends to decrease.
  • non-aqueous solvent an organic solvent such as toluene or ethyl acetate is used.
  • non-aqueous solvent xylene, N-methylpyrrolidone, butyl acetate, aliphatic and / or aromatics having a relatively high boiling point, butyl diglycol acetate, acetone, and the like can be used as appropriate.
  • an initiator (azo-based or peroxide-based) that generates radicals by heat is used.
  • the above-described three kinds or two kinds of combinations of monomers and a polymerization initiator are dissolved to obtain a resin solution for polymerization or partial polymerization (semi-polymerization).
  • concentration of the resin component in the resin solution is preferably 30 to 60% by weight, more preferably 50% by weight.
  • the liquid material may be mixed with a resin component and a solvent and, if necessary, an ultraviolet scattering agent and / or an ultraviolet absorber.
  • the ultraviolet scattering agent include fine powders such as zinc oxide and titanium oxide.
  • the ultraviolet absorber include a dye having an ultraviolet absorbing ability and an acrylic polymer into which a high concentration benzotriazole group is introduced. By adding a small amount of such an ultraviolet scattering agent and / or an ultraviolet absorber, the weather resistance of the coating layer can be further improved.
  • the coating layer has a multilayer structure, it is preferable to mix the ultraviolet scattering agent and / or ultraviolet absorber in at least one layer, and the ultraviolet scattering agent and / or ultraviolet absorber is mixed in two or more layers or all layers. May be mixed.
  • liquid material products having an emulsion composition are commercially available, and it is also possible to use them.
  • examples of commercially available products include “Cirrus (trade name)” manufactured by Toagosei Co., Ltd. and “Sherastar MK (trade name)” manufactured by Nippon Paint Co., Ltd.
  • the film thickness after drying is on the opposite side of the surface of the aluminum foil 2 where the base film 1 is disposed.
  • the liquid coating film is formed so as to have a thickness of 6 to 350 ⁇ m.
  • a coating method of the liquid material conventionally known means such as a dipping method, a roll coating method, a screen printing method, a spray method and the like that are generally used can be used.
  • a plurality of thin coating layers may be laminated to have a predetermined film thickness. In the case of multiple layers, it is repeated that after the previously applied layer is dried, the next layer is applied, the layer is dried, and then the next layer is applied.
  • Step of forming a coat layer comprising a terpolymer layer This process includes a coating film drying process for drying the coating film, and a dry coating film curing process for finally forming a cured film (ternary copolymer layer) composed of a ternary copolymer after drying. ,included.
  • the solvent is vaporized from the liquid coating film to stabilize the shape of the coating film.
  • the drying temperature is preferably 80 ° C to 120 ° C. If it is less than 80 degreeC, vaporization of a solvent will become inadequate, and if it exceeds 100 degreeC, the polymerization reaction of the unreacted monomer in a coating film will be started.
  • the drying time depends on the drying temperature, it is preferably 10 to 15 minutes at 100 ° C., for example.
  • the coating film whose shape has been stabilized by drying is cured by polymerizing the unreacted monomer in the coating film.
  • the polymerization temperature of the unreacted monomer is preferably 80 ° C to 120 ° C. When the temperature is lower than 80 ° C., the polymerization becomes insufficient, and when the temperature exceeds 120 ° C., when the film is formed on the PET, the PET starts to shrink, and the coating film also adversely affects the adhesion and the like.
  • the polymerization time depends on the polymerization temperature, it is preferably 10 to 15 minutes at 100 ° C., for example.
  • the coating layer 3 comprising the terpolymer layer has gas barrier properties and weather resistance while maintaining flexibility, the obtained sheet has excellent long-term reliability as a back surface protection sheet for solar cells. It becomes.
  • PVA polyvinyl alcohol
  • Patent Document 2 polyvinyl alcohol
  • PVA has a water vapor permeability of 1100 g / m 2 ⁇ 24 hr (measurement conditions: 25 ° C., 90% RH, thickness of 25 ⁇ m), and has a poor water vapor barrier property but excellent flexibility.
  • the conventional back surface protection sheet for solar cells cracks when bent only with an inorganic oxide vapor deposition film as a gas barrier layer cannot be prevented. Therefore, by laminating a flexible polymer film such as PVA, Gas barrier properties are secured while maintaining flexibility. Therefore, the gas barrier property was insufficient without an inorganic oxide vapor deposition film. That is, the number of stacked layers is increased, making it difficult to control the total thickness of the sheets.
  • the coating layer 3 is made of acrylic as a monomer that can be copolymerized with a metal alkoxide.
  • PMMA polymethyl methacrylate
  • the property is excellent.
  • the measured values of water vapor permeability of the above polyvinyl alcohol and polymethyl methacrylate were ““ Animal testing methods and evaluation results for plastic materials ⁇ 5> ”, Takeo Yasuda, p.119, vol.51, No. .6, Plastics ”.
  • the monomer material of the ternary copolymer layer constituting the coat layer 3 is an acrylic monomer having a reactive functional group (X), an acrylic monomer having no reactive functional group (X), And a metal alkoxide having a reactive functional group (Y) that reacts with the reactive functional group (X). Then, a liquid material having these three types of monomers as resin components is formed, and the ternary copolymer layer obtained by forming the liquid material into a film is used as the coating layer 3.
  • ternary copolymer layer constituting the coat layer 3 As shown in FIG. 4, two kinds of acrylic monomers are combined in a chain by radical polymerization reaction, and the formed acrylic polymer chain Flexibility is maintained.
  • chain acrylic polymer a plurality of functional groups (X) derived from an acrylic monomer having one reactive functional group (X) are scattered at intervals.
  • (X) and the functional group (Y) in the metal alkoxide react and bond.
  • an MO bond is formed by hydrolysis of metal alkoxides having a reactive functional group (Y), and the terpolymer acquires a network structure. With this network structure, flexibility and high water vapor gas barrier properties and weather resistance can be realized. Therefore, even if the sheet of the present invention is bent, cracks do not occur and the gas barrier property does not deteriorate significantly.
  • the conventional product is used as a resin film having weather resistance by adhering a fluorine-based resin or the like on the gas barrier layer described above.
  • the C—F bond energy is 116 kcal, which is very strong against the ultraviolet energy of 96 kcal, but the C—C bond energy of the main chain is 85 kcal and weak against ultraviolet rays. Therefore, deterioration of the resin due to ultraviolet rays occurs.
  • the composite of the metal alkoxide and polymer in the gas barrier layer is a composite with a simple polymer that is not accompanied by a chemical bond with the hydrolysis product of the metal alkoxide.
  • the C—C bond (85 kcal) of the acrylic polymer portion is broken by ultraviolet rays.
  • the MO bond (106 to 145 kcal) due to the metal alkoxide is not broken. Even if the hydrolysis of the metal alkoxide progresses due to moisture in the air or in the polymer, and the C—C bond of the acrylic polymer is broken by the ultraviolet ray, self-healing can be performed by increasing the MO bond. There is almost no deterioration by.
  • the ternary copolymer layer adheres to a resin such as PET with a chemical bond, the adhesive property is very excellent, and the base film 1 and the ternary copolymer layer (coat layer 3). There is no worry of peeling between them.
  • the metal alcoside is hydrolyzed by moisture to form a MO bond in a network, and the —CH 2 —CHR— of the acrylic polymer is generally hardly hydrolyzed. Therefore, the conventional sheet with a structure in which a weather-resistant film and a base film with gas barrier properties are bonded with an adhesive as in the past, that is, moisture has entered from the outside due to deterioration of the resin film during long-term use.
  • the problem that the adhesive deteriorates due to hydrolysis and the films peel off does not occur in the sheet of the present invention.
  • the sheet according to the present invention can be provided as a back surface protection sheet for solar cells excellent in flexibility, super weather resistance, and water vapor gas barrier properties.
  • the commercially available product is a mixture of the acrylic monomer having the reactive functional group (X) and the acrylic monomer not having the reactive functional group (X)
  • dry coating of the product is performed. This can be confirmed by the infrared total reflection absorption spectrum of the film surface. This infrared total reflection absorption spectrum is shown in FIG.
  • Example 1 in Example 1 of the present invention, as an acrylic resin component A, an aqueous emulsion A in which 3-glycidoxypropyltriethoxysilane (1 part by weight) is blended with 15 parts by weight of the main component of Shellaster MK: A liquid body was prepared by blending 35 parts by weight of an aqueous emulsion B obtained by blending the ethylene resin component “AQUATECH 909” (45 wt%) as the ethylene resin component B with respect to 100 parts by weight.
  • an acrylic resin component A an aqueous emulsion A in which 3-glycidoxypropyltriethoxysilane (1 part by weight) is blended with 15 parts by weight of the main component of Shellaster MK: A liquid body was prepared by blending 35 parts by weight of an aqueous emulsion B obtained by blending the ethylene resin component “AQUATECH 909” (45 wt%) as the ethylene resin component B with respect to 100 parts by weight.
  • PET polyethylene terephthalate
  • Ester Film 5000 manufactured by Toyobo Co., Ltd.
  • a 5 ⁇ m-thick urethane adhesive (trade name “TMOFLEX-502” manufactured by Toyo Ink Co., Ltd.) was adhered to the base film, and an aluminum foil having a thickness of 9 ⁇ m was laminated on a polyethylene terephthalate (PET) film.
  • the liquid material is applied to the side of the base film on which the aluminum foil is laminated and opposite to the surface on which the base film of the aluminum foil is disposed, and the coating film is heated at 80 ° C. for 10 minutes.
  • the aqueous solvent was evaporated and dried.
  • the obtained dried coating film was heated at 100 ° C. for 10 minutes to polymerize unreacted monomers constituting the coating film, thereby obtaining a ternary copolymer layer (coat layer).
  • the thickness of the obtained film was 20 ⁇ m.
  • the infrared total reflection absorption spectrum of the copolymer layer is shown in FIG. As shown in FIG. 8, acrylic wave numbers 3690 to 3200 (cm ⁇ 1 ), 1760 to 1715 (cm ⁇ 1 ), 1150 to 1025 (cm ⁇ 1 ), 1100 to 1000 (cm ⁇ 1 ) A typical peak appears in the polymer.
  • 2845 to 2865 (cm ⁇ 1 ) and 2940 to 2915 (cm ⁇ 1 ) include methylene (—CH 2 —), 1650 to 1725 (cm ⁇ 1 ) C ⁇ O and 1280 ( Typical peaks appear in the unreacted residual carboxylic acid (—COOH) consisting of C—O of cm ⁇ 1 ) to 1320 and 2500 to 3600 (cm ⁇ 1 ).
  • the acrylic copolymer forms a sea phase and the ethylene copolymer forms an island phase.
  • 3690 to 3200 is a unit part containing a carboxylic acid (COOH group) or a hydroxyl group (OH) of an acrylic monomer having a reactive functional group (X) and a silanol group (Si -OH) or absorption derived from OH in the unit part containing a hydroxyl group (OH) generated by a ring-opening reaction of an epoxy group.
  • 1760 to 1715 is an absorption derived from C ⁇ O of a unit part containing an ester (COOR) of an acrylic monomer having no reactive functional group (X).
  • 1150 to 1025 is an absorption derived from C—O—C of the unit part containing an ester (COOR) or an ether (COC) of an acrylic monomer having no reactive functional group (X). is there.
  • 1100 to 1000 is an absorption derived from Si—O—Si of a unit part including a siloxane bond (Si—O) generated by a dehydration condensation reaction between silanol groups of an alkoxysilane monomer.
  • 2845 to 2265 (cm ⁇ 1 ) and 2940 to 2915 (cm ⁇ 1 ) are absorptions derived from methylene (—CH 2 —) constituting the ethylene-based resin component B, and are 1650 to 1725 (cm ⁇ 1).
  • C O and 1280 (cm ⁇ 1 ) to 1320
  • C—O and 2500 to 3600 (cm ⁇ 1 ) constitute the ethylene-based resin component B, and the remaining unreacted residual carboxylic acid (—COOH) Absorption derived from.
  • Example 2 of the present invention As shown in the following (Table 2), a polyethylene terephthalate (PET) film having a thickness of 188 ⁇ m (trade name “Ester Film 5000” manufactured by Toyobo Co., Ltd.) as a base film was used. An aluminum foil having a thickness of 30 ⁇ m was adhered to the base film with a urethane adhesive having a thickness of 5 ⁇ m (trade name “TMOFLEX-502” manufactured by Toyo Ink Co., Ltd.), and the aluminum foil having a thickness of 30 ⁇ m was adhered to polyethylene terephthalate (PET). ) Laminated on film.
  • PET polyethylene terephthalate
  • the liquid material is applied to the side of the base film on which the aluminum foil is laminated and opposite to the surface on which the base film of the aluminum foil is disposed, and the coating film is heated at 80 ° C. for 10 minutes. Then, the aqueous solvent was evaporated and dried. The obtained dried coating film was heated at 100 ° C. for 10 minutes to polymerize unreacted monomers constituting the coating film, thereby obtaining a ternary copolymer layer (coat layer). The thickness of the obtained film was 20 ⁇ m.
  • the infrared total reflection absorption spectrum of the ternary copolymer layer was the same as the spectrum shown in FIG.
  • Comparative Example 1 Moreover, as shown in the following (Table 2) as Comparative Example 1, a polyethylene terephthalate (PET) film (trade name “Ester Film 5000” manufactured by Toyobo Co., Ltd.) having a thickness of 188 ⁇ m was used as a base film. A 40 ⁇ m thick aluminum foil was adhered to the substrate film with a 5 ⁇ m thick urethane adhesive (trade name “TMOFLEX-502” manufactured by Toyo Ink Co., Ltd.), and the 40 ⁇ m thick aluminum foil was made of polyethylene terephthalate (PET).
  • PET polyethylene terephthalate
  • a back protective sheet (thickness from the outermost layer to the aluminum foil is 70 ⁇ m) laminated on the film and further laminated on the aluminum foil with a 25 ⁇ m thick fluorine-based PVF film with the 5 ⁇ m thick urethane adhesive.
  • the water vapor transmission amount was measured by the cup method under the conditions of a temperature of 40 ° C. and a humidity of 90% RH based on JIS Z0208.
  • the tensile strength was measured using a universal testing machine (trade name “UH-500 kNI”) manufactured by Shimadzu Corporation based on JIS K7127.
  • the initial water vapor gas barrier properties of the sheets of Examples 1 and 2 are equivalent to those of the sheet of Comparative Example 1 using an aluminum foil having a thickness of 40 ⁇ m.
  • seat of Example 1 and 2 is very excellent compared with the sheet
  • the punching workability of Examples 1 and 2 also prevents the aluminum ion from protruding into the side surface of the hole, and can avoid the poor performance of the solar ionization module caused by the burr of the aluminum foil that has occurred in the conventional product.
  • seat of Example 1 and 2 since the thickness of aluminum foil can be made thin, the expansion

Abstract

This solar-cell back-side protective sheet comprises: a base film (1) comprising at least one layer; a sheet or sheets of aluminum foil (2) disposed on one or both surfaces of the base film (1); and at least one coating layer (3), comprising at least one layer, disposed on the aluminum foil (2) surface(s) opposite the base film (1). This solar-cell back-side protective sheet is characterized in that each coating layer (3) is a ternary-copolymer layer obtained by curing a liquid film that has a resin component comprising: a metal alkoxide that has a reactive functional group (Y); an acrylic monomer that has a reactive functional group (X) that reacts with the aforementioned reactive functional group (Y); and an acrylic monomer that does not have said reactive functional group (X). The present invention makes it possible to provide a solar-cell-module base material that simultaneously exhibits gas-barrier functionality, weather resistance, and flexibility.

Description

太陽電池用裏面保護シートBack protection sheet for solar cells
　本発明は、優れた耐侯性を有するとともに、優れた耐水蒸気バリア性を備え、太陽電池パネルを製造する時の熱プレス成型や真空圧空成型の組み付け成型時に伴う多少の熱歪みや屈曲があっても水蒸気ガスバリア性が損なわれることのない柔軟性を有する太陽電池用裏面保護シートに関する。 The present invention has an excellent weather resistance and an excellent water vapor barrier resistance, and there is some thermal distortion and bending associated with the assembly of hot press molding and vacuum / pressure molding when manufacturing solar cell panels. The present invention also relates to a solar cell back surface protective sheet having flexibility that does not impair the water vapor gas barrier property.
　従来、太陽電池モジュールを構成する裏面保護シートとして、いくつかの構成が提案されている。これらのシートは、シートに水蒸気、酸素ガス等のガスバリア性や耐侯性を付与する工夫として、特性の異なるフィルムをそれぞれ接着剤で貼り合せ多層化したものが主流に用いられている。 Conventionally, several configurations have been proposed as back surface protection sheets constituting solar cell modules. As these sheets, a sheet in which films having different characteristics are laminated with an adhesive and multilayered is mainly used as a device for imparting gas barrier properties such as water vapor and oxygen gas and weather resistance to the sheet.
　例えば、特許文献１には、所定の体積抵抗率を有する電気絶縁性ポリエチレンテレフタレート（ＰＥＴ）フィルムと、金属酸化物蒸着ポリエチレンテレフタレート（ＰＥＴ）フィルム又はアルミニウム箔等の水蒸気遮断性金属質フィルムと、光遮断性のポリエチレンテレフタレート（ＰＥＴ）フィルムと、ポリエチレンナフタレート（ＰＥＮ）フィルムとを、ポリウレタン系接着剤で接着した太陽電池用の裏面保護シートが開示されている。 For example, Patent Document 1 discloses an electrically insulating polyethylene terephthalate (PET) film having a predetermined volume resistivity, a water vapor-blocking metallic film such as a metal oxide-deposited polyethylene terephthalate (PET) film or aluminum foil, and light. A back surface protection sheet for a solar cell in which a blocking polyethylene terephthalate (PET) film and a polyethylene naphthalate (PEN) film are bonded with a polyurethane-based adhesive is disclosed.
　また、特許文献２には、基材フィルム上に無機酸化物からなる蒸着層を設けたガスバリア性蒸着フィルムと、電気絶縁性等を有するポリエステルフィルムとを積層した太陽電池用の裏面保護シートが開示されている。 Patent Document 2 discloses a back surface protection sheet for solar cells in which a gas barrier vapor deposition film in which a vapor deposition layer made of an inorganic oxide is provided on a base film and a polyester film having electrical insulation properties are laminated. Has been.
特開２００９－２２４７６１号公報JP 2009-224761 A 特開２００６－２５３２６４号公報JP 2006-253264 A
　上記特許文献１に開示のようにアルミニウム箔をガスバリアフィルムとして用いる場合、実用上十分なガスバリア性を得るためには、シートのガスバリア性の確保をアルミニウム箔のみに依存する場合、３０μｍ以上の厚みを有するアルミニウム箔を使用する必要がある。しかしながら、アルミニウムと、アルミニウム箔に隣接する樹脂層を構成する樹脂とでは、熱膨張率に大きな差があるので、アルミニウム箔の厚みが３０μｍを超えると、太陽電池モジュールを製造する時にシートに加えられる１５０℃程度の熱プレスの熱により、アルミニウム箔に隣接する樹脂フィルム層とアルミニウム箔との熱膨張量の差が顕著になる。そのため、熱シール後の裏面保護シートに変形が生じる場合がある。 When an aluminum foil is used as a gas barrier film as disclosed in Patent Document 1, in order to obtain a practically sufficient gas barrier property, the thickness of 30 μm or more is required when the gas barrier property of the sheet depends only on the aluminum foil. It is necessary to use the aluminum foil which has. However, since there is a large difference in coefficient of thermal expansion between aluminum and the resin constituting the resin layer adjacent to the aluminum foil, when the thickness of the aluminum foil exceeds 30 μm, it is added to the sheet when manufacturing the solar cell module. The difference in thermal expansion between the resin film layer adjacent to the aluminum foil and the aluminum foil becomes noticeable due to the heat of the hot press at about 150 ° C. Therefore, the back surface protection sheet after heat sealing may be deformed.
　また、裏面保護シートの封止加工時に打ち抜き穴を形成するが、アルミニウム箔の厚みが３０μｍを超えると、打ち抜き時の剪断応力を受けてアルミニウム箔が変形して穴側面にアルミニウムがはみ出す場合がある。このような場合、穴側にはみ出したアルミニウムが太陽電池セルの電極に接触して、太陽電池素子の性能が不良となるおそれがある。
　さらに、アルミニウム箔の厚みが厚くなると、保護シート自体のフレキシブル性が低下し作業性が悪くなる。 Moreover, although a punching hole is formed during the sealing process of the back surface protection sheet, when the thickness of the aluminum foil exceeds 30 μm, the aluminum foil may be deformed due to the shearing stress at the time of punching and aluminum may protrude from the side surface of the hole. . In such a case, the aluminum protruding to the hole side may come into contact with the electrode of the solar battery cell, and the performance of the solar battery element may be deteriorated.
Furthermore, when the thickness of the aluminum foil is increased, the flexibility of the protective sheet itself is lowered and workability is deteriorated.
　一方、上記特許文献２に開示の裏面保護シートでは、ポリビニルアルコール（ＰＶＡ）など水溶性高分子と１種類以上の金属アルコキシド及び/又はその加水分解物からなる複合物によるコート層を無機酸化物蒸着膜の上に設けることで、ガスバリア性を確保している。しかし、かかる裏面保護シートでは、ＰＶＡなどの高分子は水蒸気ガスバリア性が十分ではないことと、紫外線により主鎖であるＣ－Ｃ結合が切れ易い為、劣化は避けられず、酸化物蒸着膜との組み合わせ構成なしには、単体でのガスバリア性及びその耐侯性の長期信頼性において問題が生じる。また、かかる裏面保護シートでは、基材フィルム表面に酸化物蒸着膜を形成するために、大掛かりな真空系の設備が必要になり、さらに、酸化物蒸着膜形成後に水溶性高分子と金属アルコキシド及び／又はその加水分解物からなる複合物のコーティングを行うという工程が必要になるために製造工程が多くなる。これらにより、係るシートでは、製造コストが高くなるという問題が生じる。 On the other hand, in the back surface protection sheet disclosed in Patent Document 2, a coating layer made of a composite composed of a water-soluble polymer such as polyvinyl alcohol (PVA) and at least one metal alkoxide and / or a hydrolyzate thereof is deposited with an inorganic oxide. By providing on the film, gas barrier properties are secured. However, in such a backside protective sheet, a polymer such as PVA does not have a sufficient water vapor gas barrier property and the main chain CC bond is easily broken by ultraviolet rays, so deterioration is inevitable. Without this combination configuration, problems arise in the long-term reliability of the gas barrier property and weather resistance of the single unit. In addition, in such a back surface protection sheet, in order to form an oxide vapor deposition film on the surface of the base film, a large-scale vacuum system is required. Further, after the oxide vapor deposition film is formed, a water-soluble polymer and a metal alkoxide and Since a process of coating a composite comprising the hydrolyzate is necessary, the number of manufacturing processes increases. As a result, such a sheet has a problem that the manufacturing cost increases.
　また、上記いずれのシートにおいても、耐侯性を付与するために、耐侯性を有する樹脂フィルム、例えばフッ素系樹脂又はオレフィン系樹脂などを上述のガスバリア層（基材フィルム）の片面又は両面へ接着剤などを用いて貼り合わせている。これらの樹脂フィルムは、いずれも紫外線により樹脂成分の主鎖となるＣ－Ｃ結合が切られ易いため、樹脂フィルムの劣化が避けられず、紫外線による耐侯性樹脂フィルムの劣化と共にそのガスバリア性も劣化する。そして、かかるガスバリア性の劣化に伴って、外部より裏面保護シート内部へ水蒸気が侵入して、基材フィルムと接着している接着層の接着剤が加水分解して劣化するため、基材フィルムと耐侯性樹脂フィルムの剥離等が発生するという問題がある。 In any of the above sheets, in order to impart weather resistance, a resin film having weather resistance, such as a fluorine-based resin or an olefin-based resin, is bonded to one or both surfaces of the above-described gas barrier layer (base film). Etc. are pasted together. In any of these resin films, since the C—C bond that is the main chain of the resin component is easily cut by ultraviolet rays, the deterioration of the resin film is unavoidable, and the gas barrier property is also deteriorated along with the deterioration of the weather-resistant resin film by ultraviolet rays. To do. As the gas barrier property deteriorates, water vapor enters the back surface protection sheet from the outside, and the adhesive of the adhesive layer adhered to the base film is hydrolyzed and deteriorated. There is a problem that peeling of the weather resistant resin film occurs.
　本発明は、上記従来技術の問題点に鑑みてなされたもので、その目的は、耐候性、ガスバリア性、柔軟性を同時に満足することのできる太陽電池用裏面保護シートを提供することにある。 The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a back surface protection sheet for a solar cell that can simultaneously satisfy weather resistance, gas barrier properties, and flexibility.
　上記課題を解決するために、本発明は、下記構成を採用した太陽電池用裏面保護シートを提供する。 In order to solve the above-described problems, the present invention provides a back surface protection sheet for solar cells that employs the following configuration.
[１]　少なくとも１層からなる基材フィルムと、該基材フィルムの片側又は両側に配置されるアルミニウム箔と、該アルミニウム箔の前記基材フィルムが配置された面とは反対面側に配置される少なくとも１層からなる１以上のコート層とを有してなる太陽電池用裏面保護シートであって、
　前記コート層が、反応性官能基（Ｙ）を有する金属アルコキシドと、前記反応性官能基（Ｙ）と反応する反応性の官能基（Ｘ）を有するアクリル系モノマーと、反応性の官能基（Ｘ）を有さないアクリル系モノマーとからなる樹脂成分を有する液状体の塗膜を硬化してなる３元共重合体層である太陽電池用裏面保護シート。
[２]　前記金属アルコキシドは、一般式：ＹＭ（ＯＲ）３、ＹＲＭ（ＯＲ）２、ＹＲ２Ｍ（ＯＲ）（式中、Ｍは金属、Ｒはアルキル基、Ｙは反応性を有する官能基を示す）で表される化合物であることを特徴とする上記[１]に記載の太陽電池用裏面保護シート。 [1] A base film composed of at least one layer, an aluminum foil disposed on one side or both sides of the base film, and a surface of the aluminum foil opposite to the surface on which the base film is disposed A back protective sheet for solar cells comprising at least one coat layer comprising at least one layer,
The coating layer includes a metal alkoxide having a reactive functional group (Y), an acrylic monomer having a reactive functional group (X) that reacts with the reactive functional group (Y), and a reactive functional group ( A back protective sheet for a solar cell, which is a ternary copolymer layer obtained by curing a liquid coating film having a resin component comprising an acrylic monomer having no X).
[2] The metal alkoxide has a general formula: YM (OR) 3 , YRM (OR) 2 , YR 2 M (OR) (wherein M is a metal, R is an alkyl group, and Y is a functional group having reactivity) The back surface protection sheet for solar cells according to [1] above, wherein
　本発明にかかる太陽電池用裏面保護シートは、基材フィルム上にアルミニウム箔を積層し、かつ該アルミニウムを前記基材フィルムとともに挟み込むように所定のコート層を形成積層構造を有しているので、耐侯性、ガスバリア性、柔軟性を同時に満足し、実用性に優れるものである。 The solar cell back surface protective sheet according to the present invention has a laminated structure in which an aluminum foil is laminated on a base film, and a predetermined coat layer is formed so as to sandwich the aluminum together with the base film. It satisfies the weather resistance, gas barrier properties and flexibility at the same time, and has excellent practicality.
図１は、本発明に係る太陽電池用裏面保護シートの一例を示す断面構成図である。FIG. 1 is a cross-sectional configuration diagram illustrating an example of a solar cell back surface protective sheet according to the present invention. 図２は、本発明に係る太陽電池用裏面保護シートの変形例１を示す断面構成図である。FIG. 2 is a cross-sectional configuration diagram showing Modification 1 of the back surface protection sheet for a solar cell according to the present invention. 図３は、本発明に係る太陽電池用裏面保護シートの変形例２を示す断面構成図である。FIG. 3 is a cross-sectional configuration diagram showing Modification Example 2 of the back surface protection sheet for a solar cell according to the present invention. 図４は、本発明に係る太陽電池用裏面保護シートのコート層を構成する３元共重合体の特性を説明するための模式図である。FIG. 4 is a schematic view for explaining the characteristics of the ternary copolymer constituting the coat layer of the back protective sheet for solar cells according to the present invention. 図５は、従来の太陽電池用裏面保護シートの複合系コート層を構成する重合体の特性を説明するための模式図である。FIG. 5 is a schematic diagram for explaining the characteristics of the polymer constituting the composite coating layer of the conventional back protective sheet for solar cells. 図６は、本発明に係る太陽電池用裏面保護シートのコート層を構成する３元共重合体の自己修復特性を説明するための模式図である。FIG. 6 is a schematic diagram for explaining the self-healing characteristics of the ternary copolymer constituting the coat layer of the back protective sheet for solar cells according to the present invention. 図７は、本発明で使用する液状体の材料として使用した市販品エマルション主剤の乾燥塗膜の赤外線全反射吸収スペクトルを示す図である。FIG. 7 is a diagram showing an infrared total reflection absorption spectrum of a dry coating film of a commercially available emulsion main ingredient used as a liquid material used in the present invention. 図８は、実施例１で作成した３元共重合体層の赤外線全反射吸収スペクトルを示す図である。FIG. 8 is a diagram showing an infrared total reflection absorption spectrum of the ternary copolymer layer prepared in Example 1.
　本発明に係る太陽電池用裏面保護シートは、少なくとも１層からなる基材フィルムと、該基材フィルムの片側又は両側に配置されるアルミニウム箔と、該アルミニウム箔の前記基材フィルムが配置された面とは反対面側に配置される少なくとも１層からなる１以上のコート層とを有してなる太陽電池用裏面保護シートであって、前記コート層が、反応性官能基（Ｙ）を有する金属アルコキシドと、前記反応性官能基（Ｙ）と反応する反応性の官能基（Ｘ）を有するアクリル系モノマーと、反応性の官能基（Ｘ）を有さないアクリル系モノマーとからなる樹脂成分を有する液状体の塗膜を硬化してなる３元共重合体層であることを特徴とする。 The back surface protection sheet for solar cells according to the present invention includes a base film composed of at least one layer, an aluminum foil disposed on one side or both sides of the base film, and the base film of the aluminum foil. A back protective sheet for a solar cell comprising at least one coat layer composed of at least one layer disposed on the side opposite to the surface, wherein the coat layer has a reactive functional group (Y). A resin component comprising a metal alkoxide, an acrylic monomer having a reactive functional group (X) that reacts with the reactive functional group (Y), and an acrylic monomer having no reactive functional group (X) It is a ternary copolymer layer obtained by curing a liquid coating film having
　上記の「反応性官能基（Ｙ）を有する金属アルコキシドと、前記反応性官能基（Ｙ）と反応する反応性の官能基（Ｘ）を有するアクリル系モノマーと、反応性の官能基（Ｘ）を有さないアクリル系モノマーとからなる樹脂成分を有する液状体」とは、前記３種のモノマーのみからなる樹脂成分を所定の濃度（好ましくは、最終的に濃度５０重量％）で含む水系エマルション、及び前記３種のモノマーのみからなる樹脂成分を非水系の溶媒に溶解した樹脂溶液を意味する。 The above-mentioned “metal alkoxide having a reactive functional group (Y), an acrylic monomer having a reactive functional group (X) that reacts with the reactive functional group (Y), and a reactive functional group (X)” "Liquid having a resin component composed of an acrylic monomer not having a water content" means an aqueous emulsion containing a resin component composed of only the above three monomers at a predetermined concentration (preferably a concentration of 50% by weight in the end). And a resin solution obtained by dissolving a resin component consisting of only the three monomers in a non-aqueous solvent.
　上記基材フィルムは、１層構成でもよく、２層以上の多層構成でもよい。かかる１層又は２層以上の多層構成の基材フィルムの片側又は両側には、水蒸気、酸素ガス等のガスバリアフィルムとしてのアルミニウム箔が配置される。前記基材フィルムとともにアルミニウム箔を挟みこむように、少なくとも１層からなるコート層が１または２形成される。形成されるコート層は、反応性官能基（Ｙ）を有する金属アルコキシドと、前記反応性官能基（Ｙ）と反応する反応性の官能基（Ｘ）を有するアクリル系モノマーと、反応性の官能基（Ｘ）を有さないアクリル系モノマーとからなる樹脂成分を有する液状体の塗膜を重合、硬化させた３元共重合体層である。前記塗膜は１層に形成してもよいし、多層に形成してもよい。 The base film may have a single layer structure or a multilayer structure of two or more layers. Aluminum foil as a gas barrier film such as water vapor or oxygen gas is disposed on one side or both sides of the base film having a multilayer structure of one layer or two or more layers. One or two coat layers comprising at least one layer are formed so as to sandwich an aluminum foil together with the base film. The formed coating layer includes a metal alkoxide having a reactive functional group (Y), an acrylic monomer having a reactive functional group (X) that reacts with the reactive functional group (Y), and a reactive functional group. It is a ternary copolymer layer obtained by polymerizing and curing a liquid coating film having a resin component composed of an acrylic monomer having no group (X). The coating film may be formed in one layer or in multiple layers.
　上記基材フィルムを多層構成とする場合は、各基材フィルム間にシラン系接着剤層を介装することが好ましい。
　また、上記少なくとも１層からなる基材フィルムの少なくとも１層は無機酸化物蒸着膜付きフィルムとすることが好ましい。すなわち、基材フィルムが１層からなる場合は、その１層のフィルムが無機酸化物蒸着膜付きフィルムであることが好ましい。そして、基材フィルムを多層構成とする場合は、その内の少なくとも１層を無機酸化物蒸着膜付きフィルムとすることが好ましく、その場合は各層間にシラン系接着剤を介装して各層を接着する。 When making the said base film into a multilayer structure, it is preferable to interpose a silane adhesive layer between each base film.
Moreover, it is preferable that at least 1 layer of the said base film which consists of at least 1 layer shall be a film with an inorganic oxide vapor deposition film. That is, when a base film consists of 1 layer, it is preferable that the 1 layer film is a film with an inorganic oxide vapor deposition film. And when making a base film into a multilayer structure, it is preferable to make at least 1 layer of them into a film with an inorganic oxide vapor deposition film | membrane, In that case, silane-type adhesives are interposed between each layer, and each layer is put. Glue.
　図１は、本発明の太陽電池バックシートの一実施形態を示す断面構造である。図２は、本発明の太陽電池バックシートの一実施形態の変形例１を示す断面構造である。図３は、本発明の太陽電池バックシートの一実施形態の変形例２を示す断面構造である。図１では、基材フィルム１は１層構成であり、この基材フィルム１の片側にアルミニウム箔２を配置し、このアルミニウム箔２を挟むように１層構成のコート層３を形成した積層構造の場合を示している。本発明は、図１の一実施の形態に加え、図２および図３に示すような積層構造を有する構成であってもよい。図２では、１層構成の基材フィルム１の両側にアルミニウム箔２を配置し、このアルミニウム箔２の基材フィルム１が配置された面とは反対面側に１層構成のコート層３をそれぞれ形成した積層構造の場合を示している。また、図３では、１層構成の基材フィルム１の片側にアルミニウム箔２を配置し、このアルミニウム箔２の基材フィルム１が配置された面とは反対面側に１層構成のコート層３を形成するとともに、基材フィルム１のアルミニウム箔２を配置しない側にもコート層３を形成した積層構造の場合を示している。
　以下、図面を参照しつつ、各構成要素について説明する。以下の図面では、代表として図１を参照して説明するが、図２及び図３の変形例においても、説明内容は同様である。 FIG. 1 is a cross-sectional structure showing an embodiment of the solar battery backsheet of the present invention. FIG. 2 is a cross-sectional structure showing Modification 1 of the embodiment of the solar cell backsheet of the present invention. FIG. 3 is a cross-sectional structure showing Modification 2 of the embodiment of the solar cell backsheet of the present invention. In FIG. 1, the base film 1 has a single-layer structure, and a laminated structure in which an aluminum foil 2 is disposed on one side of the base film 1 and a coat layer 3 having a single-layer structure is formed so as to sandwich the aluminum foil 2. Shows the case. In addition to the embodiment of FIG. 1, the present invention may have a laminated structure as shown in FIGS. In FIG. 2, the aluminum foil 2 is arrange | positioned on the both sides of the base film 1 of 1 layer structure, and the coating layer 3 of 1 layer structure is provided on the opposite side to the surface where the base film 1 of this aluminum foil 2 is arrange | positioned. The case of each laminated structure is shown. Moreover, in FIG. 3, the aluminum foil 2 is arrange | positioned at the one side of the base film 1 of 1 layer structure, and the coating layer of 1 layer structure is provided on the opposite side to the surface where the base film 1 of this aluminum foil 2 is arrange | positioned. 3 shows a case of a laminated structure in which a coating layer 3 is formed on the side of the base film 1 on which the aluminum foil 2 is not disposed.
Hereinafter, each component will be described with reference to the drawings. In the following drawings, description will be made with reference to FIG. 1 as a representative, but the description contents are the same in the modified examples of FIG. 2 and FIG.
（基材フィルムを用意する工程）
　基材フィルム１としては、太陽電池モジュールを形成する際の熱プレスにおいて、加温されるため所定の加熱時間内で適宜調整しながら溶融軟化しない範囲内で成形加工可能な樹脂フィルムを用いることができる。かかる基材フィルム１の材質としては、ポリエステル系樹脂、ポリオレフィン系樹脂、ポリスチレン系樹脂、ポリアミド樹脂、ポリカーボネート樹脂、及びポリアクリロニトリル樹脂から選ばれる少なくとも１種を挙げることができる。換言すれば、基材フィルム１の種類としては、例えば、ポリエチレンテレフタレート（ＰＥＴ)、ポリエチレンナフタレート（ＰＥＮ）などのポリエステル系フィルム、ポリエチレン、ポリプロピレン等のポリオレフィン系フィルム、ポリスチレン系フィルム、ポリアミドフィルム、ポリカーボネートフィルム、ポリアクリロニトリルフィルム、ポリイミドフィルム等のエンプラフィルムが用いられる。
　基材フィルム１の厚さは３～３００μｍの範囲とする。 (Process for preparing a base film)
As the base film 1, a resin film that can be molded and processed within a range that does not melt and soften while being appropriately adjusted within a predetermined heating time because it is heated in a hot press when forming a solar cell module is used. it can. Examples of the material of the base film 1 include at least one selected from polyester resins, polyolefin resins, polystyrene resins, polyamide resins, polycarbonate resins, and polyacrylonitrile resins. In other words, examples of the base film 1 include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin films such as polyethylene and polypropylene, polystyrene films, polyamide films, and polycarbonate. Engineering plastic films such as films, polyacrylonitrile films, and polyimide films are used.
The thickness of the base film 1 is in the range of 3 to 300 μm.
　上記フィルムは、その表面が酸素プラズマやコロナ放電による照射処理や火炎処理などで表面が酸化処理されているものが、好ましい。表面が酸化処理されることにより表面に多くの官能基が存在するようになる。表面の官能基が豊富なフィルムほど、シラン系接着剤との接着性が良好になる傾向がある。したがって、基材フィルム１には、適宜に表面処理を施したフィルムを用いることが好ましい。 It is preferable that the surface of the film is oxidized by irradiation treatment or flame treatment using oxygen plasma or corona discharge. By oxidizing the surface, many functional groups are present on the surface. A film rich in surface functional groups tends to have better adhesion with a silane-based adhesive. Therefore, it is preferable to use a film that has been appropriately surface-treated as the base film 1.
　また、上記基材フィルム１は１層構成である場合の例示であるが、この１層構成の基材フィルム１として用いるフィルムは無機酸化物をその表面に蒸着されたものであってもよい。本発明において、基材フィルム１を多層構成とする場合は、その内の少なくとも１層を無機酸化物蒸着膜付きフィルムとし、必要とされるガスバリア性の度合いに応じて蒸着膜付きフィルムの層数を組み込むことができる。また蒸着膜付きフィルムを貼り合わせる場合は、蒸着面を、蒸着膜の付いてないＰＥＴ面に貼り合わせることが好ましい。 Moreover, although the said base film 1 is the illustration in the case of 1 layer structure, the film used as this 1 layer structure base film 1 may vapor-deposit the inorganic oxide on the surface. In the present invention, when the base film 1 has a multilayer structure, at least one of them is a film with an inorganic oxide vapor deposition film, and the number of layers of the film with a vapor deposition film according to the required degree of gas barrier properties. Can be incorporated. Moreover, when bonding a film with a vapor deposition film, it is preferable to bond a vapor deposition surface to the PET surface which does not have a vapor deposition film.
　蒸着用の無機酸化物としては、酸化珪素や酸化アルミニウム、酸化亜鉛などを用いることができ、その蒸着厚さは１ｎｍ～１００ｎｍとすることが好ましい。 As the inorganic oxide for vapor deposition, silicon oxide, aluminum oxide, zinc oxide, or the like can be used, and the vapor deposition thickness is preferably 1 nm to 100 nm.
　フィルム同士を貼り合わせる際に用いる接着剤としては、従来からウレタン系、アクリル系、エポキシ系、シリコン系の各々の接着剤を用いられてきたが、高温高湿下において、加水分解による接着性能の劣化が問題となっていた。これに対して、本発明では、多層構成の基材フィルム１を構成するフィルム同士の接着には、高温高湿下でも接着性能の優れたシラン系接着剤を用いる。 As adhesives used to bond films together, urethane, acrylic, epoxy, and silicon adhesives have been used in the past. Deterioration was a problem. On the other hand, in the present invention, a silane-based adhesive having excellent adhesive performance even at high temperature and high humidity is used for bonding the films constituting the base film 1 having a multilayer structure.
　ここでいうシラン系の接着剤とは、慣用のシランカップリング剤や、本発明においてコート層を形成するために用いる樹脂成分（３元モノマー）に含まれる金属アルコキシド系化合物の１種であるアルコキシシランを含んだ混合物を用いることができる。 The silane-based adhesive referred to here is a conventional silane coupling agent or an alkoxy which is one of the metal alkoxide compounds contained in the resin component (ternary monomer) used for forming the coating layer in the present invention. Mixtures containing silane can be used.
　シラン系の接着剤は、アルコキシシランのアルコキシ基が加水分解してシラノール基（Ｓｉ－ＯＨ）が生成し、このシラノール基が、フィルム表面にある酸素プラズマやコロナ放電によって酸化されたカルボキシル基や水酸基と反応して結合するため、フィルム同士の接着性がよい。また高温高湿下においても加水分解が起こらないため、接着特性が良好であることと、シラノール結合がＵＶエネルギーに対して強いことから、優れた耐候性を有している。 In the silane-based adhesive, the alkoxy group of alkoxysilane is hydrolyzed to produce a silanol group (Si—OH), and this silanol group is oxidized by oxygen plasma or corona discharge on the film surface. Since it reacts and binds, the adhesiveness between films is good. Further, since hydrolysis does not occur even under high temperature and high humidity, it has excellent weather resistance because of good adhesive properties and a strong silanol bond against UV energy.
　基材フィルム１をシラン系の接着剤で貼り合わせた２層以上のフィルムから構成する場合、その組み合わせ構成としては、上記フィルムの中で、同じ種類のフィルム同士間、異なった種類のフィルム同士、また同じフィルム間同士でも一方に無機酸化物が蒸着されたもの、また異なるフィルム間でも一方に無機酸化物が蒸着されたもののいずれかの組合せでもよい。 When the base film 1 is composed of two or more layers bonded with a silane-based adhesive, the combination structure includes the same types of films, different types of films, In addition, a combination of the same films with an inorganic oxide deposited on one side or a combination of different films with an inorganic oxide deposited on one side may be used.
（アルミニウム箔を積層する工程）
　アルミニウム箔２は、後述するコート層３とともに十分なガスバリア性を発揮しうる所定の厚さのものを使用する。
　アルミニウム箔２の厚さは、コート層３の厚みに依存して調整されるが、通常９～３０μｍの範囲とする。 (Process of laminating aluminum foil)
The aluminum foil 2 has a predetermined thickness that can exhibit sufficient gas barrier properties together with a coat layer 3 to be described later.
The thickness of the aluminum foil 2 is adjusted depending on the thickness of the coat layer 3, but is usually in the range of 9 to 30 μm.
　上記基材フィルム１に、ウレタン系接着剤を使用してアルミニウム箔２を接着して、基材フィルム１にアルミニウム箔２を積層する。 The aluminum foil 2 is bonded to the base film 1 using a urethane adhesive, and the aluminum foil 2 is laminated on the base film 1.
（液状体を用意する工程）
　基材フィルム１の少なくともアルミニウム箔２が積層された面（図１では片側）に、厚さ５～３００μｍの範囲で、コート層３を形成するが、該コート層３は、反応性官能基（Ｙ）を有する金属アルコキシド、反応性官能基（Ｘ）を有するアクリル系モノマー、反応性の官能基（Ｘ）を有さないアクリル系モノマーからなる樹脂成分を有する液状体の塗膜を硬化させた３元共重合体層である。ここでいう液状体とは、反応性官能基（Ｙ）を有する金属アルコキシドと、前記反応性官能基（Ｙ）と反応する反応性の官能基（Ｘ）を有するアクリル系モノマーと、反応性の官能基（Ｘ）を有さないアクリル系モノマーとの３種のモノマーのみからなる樹脂成分を所定の濃度（好ましくは、最終的に濃度５０重量％）で含む水系エマルションであるか、前記３種のモノマーのみからなる樹脂成分を非水系の溶媒に溶解した樹脂溶液である。 (Process for preparing liquid material)
A coating layer 3 is formed in a thickness range of 5 to 300 μm on at least the surface of the base film 1 on which the aluminum foil 2 is laminated (one side in FIG. 1). The coating layer 3 has reactive functional groups ( A liquid coating film having a resin component composed of a metal alkoxide having Y), an acrylic monomer having a reactive functional group (X), and an acrylic monomer having no reactive functional group (X) was cured. It is a ternary copolymer layer. The liquid here means a metal alkoxide having a reactive functional group (Y), an acrylic monomer having a reactive functional group (X) that reacts with the reactive functional group (Y), and a reactive monomer. It is an aqueous emulsion containing a resin component consisting of only three types of monomers with an acrylic monomer having no functional group (X) at a predetermined concentration (preferably a final concentration of 50% by weight), or the above three types The resin solution which melt | dissolved the resin component which consists only of said monomer in the nonaqueous solvent.
　上記反応性官能基（Ｙ)を有する金属アルコキシドとは、一般式：ＹＭ（ＯＲ）３、ＹＲＭ（ＯＲ）２、ＹＲ２Ｍ（ＯＲ）(式中、Ｍは金属、Ｒはアルキル基、Ｙは反応性を有する官能基を示す)で表される化合物である。 The metal alkoxide having a reactive functional group (Y) is a general formula: YM (OR) 3 , YRM (OR) 2 , YR 2 M (OR) (wherein M is a metal, R is an alkyl group, Y Represents a functional group having reactivity).
　かかる反応性官能基（Ｙ）を有する金属アルコキシドとしては、特にシランを含んだα，β－エチレン性不飽和モノマー、例えば、ビニルトリメトキシシラン、ビニルトリイソプロポキシシラン、アリルトリメトキシシラン、ジアリルジメチルシラン、３－メタクリロキシプロピルトリメトキシシラン、３－メタクリロキシプロピルメチルジメトキシシラン、３－メタクリロキシプロピルトリエトキシシラン、３－メルカプトプロピルトリエトキシシラン、３－オクタノイルチオ－１－プロピルトリエトキシシラン、３－アミノプロピルトリエトキシシラン、３－アミノプロピルトリメトキシシラン、Ｎ－(２－アミノエチル)－３－アミノプロピルメチルジメトキシシラン、Ｎ－(２－アミノエチル)－３－アミノプロピルトリメトキシシラン、３－ウレイドプロピルトリエトシキシシラン、３－イソシアネートプロピルトリエトシキシラン、３－イソシアネートプロピルトリメトキシシランなどのα，β－エチレン性不飽和モノマーなどから選ばれる１種又は混合物を挙げることができる。 Examples of the metal alkoxide having such a reactive functional group (Y) include α, β-ethylenically unsaturated monomers containing silane, such as vinyltrimethoxysilane, vinyltriisopropoxysilane, allyltrimethoxysilane, diallyldimethyl. Silane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-octanoylthio-1-propyltriethoxysilane, 3- Aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane 3-ureidopropyl triethoxysilane Toshiki silane, 3-isocyanate propyl triethoxysilane Toshiki silane, 3-isocyanate propyl trimethoxysilane α such, mention may be made of one or a mixture selected from such β- ethylenically unsaturated monomers.
　なお、上記の反応性官能基（Ｙ）を有する金属アルコキシドに加えて、テトラアルコキシシラン、トリアルコキシアルミニウム、テトラアルコキシチタンなどを添加してもよい。 In addition to the metal alkoxide having the reactive functional group (Y), tetraalkoxysilane, trialkoxyaluminum, tetraalkoxytitanium and the like may be added.
　なお、上記金属アルコキシドの反応性官能基（Ｙ）にイソシアネート基を有する場合、水との直接反応を抑制し、反応性官能基（Ｘ）との反応を有効に進める事を目的に、反応性官能基（Ｙ）に対してキャッピング剤（ブロック剤、又は保護剤とも呼ばれている）を用いる。キャッピング剤としては、任意の適切な脂肪族、脂環式、又は芳香族のアルキルモノアルコール又はフェノール性化合物が使用され得る。 In addition, when the reactive functional group (Y) of the metal alkoxide has an isocyanate group, it is reactive for the purpose of suppressing the direct reaction with water and effectively promoting the reaction with the reactive functional group (X). A capping agent (also called a blocking agent or a protective agent) is used for the functional group (Y). Any suitable aliphatic, alicyclic, or aromatic alkyl monoalcohol or phenolic compound can be used as the capping agent.
　上記脂肪族、脂環式、又は芳香族のアルキルモノアルコールとしては、例えば、メタノール、エタノール、及びｎ－ブタノール、２―メチル―２―プロパノール、２―メチル―１―プロパノールのような低級脂肪族アルコール；シクロヘキサノールのような脂環式アルコール；フェニルカルビノール及びメチルフェニルカルビノールのような芳香族アルキルアルコールを挙げることができる。 Examples of the aliphatic, alicyclic, or aromatic alkyl monoalcohol include lower aliphatic groups such as methanol, ethanol, and n-butanol, 2-methyl-2-propanol, and 2-methyl-1-propanol. Mention may be made of alcohols; alicyclic alcohols such as cyclohexanol; aromatic alkyl alcohols such as phenyl carbinol and methyl phenyl carbinol.
　上記フェノール性化合物としては、フェノール自身及びクレゾール及びニトロフェノールのような置換フェノール（該置換基はコーティング操作に影響しない）のようなフェノール性化合物が包含される。 The phenolic compound includes phenolic compounds such as phenol itself and substituted phenols such as cresol and nitrophenol (the substituent does not affect the coating operation).
　キャッピング剤としては、その他に、グリコールエーテルも使用され得る。適切なグリコールエーテルとしては、エチレングリコールブチルエーテル、ジエチレングリコールブチルエーテル、エチレングリコールメチルエーテル及びプロピレングリコールメチルエーテルが挙げられる。グリコールエーテルの中でもジエチレングリコールブチルエーテルが好ましい。 In addition, glycol ether can also be used as a capping agent. Suitable glycol ethers include ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol methyl ether and propylene glycol methyl ether. Of the glycol ethers, diethylene glycol butyl ether is preferred.
　さらに、他のキャッピング剤としては、メチルエチルケトオキシム、アセトンオキシム及びシクロヘキサノンオキシムのようなオキシム、ε－カプロラクタムのようなラクタム、及びジブチルアミンのようなアミンが挙げられる。 Furthermore, other capping agents include oximes such as methyl ethyl ketoxime, acetone oxime and cyclohexanone oxime, lactams such as ε-caprolactam, and amines such as dibutylamine.
　適切なキャッピング剤を用いるに当たっては、塗膜の乾燥、反応温度に適したものを選択し用いることができる。 When using an appropriate capping agent, it is possible to select and use one suitable for drying the coating and reaction temperature.
　反応は、イソシアネート基に修飾したキャッピング剤が、エマルション中において、塗工された後、加熱乾燥で水分とともに揮発（共沸）されるか、加熱で分解されることで、反応性官能基（イソシアネート基）から外れ、それとともに重合が始まる。キャッピング剤の脱離反応は８０℃以上に加熱することにより生じるが、１２０℃を超えて加熱すると、モノマーの重合が急速に進行するので、キャッピング剤の脱離を目的とする加熱は、８０℃～１２０℃の範囲内の温度にて行うことが好ましい。このキャッピング剤の脱離反応は、通常塗膜の乾燥工程において同時に実現される。 In the reaction, the capping agent modified with an isocyanate group is coated in the emulsion and then volatilized (azeotropically) with moisture by heat drying or decomposed by heating, whereby a reactive functional group (isocyanate) The polymerization starts. The desorption reaction of the capping agent is caused by heating to 80 ° C. or higher. However, when the temperature exceeds 120 ° C., the polymerization of the monomer proceeds rapidly. Therefore, the heating for desorption of the capping agent is performed at 80 ° C. It is preferable to carry out at a temperature in the range of ˜120 ° C. This capping agent desorption reaction is usually realized simultaneously in the coating film drying step.
　また、上記反応性官能基（Ｘ）とは、エステル基、エポキシ基、ケトン基、アミノ基、水酸基、などの、前記金属アルコキシドの反応性官能基（Ｙ）と互いに反応して結合する特性を有する官能基である。 In addition, the reactive functional group (X) has a property of reacting with and binding to the reactive functional group (Y) of the metal alkoxide such as an ester group, an epoxy group, a ketone group, an amino group, and a hydroxyl group. It is a functional group having.
　かかる反応性官能基（Ｘ）を有するアクリルモノマーとしては、α，β－エチレン性不飽和モノマー、例えば（メタ）アクリル酸ヒドロキシエチル、（メタ）アクリル酸２－ヒドロキシエチル、（メタ）アクリル酸ヒドロキシプロピル、（メタ）アクリル酸ヒドロキシブチル、メタクリルアルコール、４ヒドロキシブチルアクリレートグリシジル（エポキシ）エーテル、（メタ）アクリル酸ヒドロキシエチルとε－カプロラクトンとの付加物などの水酸基を有するα，β－エチレン性不飽和モノマーなどが挙げられる。 Examples of acrylic monomers having such a reactive functional group (X) include α, β-ethylenically unsaturated monomers such as hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and hydroxy (meth) acrylate. Α, β-ethylenic group having a hydroxyl group such as propyl, hydroxybutyl (meth) acrylate, methacryl alcohol, 4-hydroxybutyl acrylate glycidyl (epoxy) ether, adduct of hydroxyethyl (meth) acrylate and ε-caprolactone And saturated monomers.
　また、「反応性の官能基（Ｘ）を有さない」とは、上記反応性官能基（Ｙ）を有する金属アルコキシドと反応する官能基を有さないことを意味する。
　かかる反応性官能基（Ｘ）を有さないアクリルモノマーとしては、α，β－エチレン性不飽和モノマーとして、（メタ）アクリル酸エステル［例えば（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸－ｎ－プロピル、（メタ）アクリル酸イソプロピル、（メタ）アクリル酸－ｎ－ブチル、（メタ）アクリル酸イソブチル、（メタ）アクリル酸－ｔ－ブチル、（メタ）アクリル酸－２－エチルヘキシル、メタクリル酸ラウリル、アクリル酸フェニル、（メタ）アクリル酸イソボルニル、メタクリル酸シクロヘキシル、（メタ）アクリル酸－ｔ－ブチルシクロヘキシル、（メタ）アクリル酸ジシクロペンタジエニル、（メタ）アクリル酸ジヒドロジシクロペンタジエニル等］、などが挙げられる。 Further, “having no reactive functional group (X)” means having no functional group that reacts with the metal alkoxide having the reactive functional group (Y).
Examples of the acrylic monomer having no reactive functional group (X) include α, β-ethylenically unsaturated monomers such as (meth) acrylate esters [for example, methyl (meth) acrylate, ethyl (meth) acrylate, (Meth) acrylic acid-n-propyl, (meth) acrylic acid isopropyl, (meth) acrylic acid-n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid-t-butyl, (meth) acrylic acid- 2-ethylhexyl, lauryl methacrylate, phenyl acrylate, isobornyl (meth) acrylate, cyclohexyl methacrylate, (meth) acrylate-t-butylcyclohexyl, (meth) acrylate dicyclopentadienyl, (meth) acrylic acid Dihydrodicyclopentadienyl and the like], and the like.
　上述の３種のモノマーを樹脂成分として有する液状体の塗膜を重合、硬化させて得られる３元共重合体層は、３種のモノマーを同時に重合させることにより得てもよいし、「反応性官能基（Ｘ）を有するアクリルモノマー」と「反応性の官能基（Ｘ）を有さないアクリルモノマー」、「反応性官能基（Ｘ）を有するアクリルモノマー」と「反応性官能基（Ｙ)を有する金属アルコキシド」、「反応性官能基（Ｙ)を有する金属アルコキシド」と「反応性の官能基（Ｘ）を有さないアクリルモノマー」の各々の組み合わせで予め２種のモノマーを混合又は重合を部分的に進め半重合した後、残るモノマー成分混合し、重合することにより、得てもよい。これらの重合プロセスの内でも、「反応性官能基（Ｘ）を有するアクリルモノマー」と「反応性の官能基（Ｘ）を有さないアクリルモノマー」の２種のモノマーを混合又は重合を部分的に進め半重合した後、残る「反応性官能基（Ｙ)を有する金属アルコキシド」を混合し、重合するプロセスを採用することが、好ましい。 A ternary copolymer layer obtained by polymerizing and curing a liquid coating film having the above three types of monomers as resin components may be obtained by simultaneously polymerizing the three types of monomers. "Acrylic monomer having reactive functional group (X)" and "acrylic monomer having no reactive functional group (X)", "acrylic monomer having reactive functional group (X)" and "reactive functional group (Y ), “Metal alkoxide having a reactive functional group (Y)” and “acrylic monomer not having a reactive functional group (X)”, or a mixture of two monomers in advance. It may be obtained by partially proceeding the polymerization and semi-polymerizing, then mixing the remaining monomer components and polymerizing. Among these polymerization processes, two types of monomers, “acrylic monomer having reactive functional group (X)” and “acrylic monomer not having reactive functional group (X)”, are mixed or partially polymerized. It is preferable to employ a process in which the remaining “metal alkoxide having a reactive functional group (Y)” is mixed and polymerized after semi-polymerization.
　また、３元共重合体は、最終的に３元共重合体層として基材フィルムの上で塗工して得られるが、各々のモノマーの混合、塗工、重合のタイミングは、混合→重合（半重合）→塗工（残りのモノマーがある場合は、追加混合した後）→重合（乾燥）、または混合→塗工→重合（乾燥）の各々の組み合わせで、得ることができる。 In addition, the terpolymer is finally obtained by coating on a base film as a ternary copolymer layer. The timing of mixing, coating and polymerization of each monomer is mixed → polymerization. (Semi-polymerization) → Coating (after additional mixing if there are remaining monomers) → Polymerization (drying), or Mixing → Coating → Polymerization (drying).
（水系溶媒によるエマルションの調製方法）
　水系溶媒としては、イオン交換水などを用いる。必要に応じてアルコールなどのような有機溶剤を含む水性媒体中に、慣用の分散剤を加えて分散性を向上させることもできる。その後、前記水系溶媒に対して、慣用のホモジナイザー（例えば、マイクロテック・ニチオン社製、商品名「ＮＲ-３００」）を用いて、均一に分散させ、加熱撹拌下、上述組み合わせで３種、または予め２種の組み合わせでモノマーおよび重合開始剤を滴下することにより重合を行うことができる。樹脂成分の濃度としては、３０～６０重量％とすることが好ましい。 (Method for preparing emulsion with aqueous solvent)
As the aqueous solvent, ion exchange water or the like is used. If necessary, a conventional dispersant may be added to an aqueous medium containing an organic solvent such as alcohol to improve the dispersibility. Then, using a conventional homogenizer (for example, trade name “NR-300”, manufactured by Microtech Nichion Co., Ltd.) with respect to the aqueous solvent, the mixture is uniformly dispersed, and three kinds of the above combinations are combined under heating and stirring. Polymerization can be carried out by previously dropping the monomer and the polymerization initiator in a combination of two kinds. The concentration of the resin component is preferably 30 to 60% by weight.
　上記方法により、エマルションを構成する樹脂成分の所望の粒子径からのバラツキが少なくなり、好ましい粒径範囲の樹脂成分粒子を得ることができる。 By the above method, the dispersion of the resin component constituting the emulsion from the desired particle size is reduced, and resin component particles having a preferable particle size range can be obtained.
　上記重合開始剤としては、アゾ系の油性化合物［例えば、アゾビスイソブチロニトリル、２，２’－アゾビス（２－メチルブチロニトリル）、２，２’－アゾビス（２－（２－イミダゾリン－２－イル）プロパン）および２，２’－アゾビス（２，４－ジメチルバレロニトリル）など］；水性化合物［例えば、アニオン系の４，４’－アゾビス（４－シアノ吉草酸）、２，２－アゾビス（Ｎ－（２－カルボキシエチル）－２－メチルプロピオンアミジン）およびカチオン系の２，２’－アゾビス（２－メチルプロピオンアミジン）］；レドックス系の油性過酸化物（例えば、ベンゾイルパーオキサイド、パラクロロベンゾイルパーオキサイド、ラウロイルパーオキサイドおよびｔ－ブチルパーベンゾエートなど）；および水性過酸化物（例えば、過硫酸カリおよび過硫酸アンモニウムなど）が挙げられる。 Examples of the polymerization initiator include azo oily compounds [for example, azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2- (2-imidazoline) -2-yl) propane) and 2,2′-azobis (2,4-dimethylvaleronitrile), etc.]; aqueous compounds [eg anionic 4,4′-azobis (4-cyanovaleric acid), 2, 2-azobis (N- (2-carboxyethyl) -2-methylpropionamidine) and cationic 2,2′-azobis (2-methylpropionamidine)]; redox oily peroxides (eg, benzoyl peroxide) Oxides, parachlorobenzoyl peroxide, lauroyl peroxide and t-butyl perbenzoate); and aqueous peroxides (eg If, like potassium persulfate and ammonium persulfate) and the like.
　なお、先の分散剤以外に、当業者に通常使用されているものや乳化剤、例えば、アントックス（Ａｎｔｏｘ）ＭＳ－６０（商品名：日本乳化剤社製）、エレミノールＪＳ－２（商品名：三洋化成工業社製）、アデカリアソープＮＥ－２０（商品名：旭電化社製）およびアクアロンＨＳ－１０（商品名：第一工業製薬社製）などを併用してもよい。 In addition to the above dispersants, those commonly used by those skilled in the art and emulsifiers such as Antox MS-60 (trade name: manufactured by Nippon Emulsifier Co., Ltd.), Eleminol JS-2 (trade name: Sanyo) Kasei Kogyo Co., Ltd.), ADEKA rear soap NE-20 (trade name: manufactured by Asahi Denka Co., Ltd.) and Aqualon HS-10 (trade name: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) may be used in combination.
　上記慣用の分散剤と上記３種のモノマーからなる樹脂成分との配合比率は、エマルションを調製する場合の慣用の比率に調整すればよい。例えば、固形分質量比で５／９５～２０／８０の範囲に調整すればよい。５／９５未満だと分散粒子が凝集して塊が発生して塗膜の平滑性が損なわれる傾向となり、２０／８０を超えると、膜厚の制御が難しくなる傾向となる。 The blending ratio of the conventional dispersant and the resin component composed of the three types of monomers may be adjusted to a conventional ratio when preparing an emulsion. For example, the solid content may be adjusted to a range of 5/95 to 20/80. When the ratio is less than 5/95, the dispersed particles aggregate to form a lump and the smoothness of the coating film tends to be impaired. When the ratio exceeds 20/80, the film thickness tends to be difficult to control.
　また、分子量を調節するために、ラウリルメルカプタンのようなメルカプタンおよびα－メチルスチレンダイマーなどのような連鎖移動剤を必要に応じて用いてもよい。 In order to adjust the molecular weight, a mercaptan such as lauryl mercaptan and a chain transfer agent such as α-methylstyrene dimer may be used as necessary.
　混合モノマーの重合反応温度は開始剤により決定され、例えば、アゾ系開始剤を用いた場合では６０～９０℃であり、レドックス系開始剤を用いた場合では３０～７０℃で行うことが好ましい。開始剤を用いる場合の配合量は、エマルションの総量に対して、一般に０．１～５質量％であり、好ましくは０．２～２質量％である。 The polymerization reaction temperature of the mixed monomer is determined by the initiator. For example, it is preferably 60 to 90 ° C. when an azo initiator is used, and preferably 30 to 70 ° C. when a redox initiator is used. When the initiator is used, the blending amount is generally 0.1 to 5% by mass, preferably 0.2 to 2% by mass, based on the total amount of the emulsion.
　先に述べたように、モノマーの重合プロセスとしては、「反応性官能基（Ｘ）を有するアクリルモノマー」と「反応性の官能基（Ｘ）を有さないアクリルモノマー」の２種のモノマーを混合又は重合を部分的に進め半重合した後、残る「反応性官能基（Ｙ)を有する金属アルコキシド）」を混合し、重合するプロセスを採用することが、好ましい。 As described above, the monomer polymerization process includes two types of monomers, “an acrylic monomer having a reactive functional group (X)” and “an acrylic monomer having no reactive functional group (X)”. It is preferable to employ a process in which mixing or polymerization is partially advanced and semi-polymerization is performed, and then the remaining “metal alkoxide having a reactive functional group (Y)” is mixed and polymerized.
　予め２種のモノマーを反応させる場合の重合は、１～８時間で行なわれる。 The polymerization in the case of reacting two kinds of monomers in advance is performed in 1 to 8 hours.
　上述の、「反応性官能基（Ｘ）を有するアクリルモノマー」と「反応性の官能基（Ｘ）を有さないアクリルモノマー」の２種のモノマーを部分的に重合（半重合）して得られた２成分半重合樹脂粒子の平均粒子径としては、０．０５～０．３０μｍの範囲であることが好ましい。粒子径が０．０５μｍ未満であると、作業性の改善の効果が小さく、０．３０μｍを上回ると、得られる塗膜の外観が悪化する恐れがある。この粒子径の調節は、例えば、上記２種のモノマー混合物の組成や乳化重合条件を調整することにより可能である。 Obtained by partially polymerizing (semi-polymerizing) two types of monomers, “acrylic monomer having reactive functional group (X)” and “acrylic monomer not having reactive functional group (X)”. The average particle diameter of the obtained two-component semipolymer resin particles is preferably in the range of 0.05 to 0.30 μm. If the particle diameter is less than 0.05 μm, the effect of improving workability is small, and if it exceeds 0.30 μm, the appearance of the resulting coating film may be deteriorated. The particle diameter can be adjusted, for example, by adjusting the composition of the two monomer mixtures and the emulsion polymerization conditions.
　また、上記２成分半重合樹脂粒子の質量平均分子量は６０００～１２０００であることが好ましい。６０００未満だと膜厚みの制御が難しくなる傾向となり、１２０００を超えると塗膜の平滑性が低下する傾向となる。 The mass average molecular weight of the two-component semipolymer resin particles is preferably 6000 to 12000. If it is less than 6000, the control of the film thickness tends to be difficult, and if it exceeds 12,000, the smoothness of the coating film tends to be lowered.
　上述の組成からなるエマルションにおいては、樹脂固形分量が３～２０質量％であることが好ましい。樹脂固形分量が３質量％未満だと、膜厚の制御が難しくなる傾向となり、２０質量％を超えると、塗膜の平滑性が低下する傾向となる。 In the emulsion having the above composition, the resin solid content is preferably 3 to 20% by mass. When the resin solid content is less than 3% by mass, control of the film thickness tends to be difficult, and when it exceeds 20% by mass, the smoothness of the coating film tends to decrease.
（非水系溶媒を用いた樹脂溶液の調製方法）
　非水系溶媒としては、トルエンや酢酸エチルなどの有機溶剤が用いられる。非水系溶媒としては、その他に、キシレン、Ｎ－メチルピロリドン、ブチルアセテート、比較的高沸点の脂肪族及び／もしくは芳香族、ブチルジグリコールアセテート、アセトン等などを適宜用いることもできる。 (Method for preparing resin solution using non-aqueous solvent)
As the non-aqueous solvent, an organic solvent such as toluene or ethyl acetate is used. As the non-aqueous solvent, xylene, N-methylpyrrolidone, butyl acetate, aliphatic and / or aromatics having a relatively high boiling point, butyl diglycol acetate, acetone, and the like can be used as appropriate.
　また、重合開始剤としては、熱でラジカルを発生する開始剤（アゾ系、過酸化物系）が用いられる。 Further, as the polymerization initiator, an initiator (azo-based or peroxide-based) that generates radicals by heat is used.
　前記非水系溶媒に対して、上述の３種、または予め２種の組み合わせのモノマー、および重合開始剤を溶解させて、重合又は部分重合（半重合）の樹脂溶液を得る。樹脂溶液中の樹脂成分の濃度としては、３０～６０重量％とすることが好ましく、さらに好ましくは５０重量％である。 In the non-aqueous solvent, the above-described three kinds or two kinds of combinations of monomers and a polymerization initiator are dissolved to obtain a resin solution for polymerization or partial polymerization (semi-polymerization). The concentration of the resin component in the resin solution is preferably 30 to 60% by weight, more preferably 50% by weight.
　上記液状体には、樹脂成分と溶媒に、さらに、必要に応じて、紫外線散乱剤又は／及び紫外線吸収剤を混合してもよい。紫外線散乱剤としては、酸化亜鉛、酸化チタンなどの微粉末が挙げられる。紫外線吸収剤としては、紫外線吸収能を有する色素や、高濃度ベンゾトリアゾール基を導入したアクリルポリマーなどを挙げることができる。かかる紫外線散乱剤又は／及び紫外線吸収剤を少量添加することで、コート層の耐侯性をさらに向上することができる。コート層が多層構成である場合は、その少なくとも１層に上記紫外線散乱剤又は／及び紫外線吸収剤を混入することが好ましく、２層以上もしくは全ての層に上記紫外線散乱剤又は／及び紫外線吸収剤を混入してもよい。 The liquid material may be mixed with a resin component and a solvent and, if necessary, an ultraviolet scattering agent and / or an ultraviolet absorber. Examples of the ultraviolet scattering agent include fine powders such as zinc oxide and titanium oxide. Examples of the ultraviolet absorber include a dye having an ultraviolet absorbing ability and an acrylic polymer into which a high concentration benzotriazole group is introduced. By adding a small amount of such an ultraviolet scattering agent and / or an ultraviolet absorber, the weather resistance of the coating layer can be further improved. When the coating layer has a multilayer structure, it is preferable to mix the ultraviolet scattering agent and / or ultraviolet absorber in at least one layer, and the ultraviolet scattering agent and / or ultraviolet absorber is mixed in two or more layers or all layers. May be mixed.
　上記液状体としては、エマルション組成の製品が市販されているので、それらを使用することも可能である。市販品としては、例えば、東亞合成株式会社製の「シーラス（商品名）」や日本ペイント株式会社の「シェラスターＭＫ（商品名）」などが挙げられる。 As the liquid material, products having an emulsion composition are commercially available, and it is also possible to use them. Examples of commercially available products include “Cirrus (trade name)” manufactured by Toagosei Co., Ltd. and “Sherastar MK (trade name)” manufactured by Nippon Paint Co., Ltd.
（液状体の塗膜を形成する工程）
　基材フィルム１の少なくともアルミニウム箔２が積層された側（図１では片側）であって、アルミニウム箔２の基材フィルム１が配置された面とは反対面側に、乾燥後の膜厚が６～３５０μｍとなるように、前記液状体の塗膜を形成する。液状体の塗布方法としては、一般に用いられるディッピング法、ロールコーティング法、スクリーン印刷法、スプレー法などの従来公知の手段を用いることができる。また、厚さを均一にコントロールするために、薄いコーティング層を多重に積層して所定の膜厚としてもよい。多重に積層する場合は、先に塗布した層を乾燥させた後に次の層を塗布し、その層を乾燥させて、さらに次の層を塗布することを繰り返す。 (Process of forming a liquid coating film)
On the side of the base film 1 on which at least the aluminum foil 2 is laminated (one side in FIG. 1), the film thickness after drying is on the opposite side of the surface of the aluminum foil 2 where the base film 1 is disposed. The liquid coating film is formed so as to have a thickness of 6 to 350 μm. As a coating method of the liquid material, conventionally known means such as a dipping method, a roll coating method, a screen printing method, a spray method and the like that are generally used can be used. In order to uniformly control the thickness, a plurality of thin coating layers may be laminated to have a predetermined film thickness. In the case of multiple layers, it is repeated that after the previously applied layer is dried, the next layer is applied, the layer is dried, and then the next layer is applied.
（３元共重合体層からなるコート層を形成する工程）
　この工程には、塗膜を乾燥させる塗膜乾燥工程と、乾燥後、最終的に３元共重合体から構成される硬化膜（３元共重合体層）にする乾燥塗膜硬化工程とが、含まれる。 (Step of forming a coat layer comprising a terpolymer layer)
This process includes a coating film drying process for drying the coating film, and a dry coating film curing process for finally forming a cured film (ternary copolymer layer) composed of a ternary copolymer after drying. ,included.
（塗膜乾燥工程）
　この塗膜乾燥工程では、上記液状体の塗膜から溶媒を気化させて、塗膜の形状を安定化させる。乾燥の温度は８０℃～１２０℃が好ましい。８０℃未満では溶媒の気化が不十分になり、１００℃を超えると、塗膜中の未反応モノマーの重合反応が開始される。乾燥時間は、乾燥温度に依存するが、例えば、好ましくは、１００℃で、１０分～１５分である。 (Coating film drying process)
In this coating film drying step, the solvent is vaporized from the liquid coating film to stabilize the shape of the coating film. The drying temperature is preferably 80 ° C to 120 ° C. If it is less than 80 degreeC, vaporization of a solvent will become inadequate, and if it exceeds 100 degreeC, the polymerization reaction of the unreacted monomer in a coating film will be started. Although the drying time depends on the drying temperature, it is preferably 10 to 15 minutes at 100 ° C., for example.
（乾燥塗膜硬化工程）
　乾燥により形状が安定化した塗膜を、塗膜中の未反応モノマーを重合させることにより、硬化させる。未反応モノマーの重合温度は、８０℃～１２０℃が好ましい。８０℃未満では、重合が不十分となり、１２０℃を超えると、ＰＥＴ上に膜形成させる上で、ＰＥＴの収縮が始まり、塗膜も密着性等に悪影響を与えるという不都合が生じる。重合時間は、重合温度に依存するが、例えば、好ましくは、１００℃で、１０分～１５分である。 (Dry paint film curing process)
The coating film whose shape has been stabilized by drying is cured by polymerizing the unreacted monomer in the coating film. The polymerization temperature of the unreacted monomer is preferably 80 ° C to 120 ° C. When the temperature is lower than 80 ° C., the polymerization becomes insufficient, and when the temperature exceeds 120 ° C., when the film is formed on the PET, the PET starts to shrink, and the coating film also adversely affects the adhesion and the like. Although the polymerization time depends on the polymerization temperature, it is preferably 10 to 15 minutes at 100 ° C., for example.
（３元共重合体層の特性及び３元共重合体層をコート層として有するシートの特性）
　上記３元共重合体層からなるコート層３は柔軟性を保ちながらガスバリア性及び耐侯性を有しているので、得られるシートは、太陽電池用裏面保護シートとして、長期信頼性に優れたものとなる。 (Characteristics of ternary copolymer layer and characteristics of sheet having ternary copolymer layer as coating layer)
Since the coating layer 3 comprising the terpolymer layer has gas barrier properties and weather resistance while maintaining flexibility, the obtained sheet has excellent long-term reliability as a back surface protection sheet for solar cells. It becomes.
　従来、水溶性の高分子材料として特許文献２などには、ポリビニルアルコール（ＰＶＡ）が用いられている。ＰＶＡは、その水蒸気透過度が１１００ｇ／ｍ２・２４ｈｒ（測定条件：２５℃、９０％ＲＨ、厚さ２５μｍ）であり、水蒸気バリア性は悪いが、柔軟性に優れている。従来の太陽電池用裏面保護シートにおいては、ガスバリア層とする無機酸化物蒸着膜のみでは屈曲したときのクラックが防止できないため、ＰＶＡのような柔軟性のある高分子膜を積層することにより、対屈曲性を保持しながら、ガスバリア性を確保している。そのため、無機酸化物蒸着膜なしではガスバリア性が不十分であった。すなわち、積層数が多くなり、シートの総計厚みの制御が難しくなっていた。 Conventionally, polyvinyl alcohol (PVA) is used in Patent Document 2 as a water-soluble polymer material. PVA has a water vapor permeability of 1100 g / m 2 · 24 hr (measurement conditions: 25 ° C., 90% RH, thickness of 25 μm), and has a poor water vapor barrier property but excellent flexibility. In the conventional back surface protection sheet for solar cells, cracks when bent only with an inorganic oxide vapor deposition film as a gas barrier layer cannot be prevented. Therefore, by laminating a flexible polymer film such as PVA, Gas barrier properties are secured while maintaining flexibility. Therefore, the gas barrier property was insufficient without an inorganic oxide vapor deposition film. That is, the number of stacked layers is increased, making it difficult to control the total thickness of the sheets.
　本発明では、厚さが３０μｍより薄いアルミニウム箔２とともにガスバリア性を確保するために、コート層３に、金属アルコキシドと共重合できる単量体(モノマー)としてアクリル系を用いている。一般にその重合体のアクリル系樹脂であるポリメチルメタクリレート（ＰＭＭＡ）は、その水蒸気透過度が４１ｇ／ｍ２・２４ｈｒ（測定条件：２５℃、９０％ＲＨ、厚さ２５μｍ）であり、ＰＶＡよりガスバリア性が優れていることが知られている。 In the present invention, in order to ensure gas barrier properties together with the aluminum foil 2 having a thickness of less than 30 μm, the coating layer 3 is made of acrylic as a monomer that can be copolymerized with a metal alkoxide. In general, polymethyl methacrylate (PMMA), which is an acrylic resin of the polymer, has a water vapor permeability of 41 g / m 2 · 24 hr (measurement conditions: 25 ° C., 90% RH, thickness 25 μm), and has a gas barrier higher than that of PVA. It is known that the property is excellent.
　なお、上記ポリビニールアルコール及びポリメチルメタクリレートの水蒸気透過度の測定値は、『「プラスチック材料の各動物性の試験法と評価結果〈５〉」、安田武夫、p.119、vol.51,　No.6、プラスチックス』を出典としたものである。 The measured values of water vapor permeability of the above polyvinyl alcohol and polymethyl methacrylate were ““ Animal testing methods and evaluation results for plastic materials <5> ”, Takeo Yasuda, p.119, vol.51, No. .6, Plastics ”.
　本発明では、コート層３を構成する３元共重合体層のモノマー材料は、反応性官能基（Ｘ）を有するアクリル系モノマー、反応性の官能基（Ｘ）を有さないアクリル系モノマー、および前記反応性官能基（Ｘ）と反応する反応性官能基（Ｙ）を有する金属アルコキシドの３種のモノマーからなる。そして、この３種のモノマーを樹脂成分として有する液状体を形成し、この液状体を成膜化した３元共重合体層をコート層３とする。 In the present invention, the monomer material of the ternary copolymer layer constituting the coat layer 3 is an acrylic monomer having a reactive functional group (X), an acrylic monomer having no reactive functional group (X), And a metal alkoxide having a reactive functional group (Y) that reacts with the reactive functional group (X). Then, a liquid material having these three types of monomers as resin components is formed, and the ternary copolymer layer obtained by forming the liquid material into a film is used as the coating layer 3.
　かかるコート層３を構成する３元共重合体層においては、図４に示すように、２種のアクリル系モノマーがラジカル重合反応により鎖状に結合し、形成されたアクリル系高分子の鎖により柔軟性が保たれる。そして、鎖状のアクリル系高分子中には、一方の反応性官能基（Ｘ）を有するアクリル系モノマー由来の複数の官能基（Ｘ）が間隔を開けて点在しており、その官能基（Ｘ）と金属アルコキシド中の官能基（Ｙ）とが反応して結合する。また、反応性官能基（Ｙ）を有する金属アルコキシド同士の加水分解によってＭ－Ｏ結合が形成され、３元共重合体は網目構造を獲得する。この網目構造により柔軟性と高い水蒸気ガスバリア性及び耐侯性が実現できる。したがって、本発明のシートは、屈曲してもクラックが生じてガスバリア性が著しく劣化することがない。 In the ternary copolymer layer constituting the coat layer 3, as shown in FIG. 4, two kinds of acrylic monomers are combined in a chain by radical polymerization reaction, and the formed acrylic polymer chain Flexibility is maintained. In the chain acrylic polymer, a plurality of functional groups (X) derived from an acrylic monomer having one reactive functional group (X) are scattered at intervals. (X) and the functional group (Y) in the metal alkoxide react and bond. In addition, an MO bond is formed by hydrolysis of metal alkoxides having a reactive functional group (Y), and the terpolymer acquires a network structure. With this network structure, flexibility and high water vapor gas barrier properties and weather resistance can be realized. Therefore, even if the sheet of the present invention is bent, cracks do not occur and the gas barrier property does not deteriorate significantly.
　また、従来品は、耐侯性を有する樹脂フィルムとして、前述のガスバリア層の上にフッ素系樹脂などを接着して用いているが、下記（表１）に示すように、Ｃ－Ｆ結合エネルギーは１１６ｋｃａｌであり、紫外線エネルギーの９６ｋｃａｌに対して、非常に強いが、主鎖となるＣ－Ｃ結合エネルギーは８５ｋｃａｌと紫外線に対して弱い。そのため紫外線による樹脂の劣化が起こる。さらに、ガスバリア層の金属アルコキシドと高分子の複合体は、図５に示すように、金属アルコキシドの加水分解生成物とは化学結合を伴わない単なる高分子との複合体であるため紫外線により高分子の主鎖となるＣ－Ｃ結合が切れてしまうと（図５の×印部分）、高分子部分が紫外線により劣化してしまい、著しく水蒸気ガスバリア性が劣化してしまうという問題がある。 Further, the conventional product is used as a resin film having weather resistance by adhering a fluorine-based resin or the like on the gas barrier layer described above. As shown in the following (Table 1), the C—F bond energy is 116 kcal, which is very strong against the ultraviolet energy of 96 kcal, but the C—C bond energy of the main chain is 85 kcal and weak against ultraviolet rays. Therefore, deterioration of the resin due to ultraviolet rays occurs. Further, as shown in FIG. 5, the composite of the metal alkoxide and polymer in the gas barrier layer is a composite with a simple polymer that is not accompanied by a chemical bond with the hydrolysis product of the metal alkoxide. When the C—C bond that is the main chain of the polymer chain is broken (the x mark portion in FIG. 5), the polymer portion is deteriorated by ultraviolet rays, and the water vapor gas barrier property is remarkably deteriorated.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　これに対し、本発明にかかるシートのコート層に用いられている３元共重合体層では、図６に示すように、紫外線によりアクリル系高分子部分のＣ－Ｃ結合（８５ｋｃａｌ）が切れても（図６の×印部分）、金属アルコキシドによるＭ－Ｏ結合（１０６～１４５ｋｃａｌ）は切れない。また、空気中または高分子中の湿気により金属アルコキシドの加水分解が進み、紫外線によりアクリル系高分子のＣ－Ｃ結合が切れても、Ｍ－Ｏ結合の増大により自己修復できるため、全体として紫外線による劣化はほとんどない。 In contrast, in the terpolymer layer used in the coating layer of the sheet according to the present invention, as shown in FIG. 6, the C—C bond (85 kcal) of the acrylic polymer portion is broken by ultraviolet rays. However, the MO bond (106 to 145 kcal) due to the metal alkoxide is not broken. Even if the hydrolysis of the metal alkoxide progresses due to moisture in the air or in the polymer, and the C—C bond of the acrylic polymer is broken by the ultraviolet ray, self-healing can be performed by increasing the MO bond. There is almost no deterioration by.
　さらに、上記３元共重合体層は、ＰＥＴなどの樹脂とも化学結合を伴って接着するため、接着性は非常に優れており、基材フィルム１と３元共重合体層（コート層３）間での剥離の心配はない。また、金属アルコシドは、水分により加水分解してＭ－Ｏ結合が網目状に形成され、アクリル系高分子の－ＣＨ２－ＣＨＲ－は、一般にほとんど加水分解しないと言われている。それ故、従来のように耐侯性フィルムとガスバリア性を付与した基材フィルムとを接着剤によって接着した構造のシートの欠点、すなわち、長期間使用時における樹脂フィルムの劣化により外部から水分が浸入して接着剤が加水分解により劣化し、フィルム同士が剥離するような問題は、本発明のシートでは起こらない。 Furthermore, since the ternary copolymer layer adheres to a resin such as PET with a chemical bond, the adhesive property is very excellent, and the base film 1 and the ternary copolymer layer (coat layer 3). There is no worry of peeling between them. In addition, it is said that the metal alcoside is hydrolyzed by moisture to form a MO bond in a network, and the —CH 2 —CHR— of the acrylic polymer is generally hardly hydrolyzed. Therefore, the conventional sheet with a structure in which a weather-resistant film and a base film with gas barrier properties are bonded with an adhesive as in the past, that is, moisture has entered from the outside due to deterioration of the resin film during long-term use. Thus, the problem that the adhesive deteriorates due to hydrolysis and the films peel off does not occur in the sheet of the present invention.
　以上のことから、本発明にかかるシートは、柔軟性、超耐侯性、水蒸気ガスバリア性に優れた太陽電池用裏面保護シートとして提供できる。 From the above, the sheet according to the present invention can be provided as a back surface protection sheet for solar cells excellent in flexibility, super weather resistance, and water vapor gas barrier properties.
　以下の実施例では、アクリル系樹脂成分Ａに関して、反応性官能基（Ｙ）を有する金属アルコキシドと、前記反応性官能基（Ｙ）と反応する反応性の官能基（Ｘ）を有するアクリル系モノマーと、反応性の官能基（Ｘ）を有さないアクリル系モノマーとの３種のモノマーのうちの、反応性官能基（Ｙ）を有する金属アルコキシドとして、３－グリシドキシプロピルトリエトキシシラン（実施例１および２に共通）を用いた。また、残りの前記反応性官能基（Ｙ）と反応する反応性の官能基（Ｘ）を有するアクリル系モノマーと、反応性の官能基（Ｘ）を有さないアクリル系モノマーについては、これらモノマーの混合物である市販の製品（日本ペイント株式会社の「シェラスターＭＫ」の主剤）を用いた（実施例１および２に共通）。 In the following examples, regarding the acrylic resin component A, an acrylic monomer having a metal alkoxide having a reactive functional group (Y) and a reactive functional group (X) that reacts with the reactive functional group (Y). And glycidoxypropyltriethoxysilane (3-glycidoxypropyltriethoxysilane) as a metal alkoxide having a reactive functional group (Y) among the three types of monomers of the acrylic monomer having no reactive functional group (X). Common to Examples 1 and 2). For acrylic monomers having reactive functional groups (X) that react with the remaining reactive functional groups (Y) and acrylic monomers having no reactive functional groups (X), these monomers A commercially available product (main ingredient of “Sherastar MK” from Nippon Paint Co., Ltd.) was used (common to Examples 1 and 2).
　前記市販の製品が、前記反応性の官能基（Ｘ）を有するアクリル系モノマーと、反応性の官能基（Ｘ）を有さないアクリル系モノマーの混合物である点については、該製品の乾燥塗膜表面の赤外線全反射吸収スペクトルにより確認することができる。この赤外線全反射吸収スペクトルを図７に示した。 Regarding the point that the commercially available product is a mixture of the acrylic monomer having the reactive functional group (X) and the acrylic monomer not having the reactive functional group (X), dry coating of the product is performed. This can be confirmed by the infrared total reflection absorption spectrum of the film surface. This infrared total reflection absorption spectrum is shown in FIG.
　図７に見るように、波数（wavenumber）３６５０～３２００（ｃｍ－１）、１７６０～１７１５　（ｃｍ－１）、１１５０～１０２５　（ｃｍ－１）に代表的なピークが現れており、これらは、それぞれ、反応性官能基(Ｘ)を有するアクリル系モノマーのカルボン酸（ＣＯＯＨ基）や水酸基（ＯＨ）を含むユニット部のＯＨ基に由来する吸収、反応性官能基(Ｘ)を有しないアクリル系モノマーのエステル（ＣＯＯＲ）を含むユニット部のＣ＝Ｏに由来する吸収、反応性官能基(Ｘ)を有しないアクリル系モノマーのエステル（ＣＯＯＲ）やエーテル(ＣＯＣ)を含むユニット部のＣ－Ｏ－Ｃに由来する吸収である。 As shown in FIG. 7, typical peaks appear at wave numbers 3650 to 3200 (cm −1 ), 1760 to 1715 (cm −1 ), and 1150 to 1025 (cm −1 ). Absorption derived from OH group of unit part including carboxylic acid (COOH group) and hydroxyl group (OH) of acrylic monomer having reactive functional group (X), acrylic system having no reactive functional group (X) Absorption derived from C = O of unit part containing monomer ester (COOR), CO of unit part containing ester (COOR) and ether (COC) of acrylic monomer having no reactive functional group (X) Absorption derived from -C.
　また、以下の実施例において、エチレン系樹脂成分Ｂとして、中央理化工業株式会社製の「アクアテックス９０９（商品名）」を用いた。 Further, in the following examples, “Aquatex 909 (trade name)” manufactured by Chuo Rika Kogyo Co., Ltd. was used as the ethylene-based resin component B.
（実施例１）
　本発明の実施例１では、アクリル系樹脂成分Ａとして、シェラスターＭＫの主剤１５重量部に対して、３－グリシドキシプロピルトリエトキシシラン（１重量部）を配合してなる水系エマルションＡ：１００重量部に対して、エチレン系樹脂成分Ｂとして、エチレン系樹脂成分「アクアテック９０９」（４５重量％）を配合してなる水系エマルションＢを３５重量部配合した液状体を用意した。 Example 1
In Example 1 of the present invention, as an acrylic resin component A, an aqueous emulsion A in which 3-glycidoxypropyltriethoxysilane (1 part by weight) is blended with 15 parts by weight of the main component of Shellaster MK: A liquid body was prepared by blending 35 parts by weight of an aqueous emulsion B obtained by blending the ethylene resin component “AQUATECH 909” (45 wt%) as the ethylene resin component B with respect to 100 parts by weight.
　下記（表２）に示すように、基材フィルムとして厚さ１８８μｍのポリエチレンテレフタレート（ＰＥＴ）フィルム（東洋紡績株式会社製、商品名「エステルフィルム５０００」）を用い、厚さ９μｍのアルミニウム箔を、厚さ５μｍのウレタン系接着剤（東洋インキ株式会社製　商品名「ＴＭＯＦＬＥＸ－５０２」）で前記基材フィルムに接着し、厚さ９μｍのアルミニウム箔をポリエチレンテレフタレート（ＰＥＴ）フィルムに積層した。 As shown below (Table 2), using a polyethylene terephthalate (PET) film (trade name “Ester Film 5000” manufactured by Toyobo Co., Ltd.) having a thickness of 188 μm as a base film, an aluminum foil having a thickness of 9 μm, A 5 μm-thick urethane adhesive (trade name “TMOFLEX-502” manufactured by Toyo Ink Co., Ltd.) was adhered to the base film, and an aluminum foil having a thickness of 9 μm was laminated on a polyethylene terephthalate (PET) film.
　上記基材フィルムのアルミニウム箔を積層した側であって、アルミニウム箔の基材フィルムが配置された面とは反対面側に上記液状体を塗布し、その塗膜を８０℃、１０分間加熱して水系溶媒を気化させて乾燥させた。
　得られた乾燥塗膜を１００℃１０分間加熱して、塗膜を構成する未反応モノマーを重合させて、３元共重合体層（コート層）を得た。得られた膜の厚みは、２０μｍであった。
　以上により、厚さ１８８μｍの基材フィルムの片側面に、９μｍ厚のアルミニウム箔と、２０μｍ厚のコート層（３元共重合体層）が積層されたシート（太陽電池用裏面保護シート：最外層からアルミ箔までの厚さが２９μｍ）を得た。 The liquid material is applied to the side of the base film on which the aluminum foil is laminated and opposite to the surface on which the base film of the aluminum foil is disposed, and the coating film is heated at 80 ° C. for 10 minutes. The aqueous solvent was evaporated and dried.
The obtained dried coating film was heated at 100 ° C. for 10 minutes to polymerize unreacted monomers constituting the coating film, thereby obtaining a ternary copolymer layer (coat layer). The thickness of the obtained film was 20 μm.
As described above, a sheet in which a 9 μm-thick aluminum foil and a 20 μm-thick coat layer (ternary copolymer layer) are laminated on one side of a 188 μm-thick base film (back surface protection sheet for solar cells: outermost layer) To an aluminum foil thickness of 29 μm).
　上記共重合体層の赤外線全反射吸収スペクトルを図８に示した。図８に見るように、波数（wavenumber）３６９０～３２００（ｃｍ－１）、１７６０～１７１５　（ｃｍ－１）、１１５０～１０２５　（ｃｍ－１）、１１００～１０００（ｃｍ－１）にアクリル系共重合体に代表的なピークが現れている。また、エチレン共重合体に関しては、２８４５～２８６５（ｃｍ－１）および２９４０～２９１５（ｃｍ－１）にメチレン（－ＣＨ2－）、１６５０～１７２５（ｃｍ－１）のＣ＝Ｏおよび１２８０（ｃｍ－１）～１３２０のＣ－Ｏおよび２５００～３６００（ｃｍ－１）からなる未反応の残存カルボン酸（－ＣＯＯＨ）に代表的なピークが現れている。 The infrared total reflection absorption spectrum of the copolymer layer is shown in FIG. As shown in FIG. 8, acrylic wave numbers 3690 to 3200 (cm −1 ), 1760 to 1715 (cm −1 ), 1150 to 1025 (cm −1 ), 1100 to 1000 (cm −1 ) A typical peak appears in the polymer. As for the ethylene copolymer, 2845 to 2865 (cm −1 ) and 2940 to 2915 (cm −1 ) include methylene (—CH 2 —), 1650 to 1725 (cm −1 ) C═O and 1280 ( Typical peaks appear in the unreacted residual carboxylic acid (—COOH) consisting of C—O of cm −1 ) to 1320 and 2500 to 3600 (cm −1 ).
　また、アクリル系共重合体が海相を形成し、エチレン系共重合体が島相を形成していることは、走査型電子顕微鏡によって確認することができる。 Further, it can be confirmed by a scanning electron microscope that the acrylic copolymer forms a sea phase and the ethylene copolymer forms an island phase.
　まず、３６９０～３２００（ｃｍ－１）は、反応性官能基(Ｘ)を有するアクリル系モノマーのカルボン酸（ＣＯＯＨ基）や水酸基（ＯＨ）を含むユニット部とアルコキシシラン系モノマーのシラノール基（Ｓｉ－ＯＨ）やエポキシ基の開環反応で生じる水酸基（ＯＨ）を含むユニット部のＯＨに由来する吸収である。また、１７６０～１７１５（ｃｍ－１）は、反応性官能基(Ｘ)を有さないアクリル系モノマーのエステル（ＣＯＯＲ）を含むユニット部のＣ＝Ｏに由来する吸収である。また、１１５０～１０２５（ｃｍ－１）は、反応性官能基(Ｘ)を有しないアクリル系モノマーのエステル（ＣＯＯＲ）やエーテル(ＣＯＣ)を含むユニット部のＣ－Ｏ－Ｃに由来する吸収である。そして、１１００～１０００（ｃｍ－１）は、アルコキシシラン系モノマーのシラノール基同士の脱水縮合反応で生じるシロキサン結合（Ｓｉ－Ｏ）を含むユニット部のＳｉ－Ｏ－Ｓｉに由来する吸収である。 First, 3690 to 3200 (cm −1 ) is a unit part containing a carboxylic acid (COOH group) or a hydroxyl group (OH) of an acrylic monomer having a reactive functional group (X) and a silanol group (Si -OH) or absorption derived from OH in the unit part containing a hydroxyl group (OH) generated by a ring-opening reaction of an epoxy group. Further, 1760 to 1715 (cm −1 ) is an absorption derived from C═O of a unit part containing an ester (COOR) of an acrylic monomer having no reactive functional group (X). Further, 1150 to 1025 (cm −1 ) is an absorption derived from C—O—C of the unit part containing an ester (COOR) or an ether (COC) of an acrylic monomer having no reactive functional group (X). is there. In addition, 1100 to 1000 (cm −1 ) is an absorption derived from Si—O—Si of a unit part including a siloxane bond (Si—O) generated by a dehydration condensation reaction between silanol groups of an alkoxysilane monomer.
　また、２８４５～２２６５（ｃｍ－１）および２９４０～２９１５（ｃｍ－１）は、エチレン系樹脂成分Ｂを構成するメチレン（－ＣＨ2－）に由来する吸収であり、１６５０～１７２５（ｃｍ－１）のＣ＝Ｏおよび１２８０（ｃｍ－１）～１３２０のＣ－Ｏおよび２５００～３６００（ｃｍ－１）は、エチレン系樹脂成分Ｂを構成、存在する未反応の残存カルボン酸（－ＣＯＯＨ）に由来する吸収である。 Further, 2845 to 2265 (cm −1 ) and 2940 to 2915 (cm −1 ) are absorptions derived from methylene (—CH 2 —) constituting the ethylene-based resin component B, and are 1650 to 1725 (cm −1). C = O and 1280 (cm −1 ) to 1320 C—O and 2500 to 3600 (cm −1 ) constitute the ethylene-based resin component B, and the remaining unreacted residual carboxylic acid (—COOH) Absorption derived from.
（実施例２）
　本発明の実施例２では、下記（表２）に示すように、基材フィルムとして厚さ１８８μｍのポリエチレンテレフタレート（ＰＥＴ）フィルム（東洋紡績株式会社製、商品名「エステルフィルム５０００」）を用い、厚さ３０μｍのアルミニウム箔を、厚さ５μｍのウレタン系接着剤（東洋インキ株式会社製　商品名「ＴＭＯＦＬＥＸ－５０２」）で前記基材フィルムに接着し、厚さ３０μｍのアルミニウム箔をポリエチレンテレフタレート（ＰＥＴ）フィルムに積層した。 (Example 2)
In Example 2 of the present invention, as shown in the following (Table 2), a polyethylene terephthalate (PET) film having a thickness of 188 μm (trade name “Ester Film 5000” manufactured by Toyobo Co., Ltd.) as a base film was used. An aluminum foil having a thickness of 30 μm was adhered to the base film with a urethane adhesive having a thickness of 5 μm (trade name “TMOFLEX-502” manufactured by Toyo Ink Co., Ltd.), and the aluminum foil having a thickness of 30 μm was adhered to polyethylene terephthalate (PET). ) Laminated on film.
　上記基材フィルムのアルミニウム箔を積層した側であって、アルミニウム箔の基材フィルムが配置された面とは反対面側に、上記液状体を塗布し、その塗膜を８０℃、１０分間加熱して水系溶媒を気化させて乾燥させた。
　得られた乾燥塗膜を１００℃、１０分間加熱して、塗膜を構成する未反応モノマーを重合させて、３元共重合体層（コート層）を得た。得られた膜の厚みは、２０μｍであった。
　以上により、厚さ１８８μｍの基材フィルムの片側面に、３０μｍ厚のアルミニウム箔と、２０μｍ厚のコート層（３元共重合体層）が積層されてなるシート（太陽電池用裏面保護シート：最外層からアルミ箔までの厚さが５０μｍ）を得た。 The liquid material is applied to the side of the base film on which the aluminum foil is laminated and opposite to the surface on which the base film of the aluminum foil is disposed, and the coating film is heated at 80 ° C. for 10 minutes. Then, the aqueous solvent was evaporated and dried.
The obtained dried coating film was heated at 100 ° C. for 10 minutes to polymerize unreacted monomers constituting the coating film, thereby obtaining a ternary copolymer layer (coat layer). The thickness of the obtained film was 20 μm.
As described above, a sheet obtained by laminating a 30 μm-thick aluminum foil and a 20 μm-thick coat layer (ternary copolymer layer) on one side of a base film having a thickness of 188 μm (back surface protection sheet for solar cell: outermost The thickness from the outer layer to the aluminum foil was 50 μm).
　上記３元共重合体層の赤外線全反射吸収スペクトルをとったところ、図８に示したスペクトルと同一のスペクトルであった。 The infrared total reflection absorption spectrum of the ternary copolymer layer was the same as the spectrum shown in FIG.
（比較例１）
　また、比較例１として、下記（表２）に示すように、基材フィルムとして厚さ１８８μｍのポリエチレンテレフタレート（ＰＥＴ）フィルム（東洋紡績株式会社製、商品名「エステルフィルム５０００」）を用い、厚さ４０μｍのアルミニウム箔を、厚さ５μｍのウレタン系接着剤（東洋インキ株式会社製　商品名「ＴＭＯＦＬＥＸ－５０２」）で前記基材フィルムに接着して、厚さ４０μｍのアルミニウム箔をポリエチレンテレフタレート（ＰＥＴ）フィルムに積層し、さらに厚さ２５μｍのフッ素系ＰＶＦフィルムを厚さ５μｍの前記ウレタン系接着剤でさらにアルミニウム箔上に積層した裏面保護シート（最外層からアルミ箔までの厚さが７０μｍ）を用いた。 (Comparative Example 1)
Moreover, as shown in the following (Table 2) as Comparative Example 1, a polyethylene terephthalate (PET) film (trade name “Ester Film 5000” manufactured by Toyobo Co., Ltd.) having a thickness of 188 μm was used as a base film. A 40 μm thick aluminum foil was adhered to the substrate film with a 5 μm thick urethane adhesive (trade name “TMOFLEX-502” manufactured by Toyo Ink Co., Ltd.), and the 40 μm thick aluminum foil was made of polyethylene terephthalate (PET). ) A back protective sheet (thickness from the outermost layer to the aluminum foil is 70 μm) laminated on the film and further laminated on the aluminum foil with a 25 μm thick fluorine-based PVF film with the 5 μm thick urethane adhesive. Using.
（評価）
　実施例１及び２、ならびに比較例１の各太陽電池用裏面保護シートの性能評価として、水蒸気透過量、引っ張り強度保持率、絶縁耐電圧を測定した。さらに、打抜き穴加工性を目視により評価した。
その結果を（表２）に示す。 (Evaluation)
As performance evaluation of each solar cell back surface protection sheet of Examples 1 and 2 and Comparative Example 1, water vapor transmission rate, tensile strength retention rate, and dielectric strength voltage were measured. Furthermore, the punching hole workability was evaluated visually.
The results are shown in (Table 2).
　上記水蒸気透過量の測定は、ＪＩＳのＺ０２０８に基づき、温度４０℃、湿度９０％ＲＨの条件下、カップ法にて測定を行った。また、引っ張り強度の測定は、ＪＩＳ　Ｋ７１２７に基づき、株式会社島津製作所製の万能試験機（商品名「ＵＨ－５００ｋＮＩ」）を用いて行った。 The water vapor transmission amount was measured by the cup method under the conditions of a temperature of 40 ° C. and a humidity of 90% RH based on JIS Z0208. The tensile strength was measured using a universal testing machine (trade name “UH-500 kNI”) manufactured by Shimadzu Corporation based on JIS K7127.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　実施例１および２のシートの初期水蒸気ガスバリア性は、厚さが４０μｍのアルミニウム箔を用いた比較例１のシートと比較して同等の性能を示している。また、実施例１および２のシートのフレキシブル性は、比較例１のシートと比較して非常に優れ、作業性の向上が図れる。さらに、実施例１および２の打抜き加工性も、穴側面へのアルミニウムのはみ出しがなく、従来品で生じていたアルミニウム箔のバリを原因とする太陽電離モジュールの性能不良を回避することができる。また、実施例１および２のシートでは、アルミニウム箔の厚みを薄くできるので、熱による膨張・収縮を小さく抑えることができ、変形を防止することができる。 The initial water vapor gas barrier properties of the sheets of Examples 1 and 2 are equivalent to those of the sheet of Comparative Example 1 using an aluminum foil having a thickness of 40 μm. Moreover, the flexibility of the sheet | seat of Example 1 and 2 is very excellent compared with the sheet | seat of the comparative example 1, and the improvement of workability | operativity can be aimed at. Further, the punching workability of Examples 1 and 2 also prevents the aluminum ion from protruding into the side surface of the hole, and can avoid the poor performance of the solar ionization module caused by the burr of the aluminum foil that has occurred in the conventional product. Moreover, in the sheet | seat of Example 1 and 2, since the thickness of aluminum foil can be made thin, the expansion | swelling and shrinkage | contraction by heat can be suppressed small, and a deformation | transformation can be prevented.
　以上のことから、本発明によれば、水蒸気ガスバリア性に優れ、長期耐侯性及び耐久性に優れた太陽電池用裏面保護シートを提供することができる。 From the above, according to the present invention, it is possible to provide a back protective sheet for solar cells that is excellent in water vapor gas barrier properties and excellent in long-term weather resistance and durability.
　１　基材フィルム
　２　アルミニウム箔
　３　コート層 1 Base film 2 Aluminum foil 3 Coat layer

Claims (2)

  1. 　少なくとも１層からなる基材フィルムと、該基材フィルムの片側又は両側に配置されるアルミニウム箔と、該アルミニウム箔の前記基材フィルムが配置された面とは反対面側に配置される少なくとも１層からなる１以上のコート層とを有してなる太陽電池用裏面保護シートであって、
    　前記コート層が、反応性官能基（Ｙ）を有する金属アルコキシドと、前記反応性官能基（Ｙ）と反応する反応性の官能基（Ｘ）を有するアクリル系モノマーと、反応性の官能基（Ｘ）を有さないアクリル系モノマーとからなる樹脂成分を有する液状体の塗膜を硬化してなる３元共重合体層であることを特徴とする太陽電池用裏面保護シート。     A base film composed of at least one layer; an aluminum foil disposed on one or both sides of the base film; and at least one disposed on a surface opposite to the surface of the aluminum foil on which the base film is disposed. A back protective sheet for a solar cell comprising one or more coat layers comprising layers,
    The coating layer includes a metal alkoxide having a reactive functional group (Y), an acrylic monomer having a reactive functional group (X) that reacts with the reactive functional group (Y), and a reactive functional group ( A back protective sheet for solar cells, which is a ternary copolymer layer obtained by curing a coating film of a liquid material having a resin component composed of an acrylic monomer having no X).
  2. 　前記金属アルコキシドは、一般式：ＹＭ（ＯＲ）３、ＹＲＭ（ＯＲ）２、ＹＲ２Ｍ（ＯＲ）（式中、Ｍは金属、Ｒはアルキル基、Ｙは反応性を有する官能基を示す）で表される化合物であることを特徴とする請求項１に記載の太陽電池用裏面保護シート。 The metal alkoxide has a general formula: YM (OR) 3 , YRM (OR) 2 , YR 2 M (OR) (wherein M represents a metal, R represents an alkyl group, and Y represents a reactive functional group). The back surface protection sheet for solar cells of Claim 1 characterized by the above-mentioned.
PCT/JP2012/050115 2011-01-14 2012-01-05 Solar-cell back-side protective sheet WO2012096217A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011006479A JP2012151152A (en) 2011-01-14 2011-01-14 Rear surface protective sheet for solar cell
JP2011-006479 2011-01-14

Publications (1)

Publication Number Publication Date
WO2012096217A1 true WO2012096217A1 (en) 2012-07-19

Family

ID=46507117

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/050115 WO2012096217A1 (en) 2011-01-14 2012-01-05 Solar-cell back-side protective sheet

Country Status (3)

Country Link
JP (1) JP2012151152A (en)
TW (1) TW201233539A (en)
WO (1) WO2012096217A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI684285B (en) * 2014-12-26 2020-02-01 日商材料概念股份有限公司 Solar battery module and manufacturing method thereof

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002083988A (en) * 2000-09-08 2002-03-22 Dainippon Printing Co Ltd Rear surface protection sheet for solar cell module and solar cell module using the same
WO2006126511A1 (en) * 2005-05-24 2006-11-30 Mitsui Chemicals, Inc. Gas barrier composition, coating film, methods for producing those, and multilayer body
JP2008254193A (en) * 2007-03-30 2008-10-23 Tohcello Co Ltd Gas barrier laminate
WO2009133827A1 (en) * 2008-04-28 2009-11-05 旭化成ケミカルズ株式会社 Laminate for solar battery back-sheet, and back-sheet comprising the same
JP2010016286A (en) * 2008-07-07 2010-01-21 Toppan Printing Co Ltd Sheet for sealing backside of solar battery
WO2010058695A1 (en) * 2008-11-21 2010-05-27 テクノポリマー株式会社 Backside protective sheet for solar cell and solar cell module provided with same
WO2011007700A1 (en) * 2009-07-15 2011-01-20 日本発條株式会社 Backside protective sheet for solar cells and process for production of same

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002083988A (en) * 2000-09-08 2002-03-22 Dainippon Printing Co Ltd Rear surface protection sheet for solar cell module and solar cell module using the same
WO2006126511A1 (en) * 2005-05-24 2006-11-30 Mitsui Chemicals, Inc. Gas barrier composition, coating film, methods for producing those, and multilayer body
JP2008254193A (en) * 2007-03-30 2008-10-23 Tohcello Co Ltd Gas barrier laminate
WO2009133827A1 (en) * 2008-04-28 2009-11-05 旭化成ケミカルズ株式会社 Laminate for solar battery back-sheet, and back-sheet comprising the same
JP2010016286A (en) * 2008-07-07 2010-01-21 Toppan Printing Co Ltd Sheet for sealing backside of solar battery
WO2010058695A1 (en) * 2008-11-21 2010-05-27 テクノポリマー株式会社 Backside protective sheet for solar cell and solar cell module provided with same
WO2011007700A1 (en) * 2009-07-15 2011-01-20 日本発條株式会社 Backside protective sheet for solar cells and process for production of same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI684285B (en) * 2014-12-26 2020-02-01 日商材料概念股份有限公司 Solar battery module and manufacturing method thereof

Also Published As

Publication number Publication date
TW201233539A (en) 2012-08-16
JP2012151152A (en) 2012-08-09

Similar Documents

Publication Publication Date Title
JP4734480B2 (en) Back protection sheet for solar cell and method for producing the same
JP4734468B1 (en) Substrate for solar cell module and method for producing the same
JP4924779B2 (en) Easy adhesive for solar cell back surface protective sheet, solar cell back surface protective sheet, and solar cell module
TWI469869B (en) Multi-layered film and photovoltaic module including the same
WO2012004962A1 (en) Highly-adhesive agent for a solar-cell back-side protective sheet, solar-cell back-side protective sheet, and solar cell module
CN103502001B (en) Multilayer film and the photovoltaic module comprising this multilayer film
WO2012133748A1 (en) Highly adhesive back protective sheet and a solar cell module using same
JP2014015566A (en) Coating agent composition and backside protective sheet for solar cell
JP5974294B2 (en) Easy adhesive for solar cell back surface protective sheet, solar cell back surface protective sheet, and solar cell module
WO2012096217A1 (en) Solar-cell back-side protective sheet
WO2012096215A1 (en) Solar-cell back-side protective sheet
WO2012096216A1 (en) Solar-cell back-side protective sheet
JP5899754B2 (en) Easy-adhesive layer composition and easy-adhesive back surface protective sheet using the same
JP5867064B2 (en) Easy adhesive for solar cell back surface protective sheet, solar cell back surface protective sheet, and solar cell module
JP5853668B2 (en) Easy adhesive for solar cell back surface protective sheet, solar cell back surface protective sheet, and solar cell module
JP6361235B2 (en) Shielding sheet, and back surface protection sheet for solar cell module and solar cell module using the same
JP2009107235A (en) Laminate
WO2012096218A1 (en) Solar-cell back-side protective sheet
JP6003490B2 (en) Easy-adhesive layer composition and white back surface protective sheet using the same
JP2001217441A (en) Solar cell module
JP2017028107A (en) Backside protective sheet for solar cell module and solar cell module using the same
JP2011178115A (en) Gas barrier laminate and sheet for solar cell using the same

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12734465

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12734465

Country of ref document: EP

Kind code of ref document: A1