WO2012029465A1 - Front surface protective sheet for solar cell and solar cell module produced using same - Google Patents

Front surface protective sheet for solar cell and solar cell module produced using same Download PDF

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Publication number
WO2012029465A1
WO2012029465A1 PCT/JP2011/067228 JP2011067228W WO2012029465A1 WO 2012029465 A1 WO2012029465 A1 WO 2012029465A1 JP 2011067228 W JP2011067228 W JP 2011067228W WO 2012029465 A1 WO2012029465 A1 WO 2012029465A1
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Prior art keywords
solar cell
protective sheet
layer
front protective
ethylene
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PCT/JP2011/067228
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French (fr)
Japanese (ja)
Inventor
治 赤池
谷口　浩一郎
潤 西岡
亮太 山本
陽 宮下
綾　哲也
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三菱樹脂株式会社
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Publication of WO2012029465A1 publication Critical patent/WO2012029465A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/08—Copolymers of ethene
    • C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing more than three carbon atoms
    • C08L23/0815—Copolymers of ethene with aliphatic 1-olefins
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2203/00—Applications
    • C08L2203/20—Applications use in electrical or conductive gadgets
    • C08L2203/204—Applications use in electrical or conductive gadgets use in solar cells
    • 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 relates to a front protective sheet used as a front protective member for a cell for solar cells, and a laminate of the same and a sealing material, and more particularly, a solar cell comprising a resin layer having flexibility, moisture resistance and weather resistance.
  • Solar cell front protective sheet effective for weight reduction and durability improvement, and laminate of solar cell front protective sheet / encapsulant laminated with a sealing material effective for improving transparency and heat resistance
  • the present invention relates to a lightweight and highly durable solar cell using the solar cell front protective sheet or laminate.
  • a solar cell has a configuration in which solar cell cells are sealed between a front surface protective sheet and a back surface protective sheet from the light receiving surface side by a sealing film such as an ethylene-vinyl acetate copolymer, polyethylene, or polypropylene film.
  • a sealing film such as an ethylene-vinyl acetate copolymer, polyethylene, or polypropylene film.
  • Such a solar cell is usually manufactured by laminating a front protective sheet, a sealing film, a power generation element, a sealing film, and a back protective sheet in this order and bonding them together by heating and melting.
  • As a front protective sheet for solar cells it is required to have excellent durability against ultraviolet rays.
  • the sealing material has flexibility and impact resistance to protect the solar cell element, heat resistance when the solar cell module generates heat, and transparency to efficiently reach the solar cell element (all Light transmittance, etc.), durability, dimensional stability, flame retardancy, water vapor barrier properties, etc. are mainly required.
  • a glass plate is used as the surface-side protection member.
  • the glass plate is excellent in light resistance and moisture resistance, but has a drawback that it is heavy and weak against impact and easily cracked.
  • Patent Document 1 a transparent resin film is used for the front protective sheet to solve the problem of damage due to weight and impact, and the front protective sheet is combined with a resin film having good weather resistance and moisture resistance. Therefore, a solar cell front protective sheet effective for improving the durability of the solar cell has been proposed.
  • the front protective sheet for solar cells described in Patent Document 1 when the weather resistant layer and the moisture-proof layer are bonded to the front protective sheet using an adhesive, it is difficult to increase the thickness of the adhesive from the viewpoint of productivity. In some cases, the moisture-proof layer is damaged by falling objects on the light-receiving surface, thereby deteriorating the moisture-proof function.
  • the front protective sheet is made of an ethylene-vinyl acetate copolymer, which is generally used as a sealing material for solar electronics, as a film for laminating a weatherproof layer and a moisture-proof layer.
  • An adhesive is proposed (Patent Document 2).
  • Patent Document 2 A method for preventing deterioration of the moisture-proof function due to falling objects on the battery has been proposed (Patent Document 2).
  • Patent Document 2 when an ethylene-vinyl acetate copolymer is used, crosslinking is usually performed using a crosslinking agent such as an organic peroxide for the purpose of imparting heat resistance to the copolymer. Deterioration of appearance and deterioration of moisture-proof layer occur.
  • the ethylene-vinyl acetate copolymer contains an acetic acid, a crosslinking agent, a crosslinking aid, etc. generated by hydrolysis of the ethylene-vinyl acetate copolymer during long-term use.
  • the resin and the adhesive are deteriorated and peeling at the interface in the layer occurs.
  • ethylene-vinyl acetate copolymer is used for the sealing material, stress due to cross-linking shrinkage is generated above and below the moisture-proof layer in vacuum lamination for manufacturing solar cells, and the barrier property of the moisture-proof layer is significantly reduced. There was also a problem of letting it go.
  • a solar cell encapsulant made of an ⁇ -olefin polymer that does not require crosslinking and does not generate acetic acid (Patent Document 3), or a polymer made of at least one polyolefin copolymer and at least one crystalline polyolefin
  • a solar cell encapsulating material (Patent Document 4) comprising a blend or a polymer alloy is disclosed.
  • the above Patent Document 4 specifically describes a polymer blend of a low melting point ethylene-vinyl acetate copolymer and a high melting point ethylene-vinyl acetate copolymer (see Example 1), ethylene-methacrylic acid copolymer.
  • Polymer blends of coalesced and general purpose crystalline polyethylene (see Example 2) and polymer blends of ethylene-methyl acrylate copolymer and general purpose crystalline polypropylene (see Example 3) are disclosed.
  • the resin composition comprising a polymer mainly composed of propylene specifically used in Patent Document 3 has insufficient transparency (total light transmittance: 83.2% (see Examples). )))
  • total light transmittance 83.2% (see Examples).
  • each polymer blend used in Patent Document 4 is not necessarily excellent in transparency, and there is still a problem in balancing the flexibility, heat resistance and transparency.
  • the use of such a polymer for both the front protective sheet and the encapsulant leads to a significant deterioration in light transmittance, which seriously affects the performance of the solar cell.
  • an object of the present invention is to solve the above-mentioned conventional problems in a protective sheet used as a transparent protective member for a solar cell, and to prevent deterioration of a resin layer having a moisture-proof performance constituting a part of the sheet
  • a resin layer with a good balance between flexibility, heat resistance and transparency, it prevents deterioration of the moisture resistance of the front protective sheet due to falling objects, etc., and transparency and long-term high moisture resistance
  • the present inventors have obtained a resin layer containing an ethylene- ⁇ -olefin random copolymer having specific thermal characteristics and an ethylene- ⁇ -olefin block copolymer having specific thermal characteristics.
  • the weather-resistant layer (A) and the moisture-proof layer (B) are divided into an ethylene- ⁇ -olefin random copolymer (C-1) that satisfies the following condition (1) and an ethylene- ⁇ that satisfies the following condition (2): -A front protective sheet for solar cells, which is laminated through a flexible layer (C) containing an olefin block copolymer (C-2), and the front protective sheet for solar cells, An ethylene- ⁇ -olefin random copolymer (D-1) satisfying the condition (1) and an ethylene- ⁇ -olefin block copolymer (D-2) satisfying the condition (2) below are contained.
  • the present invention relates to a solar cell front protective sheet / sealing material laminate formed by laminating a sealing material (D).
  • a sealing material D
  • the heat of crystal fusion measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 70 J / g.
  • the crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or more, and the crystal melting heat amount is 5 to 70 J / g.
  • the present invention also relates to a solar cell module and a solar cell produced using the solar cell front protective sheet or solar cell front protective sheet / sealing material laminate of the present invention.
  • a front protection sheet for solar cells which has both transparency and long-term high moisture resistance and weather resistance, and is effective in reducing the weight and durability of solar cells, and the front protection sheet for solar cells
  • a sealing material laminate can be provided, and a lightweight, highly durable solar cell module and a solar cell using the solar cell front protective sheet or solar cell front protective sheet / sealing material laminate Can be provided.
  • the weather-resistant layer (A) in the present invention is a layer that is rich in flexibility, excellent in heat resistance, moisture resistance, and UV durability, and preferably highly transparent, and aims to maintain the solar cell front protective sheet and the surface appearance.
  • Used as The weather resistance of the weather resistant layer is preferably such that there is little decrease in mechanical properties and total light transmittance in a weather resistance test conducted according to JIS K7350, and mechanical properties and total light transmittance after 5000 hours have passed. Are preferable, and those having no decrease in mechanical properties and total light transmittance after 10000 hours are particularly preferable.
  • Examples of the material for the weathering layer (A) include polytetrafluoroethylene (PTFE), 4-fluorinated ethylene-perchloroalkoxy copolymer (PFA), and 4-fluorinated ethylene-6-fluorinated propylene copolymer.
  • PTFE polytetrafluoroethylene
  • PFA 4-fluorinated ethylene-perchloroalkoxy copolymer
  • HPC 4-fluorinated ethylene-6-fluorinated propylene copolymer
  • Fluoropolymer films such as (FEP), 2-ethylene-4-fluoroethylene copolymer (ETFE), poly-3-fluoroethylene chloride (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF),
  • FEP 2-ethylene-4-fluoroethylene copolymer
  • PCTFE poly-3-fluoroethylene chloride
  • PVDF polyvinylidene fluoride
  • PVDF polyvinylidene fluoride
  • PVDF polyvinylidene fluoride
  • PVDF polyvinylidene fluoride
  • PVDF polyvinylidene fluoride
  • PVDF polyvinylidene fluoride
  • PVDF polyvinylidene fluoride
  • PVF polyvinyl fluoride
  • EFE 2-ethylene-4-fluoroethylene copolymer
  • FEP 4-fluoroethylene Ren-6-fluorinated propylene copolymer
  • said ultraviolet absorber the thing similar to the below-mentioned ultraviolet absorber which can be contained in a flexible layer can be used.
  • the said resin can also be used by 1 type, it can also be used in combination of 2 or more type.
  • the thickness of the weather resistant layer (A) is generally about 20 to 200 ⁇ m, preferably 30 to 120 ⁇ m, more preferably 40 to 80 ⁇ m from the viewpoint of ease of handling as a film and cost.
  • the moisture-proof layer (B) in the present invention is a resin layer that is used to prevent moisture, internal conductors due to permeation of water, rusting of electrodes, and the like, and is preferably a resin layer that is highly transparent and excellent in moisture resistance. Although there is no particular limitation, those having at least one inorganic oxide coating film on at least one surface of the base material layer are preferably used.
  • the base material layer is preferably a thermoplastic polymer film, and any material can be used without particular limitation as long as it is a resin that can be used for ordinary packaging materials.
  • polyolefins such as homopolymers or copolymers such as ethylene, propylene and butene, amorphous polyolefins such as cyclic polyolefins, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), nylon 6 , Nylon 66, nylon 12, polyamide such as copolymer nylon, ethylene-vinyl acetate copolymer partial hydrolyzate (EVOH), polyimide, polyetherimide, polysulfone, polyethersulfone, polyetheretherketone, polycarbonate, polyvinyl Examples include butyral, polyarylate, fluororesin, acrylate resin, and biodegradable resin.
  • polyesters, polyamides, and polyolefins are preferable from the viewpoints of film properties and cost.
  • polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are particularly preferable from the viewpoint of film properties.
  • the base material layer is a known additive such as an antistatic agent, a light blocking agent, an ultraviolet absorber, a plasticizer, a lubricant, a filler, a colorant, a stabilizer, a lubricant, a crosslinking agent, an antiblocking agent, An antioxidant etc. can be contained.
  • the thermoplastic polymer film as the base material layer is formed by using the above raw materials, but when used as a base material, it may be unstretched or stretched. Good. Moreover, you may laminate
  • Such a base material layer can be produced by a conventionally known method.
  • the raw material resin is melted by an extruder, extruded by an annular die or a T die, and rapidly cooled to be oriented substantially amorphously. No unstretched film can be produced.
  • a multilayer die it is possible to produce a single layer film made of one kind of resin, a multilayer film made of one kind of resin, a multilayer film made of various kinds of resins, and the like.
  • the unstretched film is subjected to a known method such as uniaxial stretching, tenter sequential biaxial stretching, tenter simultaneous biaxial stretching, tubular simultaneous biaxial stretching, or the like.
  • a film stretched in at least a uniaxial direction can be produced by stretching in a direction (horizontal axis) perpendicular thereto.
  • the draw ratio can be arbitrarily set, but the heat shrinkage at 150 ° C. is preferably 0.01 to 5%, more preferably 0.01 to 2%.
  • a biaxially stretched polyethylene naphthalate film, a polyethylene terephthalate and / or a coextruded biaxially stretched film of polyethylene naphthalate and other plastics are preferable.
  • anchor coating agent examples include solvent-based or water-soluble polyester resins, isocyanate resins, urethane resins, acrylic resins, vinyl-modified resins, vinyl alcohol resins, vinyl butyral resins, ethylene vinyl alcohol resins, nitrocellulose resins, oxazoline group-containing resins, carbodiimides.
  • a group-containing resin, a methylene group-containing resin, an epoxy group-containing resin, a modified styrene resin, a modified silicon resin, an alkyl titanate, or the like can be used alone or in combination of two or more.
  • silane coupling agents titanium coupling agents, light blocking agents, ultraviolet absorbers, stabilizers, lubricants, antiblocking agents, antioxidants, etc., or they are copolymerized with the above resins Things can be used.
  • the anchor coat layer As a method for forming the anchor coat layer, a known coating method is appropriately adopted. For example, any method such as a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, a spray or a coating method using a brush can be used. Alternatively, the vapor deposition layer may be immersed in a resin solution. After coating, the solvent can be evaporated using a known drying method such as hot air drying or hot roll drying at a temperature of about 80 to 200 ° C. or infrared drying. Moreover, in order to improve water resistance and durability, the crosslinking process by electron beam irradiation can also be performed. Further, the formation of the anchor coat layer may be a method performed in the middle of the base material layer production line (in-line) or a method performed after the base material layer is manufactured (off-line).
  • a known coating method is appropriately adopted. For example, any method such as a reverse roll coater, a gravure coater, a rod coater, an air
  • a substrate in which a coating film of a metal such as aluminum is formed on the base material layer is known.
  • a metal such as aluminum is applied to a solar cell, current may leak. Therefore, an inorganic oxide coating film such as silica / alumina is preferably used.
  • any of a vapor deposition method and a coating method can be used, but a vapor deposition method is preferred in that a uniform thin film having a high gas barrier property can be obtained.
  • This vapor deposition method includes methods such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). Examples of physical vapor deposition include vacuum deposition, ion plating, and sputtering, and chemical vapor deposition includes plasma CVD using plasma and a catalyst that thermally decomposes a material gas using a heated catalyst body. Examples include chemical vapor deposition (Cat-CVD).
  • Examples of the inorganic substance constituting the inorganic oxide coating film include silicon, aluminum, magnesium, zinc, tin, nickel, titanium, hydrogenated carbon, and the like, or oxides, carbides, nitrides, or mixtures thereof.
  • diamond like carbon mainly composed of silicon oxide, aluminum oxide, and hydrogenated carbon is preferable.
  • silicon oxide, silicon nitride, silicon oxynitride, and aluminum oxide are preferable in that high gas barrier properties can be stably maintained.
  • the thickness of the coating film is preferably 40 to 1000 nm, more preferably 80 to 800 nm, and still more preferably 160 to 600 nm from the viewpoint of stable moistureproof performance.
  • the thickness of the base material layer is generally about 5 to 100 ⁇ m, preferably 8 to 50 ⁇ m, more preferably 12 to 25 ⁇ m from the viewpoint of productivity and ease of handling.
  • the thickness of the moisture-proof layer (A) is generally about 6 to 100 ⁇ m, preferably 9 to 50 ⁇ m, more preferably 12 to 25 ⁇ m from the viewpoint of productivity and ease of handling.
  • the flexible layer (C) in the present invention is used between the weather-resistant layer (A) and the moisture-proof layer (B).
  • a resin layer made of an ethylene- ⁇ -olefin copolymer is used because it is highly transparent, rich in flexibility, and excellent in heat resistance and hydrolysis. It is possible to use a resin composition containing an ethylene- ⁇ -olefin random copolymer having specific thermal characteristics and an ethylene- ⁇ -olefin block copolymer having specific thermal characteristics. This is necessary from the viewpoint of expressing flexibility.
  • the ethylene- ⁇ -olefin random copolymer having specific thermal characteristics is an ethylene- ⁇ -olefin random copolymer (C-1) that satisfies the following condition (1), and has specific thermal characteristics.
  • the ethylene- ⁇ -olefin block copolymer possessed is an ethylene- ⁇ -olefin block copolymer (C-2) that satisfies the following condition (2).
  • the heat of crystal fusion measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 70 J / g.
  • the crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or more, and the crystal melting heat amount is 5 to 70 J / g.
  • the heat resistance of the front protective sheet for solar cells is the characteristics of the ethylene- ⁇ -olefin random copolymer (C-1) constituting the flexible layer (C) (crystal melting peak temperature, crystal melting heat, MFR, molecular weight, etc.) And ethylene- ⁇ -olefin block copolymer (C-2), which are affected by various properties (crystal melting peak temperature, crystal melting heat, MFR, molecular weight, etc.), especially ethylene- ⁇ -olefin block copolymer The crystal melting peak temperature of (C-2) is strongly affected.
  • the temperature of a solar cell module rises to about 85 to 90 ° C. due to heat generated during power generation or radiant heat of sunlight, but the ethylene- ⁇ -olefin block copolymer (C— If the crystal melting peak temperature of 2) is 100 ° C. or higher, the heat resistance of the front protective sheet for solar cells can be ensured.
  • the upper limit temperature of the crystal melting peak temperature of the ethylene- ⁇ -olefin block copolymer (C-2) is 145 ° C., it can be sealed without excessively high temperature in the sealing step of the solar cell element. This is preferable because it is possible.
  • Types of ⁇ -olefins used in each of the ethylene- ⁇ -olefin random copolymer (C-1) and the ethylene- ⁇ -olefin block copolymer (C-2) constituting the flexible layer (C) in the present invention May be the same or different, but in the present invention, the same is the compatibility when mixed and the transparency of the front protective sheet, that is, the photoelectric conversion efficiency of the solar cell. Is preferable.
  • the total of (C-1) and (C-2) is 100 parts by mass.
  • the mixing (containing) mass ratio is in the above range because a flexible layer (C) having an excellent balance of flexibility, heat resistance, transparency and the like can be easily obtained.
  • the flexibility of the flexible layer (C) in the present invention may be appropriately adjusted in consideration of the shape, thickness, installation location, etc. of the applied solar cell.
  • the vibration frequency in dynamic viscoelasticity measurement is 10 Hz
  • the storage elastic modulus (E ′) at 20 ° C. is preferably 1 to 2000 MPa. From the viewpoint of protection of the solar cell element, the storage elastic modulus (E ′) is preferably lower.
  • the pressure is more preferably 3 to 1000 MPa, further preferably 5 to 500 MPa, and particularly preferably 10 to 100 MPa.
  • the heat resistance of the flexible layer (C) in the present invention is determined by various characteristics of the ethylene- ⁇ -olefin random copolymer (C-1) (crystal melting peak temperature, crystal melting heat amount, MFR, molecular weight, etc.) and ethylene- ⁇ - Although it is affected by various properties (crystal melting peak temperature, crystal melting heat, MFR, molecular weight, etc.) of the olefin block copolymer (C-2), in particular, ethylene- ⁇ -olefin block copolymer (C-2) The crystal melting peak temperature is strongly affected. As described above, if the crystal melting peak temperature of the ethylene- ⁇ -olefin block copolymer (C-2) in the flexible layer (C) is 100 ° C.
  • the heat resistance of the flexible layer (C) in the present invention is ensured. I can do it. And since a front surface protection sheet has the lowest heat resistance and elastic modulus of a flexible layer (C) in the layer which comprises a member, a flexible layer (C) determines the performance about the heat resistance of a front surface protection sheet.
  • the heat resistance of the flexible layer (C) is 0 mm between white plate glass having a thickness of 3 mm (size: length 75 mm, width 25 mm) and an aluminum plate having a thickness of 5 mm (size: length 120 mm, width 60 mm).
  • .5mm sheet-like flexible layer (C) is stacked, and a sample is laminated and pressed using a vacuum press machine at 150 ° C for 15 minutes, and the sample is inclined at 60 ° C in a 100 ° C constant temperature bath. Then, after observing the state after 500 hours, the case where the glass did not deviate from the initial reference position was evaluated as ⁇ , and the case where the glass deviated from the initial reference position or the sheet was melted was evaluated as x.
  • the total light transmittance of the flexible layer (C) in the present invention is not so much when applied to a type of solar cell to be applied, for example, an amorphous thin film silicon type or a portion that does not block sunlight reaching the solar electronic element. Although it may not be regarded as important, it is usually preferably 85% or more, more preferably 87% or more, taking into consideration the photoelectric conversion efficiency of the solar cell and handling properties when various members are superimposed, 90% % Or more is more preferable.
  • the flexibility, heat resistance and transparency of the flexible layer (C) in the present invention are likely to be contradictory characteristics. Specifically, if the crystallinity of the resin composition used for improving flexibility is excessively lowered, the heat resistance is lowered and becomes insufficient. On the other hand, if the crystallinity of the resin composition used for improving the heat resistance is excessively improved, the transparency is lowered and becomes insufficient.
  • the balance is used as an index of flexibility, the vibration frequency is 10 Hz in dynamic viscoelasticity measurement, the storage elastic modulus (E ′) at a temperature of 20 ° C., and the heating rate is 10 ° C. in differential scanning calorimetry as an index of heat resistance.
  • the total light transmittance is used as an index of crystal melting peak temperature and transparency measured in terms of / min, three indices are storage elastic modulus (E ′) of 1 to 2000 MPa, and crystal melting peak temperature is 100 ° C. or higher.
  • the total light transmittance is preferably 85% or more, the storage elastic modulus (E ′) is 5 to 500 MPa, the crystal melting peak temperature is 105 to 145 ° C., and the total light transmittance is more preferably 85% or more.
  • the storage elastic modulus (E ′) is 10 to 100 MPa, the crystal melting peak temperature is 110 to 145 ° C., and the total light transmittance is 87% or more.
  • the thickness of the flexible layer (C) is about 50 to 100 ⁇ m in order to suppress damage to the moisture-proof layer due to falling objects and deterioration of the moisture-proof function, and is preferably 150 to 750 ⁇ m, preferably 300 to 500 ⁇ m from the viewpoint of handling. Further preferred.
  • the melt flow rate (MFR) of the ethylene- ⁇ -olefin random copolymer (C-1) used in the present invention is not particularly limited, but is usually MFR (JIS K7210, temperature: 190 ° C., load) 21.18N) is about 0.5 to 100 g / 10 min, preferably 2 to 50 g / 10 min, more preferably 3 to 30 g / 10 min.
  • the MFR may be selected in consideration of the formability when the sheet is formed.
  • the MFR is preferably a relatively low value, specifically about 0.5 to 5 g / 10 min from the handling property when the sheet is peeled off from the molding roll.
  • MFR is preferably 2 to 50 g / 10 min, more preferably 3 to 30 g / 10 min from the viewpoint of reducing the extrusion load and increasing the extrusion rate.
  • the ethylene- ⁇ -olefin random copolymer (C-1) used in the present invention has a heat of crystal melting of 0 to 70 J / g measured at a heating rate of 10 ° C./min in the condition (1) differential scanning calorimetry. It is important to satisfy, preferably 5 to 70 J / g, more preferably 10 to 65 J / g. If it is in this range, since the softness
  • general-purpose high-density polyethylene is about 170 to 220 J / g
  • low-density polyethylene resin LDPE
  • linear low-density polyethylene LLDPE
  • the crystal melting peak temperature of the ethylene- ⁇ -olefin random copolymer (C-1) used in the present invention is not particularly limited, but is usually less than 100 ° C., preferably 30 to 90. ° C.
  • crystal melting peak temperature general-purpose high-density polyethylene (HDPE) is about 130 to 145 ° C.
  • low-density polyethylene resin (LDPE) and linear low-density polyethylene (LLDPE) are 100 to 125. It is about °C. That is, with the ethylene- ⁇ -olefin random copolymer (C-1) used alone in the present invention, the crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or higher, In addition, it is difficult to achieve a crystal melting heat quantity of 5 to 70 J / g.
  • ethylene- ⁇ -olefin random copolymer (C-1) used in the present invention include trade names “Engage”, “Affinity” manufactured by Dow Chemical Co., Ltd., Mitsui Examples include trade names “TAFMER A”, “TAFMER P” manufactured by Kagaku Co., Ltd., and “kernel” manufactured by Nippon Polyethylene Co., Ltd.
  • the melt flow rate (MFR) of the ethylene- ⁇ -olefin block copolymer (C-2) used in the present invention is not particularly limited, but is usually MFR (JIS K7210, temperature: 190 ° C., load) : 21.18N) is about 0.5 to 100 g / 10 min, more preferably 1 to 50 g / 10 min, still more preferably 1 to 30 g / 10 min, and particularly preferably 1 to 10 g / 10 min.
  • the ethylene- ⁇ -olefin block copolymer (C-2) used in the present invention has a crystal melting peak temperature of 100 ° C. or higher measured at a heating rate of 10 ° C./min in differential scanning calorimetry, It is important that the heat of fusion satisfies 5 to 70 J / g (condition (2)).
  • the crystal melting peak temperature is preferably 105 ° C. or higher, more preferably 110 ° C. or higher, and the upper limit is usually 145 ° C.
  • the heat of crystal melting is preferably 10 to 60 J / g, more preferably 15 to 55 J / g.
  • the block structure of the ethylene- ⁇ -olefin block copolymer (C-2) used in the present invention is not particularly limited as long as the above-described condition (2) is satisfied, but flexibility, heat resistance, Two or more, preferably three or more segments or blocks having different comonomer contents, crystallinity, density, crystal melting peak temperature (melting point Tm), or glass transition temperature (Tg) from the viewpoint of balancing such as transparency
  • a multi-block structure containing Specific examples include a completely symmetric block, an asymmetric block, and a tapered block structure (a structure in which the ratio of the block structure gradually increases in the main chain).
  • 2005/090425 (WO2005 / 090425), International Publication No. 2005/090426 (WO2005 / 090426), and International Publication No.2005. / 090427 pamphlet (WO2005 / 090427) or the like can be employed.
  • the ethylene- ⁇ -olefin block copolymer having the multi-block structure will be described in detail below.
  • the ethylene- ⁇ -olefin block copolymer having a multiblock structure can be suitably used in the present invention, and an ethylene-octene multiblock copolymer having 1-octene as a copolymerization component as an ⁇ -olefin is preferable.
  • As the block copolymer an almost non-crystalline soft segment copolymerized with a large amount of octene component (about 15 to 20 mol%) with respect to ethylene and a small amount of octene component (about 2 mol% with respect to ethylene).
  • a multiblock copolymer having two or more highly crystalline hard segments each having a copolymerized crystal melting peak temperature of 110 to 145 ° C. is preferred.
  • chain length and ratio of these soft segments and hard segments By controlling the chain length and ratio of these soft segments and hard segments, both flexibility and heat resistance can be achieved.
  • trade name “Infuse” manufactured by Dow Chemical Co., Ltd. may be mentioned.
  • the melt flow rate (MFR) of the ethylene- ⁇ -olefin block copolymer (C-2) used in the present invention is not particularly limited, but usually MFR (JIS K7210, temperature: 190 ° C., load) : 21.18N) is about 0.5 to 100 g / 10 min, more preferably 1 to 50 g / 10 min, still more preferably 1 to 30 g / 10 min, and particularly preferably 1 to 10 g / 10 min.
  • the MFR may be selected in consideration of the formability when the sheet is formed. Specifically, when calendering a sheet, the MFR is preferably relatively low, specifically about 0.5 to 5 g / 10 min from the handling property when the sheet is peeled off from the molding roll, In the case of extrusion molding using a T die, an MFR of 1 to 30 g / 10 min is preferably used from the viewpoint of reducing the extrusion load and increasing the extrusion amount. Further, from the viewpoint of adhesion and ease of wraparound when sealing the solar cell element (cell), an MFR of 3 to 50 g / 10 min is preferably used.
  • the contents of the ethylene- ⁇ -olefin random copolymer (C-1) and the ethylene- ⁇ -olefin block copolymer (C-2) in the flexible layer (C) are flexibility, heat resistance, From the viewpoint of having an excellent balance such as transparency, it is preferably 50 to 99% by mass, 1 to 50% by mass, more preferably 60 to 98% by mass, 2 to 40% by mass, respectively. Preferably, they are 70 to 97% by mass and 3 to 30% by mass.
  • the front protective sheet for a solar cell of the present invention is formed by laminating the above-mentioned weather resistant layer (A) and moisture-proof layer (B) via a flexible layer (C).
  • the protective sheet / encapsulant laminate is formed by laminating the encapsulant (D) on the solar cell front protective sheet.
  • the encapsulant (D) is used to encapsulate the solar cell element and, like the flexible layer (B), an ethylene- ⁇ -olefin random copolymer (D-) that satisfies the following condition (1): 1) and an ethylene- ⁇ -olefin block copolymer (D-2) satisfying the following condition (2).
  • the heat of crystal fusion measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 70 J / g.
  • the crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or more, and the crystal melting heat amount is 5 to 70 J / g.
  • the ethylene- ⁇ -olefin random copolymer (D-1) satisfying the condition (1) the ethylene- ⁇ -olefin random copolymer (C-1) used for the front protective sheet is used.
  • the same ethylene- ⁇ -olefin block copolymer (D-2) that satisfies the condition (2) can be used as the ethylene-
  • the types of olefins may be the same or different, but in the present invention, the same olefin is compatible when mixed and the transparency of the front protective sheet, that is, the solar cell. It is preferable because photoelectric conversion efficiency is improved.
  • the flexible layer (C ) can contain other similar resins or additives.
  • Properties of the obtained sealing material such as storage elastic modulus, heat resistance, total light transmittance, and the relationship thereof are the same as those of the layer (C).
  • the sealing material (D) those having the same composition and properties as the flexible layer (C) are preferable from the viewpoint of preventing the moisture-proof performance from being lowered when a solar cell module described later is produced.
  • the thickness of the sealing material (D) is not particularly limited, but is usually about 0.05 to 1 mm, preferably 0.1 to 0.7 mm, more preferably 0.3 to 0.5 mm. It is used in the form of a sheet.
  • the solar cell front protective sheet and solar cell front protective sheet / sealing material laminate according to the present invention have various physical properties (flexibility, heat resistance, transparency, adhesiveness, etc.) without departing from the gist of the present invention. ),
  • the above-mentioned ethylene- ⁇ -olefin random copolymer (C-1) or (D-1) or ethylene- ⁇ -olefin block copolymer (C-) Resins other than 2) or (D-2) can be mixed.
  • the resin examples include other polyolefin resins and various elastomers (olefin-based, styrene-based, etc.), polar groups such as carboxyl groups, amino groups, imide groups, hydroxyl groups, epoxy groups, oxazoline groups, thiol groups, silanol groups, and the like. And a resin modified with a tackifier resin.
  • the tackifying resin examples include petroleum resins, terpene resins, coumarone-indene resins, rosin resins, and hydrogenated derivatives thereof.
  • the petroleum resin includes cyclopentadiene or an alicyclic petroleum resin derived from a dimer thereof and an aromatic petroleum resin derived from a C 9 component
  • the terpene resin includes terpene resin and terpene derived from ⁇ -pinene.
  • -Phenol resin, and examples of rosin resins include rosin resins such as gum rosin and wood rosin, and esterified rosin resins modified with glycerin, pentaerythritol, and the like.
  • the tackifying resin can be obtained with various softening temperatures mainly depending on the molecular weight, but when mixed with the copolymer (C-1) and copolymer (C-2) described above, Aliphatic ring having a softening temperature of 100 to 150 ° C., preferably 120 to 140 ° C., in view of compatibility, color tone and thermal stability when mixed with polymer (D-1) and copolymer (D-2) Particularly preferred are hydrogenated derivatives of formula petroleum resins.
  • a flexible layer In (C) or the sealing material (D) when a resin other than the above-mentioned copolymer (C-1) or copolymer (C-2), or a resin other than copolymer (D-1) or copolymer (D-2) is mixed, a flexible layer In (C) or the sealing material (D), when the resin composition is usually 100 parts by mass, it is preferably 20 parts by mass or less, and more preferably 10 parts by mass or less.
  • additives can be added to the solar cell front protective sheet and the solar cell front protective sheet / sealing material laminate of the present invention as necessary.
  • the additive include a silane coupling agent, an antioxidant, an ultraviolet absorber, a weathering stabilizer, a light diffusing agent, a nucleating agent, a pigment (for example, a white pigment), a flame retardant, and a discoloration preventing agent.
  • a silane coupling agent, an antioxidant, an ultraviolet absorber, and a weathering stabilizer is added for reasons described later.
  • a crosslinking agent and / or a crosslinking aid may be blended.
  • silane coupling agents include compounds having a hydrolyzable group such as an alkoxy group together with an unsaturated group such as a vinyl group, an acryloxy group or a methacryloxy group, an amino group or an epoxy group.
  • Specific examples of the silane coupling agent include N- ( ⁇ -aminoethyl) - ⁇ -aminopropyltrimethoxysilane, N- ( ⁇ -aminoethyl) - ⁇ -aminopropylmethyldimethoxysilane, and ⁇ -aminopropyltriethoxy.
  • Examples thereof include silane, ⁇ -glycidoxypropyltrimethoxysilane, and ⁇ -methacryloxypropyltrimethoxysilane.
  • ⁇ -glycidoxypropyltrimethoxysilane and ⁇ -methacryloxypropyltrimethoxysilane are preferably used because of good adhesiveness and little discoloration such as yellowing.
  • the amount of the silane coupling agent added is usually about 0.1 to 5% by mass in the solar cell front protective sheet or in each resin layer constituting the solar cell front protective sheet / sealing material laminate. It is preferable to add 0.2 to 3% by mass.
  • a coupling agent such as an organic titanate compound can be effectively used.
  • antioxidant various commercial products can be applied, and various types such as monophenol type, bisphenol type, polymer type phenol type, sulfur type and phosphite type can be exemplified.
  • monophenols include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, and 2,6-di-tert-butyl-4-ethylphenol.
  • bisphenols examples include 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4 '-Thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidene-bis- (3-methyl-6-tert-butylphenol), 3,9-bis [ ⁇ 1,1-dimethyl- 2- ⁇ - (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy ⁇ ethyl ⁇ 2,4,9,10-tetraoxaspiro] 5,5-undecane.
  • Examples of the high molecular phenolic group include 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3 , 5-di-tert-butyl-4-bidoxybenzyl) benzene, tetrakis- ⁇ methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate ⁇ methane, bis ⁇ (3,3′-bis-4′-hydroxy-3′-tert-butylphenyl) butyric acid ⁇ glycol ester, 1,3,5-tris (3 ′, 5′-di-tert-butyl-4 '-Hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione, triphenol (vitamin E) and the like.
  • sulfur-based compounds examples include dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiopropionate.
  • phosphites include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, Crick neopentanetetrayl bis (octadecyl phosphite), tris (mono and / or di) phenyl phosphite, diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10 pho
  • phenol-based and phosphite-based antioxidants are preferably used in view of the effect of the antioxidant, thermal stability, economy and the like, and it is more preferable to use a combination of both.
  • the addition amount of the antioxidant is usually about 0.1 to 1% by mass in the front protective sheet for solar cells or in each resin layer constituting the front protective sheet / sealant laminate for solar cells. 0.2 to 0.5% by mass is preferably added.
  • UV absorber various commercially available products can be applied, and various types such as benzophenone-based, benzotriazole-based, triazine-based, and salicylic acid ester-based materials can be exemplified.
  • benzophenone ultraviolet absorbers include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-n.
  • benzotriazole ultraviolet absorber examples include hydroxyphenyl-substituted benzotriazole compounds such as 2- (2-hydroxy-5-methylphenyl) benzotriazole and 2- (2-hydroxy-5-tert-butylphenyl).
  • Benzotriazole 2- (2-hydroxy-3,5-dimethylphenyl) benzotriazole, 2- (2-methyl-4-hydroxyphenyl) benzotriazole, 2- (2-hydroxy-3-methyl-5-t- Butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-amylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, etc. be able to.
  • triazine ultraviolet absorbers examples include 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 2- ( Examples include 4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) phenol.
  • salicylic acid esters include phenyl salicylate and p-octylphenyl salicylate.
  • the addition amount of the ultraviolet absorber is usually about 0.01 to 2.0% by mass in the front protective sheet for solar cells or in each resin layer constituting the front protective sheet / sealant laminate for solar cells. It is preferable to add 0.05 to 0.5% by mass.
  • Hindered amine light stabilizers are preferably used as the weather stabilizer for imparting weather resistance in addition to the above ultraviolet absorbers.
  • a hindered amine light stabilizer does not absorb ultraviolet rays like an ultraviolet absorber, but exhibits a remarkable synergistic effect when used together with an ultraviolet absorber.
  • hindered amine light stabilizers include dimethyl-1- (2-hydroxyethyl) succinate-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [ ⁇ 6- (1,1 , 3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl ⁇ ⁇ (2,2,6,6-tetramethyl-4-piperidyl) imino ⁇ hexamethylene ⁇ 2, 2,6,6-tetramethyl-4-piperidyl ⁇ imino ⁇ ], N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2, 6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3 , 5-Di-tert-4 Hydroxybenzyl) -2-
  • the amount of the hindered amine light stabilizer added is usually 0.01 to 0.5 in the solar cell front protective sheet or in each resin layer constituting the solar cell front protective sheet / sealing material laminate. It is about mass%, and it is preferable to add 0.05 to 0.3 mass%.
  • the weathering layer (A), moisture-proof layer (B), flexible layer (C) and sealing material (D) used in the present invention known methods such as a single screw extruder and a multi-screw extruder are used. It has melt mixing equipment such as a Banbury mixer and a kneader, and can adopt an extrusion casting method using a T-die or a calendar method, and is not particularly limited. From the viewpoint of properties and the like, an extrusion casting method using a T die is preferably used.
  • the molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film-forming properties of the resin composition to be used, but is generally 130 to 300 ° C., preferably 150 to 250 ° C.
  • Various additives such as silane coupling agents, antioxidants, UV absorbers, and weathering stabilizers may be dry blended with the resin in advance and then supplied to the hopper.
  • the master batch may be supplied after being prepared, or a master batch in which only the additive is previously concentrated in the resin may be prepared and supplied.
  • the thickness of the front protective sheet for solar cells of the present invention is not particularly limited, but is usually about 0.05 to 1 mm, preferably 0.1 to 0.7 mm.
  • the front protective sheet for a solar cell of the present invention is formed by removing the film-formed weatherable layer (A), moisture-proof layer (B) and flexible layer (C) with a vacuum laminator at a temperature of 120 to 150 ° C. according to a conventional method. It can be produced by heat-pressure bonding with a gas time of 2 to 15 minutes, a press pressure of 0.5 to 1 atm, and a press time of 8 to 45 minutes.
  • the thickness of the front protective sheet / sealing material laminate is not particularly limited, but is usually about 0.12 to 2.3 mm, preferably about 0.3 to 1.6 mm. Preferably, it is used in the form of a sheet of about 0.60 to 1.2 mm.
  • the front protective sheet / sealing material laminate is prepared by subjecting the above-mentioned weathered layer (A), flexible layer (B), moisture-proof layer (C) and sealing material (D) to a temperature by a vacuum laminator according to a conventional method. It can be produced by heat and pressure bonding at 120 to 170 ° C., a degassing time of 2 to 15 minutes, a pressing pressure of 0.5 to 1 atm, and a pressing time of 8 to 45 minutes.
  • the front protective sheet of the present invention has the weather resistant layer (A) as its surface side and the moisture proof layer (B) as its inner surface side, that is, from the front surface (upper part), the weather resistant layer (A ), Flexible layer (C), and moisture-proof layer (B) are preferably arranged in this order, and the front protective sheet / sealing material laminate is formed from the front surface (upper part), the weather resistant layer (A), and the flexible layer (C).
  • the moisture-proof layer (B) and the sealing material (D) are preferably arranged in this order.
  • the example of the front protective sheet for a solar cell shown in FIG. 1 is obtained by laminating a weather-resistant layer 1 and a moisture-proof layer 2 via a flexible layer 3 and bonding them together.
  • the solar cell front protective sheet / sealing material laminate of the present invention is laminated with a sheet-like sealing material (D) after forming a weather-resistant layer (A), a flexible layer (C) and a moisture-proof layer (B).
  • the example of the solar cell front protective sheet / sealing material laminate shown in FIG. 2 is obtained by laminating a weather-resistant layer 1, a flexible layer 3, a moisture-proof layer 2, and a sealing resin layer 4.
  • the solar cell front protective sheet / sealing material laminate according to the present invention has the above-described configuration.
  • the moisture-proof layer (B) is provided as described above.
  • positioning between a flexible layer (C) and a sheet-like sealing material (D) it becomes possible to achieve a high light transmittance and to reduce a moisture-proof fall remarkably.
  • the solar cell front protective sheet and the solar cell front protective sheet / sealing material laminate in the present invention preferably both have high transparency, and the total light transmittance is the type of solar cell to be applied, for example, amorphous.
  • the total light transmittance is the type of solar cell to be applied, for example, amorphous.
  • it is preferably 84% or more, and more preferably 85% or more.
  • the total light transmittance can be measured according to JIS K7105 as described later.
  • the configuration of the front protective sheet in particular, flexibility, heat resistance and transparency are well balanced.
  • the flexible layer (C) on the outer side (front surface) of the moisture-proof layer (B)
  • the structure of the front protective sheet / sealing material laminate in particular, the flexible layer (C) is used as the moisture-proof layer (B).
  • a moisture-proof layer (B) between the flexible layer (C) and the sealing material (D) it is possible to prevent deterioration of the moisture-proof layer by ensuring the flexibility of the front protective sheet.
  • long-term high moisture resistance and weather resistance can be achieved.
  • the moisture-proof performance is evaluated according to the conditions of JIS Z0222 “Moisture permeability test method for moisture-proof packaging containers” and JIS Z0208 “Moisture permeability test method for moisture-proof packaging materials (cup method)”, and specifically evaluated by the method described below. Can do.
  • the solar cell module can be manufactured by fixing the solar cell element together with the back sheet using the front protective sheet for solar cells or the front protective sheet / sealing material laminate of the present invention.
  • various types can be exemplified.
  • the solar cell front protective sheet of the present invention preferably, the solar cell front protective sheet of the present invention and the sealing are used.
  • a solar cell module manufactured using a stopper, a solar cell element, and a lower protective material is mentioned. Specifically, an upper protective material (front protective sheet for solar cell of the present invention) / sealing material ( Sealing resin layer) / solar cell element / sealing material (sealing resin layer) / lower protective material (see FIG.
  • the front surface protection sheet / sealing material laminate of the present invention when using the front surface protection sheet / sealing material laminate of the present invention, preferably, the front surface protection sheet / sealing material layered body for solar cells, the solar cell element, and the lower protection material of the present invention are used.
  • the solar cell module produced by the above method can be used.
  • a structure see FIG.
  • the solar cell front protective sheet / sealing material laminate of the present invention is formed on the solar cell element formed on the inner peripheral surface of the lower protective material
  • an amorphous solar cell element produced by sputtering or the like on a fluororesin-based transparent protective material Such as forming a sealant and lower protective material Or the like can be mentioned the formation.
  • Examples of solar cell elements include single crystal silicon type, polycrystalline silicon type, amorphous silicon type, III-V group and II-VI group compound semiconductor types such as gallium-arsenic, copper-indium-selenium, cadmium-tellurium, Examples include a dye sensitizing type and an organic thin film type.
  • each member which comprises the solar cell module produced using the front surface protection sheet for solar cells of this invention or a front surface protection sheet and a sealing material laminated body although it does not specifically limit,
  • a sealing material For example, an ethylene-vinyl acetate copolymer may be mentioned, but it is preferable to use the sealing material (D).
  • the sealing material is preferably subjected to surface treatment such as corona treatment on at least one surface thereof from the viewpoint of ensuring adhesion to the front protective sheet.
  • the lower protective material is a single layer or multilayer sheet such as a metal or various thermoplastic resin layers, for example, a metal such as tin, aluminum or stainless steel, an inorganic material such as glass, a polyester, an inorganic vapor deposition polyester, a fluorine-containing resin. And a single-layer or multilayer protective material such as polyolefin.
  • the surface of the upper and / or lower protective material can be subjected to a known surface treatment such as a primer treatment or a corona treatment in order to improve the adhesion to the sealing material or other members.
  • the solar cell front protective sheet 10 As shown in FIG. 3, the solar cell front protective sheet 10, the sealing resin layer 12A, the solar cell elements 14A and 14B, the sealing resin layer 12B, and the back sheet 16 are laminated in order from the sunlight receiving side. Further, a junction box 18 (a terminal box for connecting wiring for taking out the electricity generated from the solar cell element) is bonded to the lower surface of the back sheet 16. The solar cell elements 14A and 14B are connected by a wiring 20 in order to conduct the generated current to the outside. The wiring 20 is taken out through a through hole (not shown) provided in the back sheet 16 and connected to the junction box 18.
  • a known manufacturing method can be applied, and is not particularly limited, but generally, a front protective sheet, a sealing resin layer, a solar cell element, a sealing resin layer, a lower part It has the process of laminating
  • the solar cell module produced by using the front protective sheet for solar cells or the front protective sheet / sealing material laminate of the present invention is a small solar cell typified by a mobile device depending on the type of solar cell applied and the module shape. It can be applied to various uses regardless of whether it is indoors or outdoors, such as batteries and large solar cells installed on the roof or rooftop.
  • this solar cell protective sheet, encapsulant, power generation element, encapsulant, and back surface protective sheet are removed at a temperature of 120 to 150 ° C. with a vacuum laminator according to a conventional method.
  • Manufacture can be easily performed by heat-pressure bonding with a gas time of 2 to 15 minutes, a press pressure of 0.5 to 1 atm, and a press time of 8 to 45 minutes.
  • Crystal melting peak temperature (Tm) (Physical property measurement)
  • Tm Crystal melting peak temperature
  • a differential scanning calorimeter manufactured by PerkinElmer Co., Ltd., trade name “Pyris1 DSC”, according to JIS K7121 about 10 mg of the sample was heated from ⁇ 40 ° C. to 200 ° C. at a heating rate of 10 ° C./min.
  • the temperature was lowered to ⁇ 40 ° C. at a cooling rate of 10 ° C./min, and again from the thermogram measured when the temperature was raised to 200 ° C. at a heating rate of 10 ° C./min ( Tm) (° C.) was determined.
  • each flexible layer, and the moisture-proof layer are stacked between two pieces of white plate glass (size: length 75 mm, width 25 mm) having a thickness of 3 mm, and 150 ° C. for 15 minutes using a vacuum press machine.
  • a sample that was laminated and pressed under the above conditions was prepared, the total light transmittance was measured according to JIS K7105, the value was described, and the results evaluated according to the following criteria were also shown.
  • ( ⁇ ) Total light transmittance is 90% or more
  • ⁇ ) Total light transmittance is 85% or more and less than 90%
  • ⁇ Total light transmittance is less than 85% or clearly cloudy (not measured) )
  • a flexible layer is layered between two pieces of 3 mm thick white sheet glass (size: length 75 mm, width 25 mm), and a sample that is laminated and pressed using a vacuum press machine at 150 ° C. for 15 minutes is prepared.
  • the sample was installed at an inclination of 60 degrees in a constant temperature bath at 100 ° C., the state after 500 hours was observed, and evaluated according to the following criteria.
  • ⁇ The glass did not deviate from the initial reference position
  • ⁇ The glass deviated from the initial reference position or the sheet melted
  • Moisture-proof performance is evaluated by the following method according to the conditions of JIS Z0222 “Test method for moisture permeability of moisture-proof packaging containers” and JIS Z0208 “Test method for moisture permeability of amount of moisture-proof packaging material (cup method)”. be able to. Using two laminated films or laminates each having a moisture permeable area of 10.0 cm x 10.0 cm square, a bag containing about 20 g of anhydrous calcium chloride as a hygroscopic agent and sealed on all sides is produced.
  • Moisture retention (barrier stability) Laminated weather-proof layer, flexible layer, moisture-proof layer and sealing resin layer using a vacuum laminator LM-30x30 manufactured by NPC Corporation at 150 ° C for 15 minutes and laminated the front protective sheet sealing material An article was made. Then, the water vapor transmission rate of the produced front protective sheet sealing material laminate and the water vapor transmission rate of the moisture-proof layer of the following constituent film (2) were respectively measured according to the above-mentioned JIS Z0208 “Moisture permeability test method for moisture-proof packaging material amount (cup method ) "And evaluated moisture-proof performance. With respect to the moisture proof performance of the moisture proof layer of the following constituent film (2), the degree of decrease in the moisture proof performance of the obtained laminate was evaluated as ⁇ , within 50%, ⁇ over 50% and 100%, and x over 100%.
  • the resin composition constituting the sheet is 80 parts by mass of ( ⁇ -1) and an ethylene-octene block copolymer (manufactured by Dow Chemical Co., Ltd., trade name: Infuse D9507.15, Octene content: 16.4 mol% (44 mass%), MFR: 5, Tm: 123 ° C., ⁇ Hm: 21 J / g) (hereinafter abbreviated as ⁇ -2) 20 mass parts
  • ⁇ -2 ethylene-octene block copolymer
  • ( ⁇ -1) is an ethylene-propylene-hexene ternary random copolymer (manufactured by Nippon Polyethylene Co., Ltd., trade name: Kernel KJ640T, propylene content: 7.4 mol% (10 wt%), hexene content: 4.4 mol% (10 wt%), MFR: 30, Tm: 53 ° C., ⁇ Hm: 58 J / g
  • the flexible layer 3 having a thickness of 0.5 mm was obtained in the same manner as the flexible layer 1 except that the thickness was changed to (hereinafter abbreviated as ⁇ -2).
  • the resin composition constituting the sheet is an ethylene-octene random copolymer (manufactured by Prime Polymer Co., Ltd.), a general-purpose crystalline polyethylene resin. , Trade name: Moretech 0238CN, Octene content: 1 mol% (4 mass%), MFR: 2.1, Tm: 121 ° C., ⁇ Hm: 127 J / g (hereinafter abbreviated as P-1) Except for the above, a flexible layer 5 having a thickness of 0.5 mm was obtained in the same manner as the flexible layer 1.
  • Flexible layer 9 A flexible layer 9 was obtained in the same manner as the flexible layer 1 except that ⁇ -1 and ⁇ -1 in the preparation of the flexible layer 1 were used and the thickness of the sheet was changed to 0.3 mm. The results of measuring the thickness, composition, total light transmittance, heat resistance and flexibility (storage modulus) of each of the obtained flexible layers 1 to 9 are summarized in Table 1 below.
  • Example 1 The prepared weather-resistant layer, flexible layer 1 and moisture-proof layer were laminated by a conventional method at 150 ° C. for 15 minutes using a vacuum laminator LM-30x30 manufactured by NPC Co., Ltd. to prepare a front protective sheet 1. Then, the total light transmittance was measured by the method similar to the flexible layer shown above using the produced front surface protection sheet 1, and the result is shown in Table 2. Furthermore, when moisture resistance was measured by the following method, the value was 0.24 g / (m 2 ⁇ day).
  • Example 2 The weatherproof layer, the flexible layer 2 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce the front protective sheet 2 and the total light transmittance was measured in the same manner. The results are shown in Table 2. Moreover, when moisture-proof property was measured like Example 1, the value was 0.24 g / (m ⁇ 2 > * day).
  • Example 3 The weatherproof layer, the flexible layer 3 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce the front protective sheet 3 and the total light transmittance was measured. The results are shown in Table 2. Moreover, when moisture-proof property was measured like Example 1, the value was 0.21 g / (m ⁇ 2 > * day).
  • Comparative Example 1 The weather resistant layer, the flexible layer 4 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce the front protective sheet 4 and the total light transmittance was measured. The results are shown in Table 2.
  • Comparative Example 2 The weather-resistant layer, the flexible layer 5 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce the front protective sheet 5 and the total light transmittance was measured. The results are shown in Table 2.
  • Comparative Example 3 The weatherproof layer, the flexible layer 6 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to prepare the front protective sheet 6 and the total light transmittance was measured. The results are shown in Table 2.
  • Comparative Example 4 The weatherproof layer, the flexible layer 7 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce a front protective sheet 7 and the total light transmittance was measured. The results are shown in Table 2.
  • Comparative Example 5 The weather-resistant layer, the flexible layer 8 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce the front protective sheet 8 and the total light transmittance was measured. The results are shown in Table 2.
  • the front protective sheet of the present invention obtained as described above has both high moisture resistance and weather resistance and is excellent in transparency.
  • the flexible layers 1 to 3 used in the front protective sheet of the present invention have a good balance between flexibility, heat resistance and transparency required for protecting the moisture-proof layer. As shown, it had a sufficient thickness. Therefore, the front protective sheets of Examples 1 to 3 produced using the flexible layers 1 to 3 have not only high moisture resistance and weather resistance, but also excellent transparency. It can withstand use under high temperature and inclined conditions, and can be protected from impact from falling objects. On the other hand, the flexible layers 4 and 8 are inferior in heat resistance, and when used under high temperature / inclined conditions, it has been revealed that the flexible layers 4 and 8 are deviated from the reference value or the sheet is melted.
  • the flexible layer cannot fulfill its role, and it is considered that the moisture-proof layer is not sufficiently protected. That is, it is not preferable as a material for a solar cell member that is expected to be used under high temperature and inclined conditions.
  • the flexible layers 5 to 7 were inferior in flexibility (storage modulus), indicating that the moisture-proof layer was insufficiently protected. Therefore, also in the front protective sheets of Comparative Examples 2 to 4 produced using the flexible layers 5 to 7, it is considered that the flexible layer cannot fulfill its role and the moisture-proof layer is not sufficiently protected.
  • Example 4 The above-prepared weathering layer, flexible layer 1, moisture-proof layer and flexible layer 1 are laminated in this order by a conventional method at 150 ° C. for 15 minutes using a vacuum laminating machine LM-30x30 manufactured by NPC Corporation. A sheet sealing material laminate 1 was produced. Then, using the produced front protective sheet sealing material laminate 1, the total light transmittance and moisture proof retention were measured by the above methods. The results are shown in Table 3.
  • “ETFE” means ETFE made by Asahi Glass and “BF” means Tech Barrier LX made by Mitsubishi Plastics.
  • Example 5 The weather-resistant layer, the flexible layer 2, the moisture-proof layer and the flexible layer 2 are laminated by vacuum lamination in the same manner as in Example 4 to produce the front protective sheet sealing material laminate 2, and the total light transmittance and moisture-proof retaining property are similarly obtained. Was measured. The results are shown in Table 3.
  • Example 6 The weather-resistant layer, the flexible layer 3, the moisture-proof layer, and the flexible layer 3 are laminated by vacuum lamination in the same manner as in Example 4 to produce the front protective sheet sealing material laminate 3 in the same manner. Was measured. The results are shown in Table 3.
  • Example 7 The weather-resistant layer, the flexible layer 9, the moisture-proof layer and the flexible layer 9 are laminated by vacuum lamination in the same manner as in Example 4 to produce the front protective sheet sealing material laminate 4, and the total light transmittance and moisture-proof retaining property are similarly obtained. Was measured. The results are shown in Table 3.
  • Comparative Example 6 A weather-resistant layer, a flexible layer 4, a moisture-proof layer, and a flexible layer 4 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminated product 5, and similarly, the total light transmittance and moisture-proof retaining property. Was measured. The results are shown in Table 3.
  • Comparative Example 7 A weather-resistant layer, a flexible layer 5, a moisture-proof layer, and a flexible layer 5 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminated product 6, and similarly, the total light transmittance and moisture-proof retaining property. Was measured. The results are shown in Table 3.
  • Comparative Example 8 A weather-resistant layer, a flexible layer 6, a moisture-proof layer, and a flexible layer 6 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminate 7 and similarly, the total light transmittance and moisture-proof retention was measured. The results are shown in Table 3.
  • Comparative Example 9 The weather-resistant layer, the flexible layer 7, the moisture-proof layer, and the flexible layer 7 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminate 8 and similarly, the total light transmittance and moisture-proof retention. Was measured. The results are shown in Table 3.
  • Comparative Example 10 A weather-resistant layer, a flexible layer 8, a moisture-proof layer, and a flexible layer 8 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminate 9 and similarly, the total light transmittance and moisture-proof retention property. Was measured. The results are shown in Table 3.
  • Comparative Example 11 The weather-resistant layer, the flexible layer 7, the moisture-proof layer, and the flexible layer 1 are laminated by vacuum lamination in the same manner as in Example 4 to produce the front protective sheet sealing material laminate 10, and the total light transmittance and moisture-proof retaining property are similarly obtained. Was measured. The results are shown in Table 3.
  • Comparative Example 12 A weather-resistant layer, a flexible layer 8, a moisture-proof layer, and a flexible layer 1 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminate 11, and similarly, the total light transmittance and moisture-proof retention. Was measured. The results are shown in Table 3.
  • Reference example 1 The weather-resistant layer, the flexible layer 1, the moisture-proof layer, and the flexible layer 7 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminate 12 and similarly, the total light transmittance and moisture-proof retention. Was measured. The results are shown in Table 3.
  • front protective sheet sealing material laminates 1 to 4 of the present invention were both excellent in moisture resistance and weather resistance and excellent in transparency.
  • the flexible layers 1 to 3 and 9 used in the front protective sheet sealing material laminate of the present invention have the flexibility, heat resistance and transparency necessary for protecting the moisture-proof layer.
  • the film had a sufficient thickness and a good balance. Therefore, the front protective sheet encapsulant laminates of Examples 4 to 7 produced using the flexible layers 1 to 3 and 9 have both high moisture resistance and weather resistance, and are not only excellent in transparency,
  • the moisture-proof layer can withstand long-term use under high-temperature / inclined conditions, and can be protected from impact from falling objects.
  • the flexible layers 4 and 8 are inferior in heat resistance, and when used under high temperature / tilting conditions, it has been revealed that the flexible layers 4 and 8 are displaced from the reference position or the sheet is melted.
  • the flexible layer cannot fulfill its role, and the moisture-proof layer is not sufficiently protected. That is, it is not preferable as a material for a solar cell member that is expected to be used under high temperature and inclined conditions. Further, it was shown that the flexible layers 5 to 7 were inferior in flexibility (storage modulus) and the moisture-proof layer was not sufficiently protected. Accordingly, even in the front protective sheet sealing material laminate manufactured using the flexible layers 5 to 7, the flexible layer cannot fulfill its role, and the moisture-proof layer is not sufficiently protected.

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Abstract

Provided are a front surface protective sheet for a solar cell and a front surface protective sheet-sealing material laminate for a solar cell, each of which comprises a resin layer having good balance between flexibility and heat resistance or transparency, thereby preventing deterioration in moisture prevention performance of the front surface protective sheet from a falling object or the like, while having transparency, high long-term moisture resistance and high long-term weather resistance at the same time. The front surface protective sheet for a solar cell and the front surface protective sheet-sealing material laminate for a solar cell are effective for weight reduction and durability improvement of a solar cell. Specifically disclosed are: a front surface protective sheet for a solar cell which is obtained by laminating a weather resistant layer (A) and a moisture prevention layer (B) with a flexible layer (C) being interposed therebetween, said flexible layer (C) containing an ethylene-α-olefin random copolymer (C-1) that has a crystal melting enthalpy of 0-70 J/g as determined by differential scanning calorimetry at a heating rate of 10˚C/minute and an ethylene-α-olefin block copolymer (C-2) that has a crystal melting peak temperature of 100˚C or more and a crystal melting enthalpy of 5-70 J/g as determined by differential scanning calorimetry at a heating rate of 10˚C/minute; and a front surface protective sheet-sealing material laminate for a solar cell, which is obtained by laminating a specific sealing material (D) on the front surface protective sheet for a solar cell.

Description

太陽電池用前面保護シート及びそれを用いて作製された太陽電池モジュールFront protective sheet for solar cell and solar cell module produced using the same
　本発明は、太陽電池用セルの前面保護部材として用いられる前面保護シート、及びこれと封止材の積層体に関し、特に、柔軟性と防湿性と耐候性を兼備する樹脂層よりなり、太陽電池の軽量化、耐久性の向上に有効な太陽電池用前面保護シート、これと透明性と耐熱性の向上に有効な封止材との積層体とした太陽電池用前面保護シート・封止材積層体、及びこの太陽電池用前面保護シートあるいは積層体を用いた軽量、高耐久性の太陽電池に関する。 The present invention relates to a front protective sheet used as a front protective member for a cell for solar cells, and a laminate of the same and a sealing material, and more particularly, a solar cell comprising a resin layer having flexibility, moisture resistance and weather resistance. Solar cell front protective sheet effective for weight reduction and durability improvement, and laminate of solar cell front protective sheet / encapsulant laminated with a sealing material effective for improving transparency and heat resistance The present invention relates to a lightweight and highly durable solar cell using the solar cell front protective sheet or laminate.
　近年、資源の有効利用や環境汚染の防止等の面から、太陽光を直接電気エネルギーに変換する太陽電池が注目され、開発が進められている。太陽電池は受光面側より前面保護シートと裏面保護シートとの間にエチレン－ 酢酸ビニル共重合体やポリエチレン、ポリプロピレンフィルムなどの封止膜により太陽電池用セルを封止した構成とされている。
　このような太陽電池は、通常、前面保護シート、封止膜 、発電素子、封止膜及び裏面保護シートをこの順で積層し、加熱溶融させることにより接着一体化することで製造される。太陽電池の前面保護シートとしては、紫外線に対する耐久性に優れることが要求されるが、加えて、湿気ないし水の透過による内部の導線や電極の発錆を防止するために、防湿性に優れることが極めて重要な要件となる。また封止材には、太陽電池素子を保護する為の柔軟性や耐衝撃性、太陽電池モジュールが発熱した際の耐熱性、太陽電池素子へ太陽光が効率的に届く為の透明性（全光線透過率など）、耐久性、寸法安定性、難燃性、水蒸気バリア性等が主に要求される。
　このため、従来は、表面側保護部材としてガラス板が用いられている。しかし、ガラス板は耐光性、防湿性に優れる反面、重量が重く、また、衝撃に弱く割れ易いという欠点がある。この問題に対して、たとえば特許文献１では前面保護シートに透明樹脂フィルムを用い、重さ及び衝撃による破損の問題を解決し、また前面保護シートに耐候性、防湿性が良好な樹脂フィルムを組み合わせることにより太陽電池の耐久性の向上に有効な太陽電池用前面保護シートが提案されている。
　しかしながら、特許文献１記載の太陽電池用前面保護シートにおいて、前面保護シートに接着剤を用いて耐候層と防湿層を張り合わせる場合，接着剤を厚くすることは生産性の観点から難しく，太陽電池受光面への落下物により防湿層が破損し防湿機能を劣下させてしまうことがあった。 In recent years, solar cells that directly convert sunlight into electric energy have attracted attention and are being developed from the viewpoint of effective use of resources and prevention of environmental pollution. A solar cell has a configuration in which solar cell cells are sealed between a front surface protective sheet and a back surface protective sheet from the light receiving surface side by a sealing film such as an ethylene-vinyl acetate copolymer, polyethylene, or polypropylene film.
Such a solar cell is usually manufactured by laminating a front protective sheet, a sealing film, a power generation element, a sealing film, and a back protective sheet in this order and bonding them together by heating and melting. As a front protective sheet for solar cells, it is required to have excellent durability against ultraviolet rays. In addition, in order to prevent rusting of internal conductors and electrodes due to moisture or water permeation, it is excellent in moisture resistance. Is an extremely important requirement. In addition, the sealing material has flexibility and impact resistance to protect the solar cell element, heat resistance when the solar cell module generates heat, and transparency to efficiently reach the solar cell element (all Light transmittance, etc.), durability, dimensional stability, flame retardancy, water vapor barrier properties, etc. are mainly required.
For this reason, conventionally, a glass plate is used as the surface-side protection member. However, the glass plate is excellent in light resistance and moisture resistance, but has a drawback that it is heavy and weak against impact and easily cracked. For example, in Patent Document 1, a transparent resin film is used for the front protective sheet to solve the problem of damage due to weight and impact, and the front protective sheet is combined with a resin film having good weather resistance and moisture resistance. Therefore, a solar cell front protective sheet effective for improving the durability of the solar cell has been proposed.
However, in the front protective sheet for solar cells described in Patent Document 1, when the weather resistant layer and the moisture-proof layer are bonded to the front protective sheet using an adhesive, it is difficult to increase the thickness of the adhesive from the viewpoint of productivity. In some cases, the moisture-proof layer is damaged by falling objects on the light-receiving surface, thereby deteriorating the moisture-proof function.
　一方、接着剤を用いず、前面保護シートに、太陽電子用封止材に一般に用いるエチレン－ 酢酸ビニル共重合体を耐候層と防湿層を張り合わせるフィルムとして使用し，封止材と組み合わせて太陽電池への落下物による防湿機能の劣下を防ぐ方法が提案されている(特許文献２)。
　しかしながら，エチレン－ 酢酸ビニル共重合体を使用する場合、通常、これに耐熱性を付与することを主な目的として有機過酸化物などの架橋剤を用いた架橋が行われるため，架橋にともなう表面外観悪化や防湿層の劣下が生じる。また、エチレン－酢酸ビニル共重合体には、長期間における使用に際して、エチレン－酢酸ビニル共重合体の加水分解等により発生する酢酸、架橋剤、架橋助剤などに起因して、前面保護シート内の樹脂や接着剤を劣下させ層内界面での剥離が発生する問題があった。また、封止材にもエチレン－ 酢酸ビニル共重合体を使用されるため，太陽電池を製造する真空ラミネーションにおいて，防湿層の上下において架橋収縮による応力が発生し，防湿層のバリア性を著しく低下させてしまうという問題もあった。
　また架橋を必要とせず、酢酸の発生がないα－オレフィン重合体からなる太陽電池封止材(特許文献３)や、少なくとも一種のポリオレフィン系共重合体と、少なくとも一種の結晶性ポリオレフィンからなるポリマーブレンドまたはポリマーアロイからなることを特徴とする太陽電池封止材（特許文献４）が開示されている。特に上記特許文献４には、具体的に、低融点のエチレン－ 酢酸ビニル共重合体と高融点のエチレン－酢酸ビニル共重合体とのポリマーブレンド（実施例１参照）、エチレン－メタクリル酸共重合体と汎用の結晶性ポリエチレンとのポリマーブレンド（実施例２参照）、エチレン－アクリル酸メチル共重合体と汎用の結晶性ポリプロピレンとのポリマーブレンド（実施例３参照）が開示されている。 On the other hand, without using an adhesive, the front protective sheet is made of an ethylene-vinyl acetate copolymer, which is generally used as a sealing material for solar electronics, as a film for laminating a weatherproof layer and a moisture-proof layer. A method for preventing deterioration of the moisture-proof function due to falling objects on the battery has been proposed (Patent Document 2).
However, when an ethylene-vinyl acetate copolymer is used, crosslinking is usually performed using a crosslinking agent such as an organic peroxide for the purpose of imparting heat resistance to the copolymer. Deterioration of appearance and deterioration of moisture-proof layer occur. In addition, the ethylene-vinyl acetate copolymer contains an acetic acid, a crosslinking agent, a crosslinking aid, etc. generated by hydrolysis of the ethylene-vinyl acetate copolymer during long-term use. There is a problem in that the resin and the adhesive are deteriorated and peeling at the interface in the layer occurs. Also, since ethylene-vinyl acetate copolymer is used for the sealing material, stress due to cross-linking shrinkage is generated above and below the moisture-proof layer in vacuum lamination for manufacturing solar cells, and the barrier property of the moisture-proof layer is significantly reduced. There was also a problem of letting it go.
Further, a solar cell encapsulant made of an α-olefin polymer that does not require crosslinking and does not generate acetic acid (Patent Document 3), or a polymer made of at least one polyolefin copolymer and at least one crystalline polyolefin A solar cell encapsulating material (Patent Document 4) comprising a blend or a polymer alloy is disclosed. In particular, the above Patent Document 4 specifically describes a polymer blend of a low melting point ethylene-vinyl acetate copolymer and a high melting point ethylene-vinyl acetate copolymer (see Example 1), ethylene-methacrylic acid copolymer. Polymer blends of coalesced and general purpose crystalline polyethylene (see Example 2) and polymer blends of ethylene-methyl acrylate copolymer and general purpose crystalline polypropylene (see Example 3) are disclosed.
　しかし、上記特許文献３で具体的に用いられているプロピレンを主成分とする重合体からなる樹脂組成物では、透明性が不十分であり（全光線透過率：８３．２％（実施例参照））、前面保護シート内の張り合わせフィルムとして使用した場合，前面保護シート全体の光線透過率が低下し太陽電池の発電効率が低下する。また、特許文献４で用いられている各ポリマーブレンドは、必ずしも透明性に優れたものではなく、柔軟性と耐熱性および透明性とのバランス化においては未だ問題があった。更に、このような重合体を前面保護シート及び封止材の両方に使用することは太陽電池の性能に重大な影響を与える光線透過率の著しい劣下を招くことになる。
　尚、上記特許文献３、４のいずれにおいても、前面保護シートと封止材の組み合わせにおいて，透明性，全光線透過率の低下による太陽電池の性能低下を防止しながら，前面保護シートにおける防湿層の劣化を防ぎ、これにより長期の高い防湿性と耐候性を兼備し、かつ太陽電池の耐久性の向上を図ると言う着眼はない。このように、従来の太陽電池用前面保護シート、及びこれと封止材の組み合わせに関する技術において、透明性，全光線透過率の低下による太陽電池の性能低下を防止しながら，前面保護シートにおける防湿層層の劣化に対する有用な解決手段は提案されてなかった。 However, the resin composition comprising a polymer mainly composed of propylene specifically used in Patent Document 3 has insufficient transparency (total light transmittance: 83.2% (see Examples). ))) When used as a laminated film in the front protective sheet, the light transmittance of the entire front protective sheet is lowered, and the power generation efficiency of the solar cell is lowered. Further, each polymer blend used in Patent Document 4 is not necessarily excellent in transparency, and there is still a problem in balancing the flexibility, heat resistance and transparency. Furthermore, the use of such a polymer for both the front protective sheet and the encapsulant leads to a significant deterioration in light transmittance, which seriously affects the performance of the solar cell.
In any of the above Patent Documents 3 and 4, in the combination of the front protective sheet and the sealing material, the moisture-proof layer in the front protective sheet is prevented while preventing deterioration in the performance of the solar cell due to the decrease in transparency and total light transmittance. There is no focus on preventing deterioration of the solar cell, thereby combining long-term high moisture resistance and weather resistance, and improving the durability of the solar cell. Thus, in the conventional technology for the front protective sheet for solar cells and the combination of this and the sealing material, moisture resistance in the front protective sheet is prevented while preventing the deterioration of the performance of the solar cell due to the decrease in transparency and total light transmittance. No useful solution for layer degradation has been proposed.
特許第３９７８９１１号公報Japanese Patent No. 3978911 特許第３９７８９１２号公報Japanese Patent No. 3978912 特開２００６－２１０９０５号公報JP 2006-210905 A 特開２００１－３３２７５０号公報JP 2001-332750 A
　すなわち、本発明の課題は、太陽電池用セルの透明保護部材として用いられる保護シートにおいて、前記従来の問題を解決し、該シートの一部を構成する防湿性能を有する樹脂層の劣化を防ぐために、柔軟性と耐熱性および透明性との良好なバランスが図られた樹脂層を有することによって、落下物などによる前面保護シートの防湿性能の劣下を防ぎ、透明性及び長期の高い防湿性と耐候性を兼備し、かつ太陽電池の軽量化、耐久性の向上に有効な太陽電池用前面保護シートを提供すること、及びこれと透明性，耐熱性に優れた封止材との組み合わせにより全光線透過率の低下を防止し太陽電池の性能低下を同時に防止し，太陽電池の軽量化、耐久性の向上に有効な太陽電池用前面保護シート・封止材積層体を提供することにある。
　また、本発明の課題は、この太陽電池用前面保護シートあるいは太陽電池用前面保護シート・封止材積層体を用いた、軽量、高耐久性の太陽電池モジュール及び太陽電池を提供することにある。 That is, an object of the present invention is to solve the above-mentioned conventional problems in a protective sheet used as a transparent protective member for a solar cell, and to prevent deterioration of a resin layer having a moisture-proof performance constituting a part of the sheet By having a resin layer with a good balance between flexibility, heat resistance and transparency, it prevents deterioration of the moisture resistance of the front protective sheet due to falling objects, etc., and transparency and long-term high moisture resistance Providing a front protective sheet for solar cells that has both weather resistance and is effective in reducing the weight and durability of solar cells, and combining this with a sealing material with excellent transparency and heat resistance. An object of the present invention is to provide a solar cell front protective sheet / sealing material laminate that is effective in preventing a decrease in light transmittance and simultaneously preventing a decrease in the performance of a solar cell and reducing the weight and durability of the solar cell.
Another object of the present invention is to provide a lightweight and highly durable solar cell module and solar cell using the solar cell front protective sheet or solar cell front protective sheet / sealing material laminate. .
　本発明者らは、鋭意検討を重ねた結果、特定の熱特性を有するエチレン－α－オレフィンランダム共重合体と特定の熱特性を有するエチレン－α－オレフィンブロック共重合体を含有する樹脂層を太陽電池用前面保護シート、あるいは太陽電池用前面保護シート・封止材積層体に用いることにより、柔軟性、耐熱性および透明性を同時に満足できることを見出し、本発明を完成するに至った。
　すなわち、本発明は、
　耐候層（Ａ）と防湿層（Ｂ）とを、下記(１)の条件を満足するエチレン－α－オレフィンランダム共重合体（Ｃ－１）と下記(２)の条件を満足するエチレン－α－オレフィンブロック共重合体（Ｃ－２）とを含有する柔軟層（Ｃ）を介して積層してなることを特徴とする太陽電池用前面保護シート、及び前記太陽電池用前面保護シートに、下記(１)の条件を満足するエチレン－α－オレフィンランダム共重合体（Ｄー１）と下記(２)の条件を満足するエチレン－α－オレフィンブロック共重合体（Ｄー２）とを含有する封止材（Ｄ）を積層してなる太陽電池用前面保護シート・封止材積層体に関する。
　　（１）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解熱量が０～７０Ｊ／ｇ
　　（２）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解ピーク温度が１００℃以上であり、かつ、結晶融解熱量が５～７０Ｊ／ｇ As a result of intensive studies, the present inventors have obtained a resin layer containing an ethylene-α-olefin random copolymer having specific thermal characteristics and an ethylene-α-olefin block copolymer having specific thermal characteristics. By using the solar cell front protective sheet or the solar cell front protective sheet / sealing material laminate, it has been found that flexibility, heat resistance and transparency can be satisfied at the same time, and the present invention has been completed.
That is, the present invention
The weather-resistant layer (A) and the moisture-proof layer (B) are divided into an ethylene-α-olefin random copolymer (C-1) that satisfies the following condition (1) and an ethylene-α that satisfies the following condition (2): -A front protective sheet for solar cells, which is laminated through a flexible layer (C) containing an olefin block copolymer (C-2), and the front protective sheet for solar cells, An ethylene-α-olefin random copolymer (D-1) satisfying the condition (1) and an ethylene-α-olefin block copolymer (D-2) satisfying the condition (2) below are contained. The present invention relates to a solar cell front protective sheet / sealing material laminate formed by laminating a sealing material (D).
(1) The heat of crystal fusion measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 70 J / g.
(2) The crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or more, and the crystal melting heat amount is 5 to 70 J / g.
　また、本発明は、前記本発明の太陽電池用前面保護シート、あるいは太陽電池用前面保護シート・封止材積層体を用いて作製された太陽電池モジュール及び太陽電池に関する。 The present invention also relates to a solar cell module and a solar cell produced using the solar cell front protective sheet or solar cell front protective sheet / sealing material laminate of the present invention.
　本発明によれば、柔軟性と耐熱性および透明性とのバランスが図られた特定の構成の樹脂層を有することにより、落下物などによる防湿層の劣化が引き起こす前面シートの防湿性能の劣下を防ぐことができ、透明性及び長期の高防湿性と耐候性を兼備し、かつ太陽電池の軽量化、耐久性の向上に有効な太陽電池用前面保護シート、及び太陽電池用前面保護シート・封止材積層体を提供することができ、また、この太陽電池用前面保護シートまたは太陽電池用前面保護シート・封止材積層体を用いた、軽量、高耐久性の太陽電池モジュールならびに太陽電池を提供することができる。 According to the present invention, by having a resin layer with a specific configuration in which a balance between flexibility, heat resistance, and transparency is achieved, the moisture resistance of the front sheet deteriorates due to deterioration of the moisture barrier due to falling objects or the like. A front protection sheet for solar cells, which has both transparency and long-term high moisture resistance and weather resistance, and is effective in reducing the weight and durability of solar cells, and the front protection sheet for solar cells A sealing material laminate can be provided, and a lightweight, highly durable solar cell module and a solar cell using the solar cell front protective sheet or solar cell front protective sheet / sealing material laminate Can be provided.
本発明の太陽電池用前面保護シートの実施の形態の一例を示す概略断面図であるIt is a schematic sectional drawing which shows an example of embodiment of the front protective sheet for solar cells of this invention. 本発明の太陽電池用前面保護シート・封止材積層体の実施の形態の一例を示す概略断面図であるIt is a schematic sectional drawing which shows an example of embodiment of the front surface protection sheet for solar cells of this invention, and a sealing material laminated body. 本発明の太陽電池モジュールの一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the solar cell module of this invention.
　以下、本発明を更に詳細に説明する。なお、本発明においては、「層」と称する場合は、「フィルム」及び「シート」を含むことがあるものとする。
＜耐候層（Ａ）＞
　本発明における耐候層（Ａ）とは可撓性に富み、耐熱性、防湿性、紫外線耐久性に優れ、好ましくは高透明である層をいい、太陽電池前面保護シートと表面外観の維持を目的として用いられる。
　耐候層の耐候性は、ＪＩＳ　Ｋ７３５０に準じてなされるサンシャインウェザーメーターによる耐候性試験において、力学物性や全光線透過率の低下が少ないものが好ましく、５０００時間経過後の力学物性や全光線透過率の低下がないものがより好ましく、１００００時間経過後の力学物性や全光線透過率の低下がないものが特に好ましい。
　耐候層（Ａ）の材料としては、例えば、ポリテトラフルオロエチレン（ＰＴＦＥ）、４－フッ化エチレン－パークロロアルコキシ共重合体（ＰＦＡ）、４－フッ化エチレン－６－フッ化プロピレン共重合体（ＦＥＰ）、２－エチレン－４－フッ化エチレン共重合体（ＥＴＦＥ）、ポリ３－フッ化塩化エチレン（ＰＣＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）及びポリフッ化ビニル（ＰＶＦ）等のフッ素樹脂フィルム、或いは、アクリル、ポリカーボネート、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）等の樹脂に紫外線吸収剤を練り込んだ樹脂組成物を成膜したものが好ましく用いられ、長期耐久性と高光線透過率の観点から、２－エチレン－４－フッ化エチレン共重合体（ＥＴＦＥ）、４－フッ化エチレン－６－フッ化プロピレン共重合体（ＦＥＰ）がより好ましく用いられる。なお、上記紫外線吸収剤としては、柔軟層に含有されうる後述の紫外線吸収剤と同様のものが使用できる。上記樹脂は、１種で用いることもできるが２種以上組合せて使用することもできる。 Hereinafter, the present invention will be described in more detail. In the present invention, the term “layer” may include “film” and “sheet”.
<Weather-resistant layer (A)>
The weather-resistant layer (A) in the present invention is a layer that is rich in flexibility, excellent in heat resistance, moisture resistance, and UV durability, and preferably highly transparent, and aims to maintain the solar cell front protective sheet and the surface appearance. Used as
The weather resistance of the weather resistant layer is preferably such that there is little decrease in mechanical properties and total light transmittance in a weather resistance test conducted according to JIS K7350, and mechanical properties and total light transmittance after 5000 hours have passed. Are preferable, and those having no decrease in mechanical properties and total light transmittance after 10000 hours are particularly preferable.
Examples of the material for the weathering layer (A) include polytetrafluoroethylene (PTFE), 4-fluorinated ethylene-perchloroalkoxy copolymer (PFA), and 4-fluorinated ethylene-6-fluorinated propylene copolymer. Fluoropolymer films such as (FEP), 2-ethylene-4-fluoroethylene copolymer (ETFE), poly-3-fluoroethylene chloride (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF), Alternatively, a film obtained by forming a resin composition in which an ultraviolet absorber is kneaded into a resin such as acrylic, polycarbonate, polyethylene terephthalate (PET), or polyethylene naphthalate (PEN) is preferably used, and long-term durability and high light transmittance are used. In view of the above, 2-ethylene-4-fluoroethylene copolymer (ETFE), 4-fluoroethylene Ren-6-fluorinated propylene copolymer (FEP) is more preferably used. In addition, as said ultraviolet absorber, the thing similar to the below-mentioned ultraviolet absorber which can be contained in a flexible layer can be used. Although the said resin can also be used by 1 type, it can also be used in combination of 2 or more type.
　上記耐候層（Ａ）の厚さは、一般に２０～２００μｍ程度であり、フィルムとしての取り扱いやすさとコストの点から３０～１２０μｍが好ましく、４０～８０μｍがより好ましい。 The thickness of the weather resistant layer (A) is generally about 20 to 200 μm, preferably 30 to 120 μm, more preferably 40 to 80 μm from the viewpoint of ease of handling as a film and cost.
＜防湿層（Ｂ）＞
　本発明における防湿層（Ｂ）とは、湿気、水の透過による内部の導線、電極の発錆等を防止するために用いられ、好ましくは高透明であり、防湿性に優れた樹脂層であれば特に制限はないが、基材層の少なくとも一方の面に無機酸化物のコーティング膜を少なくとも1層有するものが好ましく用いられる。
　上記基材層としては、熱可塑性高分子フィルムが好ましく、その材料としては、通常の包装材料に使用しうる樹脂であれば特に制限なく用いることができる。具体的には、エチレン、プロピレン、ブテン等の単独重合体または共重合体などのポリオレフィン、環状ポリオレフィン等の非晶質ポリオレフィン、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）等のポリエステル、ナイロン６、ナイロン６６、ナイロン１２、共重合ナイロン等のポリアミド、エチレン－酢酸ビニル共重合体部分加水分解物（ＥＶＯＨ）、ポリイミド、ポリエーテルイミド、ポリサルホン、ポリエーテルサルホン、ポリエーテルエーテルケトン、ポリカーボネート、ポリビニルブチラール、ポリアリレート、フッ素樹脂、アクリレート樹脂、生分解性樹脂などが挙げられる。これらの中では、フィルム物性、コストなどの点から、ポリエステル、ポリアミド、ポリオレフィンが好ましい。中でも、フィルム物性の点から、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）が特に好ましい。 <Dampproof layer (B)>
The moisture-proof layer (B) in the present invention is a resin layer that is used to prevent moisture, internal conductors due to permeation of water, rusting of electrodes, and the like, and is preferably a resin layer that is highly transparent and excellent in moisture resistance. Although there is no particular limitation, those having at least one inorganic oxide coating film on at least one surface of the base material layer are preferably used.
The base material layer is preferably a thermoplastic polymer film, and any material can be used without particular limitation as long as it is a resin that can be used for ordinary packaging materials. Specifically, polyolefins such as homopolymers or copolymers such as ethylene, propylene and butene, amorphous polyolefins such as cyclic polyolefins, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), nylon 6 , Nylon 66, nylon 12, polyamide such as copolymer nylon, ethylene-vinyl acetate copolymer partial hydrolyzate (EVOH), polyimide, polyetherimide, polysulfone, polyethersulfone, polyetheretherketone, polycarbonate, polyvinyl Examples include butyral, polyarylate, fluororesin, acrylate resin, and biodegradable resin. Among these, polyesters, polyamides, and polyolefins are preferable from the viewpoints of film properties and cost. Among these, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are particularly preferable from the viewpoint of film properties.
　また、上記基材層は、公知の添加剤、例えば、帯電防止剤、光線遮断剤、紫外線吸収剤、可塑剤、滑剤、フィラー、着色剤、安定剤、潤滑剤、架橋剤、ブロッキング防止剤、酸化防止剤等を含有することができる。
　上記基材層としての熱可塑性高分子フィルムは、上記の原料を用いて成形してなるものであるが、基材として用いる際は、未延伸であってもよいし延伸したものであってもよい。また、他のプラスチック基材と積層されていてもよい。 In addition, the base material layer is a known additive such as an antistatic agent, a light blocking agent, an ultraviolet absorber, a plasticizer, a lubricant, a filler, a colorant, a stabilizer, a lubricant, a crosslinking agent, an antiblocking agent, An antioxidant etc. can be contained.
The thermoplastic polymer film as the base material layer is formed by using the above raw materials, but when used as a base material, it may be unstretched or stretched. Good. Moreover, you may laminate | stack with the other plastic base material.
　かかる基材層は、従来公知の方法により製造することができ、例えば、原料樹脂を押出機により溶融し、環状ダイやＴダイにより押出して、急冷することにより実質的に無定型で配向していない未延伸フィルムを製造することができる。また、多層ダイを用いることにより、１種の樹脂からなる単層フィルム、１種の樹脂からなる多層フィルム、多種の樹脂からなる多層フィルム等を製造することができる。 Such a base material layer can be produced by a conventionally known method. For example, the raw material resin is melted by an extruder, extruded by an annular die or a T die, and rapidly cooled to be oriented substantially amorphously. No unstretched film can be produced. Further, by using a multilayer die, it is possible to produce a single layer film made of one kind of resin, a multilayer film made of one kind of resin, a multilayer film made of various kinds of resins, and the like.
　この未延伸フィルムを一軸延伸、テンター式逐次二軸延伸、テンター式同時二軸延伸、チューブラー式同時二軸延伸などの公知の方法により、フィルムの流れ（縦軸）方向又はフィルムの流れ方向とそれに直角な（横軸）方向に延伸することにより、少なくとも一軸方向に延伸したフィルムを製造することができる。延伸倍率は任意に設定できるが、１５０℃熱収縮率が、０．０１～５％、更には０．０１～２％であることが好ましい。中でもフィルム物性の点から、二軸延伸ポリエチレンナフタレートフィルムや、ポリエチレンテレフタレート及び／又はポリエチレンナフタレートと他のプラスチックの共押出二軸延伸フィルムが好ましい。 The unstretched film is subjected to a known method such as uniaxial stretching, tenter sequential biaxial stretching, tenter simultaneous biaxial stretching, tubular simultaneous biaxial stretching, or the like. A film stretched in at least a uniaxial direction can be produced by stretching in a direction (horizontal axis) perpendicular thereto. The draw ratio can be arbitrarily set, but the heat shrinkage at 150 ° C. is preferably 0.01 to 5%, more preferably 0.01 to 2%. Among these, from the viewpoint of film properties, a biaxially stretched polyethylene naphthalate film, a polyethylene terephthalate and / or a coextruded biaxially stretched film of polyethylene naphthalate and other plastics are preferable.
　なお、上記基材層には、無機薄膜との密着性向上のため、アンカーコート剤を塗布することが好ましい。アンカーコート剤としては、溶剤性又は水性のポリエステル樹脂、イソシアネート樹脂、ウレタン樹脂、アクリル樹脂、ビニル変性樹脂、ビニルアルコール樹脂、ビニルブチラール樹脂、エチレンビニルアルコール樹脂、ニトロセルロース樹脂、オキサゾリン基含有樹脂、カルボジイミド基含有樹脂、メチレン基含有樹脂、エポキシ基含有樹脂、変性スチレン樹脂、変性シリコン樹脂及びアルキルチタネート等を単独、あるいは２種以上組み合わせて使用することができる。また、シラン系カップリング剤、チタン系カップリング剤、光線遮断剤、紫外線吸収剤、安定剤、潤滑剤、ブロッキング防止剤、酸化防止剤等を含有したり、それらを上記樹脂と共重合させたものを使用することができる。 In addition, it is preferable to apply an anchor coating agent to the base material layer in order to improve adhesion with the inorganic thin film. Examples of anchor coating agents include solvent-based or water-soluble polyester resins, isocyanate resins, urethane resins, acrylic resins, vinyl-modified resins, vinyl alcohol resins, vinyl butyral resins, ethylene vinyl alcohol resins, nitrocellulose resins, oxazoline group-containing resins, carbodiimides. A group-containing resin, a methylene group-containing resin, an epoxy group-containing resin, a modified styrene resin, a modified silicon resin, an alkyl titanate, or the like can be used alone or in combination of two or more. Also contains silane coupling agents, titanium coupling agents, light blocking agents, ultraviolet absorbers, stabilizers, lubricants, antiblocking agents, antioxidants, etc., or they are copolymerized with the above resins Things can be used.
　アンカーコート層の形成方法としては、公知のコーティング方法が適宜採択される。例えば、リバースロールコーター、グラビアコーター、ロッドコーター、エアドクタコーター、スプレイあるいは刷毛を用いたコーティング方法等の方法がいずれも使用できる。また、蒸着層を樹脂液に浸漬して行ってもよい。塗布後は、８０～２００℃程度の温度での熱風乾燥、熱ロール乾燥などの加熱乾燥や、赤外線乾燥などの公知の乾燥方法を用いて溶媒を蒸発させることができる。また、耐水性、耐久性を高めるために、電子線照射による架橋処理を行う事もできる。また、アンカーコート層の形成は、基材層の製造ラインの途中で行う方法（インライン）でも、基材層製造後に行う（オフライン）方法でも良い。 As a method for forming the anchor coat layer, a known coating method is appropriately adopted. For example, any method such as a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, a spray or a coating method using a brush can be used. Alternatively, the vapor deposition layer may be immersed in a resin solution. After coating, the solvent can be evaporated using a known drying method such as hot air drying or hot roll drying at a temperature of about 80 to 200 ° C. or infrared drying. Moreover, in order to improve water resistance and durability, the crosslinking process by electron beam irradiation can also be performed. Further, the formation of the anchor coat layer may be a method performed in the middle of the base material layer production line (in-line) or a method performed after the base material layer is manufactured (off-line).
　防湿層としては、該基材層にアルミニウム等の金属のコーティング膜を形成したものも知られているが、アルミニウム等の金属では、太陽電池に適用した場合、電流がリークする等の恐れがあるため、シリカ・アルミナ等の無機酸化物のコーティング膜が好ましく用いられる。 As a moisture-proof layer, a substrate in which a coating film of a metal such as aluminum is formed on the base material layer is known. However, when a metal such as aluminum is applied to a solar cell, current may leak. Therefore, an inorganic oxide coating film such as silica / alumina is preferably used.
　上記無機酸化物コーティング膜の形成方法としては、蒸着法、コーティング法などの方法がいずれも使用できるが、ガスバリア性の高い均一な薄膜が得られるという点で蒸着法が好ましい。この蒸着法には、物理気相蒸着（ＰＶＤ）、あるいは化学気相蒸着（ＣＶＤ）などの方法が含まれる。物理気相蒸着法には、真空蒸着、イオンプレーティング、スパッタリングなどが挙げられ、化学気相蒸着法には、プラズマを利用したプラズマＣＶＤ、加熱触媒体を用いて材料ガスを接触熱分解する触媒化学気相成長法（Ｃａｔ－ＣＶＤ）等が挙げられる。 As the method for forming the inorganic oxide coating film, any of a vapor deposition method and a coating method can be used, but a vapor deposition method is preferred in that a uniform thin film having a high gas barrier property can be obtained. This vapor deposition method includes methods such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). Examples of physical vapor deposition include vacuum deposition, ion plating, and sputtering, and chemical vapor deposition includes plasma CVD using plasma and a catalyst that thermally decomposes a material gas using a heated catalyst body. Examples include chemical vapor deposition (Cat-CVD).
　無機酸化物コーティング膜を構成する無機物質としては、珪素、アルミニウム、マグネシウム、亜鉛、錫、ニッケル、チタン、水素化炭素等、あるいはこれらの酸化物、炭化物、窒化物またはそれらの混合物が挙げられるが、好ましくは酸化珪素、酸化アルミニウム、水素化炭素を主体としたダイアモンドライクカーボンである。特に、酸化珪素、窒化珪素、酸化窒化珪素、酸化アルミニウムは、高いガスバリア性が安定に維持できる点で好ましい。 Examples of the inorganic substance constituting the inorganic oxide coating film include silicon, aluminum, magnesium, zinc, tin, nickel, titanium, hydrogenated carbon, and the like, or oxides, carbides, nitrides, or mixtures thereof. Of these, diamond like carbon mainly composed of silicon oxide, aluminum oxide, and hydrogenated carbon is preferable. In particular, silicon oxide, silicon nitride, silicon oxynitride, and aluminum oxide are preferable in that high gas barrier properties can be stably maintained.
　上記コーティング膜の厚さは、安定な防湿性能の発現の点から、４０～１０００ｎｍであることが好ましく、８０～８００ｎｍがより好ましく、１６０～６００ｎｍが更に好ましい。また、上記基材層の厚さは、一般に５～１００μｍ程度であり、生産性や取り扱いやすさの点から８～５０μｍが好ましく、１２～２５μｍが更に好ましい。従って、上記防湿層（Ａ）の厚さは、一般に６～１００μｍ程度であり、生産性や取り扱いやすさの点から９～５０μｍが好ましく、１２～２５μｍが更に好ましい。 The thickness of the coating film is preferably 40 to 1000 nm, more preferably 80 to 800 nm, and still more preferably 160 to 600 nm from the viewpoint of stable moistureproof performance. The thickness of the base material layer is generally about 5 to 100 μm, preferably 8 to 50 μm, more preferably 12 to 25 μm from the viewpoint of productivity and ease of handling. Accordingly, the thickness of the moisture-proof layer (A) is generally about 6 to 100 μm, preferably 9 to 50 μm, more preferably 12 to 25 μm from the viewpoint of productivity and ease of handling.
＜柔軟層（Ｃ）＞
　本発明における柔軟層（Ｃ）とは、前記耐候層（Ａ）と防湿層（Ｂ）との間に配置され使用されるものである。柔軟層（Ｃ）としては、具体的には、高透明で可撓性に富み、耐熱性、加水分解性に優れることから、エチレン－α－オレフィン共重合体からなる樹脂層が用いられ、さらに、特定の熱特性を有するエチレン－α－オレフィンランダム共重合体と特定の熱特性を有するエチレン－α－オレフィンブロック共重合体を含有する樹脂組成物を使用することが高光線透過率，耐熱性，柔軟性の発現の観点から必要となる。 <Flexible layer (C)>
The flexible layer (C) in the present invention is used between the weather-resistant layer (A) and the moisture-proof layer (B). As the flexible layer (C), specifically, a resin layer made of an ethylene-α-olefin copolymer is used because it is highly transparent, rich in flexibility, and excellent in heat resistance and hydrolysis. It is possible to use a resin composition containing an ethylene-α-olefin random copolymer having specific thermal characteristics and an ethylene-α-olefin block copolymer having specific thermal characteristics. This is necessary from the viewpoint of expressing flexibility.
　ここで特定の熱特性を有するエチレン－α－オレフィンランダム共重合体とは下記（１）の条件を満足するエチレン－α－オレフィンランダム共重合体（Ｃ－１）であり、特定の熱特性を有するエチレン－α－オレフィンブロック共重合体とは下記（２）の条件を満足するエチレン－α－オレフィンブロック共重合体（Ｃ－２）である。
　　（１）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解熱量が０～７０Ｊ／ｇ
　　（２）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解ピーク温度が１００℃以上であり、かつ、結晶融解熱量が５～７０Ｊ／ｇ Here, the ethylene-α-olefin random copolymer having specific thermal characteristics is an ethylene-α-olefin random copolymer (C-1) that satisfies the following condition (1), and has specific thermal characteristics. The ethylene-α-olefin block copolymer possessed is an ethylene-α-olefin block copolymer (C-2) that satisfies the following condition (2).
(1) The heat of crystal fusion measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 70 J / g.
(2) The crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or more, and the crystal melting heat amount is 5 to 70 J / g.
　太陽電池用前面保護シートの耐熱性は柔軟層（Ｃ）を構成するエチレン－α－オレフィンランダム共重合体（Ｃ－１）の諸特性（結晶融解ピーク温度、結晶融解熱量、ＭＦＲ、分子量など）およびエチレン－α－オレフィンブロック共重合体（Ｃ－２）の諸特性（結晶融解ピーク温度、結晶融解熱量、ＭＦＲ、分子量など）により影響されるが、とくに、エチレン－α－オレフィンブロック共重合体（Ｃ－２）の結晶融解ピーク温度が強く影響する。 The heat resistance of the front protective sheet for solar cells is the characteristics of the ethylene-α-olefin random copolymer (C-1) constituting the flexible layer (C) (crystal melting peak temperature, crystal melting heat, MFR, molecular weight, etc.) And ethylene-α-olefin block copolymer (C-2), which are affected by various properties (crystal melting peak temperature, crystal melting heat, MFR, molecular weight, etc.), especially ethylene-α-olefin block copolymer The crystal melting peak temperature of (C-2) is strongly affected.
　一般に、太陽電池モジュールは発電時の発熱や太陽光の輻射熱などで、その温度が８５～９０℃程度まで昇温するが、柔軟層（Ｃ）におけるエチレン－α－オレフィンブロック共重合体（Ｃ－２）の結晶融解ピーク温度が１００℃以上であれば、太陽電池用前面保護シートの耐熱性を確保することが出来る。一方、エチレン－α－オレフィンブロック共重合体（Ｃ－２）の結晶融解ピーク温度の上限温度が１４５℃であれば、太陽電池素子の封止工程であまり高温にすることなく封止することができるため好ましい。また柔軟層（Ｃ）におけるエチレン－α－オレフィンランダム共重合体（Ｃ－１）及びエチレン－α－オレフィンブロック共重合体（Ｃ－２）の各々の結晶融解熱量が規定の範囲内であれば、前面保護シートの柔軟性や透明性（全光線透過率）などが確保され、また、原料ペレットのブロッキングなどの不具合も起こり難いため好ましい。 In general, the temperature of a solar cell module rises to about 85 to 90 ° C. due to heat generated during power generation or radiant heat of sunlight, but the ethylene-α-olefin block copolymer (C— If the crystal melting peak temperature of 2) is 100 ° C. or higher, the heat resistance of the front protective sheet for solar cells can be ensured. On the other hand, if the upper limit temperature of the crystal melting peak temperature of the ethylene-α-olefin block copolymer (C-2) is 145 ° C., it can be sealed without excessively high temperature in the sealing step of the solar cell element. This is preferable because it is possible. If the heat of fusion of each of the ethylene-α-olefin random copolymer (C-1) and the ethylene-α-olefin block copolymer (C-2) in the flexible layer (C) is within the specified range, In addition, flexibility and transparency (total light transmittance) of the front protective sheet are ensured, and problems such as blocking of raw material pellets are less likely to occur.
　本発明における柔軟層（Ｃ）を構成するエチレン－α－オレフィンランダム共重合体（Ｃ－１）及びエチレン－α－オレフィンブロック共重合体（Ｃ－２）の各々に用いられるα－オレフィンの種類は、同一であってもよいし、異なっていてもよいが、本発明においては、同一である方が、混合した際の相溶性や前面保護シートの透明性、すなわち、太陽電池の光電変換効率が向上するため好ましい。
　次に、柔軟層（Ｃ）におけるこれらの共重合体の混合（含有）質量比は、特に制限されるものではないが、好ましくは（Ｃ－１）／（Ｃ－２）＝９９～５０／１～５０、より好ましくは、９８～６０／２～４０、さらに好ましくは、９７～７０／３～３０である。但し、（Ｃ－１）と（Ｃ－２）の合計を１００質量部とする。ここで、混合（含有）質量比が上記範囲内であれば、柔軟性、耐熱性、透明性等のバランスに優れた柔軟層（Ｃ）が得られやすいため好ましい。 Types of α-olefins used in each of the ethylene-α-olefin random copolymer (C-1) and the ethylene-α-olefin block copolymer (C-2) constituting the flexible layer (C) in the present invention May be the same or different, but in the present invention, the same is the compatibility when mixed and the transparency of the front protective sheet, that is, the photoelectric conversion efficiency of the solar cell. Is preferable.
Next, the mixing (containing) mass ratio of these copolymers in the flexible layer (C) is not particularly limited, but is preferably (C-1) / (C-2) = 99 to 50 / 1 to 50, more preferably 98 to 60/2 to 40, and still more preferably 97 to 70/3 to 30. However, the total of (C-1) and (C-2) is 100 parts by mass. Here, it is preferable if the mixing (containing) mass ratio is in the above range because a flexible layer (C) having an excellent balance of flexibility, heat resistance, transparency and the like can be easily obtained.
　本発明における柔軟層（Ｃ）の柔軟性は、適用される太陽電池の形状や厚み、設置場所などを考慮して適宜調整すれば良いが、例えば、動的粘弾性測定における振動周波数１０Ｈｚ、温度２０℃の貯蔵弾性率（Ｅ´）が１～２０００ＭＰａであることが好ましい。太陽電池素子の保護の観点からは貯蔵弾性率（Ｅ´）は、より低い方が好ましいが、シート形状などで本発明の柔軟層（Ｃ）を採取した場合のハンドリング性やシート表面同士のブロッキング防止などを考慮すると、３～１０００ＭＰａであることがより好ましく、５～５００ＭＰａであることがさらに好ましく、１０～１００ＭＰａであることが特に好ましい。 The flexibility of the flexible layer (C) in the present invention may be appropriately adjusted in consideration of the shape, thickness, installation location, etc. of the applied solar cell. For example, the vibration frequency in dynamic viscoelasticity measurement is 10 Hz, temperature The storage elastic modulus (E ′) at 20 ° C. is preferably 1 to 2000 MPa. From the viewpoint of protection of the solar cell element, the storage elastic modulus (E ′) is preferably lower. However, handling properties and blocking between the sheet surfaces when the flexible layer (C) of the present invention is collected in a sheet shape or the like. In view of prevention and the like, the pressure is more preferably 3 to 1000 MPa, further preferably 5 to 500 MPa, and particularly preferably 10 to 100 MPa.
　本発明における柔軟層（Ｃ）の耐熱性は、エチレン－α－オレフィンランダム共重合体（Ｃ－１）の諸特性（結晶融解ピーク温度、結晶融解熱量、ＭＦＲ、分子量など）およびエチレン－α－オレフィンブロック共重合体（Ｃ－２）の諸特性（結晶融解ピーク温度、結晶融解熱量、ＭＦＲ、分子量など）により影響されるが、とくに、エチレン－α－オレフィンブロック共重合体（Ｃ－２）の結晶融解ピーク温度が強く影響する。
　上記の通り、柔軟層（Ｃ）におけるエチレン－α－オレフィンブロック共重合体（Ｃ－２）の結晶融解ピーク温度が１００℃以上であれば、本発明における柔軟層（Ｃ）の耐熱性を確保することが出来る。そして、前面保護シートは柔軟層（Ｃ）の耐熱性と弾性率が部材を構成する層において最も低いことから，前面保護シートの耐熱性については柔軟層（Ｃ）がその性能を決定する。
　本発明においては、柔軟層（Ｃ）の耐熱性は、厚み３ｍｍの白板ガラス（サイズ；縦７５ｍｍ、横２５ｍｍ）と厚み５ｍｍのアルミ板（サイズ；縦１２０ｍｍ、横６０ｍｍ）の間に厚みが０．５ｍｍのシート状の柔軟層（Ｃ）を重ね、真空プレス機を用いて１５０℃、１５分の条件で積層プレスした試料を作製し、該試料を１００℃の恒温槽内で６０度に傾斜して設置し５００時間経過後の状態を観察し、ガラスが初期の基準位置からずれなかったものを○、ガラスが初期の基準位置からずれたり、シートが溶融したものを×として評価した。 The heat resistance of the flexible layer (C) in the present invention is determined by various characteristics of the ethylene-α-olefin random copolymer (C-1) (crystal melting peak temperature, crystal melting heat amount, MFR, molecular weight, etc.) and ethylene-α- Although it is affected by various properties (crystal melting peak temperature, crystal melting heat, MFR, molecular weight, etc.) of the olefin block copolymer (C-2), in particular, ethylene-α-olefin block copolymer (C-2) The crystal melting peak temperature is strongly affected.
As described above, if the crystal melting peak temperature of the ethylene-α-olefin block copolymer (C-2) in the flexible layer (C) is 100 ° C. or higher, the heat resistance of the flexible layer (C) in the present invention is ensured. I can do it. And since a front surface protection sheet has the lowest heat resistance and elastic modulus of a flexible layer (C) in the layer which comprises a member, a flexible layer (C) determines the performance about the heat resistance of a front surface protection sheet.
In the present invention, the heat resistance of the flexible layer (C) is 0 mm between white plate glass having a thickness of 3 mm (size: length 75 mm, width 25 mm) and an aluminum plate having a thickness of 5 mm (size: length 120 mm, width 60 mm). .5mm sheet-like flexible layer (C) is stacked, and a sample is laminated and pressed using a vacuum press machine at 150 ° C for 15 minutes, and the sample is inclined at 60 ° C in a 100 ° C constant temperature bath. Then, after observing the state after 500 hours, the case where the glass did not deviate from the initial reference position was evaluated as ◯, and the case where the glass deviated from the initial reference position or the sheet was melted was evaluated as x.
　本発明における柔軟層（Ｃ）の全光線透過率は、適用する太陽電池の種類、例えばアモルファスの薄膜系シリコン型などや太陽電子素子に届く太陽光を遮らない部位に適用する場合には、あまり重視されないこともあるが、太陽電池の光電変換効率や各種部材を重ね合わせる時のハンドリング性などを考慮し、通常、８５％以上であることが好ましく、８７％以上であることがより好ましく、９０％以上であることがさらに好ましい。 The total light transmittance of the flexible layer (C) in the present invention is not so much when applied to a type of solar cell to be applied, for example, an amorphous thin film silicon type or a portion that does not block sunlight reaching the solar electronic element. Although it may not be regarded as important, it is usually preferably 85% or more, more preferably 87% or more, taking into consideration the photoelectric conversion efficiency of the solar cell and handling properties when various members are superimposed, 90% % Or more is more preferable.
　本発明における柔軟層（Ｃ）の柔軟性、耐熱性および透明性については背反特性になり易い。具体的には、柔軟性を向上させるために用いる樹脂組成物の結晶性を低下させ過ぎると、耐熱性が低下し不十分となる。一方、耐熱性を向上させるために用いる樹脂組成物の結晶性を向上させ過ぎると、透明性が低下し不十分となる。本発明においては、これらのバランスを柔軟性の指標として動的粘弾性測定における振動周波数１０Ｈｚ、温度２０℃の貯蔵弾性率（Ｅ´）、耐熱性の指標として示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解ピーク温度および透明性の指標として全光線透過率を用いた場合、３つの指標が、貯蔵弾性率（Ｅ´）が１～２０００ＭＰａ、結晶融解ピーク温度が１００℃以上、全光線透過率８５％以上であることが好ましく、貯蔵弾性率（Ｅ´）が５～５００ＭＰａ、結晶融解ピーク温度が１０５～１４５℃、全光線透過率８５％以上であることがさらに好ましく、貯蔵弾性率（Ｅ´）が１０～１００ＭＰａ、結晶融解ピーク温度が１１０～１４５℃、全光線透過率８７％以上であることが特に好ましい。 The flexibility, heat resistance and transparency of the flexible layer (C) in the present invention are likely to be contradictory characteristics. Specifically, if the crystallinity of the resin composition used for improving flexibility is excessively lowered, the heat resistance is lowered and becomes insufficient. On the other hand, if the crystallinity of the resin composition used for improving the heat resistance is excessively improved, the transparency is lowered and becomes insufficient. In the present invention, the balance is used as an index of flexibility, the vibration frequency is 10 Hz in dynamic viscoelasticity measurement, the storage elastic modulus (E ′) at a temperature of 20 ° C., and the heating rate is 10 ° C. in differential scanning calorimetry as an index of heat resistance. When the total light transmittance is used as an index of crystal melting peak temperature and transparency measured in terms of / min, three indices are storage elastic modulus (E ′) of 1 to 2000 MPa, and crystal melting peak temperature is 100 ° C. or higher. The total light transmittance is preferably 85% or more, the storage elastic modulus (E ′) is 5 to 500 MPa, the crystal melting peak temperature is 105 to 145 ° C., and the total light transmittance is more preferably 85% or more. It is particularly preferable that the storage elastic modulus (E ′) is 10 to 100 MPa, the crystal melting peak temperature is 110 to 145 ° C., and the total light transmittance is 87% or more.
　上記柔軟層（Ｃ）の厚さは、落下物による防湿層破損・防湿機能の劣下を抑制するために５０～１００μｍ程度であり、取り扱いの点から、１５０～７５０μｍが好ましく、３００～５００μｍが更に好ましい。 The thickness of the flexible layer (C) is about 50 to 100 μm in order to suppress damage to the moisture-proof layer due to falling objects and deterioration of the moisture-proof function, and is preferably 150 to 750 μm, preferably 300 to 500 μm from the viewpoint of handling. Further preferred.
　本発明に用いられるエチレン－α－オレフィンランダム共重合体（Ｃ－１）のメルトフローレート（ＭＦＲ）は、特に制限されるものではないが、通常、ＭＦＲ（ＪＩＳ Ｋ７２１０、温度：１９０℃、荷重：２１．１８Ｎ）が、０．５～１００ｇ／１０ｍｉｎ程度、好ましくは２～５０ｇ／１０ｍｉｎ、さらに好ましくは３～３０ｇ／１０ｍｉｎであるものが用いられる。ここで、ＭＦＲは、シートを成形する際の成形加工性などを考慮して選択すればよい。例えば、シートをカレンダー成形する場合には、シートを成形ロールから引き剥がす際のハンドリング性からＭＦＲは、比較的低い値、具体的には０．５～５ｇ／１０ｍｉｎ程度が好ましく、また、Ｔダイを用いて押出成形する場合には、押出負荷を低減させ押出量を増大させる観点からＭＦＲは、２～５０ｇ／１０ｍｉｎが好ましく、さらに好ましくは３～３０ｇ／１０ｍｉｎであるものを用いればよい。 The melt flow rate (MFR) of the ethylene-α-olefin random copolymer (C-1) used in the present invention is not particularly limited, but is usually MFR (JIS K7210, temperature: 190 ° C., load) 21.18N) is about 0.5 to 100 g / 10 min, preferably 2 to 50 g / 10 min, more preferably 3 to 30 g / 10 min. Here, the MFR may be selected in consideration of the formability when the sheet is formed. For example, when calendering a sheet, the MFR is preferably a relatively low value, specifically about 0.5 to 5 g / 10 min from the handling property when the sheet is peeled off from the molding roll. In the case of extrusion molding using a, MFR is preferably 2 to 50 g / 10 min, more preferably 3 to 30 g / 10 min from the viewpoint of reducing the extrusion load and increasing the extrusion rate.
　本発明に用いられるエチレン－α－オレフィンランダム共重合体（Ｃ－１）は、条件（１）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解熱量が０～７０Ｊ／ｇを満足することが重要であり、好ましくは、５～７０Ｊ／ｇ、さらに好ましくは、１０～６５Ｊ／ｇである。該範囲内であれば、本発明の太陽電池封止材の柔軟性や透明性（全光線透過率）などが確保されるため好ましい。また、結晶融解熱量が０Ｊ／ｇ以上であれば、原料ペレットのブロッキングなどの不具合も起こり難い為好ましい。ここで、該結晶融解熱量の参考値としては、汎用の高密度ポリエチレン（ＨＤＰＥ）が１７０～２２０Ｊ／ｇ程度、低密度ポリエチレン樹脂（ＬＤＰＥ）や直鎖状低密度ポリエチレン（ＬＬＤＰＥ）が１００～１６０Ｊ／ｇ程度である。
　また、本発明に用いられるエチレン－α－オレフィンランダム共重合体（Ｃ－１）の結晶融解ピーク温度は、特に限定されるものではないが、通常、１００℃未満であり、好ましくは３０～９０℃である。ここで、該結晶融解ピーク温度の参考値としては、汎用の高密度ポリエチレン（ＨＤＰＥ）が１３０～１４５℃程度、低密度ポリエチレン樹脂（ＬＤＰＥ）や直鎖状低密度ポリエチレン（ＬＬＤＰＥ）が１００～１２５℃程度である。すなわち、本発明に用いられるエチレン－α－オレフィンランダム共重合体（Ｃ－１）単独では、示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解ピーク温度が１００℃以上であり、かつ、結晶融解熱量が５～７０Ｊ／ｇを達成することは困難である。 The ethylene-α-olefin random copolymer (C-1) used in the present invention has a heat of crystal melting of 0 to 70 J / g measured at a heating rate of 10 ° C./min in the condition (1) differential scanning calorimetry. It is important to satisfy, preferably 5 to 70 J / g, more preferably 10 to 65 J / g. If it is in this range, since the softness | flexibility, transparency (total light transmittance), etc. of the solar cell sealing material of this invention are ensured, it is preferable. Moreover, it is preferable if the heat of crystal fusion is 0 J / g or more because problems such as blocking of raw material pellets are unlikely to occur. Here, as reference values for the heat of crystal melting, general-purpose high-density polyethylene (HDPE) is about 170 to 220 J / g, and low-density polyethylene resin (LDPE) and linear low-density polyethylene (LLDPE) are 100 to 160 J. / G or so.
The crystal melting peak temperature of the ethylene-α-olefin random copolymer (C-1) used in the present invention is not particularly limited, but is usually less than 100 ° C., preferably 30 to 90. ° C. Here, as reference values for the crystal melting peak temperature, general-purpose high-density polyethylene (HDPE) is about 130 to 145 ° C., and low-density polyethylene resin (LDPE) and linear low-density polyethylene (LLDPE) are 100 to 125. It is about ℃. That is, with the ethylene-α-olefin random copolymer (C-1) used alone in the present invention, the crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or higher, In addition, it is difficult to achieve a crystal melting heat quantity of 5 to 70 J / g.
　本発明に用いられるエチレン－α－オレフィンランダム共重合体（Ｃ－１）の具体例としては、ダウ・ケミカル（株）製の商品名「エンゲージ（Ｅｎｇａｇｅ）」、「アフィニティー（Ａｆｆｉｎｉｔｙ）」、三井化学（株）製の商品名「タフマーＡ（ＴＡＦＭＥＲ Ａ）」、「タフマーＰ（ＴＡＦＭＥＲ Ｐ）」、日本ポリエチレン（株）製の商品名「カーネル（Ｋａｒｎｅｌ）」等を例示することができる。 Specific examples of the ethylene-α-olefin random copolymer (C-1) used in the present invention include trade names “Engage”, “Affinity” manufactured by Dow Chemical Co., Ltd., Mitsui Examples include trade names “TAFMER A”, “TAFMER P” manufactured by Kagaku Co., Ltd., and “kernel” manufactured by Nippon Polyethylene Co., Ltd.
　本発明に用いられるエチレン－α－オレフィンブロック共重合体（Ｃ－２）のメルトフローレート（ＭＦＲ）は、特に制限されるものではないが、通常、ＭＦＲ（ＪＩＳ Ｋ７２１０、温度：１９０℃、荷重：２１．１８Ｎ）が、０．５～１００ｇ／１０ｍｉｎ程度、より好ましくは１～５０ｇ／１０ｍｉｎ、さらに好ましくは１～３０ｇ／１０ｍｉｎ、特に好ましくは１～１０ｇ／１０ｍｉｎであるものが用いられる。 The melt flow rate (MFR) of the ethylene-α-olefin block copolymer (C-2) used in the present invention is not particularly limited, but is usually MFR (JIS K7210, temperature: 190 ° C., load) : 21.18N) is about 0.5 to 100 g / 10 min, more preferably 1 to 50 g / 10 min, still more preferably 1 to 30 g / 10 min, and particularly preferably 1 to 10 g / 10 min.
　本発明に用いられるエチレン－α－オレフィンブロック共重合体（Ｃ－２）は、示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解ピーク温度が１００℃以上であり、かつ、結晶融解熱量が５～７０Ｊ／ｇ（条件（２））を満足することが重要である。該結晶融解ピーク温度は好ましくは１０５℃以上、さらに好ましくは１１０℃以上であり、上限は通常１４５℃である。また、結晶融解熱量は好ましくは１０～６０Ｊ／ｇ、さらに好ましくは１５～５５Ｊ／ｇである。 The ethylene-α-olefin block copolymer (C-2) used in the present invention has a crystal melting peak temperature of 100 ° C. or higher measured at a heating rate of 10 ° C./min in differential scanning calorimetry, It is important that the heat of fusion satisfies 5 to 70 J / g (condition (2)). The crystal melting peak temperature is preferably 105 ° C. or higher, more preferably 110 ° C. or higher, and the upper limit is usually 145 ° C. The heat of crystal melting is preferably 10 to 60 J / g, more preferably 15 to 55 J / g.
　本発明に用いられるエチレン－α－オレフィンブロック共重合体（Ｃ－２）のブロック構造は、既述の条件（２）を満足すれば特に限定されるものではないが、柔軟性、耐熱性、透明性等のバランス化の観点から、コモノマー含有率、結晶性、密度、結晶融解ピーク温度（融点Ｔｍ）、又はガラス転移温度（Ｔｇ）の異なる２つ以上、好ましくは３つ以上のセグメント又はブロックを含有するマルチブロック構造であることが好ましい。具体的には、完全対称ブロック、非対称ブロック、テ－パ－ドブロック構造（ブロック構造の比率が主鎖内で漸増する構造）などが挙げられる。該マルチブロック構造を有する共重合体の構造や製造方法については、国際公開第２００５／０９０４２５号パンフレット（ＷＯ２００５／０９０４２５）、国際公開第２００５／０９０４２６号パンフレット（ＷＯ２００５／０９０４２６）、および国際公開第２００５／０９０４２７号パンフレット（ＷＯ２００５／０９０４２７）などで詳細に開示されているものを採用することができる。 The block structure of the ethylene-α-olefin block copolymer (C-2) used in the present invention is not particularly limited as long as the above-described condition (2) is satisfied, but flexibility, heat resistance, Two or more, preferably three or more segments or blocks having different comonomer contents, crystallinity, density, crystal melting peak temperature (melting point Tm), or glass transition temperature (Tg) from the viewpoint of balancing such as transparency A multi-block structure containing Specific examples include a completely symmetric block, an asymmetric block, and a tapered block structure (a structure in which the ratio of the block structure gradually increases in the main chain). Regarding the structure and production method of the copolymer having the multi-block structure, International Publication No. 2005/090425 (WO2005 / 090425), International Publication No. 2005/090426 (WO2005 / 090426), and International Publication No.2005. / 090427 pamphlet (WO2005 / 090427) or the like can be employed.
　前記マルチブロック構造を有するエチレン－α－オレフィンブロック共重合体について、以下、詳細に説明する。
　該マルチブロック構造を有するエチレン－α－オレフィンブロック共重合体は、本発明において好適に使用でき、α－オレフィンとして１－オクテンを共重合成分とするエチレン－オクテンマルチブロック共重合体が好ましい。該ブロック共重合体としては、エチレンに対してオクテン成分が多く（約１５～２０モル％）共重合されたほぼ非晶性のソフトセグメントと、エチレンに対してオクテン成分が少なく（約２モル％未満）共重合された結晶融解ピーク温度が１１０～１４５℃である高結晶性のハードセグメントが、各々２つ以上存在するマルチブロック共重合体が好ましい。これらのソフトセグメントとハードセグメントの連鎖長や比率を制御することにより、柔軟性と耐熱性の両立を達成することができる。
　該マルチブロック構造を有する共重合体の具体例としては、ダウ・ケミカル（株）製の商品名「インフューズ（Ｉｎｆｕｓｅ）」が挙げられる。 The ethylene-α-olefin block copolymer having the multi-block structure will be described in detail below.
The ethylene-α-olefin block copolymer having a multiblock structure can be suitably used in the present invention, and an ethylene-octene multiblock copolymer having 1-octene as a copolymerization component as an α-olefin is preferable. As the block copolymer, an almost non-crystalline soft segment copolymerized with a large amount of octene component (about 15 to 20 mol%) with respect to ethylene and a small amount of octene component (about 2 mol% with respect to ethylene). Less) a multiblock copolymer having two or more highly crystalline hard segments each having a copolymerized crystal melting peak temperature of 110 to 145 ° C. is preferred. By controlling the chain length and ratio of these soft segments and hard segments, both flexibility and heat resistance can be achieved.
As a specific example of the copolymer having the multi-block structure, trade name “Infuse” manufactured by Dow Chemical Co., Ltd. may be mentioned.
　本発明に用いられるエチレン－α－オレフィンブロック共重合体（Ｃ－２）のメルトフローレート（ＭＦＲ）は、特に制限されるものではないが、通常、ＭＦＲ（ＪＩＳ　Ｋ７２１０、温度：１９０℃、荷重：２１．１８Ｎ）が、０．５～１００ｇ／１０ｍｉｎ程度、より好ましくは１～５０ｇ／１０ｍｉｎ、さらに好ましくは１～３０ｇ／１０ｍｉｎ、特に好ましくは１～１０ｇ／１０ｍｉｎであるものが用いられる。 The melt flow rate (MFR) of the ethylene-α-olefin block copolymer (C-2) used in the present invention is not particularly limited, but usually MFR (JIS K7210, temperature: 190 ° C., load) : 21.18N) is about 0.5 to 100 g / 10 min, more preferably 1 to 50 g / 10 min, still more preferably 1 to 30 g / 10 min, and particularly preferably 1 to 10 g / 10 min.
　ここで、ＭＦＲは、シートを成形する際の成形加工性などを考慮して選択すればよい。具体的には、シートをカレンダー成形する場合には、シートを成形ロールから引き剥がす際のハンドリング性からＭＦＲは、比較的低い方、具体的には０．５～５ｇ／１０ｍｉｎ程度が好ましく、また、Ｔダイを用いて押出成形する場合には、押出負荷を低減させ押出量を増大させる観点からＭＦＲは、１～３０ｇ／１０ｍｉｎであるものが好適に用いられる。さらに、太陽電池素子（セル）を封止する時の密着性や回り込み易さの観点からは、ＭＦＲは、３～５０ｇ／１０ｍｉｎであるものが好適に用いられる。 Here, the MFR may be selected in consideration of the formability when the sheet is formed. Specifically, when calendering a sheet, the MFR is preferably relatively low, specifically about 0.5 to 5 g / 10 min from the handling property when the sheet is peeled off from the molding roll, In the case of extrusion molding using a T die, an MFR of 1 to 30 g / 10 min is preferably used from the viewpoint of reducing the extrusion load and increasing the extrusion amount. Further, from the viewpoint of adhesion and ease of wraparound when sealing the solar cell element (cell), an MFR of 3 to 50 g / 10 min is preferably used.
　次に、柔軟層（Ｃ）中におけるエチレン－α－オレフィンランダム共重合体（Ｃ－１）とエチレン－α－オレフィンブロック共重合体（Ｃ－２）の含有量は、柔軟性、耐熱性、透明性等の優れたバランスを有する観点から、それぞれ、好ましくは、５０～９９質量％、１～５０質量％であり、より好ましくは、６０～９８質量％、２～４０質量％であり、更に好ましくは、７０～９７質量％、３～３０質量％である。
　本発明の太陽電池用前面保護シートは、上述の耐候層（Ａ）と防湿層（Ｂ）とを柔軟層（Ｃ）を介して積層してなるものであるが、本発明の太陽電池用前面保護シート・封止材積層体は、上記太陽電池用前面保護シートに、封止材（Ｄ）を積層してなる。 Next, the contents of the ethylene-α-olefin random copolymer (C-1) and the ethylene-α-olefin block copolymer (C-2) in the flexible layer (C) are flexibility, heat resistance, From the viewpoint of having an excellent balance such as transparency, it is preferably 50 to 99% by mass, 1 to 50% by mass, more preferably 60 to 98% by mass, 2 to 40% by mass, respectively. Preferably, they are 70 to 97% by mass and 3 to 30% by mass.
The front protective sheet for a solar cell of the present invention is formed by laminating the above-mentioned weather resistant layer (A) and moisture-proof layer (B) via a flexible layer (C). The protective sheet / encapsulant laminate is formed by laminating the encapsulant (D) on the solar cell front protective sheet.
＜封止材（Ｄ）＞
　封止材（Ｄ）は、太陽電池素子を封止するために用いられ、前記柔軟層（Ｂ）と同様、下記(１)の条件を満足するエチレン－α－オレフィンランダム共重合体（Ｄー１）と下記(２)の条件を満足するエチレン－α－オレフィンブロック共重合体（Ｄー２）とを含有する。
　　（１）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解熱量が０～７０Ｊ／ｇ
　　（２）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解ピーク温度が１００℃以上であり、かつ、結晶融解熱量が５～７０Ｊ／ｇ <Encapsulant (D)>
The encapsulant (D) is used to encapsulate the solar cell element and, like the flexible layer (B), an ethylene-α-olefin random copolymer (D-) that satisfies the following condition (1): 1) and an ethylene-α-olefin block copolymer (D-2) satisfying the following condition (2).
(1) The heat of crystal fusion measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 70 J / g.
(2) The crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or more, and the crystal melting heat amount is 5 to 70 J / g.
　本発明において、(１)の条件を満足するエチレン－α－オレフィンランダム共重合体（Ｄー１）としては、上記の前面保護シートに用いたエチレン－α－オレフィンランダム共重合体（Ｃー１）について述べたものと同様のものを用いることができ、(２)の条件を満足するエチレン－α－オレフィンブロック共重合体（Ｄー２）としては、上記の前面保護シートに用いたエチレン－α－オレフィンブロック共重合体（Ｃー２）について述べたものと同様のものを用いることができる。
　本発明においては、封止材（Ｄ）を構成するエチレン－α－オレフィンランダム共重合体（Ｄー１）及びエチレン－α－オレフィンブロック共重合体（Ｄー２）の各々に用いられるα－オレフィンの種類は、同一であってもよいし、異なっていてもよいが、本発明においては、同一である方が、混合した際の相溶性や前面保護シートの透明性、すなわち、太陽電池の光電変換効率が向上するため好ましい。 In the present invention, as the ethylene-α-olefin random copolymer (D-1) satisfying the condition (1), the ethylene-α-olefin random copolymer (C-1) used for the front protective sheet is used. The same ethylene-α-olefin block copolymer (D-2) that satisfies the condition (2) can be used as the ethylene- The same as those described for the α-olefin block copolymer (C-2) can be used.
In the present invention, the α-olefin used for each of the ethylene-α-olefin random copolymer (D-1) and the ethylene-α-olefin block copolymer (D-2) constituting the sealing material (D). The types of olefins may be the same or different, but in the present invention, the same olefin is compatible when mixed and the transparency of the front protective sheet, that is, the solar cell. It is preferable because photoelectric conversion efficiency is improved.
　上記エチレン－α－オレフィンランダム共重合体（Ｄー１）とエチレン－α－オレフィンブロック共重合体（Ｄー２）を含有する封止材（Ｄ）の組成についても、上記の柔軟層（Ｃ）の組成と同様であり、同様の他の樹脂あるいは添加剤を含有することができる。得られる封止材の貯蔵弾性率、耐熱性、全光線透過率等の性状、これらの関係についても、前記層（Ｃ）と同様である。本発明においては、封止材（Ｄ）としては、後述する太陽電池モジュール作製時の防湿性能低下防止の点から、柔軟層（Ｃ）と同一の組成、性状を有するものが好ましい。
　封止材（Ｄ）の厚みは、特に限定されるものではないが、通常、０．０５～１ｍｍ程度であり、好ましくは０．１～０．７ｍｍ，より好ましくは０．３～０．５ｍｍのシート状で用いられる。 Regarding the composition of the encapsulant (D) containing the ethylene-α-olefin random copolymer (D-1) and the ethylene-α-olefin block copolymer (D-2), the flexible layer (C ) And can contain other similar resins or additives. Properties of the obtained sealing material such as storage elastic modulus, heat resistance, total light transmittance, and the relationship thereof are the same as those of the layer (C). In the present invention, as the sealing material (D), those having the same composition and properties as the flexible layer (C) are preferable from the viewpoint of preventing the moisture-proof performance from being lowered when a solar cell module described later is produced.
The thickness of the sealing material (D) is not particularly limited, but is usually about 0.05 to 1 mm, preferably 0.1 to 0.7 mm, more preferably 0.3 to 0.5 mm. It is used in the form of a sheet.
＜太陽電池用前面保護シート、太陽電池用前面保護シート・封止材積層体及びその製造方法＞
　本発明の太陽電池用前面保護シート及び太陽電池用前面保護シート・封止材積層体には、本発明の主旨を逸脱しない範囲で、諸物性（柔軟性、耐熱性、透明性、接着性など）や成形加工性あるいは経済性などをさらに向上させる目的で上述したエチレン－α－オレフィンランダム共重合体（Ｃ－１）あるいは（Ｄ－１）やエチレン－α－オレフィンブロック共重合体（Ｃ－２）あるいは（Ｄ－２）以外の樹脂を混合することができる。該樹脂としては、例えば、他のポリオレフィン系樹脂や各種エラストマー（オレフィン系、スチレン系など）、カルボキシル基、アミノ基、イミド基、水酸基、エポキシ基、オキサゾリン基、チオール基、シラノール基などの極性基で変性された樹脂および粘着付与樹脂などが挙げられる。 <Solar Cell Front Protective Sheet, Solar Cell Front Protective Sheet / Sealing Material Laminate, and Method for Producing the Same>
The solar cell front protective sheet and solar cell front protective sheet / sealing material laminate according to the present invention have various physical properties (flexibility, heat resistance, transparency, adhesiveness, etc.) without departing from the gist of the present invention. ), The above-mentioned ethylene-α-olefin random copolymer (C-1) or (D-1) or ethylene-α-olefin block copolymer (C-) Resins other than 2) or (D-2) can be mixed. Examples of the resin include other polyolefin resins and various elastomers (olefin-based, styrene-based, etc.), polar groups such as carboxyl groups, amino groups, imide groups, hydroxyl groups, epoxy groups, oxazoline groups, thiol groups, silanol groups, and the like. And a resin modified with a tackifier resin.
　該粘着付与樹脂としては、石油樹脂、テルペン樹脂、クマロン－ インデン樹脂、ロジン系樹脂、またはそれらの水素添加誘導体などが挙げられる。具体的には、石油樹脂としては、シクロペンタジエンまたはその二量体からの脂環式石油樹脂やＣ9成分からの芳香族石油樹脂があり、テルペン樹脂としてはβ－ピネンからのテルペン樹脂やテルペン－フェノール樹脂が、また、ロジン系樹脂としては、ガムロジン、ウッドロジン等のロジン樹脂、グリセリンやペンタエリスリトール等で変性したエステル化ロジン樹脂などを例示することができる。また、該粘着付与樹脂は主に分子量により種々の軟化温度を有するものが得られるが、既述の共重合体（Ｃ－１）、共重合体（Ｃ－２）と混合した場合、あるいは共重合体（Ｄー１）、共重合体（Ｄー２）と混合した場合の相溶性、色調や熱安定性などの点から軟化温度が１００～１５０℃、好ましくは１２０～１４０℃の脂環式石油樹脂の水素添加誘導体が特に好ましい。上述した共重合体（Ｃ－１）や共重合体（Ｃ－２）以外、あるいは共重合体（Ｄー１）、共重合体（Ｄー２）以外の樹脂を混合する場合は、柔軟層（Ｃ）あるいは封止材（Ｄ）中、通常、樹脂組成物を１００質量部とした場合、２０質量部以下が好ましく、１０質量部以下がさらに好ましい。 Examples of the tackifying resin include petroleum resins, terpene resins, coumarone-indene resins, rosin resins, and hydrogenated derivatives thereof. Specifically, the petroleum resin includes cyclopentadiene or an alicyclic petroleum resin derived from a dimer thereof and an aromatic petroleum resin derived from a C 9 component, and the terpene resin includes terpene resin and terpene derived from β-pinene. -Phenol resin, and examples of rosin resins include rosin resins such as gum rosin and wood rosin, and esterified rosin resins modified with glycerin, pentaerythritol, and the like. The tackifying resin can be obtained with various softening temperatures mainly depending on the molecular weight, but when mixed with the copolymer (C-1) and copolymer (C-2) described above, Aliphatic ring having a softening temperature of 100 to 150 ° C., preferably 120 to 140 ° C., in view of compatibility, color tone and thermal stability when mixed with polymer (D-1) and copolymer (D-2) Particularly preferred are hydrogenated derivatives of formula petroleum resins. When a resin other than the above-mentioned copolymer (C-1) or copolymer (C-2), or a resin other than copolymer (D-1) or copolymer (D-2) is mixed, a flexible layer In (C) or the sealing material (D), when the resin composition is usually 100 parts by mass, it is preferably 20 parts by mass or less, and more preferably 10 parts by mass or less.
　また、本発明の太陽電池用前面保護シート及び太陽電池用前面保護シート・封止材積層体には、必要に応じて、種々の添加剤を添加することができる。該添加剤としては、例えば、シランカップリング剤、酸化防止剤、紫外線吸収剤、耐候安定剤、光拡散剤、造核剤、顔料（例えば白色顔料）、難燃剤、変色防止剤などが挙げられる。本発明においては、シランカップリング剤、酸化防止剤、紫外線吸収剤、耐候安定剤から選ばれる少なくとも一種の添加剤が添加されていることが後述する理由等から好ましい。また、本発明においては、例えば、高度の耐熱性を要求される場合は架橋剤および／または架橋助剤を配合してもよい。 In addition, various additives can be added to the solar cell front protective sheet and the solar cell front protective sheet / sealing material laminate of the present invention as necessary. Examples of the additive include a silane coupling agent, an antioxidant, an ultraviolet absorber, a weathering stabilizer, a light diffusing agent, a nucleating agent, a pigment (for example, a white pigment), a flame retardant, and a discoloration preventing agent. . In the present invention, it is preferable that at least one additive selected from a silane coupling agent, an antioxidant, an ultraviolet absorber, and a weathering stabilizer is added for reasons described later. In the present invention, for example, when a high heat resistance is required, a crosslinking agent and / or a crosslinking aid may be blended.
　シランカップリング剤の例としては、ビニル基、アクリロキシ基、メタクリロキシ基のような不飽和基、アミノ基、エポキシ基などとともに、アルコキシ基のような加水分解可能な基を有する化合物を挙げることができる。シランカップリング剤の具体例としては、Ｎ－（β－アミノエチル）－γ－アミノプロピルトリメトキシシラン、Ｎ－（β－アミノエチル）－γ－アミノプロピルメチルジメトキシシラン、γ－アミノプロピルトリエトキシシラン、γ－グリシドキシプロピルトリメトキシシラン、γ－メタクリロキシプロピルトリメトキシシランなどを例示することができる。本発明においては、接着性が良好であり、黄変などの変色が少ないこと等からγ－グリシドキシプロピルトリメトキシシランやγ－メタクリロキシプロピルトリメトキシシランが好ましく用いられる。該シランカップリング剤の添加量は、太陽電池用前面保護シート中、または太陽電池用前面保護シート・封止材積層体を構成する各樹脂層中、通常、０．１～５質量％程度であり、０．２～３質量％添加することが好ましい。また、シランカップリング剤と同様に、有機チタネート化合物などのカップリング剤も有効に活用できる。 Examples of silane coupling agents include compounds having a hydrolyzable group such as an alkoxy group together with an unsaturated group such as a vinyl group, an acryloxy group or a methacryloxy group, an amino group or an epoxy group. . Specific examples of the silane coupling agent include N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, and γ-aminopropyltriethoxy. Examples thereof include silane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane. In the present invention, γ-glycidoxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane are preferably used because of good adhesiveness and little discoloration such as yellowing. The amount of the silane coupling agent added is usually about 0.1 to 5% by mass in the solar cell front protective sheet or in each resin layer constituting the solar cell front protective sheet / sealing material laminate. It is preferable to add 0.2 to 3% by mass. In addition, similar to the silane coupling agent, a coupling agent such as an organic titanate compound can be effectively used.
　酸化防止剤としては、種々の市販品が適用でき、モノフェノール系、ビスフェノール系、高分子型フェノール系、硫黄系、ホスファイト系など各種タイプのものを挙げることができる。モノフェノール系としては、例えば、２，６－ジ－ｔｅｒｔ－ブチル－ｐ－クレゾール、ブチル化ヒドロキシアニゾール、２，６－ジ－ｔｅｒｔ－ブチル－４－エチルフェノールなどを挙げることができる。ビスフェノール系としては、２，２′－メチレン－ビス－（４－メチル－６－ｔｅｒｔ－ブチルフェノール）、２，２′－メチレン－ビス－（４－エチル－６－ｔｅｒｔ－ブチルフェノール）、４，４′－チオビス－（３－メチル－６－ｔｅｒｔ－ブチルフェノール）、４，４′－ブチリデン－ビス－（３－メチル－６－ｔｅｒｔ－ブチルフェノール）、３，９－ビス〔｛１，１－ジメチル－２－｛β－（３－ｔｅｒｔ－ブチル－４－ヒドロキシ－５－メチルフェニル）プロピオニルオキシ｝エチル｝２，４，９，１０－テトラオキサスピロ〕５，５－ウンデカンなどを挙げることができる。 As the antioxidant, various commercial products can be applied, and various types such as monophenol type, bisphenol type, polymer type phenol type, sulfur type and phosphite type can be exemplified. Examples of monophenols include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, and 2,6-di-tert-butyl-4-ethylphenol. Examples of bisphenols include 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4 '-Thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidene-bis- (3-methyl-6-tert-butylphenol), 3,9-bis [{1,1-dimethyl- 2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl} 2,4,9,10-tetraoxaspiro] 5,5-undecane.
　高分子フェノール系としては、１，１，３－トリス－（２－メチル－４－ヒドロキシ－５－ｔｅｒｔ－ブチルフェニル）ブタン、１，３，５－トリメチル－２，４，６－トリス（３，５－ジ－ｔｅｒｔ－ブチル－４－ビドロキシベンジル）ベンゼン、テトラキス－｛メチレン－３－（３′，５′－ジ－ｔｅｒｔ－ブチル－４′－ヒドロキスフェニル）プロピオネート｝メタン、ビス｛（３，３′－ビス－４′－ヒドロキシ－３′－ｔｅｒｔ－ブチルフェニル）ブチリックアシッド｝グルコールエステル、１，３，５－トリス（３′，５′－ジ－ｔｅｒｔ－ブチル－４′－ヒドロキシベンジル）－ｓ－トリアジン－２，４，６－（１Ｈ，３Ｈ，５Ｈ）トリオン、トリフェノール（ビタミンＥ）などを挙げることができる。 Examples of the high molecular phenolic group include 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3 , 5-di-tert-butyl-4-bidoxybenzyl) benzene, tetrakis- {methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate} methane, bis { (3,3′-bis-4′-hydroxy-3′-tert-butylphenyl) butyric acid} glycol ester, 1,3,5-tris (3 ′, 5′-di-tert-butyl-4 '-Hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione, triphenol (vitamin E) and the like.
　硫黄系としては、ジラウリルチオジプロピオネート、ジミリスチルチオジプロピオネート、ジステアリルチオプロピオネートなどを挙げることができる。 Examples of sulfur-based compounds include dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiopropionate.
　ホスファイト系としては、トリフェニルホスファイト、ジフェニルイソデシルホスファイト、フェニルジイソデシルホスファイト、４，４′－ブチリデン－ビス（３－メチル－６－ｔｅｒｔ－ブチルフェニル－ジ－トリデシル）ホスファイト、サイクリックネオペンタンテトライルビス（オクタデシルホスファイト）、トリス（モノおよび／またはジ）フェニルホスファイト、ジイソデシルペンタエリスリトールジホスファイト、９，１０－ジヒドロ－９－オキサ－１０－ホスファフェナスレン－１０－オキサイド、１０－（３，５－ジ－ｔｅｒｔ－ブチル－４－ヒドロキシベンジル）－９，１０－ジヒドロ－９－オキサ－１０－ホスファフェナンスレン－１０－オキサイド、１０－デシロキシ－９，１０－ジヒドロ－９－オキサ－１０－ホスファフェナンスレン、サイクリックネオペンタンテトライルビス（２，４－ジ－ｔｅｒｔ－ブチルフェニル）ホスファイト、サイクリックネオペンタンテトライルビス（２，６－ジ－ｔｅｒｔ－メチルフェニル）ホスファイト、２，２－メチレンビス（４，６－ｔｅｒｔ－ブチルフェニル）オクチルホスファイトなどを挙げることができる。 Examples of phosphites include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, Crick neopentanetetrayl bis (octadecyl phosphite), tris (mono and / or di) phenyl phosphite, diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10 -Dihydro-9-oxa-10- Sphaphenanthrene, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-tert-methylphenyl) phosphite, 2 , 2-methylenebis (4,6-tert-butylphenyl) octyl phosphite.
　本発明においては、酸化防止剤の効果、熱安定性、経済性等からフェノール系およびホスファイト系の酸化防止剤が好ましく用いられ、両者を組み合わせて用いることがさらに好ましい。該酸化防止剤の添加量は、太陽電池用前面保護シート中、または太陽電池用前面保護シート・封止材積層体を構成する各樹脂層中、通常、０．１～１質量％程度であり、０．２～０．５質量％添加することが好ましい。 In the present invention, phenol-based and phosphite-based antioxidants are preferably used in view of the effect of the antioxidant, thermal stability, economy and the like, and it is more preferable to use a combination of both. The addition amount of the antioxidant is usually about 0.1 to 1% by mass in the front protective sheet for solar cells or in each resin layer constituting the front protective sheet / sealant laminate for solar cells. 0.2 to 0.5% by mass is preferably added.
　紫外線吸収剤としては、種々の市販品が適用でき、ベンゾフェノン系、ベンゾトリアゾール系、トリアジン系、サリチル酸エステル系など各種タイプのものを挙げることができる。ベンゾフェノン系紫外線吸収剤としては、例えば、２－ヒドロキシ－４－メトキシベンゾフェノン、２－ヒドロキシ－４－メトキシ－２’－カルボキシベンゾフェノン、２－ヒドロキシ－４－オクトキシベンゾフェノン、２－ヒドロキシ－４－ｎ－ドデシルオキシベンゾフェノン、２－ヒドロキシ－４－ｎ－オクタデシルオキシベンゾフェノン、２－ヒドロキシ－４－ベンジルオキシベンゾフェノン、２－ヒドロキシ－４－メトキシ－５－スルホベンゾフェノン、２－ヒドロキシ－５－ クロロベンゾフェノン、２，４－ジヒドロキシベンゾフェノン、２，２’－ジヒドロキシ－４－メトキシベンゾフェノン、２，２’－ジヒドロキシ－４，４’－ジメトキシベンゾフェノン、２，２’，４，４’－テトラヒドロキシベンゾフェノンなどを挙げることができる。 As the ultraviolet absorber, various commercially available products can be applied, and various types such as benzophenone-based, benzotriazole-based, triazine-based, and salicylic acid ester-based materials can be exemplified. Examples of benzophenone ultraviolet absorbers include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-n. -Dodecyloxybenzophenone, 2-hydroxy-4-n-octadecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-5-chlorochlorophenone, 2, , 4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, etc. Rukoto can.
　ベンゾトリアゾール系紫外線吸収剤としては、ヒドロキシフェニル置換ベンゾトリアゾール化合物であって、例えば、２－（２－ヒドロキシ－５－メチルフェニル）ベンゾトリアゾール、２－（２－ヒドロキシ－５－ｔ－ブチルフェニル）ベンゾトリアゾール、２－（２－ヒドロキシ－３，５－ジメチルフェニル）ベンゾトリアゾール、２－（２－メチル－４－ヒドロキシフェニル）ベンゾトリアゾール、２－（２－ヒドロキシ－３－メチル－５－ｔ－ブチルフェニル）ベンゾトリアゾール、２－（２－ヒドロキシ－３，５－ジ－ｔ－アミルフェニル）ベンゾトリアゾール、２－（２－ ヒドロキシ－３，５－ジ－ｔ－ブチルフェニル）ベンゾトリアゾールなどを挙げることができる。またトリアジン系紫外線吸収剤としては、２－［４，６－ビス（２，４－ジメチルフェニル）－１，３，５－トリアジン－２－イル］－５－（オクチルオキシ）フェノール、２－（４，６－ジフェニル－１，３，５－トリアジン－２－イル）－５－（ヘキシルオキシ）フェノールなどを挙げることができる。サリチル酸エステル系としては、フェニルサリチレート、ｐ－オクチルフェニルサリチレートなどを挙げることができる。
　該紫外線吸収剤の添加量は、太陽電池用前面保護シート中、または太陽電池用前面保護シート・封止材積層体を構成する各樹脂層中、通常、０．０１～２．０質量％程度であり、０．０５～０．５質量％添加することが好ましい。 Examples of the benzotriazole ultraviolet absorber include hydroxyphenyl-substituted benzotriazole compounds such as 2- (2-hydroxy-5-methylphenyl) benzotriazole and 2- (2-hydroxy-5-tert-butylphenyl). Benzotriazole, 2- (2-hydroxy-3,5-dimethylphenyl) benzotriazole, 2- (2-methyl-4-hydroxyphenyl) benzotriazole, 2- (2-hydroxy-3-methyl-5-t- Butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-amylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, etc. be able to. Examples of triazine ultraviolet absorbers include 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 2- ( Examples include 4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) phenol. Examples of salicylic acid esters include phenyl salicylate and p-octylphenyl salicylate.
The addition amount of the ultraviolet absorber is usually about 0.01 to 2.0% by mass in the front protective sheet for solar cells or in each resin layer constituting the front protective sheet / sealant laminate for solar cells. It is preferable to add 0.05 to 0.5% by mass.
　上記の紫外線吸収剤以外に耐候性を付与する耐候安定剤としては、ヒンダードアミン系光安定化剤が好適に用いられる。ヒンダードアミン系光安定化剤は、紫外線吸収剤のようには紫外線を吸収しないが、紫外線吸収剤と併用することによって著しい相乗効果を示す。 Hindered amine light stabilizers are preferably used as the weather stabilizer for imparting weather resistance in addition to the above ultraviolet absorbers. A hindered amine light stabilizer does not absorb ultraviolet rays like an ultraviolet absorber, but exhibits a remarkable synergistic effect when used together with an ultraviolet absorber.
　ヒンダードアミン系光安定化剤としては、コハク酸ジメチル－１－（２－ヒドロキシエチル）－４－ヒドロキシ－２，２，６，６－テトラメチルピペリジン重縮合物、ポリ［｛６－（１，１，３，３－テトラメチルブチル）アミノ－１，３，５－トリアジン－２，４－ジイル｝｛（２，２，６，６－テトラメチル－４－ピペリジル）イミノ｝ヘキサメチレン｛｛２，２，６，６－テトラメチル－４－ピペリジル｝イミノ｝］、Ｎ，Ｎ′－ビス（３－アミノプロピル）エチレンジアミン－２，４－ビス［Ｎ－ブチル－Ｎ－（１，２，２，６，６－ペンタメチル－４－ピペリジル）アミノ］－６－クロロ－１，３，５－トリアジン縮合物、ビス（２，２，６，６－テトラメチル－４－ピペリジル）セバケート、２－（３，５－ジ－ｔｅｒｔ－４－ヒドロキシベンジル）－２－ｎ－ブチルマロン酸ビス（１，２，２，６，６－ペンタメチル－４－ピペリジル）などを挙げることができる。該ヒンダードアミン系光安定化剤の添加量は、太陽電池用前面保護シート中、または太陽電池用前面保護シート・封止材積層体を構成する各樹脂層中、通常、０．０１～０．５質量％程度であり、０．０５～０．３質量％添加することが好ましい。 Examples of hindered amine light stabilizers include dimethyl-1- (2-hydroxyethyl) succinate-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1 , 3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {{2, 2,6,6-tetramethyl-4-piperidyl} imino}], N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2, 6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3 , 5-Di-tert-4 Hydroxybenzyl) -2-n-butyl malonic acid bis (1,2,2,6,6-pentamethyl-4-piperidyl) and the like. The amount of the hindered amine light stabilizer added is usually 0.01 to 0.5 in the solar cell front protective sheet or in each resin layer constituting the solar cell front protective sheet / sealing material laminate. It is about mass%, and it is preferable to add 0.05 to 0.3 mass%.
　本発明に用いられる耐候層（Ａ）、防湿層（Ｂ）及び柔軟層（Ｃ）並びに封止材（Ｄ）の製膜方法としては、公知の方法、例えば単軸押出機、多軸押出機、バンバリーミキサー、ニーダーなどの溶融混合設備を有し、Ｔダイを用いる押出キャスト法やカレンダー法等を採用することができ、特に限定されるものではないが、本発明においては、ハンドリング性や生産性等の面からＴダイを用いる押出キャスト法が好適に用いられる。Ｔダイを用いる押出キャスト法での成形温度は、用いる樹脂組成物の流動特性や製膜性等によって適宜調整されるが、概ね１３０～３００℃、好ましくは、１５０～２５０℃である。シランカップリング剤、酸化防止剤、紫外線吸収剤、耐候安定剤等の各種添加剤は、予め樹脂とともにドライブレンドしてからホッパーに供給しても良いし、予め全ての材料を溶融混合してペレットを作製してから供給しても良いし、添加剤のみを予め樹脂に濃縮したマスターバッチを作製し供給してもかまわない。 As a method for forming the weathering layer (A), moisture-proof layer (B), flexible layer (C) and sealing material (D) used in the present invention, known methods such as a single screw extruder and a multi-screw extruder are used. It has melt mixing equipment such as a Banbury mixer and a kneader, and can adopt an extrusion casting method using a T-die or a calendar method, and is not particularly limited. From the viewpoint of properties and the like, an extrusion casting method using a T die is preferably used. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film-forming properties of the resin composition to be used, but is generally 130 to 300 ° C., preferably 150 to 250 ° C. Various additives such as silane coupling agents, antioxidants, UV absorbers, and weathering stabilizers may be dry blended with the resin in advance and then supplied to the hopper. The master batch may be supplied after being prepared, or a master batch in which only the additive is previously concentrated in the resin may be prepared and supplied.
　本発明の太陽電池用前面保護シートの厚みは、特に限定されるものではないが、通常、０．０５～１ｍｍ程度であり、好ましくは０．１～０．７ｍｍのシート状で用いられる。
本発明の太陽電池用前面保護シートは、上述の製膜された耐候層（Ａ）、防湿層（Ｂ）及び柔軟層（Ｃ）を、常法に従って、真空ラミネーターで温度１２０～１５０℃、脱気時間２～１５分、プレス圧力０．５～１ａｔｍ、プレス時間８～４５分で加熱加圧圧着することにより製造することができる。 The thickness of the front protective sheet for solar cells of the present invention is not particularly limited, but is usually about 0.05 to 1 mm, preferably 0.1 to 0.7 mm.
The front protective sheet for a solar cell of the present invention is formed by removing the film-formed weatherable layer (A), moisture-proof layer (B) and flexible layer (C) with a vacuum laminator at a temperature of 120 to 150 ° C. according to a conventional method. It can be produced by heat-pressure bonding with a gas time of 2 to 15 minutes, a press pressure of 0.5 to 1 atm, and a press time of 8 to 45 minutes.
　また、前面保護シート・封止材積層体の厚みは、特に限定されるものではないが、通常、０.１２～２.３ｍｍ程度であり、好ましくは０.３～１.６ｍｍ程度あり，より好ましくは０.６０～１.２ｍｍ程度のシート状で用いられる。
　前面保護シート・封止材積層体は、上述の製膜された耐候層（Ａ）、柔軟層（Ｂ）、防湿層（Ｃ）及び封止材（Ｄ）を、定法に従って、真空ラミネーターで温度１２０～１７０℃、脱気時間２～１５分、プレス圧力０．５～１ａｔｍ、プレス時間８～４５分で加熱加圧圧着することにより製造することができる。 The thickness of the front protective sheet / sealing material laminate is not particularly limited, but is usually about 0.12 to 2.3 mm, preferably about 0.3 to 1.6 mm. Preferably, it is used in the form of a sheet of about 0.60 to 1.2 mm.
The front protective sheet / sealing material laminate is prepared by subjecting the above-mentioned weathered layer (A), flexible layer (B), moisture-proof layer (C) and sealing material (D) to a temperature by a vacuum laminator according to a conventional method. It can be produced by heat and pressure bonding at 120 to 170 ° C., a degassing time of 2 to 15 minutes, a pressing pressure of 0.5 to 1 atm, and a pressing time of 8 to 45 minutes.
　なお、本発明においては、本発明の前面保護シートは、耐候層（Ａ）をその表面側として、また防湿層（Ｂ）をその内面側として、すなわち、前面（上部）から、耐候層（Ａ）、柔軟層（Ｃ）、防湿層（Ｂ）の順に配置されるのが好ましく、前面保護シート・封止材積層体は、前面（上部）から、耐候層（Ａ）、柔軟層（Ｃ）、防湿層（Ｂ）、封止材（Ｄ）の順に配置されるのが好ましい。本発明においては、このような構成により、防湿層の劣化を防止し、長期の高い防湿性と耐候性を達成することができる。
　図１に示す太陽電池用前面保護シートの例は、耐候層１と防湿層２とを柔軟層３を介して積層し、接着一体化したものである。 In the present invention, the front protective sheet of the present invention has the weather resistant layer (A) as its surface side and the moisture proof layer (B) as its inner surface side, that is, from the front surface (upper part), the weather resistant layer (A ), Flexible layer (C), and moisture-proof layer (B) are preferably arranged in this order, and the front protective sheet / sealing material laminate is formed from the front surface (upper part), the weather resistant layer (A), and the flexible layer (C). The moisture-proof layer (B) and the sealing material (D) are preferably arranged in this order. In the present invention, with such a configuration, it is possible to prevent the moisture-proof layer from deteriorating and achieve long-term high moisture resistance and weather resistance.
The example of the front protective sheet for a solar cell shown in FIG. 1 is obtained by laminating a weather-resistant layer 1 and a moisture-proof layer 2 via a flexible layer 3 and bonding them together.
　本発明の太陽電池用前面保護シート・封止材積層体は、耐候層（Ａ）、柔軟層（Ｃ）及び防湿層（Ｂ）を形成した後にシート状の封止材（Ｄ）と積層してもよいが、耐候層（Ａ）、柔軟層（Ｃ）、防湿層（Ｂ）とシート状の封止材（Ｄ）とを積層してもよい。
　図２に示す太陽電池用前面保護シート・封止材積層体の例は、耐候層１、柔軟層３，防湿層２及び封止樹脂層４を積層し、積層一体化したものである。
　本発明の太陽電池用前面保護シート・封止材積層体は、上記の構成を有するものであるが、前面保護シートと封止材を一体化するとともに、特に、防湿層（Ｂ）を上記の柔軟層（Ｃ）とシート状の封止材（Ｄ）の間に配置することにより、高い光線透過率を達成しかつ防湿性の低下を著しく低減することが可能となる。 The solar cell front protective sheet / sealing material laminate of the present invention is laminated with a sheet-like sealing material (D) after forming a weather-resistant layer (A), a flexible layer (C) and a moisture-proof layer (B). However, you may laminate | stack a weather-resistant layer (A), a flexible layer (C), a moisture-proof layer (B), and a sheet-like sealing material (D).
The example of the solar cell front protective sheet / sealing material laminate shown in FIG. 2 is obtained by laminating a weather-resistant layer 1, a flexible layer 3, a moisture-proof layer 2, and a sealing resin layer 4.
The solar cell front protective sheet / sealing material laminate according to the present invention has the above-described configuration. In addition to integrating the front protective sheet and the sealing material, in particular, the moisture-proof layer (B) is provided as described above. By arrange | positioning between a flexible layer (C) and a sheet-like sealing material (D), it becomes possible to achieve a high light transmittance and to reduce a moisture-proof fall remarkably.
　本発明における太陽電池用前面保護シートおよび太陽電池用前面保護シート・封止材積層体は、いずれも透明性が高いことが好ましく、その全光線透過率は、適用する太陽電池の種類、例えばアモルファスの薄膜系シリコン型などや太陽電子素子に届く太陽光を遮らない部位に適用する場合には、あまり重視されないこともあるが、太陽電池の光電変換効率や各種部材を重ね合わせる時のハンドリング性などを考慮し、８４％以上であることが好ましく、８５％以上であることがさらに好ましい。全光線透過率は、後述するように、ＪＩＳ Ｋ７１０５に準じて測定することができる。 The solar cell front protective sheet and the solar cell front protective sheet / sealing material laminate in the present invention preferably both have high transparency, and the total light transmittance is the type of solar cell to be applied, for example, amorphous. When applied to parts that do not block the sunlight that reaches the solar electronic elements, such as thin film silicon types, there are things that are not very important, but the photoelectric conversion efficiency of solar cells and handling properties when overlaying various members, etc. In view of the above, it is preferably 84% or more, and more preferably 85% or more. The total light transmittance can be measured according to JIS K7105 as described later.
　また、太陽電池用前面保護シートおよび太陽電池用前面保護シート・封止材積層体の防湿性能については、該前面保護シートの構成、特に、柔軟性と耐熱性および透明性とが良好にバランスされた柔軟層（Ｃ）を防湿層（Ｂ）の外側（前面）に設けることにより、また、前面保護シート・封止材積層体の構成、特に、上記柔軟層（Ｃ）を防湿層（Ｂ）の外側（前面）に設け、更に防湿層（Ｂ）を柔軟層（Ｃ）と封止材（Ｄ）の間に配置することにより、前面保護シートの柔軟性の確保により防湿層の劣化を防止し、長期の高い防湿性と耐候性を達成することができる。防湿性能はＪＩＳ Ｚ０２２２「防湿包装容器の透湿度試験方法」、ＪＩＳ Ｚ０２０８「防湿包装材量の透湿度試験方法（カップ法）」の諸条件に準じ、具体的には後述の方法で評価することができる。 In addition, regarding the moisture-proof performance of the solar cell front protective sheet and solar cell front protective sheet / sealing material laminate, the configuration of the front protective sheet, in particular, flexibility, heat resistance and transparency are well balanced. By providing the flexible layer (C) on the outer side (front surface) of the moisture-proof layer (B), the structure of the front protective sheet / sealing material laminate, in particular, the flexible layer (C) is used as the moisture-proof layer (B). By providing a moisture-proof layer (B) between the flexible layer (C) and the sealing material (D), it is possible to prevent deterioration of the moisture-proof layer by ensuring the flexibility of the front protective sheet. In addition, long-term high moisture resistance and weather resistance can be achieved. The moisture-proof performance is evaluated according to the conditions of JIS Z0222 “Moisture permeability test method for moisture-proof packaging containers” and JIS Z0208 “Moisture permeability test method for moisture-proof packaging materials (cup method)”, and specifically evaluated by the method described below. Can do.
＜太陽電池モジュール、太陽電池の製造方法＞
　このような太陽電池用前面保護シートまたは前面保護シート・封止材積層体を用いて本発明の太陽電池モジュール及び／又は太陽電池を製造するには、従来の太陽電池のガラス板の代りに本発明の前面保護シートを用いて公知の方法により、作製すれば良い。 <Solar cell module, solar cell manufacturing method>
In order to manufacture the solar cell module and / or solar cell of the present invention using such a front protective sheet for solar cells or a front protective sheet / sealant laminate, the present solar cell module is replaced with a conventional solar cell glass plate. What is necessary is just to produce by the well-known method using the front surface protection sheet of invention.
　本発明の太陽電池用前面保護シートまたは前面保護シート・封止材積層体を用い、太陽電池素子をバックシートとともに固定することにより太陽電池モジュールを製作することができる。このような太陽電池モジュールとしては、種々のタイプのものを例示することができ、本発明の太陽電池用前面保護シートを用いる場合は、好ましくは、本発明の太陽電池用前面保護シートと、封止材と、太陽電池素子と、下部保護材とを用いて作製された太陽電池モジュールが挙げられ、具体的には、上部保護材（本発明の太陽電池用前面保護シート）／封止材（封止樹脂層）／太陽電池素子／封止材（封止樹脂層）／下部保護材の構成のもの（図３参照）、下部保護材の内周面上に形成させた太陽電池素子上に封止材と上部保護材（本発明の太陽電池用前面保護シート）を形成させるような構成のもの、上部保護材（本発明の太陽電池用前面保護シート）の内周面上に形成させた太陽電池素子、例えばフッ素樹脂系透明保護材上にアモルファス太陽電池素子をスパッタリング等で作製したものの上に封止材と下部保護材を形成させるような構成のものなどを挙げることができる。 The solar cell module can be manufactured by fixing the solar cell element together with the back sheet using the front protective sheet for solar cells or the front protective sheet / sealing material laminate of the present invention. As such a solar cell module, various types can be exemplified. When the solar cell front protective sheet of the present invention is used, preferably, the solar cell front protective sheet of the present invention and the sealing are used. A solar cell module manufactured using a stopper, a solar cell element, and a lower protective material is mentioned. Specifically, an upper protective material (front protective sheet for solar cell of the present invention) / sealing material ( Sealing resin layer) / solar cell element / sealing material (sealing resin layer) / lower protective material (see FIG. 3), on the solar cell element formed on the inner peripheral surface of the lower protective material A structure in which a sealing material and an upper protective material (front protective sheet for solar cell of the present invention) are formed, and formed on the inner peripheral surface of the upper protective material (front protective sheet for solar cell of the present invention). Amorphous on a solar cell element such as a fluororesin transparent protective material And the like § scan solar cell element having a configuration such as to form a sealing material and a lower protective material on top of those made by sputtering or the like.
　また、本発明の前面保護シート・封止材積層体を用いる場合は、好ましくは、本発明の太陽電池用前面保護シート・封止材積層体と、太陽電池素子と、下部保護材とを用いて作製された太陽電池モジュールが挙げられ、具体的には、本発明の太陽電池用前面保護シート・封止材積層体／太陽電池素子／封止材（封止樹脂層）／下部保護材の構成のもの（図３参照）、下部保護材の内周面上に形成させた太陽電池素子上に本発明の太陽電池用前面保護シート・封止材積層体を形成させるような構成のもの、本発明の太陽電池用前面保護シート・封止材積層体の内周面上に形成させた太陽電池素子、例えばフッ素樹脂系透明保護材上にアモルファス太陽電池素子をスパッタリング等で作製したものの上に封止材と下部保護材を形成させるような構成のものなどを挙げることができる。 Moreover, when using the front surface protection sheet / sealing material laminate of the present invention, preferably, the front surface protection sheet / sealing material layered body for solar cells, the solar cell element, and the lower protection material of the present invention are used. Specifically, the solar cell module produced by the above method can be used. Specifically, the solar cell front protective sheet / sealing material laminate / solar cell element / sealing material (sealing resin layer) / lower protective material of the present invention. A structure (see FIG. 3), a structure in which the solar cell front protective sheet / sealing material laminate of the present invention is formed on the solar cell element formed on the inner peripheral surface of the lower protective material, On the solar cell element formed on the inner peripheral surface of the solar cell front protective sheet / sealing material laminate of the present invention, for example, an amorphous solar cell element produced by sputtering or the like on a fluororesin-based transparent protective material Such as forming a sealant and lower protective material Or the like can be mentioned the formation.
　太陽電池素子としては、例えば、単結晶シリコン型、多結晶シリコン型、アモルファスシリコン型、ガリウム－砒素、銅－インジウム－セレン、カドミウム－テルルなどのＩＩＩ－Ｖ族やＩＩ－ＶＩ族化合物半導体型、色素増感型、有機薄膜型等が挙げられる。 Examples of solar cell elements include single crystal silicon type, polycrystalline silicon type, amorphous silicon type, III-V group and II-VI group compound semiconductor types such as gallium-arsenic, copper-indium-selenium, cadmium-tellurium, Examples include a dye sensitizing type and an organic thin film type.
　本発明の太陽電池用前面保護シートまたは前面保護シート・封止材積層体を用いて作製された太陽電池モジュールを構成する各部材については、特に限定されるものではないが、封止材としては、例えば、エチレン－ 酢酸ビニル共重合体を挙げることもできるが、前記封止材（Ｄ）を使用することが好ましい。封止材は、前面保護シートへの密着性確保の観点から、その少なくとも一方の面にコロナ処理等の表面処理を施すことが好ましい。
下部保護材としては、金属や各種熱可塑性樹脂層などの単層もしくは多層のシートであり、例えば、錫、アルミ、ステンレスなどの金属、ガラス等の無機材料、ポリエステル、無機物蒸着ポリエステル、フッ素含有樹脂、ポリオレフィンなどの単層もしくは多層の保護材を挙げることができる。上部および／又は下部の保護材の表面には、封止材や他の部材との接着性を向上させるためにプライマー処理やコロナ処理など公知の表面処理を施すことができる。 About each member which comprises the solar cell module produced using the front surface protection sheet for solar cells of this invention or a front surface protection sheet and a sealing material laminated body, although it does not specifically limit, As a sealing material, For example, an ethylene-vinyl acetate copolymer may be mentioned, but it is preferable to use the sealing material (D). The sealing material is preferably subjected to surface treatment such as corona treatment on at least one surface thereof from the viewpoint of ensuring adhesion to the front protective sheet.
The lower protective material is a single layer or multilayer sheet such as a metal or various thermoplastic resin layers, for example, a metal such as tin, aluminum or stainless steel, an inorganic material such as glass, a polyester, an inorganic vapor deposition polyester, a fluorine-containing resin. And a single-layer or multilayer protective material such as polyolefin. The surface of the upper and / or lower protective material can be subjected to a known surface treatment such as a primer treatment or a corona treatment in order to improve the adhesion to the sealing material or other members.
　本発明の太陽電池用前面保護シートまたは前面保護シート・封止材積層体を用いて作製された太陽電池モジュールを既述した上部保護材／封止材／太陽電池素子／封止材／下部保護材のような構成のものを例として説明する。図３に示すように、太陽光受光側から順に、本発明の太陽電池用前面保護シート１０、封止樹脂層１２Ａ、太陽電池素子１４Ａ，１４Ｂ、封止樹脂層１２Ｂ、バックシート１６が積層されてなり、さらに、バックシート１６の下面にジャンクションボックス１８（太陽電池素子から発電した電気を外部へ取り出すための配線を接続する端子ボックス）が接着されてなる。太陽電池素子１４Ａ及び１４Ｂは、発電電流を外部へ電導するために配線２０により連結されている。配線２０は、バックシート１６に設けられた貫通孔（不図示）を通じて外部へ取り出され、ジャンクションボックス１８に接続されている。 The upper protective material / encapsulant / solar cell element / encapsulant / lower protection described above for the solar cell module produced using the front protective sheet for solar cells or the front protective sheet / encapsulant laminate of the present invention An example of a material-like structure will be described. As shown in FIG. 3, the solar cell front protective sheet 10, the sealing resin layer 12A, the solar cell elements 14A and 14B, the sealing resin layer 12B, and the back sheet 16 are laminated in order from the sunlight receiving side. Further, a junction box 18 (a terminal box for connecting wiring for taking out the electricity generated from the solar cell element) is bonded to the lower surface of the back sheet 16. The solar cell elements 14A and 14B are connected by a wiring 20 in order to conduct the generated current to the outside. The wiring 20 is taken out through a through hole (not shown) provided in the back sheet 16 and connected to the junction box 18.
　太陽電池モジュールの製造方法としては、公知の製造方法が適用でき、特に限定されるものではないが、一般的には、前面保護シート、封止樹脂層、太陽電池素子、封止樹脂層、下部保護材の順に積層する工程と、それらを真空吸引し加熱圧着する工程を有する。また、バッチ式の製造設備やロール・ツー・ロール式の製造設備なども適用することができる。 As a manufacturing method of the solar cell module, a known manufacturing method can be applied, and is not particularly limited, but generally, a front protective sheet, a sealing resin layer, a solar cell element, a sealing resin layer, a lower part It has the process of laminating | stacking a protective material in order, and the process of vacuum-sucking them and carrying out thermocompression bonding. Also, batch type manufacturing equipment, roll-to-roll type manufacturing equipment, and the like can be applied.
　本発明の太陽電池用前面保護シートまたは前面保護シート・封止材積層体を用いて作製された太陽電池モジュールは、適用される太陽電池のタイプとモジュール形状により、モバイル機器に代表される小型太陽電池、屋根や屋上に設置される大型太陽電池など屋内、屋外に関わらず各種用途に適用することができる。 The solar cell module produced by using the front protective sheet for solar cells or the front protective sheet / sealing material laminate of the present invention is a small solar cell typified by a mobile device depending on the type of solar cell applied and the module shape. It can be applied to various uses regardless of whether it is indoors or outdoors, such as batteries and large solar cells installed on the roof or rooftop.
　本発明の太陽電池モジュール及び／又は太陽電池は、この太陽電池用保護シート，封止材，発電素子，封止材，裏面保護シートを、常法に従って、真空ラミネーターで温度１２０～１５０℃、脱気時間２～１５分、プレス圧力０．５～１ａｔｍ、プレス時間８～４５分で加熱加圧圧着することにより容易に製造することができる。 In the solar cell module and / or solar cell of the present invention, this solar cell protective sheet, encapsulant, power generation element, encapsulant, and back surface protective sheet are removed at a temperature of 120 to 150 ° C. with a vacuum laminator according to a conventional method. Manufacture can be easily performed by heat-pressure bonding with a gas time of 2 to 15 minutes, a press pressure of 0.5 to 1 atm, and a press time of 8 to 45 minutes.
　以下に、本発明を実施例によりさらに具体的に説明するが、これらの実施例及び比較例により本発明は何ら制限を受けるものではない。なお、本明細書中に表示されるシートについての種々の測定値および評価は次のようにして行った。 Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples and comparative examples. In addition, the various measured values and evaluation about the sheet | seat displayed in this specification were performed as follows.
（物性測定）
（１）結晶融解ピーク温度（Ｔｍ）
　（株）パーキンエルマー製の示差走査熱量計、商品名「Ｐｙｒｉｓ１ ＤＳＣ」を用いて、ＪＩＳ Ｋ７１２１に準じて、試料約１０ｍｇを加熱速度１０℃／分で－４０℃から２００℃まで昇温し、２００℃で５分間保持した後、冷却速度１０℃／分で－４０℃まで降温し、再度、加熱速度１０℃／分で２００℃まで昇温した時に測定されたサーモグラムから結晶融解ピーク温度（Ｔｍ）（℃）を求めた。 (Physical property measurement)
(1) Crystal melting peak temperature (Tm)
Using a differential scanning calorimeter manufactured by PerkinElmer Co., Ltd., trade name “Pyris1 DSC”, according to JIS K7121, about 10 mg of the sample was heated from −40 ° C. to 200 ° C. at a heating rate of 10 ° C./min. After holding at 200 ° C. for 5 minutes, the temperature was lowered to −40 ° C. at a cooling rate of 10 ° C./min, and again from the thermogram measured when the temperature was raised to 200 ° C. at a heating rate of 10 ° C./min ( Tm) (° C.) was determined.
（２）結晶融解熱量（ΔＨｍ）
　（株）パーキンエルマー製の示差走査熱量計、商品名「Ｐｙｒｉｓ１ ＤＳＣ」を用いて、ＪＩＳ Ｋ７１２２に準じて、試料約１０ｍｇを加熱速度１０℃／分で－４０℃から２００℃まで昇温し、２００℃で５分間保持した後、冷却速度１０℃／分で－４０℃まで降温し、再度、加熱速度１０℃／分で２００℃まで昇温した時に測定されたサーモグラムから結晶融解熱量（ΔＨｍ）（Ｊ／ｇ）を求めた。 (2) Heat of crystal melting (ΔHm)
Using a differential scanning calorimeter manufactured by PerkinElmer Co., Ltd., trade name “Pyris1 DSC”, according to JIS K7122, about 10 mg of the sample was heated from −40 ° C. to 200 ° C. at a heating rate of 10 ° C./min. After holding at 200 ° C. for 5 minutes, the temperature was lowered to −40 ° C. at a cooling rate of 10 ° C./min, and again from the thermogram measured when the temperature was raised to 200 ° C. at a heating rate of 10 ° C./min (ΔHm ) (J / g).
（３）貯蔵弾性率測定
　アイティ計測（株）製の粘弾性測定装置、商品名「粘弾性スペクトロメーターＤＶＡ－２００」を用いて、試料（縦４ｍｍ、横６０ｍｍ）を振動周波数１０Ｈｚ、ひずみ０．１％、昇温速度３℃／分、チャック間２５ｍｍで横方向について、－１５０℃から１５０℃まで測定し、得られたデータから２０℃における貯蔵弾性率（Ｅ´）（ＭＰａ）を求めた。 (3) Storage elastic modulus measurement Using a viscoelasticity measuring apparatus manufactured by IT Measurement Co., Ltd., trade name “Viscoelasticity Spectrometer DVA-200”, a sample (4 mm long, 60 mm wide) was subjected to vibration frequency 10 Hz, strain 0. Measurement was made from −150 ° C. to 150 ° C. in the transverse direction at a rate of 1%, a heating rate of 3 ° C./min, and a chuck spacing of 25 mm, and the storage modulus (E ′) (MPa) at 20 ° C. was determined from the obtained data .
（４）全光線透過率
　厚み３ｍｍの白板ガラス（サイズ；縦７５ｍｍ、横２５ｍｍ）２枚の間に耐候層，各柔軟層、防湿層を重ね、真空プレス機を用いて、１５０℃、１５分の条件で積層プレスした試料を作製し、ＪＩＳ Ｋ７１０５に準じて全光線透過率を測定し、その値を記載するとともに、下記の基準で評価した結果も併記した。
（◎）全光線透過率が９０％以上
（○）全光線透過率が８５％以上、９０％未満
（×）全光線透過率が８５％未満、あるいは、明らかに白濁している場合（未測定） (4) Total light transmittance The weatherproof layer, each flexible layer, and the moisture-proof layer are stacked between two pieces of white plate glass (size: length 75 mm, width 25 mm) having a thickness of 3 mm, and 150 ° C. for 15 minutes using a vacuum press machine. A sample that was laminated and pressed under the above conditions was prepared, the total light transmittance was measured according to JIS K7105, the value was described, and the results evaluated according to the following criteria were also shown.
(◎) Total light transmittance is 90% or more (○) Total light transmittance is 85% or more and less than 90% (×) Total light transmittance is less than 85% or clearly cloudy (not measured) )
（５）耐熱性
　厚み３ｍｍの白板ガラス（サイズ；縦７５ｍｍ、横２５ｍｍ）２枚の間に柔軟層を重ね、真空プレス機を用いて、１５０℃、１５分の条件で積層プレスした試料を作製し、該試料を１００℃の恒温槽内で６０度に傾斜して設置し５００時間経過後の状態を観察し、下記の基準で評価した。
（○）ガラスが初期の基準位置からずれなかったもの
（×）ガラスが初期の基準位置からずれたり、シートが溶融したもの (5) Heat resistance A flexible layer is layered between two pieces of 3 mm thick white sheet glass (size: length 75 mm, width 25 mm), and a sample that is laminated and pressed using a vacuum press machine at 150 ° C. for 15 minutes is prepared. The sample was installed at an inclination of 60 degrees in a constant temperature bath at 100 ° C., the state after 500 hours was observed, and evaluated according to the following criteria.
(○) The glass did not deviate from the initial reference position (×) The glass deviated from the initial reference position or the sheet melted
（６）防湿性能
　防湿性能はＪＩＳ Ｚ０２２２「防湿包装容器の透湿度試験方法」、ＪＩＳ Ｚ０２０８「防湿包装材量の透湿度試験方法（カップ法）」の諸条件に準じ、次の手法で評価することができる。
　透湿面積１０．０ｃｍ×１０．０ｃｍ角の各積層フィルム又は積層体を２枚用い、吸湿剤として無水塩化カルシウム約２０ｇを入れ四辺を封じた袋を作製し、その袋を温度４０℃相対湿度９０％の恒温恒湿装置に入れ、４８時間以上間隔で質量増加がほぼ一定になる目安として１４日間まで、質量測定（０．１ｍｇ単位）し、水蒸気透過率を下記式から算出する。
  水蒸気透過率（ｇ／ｍ2／２４ｈ）＝（ｍ／ｓ）／ｔ
    ｍ； 試験期間最後２回の秤量間隔の増加質量（ｇ）
    ｓ； 透湿面積（ｍ2）
    ｔ； 試験期間最後２回の秤量間隔の時間（ｈ）／２４（ｈ） (6) Moisture-proof performance The moisture-proof performance is evaluated by the following method according to the conditions of JIS Z0222 “Test method for moisture permeability of moisture-proof packaging containers” and JIS Z0208 “Test method for moisture permeability of amount of moisture-proof packaging material (cup method)”. be able to.
Using two laminated films or laminates each having a moisture permeable area of 10.0 cm x 10.0 cm square, a bag containing about 20 g of anhydrous calcium chloride as a hygroscopic agent and sealed on all sides is produced. In a 90% constant temperature and humidity device, mass measurement (0.1 mg unit) is performed for up to 14 days as a guideline that the mass increase becomes almost constant at intervals of 48 hours or more, and the water vapor transmission rate is calculated from the following formula.
Water vapor transmission rate (g / m 2 / 24h) = (m / s) / t
m: Mass increase in the last two weighing intervals (g)
s; Moisture permeable area (m 2 )
t: Time of last two weighing intervals (h) / 24 (h)
（７）防湿保持性（バリア安定性）
　耐候層，柔軟層，防湿層，封止樹脂層を株式会社エヌ・ピー・シー社製真空ラミネート装置ＬＭ－３０ｘ３０を用い１５０℃，１５分の条件で定法により積層し前面保護シート封止材積層品を作製した。その後、作製した前面保護シート封止材積層品の水蒸気透過率と、下記構成フィルム(２)の防湿層の水蒸気透過率を、それぞれ上記ＪＩＳ Ｚ０２０８「防湿包装材量の透湿度試験方法（カップ法）」に準じて評価し、防湿性能を求めた。下記構成フィルム(２)の防湿層の防湿性能に対する、得られた積層体の防湿性能の低下度が５０％以内を◎、５０％超１００％以内を○、１００％超を×として評価した。 (7) Moisture retention (barrier stability)
Laminated weather-proof layer, flexible layer, moisture-proof layer and sealing resin layer using a vacuum laminator LM-30x30 manufactured by NPC Corporation at 150 ° C for 15 minutes and laminated the front protective sheet sealing material An article was made. Then, the water vapor transmission rate of the produced front protective sheet sealing material laminate and the water vapor transmission rate of the moisture-proof layer of the following constituent film (2) were respectively measured according to the above-mentioned JIS Z0208 “Moisture permeability test method for moisture-proof packaging material amount (cup method ) "And evaluated moisture-proof performance. With respect to the moisture proof performance of the moisture proof layer of the following constituent film (2), the degree of decrease in the moisture proof performance of the obtained laminate was evaluated as ◎, within 50%, ◯ over 50% and 100%, and x over 100%.
（構成層）
（１）耐候層
　旭硝子社製ＥＴＦＥ　５０μを使用した，本ＥＴＦＥの全光線透過率は９５％であった。 (Component layer)
(1) Weatherproof layer The total light transmittance of this ETFE using Asahi Glass Co., Ltd. ETFE 50μ was 95%.
（２）防湿層
　１２μｍポリエチレンテレフタレート樹脂フィルムにシリカを蒸着した三菱樹脂製テックバリアＬＸを使用した。本防湿層の全光線透過率は８６％であった。また上述の方法で測定した防湿性は０.２［ｇ／（ｍ2・ｄａｙ）］であった。 (2) Moisture-proof layer Mitsubishi Plastics Tech Barrier LX in which silica was vapor-deposited on a 12 μm polyethylene terephthalate resin film was used. The total light transmittance of this moisture barrier layer was 86%. Further, the moisture resistance measured by the above-described method was 0.2 [g / (m 2 · day)].
（３）柔軟層1
　エチレン－α－オレフィンランダム共重合体（Ｃ－１）として、エチレン－オクテンランダム共重合体（ダウ・ケミカル（株）製、商品名：エンゲージ（ＥＮＧＡＧＥ）８２００、オクテン含有量：７．３モル％（２４質量％）、ＭＦＲ：５、Ｔｍ：６５℃、ΔＨｍ：５３Ｊ／ｇ）（以下、α－１と略する）を９５質量部とエチレン－α－オレフィンブロック共重合体（Ｃ－２）として、エチレン－オクテンブロック共重合体（ダウ・ケミカル（株）製、商品名：インフューズ（ＩＮＦＵＳＥ）Ｄ９１００．０５、オクテン含有量：１２．８モル％（３７質量％）、ＭＦＲ：１、Ｔｍ：１１９℃、ΔＨｍ：３８Ｊ／ｇ）（以下、β－１と略する）とを５質量部の割合で混合した樹脂組成物をＴダイを備えた４０ｍｍφ 単軸押出機を用いて設定温度２００℃で溶融混練し、２０℃のキャストロールで急冷製膜することにより厚みが０．５ｍｍの柔軟層１を得た。 (3) Flexible layer 1
As the ethylene-α-olefin random copolymer (C-1), ethylene-octene random copolymer (manufactured by Dow Chemical Co., Ltd., trade name: ENGAGE 8200, octene content: 7.3 mol%) (24 mass%), MFR: 5, Tm: 65 ° C., ΔHm: 53 J / g) (hereinafter abbreviated as α-1) and 95 parts by mass of ethylene-α-olefin block copolymer (C-2) As an ethylene-octene block copolymer (manufactured by Dow Chemical Co., Ltd., trade name: INFUSE D9100.05, octene content: 12.8 mol% (37 mass%), MFR: 1, Tm 119 ° C., ΔHm: 38 J / g) (hereinafter abbreviated as β-1) at a ratio of 5 parts by mass, a set temperature using a 40 mmφ single screw extruder equipped with a T die 00 was melt-kneaded at ° C., thickness to obtain a flexible layer 1 of 0.5mm by quenching casting at 20 ° C. of cast rolls.
（４）柔軟層２
　柔軟層1の調製において、シートを構成する樹脂組成物を表１に示すように、（α－１）８０質量部とエチレン－オクテンブロック共重合体（ダウ・ケミカル（株）製、商品名：インフューズＤ９５０７．１５、オクテン含有量：１６．４モル％（４４質量％）、ＭＦＲ：５、Ｔｍ：１２３℃、ΔＨｍ：２１Ｊ／ｇ）（以下、β－２と略する）２０質量部との樹脂組成物に変更した以外は、柔軟層１と同様にして、厚みが０．５ｍｍの柔軟層２を得た (4) Flexible layer 2
In the preparation of the flexible layer 1, as shown in Table 1, the resin composition constituting the sheet is 80 parts by mass of (α-1) and an ethylene-octene block copolymer (manufactured by Dow Chemical Co., Ltd., trade name: Infuse D9507.15, Octene content: 16.4 mol% (44 mass%), MFR: 5, Tm: 123 ° C., ΔHm: 21 J / g) (hereinafter abbreviated as β-2) 20 mass parts A flexible layer 2 having a thickness of 0.5 mm was obtained in the same manner as the flexible layer 1 except that the resin composition was changed to
（５）柔軟層３
　柔軟層１の調製において、シートを構成する樹脂組成物を表１に示すように、（α－１）をエチレン－プロピレン－ヘキセン３元ランダム共重合体（日本ポリエチレン（株）製、商品名：カーネル（Ｋａｒｎｅｌ）ＫＪ６４０Ｔ、プロピレン含有量：７．４モル％（１０質量％）、ヘキセン含有量：４．４モル％（１０質量％）、ＭＦＲ：３０、Ｔｍ：５３℃、ΔＨｍ：５８Ｊ／ｇ）（以下、α－２と略する）に変更した以外は、柔軟層１と同様にして、厚みが０．５ｍｍの柔軟層３を得た。 (5) Flexible layer 3
In the preparation of the flexible layer 1, as shown in Table 1, the resin composition constituting the sheet is represented by (α-1) is an ethylene-propylene-hexene ternary random copolymer (manufactured by Nippon Polyethylene Co., Ltd., trade name: Kernel KJ640T, propylene content: 7.4 mol% (10 wt%), hexene content: 4.4 mol% (10 wt%), MFR: 30, Tm: 53 ° C., ΔHm: 58 J / g The flexible layer 3 having a thickness of 0.5 mm was obtained in the same manner as the flexible layer 1 except that the thickness was changed to (hereinafter abbreviated as α-2).
（６）柔軟層４
　柔軟層１の調製において、シートを構成する樹脂組成物を表１に示すように、（α－１）１００質量部に変更した以外は、実施例１と同様にして、厚みが０．５ｍｍの柔軟層４を得た。 (6) Flexible layer 4
In the preparation of the flexible layer 1, the resin composition constituting the sheet was changed to 100 parts by mass of (α-1) as shown in Table 1, and the thickness was 0.5 mm as in Example 1. A flexible layer 4 was obtained.
（７）柔軟層５
　柔軟層1の調製において、シートを構成する樹脂組成物を表１に示すように、（β－１）を汎用の結晶性ポリエチレン樹脂であるエチレン－オクテンランダム共重合体（（株）プライムポリマー製、商品名：モアテック０２３８ＣＮ、オクテン含有量：１モル％（４質量％）、ＭＦＲ：２．１、Ｔｍ：１２１℃、ΔＨｍ：１２７Ｊ／ｇ）（以下、Ｐ－１と略する）に変更した以外は、柔軟層１と同様にして、厚みが０．５ｍｍの柔軟層５を得た。 (7) Flexible layer 5
In the preparation of the flexible layer 1, as shown in Table 1, the resin composition constituting the sheet is an ethylene-octene random copolymer (manufactured by Prime Polymer Co., Ltd.), a general-purpose crystalline polyethylene resin. , Trade name: Moretech 0238CN, Octene content: 1 mol% (4 mass%), MFR: 2.1, Tm: 121 ° C., ΔHm: 127 J / g (hereinafter abbreviated as P-1) Except for the above, a flexible layer 5 having a thickness of 0.5 mm was obtained in the same manner as the flexible layer 1.
（８）柔軟層６
　柔軟層1の調製において、シートを構成する樹脂組成物を表１に示すように、（Ｐ－１）１００質量部に変更した以外は、柔軟層１と同様にして、厚みが０．５ｍｍの柔軟層６を得た。 (8) Flexible layer 6
In the preparation of the flexible layer 1, the resin composition constituting the sheet was changed to 100 parts by mass of (P-1) as shown in Table 1, and the thickness was 0.5 mm as in the flexible layer 1. A flexible layer 6 was obtained.
（９）柔軟層７
　Ｅｔｉｍｅｘ社製ＥＶＡ封止材４９６を用いた。なお，本ＥＶＡ封止材単体を下記実施例に示す方法で真空ラミネートし，その後，ＥＶＡ封止材のみを取り出し，全光線透過率を前記の方法で測定した。 (9) Flexible layer 7
An EVA sealant 496 manufactured by Etimex was used. In addition, this EVA sealing material single-piece | unit was vacuum-laminated by the method shown in the following Example, Then, only EVA sealing material was taken out and the total light transmittance was measured by the said method.
（１０）柔軟層８
　東洋インク製ウレタン系（ＰＵ）接着剤ＩＳ８０１と硬化剤ＣＲ００１を１０：１の比で配合し固形分塗工量１０ｇ／ｍ2となるようにシリコーン離型ＰＥＴフィルムに塗布し，４０℃，４日間養生した。その後，接着剤層のみを取り出し，全光線透過率を上記の方法で測定した。 (10) Flexible layer 8
Toyo Ink's urethane (PU) adhesive IS801 and curing agent CR001 were blended at a ratio of 10: 1 and applied to a silicone release PET film so that the solid content coating amount was 10 g / m 2. Cured for days. Thereafter, only the adhesive layer was taken out and the total light transmittance was measured by the above method.
（１１）柔軟層９
　柔軟層１の調製におけるα－１及びβ－１を用い、シートの厚みを０．３ｍｍに変更した以外は、柔軟層１と同様にして柔軟層９を得た。

　得られた柔軟層１～９の各々について、その厚み、組成及び全光線透過率、耐熱性及び柔軟性（貯蔵弾性率）を測定した結果を、以下の表１にまとめて示す。 (11) Flexible layer 9
A flexible layer 9 was obtained in the same manner as the flexible layer 1 except that α-1 and β-1 in the preparation of the flexible layer 1 were used and the thickness of the sheet was changed to 0.3 mm.

The results of measuring the thickness, composition, total light transmittance, heat resistance and flexibility (storage modulus) of each of the obtained flexible layers 1 to 9 are summarized in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
実施例１
　前記調製した耐候層，柔軟層１，防湿層を株式会社エヌ・ピー・シー社製真空ラミネート装置ＬＭ－３０ｘ３０を用い１５０℃，１５分の条件で定法により積層し前面保護シート1を作製した。その後、作製した前面保護シート１を使用して上記に示した柔軟層と同様の方法で全光線透過率を測定し、その結果を表２に示す。さらに、以下の方法で防湿性を測定したところ、その値は０．２４ｇ／（ｍ2・ｄａｙ）であった。 Example 1
The prepared weather-resistant layer, flexible layer 1 and moisture-proof layer were laminated by a conventional method at 150 ° C. for 15 minutes using a vacuum laminator LM-30x30 manufactured by NPC Co., Ltd. to prepare a front protective sheet 1. Then, the total light transmittance was measured by the method similar to the flexible layer shown above using the produced front surface protection sheet 1, and the result is shown in Table 2. Furthermore, when moisture resistance was measured by the following method, the value was 0.24 g / (m 2 · day).
実施例２
　耐候性層，柔軟層２，防湿層を実施例1と同様に真空ラミを行い積層し前面保護シート２を作製し同様に全光線透過率を測定した。その結果を表２に示す。また、実施例１と同様に防湿性を測定したところ、その値は０．２４ｇ／（ｍ2・ｄａｙ）であった。 Example 2
The weatherproof layer, the flexible layer 2 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce the front protective sheet 2 and the total light transmittance was measured in the same manner. The results are shown in Table 2. Moreover, when moisture-proof property was measured like Example 1, the value was 0.24 g / (m < 2 > * day).
実施例３
　耐候性層，柔軟層３，防湿層を実施例1と同様に真空ラミを行い積層し前面保護シート３を作製し全光線透過率を測定した。その結果を表２に示す。また、実施例１と同様に防湿性を測定したところ、その値は０．２１ｇ／（ｍ2・ｄａｙ）であった。 Example 3
The weatherproof layer, the flexible layer 3 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce the front protective sheet 3 and the total light transmittance was measured. The results are shown in Table 2. Moreover, when moisture-proof property was measured like Example 1, the value was 0.21 g / (m < 2 > * day).
比較例１
　耐候性層，柔軟層４，防湿層を実施例1と同様に真空ラミを行い積層し前面保護シート４を作製し全光線透過率を測定した。その結果を表２に示す。 Comparative Example 1
The weather resistant layer, the flexible layer 4 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce the front protective sheet 4 and the total light transmittance was measured. The results are shown in Table 2.
比較例２
　耐候性層，柔軟層５，防湿層を実施例1と同様に真空ラミを行い積層し前面保護シート５を作製し全光線透過率を測定した。その結果を表２に示す。 Comparative Example 2
The weather-resistant layer, the flexible layer 5 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce the front protective sheet 5 and the total light transmittance was measured. The results are shown in Table 2.
比較例３
　耐候性層，柔軟層６，防湿層を実施例1と同様に真空ラミを行い積層し前面保護シート６作製し全光線透過率を測定した。その結果を表２に示す。 Comparative Example 3
The weatherproof layer, the flexible layer 6 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to prepare the front protective sheet 6 and the total light transmittance was measured. The results are shown in Table 2.
比較例４
　耐候性層，柔軟層７，防湿層を実施例1と同様に真空ラミを行い積層し前面保護シート７作製し全光線透過率を測定した。その結果を表２に示す。 Comparative Example 4
The weatherproof layer, the flexible layer 7 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce a front protective sheet 7 and the total light transmittance was measured. The results are shown in Table 2.
比較例５
　耐候性層，柔軟層８，防湿層を実施例1と同様に真空ラミを行い積層し前面保護シート８を作製し全光線透過率を測定した。その結果を表２に示す。 Comparative Example 5
The weather-resistant layer, the flexible layer 8 and the moisture-proof layer were laminated by vacuum lamination in the same manner as in Example 1 to produce the front protective sheet 8 and the total light transmittance was measured. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
 　以上のようにして得られた本発明の前面保護シートは、高防湿性と耐候性を兼備し、透明性にも優れるものであった。
Figure JPOXMLDOC01-appb-T000002
 The front protective sheet of the present invention obtained as described above has both high moisture resistance and weather resistance and is excellent in transparency.
　表１及び表２から明らかなように、本発明の前面保護シートに用いられた柔軟層１～３は防湿層を保護するために必要な柔軟性と耐熱性および透明性との良好なバランスが図られた、十分な厚みを有したものであった。したがって、柔軟層１～３を用いて作製された実施例１～３の前面保護シートは、高防湿性と耐候性を兼備し、透明性にも優れるのみならず、その防湿層が、長期における高温・傾斜条件下での使用に耐え、落下物等からの衝撃からの保護が図られるものである。
　一方、柔軟層４，８は、耐熱性に劣り、高温下・傾斜条件で使用されることによれば、基準値からずれたりシートが溶融したりすることが明らかとなった。したがって、柔軟層４，８を用いて作製された比較例１，５の前面保護シートにおいては、柔軟層がその役割を果たしきれず、防湿層の保護が十分ではないと考えられる。すなわち、高温下・傾斜条件での使用が見込まれる太陽電池用部材の素材としては好ましくない。また、柔軟層５～７は、柔軟性（貯蔵弾性率）に劣り、防湿層層の保護が不十分であることが示された。したがって、柔軟層５～７を用いて作製された比較例２～４の前面保護シートにおいても、柔軟層がその役割を果たしきれず、防湿層の保護が十分ではないと考えられる。 As is apparent from Tables 1 and 2, the flexible layers 1 to 3 used in the front protective sheet of the present invention have a good balance between flexibility, heat resistance and transparency required for protecting the moisture-proof layer. As shown, it had a sufficient thickness. Therefore, the front protective sheets of Examples 1 to 3 produced using the flexible layers 1 to 3 have not only high moisture resistance and weather resistance, but also excellent transparency. It can withstand use under high temperature and inclined conditions, and can be protected from impact from falling objects.
On the other hand, the flexible layers 4 and 8 are inferior in heat resistance, and when used under high temperature / inclined conditions, it has been revealed that the flexible layers 4 and 8 are deviated from the reference value or the sheet is melted. Therefore, in the front protective sheets of Comparative Examples 1 and 5 produced using the flexible layers 4 and 8, the flexible layer cannot fulfill its role, and it is considered that the moisture-proof layer is not sufficiently protected. That is, it is not preferable as a material for a solar cell member that is expected to be used under high temperature and inclined conditions. In addition, the flexible layers 5 to 7 were inferior in flexibility (storage modulus), indicating that the moisture-proof layer was insufficiently protected. Therefore, also in the front protective sheets of Comparative Examples 2 to 4 produced using the flexible layers 5 to 7, it is considered that the flexible layer cannot fulfill its role and the moisture-proof layer is not sufficiently protected.
実施例４
　前記調製した耐候層、柔軟層１、防湿層及び柔軟層１を株式会社エヌ・ピー・シー社製真空ラミネート装置ＬＭ－３０ｘ３０を用い１５０℃，１５分の条件で定法によりこの順に積層し前面保護シート封止材積層品1を作製した。その後、作製した前面保護シート封止材積層品１を使用して、上記の方法で全光線透過率及び防湿保持性を測定した。結果を表３に示す。尚、表中の「ＥＴＦＥ」は、旭硝子製ＥＴＦＥを、「ＢＦ」は三菱樹脂製テックバリアＬＸを意味するものとする。 Example 4
The above-prepared weathering layer, flexible layer 1, moisture-proof layer and flexible layer 1 are laminated in this order by a conventional method at 150 ° C. for 15 minutes using a vacuum laminating machine LM-30x30 manufactured by NPC Corporation. A sheet sealing material laminate 1 was produced. Then, using the produced front protective sheet sealing material laminate 1, the total light transmittance and moisture proof retention were measured by the above methods. The results are shown in Table 3. In the table, “ETFE” means ETFE made by Asahi Glass and “BF” means Tech Barrier LX made by Mitsubishi Plastics.
実施例５
　耐候性層、柔軟層２、防湿層及び柔軟層２を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品２を作製し、同様に全光線透過率及び防湿保持性を測定した。結果を表３に示す。 Example 5
The weather-resistant layer, the flexible layer 2, the moisture-proof layer and the flexible layer 2 are laminated by vacuum lamination in the same manner as in Example 4 to produce the front protective sheet sealing material laminate 2, and the total light transmittance and moisture-proof retaining property are similarly obtained. Was measured. The results are shown in Table 3.
実施例６
　耐候性層、柔軟層３、防湿層及び柔軟層３を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品３を作製し、同様に全光線透過率及び防湿保持性を測定した。結果を表３に示す。 Example 6
The weather-resistant layer, the flexible layer 3, the moisture-proof layer, and the flexible layer 3 are laminated by vacuum lamination in the same manner as in Example 4 to produce the front protective sheet sealing material laminate 3 in the same manner. Was measured. The results are shown in Table 3.
実施例７
　耐候性層、柔軟層９、防湿層及び柔軟層９を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品４を作製し、同様に全光線透過率及び防湿保持性を測定した。結果を表３に示す。 Example 7
The weather-resistant layer, the flexible layer 9, the moisture-proof layer and the flexible layer 9 are laminated by vacuum lamination in the same manner as in Example 4 to produce the front protective sheet sealing material laminate 4, and the total light transmittance and moisture-proof retaining property are similarly obtained. Was measured. The results are shown in Table 3.
比較例６
　耐候性層，柔軟層４，防湿層，柔軟層４を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品５を作製し、同様に全光線透過率及び防湿保持性を測定した。その結果を表３に示す。 Comparative Example 6
A weather-resistant layer, a flexible layer 4, a moisture-proof layer, and a flexible layer 4 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminated product 5, and similarly, the total light transmittance and moisture-proof retaining property. Was measured. The results are shown in Table 3.
比較例７
　耐候性層，柔軟層５，防湿層，柔軟層５を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品６を作製し、同様に全光線透過率及び防湿保持性を測定した。その結果を表３に示す。 Comparative Example 7
A weather-resistant layer, a flexible layer 5, a moisture-proof layer, and a flexible layer 5 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminated product 6, and similarly, the total light transmittance and moisture-proof retaining property. Was measured. The results are shown in Table 3.
比較例８
　耐候性層，柔軟層６，防湿層，柔軟層６を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品７を作製し、同様に全光線透過率及び防湿保持性を測定した。その結果を表３に示す。 Comparative Example 8
A weather-resistant layer, a flexible layer 6, a moisture-proof layer, and a flexible layer 6 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminate 7 and similarly, the total light transmittance and moisture-proof retention Was measured. The results are shown in Table 3.
比較例９
　耐候性層，柔軟層７，防湿層，柔軟層７を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品８を作製し、同様に全光線透過率及び防湿保持性を測定した。その結果を表３に示す。 Comparative Example 9
The weather-resistant layer, the flexible layer 7, the moisture-proof layer, and the flexible layer 7 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminate 8 and similarly, the total light transmittance and moisture-proof retention. Was measured. The results are shown in Table 3.
比較例１０
　耐候性層，柔軟層８，防湿層，柔軟層８を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品９を作製し、同様に全光線透過率及び防湿保持性を測定した。その結果を表３に示す。 Comparative Example 10
A weather-resistant layer, a flexible layer 8, a moisture-proof layer, and a flexible layer 8 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminate 9 and similarly, the total light transmittance and moisture-proof retention property. Was measured. The results are shown in Table 3.
比較例１１
　耐候性層，柔軟層７，防湿層，柔軟層１を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品１０を作製し、同様に全光線透過率及び防湿保持性を測定した。その結果を表３に示す。 Comparative Example 11
The weather-resistant layer, the flexible layer 7, the moisture-proof layer, and the flexible layer 1 are laminated by vacuum lamination in the same manner as in Example 4 to produce the front protective sheet sealing material laminate 10, and the total light transmittance and moisture-proof retaining property are similarly obtained. Was measured. The results are shown in Table 3.
比較例１２
　耐候性層，柔軟層８，防湿層，柔軟層１を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品１１を作製し、同様に全光線透過率及び防湿保持性を測定した。その結果を表３に示す。 Comparative Example 12
A weather-resistant layer, a flexible layer 8, a moisture-proof layer, and a flexible layer 1 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminate 11, and similarly, the total light transmittance and moisture-proof retention. Was measured. The results are shown in Table 3.
参考例１
　耐候性層，柔軟層１，防湿層，柔軟層７を実施例４と同様に真空ラミを行い積層し前面保護シート封止材積層品１２を作製し、同様に全光線透過率及び防湿保持性を測定した。その結果を表３に示す。 Reference example 1
The weather-resistant layer, the flexible layer 1, the moisture-proof layer, and the flexible layer 7 are laminated by vacuum lamination in the same manner as in Example 4 to produce a front protective sheet sealing material laminate 12 and similarly, the total light transmittance and moisture-proof retention. Was measured. The results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　このようにして得られた本発明の前面保護シート封止材積層品１～４は、いずれも高防湿性と耐候性を兼備し、透明性にも優れるものであった。 The thus obtained front protective sheet sealing material laminates 1 to 4 of the present invention were both excellent in moisture resistance and weather resistance and excellent in transparency.
　本発明の前面保護シート封止材積層品に用いられた柔軟層１～３、９は、表３に示されるように、防湿層を保護するために必要な柔軟性と耐熱性および透明性との良好なバランスが図られた、十分な厚みを有したものであった。したがって、柔軟層１～３、９を用いて作製された実施例４～７の前面保護シート封止材積層品は、高防湿性と耐候性を兼備し、透明性にも優れるのみならず、その防湿層が、長期における高温・傾斜条件下での使用に耐え、落下物等からの衝撃からの保護が図られるものである。
　一方、柔軟層４，８は、耐熱性に劣り、高温下・傾斜条件で使用されることによれば、基準位置からずれたりシートが溶融したりすることが明らかとなった。したがって、柔軟層４，８を用いて作製された前面保護シート封止材積層品においては、柔軟層がその役割を果たしきれず、防湿層の保護が十分ではないものであった。すなわち、高温下・傾斜条件での使用が見込まれる太陽電池用部材の素材としては好ましくない。また、柔軟層５～７は、柔軟性（貯蔵弾性率）に劣り、防湿層の保護が不十分であることが示された。したがって、柔軟層５～７を用いて作製された前面保護シート封止材積層品においても、柔軟層がその役割を果たしきれず、防湿層の保護が十分ではないものであった。 As shown in Table 3, the flexible layers 1 to 3 and 9 used in the front protective sheet sealing material laminate of the present invention have the flexibility, heat resistance and transparency necessary for protecting the moisture-proof layer. The film had a sufficient thickness and a good balance. Therefore, the front protective sheet encapsulant laminates of Examples 4 to 7 produced using the flexible layers 1 to 3 and 9 have both high moisture resistance and weather resistance, and are not only excellent in transparency, The moisture-proof layer can withstand long-term use under high-temperature / inclined conditions, and can be protected from impact from falling objects.
On the other hand, the flexible layers 4 and 8 are inferior in heat resistance, and when used under high temperature / tilting conditions, it has been revealed that the flexible layers 4 and 8 are displaced from the reference position or the sheet is melted. Therefore, in the front protective sheet encapsulant laminate manufactured using the flexible layers 4 and 8, the flexible layer cannot fulfill its role, and the moisture-proof layer is not sufficiently protected. That is, it is not preferable as a material for a solar cell member that is expected to be used under high temperature and inclined conditions. Further, it was shown that the flexible layers 5 to 7 were inferior in flexibility (storage modulus) and the moisture-proof layer was not sufficiently protected. Accordingly, even in the front protective sheet sealing material laminate manufactured using the flexible layers 5 to 7, the flexible layer cannot fulfill its role, and the moisture-proof layer is not sufficiently protected.
１・・・・耐候層
２・・・・防湿層
３・・・・柔軟層
１０・・・前面保護シート
１２Ａ，１２Ｂ・・・封止樹脂層
１４Ａ，１４Ｂ・・・太陽電池素子
１６・・・バックシート
１８・・・ジャンクションボックス
２０・・・配線 DESCRIPTION OF SYMBOLS 1 ... Weatherproof layer 2 ... Moisture proof layer 3 ... Flexible layer 10 ... Front surface protection sheet 12A, 12B ... Sealing resin layer 14A, 14B ... Solar cell element 16 ...・ Back sheet 18 ... Junction box 20 ... Wiring

Claims (8)

  1. 　耐候層（Ａ）と防湿層（Ｂ）とを、下記(１)の条件を満足するエチレン－α－オレフィンランダム共重合体（Ｃ－１）と下記(２)の条件を満足するエチレン－α－オレフィンブロック共重合体（Ｃ－２）とを含有する柔軟層（Ｃ）を介して積層してなることを特徴とする太陽電池用前面保護シート。
    　　（１）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解熱量が０～７０Ｊ／ｇ
    　　（２）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解ピーク温度が１００℃以上であり、かつ、結晶融解熱量が５～７０Ｊ／ｇ     The weather-resistant layer (A) and the moisture-proof layer (B) are divided into an ethylene-α-olefin random copolymer (C-1) that satisfies the following condition (1) and an ethylene-α that satisfies the following condition (2): -A front protective sheet for a solar cell, which is laminated through a flexible layer (C) containing an olefin block copolymer (C-2).
    (1) The heat of crystal fusion measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 70 J / g.
    (2) The crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or more, and the crystal melting heat amount is 5 to 70 J / g.
  2. 　前記エチレン－α－オレフィンブロック共重合体（Ｃ－２）におけるα－オレフィンが、プロピレン、１－ブテン、１－へキセン及び１－オクテンからなる群より選ばれる少なくとも一種である請求項１に記載の太陽電池用前面保護シート。 2. The α-olefin in the ethylene-α-olefin block copolymer (C-2) is at least one selected from the group consisting of propylene, 1-butene, 1-hexene and 1-octene. Front protective sheet for solar cells.
  3. 　前記エチレン－α－オレフィンランダム共重合体（Ｃ－１）と前記エチレン－α－オレフィンブロック共重合体（Ｃ－２）を構成するα－オレフィンの種類が同一である請求項１又は２に記載の太陽電池用前面保護シート。 3. The type of α-olefin constituting the ethylene-α-olefin random copolymer (C-1) and the ethylene-α-olefin block copolymer (C-2) is the same. Front protective sheet for solar cells.
  4. 　請求項１～３のいずれかに記載の太陽電池用前面保護シートに、封止材（Ｄ）を積層してなる太陽電池用前面保護シート・封止材積層体。 A solar cell front protective sheet / sealing material laminate obtained by laminating the solar cell front protective sheet according to any one of claims 1 to 3 with a sealing material (D).
  5. 　前記封止材（Ｄ）が、下記(１)の条件を満足するエチレン－α－オレフィンランダム共重合体（Ｄー１）と下記(２)の条件を満足するエチレン－α－オレフィンブロック共重合体（Ｄー２）とを含有する請求項４記載の太陽電池用前面保護シート・封止材積層体。
    　　（１）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解熱量が０～７０Ｊ／ｇ
    　　（２）示差走査熱量測定における加熱速度１０℃／分で測定される結晶融解ピーク温度が１００℃以上であり、かつ、結晶融解熱量が５～７０Ｊ／ｇ     The sealing material (D) comprises an ethylene-α-olefin random copolymer (D-1) that satisfies the following condition (1) and an ethylene-α-olefin block copolymer that satisfies the following condition (2): The solar cell front protective sheet / sealing material laminate according to claim 4, comprising a coalescence (D-2).
    (1) The heat of crystal fusion measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 70 J / g.
    (2) The crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or more, and the crystal melting heat amount is 5 to 70 J / g.
  6. 　前記エチレン－α－オレフィンランダム共重合体（Ｄ－１）と前記エチレン－α－オレフィンブロック共重合体（Ｄ－２）を構成するα－オレフィンの種類が同一である、請求項５に記載の太陽電池用前面保護シート・封止材積層体。 6. The type of α-olefin constituting the ethylene-α-olefin random copolymer (D-1) and the ethylene-α-olefin block copolymer (D-2) is the same. Solar cell front protective sheet / sealing material laminate.
  7. 　請求項１～３のいずれかに記載の太陽電池用前面保護シート、または請求項４～６のいずれかに記載の太陽電池用前面保護シート・封止材積層体を用いて作製された太陽電池モジュール。 A solar cell produced using the solar cell front protective sheet according to any one of claims 1 to 3 or the solar cell front protective sheet / sealing material laminate according to any one of claims 4 to 6. module.
  8. 　請求項１～３のいずれかに記載の太陽電池用前面保護シート、請求項４～６のいずれかに記載の太陽電池用前面保護シート・封止材積層体又は請求項７に記載の太陽電池モジュールを用いて作製された太陽電池。 The solar cell front protective sheet according to any one of claims 1 to 3, the solar cell front protective sheet / sealing material laminate according to any one of claims 4 to 6, or the solar cell according to claim 7. Solar cell made using modules.
PCT/JP2011/067228 2010-08-31 2011-07-28 Front surface protective sheet for solar cell and solar cell module produced using same WO2012029465A1 (en)

Applications Claiming Priority (4)

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JP2010-195084 2010-08-31
JP2010195084 2010-08-31
JP2010-219131 2010-09-29
JP2010219131 2010-09-29

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1025357A (en) * 1996-07-12 1998-01-27 Dainippon Printing Co Ltd Transparent and composite film
JP2000174298A (en) * 1998-12-07 2000-06-23 Bridgestone Corp Solar cell, and cover material and seal film therefor
JP2010504646A (en) * 2006-09-20 2010-02-12 ダウ グローバル テクノロジーズ インコーポレイティド Electronic device module comprising ethylene multi-block copolymer
WO2010042335A1 (en) * 2008-10-09 2010-04-15 Dow Global Technologies Inc. Polyolefin film having an improved adhesive layer for airbag applications
JP2011040735A (en) * 2009-07-17 2011-02-24 Mitsubishi Plastics Inc Solar cell sealing material and solar cell module produced using the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1025357A (en) * 1996-07-12 1998-01-27 Dainippon Printing Co Ltd Transparent and composite film
JP2000174298A (en) * 1998-12-07 2000-06-23 Bridgestone Corp Solar cell, and cover material and seal film therefor
JP2010504646A (en) * 2006-09-20 2010-02-12 ダウ グローバル テクノロジーズ インコーポレイティド Electronic device module comprising ethylene multi-block copolymer
WO2010042335A1 (en) * 2008-10-09 2010-04-15 Dow Global Technologies Inc. Polyolefin film having an improved adhesive layer for airbag applications
JP2011040735A (en) * 2009-07-17 2011-02-24 Mitsubishi Plastics Inc Solar cell sealing material and solar cell module produced using the same

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