WO2016190146A1 - 太陽電池バックシート用フィルムおよびそれを用いてなる太陽電池バックシート並びに太陽電池 - Google Patents

太陽電池バックシート用フィルムおよびそれを用いてなる太陽電池バックシート並びに太陽電池 Download PDF

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WO2016190146A1
WO2016190146A1 PCT/JP2016/064417 JP2016064417W WO2016190146A1 WO 2016190146 A1 WO2016190146 A1 WO 2016190146A1 JP 2016064417 W JP2016064417 W JP 2016064417W WO 2016190146 A1 WO2016190146 A1 WO 2016190146A1
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Prior art keywords
film
solar cell
layer
solar
scs
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PCT/JP2016/064417
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English (en)
French (fr)
Japanese (ja)
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巽規行
堀江将人
千代敏弘
柴田優
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東レ株式会社
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Priority to KR1020177026257A priority Critical patent/KR20180013845A/ko
Priority to JP2016537583A priority patent/JP6743698B2/ja
Priority to CN201680023781.3A priority patent/CN107534067B/zh
Publication of WO2016190146A1 publication Critical patent/WO2016190146A1/ja

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/048—Encapsulation of modules
    • H01L31/049—Protective back sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/30—Properties of the layers or laminate having particular thermal properties
    • B32B2307/304—Insulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/12—Photovoltaic modules
    • 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 film for a solar battery back sheet, a solar battery back sheet using the film, and a solar battery.
  • FIG. 1 A typical configuration of a general solar cell is shown in FIG.
  • a power generation element 3 is sealed with a transparent sealing material 2 such as EVA (ethylene-vinyl acetate copolymer), a transparent substrate 4 such as glass, and a resin sheet called a solar cell back sheet 1. It is configured by sticking together.
  • Sunlight is introduced into the solar cell through the transparent substrate 4. Sunlight introduced into the solar cell is absorbed by the power generation element 3, and the absorbed light energy is converted into electric energy. The converted electric energy is taken out by a lead wire (not shown in FIG. 1) connected to the power generation element 3 and used for various electric devices.
  • the solar battery back sheet 1 is a sheet member that is installed on the back side of the power generation element 3 with respect to the sun and is not in direct contact with the power generation element 3.
  • the solar cell system and each member polyethylene-based, polyester-based, and fluorine-based resin films are mainly used. (See Patent Documents 1 to 3)
  • a technique has been developed that improves the efficiency of the solar battery module by reflecting the light that has passed between the solar battery cells with the solar battery backsheet and taking it into the cells.
  • JP-A-11-261085 Japanese Patent Laid-Open No. 11-186575 JP 2006-270025 A JP 2012-84670 A Japanese Patent No. 4766192
  • Patent Document 4 in the proposal of forming a reflective layer with white beads and white binder on the surface of the substrate, by using white beads, bonding is performed at the time of EVA or solar cell sealing material production. There exists a subject that adhesiveness with the other member film which falls. Further, as proposed in Patent Document 5, a proposal for forming a highly reflective backsheet by forming a layer including a cavity can achieve a certain power generation efficiency improvement effect, but is still insufficient for improving the power generation efficiency of the solar cell module. There was a problem of being.
  • the present invention provides a film for a solar battery back sheet that achieves both excellent output improvement effect and adhesion, a solar battery back sheet and a solar battery using the same. Is.
  • the present invention is a void-containing polyester film having a porosity of 10% or more of the entire film, and in the cross section in the thickness direction of the polyester film, a line perpendicular to the surface direction is formed from one surface of the film to the other surface.
  • the line connecting the one surface to the other surface is divided into four equal parts in the thickness direction (film thickness direction center point (C1 point), intermediate point between the film thickness direction center point and the film surface (C2- In each of the lines parallel to the plane direction of the film passing through each of (1 point) and (C2-2 point)) (divided horizontal line), the average area per cavity existing on the divided horizontal line passing through C1 is Sc.
  • ( ⁇ m 2), Scs an average area per cavity present on dividing the horizontal line passing through the C2-1 points ( ⁇ m 2), per one cavity present on dividing the horizontal line passing through the C2-2 points Average area 'when a ( ⁇ m 2), (Sc / Scs), (Sc / Scs' Scs a) is at least one of 1.1 to 35 or less of, the polyester resin constituting the polyester film of terminal carboxyl It is a film for solar battery back sheets having a base amount of 35 equivalents / ton or less.
  • the adhesiveness retention between the EVA resin which is a sealing material for solar battery cells and other member films to be bonded during backsheet processing ( Hereinafter, it is excellent in adhesion), and further, by mounting the solar cell back sheet of the present invention, a solar cell having higher power generation efficiency (hereinafter referred to as output improvement) than the conventional one can be provided.
  • the film for solar battery backsheet of the present invention is a void-containing polyester film having a porosity of 10% or more of the entire film, and faces from one surface of the film to the other surface in a cross section in the thickness direction of the polyester film.
  • a line perpendicular to the direction is drawn, and a line connecting the one surface to the other surface is divided into four equal parts in the thickness direction (film thickness direction center point (C1 point), film thickness direction center point and film surface
  • the film for solar battery backsheet of the present invention is a void-containing polyester film having a porosity of 10% or more of the whole film, and has a polyester resin as a main component.
  • the polyester resin as a main component means that the polyester resin is contained in an amount exceeding 50% by mass with respect to the resin constituting the polyester film of the present invention.
  • the polyester resin used in the present invention is: 1) polycondensation of dicarboxylic acid or its ester-forming derivative (hereinafter collectively referred to as “dicarboxylic acid component”) and diol component, 2) carboxylic acid or carboxylic acid derivative in one molecule And a polycondensation of a compound having a hydroxyl group and 1) 2).
  • the polymerization of the polyester resin can be performed by a conventional method.
  • dicarboxylic acid component malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid, eicosandioic acid, pimelic acid, azelaic acid, methylmalonic acid
  • Aliphatic dicarboxylic acids such as ethylmalonic acid
  • alicyclic dicarboxylic acids such as adamantane dicarboxylic acid, norbornene dicarboxylic acid, cyclohexane dicarboxylic acid, decalin dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4
  • a dicarboxy compound obtained by condensing oxyacids such as l-lactide, d-lactide, hydroxybenzoic acid and the like, or a combination of a plurality of such oxyacids, at least one carboxy terminus of the dicarboxylic acid component described above Can also be used.
  • aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, Aromatic diols such as cyclohexanedimethanol, spiroglycol, isosorbide, bisphenol A, 1,3-benzenedimethanol, 1,4-benzenedimethanol, 9,9'-bis (4-hydroxyphenyl) fluorene Group diols are typical examples. Moreover, these may be used independently or may be used in multiple types as needed. In addition, a dihydroxy compound formed by condensing a diol with at least one hydroxy terminal of the diol component described above can also be used.
  • examples of the compound having a carboxylic acid or a carboxylic acid derivative and a hydroxyl group in one molecule include oxyacids such as l-lactide, d-lactide and hydroxybenzoic acid, and derivatives thereof, oligomers of oxyacids, dicarboxylic acids Examples thereof include those obtained by condensing an oxyacid with one carboxyl group of the acid.
  • Polyester resins obtained from the above two components include polyethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate, polypropylene terephthalate, polybutylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate and mixtures thereof.
  • Polyethylene terephthalate and polyethylene-2,6-naphthalene dicarboxylate are preferred from the viewpoint of good film forming property, more preferably from the point that a film for a solar battery backsheet having better adhesion can be obtained. Most preferred is terephthalate.
  • the polyester resin constituting the polyester film needs to have a terminal carboxyl group content of 35 equivalents / ton or less. It is preferably 30 equivalent / ton or less, more preferably 25 equivalent / ton or less, still more preferably 20 equivalent / ton or less, and particularly preferably 17 equivalent / ton or less.
  • the film for solar cell backsheet of the present invention has 35 equivalents of the terminal carboxyl group amount of the polyester resin constituting the polyester film by controlling the size of the cavity contained in the film to a specific size as described later. It is possible to improve the adhesiveness even if it is less than / ton, and it is possible to achieve both excellent adhesiveness and heat-and-moisture resistance, and output improvement characteristics, which were difficult to achieve in the past.
  • the lower limit of the terminal carboxyl group amount is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 7 equivalents / ton or more, more preferably 11 amounts / ton or more.
  • the amount of the terminal carboxyl group is less than 7 equivalents / ton, the polar end groups on the surface are insufficient, the absolute value of the adhesion strength becomes small, and the adhesion improving effect of the present invention may be insufficient.
  • the intrinsic viscosity IV of the polyester resin constituting the polyester film is preferably 0.63 dl / g or more and 0.80 dl / g or less, more preferably 0.65 dl / g or more, and further preferably 0.67 dl / g or more.
  • the intrinsic viscosity IV is less than 0.63 dl / g, the adhesiveness may decrease as a result of a decrease in the dispersibility of the nucleating agent that forms cavities. Moreover, the heat-and-moisture resistance of a polyester film may also fall.
  • the intrinsic viscosity IV exceeds 0.80 dl / g, the extrudability of the polyester resin may deteriorate.
  • the intrinsic viscosity IV of the polyester resin constituting the polyester film is 0.63 dl / g or more and 0.80 dl / g or less. Therefore, by setting the intrinsic viscosity IV of the polyester resin constituting the polyester film to 0.63 dl / g or more and 0.80 dl / g or less, a film for a solar battery back sheet having both adhesiveness, heat-and-moisture resistance, and workability is obtained. Can do.
  • the number average molecular weight Mn of the polyester resin is preferably 8000 to 40,000, more preferably the number average molecular weight Mn is 9000 to 30000, and further preferably 10,000 to 20000.
  • the number average molecular weight Mn is less than 8000, durability such as heat and moisture resistance and heat resistance may be lowered.
  • the number average molecular weight Mn exceeds 40,000, the polymerization is difficult and the extrudability of the polyester resin may be deteriorated even if the polymerization is possible.
  • the polyester resin preferably contains Mn or Na as a metal element. It is preferable that Mn is contained in the range of 50 to 200 ppm and Na is contained in the range of 10 to 80 ppm. It is more preferable that Mn and Na are included in the above range. When Mn or Na is contained in the above range in the polyester resin, hydrolysis of the film is suppressed, and a film for a solar battery back sheet that has both excellent heat and moisture resistance, adhesion, and output improvement can be obtained. .
  • the polyester film of the present invention has a cavity inside.
  • the “cavity” was obtained when the film was cut perpendicularly to the film surface direction without crushing the film in the thickness direction using a microtome, and the cut surface of the film was observed using an electron microscope.
  • a cross-sectional area observed in the observation image represents a void having a size of 0.1 ⁇ m 2 or more.
  • the polyester film of the present invention needs to have a porosity (a ratio of voids in the film cross section) of 10% or more. More preferably, the porosity is 15% or more, and further preferably 20% or more.
  • the porosity of the entire film can be obtained from the area of the hollow portion in the observation image. Details of the method for measuring the porosity will be described later.
  • the porosity is less than 10%, the reflectivity is insufficient and the output improvement is reduced. Moreover, when there are too few voids, stress concentrates at the adhesion interface with other member films, and the adhesion of the film for solar cell backsheet is reduced.
  • the method for forming the cavities in the polyester film is not particularly limited, but a method of forming the cavities in the polyester film and then stretching it is preferable. It is difficult to control the structure of the cavity formed by the foaming agent or the like, and the adhesiveness of the solar battery backsheet film may be lowered.
  • examples of the cavity nucleating agent include organic nucleating agents such as olefin resins that are incompatible with the polyester resin, and inorganic nucleating agents such as inorganic particles and glass beads.
  • An organic nucleating agent is preferable as the cavity nucleating agent from the viewpoint that it is easy to incline the shape of the cavity in the thickness direction by a manufacturing method described later. By providing the hollow shape with an inclination in the thickness direction, the adhesion of the solar battery backsheet film can be enhanced.
  • Organic nucleating agents include olefin resins, nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, nylon 46, nylon MXD6, nylon 6T, and other polyamide resins, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene- Styrene resins such as styrene copolymers, acrylic resins such as polymethyl methacrylate and polybutyl methacrylate, fluorine resins such as polytetrafluoroethylene and polyvinylidene fluoride, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, poly Also used for super engineering plastics such as etherimide, or different types of polyester resins that are incompatible with the polyester resin of the polyester film of the present invention.
  • olefin resins nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, nylon 46, nylon MXD6, nylon 6T, and other polyamide resins
  • Rukoto can.
  • the olefin resin include aliphatic polyolefin resins such as polypropylene, polyethylene, high density polyethylene, low density polypropylene, ethylene-propylene copolymer, polymethylpentene, and cyclic polyolefin resins such as cycloolefin polymer and cycloolefin copolymer.
  • an olefin-based resin having a Vicat softening point of 140 ° C. or higher is preferable as the organic nucleating agent from the viewpoint of excellent output improvement of the film for a solar battery backsheet by forming a fine cavity and improving the reflectivity.
  • An olefin resin having a temperature of at least ° C is more preferable.
  • the shape of the cavities may become too coarse, and the film adhesion for a solar battery backsheet and the output improvement may be reduced.
  • the amount of the organic nucleating agent contained in the polyester film is preferably 1% by mass or more and 30% by mass or less, more preferably 4% by mass or more and 15% by mass or less, and still more preferably, with respect to the total mass of the polyester film. Is 8 mass% or more and 13 mass% or less.
  • the amount of the organic nucleating agent contained in the polyester film is less than 1% by mass, the film for solar battery backsheet is excellent in adhesion, but may be inferior in output improvement due to decrease in reflectivity.
  • the amount of the organic nucleating agent exceeds 30% by mass, although the output improvement is excellent, there are cases where there are too many cavities and the adhesion is poor.
  • a dispersion aid when an organic nucleating agent is used, it is preferable to use a dispersion aid at the same time.
  • a polyester elastomer or an amorphous polyester resin in which a polyether structure, a bent skeleton structure, a bulky cyclohexane skeleton structure, or the like is copolymerized is preferably used.
  • a form in which two or more kinds of dispersion aids are used in combination is also preferably used.
  • the amount of the dispersion aid contained in the polyester film is preferably 1% by mass or more and 10% by mass or less, more preferably 2% by mass or more and 8% by mass or less, and still more preferably with respect to the total mass of the polyester film. It is 3 mass% or more and 6 mass% or less.
  • the amount of the dispersion aid contained in the polyester film is less than 1% by mass, the effect as the dispersion aid is insufficient, and the adhesion may be lowered.
  • the amount of the dispersion aid exceeds 10% by mass, the dispersibility may be excessively improved, and the adhesion may be lowered. Furthermore, there is a risk that the heat and humidity resistance of the polyester film may be lowered due to the decrease in crystallinity.
  • the cavity in the observation image of the cross section in the thickness direction of the polyester film draws a line perpendicular to the surface direction from one surface of the film to the other surface, Three points dividing the line connecting one surface into four in the thickness direction (film thickness direction center point (C1 point), intermediate point between the film thickness direction center point and the film surface (C2-1 point), (C2-2 In the line parallel to the plane direction of the film passing through the point)) (divided horizontal line), the average area per cavity existing on the divided horizontal line passing through the point C1 is Sc ( ⁇ m 2 ), and the dividing through the point C2-1
  • the average area per cavity existing on the horizontal line is Scs ( ⁇ m 2 )
  • the average area per cavity existing on the divided horizontal line passing through the point C2-2 is Scs ′ ( ⁇ m 2 ), Sc / Scs)
  • At least one of (Sc / Scs ′) is a polyester film of 1.1 to 35.
  • they are 1.5 or more and 20 or less, More preferably, they are 2.0 or more and 15 or less, More preferably, they are 2.5 or more and 10 or less. Details of how to obtain Sc ( ⁇ m 2 ), Scs ( ⁇ m 2 ), and Scs ′ ( ⁇ m 2 ) will be described later.
  • the size of the void contained in the film is at least one of (Sc / Scs) and (Sc / Scs ′) of 1.1 or more and 35 or less. It has been surprisingly found that the adhesion improves when the thickness direction is inclined so that It is not completely clear why this effect occurs, but the inventors presume as follows. If both (Sc / Scs) and (Sc / Scs') are less than 1.1 (the inclination of the size of the cavities contained in the film is small in the thickness direction), fine cavities are formed inside the polyester film.
  • (Sc / Scs) and (Sc / Scs') indicate the shape of the cavity, the type of the cavity nucleating agent, the amount of the cavity nucleating agent, the amount of the dispersing agent, or the polyester resin after melt extrusion at the time of film production. It can be adjusted by the cooling rate. For example, by using an olefin resin having a Vicat softening point of 140 ° C. or higher as an organic nucleating agent, and increasing the amount of the cavity nucleating agent and the amount of the dispersion aid within a preferable range, the cavities can be uniformly refined and the The amount of cavities increases and (Sc / Scs) and (Sc / Scs') decrease.
  • the film for solar cell backsheet of the present invention adjusts the type of the inner cavity nucleating agent, the amount of the cavity nucleating agent, the amount of the dispersing agent, or the cooling rate of the polyester resin after melt extrusion at the time of film production within a preferable range.
  • at least one of the hollow (Sc / Scs) and (Sc / Scs') inside the polyester film is 1.1 to 35, and the solar cell back sheet has both excellent adhesion and improved output. It can be a film.
  • both (Sc / Scs) and (Sc / Scs ′) are in the range of 1.1 to 35, the adhesion on both surfaces of the solar battery backsheet film is excellent. Even in a configuration in which one side of the film for solar battery backsheet is bonded to another member film and the other side is directly bonded to the solar battery cell, it is more preferable because excellent adhesion can be obtained on both surfaces of the film. .
  • the film for solar battery backsheet of the present invention can increase the power generation output by reusing light by reflecting the light that has passed between the solar battery cells while diffusing with the solar battery backsheet.
  • a form in which inorganic particles are contained in the polyester resin composition constituting the polyester film is preferable.
  • the inorganic particles used here include calcium carbonate, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide, cerium oxide, magnesium oxide, barium sulfate, zinc sulfide, calcium phosphate, alumina, mica, mica, talc, clay, and kaolin. , Lithium fluoride, calcium fluoride, and the like.
  • titanium oxide examples include crystalline titanium oxide such as anatase type titanium oxide and rutile type titanium oxide. From the viewpoint of increasing the difference in refractive index from the polyester used, titanium oxide having a refractive index of 2.7 or more is preferable, and at the same time, rutile type titanium oxide is used from the viewpoint of superior ultraviolet resistance. Further preferred. That is, the film for solar cell backsheets of this invention can improve output improvement more by making an inorganic particle be included in the polyester resin composition which comprises the polyester film which has the said cavity.
  • the resin composition which comprises a polyester film contains an inorganic particle here, it has a laminated structure of 3 layers or more, and both surface layers (one surface layer is P2 layer) And the other surface layer is a P2 ′ layer) at least one resin composition contains inorganic particles and does not have a surface layer (this layer is a P1 layer) Is preferably a structure containing the above-described cavity nucleating agent, and more preferably a three-layer structure including P2 layer / P1 layer / P2 ′ layer.
  • the porosity (Ps) of the P2 layer and the porosity (Ps ′) of the P2 ′ layer are preferably 5.0% or less, more preferably 4.0% or less, and still more preferably 3.5%. It is as follows. When either of the porosity (Ps) and (Ps ′) of the P2 layer and the P2 ′ layer exceeds 5.0%, the surface layer side may become unstable in the cavity area and the adhesion may be lowered. .
  • the porosity (Ps) of the P2 layer and the porosity (Ps ′) of the P2 ′ layer are 5.0% or less, without reducing the adhesion,
  • the reflectivity of the P1 layer and the diffusibility of the P2 layer or the P2 ′ layer can be utilized without canceling each other, and the output improvement can be further improved.
  • process contamination by the cavity nucleating agent can be prevented during the production of the polyester film.
  • the solar battery cell that expects the effect of the present invention Adhesion can be further improved by positioning the P2 layer or the P2 ′ layer that satisfies the above range on the side.
  • the structure having the P2 layer or the P2 ′ layer containing the inorganic particles having ultraviolet resistance in the surface layer of the film for the solar battery backsheet of the present invention is effective for improving the output and for the solar battery backsheet by the ultraviolet rays hitting the solar battery cell.
  • the laminated structure which has an inorganic particle in both the resin composition which comprises a P2 layer and a P2 'layer has the effect of the ultraviolet-ray resistance by the side of the said photovoltaic cell with respect to the reflected light of the ultraviolet ray which hits the back surface of a solar cell. It can also be demonstrated, and it can be said that it is a more preferable form.
  • the main components of the P2 layer and the P2 ′ layer can be freely selected as long as the effects of the present invention are not impaired.
  • a film for a solar battery back sheet having excellent adhesion between the P1 layer and the P2 layer interface can be obtained.
  • an acrylic resin or the like as the main component of the P2 layer, it becomes possible to provide a P2 layer with a higher filling of inorganic particles on the P1 layer by a coating method, and to achieve both excellent adhesion and improved output. It can be set as the film for battery back sheets.
  • the thickness of the P1 layer is T1 ( ⁇ m)
  • the thickness of the P2 layer is T2 ( ⁇ m)
  • the P2 ′ layer is W2 (mass%)
  • the inorganic particle concentration contained in the resin composition constituting the P2 ′ layer is W2 ′ (mass). %)
  • At least one of (T2 / T1) ⁇ W2 and (T2 ′ / T1) ⁇ W2 ′ preferably satisfies 0.35 or more and 1.50 or less. More preferably, they are 0.75 or more and 1.40 or less, More preferably, they are 0.90 or more and 1.20 or less.
  • both (T2 / T1) ⁇ W2 and (T2 ′ / T1) ⁇ W2 ′ are less than 0.35, the diffusibility of the P2 layer and the P2 ′ layer is insufficient, and either layer is a solar cell. Even if it installs in the side, the output improvement property of the film for solar cell backsheets may fall.
  • both (T2 / T1) ⁇ W2 and (T2 ′ / T1) ⁇ W2 ′ exceed 1.50, the diffusibility of the P2 layer and the P2 ′ layer becomes too strong, and the light reaches the P1 layer. However, the output improvement performance may be reduced.
  • the inorganic particle concentration is preferably 10% by mass or less with respect to the total mass of the P1 layer, from the viewpoint of maintaining the excellent adhesion of the solar cell backsheet film. More preferably, it is more preferably 3% by weight or less.
  • the inorganic particle content of the P1 layer exceeds 10% by mass, (Sc / Scs) or (Sc / Scs') of the polyester film becomes small, and the adhesion of the film for solar battery backsheet may be lowered.
  • T1 / (T1 + T2 + T2 ′) indicating the ratio of the P1 layer to the total film thickness is preferably in the range of 0.6 or more and 0.99 or less, and the P2 layer and P2 ′ with respect to the total film thickness.
  • T2 / (T1 + T2 + T2 ′) and T2 ′ / (T1 + T2 + T2 ′), which indicate the proportion of the layer, are preferably 0.01 or more and 0.2 or less.
  • the film for solar cell backsheet of the present invention if necessary, other than the above-described hollow nucleating agent and inorganic particles, as long as the effect of the present invention is not impaired, a heat-resistant stabilizer, an oxidation-resistant stabilizer, an ultraviolet absorption Additives such as an agent, an ultraviolet stabilizer, an organic / inorganic lubricant, an organic / inorganic fine particle, a filler, a nucleating agent, a dye, and a coupling agent may be blended.
  • an ultraviolet absorber is selected as an additive, the ultraviolet resistance of the solar cell backsheet film of the present invention can be further enhanced.
  • the electrical insulation can be improved by adding an antistatic agent or the like.
  • the total thickness of the solar cell backsheet film of the present invention is preferably 25 ⁇ m or more and 350 ⁇ m or less, more preferably 30 ⁇ m or more and 300 ⁇ m or less, and further preferably 50 ⁇ m or more and 260 ⁇ m or less.
  • the film for solar battery backsheet of the present invention has a thickness of less than 25 ⁇ m, wrinkles may occur during bonding with other member films.
  • the thickness is greater than 350 ⁇ m, the winding property may deteriorate.
  • the thickness of the entire film is 45 ⁇ m or more, the effect of improving the adhesion due to the above-described deviation of the cavity area in the thickness direction can be remarkably obtained, and the output improvement effect can be obtained because the light reflectivity is good.
  • it is 48 micrometers, More preferably, it is 50 micrometers or more.
  • the film for solar cell backsheet of the present invention preferably has a thermal conductivity of 0.9 W / m ⁇ K or less, and more preferably 0.75 W / m ⁇ K or less.
  • another film may be laminated on the surface opposite to the surface in close contact with the sealing material (hereinafter referred to as the air side surface).
  • the thermal conductivity of the solar cell backsheet film can be lowered by increasing the porosity of the solar cell backsheet film.
  • the polyester resin used as the raw material for the solar cell backsheet film of the present invention can be obtained by subjecting dicarboxylic acid or its ester derivative and diol to a transesterification or esterification reaction by a well-known method.
  • reaction catalysts include alkali metal compounds, alkaline earth metal compounds, zinc compounds, lead compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, titanium compounds, and phosphorus compounds.
  • an alkali metal compound, a manganese compound, an antimony compound or a germanium compound, or a titanium compound is preferably added as a polymerization catalyst at any stage before the normal production method is completed, and the solar battery backsheet film is adhered.
  • a sodium compound or a manganese compound from the viewpoint of further improving the properties.
  • a manganese compound for example, when a manganese compound is taken as an example, it is preferable to add the manganese compound powder as it is.
  • the terminal carboxyl group amount of the polyester resin is determined by heating at a temperature during polymerization or after polymerization of the polyester resin at a temperature of 190 ° C. to less than the melting point of the polyester resin under reduced pressure or an inert gas flow such as nitrogen gas.
  • the so-called solid-state polymerization time can be controlled. Specifically, the amount of terminal carboxyl groups increases as the polymerization temperature increases, and the amount of terminal carboxyl groups decreases as the time of solid phase polymerization increases.
  • the method for incorporating a cavity nucleating agent, inorganic particles, etc. into the film for solar cell backsheet of the present invention is to prepare master pellets prepared by melting and kneading raw materials in advance using a vent type biaxial kneading extruder or tandem type extruder. A blending method is preferred. At this time, since the master pellet receives a heat history, there is a concern that the heat deterioration is not a little progressed. Therefore, it is more preferable to prepare a master pellet containing the cavity nucleating agent and inorganic particles at a higher concentration, and mix and dilute them.
  • a master pellet having a larger content than the content of the cavity nucleating agent to be contained in the polyester film is prepared in advance. It mixes with the polyester resin which is the main component of a polyester film, and adjusts to the target content.
  • the method for producing a film for a solar battery backsheet according to the present invention is a method in which a raw material adjusted to have a polyester film composition is heated and melted in an extruder and extruded from a die cooled onto a cast drum to be processed into a sheet shape.
  • the method (melt cast method) can be used.
  • the film for solar battery backsheet of the present invention is preferably cooled at a cast drum temperature of 30 to 80 ° C., more preferably 40 to 70 ° C., and further preferably 45 to 60 ° C.
  • the obtained sheet is led to a roll group heated to a temperature of 70 to 140 ° C., stretched in the longitudinal direction (longitudinal direction, that is, the traveling direction of the sheet), and cooled by a roll group having a temperature of 20 to 50 ° C. .
  • the both ends of the sheet are guided to a tenter while being held by clips, and are stretched in a direction (width direction) perpendicular to the longitudinal direction in an atmosphere heated to a temperature of 80 to 150 ° C.
  • the draw ratio is preferably 2 to 30 times in terms of surface magnification, more preferably 4 to 25 times, and still more preferably 6 to 20 times.
  • a cavity having an appropriate size can be formed in the polyester film of the present invention. If the surface magnification is less than twice, the cavity may be small and output improvement may be reduced. On the other hand, when the surface magnification exceeds 30 times, the cavity may become too large and the adhesion may be lowered. Also, it is not preferable from the viewpoint of excessive load on the film forming machine.
  • the difference between the stretching ratios in the longitudinal direction (running direction during film formation) and the width direction of the film is preferably 4 times or less, more preferably 2 times or less, and still more preferably 1 time or less.
  • the difference in the draw ratio exceeds 4 times, the shape of the cavity inside the polyester film is biased in one direction, and the adhesion may be lowered.
  • the film for the solar battery backsheet of the present invention is a polyester film in which the difference in the draw ratio between the longitudinal direction (running direction during film formation) and the width direction of the film is 4 times or less, and the surface magnification is 2 times or more and 30 times.
  • the set temperature at this time is preferably 150 ° C. or higher and 250 ° C. or lower, more preferably 170 ° C. or higher and 230 ° C. or lower, and further preferably 180 ° C. or higher and 220 ° C. or lower.
  • heat setting is performed at less than 150 ° C., the thermal dimensional stability of the solar cell backsheet film is lowered, and there is a risk of problems such as curling during backsheet processing.
  • heat setting is performed at a temperature exceeding 250 ° C., the hollow nucleating agent inside the film may flow and the desired reflection performance may not be obtained.
  • the film for solar cell backsheets of the present invention has a P2 layer
  • the raw material constituting the P1 layer and the raw material constituting the P2 layer are put into two different extruders, melted, and then merged
  • a method of co-extrusion on a cast drum cooled from a die and processing it into a sheet (co-extrusion method), or a raw material constituting the P2 layer dissolved in a solvent after forming a polyester film having a P1 layer alone
  • a method (coating method) in which the P2 layer is formed by applying a roll coating method, a dip coating method, a bar coating method, a die coating method, a gravure roll coating method and the like and then drying the solvent is preferably used.
  • the solar cell backsheet film obtained by the above production method is excellent while maintaining the heat and moisture resistance, heat resistance, ultraviolet resistance, thermal dimensional stability, and workability of the conventional solar cell backsheet film. It is possible to achieve both adhesion and output improvement.
  • the solar cell backsheet of this invention is a solar cell backsheet having the film for solar cell backsheet of the present invention and at least one functional layer.
  • required by the measuring method mentioned later is 10 mm or less, and it is more preferable that it is 5 mm or less.
  • the Young's modulus of the solar battery back sheet film is 4.0 GPa or less, and the Young's modulus of the solar battery back sheet is 4.0 GPa or less. Is preferred. More preferably, the Young's modulus of the solar cell backsheet film is 4.0 GPa or less, and the Young's modulus of the solar cell backsheet is more preferably 3.0 GPa or less.
  • the lower limit of the Young's modulus of the solar cell backsheet film and the solar cell backsheet is not particularly limited as long as the function of the present invention is not impaired, but 0.5 GPa or more is sufficient.
  • the solar battery back sheet By setting the Young's modulus of the solar battery back sheet to 4.0 GPa or less, when stacking the curl generated when the solar battery back sheet is stored in a roll state on the solar battery, the solar battery back sheet is caused by its own weight. Can be flattened.
  • the method for setting the Young's modulus of the solar cell backsheet film in the above range is not particularly limited, but can be adjusted by the following method. For example, when the porosity in the polyester film for solar battery backsheet is increased or the draw ratio during film formation is decreased, the Young's modulus of the film for solar battery backsheet tends to be lowered.
  • the Young's modulus of the film for solar battery back sheets tends to increase.
  • the Young's modulus of the solar battery backsheet tends to be high when the Young's modulus of the film for solar battery backsheet used for the solar battery backsheet is high, and low when it is low.
  • it can adjust with the Young's modulus of the layer laminated
  • the functional layer of the solar battery backsheet of the present invention is preferably a layer containing at least one of polyethylene, polypropylene, and ethylene vinyl acetate copolymer, or a combination of a plurality of combinations, because the adhesion becomes good.
  • the solar cell backsheet of the present invention by having the functional layer between the solar cell backsheet film and the encapsulant, it becomes possible to have good adhesion to the encapsulant.
  • the thickness of the functional layer is preferably 30 ⁇ m or more and 300 ⁇ m or less, and 50 ⁇ m or more and 200 ⁇ m or less. It is more preferable that By setting the thickness of the layer to 30 ⁇ m or more, water vapor barrier properties and insulating properties are improved, and by setting the thickness to 300 ⁇ m or less, it is possible to suppress process contamination due to the protrusion of the functional layer B at the time of manufacturing a solar cell.
  • the method of laminating the layer containing at least one of polyethylene, polypropylene, and ethylene vinyl acetate copolymer or a combination thereof with the film for solar cell backsheet of the present invention as a functional layer is not particularly limited.
  • a method of directly laminating the film for solar cell backsheet of the present invention, and a method of laminating the film for solar cell backsheet of the present invention and a functional layer via an adhesive or the like within a range not inhibiting the effects of the present invention. can be mentioned.
  • the functional layer of the backsheet of the present invention is composed of polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropolypropylene copolymer.
  • a layer containing at least one of (FEP) or a combination thereof is preferable because the weather resistance of the backsheet can be improved.
  • the functional layer is laminated on the air side surface of the film for solar battery backsheet of the present invention because deterioration due to ultraviolet rays can be suppressed.
  • the functional layer preferably contains at least one of PVF and PVDF.
  • the thickness of the functional layer is preferably 25 ⁇ m or more and 125 ⁇ m or less, and is 25 ⁇ m or more and 75 ⁇ m or less. It is more preferable. When the thickness of the layer is 25 ⁇ m or more, the weather resistance is improved, and when it is 125 ⁇ m or less, the workability of the solar battery back sheet is improved.
  • the method of laminating the layer containing at least one of PVF, PVDF, PTFE, and ETFE as a functional layer on the film for solar cell backsheet of the present invention is not particularly limited. And a method of laminating the solar cell backsheet film of the present invention and a functional layer via an adhesive or the like within a range not impairing the effects of the present invention.
  • the functional layer of the solar cell backsheet of the present invention is preferably a layer containing polyurethane, since the adhesion becomes good.
  • the functional layer is located between the film for solar battery backsheet of the present invention and the sealing material, the adhesion with the sealing material is improved.
  • the polyurethane here is a general term for polymers obtained from a compound having an isocyanate group and a compound having a hydroxyl group.
  • the compound having a hydroxyl group examples include polyester polyols, polyether polyols, polyacrylic polyols, and fluorine-based polyols, and polyacrylic polyols and fluorine-based polyols are preferable from the viewpoint of heat and moisture resistance and weather resistance.
  • the thickness of the functional layer is preferably 1 ⁇ m or more and 20 ⁇ m or less, and more preferably 2 ⁇ m or more and 10 ⁇ m or less.
  • the weather resistance is improved by setting the thickness of the functional layer to 1 ⁇ m or more, and the workability of the backsheet is improved by setting the thickness to 20 ⁇ m or less.
  • the method of laminating a layer containing polyurethane as a functional layer with the film for solar battery backsheet of the present invention is not particularly limited, but roll coating, gravure roll coating, kiss coating, and other coating methods, or The method of laminating by a printing method etc. is mentioned.
  • the functional layer of the solar cell backsheet of this invention contains an inorganic compound. When the functional layer of the solar cell backsheet contains an inorganic compound, the water vapor barrier property of the solar cell backsheet is improved.
  • silica and alumina are preferable, and silica is particularly preferable in terms of water vapor barrier property and heat and moisture resistance.
  • the method for laminating the layer containing the inorganic compound as a functional layer with the film for solar cell backsheet of the present invention is not particularly limited, but the method for directly laminating the film for solar cell backsheet of the present invention or the present invention. Layers other than the polyester film obtained by laminating the film for solar cell backsheet of the present invention and the inorganic compound as long as the inorganic compound is laminated on the polyester film different from the film for solar cell backsheet of the present invention and the effect of the present invention is not impaired. And a method of laminating the layer via an adhesive or the like.
  • the solar cell backsheet of the present invention is excellent in weather resistance and workability when a functional layer containing polyester is laminated with the film for solar cell backsheet of the present invention via an adhesive layer to form a solar cell backsheet. preferable.
  • the thickness of the functional layer is preferably 25 ⁇ m or more and 188 ⁇ m or less, and more preferably 38 ⁇ m or more and 125 ⁇ m or less. It is possible to improve the weather resistance by increasing the thickness of the layer to 25 ⁇ m or more, and to improve the workability of the backsheet by reducing the thickness to 188 ⁇ m or less.
  • the film for solar cell backsheets of this invention has a functional layer laminated
  • porosity, (Sc / Scs), (Sc / Scs') are adhesive layers. And not including the functional layer.
  • porosity, (Sc / Scs), (Sc / Scs') are adhesive layers.
  • the center point in the direction of the thickness of the void-containing polyester film is C1, and C1 and the void-containing polyester film
  • the intermediate points with the surface are (C2-1 point) and (C2-2 point).
  • the solar cell of this invention mounts the said film for solar cell backsheets as it is.
  • the solar battery back sheet is mounted.
  • a structural example of the solar cell of the present invention is shown in FIG.
  • a transparent substrate 4 such as glass and a solar cell back sheet 1
  • a power generating element connected with a lead wire (not shown in FIG. 1) for taking out electricity is sealed with a transparent sealing material 2 such as EVA resin.
  • a transparent sealing material 2 such as EVA resin.
  • the present invention is not limited to this and can be used for any configuration.
  • the solar battery back sheet 1 plays a role of protecting the power generation cell installed on the back surface of the sealing material 2 in which the power generation element is sealed.
  • the solar battery backsheet is disposed so that the P2 layer is in contact with the sealing material 2 in terms of increasing the power generation efficiency of the solar battery.
  • the power generating element 3 converts light energy of sunlight into electric energy, and is based on crystalline silicon, polycrystalline silicon, microcrystalline silicon, amorphous silicon, copper indium selenide, compound semiconductor, dye enhancement Arbitrary elements such as a sensitive system can be used in series or in parallel according to the desired voltage or current depending on the purpose. Since the transparent substrate 4 having translucency is located on the outermost surface layer of the solar cell, a transparent material having high weather resistance, high contamination resistance, and high mechanical strength characteristics in addition to high transmittance is used. In the solar cell of the present invention, the transparent substrate 4 having translucency can be made of any material as long as the above characteristics are satisfied. Examples thereof include glass, ethylene tetrafluoride-ethylene copolymer (ETFE), polyfluoride.
  • ETFE ethylene tetrafluoride-ethylene copolymer
  • Vinyl fluoride resin PVDF
  • PVDF polyvinylidene fluoride resin
  • TFE polytetrafluoroethylene resin
  • FEP tetrafluoroethylene-hexafluoropropylene copolymer
  • CFE polytrifluoroethylene chloride resin
  • Fluorinated resins such as polyvinylidene fluoride resin, olefinic resins, acrylic resins, and mixtures thereof.
  • glass it is more preferable to use a tempered glass.
  • stretched the said resin uniaxially or biaxially from a viewpoint of mechanical strength is used preferably.
  • the adhesiveness with EVA resin etc. which are the sealing materials of an electric power generation element, it is also preferably performed to give the surface a corona treatment, a plasma treatment, an ozone treatment, and an easy adhesion treatment. .
  • the sealing material 2 for sealing the power generating element covers the surface of the power generating element with resin and fixes it, protects the power generating element from the external environment, and has a light-transmitting base material for the purpose of electrical insulation.
  • a material having high transparency, high weather resistance, high adhesion, and high heat resistance is used to adhere to the backsheet and the power generation element. Examples thereof include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA) resin, ethylene-methacrylic acid copolymer (EMAA), Ionomer resins, polyvinyl butyral resins, and mixtures thereof are preferably used.
  • the film for solar cell backsheet of the present invention on a solar cell as a solar cell backsheet, even when placed outdoors for a long period of time compared to conventional solar cells, Adhesiveness is maintained, and further, power generation efficiency can be increased.
  • the solar cell of the present invention can be suitably used for various applications without being limited to outdoor use and indoor use such as a solar power generation system and a power source for small electronic components.
  • the indicator at the time of titration used phenol red, and the place where it changed from yellowish green to light red was set as the end point of titration. If there is an insoluble matter such as inorganic particles in the solution in which the measurement sample is dissolved, the solution is filtered to measure the mass of the insoluble matter, and the value obtained by subtracting the mass of the insoluble matter from the measurement sample mass is measured. The following correction was made.
  • fluorescent X-ray analysis method fluorescent X-ray analyzer (model number: 3270) manufactured by Rigaku Corporation) is used. Quantification was carried out by atomic absorption spectrometry (manufactured by Tadate Corporation: Polarized Zeeman atomic absorption photometer 180-80, frame: acetylene-air).
  • a line perpendicular to the film thickness direction is drawn for each observed image, and the line is divided into four equal points (film thickness direction center point (C1 point), intermediate point between the film thickness direction center point and the film surface)
  • a line parallel to the thickness direction is drawn on the film passing through (C2-1 point) and (C2-2 point).
  • the number of cavities to be traced if there are less than 20 cavities on the divided horizontal line in the observation image, all cavities are traced, and if there are 20 or more cavities, the center of gravity of the cavities is It is assumed that 20 cavities close to the points C1, C2-1, and C2-2 are selected and traced.
  • the film side for the solar battery backsheet of the present invention was horizontally fixed, and the peel strength when the peeled portion was subjected to a peel test at 180 ° peel at a speed of 200 mm / min. was measured, and the adhesion of the solar cell backsheet film was determined as follows.
  • peel strength When peel strength is 6N / 15mm or more: A When peel strength is 4N / 15mm or more and less than 6N / 15mm: B When peel strength is 2N / 15mm or more and less than 4N / 15mm: C When peel strength is 1N / 15mm or more and less than 2N / 15mm: D When peel strength is less than 1 N / 15 mm: E Adhesiveness is good from A to D, and among them, A is the best.
  • the wet heat resistance was determined as follows.
  • A When the breaking elongation after the wet heat test is 40% or more and less than 60% of the breaking elongation before the wet heat test: B When the breaking elongation after the wet heat test is 20% or more and less than 40% of the breaking elongation before the wet heat test: C When the breaking elongation after the wet heat test is 10% or more and less than 20% of the breaking elongation before the wet heat test: D When the breaking elongation after the wet heat test is less than 10% of the breaking elongation before the wet heat test: E The wet heat resistance is good in A to D, and A is the best among them.
  • UV resistance color change during UV treatment test
  • b value Color tone (b value) measurement Based on JIS-Z-8722 (2000), a spectroscopic color difference meter SE-2000 (manufactured by Nippon Denshoku Industries Co., Ltd., light source halogen lamp 12V4A, 0 ° to ⁇ 45 °)
  • the test was done so that an ultraviolet test light might hit the surface of the P2 layer side.
  • the functional layer B is provided on the surface opposite to the surface having the functional layer B, and in Examples 38 to 44 and 47 to 49, The test was conducted so that the ultraviolet test light hits the surface having the functional layer B ′ in 54 to 56.
  • Thermal conductivity is 0.08 W / m ⁇ K or less: A Thermal conductivity is over 0.08 W / m ⁇ K and 0.12 W / m ⁇ K or less: B Thermal conductivity exceeds 0.12 W / m ⁇ K and 0.14 W / m ⁇ K or less: C Thermal conductivity exceeds 0.14 W / m ⁇ K: D The thermal conductivity is good from A to B, and A is the best among them.
  • Solar cell characteristic evaluation (7-1) Solar cell output improvement evaluation
  • the flux “HOZAN H722” is applied to the front and back silver electrode portions of the polycrystalline silicon solar cell “Gintech G156M3”.
  • a wiring material “copper foil SSA-SPS0.2 ⁇ 1.5 (20) manufactured by Hitachi Cable, Ltd.” cut into a length of 155 mm on the front and back silver electrodes was applied with a dispenser, and the cell on the front side Place the wire 10 mm away from one end of the wire on the end of the wiring material and the back side to be symmetrical with the front side, and use the soldering iron to bring the soldering iron into contact from the back side of the cell so that the front and back sides are simultaneously Solder welding was performed to produce 1 cell strings.
  • the longitudinal direction of the wiring material protruding from the cell of the produced 1 cell string and the longitudinal direction of the extraction electrode “copper foil A-SPS0.23 ⁇ 6.0 manufactured by Hitachi Cable, Ltd.” cut into 180 mm are shown. Placed vertically, the flux was applied to the portion where the wiring material and the extraction electrode overlapped, and solder welding was performed, thereby producing strings with extraction electrodes. At this time, the short-circuit current was measured according to the standard state of JIS C8914: 2005, and the power generation performance of the cell alone was obtained.
  • 190 mm ⁇ 190 mm glass (3.2 mm thick white plate heat-treated glass for solar cells manufactured by Asahi Glass Co., Ltd.) as a cover material
  • 190 mm ⁇ 190 mm ethylene vinyl acetate (Sanvik sealing material 0.5 mm as a front side sealing material) Thickness)
  • strings with extraction electrodes that have been evaluated for power generation performance of a single cell
  • 190 mm x 190 mm ethylene vinyl acetate 0.5 mm thick sealant manufactured by Sunvic
  • 190 mm x 190 mm The film for solar cell backsheet of the present invention was stacked and fixed in order, and the glass was set so as to be in contact with the hot plate of the vacuum laminator, the hot plate temperature was 145 ° C., the vacuum was drawn for 4 minutes, the press was 1 minute, and the holding time.
  • the strings with extraction electrodes were set so that the glass surface was on the cell surface side.
  • the film for solar battery backsheets of this invention was a structure which has P2 layer on the single side
  • the obtained solar cell module was subjected to measurement of a short-circuit current measured according to the standard state of JIS C8914: 2005, and the power generation performance of the solar cell equipped with the solar cell backsheet of the present invention was obtained.
  • the adhesion of the solar cells was determined as follows by checking how many of the ten solar cells had the sheet peeled off visually. When peeling does not occur in all solar cells: A When the sheet is peeled from one or more than four solar cells among the produced solar cells: B When sheets are peeled from 4 or more and less than 8 solar cells among the produced solar cells: C When 8 or more sheets of the produced solar cells are peeled from the solar cells: D When peeling occurs in all solar cells: E Adhesiveness of the solar cell is good from A to D, and among them, A is the best.
  • Young's modulus When Young's modulus is 2.0 GPa or less: A When Young's modulus exceeds 2.0 GPa and is 3.0 GPa or less: B When Young's modulus is more than 3.0 GPa and 4.0 GPa or less: C When Young's modulus exceeds 4.0 GPa: D The Young's modulus is good from A to C, and A is the best among them.
  • the average value of the four curl heights obtained in step 1 was taken, and the curl height evaluation was determined as follows from the average value of the curl heights obtained.
  • the average curl height is less than 5 mm: A Average value of curl height is 5 mm or more and less than 10 mm: B The average curl height is 10 mm or more and less than 15 mm: C The average curl height is 15 mm or more: D The curl height is good in A to C, and A is the best among them.
  • Water vapor transmission rate is less than 0.5 g / m 2 / day: A Water vapor transmission rate is 0.5 g / m 2 / day or more and less than 1.0 g / m 2 / day: B Water vapor transmission rate is 1.0 g / m 2 / day or more and less than 2.0 g / m 2 / day: C Water vapor transmission rate is 2.0 g / m 2 / day or more and less than 3.0 g / m 2 / day: D Water vapor transmission rate is 3.0 g / m 2 / day or more: E The water vapor barrier properties A to D are good, and A is the best among them.
  • PET raw material A 100 parts by mass of dimethyl terephthalate, 57.5 parts by mass of ethylene glycol, 0.03 parts by mass of manganese acetate tetrahydrate and 0.03 parts by mass of antimony trioxide were melted at 150 ° C. in a nitrogen atmosphere. While stirring this melt, the temperature was raised to 230 ° C. over 3 hours to distill methanol, and the transesterification reaction was completed.
  • an ethylene glycol solution (pH 5.0) in which 0.005 parts by mass of phosphoric acid and 0.021 parts by mass of sodium dihydrogen phosphate dihydrate were dissolved in 0.5 parts by mass of ethylene glycol was added. .
  • the intrinsic viscosity of the polyester composition at this time was less than 0.2.
  • the polymerization reaction was performed at a final temperature of 285 ° C. and a degree of vacuum of 0.1 Torr to obtain polyethylene terephthalate having an intrinsic viscosity of 0.52 and a terminal carboxyl group amount of 15 equivalents / ton.
  • the obtained polyethylene terephthalate was dried and crystallized at 160 ° C. for 6 hours.
  • PET-a polyethylene terephthalate having an intrinsic viscosity of 0.82 and a terminal carboxyl group amount of 10 equivalents / ton.
  • the obtained polyethylene terephthalate composition had a glass transition temperature of 82 ° C. and a melting point of 255 ° C.
  • PET raw material B A polyethylene terephthalate (PET-b) having an intrinsic viscosity of 0.85 and a terminal carboxyl group amount of 6 equivalents / ton was obtained except that the solid phase polymerization time was 10 hours.
  • PET raw material C A polyethylene terephthalate (PET-c) having an intrinsic viscosity of 0.79 and a terminal carboxyl group content of 15 equivalents / ton was obtained except that the final temperature of the polymerization reaction was 290 ° C.
  • PET raw material D PET-d
  • PET-d polyethylene terephthalate
  • PET raw material E A polyethylene terephthalate (PET-e) having an intrinsic viscosity of 0.75 and a terminal carboxyl group content of 28 equivalents / ton was obtained except that the final temperature of the polymerization reaction was 300 ° C.
  • PET raw material F As the reaction catalyst, 0.03 parts by mass of magnesium acetate dihydrate instead of manganese acetate, and after completion of the transesterification reaction, the same procedure as in PET raw material A was performed except that only 0.005 parts by mass of phosphoric acid was added. Polyethylene terephthalate (PET-f) having a terminal carboxyl group amount of 10 equivalents / ton was obtained.
  • PET raw material G A polyethylene terephthalate (PET-g) having an intrinsic viscosity of 0.76 and a terminal carboxyl group content of 24 equivalents / ton was obtained except that the final temperature of the polymerization reaction was 297 ° C.
  • PET raw material H A polyethylene terephthalate (PET-h) having an intrinsic viscosity of 0.65 and a terminal carboxyl group amount of 34 equivalents / ton was obtained except that the final temperature of the polymerization reaction was 305 ° C.
  • Hollow nucleant master pellet B In place of PET resin A, 2. 6. Except for using the PET resin B obtained in the above section.
  • the hollow nucleating agent master pellet B was produced by the same composition and method as the hollow nucleating agent master pellet A of the item.
  • Hollow nucleant master pellet C In place of PET resin A, the above 3. 6. Except for using the PET resin C obtained in the above section.
  • the hollow nucleating agent master pellet C was produced by the same composition and method as the hollow nucleating agent master pellet A of the item.
  • Hollow core master pellet D In place of PET resin A, the above 4. 6. Except for using the PET resin D obtained in the above section.
  • the hollow nucleating agent master pellet D was produced by the same composition and method as the hollow nucleating agent master pellet A of the item.
  • Hollow core master pellet F In place of PET resin A, 5. 6. Except for using the PET resin F obtained in the above section.
  • the hollow nucleating agent master pellet F was produced by the same composition and method as the hollow nucleating agent master pellet A.
  • PMP polymethylpentene
  • TPX registered trademark
  • TPE polyester-based elastomer
  • Hytrel registered trademark
  • PET resin A PET-a
  • PP polypropylene
  • Noblen registered trademark
  • Titanium oxide master pellet 100 parts by mass of PET resin A (PET-a) obtained according to the above and 100 parts by mass of rutile-type titanium oxide particles (TiO 2 ) having an average particle diameter of 210 nm are melt-kneaded in a vented 290 ° C. extruder, and oxidized. A titanium master pellet was prepared.
  • Barium sulfate master pellet 100 parts by mass of PET resin A (PET-a) obtained according to the above and 100 parts by mass of barium sulfate particles (BaSO 4 ) having an average particle size of 1.5 ⁇ m were melt-kneaded in a vented 290 ° C. extruder, and sulfuric acid was added. Barium master pellets were prepared.
  • Polyethylene vinyl acetate copolymer film Polyethylene in which 50 parts by mass of polyethylene vinyl acetate (vinyl acetate content 5% by mass) and 30% by mass of titanium dioxide having a number average secondary particle size of 0.25 ⁇ m are dispersed as inorganic particles. 50 parts by mass of master chips (containing 30% by mass of titanium dioxide with respect to the total amount of master chips) were supplied to an extruder heated to a temperature of 190 ° C., and a polyethylene vinyl acetate film extruded from a T die was used.
  • PVF film “Tedlar” (registered trademark) manufactured by DuPont was used.
  • PVDF film Arkema “Kyner” (registered trademark) was used.
  • ETFE Film Daikin Industries, Ltd. “Neofluon” (registered trademark) EF series was used.
  • Urethane coating agent (coating agent a, coating agent b)
  • coating agent a “Halshybrit” (registered trademark) polymer UV-G301 (solid content concentration: 40), which is an acrylic coating agent manufactured by Nippon Shokubai Co., Ltd., is prepared according to the formulation shown in the main agent column of Table 9. (Mass%) were mixed together with colored pigment Titanium Co., Ltd. titanium oxide particles JR-709 and a solvent, and the mixture was dispersed using a bead mill.
  • polyester plasticizer “Polysizer” (registered trademark) W-220EL manufactured by DIC Corporation is added as a plasticizer to obtain a main component of coating agent a for resin layer formation having a solid content concentration of 51 mass%. It was.
  • “Desmodur” (registered trademark) N3300 (solid content concentration: 100 mass%) manufactured by Sumika Bayer Urethane Co., Ltd., which is a nurate-type hexamethylene diisocyanate resin shown in Table 10. Is added in an amount calculated in advance such that the mass ratio with the resin layer forming main agent is 100/4, and is further calculated in advance so that the solid content concentration is 20% by mass. Diluent: n-propyl acetate was weighed and stirred for 15 minutes to obtain a coating agent a having a solid concentration of 20% by mass.
  • coating agent b As preparation of coating agent b, “Takenate” (registered trademark) D120N manufactured by Mitsui Chemicals, Inc., which is a hydrogenated xylylene diisocyanate shown in Table 11, and “Zeffle” (registered trademark) GK570 manufactured by Daikin Industries, Ltd.
  • the diluent shown in Table 10 was blended in an amount calculated in advance so that the mass ratio to the resin layer forming main agent was 65/12, and further calculated in advance so that the solid content concentration was 20% by mass: N-Butyl acetate was weighed and stirred for 15 minutes to obtain a coating agent b having a solid content of 20% by mass.
  • Laminating adhesive As a laminating adhesive, 36 parts by mass of a dry laminating agent “Dick Dry” (registered trademark) TAF-300 manufactured by DIC Corporation, and a TAF hardener manufactured by DIC Corporation containing hexamethylene diisocyanate resin as a main component as a curing agent. 3 parts by weight of AH-3 and 30 parts by weight of ethyl acetate were weighed and stirred for 15 minutes to obtain a coating agent c as a laminating adhesive having a solid content concentration of 30% by weight.
  • a dry laminating agent “Dick Dry” registered trademark
  • TAF hardener manufactured by DIC Corporation containing hexamethylene diisocyanate resin as a main component as a curing agent.
  • 3 parts by weight of AH-3 and 30 parts by weight of ethyl acetate were weighed and stirred for 15 minutes to obtain a coating agent c as a laminating adhesive having a solid content concentration of 30% by weight.
  • Example 1 In order to obtain the composition shown in Table 1, 77.5 parts by mass of PET raw material A (PET-a) vacuum-dried at 180 ° C. for 2 hours as a raw material constituting the P1 layer and 22.5 parts of the hollow nucleating agent master pellet A were obtained. On the other hand, 72 parts by mass of PET raw material A (PET-a) vacuum-dried at 180 ° C. for 2 hours as a raw material constituting the P2 layer and 28 parts by mass of titanium oxide master pellets were mixed, Each was melted and discharged in two different extruders heated to 280 ° C., merged so as to be laminated with P2 / P1 / P2 in a feed block, and then co-extruded from a T die.
  • the co-extruded molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 50 ° C. to obtain an unstretched sheet.
  • a three-fold speed difference is created between the roll heated to a temperature of 88 ° C. and the roll adjusted to a temperature of 25 ° C.
  • the tenter is guided to a preheating zone at a temperature of 80 ° C. in the tenter, and subsequently in a heating zone maintained at 90 ° C. in a direction perpendicular to the longitudinal direction (width) Direction). Subsequently, heat treatment was carried out at 220 ° C. for 20 seconds in a heat treatment zone in the tenter, and further uniformly cooled while performing relaxation treatment in the 4% width direction to form a polyester film.
  • the overall porosity was 21%
  • the porosity of the surface layer was 2.5% for both Ps and Ps ′
  • the cavity area ratio was confirmed ( Both (Sc / Scs) and (Sc / Scs') were 3.5.
  • the polymer properties were measured, the intrinsic viscosity IV was 0.70 dl / g, the terminal carboxyl group amount was 14 equivalents / ton, and the metal elements contained 69 ppm of Mn, 241 ppm of Sb, and 29 ppm of Na.
  • the film had excellent adhesion, wet heat resistance, ultraviolet resistance, and thermal conductivity. Furthermore, as a result of evaluating the characteristics of the solar cell, it was found that it has excellent output improvement and adhesion.
  • Examples 2 to 11 Except for changing the composition of the P1 layer as shown in Table 1, using the amount of the hollow nucleating agent master pellet and the hollow nucleating agent master pellets G to I, or mixing the titanium oxide master pellet used in the P2 layer with the P1 layer. Obtained the film for solar cell backsheets similarly to Example 1.
  • Example 12 As shown in Table 3, a solar cell backsheet film was obtained in the same manner as in Example 1 except that the PET resin as the main component of the P1 layer and the P2 layer was changed to PET-b to f as shown in Table 3.
  • Examples 12 to 15 are in a good range although the adhesion is inferior to that of Example 1. I understood it.
  • the heat and humidity resistance decreased with a decrease in intrinsic viscosity IV and an increase in the amount of terminal carboxyl groups. It was also found that the thermal conductivity was excellent as in Example 1.
  • the output improvement was reduced with the increase in the amount of terminal carboxyl groups as compared with Example 1, the adhesion was in a good range.
  • Example 16 is inferior to Example 1 in terms of the intrinsic viscosity and the amount of terminal carboxyl groups, the adhesion of the solar battery backsheet, the output improvement of the solar battery, and the adhesion are inferior, but it is in a good range. I understood.
  • Examples 17 to 25 A solar battery backsheet film was obtained in the same manner as in Example 1 except that the lamination ratio and film configuration of the solar battery backsheet, the amount of inorganic particles in the P2 layer, and the casting temperature were changed as shown in Table 3.
  • Example 25 was smaller than Example 1 in both (Sc / Scs) and (Sc / Scs').
  • the polymer characteristics were the same as in Example 1.
  • the thickness of the P1 layer was T1 ( ⁇ m), and the thickness of the P2 layer was T2 ( ⁇ m), the adhesiveness is inferior to that of Example 1 as (T1 / T2) ⁇ W2 increases when the concentration of inorganic particles contained in the resin composition constituting the P2 layer is W2 (mass%). It was found to be in a good range. Further, the ultraviolet resistance was lowered as the concentration of inorganic particles in the P2 layer was lowered. The thermal conductivity was excellent as in Example 1.
  • Example 25 has the adhesion of the solar cell back sheet which is very excellent similarly to Example 1, and the output improvement property and adhesion of a solar cell, a cavity nucleating agent adheres on a process roll at the time of film forming. I found out that
  • Example 26 As shown in Table 3, a solar cell backsheet film was obtained in the same manner as in Example 1 except that a high concentration of inorganic particles was added to the P1 layer in the P1 layer single film configuration.
  • Example 27 Since barium sulfate particles are used as the inorganic particles of the P2 layer, barium sulfate master pellets are used, and the discharge rate of the extruder is adjusted so that the lamination ratio (P2: P1: P2) of the polyester film is 1: 1: 1. Obtained the film for solar cell backsheets similarly to Example 3. When the cavity area ratio of the obtained solar cell backsheet film was confirmed, as shown in Table 4, both (Sc / Scs) and (Sc / Scs') were smaller than Example 3. About the obtained solar cell backsheet film, as a result of evaluating the solar cell backsheet characteristics, it was found that the film for the solar cell backsheet had good adhesion although it was inferior to Example 3. The thermal conductivity was excellent as in Example 1. Furthermore, as a result of evaluating the solar cell characteristics, it was found that the solar cell characteristics were inferior to those of Example 3 but had good adhesiveness, and there was no problem in terms of output improvement.
  • Example 28 As shown in Table 3, a solar cell backsheet film was obtained in the same manner as in Example 1 except that the PET resin as the main component of the P1 layer and the P2 layer was changed to PET-g as shown in Table 3.
  • Example 29 to 31 A film for a solar battery back sheet was obtained in the same manner as in Example 1 except that the line speed was changed during film formation and the total thickness of the film was changed as shown in Table 3.
  • Examples 32 to 44 Using the coating material c prepared as the laminating adhesive on one surface of the P2 layer of the film for solar battery backsheet obtained in Example 1, it was applied using a wire bar and at a temperature of 80 ° C. for 45 seconds. The dried adhesive layer was formed so that the thickness of the coating film after drying was 5.0 ⁇ m. Next, the functional layer B shown in Table 5 was laminated
  • Example 45 to 49 In the same manner as in Examples 32 to 44, the functional layer B shown in Table 6 was laminated on the adhesive layer and aged at a temperature of 40 ° C. for 3 days to obtain a solar cell backsheet.
  • the solar cell backsheets shown in Examples 45 to 49 had good adhesion, moist heat resistance, and ultraviolet resistance, and had a large Young's modulus and curl height, but had excellent water vapor barrier properties. . Moreover, it was excellent in the solar cell characteristic.
  • Examples 50 to 53 Using one of the P2 layers of the solar cell backsheet film obtained in Example 1, the thickness of the functional layer B after drying becomes the thickness shown in Table 6, using a wire bar according to Table 6, and paint a The coating material b was applied and dried at a temperature of 100 ° C. for 60 seconds to produce solar cell backsheet films (in Examples 50 to 53, porosity, (Sc / Scs), (Sc / Scs) ') was determined based on a laminated film including the functional layer B). When the obtained solar cell backsheet film was evaluated as a solar cell backsheet, both the backsheet characteristics and the solar cell characteristics were excellent.
  • Example 54 Using the coating material c prepared as the laminating adhesive on one surface of the P2 layer of the film for solar battery backsheet obtained in Example 1, it was applied using a wire bar and at a temperature of 80 ° C. for 45 seconds. The dried adhesive layer was formed so that the thickness of the coating film after drying was 5.0 ⁇ m. Next, the functional layer B ′ shown in Table 6 was laminated on the adhesive layer and aged at a temperature of 40 ° C. for 3 days. Furthermore, using the coating material c prepared as a laminating adhesive on the other P2 layer on which the functional layer B ′ is not laminated, it is applied using a wire bar, dried at a temperature of 80 ° C.
  • the adhesive layer for lamination was formed so that the thickness of the coating film was 5.0 ⁇ m.
  • the functional layer B shown in Table 6 was laminated on the laminating adhesive layer and aged at a temperature of 40 ° C. for 3 days to obtain a solar cell backsheet.
  • the obtained solar cell backsheets shown in Examples 54 and 55 had good adhesion, wet heat resistance, and ultraviolet resistance, and were excellent in Young's modulus, curl height, and water vapor barrier properties. Moreover, it was excellent in the solar cell characteristic.
  • Example 56 Using one of the P2 layers of the solar cell backsheet film obtained in Example 1, the thickness of the functional layer B after drying becomes the thickness shown in Table 6, using a wire bar according to Table 6, and paint a Was applied and dried at a temperature of 100 ° C. for 60 seconds to obtain a solar battery backsheet film having a functional layer B. Further, using a coating c prepared as a laminating adhesive on one P2 layer on which the functional layer B is not laminated, it is applied using a wire bar, dried at a temperature of 80 ° C. for 45 seconds, and dried. The adhesive layer for lamination was formed so that the film thickness was 5.0 ⁇ m.
  • a functional layer B ′ shown in Table 6 was laminated on the laminating adhesive layer and aged at a temperature of 40 ° C. for 3 days to obtain a solar cell backsheet.
  • the solar cell back sheet shown in Example 56 was excellent in water vapor barrier property, although Young's modulus and curl height were large. Moreover, the solar cell characteristics were also excellent.
  • Example 1 A solar cell backsheet film was obtained in the same manner as in Example 1 except that the amount of the hollow nucleating agent in the P1 layer was 3% by mass. When the porosity of the obtained film for solar battery back sheets was confirmed, it was found that the porosity of the entire film was 9%, which was out of the scope of the present invention. Furthermore, it turned out that the film for solar cell backsheets obtained by the comparative example 1 is a solar cell backsheet inferior in adhesiveness and heat conductivity. Moreover, it turned out that it is a solar cell inferior to an output improvement property and adhesiveness also about a solar cell characteristic.
  • the solar cell backsheet films obtained in Comparative Examples 1 to 4 were solar cell backsheets having poor adhesion.
  • the comparative example 6 is a solar cell backsheet with inferior thermal conductivity.
  • the solar cell backsheet film was found to be a solar cell backsheet with poor adhesion and thermal conductivity. Moreover, it turned out that it is a solar cell inferior to an output improvement property and adhesiveness also about a solar cell characteristic.
  • Example 8 A solar cell backsheet film was obtained in the same manner as in Example 1 except that the PET resin, which is the main component of the P1 layer and P2 layer, was changed to PET-h.
  • the film for solar cell backsheets obtained by the comparative example 8 is a solar cell backsheet inferior in adhesiveness and heat-and-moisture resistance. Moreover, it turned out that it is a solar cell in which both an output improvement property and adhesiveness are inferior also about the solar cell characteristic.
  • Comparative Example 9 Pre-heated unstretched sheet obtained by extruding and cooling from a T-die with a P1 layer single-layer structure during film formation with a roll group heated to a temperature of 70 ° C, and then placed at a position 15 mm away from both surfaces of the sheet A solar cell backsheet film was obtained in the same manner as in Comparative Example 2, except that the film was heated for 0.72 seconds at an output of 50 W / cm with the infrared heater and stretched three times in the longitudinal direction (longitudinal direction). When the cavity area ratio of the obtained solar cell backsheet film was confirmed, unlike Comparative Example 2, the cavity area in the thickness direction was biased.
  • the average area per cavity is only small, and at a depth of 25 to 75% of the total film thickness, there is a difference in the average area per cavity.
  • (Sc / Scs) and (Sc / Scs ′) were 1.0.
  • the film for solar battery back sheet obtained in Comparative Example 9 was found to be a solar battery back sheet having poor adhesion. Moreover, it turned out that it is a solar cell in which both an output improvement property and adhesiveness are inferior also about the solar cell characteristic.
  • Example 10 A solar battery back sheet was laminated in the same manner as in Example 32 except that the film for Comparative Example 6 was used, and the functional layer B shown in Table 9 was laminated and aged at a temperature of 40 ° C. for 3 days. did.
  • the obtained solar cell back sheet was inferior in Young's modulus and curl height.
  • the solar cell characteristic although adhesiveness was improved from the comparative example 6, it was a solar cell with inferior output improvement.
  • Example 11 A solar battery back sheet was laminated in the same manner as in Example 42 except that the film of Comparative Example 6 was used, and the functional layer B shown in Table 9 was laminated and aged at a temperature of 40 ° C. for 3 days. did.
  • the obtained solar cell back sheet was inferior in Young's modulus and curl height. Moreover, it was a solar cell inferior to adhesiveness and output improvement about a solar cell characteristic.
  • the solar cell backsheet film of the present invention By mounting the solar cell backsheet film of the present invention on a solar cell as a solar cell backsheet, adhesion to the solar cell backsheet even when placed outdoors for a long period of time compared to conventional solar cells Can be maintained, and the power generation efficiency can be increased.
  • the solar cell of the present invention can be suitably used for various applications without being limited to outdoor use and indoor use such as a solar power generation system and a power source for small electronic components.

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CN107553999A (zh) * 2017-09-08 2018-01-09 乐凯胶片股份有限公司 一种pet片材及其应用
CN108732877A (zh) * 2017-04-18 2018-11-02 佳能株式会社 电子照相感光构件、处理盒、和电子照相设备

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CN110079223A (zh) * 2019-05-15 2019-08-02 王崧 一种高粘附、低透水的光伏电池组件封装用eva胶膜

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