WO2017094354A1 - Method for manufacturing solar cell sealing material and composition for manufacturing solar cell sealing material - Google Patents

Method for manufacturing solar cell sealing material and composition for manufacturing solar cell sealing material Download PDF

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WO2017094354A1
WO2017094354A1 PCT/JP2016/080103 JP2016080103W WO2017094354A1 WO 2017094354 A1 WO2017094354 A1 WO 2017094354A1 JP 2016080103 W JP2016080103 W JP 2016080103W WO 2017094354 A1 WO2017094354 A1 WO 2017094354A1
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ethylene
solar cell
olefin copolymer
sealing material
kpa
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PCT/JP2016/080103
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French (fr)
Japanese (ja)
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晃 吉武
央尚 片岡
欣将 深川
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株式会社ブリヂストン
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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
    • 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
    • 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 method for producing a solar cell encapsulant, a composition for producing a solar cell encapsulant, a solar cell encapsulant formed using the solar cell encapsulant, and a solar cell module.
  • a surface side transparent protective member 11 made of a glass substrate or the like, a surface side sealing material 13A, a solar cell element 14 such as a silicon crystal cell, a back side sealing
  • a stopper 13B and a back surface side protection member (back cover) 12 are laminated in this order and bonded and integrated.
  • connection tabs 15 in order to obtain a high electric output. Therefore, in order to ensure the insulation of the solar cell element 14, the solar cell element 14 is sealed using the insulating sealing materials 13A and 13B.
  • an ethylene-vinyl acetate copolymer (EVA) film having high transparency and adhesiveness has been conventionally used.
  • EVA film for the sealing material is blended with a crosslinking agent such as an organic peroxide in addition to EVA, and the EVA in the EVA film is manufactured at the time of manufacturing the solar cell module. Is generally crosslinked.
  • EVA contains vinyl acetate as a constituent component
  • acid is generated in the solar cell sealing material and corrosion of the electrodes of the solar cell module occurs. Therefore, an ethylene / ⁇ -olefin copolymer that does not generate an acid has recently attracted attention as a polymer that can replace EVA (for example, Patent Document 1).
  • an object of the present invention is to provide a solar cell encapsulant capable of producing a solar cell encapsulant having good workability during production of the solar cell encapsulant and having a good surface appearance. It is to provide a manufacturing method. Moreover, the objective of this invention is providing the composition for solar cell sealing material manufacture with favorable workability and the external appearance of the surface of the solar cell sealing material manufactured.
  • Another object of the present invention is to provide a solar cell encapsulant formed by molding the composition for producing a solar cell encapsulant and a solar cell obtained by encapsulating a solar cell element with the solar cell encapsulant. To provide a module.
  • the above object is a method for producing a sealing film for a solar cell comprising a mixture of two ethylene / ⁇ -olefin copolymers A and B having different melt flow rates (MFR),
  • MFR melt flow rates
  • the gel fraction of the ethylene / ⁇ -olefin copolymer A having an MFR (conforming to JIS K7210, measured at a temperature of 190 ° C. and a load of 2.16 kg, the same applies hereinafter) of 2 to 5 g / 10 min does not increase.
  • a molecular chain linking step to obtain an ethylene / ⁇ -olefin copolymer A ′ having a viscosity of 550 to 5000 kPa ⁇ s; By mixing the ethylene / ⁇ -olefin copolymer A ′ with the ethylene / ⁇ -olefin copolymer B having an MFR of 20 to 50 g / 10 min, the elongational viscosity at 80 ° C.
  • a mixing step of obtaining a composition for producing a solar cell encapsulant having a storage elastic modulus at °C (measured in accordance with JIS K7244 under the conditions of a strain of 10% and a frequency of 1 Hz; the same shall apply hereinafter);
  • a molding step of obtaining the solar cell sealing material by molding the composition for manufacturing the solar cell sealing material into a sheet shape; It is achieved by the manufacturing method of the sealing material for solar cells containing.
  • the two ethylene / ⁇ -olefin copolymers having the predetermined MFR are used, and the ethylene / ⁇ -olefin copolymer A having the lower MFR is subjected to a molecular chain linking reaction.
  • the elongation viscosity can be significantly increased without excessively increasing the elasticity of the solar cell encapsulant manufacturing composition, resulting in sheet breakage or sagging during the production of the solar cell encapsulant.
  • the processability is improved, and the appearance of the produced solar cell encapsulant is also improved.
  • the preferable aspect of the manufacturing method of the sealing material for solar cells of this invention is as follows.
  • the molecular chain linking step is performed by adding an organic peroxide to the ethylene / ⁇ -olefin copolymer A and then heating to decompose the organic peroxide.
  • the heating is performed by heating during mixing of the ethylene / ⁇ -olefin copolymer A and the organic peroxide.
  • the molecular chain linking step is performed by irradiating the ethylene / ⁇ -olefin copolymer A with ionizing radiation.
  • the transparency of the produced solar cell encapsulant is also good.
  • the molding step is performed by calendar molding.
  • the above object is to provide an ethylene / ⁇ -olefin copolymer A ′ having an elongation viscosity at 80 ° C. in a molten state of 550 to 5000 kPa and an MFR of 0.1 to 3.5 g / 10 min, and an MFR of 20 to A sealing for solar cells comprising a resin mixture with an ethylene / ⁇ -olefin copolymer B of 50 g / 10 min, an elongational viscosity at 80 ° C. of 100 kPa ⁇ s or more and a storage elastic modulus at 80 ° C. of 40 kPa or less It is also achieved by a composition for manufacturing a material.
  • the preferable aspect of the sealing material for solar cells of this invention is as follows. (1)
  • the elongation viscosity at 80 ° C. of the ethylene / ⁇ -olefin copolymer B is 0.01 to 50 kPa ⁇ s.
  • the content of the ethylene / ⁇ -olefin copolymer A ′ is 10 to 75 parts by mass based on 100 parts by mass of the total amount of the ethylene / ⁇ -olefin copolymer A ′ and B,
  • the content of ⁇ -olefin copolymer B is 25 to 90 parts by mass.
  • the present invention is a solar cell module comprising a solar cell and a surface side protective member, a solar cell element and a back side protective member, wherein the composition for producing a solar cell encapsulant is formed into a sheet shape,
  • a solar cell module in which a solar cell element is sealed with the solar cell sealing material of the present invention.
  • the composition for producing a solar cell encapsulant according to the present invention has good processability, and the produced solar cell encapsulant has an excellent appearance. Therefore, it is possible to stably and efficiently manufacture a solar cell sealing material having excellent appearance.
  • the method for producing a solar cell encapsulant of the present invention is also referred to as an ethylene / ⁇ -olefin copolymer A (hereinafter simply referred to as “copolymer A”) having an MFR of 2 to 5 g / min. )
  • copolymer A having an MFR of 2 to 5 g / min.
  • copolymer B having an MFR of 20 to 50 g / 10 min.
  • the molecular chain linking step of the ethylene / ⁇ -olefin copolymer A can be performed using an organic peroxide or ionizing radiation.
  • an organic peroxide is added to the ethylene / ⁇ -olefin copolymer A, and the organic peroxide is decomposed by heating to generate radicals.
  • -It is carried out by connecting the molecular chains of the olefin copolymer A together.
  • the amount of the organic peroxide added is preferably 0.05 to 0.125 parts by mass, more preferably 0.08 to 0.12 parts by mass with respect to 100 parts by mass of the ethylene / ⁇ -olefin copolymer A.
  • the organic peroxide that can be used can be the same as the organic peroxide described later that is used for cross-linking during modularization when manufacturing the solar cell module.
  • the molecular chain linking reaction is preferably performed by heating when an organic peroxide is added to the ethylene / ⁇ -olefin copolymer A and mixed.
  • the heating temperature at this time may be higher than the temperature at which the organic peroxide is decomposed, but is, for example, 160 to 200 ° C.
  • the molecular chain linking reaction may be performed by irradiating the ethylene / ⁇ -olefin copolymer A with ionizing radiation. Irradiation with ionizing radiation is performed so that the 80 ° C. extensional viscosity is in the range described below within a range where the gel fraction of the copolymer A does not increase.
  • ionizing radiation electron beams, ⁇ rays, ⁇ rays, ⁇ rays, neutron rays and the like can be used, and among them, ⁇ rays are preferable.
  • the irradiation intensity of the ionizing radiation may be set so that the 80 ° C. extensional viscosity of the ethylene / ⁇ -olefin copolymer A falls within the following range, for example, 5 to 15 kGy.
  • the shape of the ethylene / ⁇ -olefin copolymer at the time of irradiation is not particularly limited, and may be a pellet or the like.
  • the transparency (light transmittance and haze) of the solar cell encapsulant to be produced is better than that by the organic peroxide.
  • the gel fraction does not increase.
  • the phrase “the gel fraction does not increase” means that the gel fraction is 0% before and after the molecular chain linking reaction.
  • the 80 ° C. extensional viscosity of the ethylene / ⁇ -olefin copolymer A ′ after the molecular chain linking reaction is 550 to 5000 kPa ⁇ s. When the 80 ° C.
  • extensional viscosity is less than 550 kPa ⁇ s, when mixed with the ethylene / ⁇ -olefin copolymer B, the elongation viscosity at 80 ° C. of the composition for producing a sealing material for solar cells does not increase, and the workability decreases. . If it is greater than 5000 kPa ⁇ s, gels (grains) are always generated even when mixed, and the appearance of the solar cell encapsulant as a product is degraded.
  • the molecular chain linking reaction is preferably carried out so as to be in the range of 550 to 3000 kPa ⁇ s, more preferably 800 to 2700 kPa ⁇ s.
  • reaction product After completion of the molecular chain linking reaction, the reaction product is cooled, pelletized as appropriate, and may be subjected to the next mixing step, or may be directly mixed with the ethylene / ⁇ -olefin copolymer B in the next mixing step. May be.
  • the mixing step the ethylene / ⁇ -olefin copolymer A ′ having undergone the molecular chain linking reaction is converted into an ethylene / ⁇ -olefin copolymer B having an MFR of 20 to 50 g / 10 min, and additives described later as necessary.
  • Mixing can be performed by a normal method such as a roll mill.
  • the temperature at the time of mixing may be at least the melting point of the ethylene / ⁇ -olefin copolymers A ′ and B, and is, for example, 60 to 100 ° C.
  • This composition for producing a sealing material for a solar cell has an elongational viscosity at 80 ° C. (viscosity when the Henky strain is 1.0 under the condition of a strain rate of 0.05 / s. The same applies hereinafter).
  • S or more preferably 100 to 2000 kPa ⁇ s, more preferably 100 to 1000 kPa ⁇ s, still more preferably 100 to 500 kPa ⁇ s, and storage elastic modulus at 80 ° C. (strain amount 10% in accordance with JIS K7244) , Measured at a frequency of 1 Hz.
  • the mixing ratio of the ethylene / ⁇ -olefin copolymers A ′ and B is sufficient if the 80 ° C. storage elastic modulus and 80 ° C. elongation viscosity of the composition for producing a solar cell encapsulant are within the above ranges. -It can be appropriately changed according to the 80 ° C elongation viscosity of the olefin copolymer A '.
  • the ethylene / ⁇ -olefin copolymer A ′ and B have a total mass of 100 parts by mass, and the ethylene / ⁇ -olefin copolymer A ′ content is 10 to 75 parts by mass.
  • the content of the olefin copolymer B is preferably 25 to 90 parts by mass.
  • the content of the ethylene / ⁇ -olefin copolymer A ′ is 20 to 50 parts by mass with respect to 100 parts by mass of the total mass of the ethylene / ⁇ -olefin copolymers A ′ and B,
  • the content of ⁇ -olefin copolymer B is preferably 50 to 80 parts by mass.
  • the content of the ethylene / ⁇ -olefin copolymer A ′ is 20 to 40 parts by mass with respect to 100 parts by mass of the total mass of the ethylene / ⁇ -olefin copolymers A ′ and B
  • the content of ⁇ -olefin copolymer B is preferably 60 to 80 parts by mass.
  • the solar cell encapsulant manufacturing composition is formed into a sheet shape to obtain a solar cell encapsulant.
  • the molding method is not particularly limited, and it can be produced by a method of obtaining a sheet by molding by ordinary extrusion molding, calendar molding (calendering) or the like.
  • the thickness of the solar cell encapsulant is not particularly limited, but is 0.05 to 2 mm, preferably 0.3 to 0.8 mm, and more preferably 0.4 to 0.7 mm.
  • the method for producing the solar cell sealing material of the present invention is performed.
  • the two ethylene / ⁇ -olefin copolymers A and B having the predetermined MFR are used, and the ethylene / ⁇ -olefin copolymer A having the lower MFR is subjected to a molecular linking reaction. .
  • the elongation viscosity can be significantly increased without excessively increasing the elasticity of the solar cell encapsulant manufacturing composition, resulting in sheet breakage or sagging during the production of the solar cell encapsulant.
  • the processability is improved, and the appearance of the produced solar cell encapsulant is also improved.
  • the MFR of the ethylene / ⁇ -olefin copolymer A (before the molecular chain linking reaction) is 2 to 5 g / 10 min. If the MFR is less than 2 g / 10 min, the fluidity is too low to be mixed well and the appearance deteriorates. On the other hand, if the MFR is larger than 5 g / 10 min, the crosslinking effect is not so much. It is preferably 2 to 4 g / 10 min. On the other hand, the MFR of the ethylene / ⁇ -olefin copolymer B is 20 to 50 g / 10 min.
  • the MFR is less than 20 g / 10 min, the appearance is not improved. Moreover, when MFR is larger than 50 g / 10 min, it becomes difficult to mix. It is preferably 25 to 40 g / 10 min, more preferably 27 to 35 g / 10 min.
  • the MFR of the ethylene / ⁇ -olefin copolymer A ′ (after the molecular chain linking reaction) is lower than that of the copolymer A, for example, 0.1 to 3.5 g / 10 min, preferably 0.5 to 2.5 g. / 10 min.
  • the difference in density between the ethylene / ⁇ -olefin copolymers A and A ′ and B is preferably less than 0.01 g / cm 3 . Further, the difference in melting point between the ethylene / ⁇ -olefin copolymers A and A ′ and B is preferably less than 10 ° C. Thereby, the composition for solar cell sealing film manufacture which is further excellent in external appearance property and workability can be obtained.
  • the density of the ethylene / ⁇ -olefin copolymers A and A ′ and B is preferably 0.86 to 0.90 g / cm 3 , and 0.875 to 0.885 g / cm 3 . It is particularly preferred.
  • the density of ethylene- ⁇ -olefins A and B is a value determined according to JIS K 7112.
  • the melting points of the ethylene / ⁇ -olefin copolymers A and A ′ and B are preferably 50 to 80 ° C., and more preferably 50 to 70 ° C.
  • the melting points of the ethylene / ⁇ -olefin copolymers A and B are melting peak temperatures in a DSC curve obtained by heat flux differential scanning calorimetry according to JIS K7121.
  • the elongation viscosity at 80 ° C. of the ethylene / ⁇ -olefin copolymer A in the molten state before the molecular chain linking reaction is generally 50 to 200 kPa ⁇ s.
  • the elongation viscosity at 80 ° C. in the molten state of the ethylene / ⁇ -olefin copolymer A ′ after the molecular chain linking reaction is 550 to 5000 kPa ⁇ s as described above.
  • the elongation viscosity at 80 ° C. of the copolymer A ′ is preferably 2.5 to 100 times that of the copolymer A.
  • the height viscosity of copolymer B at 80 ° C. is preferably 0.01 to 50 kPa ⁇ s, more preferably 0.01 to 10 kPa.
  • the difference in refractive index between the ethylene / ⁇ -olefin copolymer A ′ and B is preferably 0.001 or less from the viewpoint of improving the transparency of the solar cell encapsulant.
  • the ethylene / ⁇ -olefin copolymers A and B are composed mainly of structural units derived from ethylene and further have an ⁇ -olefin having 3 to 12 carbon atoms, such as propylene, 1-butene, 1-hexene, and 1-octene. , Ethylene- ⁇ -olefin copolymer having one or more structural units derived from 4-methylpentene-1, 4-methyl-hexene-1, 4,4-dimethyl-pentene-1, etc. (terpolymer) Etc.).
  • the ethylene / ⁇ -olefin copolymer examples include an ethylene / 1-butene copolymer, an ethylene / 1-octene copolymer, an ethylene-4-methyl-pentene-1 copolymer, an ethylene / butene / hexene copolymer. Center polymers, ethylene / propylene / octene terpolymers, ethylene / butene / octene terpolymers, and the like.
  • the content of ⁇ -olefin in the ethylene / ⁇ -olefin copolymer is preferably 5 to 40% by mass, more preferably 10 to 35% by mass, and still more preferably 15 to 30% by mass. If the ⁇ -olefin content is small, the solar cell encapsulant may not have sufficient flexibility and impact resistance, and if it is too much, the heat resistance may be low.
  • the ethylene / ⁇ -olefin copolymers A and B may be those polymerized using a Ziegler-Natta catalyst or a metallocene catalyst, and in particular, linear ethylene / ⁇ -olefin copolymers. Can be preferably used.
  • the molecular weight distribution Mw / Mn is preferably 2.0 to 3.5.
  • the ethylene / ⁇ -olefin copolymers A and B may be random copolymers or block copolymers, and are preferably random copolymers.
  • the ethylene / ⁇ -olefin copolymers A and B may be crystalline or amorphous, and preferably amorphous.
  • the composition for producing a sealing material for solar cells of the present invention preferably contains a crosslinking agent to form a crosslinked structure of the ethylene / ⁇ -olefin copolymers A and B.
  • a crosslinking agent an organic peroxide or a photopolymerization initiator is preferably used.
  • an organic peroxide because a sealing material with improved temperature dependency of adhesive strength, moisture resistance, and penetration resistance can be obtained.
  • Any organic peroxide may be used as long as it decomposes at a temperature of 100 ° C. or higher to generate radicals.
  • the organic peroxide is generally selected in consideration of the film formation temperature, the adjustment conditions of the composition, the curing temperature, the heat resistance of the adherend, and the storage stability. In particular, the one having a decomposition temperature of 70 ° C. or more with a half-life of 10 hours is preferable.
  • organic peroxide examples include, from the viewpoint of processing temperature and storage stability of the resin, for example, benzoyl peroxide curing agent, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, 3, 5, 5- Trimethylhexanoyl peroxide, di-n-octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, succinic acid peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethyl Peroxy-2-ethylhexanoate, tert-hexylpa Oxy-2-ethylhexano
  • benzoyl peroxide-based curing agent any can be used as long as it decomposes at a temperature of 70 ° C. or higher to generate radicals, and those having a decomposition temperature of 50 hours or higher with a half-life of 10 hours are preferable, It can be appropriately selected in consideration of preparation conditions, film formation temperature, curing (bonding) temperature, heat resistance of the adherend, and storage stability.
  • Usable benzoyl peroxide curing agents include, for example, benzoyl peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, p-chlorobenzoyl peroxide, m-toluoyl peroxide, 2, Examples include 4-dichlorobenzoyl peroxide and t-butyl peroxybenzoate.
  • the benzoyl peroxide curing agent may be used alone or in combination of two or more.
  • organic peroxide 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane or tert-butylperoxy-2-ethylhexyl monocarbonate is particularly preferable.
  • crosslinked favorably and has the outstanding transparency is obtained.
  • the content of the organic peroxide used in the composition for producing a sealing material for solar cells is preferably 0.1 to 5 with respect to 100 parts by mass of the total amount of the ethylene / ⁇ -olefin copolymers A and B. It is preferable that the amount is part by mass, more preferably 0.2 to 3 parts by mass. If the content of the organic peroxide is small, the crosslinking speed may be lowered during the crosslinking and curing, and if the content is large, the compatibility with the copolymer may be deteriorated.
  • photopolymerization initiator any known photopolymerization initiator can be used, but a photopolymerization initiator having good storage stability after blending is desirable.
  • photopolymerization initiators include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, and 2-methyl-1- (4- (methylthio) phenyl).
  • Acetophenones such as -2-morpholinopropane-1, benzoins such as benzyldimethylketal, benzophenones such as benzophenone, 4-phenylbenzophenone and hydroxybenzophenone, thioxanthones such as isopropylthioxanthone and 2-4-diethylthioxanthone, As other special ones, methylphenylglyoxylate can be used. Particularly preferably, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1, Examples include benzophenone.
  • photopolymerization initiators may contain one or more known photopolymerization accelerators such as benzoic acid-based or tertiary amine-based compounds such as 4-dimethylaminobenzoic acid, if necessary. Can be mixed and used. Moreover, it can be used individually by 1 type of only a photoinitiator, or 2 or more types of mixture.
  • the content of the photopolymerization initiator is 0.1 to 5 parts by mass, preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the total amount of the ethylene / ⁇ -olefin copolymers A and B.
  • the composition for manufacturing a sealing material for solar cells of the present invention further contains a crosslinking aid.
  • the crosslinking aid can improve the gel fraction of the ethylene / ⁇ -olefin copolymers A and B and improve the adhesion and weather resistance of the solar cell encapsulant.
  • the content of the crosslinking aid is usually 0.1 to 5 parts by mass, preferably 0.1 to 3 parts by mass, particularly preferably 100 parts by mass of the total amount of the ethylene / ⁇ -olefin copolymers A and B. Is used at 0.5 to 2.5 parts by mass. Thereby, the sealing material which the hardness after bridge
  • crosslinking aid compound having a radical polymerizable group as a functional group
  • examples of the crosslinking aid include trifunctional crosslinking aids such as triallyl cyanurate and triallyl isocyanurate, and (meth) acrylic esters (eg, NK ester) ) Monofunctional or bifunctional crosslinking aids.
  • trifunctional crosslinking aids such as triallyl cyanurate and triallyl isocyanurate, and (meth) acrylic esters (eg, NK ester) ) Monofunctional or bifunctional crosslinking aids.
  • triallyl cyanurate and triallyl isocyanurate are preferable, and triallyl isocyanurate is particularly preferable.
  • the composition for producing a sealing material for solar cell of the present invention may further contain an adhesion improver.
  • an adhesion improver a silane coupling agent can be used. Thereby, it can be set as the sealing material for solar cells which has the further outstanding adhesive force.
  • the silane coupling agent include ⁇ -chloropropyltrimethoxysilane, vinyltriethoxysilane, vinyltris ( ⁇ -methoxyethoxy) silane, ⁇ -methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, and ⁇ -glycidoxypropyl.
  • the content of the silane coupling agent in the composition for producing a solar cell sealing material of the present invention is 5 parts by mass or less, preferably 100 parts by mass of the total amount of ethylene / ⁇ -olefin copolymers A and B, preferably The amount is preferably 0.1 to 2 parts by mass.
  • composition for producing a sealing material for solar cells of the present invention improves or adjusts various physical properties of a film (optical properties such as mechanical strength and transparency, heat resistance, light resistance, crosslinking speed, etc.), especially a machine.
  • Various additives such as a plasticizer, an acryloxy group-containing compound, a methacryloxy group-containing compound, and / or an epoxy group-containing compound may be further included as necessary for improving the mechanical strength.
  • the structure of the solar cell module of the present invention is not particularly limited as long as it includes a structure manufactured by sealing a solar cell element using the solar cell sealing material of the present invention.
  • a solar cell element single crystal or polycrystalline silicon cell or the like
  • Examples include a sealed structure.
  • front side the side of the solar cell element irradiated with light
  • back side the side opposite to the light receiving surface of the solar cell element
  • the front surface side transparent protective member 11 the front surface side sealing material 13A, the solar cell element 14, the back surface side sealing material 13B.
  • the back surface side protection member 12 is laminated
  • a laminated body in which each member is laminated is heated by a vacuum laminator at a temperature of 135 to 180 ° C., further 140 to 180 ° C., a degassing time of 0.1 to 5 minutes, and a press pressure of 0.1 to 1.
  • Heat pressing may be performed at 5 kg / cm 2 and a press time of 5 to 15 minutes.
  • the front surface side sealing material 13A and the back surface side sealing material 13B are sealed.
  • the solar cell element 14 can be sealed by integrating the front surface side transparent protective member 11, the back surface side transparent member 12, and the solar cell element 14 via the material 13B.
  • the solar cell elements 14 are electrically connected to each other by connection tabs 15.
  • the solar cell encapsulant of the present invention is not limited to a solar cell module using a single crystal or polycrystalline silicon crystal solar cell as shown in FIG. It can also be used as a sealing material for thin film solar cell modules such as solar cells and copper indium selenide (CIS) solar cells.
  • the solar cell of the present invention is formed on a thin film solar cell element layer formed by a chemical vapor deposition method or the like on the surface of a surface side transparent protective member such as a glass substrate, a polyimide substrate, or a fluororesin transparent substrate.
  • a structure that is bonded and integrated For example, a structure that is bonded and integrated.
  • a photovoltaic cell and a thin film solar cell element are named generically, and are called a solar cell element.
  • the surface side transparent protective member 11 is usually a glass substrate such as silicate glass.
  • the thickness of the glass substrate is generally from 0.1 to 10 mm, and preferably from 0.3 to 5 mm.
  • the glass substrate may generally be chemically or thermally strengthened.
  • the back side protective member 12 is preferably a plastic film such as polyethylene terephthalate (PET) or polyamide. Further, a film obtained by laminating a fluorinated polyethylene film, particularly a fluorinated polyethylene film / Al / fluorinated polyethylene film in this order in consideration of heat resistance and wet heat resistance may be used. Further, a glass plate may be used.
  • PET polyethylene terephthalate
  • a film obtained by laminating a fluorinated polyethylene film, particularly a fluorinated polyethylene film / Al / fluorinated polyethylene film in this order in consideration of heat resistance and wet heat resistance may be used. Further, a glass plate may be used.
  • the sealing material for solar cells of this invention has the characteristics in the sealing material used for the surface side and / or back surface side of a solar cell module (a thin film solar cell module is included). Therefore, members other than the sealing material such as the front surface side transparent protective member, the back surface side protective member, and the solar cell element may have the same configuration as that of a conventionally known solar cell module, and are not particularly limited.
  • molecular chain linking polymer (molecular chain linking step) (1) Preparation with organic peroxide (1-1) Molecular chain-linked polymer 1 to 3 Ethylene / ⁇ -olefin copolymer A (linear ethylene / ⁇ -olefin copolymer polymerized using metallocene catalyst, MFR: 3.5 g / 10 min, melting point: 60 ° C., density: 0.880 g / cm 3 (Kernel KS341T, manufactured by Nippon Polyethylene Co., Ltd.), random copolymer, amorphous) and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane as an organic peroxide in the following amounts It mix
  • the elongation viscosity at 80 ° C. of the ethylene / ⁇ -olefin copolymer A before the molecular chain linking reaction was 110 kPa ⁇ s.
  • the elongational viscosities of the molecular chain linked polymers 1 to 3 at 80 ° C. were 1500 kPa ⁇ s, 2200 kPa ⁇ s, and 3000 kPa ⁇ s, respectively.
  • the MFRs of the molecular chain linked polymers 1 to 3 were 1 g / 10 min, 0.7 g / 10 min, and 0.5 g / 10 min, respectively.
  • Molecular chain linking polymer 8 The ethylene / ⁇ -olefin copolymer A is converted into an ethylene / ⁇ -olefin copolymer D (a linear ethylene / ⁇ -olefin copolymer polymerized using a metallocene catalyst, MFR: 12 g / 10 min, melting point: Molecular chain-linked polymer 8 was obtained in the same manner as molecular chain-linked polymer 1, except that the temperature was changed to 60 ° C. and density: 0.88 g / cm 3 .
  • the elongation viscosity at 80 ° C. of the ethylene / ⁇ -olefin copolymer D before the molecular chain linking reaction was 6 kPa ⁇ s.
  • the elongational viscosity at 80 ° C. of the molecular chain linked polymer 8 was 500 kPa ⁇ s.
  • the elongation viscosity at 80 ° C. of the ethylene / ⁇ -olefin copolymer A before the molecular chain linking reaction was 110 kPa ⁇ s.
  • the elongational viscosities of the molecular chain linked polymers 4 to 6 at 80 ° C. were 1000 kPa ⁇ s, 2700 kPa ⁇ s, and 4500 kPa ⁇ s, respectively.
  • the MFRs of the molecular chain linked polymers 1 to 3 were 1.2 g / 10 min, 1 g / 10 min, and 0.9 g / 10 min, respectively.
  • the elongation viscosity at 80 ° C. of the ethylene / ⁇ -olefin copolymer C before the molecular chain linking reaction was 10 kPa ⁇ s.
  • the extensional viscosity at 80 ° C. of the molecular chain linked polymer 10 was 600 kPa ⁇ s.
  • the elongation viscosity at 80 ° C. of the ethylene / ⁇ -olefin copolymer D before the molecular chain linking reaction was 6 kPa ⁇ s.
  • the elongational viscosity at 80 ° C. of the molecular chain linked polymer 11 was 500 kPa ⁇ s.
  • the elongation viscosity at 80 ° C. of the ethylene / ⁇ -olefin copolymer E before the molecular chain linking reaction was 200 kPa ⁇ s.
  • the elongational viscosity at 80 ° C. of the molecular chain linked polymer 12 was 6000 kPa ⁇ s.
  • composition for producing solar cell encapsulant (mixing step) Each material was supplied to a roll mill with the composition shown in the following table, and kneaded at 80 ° C. to prepare a composition for producing a solar cell encapsulant.
  • Base polymer 1 linear ethylene / ⁇ -olefin copolymer polymerized using a metallocene catalyst (Kernel KS341T, manufactured by Nippon Polyethylene Co., Ltd., random copolymer, amorphous) MFR: 3.5g / 10min Melting point: 60 ° C Density: 0.880 g / cm 3 Elongation viscosity at 80 ° C: 110 kPa ⁇ s
  • Base polymer 2 Linear ethylene / ⁇ -olefin copolymer polymerized using a metallocene catalyst (Kernel KJ640T, manufactured by Nippon Polyethylene Co., Ltd., random copolymer, amorphous) ethylene / ⁇ -olefin copolymer As B MFR: 30g / 10min Melting point: 58 ° C Density: 0.880 g / cm 3 Elongation viscosity at 80 ° C: 0.03 kPa ⁇ s
  • Base polymer 3 linear ethylene / ⁇ -olefin copolymer polymerized using a metallocene catalyst MFR: 65 g / 10 min Melting point: 60 ° C Density: 0.88 g / cm 3 Elongation viscosity at 80 ° C: 0.01 kPa ⁇ s
  • Base polymer 4 linear ethylene / ⁇ -olefin copolymer polymerized using a metallocene catalyst MFR: 20 g / 10 min Melting point: 60 ° C Density: 0.88 g / cm 3 Elongation viscosity at 80 ° C: 0.1 kPa ⁇ s
  • Base polymer 5 linear ethylene / ⁇ -olefin copolymer polymerized using a metallocene catalyst MFR: 50 g / 10 min Melting point: 60 ° C Density: 0.88 g / cm 3 Elongation viscosity at 80 ° C: 0.01 kPa ⁇ s

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Abstract

Provided is a method for manufacturing a solar cell sealing material, by which a solar cell sealing material excellent in surface appearance can be manufactured with excellent processability when manufacturing the solar cell sealing material. The method for manufacturing a solar cell sealing material is for manufacturing a solar cell sealing film containing a mixture of two kinds of ethylene/α-olefin copolymers A and B having different melt flow rates (MFR), and comprises: a molecule chain linking step for causing linking reaction between molecules of the ethylene/α-olefin copolymer A, which has an MFR (measured under a condition where the temperature is 190°C and the load is 2.16 kg in accordance with JIS K7210, the same applies hereafter) of 2-5 g/10 min, within a range where the gel fraction thereof is not increased, to obtain an ethylene/α-olefin copolymer A' having an elongational viscosity (a viscosity when a Hencky strain is 1.0 under a condition where a rate of distortion is 0.05/s, the same applies hereafter) of 550-5000 kPa·s at 80°C, at which the copolymer is in the molten state; a mixing step for mixing the ethylene/α-olefin copolymers A' with the ethylene/α-olefin copolymer B, which has an MFR of 20-50 g/10 min, to obtain a composition for manufacturing a solar cell sealing material, the composition having an elongational viscosity of 100 kPa·s or higher at 80°C and having a storage elastic modulus (measured under a condition where the amount of distortion is 10% and the frequency is 1 Hz in accordance with JIS K7244, the same applies hereafter) of 40 kPa or lower at 80°C; and a molding step for molding, into a sheet-like shape, the composition for manufacturing a solar cell sealing material, to obtain a solar cell sealing material.

Description

太陽電池用封止材の製造方法及び太陽電池用封止材製造用組成物Method for producing solar cell encapsulant and composition for producing solar cell encapsulant
　本発明は太陽電池用封止材の製造方法、太陽電池用封止材製造用組成物、これを用いて形成された太陽電池用封止材及び太陽電池モジュールに関する。 The present invention relates to a method for producing a solar cell encapsulant, a composition for producing a solar cell encapsulant, a solar cell encapsulant formed using the solar cell encapsulant, and a solar cell module.
　近年、資源の有効利用や環境汚染の防止等の面から、太陽光を電気エネルギーに直接変換する太陽電池モジュールが広く使用され、更に、耐久性や発電効率等の点から開発が進められている。 In recent years, solar cell modules that directly convert sunlight into electrical energy have been widely used from the standpoints of effective use of resources and prevention of environmental pollution, and are being developed further in terms of durability and power generation efficiency. .
　太陽電池モジュールの構造としては、例えば、図１に示すように、ガラス基板等からなる表面側透明保護部材１１、表面側封止材１３Ａ、シリコン結晶系セル等の太陽電池素子１４、裏面側封止材１３Ｂ、及び裏面側保護部材（バックカバー）１２をこの順で積層し、接着一体化した構造が知られている。 As the structure of the solar cell module, for example, as shown in FIG. 1, a surface side transparent protective member 11 made of a glass substrate or the like, a surface side sealing material 13A, a solar cell element 14 such as a silicon crystal cell, a back side sealing There is known a structure in which a stopper 13B and a back surface side protection member (back cover) 12 are laminated in this order and bonded and integrated.
　太陽電池モジュールでは、高い電気出力を得るために、複数の太陽電池素子１４を接続タブ１５で接続して用いられている。したがって、太陽電池素子１４の絶縁性を確保するために、絶縁性のある封止材１３Ａ、１３Ｂを用いて太陽電池素子１４を封止している。 In the solar cell module, a plurality of solar cell elements 14 are connected by connection tabs 15 in order to obtain a high electric output. Therefore, in order to ensure the insulation of the solar cell element 14, the solar cell element 14 is sealed using the insulating sealing materials 13A and 13B.
　これらの太陽電池モジュールに用いられる封止材としては、高い透明性及び接着性を有するエチレン－酢酸ビニル共重合体（ＥＶＡ）フィルムが従来から用いられている。そして、封止材用のＥＶＡフィルムには、膜強度や耐久性を向上させるために、ＥＶＡの他に有機過酸化物等の架橋剤が配合され、太陽電池モジュールの製造時にＥＶＡフィルム中のＥＶＡを架橋させるのが一般的である。 As a sealing material used in these solar cell modules, an ethylene-vinyl acetate copolymer (EVA) film having high transparency and adhesiveness has been conventionally used. In order to improve the film strength and durability, the EVA film for the sealing material is blended with a crosslinking agent such as an organic peroxide in addition to EVA, and the EVA in the EVA film is manufactured at the time of manufacturing the solar cell module. Is generally crosslinked.
　ところが、ＥＶＡは構成成分として酢酸ビニルを含むため、太陽電池用封止材中に酸が発生し、太陽電池モジュールの電極の腐食を発生させるという問題がある。そのため、ＥＶＡに代わるポリマーとして、酸が発生しないエチレン・α－オレフィン共重合体が近年注目を集めている（例えば、特許文献１）。 However, since EVA contains vinyl acetate as a constituent component, there is a problem in that acid is generated in the solar cell sealing material and corrosion of the electrodes of the solar cell module occurs. Therefore, an ethylene / α-olefin copolymer that does not generate an acid has recently attracted attention as a polymer that can replace EVA (for example, Patent Document 1).
特開２０１２－２５９４５号公報JP 2012-25945 A
　しかしながら、エチレン・α－オレフィン共重合体を用いて太陽電池用封止材を製造するとその表面が荒れ、外観が悪化しやすいという問題があった。また、エチレン・α－オレフィン共重合体を用いると太陽電池封止材の成形時にシート切れやダレが生じ、加工性が低下する場合がある。 However, when a solar cell encapsulant is produced using an ethylene / α-olefin copolymer, there is a problem that the surface becomes rough and the appearance tends to deteriorate. In addition, when an ethylene / α-olefin copolymer is used, the sheet may be cut or sag during molding of the solar cell encapsulant, which may reduce workability.
　したがって、本発明の目的は、太陽電池用封止材の製造時における加工性が良好であり、表面の外観が良好な太陽電池用封止材を製造することができる太陽電池用封止材の製造方法を提供することにある。また、本発明の目的は、加工性が良好であり、製造される太陽電池用封止材の表面の外観が良好となる太陽電池用封止材製造用組成物を提供することにある。 Accordingly, an object of the present invention is to provide a solar cell encapsulant capable of producing a solar cell encapsulant having good workability during production of the solar cell encapsulant and having a good surface appearance. It is to provide a manufacturing method. Moreover, the objective of this invention is providing the composition for solar cell sealing material manufacture with favorable workability and the external appearance of the surface of the solar cell sealing material manufactured.
　また、本発明の目的は、この太陽電池用封止材製造用組成物を成形してなる太陽電池用封止材及びこの太陽電池用封止材により太陽電池素子を封止してなる太陽電池モジュールを提供することにある。 Another object of the present invention is to provide a solar cell encapsulant formed by molding the composition for producing a solar cell encapsulant and a solar cell obtained by encapsulating a solar cell element with the solar cell encapsulant. To provide a module.
　上記目的は、メルトフローレート（ＭＦＲ）の異なる２種のエチレン・α－オレフィン共重合体Ａ及びＢの混合物を含む太陽電池用封止膜の製造方法であって、
　ＭＦＲ（ＪＩＳ　Ｋ７２１０に準拠、温度１９０℃、荷重２．１６ｋｇの条件にて測定。以下同じ。）が２～５ｇ／１０ｍｉｎであるエチレン・α－オレフィン共重合体Ａをそのゲル分率が上がらない範囲で分子同士を連結反応させることにより、溶融状態の８０℃における伸長粘度（歪み速度０．０５／ｓの条件にて、Ｈｅｎｃｋｙ歪みが１．０となったときの粘度。以下同じ。）が５５０～５０００ｋＰａ・ｓであるエチレン・α－オレフィン共重合体Ａ’を得る分子鎖連結工程；
　エチレン・α－オレフィン共重合体Ａ’を、ＭＦＲが２０～５０ｇ／１０ｍｉｎであるエチレン・α－オレフィン共重合体Ｂと混合することにより、８０℃における伸長粘度が１００ｋＰａ・ｓ以上であり且つ８０℃における貯蔵弾性率（ＪＩＳ　Ｋ７２４４に準拠して、歪み量１０％、周波数１Ｈｚの条件にて測定。以下同じ。）が４０ｋＰａ以下である太陽電池用封止材製造用組成物を得る混合工程；及び
　前記太陽電池用封止材製造用組成物をシート状に成形して太陽電池用封止材を得る成形工程；
　を含む太陽電池用封止材の製造方法により達成される。 The above object is a method for producing a sealing film for a solar cell comprising a mixture of two ethylene / α-olefin copolymers A and B having different melt flow rates (MFR),
The gel fraction of the ethylene / α-olefin copolymer A having an MFR (conforming to JIS K7210, measured at a temperature of 190 ° C. and a load of 2.16 kg, the same applies hereinafter) of 2 to 5 g / 10 min does not increase. By allowing the molecules to undergo a ligation reaction within a range, the extensional viscosity at 80 ° C. in a molten state (viscosity when Henky strain becomes 1.0 under the condition of strain rate 0.05 / s, the same applies hereinafter). A molecular chain linking step to obtain an ethylene / α-olefin copolymer A ′ having a viscosity of 550 to 5000 kPa · s;
By mixing the ethylene / α-olefin copolymer A ′ with the ethylene / α-olefin copolymer B having an MFR of 20 to 50 g / 10 min, the elongational viscosity at 80 ° C. is 100 kPa · s or more and 80 A mixing step of obtaining a composition for producing a solar cell encapsulant having a storage elastic modulus at ℃ (measured in accordance with JIS K7244 under the conditions of a strain of 10% and a frequency of 1 Hz; the same shall apply hereinafter); And a molding step of obtaining the solar cell sealing material by molding the composition for manufacturing the solar cell sealing material into a sheet shape;
It is achieved by the manufacturing method of the sealing material for solar cells containing.
　上記所定のＭＦＲを有する２種のエチレン・α－オレフィン共重合体を使用するとともに、ＭＦＲが低い方のエチレン・α－オレフィン共重合体Ａについては分子鎖連結反応を行う。これにより、太陽電池用封止材製造用組成物の弾性を過度に上昇させずに伸長粘度を大幅に上昇させることができるので、太陽電池用封止材製造時のシート切れやダレ等が生じず加工性が良好となり、また製造される太陽電池用封止材の外観も良好なものとなる。 The two ethylene / α-olefin copolymers having the predetermined MFR are used, and the ethylene / α-olefin copolymer A having the lower MFR is subjected to a molecular chain linking reaction. As a result, the elongation viscosity can be significantly increased without excessively increasing the elasticity of the solar cell encapsulant manufacturing composition, resulting in sheet breakage or sagging during the production of the solar cell encapsulant. The processability is improved, and the appearance of the produced solar cell encapsulant is also improved.
　本発明の太陽電池用封止材の製造方法の好ましい態様は以下のとおりである。
　（１）前記分子鎖連結工程は、エチレン・α－オレフィン共重合体Ａに有機過酸化物を添加した後、加熱して該有機過酸化物を分解させることにより行う。
　（２）前記加熱は、エチレン・α－オレフィン共重合体Ａと前記有機過酸化物との混合時の加熱により行う。
　（３）前記分子鎖連結工程は、前記エチレン・α－オレフィン共重合体Ａに電離放射線を照射することにより行う。製造される太陽電池用封止材の透明性も良好となる。
　（４）エチレン・α－オレフィン共重合体Ｂの８０℃における伸長粘度が０．０１～５０ｋＰａ・ｓである。
　（５）エチレン・α－オレフィン共重合体Ａ’のＭＦＲが０．１～３．５ｇ／１０ｍｉｎである。
　（６）前記太陽電池用封止材製造用組成物におけるエチレン・α－オレフィン共重合体Ａ’及びＢの合計量１００質量部を基準として、エチレン・α－オレフィン共重合体Ａ’の含有量が１０～７５質量部であり、エチレン・α－オレフィン共重合体Ｂの含有量が２５～９０質量部である。
　（７）前記成形工程をカレンダー成形により行う。 The preferable aspect of the manufacturing method of the sealing material for solar cells of this invention is as follows.
(1) The molecular chain linking step is performed by adding an organic peroxide to the ethylene / α-olefin copolymer A and then heating to decompose the organic peroxide.
(2) The heating is performed by heating during mixing of the ethylene / α-olefin copolymer A and the organic peroxide.
(3) The molecular chain linking step is performed by irradiating the ethylene / α-olefin copolymer A with ionizing radiation. The transparency of the produced solar cell encapsulant is also good.
(4) The elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer B is 0.01 to 50 kPa · s.
(5) The MFR of the ethylene / α-olefin copolymer A ′ is 0.1 to 3.5 g / 10 min.
(6) Content of ethylene / α-olefin copolymer A ′ based on 100 parts by mass of total amount of ethylene / α-olefin copolymer A ′ and B in the composition for producing a sealing material for solar cell Is 10 to 75 parts by mass, and the content of the ethylene / α-olefin copolymer B is 25 to 90 parts by mass.
(7) The molding step is performed by calendar molding.
　また、上記目的は、溶融状態の８０℃における伸長粘度が５５０～５０００ｋＰａであり且つＭＦＲが０．１～３．５ｇ／１０ｍｉｎであるエチレン・α－オレフィン共重合体Ａ’と、ＭＦＲが２０～５０ｇ／１０ｍｉｎであるエチレン・α－オレフィン共重合体Ｂとの樹脂混合物を含み、８０℃における伸長粘度が１００ｋＰａ・ｓ以上であり且つ８０℃における貯蔵弾性率が４０ｋＰａ以下である太陽電池用封止材製造用組成物によっても達成される。 Further, the above object is to provide an ethylene / α-olefin copolymer A ′ having an elongation viscosity at 80 ° C. in a molten state of 550 to 5000 kPa and an MFR of 0.1 to 3.5 g / 10 min, and an MFR of 20 to A sealing for solar cells comprising a resin mixture with an ethylene / α-olefin copolymer B of 50 g / 10 min, an elongational viscosity at 80 ° C. of 100 kPa · s or more and a storage elastic modulus at 80 ° C. of 40 kPa or less It is also achieved by a composition for manufacturing a material.
　本発明の太陽電池用封止材の好ましい態様は以下のとおりである。
　（１）エチレン・α－オレフィン共重合体Ｂの８０℃における伸長粘度が０．０１～５０ｋＰａ・ｓである。
　（２）エチレン・α－オレフィン共重合体Ａ’及びＢの合計量１００質量部を基準として、前記エチレン・α－オレフィン共重合体Ａ’の含有量が１０～７５質量部であり、エチレン・α－オレフィン共重合体Ｂの含有量が２５～９０質量部である。 The preferable aspect of the sealing material for solar cells of this invention is as follows.
(1) The elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer B is 0.01 to 50 kPa · s.
(2) The content of the ethylene / α-olefin copolymer A ′ is 10 to 75 parts by mass based on 100 parts by mass of the total amount of the ethylene / α-olefin copolymer A ′ and B, The content of α-olefin copolymer B is 25 to 90 parts by mass.
　更に、本発明は、上記太陽電池用封止材製造用組成物がシート状に成形された太陽電池及び表面側保護部材、太陽電池素子及び裏面側保護部材を有する太陽電池モジュールであって、前記太陽電池素子が本発明の太陽電池用封止材により封止されている太陽電池モジュールを提供する。 Furthermore, the present invention is a solar cell module comprising a solar cell and a surface side protective member, a solar cell element and a back side protective member, wherein the composition for producing a solar cell encapsulant is formed into a sheet shape, Provided is a solar cell module in which a solar cell element is sealed with the solar cell sealing material of the present invention.
　本発明に係る太陽電池用封止材製造用組成物は加工性が良好であり、製造される太陽電池用封止材は優れた外観性を有する。したがって、外観性に優れる太陽電池用封止材を安定的且つ効率的に製造することが可能となる。 The composition for producing a solar cell encapsulant according to the present invention has good processability, and the produced solar cell encapsulant has an excellent appearance. Therefore, it is possible to stably and efficiently manufacture a solar cell sealing material having excellent appearance.
一般的な太陽電池モジュールの概略断面図である。It is a schematic sectional drawing of a common solar cell module.
　以下、本発明を詳細に説明する。上述したように、本発明の太陽電池用封止材の製造方法は、ＭＦＲが２～５ｇ／ｍｉｎであるエチレン・α－オレフィン共重合体Ａ（以下、単に「共重合体Ａ」とも称する。）をゲル分率が上がらない範囲で分子同士を連結反応させる分子鎖連結工程、ＭＦＲが２０～５０ｇ／１０ｍｉｎであるエチレン・α－オレフィン共重合体Ｂ（以下、単に「共重合体Ｂ」とも称する。）を分子鎖連結反応後のエチレン・α－オレフィン共重合体Ａ’と混合する混合工程、及び、太陽電池用封止材製造用組成物をシート状に成形する成形工程を含む。 Hereinafter, the present invention will be described in detail. As described above, the method for producing a solar cell encapsulant of the present invention is also referred to as an ethylene / α-olefin copolymer A (hereinafter simply referred to as “copolymer A”) having an MFR of 2 to 5 g / min. ) Is a molecular chain linking step in which molecules are linked to each other within a range where the gel fraction does not increase, an ethylene / α-olefin copolymer B (hereinafter simply referred to as “copolymer B”) having an MFR of 20 to 50 g / 10 min. A mixing step of mixing with the ethylene / α-olefin copolymer A ′ after the molecular chain linking reaction, and a molding step of molding the composition for producing a solar cell encapsulant into a sheet.
　［分子鎖連結工程］
　エチレン・α－オレフィン共重合体Ａの分子鎖連結工程は有機過酸化物又は電離放射線を用いて行うことができる。 [Molecular chain linking step]
The molecular chain linking step of the ethylene / α-olefin copolymer A can be performed using an organic peroxide or ionizing radiation.
　有機過酸化物を用いる分子鎖連結工程は、エチレン・α－オレフィン共重合体Ａに有機過酸化物を添加して、その有機過酸化物を加熱により分解させてラジカルを発生させ、エチレン・α－オレフィン共重合体Ａの分子鎖同士を連結させることにより行う。 In the molecular chain linking step using an organic peroxide, an organic peroxide is added to the ethylene / α-olefin copolymer A, and the organic peroxide is decomposed by heating to generate radicals. -It is carried out by connecting the molecular chains of the olefin copolymer A together.
　有機過酸化物の添加量は、エチレン・α－オレフィン共重合体Ａ１００質量部に対して０．０５～０．１２５質量部が好ましく、０．０８～０．１２質量部が更に好ましい。使用することができる有機過酸化物としては、太陽電池モジュールの製造時のモジュール化時の架橋に使用される後述の有機過酸化物と同様のものと使用することができる。 The amount of the organic peroxide added is preferably 0.05 to 0.125 parts by mass, more preferably 0.08 to 0.12 parts by mass with respect to 100 parts by mass of the ethylene / α-olefin copolymer A. The organic peroxide that can be used can be the same as the organic peroxide described later that is used for cross-linking during modularization when manufacturing the solar cell module.
　分子鎖連結反応は、有機過酸化物をエチレン・α－オレフィン共重合体Ａに添加して混合するときの加熱により行われることが好ましい。この際の加熱温度は有機過酸化物が分解する温度以上であればよいが、例えば１６０～２００℃である。 The molecular chain linking reaction is preferably performed by heating when an organic peroxide is added to the ethylene / α-olefin copolymer A and mixed. The heating temperature at this time may be higher than the temperature at which the organic peroxide is decomposed, but is, for example, 160 to 200 ° C.
　分子鎖連結反応は、電離放射線をエチレン・α－オレフィン共重合体Ａに照射することにより行ってもよい。電離放射線の照射は、共重合体Ａのゲル分率が上昇しない範囲で８０℃伸長粘度が以下に記述する範囲となるように行う。電離放射線としては、電子線、α線、β線、γ線、中性子線等を使用することができ、中でもγ線が好ましい。 The molecular chain linking reaction may be performed by irradiating the ethylene / α-olefin copolymer A with ionizing radiation. Irradiation with ionizing radiation is performed so that the 80 ° C. extensional viscosity is in the range described below within a range where the gel fraction of the copolymer A does not increase. As the ionizing radiation, electron beams, α rays, β rays, γ rays, neutron rays and the like can be used, and among them, γ rays are preferable.
　電離放射線の照射強度は、エチレン・α－オレフィン共重合体Ａの８０℃伸長粘度が下記の範囲になるように設定すればよく、例えば、５～１５ｋＧｙである。照射時のエチレン・α－オレフィン共重合体の形状は特に限定されず、ペレット状等でよい。 The irradiation intensity of the ionizing radiation may be set so that the 80 ° C. extensional viscosity of the ethylene / α-olefin copolymer A falls within the following range, for example, 5 to 15 kGy. The shape of the ethylene / α-olefin copolymer at the time of irradiation is not particularly limited, and may be a pellet or the like.
　電離放射線により分子鎖連結反応を行った場合には、有機過酸化物による場合と比較して、製造される太陽電池用封止材の透明性（光線透過率及びヘイズ）が良好となる。 When the molecular chain linking reaction is performed by ionizing radiation, the transparency (light transmittance and haze) of the solar cell encapsulant to be produced is better than that by the organic peroxide.
　有機過酸化物又は電離放射線による分子鎖連結反応では、エチレン・α－オレフィン共重合体Ａの分子鎖同士が連結するものの、ゲル分率は上昇しない。本発明において、ゲル分率が上昇しないとは、分子鎖連結反応の前及び後のいずれにおいてもゲル分率が０％であることを意味する。また、分子鎖連結反応後であるエチレン・α－オレフィン共重合体Ａ’の８０℃伸長粘度が５５０～５０００ｋＰａ・ｓである。８０℃伸長粘度が５５０ｋＰａ・ｓより小さいとエチレン・α－オレフィン共重合体Ｂと混合したときに太陽電池用封止材製造用組成物の８０℃における伸長粘度が上がらず、加工性が低下する。５０００ｋＰａ・ｓより大きいと混合してもゲル（粒）が必ず発生してしまい、太陽電池用封止材の製品としての外観が低下する。なお、好ましくは５５０～３０００ｋＰａ・ｓ、更に好ましくは８００～２７００ｋＰａ・ｓの範囲となるように分子鎖連結反応を行う。 In the molecular chain linking reaction by organic peroxide or ionizing radiation, although the molecular chains of ethylene / α-olefin copolymer A are linked together, the gel fraction does not increase. In the present invention, the phrase “the gel fraction does not increase” means that the gel fraction is 0% before and after the molecular chain linking reaction. The 80 ° C. extensional viscosity of the ethylene / α-olefin copolymer A ′ after the molecular chain linking reaction is 550 to 5000 kPa · s. When the 80 ° C. extensional viscosity is less than 550 kPa · s, when mixed with the ethylene / α-olefin copolymer B, the elongation viscosity at 80 ° C. of the composition for producing a sealing material for solar cells does not increase, and the workability decreases. . If it is greater than 5000 kPa · s, gels (grains) are always generated even when mixed, and the appearance of the solar cell encapsulant as a product is degraded. The molecular chain linking reaction is preferably carried out so as to be in the range of 550 to 3000 kPa · s, more preferably 800 to 2700 kPa · s.
　分子鎖連結反応が完了した後、反応物を冷却し、適宜ペレット化した後、次の混合工程に付しても良いし、そのまま次の混合工程においてエチレン・α－オレフィン共重合体Ｂと混合してもよい。 After completion of the molecular chain linking reaction, the reaction product is cooled, pelletized as appropriate, and may be subjected to the next mixing step, or may be directly mixed with the ethylene / α-olefin copolymer B in the next mixing step. May be.
　［混合工程］
　混合工程は、分子鎖連結反応を経たエチレン・α－オレフィン共重合体Ａ’をＭＦＲが２０～５０ｇ／１０ｍｉｎであるエチレン・α－オレフィン共重合体Ｂ、及び必要に応じて後述する添加剤と混合する。混合はロールミル等通常の手法により行うことができる。混合時の温度は、エチレン・α－オレフィン共重合体Ａ’及びＢの融点以上であればよく、例えば６０～１００℃である。混合することにより本発明の太陽電池用封止材製造用組成物が得られる。 [Mixing process]
In the mixing step, the ethylene / α-olefin copolymer A ′ having undergone the molecular chain linking reaction is converted into an ethylene / α-olefin copolymer B having an MFR of 20 to 50 g / 10 min, and additives described later as necessary. Mix. Mixing can be performed by a normal method such as a roll mill. The temperature at the time of mixing may be at least the melting point of the ethylene / α-olefin copolymers A ′ and B, and is, for example, 60 to 100 ° C. By mixing, the composition for manufacturing a solar cell sealing material of the present invention is obtained.
　この太陽電池用封止材製造用組成物は、８０℃における伸長粘度（歪み速度０．０５／ｓの条件にて、Ｈｅｎｃｋｙ歪みが１．０となったときの粘度。以下同じ。）が１００ｋＰａ・ｓ以上、好ましくは１００～２０００ｋＰａ・ｓ、より好ましくは１００～１０００ｋＰａ・ｓ、更に好ましくは１００～５００ｋＰａ・ｓであり且つ８０℃における貯蔵弾性率（ＪＩＳ　Ｋ７２４４に準拠して、歪み量１０％、周波数１Ｈｚの条件にて測定。以下同じ。）が４０ｋＰａ以下、好ましくは５～４０ｋＰａ、より好ましくは１０～４０ｋＰａ、更に好ましくは２０～４０ｋＰａである。この範囲とされていることにより、加工性及び外観性に優れたものとなる。 This composition for producing a sealing material for a solar cell has an elongational viscosity at 80 ° C. (viscosity when the Henky strain is 1.0 under the condition of a strain rate of 0.05 / s. The same applies hereinafter). S or more, preferably 100 to 2000 kPa · s, more preferably 100 to 1000 kPa · s, still more preferably 100 to 500 kPa · s, and storage elastic modulus at 80 ° C. (strain amount 10% in accordance with JIS K7244) , Measured at a frequency of 1 Hz. The same shall apply hereinafter)) of 40 kPa or less, preferably 5 to 40 kPa, more preferably 10 to 40 kPa, and even more preferably 20 to 40 kPa. By being in this range, it becomes excellent in workability and appearance.
　エチレン・α－オレフィン共重合体Ａ’及びＢの混合比率は、太陽電池用封止材製造用組成物の８０℃貯蔵弾性率及び８０℃伸長粘度が上記範囲内になればよく、エチレン・α－オレフィン共重合体Ａ’の８０℃伸長粘度に応じて適宜変更することができる。 The mixing ratio of the ethylene / α-olefin copolymers A ′ and B is sufficient if the 80 ° C. storage elastic modulus and 80 ° C. elongation viscosity of the composition for producing a solar cell encapsulant are within the above ranges. -It can be appropriately changed according to the 80 ° C elongation viscosity of the olefin copolymer A '.
　例えば、エチレン・α－オレフィン共重合体Ａ’及びＢの合計質量１００質量部に対して、エチレン・α－オレフィン共重合体Ａ’の含有量が１０～７５質量部であり、エチレン・α－オレフィン共重合体Ｂの含有量が２５～９０質量部であることが好ましい。 For example, the ethylene / α-olefin copolymer A ′ and B have a total mass of 100 parts by mass, and the ethylene / α-olefin copolymer A ′ content is 10 to 75 parts by mass. The content of the olefin copolymer B is preferably 25 to 90 parts by mass.
　特に好ましくは、エチレン・α－オレフィン共重合体Ａ’及びＢの合計質量１００質量部に対して、エチレン・α－オレフィン共重合体Ａ’の含有量が２０～５０質量部であり、エチレン・α－オレフィン共重合体Ｂの含有量が５０～８０質量部であることが好ましい。更に好ましくは、エチレン・α－オレフィン共重合体Ａ’及びＢの合計質量１００質量部に対して、エチレン・α－オレフィン共重合体Ａ’の含有量が２０～４０質量部であり、エチレン・α－オレフィン共重合体Ｂの含有量が６０～８０質量部であることが好ましい。 Particularly preferably, the content of the ethylene / α-olefin copolymer A ′ is 20 to 50 parts by mass with respect to 100 parts by mass of the total mass of the ethylene / α-olefin copolymers A ′ and B, The content of α-olefin copolymer B is preferably 50 to 80 parts by mass. More preferably, the content of the ethylene / α-olefin copolymer A ′ is 20 to 40 parts by mass with respect to 100 parts by mass of the total mass of the ethylene / α-olefin copolymers A ′ and B, The content of α-olefin copolymer B is preferably 60 to 80 parts by mass.
　［成形工程］
　成形工程では、太陽電池用封止材製造用組成物をシート状に成形して太陽電池用封止材を得る。成形方法は特に限定されず、通常の押出成形、又はカレンダー成形（カレンダリング）等により成形してシート状物を得る方法により製造することができる。太陽電池用封止材の厚さは特に制限されないが、０．０５～２ｍｍ、好ましくは０．３～０．８ｍｍ、更に好ましくは０．４～０．７ｍｍである。 [Molding process]
In the molding step, the solar cell encapsulant manufacturing composition is formed into a sheet shape to obtain a solar cell encapsulant. The molding method is not particularly limited, and it can be produced by a method of obtaining a sheet by molding by ordinary extrusion molding, calendar molding (calendering) or the like. The thickness of the solar cell encapsulant is not particularly limited, but is 0.05 to 2 mm, preferably 0.3 to 0.8 mm, and more preferably 0.4 to 0.7 mm.
　以上のようにして本発明の太陽電池用封止材の製造方法が行われる。本発明では、上記所定のＭＦＲを有する２種のエチレン・α－オレフィン共重合体Ａ及びＢを使用するとともに、ＭＦＲが低い方のエチレン・α－オレフィン共重合体Ａについては分子連結反応を行う。これにより、太陽電池用封止材製造用組成物の弾性を過度に上昇させずに伸長粘度を大幅に上昇させることができるので、太陽電池用封止材製造時のシート切れやダレ等が生じず加工性が良好となり、また製造される太陽電池用封止材の外観も良好なものとなる。 As described above, the method for producing the solar cell sealing material of the present invention is performed. In the present invention, the two ethylene / α-olefin copolymers A and B having the predetermined MFR are used, and the ethylene / α-olefin copolymer A having the lower MFR is subjected to a molecular linking reaction. . As a result, the elongation viscosity can be significantly increased without excessively increasing the elasticity of the solar cell encapsulant manufacturing composition, resulting in sheet breakage or sagging during the production of the solar cell encapsulant. The processability is improved, and the appearance of the produced solar cell encapsulant is also improved.
　以下、本発明に使用する材料についてそれぞれ説明する。 Hereinafter, each material used in the present invention will be described.
　［エチレン・α－オレフィン共重合体Ａ及びＢ］
　エチレン・α－オレフィン共重合体Ａ（分子鎖連結反応前）のＭＦＲは、２～５ｇ／１０ｍｉｎである。ＭＦＲが２ｇ／１０ｍｉｎより小さいと流動性が低すぎて、良好に混合されず、外観が悪化する。また、ＭＦＲが５ｇ／１０ｍｉｎより大きいと架橋効果があまり出ない。なお、好ましくは２～４ｇ／１０ｍｉｎである。一方、エチレン・α－オレフィン共重合体ＢのＭＦＲは、２０～５０ｇ／１０ｍｉｎである。ＭＦＲが２０ｇ／１０ｍｉｎより小さいと外観が改善しない。またＭＦＲが５０ｇ／１０ｍｉｎより大きいと混合しにくくなる。なお、好ましくは２５～４０ｇ／１０ｍｉｎ、更に好ましく２７～３５ｇ／１０ｍｉｎである。エチレン・α－オレフィン共重合体Ａ’（分子鎖連結反応後）のＭＦＲは、共重合体Ａよりも低くなり、例えば０．１～３．５ｇ／１０ｍｉｎ、好ましくは０．５～２．５ｇ／１０ｍｉｎである。 [Ethylene / α-olefin copolymers A and B]
The MFR of the ethylene / α-olefin copolymer A (before the molecular chain linking reaction) is 2 to 5 g / 10 min. If the MFR is less than 2 g / 10 min, the fluidity is too low to be mixed well and the appearance deteriorates. On the other hand, if the MFR is larger than 5 g / 10 min, the crosslinking effect is not so much. It is preferably 2 to 4 g / 10 min. On the other hand, the MFR of the ethylene / α-olefin copolymer B is 20 to 50 g / 10 min. When the MFR is less than 20 g / 10 min, the appearance is not improved. Moreover, when MFR is larger than 50 g / 10 min, it becomes difficult to mix. It is preferably 25 to 40 g / 10 min, more preferably 27 to 35 g / 10 min. The MFR of the ethylene / α-olefin copolymer A ′ (after the molecular chain linking reaction) is lower than that of the copolymer A, for example, 0.1 to 3.5 g / 10 min, preferably 0.5 to 2.5 g. / 10 min.
　本発明において、エチレン・α－オレフィン共重合体Ａ及びＡ’並びにＢの密度の差は、０．０１ｇ／ｃｍ３未満であることが好ましい。また、エチレン・α－オレフィン共重合体Ａ及びＡ’並びにＢの融点の差が１０℃未満であることが好ましい。これにより、外観性及び加工性に更に優れる太陽電池用封止膜製造用組成物を得ることができる。 In the present invention, the difference in density between the ethylene / α-olefin copolymers A and A ′ and B is preferably less than 0.01 g / cm 3 . Further, the difference in melting point between the ethylene / α-olefin copolymers A and A ′ and B is preferably less than 10 ° C. Thereby, the composition for solar cell sealing film manufacture which is further excellent in external appearance property and workability can be obtained.
　具体的には、エチレン・α－オレフィン共重合体Ａ及びＡ’並びにＢの密度は０．８６～０．９０ｇ／ｃｍ３であることが好ましく、０．８７５～０．８８５ｇ／ｃｍ３であることが特に好ましい。本発明において、エチレン－α－オレフィンＡ及びＢの密度は、ＪＩＳ　Ｋ　７１１２に従って求めた値のことをいう。 Specifically, the density of the ethylene / α-olefin copolymers A and A ′ and B is preferably 0.86 to 0.90 g / cm 3 , and 0.875 to 0.885 g / cm 3 . It is particularly preferred. In the present invention, the density of ethylene-α-olefins A and B is a value determined according to JIS K 7112.
　また、エチレン・α－オレフィン共重合体Ａ及びＡ’並びにＢの融点は５０～８０℃であることが好ましく、５０～７０℃であることが更に好ましい。本発明においてエチレン・α－オレフィン共重合体Ａ及びＢの融点は、ＪＩＳ　Ｋ　７１２１に従い、熱流束示差走査熱量測定で得られたＤＳＣ曲線における融解ピーク温度のことをいう。 In addition, the melting points of the ethylene / α-olefin copolymers A and A ′ and B are preferably 50 to 80 ° C., and more preferably 50 to 70 ° C. In the present invention, the melting points of the ethylene / α-olefin copolymers A and B are melting peak temperatures in a DSC curve obtained by heat flux differential scanning calorimetry according to JIS K7121.
　本発明において、分子鎖連結反応前であるエチレン・α－オレフィン共重合体Ａの溶融状態の８０℃における伸長粘度は、一般に５０～２００ｋＰａ・ｓである。そして、分子鎖連結反応後であるエチレン・α－オレフィン共重合体Ａ’の溶融状態の８０℃における伸長粘度は、上述したとおり、５５０～５０００ｋＰａ・ｓである。共重合体Ａ’の８０℃における伸長粘度は、共重合体Ａのそれよりも２．５～１００倍あることが好ましい。共重合体Ｂの８０℃における身長粘度は０．０１～５０ｋＰａ・ｓであることが好ましく、０．０１～１０ｋＰａであることが更に好ましい。 In the present invention, the elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer A in the molten state before the molecular chain linking reaction is generally 50 to 200 kPa · s. The elongation viscosity at 80 ° C. in the molten state of the ethylene / α-olefin copolymer A ′ after the molecular chain linking reaction is 550 to 5000 kPa · s as described above. The elongation viscosity at 80 ° C. of the copolymer A ′ is preferably 2.5 to 100 times that of the copolymer A. The height viscosity of copolymer B at 80 ° C. is preferably 0.01 to 50 kPa · s, more preferably 0.01 to 10 kPa.
　また、エチレン・α－オレフィン共重合体Ａ’とＢの屈折率の差が０．００１以下であることが太陽電池用封止材の透明性が向上する点で好ましい。 Further, the difference in refractive index between the ethylene / α-olefin copolymer A ′ and B is preferably 0.001 or less from the viewpoint of improving the transparency of the solar cell encapsulant.
　エチレン・α－オレフィン共重合体Ａ及びＢは、エチレン由来の構成単位を主成分とし、更に炭素数３～１２のα－オレフィン、例えば、プロピレン、１－ブテン、１-へキセン、１－オクテン、４－メチルペンテン－１、４－メチル－へキセン－１、４，４－ジメチル－ペンテン－１等由来の１種又は複数種の構成単位を有するエチレン・α－オレフィン共重合体（ターポリマー等も含む）である。エチレン・α－オレフィン共重合体の具体例としては、エチレン・１－ブテン共重合体、エチレン・１－オクテン共重合体、エチレン・４－メチル－ペンテン－１共重合体、エチレン・ブテン・ヘキセンターポリマー、エチレン・プロピレン・オクテンターポリマー、エチレン・ブテン・オクテンターポリマー等が挙げられる。エチレン・α－オレフィン共重合体におけるα－オレフィンの含有量は、５～４０質量％が好ましく、１０～３５質量％がより好ましく、１５～３０質量％が更に好ましい。α－オレフィンの含有量が少ないと太陽電池用封止材の柔軟性や耐衝撃性が十分でない場合があり、多過ぎると耐熱性が低い場合がある。 The ethylene / α-olefin copolymers A and B are composed mainly of structural units derived from ethylene and further have an α-olefin having 3 to 12 carbon atoms, such as propylene, 1-butene, 1-hexene, and 1-octene. , Ethylene-α-olefin copolymer having one or more structural units derived from 4-methylpentene-1, 4-methyl-hexene-1, 4,4-dimethyl-pentene-1, etc. (terpolymer) Etc.). Specific examples of the ethylene / α-olefin copolymer include an ethylene / 1-butene copolymer, an ethylene / 1-octene copolymer, an ethylene-4-methyl-pentene-1 copolymer, an ethylene / butene / hexene copolymer. Center polymers, ethylene / propylene / octene terpolymers, ethylene / butene / octene terpolymers, and the like. The content of α-olefin in the ethylene / α-olefin copolymer is preferably 5 to 40% by mass, more preferably 10 to 35% by mass, and still more preferably 15 to 30% by mass. If the α-olefin content is small, the solar cell encapsulant may not have sufficient flexibility and impact resistance, and if it is too much, the heat resistance may be low.
　本発明において、エチレン・α－オレフィン共重合体Ａ及びＢは、チーグラーナッタ触媒やメタロセン触媒を用いて重合されたものを使用することができ、特に直鎖状のエチレン・α－オレフィン共重合体を好ましく使用することができる。本発明では、メタロセン触媒により重合されたエチレン・α－オレフィン共重合体（以下、ｍ－ＬＬＤＰＥとも称する。）を使用することが特に好ましい。ｍ－ＬＬＤＰＥはシャープな分子量分布を有することから加工性の点で更に優れている。分子量分布Ｍｗ／Ｍｎは２．０～３．５であることが好ましい。エチレン・α－オレフィン共重合体Ａ及びＢは、ランダム共重合体でもブロック共重合体でもよく、ランダム共重合体が好ましい。エチレン・α－オレフィン共重合体Ａ及びＢは結晶性でも非晶性でもよく、非晶性が好ましい。 In the present invention, the ethylene / α-olefin copolymers A and B may be those polymerized using a Ziegler-Natta catalyst or a metallocene catalyst, and in particular, linear ethylene / α-olefin copolymers. Can be preferably used. In the present invention, it is particularly preferable to use an ethylene / α-olefin copolymer (hereinafter also referred to as m-LLDPE) polymerized with a metallocene catalyst. Since m-LLDPE has a sharp molecular weight distribution, it is further excellent in terms of workability. The molecular weight distribution Mw / Mn is preferably 2.0 to 3.5. The ethylene / α-olefin copolymers A and B may be random copolymers or block copolymers, and are preferably random copolymers. The ethylene / α-olefin copolymers A and B may be crystalline or amorphous, and preferably amorphous.
　［架橋剤］
　本発明の太陽電池用封止材製造用組成物には、架橋剤を含有させ、エチレン・α－オレフィン共重合体Ａ及びＢの架橋構造を形成することが好ましい。架橋剤は、有機過酸化物又は光重合開始剤を用いることが好ましい。なかでも、接着力、耐湿性、耐貫通性の温度依存性が改善された封止材が得られることから、有機過酸化物を用いるのが好ましい。 [Crosslinking agent]
The composition for producing a sealing material for solar cells of the present invention preferably contains a crosslinking agent to form a crosslinked structure of the ethylene / α-olefin copolymers A and B. As the crosslinking agent, an organic peroxide or a photopolymerization initiator is preferably used. Among them, it is preferable to use an organic peroxide because a sealing material with improved temperature dependency of adhesive strength, moisture resistance, and penetration resistance can be obtained.
　有機過酸化物としては、１００℃以上の温度で分解してラジカルを発生するものであれば、どのようなものでも使用することができる。有機過酸化物は、一般に、成膜温度、組成物の調整条件、硬化温度、被着体の耐熱性、貯蔵安定性を考慮して選択される。特に、半減期１０時間の分解温度が７０℃以上のものが好ましい。 Any organic peroxide may be used as long as it decomposes at a temperature of 100 ° C. or higher to generate radicals. The organic peroxide is generally selected in consideration of the film formation temperature, the adjustment conditions of the composition, the curing temperature, the heat resistance of the adherend, and the storage stability. In particular, the one having a decomposition temperature of 70 ° C. or more with a half-life of 10 hours is preferable.
　前記有機過酸化物としては、樹脂の加工温度・貯蔵安定性の観点から例えば、ベンゾイルパーオキサイド系硬化剤、ｔｅｒｔ－ヘキシルパーオキシピバレート、ｔｅｒｔ－ブチルパーオキシピバレート、３，５，５－トリメチルヘキサノイルパーオキサイド、ジ－ｎ－オクタノイルパーオキサイド、ラウロイルパーオキサイド、ステアロイルパーオキサイド、１，１，３，３－テトラメチルブチルパーオキシ－２－エチルヘキサノエート、スクシニックアシドパーオキサイド、２，５－ジメチル－２，５－ジ（ｔｅｒｔ－ブチルパーオキシ）ヘキサン、２，５－ジメチル－２，５－ジ（２－エチルヘキサノイルパーオキシ）ヘキサン、１－シクロヘキシル－１－メチルエチルパーオキシ－２－エチルヘキサノエート、ｔｅｒｔ－ヘキシルパーオキシ－２－エチルヘキサノエート、４－メチルベンゾイルパーオキサイド、ｔｅｒｔ－ブチルパーオキシ－２－エチルヘキサノエート、ｍ－トルオイル＋ベンゾイルパーオキサイド、ベンゾイルパーオキサイド、１，１－ビス（ｔｅｒｔ－ブチルパーオキシ）－２－メチルシクロヘキサネート、１，１－ビス（ｔｅｒｔ－ヘキシルパーオキシ）－３，３，５－トリメチルシクロヘキサネート、１，１－ビス（ｔｅｒｔ－ヘキシルパーオキシ）シクロヘキサネート、１，１－ビス（ｔｅｒｔ－ブチルパーオキシ）－３，３，５－トリメチルシクロヘキサン、１，１－ビス（ｔｅｒｔ－ブチルパーオキシ）シクロヘキサン、１，１－ビス（ｔｅｒｔ－ヘキシルパーオキシ）－３，３，５－トリメチルシクロヘキサン、２，２－ビス（４，４－ジ－ｔｅｒｔ－ブチルパーオキシシクロヘキシル）プロパン、１，１－ビス（ｔｅｒｔ－ブチルパーオキシ）シクロドデカン、ｔｅｒｔ－ヘキシルパーオキシイソプロピルモノカーボネート、ｔｅｒｔ－ブチルパーオキシマレイックアシド、ｔｅｒｔ－ブチルパーオキシ－３，３，５－トリメチルヘキサン、ｔｅｒｔ－ブチルパーオキシラウレート、２，５－ジメチル－２，５－ジ（メチルベンゾイルパーオキシ）ヘキサン、ｔｅｒｔ－ブチルパーオキシイソプロピルモノカーボネート、ｔｅｒｔ－ブチルパーオキシ－２－エチルヘキシルモノカーボネート、ｔｅｒｔ－ヘキシルパーオキシベンゾエート、２，５－ジ－メチル－２，５－ジ（ベンゾイルパーオキシ）ヘキサン、等が挙げられる。 Examples of the organic peroxide include, from the viewpoint of processing temperature and storage stability of the resin, for example, benzoyl peroxide curing agent, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, 3, 5, 5- Trimethylhexanoyl peroxide, di-n-octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, succinic acid peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethyl Peroxy-2-ethylhexanoate, tert-hexylpa Oxy-2-ethylhexanoate, 4-methylbenzoyl peroxide, tert-butylperoxy-2-ethylhexanoate, m-toluoyl + benzoyl peroxide, benzoyl peroxide, 1,1-bis (tert-butyl Peroxy) -2-methylcyclohexanate, 1,1-bis (tert-hexylperoxy) -3,3,5-trimethylcyclohexanate, 1,1-bis (tert-hexylperoxy) cyclohexanate 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, 1,1-bis (tert-hexylperoxy)- 3,3,5-trimethylcyclohexane, 2,2-bis (4,4- -Tert-butylperoxycyclohexyl) propane, 1,1-bis (tert-butylperoxy) cyclododecane, tert-hexylperoxyisopropyl monocarbonate, tert-butylperoxymaleic acid, tert-butylperoxy-3 , 3,5-trimethylhexane, tert-butylperoxylaurate, 2,5-dimethyl-2,5-di (methylbenzoylperoxy) hexane, tert-butylperoxyisopropylmonocarbonate, tert-butylperoxy- Examples include 2-ethylhexyl monocarbonate, tert-hexyl peroxybenzoate, 2,5-di-methyl-2,5-di (benzoylperoxy) hexane, and the like.
　ベンゾイルパーオキサイド系硬化剤としては、７０℃以上の温度で分解してラジカルを発生するものであればいずれも使用可能であるが、半減期１０時間の分解温度が５０℃以上のものが好ましく、調製条件、成膜温度、硬化（貼り合わせ）温度、被着体の耐熱性、貯蔵安定性を考慮して適宜選択できる。使用可能なベンゾイルパーオキサイド系硬化剤としては、例えば、ベンゾイルパーオキサイド、２，５－ジメチルヘキシル－２，５－ビスパーオキシベンゾエート、ｐ－クロロベンゾイルパーオキサイド、ｍ－トルオイルパーオキサイド、２，４－ジクロロベンゾイルパーオキサイド、ｔ－ブチルパーオキシベンゾエート等が挙げられる。ベンゾイルパーオキサイド系硬化剤は１種でも２種以上を組み合わせて使用してもよい。 As the benzoyl peroxide-based curing agent, any can be used as long as it decomposes at a temperature of 70 ° C. or higher to generate radicals, and those having a decomposition temperature of 50 hours or higher with a half-life of 10 hours are preferable, It can be appropriately selected in consideration of preparation conditions, film formation temperature, curing (bonding) temperature, heat resistance of the adherend, and storage stability. Usable benzoyl peroxide curing agents include, for example, benzoyl peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, p-chlorobenzoyl peroxide, m-toluoyl peroxide, 2, Examples include 4-dichlorobenzoyl peroxide and t-butyl peroxybenzoate. The benzoyl peroxide curing agent may be used alone or in combination of two or more.
　有機過酸化物として、特に、２，５－ジメチル－２，５－ジ（ｔｅｒｔ－ブチルパーオキシ）ヘキサン、又はｔｅｒｔ－ブチルパーオキシ－２－エチルヘキシルモノカーボネートが好ましい。これにより、良好に架橋され、優れた透明性を有する太陽電池用封止材が得られる。 As the organic peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane or tert-butylperoxy-2-ethylhexyl monocarbonate is particularly preferable. Thereby, the sealing material for solar cells which is bridge | crosslinked favorably and has the outstanding transparency is obtained.
　太陽電池用封止材製造用組成物に使用する有機過酸化物の含有量は、エチレン・α－オレフィン共重合体Ａ及びＢの合計量１００質量部に対して、好ましくは０．１～５質量部、より好ましくは０．２～３質量部であることが好ましい。有機過酸化物の含有量は、少ないと架橋硬化時において架橋速度が低下する場合があり、多くなると共重合体との相溶性が悪くなる恐れがある。 The content of the organic peroxide used in the composition for producing a sealing material for solar cells is preferably 0.1 to 5 with respect to 100 parts by mass of the total amount of the ethylene / α-olefin copolymers A and B. It is preferable that the amount is part by mass, more preferably 0.2 to 3 parts by mass. If the content of the organic peroxide is small, the crosslinking speed may be lowered during the crosslinking and curing, and if the content is large, the compatibility with the copolymer may be deteriorated.
　また、光重合開始剤としては、公知のどのような光重合開始剤でも使用することができるが、配合後の貯蔵安定性の良いものが望ましい。このような光重合開始剤としては、例えば、２－ヒドロキシ－２－メチル－１－フェニルプロパン－１－オン、１－ヒドロキシシクロヘキシルフェニルケトン、２－メチル－１－（４－（メチルチオ）フェニル）－２－モルホリノプロパン－１などのアセトフェノン系、ベンジルジメチルケタ－ルなどのベンゾイン系、ベンゾフェノン、４－フェニルベンゾフェノン、ヒドロキシベンゾフェノンなどのベンゾフェノン系、イソプロピルチオキサントン、２－４－ジエチルチオキサントンなどのチオキサントン系、その他特殊なものとしては、メチルフェニルグリオキシレ－トなどが使用できる。特に好ましくは、２－ヒドロキシ－２－メチル－１－フェニルプロパン－１－オン、１－ヒドロキシシクロヘキシルフェニルケトン、２－メチル－１－（４－（メチルチオ）フェニル）－２－モルホリノプロパン－１、ベンゾフェノン等が挙げられる。これら光重合開始剤は、必要に応じて、４－ジメチルアミノ安息香酸のごとき安息香酸系又は、第３級アミン系などの公知慣用の光重合促進剤の１種または２種以上を任意の割合で混合して使用することができる。また、光重合開始剤のみの１種単独または２種以上の混合で使用することができる。 As the photopolymerization initiator, any known photopolymerization initiator can be used, but a photopolymerization initiator having good storage stability after blending is desirable. Examples of such photopolymerization initiators include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, and 2-methyl-1- (4- (methylthio) phenyl). Acetophenones such as -2-morpholinopropane-1, benzoins such as benzyldimethylketal, benzophenones such as benzophenone, 4-phenylbenzophenone and hydroxybenzophenone, thioxanthones such as isopropylthioxanthone and 2-4-diethylthioxanthone, As other special ones, methylphenylglyoxylate can be used. Particularly preferably, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1, Examples include benzophenone. These photopolymerization initiators may contain one or more known photopolymerization accelerators such as benzoic acid-based or tertiary amine-based compounds such as 4-dimethylaminobenzoic acid, if necessary. Can be mixed and used. Moreover, it can be used individually by 1 type of only a photoinitiator, or 2 or more types of mixture.
　前記光重合開始剤の含有量は、エチレン・α－オレフィン共重合体Ａ及びＢの合計量１００質量部に対して０．１～５質量部、好ましくは０．２～３質量部である。 The content of the photopolymerization initiator is 0.1 to 5 parts by mass, preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the total amount of the ethylene / α-olefin copolymers A and B.
　［架橋助剤］
　本発明の太陽電池用封止材製造用組成物は、さらに架橋助剤を含んでいることが好ましい。架橋助剤は、エチレン・α－オレフィン共重合体Ａ及びＢのゲル分率を向上させ、太陽電池用封止材の接着性、耐候性を向上させることができる。 [Crosslinking aid]
It is preferable that the composition for manufacturing a sealing material for solar cells of the present invention further contains a crosslinking aid. The crosslinking aid can improve the gel fraction of the ethylene / α-olefin copolymers A and B and improve the adhesion and weather resistance of the solar cell encapsulant.
　架橋助剤の含有量は、エチレン・α－オレフィン共重合体Ａ及びＢの合計量１００質量部に対して、通常０．１～５質量部、好ましくは０．１～３質量部、特に好ましくは０．５～２．５質量部で使用される。これにより、更に架橋後の硬度が向上した封止材が得られる。 The content of the crosslinking aid is usually 0.1 to 5 parts by mass, preferably 0.1 to 3 parts by mass, particularly preferably 100 parts by mass of the total amount of the ethylene / α-olefin copolymers A and B. Is used at 0.5 to 2.5 parts by mass. Thereby, the sealing material which the hardness after bridge | crosslinking improved further is obtained.
　前記架橋助剤（官能基としてラジカル重合性基を有する化合物）としては、トリアリルシアヌレート、トリアリルイソシアヌレート等の３官能の架橋助剤の他、（メタ）アクリルエステル（例、ＮＫエステル等）の単官能又は２官能の架橋助剤等を挙げることができる。なかでも、トリアリルシアヌレートおよびトリアリルイソシアヌレートが好ましく、特にトリアリルイソシアヌレートが好ましい。 Examples of the crosslinking aid (compound having a radical polymerizable group as a functional group) include trifunctional crosslinking aids such as triallyl cyanurate and triallyl isocyanurate, and (meth) acrylic esters (eg, NK ester) ) Monofunctional or bifunctional crosslinking aids. Of these, triallyl cyanurate and triallyl isocyanurate are preferable, and triallyl isocyanurate is particularly preferable.
　［接着性向上剤］
　本発明の太陽電池用封止材製造用組成物においては、更に、接着向上剤を含んでいても良い。接着向上剤としては、シランカップリング剤を用いることができる。これにより、更に優れた接着力を有する太陽電池用封止材とすることができる。前記シランカップリング剤としては、γ－クロロプロピルトリメトキシシラン、ビニルトリエトキシシラン、ビニルトリス（β－メトキシエトキシ）シラン、γ－メタクリロキシプロピルトリメトキシシラン、ビニルトリアセトキシシラン、γ－グリシドキシプロピルトリメトキシシラン、γ－グリシドキシプロピルトリエトキシシラン、β－（３，４－エポキシシクロヘキシル）エチルトリメトキシシラン、ビニルトリクロロシラン、γ－メルカプトプロピルトリメトキシシラン、γ－アミノプロピルトリエトキシシラン、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を挙げることができる。これらシランカップリング剤は、単独で使用しても、又は２種以上組み合わせて使用しても良い。なかでも、γ－メタクリロキシプロピルトリメトキシシランが特に好ましく挙げられる。 [Adhesion improver]
The composition for producing a sealing material for solar cell of the present invention may further contain an adhesion improver. As the adhesion improver, a silane coupling agent can be used. Thereby, it can be set as the sealing material for solar cells which has the further outstanding adhesive force. Examples of the silane coupling agent include γ-chloropropyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, and γ-glycidoxypropyl. Trimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N Mention may be made of -β- (aminoethyl) -γ-aminopropyltrimethoxysilane. These silane coupling agents may be used alone or in combination of two or more. Of these, γ-methacryloxypropyltrimethoxysilane is particularly preferred.
　本発明の太陽電池用封止材製造用組成物におけるシランカップリング剤の含有量は、エチレン・α－オレフィン共重合体Ａ及びＢの合計量１００質量部に対して５質量部以下、好ましくは０．１～２質量部であることが好ましい。 The content of the silane coupling agent in the composition for producing a solar cell sealing material of the present invention is 5 parts by mass or less, preferably 100 parts by mass of the total amount of ethylene / α-olefin copolymers A and B, preferably The amount is preferably 0.1 to 2 parts by mass.
　［その他］
　本発明の太陽電池用封止材製造用組成物は、膜の種々の物性（機械的強度、透明性等の光学的特性、耐熱性、耐光性、架橋速度等）の改良あるいは調整、特に機械的強度の改良のため、必要に応じて、可塑剤、アクリロキシ基含有化合物、メタクリロキシ基含有化合物及び／又はエポキシ基含有化合物などの各種添加剤をさらに含んでいてもよい。 [Others]
The composition for producing a sealing material for solar cells of the present invention improves or adjusts various physical properties of a film (optical properties such as mechanical strength and transparency, heat resistance, light resistance, crosslinking speed, etc.), especially a machine. Various additives such as a plasticizer, an acryloxy group-containing compound, a methacryloxy group-containing compound, and / or an epoxy group-containing compound may be further included as necessary for improving the mechanical strength.
　［太陽電池モジュール］
　本発明の太陽電池モジュールの構造は、本発明の太陽電池用封止材を用いて太陽電池素子を封止することにより製造された構造を含んでいれば特に制限されない。例えば、表面側透明保護部材と裏面側保護部材との間に、本発明の太陽電池用封止材を介在させて架橋一体化させることにより太陽電池素子（単結晶又は多結晶シリコンセル等）を封止させた構造などが挙げられる。 [Solar cell module]
The structure of the solar cell module of the present invention is not particularly limited as long as it includes a structure manufactured by sealing a solar cell element using the solar cell sealing material of the present invention. For example, a solar cell element (single crystal or polycrystalline silicon cell or the like) is formed by crosslinking and integrating the solar cell sealing material of the present invention between the front surface side transparent protective member and the back surface side protective member. Examples include a sealed structure.
　なお、本発明において、太陽電池素子の光が照射される側（表面側）を「表面側」と称し、太陽電池素子の受光面とは反対面側を「裏面側」と称する。 In the present invention, the side of the solar cell element irradiated with light (front side) is referred to as “front side”, and the side opposite to the light receiving surface of the solar cell element is referred to as “back side”.
　太陽電池モジュールにおいて、太陽電池素子を十分に封止するには、例えば、図１に示すように表面側透明保護部材１１、表面側封止材１３Ａ、太陽電池素子１４、裏面側封止材１３Ｂ及び裏面側保護部材１２を積層し、加熱加圧など常法に従って、封止材を架橋硬化させればよい。 In the solar cell module, in order to sufficiently seal the solar cell element, for example, as shown in FIG. 1, the front surface side transparent protective member 11, the front surface side sealing material 13A, the solar cell element 14, the back surface side sealing material 13B. And the back surface side protection member 12 is laminated | stacked, and a sealing material should just be bridge | crosslinked and hardened | cured according to conventional methods, such as heat-pressing.
　加熱加圧するには、例えば、各部材を積層した積層体を、真空ラミネータで温度１３５～１８０℃、さらに１４０～１８０℃、脱気時間０．１～５分、プレス圧力０．１～１．５ｋｇ／ｃｍ2、プレス時間５～１５分で加熱圧着すればよい。 In order to heat and pressurize, for example, a laminated body in which each member is laminated is heated by a vacuum laminator at a temperature of 135 to 180 ° C., further 140 to 180 ° C., a degassing time of 0.1 to 5 minutes, and a press pressure of 0.1 to 1. Heat pressing may be performed at 5 kg / cm 2 and a press time of 5 to 15 minutes.
　この加熱加圧時に、表面側封止材１３Ａおよび裏面側封止材１３Ｂに含まれるエチレン・α－オレフィン共重合体Ａ、Ｂを架橋させることにより、表面側封止材１３Ａおよび裏面側封止材１３Ｂを介して、表面側透明保護部材１１、裏面側透明部材１２、および太陽電池素子１４を一体化させて、太陽電池素子１４を封止することができる。太陽電池素子１４は接続タブ１５で互いに電気的に接続される。 By crosslinking the ethylene / α-olefin copolymers A and B contained in the front surface side sealing material 13A and the back surface side sealing material 13B during the heating and pressurization, the front surface side sealing material 13A and the back surface side sealing material are sealed. The solar cell element 14 can be sealed by integrating the front surface side transparent protective member 11, the back surface side transparent member 12, and the solar cell element 14 via the material 13B. The solar cell elements 14 are electrically connected to each other by connection tabs 15.
　なお、本発明の太陽電池用封止材は、図１に示したような単結晶又は多結晶のシリコン結晶系の太陽電池セルを用いた太陽電池モジュールだけでなく、薄膜シリコン系、薄膜アモルファスシリコン系太陽電池、セレン化銅インジウム（ＣＩＳ）系太陽電池等の薄膜太陽電池モジュールの封止材にも使用することもできる。この場合は、例えば、ガラス基板、ポリイミド基板、フッ素樹脂系透明基板等の表面側透明保護部材の表面上に化学気相蒸着法等により形成された薄膜太陽電池素子層上に、本発明の太陽電池用封止材、裏面側保護部材を積層し、接着一体化させた構造、裏面側保護部材の表面上に形成された太陽電池素子上に、本発明の太陽電池用封止材、表面側透明保護部材を積層し、接着一体化させた構造、又は表面側透明保護部材、表面側封止材、薄膜太陽電池素子、裏面側封止材、及び裏面側保護部材をこの順で積層し、接着一体化させた構造等が挙げられる。なお、本発明において、太陽電池セルや薄膜太陽電池素子を総称して太陽電池素子という。 The solar cell encapsulant of the present invention is not limited to a solar cell module using a single crystal or polycrystalline silicon crystal solar cell as shown in FIG. It can also be used as a sealing material for thin film solar cell modules such as solar cells and copper indium selenide (CIS) solar cells. In this case, for example, the solar cell of the present invention is formed on a thin film solar cell element layer formed by a chemical vapor deposition method or the like on the surface of a surface side transparent protective member such as a glass substrate, a polyimide substrate, or a fluororesin transparent substrate. On the solar cell element formed on the surface of the back surface side protective member, a structure in which the battery sealing material and the back surface side protective member are laminated and bonded and integrated, on the surface side Laminated transparent protective member, bonded and integrated structure, or front side transparent protective member, front side sealing material, thin film solar cell element, back side sealing material, and back side protective member are laminated in this order, For example, a structure that is bonded and integrated. In addition, in this invention, a photovoltaic cell and a thin film solar cell element are named generically, and are called a solar cell element.
　表面側透明保護部材１１は、通常珪酸塩ガラスなどのガラス基板であるのがよい。ガラス基板の厚さは、０．１～１０ｍｍが一般的であり、０．３～５ｍｍが好ましい。ガラス基板は、一般に、化学的に、或いは熱的に強化させたものであってもよい。 The surface side transparent protective member 11 is usually a glass substrate such as silicate glass. The thickness of the glass substrate is generally from 0.1 to 10 mm, and preferably from 0.3 to 5 mm. The glass substrate may generally be chemically or thermally strengthened.
　裏面側保護部材１２は、ポリエチレンテレフタレート（ＰＥＴ）やポリアミドなどのプラスチックフィルムが好ましく用いられる。また、耐熱性、耐湿熱性を考慮してフッ化ポリエチレンフィルム、特にフッ化ポリエチレンフィルム／Ａｌ／フッ化ポリエチレンフィルムをこの順で積層させたフィルムでも良い。また、ガラス板でもよい。 The back side protective member 12 is preferably a plastic film such as polyethylene terephthalate (PET) or polyamide. Further, a film obtained by laminating a fluorinated polyethylene film, particularly a fluorinated polyethylene film / Al / fluorinated polyethylene film in this order in consideration of heat resistance and wet heat resistance may be used. Further, a glass plate may be used.
　なお、本発明の太陽電池用封止材は、太陽電池モジュール（薄膜太陽電池モジュールを含む）の表面側及び／又は裏面側に用いられる封止材に特徴を有する。したがって、表面側透明保護部材、裏面側保護部材、および太陽電池素子などの封止材以外の部材については、従来公知の太陽電池モジュールと同様の構成を有していればよく、特に制限されない。 In addition, the sealing material for solar cells of this invention has the characteristics in the sealing material used for the surface side and / or back surface side of a solar cell module (a thin film solar cell module is included). Therefore, members other than the sealing material such as the front surface side transparent protective member, the back surface side protective member, and the solar cell element may have the same configuration as that of a conventionally known solar cell module, and are not particularly limited.
　以下、本発明を実施例により詳細に説明する。 Hereinafter, the present invention will be described in detail with reference to examples.
［１］分子鎖連結ポリマーの調製（分子鎖連結工程）
　（１）有機過酸化物による調製
　（１－１）分子鎖連結ポリマー１～３
　エチレン・α－オレフィン共重合体Ａ（メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体、ＭＦＲ：３．５ｇ／１０ｍｉｎ、融点：６０℃、密度：０．８８０ｇ／ｃｍ３（カーネルＫＳ３４１Ｔ、日本ポリエチレン社製）、ランダム共重合体、非晶性）に有機過酸化物として２，５－ジメチル－２，５－ジ（ｔ－ブチルパーオキシ）ヘキサンを下記の量で配合し、１８０℃に加熱しながら混合した。この加熱時にエチレン・α－オレフィン共重合体Ａを分子鎖連結反応させた。これにより、分子鎖連結ポリマー（エチレン・α－オレフィン共重合体Ａ’）１～３を得た。添加した有機過酸化物の含有量は以下のとおりである。
　・分子鎖連結ポリマー１：共重合体Ａ１００質量部に対して０．１００質量部
　・分子鎖連結ポリマー２：共重合体Ａ１００質量部に対して０．１２５質量部
　・分子鎖連結ポリマー３：共重合体Ａ１００質量部に対して０．１５０質量部 [1] Preparation of molecular chain linking polymer (molecular chain linking step)
(1) Preparation with organic peroxide (1-1) Molecular chain-linked polymer 1 to 3
Ethylene / α-olefin copolymer A (linear ethylene / α-olefin copolymer polymerized using metallocene catalyst, MFR: 3.5 g / 10 min, melting point: 60 ° C., density: 0.880 g / cm 3 (Kernel KS341T, manufactured by Nippon Polyethylene Co., Ltd.), random copolymer, amorphous) and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane as an organic peroxide in the following amounts It mix | blended and mixed, heating at 180 degreeC. During this heating, the ethylene / α-olefin copolymer A was subjected to molecular chain linking reaction. As a result, molecular chain linked polymers (ethylene / α-olefin copolymer A ′) 1 to 3 were obtained. The content of the added organic peroxide is as follows.
-Molecular chain linked polymer 1: 0.100 parts by mass with respect to 100 parts by mass of copolymer A-Molecular chain linked polymer 2: 0.125 parts by mass with respect to 100 parts by mass of copolymer A-Molecular chain linked polymer 3: co-polymer 0.150 parts by mass with respect to 100 parts by mass of polymer A
　分子鎖連結反応を行う前のエチレン・α－オレフィン共重合体Ａの８０℃での伸長粘度は１１０ｋＰａ・ｓであった。分子鎖連結ポリマー１～３の８０℃での伸長粘度はそれぞれ、１５００ｋＰａ・ｓ、２２００ｋＰａ・ｓ、３０００ｋＰａ・ｓであった。また、分子鎖連結ポリマー１～３のＭＦＲはそれぞれ１ｇ／１０ｍｉｎ、０．７ｇ／１０ｍｉｎ、０．５ｇ／１０ｍｉｎであった。 The elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer A before the molecular chain linking reaction was 110 kPa · s. The elongational viscosities of the molecular chain linked polymers 1 to 3 at 80 ° C. were 1500 kPa · s, 2200 kPa · s, and 3000 kPa · s, respectively. The MFRs of the molecular chain linked polymers 1 to 3 were 1 g / 10 min, 0.7 g / 10 min, and 0.5 g / 10 min, respectively.
　（１－２）分子鎖連結ポリマー７
　上記エチレン・α－オレフィン共重合体Ａを、エチレン・α－オレフィン共重合体Ｃ（メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体、ＭＦＲ：１０ｇ／１０ｍｉｎ、融点：６０℃、密度：０．８８ｇ／ｃｍ３に変えたこと以外は分子鎖連結ポリマー１と同様にして分子鎖連結ポリマー７を得た。
　分子鎖連結反応を行う前のエチレン・α－オレフィン共重合体Ｃの８０℃での伸長粘度は１０ｋＰａ・ｓであった。分子鎖連結ポリマー７の８０℃での伸長粘度は６００ｋＰａ・ｓであった。 (1-2) Molecular chain linking polymer 7
The ethylene / α-olefin copolymer A is converted into an ethylene / α-olefin copolymer C (a linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst, MFR: 10 g / 10 min, melting point: Molecular chain-linked polymer 7 was obtained in the same manner as molecular chain-linked polymer 1, except that the temperature was changed to 60 ° C. and density: 0.88 g / cm 3 .
The elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer C before the molecular chain linking reaction was 10 kPa · s. The elongational viscosity at 80 ° C. of the molecular chain-linked polymer 7 was 600 kPa · s.
　（１－３）分子鎖連結ポリマー８
　上記エチレン・α－オレフィン共重合体Ａを、エチレン・α－オレフィン共重合体Ｄ（メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体、ＭＦＲ：１２ｇ／１０ｍｉｎ、融点：６０℃、密度：０．８８ｇ／ｃｍ３に変えたこと以外は分子鎖連結ポリマー１と同様にして分子鎖連結ポリマー８を得た。 (1-3) Molecular chain linking polymer 8
The ethylene / α-olefin copolymer A is converted into an ethylene / α-olefin copolymer D (a linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst, MFR: 12 g / 10 min, melting point: Molecular chain-linked polymer 8 was obtained in the same manner as molecular chain-linked polymer 1, except that the temperature was changed to 60 ° C. and density: 0.88 g / cm 3 .
　分子鎖連結反応を行う前のエチレン・α－オレフィン共重合体Ｄの８０℃での伸長粘度は６ｋＰａ・ｓであった。分子鎖連結ポリマー８の８０℃での伸長粘度は５００ｋＰａ・ｓであった。 The elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer D before the molecular chain linking reaction was 6 kPa · s. The elongational viscosity at 80 ° C. of the molecular chain linked polymer 8 was 500 kPa · s.
　（１－４）分子鎖連結ポリマー９
　上記エチレン・α－オレフィン共重合体Ａを、エチレン・α－オレフィン共重合体Ｅ（メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体、ＭＦＲ：１ｇ／１０ｍｉｎ、融点：６０℃、密度：０．８８ｇ／ｃｍ３に変えたこと以外は分子鎖連結ポリマー１と同様にして分子鎖連結ポリマー９を得た。
　分子鎖連結反応を行う前のエチレン・α－オレフィン共重合体Ｅの８０℃での伸長粘度は２００ｋＰａ・ｓであった。分子鎖連結ポリマー９の８０℃での伸長粘度は６０００ｋＰａ・ｓであった。 (1-4) Molecular chain-linked polymer 9
The ethylene / α-olefin copolymer A was converted into an ethylene / α-olefin copolymer E (a linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst, MFR: 1 g / 10 min, melting point: Molecular chain-linked polymer 9 was obtained in the same manner as molecular chain-linked polymer 1, except that the temperature was changed to 60 ° C. and density: 0.88 g / cm 3 .
The elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer E before the molecular chain linking reaction was 200 kPa · s. The elongational viscosity at 80 ° C. of the molecular chain-linked polymer 9 was 6000 kPa · s.
　（２）電離放射線の照射による調製
　（２－１）分子鎖連結ポリマー４～６
　（１）と同じエチレン・α－オレフィン共重合体Ａに下記電離放射線を照射することにより、エチレン・α－オレフィン共重合体Ａを分子鎖連結反応させた。これにより、分子鎖連結ポリマー（エチレン・α－オレフィン共重合体Ａ’）４～６を得た。照射条件は以下のとおりである。
　・分子鎖連結ポリマー４：１０ｋＧｙ
　・分子鎖連結ポリマー５：１５ｋＧｙ
　・分子鎖連結ポリマー６：２０ｋＧｙ (2) Preparation by irradiation with ionizing radiation (2-1) Molecular chain-linked polymer 4-6
The same ethylene / α-olefin copolymer A as in (1) was irradiated with the following ionizing radiation to cause the ethylene / α-olefin copolymer A to undergo a chain reaction. As a result, molecular chain linked polymers (ethylene / α-olefin copolymer A ′) 4 to 6 were obtained. Irradiation conditions are as follows.
-Molecular chain linked polymer 4: 10 kGy
・ Molecular chain-linked polymer 5: 15 kGy
・ Molecular chain-linked polymer 6: 20 kGy
　分子鎖連結反応を行う前のエチレン・α－オレフィン共重合体Ａの８０℃での伸長粘度は１１０ｋＰａ・ｓであった。分子鎖連結ポリマー４～６の８０℃での伸長粘度はそれぞれ、１０００ｋＰａ・ｓ、２７００ｋＰａ・ｓ、４５００ｋＰａ・ｓであった。また、分子鎖連結ポリマー１～３のＭＦＲはそれぞれ１．２ｇ／１０ｍｉｎ、１ｇ／１０ｍｉｎ、０．９ｇ／１０ｍｉｎであった。 The elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer A before the molecular chain linking reaction was 110 kPa · s. The elongational viscosities of the molecular chain linked polymers 4 to 6 at 80 ° C. were 1000 kPa · s, 2700 kPa · s, and 4500 kPa · s, respectively. The MFRs of the molecular chain linked polymers 1 to 3 were 1.2 g / 10 min, 1 g / 10 min, and 0.9 g / 10 min, respectively.
　（２－２）分子鎖連結ポリマー１０
　上記エチレン・α－オレフィン共重合体Ａを、エチレン・α－オレフィン共重合体Ｃ（メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体、ＭＦＲ：１０ｇ／１０ｍｉｎ、融点：６０℃、密度：０．８８ｇ／ｃｍ３に変えたこと以外は分子鎖連結ポリマー４と同様にして分子鎖連結ポリマー１０を得た。 (2-2) Molecular chain linked polymer 10
The ethylene / α-olefin copolymer A is converted into an ethylene / α-olefin copolymer C (a linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst, MFR: 10 g / 10 min, melting point: Molecular chain linked polymer 10 was obtained in the same manner as molecular chain linked polymer 4 except that the temperature was changed to 60 ° C. and density: 0.88 g / cm 3 .
　分子鎖連結反応を行う前のエチレン・α－オレフィン共重合体Ｃの８０℃での伸長粘度は１０ｋＰａ・ｓであった。分子鎖連結ポリマー１０の８０℃での伸長粘度は６００ｋＰａ・ｓであった。 The elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer C before the molecular chain linking reaction was 10 kPa · s. The extensional viscosity at 80 ° C. of the molecular chain linked polymer 10 was 600 kPa · s.
　（２－３）分子鎖連結ポリマー１１
　上記エチレン・α－オレフィン共重合体Ａを、エチレン・α－オレフィン共重合体Ｄ（メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体、ＭＦＲ：１２ｇ／１０ｍｉｎ、融点：６０℃、密度：０．８８ｇ／ｃｍ３に変えたこと以外は分子鎖連結ポリマー４と同様にして分子鎖連結ポリマー１１を得た。 (2-3) Molecular chain-linked polymer 11
The ethylene / α-olefin copolymer A is converted into an ethylene / α-olefin copolymer D (a linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst, MFR: 12 g / 10 min, melting point: Molecular chain-linked polymer 11 was obtained in the same manner as molecular chain-linked polymer 4 except that the temperature was changed to 60 ° C. and density: 0.88 g / cm 3 .
　分子鎖連結反応を行う前のエチレン・α－オレフィン共重合体Ｄの８０℃での伸長粘度は６ｋＰａ・ｓであった。分子鎖連結ポリマー１１の８０℃での伸長粘度は５００ｋＰａ・ｓであった。 The elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer D before the molecular chain linking reaction was 6 kPa · s. The elongational viscosity at 80 ° C. of the molecular chain linked polymer 11 was 500 kPa · s.
　（２－４）分子鎖連結ポリマー１２
　上記エチレン・α－オレフィン共重合体Ａを、エチレン・α－オレフィン共重合体Ｅ（メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体、ＭＦＲ：１ｇ／１０ｍｉｎ、融点：６０℃、密度：０．８８ｇ／ｃｍ３に変えたこと以外は分子鎖連結ポリマー４と同様にして分子鎖連結ポリマー１２を得た。 (2-4) Molecular chain linked polymer 12
The ethylene / α-olefin copolymer A was converted into an ethylene / α-olefin copolymer E (a linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst, MFR: 1 g / 10 min, melting point: A molecular chain linked polymer 12 was obtained in the same manner as the molecular chain linked polymer 4 except that the density was changed to 60 ° C. and density: 0.88 g / cm 3 .
　分子鎖連結反応を行う前のエチレン・α－オレフィン共重合体Ｅの８０℃での伸長粘度は２００ｋＰａ・ｓであった。分子鎖連結ポリマー１２の８０℃での伸長粘度は６０００ｋＰａ・ｓであった。 The elongation viscosity at 80 ° C. of the ethylene / α-olefin copolymer E before the molecular chain linking reaction was 200 kPa · s. The elongational viscosity at 80 ° C. of the molecular chain linked polymer 12 was 6000 kPa · s.
［２］太陽電池用封止材製造用組成物の調製（混合工程）
　下記表に示す配合で各材料をロールミルに供給し、８０℃において混練して太陽電池用封止材製造用組成物を調製した。 [2] Preparation of composition for producing solar cell encapsulant (mixing step)
Each material was supplied to a roll mill with the composition shown in the following table, and kneaded at 80 ° C. to prepare a composition for producing a solar cell encapsulant.
［３］太陽電池用封止材の作製（成形工程）
　得られた太陽電池用封止材製造用組成物を、８０℃においてカレンダー成形し、放冷後、シート状の太陽電池用封止材（厚さ０．５ｍｍ）を作製した。 [3] Production of solar cell encapsulant (molding process)
The obtained composition for producing a solar cell encapsulant was calendered at 80 ° C., allowed to cool, and then a sheet-like encapsulant for solar cells (thickness 0.5 mm) was produced.
［４］架橋サンプルの作製
　上記太陽電池用封止材を２枚の白板ガラス（厚さ３．２ｍｍ）で挟み、得られた積層体を真空ラミネータで９０℃において真空時間２分、プレス時間８分で圧着した後、１５５℃のオーブン中で３０分間加熱して架橋硬化させることにより、架橋サンプルを作製した。 [4] Preparation of cross-linked sample The solar cell encapsulant is sandwiched between two pieces of white plate glass (thickness: 3.2 mm), and the resulting laminate is vacuum vacuum laminator at 90 ° C. with a vacuum time of 2 minutes and a press time of 8 After crimping in minutes, a crosslinked sample was prepared by heating in an oven at 155 ° C. for 30 minutes for crosslinking and curing.
［５］８０℃伸長粘度（ｋＰａ・ｓ）の測定
　８０℃に加熱した上記太陽電池用封止材組成物を［ＴＡインスツルメント製粘弾性測定機ＡＲＥＳ－Ｇ２］を用いて歪み速度０．０５／ｓで伸ばし、Ｈｅｎｃｋｙ歪み１．０となったときの値を８０℃伸長粘度（ｋＰａ・ｓ）とした。８０℃における伸長粘度が１００ｋＰａ・ｓ以上の場合にはシート切れやダレが発生することなく安定的に太陽電池用封止材を製造可能であることが認められた。 [5] Measurement of 80 ° C. Elongation Viscosity (kPa · s) The above solar cell encapsulant composition heated to 80 ° C. was strained at a strain rate of 0. 0 using [TA Instruments viscoelasticity measuring device ARES-G2]. The value when stretched at 05 / s and the Henky strain was 1.0 was defined as 80 ° C. elongational viscosity (kPa · s). When the elongational viscosity at 80 ° C. is 100 kPa · s or more, it was confirmed that a solar cell encapsulant can be stably produced without causing sheet breakage or sagging.
［６］８０℃貯蔵弾性率の測定
　８０℃に加熱した上記太陽電池用封止材組成物を、アルファテクノロジーズ社製粘弾性測定機ＲＰＡ２０００を用いて歪み量１０％、周波数１Ｈｚの条件で、８０℃での貯蔵弾性率を測定した。８０℃での貯蔵弾性率が４０ｋＰａ以下であるものは外観が良好であることが認められた。 [6] Measurement of storage modulus at 80 ° C. The above-mentioned solar cell encapsulant composition heated to 80 ° C. was subjected to 80 conditions under the conditions of 10% strain and 1 Hz frequency using a viscoelasticity measuring machine RPA2000 manufactured by Alpha Technologies. The storage modulus at ° C was measured. Those having a storage elastic modulus at 80 ° C. of 40 kPa or less were found to have good appearance.
［７］ゲル分率の測定
　上記太陽電池用封止膜を秤量し［Ａ（ｇ）］、これを１２０℃のキシレン中に２４時間浸漬して不溶解分を２００メッシュの金網で濾過し、金網上の残渣を真空乾燥して乾燥残渣の重量を測定し［Ｂ（ｇ）］、下記式によりゲル分率を算出した。
　　　ゲル分率（質量％）＝（Ｂ／Ａ）×１００ [7] Measurement of gel fraction The solar cell sealing film was weighed [A (g)], immersed in xylene at 120 ° C. for 24 hours, and the insoluble matter was filtered through a 200-mesh wire mesh, The residue on the wire mesh was vacuum dried, the weight of the dried residue was measured [B (g)], and the gel fraction was calculated by the following formula.
Gel fraction (mass%) = (B / A) × 100
［８］外観の評価
　上記太陽電池用封止材の外観の評価を目視により行った。表面割れが発生したものを×とし、表面割れが若干改善したものを△とし、表面荒れが良好に改善したと認められた例を○とし、表面荒れが顕著に改善したと認められた例を◎と評価した。 [8] Evaluation of appearance The appearance of the solar cell encapsulant was evaluated visually. Examples where surface cracks occurred were marked with x, those with slightly improved surface cracks were marked with △, examples where the surface roughness was found to have improved satisfactorily, and examples where the surface roughness was found to be markedly improved Evaluated as.
［９］加工性の評価
　上記混練シートの製造時にシート切れやダレが生じたものを×とした。シート切れやダレがほとんど認められなかったものを○、シート切れやダレが全く認められなかったものを◎とした。なお、２種のポリマーを混合する時に流動性の違いが大きすぎて、そもそも混合が十分できない場合も加工性の評価では×とした。 [9] Evaluation of workability A case where sheet breakage or sagging occurred during the production of the kneaded sheet was evaluated as x. The case where almost no sheet breakage or sagging was observed was marked with ◯, and the sheet with no sheet cutting or sagging was marked with ◎. In addition, when the two types of polymers were mixed, the difference in fluidity was too great, and even when mixing was not possible in the first place, the evaluation of workability was evaluated as x.
［１０］光線透過率の評価
　上記架橋サンプルについて、分光光度計（日立製作所製、Ｕ－４１００）を用いて４００～１０００ｎｍのスペクトル測定を実施し、その平均値を光線透過率（％）とした。 [10] Evaluation of light transmittance The above-mentioned crosslinked sample was subjected to spectrum measurement at 400 to 1000 nm using a spectrophotometer (manufactured by Hitachi, Ltd., U-4100), and the average value was defined as light transmittance (%). .
［１１］ＨＡＺＥの評価
　上記架橋サンプルについて、ＪＩＳ　Ｋ　７１０５（２０００年）に従って、ヘイズメーター（日本電色工業株式会社製 ＮＤＨ ２０００型）を用いてヘイズ値（％）を測定した。 [11] Evaluation of HAZE About the said crosslinked sample, haze value (%) was measured using the haze meter (Nippon Denshoku Industries Co., Ltd. NDH 2000 type | mold) according to JISK7105 (2000).
［１２］屈折率の測定
　各ポリマーについて屈折率をＪＩＳ　Ｋ７１４２に従って測定した。 [12] Measurement of refractive index The refractive index of each polymer was measured according to JIS K7142.
　結果を下記表に示す。なお、各材料の詳細は以下のとおりである。分子鎖連結ポリマー１～１２は上述している。 The results are shown in the table below. The details of each material are as follows. The molecular chain linked polymers 1 to 12 are described above.
　・ベースポリマー１：メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体（カーネルＫＳ３４１Ｔ、日本ポリエチレン社製、ランダム共重合体、非晶性）
　　ＭＦＲ：３．５ｇ／１０ｍｉｎ
　　融点：６０℃
　　密度：０．８８０ｇ／ｃｍ３
　　８０℃における伸長粘度：１１０ｋＰａ・ｓ Base polymer 1: linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst (Kernel KS341T, manufactured by Nippon Polyethylene Co., Ltd., random copolymer, amorphous)
MFR: 3.5g / 10min
Melting point: 60 ° C
Density: 0.880 g / cm 3
Elongation viscosity at 80 ° C: 110 kPa · s
・ベースポリマー２：メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体（カーネルＫＪ６４０Ｔ、日本ポリエチレン社製、ランダム共重合体、非晶性）エチレン・α－オレフィン共重合体Ｂとして
　　ＭＦＲ：３０ｇ／１０ｍｉｎ
　　融点：５８℃
　　密度：０．８８０ｇ／ｃｍ３
　　８０℃における伸長粘度：０．０３ｋＰａ・ｓ Base polymer 2: Linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst (Kernel KJ640T, manufactured by Nippon Polyethylene Co., Ltd., random copolymer, amorphous) ethylene / α-olefin copolymer As B MFR: 30g / 10min
Melting point: 58 ° C
Density: 0.880 g / cm 3
Elongation viscosity at 80 ° C: 0.03 kPa · s
　・ベースポリマー３：メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体
　　ＭＦＲ：６５ｇ／１０ｍｉｎ
　　融点：６０℃
　　密度：０．８８ｇ／ｃｍ３
　　８０℃における伸長粘度：０．０１ｋＰａ・ｓ Base polymer 3: linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst MFR: 65 g / 10 min
Melting point: 60 ° C
Density: 0.88 g / cm 3
Elongation viscosity at 80 ° C: 0.01 kPa · s
　・ベースポリマー４：メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体
　　ＭＦＲ：２０ｇ／１０ｍｉｎ
　　融点：６０℃
　　密度：０．８８ｇ／ｃｍ３
　　８０℃における伸長粘度：０．１ｋＰａ・ｓ Base polymer 4: linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst MFR: 20 g / 10 min
Melting point: 60 ° C
Density: 0.88 g / cm 3
Elongation viscosity at 80 ° C: 0.1 kPa · s
　・ベースポリマー５：メタロセン触媒を用いて重合された直鎖状エチレン・α－オレフィン共重合体
　　ＭＦＲ：５０ｇ／１０ｍｉｎ
　　融点：６０℃
　　密度：０．８８ｇ／ｃｍ３
　　８０℃における伸長粘度：０．０１ｋＰａ・ｓ Base polymer 5: linear ethylene / α-olefin copolymer polymerized using a metallocene catalyst MFR: 50 g / 10 min
Melting point: 60 ° C
Density: 0.88 g / cm 3
Elongation viscosity at 80 ° C: 0.01 kPa · s
　・架橋剤：２，５－ジメチル－２，５－ジ（ｔ－ブチルパーオキシ）ヘキサン
　・シランカップリング剤：γ－メタクリロキシプロピルトリメトキシシラン ・ Crosslinking agent: 2,5-dimethyl-2,5-di (t-butylperoxy) hexane ・ Silane coupling agent: γ-methacryloxypropyltrimethoxysilane
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　＜評価結果＞
　太陽電池用封止材製造用組成物の８０℃貯蔵弾性率が４０ｋＰａを超えた場合は外観に劣ることが認められた。太陽電池用封止材製造用組成物８０℃貯蔵弾性率が４０ｋＰａ以下の場合であってもゲル分率が０％を超えるものは外観に劣ることが認められた。８０℃伸長粘度が１００ｋＰａ・ｓ未満の場合は加工性に劣ることが認められた。電離放射線により分子鎖連結反応を行った場合は透明性に優れることが認められた。 <Evaluation results>
When the 80 degreeC storage elastic modulus of the composition for solar cell sealing material manufacturing exceeds 40 kPa, it was recognized that it is inferior to an external appearance. Even when the 80 ° C. storage elastic modulus of the composition for producing a solar cell encapsulant was 40 kPa or less, it was recognized that the gel fraction exceeding 0% was inferior in appearance. When the 80 ° C. extensional viscosity was less than 100 kPa · s, it was recognized that the processability was poor. It was confirmed that the molecular chain linking reaction by ionizing radiation was excellent in transparency.
　１１　表面側透明保護部材
　１２　裏面側保護部材
　１３Ａ　表面側封止材
　１３Ｂ　裏面側封止材
　１４　太陽電池素子
　１５　接続タブ DESCRIPTION OF SYMBOLS 11 Surface side transparent protective member 12 Back surface side protective member 13A Surface side sealing material 13B Back surface side sealing material 14 Solar cell element 15 Connection tab

Claims (13)

  1. 　メルトフローレート（ＭＦＲ）の異なる２種のエチレン・α－オレフィン共重合体Ａ及びＢの混合物を含む太陽電池用封止膜の製造方法であって、
    　ＭＦＲ（ＪＩＳ　Ｋ７２１０に準拠、温度１９０℃、荷重２．１６ｋｇの条件にて測定。以下同じ。）が２～５ｇ／１０ｍｉｎであるエチレン・α－オレフィン共重合体Ａをそのゲル分率が上がらない範囲で分子同士を連結反応させることにより、溶融状態の８０℃における伸長粘度（歪み速度０．０５／ｓの条件にて、Ｈｅｎｃｋｙ歪みが１．０となったときの粘度。以下同じ。）が５５０～５０００ｋＰａ・ｓであるエチレン・α－オレフィン共重合体Ａ’を得る分子鎖連結工程；
    　エチレン・α－オレフィン共重合体Ａ’を、ＭＦＲが２０～５０ｇ／１０ｍｉｎであるエチレン・α－オレフィン共重合体Ｂと混合することにより、８０℃における伸長粘度が１００ｋＰａ・ｓ以上であり且つ８０℃における貯蔵弾性率（ＪＩＳ　Ｋ７２４４に準拠して、歪み量１０％、周波数１Ｈｚの条件にて測定。以下同じ。）が４０ｋＰａ以下である太陽電池用封止材製造用組成物を得る混合工程；及び
    　前記太陽電池用封止材製造用組成物をシート状に成形して太陽電池用封止材を得る成形工程；
    を含む太陽電池用封止材の製造方法。     A method for producing a sealing film for a solar cell comprising a mixture of two ethylene / α-olefin copolymers A and B having different melt flow rates (MFR),
    The gel fraction of the ethylene / α-olefin copolymer A having an MFR (conforming to JIS K7210, measured at a temperature of 190 ° C. and a load of 2.16 kg, the same applies hereinafter) of 2 to 5 g / 10 min does not increase. By allowing the molecules to undergo a ligation reaction within a range, the extensional viscosity at 80 ° C. in a molten state (viscosity when Henky strain becomes 1.0 under the condition of strain rate 0.05 / s, the same applies hereinafter). A molecular chain linking step to obtain an ethylene / α-olefin copolymer A ′ having a viscosity of 550 to 5000 kPa · s;
    By mixing the ethylene / α-olefin copolymer A ′ with the ethylene / α-olefin copolymer B having an MFR of 20 to 50 g / 10 min, the elongational viscosity at 80 ° C. is 100 kPa · s or more and 80 A mixing step of obtaining a composition for producing a solar cell encapsulant having a storage elastic modulus at ℃ (measured in accordance with JIS K7244 under the conditions of a strain of 10% and a frequency of 1 Hz; the same shall apply hereinafter); And a molding step of obtaining the solar cell sealing material by molding the composition for manufacturing the solar cell sealing material into a sheet shape;
    The manufacturing method of the sealing material for solar cells containing.
  2. 　前記分子鎖連結工程は、エチレン・α－オレフィン共重合体Ａに有機過酸化物を添加した後、加熱して該有機過酸化物を分解させることにより行う、請求項１に記載の方法。 The method according to claim 1, wherein the molecular chain linking step is performed by adding an organic peroxide to the ethylene / α-olefin copolymer A and then heating to decompose the organic peroxide.
  3. 　前記加熱は、エチレン・α－オレフィン共重合体Ａと前記有機過酸化物との混合時の加熱により行う、請求項２に記載の方法。 The method according to claim 2, wherein the heating is performed by heating during mixing of the ethylene / α-olefin copolymer A and the organic peroxide.
  4. 　前記分子鎖連結工程は、前記エチレン・α－オレフィン共重合体Ａに電離放射線を照射することにより行う、請求項１に記載の方法。 The method according to claim 1, wherein the molecular chain linking step is performed by irradiating the ethylene / α-olefin copolymer A with ionizing radiation.
  5. 　エチレン・α－オレフィン共重合体Ｂの８０℃における伸長粘度が０．０１～５０ｋＰａ・ｓである、請求項１～４のいずれか１項に記載の方法。 The method according to any one of claims 1 to 4, wherein the ethylene / α-olefin copolymer B has an extensional viscosity at 80 ° C of 0.01 to 50 kPa · s.
  6. 　エチレン・α－オレフィン共重合体Ａ’のＭＦＲが０．１～３．５ｇ／１０ｍｉｎである、請求項１～５のいずれか１項に記載の方法。 The method according to any one of claims 1 to 5, wherein the MFR of the ethylene / α-olefin copolymer A 'is 0.1 to 3.5 g / 10 min.
  7. 　前記太陽電池用封止材製造用組成物におけるエチレン・α－オレフィン共重合体Ａ’及びＢの合計量１００質量部を基準として、エチレン・α－オレフィン共重合体Ａ’の含有量が１０～７５質量部であり、エチレン・α－オレフィン共重合体Ｂの含有量が２５～９０質量部である、請求項１～６のいずれか１項に記載の方法。 The ethylene / α-olefin copolymer A ′ content in the composition for producing a solar cell encapsulant is 100 to 10 parts by mass based on the total amount of ethylene / α-olefin copolymer A ′ and B of 10 to 10 parts by mass. The method according to any one of claims 1 to 6, wherein the content of the ethylene / α-olefin copolymer B is 75 to 50 parts by mass and 25 to 90 parts by mass.
  8. 　前記成形工程をカレンダー成形により行う、請求項１～７のいずれか１項に記載の方法。 The method according to any one of claims 1 to 7, wherein the molding step is performed by calendar molding.
  9. 　溶融状態の８０℃における伸長粘度が５５０～５０００ｋＰａであり且つＭＦＲが０．１～３．５ｇ／１０ｍｉｎであるエチレン・α－オレフィン共重合体Ａ’と、ＭＦＲが２０～５０ｇ／１０ｍｉｎであるエチレン・α－オレフィン共重合体Ｂとの樹脂混合物を含み、
    　８０℃における伸長粘度が１００ｋＰａ・ｓ以上であり且つ８０℃における貯蔵弾性率が４０ｋＰａ以下である太陽電池用封止材製造用組成物。     An ethylene / α-olefin copolymer A ′ having an elongation viscosity at 80 ° C. in a molten state of 550 to 5000 kPa and an MFR of 0.1 to 3.5 g / 10 min, and ethylene having an MFR of 20 to 50 g / 10 min A resin mixture with α-olefin copolymer B,
    A composition for producing a sealing material for solar cells, which has an elongational viscosity at 80 ° C. of 100 kPa · s or more and a storage elastic modulus at 80 ° C. of 40 kPa or less.
  10. 　エチレン・α－オレフィン共重合体Ｂの８０℃における伸長粘度が０．０１～５０ｋＰａ・ｓである、請求項９に記載の太陽電池用封止材製造用組成物。 10. The composition for producing a sealing material for a solar cell according to claim 9, wherein the ethylene / α-olefin copolymer B has an extensional viscosity at 80 ° C. of 0.01 to 50 kPa · s.
  11. 　エチレン・α－オレフィン共重合体Ａ’及びＢの合計量１００質量部を基準として、前記エチレン・α－オレフィン共重合体Ａ’の含有量が１０～７５質量部であり、エチレン・α－オレフィン共重合体Ｂの含有量が２５～９０質量部である、請求項８又は９に記載の太陽電池用封止材製造用組成物。 The content of the ethylene / α-olefin copolymer A ′ is 10 to 75 parts by mass based on 100 parts by mass of the total amount of the ethylene / α-olefin copolymers A ′ and B, and the ethylene / α-olefin The composition for producing a sealing material for a solar cell according to claim 8 or 9, wherein the content of the copolymer B is 25 to 90 parts by mass.
  12. 　請求項９～１１のいずれか１項に記載の太陽電池用封止材組成物がシート状に成形された太陽電池用封止材。 A solar cell encapsulant, wherein the solar cell encapsulant composition according to any one of claims 9 to 11 is formed into a sheet shape.
  13. 　表面側保護部材、太陽電池素子及び裏面側保護部材を有する太陽電池モジュールであって、
    　前記太陽電池素子が請求項１２に記載の太陽電池用封止材により封止されている太陽電池モジュール。     A solar cell module having a front surface side protective member, a solar cell element and a back side protective member,
    The solar cell module with which the said solar cell element is sealed with the sealing material for solar cells of Claim 12.
PCT/JP2016/080103 2015-12-04 2016-10-11 Method for manufacturing solar cell sealing material and composition for manufacturing solar cell sealing material WO2017094354A1 (en)

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JPH11322862A (en) * 1998-05-22 1999-11-26 Asahi Chem Ind Co Ltd Material for blow molding to produce large-size product, and large-size molded product
WO2011007871A1 (en) * 2009-07-17 2011-01-20 三菱樹脂株式会社 Solar cell sealing material and solar cell module produced using the same
JP2013159673A (en) * 2012-02-03 2013-08-19 Mitsui Chemicals Inc Solar cell encapsulant and solar cell module

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JPH11322862A (en) * 1998-05-22 1999-11-26 Asahi Chem Ind Co Ltd Material for blow molding to produce large-size product, and large-size molded product
WO2011007871A1 (en) * 2009-07-17 2011-01-20 三菱樹脂株式会社 Solar cell sealing material and solar cell module produced using the same
JP2013159673A (en) * 2012-02-03 2013-08-19 Mitsui Chemicals Inc Solar cell encapsulant and solar cell module

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Publication number Priority date Publication date Assignee Title
CN112662047A (en) * 2020-04-16 2021-04-16 株式会社Lg化学 Composition for sealing material film containing ethylene/alpha-olefin copolymer and sealing material film containing same
CN112662047B (en) * 2020-04-16 2024-02-06 株式会社Lg化学 Composition for sealing material film comprising ethylene/alpha-olefin copolymer and sealing material film comprising same

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