JP2012015346A - Resin composition for solar cell sealing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for solar cell sealing material which can improve initial conversion efficiency while minimizing ultraviolet degradation of resin due to wavelength conversion by containing an ethylene copolymer, a layered complex metal compound and/or its baked product and a benzophenone based compound, and can minimize generation of acid incident to degradation of resin, and decrease in adhesion to a protective member or decrease in conversion efficiency over time due to capturing of steam entering a module.SOLUTION: The resin composition for solar cell sealing material contains an ethylene copolymer (A), a layered complex metal compound (B) and/or its baked product (C), and a benzophenone based compound (D).

Description

  The present invention relates to a resin composition for a solar cell encapsulant used for a solar cell encapsulant.

  In recent years, there has been a social demand for the practical use and expansion of inexhaustible and clean solar power generation systems from the perspective of denuclear power generation policy, response to soaring crude oil, depletion of fossil fuels and global environmental conservation. Yes. The main solar power generation systems currently introduced are composed of silicon solar cell modules such as crystalline silicon and amorphous silicon, compound semiconductor systems such as CdTe and CIGS, and peripheral devices. Cost reduction is the biggest issue for introduction. Although the cost has been significantly reduced over the past few years, the current power generation cost is still relatively high compared to other energy sources, and there is a need for technological developments such as higher efficiency and longer life of solar cells. It has been.

On the other hand, in order to increase the efficiency and life of solar cell modules, it is necessary to improve various performances such as light receiving property, transparency, weather resistance, water resistance, adhesion, corrosion resistance, heat resistance, etc. These performances are also required for sealing materials that protect the environment from the environment (see Patent Documents 1, 2, 3, and 4).
However, since many sealing materials use an ethylene vinyl acetate copolymer having high transparency, it is difficult to significantly improve transparency. In addition, due to the characteristics of the power generation element, the ultraviolet ray region of sunlight has a low power generation contribution rate, so that sunlight cannot be effectively used. Furthermore, the ethylene vinyl acetate copolymer induces acid generation due to resin deterioration due to water, heat, etc., corrosion of electrode wiring due to the generated acid, and reduced adhesion to the protective member, leading to a decrease in conversion efficiency. There's a problem.

  Therefore, Patent Documents 5 and 6 disclose a sealing material and a solar cell in which an organic metal complex that absorbs ultraviolet light and emits light in the visible region is blended to improve conversion efficiency. Patent Documents 7 and 8 disclose transparent films in which acid acceptor particles having an average particle size of 5 μm or less are dispersed in an ethylene vinyl acetate copolymer to suppress generation of acid.

  However, in Patent Documents 5 and 6, since the durability of the organometallic complex is poor, a rapid decrease in conversion efficiency occurs along with the accelerated test, and it has not yet been put to practical use. Furthermore, many organic compounds serving as ligands have insufficient absorption spectrum intensity in the ultraviolet region of 280 to 400 nm, and only a part of the ultraviolet light can be converted into visible light. For this reason, it is necessary to add an ultraviolet absorber that prevents deterioration of the resin constituting the encapsulant, which may be an inhibiting factor of the light emission process, and efficient light emission may not be possible. Further, in Patent Documents 7 and 8, since the difference in refractive index between the resin and the acid acceptor is large, light scattering occurs at the interface between the resin and the acid acceptor, resulting in insufficient transparency and light receiving property to the power generation element. Efficiency and longevity have not been achieved.

JP H08-148708 JP 2000-183382 A JP 2005-126708 A JP 2008-53379 A JP 2001-308365 A JP 2007-230955 A JP 2005-29588 A JP 2008-115344 A

  When used as a solar cell encapsulant, the present invention greatly improves the conversion efficiency of solar cells, reduces the adhesion over time due to the generation of acid accompanying resin degradation and the capture of water that has entered the solar cell module An object of the present invention is to provide a resin composition for a solar cell encapsulant and a solar cell encapsulant that can suppress the decrease in conversion efficiency and further suppress the decrease in conversion efficiency.

  In the present invention, the first invention includes an ethylene copolymer (A), a layered composite metal compound (B) and / or a fired product (C) thereof, and a benzophenone compound (D). It is related with the resin composition for solar cell sealing materials.

2nd invention is related with the resin composition for solar cell sealing materials of the said invention, wherein a layered composite metal compound (B) is represented by following General formula (2).
Mg _1-a · Al _a (OH) ₂ · An ^n- _{a / n} · cH ₂ O General formula (1)
(0.2 ≦ a ≦ 0.35, 0 ≦ c ≦ 1, An: n-valent anion)

3rd invention is related with the resin composition for solar cell sealing materials of the said invention, wherein a layered composite metal compound (B) is represented by following General formula (2).
(M _a Mg _1-a ) _1-b · Al _b (OH) ₂ · An ^n- _{b / n} · cH ₂ O General formula (2)
(M represents a metal selected from Ni, Zn, Cu and Ca, and a, b and c are the formulas 0 ≦ a ≦ 1, 0.2 ≦ b ≦ 0.35, 0 ≦ c ≦ 1, An: n-valent anion)

  4th invention is related with the resin composition for solar cell sealing materials of the said invention, wherein benzophenone type compound (D) is melting | fusing point 25-120 degreeC.

  The fifth invention is a resin composition for a solar cell encapsulant of the above invention, wherein the fired product (C) is a fired product obtained by heat-treating the layered composite metal compound (B) at 200 to 800 ° C. Related to things.

6th invention is related with the resin composition for solar cell sealing materials of the said invention, wherein a layered composite metal compound (B) is a BET specific surface area of 1-200 m < ² > / g.

  In the seventh invention, the ethylene copolymer (A) comprises an ethylene vinyl acetate copolymer, an ethylene methyl acrylate copolymer, an ethylene ethyl acrylate copolymer, an ethylene methyl methacrylate copolymer, and an ethylene methacrylic acid. It is related with the resin composition for solar cell sealing materials of the said invention characterized by being 1 or more types of copolymers selected from the group which consists of an ethyl copolymer.

  In an eighth invention, 0.01 to 15 parts by weight of a layered composite metal compound (B) and / or a fired product (C) thereof is added to 100 parts by weight of an ethylene copolymer (A), and a benzophenone compound (D ) Is used in an amount of 0.01 to 15 parts by weight.

The ninth invention is a resin composition for a solar cell encapsulant according to the above invention, wherein the benzophenone compound (D) has a molar extinction coefficient of 1000 to 15000 (l · mol ⁻¹ · cm ⁻¹ ) at 340 nm. Related to things.

A tenth invention is a solar cell encapsulant formed by using an ethylene copolymer (A), a layered composite metal compound (B) and / or a fired product thereof (C), and a benzophenone compound (D). Stopping material,
The layered composite metal compound (B) is a compound represented by the following general formula (1) or the following general formula (2), and the fired product (C) converts the layered composite metal compound (B) from 200 to 200. It is related with the solar cell sealing material characterized by being a baked material heat-processed at 800 degreeC.
Mg _1-a · Al _a (OH) ₂ · An ^n- _{a / n} · cH ₂ O General formula (1)
(0.2 ≦ a ≦ 0.35, 0 ≦ c ≦ 1, An: n-valent anion)
(M _a Mg _1-a ) _1-b · Al _b (OH) ₂ · An ^n- _{b / n} · cH ₂ O General formula (2)
(M represents a metal selected from Ni, Zn, Cu and Ca, and a, b and c are the formulas 0 ≦ a ≦ 1, 0.2 ≦ b ≦ 0.35, 0 ≦ c ≦ 1, An: n-valent anion)

  The eleventh invention relates to a solar cell encapsulant formed by using an ethylene vinyl acetate copolymer and the solar cell encapsulant resin composition of the above invention.

  The twelfth invention is characterized in that 0.5 to 2000 parts by weight of the benzophenone compound (D) is used with respect to 100 parts by weight of the layered composite metal compound (B) and / or the fired product (C) thereof. The present invention relates to a solar cell encapsulant of the invention.

  A thirteenth invention relates to a solar cell module formed by using the resin composition for solar cell sealing material of the above invention.

  The fourteenth invention relates to a solar cell module formed by using the solar cell sealing material of the invention described above.

  By the wavelength conversion effect according to the present invention, it is possible to simultaneously suppress the UV deterioration of the resin and improve the initial conversion efficiency, the transparency is good, the acid and water trapping prevents the deterioration of the adhesion with the protective member over time and the conversion efficiency. The resin composition for solar cell sealing materials which can form the solar cell sealing material which suppresses the fall of this, and the solar cell sealing material were able to be provided.

It is explanatory drawing for showing a solar cell module sample. It is explanatory drawing for showing the sample for an endurance test. It is explanatory drawing for showing the sample for an endurance test. It is explanatory drawing for showing the sample for an endurance test.

The present invention will be described in detail.
The resin composition for a solar cell encapsulant of the present invention contains an ethylene copolymer (A), a layered composite metal compound (B) and / or a fired product (C) thereof, and a benzophenone compound (D). This is very important.

In the present invention, the layered composite metal compound (B) and / or the fired product (C) thereof and the benzophenone compound (D) are combined to emit light, and the conversion efficiency of the solar cell receiving the light emission is greatly improved. I found a surprising effect.
Considering this improvement in conversion efficiency, the benphenone compound (D) absorbs light in the ultraviolet region, enters the excited state, and goes through a stabilization process due to thermal deactivation when returning to the ground state. However, in the present invention, a chemical bond is formed between the benzophenone compound (D) and the layered composite metal compound (B) and / or a fired product (C) thereof. It is inferred that a large energy band was formed. Then, charge transfer from the excited state of the benzophenone-based compound to a new energy band occurs, and the stabilization process is performed by light emission in the visible region of 400 to 600 nm, thereby increasing the amount of light received by the solar cell. The initial conversion efficiency is estimated to be improved.

  In the present invention, the benzophenone compound (D) preferably has a melting point of 25 to 120 ° C, more preferably 25 to 105 ° C. When the temperature exceeds 120 ° C., the benzophenone-based compound does not dissolve at the time of molding the resin composition but dissolves at the time of cross-linking in the laminating process, resulting in non-uniform dispersion in the resin and the coexistence probability with the layered composite metal compound. The wavelength conversion effect may be reduced. Moreover, when it is less than 25 degreeC, the bleed-out from a solar cell sealing material becomes remarkable, and when manufacturing a solar cell, there exists a possibility of reducing adhesiveness with glass or a back surface protection member. The melting point of the benzophenone compound is the average value of the values measured three times with a melting point measuring device.

In the present invention, the molar extinction coefficient at 340 nm of the benzophenone compound (D) is preferably 1000 to 15000 (l · mol ⁻¹ · cm ⁻¹ ). If it is less than 1000, the absorption efficiency per weight of the benzophenone compound may be poor, and the light emission efficiency may also be deteriorated. In addition, a large amount of addition is required to suppress resin deterioration, and there is a risk of bleeding out. When it exceeds 15000, energy transfer occurs between benzophenone-based compounds, and the light emission efficiency may decrease. The molar extinction coefficient is a spectrum chart obtained by adjusting an ethanol solution having a concentration of 5 × 10 ⁻⁵ mol / l and measuring a UV spectrum using a spectrophotometer UV-3600 manufactured by Shimadzu Corporation in a 1 cm quartz cell. Calculated from

  In the present invention, the benzophenone compound (D) is preferably used in an amount of 0.01 to 15 parts by weight with respect to 100 parts by weight of the ethylene copolymer (A). And for example, when manufacturing the resin composition for solar cell sealing materials of a high concentration compounded product like a masterbatch, it is preferable to use 5-15 weight part. Manufacturing a solar cell encapsulant using a masterbatch is preferable from the viewpoints of economy and handling. On the other hand, for example, in the case of a resin composition for a solar cell encapsulant other than a masterbatch, 0.01 to 2.5 parts by weight is preferable in the case of a benzophenone-based compound from the viewpoint of wavelength conversion efficiency. If the upper limit of the amount used is exceeded, there is a risk of poor appearance due to bleed-out or a decrease in adhesion to glass or a back surface protective member.

  In the present invention, the benzophenone compound (D) specifically includes, for example, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone. 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-n-octadecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2- Hydroxy-5-chlorobenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2 ', 4,4' -Tetrahydroxybenzofe Emissions, and the like. Among them, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone in terms of conversion efficiency Is preferred.

In the present invention, the layered composite metal compound (B) and the fired product (C) are compounds in a layered form having interlayer ion exchange properties and neutralization reactivity with acids. And when used in a solar cell module, water that has penetrated into the solar cell encapsulant, and acid generated by hydrolysis of the ethylene vinyl acetate copolymer due to deterioration, etc. are taken in between the layers, and by neutralization An effect of preventing deterioration of the solar cell sealing material and the power generation element is obtained (hereinafter also referred to as an acid / water capturing effect).
The acid / water trapping effect is determined by the charge density of ions entering the interlayer, and anions having a higher valence and a smaller ionic radius are more likely to be trapped between the layers.
In addition to the layered composite metal compound, metal oxides, metal hydroxides, metal carbonates, and the like are known as the compound having an acid / water scavenging effect, and many of these compounds have a high refractive index. For this reason, when added to the ethylene copolymer, the difference in refractive index from the ethylene copolymer becomes large, causing light scattering and reflection to become opaque, resulting in a decrease in conversion efficiency. The effect of the layered composite metal compound in the present invention was to improve transparency and improve the efficiency of the acid / water scavenging effect, and to suppress the decrease in adhesion and the conversion efficiency with the protective member over time.

  In the present invention, the layered composite metal compound (B) is preferably a general natural hydrotalcite or a synthesized hydrotalcite.

  In the present invention, the fired product (C) can be produced by firing the layered composite metal compound (B). This fired product (C) exhibits a higher acid / water scavenging effect than the layered composite metal compound (B). In addition, the fired product (C) captures acid and water, thereby changing the chemical composition, lowering the refractive index, and reducing the refractive index difference from the ethylene copolymer (A). It tends to improve.

In the present invention, it is also preferable to use a compound of the following general formula (1) as the layered composite metal compound (B).
Mg _1-a · Al _a (OH) ₂ · An ^n- _{a / n} · cH ₂ O General formula (1)
(0.2 ≦ a ≦ 0.35, 0 ≦ c ≦ 1, An: n-valent anion)

In the general formula (1), the Al content ratio a is preferably 0.2 to 0.35. If it is less than 0.2, it is difficult to produce a layered composite metal compound, and if it exceeds 0.35, the difference in refractive index from the ethylene copolymer (A) may increase and transparency may be insufficient. is there. The water content c is preferably 0 ≦ c ≦ 1. The type of the anion An ⁿ⁻ is not particularly limited, and examples thereof include hydroxide ions, carbonate ions, silicate ions, organic carboxylate ions, organic sulfonate ions, and organic phosphate ions. The index a in the general formula (1) was obtained by dissolving the layered composite metal compound with an acid and analyzing with a “plasma emission spectroscopic analyzer SPS4000 (Seiko Electronics Co., Ltd.)”.

In the present invention, it is also preferable to use a compound of the following general formula (2) as the layered composite metal compound (B).
(M _a Mg _1-a ) _1-b · Al _b (OH) ₂ · An ^n- _{b / n} · cH ₂ O General formula (2)
(M represents a metal selected from Ni, Zn, Cu and Ca, and a, b and c are the formulas 0 ≦ a ≦ 1, 0.2 ≦ b ≦ 0.35, 0 ≦ c ≦ 1, An: n-valent anion)

In the general formula (2), it is important that the Al content ratio a is 0.2 to 0.35. If it is less than 0.2, it is difficult to produce a layered composite metal compound, and if it exceeds 0.35, the difference in refractive index from the ethylene copolymer (A) becomes large and the transparency deteriorates. The water content c is preferably 0 ≦ c ≦ 1. The type of the anion An ⁿ⁻ is not particularly limited, and examples thereof include hydroxide ions, carbonate ions, silicate ions, organic carboxylate ions, organic sulfonate ions, and organic phosphate ions.

In the present invention, layered composite metal compound (B) and its calcined product (C) is preferably a BET specific surface area of ^{1~200m 2 / g, 1~160m 2 /} g is more preferable. If it is less than 1 m ² / g, chemical bonding with the benzophenone compound is unlikely to occur and the light emission intensity may be weak. If it exceeds 200 m ² / g, the basicity of the layered composite metal compound is too strong and the resin is not strong enough. There is a risk of promoting deterioration.

  The solar cell encapsulant resin composition of the present invention uses 0.01 to 15 parts by weight of the layered composite metal compound (B) or the fired product (C) with respect to 100 parts by weight of the ethylene copolymer (A). Is preferred. And for example, when manufacturing the resin composition for solar cell sealing materials of a high concentration compounded product like a masterbatch, it is preferable to use 5-15 weight part. Manufacturing a solar cell encapsulant using a masterbatch is preferable from the viewpoints of dispersion and handling of the layered composite metal compound and the fired product. On the other hand, for example, in the case of a resin composition for a solar cell encapsulant other than a masterbatch, 0.01 to 7 parts by weight is preferable in the case of a layered composite metal compound from the viewpoint of transparency. Moreover, in the case of a baked product, 0.01-5.0 weight part is preferable. If the upper limit of the amount used is exceeded, the transparency becomes insufficient and the initial conversion efficiency may be reduced.

  A method for producing the layered composite metal compound (B) will be described.

  After mixing at least one of an aqueous magnesium salt solution, an aqueous zinc salt solution, an aqueous nickel salt solution, an aqueous calcium salt solution and an alkaline aqueous solution containing an anion and an aqueous aluminum salt solution to obtain a mixed solution having a pH in the range of 8 to 14, The mixed solution can be obtained by aging in the temperature range of 80 to 100 ° C.

  The pH during the ripening reaction is preferably 10 to 14, and more preferably 11 to 14. If the pH is less than 10, a layered composite metal compound having a large plate surface diameter and an appropriate thickness may not be obtained.

  When the aging temperature is less than 80 ° C. and 100 ° C. or more, it becomes difficult to obtain a layered composite metal compound having an appropriate plate surface diameter. A more preferable aging temperature is 85 to 100 ° C.

  The aging time for the aging reaction of the layered composite metal compound is not particularly limited, but is, for example, about 2 to 24 hours. In the case of less than 2 hours, it is difficult to obtain a layered composite metal compound having a large plate surface diameter and an appropriate thickness. Aging over 24 hours is not economical.

  The alkaline aqueous solution containing the anion is preferably a mixed alkaline aqueous solution of an aqueous solution containing an anion and an aqueous alkali hydroxide solution.

  As an aqueous solution containing an anion, aqueous solutions such as sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, organic carboxylate, organic sulfonate, and organic phosphate are preferable.

  As the alkali hydroxide aqueous solution, sodium hydroxide, potassium hydroxide, ammonia, urea aqueous solution and the like are preferable.

  As the metal salt aqueous solution in the present invention, a metal sulfate aqueous solution, a metal chloride aqueous solution, a metal nitrate aqueous solution and the like can be used, and a magnesium chloride aqueous solution is preferable. Further, a slurry of metal oxide powder or metal hydroxide powder may be substituted.

  As the aluminum salt aqueous solution in the present invention, an aluminum sulfate aqueous solution, an aluminum chloride aqueous solution, an aluminum nitrate aqueous solution and the like can be used, and an aluminum sulfate aqueous solution and an aluminum chloride aqueous solution are preferable. A slurry of aluminum oxide powder or aluminum hydroxide powder may be substituted.

  The order of mixing an aqueous alkali solution containing an anion, at least one of magnesium, zinc, nickel and calcium and aluminum is not particularly limited, and each aqueous solution or slurry may be mixed simultaneously. Preferably, an aqueous solution or slurry in which magnesium, zinc, nickel, calcium and aluminum are mixed in advance is added to an aqueous alkali solution containing anions.

  Moreover, when adding each aqueous solution, you may carry out either when adding this aqueous solution at once, or when dripping continuously.

  The pH of the layered composite metal compound represented by the general formulas (1) and (2) is preferably 8.0 to 10.0. When pH is less than 8.0, there exists a possibility that the neutralization efficiency with an acid may become weak. When pH exceeds 10.0, there exists a possibility that an ethylene vinyl acetate copolymer may deteriorate by elution of a metal. The pH of the layered composite metal compound was measured by weighing 5 g of a sample into a 300 ml Erlenmeyer flask, adding 100 ml of boiled pure water, heating and holding the boiled state for about 5 minutes, then plugging it and allowing it to cool to room temperature. Add water corresponding to the weight loss, plug again, shake for 1 minute, let stand for 5 minutes, then measure the pH of the resulting supernatant according to JIS Z8802-7, and obtain the obtained value as a layered composite The pH of the metal compound was used.

  In the production of the fired product (C), the layered composite metal compound (B) is preferably fired at 200 to 800 ° C, more preferably 250 ° C to 700 ° C. The firing time may be adjusted according to the firing temperature, but is preferably 1 to 24 hours, and more preferably 1 to 10 hours. The atmosphere during firing may be an oxidizing atmosphere or a non-oxidizing atmosphere, but it is better not to use a gas having a strong reducing action such as hydrogen.

  The ethylene copolymer (A) used in the present invention is a polymer obtained by mixing two or more monomers, and is not particularly limited as long as at least one of them is an ethylene monomer. Specifically, ethylene vinyl acetate copolymer, ethylene methyl acrylate copolymer, ethylene ethyl acrylate copolymer, ethylene methyl methacrylate copolymer, ethylene ethyl methacrylate copolymer, ethylene vinyl acetate based plural Examples include copolymers, ethylene methyl acrylate multi-component copolymers, ethylene ethyl acrylate multi-component copolymers, ethylene methyl methacrylate multi-component copolymers, ethylene ethyl methacrylate multi-component copolymers, etc. Ethylene with a vinyl acetate content of 15 to 40% from the viewpoint of reducing cell damage, improving transparency, and improving productivity. Vinyl acetate copolymer is preferred, more preferably vinyl vinyl acetate content of 23 to 35% of an ethylene acetate copolymer.

  The production of the resin composition for a solar cell encapsulant of the present invention comprises an ethylene copolymer (A), a layered composite metal compound (B) and / or a fired product (C) thereof, and a benzophenone compound (D). After mixing using a general high-speed shear mixer such as a Henschel mixer, a super mixer, etc., for example, a two-roll, three-roll, pressure kneader, Banbury mixer, single-screw kneading extruder or twin-screw kneading extrusion It can be manufactured by extrusion molding into a pellet after melt-kneading using a machine. Further, the layered composite metal compound (B) or the fired product (C) and the benzophenone-based compound (D) are mixed with a mixer or the like in advance, or subjected to a mechanochemical treatment with a bead mill, a ball mill, or the like. The chemical bond between the compound (B) and the benzophenone compound is increased, and an effective wavelength conversion effect is obtained.

  The resin composition for a solar cell encapsulant of the present invention thus obtained includes a crosslinking agent, a crosslinking aid, a silane coupling agent, a light stabilizer, an antioxidant, a dispersant, a light diffusion as necessary. Additives such as colorants, colorants, and flame retardants can also be blended, and various additives can be blended with ethylene copolymers and layered composite metal compounds to produce final molded products. In addition, it is also possible to add separately.

  When using ethylene vinyl acetate copolymer, the crosslinking agent is used to prevent thermal deformation under high temperature use, and in the case of ethylene vinyl acetate copolymer, organic peroxide is generally used. . Although the addition amount is not particularly limited, it is preferably used in an amount of 0.05 to 3 parts by weight with respect to a total of 100 parts by weight of the ethylene copolymer and the layered composite metal compound. Specific examples include tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-2-ethylhexyl isopropyl carbonate, tert-butyl peroxyacetate, tert-butylcumyl peroxide, 2,5-dimethyl-2,5-di (Tert-butylperoxy) hexane, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 2,5-dimethyl-2,5-di (Tert-butylperoxy) hexane, 1,1-di (tert-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (tert-butylperoxy) cyclohexane, 1,1-di (Tert-hexylperoxy) cyclohexane, 1,1-di tert-amylperoxy) cyclohexane, 2,2-di (tert-butylperoxy) butane, methyl ethyl ketone peroxide, 2,5-dimethylhexyl-2,5-diperoxybenzoate, tert-butyl hydroperoxide, p -Mentane hydroperoxide, dibenzoyl peroxide, p-chlorobenzoyl peroxide, tert-butylperoxyisobutyrate, n-butyl-4,4-di (tert-butylperoxy) valerate, ethyl-3,3 -Di (tert-butylperoxy) butyrate, hydroxyheptyl peroxide, dichlorohexanone peroxide, 1,1-di (tert-butylperoxy) 3,3,5-trimethylcyclohexane, n-butyl-4,4- Te t- butyl peroxy) valerate, 2,2-di (tert- butylperoxy) include butane and the like.

  The crosslinking aid is used to efficiently perform the crosslinking reaction, and examples thereof include polyunsaturated compounds such as polyallyl compounds and polyacryloxy compounds. Although the addition amount is not particularly limited, it is preferably used in an amount of 0.05 to 3 parts by weight with respect to a total of 100 parts by weight of the ethylene copolymer and the layered composite metal compound. Specific examples include triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl fumarate, diallyl maleate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and the like.

  Silane coupling agents are used to improve adhesion to protective materials and solar cell elements, and include unsaturated groups such as vinyl groups, acryloxy groups, and methacryloxy groups, and hydrolyzable groups such as alkoxy groups. The compound which has is mentioned. Although the addition amount is not particularly limited, it is preferably used in an amount of 0.05 to 3 parts by weight with respect to a total of 100 parts by weight of the ethylene copolymer and the layered composite metal compound. Specific examples include vinyltrichlorosilane, vinyltris (βmethoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. , Γ-glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, Examples thereof include N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane.

  The light stabilizer is used in combination with an ultraviolet absorber and used for imparting weather resistance, and includes a hindered amine light stabilizer, and the addition amount is not particularly limited, but the total of the ethylene copolymer and the layered composite metal compound is 100. It is preferable to use 0.01 to 3 parts by weight with respect to parts by weight. Specific examples include dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1,3,3 -Tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {{2,2,6 6-tetramethyl-4-piperidyl) imino}], N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6- Pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) separate, 2- (3,5-di -Tert-4-hydroxybenzyl)- Such -n- butyl malonic acid bis (1,2,2,6,6-pentamethyl-4-piperidyl) can be mentioned.

  Antioxidants are used to impart stability at high temperatures, and include monophenolic, bisphenolic, polymeric phenolic, sulfur-based, phosphoric acid-based and the like. Although the addition amount is not particularly limited, it is preferably used in an amount of 0.05 to 3 parts by weight with respect to a total of 100 parts by weight of the ethylene copolymer and the layered composite metal compound. Specific examples include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, 2,2′-methylene-bis- ( 4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4'-thiobis- (3-methyl-6-tert-butylphenol) 4,4′-butylidene-bis- (3-methyl-6-tert-butylphenol), 3,9-bis [{1,1-dimethyl-2- {β- (3-tert-butyl-4-hydroxy -5-methylphenyl) propionyloxy} ethyl} 2,4,8,10-tetraoxaspiro] 5,5-undecane, 1,1,3-tris- (2-methyl-4-hi Loxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis- {methylene-3 -(3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate} methane, bis {(3,3'-bis-4'-hydroxy-3'-tert-butylphenyl) butyric Acid} glycol ester, dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiopropionate, triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene- Bis- (3-methyl-6-tert-butylphenyl-di-tridecyl) phos Phyto, cyclic neopentanetetrayl bis (octadecyl phosphite), trisdiphenyl phosphite, diisodecenorepentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenalene-10-oxide 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10- Dihydro-9-oxa-10-phosphaphenanthrene, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-) tert-methylphenyl) phosphite, 2,2-methylenebis ( , And a 6-tert-butylphenyl) octyl phosphite.

  The dispersant is used to uniformly disperse the pigment and filler in the ethylene copolymer, and examples thereof include polyethylene wax, ethylene vinyl acetate copolymer wax, and ethylene acrylic acid copolymer wax. Although the addition amount is not particularly limited, it is preferably used in an amount of 5 to 1000 parts by weight with respect to 100 parts by weight in total of the layered composite metal compound. In addition, the dispersant can be produced by blending together with an ethylene copolymer, a layered composite metal compound, and a benzophenone compound, or can be used together when preparing a processed product of a layered composite metal oxide and a benzophenone compound in advance. It is also possible to blend in.

  In general, the solar cell encapsulant of the present invention is preferably produced by a molding method using a T-die extruder, a calendar molding machine or the like. And it can obtain by extruding a solar cell sealing material resin composition by a T-die extruder at the molding temperature which a crosslinking agent does not decompose | disassemble substantially. The thickness of the sealing material is preferably about 0.1 to 1 mm.

  The solar cell encapsulant of the present invention is formed using an ethylene copolymer (A), a layered composite metal compound (B) and / or a fired product thereof (C), and a benzophenone compound (D). It is preferable to become. And with respect to 100 parts by weight of the ethylene copolymer (A), the layered composite metal compound (B) and the fired product (C) thereof are used in an amount of 0.01 to 7 parts by weight and 0.01 to 5 parts by weight, respectively. preferable. Moreover, it is preferable to use 0.5 to 2000 parts by weight of the benzophenone-based compound (D) with respect to 100 parts by weight of the layered composite metal compound (B) or the fired product (C), and 0.5 to 1000 parts by weight is preferable. More preferred. If the amount is less than 0.5 parts by weight, the absolute amount of the benzophenone compound may be insufficient and may not contribute to the conversion efficiency. If the amount exceeds 2000 parts by weight, the amount of the layered composite metal compound is relatively insufficient, resulting in an increase in conversion efficiency. There is a risk of not being able to contribute.

  The solar cell module can be manufactured by fixing solar cell sealing materials on the upper and lower sides of the solar cell element, but is generally manufactured by thermocompression bonding with a vacuum laminator. As such a solar cell module, for example, a superstrate sandwiched between solar cell encapsulants from both sides of the solar cell element such as transparent substrate / solar cell encapsulant / solar cell element / solar cell encapsulant / protective member Structures and solar cell elements formed on the surface of the substrate such as transparent substrate / solar cell element / solar cell encapsulant / protective member are laminated with solar cell encapsulant and protective member. It is done. For the transparent substrate, a heat-strengthened white plate glass or a transparent film is used, and for the sealing material, an ethylene vinyl acetate copolymer having excellent moisture resistance is used. In addition, a sheet having a structure in which aluminum is sandwiched between vinyl fluoride films, a sheet in which aluminum is sandwiched between hydrolysis-resistant polyethylene terephthalate films, and the like are used as protective members that are required to be moistureproof and insulating.

  EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. “Part” means “part by weight” and “%” means “% by weight”.

  Table 1 shows an ethylene polymer, a layered composite metal compound, and a fired product thereof used in Examples and Comparative Examples.

(A) Ethylene polymer (A-1) Ethylene vinyl acetate copolymer (NUC-3195, manufactured by Dow Chemical Company, vinyl acetate content: 24%)
(A-2) Ethylene vinyl acetate copolymer (Ultrasen 751 manufactured by Tosoh Corporation, vinyl acetate content: 28%)
(A-3) Ethylene vinyl acetate copolymer (Evaflex V523, Mitsui / DuPont Polychemical Co., Ltd., vinyl acetate content: 33%)

(B) The chemical composition of the layered composite metal compound (B-1) to (B-10) is shown in Tables 1, 2, and 3.
(C-1): Baked product obtained by heat-treating layered composite metal compound (B-1) at 300 ° C. for 3 hours (C-2): Baked product obtained by heat-treating layered composite metal compound (B-3) at 700 ° C. for 4 hours (C-3): Baked product obtained by heat-treating layered composite metal compound (B-2) at 650 ° C. for 3 hours and half (C-4): Firing obtained by heat-treating layered composite metal compound (B-8) at 500 ° C. for 5 hours Product (C-5): Baked product obtained by heat-treating layered composite metal compound (B-5) at 280 ° C. for 3 and a half hours

The characteristics of (D) benzophenone compounds (D-1) to (D-4) are shown in Table 2.
(D-1) 2-hydroxy-4-n-octoxybenzophenone (D-2) 2-hydroxy-4-methoxybenzophenone (D-3) 2,2′-dihydroxy-4-methoxybenzophenone (D-4) 2-hydroxy-4-dodecyloxybenzophenone

Example 1
85 parts by weight of an ethylene vinyl acetate copolymer (A-1), 10 parts by weight of a fired product of a layered composite metal compound (C-1) and 5 parts by weight of a benzophenone compound (D-1) were mixed with a super mixer (Mitsui Mining Co., Ltd.). The mixture was stirred at a temperature of 20 ° C. for 2 minutes, and then a biaxial extruder (manufactured by Nippon Placon Co., Ltd.) was used to obtain a resin composition for a solar cell encapsulant. Moreover, the stabilizer masterbatch which mix | blended 10 weight part of light stabilizers and 5 weight part of antioxidant with 85 weight part of ethylene vinyl acetate copolymers by the method similar to the resin composition for solar cell sealing materials is obtained. It was. Furthermore, 70 parts by weight of ethylene vinyl acetate copolymer, 10 parts by weight of a crosslinking agent, 10 parts by weight of a crosslinking aid, and 10 parts by weight of a silane coupling agent are impregnated into the ethylene vinyl acetate copolymer while stirring with a super mixer. An agent masterbatch was obtained.
The obtained resin composition for solar cell encapsulant and ethylene vinyl acetate copolymer were used to adjust to the blending amounts shown in Table 3, and the T-die together with the crosslinking agent masterbatch and the stabilizer masterbatch. Extrusion molding was performed at 90 ° C. with an extruder, and solar cell sealing materials 12A, 12B, 16, 18, 21, and 23 (thickness 0.5 mm) used for the test samples of FIGS.
In addition, 5 parts by weight of each of the crosslinking agent masterbatch and the stabilizer masterbatch are blended with respect to a total of 100 parts by weight of the ethylene vinyl acetate copolymer, the layered composite metal compound, and the benzophenone compound as shown in Table 3. did. The types of the crosslinking agent, the crosslinking assistant, the silane coupling agent, the light stabilizer, and the antioxidant are as follows.
Cross-linking agent: 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane cross-linking aid: triallyl isocyanurate silane coupling agent: 3-methacryloxypropyltrimethoxysilane light stabilizer: bis (2 , 2,6,6-tetramethyl-4-piperidyl) sebacate antioxidant: tris (dibutylphenyl) phosphite

(Examples 2-9)
Solar cell encapsulants 12A, 12B used for the test samples of FIGS. 1 to 4 in the same manner as in Example 1 except that the resin composition for solar cell encapsulant was adjusted and blended as shown in Table 3, respectively. 16, 18, 21, and 23 were created.

(Examples 10 to 12)
In the same manner as in Example 1 except that 80 parts by weight of ethylene vinyl acetate copolymer, 10 parts by weight of a layered composite metal compound or a fired product thereof, and 10 parts by weight of a benzophenone-based compound were used. The solar cell sealing material 12A, 12B, 16, 18, 21, 23 (thickness 0.5 mm) used for the test sample of FIGS. 1-4 was prepared by adjusting the resin composition for solar cell sealing material.

(Examples 13 to 16)
While stirring 10 parts by weight of the layered composite metal compound or a fired product thereof with a super mixer, 5 parts by weight of a benzophenone-based compound melted in an oven at 130 ° C. is dropped, and the layered composite metal compound or the fired product thereof is previously added. After the treatment, 85 parts by weight of ethylene vinyl acetate copolymer and 15 parts by weight of the treated product were put into a super mixer (manufactured by Mitsui Mining Co., Ltd.) and stirred at a temperature of 20 ° C. for 2 minutes. Except having obtained the resin composition for solar cell sealing materials by the extruder (made by Nippon Placon Co., Ltd.), the resin composition for solar cell sealing materials was prepared so that it might become the mixing | blending shown in Table 3 like Example 1. FIG. Solar cell sealing materials 12A, 12B, 16, 18, 21, and 23 (thickness 0.5 mm) used for the test samples of FIGS.

(Examples 17 to 22)
An ethylene vinyl acetate copolymer and a layered composite metal compound or a fired product thereof and a benzophenone compound are charged into a supermixer (manufactured by Mitsui Mining Co., Ltd.) so that the blending amounts shown in Table 3 are satisfied. The solar cell seal used for the test samples of FIGS. 1 to 4 is the same as in Example 1 except that the resin composition for solar cell encapsulant is produced by a twin screw extruder (manufactured by Nippon Placon Co., Ltd.). Stop materials 12A, 12B, 16, 18, 21, and 23 (thickness 0.5 mm) were produced.

(Comparative Examples 1-5)
After the ethylene vinyl acetate copolymer and the layered composite metal compound or the fired product thereof are put into a super mixer (made by Mitsui Mining Co., Ltd.) so as to have the blending amounts shown in Table 4, the mixture is stirred at a temperature of 20 ° C. for 2 minutes. Then, a resin composition was prepared by a twin screw extruder (manufactured by Nippon Placon Co., Ltd.) and extruded at 90 ° C. with a T-die extruder together with the same crosslinking agent master batch and stabilizer master batch as in Example 1. Solar cell sealing materials 12A, 12B, 16, 18, 21, and 23 (thickness 0.5 mm) used for the test samples of FIGS.
In addition, 5 parts by weight of each of the crosslinking agent masterbatch and the stabilizer masterbatch are blended with respect to a total of 100 parts by weight of the ethylene vinyl acetate copolymer and the layered composite metal compound, or the fired product, as shown in Table 4. did. The types of the crosslinking agent, crosslinking aid, silane coupling agent, light stabilizer, and antioxidant are the same as in Example 1.

(Comparative Example 6)
An ethylene vinyl acetate copolymer and a benzophenone compound were added to a supermixer (manufactured by Mitsui Mining Co., Ltd.) so as to have the blending amounts shown in Table 4, and stirred at a temperature of 20 ° C. for 2 minutes, and then a twin screw extruder. A resin composition is prepared by (made by Nippon Placon Co., Ltd.), and is extruded and molded at 90 ° C. with a T-die extruder together with the same crosslinking agent masterbatch as in Example 1 and a stabilizer masterbatch. Solar cell encapsulants 12A, 12B, 16, 18, 21, and 23 (thickness 0.5 mm) used for the test samples were prepared.

(Comparative Example 7)
The ethylene vinyl acetate copolymer, the fired product of the layered composite metal compound, and the benzotriazole compound were added to a supermixer (made by Mitsui Mining Co., Ltd.) so that the blending amounts shown in Table 4 were satisfied. After stirring, a resin composition was prepared with a twin screw extruder (manufactured by Nippon Placon Co., Ltd.), and the same crosslinking agent master batch as in Example 1 and a stabilizer master batch were heated to 90 ° C. with a T-die extruder. The solar cell sealing materials 12A, 12B, 16, 18, 21, and 23 (thickness 0.5 mm) used for the test samples of FIGS.
The type and amount of the crosslinking agent, crosslinking aid, silane coupling agent, light stabilizer, and antioxidant in the solar cell encapsulant are the ethylene vinyl acetate copolymer and the layered composite metal compound or the fired product thereof. The same compound and weight as in Example 1 were blended with respect to a total of 100 parts by weight of benzotriazole-based ultraviolet absorber.
Benzotriazole compound: 2- (2-methyl-4-hydroxyphenyl) benzotriazole

(Comparative Example 8)
Except that the benzotriazine compound was used instead of the benzotriazole compound, the resin composition was adjusted so as to have the composition shown in Table 4 in the same manner as in Comparative Example 7, and the sun used for the test samples of FIGS. Battery sealing materials 12A, 12B, 16, 18, 21, and 23 (thickness 0.5 mm) were produced.
The type and amount of the crosslinking agent, crosslinking aid, silane coupling agent, light stabilizer, and antioxidant in the solar cell encapsulant are the ethylene vinyl acetate copolymer and the layered composite metal compound or the fired product thereof. The same compound and weight as in Example 1 were added to 100 parts by weight of the total of benzotriazine-based UV absorber.
Benzotriazine-based compound: 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol

(Comparative Example 9)
5 parts by weight of the same crosslinker masterbatch as in Example 1 and 5 parts by weight of the stabilizer masterbatch were blended with 100 parts by weight of the ethylene vinyl acetate copolymer, and the mixture was heated to 90 ° C. with a T-die extruder. The solar cell sealing materials 12A, 12B, 16, 18, 21, and 23 (thickness 0.5 mm) used for the test samples of FIGS.
In addition, the compound similar to Example 1 was used for the kind of the crosslinking agent in a solar cell sealing material, a crosslinking adjuvant, a silane coupling agent, a light stabilizer, and antioxidant.

The test pieces obtained in the examples were evaluated according to the following criteria, and the evaluation results are shown in Table 5.

[Wavelength conversion effect]
Using the solar cell encapsulant 23 obtained in the examples, the fluorescence intensity when excited at an excitation peak wavelength in the 340 to 420 nm wavelength region was measured by Hitachi F-2500 and evaluated as follows.
A: Very high emission intensity B: High emission intensity B: Low emission intensity X: No emission

[Acid capture effect]
As shown in FIG. 2, using the solar cell encapsulant 16 obtained in the example, a transparent substrate (thickness 3 mm) 15 and a protective member 17 of a polyester film (Toray, Lumirror X-10S, thickness 50 μm) and After being laminated in a laminate, heat-pressed at 150 ° C. for 20 minutes under vacuum by a vacuum laminator to prepare a sample for durability test, and after accelerating the rate of acid generation by an acceleration test, It was measured.

The acceleration test is performed by a pressure cooker test, where the durability test sample is left to stand for 72 hours in an environment of a temperature of 121 ° C., a humidity of 100% RH, and a pressure of 2 kg / cm ² , and then the solar cell encapsulant is transparent The substrate and the polyester film were peeled off, 2 g of the sealing material was immersed in 20 ml of purified water at 25 ° C. for 24 hours, subjected to ultrasonic cleaning for 10 minutes, and then the amount of acetic acid contained in the water extract was quantified by ion chromatography.

[transparency]
As shown in FIG. 3, the solar cell encapsulant 18 obtained in the example was sandwiched between transparent substrates (thickness 3 mm) 19 and 20 to form three layers, and then vacuumed at 150 ° C. under a vacuum laminator. The sample was subjected to thermocompression bonding for 20 minutes to prepare an endurance test sample, and the total light transmittance before and after the acceleration test was measured with a BYK Gardner haze meter.

The acceleration test was carried out by a pressure cooker test, and the sample for durability test was allowed to stand for 120 hours in an environment of a temperature of 121 ° C., a humidity of 100% RH, and a pressure of 2 kg / cm ² .

[Peel strength after time]
The solar cell encapsulant 21 obtained in the example was used to form two layers with a protective member 22 of a hydrolysis-resistant polyethylene terephthalate film (thickness 0.1 mm) as shown in FIG. 4, and then vacuumed by a vacuum laminator The sample for a durability test was produced by thermocompression bonding at 150 ° C. for 20 minutes. And the adhesiveness of the solar cell sealing material and protective member after an endurance test was measured by the peeling test.

  The durability test was performed under the condition that the sample for durability test was allowed to stand for 1000 hours in an environment of a temperature of 85 ° C. and a humidity of 85% RH.

The peel strength between the solar cell encapsulant and the protective member was cut from a sample for durability test into a strip shape having a width of 25 mm and used as a test piece. Then, the test piece was subjected to a 180 ° peel test using a tensile tester at a tensile speed of 50 mm / min.
The peel strength after time indicates the peel strength after the durability test when the peel strength of the sample before the durability test of Comparative Example 9 in which the layered composite metal compound and the benzophenone compound are not blended is 100.

[Conversion efficiency change]
Using the obtained solar cell encapsulants 12A and 12B, a power generation element is sandwiched, and as shown in FIG. 1, three layers of a transparent substrate (thickness 3 mm) 11 and hydrolysis-resistant polyethylene terephthalate / aluminum / hydrolysis-resistant polyethylene terephthalate After being laminated with a protective member 14 (thickness: 1.0 mm), a solar cell module sample was produced by thermocompression bonding at 150 ° C. for 20 minutes under vacuum using a vacuum laminator.
The test was performed with a pressure cooker tester under the condition that the sample was left for 72 hours in an environment of a temperature of 121 ° C., a humidity of 100% RH and a pressure of 2 kg / cm ² .
The conversion efficiency was calculated from the incident light energy, the output at the optimum operating point, and the area of the power generation element.
In the evaluation, a value obtained by subtracting the value of the conversion efficiency of the power generation element alone from the value of the conversion efficiency before the test was defined as the initial conversion efficiency change. And the value which subtracted the value of the conversion efficiency before a sample test from the value of the conversion efficiency after a test was made into the time-dependent conversion efficiency change.
When the initial conversion efficiency is improved, the value of the initial conversion efficiency change becomes positive. The smaller the decrease in the conversion efficiency with time, the smaller the difference from the value of the initial conversion efficiency change.

  From Table 5, the solar cell encapsulant using the composition for solar cell encapsulant of the present invention is based on the results of Examples and Comparative Examples by blending a layered composite metal compound or a fired product thereof with a benzophenone compound. In addition to improving the initial conversion efficiency, it was possible to maintain transparency, maintain adhesiveness with the protective member over time due to a high acid / water scavenging effect, and suppress a decrease in conversion efficiency.

DESCRIPTION OF SYMBOLS 11 Transparent substrate 12A Front surface solar cell sealing material 12B Back surface solar cell sealing material 13 Power generation element 14 Protection member 15 Transparent substrate 16 Sealing material 17 Protection member 18 Sealing material 19 Transparent substrate 20 Transparent substrate 21 Sealing material 22 Protection member 23 Sealing material

Claims (14)

A resin composition for a solar cell encapsulant, comprising an ethylene copolymer (A), a layered composite metal compound (B) and / or a fired product (C) thereof, and a benzophenone compound (D). The layered composite metal compound (B) is represented by the following general formula (1), the resin composition for a solar cell encapsulant according to claim 1.
Mg _1-a · Al _a (OH) ₂ · An ^n- _{a / n} · cH ₂ O General formula (1)
(0.2 ≦ a ≦ 0.35, 0 ≦ c ≦ 1, An: n-valent anion) The layered composite metal compound (B) is represented by the following general formula (2): The resin composition for a solar cell encapsulant according to claim 1.
(M _a Mg _1-a ) _1-b · Al _b (OH) ₂ · An ^n- _{b / n} · cH ₂ O General formula (2)
(M represents a metal selected from Ni, Zn, Cu and Ca, and a, b and c are the formulas 0 ≦ a ≦ 1, 0.2 ≦ b ≦ 0.35, 0 ≦ c ≦ 1, An: n-valent anion) The resin composition for a solar cell sealing material according to any one of claims 1 to 3, wherein the benzophenone-based compound (D) has a melting point of 25 to 120 ° C. The fired product (C) is a fired product obtained by heat-treating the layered composite metal compound (B) at 200 to 800 ° C. The resin composition for a solar cell encapsulant according to any one of claims 1 to 4, object. The layered composite metal compound (B) and the fired product (C) thereof have a BET specific surface area of 1 to 200 m ² / g, and the resin composition for a solar cell encapsulant according to claim 1. The ethylene copolymer (A) comprises an ethylene vinyl acetate copolymer, an ethylene methyl acrylate copolymer, an ethylene ethyl acrylate copolymer, an ethylene methyl methacrylate copolymer, and an ethylene ethyl methacrylate copolymer. It is one or more types of copolymers selected from a group, The resin composition for solar cell sealing materials in any one of Claims 1-6 characterized by the above-mentioned. With respect to 100 parts by weight of the ethylene copolymer (A), the layered composite metal compound (B) and / or the fired product (C) thereof is 0.01 to 15 parts by weight, and the benzophenone compound (C) is 0.01 to The resin composition for a solar cell encapsulant according to any one of claims 1 to 7, wherein 15 parts by weight is used. The resin composition for a solar cell encapsulant according to any one of claims 1 to 8, wherein the benzophenone-based compound (C) has a molar extinction coefficient of 1000 to 15000 (l / mol · cm) at 340 nm. A solar cell encapsulant formed by using an ethylene copolymer (A), a layered composite metal compound (B) and / or a fired product (C) thereof, and a benzophenone compound (C),
The layered composite metal compound (B) is a compound represented by the following general formula (1) or the following general formula (2),
The fired product (C) is a fired product obtained by heat-treating the layered composite metal compound (B) at 200 to 800 ° C.
Mg _1-a · Al _a (OH) ₂ · An ^n- _{a / n} · cH ₂ O General formula (1)
(0.2 ≦ a ≦ 0.35, 0 ≦ c ≦ 1, An: n-valent anion)
(M _a Mg _1-a ) _1-b · Al _b (OH) ₂ · An ^n- _{b / n} · cH ₂ O General formula (2)
(M represents a metal selected from Ni, Zn, Cu and Ca, and a, b and c are the formulas 0 ≦ a ≦ 1, 0.2 ≦ b ≦ 0.35, 0 ≦ c ≦ 1, An: n-valent anion) The solar cell sealing material formed using an ethylene vinyl acetate copolymer and the resin composition for solar cell sealing materials in any one of Claims 1-9. The sun according to claim 10 or 11, wherein 0.5 to 2000 parts by weight of the benzophenone compound (D) is used with respect to 100 parts by weight of the layered composite metal compound (B) and / or the fired product (C) thereof. Battery encapsulant. The solar cell module formed using the resin composition for solar cell sealing materials in any one of Claims 1-9. The solar cell module formed using the solar cell sealing material in any one of Claims 10-12.

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