JP2013008980A - Solar cell sealing material and solar cell module using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell sealing material capable of being crosslinked in a relatively short period of time to exhibit adequate adhesive force at the time of forming a solar cell module by fixing a solar cell element and protection material, and having excellent transparency, flexibility, weather resistance, sheet contamination resistance and the like, and to provide a solar cell module using the same.SOLUTION: A solar cell sealing material including a composition that includes components (A) and (C). The component (A) is an ethylene/α-olefin copolymer polymerized using a metallocene catalyst, in which (a1) a melt flow rate (MFR: 190°C, 21.18 N) is 0.1-50 g/10 min, (a2) a density is 0.860-0.920 g/cm, (a3) the ratio (Mz/Mn) of a z-average molecular weight (Mz) and a number-average molecular weight (Mn) obtained by gel permeation chromatography (GPC) is 8.0 or less, and (a4) a content of α-olefin is 6-40 wt.%. The component (C) is an organic peroxide. The solar cell sealing material has (i) a gel fraction of 80 wt.% or more and (ii) a total light transmittance of 80% or more.

Description

  The present invention relates to a solar cell sealing material and a solar cell module using the same, and more specifically, when a solar cell module is formed by fixing a solar cell element and a protective material, the solar cell module is sufficiently crosslinked in a relatively short time. The present invention relates to a solar cell encapsulant having excellent adhesive strength, excellent transparency, flexibility, weather resistance, sheet contamination resistance, and the like, and a solar cell module using the same.

As global environmental issues such as the reduction of carbon dioxide have been highlighted, solar power generation has come into focus again along with the effective use of hydropower, wind power and geothermal heat.
Photovoltaic power generation generally protects solar cell elements such as silicon, gallium-arsenic, copper-indium-selenium with an upper transparent protective material and a lower substrate protective material, and the solar cell element and the protective material are sealed with resin. This is a solar cell module that is fixed with a material and packaged, and is smaller in size than hydropower, wind power, etc. Research and development aimed at lowering is being promoted. In addition, the government and local governments are gradually promoting the spread of measures by substituting installation costs as a residential solar power generation system introduction promotion project. However, further cost reduction is necessary for further spread, so that not only the development of solar cell elements using new materials to replace conventional silicon and gallium arsenide, but also the manufacturing cost of solar cell modules Efforts to further reduce this are continuing.

  As a condition of the solar cell encapsulant constituting the solar cell module, in order to ensure the incident amount of sunlight so as not to decrease the power generation efficiency of the solar cell, good transparency is required. Moreover, since a solar cell module is usually installed outdoors, it is exposed to sunlight for a long period of time and the temperature rises. Therefore, in order to avoid troubles in which the resin sealing material flows and the module is deformed, it must have heat resistance. Moreover, in order to reduce the material cost of a solar cell element year by year, the thickness has been reduced, and a sealing material with further flexibility is also required.

At present, a sealing material for a solar cell element in a solar cell module uses an ethylene / vinyl acetate copolymer having a high vinyl acetate content as a resin component from the viewpoint of flexibility, transparency, etc. Are used together as a crosslinking agent (see, for example, Patent Document 1).
And in the sealing operation of the solar cell element, after the solar cell element is covered with a resin sealing material, the solar cell element is heated for several minutes to tens of minutes and temporarily bonded, and the organic peroxide is decomposed in the oven. Then, the heat treatment is performed for several minutes to 1 hour (see, for example, Patent Document 2).

  However, in order to reduce the manufacturing cost of the solar cell module, further reduction in the time required for the sealing work is required, and a metallocene catalyst is used instead of the ethylene / vinyl acetate copolymer that is the resin component of the sealing material. It has been proposed to use a polymerized ethylene / α-olefin copolymer (see Patent Document 3).

  Since the solar cell module is exposed to sunlight for a long period of time, the resin component of the encapsulant is blended with a weather resistance stabilizer to provide weather resistance, but bleeds out to the surface when the composition is made into a sheet. However, there are problems such as contamination of the take-up roll and a decrease in transparency.

JP-A-9-116182 JP 2003-204073 A (paragraph

)
JP 2000-91611 A

  An object of the present invention is to form a solar cell module by fixing a solar cell element and a protective material, and have sufficient adhesive strength by crosslinking in a relatively short time, and has transparency, flexibility, weather resistance, An object of the present invention is to provide a solar cell sealing material excellent in sheet contamination and the like and a solar cell module using the same.

  As a result of intensive studies on solar cell encapsulants to solve the above problems, the present inventors selected a specific ethylene / α-olefin copolymer polymerized using a metallocene catalyst as the resin component, and By using a composition in which a weathering stabilizer having a specific structure and a crosslinking agent are blended, the inventors have obtained knowledge that the object of the invention can be achieved, and have completed the present invention.

That is, according to 1st invention of this invention, it consists of a composition containing the following component (A) and a component (C), and the solar cell sealing material which has the following characteristics (i)-(ii). Provided.
Component (A): an ethylene / α-olefin copolymer polymerized using a metallocene catalyst and having the following characteristics (a1) to (a4) (a1) melt flow rate (MFR: 190 ° C., 21.18 N load) ) 0.1-50 g / 10 min (a2) Density 0.860-0.920 g / cm ³
(A3) The ratio (Mz / Mn) of the Z average molecular weight (Mz) and the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 8.0 or less. (A4) The content of α-olefin is 6-40% by weight
Component (C): Organic peroxide (i) Gel fraction is 80 wt% or more (ii) Total light transmittance 80% or more

  According to the second invention of the present invention, in the first invention, the content of the component (C) is 0.2 to 5 parts by weight with respect to 100 parts by weight of the component (A). A featured solar cell encapsulant is provided.

  According to the third invention of the present invention, there is provided a solar cell encapsulant characterized in that, in the first or second invention, the component (A) is a copolymer of ethylene and 1-hexene. Is done.

  According to the fourth invention of the present invention, in any one of the first to third inventions, the component (A) is an ethylene / hexene / propylene terpolymer. An encapsulant is provided.

  Furthermore, according to 5th invention of this invention, the solar cell module obtained using the solar cell sealing material of the invention in any one of 1-4 is provided.

The solar cell encapsulant of the present invention bleeds out to the surface when the composition is made into a sheet and does not contaminate the take-up roll, and the resin composition can be formed in a relatively short time when modularized. Since it crosslinks and has sufficient adhesive force, formation of a solar cell module is easy, and the manufacturing cost of a solar cell module can be reduced.
Moreover, the obtained solar cell module becomes excellent in transparency, flexibility, weather resistance, etc., and it can be expected to maintain stable conversion efficiency for a long period of time.

1. Solar cell encapsulant (1) Component (A)
The component (A) used for the solar cell encapsulant of the present invention (hereinafter also simply referred to as encapsulant) is polymerized using a metallocene catalyst and has the following characteristics (a1) to (a4): ethylene / α -Olefin copolymer.

(A1) Melt flow rate (MFR: 190 ° C., 21.18N load) is 0.1 to 50 g / 10 minutes (a2) Density is 0.860 to 0.920 g / cm ³
(A3) The ratio (Mz / Mn) of the Z average molecular weight (Mz) and the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 8.0 or less. (A4) The content of α-olefin is 6-40% by weight

(I) Monomer structure of component (A) The ethylene / α-olefin copolymer used in the present invention is a random copolymer of ethylene and α-olefin, the main component of which is a structural unit derived from ethylene. .

  The α-olefin used as a comonomer is preferably an α-olefin having 3 to 12 carbon atoms. Specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4,4-dimethylpentene- 1 etc. can be mentioned. Specific examples of such ethylene / α-olefin copolymers include ethylene / propylene copolymers, ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, ethylene / 1-octene copolymers, ethylene -4-methyl-pentene-1 copolymer etc. are mentioned. Moreover, 1 type, or 2 or more types of combination may be sufficient as an alpha olefin. When combining two kinds of α-olefins into a terpolymer, ethylene / propylene / hexcenter polymer, ethylene / butene / hexcenter polymer, ethylene / propylene / octene terpolymer, ethylene / butene / octene terpolymer, etc. may be mentioned. It is done.

  The amount of ethylene units in the ethylene / α-olefin copolymer will be described later as the characteristic (a4).

(Ii) Polymerization catalyst and polymerization method of component (A) The ethylene / α-olefin copolymer used in the present invention can be produced using a Ziegler catalyst or a metallocene catalyst, preferably a metallocene catalyst. Examples of the production method include a high-pressure ion polymerization method, a gas phase method, a solution method, and a slurry method.

  The metallocene catalyst is not particularly limited, but the same catalyst as described in JP-A-7-508545, for example, complex dimethylsilylene bis (4,5,6,7-tetrahydroindene A catalyst solution or the like obtained by adding equimolar amount of tripentafluorophenylboron to 2.0 mmol of (nyl) hafnium dimethyl and diluting to 10 liters with toluene can be preferably used. Examples of commercially available products include Harmolex series, Kernel series manufactured by Nippon Polyethylene, Evolue series manufactured by Prime Polymer, Excellen GMH series, Excellen FX series manufactured by Sumitomo Chemical.

(Iii) Characteristics of component (A) (a1) Melt flow rate The ethylene / α-olefin copolymer used in the present invention has an MFR of 0.1 to 50 g / 10 min, preferably 0.5 to 40 g / 10 minutes, more preferably 1.0 to 35 g / 10 minutes. When the MFR of the ethylene / α-olefin copolymer is less than 0.1 g / 10 minutes, the resin pressure is high and the moldability is poor. When the MFR exceeds 50 g / 10 minutes, the resin drips during molding and cannot be processed. There's a problem.

In order to adjust the MFR of the polymer, for example, a method of appropriately adjusting the polymerization temperature, the amount of catalyst, the supply amount of hydrogen as a molecular weight regulator and the like is employed.
The MFR of the ethylene / α-olefin copolymer is measured according to JIS-K6922-2: 1997 appendix (190 ° C., 21.18 N load).

(A2) Density The ethylene / α-olefin copolymer used in the present invention has a density of 0.860 to 0.920 g / cm ³ , preferably 0.870 to 0.915 g / cm ³ , and more preferably 0.875. ˜0.910 g / cm ³ . If the density of the ethylene / α-olefin copolymer is less than 0.860 g / cm ³ , the processed sheet is blocked, which is not preferable.

In order to adjust the density of the polymer, for example, a method of appropriately adjusting the α-olefin content, the polymerization temperature, the catalyst amount and the like is employed.
The density of the ethylene / α-olefin copolymer is measured according to JIS-K6922-2: 1997 appendix (in the case of low density polyethylene) (23 ° C.).

(A3) Ratio (Mz / Mn) of Z average molecular weight (Mz) to number average molecular weight (Mn)
The ethylene / α-olefin copolymer used in the present invention has a ratio (Mz / Mn) of Z average molecular weight (Mz) to number average molecular weight (Mn) determined by gel permeation chromatography (GPC) of 8.0. Or less, preferably 5.0 or less. When (Mz / Mn) exceeds 8, transparency deteriorates. Examples of a method for adjusting (Mz / Mn) to a predetermined range include a method for selecting an appropriate metallocene catalyst.

In addition, the measurement of (Mz / Mn) is performed by gel permeation chromatography (GPC), and the measurement conditions are as follows.
Apparatus: Waters GPC 150C type detector: MIRAN 1A infrared spectrophotometer (measurement wavelength: 3.42 μm)
Column: Showa Denko 3 AD806M / S (column calibration is Tosoh monodispersed polystyrene (0.5 mg / ml solution of each of A500, A2500, F1, F2, F4, F10, F20, F40, and F288) The logarithmic value of the elution volume and molecular weight was approximated by a quadratic equation, and the molecular weight of the sample was converted to polyethylene using the viscosity equation of polystyrene and polyethylene, where the coefficient of the viscosity equation of polystyrene is α = 0.723, log K = -3.967, polyethylene is α = 0.733, log K = -3.407.)
Measurement temperature: 140 ° C
Concentration: 20 mg / 10 mL
Injection volume: 0.2ml
Solvent: Orthodichlorobenzene Flow rate: 1.0 ml / min

  Since Mz contributes greatly to the average molecular weight of the high molecular weight component, (Mz / Mn) is easier to confirm the presence of the high molecular weight component than (Mw / Mn). The high molecular weight component is a factor that affects the transparency, and when the high molecular weight component is large, the transparency is deteriorated. Moreover, the tendency for a crosslinking efficiency to deteriorate is seen. Therefore, a smaller Mz / Mn is preferable.

(A4) α-Olefin Content The ethylene / α-olefin copolymer used in the present invention has an α-olefin content of 5 to 40% by weight, preferably 10 to 35% by weight, and more preferably. 15 to 30% by weight. When the α-olefin content is low, the impact strength and flexibility of the sheet cannot be obtained, and when it is too high, the heat resistance is impaired.

Here, the content of α-olefin is a value measured by ¹³ C-NMR method under the following conditions.
Device: JEOL-GSX270 manufactured by JEOL
Concentration: 300 mg / 2 mL
Solvent: Orthodichlorobenzene

(2) Component (B)
In the present invention, a copolymer of ethylene and a cyclic aminovinyl compound represented by the following formula (I) can be used as the component (B).

In formula (I), R ¹ and R ² represent a hydrogen atom or a methyl group, and R ³ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Typical examples of the cyclic aminovinyl compound represented by the general formula (I) are as follows.

1) 4-acryloyloxy-2,2,6,6-tetramethylpiperidine 2) 4-acryloyloxy-1,2,2,6,6-pentamethylpiperidine 3) 4-acryloyloxy-1-ethyl-2 2,6,6-tetramethylpiperidine 4) 4-acryloyloxy-1-propyl-2,2,6,6-tetramethylpiperidine 5) 4-acryloyloxy-1-butyl-2,2,6,6 -Tetramethylpiperidine 6) 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine 7) 4-methacryloyloxy-1,2,2,6,6-pentamethylperidine 8) 4-methacryloyloxy- 1-ethyl-2,2,6,6-tetramethylpiperidine 9) 4-methacryloyloxy-1-butyl-2,2,6,6-tetramethylpiperidine Down 10) 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine 11) 4-crotonoyloxy-oxy-1-propyl-2,2,6,6-tetramethylpiperidine

The content of the cyclic aminovinyl compound in the copolymer of ethylene and the cyclic aminovinyl compound is preferably 0.1 to 10% by weight, preferably 0.5 to the total amount of ethylene and the cyclic aminovinyl compound. It is 8% by weight, more preferably 1 to 6% by weight. The MFR (190 ° C., 21.18N) of the copolymer is 0.1 to 200 g / 10 minutes, preferably 0.5 to 100 g / 10 minutes, particularly preferably 0.7 to 50 g / 10 minutes. . The copolymer can be produced, for example, by a high-pressure radical polymerization method described in JP-A-4-80215. Specifically, ethylene and a cyclic aminovinyl compound are mixed in 1,000 to 5,000 kg. Radical polymerization at a pressure of / cm ² and a temperature of 100 to 400 ° C.

The number average molecular weight determined by GPC of the copolymer is preferably 1000 or more, more preferably 5000 or more, and still more preferably 10,000 or more. The GPC measurement is the same as described above.
Moreover, you may substitute a part of component (B) with the other hindered amine compound whose molecular weight is 1000 or more. In that case, the functional group (hindered amine) content effective for weather resistance is preferably 0.05% by weight or less based on the total amount of the component (A) and the component (B).

(3) Mixing ratio of component (A) and component (B) When using component (B), the mixing ratio of component (A) and component (B) (copolymer of ethylene and cyclic aminovinyl compound) is: The cyclic aminovinyl compound unit in the copolymer is 0.05 to 5% by weight, preferably 0.1 to 3% by weight, particularly preferably 0.1%, based on the total amount of component (A) and component (B). ˜1% by weight. If the blending ratio of the cyclic aminovinyl compound unit in the resin composition is less than the above range, the weather resistance may be insufficient and the strength may not be obtained, and if it exceeds the above range, the transparency of the sheet deteriorates. In some cases, it may become impractical.

(4) Component (C)
Component (C) used in the composition of the present invention is an organic peroxide (crosslinking agent) and is mainly used for crosslinking component (A).

  As the crosslinking agent, an organic peroxide having a decomposition temperature (temperature at which the half-life is 1 hour) is 70 to 180 ° C., particularly 90 to 160 ° C. can be used. Examples of such organic peroxides include tertiary butyl peroxyisopropyl carbonate, tertiary butyl peroxyacetate, tertiary butyl peroxybenzoate, dicumyl peroxide, 2,5-dimethyl-2,5-bis ( Tert-butylperoxy) hexane, di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexyne-3, 1,1-bis (tert-butylperoxy)- 3,3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, methyl ethyl ketone peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, tert-butyl hydroperoxide, p-menthane hydroperoxide, benzoyl peroxide, p-chlorobe Benzoyl peroxide, tert-butylperoxy isobutyrate, hydroxyheptyl peroxide, and di cyclohexanone peroxide.

(5) Blending ratio of component (C) The blending ratio of component (C) is 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, when component (A) is 100 parts by weight. Particularly preferred is 1 to 2 parts by weight. When the blending ratio of the component (C) is less than the above range, crosslinking is not performed or it takes time for crosslinking. Moreover, when larger than the said range, it cannot fully mix at the time of a fusion | melting.

(6) Crosslinking aid In addition to the component (C), a crosslinking aid can be blended. The crosslinking aid is effective in promoting the crosslinking reaction and increasing the degree of crosslinking of the ethylene / α-olefin copolymer. Specific examples thereof include polyaryl compounds and poly (meth) acryloxy compounds. Saturated compounds can be exemplified.

  More specifically, polyallyl compounds such as triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl fumarate, diallyl maleate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, etc. Examples include poly (meth) acryloxy compounds and divinylbenzene. A crosslinking adjuvant can be mix | blended in the ratio of about 0.5-5 weight part with respect to 100 weight part of component (A).

(7) Other additive components In the composition of this invention, another additional arbitrary component can be mix | blended in the range which does not impair the effect of this invention remarkably. As such optional components, antioxidants, crystal nucleating agents, clearing agents, lubricants, colorants, dispersants, fillers, fluorescent whitening agents, UV absorbers used in ordinary polyolefin resin materials, A light stabilizer etc. can be mentioned.

Further, in order to give flexibility in a range not impairing the effects of the present invention, a crystalline ethylene / α-olefin copolymer polymerized with a Ziegler-based or metallocene-based catalyst and / or an ethylene / EBR / EPR / It is also possible to blend 3 to 75 parts by weight of a rubber compound such as an α-olefin elastomer or SEBS, a styrene elastomer such as a hydrogenated styrene block copolymer.
Furthermore, in order to give melt tension, 3-75 weight part of high pressure process low density polyethylene can also be mix | blended.

(8) Characteristics of Solar Cell Encapsulant The solar cell encapsulant of the present invention has the following characteristics (i) to (ii).

(I) Gel fraction The gel fraction is 80 wt% or more, preferably 85 wt% or more, and more preferably 93 wt% or more.
The gel fraction was determined by using a T-die molding machine (die width: 500 mmφ, die lip: 3 mm, die temperature: 100 ° C.), and forming a sheet having a thickness of 2 mm on a hot press machine at 180 ° C. for 10 minutes. After storage, about 1 g is cut out and weighed accurately, immersed in 100 cc of xylene, treated at 110 ° C. for 24 hours, the residue after filtration is dried and precisely weighed, and the gel fraction is calculated by dividing the weight before treatment. Heat resistance improves more that a gel fraction is 80 wt% or more.

(Ii) Total light transmittance The light transmittance is 80 when the sheet prepared as described above is stored in a hot press machine at 180 ° C. for 10 minutes and measured according to JIS-K7105-1981. % Or more, preferably 85% or more, and more preferably 91% or more. When the light transmittance is 80% or more, when a solar cell module is obtained, it is preferable because solar rays sufficiently reach the solar cells.

The solar cell encapsulant of the present invention preferably further has the following properties (iii) to (iv).
(Iii) Adhesive strength with glass Adhesive strength cannot be removed when peeled by hand after placing the sheet prepared as described above on a glass substrate under conditions of 180 ° C. for 10 minutes. It is preferable.

(Iv) Tensile modulus (MD)
The tensile modulus of elasticity of the sheet produced as described above is measured in accordance with ISO 1184-1983, and the tensile modulus of elasticity (MPa) in the MD direction (sheet take-up direction) is measured. The smaller this value is, the better the flexibility is, and it is 100 MPa or less, preferably 50 MPa or less, more preferably 30 MPa or less.

2. Production of Solar Cell Encapsulant The solar cell encapsulant of the present invention can be produced by a known sheet molding method using a T-die extruder, a calendar molding machine or the like.

  For example, a component (C) is added to an ethylene / α-olefin copolymer, and if necessary, a composition obtained by dry blending components (B), additives such as a crosslinking aid and an antioxidant in advance is subjected to T-die extrusion. It can be formed by feeding from a hopper of the machine and extruding it into a sheet. Of course, in these dry blends, some or all of the additives can be used in the form of a masterbatch. Also, in T-die extrusion and calendering, it is obtained by melt-mixing some or all of the additive to the ethylene / α-olefin copolymer in advance using a single screw extruder, twin screw extruder, Banbury mixer, kneader, etc. Resin compositions can also be used.

  Thereby, the solar cell sealing material of this invention is shape | molded by the sheet form of thickness about 0.1-3 mm. If the thickness is less than 0.1 mm, the strength is low, and the adhesion is insufficient. If the thickness is more than 3 mm, the transparency may be lowered, which may be a problem. A preferable thickness is 0.1 to 2 mm.

3. Manufacture of solar cell module The solar cell module of the present invention can be manufactured by fixing the solar cell element with upper and lower protective materials using the solar cell sealing material of the present invention. Examples of such solar cell modules include various types.

  For example, an upper transparent protective material / encapsulating material / solar cell element / encapsulating material / lower protective material that is sandwiched between both sides of the solar cell element by an encapsulating material, on the inner peripheral surface of the lower substrate protective material A structure in which a sealing material and an upper transparent protective material are formed on the formed solar cell element, a solar cell element formed on the inner peripheral surface of the upper transparent protective material, for example, a fluororesin-based transparent protective material In addition, a structure in which an encapsulant and a lower protective material are formed on an amorphous solar cell element formed by sputtering or the like can be used.

  The solar cell element is not particularly limited, and is based on silicon such as single crystal silicon, polycrystalline silicon, amorphous silicon, III-V group or II-VI group such as gallium-arsenic, copper-indium-selenium, cadmium-tellurium. Various solar cell elements such as compound semiconductors can be used.

  Examples of the upper protective material constituting the solar cell module include glass, acrylic resin, polycarbonate, polyester, and fluorine-containing resin. The lower protective material is a single or multilayer sheet such as metal or various thermoplastic resin films, for example, metals such as tin, aluminum, and stainless steel, inorganic materials such as glass, polyester, inorganic vapor deposition polyester, fluorine-containing resin And a single-layer or multilayer protective material such as polyolefin. Such an upper and / or lower protective material can be subjected to a primer treatment in order to enhance the adhesion to the sealing material.

  In the sealing operation of the solar cell element, after covering the solar cell element with the sealing material of the present invention, the solar cell element is temporarily bonded by heating to a temperature at which the organic peroxide is not decomposed for several minutes to 10 minutes, In addition, there is a method in which the organic peroxide is decomposed in the oven at a high temperature of about 150 to 200 ° C. for 5 to 30 minutes to be bonded.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The evaluation methods and resins used in the examples and comparative examples are as follows.

1. Evaluation method of resin physical properties (1) Melt flow rate (MFR): MFR of ethylene / α-olefin copolymer is measured according to JIS-K6922-2: 1997 appendix (190 ° C., 21.18 N load). did.
(2) Density: As described above, the density of the ethylene / α-olefin copolymer was measured according to JIS-K6922-2: 1997 appendix (23 ° C., in the case of low density polyethylene).
(3) Mz / Mn: Measured by GPC as described above.

2. Sheet production method Using a T-die molding machine (die width; 500 mmφ, die lip; 3 mm, die temperature; 100 ° C.), a sheet having a thickness of 2 mm was formed.

3. Sheet Evaluation Method (1) Total light transmittance, HAZE
The produced sheet was stored in a hot press machine at 180 ° C. for 10 minutes and measured according to JIS-K7105-1981.
(2) Tensile modulus (MD)
About the produced sheet | seat, based on ISO1184-1983, the tensile elasticity modulus of MD direction (sheet taking-up direction) was measured. It shows that it is excellent in the softness, so that this value is small.
(3) Gel fraction After the produced sheet was stored in a hot press for 10 minutes at 180 ° C., about 1 g was cut out and weighed accurately. It was immersed in 100 cc of xylene and treated at 110 ° C. for 24 hours. After filtration, the residue was dried and precisely weighed. The gel fraction was calculated by dividing the weight before treatment.
(4) Adhesive strength with glass Each sheet was stored on a glass substrate at 180 ° C. for 10 minutes. Then, it peeled off by hand. As a result, what was peeled off was marked with x, and what was not peeled off was marked with ○.
(5) Contamination resistance After the film was produced by a T-die molding machine for 10 minutes, the state of dirt on the take-up roll was observed and evaluated according to the following criteria.
○: Roll dirt is not recognized.
X: Roll contamination is remarkable.

4). Used raw material (1) Component (A): Ethylene / α-olefin copolymer (PE-1) to (PE-3) polymerized in Production Examples 1 to 3 using the catalyst prepared in the following Catalyst Production Example Using. The physical properties are shown in Table 1.

<Examples of catalyst production>
(I) Preparation of catalyst A catalyst for producing a copolymer of ethylene and hexene-1 was prepared by the method described in JP-T-7-508545. That is, to the complex dimethylsilylene bis (4,5,6,7-tetrahydroindenyl) hafnium dimethyl 2.0 mmol, tripentafluorophenyl boron is added in an equimolar amount to the complex, and diluted to 10 liters with toluene. A catalyst solution was prepared.

(Ii) Polymerization <Production Example 1>
A stirred autoclave type continuous reactor having an internal volume of 1.5 liters was maintained at a pressure of 130 MPa, and a mixture of ethylene and 1-hexene was mixed at 40 kg / hour so that the composition of 1-hexene was 75% by weight. The raw material gas was continuously supplied at a rate of. The catalyst solution was continuously supplied, and the supply amount was adjusted so that the polymerization temperature was maintained at 149 ° C. The polymer production per hour was about 2.6 kg. After completion of the reaction, an ethylene / 1-hexene copolymer (PE-) having 1-hexene content = 24 wt%, MFR = 30 g / 10 min, density = 0.880 g / cm ³ , and Mz / Mn = 3.7 1) was obtained. The characteristics of this ethylene / 1-hexene copolymer (PE-1) are shown in Table 1.

<Production Example 2>
Polymerization was carried out by the same production method as in Production Example 1 except that the composition of 1-hexene at the time of polymerization was 77% by weight and the polymerization temperature was changed to 124 ° C. The polymer production per hour was about 2.6 kg. After completion of the reaction, 1 / 1-hexene content = 29.5 wt%, MFR = 5.0 g / 10 min, density = 0.870 g / cm ³ , and ethylene / 1-hexene copolymer weight with Mz / Mn = 3.5 A coalescence (PE-2) was obtained. The characteristics of this ethylene / 1-hexene copolymer (PE-2) are shown in Table 1.

<Production Example 3>
Polymerization was carried out in the same manner as in Production Example 1 except that the composition of 1-hexene at the time of polymerization was changed to 33% by weight and the polymerization temperature was changed to 178 ° C. The polymer production per hour was about 2.6 kg. After completion of the reaction, an ethylene / 1-hexene copolymer (PE-) having 1-hexene content = 5 wt%, MFR = 5 g / 10 min, density = 0.925 g / cm ³ , and Mz / Mn = 3.5 3) was obtained. The characteristics of this ethylene / 1-hexene copolymer (PE-3) are shown in Table 1.

(2) Component (B): Copolymer of ethylene and the cyclic aminovinyl compound represented by the above formula (I) The following copolymer was used as the component (B).
B-1: manufactured by Nippon Polyethylene Co., Ltd., XJ100H (ethylene-4-acryloyloxy-2,2,6,6-tetramethylpiperidine copolymer, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine (Content 5.2% by weight, MFR 3 g / 10 min)
B-2: Tinuvin 770 (bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate) manufactured by Ciba Specialty Chemicals

(3) Component (C): Organic peroxide The following organic peroxide (crosslinking agent) was used as the component (C).
C-1: Kayahexa AD (2,5-dimethyl-2,5-di (t-butylperoxy) hexane) manufactured by Arkema Yoshitomi

(4) Ethylene vinyl acetate copolymer The ethylene vinyl acetate copolymer (EVA-1, 2) shown below was used.
EVA-1: manufactured by Nippon Polyethylene Co., Ltd., LV670 (MFR 15 g / 10 min, vinyl acetate content 28 wt%)
EVA-2: manufactured by Nippon Polyethylene Co., Ltd., LV780 (MFR 30 g / 10 min, vinyl acetate content 33 wt%)

Example 1
As component (A), PE-1 was mixed at 95% by weight, component (B) was mixed at 5% by weight of B-1, and component C- was added to the total amount of component (A) and component (B). 0.5 parts of 1 was blended, and the composition was melt-kneaded under the following conditions to form pellets. In addition, the compounding ratio of a component (B-1) is equivalent to 0.26 weight% with respect to the resin composition whole quantity of a component (A) and a component (B) in the cyclic amino vinyl compound unit in this copolymer. .
Extruder: TEX35 twin screw extruder Resin temperature: 130 ° C
Using the pellet, a sheet having a thickness of 2 mm was produced with a T-die machine as described above. Thereafter, the contamination resistance, total light transmittance, HAZE, tensile elastic modulus (MD), gel fraction, and adhesive strength with glass were measured and evaluated. The evaluation results are shown in Table 2.

(Example 2)
A pellet having a thickness of 2 mm was prepared using a T-die machine using a pellet prepared in the same manner as in Example 1 except that PE-2 was used instead of PE-1. Thereafter, the contamination resistance, total light transmittance, HAZE, tensile elastic modulus (MD), gel fraction, and adhesive strength with glass were measured and evaluated. Evaluation was performed. The results are shown in Table 2.

(Example 3)
Except that the content of C-1 was 1 part by weight, pellets were produced in the same manner as in Example 1, and a sheet having a thickness of 2 mm was produced using a T-die machine. Thereafter, the contamination resistance, total light transmittance, HAZE, tensile elastic modulus (MD), gel fraction, and adhesive strength with glass were measured and evaluated. Evaluation was performed. The results are shown in Table 2.

Example 4
Except that the content of C-1 was 1 part by weight, a pellet was prepared in the same manner as in Example 2, and a sheet having a thickness of 2 mm was prepared using a T-die machine. Thereafter, the contamination resistance, total light transmittance, HAZE, tensile elastic modulus (MD), gel fraction, and adhesive strength with glass were measured and evaluated. Evaluation was performed. The results are shown in Table 2.

(Example 5)
As component (A), PE-1 was mixed with 99.74% by weight, and component (B) was mixed with B-2 at 0.26% by weight. To this, the total amount of component (A) and component (B), 0.5 parts of component C-1 was mix | blended, the pellet was produced for this composition like Example 1, and the sheet | seat of thickness 2mm was produced using this with the T-die machine.
Thereafter, the contamination resistance, total light transmittance, HAZE, tensile elastic modulus (MD), gel fraction, and adhesive strength with glass were measured and evaluated. The results are shown in Table 2.
Although this roll contaminates the roll during molding, there is no problem in practical use.

(Comparative Example 1)
A pellet having a thickness of 2 mm was produced using a T-die machine using a pellet prepared in the same manner as in Example 1 except that PE-3 was used instead of PE-1. Thereafter, the contamination resistance, total light transmittance, HAZE, tensile elastic modulus (MD), gel fraction, and adhesive strength with glass were measured and evaluated. Evaluation was performed. The results are shown in Table 2.
This is not preferred because it lacks flexibility and has a poor total light transmittance.

(Comparative Example 2)
A pellet having a thickness of 2 mm was produced using a T-die machine using a pellet prepared in the same manner as in Example 1 except that EVA-1 was used instead of PE-1. Thereafter, the contamination resistance, total light transmittance, HAZE, tensile elastic modulus (MD), gel fraction, and adhesive strength with glass were measured and evaluated. Evaluation was performed. The results are shown in Table 2.
This is not preferred because it has a low gel fraction and lacks adhesion to glass.

(Comparative Example 3)
Instead of PE-1, except that EVA-2 was used, a pellet was prepared in the same manner as in Example 1, and a sheet having a thickness of 2 mm was prepared using a T-die machine. Thereafter, the contamination resistance, total light transmittance, HAZE, tensile elastic modulus (MD), gel fraction, and adhesive strength with glass were measured and evaluated. Evaluation was performed. The results are shown in Table 2.
This is not preferred because it has a low gel fraction and lacks adhesion to glass.

(Comparative Example 4)
Except not using C-1, the pellet was produced similarly to Example 1, and the sheet | seat of thickness 2mm was produced with the T-die machine using this. Thereafter, the contamination resistance, total light transmittance, HAZE, tensile elastic modulus (MD), gel fraction, and adhesive strength with glass were measured and evaluated. Evaluation was performed. The results are shown in Table 2.
This is not preferred because it has a low gel fraction and lacks adhesion to glass.

Claims (5)

The solar cell sealing material which consists of a composition containing the following component (A) and a component (C), and has the following characteristics (i)-(ii).
Component (A): an ethylene / α-olefin copolymer polymerized using a metallocene catalyst and having the following characteristics (a1) to (a4) (a1) melt flow rate (MFR: 190 ° C., 21.18 N load) ) 0.1-50 g / 10 min (a2) Density 0.860-0.920 g / cm ³
(A3) The ratio (Mz / Mn) of the Z average molecular weight (Mz) and the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 8.0 or less. (A4) The content of α-olefin is 6-40% by weight
Component (C): Organic peroxide (i) Gel fraction is 80 wt% or more (ii) Total light transmittance 80% or more   Content of a component (C) is 0.2-5 weight part with respect to 100 weight part of components (A), The solar cell sealing material of Claim 1 or 2 characterized by the above-mentioned.   The solar cell encapsulant according to claim 1 or 2, wherein the component (A) is a copolymer of ethylene and 1-hexene.   The solar cell encapsulant according to any one of claims 1 to 3, wherein the component (A) is a terpolymer of ethylene, hexene and propylene.   The solar cell module obtained using the solar cell sealing material in any one of Claims 1-4.