JP2012214555A - Resin composition, sheet formed material and solar cell sealing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive solar cell sealing material that has excellent flexibility (embedding property of level difference), heat resistance, adhesiveness, electric insulation properties, moisture permeability, moldability and process handleability even without a crosslinking treatment in a solar cell sealing material comprising an ethylene-based resin composition.SOLUTION: The resin composition comprises a component (A) being an ethylene-based polymer satisfying specific requirements or its modified substance with an ethylenic unsaturated silane compound (C) and a component (B) being an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10-47 mass% or its modified substance with the ethylenic unsaturated silane compound (C). Either or both of the component (A) and the component (B) are modified substances with the ethylenic unsaturated silane compound (C). The content of the component (B) to the total amount of the component (A) and the component (B) is 5-50 mass%.

Description

  The present invention relates to a resin composition, and further relates to a sheet molded article and a solar cell encapsulant containing the same.

  As global environmental and energy problems become more serious, solar energy is attracting attention as an energy source that is clean and does not have the risk of exhaustion. It is attracting attention as a supply method.

  When a solar cell is used outdoors such as a roof portion of a building, it is generally used in the form of a solar cell module. The solar cell module has weather resistance and is suitable for outdoor use. The solar cell module is roughly divided into two types: a crystalline solar cell module and a thin film solar cell module.

  The crystalline solar cell module includes a crystalline solar cell formed of polycrystalline silicon, single crystal silicon, or the like. Crystalline solar cell module includes solar cell module protective sheet (surface protective member) / solar cell encapsulating sheet / crystalline solar cell / solar cell encapsulating sheet / solar cell module protective sheet (back surface protecting member). The laminates laminated in this order can be manufactured by vacuum suction and thermocompression laminating.

  The thin film type solar cell module includes a thin film type solar cell in which a thin film of several μm such as amorphous silicon or a compound semiconductor is formed on a substrate such as glass. A thin film type solar cell module is manufactured by vacuum-sucking and laminating a laminated body in the order of a thin film type solar cell / a solar cell encapsulating sheet / a solar cell module protective sheet (back surface protection member). Can be done.

  Conventionally, an ethylene-vinyl acetate copolymer (EVA) has been widely used as a material (solar cell encapsulant) constituting a solar cell encapsulant from the viewpoint of requiring transparency, flexibility and the like. (For example, see Patent Document 1). When an ethylene-vinyl acetate copolymer is used as a solar cell encapsulant, it is common to perform a crosslinking treatment in order to impart sufficient heat resistance. However, since the crosslinking process requires a relatively long time of about 0.2 to 2 hours, it has been a cause of lowering the production speed and production efficiency of the solar cell module.

  In recent years, cost reduction of solar cell modules is strongly desired, and studies such as simplification of the process and reduction of the number of parts are being conducted. The edge of the module is generally fixed with a metal (aluminum) frame, but the cost of the metal frame occupies a high specific gravity among the components. Therefore, a so-called laminated glass type module that uses glass as a back side protection member and does not have a frame is being widely used. In particular, the tendency is remarkable in the thin film solar cell module.

  Polyvinyl butyral (PVB) is widely used in addition to EVA as a solar cell encapsulant for laminated glass type thin-film solar cell modules, but the process handling of PVB is very poor due to tack and the material cost is also low. Alternative materials have been desired due to their high cost.

  As an alternative to EVA and PVB, many thermoplastic polyolefin (polyethylene) -based sealing materials have been proposed as inexpensive sealing materials that have excellent handling properties and do not require a crosslinking step. (See Patent Documents 2 to 4)

JP-A-8-283696 JP 2005-019995 A Japanese Patent Laid-Open No. 2007-150069 Japanese Patent Laid-Open No. 2002-235048

  As described above, Patent Documents 2 to 4 propose a solar cell encapsulant containing a main component containing an ethylene / α-olefin copolymer, but preferable characteristics (heat resistance) as a solar cell encapsulant. No specific guidelines for physical properties of the ethylene / α-olefin copolymer for obtaining flexibility, process stability resistance, etc. are disclosed.

  Patent Document 3 also proposes a solar cell encapsulant containing a metallocene-based linear low-density polyethylene, but about the physical properties of polyethylene for obtaining preferable characteristics as a solar cell encapsulant, other than the density It does not disclose any specific guidelines. Further, the solar cell encapsulant of Patent Document 3 may have low heat resistance and moisture resistance.

  In the case of a laminated glass type module, when a step is embedded (filled with a sealing material) in a step portion due to the thickness of the wiring material of the extraction electrode, the glass follows its shape and deforms not a little. The deformed glass is subjected to a force to return to the original (flat) shape, and residual stress is generated. Since this residual stress is strongly applied to the sealing material and its adhesion interface, peeling may occur in a region where the residual stress cannot be tolerated during or after lamination.

Therefore, the sealing material is required to have flexibility (rubber elasticity) in addition to sufficient adhesive force.
However, generally, when the flexibility is increased, the melting point (softening point) is lowered, so it has been difficult to achieve both flexibility and heat resistance with thermoplastic materials.

  Although investigations focusing on durability and adhesive strength have been conducted on thermoplastic polyolefin (polyethylene) -based sealing materials, studies to achieve both embedding (flexibility) and heat resistance as described above It wasn't done enough. In Patent Document 4, the shear modulus at 80 ° C. is specified, but attention is paid to adhesiveness and heat resistance, and the embedding property is not described.

  In view of the above background, the object of the present invention is to provide a solar cell encapsulant containing an ethylene-based resin composition that is excellent in flexibility (embeddability of steps) and heat resistance without being subjected to crosslinking treatment, and adhesiveness. Another object of the present invention is to provide an inexpensive solar cell sealing material excellent in electrical insulation, moisture permeability, moldability, and process handling. Furthermore, the objective of this invention is providing the solar cell module containing it.

  As a result of intensive investigations to solve the above problems, the present inventors have found that a resin composition containing an ethylene copolymer and an ethylene-vinyl acetate copolymer, either or both of which are ethylenically unsaturated It has been found that the above problem can be solved by a resin composition which is a modified product modified with a silane compound (C), and the present invention has been achieved. That is, the present invention relates to the following.

[1] An ethylene polymer that satisfies any of the following requirements a) to d), or a component (A) that is a modified product of the ethylenically unsaturated silane compound (C);
An ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 47% by mass, or a component (B) that is a modified product of the ethylenically unsaturated silane compound (C), and a resin composition comprising:
Either one or both of the component (A) and the component (B) is a modified product of the ethylenically unsaturated silane compound (C), and the total of the component (A) and the component (B) The resin composition whose content rate of the said component (B) is 5-50 mass%.
a) Density is 900-940 kg / m ³
b) 90-125 ° C melting peak temperature based on DSC
c) Melt flow rate (MFR2) measured at 190 ° C. and 2.16 kg load in accordance with JIS K-6721 is 0.1 to 100 g / 10 minutes d) Mw / Mn is 1.2 to 3.5

[2] The resin composition according to [1], wherein the ethylene polymer satisfies the following requirement e).
e) The amount of metal residue is 0.1-50 mass ppm
[3] The amount of modification by the ethylenically unsaturated silane compound (C) is 0.1 to 5 parts by mass with respect to 100 parts by mass in total of the component (A) and the component (B). ] Or the resin composition as described in [2].

[4] A sheet molded article comprising the resin composition according to any one of [1] to [3].
[5] A solar cell encapsulant comprising the resin composition according to any one of [1] to [3].

[6] An ethylene polymer satisfying any of the following requirements a) to d), an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 47% by mass, and an ethylenically unsaturated silane compound (C And a step of preparing a mixture containing an organic oxide, and a step of obtaining a sheet molding by melt extrusion molding the mixture,
In the melt extrusion molding, the ethylene polymer and / or the ethylene-vinyl acetate copolymer is graft-modified with the ethylenically unsaturated silane compound (C).
a) Density is 900-940 kg / m ³
b) 90-125 ° C melting peak temperature based on DSC
c) Melt flow rate (MFR2) measured at 190 ° C. and 2.16 kg load in accordance with JIS K-6721 is 0.1 to 100 g / 10 minutes d) Mw / Mn is 1.2 to 3.5
[7] An ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 47% by mass, impregnated with a mixed solution containing an ethylenically unsaturated silane compound (C) and an organic peroxide, and the following requirements including a step of obtaining a sheet molding by melt extrusion molding a mixture with an ethylene polymer satisfying any of a) to d),
In the melt extrusion molding, the ethylene polymer and / or the ethylene-vinyl acetate copolymer is graft-modified with the ethylenically unsaturated silane compound (C).
a) Density is 900-940 kg / m ³
b) 90-125 ° C melting peak temperature based on DSC
c) Melt flow rate (MFR2) measured at 190 ° C. and 2.16 kg load in accordance with JIS K-6721 is 0.1 to 100 g / 10 minutes d) Mw / Mn is 1.2 to 3.5

  According to the present invention, an inexpensive solar system that does not require a crosslinking treatment, has excellent flexibility (step embedding property) and heat resistance, and has excellent adhesion, electrical insulation, moisture permeability, moldability, and process handling properties. A battery sealing material can be obtained.

  The resin composition of this invention contains a component (A) and a component (B). Component (A) is an ethylene polymer that satisfies any of the following requirements a) to d), or a modified product of the ethylenically unsaturated silane compound (C). On the other hand, the component (B) is a modified product of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 47% by mass or an ethylenically unsaturated silane compound (C) thereof. However, one or both of the component (A) and the component (B) is a modified product of the ethylenically unsaturated silane compound (C).

Component (A) Component (A) is an ethylene polymer that satisfies all of the requirements a) to d) (hereinafter, also referred to as “ethylene polymer (A ′)”) or is made of ethylene. It is a modified product modified with a functional unsaturated silane compound (C). The ethylene polymer (A ′) is not particularly limited as long as it satisfies the requirements of a) to d) and has a structural unit derived from ethylene.

  Examples of the ethylene-based polymer (A ′) include an ethylene homopolymer or a copolymer of ethylene and at least one α-olefin having 3 to 20 carbon atoms. Here, the α-olefin having 3 to 20 carbon atoms includes propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and 1-dodecene. Examples include 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicocene, and α-olefins having 4 to 10 carbon atoms are preferable.

  Furthermore, the copolymer of ethylene and a cyclic olefin can also be mentioned. Here, as the cyclic olefin, a norbornene derivative, a tricyclo-3-decene derivative, a tricyclo-3-undecene derivative, a tetracyclo-3-dodecene derivative, a pentacyclo-4-pentadecene derivative, a pentacyclopentadecadiene derivative, a pentacyclo-3- Pentadecene derivatives, pentacyclo-4-hexadecene derivatives, pentacyclo-3-hexadecene derivatives, hexacyclo-4-heptadecene derivatives, heptacyclo-5-eicosene derivatives, heptacyclo-4-eicosene derivatives, heptacyclo-5-heneicosene derivatives, octacyclo-5-docosene Derivatives, nonacyclo-5-pentacocene derivatives, nonacyclo-6-hexacocene derivatives, cyclopentadiene-acenaphthylene adducts, 1,4-methano-1,4,4a, 9a-tetrahydrofluorene derivatives, 1,4-methano- , 4, 4a, 5,10,10a hexa hydro anthracene derivatives, and the like cycloalkylene derivative having 3 to 20 carbon atoms.

  Among them, tetracyclo [4.4.0.12,5.17,10] -3-dodecene derivatives and hexacyclo [6.6.1.13,6.110,13.02,7.09,14] -4-Heptadecene derivatives are preferred, and tetracyclo [4.4.0.12,5.17,10] -3-dodecene is particularly preferred.

  These α-olefins and cyclic olefins may be used alone or in combination of two or more of α-olefin and cyclic olefin. These α-olefins and cyclic olefins may form a random copolymer with ethylene or a block copolymer.

As described above, the ethylene polymer (A ′) satisfies the following requirements a) to d).
a) Density: The density of the ethylene-based polymer (A ′) is 900 to 940 kg / m ³ , preferably 905 to 935 kg / m ³ , more preferably 905 to 930 kg / m ³ , and still more preferably. It is 900 to 925 kg / m ³ , more preferably 905 to 925 kg / m ³ , and 905 to 923 kg / m ³ .

When the density of the ethylene-based polymer (A ′) is less than 900 kg / m ³ , the heat resistance of the resin composition is lowered, and the performance as a solar cell sealing material may not be sufficient. For example, when power is generated with the solar cell module tilted, if the solar cell encapsulant has low heat resistance, the solar cell encapsulant softens, and the glass substrate or electrode of the solar cell gradually shifts. The glass substrate may slide down.

Further, when the density of the ethylene polymer (A ′) is less than 900 kg / m ³ , when the resin composition of the present invention is used as a sheet, blocking occurs and the sheet is unwound from the sheet winding body. Or stickiness to the chill roll and the embossing roll occurs at the time of forming the sheet, and it tends to be difficult to control the thickness of the sheet and form the sheet.

On the other hand, if the density of the ethylene polymer (A ′) is more than 940 kg / m ³ , the flexibility of the resin composition is lowered. Therefore, when the solar cell module is to be sealed with the sealing sheet made of the resin composition of the present invention, the silicon crystal cell is cracked and the electrodes (for example, surface electrodes made of silver) are peeled off.

Further, when the density of the ethylene-based polymer (A ′) exceeds 940 kg / m ³ , the resin composition becomes difficult to melt. Therefore, when the sealing sheet made of the resin composition of the present invention is to be laminated, it is necessary to make the laminating temperature higher than the general laminator temperature of 150 ° C., or the first laminator temperature at 150 ° C. It may be necessary to perform a one-stage vacuum and preheating time for a long time.

  The density of the ethylene polymer (A ′) depends on the comonomer content such as α-olefin of the ethylene polymer (A ′). That is, the lower the comonomer content in the ethylene polymer (A ′), the higher the density, and the higher the comonomer content, the lower the density. For this reason, the density of the ethylene-based polymer (A ′) can be adjusted by adjusting the comonomer / ethylene composition ratio.

  Further, it is known that the comonomer content in the ethylene polymer (A ′) is determined by the composition ratio (comonomer / ethylene) of the comonomer and ethylene in the polymerization system (for example, Walter Kaminsky, Makromol. Chem). 193, p.606 (1992)).

  The density of the ethylene polymer (A ′) can be measured by a density gradient tube method.

  b) Melting peak temperature: The melting peak temperature based on DSC of the ethylene-based polymer (A ′) is 90 to 125 ° C., preferably 90 to 120 ° C., and more preferably 90 to 115 ° C.

  When the melting peak temperature of the ethylene polymer (A ′) is less than 90 ° C., the heat resistance of the resin composition is lowered, and the performance as a solar cell sealing encapsulant may be insufficient. If the heat resistance of the solar cell encapsulant is not sufficient, as described above, the glass substrate or electrode of the solar cell may gradually shift and the glass substrate may slide down. Further, when the melting peak temperature of the ethylene polymer (A ′) is less than 90 ° C., as described above, blocking occurs when the resin composition of the present invention is used as a sheet, or the thickness of the sheet at the time of forming the sheet. Control and sheet molding tend to be difficult.

  When the melting peak temperature of the ethylene polymer (A ′) is more than 125 ° C., the flexibility of the resin composition is lowered. If the flexibility of the solar cell encapsulant is not sufficient, as described above, cracking of the silicon crystal cell and peeling of the electrode (for example, a surface electrode made of silver) occur. On the other hand, if the melting peak temperature of the ethylene polymer (A ′) exceeds 125 ° C., the resin composition is difficult to melt. Therefore, as described above, it may be necessary to increase the laminating temperature, or it may be necessary to perform the first stage of vacuum and preheating time for a long time.

  The melting peak temperature of the ethylene polymer (A ′) depends on the comonomer content such as α-olefin of the ethylene polymer (A ′) as well as the density. That is, the lower the comonomer content in the ethylene polymer (A ′), the higher the melting peak, and the higher the comonomer content, the lower the melting peak. For this reason, the melting peak of the ethylene polymer (A ′) can be adjusted by adjusting the comonomer / ethylene composition ratio.

  The melting peak temperature of the ethylene polymer (A ′) is measured by DSC, and can be specifically measured under the following conditions. That is, 1) Prepare a sample of an ethylene polymer (A ′) packed in a special aluminum pan of about 5 mg, and 2) set it on a DSC7 manufactured by PerkinElmer, Inc. and set the temperature from 0 ° C. to 200 ° C. to 320 ° C. Temperature was raised at ℃ / min; after holding at 200 ° C. for 5 minutes; temperature was lowered from 200 ° C. to 0 ° C. at 10 ° C./min; held at 0 ° C. for further 5 minutes and then heated at 10 ° C./min . 3) From the obtained endothermic curve, the peak peak of the melting peak is determined as the melting peak temperature.

  c) Melt flow rate MFR: Melt flow rate (MFR2) measured at 190 ° C. and 2.16 kg load according to JIS K-6721 of ethylene polymer (A ′) is 0.1 to 100 g. / 10 minutes, preferably 0.5 to 50 g / 10 minutes, and more preferably 0.5 to 20 g / 10 minutes.

  When the MFR2 of the ethylene-based polymer (A ′) is less than 0.1 g / 10 minutes, the fluidity of the resin composition is lowered, and the productivity at the time of sheet extrusion molding is lowered. If the MFR2 of the ethylene polymer (A ′) is more than 100 g / 10 minutes, on the contrary, the fluidity is too high, so that sheet molding is difficult. Further, mechanical properties such as the tensile strength of the sheet are lowered.

  The melt flow rate (MFR2) of the ethylene polymer (A ′) can be measured at 190 ° C. and a 2.16 kg load in accordance with JIS K-6721.

  d) Molecular weight distribution Mw / Mn: The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) of the ethylene-based polymer (A ′) is 1. .2 to 3.5, preferably 1.2 to 3.2, and more preferably 1.2 to 2.8.

  An ethylene polymer having Mw / Mn of less than 1.2 must usually be produced by a living polymerization method. In the living polymerization method, the amount of the catalyst per unit weight of the polymer is increased, which increases the production cost of the polymer and is industrially disadvantageous. On the other hand, when the Mw / Mn of the ethylene polymer is more than 3.5, the impact strength of the resulting ethylene resin composition is lowered. Further, the sheet becomes sticky, the sheet is blocked, and it is difficult to unwind the sheet from the sheet winding body.

  The ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the ethylene-based polymer (A ′) is generally affected by the composition distribution. For example, when an ethylene polymer (A ′) is produced by batch slurry polymerization, Mw / Mn tends to decrease if the comonomer conversion rate is kept low, and Mw / Mn tends to increase if the comonomer conversion rate is increased. is there. The conversion rate of comonomer is the ratio of the amount of comonomer that has undergone polymerization reaction to the amount of comonomer charged. Further, by shortening the polymerization time, the conversion rate of the comonomer becomes low, and the alteration of the active species of the polymerization catalyst can be suppressed. For this reason, the composition distribution also becomes narrow and Mw / Mn tends to be small. On the other hand, by increasing the polymerization time, the comonomer conversion rate is increased and the polymerization catalyst is also altered. For this reason, composition distribution spreads and Mw / Mn tends to increase.

  Furthermore, in continuous gas phase polymerization or solution polymerization, the average residence time is shortened to suppress alteration of the polymerization catalyst and the composition distribution becomes narrow, so Mw / Mn tends to be small. On the other hand, when the average residence time is lengthened, the active species of the polymerization catalyst are altered and the composition distribution is broadened, so that Mw / Mn tends to increase.

  The molecular weight distribution (Mw / Mn) of the ethylene polymer (A ′) can be measured using a water permeation chromatograph Alliance GPC-2000 type.

The ethylene-based polymer (A ′) may further satisfy the following requirement e).
e) Amount of metal residue: The amount of metal residue contained in the ethylene polymer (A ′) is 0.1 to 50 ppm by mass, preferably 0.1 to 45 ppm by mass, and more preferably 0.00. It is 1-40 mass ppm, Most preferably, it is 5-40 mass ppm. The metal residue of the ethylene polymer (A ′) is derived from, for example, an active species of a polymerization catalyst in the production thereof, and is derived from, for example, a transition metal of a metallocene compound, but is not particularly limited.

  In order to make the amount of the metal residue of the ethylene polymer (A ′) less than 0.1 mass ppm, a deashing operation of the polymerization catalyst from the ethylene polymer is essential. For this reason, the plant fixed cost, the utility cost, and the like are high, and thus the manufacturing cost tends to be high. Furthermore, since a large amount of acid, alkali, or chelating agent is required to perform the deashing treatment, there is a high possibility that the acid, alkali, or chelating agent remains in the ethylene polymer (A ′). Become. When an ethylene-based polymer in which acid, alkali, or chelating agent remains is used as a raw material for a solar cell encapsulant, the remaining acid, alkali, or chelating agent may corrode the electrodes of the solar cell module. .

  Moreover, long-term storage stability falls that the quantity of the metal residue of an ethylene-type polymer (A ') is less than 0.1 mass ppm. This is because metal residues can be a catcher for acids, alkalis, etc. If there are too few metal residues, acids, alkalis, etc. cannot be deactivated, which breaks the bond between glass and solar cell encapsulant. Presumed to be easier.

  Further, when a small amount of metal (Ti, Zr, Hf, etc.) contained in a general metallocene compound as a polymerization catalyst component is present in the ethylene-based polymer (A ′), these activate organic peroxides. Therefore, grafting efficiency is improved by performing graft modification of the ethylene-based polymer (A ′) with the ethylenically unsaturated silane compound (C) in the presence of an organic peroxide. Although details will be described later, graft modification may be performed by, for example, extrusion modification.

  In addition, the above metals (Ti, Zr, Hf, etc.) activate the organic peroxide remaining in a trace amount in the ethylene-based resin composition at the time of laminating, so that the free metal remaining in the ethylene-based resin composition It is presumed that the ethylenically unsaturated silane compound (C) can be graft-modified and the adhesive strength is improved.

  On the other hand, when the amount of the metal residue of the ethylene polymer (A ′) is more than 50 ppm by mass, the volume specific resistance and dielectric breakdown resistance of the resin composition are insufficient. Moreover, the long-term storage stability of a resin composition will fall that the quantity of a metal residue is more than 50 mass ppm. For example, when component (A) is used as a material for a solar cell encapsulant, it is speculated that metal ions will be dissolved over time in the adhesion surface with the glass and break the bond between the glass and the solar cell encapsulant. The

  The amount of the metal residue of the ethylene polymer (A ′) depends on the polymerization activity of the polymerization catalyst used for the production thereof. That is, when an ethylene polymer (A ′) is produced using a polymerization catalyst having a high polymerization activity, the amount of catalyst for the monomer can be reduced, so that the amount of metal residue can be reduced. Therefore, using a polymerization catalyst having a high polymerization activity is one of the preferred methods for reducing the metal residue. In addition, the polymerization reaction is carried out at the optimum polymerization temperature of the polymerization catalyst used, the polymerization reaction pressure is increased as much as possible, and the monomer concentration per polymerization catalyst is also increased to increase the polymerization activity and reduce the metal residue. It is one of the techniques.

  The polymerization catalyst for producing the ethylene-based polymer (A ′) may include an organoaluminum oxy compound, a compound that reacts with the metallocene compound to form an ion pair, an organoaluminum compound, and the like together with the metallocene compound. . Suppressing these addition amounts is also one suitable method for reducing metal residues.

  In addition, improving the polymerization activity using various techniques can be a suitable technique for reducing metal residues.

  On the other hand, a method of reducing the amount of metal residue remaining in the ethylene-based polymer by decalcification treatment using a chelating agent such as acid and alkali or methyl acetoacetate is also conceivable. However, if an acid and an alkali or a chelating agent remain in the ethylene polymer (A ′), corrosion of the thin film electrode is promoted, which may not be a suitable technique.

  The amount of the metal residue contained in the ethylene polymer (A ′) can be measured as follows. 1) Wet-decompose ethylene-based polymer (A ′) and then make a constant volume with pure water. 2) Quantify metal elements with an ICP emission spectrometer (ICPS-8100, manufactured by Shimadzu Corporation). The total amount of is the metal residue.

Method for Producing Ethylene Polymer (A ′) The ethylene polymer (A ′) is obtained by homopolymerizing ethylene by using a conventionally known ethylene polymerization catalyst or having 3 to 20 ethylene and carbon atoms. It can be produced by copolymerizing at least one α-olefin or a cyclic olefin.

  Examples of the ethylene-based polymerization catalyst include a Ziegler-Natta catalyst, a metallocene catalyst, and the like. Of these ethylene polymerization catalysts, a metallocene catalyst containing a metallocene compound having a high polymerization activity per unit transition metal is preferred. This is because an ethylene polymer (A ′) with less metal residue can be obtained without performing a deashing treatment.

  As the metallocene compound, for example, the metallocene compounds described in JP-A-2006-077261, JP-A-2008-231265, JP-A-2005-314680, and the like can be used. Further, a metallocene compound different from the metallocene compound described in the above-mentioned patent document may be used as long as an ethylene polymer (A ′) that satisfies the requirements of a) to e) is obtained. Two or more metallocene compounds may be blended and used.

  The ethylene polymer (A ′) is obtained by (co) polymerizing ethylene or the like using a polymerization catalyst (metallocene catalyst) containing a metallocene compound. The polymerization catalyst (metallocene catalyst) may contain a cocatalyst together with the metallocene compound. A preferred cocatalyst is at least one selected from the group consisting of (II-1) an organoaluminum oxy compound, (II-2) a compound that reacts with a metallocene compound to form an ion pair, and (II-3) an organoaluminum compound. More than a kind of compounds.

  Regarding the (II-1) organoaluminum oxy compound that is a promoter, (II-2) a compound that reacts with the metallocene compound (I) to form an ion pair, and (II-3) an organoaluminum compound, for example, Various compounds described in JP 2006-077261 A, JP 2008-231265 A, JP 2005-314680 A, and the like can be used. However, it is not limited to the compounds described in these documents as long as an ethylene polymer satisfying the above requirements a) to e) is obtained.

  Each component of the polymerization catalyst may be put into the polymerization atmosphere separately, or may be put into the polymerization atmosphere after contacting in advance. Further, the metallocene compound and the promoter component may be used by being supported on a fine particle inorganic oxide carrier described in, for example, JP-A-2005-314680.

  The ethylene polymer (A ′) can be obtained by any of the conventionally known gas phase polymerization methods or liquid phase polymerization methods such as slurry polymerization methods and solution polymerization methods. Preferably, it is produced by a gas phase polymerization method or a slurry polymerization method with high activity and less metal residue.

  In the slurry polymerization method and the solution polymerization method, monomers are polymerized in a solvent. Examples of the solvent include aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane; benzene, toluene, Aromatic hydrocarbons such as xylene; inert hydrocarbon solvents such as halogenated hydrocarbons such as ethylene chloride, chlorobenzene, dichloromethane or mixtures thereof. Of these inert hydrocarbon solvents, aliphatic hydrocarbons and alicyclic hydrocarbons are preferred.

When producing an ethylene-based polymer (A ′) using a polymerization catalyst containing a metallocene compound,
The amount of the metallocene compound is preferably 10 ⁻⁹ to 10 ⁻¹ mol, preferably 10 ⁻⁸ to 10 ⁻² mol, per liter of reaction volume. When the amount of the metallocene compound is less than 10 ⁻⁹ mol / l, the frequency of the polymerization reaction is reduced and the polymerization activity is lowered. On the other hand, when the amount of the metallocene compound exceeds m10 ⁻¹ mol / l, the metal residue of the ethylene polymer (A ′) may increase.

  (II-1) The amount of the organoaluminum oxy compound is such that the molar ratio [(II-1) / M] of the compound (II-1) to the total transition metal atom (M) of the metallocene compound (I) is 1 to 1. The amount is 10,000, preferably 10 to 5,000. The amount of the compound (II-2) is such that the molar ratio [(II-2) / M] to the total transition metal (M) in the metallocene compound (I) is 0.5 to 50, preferably 1 to 20. The amount is such that The amount of compound (II-3) is usually 0 to 5 mmol, preferably about 0 to 2 mmol, per liter of polymerization volume.

  When the ethylene polymer (A ′) is produced by a solution polymerization method, the polymerization temperature is 0 to 200 ° C., preferably 20 to 190 ° C., more preferably 40 to 180 ° C. In the case of solution polymerization, when the polymerization temperature is less than 0 ° C., the polymerization activity is extremely lowered, so that it is not practical in terms of productivity. Further, in the polymerization temperature range of 0 ° C. or higher, as the temperature increases, the solution viscosity at the time of polymerization decreases, and it is easy to remove the heat of polymerization. However, when the polymerization temperature exceeds 200 ° C., the polymerization activity is extremely lowered, and therefore, it is not practical in terms of productivity.

  The polymerization pressure in the solution polymerization is normal pressure to 10 MPa gauge pressure, preferably normal pressure to 8 MPa gauge pressure. The polymerization can be carried out in any of batch, semi-continuous and continuous methods. The reaction time (average residence time when the polymerization reaction is carried out in a continuous manner) varies depending on conditions such as catalyst concentration and polymerization temperature, and can be selected as appropriate, but is 1 minute to 3 hours, preferably 10 minutes to 2 .5 hours. Furthermore, the polymerization can be performed in two or more stages having different reaction conditions.

  The molecular weight of the resulting ethylene polymer (A ′) can also be adjusted by changing the hydrogen concentration and polymerization temperature in the polymerization reaction system within the scope of the present invention. Further, it can be adjusted by the amount of the promoter in the polymerization catalyst. When hydrogen is added, the amount is suitably about 0.001 to 5,000 NL per kg of the ethylene / α-olefin copolymer to be produced.

About component (B) The resin composition of this invention contains a component (B). Component (B) is an ethylene-vinyl acetate copolymer (hereinafter, also referred to as ethylene-vinyl acetate copolymer (B ′)), which is a copolymer of ethylene and vinyl acetate, or is made of an ethylenic polymer. A modified product modified with a saturated silane compound (C). In the ethylene-vinyl acetate copolymer (B ′), the ratio of vinyl acetate units in all polymerization component units is preferably 10 to 47% by mass, and more preferably 13 to 35% by mass.

  The melt flow rate (MFR) measured at 190 ° C. of the ethylene-vinyl acetate copolymer (B ′) is preferably 3 to 30 g / 10 min, and more preferably 5 to 25 g / 10 min.

  The ethylene-vinyl acetate copolymer (B ′) may contain other copolymer components in addition to ethylene and vinyl acetate. Examples of other copolymer components include vinyl esters such as vinyl formate, vinyl glycolate, vinyl propionate and vinyl benzoate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid and ethacrylic acid or salts thereof; acrylic acid Examples include unsaturated esters such as alkyl esters and alkyl methacrylates.

  The ethylene-vinyl acetate copolymer (B ′) may be a mixture of two or more ethylene-vinyl acetate copolymers. For example, two or more ethylene-vinyl acetate copolymers having different vinyl acetate contents or different melt flow rates may be mixed.

  As described above, one or both of component (A) and component (B) contained in the resin composition of the present invention is a modified product modified with an ethylenically unsaturated silane compound (C).

  A well-known thing can be used for an ethylenically unsaturated silane compound (C), and there is no restriction | limiting in particular. Specifically, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxy-ethoxysilane), γ-glycidoxypropyl-trimethoxysilane, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltri Methoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethylethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyl Methyldimethylmethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoe Til) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl) -Butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-isocyanatopropyltriethoxysilane and the like are used.

  Preferred examples of the ethylenically unsaturated silane compound (C) include γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxy. Silane, 3-acryloxypropyltrimethoxysilane and the like are included. This is because the resin modified with these tends to improve adhesion performance.

  More preferred examples of the ethylenically unsaturated silane compound (C) include vinyltriethoxysilane, vinyltrimethoxysilane, and 3-acryloxypropyltrimethoxysilane. This is because the steric hindrance of the reactive group is small and the reaction efficiency of the graft modification reaction to the ethylene polymer (A ′) is high. The resin modified with these has particularly good adhesiveness, and the lamination time when the sheet is laminated with each adherend can be shortened.

  The amount of the ethylenically unsaturated silane compound (C) used for modification is 0.1 to 5 parts by mass, preferably 0.1 to 100 parts by mass in total of the component (A) and the component (B). It is -4 mass parts, More preferably, it is 0.3-4 mass parts, More preferably, it is 0.3-2.5 mass parts, Most preferably, it is 0.5-2.5 mass parts.

  When the blending amount of the ethylenically unsaturated silane compound (C) is in the above range, it is preferable because the adhesiveness of the resin composition is sufficiently enhanced and the transparency and flexibility of the resin composition are not adversely affected.

(Modification with ethylenically unsaturated silane compound (C))
As described above, the resin composition of the present invention contains the component (A) and the component (B), and one or both of them is a modified product modified with the ethylenically unsaturated silane compound (C). . The modification method by the ethylenically unsaturated silane compound (C) is not particularly limited. For example, 1) A resin composition containing an ethylene copolymer (A ′) and an ethylene-vinyl acetate copolymer (B ′) is prepared, and the resulting preparation is made of an ethylenically unsaturated silane compound (C). Method of modifying 2) After modifying ethylene copolymer (A ′) and / or ethylene-vinyl acetate copolymer (B ′) separately with ethylenically unsaturated silane compound (C) There is a method of mixing. In handling, a method of modifying a resin composition containing an ethylene copolymer (A ′) and an ethylene-vinyl acetate copolymer (B ′) with an ethylenically unsaturated silane compound (C) is preferable.

  In order to modify the ethylene polymer (A ′) and / or the ethylene-vinyl acetate copolymer (B ′) with the ethylenically unsaturated silane compound (C), conventional methods such as an extrusion melt modification method and a solution modification method have been used. A known modification method can be used. Among them, the extrusion melt modification method is preferable because the production cost is low.

  In the technique by the extrusion melt modification method, (i) a mixed resin pellet of an ethylene-based polymer (A ′) and an ethylene-vinyl acetate copolymer (B ′), and an ethylenically unsaturated silane compound (C), It is modified by extrusion melting in the presence of an organic peroxide. The modification can be a graft modification.

  The organic peroxide used in the extrusion melt modification method is obtained by graft-modifying an ethylene polymer (A ′) and / or an ethylene-vinyl acetate copolymer (B ′) with an ethylenically unsaturated silane compound (C). There are no particular restrictions on the type of the material. Preferred examples of the organic peroxide include 2,5-dimethyl-2,5-di (t-butylperoxy) hexene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butyl peroxy-2-ethylhexyl carbonate, t-butyl peroxybenzoate and the like are included.

  In order to extrusion-melt modify the ethylene polymer (A ′) and / or the ethylene-vinyl acetate copolymer (B ′) and the ethylenically unsaturated silane compound (C), a conventionally known single-screw extruder, A twin screw extruder or the like can be used. The extrusion temperature is usually equal to or higher than the melting point of the ethylene polymer (A ′), for example, 100 to 300 ° C., preferably 150 to 260 ° C. The melting time is preferably 0.5 to 10 minutes.

  In the extrusion melt modification method, when the ethylene polymer (A ′) and / or the ethylene-vinyl acetate copolymer (B ′) is modified with the radical polymerizable ethylenically unsaturated silane compound (C), A reducing substance may be added. By adding the reducing substance, the graft amount of the radical polymerizable ethylenically unsaturated silane compound (C) can be improved.

  In the extrusion melt modification method, a part of the mixed resin pellet of the ethylene polymer (A ′) and the ethylene-vinyl acetate copolymer (B ′) is mixed with the ethylene polymer (A ′) and the ethylene-vinyl acetate copolymer. It may be a mixed resin powder with the polymer (B ′). By having the powder together with the pellets, the ethylenically unsaturated silane compound (C) or the organic peroxide is easily impregnated into the pellets and the powder, and the density unevenness thereof hardly occurs.

  That is, in the technique of the extrusion melt modification method, (ii) resin pellets of ethylene polymer (A ′) or ethylene-vinyl acetate copolymer (B ′) and ethylene polymer (A ′) or ethylene-acetic acid are used. The powdery resin of the vinyl copolymer (B ′) and the ethylenically unsaturated silane compound (C) may be modified by extrusion melting in the presence of an organic peroxide. Or (iii) an ethylene-based polymer impregnated with an ethylene-based polymer (A ′) or an ethylene-vinyl acetate copolymer (B ′) pellet, an ethylenically unsaturated silane compound (C) and an organic peroxide. The powdered resin of the coalescence (A ′) or ethylene-vinyl acetate copolymer (B ′) may be modified by extrusion melting.

  Ethylenically unsaturated silane compound (C) with respect to 100 parts by mass (total when powder and pellets are used) of ethylene polymer (A ′) and ethylene-vinyl acetate copolymer (B ′) in extrusion melt modification ) Is usually 0.1 to 5 parts by mass, preferably 0.1 to 4 parts by mass, more preferably 0.3 to 4 parts by mass, and still more preferably 0.3 to 4 parts by mass. 2.5 parts by mass, particularly preferably 0.5 to 2.5 parts by mass.

  The blending amount of the organic peroxide with respect to a total of 100 parts by mass of the ethylene-based polymer (A ′) and the ethylene-vinyl acetate copolymer (B ′) in the extrusion melt modification (the total when powder and pellets are used) is It is preferably 0 to 1.0 part by mass, and more preferably 0.01 to 0.5 part by mass.

  In the resin composition of the present invention, the content of component (B) is preferably 5 to 50% by mass, and 10 to 45% by mass with respect to the total of component (A) and component (B). More preferably, it is more preferably 15 to 35% by mass. When there is too little content rate of a component (B), the softness | flexibility of a resin composition will fall. When there is too much content rate of a component (B), the water vapor permeability of a resin composition may not fully be suppressed, or insulation may not fully be acquired.

  In the resin composition of the present invention, the component (A) and the component (B) preferably form a sea-island structure, and the component (B) preferably forms an island structure.

About other components The resin composition of this invention may mix | blend the adhesiveness imparting agent. Preferable examples of the adhesion-imparting agent that can be added to the solar cell encapsulant include a silane coupling agent. Specific examples of the silane coupling agent include γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyl-tris- (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-ethoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and N-β- ( Aminoethyl) -γ-aminopropyltrimethoxysilane and the like. The silane compound used as the adhesion-imparting agent may be a silane-modified resin.

  From the viewpoint of the stability of the adhesion-imparting agent, alkoxysilanes are preferably used. This is because alkoxysilanes are relatively stable at room temperature and in a neutral pH range. On the other hand, when producing a solar cell module, there exists a problem that the adhesive force of the sealing film for solar cells is hard to express from the stability.

  The content of the silane coupling agent used as an adhesiveness imparting agent in the solar cell encapsulant is preferably 0.1 to 3.0 parts by weight with respect to 100 parts by weight of the polymer component, More preferably, it is 0.2 to 1.5 parts by weight.

  As described above, the silane coupling agent as the adhesion-imparting agent preferably has a reactive group (such as an alkoxy group or a halogen group) bonded to a silicon atom. The reactive group bonded to the silicon atom is a member in contact with the solar cell sealing film in the solar cell module (that is, a solar cell formed of silicon or the like, or a surface protection member formed of an inorganic substance such as glass). This is because a chemical bond or a physical bond such as a hydrogen bond can be formed by reacting with. This bonding is considered to greatly improve the adhesion between the solar cell sealing film and the protective member.

  The reactive group bonded to the silicon atom in the silane coupling agent as the adhesiveness imparting agent has higher activity and the higher the number of the groups, the higher the adhesion of the solar cell encapsulant. On the other hand, if the activity of the reactive group is too high, the adhesion-imparting agent reacts during storage of the solar cell encapsulant, and when the solar cell module is produced using the encapsulant, adhesion is imparted. You may not be able to do it.

  The solar cell encapsulant of the present invention can contain other optional additives. Examples of optional additives include colorants, ultraviolet absorbers, anti-aging agents, anti-discoloring agents, heat-resistant stabilizers, ultraviolet absorbers, light stabilizers and the like.

  Examples of colorants include inorganic pigments such as metal oxides and metal powders; organic pigments such as azo, phthalocyanine, azo, and acidic or basic dye lakes.

  Examples of UV absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 4- Benzophenone series such as dodecyloxy-2-hydroxybenzophenone; 2- (2′-hydroxy-5-methylphenyl) benzotriazole, 2- (3-tertiarybutyl-2-hydroxy-5-methylphenyl) -5-chlorobenzo Benzotriazole systems such as triazole; salicylate systems such as phenyl salicylate and pt-butylphenyl salicylate are included.

  Light stabilizers include amines, phenols, bisphenyls and hindered amines such as di-t-butyl-p-cresol and bis (2,2,6,6-tetramethyl-4 -Piperazil) sebacate and the like. In particular, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate is preferred for increasing the charge decay time at 75 ° C. to 100 ° C. In addition, hydroquinone, hydroquinone monomethyl ether, p-benzoquinone and methylhydroquinone may be included in improving the stability of the ethylene / α-olefin / diene copolymer and / or the ethylene / α-olefin copolymer. Good.

  The resin composition of the present invention may be formed into a sheet shape. Although a shaping | molding means is not specifically limited, It can obtain by extrusion molding methods (T-die extrusion molding method etc.). For example, a mixture of an ethylene polymer (A ′), an ethylene-vinyl acetate copolymer (B ′) and an ethylenically unsaturated silane compound (C) is melt-kneaded and extruded as a molten resin sheet, and then cooled and solidified. By doing so, a sheet molded product is obtained. When extruding into a sheet, the ethylene polymer (A ′) and the ethylene-vinyl acetate copolymer (B ′) can be modified with the ethylenically unsaturated silane compound (C). Therefore, the modification process and the molding process can be the same process.

  The sheet-formed resin composition of the present invention can be used, for example, as a sealing sheet, preferably as a solar cell sealing sheet. The thickness of the solar cell sealing sheet is preferably about 100 to 2000 μm. Moreover, it is preferable that the surface of the sheet | seat for solar cell sealing is embossed. Embossing improves cushioning and deaeration in the lamination process.

  The solar cell sealing sheet of the present invention is used for sealing solar cells into a module. The solar cell module includes, for example, a front surface side transparent protective member, a solar cell sealing member, a solar cell sealed by the sealing member, and a back surface side protective member. Thus, the photovoltaic cell is sealed by the sealing member between the front surface side transparent protective member and the back surface side protective member. This sealing member can be obtained with the solar cell sealing material of the present invention. For example, the sealing member can be formed by disposing the solar cell sealing sheet of the present invention on the front surface side and the back surface side of the solar battery cell and performing pressure bonding sealing.

  Solar cell modules are classified into a type in which the edge of the module is fixed with a frame and a type in which no frame is fixed. There is a type called a laminated glass type as a type that does not have a frame to be fixed. In the laminated glass type, a solar battery cell and a sealing member are sandwiched between two pieces of glass (corresponding to a front surface side transparent protective member and a back surface side protective member).

  In the case of a laminated glass module that does not have a frame to be fixed, since there is no frame, there is a possibility that the substrate is likely to be displaced unless the adhesiveness between the sealing material and the substrate and the heat resistance of the sealing material are sufficient. This problem can be solved by increasing the adhesion and heat resistance (melting point / softening point) of the sealing material.

  Further, in the case of a laminated glass type module, when the step is embedded (filled with the sealing material) in the step portion due to the thickness of the wiring material of the extraction electrode, the glass follows the shape and deforms not a little. The deformed glass is subjected to a force to return to the original (flat) shape, and residual stress is generated. Since this residual stress is strongly applied to the sealing material and its adhesion interface, peeling may occur in a region where the residual stress cannot be tolerated during or after lamination. This problem can be solved by increasing the flexibility of the sealing member.

  Since the resin composition of the present invention is highly compatible with adhesiveness, heat resistance and flexibility, it is particularly suitably used as a sealing member for a glass type solar cell module.

Surface side transparent protective member The surface side transparent protective member of a solar cell module does not have a restriction | limiting in particular, The surface side protective member generally used in a solar cell module can be used. Since the surface side transparent protective member is located on the outermost layer of the solar cell module, the performance to ensure long-term reliability in outdoor exposure of the solar cell module including weather resistance, water repellency, contamination resistance and mechanical strength It is preferable to comprise. Moreover, in order to utilize sunlight effectively, it is preferable that it is a highly transparent sheet | seat with a small optical loss.

  Examples of materials for the surface-side transparent protective member of the solar cell module include resin films made of polyester resin, fluorine resin, acrylic resin, ethylene / vinyl acetate copolymer, cyclic olefin (co) polymer, glass, etc. Etc. are included.

  The glass as the surface-side transparent protective member is a glass substrate having a total light transmittance of 80% or more, preferably 90% or more, of light having a wavelength of 350 to 1400 nm. The glass as the surface-side transparent protective member is generally a white plate glass with little absorption in the infrared region; however, it may be blue plate glass as long as the thickness is 3 mm or less, and to the output characteristics of the solar cell module. There is almost no adverse effect.

  Further, the glass as the surface-side transparent protective member may be tempered glass that has been heat-treated in order to increase mechanical strength, but may also be float plate glass that has not been heat-treated. Since the glass as the surface side transparent protective member needs to withstand wind pressure, it is generally a glass substrate having a thickness of about 3 mm and is reinforced with a frame (aluminum frame). A laminated glass type solar cell module does not have this frame.

  Moreover, in order to improve the adhesiveness between the surface-side transparent protective member and other members such as a sealing member, the surface-side transparent protective member is preferably subjected to corona treatment or plasma treatment. Further, the light-receiving surface side of the front surface side transparent protective member is usually subjected to antireflection coating or embossing in order to suppress light reflection.

Back side protection member There is no restriction | limiting in particular in the back side protection member of a solar cell module, The back side protection member generally used in a solar cell module can be used. You may comprise a back surface side protection member with the material similar to the said surface side transparent protection member.

  The back surface side protection member of the solar cell module needs to have a function of preventing moisture from entering the solar cell module. Since the sealing member of the solar cell module may have water absorption and moisture permeability, the function of preventing the moisture from entering the back side protection member is important.

  The back surface side protection member of the solar cell module desirably has light resistance against reflected light from the ground or the like, heat resistance that can withstand a temperature of 60 to 100 ° C., and the like. On the other hand, since the back surface side protection member does not assume the passage of sunlight, the transparency required for the front surface side protection member is not necessarily required.

  A light reflection function or a scattering function may be imparted to the back surface side protection part. Thereby, the utilization efficiency of light can be improved. There is no particular limitation on the method for imparting the reflection function or the scattering function. For example, a metal layer may be provided in order to impart the reflection function, and in order to impart the scattering function, light scattering fine particles may be provided. What is necessary is just to add.

Solar cell The solar cell in the solar cell module is not particularly limited as long as it can generate power using the photovoltaic effect of the semiconductor. Examples of solar cells include silicon (single crystal, polycrystalline, amorphous) solar cells, compound semiconductors (Groups 3-5, 2-6, etc.) solar cells, wet solar cells, Organic semiconductor solar cells and the like are included. Among these, a polycrystalline silicon solar cell is preferable from the viewpoint of balance between power generation performance and cost.

  Both silicon solar cells and compound semiconductor solar cells have excellent characteristics as solar cells, but are easily damaged by external stress and impact. The sealing member obtained from the solar cell sealing material of the present invention is excellent in flexibility, can absorb stress and impact on the solar cell, and effectively suppress the damage of the solar cell. . Therefore, in a preferable solar cell module, the sealing member obtained from the solar cell sealing material of the present invention is directly joined to the solar cell.

  In the solar battery cell, a collecting electrode for taking out the generated electricity is arranged. The collecting electrode refers to a bus bar electrode, a finger electrode, or the like. The current collecting electrode may be arranged on both the front and back surfaces of the solar battery cell; however, if the current collecting electrode is arranged on the light receiving surface, the current collecting electrode blocks light and the power generation efficiency is lowered. Can occur.

  In order to improve the power generation efficiency, a back contact solar cell that does not require a collector electrode on the light receiving surface may be used. In one aspect of the back contact solar cell, p-doped regions and n-doped regions are alternately provided on the back surface side provided on the opposite side of the light receiving surface of the solar cell. In another aspect of the back contact solar cell, a p / n junction is formed on a substrate provided with a through hole (through hole), and the surface (light-receiving surface) side of the through hole inner wall and the through hole peripheral portion on the back surface side is formed. A doped layer is formed, and the current on the light receiving surface is taken out on the back side.

  The solar cell module may have an arbitrary member as appropriate. Typically, an adhesive layer, a shock absorbing layer, a coating layer, an antireflection layer, a back surface rereflection layer, a light diffusion layer, and the like can be provided, but not limited thereto. There are no particular limitations on the positions at which these layers are provided, and the layers can be provided at appropriate positions in consideration of the purpose of providing such layers and the characteristics of such layers.

  Hereinafter, the present invention will be specifically described by way of examples. However, the scope of the present invention is not limited by the examples.

[Synthesis Example 1] Synthesis of ethylene polymer (PE-1) [Preparation of solid catalyst component]
A solid catalyst component containing dimethylsilylene bis (3-methylcyclopentadienyl) zirconium dichloride as a metallocene compound was prepared by the method described in JP-A-9-328520. Specifically, 3.0 g of silica dried at 250 ° C. for 10 hours was suspended in 50 ml of toluene, and then cooled to 0 ° C. Thereafter, 17.8 ml of a toluene solution of methylaluminoxane (Al = 1.29 mmol / ml) was added dropwise over 30 minutes. At this time, the temperature in the system was kept at 0 ° C. Then, it was made to react at 0 degreeC for 30 minutes, then, it heated up to 95 degreeC over 30 minutes, and was made to react at the temperature for 4 hours. Thereafter, the temperature was lowered to 60 ° C., and the supernatant was removed by a decantation method.

  The obtained solid component was washed twice with toluene and then resuspended in 50 ml of toluene. Into this system, 11.1 ml of a toluene solution (Zr = 0.0103 mmol / ml) of dimethylsilylenebis (3-methylcyclopentadienyl) zirconium dichloride (diastereoisomer mixing ratio 1: 1) was added at 20 ° C. It was added dropwise over 30 minutes. Subsequently, it heated up to 80 degreeC and made it react at that temperature for 2 hours. Thereafter, the supernatant was removed and washed twice with hexane to obtain a solid catalyst containing 2.3 mg of zirconium per 1 g.

[Preparation of prepolymerization catalyst]
A prepolymerized catalyst was obtained by the method described in JP-A-9-328520. Specifically, 4 g of the solid catalyst obtained above was resuspended in 200 ml of hexane. In this system, 5.0 ml of a decane solution of triisobutylaluminum (1 mmol / ml) and 0.36 g of 1-hexene were added, and ethylene was prepolymerized at 35 ° C. for 2 hours. As a result, a prepolymerized catalyst containing 2.2 mg of zirconium per 1 g of the solid catalyst and prepolymerized with 3 g of polyethylene was obtained.

[polymerization]
830 ml of dehydrated and purified hexane was charged into a 2 liter stainless steel autoclave sufficiently purged with nitrogen, and the inside of the system was replaced with a mixed gas of ethylene and hydrogen (hydrogen content: 0.7 mol%). Next, the system was heated to 60 ° C., 1.5 mmol of triisobutylaluminum, 179 ml of 1-hexene, and the prepolymerized catalyst prepared above were added so as to be 0.015 mg atom in terms of zirconium atom.

  Thereafter, a mixed gas of ethylene and hydrogen having the same composition as above was introduced, and polymerization was started at a total pressure of 3 MPaG. Thereafter, only the mixed gas was supplied, the total pressure was kept at 3 MPaG, and polymerization was carried out at 70 ° C. for 1.5 hours. After the completion of the polymerization, the obtained polymer was filtered and dried overnight at 80 ° C. to obtain 105 g of a powdery ethylene polymer (PE-1).

The ethylene polymer (PE-1) was converted into an ethylene polymer (with a die diameter = 190 ° C.) using a single screw extruder (screw diameter 20 mmφ · L / D = 28) manufactured by Thermo Plastic Co., Ltd. PE-1) Pellets were obtained. The physical properties are shown in the table below.

[Synthesis Example 2] Synthesis of ethylene polymer (PE-2) Catalysts and resins were synthesized by the method described in International Publication Banflet WO2007 / 034920.

[Complex synthesis]
Synthesis of di (p-tolyl) methylene (η5-cyclopentadienyl) (η5-octamethyloctahydrodibenzofluorenyl) zirconium dichloride

(i) Synthesis of cyclopentadienyl (octamethyloctahydrodibenzofluorenyl) di-p-tolylmethane A 300 ml two-necked flask equipped with a magnetic stirrer, three-way cock and dropping funnel was thoroughly purged with nitrogen, and then octamethyl 2.98 g (7.71 mmol) of octahydrodibenzofluorene was added, and 60 mL of dehydrated tetrahydrofuran was added to make a colorless and transparent solution. While being cooled in an ice water bath, 5.2 mL (8.1 mmol) of a 1.56 mol / L n-butyllithium / hexane solution was gradually added, and then stirred at room temperature for 7 hours under a nitrogen atmosphere to obtain an orange solution. While cooling in a methanol / dry ice bath, 2.40 g (9.27 mmol) of 6,6-di-p-tolylfulvene previously dissolved in 30 mL of dehydrated tetrahydrofuran was gradually added over 20 minutes using a dropping funnel. Thereafter, the temperature was gradually raised to room temperature, and the mixture was stirred at room temperature for 21 hours under a nitrogen atmosphere to obtain a dark red solution. 100 mL of a saturated aqueous ammonium chloride solution was gradually added, followed by 100 mL of diethyl ether. The resulting bilayer solution was transferred to a 300 mL separatory funnel and shaken several times, and then the colorless and transparent aqueous layer was removed. Subsequently, the obtained organic layer was washed twice with 100 mL of water and once with 100 mL of saturated saline, and dried over anhydrous magnesium sulfate for 30 minutes. The solid was filtered off and the solvent was distilled off with a rotary evaporator. The resulting solid was washed with hexane to obtain cyclopentadienyl (octamethyloctahydrodibenzofluorenyl) di-p-tolylmethane as a white solid. . The yield was 3.55 g (5.50 mmol, 71.3% yield).

Identification of cyclopentadienyl (octamethyloctahydrodibenzofluorenyl) di-p-tolylmethane was carried out by ¹ H-NMR spectrum and FD-MS spectrum. The measurement results are shown below. In the NMR assignment results below, OMOHDBFlu is an abbreviation for η5-octamethyloctahydrodibenzofluorenyl group.

¹ H-NMR spectrum (270 MHz, CDCl3): d / ppm 0.8-1.7 (m, Me (OMOHDBFlu), 24H), 2.1-2.4 (br, CH2 (OMOHDBFlu), 8H), 2.7-3.1 (br, CH2 (Cp), 1H), 5.2-5.4 (m, CH (9-OMOHDBFlu), 1H), 5.8-6.5 (br, Cp, 4H), 6.7-7.5 (br, Ar (OMOHDBFlu) & Ar (p-tol ), 10H), 7.29 (s, Ar (OMOHDBFlu), 2H)
FD-MS spectrum: M / z 644 (M +)

(ii) Synthesis of di (p-tolyl) methylene (η5-cyclopentadienyl) (η5-octamethyloctahydrodibenzofluorenyl) zirconium dichloride After nitrogen substitution, 1.10 g (1.56 mmol) of cyclopentadienyl (octamethyloctahydrodibenzofluorenyl) di-p-tolylmethane was added, and 30 mL of dehydrated diethyl ether was added to make a colorless and transparent solution. While gradually cooling in an ice-water bath, 2.1 mL (3.30 mmol) of a 1.56 mol / L n-butyllithium / hexane solution was gradually added, and then stirred at room temperature for 20 hours under a nitrogen atmosphere. A slurry consisting of the solution was obtained. After adding 0.552 g (1.46 mmol) of zirconium tetrachloride / tetrahydrofuran complex (1: 2) while cooling in a methanol / dry ice bath, the temperature was gradually raised to room temperature and stirred at room temperature for 24 hours under a nitrogen atmosphere. A slurry consisting of a red pink solid and a red solution was obtained. The red solid obtained by distilling off the solvent under reduced pressure was washed with hexane, followed by extraction with dichloromethane to obtain a red solution. The solvent of this solution was distilled off under reduced pressure to obtain di (p-tolyl) methylene (η5-cyclopentadienyl) (η5-octamethyloctahydrodibenzofluorenyl) zirconium dichloride as a red pink solid. The yield was 0.825 g (1.02 mmol, yield 70.2%).

  Identification of di (p-tolyl) methylene (η5-cyclopentadienyl) (η5-octamethyloctahydrodibenzofluorenyl) zirconium dichloride was performed by 1H-NMR spectrum and FD-MS spectrum. The measurement results are shown below.

¹ H-NMR spectrum (270 MHz, CDCl3): d / ppm 0.82 (s, Me (OMOHDBFlu), 6H), 0.93 (s, Me (OMOHDBFlu), 6H), 1.40 (s, Me (OMOHDBFlu), 6H) , 1.46 (s, Me (OMOHDBFlu), 6H), 1.5-1.7 (m, CH2 (OMOHDBFlu), 8H), 2.32 (s, Me, 6H), 5.53 (t, J = 2.6 Hz, Cp, 2H), 6.17 (s, Ar (OMOHDBFlu), 2H), 6.25 (t, J = 2.6 Hz, Cp, 2H), 7.1-7.3 (m, Ar (p-tol), 4H), 7.6-7.8 (m, Ar ( p-tol), 4H), 8.03 (s, Ar (Flu), 2H)
FD-MS spectrum: M / z 804 (M +)

[polymerization]
Di (p-tolyl) methylene (cyclopentadienyl) (octamethyloctahydrodibenzo) in which dehydrated n-hexane was dissolved in 6.0 L / hr, n-hexane in a completely stirred and mixed continuous polymerization tank having an internal volume of 1 L A hexane solution (0.16 mmol / L) of fluorenyl) zirconium dichloride was prepared into a toluene solution (80 mmol / L) of 0.0190 mmol / hr, methylaluminoxane (TMAO-341: manufactured by Tosoh Finechem). A hexane solution (12 mmol / L) of 19.0 mmol / hr of Al and triisobutylaluminum was introduced at a rate of 1.8 mmol / hr. At the same time, ethylene is continuously fed into the polymerization tank at 680 g / hr, hydrogen at 0.0291 g / hr, and dehydrated 1-octene at 0.68 kg / hr, and the polymerization tank is polymerized so that the reaction pressure is 6.9 MPa-G. A polymerization solution was continuously withdrawn from the upper part of the tank, and a polymerization reaction was performed at a polymerization temperature of 170 ° C. A small amount of isopropyl alcohol is added as a quenching agent to the polymerization solution continuously withdrawn from the polymerization tank, and 0.05% by mass of Irganox 1076 (manufactured by Ciba Specialty Chemicals Co., Ltd.) is added as a heat-resistant stabilizer. The polymer was precipitated by flashing. Then it dried 8 hours at 120 ° C. in a vacuum oven under N ₂ flow. The ethylene conversion of this polymerization was 94.1%, and the ethylene polymer yield was 0.814 kg / hr.

The ethylene polymer (PE-2) obtained by the above polymerization was subjected to a die temperature = 190 ° C. using a single screw extruder (screw diameter 20 mmφ · L / D = 28) manufactured by Thermo Plastic Co., Ltd. The pellet of the ethylene polymer (PE-2) was obtained. The physical properties are shown in the table below.

[Example 1]
A blend of ethylene-based polymer (PE-1) and ethylene-vinyl acetate copolymer (EVA) (vinyl acetate content 28%, MFR 15 g / 10 min, tensile modulus 20 MPa) at a mass ratio of 4: 1 is 100. 1.0 part by weight of vinyl methoxysilane, 0.02 part by weight of 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2-hydroxy-4-normal- 0.3 parts by mass of octyloxybenzophenone, 0.1 parts by mass of bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and tris (2,4-di-tert-butylphenyl) Add 0.025 parts by mass of phosphite and 0.025 parts by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, and dry-blend to make an ethylene Polymeric A blend was obtained.

  Next, the obtained blend of ethylene polymer was melt-kneaded with a single screw extruder (screw diameter 20 mmφ · L / D = 28) manufactured by Thermo Plastic Co., Ltd. Lip shape; 270 × 0.8 mm), and extrusion at a die temperature of 200 ° C. After cooling at a roll temperature of 30 ° C., an embossing roll is used as the first cooling roll at a winding speed of 1.0 m / min. And molded. Thereby, the sheet | seat which consists of an ethylene-type resin composition containing the modified body which modified | denatured the ethylene-type polymer with the ethylenically unsaturated silane compound was obtained. The maximum thickness tmax of the sheet was 450 μm.

[Example 2]
Except for blending ethylene-based polymer (PE-1) and ethylene-vinyl acetate copolymer (EVA) (vinyl acetate content 28%, MFR 15 g / 10 min, tensile modulus 20 MPa) at a mass ratio of 3: 2, Similarly to Example 1, a sheet having a maximum sheet thickness tmax of 450 μm was produced.

[Example 3]
Except for blending ethylene-based polymer (PE-2) and ethylene-vinyl acetate copolymer (EVA) (vinyl acetate content 28%, MFR 15 g / 10 min, tensile elastic modulus 20 MPa) at a mass ratio of 4: 1. In the same manner as in Example 1, a sheet having a maximum thickness tmax of 450 μm was prepared.

[Comparative Example 1]
100 parts by mass of ethylene-vinyl acetate copolymer (EVA) (vinyl acetate content 28%, MFR 15 g / 10 min, tensile modulus 20 MPa), 0.5 parts by mass of γ-methacryloxypropyltrimethoxysilane, 2 , 5-dimethyl-2,5-di (t-butylperoxy) hexane, 0.5 parts by mass, tert-butylperoxy-2-ethylhexyl carbonate, 2.0 parts by mass, triallyl isocyanurate 0.5 parts by weight, 0.3 parts by weight of 2-hydroxy-4-normal-octyloxybenzophenone as a weathering stabilizer, and 0 by bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate 0.1 part by mass, 0.025 part by mass of tris (2,4-di-tert-butylphenyl) phosphite as a heat stabilizer, and octadecyl-3- (3,5-di-t-butyl-4- Hide Were added to 0.025 parts by mass Kishifeniru) propionate, overnight left to for impregnation, to obtain a blend of EVA.

  The obtained EVA blend was melt-kneaded with a single screw extruder (screw diameter 20 mmφ · L / D = 28) manufactured by Thermo Plastic Co., Ltd., and then a coat hanger type T die (lip shape; 270 × 0.8 mm) was extruded at a die temperature of 100 ° C., cooled at a roll temperature of 30 ° C., and then molded using an embossing roll as a first cooling roll at a winding speed of 1.0 m / min. Thereby, an EVA sheet was obtained. The maximum thickness tmax of the sheet was 450 μm.

[Comparative Example 2]
Without blending the ethylene-vinyl acetate copolymer EVA, a sheet having a maximum thickness tmax of 450 μm was produced in the same manner as in Example 1 using only the ethylene polymer (PE-1).

[Comparative Example 3]
Without blending the ethylene-vinyl acetate copolymer EVA, a sheet having a maximum thickness tmax of 450 μm was produced in the same manner as in Example 1 using only the ethylene polymer (PE-2).

[Comparative Example 4]
290 g of polyvinyl butyral (PVB) (polyvinyl alcohol content = 22.0% by weight, polyvinyl acetate content = 0.2% by weight, Mw = 104300 g / mol), 210 g of dipropylene glycol dibenzoate (= DPGDB) as a plasticizer, Were mixed to obtain a blend. Mixing was performed using a laboratory mixer (manufacturer: Papenmeier, model: TGHKV20 / KGU63; Brabender, model: 826801).

  The obtained blend was extruded at a melt temperature of 150 ° C. using a single screw extruder equipped with a slot die (manufacturer: Haake) to obtain a film having a thickness of 0.8 mm.

  The following characteristics were evaluated for the sheets obtained in each Example and Comparative Example. The results are shown in Table 3. However, only Comparative Example 1 showed the properties of the crosslinked sheet or the properties of lamination under the lamination conditions including the crosslinking step.

[Tensile modulus]
The tensile modulus of the produced sheet in the MD direction (sheet take-up direction) was measured according to JIS K7113.

[Embeddability]
On a 3.2 mm thick glass substrate, a 5 mm wide / 300 μm thick aluminum plate, a 450 μm thick sealing sheet, and a 3.2 mm thick glass plate were sequentially laminated as a pseudo electrode. The obtained laminate was placed on a hot plate adjusted to 150 ° C. in a vacuum laminator, vacuumed for 3 minutes, and then heated for 9 minutes. However, only Comparative Example 1 was placed on a hot plate adjusted to 125 ° C. in a vacuum laminator, vacuumed for 3 minutes, heated for 5 minutes, and further heated in an oven at 150 ° C. for 50 minutes for curing. It was. Thus, a pseudo laminated glass module of glass / pseudo electrode / sealing sheet / glass was produced. After sufficiently cooling this, the presence or absence of bubbles or peeling was observed around the pseudo electrode.

[Adhesive strength]
The produced sheet was laminated on glass, placed on a hot plate adjusted to 150 ° C. in a vacuum laminator, vacuumed for 3 minutes, and then heated for 9 minutes. However, only Comparative Example 1 was placed on a hot plate adjusted to 125 ° C. in a vacuum laminator, vacuumed for 3 minutes, heated for 5 minutes, and further heated in an oven at 150 ° C. for 50 minutes for curing. It was. This produced the glass / sealing sheet laminate. The sealing sheet on this laminated body was cut into a width of 10 mm, and the peel strength by 180 degree peeling against the glass as the adherend was measured. The peel strength by 180 degree peel was measured using an Instron tensile tester Instron 1123 at 23 ° C., a span interval of 30 mm, a tensile speed of 300 mm / min, and an average value of three measurements was adopted. "

[Volume resistivity]
The volume resistivity of the produced sheet was measured under the condition of 70 ° C. according to JIS K6911.

[Water vapor transmission rate]
The water vapor transmission rate of the produced sheet was measured using the Mocon method under the conditions of a temperature of 40 ° C. and a relative humidity of 90% in accordance with JIS K7129.

[Water absorption rate]
The water absorption rate of the produced sheet was measured by the Karl Fischer method after pre-curing for 100 hours under conditions of a temperature of 40 ° C. and a relative humidity of 90%.

[Heat resistant creep resistance]
On the glass having a thickness of 3.2 mm / width 1 cm, a sealing sheet and a glass having a thickness of 3.2 mm / width 1 cm were sequentially laminated. Two glasses were laminated without overlapping each other. The obtained laminate was placed on a hot plate adjusted to 150 ° C. in a vacuum laminator, vacuumed for 3 minutes, and then heated for 9 minutes. However, only Comparative Example 1 was placed on a hot plate adjusted to 125 ° C. in a vacuum laminator, vacuumed for 3 minutes, heated for 5 minutes, and further heated in an oven at 150 ° C. for 50 minutes for curing. It was. In the obtained laminate, the area of the sealing sheet sandwiched between two glasses was adjusted to 1 cm ² .

The obtained laminate was put in an oven at 105 ° C., one glass was fixed, a weight was attached to the other glass so as to be 25 g / cm ^2, and the plate was allowed to stand for 24 hours under a load. Then, the laminated body was taken out and it was confirmed whether the glass was displaced from the initial position.

  In Examples 1 to 3 using a sealing material made of a resin obtained by modifying an ethylene polymer and an ethylene-vinyl acetate copolymer with silane, evaluation of embedding property is good and evaluation of heat resistant creep property is also good. That is, it turns out that the sealing materials of Examples 1 to 3 have both flexibility and adhesiveness. The water vapor permeability is sufficiently low, and the resistance value (electrical insulation) is sufficiently high.

  On the other hand, in the comparative example 1 using the sealing material which consists only of ethylene-vinyl acetate copolymer, a bridge | crosslinking process is required. Furthermore, the water vapor transmission rate is high and the resistance value is not sufficiently increased. On the other hand, in Comparative Examples 2 to 3 using a sealing material composed only of an ethylene-based polymer, it can be seen that the embedding evaluation is not good and the flexibility is not sufficient. Moreover, in the comparative example 3, heat resistance creep property evaluation is not good and it turns out that adhesiveness is not enough. In Comparative Example 4 using polyvinyl butyral PVB, the water vapor transmission rate is high and the resistance value is not sufficiently increased.

The resin composition of the present invention can be suitably used as a solar cell encapsulant, and in particular, a solar cell encapsulant on the back side of a crystalline solar cell module, a solar cell module for a thin film, particularly a laminated glass type module solar It is useful as a battery sealing material.

Claims (7)

An ethylene polymer that satisfies any of the following requirements a) to d), or a component (A) that is a modified product of the ethylenically unsaturated silane compound (C);
An ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 47% by mass, or a component (B) that is a modified product of the ethylenically unsaturated silane compound (C), and a resin composition comprising:
Either one or both of the component (A) and the component (B) is a modified product of the ethylenically unsaturated silane compound (C), and the total of the component (A) and the component (B) The resin composition whose content rate of the said component (B) is 5-50 mass%.
a) Density is 900-940 kg / m ³
b) 90-125 ° C melting peak temperature based on DSC
c) Melt flow rate (MFR2) measured at 190 ° C. and 2.16 kg load in accordance with JIS K-6721 is 0.1 to 100 g / 10 minutes d) Mw / Mn is 1.2 to 3.5 The resin composition according to claim 1, wherein the ethylene polymer satisfies the following requirement e).
e) The amount of metal residue is 0.1-50 mass ppm   The modification amount by the ethylenically unsaturated silane compound (C) is 0.1 to 5 parts by mass with respect to 100 parts by mass in total of the component (A) and the component (B). The resin composition described in 1.   The sheet molding which consists of a resin composition as described in any one of Claims 1-3.   The solar cell sealing material which consists of a resin composition as described in any one of Claims 1-3. An ethylene polymer satisfying any of the following requirements a) to d), an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 47% by mass, an ethylenically unsaturated silane compound (C), Including a step of preparing a mixture containing an organic oxide, and a step of obtaining a sheet molding by melt extrusion molding the mixture,
In the melt extrusion molding, the ethylene polymer and / or the ethylene-vinyl acetate copolymer is graft-modified with the ethylenically unsaturated silane compound (C).
a) Density is 900-940 kg / m ³
b) 90-125 ° C melting peak temperature based on DSC
c) Melt flow rate (MFR2) measured at 190 ° C. and 2.16 kg load in accordance with JIS K-6721 is 0.1 to 100 g / 10 minutes d) Mw / Mn is 1.2 to 3.5 An ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 47% by mass, impregnated with a mixed solution containing an ethylenically unsaturated silane compound (C) and an organic peroxide, and the following requirements a) to a step of obtaining a sheet molding by melt extrusion molding a mixture with an ethylene-based polymer satisfying any of d),
In the melt extrusion molding, the ethylene polymer and / or the ethylene-vinyl acetate copolymer is graft-modified with the ethylenically unsaturated silane compound (C).
a) Density is 900-940 kg / m ³
b) 90-125 ° C melting peak temperature based on DSC
c) Melt flow rate (MFR2) measured at 190 ° C. and 2.16 kg load in accordance with JIS K-6721 is 0.1 to 100 g / 10 minutes d) Mw / Mn is 1.2 to 3.5