JP2012207144A - Ethylene-based resin composition, solar cell sealing material and solar cell module using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ethylene-based resin composition and others, excellent in various characteristics such as adhesiveness, electric insulating property, transparency, moldability and process stability, and having improved productivity by eliminating a crosslinking process if necessary.SOLUTION: The ethylene-based resin composition comprises a modified product obtained by modifying an ethylene copolymer (A) satisfying all of the following requirements (a) to (e) with an ethylenically unsaturated silane compound comprising (B1) at least one kind selected from vinyl trimethoxysilane and 3-acroxypropyl trimethoxysilane and (B2) vinyl triethoxysilane. The requirements for the ethylene copolymer are: (a) density of 900 to 940 kg/m; (b) melt peak temperature of 90 to 125°C based on DSC; (c) a melt flow rate (MFR2) of 0.1 to 100 g/10 min measured in accordance with JIS K-6721 at 190°C under a load of 2.16 kg; (d) a Mw/Mn of 1.2 to 3.5; and (e) a metal residue concentration of 0.1 to 50 ppm.

Description

  The present invention relates to an ethylene-based resin composition having excellent adhesion to glass, a back sheet, and a thin film electrode, electrical insulation, transparency, moldability, long-term storage stability, cushioning properties and process moldability. The present invention relates to a solar cell encapsulant.

  The present invention further relates to a solar cell encapsulating sheet using such an ethylene-based resin composition, and a solar cell module using a solar cell encapsulating material or a solar cell encapsulating sheet.

  As global environmental problems and energy problems become more serious, solar energy is attracting attention as an energy source that is clean and does not run out of depletion. 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 is roughly divided into two types: a crystalline solar cell module and a thin film solar cell module. A crystalline solar cell module is a solar cell module protective sheet (surface protective member) / solar cell encapsulating sheet / crystalline solar cell formed of polycrystalline silicon, single crystal silicon, or the like. It is manufactured by the lamination method etc. which vacuum-suck the thing laminated | stacked in order of / solar cell sealing sheet / solar cell module protection sheet (back surface protection member).

  The thin film solar cell module is a thin film solar cell / solar cell made by forming a very thin film of several μm on a substrate such as glass with amorphous silicon or crystalline silicon. It is manufactured by the lamination method etc. which vacuum-suck what laminated | stacked in order of the sealing sheet for batteries / protection sheet for solar cell modules (back surface protection member). The solar cell module obtained in this way has weather resistance and is suitable for outdoor use such as a roof portion of a building.

  Conventionally, an ethylene-vinyl acetate copolymer (EVA) has been widely used as a material (solar cell encapsulant) constituting a solar cell encapsulating sheet from the viewpoint of its transparency and flexibility. (For example, see Patent Document 1). When using EVA 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 addition, there is a concern that components such as acetic acid gas generated by the decomposition of EVA may affect the solar cell element.

  As one of the measures for solving the above technical problem, a solar cell encapsulant containing an ethylene / α-olefin copolymer as a main component has also been proposed (see Patent Document 2). However, Patent Document 2 discloses any specifics regarding the physical properties of the ethylene / α-olefin copolymer for obtaining preferable characteristics (such as heat resistance, transparency, flexibility, and process stability) as a sealing material. It also does not disclose general guidelines. This is considered because the technique disclosed in Patent Document 2 is intended to achieve desired physical properties in combination with the crosslinking treatment on the premise of the crosslinking treatment.

  Furthermore, a solar cell encapsulating material using a metallocene linear low density polyethylene having a specific density range has also been proposed (see Patent Document 3). However, Patent Document 3 does not disclose any specific guidelines other than the density regarding the physical properties of the ethylene / α-olefin copolymer. This is presumably because the technique disclosed in Patent Document 3 is premised on the crosslinking treatment, and is intended to achieve desired physical properties together with the crosslinking treatment. Further, the solar cell encapsulant of Patent Document 3 may have low heat resistance and moisture resistance.

Further, the solar cell encapsulant is required to have high-speed adhesiveness, that is, high reactivity with the laminated glass, backsheet, power generation element and electrode when the module is formed. On the other hand, in storage and transportation, etc., it has contradictory properties such as suppressing the reaction such as condensation between resins even when exposed to high temperature or high humidity environment, and maintaining adhesiveness and resin fluidity even after long-term storage. Need to be satisfied.

JP-A-8-283696 JP 2000-091611 A Japanese Patent Laid-Open No. 2007-150069

  In view of the above-mentioned background, the object of the present invention is to suppress the condensation reaction between resins during storage and transportation in a solar cell encapsulant using an ethylene-based resin composition, and to laminate a glass or back during module formation. An object of the present invention is to provide an ethylene-based resin composition having high-speed adhesiveness with a sheet and satisfying these characteristics at a high level, a solar cell sealing material comprising the same, and a solar cell module including the sealing material.

  As a result of intensive studies to solve the above problems, the present inventors have found that the ethylene polymer (A) in a specific density range, melting point range, melt flow rate range, molecular weight distribution range, metal residue range, and An ethylene-based resin composition containing a modified polymer obtained by modifying an ethylene / α-olefin copolymer (C) with an ethylenically unsaturated silane compound (B). The present inventors have found that the problem can be solved by a resin composition using a combination of specific silane compounds as a compound, and reached the present invention.

  By using such an ethylene-based resin composition, the condensation reaction between the resins is suppressed during storage and transportation, and it has high-speed adhesiveness with the laminated glass and backsheet during module formation, and these characteristics are high. A solar cell encapsulant that satisfies the standards, has excellent adhesion, electrical insulation, transparency, moldability and process stability, and can improve productivity by omitting cross-linking as necessary It was found that can be obtained.

That is, the first of the present invention relates to the following ethylene resin composition.
[1] An ethylene resin composition containing a modified polymer obtained by modifying an ethylene polymer (A) satisfying the following requirements a) to e) with an ethylenically unsaturated silane compound (B). And
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 min d) Mw / Mn is 1.2 to 3.5
e) 0.1-50 ppm of metal residue
The ethylenically unsaturated silane compound (B) contains (B1) at least one selected from vinyltrimethoxysilane or 3-acryloxypropyltrimethoxysilane and (B2) vinyltriethoxysilane. Ethylene-based resin composition.

[2] The amount of the ethylenically unsaturated silane compound (B1) is 0.5 to 1.5 parts by weight with respect to 100 parts by weight of the ethylene polymer (A), and the ethylenically unsaturated silane compound The ethylene resin composition according to [1], wherein the blending amount of (B2) is 0.1 to 1.5 parts by weight.
[3] A modified polymer of the ethylene polymer (A) is obtained by extrusion melting a mixture of an ethylene polymer (A), an ethylenically unsaturated silane compound (B), and an organic peroxide. 1]. The ethylene-based resin composition according to 1].
[4] The ethylene type according to [1], wherein the amount of the ethylenically unsaturated silane compound (B) is 0.6 to 3.0 parts by weight with respect to 100 parts by weight of the ethylene polymer (A). Resin composition.
[5] The ethylene / α-olefin copolymer (C) is modified with (B1) at least one selected from vinyltrimethoxysilane or 3-acryloxypropyltrimethoxysilane and (B2) vinyltriethoxysilane. The ethylene resin composition according to any one of [1] to [4], further comprising the resulting modified copolymer.
[6] The ethylene-based resin composition according to [5], wherein the ethylene / α-olefin copolymer (C) satisfies the following requirement f).
f) Density is less than 850-900 kg / m ³
[7] A modified polymer of the ethylene / α-olefin copolymer (C) is a mixture of the ethylene / α-olefin copolymer (C), the ethylenically unsaturated silane compound (B) and the organic peroxide. The ethylene resin composition according to [5], obtained by extrusion melting.
[8] The ethylene resin composition according to [4], wherein the ethylene polymer (A) is a powder.
[9] The ethylene resin composition according to [4], wherein the ethylene polymer (A) is a mixture of powder and pellets.
[10] A mixture of an ethylene polymer (A) powder in which the mixture is pre-impregnated with an ethylenically unsaturated silane compound (B) and an organic peroxide, and a pellet of the ethylene polymer (A). The ethylene-based resin composition according to [4].
[11] The [1] to [10], further comprising at least one additive selected from the group consisting of an ultraviolet absorber (D), a light stabilizer (E), and a heat stabilizer (F). Ethylene-based resin composition.
[12] The ethylene / α-olefin copolymer (C) with respect to 100 parts by weight in total of the modified polymer of the ethylene-based polymer (A) and the modified polymer of the ethylene / α-olefin copolymer (C). The ethylene resin composition according to [5], wherein the content of the modified polymer is 90 parts by weight or less.
[13] A solar cell encapsulant comprising the ethylene resin composition according to [1].
[14] A solar cell encapsulant comprising the ethylene resin composition according to [5].
[15] A solar cell encapsulant comprising a sheet comprising the ethylene resin composition according to [1].
[16] The solar cell sealing material according to [15], wherein the solar cell sealing material is integrated with a back surface protection member for a solar cell module.
[17] A solar cell module obtained by using the solar cell sealing material according to [15].
[18] A thin-film solar cell module obtained by using the solar cell sealing material according to [15].
[19] A crystalline solar cell module obtained by using the solar cell sealing material according to [15] as a solar cell sealing material on the back surface side.

  According to the present invention, adhesion to glass, backsheet, and thin film electrode, electrical insulation, transparency, moldability, cushioning and process stability are excellent, and adhesion and fluidity are reduced during storage and transportation. It is possible to obtain an ethylene-based resin composition that is suppressed and excellent in long-term storage stability and a solar cell encapsulant including the same.

  Moreover, by using the solar cell sealing material of the present invention, it is possible to obtain a solar cell module excellent in economic efficiency such as cost in addition to the above-described excellent characteristics. The solar cell encapsulant of the present invention is particularly useful as a solar cell encapsulant for thin film solar cell modules and a solar cell encapsulant on the back side of a crystalline solar cell module.

[Ethylene resin composition]
The ethylene-based resin composition of the present invention includes a modified polymer of an ethylene-based polymer (A) that simultaneously satisfies the requirements a) to e) described later, and an ethylene / α-olefin copolymer (C) as necessary. The modified polymer may be further included.

[Silane modified product]
The modified polymer of the ethylene polymer (A) contained in the ethylene resin composition of the present invention is obtained by converting the ethylene polymer (A) into an ethylenically unsaturated silane compound (B) in the presence of an organic peroxide. ) Modified polymer obtained by modification. The modified polymer of ethylene / α-olefin copolymer (C) contained in the ethylene-based resin composition of the present invention is obtained by converting ethylene / α-olefin copolymer (C) to ethylene in the presence of an organic peroxide. It is a modified polymer obtained by modifying with a polymerizable unsaturated silane compound (B).

[Ethylene polymer (A)]
The ethylene polymer (A) as a raw material for the modified polymer of the ethylene polymer (A) has a constitutional unit derived from ethylene and satisfies the requirements of a) to e). There are no other restrictions.

The ethylene polymer (A) can be, for example, an ethylene homopolymer or a copolymer of ethylene and an α-olefin or a cyclic olefin.
The α-olefin in the copolymer of ethylene and α-olefin may be an α-olefin having 3 to 20 carbon atoms. Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene and 1-tetradecene. 1-hexadecene, 1-octadecene, 1-eicosene and the like. Of these, α-olefins having 4 to 10 carbon atoms are preferred, and specifically, 1-butene, 1-hexene and 1-octene are particularly preferred.

  Examples of the cyclic olefin in the copolymer of ethylene and cyclic olefin include norbornene derivatives, tricyclo-3-decene derivatives, tricyclo-3-undecene derivatives, tetracyclo-3-dodecene derivatives, pentacyclo-4-pentadecene derivatives, and pentacyclopentadeca. Diene derivatives, 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 1,4-methano-1,4,4a, 9a-tetrahydrofluorene derivative, 1,4-methano-1,4,4a, 5,10,10a-hexahydroanthracene derivative, and 3 to 20 carbon atoms Examples thereof include cycloalkylene derivatives.

  Among these, 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 [4.4.0.12,51.7,10] -3-dodecene is particularly preferred.

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

The ethylene polymer (A) used in the ethylene resin composition of the present invention satisfies the following requirements a) to e).
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 min d) Mw / Mn is 1.2 to 3.5
e) 0.1-50 ppm of metal residue

[Requirement a)]
The density of the ethylene-based polymer (A) is 900 to 940 kg / m ³ , preferably 900 to 935 kg / m ³ , more preferably 900 to 930 kg / m ³ , still more preferably 900 to 925 kg / m ³ , Preferably it is 905-925 kg / m < ³ >, Most preferably, it is 905-923 kg / m < ³ >.

When the density of the ethylene polymer (A) is less than 900 kg / m ³ , the heat resistance of the sealing material is lowered. For this reason, when power is generated by sunlight in a state where the solar cell module is tilted, the sealing material is softened, so that the glass and the electrodes gradually slide and the glass slides down. Also, sheet blocking occurs, making it difficult for the sheet to be unwound from the sheet winding body, and sticking to the chill roll and embossing roll occurs during sheet forming, making sheet thickness control and sheet forming difficult. There is a tendency. When the density of the ethylene polymer (A) is more than 940 kg / m ³ , the flexibility of the sealing material is lowered, and when the solar cell module is manufactured by lamination, the silicon crystal cell is cracked or the silver electrode is peeled off. Occurs. Moreover, since it is hard to melt | dissolve, it is necessary to make the temperature at the time of lamination molding higher than general laminator temperature 150 degreeC. Further, even at a general laminator temperature of 150 ° C., there is a problem that the first stage of vacuum and preheating time must be performed 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. 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)).

For this reason, the density of the ethylene-based polymer (A) can be adjusted by adjusting the composition ratio of comonomer / ethylene.
The density of the ethylene-based polymer (A) can be measured by a density gradient tube method.

[Requirement b)]
The melting peak temperature based on DSC of the ethylene polymer (A) is 90 to 125 ° C, preferably 90 to 120 ° C, 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 sealing material is lowered. For this reason, when power is generated by sunlight with the solar cell module tilted, the sealing material is softened, so that the glass and the electrodes gradually slide down. Further, blocking of the sheet occurs, making it difficult to unwind the sheet from the sheet winding body, and sticking to the chill roll and the embossing roll occurs at the time of forming the sheet, making it difficult to control the thickness of the sheet and form the sheet. There is a tendency. When the melting peak temperature of the ethylene polymer (A) exceeds 125 ° C., the flexibility of the sealing material is lowered, and cracking of the silicon crystal cell or peeling of the silver electrode occurs when the module is laminated. Further, since it is difficult to melt, the temperature at the time of laminate molding needs to be higher than a general laminator temperature of 150 ° C. Further, even at a general laminator temperature of 150 ° C., there arises a problem that the first stage of vacuum and preheating time must be taken for a long time.

  Similarly to the density, the melting peak temperature of the ethylene polymer (A) also 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 melting peak, and the higher the comonomer content, the lower the melting peak. 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)).

  For this reason, the melting peak of the ethylene-based polymer (A) can be adjusted by adjusting the comonomer / ethylene composition ratio.

  The melting peak temperature of the ethylene polymer (A) can be measured by DSC under the following conditions. That is, 1) Prepare a sample of an ethylene polymer (A) filled with about 5 mg of a special aluminum pan, and 2) set it on a DSC7 manufactured by PerkinElmer Co., Ltd. Temperature was raised at ℃ / min; after holding at 200 ° C. for 5 minutes; temperature from 200 ° C. to 0 ° C. was lowered 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.

[Requirement c)]
The melt flow rate (MFR2) measured at 190 ° C. under a load of 2.16 kg in accordance with JIS K-6721 of the ethylene polymer (A) is 0.1 to 100 g / 10 min, preferably 0.8. It is 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 ethylene-based resin composition containing the same decreases, and the productivity at the time of sheet extrusion molding decreases. If the MFR2 of the ethylene-based polymer (A) is more than 100 g / 10 minutes, on the contrary, the fluidity is too high and 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) strongly depends on the molecular weight of the ethylene polymer (A). That is, the smaller the melt flow rate (MFR2), the larger the molecular weight of the ethylene polymer (A), and the larger the melt flow rate (MFR2), the smaller the molecular weight of the ethylene polymer (A). In addition, it is known that the molecular weight of the ethylene polymer (A) is determined by the composition ratio (hydrogen / ethylene) of hydrogen and ethylene in the polymerization system (for example, Kazuo Soga, KODASHASHA “CATALYTIC OLEFIN POLYMERIZATION”). ", 376 (1990)). For this reason, the ethylene-type polymer (A) which satisfy | fills the requirement c) of this invention can be manufactured by adjusting the composition ratio of hydrogen / ethylene.
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.

[Requirement d)]
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 polymer (A) used in the ethylene resin composition of the present invention. Is 1.2 to 3.5, preferably 1.2 to 3.2, and more preferably 1.2 to 2.8.

  In order to obtain an ethylene-based polymer (A) having Mw / Mn of less than 1.2, it can usually be obtained only by living polymerization. For this reason, in order to obtain a living polymer, the catalyst amount per unit weight of the polymer is increased, and the production cost of the polymer is increased, which is industrially disadvantageous. When the Mw / Mn of the ethylene polymer (A) 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) is generally affected by the composition distribution. For example, when the ethylene-based polymer (A) is obtained by batch slurry polymerization, the Mw / Mn tends to decrease when the comonomer conversion rate is kept low, and the Mw / Mn tends to increase when the comonomer conversion rate is increased. The conversion rate of comonomer is the ratio of the amount used for the polymerization reaction to the charged amount of comonomer. 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, composition distribution also becomes narrow and Mw / Mn tends to be small. However, by increasing the polymerization time, the comonomer conversion rate is increased and the polymerization catalyst is altered. For this reason, composition distribution spreads and Mw / Mn tends to increase. Further, in the continuous gas phase polymerization or solution polymerization, the average residence time is shortened to suppress the alteration of the polymerization catalyst and the composition distribution becomes narrow, so that Mw / Mn tends to be small. However, when the average residence time is increased, 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-based polymer (A) can be measured using a gel permeation chromatograph Alliance GPC-2000 manufactured by Waters.

[Requirement e)]
The metal residue of the ethylene polymer (A) is 0.1 to 50 ppm, preferably 0.1 to 45 ppm, more preferably 0.1 to 40 ppm, and most preferably 5 to 50 ppm.

  If the metal residue of the ethylene-based polymer (A) is less than 0.1 ppm, the decalcification operation of the polymerization catalyst becomes essential, and the plant fixing cost, utility cost, etc. tend to increase, and the production cost tends to increase. . Furthermore, since a large amount of acid, alkali, or chelating agent used for the deashing treatment is required, the possibility that these acids, alkalis, or chelating agents remain in the ethylene polymer (A) increases. For this reason, when the said ethylene-type polymer (A) is used as a raw material of a solar cell sealing material, the acid etc. which remain | survived in the ethylene-type polymer (A), alkali, and a chelating agent, etc. Corrosion may occur. Moreover, long-term storage stability will fall that a metal residue is less than 0.1 ppm. This is presumably because the metal residue can be a catcher such as acid or alkali. That is, if the metal residue is too small, the causative substance that breaks the bond between the glass and the resin cannot be shut out, and it is assumed that bond breakage occurs frequently. Further, when a small amount of Ti, Zr, Hf or the like generally used for metallocene compounds is present as a polymerization catalyst for the ethylene-based polymer (A), these activate organic peroxides. The grafting efficiency of the ethylenically unsaturated silane compound (B) is improved. In addition, the above-described metals such as Ti, Zr, and Hf activate organic peroxides that remain in a trace amount in the ethylene resin composition at the time of laminating, and thus free ethylene remaining in the ethylene resin composition. It is presumed that the hydrophilic unsaturated silane compound (B) can be graft-modified and the adhesive strength is improved.

  On the other hand, when the metal residue of the ethylene-based polymer (A) exceeds 50 ppm, the metal residue causes a decrease in volume resistivity and dielectric breakdown resistance. Moreover, long-term storage stability will fall that a metal residue exceeds 50 ppm. This is because when an ethylene-based polymer (A) is used as a raw material for a solar cell encapsulating material, the metal becomes ions and melts with time on the adhesion surface with the glass, and the glass and resin (solar cell encapsulating) This is presumed to cut the bond with the material.

  The metal residue is derived from, for example, a transition metal of a metallocene compound that becomes an active species of the polymerization catalyst. The amount of metal residue depends on the level of polymerization activity. That is, if the polymerization catalyst has a high polymerization activity, the amount of catalyst for the monomer can be reduced, so that the metal residue can be reduced naturally. Therefore, using a polymerization catalyst having a high polymerization activity is one of the preferred methods for reducing the metal residue. In addition, polymerizing at the optimum polymerization temperature of the polymerization catalyst used, increasing the polymerization pressure as much as possible, and increasing the monomer concentration per polymerization catalyst are other suitable techniques for increasing the polymerization activity and reducing metal residues. One. In addition, for example, an organoaluminum oxy compound, a compound that reacts with the metallocene compound to form an ion pair, and an organoaluminum compound may be added to the metallocene compound. Suppressing these addition amounts as much as possible is one of the preferred methods 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, there is also a technique for reducing metal residues by decalcification treatment using a chelating agent such as acid and alkali or methyl acetoacetate. 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, and therefore, this is not a preferred method in the present invention.

  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 is metal residue.

[Method for producing ethylene polymer (A)]
The ethylene polymer (A) of the present invention can be produced by using a conventionally known ethylene polymerization catalyst component. Examples thereof include Ziegler-Natta catalysts and metallocene compounds. Among these, a metallocene compound having a high polymerization activity per unit transition metal exhibiting a polymerization activity is preferable because an ethylene polymer (A) having a small amount of 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. Moreover, as long as the ethylene polymer (A) satisfying the requirements of a) to e) is obtained, a metallocene compound having a structure different from that of the metallocene compound described in the patent document may be used. Two or more metallocene compounds may be blended and used.

The aspect of the preferable manufacturing method of the ethylene polymer (A) when using the metallocene compound is, for example,
(I) a conventionally known metallocene compound;
(II) selected from the group consisting of (II-1) an organoaluminum oxy compound, (II-2) a compound that reacts with the metallocene compound (I) to form an ion pair, and (II-3) an organoaluminum compound. At least one compound (sometimes called a cocatalyst);
Examples thereof include ethylene homopolymerization, copolymerization of at least one of ethylene and an α-olefin having 3 to 20 carbon atoms, or copolymerization of ethylene and a cyclic olefin under an olefin polymerization catalyst.
Here, (II-1) an organoaluminum oxy compound, (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 2006-0777261 A, JP 2008-231265 A, JP 2005-314680 A, and the like can be used. As long as the ethylene polymer (A) satisfying the above requirements a) to e) is obtained, a compound different from the various compounds described in the patent literature may be used. These compounds may be put into the polymerization atmosphere individually, or may be put into the polymerization atmosphere after contacting them 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.

[polymerization]
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 carried out by a gas phase polymerization method or slurry polymerization method which is highly active and reduces metal residues. Slurry polymerization and solution polymerization are carried out using propane, butane, pentane, hexane, heptane, octane, decane, dodecane, kerosene and other aliphatic hydrocarbons; cyclopentane, cyclohexane, methylcyclopentane and other alicyclic hydrocarbons; benzene, toluene Aromatic hydrocarbons such as xylene; halogenated hydrocarbons such as ethylene chloride, chlorobenzene, dichloromethane or mixtures thereof, or an inert hydrocarbon medium. Of these inert hydrocarbon solvents, aliphatic hydrocarbons and alicyclic hydrocarbons are preferred.

Using the metallocene compound as described above, ethylene homopolymerization, copolymerization of at least one ethylene and α-olefin having 3 to 20 carbon atoms, or copolymerization of ethylene and a cyclic olefin makes an ethylene-based polymer. When producing the union (A), the metallocene compound (I) is used in such an amount that it is 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 (I) is less than 10 ⁻⁹ mol / l, it is not preferable because the frequency of the polymerization reaction is reduced and the polymerization activity is lowered. Moreover, since the metal residue of an ethylene polymer (A) will increase when the quantity of a metallocene compound (I) exceeds 10 ^<-1 > mol / l, it is unpreferable.

  Compound (II-1) has a molar ratio [(II-1) / M] of Compound (II-1) to all transition metal atoms (M) in metallocene compound (I) of 1 to 10,000, preferably It is used in such an amount that it becomes 10-5000. Compound (II-2) has a molar ratio [(II-2) / M] to all transition metals (M) in metallocene compound (I) of 0.5 to 50, preferably 1 to 20. Used in various amounts. Compound (II-3) is used in an amount of 0 to 5 mmol, preferably about 0 to 2 mmol, per liter of polymerization volume.

  When the ethylene polymer (A) used in the present invention is obtained by “solution polymerization”, the polymerization temperature is 0 to 200 ° C., preferably 20 to 190 ° C., more preferably 40 to 180 ° C. In the solution polymerization according to the present invention, 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 is a normal pressure to 10 MPa gauge pressure, preferably a 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 in the polymerization system and the polymerization temperature within the scope of the present invention. Further, it can be adjusted by the amount of the compound (II) used. 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. The ethylene polymer (A) obtained by the polymerization method may be subjected to a conventionally known deashing treatment used in the method for producing an olefin polymer to remove the catalyst component and the fine particle inorganic oxide carrier. .

[Ethylenically unsaturated silane compound (B)]
The ethylenically unsaturated silane compound (B) used in the present invention contains (B1) at least one selected from vinyltrimethoxysilane or 3-acryloxypropyltrimethoxysilane and (B2) vinyltriethoxysilane.
The blending amount of the ethylenically unsaturated silane compound is preferably 0.6 to 3.0 parts by weight as the total of (B1) and (B2) with respect to 100 parts by weight of the ethylene polymer (A). 1.0 to 2.5 is more preferable. When the sum of (B1) and (B2) is in the above range, it is preferable in terms of high-speed adhesiveness.
The blending amount of the ethylenically unsaturated silane compound is preferably 0.5 to 1.5 parts by weight with respect to 100 parts by weight of the ethylene polymer (A). Similarly, the blending amount of (B2) is preferably 0.1 to 1.5 parts by weight. When the blending amount of (B1) and (B2) is in the above range, it is preferable in terms of storage stability.

[Ethylene / α-olefin copolymer (C)]
The resin composition of the present invention can further contain an ethylene / α-olefin copolymer (C) in addition to the ethylene polymer (A). Such an ethylene / α-olefin copolymer (C) is preferably used after being modified with an ethylenically unsaturated silane compound as described later.
The ethylene / α-olefin copolymer (C) used as a raw material for the modified polymer of the ethylene / α-olefin copolymer (C) is a single type of ethylene and an α-olefin having 3 to 20 carbon atoms. Or by copolymerizing two or more types in combination.

  Examples of the α-olefin having 3 to 20 carbon atoms include linear or branched α-olefins such as propylene, 1-butene, 2-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene and the like can be mentioned. The α-olefin that can be used in the present invention includes polar group-containing olefins. Examples of the polar group-containing olefin include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid and maleic anhydride, and metal salts such as sodium salts thereof; methyl acrylate, ethyl acrylate, Α, β-unsaturated carboxylic esters such as n-propyl acrylate, methyl methacrylate and ethyl methacrylate; vinyl esters such as vinyl acetate and vinyl propionate; unsaturated glycidyl such as glycidyl acrylate and glycidyl methacrylate And the like. Vinylcyclohexane, diene or polyene; aromatic vinyl compounds such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o, p-dimethylstyrene, methoxystyrene, vinylbenzoic acid, methyl vinylbenzoate , Vinyl benzyl acetate, hydroxystyrene, p-chlorostyrene, divinylbenzene, and other styrenes; and 3-phenylpropylene, 4-phenylpropylene, α-methylstyrene, etc. can coexist in the reaction system for polymerization. .

  The α-olefin having 3 to 20 carbon atoms is preferably an α-olefin having 4 or more carbon atoms, and particularly preferably an α-olefin having 4 to 8 carbon atoms. Examples of such α-olefins include 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, and 1-octene and the like are included, and one or more of these can be used in combination. Among these, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene are preferable from the viewpoint of availability and physical properties of the obtained copolymer. In the present invention, cyclic olefins having 3 to 20 carbon atoms, such as cyclopentene, cycloheptene, norbornene, 5-methyl-2-norbornene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, etc. You may use together.

  However, the comonomer species copolymerized with the ethylene polymer (A) and the comonomer species copolymerized with the ethylene / α-olefin copolymer (C) should not be the same species. This is because when the comonomer species copolymerized with the ethylene polymer (A) and the comonomer species copolymerized with the ethylene / α-olefin copolymer (C) are the same species, This is because the compatibility of the coalescence (A) and the ethylene / α-olefin copolymer (C) is improved, and the heat resistance of the ethylene resin composition tends to be lowered. However, as long as the heat resistance of the ethylene resin composition can be satisfied, the comonomer species copolymerized with the ethylene polymer (A) and the ethylene / α-olefin copolymer (C) are copolymerized. The comonomer species that are present may be the same species. Furthermore, the polymerization form of the ethylene / α-olefin copolymer (C) may be a random copolymer or a block copolymer.

  The structural unit derived from the α-olefin contained in the ethylene / α-olefin copolymer (C) is 9 to 22 mol%. Preferably it is 10-22 mol%, More preferably, it is 11-17 mol%. When the structural unit derived from the α-olefin contained in the ethylene / α-olefin copolymer (C) is less than 9 mol%, the tackiness cannot be improved and the adhesiveness tends not to be improved. If the structural unit derived from the α-olefin contained in the ethylene / α-olefin copolymer (C) is more than 22 mol%, the compatibility with the ethylene polymer (A) decreases, and bleeding to the sheet surface occurs. There is a tendency that out occurs and it becomes difficult to feed out the sheet. In addition, stickiness to the chill roll occurs during sheet forming, which tends to make sheet thickness control and sheet forming difficult.

The density of the ethylene · alpha-olefin copolymer (C) is less than 850 kg / ^{m 3} or more 895kg / ^{m 3.} Preferably it is 850-890 kg / m < ³ >, More preferably, it is 850-880 kg / m < ³ >. When the density of the ethylene / α-olefin copolymer (C) is more than 895 kg / m ³ , tackiness cannot be improved, adhesion is not improved, and flexibility is not imparted. When the density of the ethylene / α-olefin copolymer (C) is less than 850 kg / m ³ , the compatibility with the ethylene polymer (A) is lowered, bleed out to the sheet surface occurs, and the sheet is wound. It tends to be difficult to unwind the sheet from the take-up body. Further, stickiness to the chill roll and the embossing roll occurs during sheet forming, which tends to make sheet thickness control and sheet forming difficult. That is, when the density of the ethylene · alpha-olefin copolymer (C) is less than 850 kg / ^{m 3} or more 895kg / ^{m 3,} since poorly compatible ethylene-based polymer (A), the ethylene polymer (A ), The heat resistance of the ethylene-based resin composition can be maintained. Further, it is possible to control the thickness of the sheet and form the sheet without making it difficult to unwind the sheet from the wound body of the sheet or causing stickiness to the chill roll and the embossing roll at the time of forming the sheet.

  The melting peak based on DSC of the ethylene / α-olefin copolymer (C) is 85 ° C. or less or in a range where it is not substantially observed. Preferably it is 80 degrees C or less or the range which is not substantially observed, More preferably, it is 75 degrees C or less or the range which is not substantially observed. When the melting peak of the ethylene / α-olefin copolymer (C) exceeds 85 ° C., tackiness cannot be improved, and adhesiveness tends not to improve.

  The melt flow rate (MFR2) of the ethylene / α-olefin copolymer (C) measured at 190 ° C. and 2.16 kg load according to JIS K-6721 is 0.1 to 100 g / 10 min. It is a range. Preferably it is 0.1-80 g / 10min, More preferably, it is 0.5-80g / 10min, More preferably, it is 1.0-50g / 10min.

  When the MFR2 of the ethylene / α-olefin copolymer (C) is less than 0.1 g / 10 minutes, the fluidity of the ethylene-based resin composition containing the ethylene / α-olefin copolymer (C) decreases, Productivity during sheet extrusion is reduced. In addition, the scorch property of the resin composition (“scorch” means that the resin composition is crosslinked early during processing), and gelation is likely to occur. For this reason, the torque of an extruder rises and sheet molding may become difficult. Even if a sheet is obtained, the gel material generated in the extruder may cause irregularities on the surface of the sheet, resulting in poor appearance. In addition, when a voltage is applied, cracks are generated around the gel within the sheet, and the dielectric breakdown resistance is reduced. Furthermore, moisture permeability at the gel object interface is likely to occur, and moisture permeability is reduced. Moreover, since unevenness | corrugation generate | occur | produces on the sheet | seat surface, since the adhesiveness with glass, a thin film electrode, and a back sheet deteriorates at the time of the lamination process of a solar cell module, adhesion | attachment becomes inadequate, and adhesiveness also falls. On the other hand, when the MFR2 of the ethylene / α-olefin copolymer (C) exceeds 100 g / 10 minutes, the molecular weight is low, so adhesion to a roll surface such as a chill roll occurs, and peeling is required, so a sheet is formed with a uniform thickness. It becomes difficult. Furthermore, since there is no stiffness in the resin composition, it tends to be difficult to form a thick sheet of 0.3 mm or more.

  Further, the MFR10 / MFR2 which is the ratio of the melt flow rate (MFR10) and MFR2 measured at 190 ° C. and 10 kg load according to JIS K-6721 of the ethylene / α-olefin copolymer (C) is 5 It is in the range of 0.0 to 8.0. MFR10 / MFR2 is preferably 5.5 to 8.0, and more preferably 5.5 to 7.5. When MFR10 / MFR2 is less than 5.0, it is difficult to produce an ethylene / α-olefin copolymer (C). If MFR10 / MFR2 is more than 8.0, the low temperature characteristics tend to deteriorate.

  The molecular weight distribution Mw / Mn, which is the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the ethylene / α-olefin copolymer (C) measured by gel permeation chromatography (GPC), is 1 The range is from 2 to 3.5. Mw / Mn is preferably 1.5 to 3.5, and more preferably 1.7 to 3.2. In order to produce an ethylene / α-olefin copolymer (C) having an Mw / Mn of less than 1.2, the ethylene / α-olefin copolymer must be polymerized by living polymerization. For this reason, catalyst activity cannot be obtained, or separation of low molecular weight and high molecular weight components of an ethylene / α-olefin copolymer obtained by a conventionally known polymerization method is required, resulting in an increase in production cost. Moreover, since the temperature range which can be shape | molded is narrow and the discharge amount with an extruder becomes non-uniform | heterogenous, it is difficult to obtain a sheet | seat of uniform thickness. When the Mw / Mn of the ethylene / α-olefin copolymer (C) is more than 3.5, the sheet has a low molecular weight component, so that the sheet is sticky, the sheet is blocked and the sheet is hardly fed out. In general, it is known that when the molecular weight distribution Mw / Mn is increased, the composition distribution is also widened, and the sheet becomes sticky. For this reason, a sheet | seat blocks and it becomes difficult to pay out a sheet | seat. Furthermore, since the low molecular weight component bleeds to the sheet surface, the adhesion is inhibited and the adhesiveness is lowered.

  The blending amount of the ethylene / α-olefin copolymer (C) is, by weight, ethylene polymer (A) / ethylene / α-olefin copolymer (C) = 100/0 to 10/90. Preferably, ethylene-based polymer (A) / ethylene / α-olefin copolymer = 100/0 to 20/80, more preferably ethylene-based polymer (A) / ethylene / α-olefin copolymer = 100. / 0 to 40/60, more preferably ethylene polymer (A) / ethylene / α-olefin copolymer = 100/0 to 60/40.

  When the weight ratio of the ethylene / α-olefin copolymer (C) is more than 90, the heat resistance of the sealing material is lowered. For this reason, when power is generated by sunlight in a state where the solar cell module is tilted, the glass and the electrodes gradually slide, and the glass tends to slide down. Further, stickiness to the chill roll and the embossing roll occurs during sheet forming, and the sheet thickness control and sheet forming tend to be difficult. Furthermore, sheet blocking occurs, making it difficult to unwind the sheet from the sheet winding body. By blending the ethylene / α-olefin copolymer (C) in the above range, the tackiness of the ethylene-based resin composition is improved, and each adherend, particularly polyester resin, steel plate, plastic plate, FRP plate, etc. It exists in the tendency which improves adhesiveness with the back surface protection member for solar cell modules.

[Method for producing ethylene / α-olefin copolymer (C)]
The production method of the ethylene / α-olefin copolymer (C) of the present invention is not particularly limited, and can be produced using various catalysts such as a titanium compound, a vanadium compound, or a metallocene compound. Among these, it is preferable to use a metallocene compound that makes it easy to obtain an ethylene / α-olefin copolymer satisfying the molecular weight distribution Mw / Mn and the composition distribution. 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. Moreover, as long as it is an ethylene polymer satisfying the requirements of a) to e), a metallocene compound having a structure different from that of the metallocene compound described in the patent document may be used. Two or more metallocene compounds may be blended and used. Furthermore, the aspect of the preferable manufacturing method of ethylene-alpha-olefin copolymer (C) is, for example,
(I) a conventionally known metallocene compound;
(II) selected from the group consisting of (II-1) an organoaluminum oxy compound, (II-2) a compound that reacts with the metallocene compound (I) to form an ion pair, and (II-3) an organoaluminum compound. At least one compound (sometimes called a cocatalyst);
In the presence of an olefin polymerization catalyst comprising, ethylene and one or two or more α-olefins having 3 to 20 carbon atoms may be copolymerized. (II-1) an organoaluminum oxy compound, (II-2) a compound that reacts with the metallocene compound (I) to form an ion pair, and (II-3) the organoaluminum compound comprises the ethylene polymer (A The thing similar to what was described in the location of the manufacturing method of () can be used. 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.

[polymerization]
The ethylene / α-olefin copolymer (C) of the present invention can be obtained by any of a conventionally known gas phase polymerization method or a liquid phase polymerization method such as a slurry polymerization method or a solution polymerization method. The ethylene / α-olefin copolymer (C) is preferably obtained by a liquid phase polymerization method such as a solution polymerization method.

When the above metallocene compound is used to copolymerize ethylene and an α-olefin having 3 to 20 carbon atoms to produce an ethylene / α-olefin copolymer (C), the metallocene compound (I) is The reaction volume is 10 ⁻⁹ to 10 ⁻¹ mol, preferably 10 ⁻⁸ to 10 ⁻² mol per liter of reaction volume.

  In the compound (II-1), the molar ratio [(II-1) / M] of the compound (II-1) and all transition metal atoms (M) in the metallocene compound (I) is preferably 1 to 10,000. Is used in an amount of 10 to 5000. Compound (II-2) has a molar ratio [(II-2) / M] to all transition metals (M) in metallocene compound (I) of 0.5 to 50, preferably 1 to 20. Used in various amounts. Compound (II-3) is used in an amount of 0 to 5 mmol, preferably 0 to 2 mmol, per liter of polymerization volume.

  In the solution polymerization according to the present invention, by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms in the presence of the metallocene compound as described above, the comonomer content is high, the composition distribution is narrow, and the molecular weight. An ethylene / α-olefin copolymer (C) having a narrow distribution can be produced efficiently. Here, the charged molar ratio of ethylene and the α-olefin having 3 to 20 carbon atoms is ethylene: α-olefin = 10: 90 to 99.9: 0.1, preferably ethylene: α-olefin = 30:70 to 99.9: 0.1, and more preferably ethylene: α-olefin = 50: 50 to 99.9: 0.1.

  Examples of the α-olefin having 3 to 20 carbon atoms include linear or branched α-olefins such as propylene, 1-butene, 2-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene and the like can be mentioned. The α-olefin used in the solution polymerization in the present invention includes polar group-containing olefins.

  Examples of polar group-containing olefins include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, maleic anhydride, and metal salts such as sodium salts thereof; methyl acrylate, ethyl acrylate, Α, β-unsaturated carboxylic esters such as n-propyl acrylate, methyl methacrylate and ethyl methacrylate; vinyl esters such as vinyl acetate and vinyl propionate; unsaturated glycidyl such as glycidyl acrylate and glycidyl methacrylate And the like. Vinylcyclohexane, diene or polyene; aromatic vinyl compounds such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o, p-dimethylstyrene, methoxystyrene, vinylbenzoic acid, methyl vinylbenzoate Styrenes such as vinyl benzyl acetate, hydroxystyrene, p-chlorostyrene, divinylbenzene; and 3-phenylpropylene, 4-phenylpropylene, α-methylstyrene, etc. may be allowed to coexist in the reaction system to proceed with high-temperature solution polymerization. Is possible.

Among these α-olefins, 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene are preferable. In the solution polymerization method of the present invention, cyclic olefins having 3 to 20 carbon atoms such as cyclopentene, cycloheptene, norbornene, 5-methyl-2-norbornene, 5-ethylidene-2-norbornene, and 5-vinyl- 2-norbornene or the like may be used in combination.
The ethylene / α-olefin copolymer (C) used in the present invention may be modified with an ethylenically unsaturated silane compound (B ′). Although it does not restrict | limit especially as an ethylenically unsaturated silane compound, It is preferable to use at least 1 sort (s) chosen from (B1) vinyltrimethoxysilane or 3-acryloxypropyltrimethoxysilane, and (B2) vinyltriethoxysilane.

The amount of the ethylenically unsaturated silane compound is preferably 0.6 to 3.0 parts by weight as the total of (B1) and (B2) with respect to 100 parts by weight of the ethylene polymer (C). 1.0 to 2.5 is more preferable. When the sum of (B1) and (B2) is in the above range, it is preferable in terms of high-speed adhesiveness.
The blending amount of the ethylenically unsaturated silane compound is preferably 0.5 to 1.5 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin copolymer (C). Similarly, the blending amount of (B2) is preferably 0.1 to 1.5 parts by weight. When the blending amount of (B1) and (B2) is in the above range, it is preferable in terms of storage stability.

  “Solution polymerization” according to the present invention is a general term for a method of performing polymerization in a state where a polymer is dissolved in an inert hydrocarbon solvent described later. The polymerization temperature in the solution polymerization according to the present invention is 0 to 200 ° C, preferably 20 to 190 ° C, and more preferably 40 to 180 ° C.

  In the solution polymerization according to the present invention, 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. Furthermore, an ethylene / α-olefin copolymer ( The amount of double bonds at the molecular ends of C) decreases. 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. Furthermore, the amount of double bonds at the molecular ends of the ethylene / α-olefin copolymer increases. However, when the polymerization temperature exceeds 200 ° C., the polymerization activity is extremely lowered, and thus it is not practical in terms of productivity.

  The polymerization pressure is a normal pressure to 10 MPa gauge pressure, preferably a normal pressure to 8 MPa gauge pressure. Copolymerization can be carried out in any of batch, semi-continuous and continuous methods. The reaction time (average residence time when the copolymerization reaction is carried out in a continuous process) varies depending on conditions such as the catalyst concentration and polymerization temperature, and can be appropriately selected, but is 1 minute to 3 hours, preferably 10 minutes to 2.5 hours. Furthermore, the polymerization can be carried out in two or more stages having different reaction conditions.

  The molecular weight of the obtained ethylene / α-olefin copolymer (C) can also be adjusted by changing the hydrogen concentration or polymerization temperature in the polymerization system within the scope of the present invention. Further, it can be adjusted by the amount of the compound (II) used. When hydrogen is added, the amount is suitably about 0.001 to 5,000 NL per 1 kg of the ethylene / α-olefin copolymer (C) to be produced. The number of vinyl groups and vinylidene groups present at the molecular ends of the resulting ethylene / α-olefin copolymer (C) can be adjusted by increasing the polymerization temperature and decreasing the amount of hydrogenation as much as possible.

When the ethylene / α-olefin polymer (C) is obtained by coordination polymerization as in the examples described later, the long-chain branched structure in the ethylene / α-olefin polymer (C) is ethylene / α-olefin. In the process of copolymerization, it is considered that a molecular chain (macromonomer) having a terminal vinyl group generated by a β-hydrogen elimination reaction is generated by reinsertion into the copolymer chain. Therefore, MFR10 / MFR2 in the ethylene / α-olefin copolymer can be controlled by increasing / decreasing the ratio ([macromonomer] / [ethylene]) between the macromonomer concentration and the ethylene concentration in the solution. . Generally, when [macromonomer] / [ethylene] is high, the amount of long chain branching in the ethylene / α-olefin copolymer increases, and when [macromonomer] / [ethylene] is low, ethylene • α- The amount of long chain branching in the olefin copolymer decreases.
Specific methods for increasing / decreasing [macromonomer] / [ethylene] in the solution include the following methods.

[1] Polymerization temperature The lower the polymerization temperature, the less likely the β-hydrogen elimination reaction occurs. Therefore, if the polymerization temperature is lowered, [macromonomer] / [ethylene] is decreased, and MFR10 / MFR2 in the ethylene / α-olefin copolymer is decreased.

[2] Polymer concentration If the polymer concentration in the solution is lowered, the macromonomer concentration is also relatively lowered. Therefore, [macromonomer] / [ethylene] is reduced, and MFR10 / in the ethylene / α-olefin copolymer is reduced. MFR2 decreases.

[3] Ethylene conversion ratio If the ethylene conversion ratio is lowered, the ethylene concentration in the solution increases, so [macromonomer] / [ethylene] decreases, and MFR10 / MFR2 in the ethylene / α-olefin copolymer becomes descend.

[4] Solvent type When the polymerization solvent is a high-boiling solvent, the ethylene concentration in the solution increases, so [macromonomer] / [ethylene] decreases, and MFR10 / MFR2 in the ethylene / α-olefin copolymer. Will decline.
In addition to controlling the β-hydrogen elimination reaction, the [macromonomer] / [ethylene]) is increased or decreased by controlling the chain transfer reaction to the Al atom, etc., in the ethylene / α-olefin copolymer. It is also possible to change MFR10 / MFR2.

  The solvent used in the solution polymerization according to the present invention is usually an inert hydrocarbon solvent, preferably a saturated hydrocarbon having a boiling point of 50 ° C. to 200 ° C. under normal pressure. Specific examples include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane, and kerosene; and alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane. Aromatic hydrocarbons such as benzene, toluene and xylene, and halogenated hydrocarbons such as ethylene chloride, chlorobenzene and dichloromethane are also included in the “inert hydrocarbon solvent” related to the high-temperature solution polymerization of the present invention. There is no limit. As described above, in the solution polymerization according to the present invention, not only the conventionally used aromatic hydrocarbon-soluble organoaluminum oxy compounds, but also MMAO, which is dissolved in aliphatic hydrocarbons and alicyclic hydrocarbons, A modified methylaluminoxane such as TMAO-341 (manufactured by Tosoh Finechem Co., Ltd.) can be used. As a result, if aliphatic hydrocarbons or alicyclic hydrocarbons are used as the solvent for solution polymerization, there is almost no possibility that aromatic hydrocarbons are mixed in the polymerization system or in the ethylene / α-olefin copolymer produced. It became possible to eliminate completely. That is, the solution polymerization method according to the present invention has a feature that the environmental load can be reduced and the influence on human health can be minimized.

  In order to suppress variations in physical property values, the ethylene / α-olefin copolymer (C) obtained by the polymerization reaction and other components added as required are melted, kneaded, granulated, etc. by any method. It is preferable.

Total density of the resin component of the ethylene-based polymer (A) and the ethylene · alpha-olefin copolymer (C) and the post-blending is preferably 855~940kg / ^{m 3,} in 870~940kg / ^{m 3} More preferably, it is more preferably 870 to 930 kg / m ³ , and particularly preferably 880 to 920 kg / m ³ . When the total density of the resin components after blending the ethylene polymer (A) and the ethylene / α-olefin copolymer (C) is less than 855 kg / m ³ , the sticking to the chill roll and the emboss roll at the time of forming the sheet is reduced. It tends to occur and sheet thickness control and sheet molding become difficult. Furthermore, sheet blocking occurs, and the sheet tends to be hardly unwound from the sheet winding body. On the other hand, if the total density of the resin components after blending the ethylene polymer (A) and the ethylene / α-olefin copolymer (C) is more than 940 kg / m ³ , the flexibility of the sealing material is reduced, When the module is laminated, the crystal cell is easily broken or the silver electrode is peeled off. Moreover, it is necessary to raise the temperature at the time of laminate molding.

[Organic peroxide]
The organic peroxide used in the present invention is obtained by graft-modifying an ethylene-based polymer (A) and an ethylene / α-olefin copolymer (C) used as necessary with an ethylenically unsaturated silane compound (B). It is used as a radical initiator.
By graft-modifying the ethylenically unsaturated silane compound (B) to the ethylene polymer (A) or the ethylene / α-olefin copolymer (C), the ethylene polymer (A) or the ethylene / α-olefin is grafted. A silane-modified polymer of copolymer (C) can be obtained. This silane-modified polymer can express a strong adhesive force.

  The organic peroxide preferably used in the present invention is capable of graft-modifying an ethylenically unsaturated silane compound (B) to an ethylene polymer (A) or an ethylene / α-olefin copolymer (C). There are no particular restrictions on the type. Preferable specific examples of the organic peroxide include dilauroyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, dibenzoyl peroxide, cyclohexanone peroxide, di-t- Butyl perphthalate, cumene hydroperoxide, t-butyl hydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexene, 2,5-dimethyl-2,5-di (t- Butyl peroxy) hexane, t-amylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxymaleic acid, 1 , 1-di (t-amylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (t-amino) Peroxy) cyclohexane, t-amylperoxyisononanoate, t-amylperoxynormal octoate, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di ( t-butylperoxy) cyclohexane, t-butylperoxyisopropyl carbonate, t-butylperoxy-2-ethylhexyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-amyl-par Oxybenzoate, t-butylperoxyacetate, t-butylperoxyisononanoate, t-butylperoxybenzoate, 2,2-di (butylperoxy) butane, n-butyl-4,4-di (t- Butyl peroxy) petitate, methyl ethyl ketone peroxide, Til 3,3-di (t-butylperoxy) butyrate, dicumyl peroxide, t-butyl cumyl peroxide, t-butyl peroxybenzoate, di-t-butyl peroxide, 1,1,3,3-tetrala Examples thereof include methylbutyl hydroperoxide and acetylacetone peroxide. Of these, 2,5-dimethyl-2,5-di (t-butylperoxy) hexene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylper Examples thereof include oxy-2-ethylhexyl carbonate and t-butyl peroxybenzoate.

  The compounding amount of the organic peroxide is 0 to 1 with respect to 100 parts by weight of the ethylene polymer (A) or 100 parts by weight of the total of the ethylene polymer (A) and the ethylene / α-olefin copolymer (C). 0.0 part by weight, preferably 0.01 to 0.5 part by weight. When the blending amount of the organic peroxide is within the above range, the gel fraction of the silane-modified polymer of the obtained ethylene polymer (A) can be suppressed. When the gel fraction becomes high, irregularities occur on the surface of the obtained sheet or the like, and the appearance deteriorates. Further, when a voltage is applied, cracks are generated around the gel inside the sheet or the like, and the dielectric breakdown resistance is lowered. Furthermore, when the gel fraction is high, moisture permeability at the gel interface is likely to occur, and moisture permeability is reduced.

[Method for producing modified polymer of ethylene polymer (A) and ethylene / α-olefin copolymer (C)]
A modified polymer obtained by modifying an ethylene polymer (A) with an ethylenically unsaturated silane compound (B), and an ethylene / α-olefin copolymer (C) with an ethylenically unsaturated silane compound (B) As a method for producing a modified polymer obtained by modification, a conventionally known modification method such as an extrusion melt modification method or a solution modification method can be used. Among these, the extrusion melt modification method is preferable because the production cost is low.

As the extrusion melt modification method in the present invention,
(I) a method of extrusion-melt modification in the presence of an ethylene polymer (A) powder, an ethylenically unsaturated silane compound (B), and an organic peroxide;
(Ii) a method of extrusion-melting modification in the presence of an ethylene polymer (A) powder, an ethylene polymer (A) pellet, an ethylenically unsaturated silane compound (B), and an organic peroxide;
(Iii) Extrusion melting modification by mixing an ethylene polymer (A) powder previously impregnated with an ethylenically unsaturated silane compound (B) and an organic peroxide and an ethylene polymer (A) pellet. And the like. In the extrusion melt modification methods (i) to (iii), an ethylene / α-olefin copolymer (C) may be further mixed into the ethylene polymer (A) as necessary.

  In the above (ii) and (iii), the weight ratio of the ethylene polymer (A) powder and the ethylene polymer (A) pellets is preferably a powder / pellet ratio of 100/0 to 1/99. Is 100/0 to 5/95, more preferably 100/0 to 20/80.

  In the present invention, the ethylene polymer (A) powder is one having a particle size of about 20 μm to 5 mm, preferably 0.05 to 4 mm as measured by optical microscope observation, laser diffraction scattering method or the like. Say something. When the particle diameter is less than 20 μm, blocking between particles in the extruder hopper occurs, causing poor biting into the extruder screw, and tends to cause uneven thickness of the sheet. When the particle diameter exceeds 5 mm, the history of polymer particles remains in the sheet, and unevenness and uneven thickness on the sheet surface tend to occur.

  In the present invention, the pellets of the ethylene polymer (A) are prepared using a known single-screw extruder, twin-screw extruder, or the like. Such pellets include round pellets, square pellets and the like. The size of the pellet depends on the size of the extruder hopper opening, but in the case of a normal extruder, the longest diameter of the pellet is preferably 5 cm or less. When the longest diameter of the pellet exceeds 5 cm, a history due to the pellet shape remains in the sheet, and unevenness and uneven thickness on the sheet surface tend to occur.

  When extrusion melt modification is performed in a state where powders of ethylene polymer (A) are mixed, liquid additives such as organic peroxides and ethylenically unsaturated silane compounds (B) are powdered when various additives are blended. Easy to impregnate. For this reason, since density nonuniformity does not generate | occur | produce in an ethylene resin composition, the solar cell sealing material containing the said ethylene resin composition, and the solar cell sealing sheet, it is preferable. In addition, various additives are uniformly dispersed during extrusion. For this reason, generation | occurrence | production of the gel in an ethylene-type resin composition, the solar cell sealing material containing the said ethylene-type resin composition, and the sealing sheet for solar cells is prevented, and the improvement of adhesiveness and the dielectric breakdown voltage can be aimed at. . In addition, by impregnating the ethylenic unsaturated silane compound (B) in the powder of the ethylene polymer (A), even when the pellets of the ethylene polymer (A) are used at the same time, the compatibility between the powder and the pellets The effect equivalent to the case of using the ethylene polymer (A) powder alone can be obtained.

  The amount of the organic peroxide and the ethylenically unsaturated silane compound (B) to 100 parts by weight of the total amount of the powder and pellets of the ethylene polymer (A) in the extrusion melt modification is 0 to 1. 0 part by weight, 0.1 to 5 parts by weight of ethylenically unsaturated silane compound (B), preferably 0.01 to 0.5 part by weight of organic peroxide, ethylenically unsaturated silane compound (B) Is 0.1 to 4 parts by weight. In addition, when obtaining the ethylene-type resin composition which further contains the modified polymer of an ethylene-alpha-olefin copolymer (C), the weight part of the said ethylene-type polymer (A) is ethylene-type polymer (A ) And ethylene / α-olefin copolymer (C) in total parts by weight.

  In the extrusion melt modification method, an ethylene polymer (A) and, if necessary, an ethylene / α-olefin copolymer (C) and an ethylenically unsaturated silane compound (B) are reacted to obtain a modified polymer. Extrusion is performed using a conventionally known single-screw extruder, twin-screw extruder, or the like. The extrusion conditions at this time are usually at least the melting point of the ethylene polymer (A), specifically, when the ethylene polymer (A) is modified, for example, 100 to 300 ° C., preferably 150 to 260 ° C. For 0.5 to 10 minutes.

  In addition, when the radically polymerizable ethylenically unsaturated silane compound (B) is graft-modified to the ethylene polymer (A) and, if necessary, the ethylene / α-olefin copolymer (C), the reducing property is reduced. Substances may be added. When the reducing substance is used, the graft amount of the radical polymerizable ethylenically unsaturated silane compound (B) can be improved.

[Ultraviolet absorber (D), light stabilizer (E), heat stabilizer (F)]
The ethylene-based resin composition of the present invention may contain at least one additive selected from the group consisting of an ultraviolet absorber (D), a light stabilizer (E), and a heat resistance stabilizer (F). The compounding quantity of the said additive is 0.005-5 weight part with respect to a total of 100 weight part of ethylene-type polymer (A) and the ethylene-alpha-olefin copolymer (C) as needed. It is preferable. Furthermore, it is preferable to contain at least two types of additives selected from the above three types, and it is most preferable that all the three types are contained. When the blending amount of the above additive is in the above range, the effect of improving the weather resistance stability and heat resistance stability is sufficiently secured, and the transparency of the ethylene-based resin composition and the deterioration of the adhesion to glass are prevented. This is preferable.

  Specific examples of the ultraviolet absorber (D) include 2-hydroxy-4methoxybenzophenone, 2-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4-carboxybenzophenone, 2-hydroxy-4- Benzophenones such as N-octoxybenzophenone, benzotriazol such as 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, 2- (2-hydroxy-5-methylphenyl) benzotriazole And salicylic acid ester type compounds such as phenyl salicylate and p-octylphenyl salicylate are used.

  Specific examples of the light stabilizer (E) include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, poly [{6- (1,1,3,3-tetramethylbutyl) amino. -1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4 Hindered amine compounds such as -piperidyl) imino}] and hindered piperidine compounds are preferably used.

  Specific examples of the heat stabilizer (F) include tris (2,4-di-tert-butylphenyl) phosphite and bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl. Ester phosphorous acid, tetrakis (2,4-di-tert-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite, and bis (2,4-di-tert-butyl) Phosphite heat stabilizers such as phenyl) pentaerythritol diphosphite, lactone heat resistance stabilizers such as the reaction product of 3-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene Agent, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(methylene-2,4,6-triyl) tri-p-cresol, 1 , 3, 5 Trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxyphenyl) benzylbenzene, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and the like Hindered phenol heat stabilizers, sulfur heat stabilizers, amine heat stabilizers, etc. In addition, one or more of these can be used, and among them, phosphite heat stabilizer Agents and hindered phenol heat stabilizers are preferred.

[Other ingredients and additives]
The ethylene-based resin composition of the present invention may appropriately contain other resin components and additives other than the above-mentioned components within a range not impairing the object of the present invention.

Examples of other resin components include various polyolefins other than the ethylene-based polymer (A), such as ethylene / α-olefin copolymers having a density of less than 900 kg / m ³ , styrene-based or ethylene-based block copolymers, Examples include propylene-based polymers. These are 0.0001 parts per 100 parts by weight of the total amount of the ethylene polymer (A) or 100 parts by weight of the total amount of the ethylene polymer (A) and the ethylene / α-olefin copolymer (C). Parts by weight to 50 parts by weight, preferably 0.001 to 40 parts by weight.

  Examples of additives are selected from various resins other than polyolefin, various rubbers, plasticizers, fillers, pigments, dyes, antistatic agents, antibacterial agents, antifungal agents, flame retardants, crosslinking aids, dispersing agents, and the like. 1 type or 2 types or more of additives which are included, but it is not limited to these.

  As the crosslinking aid, conventionally known ones generally used for olefin resins can be used. Such a crosslinking aid is a compound having two or more double bonds in the molecule, and specifically includes t-butyl acrylate, lauryl acrylate, cetyl acrylate, stearyl acrylate, 2-methoxyethyl acrylate, ethyl carbyl. Monoacrylate such as tall acrylate, methoxytripropylene glycol acrylate, t-butyl methacrylate, lauryl methacrylate, cetyl methacrylate, stearyl methacrylate, methoxyethylene glycol methacrylate, monomethacrylate such as methoxypolyethylene glycol methacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, die Diacrylates such as lenglycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1,3-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1 , 9-nonanediol dimethacrylate neopentyl glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and other dimethacrylates, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, penta Tris such as erythritol triacrylate Trimethacrylates such as chlorate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetraacrylates such as pentaerythritol tetraacrylate, tetramethylolmethane tetraacrylate, divir aromatic compounds such as divinylbenzene, di-i-propenylbenzene, tri Examples include cyanurates such as allyl cyanurate and triallyl isocyanurate, triallyl compounds such as diallyl phthalate, diallyl compounds, oximes such as p-quinonedioxime and pp'-dibenzoylquinonedioxime, and maleimides such as phenylmaleimide. . Of these crosslinking aids, diacrylates, dimethacrylates, and divinyl aromatic compounds are more preferred.

  The amount of the crosslinking aid is 100 parts by weight of the total amount of the ethylene polymer (A) or 100 parts by weight of the total amount of the ethylene polymer (A) and the ethylene / α-olefin copolymer (C). 0 to 5 parts by weight is preferable. When the blending amount of the crosslinking aid is within such a range, the ethylene-based resin composition can have an appropriate crosslinked structure, and heat resistance, mechanical properties, and adhesiveness can be improved.

  The ethylene-based resin composition of the present invention comprises a modified polymer obtained by modifying an ethylene-based polymer (A) with an ethylenically unsaturated silane compound (B), and, if necessary, an ethylene / α-olefin copolymer (C). Modified with an ethylenically unsaturated silane compound (B). The total amount of grafted silanes derived from the ethylenically unsaturated silane compound (B) in this ethylene-based resin composition is 50 to 8000 ppm, preferably 100 to 7000 ppm, more preferably 640 to 2960 ppm, More preferably, it is 800-2960 ppm, Most preferably, it is 800-2800 ppm. If the amount of grafted silane is less than 50 ppm, the adhesive strength to glass, the back sheet and the thin film electrode; in particular, the adhesive strength to the back sheet is lowered. If the amount of grafted silane exceeds 8000 ppm, a large amount of ethylenically unsaturated silane compound (B) and organic peroxide is used to increase the amount of grafted silane. Adhesiveness to the surface is lowered, or the appearance of the solar cell encapsulant sheet is deteriorated.

The amount of graft silica graft-modified to the molecular chain of the ethylene polymer (A) and the ethylene / α-olefin copolymer (C) can be measured by the following procedure.
1) A sheet made of the ethylene resin composition of the present invention is Soxhlet extracted using acetone as a solvent to prepare a sheet sample. 2) The obtained sheet sample is wet-decomposed, and then it is measured by measuring the volume of silicon (Si) with an ICP emission analyzer (ICPS-8100, manufactured by Shimadzu Corp.) with pure water.

It is known that the alkoxysilyl group of the silane-modified resin is easily hydrolyzed into a silanol group in the presence of water, and the silanol group is easily condensed by heating to produce a siloxane group. Yes. That is, it is known that when water is present, an alkoxysilyl group involved in adhesion to a solar cell element or the like is consumed as a siloxane group, resulting in a decrease in adhesiveness.

  Furthermore, the ethylene-based resin composition of the present invention comprises a modified product obtained by modifying an ethylene-based polymer (A) with an ethylenically unsaturated silane compound (B), and an ethylene / α-olefin copolymer (C ) Modified with an ethylenically unsaturated silane compound (B) has a gel fraction of 30% or less. If the gel fraction is more than 30%, as described above, the adhesion to the adherend is lowered, or the appearance of the solar cell encapsulant sheet is deteriorated.

2. Solar cell encapsulant The ethylene-based resin composition of the present invention has adhesion to glass and a solar cell back surface protective member, weather resistance, heat resistance, volume resistivity, electrical insulation, moisture permeability, electrode corrosion, molding And is suitably used as a solar cell sealing material for a conventionally known solar cell module. In particular, an ethylene resin composition comprising a modified polymer of an ethylene polymer (A) having a density of 900 to 920 kg / m ³ and, if necessary, a modified polymer of an ethylene / α-olefin copolymer (C). Is excellent in transparency and flexibility, and can be suitably used for a crystalline solar cell module.

  The manufacturing method of the solar cell encapsulant of the present invention may be a normal method, and a method of melt blending the above-described components with a kneader, a roll, a Banbury mixer, an extruder, or the like is preferable.

[Seal sheet for solar cell]
One of preferable embodiments of the present invention is a solar cell encapsulant (solar cell encapsulating sheet) including a sheet (or layer) made of the ethylene-based resin composition of the present invention. As long as the solar cell encapsulating sheet has at least one sheet (or layer) made of the ethylene-based resin composition of the present invention, it may be combined with other layers.

  The thickness of the sheet (layer) made of the ethylene resin composition of the present invention is 0.01 mm to 2 mm, preferably 0.05 to 1 mm, more preferably 0.1 to 1 mm, and still more preferably. It is 0.15 mm-1 mm, More preferably, it is 0.2-1 mm, More preferably, it is 0.2-0.9 mm, More preferably, it is 0.3-0.9 mm, Most preferably, it is 0.00. 3 to 0.8 mm. When the thickness of the sheet (layer) made of the ethylene-based resin composition of the present invention is within this range, breakage of glass, solar cells, thin film electrodes, etc. in the laminating step can be suppressed. In addition, the solar cell module can be laminated at a low temperature. Furthermore, when the sheet | seat (layer) which consists of an ethylene-type resin composition of this invention has sufficient light transmittance, the solar cell module of a high photovoltaic power generation amount can be obtained.

  The method for forming a sheet (layer) made of the ethylene resin composition of the present invention is not particularly limited, but various known forming methods (cast molding, extrusion sheet molding, inflation molding, injection molding, compression molding, calendar molding). Etc.). For example, the ethylene-based polymer (A) and, if necessary, the ethylene / α-olefin copolymer (C) are extruded and modified with an ethylenically unsaturated silane compound (B) in an extruder, and ultraviolet rays are used. Extrusion sheet molding is performed while melt-kneading the absorbent (D), light stabilizer (E), heat stabilizer (F), and other additives as necessary. Thereby, the solar cell sealing material containing the sheet | seat which consists of an ethylene-type resin composition of this invention can be obtained.

When using two types of ethylene polymer (A), ethylene polymer (A-1) and ethylene polymer (A-2);
1) A modified polymer obtained by extrusion-melting an ethylene polymer (A-1) with an ethylenically unsaturated silane compound (B) in advance, an ethylene polymer (A-2), and various additives (D, E , F, etc.) and melt kneaded;
2) Various additives (D, E, F, etc.) and an ethylene polymer (A-2) previously melt-kneaded and an ethylene polymer (A-1) with an ethylenically unsaturated silane compound ( What was melt-kneaded with the modified polymer that was extrusion-melt modified in B);
3) A modified polymer obtained by extrusion-melting an ethylene polymer (A-1) with an ethylenically unsaturated silane compound (B) and various additives (D, E, F, etc.) previously melt-kneaded Melt-kneaded with ethylene polymer (A-2);
4) When the ethylene polymer (A-1) is extrusion-melt modified with the ethylenically unsaturated silane compound (B), various additives (D, E, F, etc.) are melt-kneaded, and ethylene heavy What knead | mixed kneading | mixing (A-2);
Can be obtained by extrusion sheet molding to obtain a solar cell encapsulant having a sheet (or layer) made of the ethylene resin composition of the present invention.

  The two types of ethylene polymer (A-1) and ethylene polymer (A-2) satisfy the requirements of a) to e) of the ethylene polymer (A) in the present invention. For example, they may be the same or different.

  As described above, the solar cell encapsulant having a storage elastic modulus and porosity in a specific range has an advantage that cell cracking and bubble entrainment can be prevented in laminating when manufacturing a solar cell module.

  Further, the sheet (or layer) made of the ethylene-based resin composition of the present invention may be a single-wafer type cut according to the size of the solar cell module, or matched to the size immediately before the production of the solar cell module. It may also be a roll form that can be cut.

  The sheet (or layer) comprising the ethylene resin composition of the present invention has an internal haze in the range of 1% to 60%, preferably 1% to 40% when measured with a sample having a thickness of 0.5 mm or less. Is desirable.

  The sealing sheet for solar cells should just have at least 1 sheet | seat (or layer) which consists of an ethylene-type resin composition of this invention. Therefore, the layer composed of the ethylene resin composition of the present invention may be one layer or two or more layers. From the viewpoint of simplifying the structure and reducing costs, and from the viewpoint of effectively utilizing light by minimizing interface reflection between layers, a single layer is preferable.

  The solar cell encapsulating sheet which is a preferred embodiment of the present invention may be composed only of a sheet (or layer) comprising the ethylene resin composition of the present invention, or from the ethylene resin composition of the present invention. It may have a layer (hereinafter also referred to as “other layer”) other than the sheet (or layer).

  Examples of other layers are, if classified according to purpose, hard coat layer for surface protection or back surface protection, adhesive layer, antireflection layer, gas barrier layer, antifouling layer, back sheet, back surface protection for solar cell module A member etc. can be provided. Examples of other layers are, if classified by material, layers made of ultraviolet curable resins, layers made of thermosetting resins, layers made of polyolefin resins, layers made of carboxylic acid-modified polyolefin resins, and fluorine-containing resins. A layer made of a cyclic olefin (co) polymer, a layer made of a polyester resin, a glass, a layer made of an inorganic compound, and the like. Preferably, a layer made of a polyolefin resin, a layer made of a carboxylic acid-modified polyolefin resin, a layer made of a fluorine-containing resin, a layer made of a cyclic olefin (co) polymer, a layer made of a polyester resin, or glass can be used.

  There is no restriction | limiting in particular in the positional relationship of the sheet | seat (or layer) which consists of an ethylene-type resin composition of this invention, and another layer, It selects suitably in the range with which the effect of this invention is acquired. That is, the other layers may be provided between two or more layers made of the ethylene resin composition of the present invention, may be provided in the outermost layer of the solar cell encapsulating sheet, or otherwise. It may be provided in the position. Other layers may be provided only on one side of the sheet (or layer) comprising the ethylene-based resin composition of the present invention, or other layers may be provided on both sides. There is no restriction | limiting in particular in the number of other layers, Arbitrary number can be provided and it is not necessary to provide another layer.

  The method for laminating the sheet (or layer) comprising the ethylene-based resin composition of the present invention and the other layers is not particularly limited, but includes a cast molding machine, an extrusion sheet molding machine, an inflation molding machine, an injection molding machine, and the like. A method of obtaining a laminate by co-extrusion using a known melt extruder; or a method of obtaining a laminate by melting or heating and laminating the other layer on one preformed layer is preferred.

  Also suitable adhesives (for example, maleic anhydride modified polyolefin resins (for example, Admer made by Mitsui Chemicals, Modic made by Mitsubishi Chemical), low (non) crystalline soft polymers such as unsaturated polyolefins, ethylene / Acrylic ester / maleic anhydride terpolymers (for example, Bondine manufactured by Sumika CDF Chemical Co., Ltd.), acrylic adhesives, ethylene / vinyl acetate copolymers or adhesive resin compositions containing these For example, a dry laminating method or a heat laminating method. As the adhesive, those having a heat resistance of about 120 ° C. to 150 ° C. are preferably used, and a polyester-based or polyurethane-based adhesive is exemplified as a suitable one. Moreover, in order to improve the adhesiveness of both layers, for example, a silane coupling treatment, a titanium coupling treatment, a corona treatment, a plasma treatment, or the like may be used.

  The solar cell encapsulating sheet of the present invention desirably has an internal haze in the range of 1% to 60%, preferably 5% to 50% when measured with a sample having a thickness of 0.5 mm or less.

[Solar cell module]
The solar cell encapsulant of the present invention and the solar cell encapsulating sheet which is a preferred embodiment thereof have the excellent characteristics as described above. Therefore, the solar cell module obtained using such a solar cell sealing material and / or sheet has the effects of the present invention.

  Examples of the solar cell module include a crystalline solar cell module in which solar cell elements formed of polycrystalline silicon or the like are usually sandwiched and stacked between solar cell sealing sheets, and both front and back surfaces are covered with protective sheets. That is, a typical solar cell module includes a solar cell module protective sheet (surface protective member) / solar cell encapsulating sheet / solar cell element / solar cell encapsulating sheet / solar cell module protective sheet (back surface protecting member). ). But the solar cell module which is one of the preferable embodiment of this invention is not limited to said structure, A part of said each layer is abbreviate | omitted suitably in the range which does not impair the objective of this invention, or the said Other layers can be provided as appropriate. Examples of the layer other than the above include, but are not limited to, an adhesive layer, a shock absorbing layer, a coating layer, an antireflection layer, a back surface rereflection layer, and a light diffusion layer. These layers are not particularly limited, but can be provided at appropriate positions in consideration of the purpose and characteristics of each layer.

The solar cell encapsulant of the present invention, the solar cell encapsulant sheet,
It can be used for 1) crystalline silicon solar cell modules and 2) thin film silicon (amorphous silicon) solar cell modules.

  Since the thin-film solar cell in the aspect 2) is thinner than the crystalline silicon solar cell in the aspect 1), the thin-film solar cell is pressurized during the manufacture of the solar cell module and the external impact during the module operation. It is hard to break by. For this reason, the softness | flexibility of the sealing sheet for solar cells used for a thin film solar cell module may be lower than what is used for a crystalline silicon type solar cell module. On the other hand, since the electrode of the thin film photovoltaic cell is a metal thin film layer as described above, the power generation efficiency may be significantly reduced when it is deteriorated by corrosion. Therefore, it is less flexible than an ethylene / vinyl acetate copolymer (EVA), but does not necessarily require a cross-linking agent as a generation source of decomposition gas, and includes a sheet made of the ethylene-based resin composition of the present invention. The sealing sheet is more suitably used as a solar cell sealing sheet for a thin film solar cell module in the aspect of 2).

As another solar cell module, there is a solar cell module using silicon for solar cells. Solar cell modules using silicon for solar cells include hybrid type (HIT type) solar cell modules in which crystalline silicon and amorphous silicon are laminated, and multi-junction type (tandem type) solar cells in which silicon layers having different absorption wavelength ranges are laminated. Examples thereof include a battery module, a spherical silicon solar cell module in which an infinite number of spherical silicon particles (diameter of about 1 mm) and a concave mirror having a diameter of 2 to 3 mm (also serving as an electrode) for increasing the light collecting ability are combined. Further, in a solar cell module using silicon for a solar cell, the role of an amorphous silicon type p-type window layer having a conventional pin junction structure is induced by “field effect” from “insulated transparent electrode”. A field effect solar cell module having a structure replaced with “inversion layer” may also be mentioned. Also, a GaAs-based solar cell module using single-crystal GaAs as a solar cell; I-III called a chalcopyrite system made of Cu, In, Ga, Al, Se, S or the like instead of silicon as a solar cell -CIS or CIGS (chalcopyrite) solar cell module using a group VI compound; CdTe-CdS solar cell using a Cd compound thin film as a solar cell, Cu ₂ ZnSnS ₄ (CZTS) solar cell module, etc. It is done. The solar cell encapsulant of the present invention can be used as a solar cell encapsulant for all these solar cell modules.

  The solar cell encapsulant of the present invention can be suitably used as a solar cell encapsulant on the back side of a crystalline solar cell module and a solar cell encapsulant of a thin film solar cell module that is vulnerable to moisture penetration.

[Surface protection member for solar cell module]
The surface protection member for the solar cell module used in the solar cell module is not particularly limited, but is located on the outermost layer of the solar cell module, so that the solar cell includes weather resistance, water repellency, contamination resistance, mechanical strength, etc. It is preferable to have performance for ensuring long-term reliability of the module in outdoor exposure. Moreover, in order to utilize sunlight effectively, it is preferable that it is a highly transparent sheet | seat with a small optical loss.

  As a material for the surface protection member for a solar cell module suitably used for the solar cell module, a resin film made of a polyester resin, a fluororesin, an acrylic resin, a cyclic olefin (co) polymer, an ethylene-vinyl acetate copolymer, or the like. And glass substrates. The resin film is preferably a polyester resin excellent in transparency, strength, cost and the like, particularly a polyethylene terephthalate resin, a fluorine resin having good weather resistance, and the like.

  Examples of fluororesins include tetrafluoroethylene-ethylene copolymer (ETFE), polyvinyl fluoride resin (PVF), polyvinylidene fluoride resin (PVDF), polytetrafluoroethylene resin (TFE), and tetrafluoroethylene. -There are a hexafluoropropylene copolymer (FEP) and a polytrifluoroethylene chloride (CTFE). Polyvinylidene fluoride resin is excellent in terms of weather resistance, but tetrafluoroethylene-ethylene copolymer is excellent in terms of both weather resistance and mechanical strength. Moreover, it is desirable to perform a corona treatment and a plasma treatment on the surface protection member in order to improve adhesion with a material constituting another layer such as a sealing material layer. It is also possible to use a sheet that has been subjected to stretching treatment for improving mechanical strength, for example, a biaxially stretched polypropylene sheet.

  When a glass substrate is used as the surface protection member for a solar cell module, the glass substrate preferably has a total light transmittance of 80% or more, more preferably 90% or more, of light having a wavelength of 350 to 1400 nm. As such a glass substrate, it is common to use white plate glass with little absorption in the infrared part, but even blue plate glass has little influence on the output characteristics of the solar cell module if the thickness is 3 mm or less. Further, tempered glass can be obtained by heat treatment to increase the mechanical strength of the glass substrate, but float plate glass without heat treatment may be used. Further, an antireflection coating may be provided on the light receiving surface side of the glass substrate in order to suppress reflection.

[Back side protection member for solar cell module]
The back surface protection member for the solar cell module used in the solar cell module is not particularly limited, but since it is located on the outermost layer of the solar cell module, various characteristics such as weather resistance, mechanical strength, etc., similar to the above surface protection member. Is required. Therefore, you may comprise the back surface protection member for solar cell modules with the material similar to a surface protection member. That is, the above-mentioned various materials used as the surface protection member can be used as the back surface protection member. In particular, a polyester resin and glass can be preferably used.

  Moreover, since a back surface protection member does not presuppose passage of sunlight, the transparency calculated | required by a surface protection member is not necessarily requested | required. Therefore, a reinforcing plate may be attached to increase the mechanical strength of the solar cell module or to prevent distortion and warpage due to temperature change. As the reinforcing plate, for example, a steel plate, a plastic plate, an FRP (glass fiber reinforced plastic) plate or the like can be preferably used.

  Furthermore, the solar cell sealing material of this invention may be integrated with the said back surface protection member for solar cell modules. By integrating the solar cell sealing material of the present invention and the solar cell module back surface protection member, the process of cutting the solar cell sealing material and the solar cell module back surface protection member into a module size at the time of module assembly can be shortened. . Moreover, the layup process can also be shortened and abbreviate | omitted by making the process of laying up a solar cell sealing material and the back surface protection member for solar cell modules into the process of laying up with the integrated sheet | seat.

  The method for laminating the solar cell sealing material and the solar cell module back surface protective member in the case of integrating the solar cell sealing material and the solar cell module back surface protective member of the present invention is not particularly limited. The lamination method includes a method of obtaining a laminate by co-extrusion using a known melt extruder such as a cast molding machine, an extrusion sheet molding machine, an inflation molding machine, an injection molding machine, or the like; A method of obtaining a laminate by melting or heat laminating the other layer is preferred.

  Also suitable adhesives (for example, maleic anhydride modified polyolefin resins (for example, Admer made by Mitsui Chemicals, Modic made by Mitsubishi Chemical), low (non) crystalline soft polymers such as unsaturated polyolefins, ethylene / Acrylic ester / maleic anhydride terpolymers (for example, Bondine manufactured by Sumika CDF Chemical Co., Ltd.), acrylic adhesives, ethylene / vinyl acetate copolymers or adhesive resin compositions containing these For example, a dry laminating method or a heat laminating method.

  As the adhesive, those having a heat resistance of about 120 ° C. to 150 ° C. are preferable, and specifically, polyester-based or polyurethane-based adhesives are preferable. In order to improve the adhesion between the two layers, at least one layer may be subjected to, for example, a silane coupling treatment, a titanium coupling treatment, a corona treatment, a plasma treatment, or the like.

[Solar cell element]
The solar cell element in the solar cell module is not particularly limited as long as it can generate power using the photovoltaic effect of the semiconductor. Solar cell elements include, for example, silicon (single crystal, polycrystalline, amorphous) solar cells, compound semiconductors (III-III, II-VI, etc.) solar cells, wet solar cells, organic A semiconductor solar cell or the like can be used. Among these, a polycrystalline silicon solar cell is preferable from the viewpoint of balance between power generation performance and cost.

  Both silicon solar cell elements and compound semiconductor solar cell elements have excellent characteristics as solar cell elements, but are known to be easily damaged by external stress, impact, and the like. Since the solar cell sealing material of the present invention is excellent in flexibility, it has a great effect of absorbing stress, impact, etc. on the solar cell element and preventing damage to the solar cell element. Therefore, in the solar cell module of the present invention, it is desirable that the layer made of the solar cell sealing material of the present invention is directly joined to the solar cell element.

  In addition, when the solar cell encapsulant has thermoplasticity, the solar cell element can be taken out relatively easily even after the solar cell module is once produced. Yes. Since the ethylene-based resin composition that is an essential component of the solar cell encapsulant of the present invention has thermoplasticity, the entire solar cell encapsulant has thermoplasticity, which is also preferable from the viewpoint of recyclability.

[electrode]
Although the structure and material of the electrode in a solar cell module are not specifically limited, In a specific example, it has a laminated structure of a transparent conductive film and a metal film. The transparent conductive film is made of SnO ₂ , ITO, ZnO or the like. The metal film is made of a metal such as silver, gold, copper, tin, aluminum, cadmium, zinc, mercury, chromium, molybdenum, tungsten, nickel, and vanadium. These metal films may be used alone or as a composite alloy. The transparent conductive film and the metal film are formed by a method such as CVD, sputtering, or vapor deposition.

[Power generation equipment]
The solar cell module which is a preferred embodiment of the present invention is excellent in productivity, power generation efficiency, life and the like. For this reason, the power generation equipment using such a solar cell module is excellent in cost, power generation efficiency, life, etc., and has a high practical value.

  The above power generation equipment can be used for a long period of time, whether outdoors or indoors, such as being installed on the roof of a house, used as a mobile power source for outdoor use such as camping, or used as an auxiliary power source for an automobile battery.

  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.

[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. For 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]
Similarly, 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.

[Synthesis of Ethylene Polymer (A)]
[Polymerization example] Ethylene polymer (A) 1
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 0.015 mg atom in terms of zirconium atom were added to the prepolymerized catalyst prepared as described above.
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 completion of the polymerization, the polymer was filtered and dried at 80 ° C. overnight to obtain 105 g of ethylene polymer (A) 1.

The ethylene polymer (A) 1 obtained by repeating the above polymerization was subjected to a die temperature = 190 ° C. with a single screw extruder (screw diameter 20 mmφ · L / D = 28) manufactured by Thermo Plastic Co., Ltd. Thus, an ethylene polymer (A) 1 which is a pellet of the ethylene polymer (A) 1 was obtained. The physical properties of (A) 1 are shown below.
Density measured by density gradient tube method = 903 kg / m 3, melting peak temperature measured by DSC is 98 ° C., MFR measured at 190 ° C. and 2.16 kg load according to JIS K-6721 is 3.8 [G / 10min], Mw / Mn measured using GPC was 2.1, and the metal residue determined by ICP emission analysis was 10 ppm.

[Example 1]
100 parts by weight of the ethylene polymer (A) obtained in the polymerization example, 1.4 parts by weight of vinylmethoxysilane as the ethylenically unsaturated silane compound (B1), and as the ethylenically unsaturated silane compound (B2) 0.6 parts by weight of vinylethoxysilane, 0.05 parts by weight of 2,5-dimethyl-2,5-di (t-butylperoxy) hexane as the organic peroxide 1, and an ultraviolet absorber (D) 0.4 parts by weight of 2-hydroxy-4-normal-octyloxybenzophenone as 0.1 wt. Of bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate as radical scavenger (E) And 0.1 parts by weight of tris (2,4-di-tert-butylphenyl) phosphite as a heat stabilizer (F) are added and further dry blended, To obtain a blend of the body.

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 x 0.8 mm) and extrusion at a die temperature of 210 ° C, cooling at a roll temperature of 30 ° C, and then using an embossing roll 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 polymer which modified | denatured the ethylene-type polymer (A) with the ethylenically unsaturated silane compound (B) was obtained. The maximum thickness t _{max of the} sheet was 500 μm.

The obtained sheet was evaluated for the following characteristics. The results are shown in Table 4.
(MFR)
Measured according to JIS K-6721 at 190 ° C. and 2.16 kg load (graft silane amount)
The obtained sheet (sheet made of an ethylene resin composition) was subjected to Soxhlet extraction using acetone as a solvent. The obtained sheet sample was wet-decomposed and then made up with pure water, and silicon (Si) was quantified with an ICP emission analyzer (ICPS-8100, manufactured by Shimadzu Corporation).

(Adhesive strength)
A sheet sample having a thickness of 0.3 mm was sandwiched between an ozone-cleaned product of a back sheet made of polyethylene terephthalate resin (manufactured by Lintec Co., Ltd., repnea) and a glass plate. This was placed on a hot plate adjusted to 150 ° C. in a vacuum laminator, depressurized for 3 minutes, and then heated for 5 minutes. Thereby, a laminate of glass / sheet sample / back sheet was produced.
This laminate was cut into a width of 10 mm, and the peel strength of the sheet sample with respect to each adherend (back sheet, glass) by 180 ° peel 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. "

(Storage test)
A sheet sample of a solar cell encapsulant having a thickness of 300 μm, which was embossed on one side, was prepared. This sheet sample was put in a polyethylene plastic bag having a thickness of 100 μm, and the opening of the plastic bag was heat sealed and stored at 40 ° C. and 90% for 2 weeks. A laminated body of glass / sheet sample / back sheet was prepared using the sheet sample after storage. The peel strength of this laminate from the back sheet of the sheet sample was measured by 180 degree peel. Moreover, MFR was measured using the sheet | seat sample after storage.

[Example 2]
As in Example 1, except that 1.0 part by weight of vinylmethoxysilane was used as the ethylenically unsaturated silane compound (B1) and 1.0 part by weight of vinylethoxysilane was used as the ethylenically unsaturated silane compound (B2). Thus, a blend was obtained, and a sheet was further obtained. The obtained sheet was evaluated. The results are shown in the table.

  In Examples 1 and 2, no significant decrease in MFR was observed after the storage test, sufficient fluidity was obtained, and sufficient adhesion to the back sheet was maintained even during lamination.

[Comparative Example 1]
A blend was obtained in the same manner as in Example 1 except that vinylmethoxysilane was replaced by 1.8 parts by weight as the ethylenically unsaturated silane compound (B1), and a sheet was further obtained. The obtained sheet was evaluated.

[Comparative Example 2]
A blend was obtained in the same manner as in Example 1 except that vinylethoxysilane was replaced by 1.8 parts by weight as the ethylenically unsaturated silane compound (B2), and a sheet was further obtained. The obtained sheet was evaluated.

Claims (19)

An ethylene resin composition containing a modified polymer obtained by modifying an ethylene polymer (A) that simultaneously satisfies the following requirements a) to e) with an ethylenically unsaturated silane compound (B):
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 min d) Mw / Mn is 1.2 to 3.5
e) 0.1-50 ppm of metal residue
The ethylenically unsaturated silane compound (B) contains (B1) at least one selected from vinyltrimethoxysilane or 3-acryloxypropyltrimethoxysilane and (B2) vinyltriethoxysilane. Ethylene-based resin composition. The amount of the ethylenically unsaturated silane compound (B1) is 0.5 to 1.5 parts by weight with respect to 100 parts by weight of the ethylene polymer (A), and the ethylenically unsaturated silane compound (B2). The ethylene-based resin composition according to claim 1, wherein the blending amount is 0.1 to 1.5 parts by weight.   The modified polymer of the ethylene polymer (A) is obtained by extrusion melting a mixture of an ethylene polymer (A), an ethylenically unsaturated silane compound (B) and an organic peroxide. The ethylene-based resin composition described. 2. The ethylene resin composition according to claim 1, wherein the amount of the ethylenically unsaturated silane compound (B) is 0.6 to 3.0 parts by weight with respect to 100 parts by weight of the ethylene polymer (A). .   Modification obtained by modifying ethylene / α-olefin copolymer (C) with at least one selected from (B1) vinyltrimethoxysilane or 3-acryloxypropyltrimethoxysilane and (B2) vinyltriethoxysilane The ethylene-based resin composition according to claim 1, further comprising a copolymer. The ethylene-based resin composition according to claim 5, wherein the ethylene / α-olefin copolymer (C) satisfies the following requirement f).
f) Density is less than 850-900 kg / m ³   The modified polymer of ethylene / α-olefin copolymer (C) is obtained by extruding and melting a mixture of ethylene / α-olefin copolymer (C), ethylenically unsaturated silane compound (B) and organic peroxide. The ethylene-based resin composition according to claim 5, obtained by   The ethylene resin composition according to claim 4, wherein the ethylene polymer (A) is a powder. The ethylene-based resin composition according to claim 4, wherein the ethylene-based polymer (A) is a mixture of powder and pellets.   The mixture is a mixture of a powder of an ethylene polymer (A) preliminarily impregnated with an ethylenically unsaturated silane compound (B) and an organic peroxide, and a pellet of the ethylene polymer (A). The ethylene resin composition according to claim 9.   The ethylene resin composition according to claim 1, further comprising at least one additive selected from the group consisting of an ultraviolet absorber (D), a light stabilizer (E), and a heat-resistant stabilizer (F).   The modified weight of the ethylene / α-olefin copolymer (C) with respect to 100 parts by weight in total of the modified polymer of the ethylene polymer (A) and the modified polymer of the ethylene / α-olefin copolymer (C). The ethylene resin composition according to claim 5, wherein the content of the coalescence is 90 parts by weight or less.   The solar cell sealing material containing the ethylene-type resin composition of Claim 1.   The solar cell sealing material containing the ethylene-type resin composition of Claim 5.   The solar cell sealing material containing the sheet | seat which consists of an ethylene-type resin composition of Claim 1.   The said solar cell sealing material is a solar cell sealing material of Claim 15 integrated with the back surface protection member for solar cell modules.   The solar cell module obtained using the solar cell sealing material of Claim 15.   A thin film solar cell module obtained by using the solar cell encapsulant according to claim 15. A crystalline solar cell module obtained by using the solar cell encapsulant according to claim 15 as a solar cell encapsulant on the back surface side.