JP5764481B2 - Multilayer for solar cell - Google Patents

Description

  The present invention relates to a solar cell multilayer body that has excellent moisture resistance, transparency, and heat resistance, and can provide excellent sealing properties and handling properties when manufacturing a solar cell module.

In recent years, with increasing awareness of environmental issues such as global warming, expectations are increasing especially for photovoltaic power generation in terms of its cleanliness and non-polluting properties. The solar cell constitutes the central part of a photovoltaic power generation system that directly converts sunlight energy into electricity. In general, a plurality of solar cell elements (cells) are wired in series and in parallel as the structure, and various packaging is performed to protect the cells, thereby forming a unit. The unit incorporated in this package is called a solar cell module. Generally, the surface exposed to sunlight is covered with a transparent base material (front sheet) such as glass as an upper protective material, and a thermoplastic (for example, ethylene-vinyl acetate) The gap is filled with a resin layer (encapsulant) made of a copolymer, and the back surface is protected by a back surface sealing sheet (back sheet) with the lower protective material.
Since these solar cell modules are mainly used outdoors, various characteristics are required for the structure and material structure thereof. The above-mentioned encapsulant has flexibility and impact resistance for protecting the solar cell element, heat resistance when the solar cell module generates heat, and transparency for efficiently reaching the solar cell element ( Total light transmittance, etc.), durability, dimensional stability, flame retardancy, moisture resistance, etc. are mainly required.

Currently, an ethylene-vinyl acetate copolymer (hereinafter sometimes abbreviated as EVA) is widely used as a material for sealing a solar cell element in a solar cell module from the viewpoint of flexibility, transparency and the like. (For example, refer to Patent Document 1). In addition, for the main purpose of imparting heat resistance to EVA, crosslinking using an organic peroxide as a crosslinking agent is performed. Therefore, the process of producing the EVA sheet | seat which added the crosslinking agent (organic peroxide) and the crosslinking adjuvant in advance, and sealing a solar cell element using the obtained sheet | seat is employ | adopted.
However, when a solar cell module is manufactured using an EVA sheet, acetic acid gas is generated due to thermal decomposition of EVA due to various conditions such as thermocompression bonding, which adversely affects the work environment and manufacturing apparatus, and circuit corrosion of the solar cell. In addition, there is a problem such as peeling that occurs at the interface of each member such as a solar cell element, a front sheet, and a back sheet.
Further, EVA has insufficient water vapor barrier properties (for example, a water vapor permeability of about 25 to 35 g / (m ² · 24 hours) at a thickness of 0.3 mm, a temperature of 40 ° C., and a relative humidity of 90%), and a high humidity When used in an environment such as, there is a problem that moisture reaches the solar cell element, causing deterioration of the solar cell and a decrease in power generation efficiency.

  Therefore, in order to solve the above-described problem, a sealing material that is more moisture-proof than EVA has been studied. For example, it is known that a cyclic olefin polymer in which a cyclic olefin is introduced into a molecular chain is not only excellent in transparency but also excellent in moisture resistance. As a solar cell encapsulating material using such a cyclic olefin polymer, Patent Document 2 discloses a solar cell encapsulating material comprising a resin composition containing a norbornene-based ring-opening polymer hydride as a cyclic olefin resin. It is disclosed. Further, Patent Document 3 discloses a solar cell encapsulant sheet obtained by adding a C9 aromatic hydrocarbon resin to EVA, although it is not intended to improve moisture resistance.

JP 58-60579 A JP 2009-79101 A JP 2010-171419 A

  However, the sealing material using EVA typified by Patent Document 1 has a low elastic modulus at room temperature, lacks rigidity as a solar cell module support, or causes a problem in handling properties when manufacturing a solar cell module. Sometimes.

  Further, Patent Document 2 has no description or suggestion regarding sealing properties when sealing solar cell elements. For example, in order to improve the fluidity (fillability) of the sealing resin, the sealing step is performed at high temperature and high pressure. In the case of performing the above, problems such as deterioration of the solar cell element and wiring due to high temperature, or damage of the solar cell element due to overpressure may occur.

  In addition, for example, in a batch type solar cell module manufacturing facility, a vacuum laminator generally used in a sealing process uses a differential pressure of a vacuum degree using a vacuum pump, so that the pressure applied to the solar cell module is almost large. Atmospheric pressure (about 101.3 MPa). On the other hand, in order to increase the pressure at the time of sealing the solar cell element in order to use the sealing material described in Patent Document 2, it is necessary to remodel the pressure bonding method to a hydraulic type or the like, and the manufacturing cost is high. Become.

  Furthermore, in the technique described in Patent Document 3, although the C9 aromatic hydrocarbon resin is added to EVA, the moisture resistance is slightly improved as compared with the case where the C9 aromatic hydrocarbon resin is not added. In addition, it is difficult to obtain sufficient moisture resistance to suppress deterioration of the solar cell element due to moisture.

  Therefore, in view of the problems of the prior art, the object of the present invention is to provide moisture resistance sufficient for protection of solar cell elements, excellent transparency, heat resistance, and excellent sealing when manufacturing solar cell modules. It is providing the multilayer body for solar cells which has the property for providing a property and handling property in normal temperature, and a solar cell module produced using the same.

The present invention contains an ethylene-α-olefin random copolymer (A) that satisfies the following condition (a) and an ethylene-α-olefin block copolymer (B) that satisfies the following condition (b): A resin layer (II) containing an ethylene polymer (C) satisfying the following condition (c) and a crystal nucleating agent (D) as at least one of the outermost layers of the resin layer (I) ), And a solar cell module manufactured using the same.
(A): The crystal melting heat quantity measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 70 J / g.
(B): The crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100-145 ° C., and the crystal melting heat amount is 5-70 J / g.
(C): The crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 to 145 ° C., and the crystal melting heat amount is 120 to 190 J / g.

  Since the multilayer body for solar cell of the present invention is excellent in moisture resistance, it can suppress deterioration due to moisture absorption of the solar cell element, and can be used for a long time even under high humidity. Moreover, since it is excellent also in transparency, it has the same power generation efficiency as a solar cell module using a general solar cell sealing material. Furthermore, in addition to heat resistance, it is excellent in sealing property and handling property, so it can be widely used as a solar cell sealing material excellent in productivity in the solar cell module manufacturing process.

It is a schematic sectional drawing which shows an example of the solar cell module of this invention.

[Resin layer (I)]
The resin layer (I) comprises an ethylene-α-olefin random copolymer (A) satisfying the condition (a) and an ethylene-α-olefin block copolymer (B) satisfying the condition (b). ) And mainly has excellent sealing properties for protecting solar cell elements (cells), heat resistance, and excellent transparency for imparting sufficient power generation efficiency to solar cells. .

<Ethylene-α-olefin random copolymer (A)>
The ethylene-α-olefin random copolymer (A) used in the present invention is not particularly limited as long as the above condition (a) is satisfied. Usually, ethylene and an α-olefin having 3 to 20 carbon atoms are used. These random copolymers are preferably used. Examples of the α-olefin copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 3-methyl-butene. -1,4-methyl-pentene-1 and the like. In the present invention, propylene, 1-butene, 1-hexene, and 1-octene are preferably used as the α-olefin copolymerized with ethylene from the viewpoints of industrial availability, various characteristics, and economical efficiency. It is done. The α-olefin copolymerized with ethylene may be used alone or in combination of two or more.

  Further, the content of the α-olefin copolymerized with ethylene is not particularly limited as long as the above condition (a) is satisfied. However, the content of all units in the ethylene-α-olefin random copolymer (A) is not limited. It is 2 mol% or more normally with respect to a monomer unit, Preferably it is 40 mol% or less, More preferably, it is 3-30 mol%, More preferably, it is 5-25 mol%. Within this range, the crystallinity is reduced by the copolymerization component, so that the transparency is improved and problems such as blocking of the raw material pellets are less likely to occur. In addition, the kind and content of the α-olefin copolymerized with ethylene can be qualitatively and quantitatively analyzed by a well-known method, for example, a nuclear magnetic resonance (NMR) measuring apparatus or other instrumental analyzer.

  The ethylene-α-olefin random copolymer (A) may contain monomer units based on monomers other than the α-olefin, as long as the condition (a) is satisfied. Examples of the monomer include cyclic olefins, vinyl aromatic compounds (such as styrene), polyene compounds, and the like. The content of the monomer unit is 20 mol% or less and 15 mol% or less when the total monomer units in the ethylene-α-olefin random copolymer (A) is 100 mol%. It is preferable. Further, the steric structure, branching, branching degree distribution and molecular weight distribution of the ethylene-α-olefin random copolymer (A) are not particularly limited as long as the condition (a) is satisfied. A copolymer having a branch generally has good mechanical properties, and has an advantage that the melt tension (melt tension) at the time of molding a sheet is increased and the calendar moldability is improved. A copolymer having a narrow molecular weight distribution polymerized using a single site catalyst has advantages such as a low molecular weight component and a relatively low blocking of raw material pellets.

  The melt flow rate (MFR) of the ethylene-α-olefin random copolymer (A) used in the present invention is not particularly limited, but is usually MFR (JIS K7210, temperature: 190 ° C., load: 21. 18N) is about 0.5 to 100 g / 10 min, more preferably 2 to 50 g / 10 min, still more preferably 3 to 30 g / 10 min. Here, the MFR may be selected in consideration of molding processability when molding a sheet, adhesion when sealing a solar cell element (cell), a wraparound condition, and the like. For example, when the sheet is calendered, the MFR is preferably a relatively low value, specifically about 0.5 to 5 g / 10 minutes, because of the handling properties when the sheet is peeled off from the forming roll. When extruding using a die, the MFR is preferably 2 to 50 g / 10 min, more preferably 3 to 30 g / 10 min from the viewpoint of reducing the extrusion load and increasing the extrusion rate. Good. Furthermore, MFR is preferably 2 to 50 g / 10 min, more preferably 3 to 30 g / 10 min from the viewpoint of adhesion and ease of wrapping when sealing solar cell elements (cells). Use it.

  The production method of the ethylene-α-olefin random copolymer (A) used in the present invention is not particularly limited, and a known polymerization method using a known olefin polymerization catalyst can be employed. For example, slurry polymerization method, solution polymerization method, bulk polymerization method, gas phase polymerization method using multi-site catalyst represented by Ziegler-Natta type catalyst, single site catalyst represented by metallocene catalyst and post metallocene catalyst And a bulk polymerization method using a radical initiator. In the present invention, since the ethylene-α-olefin random copolymer (A) is a relatively soft resin, it has a low molecular weight from the viewpoint of easy granulation after polymerization and prevention of blocking of raw material pellets. A polymerization method using a single site catalyst capable of polymerizing a raw material with few components and a narrow molecular weight distribution is suitable.

  The ethylene-α-olefin random copolymer (A) used in the present invention satisfies the above condition (a), that is, the heat of crystal fusion measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 0. It is necessary to be 70 J / g, preferably 5 to 70 J / g, and more preferably 10 to 65 J / g. If it is in the range of 0-70 J / g, since the softness | flexibility, transparency (total light transmittance), etc. of the multilayer body for solar cells of this invention are ensured, it is preferable. In particular, if the heat of crystal fusion is 5 J / g or more, it is preferable because problems such as blocking of raw material pellets hardly occur. Here, as reference values for the heat of crystal fusion, general-purpose high-density polyethylene (HDPE) is about 170 to 220 J / g, and low-density polyethylene resin (LDPE) and linear low-density polyethylene (LLDPE) are 100 to 160 J. / G or so. The heat of crystal melting can be measured at a heating rate of 10 ° C./min according to JIS K7122 using a differential scanning calorimeter.

  Further, the crystal melting peak temperature of the ethylene-α-olefin random copolymer (A) used in the present invention is not particularly limited, but is usually less than 100 ° C. and often 30 to 90 ° C. . Here, as reference values for the crystal melting peak temperature, general-purpose high-density polyethylene (HDPE) is about 130 to 145 ° C., and low-density polyethylene resin (LDPE) and linear low-density polyethylene (LLDPE) are 100 to 125. It is about ℃. That is, with the ethylene-α-olefin random copolymer (A) alone used in the present invention, the crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 ° C. or higher, and It is difficult to achieve a heat of crystal melting of 5 to 70 J / g. The crystal melting peak temperature can be measured at a heating rate of 10 ° C./min according to JIS K7121 using a differential scanning calorimeter.

  Specific examples of the ethylene-α-olefin random copolymer (A) used in the present invention include trade names “Engage”, “Affinity” manufactured by Dow Chemical Co., Ltd., Mitsui Chemicals, Inc. Trade name “TAFMER A”, “TAFMER P”, product name “KARNEL” manufactured by Nippon Polyethylene Co., Ltd., and the like.

<Ethylene-α-olefin block copolymer (B)>
The ethylene-α-olefin block copolymer (B) used in the present invention is not particularly limited as long as the above condition (b) is satisfied. Usually, ethylene and an α-olefin having 3 to 20 carbon atoms are used. These block copolymers are preferably used. Examples of the α-olefin copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 3-methyl-butene. -1,4-methyl-pentene-1 and the like. In the present invention, propylene, 1-butene, 1-hexene, and 1-octene are preferably used as the α-olefin copolymerized with ethylene from the viewpoints of industrial availability, various characteristics, and economical efficiency. It is done. The α-olefin copolymerized with ethylene may be used alone or in combination of two or more.

  Further, the ethylene-α-olefin block copolymer (B) may contain monomer units based on monomers other than α-olefin as long as the condition (b) is satisfied. Examples of the monomer include cyclic olefins, vinyl aromatic compounds (such as styrene), polyene compounds, and the like. The content of the monomer unit is 20 mol% or less and 15 mol% or less when the total monomer units in the ethylene-α-olefin block copolymer (B) is 100 mol%. It is preferable.

  The block structure of the ethylene-α-olefin block copolymer (B) used in the present invention is not particularly limited as long as the condition (b) is satisfied, but the balance of flexibility, heat resistance, transparency, etc. Multi-block containing two or more, preferably three or more segments or blocks having different comonomer contents, crystallinity, density, crystal melting peak temperature (melting point Tm), or glass transition temperature (Tg) A structure is preferred. Specific examples include a completely symmetric block, an asymmetric block, and a tapered block structure (a structure in which the ratio of the block structure gradually increases in the main chain). Regarding the structure and production method of the copolymer having the multi-block structure, International Publication No. 2005/090425 (WO2005 / 090425), International Publication No. 2005/090426 (WO2005 / 090426), and International Publication No.2005. / 090427 pamphlet (WO2005 / 090427) or the like can be employed.

In the present invention, the ethylene-α-olefin block copolymer having the multi-block structure will be described in detail below.
The ethylene-α-olefin block copolymer having a multiblock structure can be suitably used in the present invention, and an ethylene-octene multiblock copolymer having 1-octene as a copolymerization component as an α-olefin is preferable. As the block copolymer, an almost non-crystalline soft segment copolymerized with a large amount of octene component (about 15 to 20 mol%) with respect to ethylene and a small amount of octene component with respect to ethylene (about 2 mol%). Less) a multiblock copolymer in which two or more highly crystalline hard segments each having a copolymerized crystal melting peak temperature of 100 to 145 ° C. are present. By controlling the chain length and ratio of these soft segments and hard segments, both flexibility and heat resistance can be achieved. As a specific example of the copolymer having the multi-block structure, trade name “Infuse” manufactured by Dow Chemical Co., Ltd. may be mentioned.

The melt flow rate (MFR) of the ethylene-α-olefin block copolymer (B) used in the present invention is not particularly limited, but is usually MFR (JIS K7210, temperature: 190 ° C., load: 21. 18N) is about 0.5 to 100 g / 10 min, more preferably 1 to 50 g / 10 min, still more preferably 1 to 30 g / 10 min, and particularly preferably 1 to 10 g / 10 min.
Here, the MFR may be selected in consideration of molding processability when molding a sheet, adhesion when sealing a solar cell element (cell), a wraparound condition, and the like. Specifically, when calendering the sheet, the MFR is preferably relatively low, specifically about 0.5 to 5 g / 10 minutes, from the handling properties when the sheet is peeled off from the forming roll, Moreover, when extrusion-molding using a T die, a MFR of 1 to 30 g / 10 min is preferably used from the viewpoint of reducing the extrusion load and increasing the extrusion amount. Furthermore, from the viewpoint of adhesion and ease of wraparound when sealing a solar cell element (cell), a MFR of 3 to 50 g / 10 min is preferably used.

  The ethylene-α-olefin block copolymer (B) used in the present invention satisfies the condition (b), that is, the crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100. It is necessary to be ˜145 ° C. and the heat of crystal melting is 5 to 70 J / g. The crystal melting peak temperature is preferably 105 ° C. or higher, more preferably 110 ° C. or higher, and the upper limit is usually 145 ° C. Further, the heat of crystal fusion is preferably 10 to 60 J / g, and more preferably 15 to 55 J / g. The method for measuring the crystal melting peak temperature and the crystal melting heat amount is as described above.

  In general, a solar cell module is heated to about 85 to 90 ° C. by heat generated during power generation or radiant heat of sunlight, but if the crystal melting peak temperature is 100 ° C. or higher, the heat resistance of the multilayer body for solar cell of the present invention is increased. On the other hand, if the upper limit is 145 ° C., it is preferable because it can be sealed without excessively high temperature in the sealing step of the solar cell element. Moreover, if the amount of heat of crystal melting is in the range of 5 to 70 J / g, the flexibility and transparency (total light transmittance) of the multilayer body for solar cell of the present invention are secured, and blocking of raw material pellets and the like It is preferable because defects are unlikely to occur.

<Resin layer (I)>
The resin layer (I) in the multilayer body for solar cell of the present invention is a resin layer containing the ethylene-α-olefin random copolymer (A) and the ethylene-α-olefin block copolymer (B). . Here, the type of α-olefin used in each of these copolymers (A) and (B) may be the same or different, but in the present invention, It is preferable that they are the same because the compatibility when mixed and the transparency of the multilayer body for solar cell are improved, that is, the photoelectric conversion efficiency of the solar cell is improved.

  Next, the contents of the ethylene-α-olefin random copolymer (A) and the ethylene-α-olefin block copolymer (B) in the resin layer (I) include flexibility, heat resistance, transparency, and the like. From the viewpoint of having an excellent balance, it is preferably 50 to 99% by mass and 1 to 50% by mass, more preferably 60 to 98% by mass and 2 to 40% by mass, and still more preferably 70 to 70% by mass. It is -97 mass% and 3-30 mass%. Further, the mixing (containing) mass ratio of the ethylene-α-olefin random copolymer (A) and the ethylene-α-olefin block copolymer (B) is not particularly limited, but preferably (A). / (B) = 99-50 / 1-50, more preferably 98-60 / 2-40, more preferably 97-70 / 3-30, more preferably 97-80 / 3-20, Preferably, it is 97-90 / 3-10. However, the total of (A) and (B) is 100 parts by mass. Here, it is preferable that the mixing (containing) mass ratio is within the above range because a multilayer body for solar cells excellent in balance of flexibility, heat resistance, transparency and the like can be easily obtained.

  Although the thickness in particular of resin layer (I) is not restrict | limited, From a viewpoint of the sealing performance of a solar cell element (cell), it is preferable that it is 0.02-0.7 mm, and is 0.05-0.6 mm. It is more preferable.

[Resin layer (II)]
The resin layer (II) is provided on at least one side of the resin layer (I), and contains an ethylene polymer (C) that satisfies the condition (c), and a crystal nucleating agent (D). Mainly to provide excellent moisture resistance to suppress deterioration due to moisture such as solar cell elements (cells) and wiring, handleability of sealing materials when manufacturing solar cell modules, and sufficient power generation efficiency to solar cells It has a role of imparting excellent transparency.

<Ethylene polymer (C)>
The ethylene polymer (C) used for the solar cell multilayer body of the present invention is not particularly limited as long as the above condition (c) is satisfied, but may be an ethylene homopolymer, or Further, it may be a copolymer of ethylene and α-olefin. Moreover, these mixtures can be used. Examples of the α-olefin copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 3-methyl-butene. -1,4-methyl-pentene-1 and the like. In the present invention, propylene, 1-butene, 1-hexene, and 1-octene are preferably used as the α-olefin copolymerized with ethylene from the viewpoints of industrial availability, various characteristics, and economical efficiency. It is done. The α-olefin copolymerized with ethylene may be used alone or in combination of two or more. Among these, it is preferable to use an ethylene homopolymer or a copolymer of ethylene and butene-1, and / or hexene-1, and / or octene-1.

  When using a copolymer of ethylene and α-olefin, the total of the proportions of butene-1, hexene-1 and octene-1 in the copolymer is 0.1 to 3.0% by mass. Among these, 0.3% by mass or more or 2.8% by mass or less is preferable, and among them, 0.5% by mass or more or 2.6% by mass or less is more preferable. When the α-olefin is within such a range, it is possible to provide a solar cell multilayer body excellent in moisture resistance, rigidity, and transparency.

  The catalyst used for the polymerization of the ethylene polymer (C) is not particularly limited. For example, a Ziegler-Natta catalyst composed of titanium chloride and an organoaluminum compound, a Philips catalyst composed of a chromium compound such as chromium oxide, and a metallocene compound And the like. Among them, it is particularly preferable to use a single site catalyst.

  Since ethylene homopolymers and ethylene-α-olefin random copolymers polymerized using a single site catalyst have a small molecular weight distribution index (Mw / Mn) and a relatively uniform molecular length, When a nucleating agent is added, it is possible to form fine crystals, so that transparency and moisture resistance can be particularly improved. In view of the above, the molecular weight distribution index (Mw / Mn) of the ethylene polymer (C) is 2.5 to 4.5, particularly 2.6 or more and 4.3 or less, especially 3.0 or more or 4 0.0 or less is preferable. The molecular weight distribution index (Mw / Mn) is obtained from the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured using a high temperature GPC system.

  Examples of single site catalysts that can be used include metallocene catalysts in which a metallocene compound and methylaluminoxane are combined. Features of ethylene homopolymers and / or ethylene-α-olefin random copolymers polymerized using a single site catalyst include narrow molecular weight distribution and low heat of crystal fusion even at the same density Can be mentioned.

The density of the ethylene polymer (C) is preferably a 0.910~0.948g / cm ^3, more that 0.915 g / cm ³ or more, or 0.947 g / cm ³ or less Preferably, it is 0.920 g / cm ³ or more or 0.942 g / cm ³ or less. If the density of the said ethylene-type polymer (C) is in the range which requires, the rigidity, moisture-proof property, and transparency which were excellent in the multilayer body for solar cells of this invention can be provided.

The ethylene polymer (C) used in the present invention satisfies the condition (c), that is, the crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 to 145 ° C. In addition, the heat of crystal melting needs to be 120 to 190 J / g. More preferably, the crystal melting peak temperature is 105 ° C. or higher, more preferably 110 ° C. or higher, and the upper limit is 145 ° C. More preferably, the heat of crystal fusion is 130 to 185 J / g, still more preferably 140 to 183 J / g. The method for measuring the crystal melting peak temperature and the crystal melting heat amount is as described above.
As long as the crystal melting peak temperature and the heat of crystal melting of the ethylene polymer (C) are within such ranges, the solar cell multilayer body of the present invention can be provided with excellent rigidity, moisture resistance, and transparency.

<Crystal nucleating agent (D)>
The crystal nucleating agent (D) contained in the resin layer (II) of the multilayer body for solar cell of the present invention is mainly improved in transparency by reducing the spherulite size of the ethylene polymer (C), There is an increase in heat of fusion and an effect of improving rigidity, and the type is not particularly limited. For example, dibenzylidene sorbitol (DBS) compounds, 1,3-O-bis (3,4 dimethyl benzylidene) sorbitol, dialkyl benzylidene sorbitol, diacetals of sorbitol having at least one chlorine or bromine substituent, di (methyl or ethyl substituted benzylidene) ) Sorbitol, bis (3,4-dialkylbenzylidene) sorbitol with substituents forming carbocycles, aliphatic, alicyclic and aromatic carboxylic acids, dicarboxylic acids or polybasic polycarboxylic acids, corresponding anhydrides Metal salts of organic acids such as organic and metal salts, bicyclic dicarboxylic acids and salts such as cyclic bis-phenol phosphate, disodium bicyclo [2.2.1] heptene dicarboxylic acid, bicyclo [2.2 .1] Heptane-dicarboxylate Bicyclic dicarboxylate saturated metal or organic salt compounds such as 1,3: 2,4-O-dibenzylidene-D-sorbitol, 1,3: 2,4-bis-O- (m- Methylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (m-ethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (m-isopropylbenzylidene)- D-sorbitol, 1,3: 2,4-bis-O- (mn-propylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (mn-butylbenzylidene)- D-sorbitol, 1,3: 2,4-bis-O- (p-methylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (p-ethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- p-isopropylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (pn-propylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (p- n-butylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (2,3-dimethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (2, 4-dimethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (2,5-dimethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (3 4-dimethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (3,5-dimethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (2, 3-Diethylbenzylidene) -D-sorbite 1,3: 2,4-bis-O- (2,4-diethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (2,5-diethylbenzylidene) -D -Sorbitol, 1,3: 2,4-bis-O- (3,4-diethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (3,5-diethylbenzylidene) -D -Sorbitol, 1,3: 2,4-bis-O- (2,4,5-trimethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (3,4,5-trimethyl) Benzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (2,4,5-triethylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (3,4 , 5-triethylbenzylidene) -D-sorbitol, 1,3: 2, -Bis-O- (p-methyloxycarbonylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (p-ethyloxycarbonylbenzylidene) -D-sorbitol, 1,3: 2,4 -Bis-O- (p-isopropyloxycarbonylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (on-propyloxycarbonylbenzylidene) -D-sorbitol, 1,3: 2 , 4-bis-O- (on-butylbenzylidene) -D-sorbitol, 1,3: 2,4-bis-O- (o-chlorobenzylidene) -D-sorbitol, 1,3: 2,4 -Bis-O- (p-chlorobenzylidene) -D-sorbitol, 1,3: 2,4-bis-O-[(5,6,7,8, -tetrahydro-1-naphthalene) -1-methylene] − -Sorbitol, 1,3: 2,4-bis-O-[(5,6,7,8, -tetrahydro-2-naphthalene) -1-methylene] -D-sorbitol, 1,3-O-benzylidene- 2,4-Op-methylbenzylidene-D-sorbitol, 1,3-Op-methylbenzylidene-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4- Op-ethylbenzylidene-D-sorbitol, 1,3-Op-ethylbenzylidene-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-Op- Chlorbenzylidene-D-sorbitol, 1,3-O-p-chlorobenzylidene-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-O- (2,4-dimethyl Benzylidene) -D-sorbitol, 1,3-O- (2,4-dimethylbenzylidene) -2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2,4-O- (3 , 4-Dimethylbenzylidene) -D-sorbitol, 1,3-O- (3,4-dimethylbenzylidene) -2,4-O-benzylidene-D-sorbitol, 1,3-Op-methyl-benzylidene- 2,4-O-p-ethylbenzylidenesorbitol, 1,3-p-ethyl-benzylidene-2,4-p-methylbenzylidene-D-sorbitol, 1,3-Op-methyl-benzylidene-2,4 Dia, such as -Op-chlorobenzylidene-D-sorbitol, 1,3-Op-chloro-benzylidene-2,4-Op-methylbenzylidene-D-sorbitol Tar compounds, sodium 2,2′-methylene-bis- (4,6-di-tert-butylphenyl) phosphate, aluminum bis [2,2′-methylene-bis- (4-6-di-tert-butylphenyl) ) Phosphate], sodium 2,2-methylenebis (4,6-di-tert-butylphenyl) phosphate, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid Acids, fatty acids such as pentadecanoic acid, palmitic acid, margaric acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, montanic acid, fatty acid amides such as oleic acid amide, erucic acid amide, stearic acid amide, hebenic acid amide, stearin Magnesium oxide, zinc stearate, calcium stearate And fatty acid metal salts such as um, inorganic particles such as silica, talc, kaolin and calcium carbide, higher fatty acid esters such as glycerol and glycerol monoester, and the like.

  Among these, fatty acid amides such as oleic acid amide, erucic acid amide, stearic acid amide, and hebenic acid amide, and fatty acid metal salts such as magnesium stearate, zinc stearate, and calcium stearate are particularly preferable from the viewpoint of transparency and the like.

  As specific examples of the crystal nucleating agent (D), Shin Nippon Rika Co., Ltd., trade name “Gelall D” series, Asahi Denka Kogyo Co., Ltd., trade name “Adeka Stub” series, Miliken Chemical Co., Ltd., trade name “ "Millad" series, "Hyperform" series, BASF Corporation's trade name "IRGACLEAR" series, and the like. As a master batch of crystal nucleating agent, Riken Vitamin Co., Ltd. trade name "Rike Master CN" series, Miliken A trade name “HL3-4” of Chemical Co., Ltd. and the like can be mentioned. Among them, those having a particularly high effect of improving transparency include trade names “MYPHERFORM HPN-20E” and “HL3-4” of Milliken Chemical Co., Ltd., and “Rike Master CN-001” of Riken Vitamin Co., Ltd. “Rike Master CN-002” can be mentioned.

<Olefin compatible resin (E)>
The resin layer (II) preferably further contains an olefin-compatible resin (E) from the viewpoint of further improving moisture resistance.
As the olefin compatible resin (E), the softening temperature Ts (E) which is compatible with the olefin resin, particularly the ethylene polymer (C), and is measured based on JIS K2207 of the olefin compatible resin (E). ) Is preferably a crystallization peak temperature Tc (C) + 5 ° C. or less measured at a cooling rate of 10 ° C./min in differential scanning calorimetry according to JIS K7121 of the ethylene polymer (C), for example, petroleum Examples thereof include one resin or two or more resins selected from the group consisting of resins, terpene resins, coumarone-indene resins, rosin resins, and hydrogenated derivatives thereof.

Examples of the petroleum resin include alicyclic petroleum resin from cyclopentadiene or its dimer, aromatic petroleum resin from C9 component, and the like.
Examples of the terpene resin include terpene-phenol resin from β-pinene.
Examples of the coumarone-indene resin include a coumarone-indene copolymer and a coumarone-indene-styrene copolymer.
Examples of the rosin resin include rosin resins such as gum rosin and wood rosin, and esterified rosin resins modified with glycerin, pentaerythritol, and the like.

Such an olefin-compatible resin (E) is a hydrogenated derivative, particularly hydrogen, from the viewpoint of further improving the compatibility, color tone, thermal stability, moist heat resistance and the like when mixed with the ethylene polymer (C). Addition rate (hereinafter referred to as “hydrogenation rate”, determined from the proportion of unsaturated double bonds of conjugated diene based on phenyl group from ¹ H-NMR spectrum) is 95% or more, and is a hydroxyl group or carboxyl group It is preferable to use a petroleum resin or a terpene resin substantially free of a polar group such as halogen or an unsaturated bond such as a double bond.

The olefin compatible resin (E) can be obtained in various softening temperatures by selecting the molecular weight.
In the solar cell multilayer body of the present invention, the softening temperature Ts (E) measured based on JIS K2207 of the olefin compatible resin (E) is the differential scanning calorific value according to JIS K7121 of the ethylene polymer (C). The crystallization peak temperature Tc (C) measured at a cooling rate of 10 ° C./min in the measurement is preferably 5 ° C. or less, more preferably the Tc (C) + 3 ° C. or less, and the Tc (C) + 2 ° C. It is below, More preferably, it is below this Tc (C), It is below this Tc (C) -5 degreeC. The lower limit of Ts (E) is 80 ° C. Since the upper limit of the softening temperature Ts (E) satisfies the above condition, the olefin-compatible resin (E) has a high degree of molecular freedom in the crystallization process of the ethylene polymer (C). Crystallization of the union (C) is not inhibited, fine crystals are formed, and a multilayer body for solar cells excellent in moisture resistance is obtained. Moreover, if the softening temperature Ts (E) of the olefin-compatible resin (E) is 80 ° C. or higher, the multilayer body for solar cell at the time of molding blocking, secondary processing, transportation, or use Less likely to bleed out to the surface.

  Specific examples of the olefin compatible resin (E) include, for example, Mitsui Chemical Co., Ltd., trade names “Hilets” series, “Petrogin” series, Arakawa Chemical Industries, Ltd., trade names “Arcon” series, Yashara Chemical ( For example, the “Clearon” series of trade names, the “Imabe” series of Idemitsu Petrochemical Co., Ltd., and the “Escollet” series of Tonex Co., Ltd. are listed.

<Cyclic olefin resin (F)>
The resin layer (II) preferably contains a cyclic olefin-based resin (F) from the viewpoint of further improving transparency.
As the cyclic olefin-based resin (F) used in the present invention, (i) a polymer obtained by hydrogenating a ring-opened (co) polymer of a cyclic olefin as necessary, (ii) an addition (co) polymer of a cyclic olefin, (Iii) Random copolymers of cyclic olefins and α-olefins such as ethylene and propylene, (iv) Graft-modified products obtained by modifying the above (i) to (iii) with unsaturated carboxylic acids or their derivatives, etc. . Specific examples include the “ZEONOR” series of ZEON Corporation, the “Apel” series of Mitsui Chemicals, and the “TOPAS” series of Polyplastics. The cyclic olefin polymers are described in, for example, JP-A-60-168708, JP-A-61-115916, JP-A-61-271308, JP-A-61-252407. It can also be produced according to known methods.

Further, in the present invention, the cyclic olefin ring-opening (co) polymer or the hydrogenated product of the cyclic olefin ring-opening (co) polymer is, for example, maleic anhydride, maleic acid, itaconic anhydride, itaconic acid, (meth) acrylic. A graft copolymer modified with a modifier of unsaturated carboxylic acid such as acid or its anhydride can also be used.
Moreover, the glass transition temperature (Tg) of the said cyclic olefin resin (F) becomes like this. Preferably it is 50-105 degreeC, More preferably, it is 55-90 degreeC. If the glass transition temperature of the cyclic olefin resin (F) is within such a range, the transparency of the multilayer body for solar cell of the present invention can be improved without deteriorating heat resistance and workability.

<Resin layer (II)>
The resin layer (II) in the multilayer body for solar cell of the present invention is a resin layer containing the ethylene polymer (C) and the crystal nucleating agent (D).

The content of the ethylene polymer (C) in the resin layer (II) is usually 30% by mass or more, preferably 30 to 90% by mass, and more preferably 40 to 80% by mass. . By blending the tyrene polymer (C) within such a range, excellent rigidity, moisture resistance and transparency can be imparted.
The content of the crystal nucleating agent (D) in the resin layer (II) can be appropriately determined within a range in which transparency and moisture resistance are good, but is 0.01 to 3% by mass. Among these, 0.03% by mass or more or 2% by mass or less is more preferable, and among them, 0.05% by mass or more or 1% by mass or less is particularly preferable. By blending the crystal nucleating agent (D) within such a range, the rigidity, moisture resistance, and transparency of the multilayer body for solar cell of the present invention can be reduced without causing a decrease in transparency due to excessive addition of the crystal nucleating agent. Can be improved.

  The content of the olefin-compatible resin (E) in the resin layer (II) is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, and 5 to 20% by mass. It is particularly preferred. By containing the olefin-compatible resin (E) within this range, the solar cell of the present invention does not cause bleeding of the olefin-compatible resin (E) to the surface of the solar cell multilayer body, deterioration of mechanical properties, and the like. The moisture resistance of the multilayer body for use can be further improved.

  The content of the cyclic olefin-based resin (F) in the resin layer (II) is preferably 10 to 50% by mass from the viewpoint of further improving transparency without impairing moisture resistance. More preferably, it is 45 mass%, and it is especially preferable that it is 25-30 mass%.

  In the present invention, the thickness of the resin layer (II) is not particularly limited, but is preferably 0.01 to 0.3 mm, and preferably 0.03 to 0.2 mm from the viewpoint of moisture resistance and transparency. It is more preferable.

<Other ingredients>
[Other resins]
In addition, the resin layer (I) and the resin layer (II) constituting the multilayer body for solar cell of the present invention have various physical properties (flexibility, heat resistance, transparency, within the scope not departing from the gist of the present invention). In the case of the resin layer (I), the ethylene-α-olefin random copolymer (A) and the ethylene-α-olefin block copolymer are used for the purpose of further improving the adhesiveness and the like, molding processability, and economic efficiency. Other than the polymer (B), if the resin layer (II), other resins other than the ethylene polymer (C), the olefin compatible resin (E), and the cyclic olefin resin (F) are mixed. be able to. Examples of the other resins include other polyolefin resins and various elastomers (olefin-based, styrene-based, etc.), carboxyl groups, amino groups, imide groups, hydroxyl groups, epoxy groups, oxazoline groups, thiol groups, silanol groups, and the like. Examples thereof include resins modified with polar groups.

[Additive]
Moreover, various additives can be added to the resin layer (I) and / or the resin layer (II) constituting the multilayer body for solar cell of the present invention, if necessary. Examples of the additive include a silane coupling agent, an antioxidant, an ultraviolet absorber, a weathering stabilizer, a light diffusing agent, a nucleating agent, a pigment (for example, a white pigment), a flame retardant, and a discoloration preventing agent. . In the present invention, in the resin layer (I), it is preferable that at least one additive selected from a silane coupling agent, an antioxidant, an ultraviolet absorber, and a weathering stabilizer is added for the reasons described later. . In the resin layer (II), it is preferable that at least one additive selected from an antioxidant, an ultraviolet absorber, and a weathering stabilizer is added, for the reason described later.

(Silane coupling agent)
Silane coupling agents are useful for improving adhesion to protective materials for sealing materials (glass, resin front sheets, back sheets, etc.) and solar cell elements, such as vinyl groups, Examples thereof include compounds having a hydrolyzable group such as an alkoxy group in addition to an unsaturated group such as an acryloxy group and a methacryloxy group, an amino group, and an epoxy group. Specific examples of the silane coupling agent include N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, and γ-aminopropyltriethoxy. Examples include silane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and the like. In the present invention, γ-glycidoxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane are preferably used because of good adhesiveness and little discoloration such as yellowing. The addition amount of this silane coupling agent is about 0.1-5 mass parts normally with respect to 100 mass parts of resin compositions which comprise each layer, and it is preferable to add 0.2-3 mass parts. In addition, similar to the silane coupling agent, a coupling agent such as an organic titanate compound can be effectively used.

(Antioxidant)
As the antioxidant, various commercially available products can be applied, and various types such as monophenol type, bisphenol type, polymer type phenol type, sulfur type and phosphite type can be exemplified. Examples of monophenols include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, and the like. Examples of bisphenols include 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4 '-Thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidene-bis- (3-methyl-6-tert-butylphenol), 3,9-bis [{1,1-dimethyl- 2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl} 2,4,9,10-tetraoxaspiro] 5,5-undecane.

Examples of the high molecular phenolic group include 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3 , 5-di-tert-butyl-4-bidoxybenzyl) benzene, tetrakis- {methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate} methane, bis { (3,3'-bis-4'-hydroxy-3'-tert-butylphenyl) butyric acid} glycol ester, 1,3,5-tris (3 ', 5'-di-tert-butyl-4 '-Hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione, triphenol (vitamin E) and the like.
Examples of sulfur-based compounds include dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiopropionate.

  Examples of the phosphite system include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, Crick neopentanetetrayl bis (octadecyl phosphite), tris (mono and / or di) phenyl phosphite, diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10 -Dihydro-9-oxa-10-fo Phaphenanthrene, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-tert-methylphenyl) phosphite, 2 , 2-methylenebis (4,6-tert-butylphenyl) octyl phosphite.

  In the present invention, phenol-based and phosphite-based antioxidants are preferably used in view of the effect of the antioxidant, thermal stability, economy, and the like, and it is more preferable to use both in combination. The addition amount of the antioxidant is usually about 0.1 to 1 part by mass and preferably 0.2 to 0.5 part by mass with respect to 100 parts by mass of the resin composition constituting each layer.

(UV absorber)
Examples of the ultraviolet absorber include various types such as benzophenone-based, benzotriazole-based, triazine-based, salicylic acid ester-based, and various commercially available products can be applied. Examples of the benzophenone-based UV absorber include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-n. -Dodecyloxybenzophenone, 2-hydroxy-4-n-octadecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-5-chlorobenzophenone, 2, , 4-dihydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, etc. But it can.

The benzotriazole ultraviolet absorber is a hydroxyphenyl-substituted benzotriazole compound, for example, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-t-butylphenyl) Benzotriazole, 2- (2-hydroxy-3,5-dimethylphenyl) benzotriazole, 2- (2-methyl-4-hydroxyphenyl) benzotriazole, 2- (2-hydroxy-3-methyl-5-t- Butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-amylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, etc. be able to. Examples of triazine ultraviolet absorbers include 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 2- ( And 4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) phenol. Examples of salicylic acid esters include phenyl salicylate and p-octylphenyl salicylate.
The addition amount of the ultraviolet absorber is usually about 0.01 to 2.0 parts by mass with respect to 100 parts by mass of the resin composition constituting each layer, and 0.05 to 0.5 parts by mass may be added. preferable.

(Light stabilizer)
A hindered amine light stabilizer is suitably used as a weather stabilizer that imparts weather resistance in addition to the above ultraviolet absorber. A hindered amine light stabilizer does not absorb ultraviolet rays like an ultraviolet absorber, but exhibits a remarkable synergistic effect when used together with an ultraviolet absorber. In addition to hindered amines, there are those that function as light stabilizers, but they are often colored and are not preferred for the solar cell encapsulant of the present invention.

  Examples of hindered amine light stabilizers include dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1 , 3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {{2, 2,6,6-tetramethyl-4-piperidyl} imino}], N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2, 6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3 , 5-Di-tert-4- Mud alkoxybenzylacetic) -2-n-butyl malonic acid bis (1,2,2,6,6-pentamethyl-4-piperidyl) and the like. The added amount of the hindered amine light stabilizer is usually about 0.01 to 0.5 parts by mass and added to 0.05 to 0.3 parts by mass with respect to 100 parts by mass of the resin composition constituting each layer. It is preferable to do.

[Multilayer for solar cells]
The multilayer body for solar cell of the present invention comprises the resin layer (II) on at least one side of the resin layer (I).
The multilayer body for solar cell of the present invention is excellent in moisture resistance, and has a water vapor transmission rate of 3. measured at a temperature of 40 ° C. and a relative humidity of 90% based on the JIS K7129B method when molded to a thickness of 0.3 mm. It is preferably 0 g / (m ² · 24 hours) or less, more preferably 2.0 g / (m ² · 24 hours) or less, and 1.0 g / (m ² · 24 hours) or less. Is more preferable. Such excellent moisture resistance in the present invention is mainly due to the combination of the ethylene polymer (C) and the crystal nucleating agent (D), as well as the olefin compatible resin (E) and the cyclic olefin resin (F). It can be achieved by addition or the like.

  The multi-layer body for solar cell of the present invention can be appropriately adjusted in its flexibility in consideration of the shape, thickness, installation location, etc. of the applied solar cell. Handling property when battery sealing material is collected, prevention of blocking between sheet surfaces, or weight reduction in solar cell module (usually about 3 mm, thin film glass (about 1.1 mm) is applicable, or glassless Is applicable), the storage elastic modulus (E ′) at a vibration frequency of 10 Hz and a temperature of 20 ° C. in the dynamic viscoelasticity measurement is preferably 100 to 1000 MPa, more preferably 150 to 900 MPa. Preferably, it is 200 MPa-800 MPa. The storage elastic modulus (E ′) can be obtained by measuring a predetermined temperature range at a vibration frequency of 10 Hz using a viscoelasticity measuring device and obtaining a value at a temperature of 20 ° C.

  The total light transmittance at a thickness of 0.3 mm based on JIS K7105 of the multilayer body for solar cell of the present invention does not block the type of solar cell to be applied, for example, amorphous thin film silicon type or sunlight reaching the solar electronic device. When applied to a part, it may not be very important, but considering the photoelectric conversion efficiency of the solar cell and workability when overlapping various members, it is preferably 85% or more, and 88% or more More preferably, it is more preferably 90% or more.

The heat resistance of the multilayer body for solar cell of the present invention is determined by various characteristics of the ethylene-α-olefin random copolymer (A) (crystal melting peak temperature, crystal melting heat amount, MFR, molecular weight, etc.) and ethylene-α-olefin block. Although it is influenced by various properties (crystal melting peak temperature, crystal melting heat amount, MFR, molecular weight, etc.) of the copolymer (B), the crystal melting peak temperature of the ethylene-α-olefin block copolymer (B) is particularly high. It has a strong influence. In general, the solar cell module is heated to about 85 to 90 ° C. by heat generated during power generation or radiant heat of sunlight, etc. If the crystal melting peak temperature is 100 ° C. or more, the heat resistance of the solar cell encapsulant of the present invention is increased. It is preferable because the property can be secured.
The thickness of the solar cell multilayer body of the present invention is not particularly limited, but is usually about 0.03 to 1 mm, and is preferably 0 from the viewpoints of transparency, moisture resistance, handling properties, and the like. Used in sheet form of 1 to 0.7 mm.

[Method for producing solar cell multilayer body]
Next, the manufacturing method of the multilayer body for solar cells of this invention is demonstrated.
As a method for forming a sheet-like multilayer for a solar cell, a known method, for example, an extrusion casting method using a T-die having a melt mixing facility such as a single screw extruder, a multi-screw extruder, a Banbury mixer, a kneader, etc. A calendering method, an inflation method, and the like can be adopted and are not particularly limited. In the present invention, however, an extrusion casting method using a T die is preferably used from the viewpoint of handling properties and productivity. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film forming properties of the resin composition constituting each resin layer, but is generally 130 to 300 ° C, preferably 150 to 250 ° C. It is. As a multilayering method, a known method such as coextrusion, extrusion lamination, heat lamination, dry lamination, or the like can be used.

  In the solar cell multilayer body of the present invention produced by the production method, the ratio of the resin layer (II) in the thickness direction is preferably 20% or more and 70% or less, and 30% or more and 60% or more. More preferably, it is 35% or more and 55% or less. If the ratio of the resin layer (II) is within such a range, excellent moisture resistance can be obtained, and sufficient transparency can be obtained. Moreover, as a structure of the multilayer body for solar cells of this invention, the resin layer (I) should just be provided as at least 1 layer of the outermost layer of a multilayer body, for example, resin layer (I) / resin layer (II ) Two-type two-layer configuration, and two-type three-layer configuration of resin layer (I) / resin layer (II) / resin layer (I). By adopting such a multi-layer structure, the protection of the solar cell element by the resin layer (I), the moisture resistance by the resin layer (II), and the handling property as a whole sealing material (elastic modulus at room temperature, etc.) It is preferable because both can be realized relatively easily. Further, since the multilayer body of the present invention is excellent in rigidity at normal temperature, a thin glass (eg, 1.1 mm) can be applied, or a structure such as glassless can be applied, and weight reduction can be expected.

  In addition, the multilayer body for solar cell of the present invention has a two-layer / two-layer structure of the above-described resin layer (I) / resin layer (II), or resin layer (I) / resin layer (II) / resin layer (I ) Is preferable, but it is also possible to adopt other laminated configurations for the purpose of improving the characteristics as a solar cell module and adjusting the appearance (such as improving warp). For example, resin layer (I) (with additive) / resin layer (I) (without additive) / resin layer (II), resin layer (I) (with additive A) / resin layer (I) ( (Including additive B) (additives A and B have different additive formulations) / resin layer (II), resin layer (I) ′ / resin layer (I) ″ (resin layer (I) ′ and (I ) '' Is different in storage modulus (E ′) and mixing ratio of additives) / resin layer (II), resin layer (I) / resin layer (II) ′ / resin layer (II) ″ (resin layer) (II) ′ and (II) ″ are different in storage elastic modulus (E ′) and mixing ratio of additives (three types and three layers), resin layer (I) / adhesive layer / resin layer (II) / adhesion Layer / resin layer (II), resin layer (I) / recycled layer / resin layer (II) / recycled layer / resin layer (I), and resin layer (I) / recycled layer / resin layer (II) / recycled Layer / resin layer (II), 3 types and 5 layers Such as the formation and the like.

  Various additives such as silane coupling agents, antioxidants, UV absorbers, and weathering stabilizers may be dry blended with the resin in advance and then supplied to the hopper. The master batch may be supplied after being prepared, or a master batch in which only the additive is previously concentrated in the resin may be prepared and supplied. Moreover, on the surface and / or the back surface of the solar cell encapsulant of the present invention obtained in the form of a sheet, if necessary, the sheet is prevented from blocking between sheets and the solar cell element is encapsulated. Embossing and various irregularities (cone, pyramid shape, hemispherical shape, etc.) may be performed for the purpose of improving the handleability and ease of bleeding.

  Furthermore, when producing the multilayer body for solar cells of the present invention, another base film (for example, stretched polyester film (OPET), stretched polypropylene film (OPP) or ETFE (tetrafluoroethylene / ethylene copolymer)). , PVF (polyvinyl fluoride), PVDF (polyvinylidene fluoride), acrylic weather-resistant films, etc.) and extrusion lamination, co-extrusion, sand lamination, etc. may be used for lamination. By laminating the solar cell multilayer body of the present invention and various substrate films, it is possible to adjust the required properties and economy relatively easily according to the improvement in handling properties and the lamination ratio.

[Solar cell module]
The multilayer body for solar cell of the present invention is used as a member for solar cell, and its part is not particularly limited, but mainly as a solar cell sealing material that adheres to and protects the solar cell element. It is also used as a multilayer body for sealing solar cells at a site, or a site that is not in close contact with a solar cell element for the purpose of adjusting flexibility, rigidity, curl, thickness and dielectric breakdown voltage of the entire solar cell module. Here, as a specific example of the portion that is not in close contact with the solar cell element, for example, the constituent layer of the upper protective material of the solar cell module such as the upper protective material / sealing material / solar cell element / sealing material / lower protective material As the outermost surface layer / multilayer body for solar cell of the present invention / barrier layer, outermost surface layer / barrier layer / multilayer body for solar cell of the present invention, outermost surface layer / multilayer body for solar cell of the present invention, outermost surface Layer / multilayer body for solar cell of the present invention / barrier layer / multilayer body for solar cell of the present invention, and the like. Back layer, other polyolefin layer (such as CPP) / multilayer body for solar cell of the present invention / barrier layer / outermost layer, other polyolefin layer (such as CPP) / barrier layer / multilayer body for solar cell of the present invention / Back layer and other polyolefin layers (CPP, etc.) A multilayer body / top back surface layer of the solar cell and the like. In addition, when the solar cell multilayer body of the present invention is used in a region that does not adhere to the solar cell element, the solar cell material that adheres to and protects the solar cell element includes the solar cell multilayer body of the present invention, or Commercially available EVA or ionomer solar cell materials can be used. Here, the solar cell module produced using the solar cell multilayer body of the present invention as a solar cell material that adheres to and protects the solar cell element will be described.

[Solar cell module]
Next, using the solar cell multilayer body of the present invention, a solar cell module can be produced by fixing the solar cell element with a front sheet and a back sheet which are upper and lower protective materials. Examples of such a solar cell module include various types, and preferably the solar cell multilayer body of the present invention is used as a sealing material, that is, a solar cell sealing multilayer body. Solar cell modules manufactured using a solar cell multilayer body, an upper protective material, a solar cell element, and a lower protective material. Specifically, an upper protective material / sealing material (sealing) Resin layer) / solar cell element / encapsulant (encapsulating resin layer) / lower protective material, sandwiched from both sides of the solar cell element by a sealing multilayer body (see FIG. 1), lower protection A solar cell element formed on the inner peripheral surface of the upper protective material, for example, a fluororesin, having a structure in which a sealing material and an upper protective material are formed on the solar cell element formed on the inner peripheral surface of the material Sputtering amorphous solar cell element on transparent protective material In such over those made having a configuration such as to form a sealing material and a lower protective material can be exemplified. In the solar cell module using the solar cell multilayer body of the present invention, when the sealing material is used at two or more sites, the solar cell multilayer body of the present invention may be used at all sites. Or the multilayer body for solar cells of the present invention may be used in only one part. Further, when the sealing material is used in two or more parts, the resin layer (I) and the resin layer (II) constituting the solar cell multilayer body of the present invention used in each part are constituted. The composition of the resin composition and the thickness ratio of the resin layer (I) and the resin layer (II) in the sealing multilayer body may be the same or different. In any case, when the solar cell element is sealed by producing the solar cell module so that the resin layer (I) side of the solar cell multilayer body of the present invention is in contact with the solar cell element side. Sufficient adhesion and sealing properties can be obtained.

  Examples of solar cell elements arranged and wired between sealing resin layers include III-V such as single crystal silicon type, polycrystalline silicon type, amorphous silicon type, gallium-arsenic, copper-indium-selenium, cadmium-tellurium, etc. Group, II-VI compound semiconductor type, dye-sensitized type, organic thin film type, and the like.

  About each member which comprises the solar cell module produced using the multilayer body for solar cells of this invention, although it does not specifically limit, As an upper protective material, glass, an acrylic resin, a polycarbonate, polyester, for example Examples thereof include a plate material such as a fluorine-containing resin and a single layer or multilayer protective material for a film. The lower protective material is a single layer or multilayer sheet such as metal or various thermoplastic resin films, for example, metals such as tin, aluminum and stainless steel, inorganic materials such as glass, polyester, inorganic vapor deposition polyester, fluorine-containing resin. And a single-layer or multilayer protective material such as polyolefin. The surface of these upper and / or lower protective materials may be subjected to a known surface treatment such as a primer treatment or a corona treatment in order to improve the adhesion with the solar cell multilayer body of the present invention or other members. it can. In addition, the solar cell multilayer body of the present invention is mainly used for protecting solar cell elements, such as improvement of flexibility, adjustment of thickness, securing of a dielectric breakdown voltage as a whole solar cell module, etc. It is also possible to use it for the part which does not adhere to a solar cell element for the purpose.

  The upper protective material / sealing material (sealing resin layer) / solar cell element / sealing material (sealing resin layer) / lower part described above for the solar cell module produced using the solar cell multilayer body of the present invention A description will be given by taking, as an example, a configuration in which a solar cell element is sandwiched by sealing materials from both sides, such as a protective material. As shown in FIG. 1, in order from the sunlight receiving side, a transparent substrate 10, a sealing resin layer 12A using the multilayer body for solar cell of the present invention, solar cell elements 14A and 14B, and a multilayer body for solar cell of the present invention. The sealing resin layer 12B using the back layer 16 and the back sheet 16 are laminated, and further, a junction box 18 (a terminal box for connecting wiring for extracting electricity generated from the solar cell element to the outside) on the lower surface of the back sheet 16 Is bonded. The solar cell elements 14A and 14B are connected by a wiring 20 in order to conduct the generated current to the outside. The wiring 20 is taken out through a through hole (not shown) provided in the back sheet 16 and connected to the junction box 18.

  As a manufacturing method of the solar cell module, a known manufacturing method can be applied, and it is not particularly limited, but in general, an upper protective material, a sealing resin layer, a solar cell element, a sealing resin layer, a lower portion It has the process of laminating | stacking a protective material in order, and the process of vacuum-sucking them and carrying out thermocompression bonding. Also, batch type manufacturing equipment, roll-to-roll type manufacturing equipment, and the like can be applied.

  The solar cell module produced by using the solar cell multilayer body of the present invention is a small solar cell represented by a mobile device, a large solar cell installed on a roof or a roof, depending on the type and module shape of the applied solar cell. The battery can be applied to various uses regardless of whether it is indoors or outdoors.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, the various measured values and evaluation about the sheet | seat displayed in this specification were performed as follows. Here, the flow direction of the sheet from the extruder is called the vertical direction, and the orthogonal direction is called the horizontal direction.

(1) Crystal melting peak temperature (Tm)
Using a differential scanning calorimeter manufactured by PerkinElmer, Inc., under the trade name “Pyris1 DSC”, according to JIS K7121, about 10 mg of the sample was heated from −40 ° C. to 200 ° C. at a heating rate of 10 ° C./min. After holding at 200 ° C. for 1 minute, the temperature was lowered to −40 ° C. at a cooling rate of 10 ° C./min, and again from the thermogram measured when the temperature was raised to 200 ° C. at a heating rate of 10 ° C./min ( Tm) (° C.) was determined.

(2) Crystallization peak temperature (Tc)
Using a differential scanning calorimeter manufactured by PerkinElmer, Inc., under the trade name “Pyris1 DSC”, according to JIS K7121, about 10 mg of the sample was heated from −40 ° C. to 200 ° C. at a heating rate of 10 ° C./min. After maintaining at 200 ° C. for 1 minute, the crystallization peak temperature (° C.) was determined from the thermogram measured when the temperature was lowered to −40 ° C. at a cooling rate of 10 ° C./min.

(3) Heat of crystal melting (ΔHm)
Using a differential scanning calorimeter manufactured by PerkinElmer Co., Ltd., trade name “Pyris1 DSC”, according to JIS K7122, about 10 mg of the sample was heated from −40 ° C. to 200 ° C. at a heating rate of 10 ° C./min. After holding at 200 ° C. for 1 minute, the temperature was lowered to −40 ° C. at a cooling rate of 10 ° C./min, and again from the thermogram measured when the temperature was raised to 200 ° C. at a heating rate of 10 ° C./min (ΔHm ) (J / g).

(4) Softening temperature (Ts)
The softening temperature of the olefin compatible resin (E) was determined according to JIS K2207.

(5) Molecular weight distribution index (Mw / Mn)
A weight average molecular weight (Mw) and a number average molecular weight (Mn) were measured using a high temperature GPC system manufactured by Nippon Water Co., Ltd., and a molecular weight distribution index (Mw / Mn) was calculated.

(6) Transparency (total light transmittance)
Using a “reflectance / transmittance meter” manufactured by Murakami Color Research Laboratory Co., Ltd., the total light transmittance of a sample having a thickness of 0.3 mm was measured according to JIS K7105. A sample having a total light transmittance of 85% or more was regarded as acceptable.

(7) Moisture resistance (water vapor transmission rate)
Based on JIS K7129B, using a PERMATRAN W 3/31 manufactured by MOCON, water vapor permeability was measured for a sample having a thickness of 0.3 mm in an atmosphere of 40 ° C. and 90% RH. A water vapor transmission rate of 3.0 g / (m ² · 24 hours) or less and exceeding 1.0 g / (m ² · 24 hours) is taken as (◯) and 1.0 g / (m ² · 24 hours) The following are (（), and those exceeding 3.0 g / (m ² · 24 hours) are (x).

(8) Rigidity (Storage elastic modulus (E '))
Using a dynamic viscoelasticity measuring device (product name: viscoelastic spectrometer DVA-200, manufactured by IT Measurement Co., Ltd.), vibration frequency: 10 Hz, temperature rising rate: 3 ° C./min, strain 0.1% Then, the storage elastic modulus (E ′) was measured from −100 ° C., and the storage elastic modulus (E ′) at 20 ° C. was read from the obtained data. Those having a storage elastic modulus (E ′) at 20 ° C. of 100 MPa or more and 1000 MPa or less were accepted.

(9) Sealing property Using a vacuum laminator (trade name: LM30 × 30, manufactured by NPC Corporation), hot plate temperature: 150 ° C., processing time: 20 minutes (breakdown, vacuuming: 5 minutes) , Press: 5 minutes, pressure retention: 10 minutes), pressure bonding speed: 3 mm thick white glass (trade name: Solite, manufactured by Asahi Glass Co., Ltd.), 0.3 mm thick sealing in order from the hot plate side under rapid conditions Material, 0.4 mm thick solar cell (manufactured by France Photowatt Co., Ltd., trade name: 101 × 101 MM), 0.3 mm thick sealing material, 0.125 mm thick weather-resistant PET film (manufactured by Toray Industries, Inc., trade name: The appearance of a solar cell module (size: 150 mm × 150 mm) produced by vacuum pressing five layers of Lumirror X10S was visually observed, and the results were evaluated according to the following criteria.
(◯) The sealing material is sufficiently wound around the solar cell element without a gap.
(X) The sealing material does not sufficiently wrap around the solar cell element, and bubbles and floats are generated.

(10) Heat resistance A sheet-like sealing material having a thickness of 0.3 mm between white plate glass having a thickness of 3 mm (size: length 75 mm, width 25 mm) and an aluminum plate having a thickness of 5 mm (size: length 120 mm, width 60 mm). Using a vacuum press machine, a sample that was laminated and pressed at 150 ° C. for 15 minutes was prepared, and the sample was installed at an inclination of 60 ° in a constant temperature and humidity chamber of 85 ° C. and 85% RH. The state after the lapse of time was observed and evaluated according to the following criteria.
(○) Glass did not deviate from the initial reference position (×) Glass deviated from the initial reference position, or the sheet melted

<Materials used>
[Ethylene-α-olefin random copolymer (A)]
(A) -1: ethylene-octene random copolymer (manufactured by Dow Chemical Co., Ltd., trade name: engage 8200, ethylene / octene = 76/24 mass% (93/7 mol%), crystal melting peak temperature = 65 ° C., heat of crystal fusion = 53 J / g)
(A) -2: ethylene-propylene-hexene random copolymer (manufactured by Nippon Polyethylene Co., Ltd., trade name: kernel KJ640T, ethylene / propylene / hexene = 80/10/10% by mass (89/7/4 mol%) ), Crystal melting peak temperature = 53 ° C., crystal melting heat amount = 58 J / g)

[Ethylene-α-olefin block copolymer (B)]
(B) -1: ethylene-octene block copolymer (manufactured by Dow Chemical Co., Ltd., trade name: Infuse 9000, ethylene / octene = 65/35 mass% (88/12 mol%), crystal melting peak temperature = 122 ° C., heat of crystal fusion = 44 J / g)

[Ethylene polymer (C)]
(C) -1: ethylene-butene-octene random copolymer (manufactured by Asahi Kasei Corporation, trade name: Creolex K4125, ethylene / butene-1 / octene-1 = 97.7 / 1.1 / 1.2 Mass% (99.1 / 0.6 / 0.3 mol%), density = 0.941 g / cm ³ , crystal melting peak temperature = 130 ° C., crystal melting heat amount = 183 J / g, crystallization peak temperature = 113 ° C. Mw / Mn = 3.12)
(C) -2: ethylene-butene-octene random copolymer (manufactured by Asahi Kasei Corporation, trade name: Creolex K4750, ethylene / butene-1 / octene-1 = 97.9 / 0.8 / 1.3 Mass% (99.3 / 0.4 / 0.3 mol%), density = 0.947 g / cm ³ , crystal melting peak temperature = 131 ° C., crystal melting heat amount = 181 J / g, crystallization peak temperature = 113 ° C. Mw / Mn = 2.87)
(C) -3: ethylene homopolymer (manufactured by Asahi Kasei Co., Ltd., trade name: Suntech HD F371, ethylene = 100 mass% (100 mol%), density = 0.944 g / cm ³ , crystal melting peak temperature = 131 C, heat of crystal fusion = 167 J / g, crystallization peak temperature = 114 ° C, Mw / Mn = 4.72)
(C) -4: ethylene-hexene random copolymer (manufactured by Ube Maruzen Polyethylene Co., Ltd., trade name: Umerit 2040FC, density = 0.918 g / cm ³ , crystal melting peak temperature = 121 ° C., heat of crystal melting = 134 J / G, crystallization peak temperature = 105 ° C., Mw / Mn = 2.80)

[Crystal nucleating agent (D)]
(D) -1: fatty acid metal salt (zinc stearate / 1,2-cyclohexanedicarboxylic acid calcium salt = 34/66 mass%)

[Olefin compatible resin (E)]
(E) -1: Hydrogenated petroleum resin (Arakawa Chemical Industries, Ltd., trade name: Alcon P115, softening temperature Ts (E) = 115 ° C.)
(E) -2: Hydrogenated petroleum resin (Arakawa Chemical Industries, Ltd., trade name: Alcon P140, softening temperature Ts (E) = 140 ° C.)

[Cyclic olefin resin (F)]
(F) -1: Cyclic olefin resin (manufactured by Polyplastics Co., Ltd., trade name: TOPAS 9506F-04, glass transition temperature = 68 ° C., amorphous (heat of crystal melting = 0 J / g))

[Additive (G)]
(G) -1: Silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM503, γ-methacryloxypropyltrimethoxysilane)

Example 1
After dry blending (A) -1, (B) -1, and (G) -1 at a mixing mass ratio of 94.5: 5: 0.5, using a φ40 mm co-directional twin screw extruder Extrusion was performed at a set temperature of 190 to 200 ° C. as a resin layer (I) serving as both outer layers from a two-type, three-layer multi-manifold die. At the same time, after dry blending (C) -1 and (D) -1 at a mixing mass ratio of 99.9: 0.1, an intermediate layer is formed from the same die using a φ40 mm co-directional twin screw extruder. The resulting resin layer (II) was extruded at a set temperature of 200 to 220 ° C. At this time, the thickness of each layer is such that the resin layer (I) / resin layer (II) / resin layer (I) is 0.1 / 0.1 / 0.1 (mm). Adjusted. Next, this coextruded sheet was quenched with a cast roll of about 20 ° C. to obtain a multilayer sheet having a thickness of 0.3 mm. The obtained multilayer sheet was evaluated for transparency, water vapor transmission rate, and heat resistance. The results are shown in Table 1.

(Example 2)
In Example 1, (C) -1, (D) -1 and (E) -1 were mixed in a resin mass (79.9: 0.1: 20) constituting the resin layer (II). A multilayer sheet was produced and evaluated by the same method and thickness structure as in Example 1 except that the mixture was mixed at a ratio. The results are shown in Table 1.

(Example 3)
In Example 1, the resin composition constituting the resin layer (II) was prepared by mixing (C) -1, (D) -1, (E) -1, and (F) -1 with a mixing mass ratio of 49.9: A multilayer sheet was prepared and evaluated by the same method and thickness as in Example 1 except that the mixture was mixed at a ratio of 0.1: 20: 30. The results are shown in Table 1.

Example 4
In Example 3, except that (C) -1 in the resin composition constituting the resin layer (II) was changed to (C) -2, production of a multilayer sheet with the same method and thickness as in Example 1, Evaluation was performed. The results are shown in Table 1.

(Example 5)
In Example 3, except that (C) -1 in the resin composition constituting the resin layer (II) was changed to (C) -3, production of a multilayer sheet with the same method and thickness as in Example 1, Evaluation was performed. The results are shown in Table 1.

(Example 6)
In Example 3, except that (A) -1 in the resin composition constituting the resin layer (I) was changed to (A) -2, production of a multilayer sheet with the same method and thickness as in Example 1, Evaluation was performed. The results are shown in Table 1.

(Example 7)
In Example 1, except that (C) -1 in the resin composition constituting the resin layer (II) was changed to (C) -4, a multilayer sheet was produced by the same method and thickness as in Example 1. And evaluated. The results are shown in Table 1.

(Example 8)
In Example 3, a multilayer sheet was produced by the same method and thickness as in Example 3 except that (E) -1 in the resin composition constituting the resin layer (II) was changed to (E) -2. And evaluated. The results are shown in Table 1.

Example 9
After dry blending (A) -1, (B) -1, and (G) -1 at a mixing mass ratio of 94.5: 5: 0.5, using a φ40 mm co-directional twin screw extruder The resin layer (I) was extruded at a set temperature of 190 to 200 ° C. from a two-type, two-layer multi-manifold die. At the same time, after dry blending (C) -1, (D) -1, (E) -1, and (F) -1 at a mixing mass ratio of 49.9: 0.1: 20: 30 The resin layer (II) was extruded from the same die at a set temperature of 200 to 220 ° C. using a φ40 mm same-direction twin screw extruder. At this time, the discharge amount of the molten resin was adjusted so that the thickness of each layer was 0.15 / 0.15 (mm) of resin layer (I) / resin layer (II). Next, this coextruded sheet was quenched with a cast roll of about 20 ° C. to obtain a multilayer sheet having a thickness of 0.3 mm. Evaluation similar to Example 1 was performed about the obtained multilayer sheet. The results are shown in Table 1.

(Comparative Example 1)
In Example 1, a multilayer sheet was prepared and evaluated by the same method and thickness as in Example 1 except that (C) -1 was used alone as the resin composition constituting the resin layer (II). The results are shown in Table 1.

(Comparative Example 2)
In Example 1, (C) -1 in the resin composition constituting the resin layer (II) was manufactured by Prime Polymer Co., Ltd., trade name: Hi-Zex 3600F (high density polyethylene, ethylene = 100% by mass (100 mol) %), Density = 0.958 g / cm ³ , crystal melting peak temperature = 134 ° C., heat of crystal melting = 195 J / g, crystallization peak temperature = 116 ° C., Mw / Mn = 4.72, hereinafter (N) −1 A multilayer sheet was produced and evaluated in the same manner and in the same manner as in Example 1 except that it was changed to (abbreviated). The results are shown in Table 1.

(Comparative Example 3)
In Example 1, except having changed the resin composition which comprises resin layer (I) into what mixed (A) -1 and (G) -1 by mixing mass ratio 99.5: 0.5. A multilayer sheet was prepared and evaluated by the same method and thickness structure as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
In Example 1, the resin layer (I) was eliminated, and a single-layer sheet having a thickness of 0.3 mm consisting only of the resin layer (II) was obtained. Table 1 shows the results of evaluating the obtained sheet in the same manner as in Example 1.

(Reference Example 1)
In Example 1, the resin layer (II) was eliminated, and a single-layer sheet having a thickness of 0.3 mm consisting only of the resin layer (I) was obtained. Table 1 shows the results of evaluating the obtained sheet in the same manner as in Example 1.

  As is clear from Table 1, the multilayer body for solar cell of the present invention shown in Examples 1 to 9 is excellent in all of moisture resistance, transparency, sealing property, handling property, and heat resistance. It was. On the other hand, the sheets of Comparative Examples 1 to 4 having compositions and configurations different from those of the present invention were inferior in at least one of moisture resistance, transparency, sealing properties, handling properties, and heat resistance.

(Example 10)
Using a vacuum laminator LM30 × 30 manufactured by NPC, hot plate temperature: 150 ° C., processing time: 20 minutes (breakdown, evacuation: 5 minutes, press: 5 minutes, pressure retention: 10 minutes), pressure bonding Speed: Under rapid conditions, in order from the hot plate side, a white sheet glass with a thickness of 3 mm (made by Asahi Glass Co., Ltd., trade name: Solite) as an upper protective material, a multilayer sheet with a thickness of 0.3 mm collected in Example 3 (Encapsulant, resin layer (I) is on the solar cell element side), 0.4 mm thick solar cell element (cell) (manufactured by Photowatt, model: 101 × 101 MM), thickness obtained in Example 3 is 0 .3 mm multilayer sheet (sealing material, resin layer (I) is on the solar cell side), 0.125 mm thick weather-resistant PET film (trade name: Lumirror X10S) as the lower protective material 5 layers are vacuum-pressed and solar cell module (Size: 150 mm × 150 mm). The obtained solar cell module was excellent in transparency and appearance.

DESCRIPTION OF SYMBOLS 10 ... Transparent substrate 12A, 12B ... Sealing resin layer 14A, 14B ... Solar cell element 16 ... Back sheet 18 ... Junction box 20 ... Wiring

Claims (13)

50-99% by mass of an ethylene-α-olefin random copolymer (A) that satisfies the following condition (a) and an ethylene-α-olefin block copolymer (B) that satisfies the following condition (b) 1 An ethylene polymer (C) having a resin layer (I) containing ˜50% by mass as at least one outermost layer and satisfying the following condition (c), and a crystal nucleating agent (D): A multilayer body for solar cells, comprising a resin layer (II) contained therein.
(A): The crystal melting heat quantity measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 0 to 70 J / g.
(B): The crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100-145 ° C., and the crystal melting heat amount is 5-70 J / g.
(C): The crystal melting peak temperature measured at a heating rate of 10 ° C./min in differential scanning calorimetry is 100 to 145 ° C., and the crystal melting heat amount is 120 to 190 J / g.   The solar cell multilayer body according to claim 1, wherein the content of the crystal nucleating agent (D) in the resin layer (II) is 0.01 mass% or more and 3 mass% or less.   The resin layer (II) contains at least one olefin-compatible resin (E) selected from the group consisting of petroleum resins, terpene resins, coumarone-indene resins, rosin resins, and hydrogenated derivatives thereof. The multilayer body for solar cells according to claim 1 or 2, wherein   Crystallization peak at which the softening temperature Ts (E) of the olefin compatible resin (E) measured based on JIS K2207 is measured at a cooling rate of 10 ° C./min in the differential scanning calorimetry of the ethylene polymer (C). It is temperature Tc (C) +5 degrees C or less, The multilayer body for solar cells of Claim 3 characterized by the above-mentioned.   The ethylene polymer (C) contains at least one α-olefin selected from butene-1, hexene-1, and octene-1 as a component other than ethylene, and the ethylene polymer ( The multilayer for solar cell according to any one of claims 1 to 4, wherein the total of the α-olefins contained in C) is 0.1 to 3.0% by mass.   The said resin layer (II) contains cyclic olefin resin (F), The multilayer body for solar cells of any one of Claim 1 to 5 characterized by the above-mentioned. The water vapor transmission rate measured at a temperature of 40 ° C. and a relative humidity of 90% based on JIS K7129B method when the solar cell multilayer body is molded to a thickness of 0.3 mm is 3.0 g / (m ² · 24 hours) or less. The multilayer body for solar cells according to any one of claims 1 to 6, wherein the multilayer body is for solar cells.   8. The total light transmittance measured according to JIS K7105 when the solar cell multilayer body is molded to a thickness of 0.3 mm is 85% or more, according to claim 1. Multilayer for solar cells.   The solar cell multilayer body according to any one of claims 1 to 8, wherein a storage elastic modulus (E ') at a vibration frequency of 10 Hz and a temperature of 20 ° C in dynamic viscoelasticity measurement is 100 to 1000 MPa. .   The resin layer (I) and / or the resin layer (II) is characterized by adding at least one additive selected from silane coupling agents, antioxidants, ultraviolet absorbers and weathering stabilizers. The multilayer body for solar cells according to any one of claims 1 to 9.   11. The multilayer body for solar cell according to claim 1, wherein a thickness ratio of the resin layer (II) in the multilayer body for solar cell is 20% or more and 70% or less. .   It is a solar cell sealing material which adhere | attaches and protects a solar cell element, The multilayer body for solar cells of any one of Claims 1-11 characterized by the above-mentioned.   The solar cell module produced using the multilayer body for solar cells of any one of Claim 1 to 12.

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