JP2012216688A - Manufacturing method of sealing material sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a sealing material sheet for a solar cell module which has small thermal contraction during modularization, a uniform film thickness, and excellent productivity.SOLUTION: A manufacturing method of a sealing material sheet for a solar cell module includes: a sheet formation process where a sealing material composition is subjected to molten molding to obtain an unprocessed sealing material sheet which has not been annealed; a laminate process where the unprocessed sealing material sheet is crimped and bonded to a strippable support base material to obtain a laminate body; an annealing process where heat treatment is performed after the laminate process; and a peeling process where the strippable support base material is peeled from the laminate body after the annealing process.

Description

  The present invention relates to a method for producing a sealing material sheet for a solar cell module, and more particularly to a method for producing a sealing material sheet having a small thermal shrinkage during vacuum heating lamination in a modularization process.

  In recent years, solar cells as a clean energy source have attracted attention due to the growing awareness of environmental issues. Currently, various types of solar cell modules have been developed and proposed. Generally, a solar cell module has a configuration in which a transparent front protective substrate, a solar cell element, and a back sheet are laminated via a sealing material sheet.

  As a sealing material sheet of a solar cell module, the structure which mainly contains EVA (ethylene-vinyl acetate copolymer) from the surface of transparency or fluidity | liquidity and contains a crosslinking agent and a crosslinking adjuvant is known. In this case, the above composition is molded in an uncrosslinked state and crosslinked by heating in the modularization step or heating in another crosslinking step.

  However, since EVA has a significant thermal shrinkage at the time of crosslinking, there is a problem that the solar cell element breaks during vacuum heating lamination due to this shrinkage stress. In particular, in recent years, the thickness of solar cell elements tends to be as thin as 0.2 mm or less, and this thermal shrinkage is a more significant problem than ever before.

  In order to prevent this thermal shrinkage of EVA, it is known that annealing for stress relaxation is effective. For example, Patent Document 1 below discloses that the thermal contraction rate can be reduced by performing an annealing process at a temperature about 20 ° C. to 25 ° C. higher than the softening point immediately after the EVA film formation and before the softening point or lower. ing.

  Further, in Patent Document 2 below, in order to prevent thermal shrinkage in the modularization process, it is disclosed that a sealing material is melt-extruded and formed on a backsheet substrate, immediately cooled after being pressurized, and wound up. ing.

JP 2000-84996 A JP 2011-20375 A

  The annealing process of Patent Document 1 is a process in which an annealing process is continuously performed in-line immediately after melting. In this case, non-uniformity and undulations occur in the thickness in the width direction due to uneven resin flow during die extrusion. Further, in-line, the annealing process becomes a rate-determining step, and productivity is lowered. For this reason, further improvements have been required both in terms of quality and productivity.

  Since the low shrinkage resin film of Patent Document 2 does not require an annealing process in the first place, the annealing process is not performed. In this case, the stress relaxation is insufficient only by melt-extrusion of the sealing material and spreading on the base material, and the shrinkage rate cannot be sufficiently reduced with a sealing material having a high thermal shrinkage rate. Specifically, in recent years, polyethylene resin or the like may be used as the sealing material resin in addition to EVA. In this case, the MFR at the extrusion temperature may be low. In this case, the residual internal stress is very high and the thermal shrinkage rate is also high. Therefore, the residual strain is sufficiently removed without the annealing treatment as in Patent Document 2. Can not.

  Although it is conceivable to perform the annealing process again after the sealing material is integrated with the back sheet, the high temperature in the annealing process may damage the low-melting-point material constituting the back sheet. In addition, when the winding after integrating the back sheet with poor thermal conductivity is rewound again and annealed, the sealing material near the bonding interface becomes insufficiently annealed to prevent physical properties from being deteriorated. In addition, there is a problem that an extra time is required for the annealing process.

  The present invention has been made in order to solve the above problems, and its purpose is to sufficiently suppress thermal shrinkage, to have a uniform film thickness, and to be excellent in productivity, for a solar cell module. It is in providing the manufacturing method of.

  As a result of examining the annealing method of the encapsulant sheet, the present inventors have found that the encapsulant sheet and the encapsulant sheet have a releasability that is less than or equal to a predetermined peel force. It was found that the above-mentioned problems can be solved by performing an annealing treatment after being bonded to each other and then peeling off the peelable support substrate, thereby completing the present invention. More specifically, the present invention provides the following.

(1) A sheet forming step for obtaining an untreated sealing material sheet that has not been annealed by melt-molding the sealing material composition;
A laminating step in which the untreated sealing material sheet and the releasable support base material are pressure-bonded and bonded to obtain a laminate;
An annealing treatment step after the laminating step;
A method for producing a sealing material sheet for a solar cell module, comprising: a peeling step of peeling the peelable support substrate from the laminate after the annealing treatment step.

  (2) The peelable support base material has a peel strength between the polyester base and the acrylic pressure-sensitive adhesive tape of 1.5 N / 25 mm or less under measurement conditions of 180 ° C. peeling and a peeling speed of 50 mm / min. 1) The manufacturing method of the sealing material sheet | seat of description.

  (3) The method for producing a sealing material sheet according to (1) or (2), wherein the peelable support substrate includes a silicone resin layer or a fluororesin layer on at least the surface to be pressure-bonded.

  (4) The encapsulant composition is an ethylene-polar monomer copolymer resin containing a crosslinking agent, and the MFR at 190 ° C. of the encapsulant composition is 10 g / 10 min or more and 40 g / 10 min or less. The manufacturing method of the sealing material sheet in any one of (1) to (3).

  (5) The encapsulant composition is a polyethylene resin containing a crosslinking agent, and the MFR of the encapsulant composition at 190 ° C. is 0.1 g / 10 min or more and 1.0 g / 10 min or less ( The manufacturing method of the sealing material sheet in any one of (1) to (3).

(6) The temperature in the annealing treatment step is
The method for producing a sealing material sheet according to (5), wherein the melting point of the polyethylene-based resin is in the range of 90 ° C. to 150 ° C.

(7) A sealing material sheet for a solar cell module that has been subjected to an annealing treatment after melt molding the sealing material composition,
The sealing material composition is a polyethylene resin containing a crosslinking agent,
The MFR at 190 ° C. of the sealing material composition is 0.1 g / 10 min or more and 1.0 g / 10 min or less,
The film thickness change in the TD direction of the encapsulant sheet is within 5% of the average thickness,
Shrinkage of test piece side length in MD direction before and after heating after placing test piece of sealing material film of 100 mm × 100 mm in the sealing material sheet on talc plate heated to 150 ° C. and allowing to stand for 10 minutes. The sealing material sheet characterized by the heat shrinkage rate which is a ratio being 30% or less.

  According to the method for manufacturing a sealing material sheet for a solar cell module of the present invention, manufacturing of a sealing material sheet for a solar cell module that can sufficiently suppress thermal shrinkage, has a uniform film thickness, and is excellent in productivity. Can provide a method.

It is a graph which shows the measurement result of the film thickness change in the case with a peelable support base material in an Example. It is a graph which shows the measurement result of the film thickness change in the case of no peeling support base material in an Example.

[Encapsulant composition]
The sealing material composition contains a crosslinking agent in the base resin. In this system, since it is necessary to extrude at a temperature lower than the thermal decomposition temperature of the crosslinking agent, the MFR at the time of melt extrusion decreases, the resin becomes hard, internal strain accumulates, and the thermal shrinkage rate increases. Examples of the heat shrinkage rate of the untreated sealing material sheet before the annealing treatment include 40% or more and 70% or less, and the heat shrinkage rate is set to 30% or less by the annealing treatment described later.

[Base resin]
The base resin is, for example, a polyolefin-based resin, and is not particularly limited as long as it is composed of an olefin monomer. Accordingly, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) which is a copolymer of ethylene and α-olefin, ethylene-vinyl acetate copolymer (EVA), etc. included. Hereinafter, a polyethylene-based resin and an ethylene-polar monomer copolymer as a preferable base resin, and more specifically, an EVA resin will be described.

[Polyethylene resin]
In the present invention, low density polyethylene (LDPE) having a density of 0.940 or less, preferably linear low density polyethylene (LLDPE) is used. Linear low density polyethylene is a copolymer of ethylene and α- olefin, in the present invention, within the scope thereof density of 0.940 g / cm ³ or less, preferably 0.900 g / cm ³ within the following ranges More preferably, it is the range of 0.870-0.890 g / cm < ³ >.

  In the present invention, it is preferable to use a metallocene linear low density polyethylene. Metallocene linear low density polyethylene is synthesized using a metallocene catalyst which is a single site catalyst. Such polyethylene has few side chain branches and a uniform comonomer distribution. For this reason, molecular weight distribution is narrow, it is possible to make it the above ultra-low density, and a softness | flexibility can be provided with respect to the sealing material for solar cell modules. In addition, since the metallocene-based linear low density polyethylene has a narrow crystallinity distribution and a uniform crystal size, not only a large crystal size does not exist, but also the crystallinity itself is low due to the low density. For this reason, it is excellent in transparency when processed into a sheet shape. Therefore, even if the sealing material which consists of a sealing material composition for solar cell modules of this invention is arrange | positioned between a transparent front substrate and a solar cell element, electric power generation efficiency hardly falls.

  As the α-olefin of the linear low density polyethylene, an α-olefin having no branch is preferably used. Among these, 1-hexene and 1-heptene which are α-olefins having 6 to 8 carbon atoms are preferable. Or 1-octene is particularly preferably used. When the α-olefin has 6 to 8 carbon atoms, the solar cell module sealing material can be provided with good flexibility and good strength.

  Further, the melt mass flow rate (MFR) of the linear low density polyethylene is preferably 0.5 g / 10 min or more and 40 g / 10 min or less at 190 ° C. in the JIS K7210 method, and is 2 g / 10 min or more and 40 g / 10 min or less. More preferably. When the MFR is in the above range, the adhesion between the transparent substrate made of glass or the like and the solar cell module sealing material is excellent.

  The “polyethylene resin” in the present invention includes not only ordinary polyethylene obtained by polymerizing ethylene, but also a resin obtained by polymerizing a compound having an ethylenically unsaturated bond such as α-olefin. Examples include resins obtained by copolymerizing a plurality of different compounds having an ethylenically unsaturated bond, and modified resins obtained by grafting different chemical species to these resins.

  Among these, a silane-modified resin obtained by grafting an ethylenically unsaturated silane compound on at least an α-olefin can be preferably used. By using such a resin, adhesion between a sealing material and a member such as a transparent front substrate or a solar cell element can be obtained.

  The silane-modified resin is described in, for example, Japanese Patent Application Laid-Open No. 2003-46105. By using the copolymer as a component of the solar cell module filler composition, it has excellent strength, durability, etc., and weather resistance, heat resistance, water resistance, light resistance, wind pressure resistance, yield resistance, It has excellent other characteristics, and has excellent heat-sealability without being affected by manufacturing conditions such as thermocompression bonding for manufacturing solar cell modules. It is stable, low-cost, and can be used in various applications. A suitable solar cell module can be manufactured.

  The silane-modified resin is a copolymer obtained by copolymerizing at least an α-olefin and an ethylenically unsaturated silane compound as a comonomer and, if necessary, further using another unsaturated monomer as a comonomer. A modified body or a condensate is also included.

Specifically, for example, one or more of α-olefins, one or more of ethylenically unsaturated silane compounds, and, if necessary, one or more of other unsaturated monomers. Using a desired reaction vessel, for example, pressure 500-4000 Kg / cm ² position, preferably, 1000-4000 Kg / cm ² position, temperature 100-400 ° C., preferably 150-350 ° C. In the presence of a radical polymerization initiator and, if necessary, a chain transfer agent, random copolymerization is performed simultaneously or stepwise, and if necessary, a random copolymer formed by the copolymerization is formed. A silane compound portion can be modified or condensed to produce a copolymer of an α-olefin and an ethylenically unsaturated silane compound, or a modified or condensed product thereof.

  The content of the ethylenically unsaturated silane compound when constituting the copolymer of the α-olefin and the ethylenically unsaturated silane compound is, for example, about 0.001 to 15% by mass relative to the total copolymer mass. Preferably, about 0.01 to 5 mass%, particularly preferably about 0.05 to 2 mass% is desirable. In the present invention, when the content of the ethylenically unsaturated silane compound constituting the copolymer of the α-olefin and the ethylenically unsaturated silane compound is large, the mechanical strength and heat resistance are excellent, but the content is excessive. When it becomes, it exists in the tendency which is inferior to tensile elongation, heat-fusibility, etc.

[EVA resin]
EVA resin can also be used as the base resin in the present invention. Conventionally known materials can be used and are not particularly limited. However, the vinyl acetate content (VA content) is 20% by mass to 40% by mass, preferably 25% by mass to 35% by mass, and more preferably 28% by mass to 33%. It is preferable from the point of obtaining a heat resistance of 100 ° C. or more and 150 ° C. or less due to a high degree of crosslinking by a high gel fraction after the vacuum heating lamination step of the solar cell production step.

  The melt mass flow rate (MFR) of the EVA resin is preferably 1 g / 10 min or more and 40 g / 10 min or less, more preferably 15 g / 10 min or more and 40 g / 10 min or less at 190 ° C. in JIS K7210 method. The Vicat softening point of JIS K7206 is preferably in the range of 30 ° C to 40 ° C. When the MFR and softening point are within the above ranges, the resin is excellent in the property of being melted by heating, uniformly fluidized with the additive, and deformed to a constant shape until cooling.

[Crosslinking agent]
A well-known thing can be used for a crosslinking agent, It does not specifically limit, For example, a well-known radical polymerization initiator can be used. Examples of radical polymerization initiators include hydroperoxides such as diisopropylbenzene hydroperoxide and 2,5-dimethyl-2,5-di (hydroperoxy) hexane; di-t-butyl peroxide, t-butyl Cumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-peroxy) hexyne-3, etc. Dialkyl peroxides; diacyl peroxides such as bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dichlorobenzoyl peroxide; t-butyl peroxyacetate, t-butyl pero Ci-2-ethylhexanoate, t-butyl peroxypivalate, t-butyl peroxyoctoate, t-butyl peroxyisopropyl carbonate, t-butyl peroxybenzoate, di-t-butyl peroxyphthalate, 2 , 5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexyne-3, t-butylperoxy-2-ethylhexyl carbonate Oxyesters; organic peroxides such as methyl peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide, or azo compounds such as azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile), dibutyltin Diacetate, Dibutyltin dilaurate , It may be mentioned dibutyltin dioctoate, dioctyltin dilaurate, dicumyl peroxide, such a silanol condensation catalyst. As content of a crosslinking agent, it is preferable that 0.01 mass%-2 mass% are contained in a composition, More preferably, it is the range of 0.05 mass%-1.5 mass%.

[Crosslinking aid]
In addition to the above crosslinking agent, a crosslinking aid may be used as necessary. The crosslinking aid is preferably a polyfunctional monomer having a carbon-carbon double bond and / or an epoxy group, and more preferably the functional group of the polyfunctional monomer is an allyl group, a (meth) acrylate group, or a vinyl group. This promotes an appropriate crosslinking reaction to improve the adhesion between the solar cell module sealing material and the transparent front substrate such as glass. In the present invention, the crosslinking aid is a linear low density polyethylene. The crystallinity is reduced and transparency is maintained.

  Specifically, polyallyl compounds such as triallyl isocyanurate (TAIC), triallyl cyanurate, diallyl phthalate, diallyl fumarate, diallyl maleate, trimethylolpropane trimethacrylate (TMPT), trimethylolpropane triacrylate (TMPTA) Poly (meth) acryloxy compounds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, Glycidyl methacrylate containing epoxy groups, 4-hydroxybutyl acrylate glycidyl ether and 1,6-hexanediol diglycidyl ether containing two or more epoxy groups, 1 4-butanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, and epoxy compounds such as trimethylolpropane polyglycidyl ether. These may be used alone or in combination of two or more.

  Among the above-mentioned crosslinking aids, TAIC is preferable from the viewpoint of having the above-mentioned adhesion, good compatibility with low-density polyethylene, reducing crystallinity by crosslinking and maintaining transparency, and imparting flexibility at low temperatures. Can be used.

  The amount of the crosslinking aid used is preferably 0.01 to 3% by mass, more preferably 0.05 to 2.0 parts by mass in the composition. Within this range, an appropriate crosslinking reaction can be promoted to improve the adhesion between a transparent substrate made of glass or the like and the solar cell module sealing material.

[Radical absorbent]
In the encapsulant composition for solar cell modules of the present invention, the degree of crosslinking can be adjusted by using the above-mentioned crosslinking auxiliary agent serving as a radical polymerization initiator and the radical absorbent for quenching it together. it can. Examples of such radical absorbers include hindered phenol-based antioxidants, hindered amine-based weather resistance stabilization, and the like. A hindered phenol-based radical absorbent having a high radical absorbing ability near the crosslinking temperature is preferred. It is preferable that the usage-amount of a radical absorber is contained in 0.01 to 3 mass% in a composition, More preferably, it is the range of 0.05 mass part-2.0 mass parts. If it exists in this range, a crosslinking reaction can be suppressed moderately and the adhesiveness of a transparent substrate and the sealing material for solar cell modules can be improved.

[Other ingredients]
The solar cell module sealing material composition may further contain other components. For example, a weather resistance masterbatch for imparting weather resistance to the encapsulant prepared from the encapsulant composition for solar cell modules of the present invention, various fillers, light stabilizers, ultraviolet absorbers, heat stabilizers, etc. These components are exemplified. These contents vary depending on the particle shape, density, and the like, but are preferably in the range of 0.001 to 5 mass% in the solar cell module encapsulant composition. By including these additives, it is possible to impart a long-term stable mechanical strength, an effect of preventing yellowing, cracking, and the like to the encapsulant composition for solar cell modules.

  The weather-resistant masterbatch is a dispersion of a light stabilizer, a UV absorber, a heat stabilizer, the above-mentioned antioxidant, etc., in a resin such as polyethylene, and this is a sealing material composition for a solar cell module. By adding to, favorable weather resistance can be imparted to the solar cell module sealing material. The weatherproof masterbatch may be prepared and used as appropriate, or a commercially available product may be used. The resin used in the weatherproof masterbatch may be a linear low density polyethylene used in the present invention, or other resins described above.

  These light stabilizers, ultraviolet absorbers, heat stabilizers and antioxidants can be used alone or in combination of two or more.

  Furthermore, as other components used in the solar cell module sealing material composition of the present invention, in addition to the above, an adhesion improver, a nucleating agent, a dispersing agent, a leveling agent, a plasticizer, an antifoaming agent, a flame retardant, and the like. Can be mentioned.

<Sealing material sheet>
[Sheet making process]
The untreated encapsulant sheet in the present invention is obtained by, for example, molding the above encapsulant composition by a conventionally known method, and is formed into a sheet or film, and is subjected to an annealing treatment. It means a sheet that is not. In addition, the sheet form in this invention means the film form, and there is no difference in both.

  The sheet forming step of the encapsulant composition is performed by various molding methods such as injection molding, extrusion molding, hollow molding, compression molding, and rotational molding, which are used in ordinary thermoplastic resins.

  The sealing material composition used in the present invention contains a cross-linking agent, and is difficult to extrude at a temperature higher than the decomposition temperature of the cross-linking agent. For this reason, the MFR at the extrusion temperature decreases and internal strain remains, which causes a large heat shrinkage. As an example, in the case of the polyethylene-based resin containing the cross-linking agent, the MFR at 190 ° C. of the sealing material composition is 0.1 g / 10 min or more and 1.0 g / 10 min or less. When the encapsulant composition is an ethylene-vinyl acetate copolymer resin containing a crosslinking agent, the MFR at 190 ° C. of the encapsulant composition is 10 g / 10 min or more and 40 g / 10 min or less. In this case, the heat shrinkage rate is 40% to 70% in the molded sealing material sheet.

[Annealing process]
With such a high heat shrinkage rate, defects such as delamination of the sealing material due to heat shrinkage in the modularization process and cutting of the tab wire which is a conductive wire connecting the cells occur. For this reason, an annealing process is performed.

  Here, in the present invention, the unprocessed sealing material sheet and the releasable support base material are bonded together by pressure bonding, a laminating step for obtaining a laminate, an annealing treatment step after the laminating step, annealing And a peeling step of peeling the peelable support substrate from the laminate after the treatment step.

  The peelable support substrate preferably has a peel force of 1.5 N / 25 mm or less under measurement conditions of 180 ° C. peel at a tape peel strength test and a peel rate of 50 mm / min. Here, the temperature is preferably 23 ° C. The tape used here is a measured value after using a product name 31B tape manufactured by Nitto Denko Corporation, leaving a roll with a load of 2 kg in one reciprocation, and leaving it for 2 hours.

  Although a specific peelable support substrate is appropriately selected depending on the type of the untreated sealing material sheet, it needs to have heat resistance at the annealing temperature. Preferably, it is a release film having a silicone resin layer or a fluororesin layer on at least the surface to be pressure-bonded. More specifically, a release PET film or ETFE film (exfoliated with a silicone resin or a fluororesin on the surface) Examples thereof include an ethylene-tetrafluoroethylene copolymer film). For example, when the sealing material composition is EVA containing a crosslinking agent, a normal PET film can also be used.

  The peelable support substrate and the untreated sealing material sheet are pressed and integrated by, for example, passing a nip roll or the like to form a laminate. At this stage, it is temporarily attached and its strength is sufficiently small. The laminating step in the present invention may be performed off-line separately from the sheeting step, or may be performed continuously inline following the sheeting step.

  Next, an annealing process is performed in this state. As the annealing treatment means, any conventionally known heat treatment means can be used and is not particularly limited. As an example of the annealing treatment temperature, when the sealing material composition is a polyethylene resin containing a crosslinking agent, the melting point is in the range of + 90 ° C. to melting point + 150 ° C., more specifically in the range of 150 ° C. to 200 ° C. An example of the annealing time is 1 minute to 5 minutes. When the encapsulant composition is an EVA resin containing a crosslinking agent, the melting point is in the range of + 10 ° C. to the melting point + 60 ° C., more specifically in the range of 70 ° C. to 120 ° C., and the annealing time is from 1 minute to 5 Minutes can be exemplified.

  In the present invention, the untreated sealing material sheet is integrated on the peelable support substrate. For this reason, stress relaxation can occur uniformly on the peelable support substrate and annealing can be performed while maintaining the uniformity of the film thickness. Moreover, productivity can be improved by performing this annealing process off-line separately from the sheet forming process.

  After the annealing treatment step, the peelable support base material is peeled from the laminate, and the encapsulant sheet and the peelable support base material are separately wound up to obtain the annealed sealing material sheet. The peelable support substrate can be used again. Since the peel force of the peelable support substrate is 1.5 N / 25 mm or less by the above measurement method, the sealant sheet can be used without affecting the thickness or surface state of the sealant sheet after annealing. Obtainable.

  Thus, the sealing material sheet obtained by the manufacturing method of this invention is the said sealing material sheet on the talc plate heated at 150 degreeC, when the sealing material composition is a polyethylene-type resin containing a crosslinking agent. The heat shrinkage rate, which is the shrinkage ratio of the side length of the test piece in the MD direction before and after heating, after placing a test piece of a sealing material film of 100 mm × 100 mm in and leaving it to stand for 10 minutes is 30% or less. The MD direction is a longitudinal direction that is a discharge direction in the sheet forming process. On the other hand, when the encapsulant composition is an EVA resin containing a cross-linking agent, a test piece of a 100 mm × 100 mm encapsulant film in the encapsulant sheet is placed on a talc plate heated to 100 ° C. for 10 minutes. The thermal contraction rate, which is the contraction ratio of the test piece side length in the MD direction before and after heating, is 30% or less.

  Moreover, the film thickness change of the sealing material sheet | seat of the TD direction is less than 5% with respect to average thickness. Here, the film thickness change is a difference between the maximum thickness and the minimum thickness. The TD direction is the die width direction orthogonal to the MD direction.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.
<Example of production of untreated sealing material sheet>
[Production Example 1: Crosslinking agent-containing polyethylene resin]
20 parts by mass of the following silane-modified transparent resin, 5 parts by mass of a weather-resistant masterbatch, and 80 parts by mass of a polymerization initiator compound resin were mixed to obtain a blend for a single layer. An untreated encapsulant sheet having an average film thickness of 450 μm was prepared by using the above blend with a φ30 mm extruder and a film forming machine having a T die having a width of 200 mm at an extrusion temperature of 210 ° C. and a take-off speed of 1.1 m / min.
Silane modified transparent resin: vinyl trimethoxy with respect to 98 parts by mass of metallocene linear low density polyethylene (M-LLDPE) having a density of 0.881 g / cm ³ and an MFR at 190 ° C. of 2 g / 10 min. 2 parts by mass of silane and 0.1 part by mass of dicumyl peroxide as a radical generator (reaction catalyst) are mixed, melted and kneaded at 200 ° C., density 0.884 g / cm ³ , MFR at 190 ° C. A silane-modified transparent resin having a weight of 1.8 g / 10 min was obtained.
Weatherproof masterbatch: 3.8 parts by mass of benzophenol UV absorber and hindered amine light stabilizer 5 with respect to 100 parts by mass of powder obtained by pulverizing Ziegler linear low density polyethylene having a density of 0.880 g / cm ³ Mass parts and 0.5 parts by mass of a phosphorous heat stabilizer were mixed, melted, processed, and pelletized to obtain a master batch.
Polymerization initiator compound resin: t-amyl-peroxy-2-ethylhexyl carbonate with respect to 100 parts by mass of M-LLDPE pellets with a density of 0.880 g / cm ³ and MFR at 190 ° C. of 3.1 g / 10 min. 1 mass part was impregnated and the compound pellet was obtained.

[Production Example 2: EVA resin containing a crosslinking agent]
A cross-linking agent-containing EVA resin (VA33, MFR30) having the following composition was formed into a thickness of 400 μm by a conventional T-die method to obtain an untreated sealing material sheet. The film forming temperature was 95 to 100 ° C.
EVA resin: manufactured by Mitsui DuPont Polychemical Co., Ltd. Trade name EV150R 100 parts by weight cross-linking agent (TBEC): t-butylperoxy-2-ethylhexyl carbonate (manufactured by Arkema Yoshitomi Co., Ltd., trade name Luperox TBEC) 0.5 part by weight cross-linking agent ( 101): 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (trade name Luperox 101, manufactured by Arkema Yoshitomi Co., Ltd.) 0.5 part by weight of crosslinking aid A (TMPT): trimethylolpropane Trimethacrylate (Sartomer, trade name SR350) 1.0 part by weight Crosslinking aid B (TAIC): Triallyl isocyanurate (Sartomer, trade name SR533) 1.0 part by weight Silane coupling agent (SC agent) : Shin-Etsu Chemical Co., Ltd., trade name KBM503) 0.5 parts by weight UV Collecting agent (UV agent): Chemipro Kasei Co., Ltd., trade name KEMISORB12) 0.3 parts by weight Antioxidant A: BASF Co., Ltd., trade name Irganox 1076 0.01 parts by weight Antioxidant B: BASF Co., trade name Irganox 1330 0.01 parts by weight antioxidant C: manufactured by BASF, trade name Irganox 1010 0.01 parts by weight antioxidant D: manufactured by BASF, trade name Irgafos 168 0.03 parts by weight hindered amine light stabilizer (HALS): BASF Made by Tinuvin 770 0.1 parts by weight

<Test Example 1>
About the unprocessed sealing material sheet | seat of the said manufacture examples 1 and 2, on the conditions shown in Table 1, the lamination process, the annealing process process, and the peeling process were performed, and the sealing material sheet was obtained. Conditions 1 to 17 are the crosslinking agent-containing polyethylene resin of Production Example 1, and conditions 18 to 21 are the crosslinking agent-containing EVA resin of Production Example 2. Further, the thermal shrinkage rate (%) before and after the annealing process and the peeling force in the peeling process were evaluated. The results are shown in Table 1. The following four types were used as the peelable support substrates in the table.
PET: Toyobo Co., Ltd., product name E-5001, thickness 50 μm
Release PET (1): Silicone coating type, manufactured by Panac Co., Ltd., trade name SP-PET-03-75BU, thickness 75 μm
Exfoliated PET (2): Non-silicon type, manufactured by Panac Co., Ltd., trade name PET75TP01, thickness 75 μm
Exfoliated PET (3): Non-silicone type, manufactured by Panac Co., Ltd., trade name PET75TP03, thickness 75 μm

As described above, the five types of tape peeling force were obtained by using a product name 31B tape manufactured by Nitto Denko Corporation (a polyester adhesive tape No. 1 manufactured by Nitto Denko Corporation having an acrylic adhesive layer formed on a polyester base material). 31B), the result was measured under the measurement conditions (N / P) at 180 ° C. peeling and peeling rate of 50 mm / min after bonding with a peelable support substrate at 23 ° C. 25 mm) was the following value. In addition, the inside of a parenthesis is the peeling force after a 150 degreeC x 3 minute heating.
PET: 2.8 (10.0)
Release PET (1): 0.21 (0.29)
Release PET (2): 0.69 (3.69)
Release PET (3): 0.27 (1.06)
Silicon coated glass (reference): 0, 40 (0.82)

  In Table 1, the heat shrinkage rate (%) means that the manufacturing example 1 is heated on a talc bath for 10 minutes at 150 ° C. and the manufacturing example 2 is 100 ° C. for 10 minutes. The rate of change was measured and calculated.

  Further, “after annealing” in the tape peeling force in Table 1 is the peeling force after the annealing treatment under each condition. The column for peeling evaluation in Table 1 also evaluates the peelability after the annealing treatment under each condition, and ◯: It can be peeled continuously without being caught by adhesion. Peeling marks cannot be confirmed, Δ (semi-adhesion): Separation can be intermittently caused by adhesion. It was evaluated that peeling traces were confirmed under the influence of intermittent peeling, x adhesion: the sealing material was deformed (stretched), or the support substrate was cut and could not be peeled.

<Test Example 2>
About the sealing material sheet which processed the unprocessed sealing material sheet of the said manufacture example 1 on annealing conditions 3 (150 degreeC, 3 minutes), the film thickness change before and behind annealing treatment was measured. The result is shown in FIG. As is apparent from FIG. 1, it can be seen that the change in film thickness is within a maximum of 15 μm with respect to the average film thickness of about 450 m, and a stable film thickness can be obtained when the ratio is 5% or less.

<Test Example 3>
About the sealing material sheet (film thickness 600 micrometers) of the said manufacture example 1, when annealing conditions 3 (150 degreeC, 3 minutes) were performed without a peeling support base material, the film thickness change before and behind annealing treatment was measured. The result is shown in FIG. As is apparent from FIG. 2, when there is no peelable support substrate as in Patent Document 1, the average was stable at 600 μm before annealing on the left vertical axis scale in FIG. Later, it can be understood that the film shrinks significantly to increase the film thickness, and that the film thickness variation is very large.

Claims (7)

A sheeting step for obtaining an untreated sealing material sheet that has not been annealed by melt molding the sealing material composition;
A laminating step in which the untreated sealing material sheet and the releasable support base material are pressure-bonded and bonded to obtain a laminate;
An annealing treatment step after the laminating step;
A method for producing a sealing material sheet for a solar cell module, comprising: a peeling step of peeling the peelable support substrate from the laminate after the annealing treatment step.   2. The peelable support substrate has a peeling force between the polyester substrate and the acrylic adhesive tape of 1.5 N / 25 mm or less under measurement conditions of 180 ° C. peeling and a peeling speed of 50 mm / min. The manufacturing method of the sealing material sheet | seat.   The said peelable support base material is a manufacturing method of the sealing material sheet | seat of Claim 1 or 2 provided with a silicone resin layer or a fluororesin layer on the surface of the said crimping | compression-bonding side at least.   2. The sealing material composition is an ethylene-vinyl acetate copolymer resin containing a crosslinking agent, and the MFR at 190 ° C. of the sealing material composition is 10 g / 10 min or more and 40 g / 10 min or less. The manufacturing method of the sealing material sheet in any one of 3 to 3.   The sealing material composition is a polyethylene-based resin containing a crosslinking agent, and the MFR at 190 ° C of the sealing material composition is 0.1 g / 10 min or more and 1.0 g / 10 min or less. 3. The manufacturing method of the sealing material sheet in any one of 3. The temperature in the annealing step is
The method for producing a sealing material sheet according to claim 5, wherein the melting point of the polyethylene-based resin is in a range from + 90 ° C. to melting point + 150 ° C. 6. A sealing material sheet for a solar cell module that is annealed after melt molding the sealing material composition,
The sealing material composition is a polyethylene resin containing a crosslinking agent,
The MFR at 190 ° C. of the sealing material composition is 0.1 g / 10 min or more and 1.0 g / 10 min or less,
The film thickness change in the TD direction of the encapsulant sheet is within 5% of the average thickness,
Shrinkage of test piece side length in MD direction before and after heating after placing test piece of sealing material film of 100 mm × 100 mm in the sealing material sheet on talc plate heated to 150 ° C. and allowing to stand for 10 minutes. The sealing material sheet characterized by the heat shrinkage rate which is a ratio being 30% or less.

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