JP2014194971A - Method for manufacturing sealant master batch for solar battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealant master batch for offering a sealant for a solar battery module which has excellent adhesion durability in addition to high adhesion with a transparent substrate such as a piece of glass in manufacturing a sealant for a solar battery module which includes a polyethylene-based resin as a base resin.SOLUTION: A method for manufacturing a sealant master batch comprises the steps of: mixing and kneading a base resin for the master batch which includes a straight chain low-density polyethylene, 1-10 pts.mass of a silane coupling agent to 100 pts.mass of the base resin for the master batch, and 0.01-0.1 pts.mass of an organic peroxide for the master batch to 100 pts.mass of the base resin for the master batch at a temperature of 160-260°C; and causing the graft-polymerization of the base resin for the master batch and the silane coupling agent so that the peak intensity ratio of a SiC peak vs. a CHpeak is from 0.25 to 0.85.

Description

  The present invention relates to a sealing material master batch and a sealing material for a solar cell module.

  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 substrate, a solar cell element, and a back surface protection sheet are laminated via a sealing material for a solar cell module.

  Each member constituting the solar cell module or the like is always exposed to a harsh environment such as strong ultraviolet rays, heat rays, wind and rain. For this reason, each member which comprises a solar cell module needs to be equipped with durability over a long period of time on these conditions.

  As a sealing material for a solar cell module, a material using EVA (ethylene-vinyl acetate copolymer), which is excellent in transparency, adhesion, and the like, as a base resin has been widely used. However, in recent years, development of a sealing material using a polyethylene resin having a transparency equivalent to EVA and excellent in hydrolysis resistance as compared with EVA as a base resin has been progressing.

  When a polyethylene resin is employed as the base resin, it is known that the adhesion with glass or the like can be improved by blending a silane coupling agent. And in order to improve adhesiveness further, the sealing material using the modified ethylene-type resin which graft-polymerized alkoxysilane is proposed (refer patent document 1).

  Since the sealing material of Patent Document 1 is premised on not performing the crosslinking treatment, it is essential to use a modified ethylene-based resin having a melting point of 80 ° C. or higher. This is also clear from the fact that extrusion molding is performed at a high temperature of 180 ° C. in the examples of the silane-modified ethylene-α-olefin copolymer in the examples.

  Thus, when the base resin is a polyethylene-based resin, conventionally, high-temperature extrusion molding has been required. Therefore, in a composition containing a cross-linking agent, crosslinking has progressed during molding and molding has failed. Further, since the melting point of the base resin or the like is high, the density is increased and the transparency is inferior.

  Therefore, although the base resin is a polyethylene resin, it can be extruded at a low temperature and can be post-crosslinked. As a result, it is excellent in transparency, adhesion, and durability. Sealing using a sealing material composition containing, as a sealing material, a low-density, low-melting silane-modified polyethylene resin obtained by graft polymerization of an ethylenically unsaturated silane compound on linear low-density polyethylene, and a crosslinking agent. A stopping material has been proposed (Patent Document 2).

Japanese Patent Laid-Open No. 2002-235048 JP 2012-234965 A

  However, even if a silane coupling agent and an organic peroxide are simply mixed according to the description in Patent Document 2, sufficient adhesion cannot always be obtained. For example, in order to perform the above graft polymerization, a method of heating a base resin to which a silane coupling agent and an organic peroxide are added is generally used. In the case where a large amount of ring agent is present, there is a problem that particularly the durability of adhesion to glass is lowered.

  The present invention has been made to solve the above-described problems, and its purpose is to provide high adhesion to a transparent substrate such as glass in the production of a sealing material for a solar cell module based on a polyethylene resin. In addition to the property, it is providing the sealing material for solar cell modules which has the outstanding adhesion durability.

In the process of manufacturing a sealing material for a solar cell module, the present inventors have described a sealing material master batch for adding a silane-modified polyethylene resin to a sealing material composition used for manufacturing a sealing material. Focusing on the peak intensity ratio between the SiC peak and the CH ₂ peak of the modified polyethylene resin, it was found that the above problems can be solved by limiting the value of the intensity ratio to a specific range, and the present invention has been completed. More specifically, the present invention provides the following.

(1) A method for producing a masterbatch for a solar cell module encapsulant containing a silane-modified polyethylene resin, the masterbatch base comprising a linear low density polyethylene having a density of 0.900 g / cm ³ or less 1 part by mass or more and 10 parts by mass or less of a silane coupling agent with respect to 100 parts by mass of the base resin for masterbatch, and 0.01 part by mass or more to 100 parts by mass with respect to 100 parts by mass of the base resin for masterbatch. Including a step of kneading an organic peroxide for masterbatch of 1 part by mass or less at a temperature of 160 ° C. or higher and 260 ° C. or lower to prepare the silane-modified polyethylene resin, and SiC peak of the silane-modified polyethylene resin the peak intensity ratio of CH ₂ peak, so that 0.25 to 0.85, the masterbatch-based resin Method for producing a master batch for a solar cell module encapsulant, characterized in that graft polymerization of the silane coupling agent.

  (2) The manufacturing method of the masterbatch for solar cell module sealing materials as described in (1) whose said organic peroxide for masterbatch is a dialkyl peroxide or peroxycarbonate.

  (3) The manufacturing method of the masterbatch for solar cell module sealing materials as described in (1) or (2) whose said silane coupling agent is a silane coupling agent which has a vinyl group.

(4) A sealing material master batch for a solar cell module manufactured by the manufacturing method according to any one of (1) to (3), an organic peroxide for a sealing material composition, and a density of 0.900 g Of a sealing material for a solar cell module that is melt-extruded at 160 ° C. or higher and 260 ° C. or lower of a sealing material composition containing a base resin for a sealing material composition comprising a polyethylene-based resin of / cm ³ or less Method.

  ADVANTAGE OF THE INVENTION According to this invention, the sealing material masterbatch for solar cell modules which can manufacture the sealing material for solar cell modules which is excellent also in adhesive durability in addition to high adhesiveness with transparent substrates, such as glass, is provided. be able to.

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

  Hereinafter, a sealing material composition for a solar cell module according to the present invention, a sealing material composition containing the same master batch, a sealing material for a solar cell module that can be manufactured using the same sealing material composition, And the solar cell module using the same sealing material is demonstrated in detail in order.

<Encapsulant master batch>
First, the encapsulant master batch for the solar cell module of the present invention (hereinafter also simply referred to as “encapsulant master batch”) will be described.

[Encapsulant master batch]
The encapsulant masterbatch is a so-called masterbatch used for mixing a silane-modified polyethylene resin having a required concentration with an encapsulant composition used for manufacturing a solar cell module. In general, it contains a silane-modified polyethylene resin at a high concentration and is pelletized for easy adjustment. The sealing material composition according to the present invention uses low-density polyethylene as a base resin for the sealing material composition, and contains the sealing material master batch of the present invention and an organic peroxide as a crosslinking agent. And the said sealing material composition is melt-extruded and becomes the sealing material for solar cell modules which concerns on this invention.

The encapsulant masterbatch is mainly composed of a silane-modified polyethylene resin. The silane-modified polyethylene resin uses a linear low density polyethylene (LLDPE) with a density of 0.900 g / cm ³ or less as a base resin for a master batch, and a silane coupling agent is added to the resin in the presence of an organic peroxide. And a graft copolymer obtained by graft polymerization using a base resin as a main chain and a silane coupling agent (ethylenically unsaturated silane compound) as a side chain. Since the silane-modified polyethylene resin, which is such a graft copolymer, has a high degree of freedom of silanol groups that contribute to adhesion, it can improve the adhesion of the sealing material to other members in the solar cell module. Can do.

The sealing material master batch of the present invention is further characterized in that the graft ratio of the ethylenically unsaturated silane compound is limited to a predetermined range. Specifically, the encapsulant masterbatch of the present invention is obtained by subjecting the graft polymerization to a limited extent so that the peak intensity ratio of the SiC peak and the CH ₂ peak of the silane-modified polyethylene resin is in a specific range. It is. Here, the peak intensity ratio between the SiC peak and the CH ₂ peak (SiC peak value / CH ₂ peak value) in the present specification is obtained by cutting the pelletized encapsulant master batch flatly, and JASCO FT / IR 610 Each peak intensity is measured by the ATR method, and the value of “SiC peak value / CH ₂ peak value” calculated from the measured value is used.

Specifically, in the encapsulant masterbatch of the present invention, the peak intensity ratio of the SiC peak and the CH ₂ peak of the silane-modified polyethylene resin according to the above definition is preferably 0.25 or more and 0.85 or less. If the peak intensity ratio of the silane-modified polyethylene resin is less than 0.25, the adhesion maintenance ratio to glass becomes insufficient, and if it exceeds 0.85, it tends to become hard and the unevenness followability deteriorates. The present invention mainly comprises a silane-modified polyethylene resin obtained by graft-polymerizing a base polyethylene resin and an ethylenically unsaturated silane compound so that the peak intensity ratio of SiC peak and CH ₂ peak is in the above range. By adjusting the encapsulant composition using this encapsulant master batch, the adhesion durability of the encapsulant can be remarkably improved.

As the base resin for the master batch, linear low density polyethylene (LLDPE) having a density of 0.900 g / cm ³ or less is used. LLDPE is synthesized using a metallocene catalyst that 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 a sealing material. As a result of the flexibility imparted to the sealing material, the adhesion between the sealing material and a transparent front substrate such as glass can be enhanced.

  Since LLDPE has a narrow crystallinity distribution and a uniform crystal size, there is no LLDPE having a large crystal size. In addition, 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 containing the sealing material masterbatch of this invention is arrange | positioned between a transparent front substrate and a solar cell element, power generation efficiency hardly falls.

  As the α-olefin of LLDPE, an α-olefin having no branch is preferably used, and among these, 1-hexene, 1-heptene or 1-octene which is an α-olefin having 6 to 8 carbon atoms is preferable. Is particularly preferably used. When the number of carbon atoms of the α-olefin is 6 or more and 8 or less, the sealing material can be given good flexibility and good strength. As a result, the adhesion between the sealing material and the transparent front substrate such as glass is further enhanced.

  The silane coupling agent to be graft polymerized with LLDPE which is the base resin for masterbatch is not particularly limited, but those having a vinyl group can be particularly preferably used from the viewpoint of improving the film forming property. Specifically, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyltripentyloxysilane, vinyltriphenoxysilane, vinyltribenzyloxysilane, vinyltri A silane coupling agent consisting of one or more selected from methylenedioxysilane, vinyltriethylenedioxysilane, vinylpropionyloxysilane, vinyltriacetoxysilane, and vinyltricarboxysilane can be preferably used.

[Manufacturing method of encapsulant master batch]
The encapsulant master batch can be manufactured according to the method described in Japanese Patent Application Laid-Open No. 2003-46105, for example. However, as described above, in the sealing material masterbatch, the peak intensity ratio of the SiC peak and CH ₂ peaks, the graft polymerization of limiting masterbatch for the base resin and the silane coupling agent so that the predetermined range There is a unique feature of the production method of the present invention in that it proceeds.

In order to produce an encapsulant masterbatch, the above masterbatch base resin, the above silane coupling agent, and, if necessary, one or more kinds of other unsaturated monomers are desired. using the reaction vessel, for example, a pressure 500~4000Kg / cm ^2-position, preferably, 1000~4000Kg / cm ^2-position, 160 ° C. exceeding 260 ℃ less, preferably, a temperature of 180 to 240 ° C.-position, or less In the presence of an organic peroxide for masterbatch, which is described in detail in the following, random copolymerization is performed simultaneously or stepwise, and further, a portion of the silane compound constituting the random copolymer produced by the copolymerization is changed. Denature or condense. Under the present circumstances, a silane coupling agent is added in the ratio of 1 to 10 mass parts with respect to 100 mass parts of base resins for masterbatches.

  As the organic peroxide for masterbatch used for promoting the copolymerization of the masterbatch base resin and the silane coupling agent, alkyl peroxyesters, peroxycarbonates, dialkyl peroxides and the like can be used. Among these, in particular, dialkyl peroxide or peroxycarbonate can be preferably used. These organic peroxides for masterbatch are added at a ratio of 0.01 parts by mass or more and 0.1 parts by mass or less with respect to 100 parts by mass of the masterbatch base resin.

Then, the random copolymerization is allowed to proceed in a limited manner so that the peak intensity ratio between the SiC peak and the CH ₂ peak in the encapsulant master batch is 0.25 or more and 0.85 or less. A silane-modified polyethylene resin for producing a sealing material master batch can be produced. In order to improve the handling property at the time of adjustment, this silane-modified polyethylene resin is subjected to processing such as pelletization as necessary, and if necessary, in a minute range that does not impair the effects of the present invention, Other additives can be added to obtain the encapsulant masterbatch of the present invention.

In the above-described method for producing a sealing material master batch, mainly by adding the amount of the silane coupling agent, the type and amount of the organic peroxide for the master batch, and the like within the above preferable range, the sealing material The peak intensity ratio of the SiC peak and the CH ₂ peak of the silane-modified polyethylene resin in the master batch can be adjusted to 0.25 or more and 0.85 or less. Further, even when the various production conditions are not all in the preferred range, the peak intensity ratio between the SiC peak and the CH ₂ peak can be adjusted by appropriately adjusting other production conditions such as the heating time during kneading. The manufacturing method used as the sealing material containing the silane-modified polyethylene resin in the above range is within the scope of the present invention.

<Encapsulant composition>
Next, the encapsulant composition according to the present invention prepared by including the encapsulant master batch of the present invention (hereinafter, also simply referred to as “encapsulant composition”) will be described.

The sealing material composition includes a polyethylene resin having a density of 0.900 g / cm ³ or less as a base resin for the sealing material composition, the sealing material master batch of the present invention, and a sealing material composition as a crosslinking agent. It contains organic peroxide for physical use.

The low density polyethylene resin used as the base resin for the sealing material composition preferably has a density of 0.900 g / cm ³ or less, a melting point of less than 80 ° C., is unmodified with silane, and is composed of an olefin monomer. . In addition, the base resin for a sealing material composition preferably has a melting point difference from the sealing material master batch within 20 ° C, more preferably within 10 ° C. Furthermore, the base resin for the sealing material composition is preferably the same resin as the base resin for the masterbatch.

  Here, the MFR of the base resin for the sealing material composition is preferably 20.0 g / 10 min or more and 40.0 g / 10 min or less, and 25.0 g / 10 min or more and 35 g / 10 min or less. Is more preferable. By setting the MFR of the base resin for the sealing material composition to a high value of 20.0 g / 10 min or more and 40.0 g / 10 min or less, flexibility is given to the sealing material, and the sealing material and glass or the like are transparent. Adhesion with the front substrate can be improved. If the MFR of the base resin for sealing material is less than 20.0 g / 10 min, the viscosity is too high, and a cross-linking reaction occurs during molding due to heat generated during molding, making molding impossible. On the other hand, if the MFR of the base resin for the sealing material exceeds 40.0, the change in the film thickness of the sealing material at the time of producing the module is too large. In addition, it becomes difficult to achieve sufficient heat resistance as a sealing material for a solar cell module that is exposed to a harsh environment for a long time.

  A well-known thing can be used as an organic peroxide for sealing material compositions, It does not specifically limit, For example, a dialkyl peroxide or a peroxy carbonate can be used preferably. Other usable organic peroxides include hydroperoxides such as diisopropylbenzene hydroperoxide and 2,5-dimethyl-2,5-di (hydroperoxy) hexane; di-t-butyl peroxide, t -Butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-peroxy) hexyne-3 Dialkyl peroxides such as bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dichlorobenzoyl peroxide Class: t-butyl peroxyacetate, t-butyl peroxyacetate Xyl-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 Examples of oxyesters include ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide.

  As content of the organic peroxide for sealing material compositions, it is content of 0.5 mass part or more and 2.0 mass parts or less with respect to a total of 100 mass parts of all the resin components of a sealing material composition. It is preferable that the range is 0.5 parts by mass or more and 1.5 parts by mass or less. By adding the organic peroxide for a sealing material composition in this range, sufficient durability can be imparted to the sealing material.

The sealing material composition may further contain other components. For example, other polyolefin resins, or crosslinking aids such as polyfunctional monomers having a carbon-carbon double bond and / or an epoxy group, various fillers, light stabilizers, ultraviolet absorbers, heat stabilizers, etc. And the like. Other polyolefin-based resins preferably have a density of 0.900 g / cm ³ or less, a melting point of less than 80 ° C., are unmodified with silane, and are composed of olefin monomers. Accordingly, other polyolefin resins include low density polyethylene (LDPE), ethylene-vinyl acetate copolymer (EVA), and the like in addition to LLDPE that satisfies the above conditions. These may be used as an additive resin, for example, and can be used to make other components into a masterbatch. In addition, by including the above-described additive component in an appropriate amount range, it is possible to impart a long-term stable mechanical strength, an effect of preventing yellowing, cracking, and the like to the encapsulant composition.

[Encapsulant]
The encapsulant for the solar cell module of the present invention is obtained by molding the above encapsulant composition comprising the encapsulant master batch of the present invention by a conventionally known method, and a sheet. Or in the form of a film. In addition, the sheet form in this invention means the film form, and there is no difference in both.

  The sealing material composition is formed into a sheet by a conventionally known extrusion molding at a molding temperature of 160 ° C. or higher and 260 ° C. or lower. Thereby, the sealing material which concerns on this invention is obtained by forming the said sealing material composition into a sheet. Limited weak cross-linking without increasing the gel fraction may proceed during the melt extrusion molding, or the film may be formed without being cross-linked and cross-linking may proceed in the subsequent modularization process. .

  Further, the sealing material may be a single layer sheet or a multilayer sheet. In the case of a multilayer sheet, in order to improve adhesion with a glass substrate or the like in a solar cell module, an adhesion reinforcing layer made of a sealing material composition containing a sealing material master batch on the interface side with the glass substrate or the like It only has to be arranged. For this reason, for example, the sealing material may have a two-layer structure and the adhesion reinforcing layer may be disposed only on one layer, or the adhesion reinforcing layer may be disposed on at least one outermost layer with a core layer interposed therebetween. May be.

<Solar cell module>
FIG. 1: is sectional drawing which shows an example of the laminated constitution about the solar cell module 1 which is preferable one Embodiment of the sealing material manufactured using the sealing material masterbatch of this invention. In the solar cell module 1, a transparent front substrate 2, a front sealing material 3, a solar cell element 4, a back sealing material 5, and a back surface protection sheet 6 are sequentially laminated from the light receiving surface side of incident light. The solar cell module 1 uses the sealing material manufactured using the sealing material masterbatch of this invention as the front surface sealing material 3 and / or the back surface sealing material 5.

  For example, the solar cell module 1 is formed by sequentially stacking the members including the transparent front substrate 2, the front sealing material 3, the solar cell element 4, the back sealing material 5, and the back surface protection sheet 6, and then vacuum suction or the like. Then, the above-described members can be manufactured by thermocompression molding as an integral molded body by a molding method such as a lamination method. At this time, the front sealing material 3 made of a single-layer sheet and the glass substrate are laminated, or the adhesion reinforcing layer of the front sealing material 3 made of a multilayer sheet is an example of the transparent front substrate 2. By laminating so as to face the glass substrate, the adhesion between the glass substrate and the sealing material can be improved.

  The solar cell module 1 thus obtained is characterized by excellent adhesion between a transparent substrate made of glass or the like and a sealing material. That is, since the solar cell module 1 has improved the adhesion strength between the transparent substrate made of glass or the like and the sealing material, the solar cell module 1 is exposed to a harsh environment such as strong ultraviolet rays, heat rays, and wind and rain. Even so, it has extremely high durability over a long period of time.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

<Manufacture of encapsulant master batch>
The materials described below were mixed in the composition (in terms of parts by mass) shown in Table 1, and the resin melted and kneaded at 190 to 210 ° C. was pelletized, and Examples 1 to 6 and Comparative Examples 1 to 5 were used. An encapsulant master batch was produced. For the above melting and kneading treatments, a twin-screw extruder (Nippon Steel Works TEX) is used for kneading and extrusion, and the number of rotations per minute at that time is shown in Table 1 as “screw rotation number”. As described. The screw rotation speed and the reaction time are inversely proportional.
Masterbatch base resin (described as “MB / PE” in Table 1)
: Metallocene linear low density polyethylene which is a copolymer of ethylene and 1-hexene and has a density of 0.880 g / cm ³ and an MFR of 3.5 g / 10 min.
Silane coupling agent 1 (described as “SC1” in Table 1)
: Vinyltrimethoxysilane. (Product name “KBM-1003” manufactured by Shin-Etsu Chemical Co., Ltd.)
Silane coupling agent 2 (described as “SC2” in Table 1)
: 3-acryloxypropyltrimethoxysilane. (Product name “KBM-5103” manufactured by Shin-Etsu Chemical Co., Ltd.)
Organic peroxide 1 for masterbatch (described as “MB / peroxide 1” in Table 1)
Dialkyl peroxide (manufactured by Arkema Yoshitomi, trade name “Lupelox 101”). 1 minute half-life temperature 181 ℃
Organic peroxide 2 for masterbatch (described as “MB / peroxide 2” in Table 1)
Peroxycarbonate (trade name “Lupelox TBEC”, manufactured by Arkema Yoshitomi Corporation). 1 minute half-life temperature 166 ° C
Organic peroxide 3 for masterbatch (described as “MB / peroxide 3” in Table 1)
Alkyl peroxyester (trade name “Lupelox 570”, manufactured by Arkema Yoshitomi Corporation). 1 minute half-life temperature 152 ° C

The peak intensity ratio (SiC peak value / CH ₂ peak value) of the SiC peak and the CH ₂ peak of the silane-modified polyethylene resin in the state of each of the encapsulant master batches of Examples and Comparative Examples manufactured as described above is “peak”. The intensity ratio is shown in Table 1. Note that the peak intensities of the SiC peak and the CH ₂ peak were measured by the ATR method of JASCO FT / IR 610 after cutting the pelletized resin to be measured in the same manner as in the above measurement method. Peak of SiC, ^{1090 cm} -1, the peak of the CH ₂ was the intensity ratio using the 1465cm ^-1.

<Manufacture of sealing material>
15 parts by mass of the encapsulant masterbatch of any of the above Examples 1 to 5, Comparative Examples 1 to 5, or Reference Example, 80 parts by mass of the base resin for encapsulant composition described below, and The encapsulant composition obtained by mixing 5 parts by mass of the organic peroxide for an encapsulant composition and the other additives described below is melted to a thickness of 400 μm by a conventional T-die method. Thus, it formed into a film at the film forming temperature of 220 degreeC, and obtained each sealing material of an Example, a comparative example, and a reference example. In addition, the sealing material manufactured using the sealing material masterbatch of Example 1 was used as the sealing material of Example 1, and the sealing material manufactured using the masterbatch of Comparative Example 1 was sealed in Comparative Example 1. A material was used. And similarly, the sealing materials of Examples 2 to 6, the sealing materials of Comparative Examples 2 to 5, and the sealing materials of Reference Examples are used for the sealing materials using the respective sealing material master batches. It was.
Base resin for encapsulant composition: a metallocene linear low density polyethylene which is a copolymer of ethylene and 1-hexene and has a density of 0.880 g / cm ³ and an MFR of 3.5 g / 10 min.
Organic peroxide for sealing material composition: Same as organic peroxide 1 for masterbatch. (Dialkyl peroxide (manufactured by Arkema Yoshitomi Corporation, trade name “Lupelox 101”). 1 minute half-life temperature 181 ° C.)
In addition to the above materials, the following materials were used in the compositions as described below as materials common to the sealing materials of all Examples, Comparative Examples, and Reference Examples.
UV absorber: Benzophenone ultraviolet absorber. Addition of 0.25 parts by mass to each example, comparative example, and reference example.
Weather resistance stabilizer: A hindered amine light resistance stabilizer. 0.2 parts by mass added to each example, comparative example, and reference example.
Antioxidant: A hindered phenolic antioxidant. 0.05 parts by mass added to each Example and Comparative Example.

<Evaluation Example 1>
Each of the sealing materials of Examples and Comparative Examples is closely attached to a glass substrate (white plate float semi-tempered glass JPT3.2 75 mm × 50 mm × 3.2 mm), and is subjected to vacuum heating laminator treatment at 150 ° C. for 7 minutes. It was created. In the above sample for evaluation, the sealing material adhered on the glass substrate was cut to a width of 15 mm, and a vertical peel test (50 mm / min) was performed using a peel tester (Tensilon Universal Tester RTF-1150-H). The initial glass adhesion strength was measured. The results are shown as “Initial adhesion” in Table 2.
Thereafter, the maintenance rate of the glass adhesion strength after the following dump heat (DH) test with respect to the initial glass adhesion strength was further measured for the sample for evaluation. D. H. The test was based on JIS C8917, and the durability test of the sample for evaluation was performed for 1000 hours under the conditions of 85 ° C. in the test tank and 85% humidity. For the evaluation materials after the test, the same test as above was performed to measure the durability adhesion. The ratio of the durable adhesion value to the initial adhesion strength is shown in Table 2 as “durable adhesion”. And it evaluated that durable adhesiveness was preferable because the value of this durable adhesion is 20 N / 15mm or more.

<Evaluation Example 2>
As shown in Table 2, although the sealing material of the reference example was usable to a sealing material for a solar cell module, some gel was generated during film formation. On the other hand, in the sealing materials of Examples 1 to 5, no such gel was generated during film formation. This result shows that it is preferable to use what has a vinyl group for the silane coupling agent used for manufacture of the sealing material of this invention.

  From the results shown in Tables 1 and 2, the encapsulant master in which the graft ratio of the ethylenically unsaturated silane compound in the encapsulant masterbatch used by adding to the encapsulant composition is limited to a predetermined range unique to the present invention. The encapsulant for solar cell modules manufactured using a batch has high initial glass adhesion and superior glass compared to other encapsulants using a master batch whose graft ratio is outside the predetermined range. It can be seen that it has an adhesion maintenance rate.

DESCRIPTION OF SYMBOLS 1 Solar cell module 2 Transparent front substrate 3 Front sealing material 4 Solar cell element 5 Back surface sealing material 6 Back surface protection sheet

Claims (4)

A method for producing a sealing material master batch for a solar cell module containing a silane-modified polyethylene resin,
A base resin for a masterbatch comprising linear low density polyethylene having a density of 0.900 g / cm ³ or less;
1 part by mass or more and 10 parts by mass or less of a silane coupling agent with respect to 100 parts by mass of the base resin for masterbatch,
0.01 parts by mass or more and 0.1 parts by mass or less of organic peroxide for masterbatch with respect to 100 parts by mass of the base resin for masterbatch is kneaded at a temperature of 160 ° C. or more and 260 ° C. or less, and the silane Including a step of creating a modified polyethylene resin,
Graft-polymerizing the masterbatch base resin and the silane coupling agent so that the peak intensity ratio of the SiC peak and the CH ₂ peak of the silane-modified polyethylene resin is 0.25 or more and 0.85 or less. The manufacturing method of the sealing material masterbatch for solar cell modules characterized by these.   The method for producing a sealing material master batch for a solar cell module according to claim 1, wherein the organic peroxide for master batch is dialkyl peroxide or peroxycarbonate.   The method for producing a sealing material master batch for a solar cell module according to claim 1 or 2, wherein the silane coupling agent is a silane coupling agent having a vinyl group. A sealing material master batch for a solar cell module manufactured by the manufacturing method according to claim 1, an organic peroxide for a sealing material composition, and a density of 0.900 g / cm ³ or less. The manufacturing method of the sealing material for solar cell modules which melt-extrudes the sealing material composition containing the base resin for sealing material compositions which consists of polyethylene-type resin at 160 degreeC or more and 260 degrees C or less.

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