JP2013026562A - Solar battery sealing material and solar battery module using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a solar battery sealing material having excellent resistance to heat and humidity, thermal shock cycle resistance and corrosion resistance in a contact interface between the solar battery sealing material and a solar battery cell surface that is an inorganic material; and a solar battery module using the solar battery sealing material.SOLUTION: A solar battery sealing material is used in a solar battery module. The solar battery sealing material is a polyolefin-based resin composition which is composed mainly of polyolefin-based resin, and further contains tackifying resin. A solubility parameter difference (SP value difference) between the polyolefin-based resin and the tackifying resin is 0.8 or more. The polyolefin-based resin is a propylene-ethylene copolymer whose ethylene content is 5-25 wt%.

Description

  TECHNICAL FIELD The present invention relates to a solar cell sealing material that is excellent in heat and humidity resistance, cold heat cycle resistance, and corrosion resistance, and mainly includes a polyolefin resin, and a solar cell module using the same.

  In recent years, solar cells that directly convert sunlight into electric energy have been widely used from the viewpoints of effective use of resources and prevention of environmental pollution. In order to promote the further spread of solar cells, performance, long-term reliability, etc. required for automobile members and building members are important.

  Generally, a solar cell module protects a solar cell element containing rare metal such as silicon (crystal, polycrystal, amorphous), gallium-arsenic, copper-indium-selenium, etc. with a light-receiving surface side transparent protective member and a back surface side protective member. The solar cell element and the protective member are fixed with a sealing material and modularized. The configuration of the solar cell module is slightly different depending on the type of the solar cell element described above, but the properties required for the solar cell element sealing material have good adhesion to the solar cell element and the protective member constituting the solar cell module. It is to be. In particular, since the solar cell module is installed outdoors and exposed to an increase in temperature and wind and rain, if the adherence between the adherend and the sealing material is poor, moisture may enter and the solar cell element may be deteriorated.

  Currently, ethylene / vinyl acetate copolymer (EVA) is used as a sealing material for a solar cell element in a solar cell module from the viewpoints of flexibility, transparency, and the like. However, because of its lack of heat resistance and adhesiveness, it is necessary to use organic peroxides and silane coupling agents together, to improve heat resistance by crosslinking, and to improve adhesiveness with silane coupling agents. (Patent Document 1). In this case, it is necessary to produce an ethylene / vinyl acetate copolymer sheet containing these additives and to seal the solar cell element using the obtained sheet. In the production stage of this sheet, it is necessary to form at a low temperature so that the organic peroxide is not decomposed, so the extrusion speed cannot be increased, and in the sealing stage of the solar cell element, in the laminator It takes two steps, consisting of a process of temporary bonding for several minutes to ten and several minutes and a process of main bonding for several tens of minutes to several hours at a high temperature at which the organic peroxide decomposes in the oven. It was necessary to go through a crosslinking and adhesion process. Therefore, it takes time and labor to manufacture the solar cell module, which is one of the factors that increase the manufacturing cost.

  Polyolefin resins, such as polypropylene resins, are excellent in moldability, flexibility, heat resistance, recyclability, chemical resistance, electrical insulation, etc., and are inexpensive, so films, fibers, In addition, it is widely used in a wide range of molded products of various shapes. On the other hand, a polypropylene-based material is a so-called non-polar and extremely inert polymer substance that does not have a polar group in the molecule, and its solubility in solvents is extremely low. is there. In order to remedy this drawback, a copolymerization of a polymerizable monomer having a polar functional group with ethylene has been studied (Patent Document 2). For example, when a monomer having an epoxy group is copolymerized with ethylene, It is necessary to use an amino group-containing coupling agent as an essential component, and such a copolymer has problems such as industrial difficulty in production and high cost. As a method for producing a modified resin by graft polymerization of a polymerizable monomer having a polar functional group to an olefin resin, the following method has been proposed.

  (I) A method in which a polyolefin resin particle dispersed in water is impregnated with a vinyl monomer and heated in the presence of a peroxide to produce a modified polyolefin (Patent Document 3).

  (Ii) A method for producing a modified polyolefin by melt-kneading a polyolefin resin, maleic anhydride and an organic peroxide (Patent Document 4).

  In the method (i), various vinyl monomers can be grafted onto the polyolefin resin. However, a monomer having a highly polar functional group such as an epoxy group is difficult to impregnate a polyolefin resin having a low polarity, so that the amount capable of copolymerization is limited. In addition, since a dissolution inhibitor of the monomer in water is required, the dissolution inhibitor remains in the modified polyolefin composition after the reaction, and there is a problem in that the paintability, adhesion and tackiness are hindered.

  Moreover, the method of adding tackifying resin which does not contain a polar group to a polypropylene resin is known (patent document 5). However, this technique is concerned about deterioration of heat resistance, and secondary processing is required to prevent it, which increases the manufacturing cost. Moreover, it is a heat-resistant and moisture-resistant film application for packaging and is not evaluated as a solar cell sealing material, and its performance is unknown. Moreover, the tackifying resin which does not have a polar group as mentioned above is added, and there exists a subject that adhesive force and adhesive force are low.

JP 2005-113077 A JP 2001-144313 A Japanese Patent Laid-Open No. 6-122738 Japanese Patent Laid-Open No. 9-278956 JP-A-7-157573

  The present invention uses a polyolefin resin to provide solar cells with excellent adhesion to solar cell elements and excellent long-term stability of solar cell quality (heat and humidity resistance, cold and heat cycle resistance, and corrosion resistance). It aims at providing the sealing material for batteries, and a solar cell module.

  As a result of intensive studies in view of the above-described present situation, the present inventors have encapsulated a specific polyolefin resin as a member (encapsulant) of a solar cell module containing a tackifier resin having an SP value difference of 0.8 or more. As a result of conducting a durability test using the material, it was found that long-term stability was exhibited, and the present invention was completed.

  That is, the present invention is a solar cell sealing material used in a solar cell module, which is a polyolefin resin composition containing a specific polyolefin resin as a main component and further containing a specific tackifying resin. It is related with the solar cell sealing material characterized by these. Specifically, it is a solar cell sealing material used in a solar cell module, which is a polyolefin resin composition containing a polyolefin resin as a main component and further containing a tackifying resin, and the polyolefin resin And the tackifier resin has a solubility parameter difference (SP value difference) of 0.8 or more, and the polyolefin resin is a propylene-ethylene copolymer having an ethylene content of 5 to 25 wt%. It is related with the solar cell sealing material characterized by these.

  As a composition having excellent adhesion, an olefin resin composition is known in which an olefin resin contains a tackifying resin having good compatibility (almost no difference in SP value). However, even if a tackifying resin having almost no difference in SP value is introduced to the olefin resin, it penetrates into the olefin resin, and when it is made into a sheet, an improvement in surface adhesion cannot be expected. Sometimes it peels off, and there is a risk that moisture will permeate there and deteriorate the solar cell element.

  In order to improve durability, studies have been made mainly to improve the adhesion between the adherend and the sealing material, but when using a tackifier resin having a large SP value difference (poor compatibility) with an olefin resin. Since there is a concern about the deterioration of the adhesion, the durability improvement effect has not been studied so far.

  In such a solar cell encapsulating material of the present invention, as a preferred embodiment, the solubility parameter difference (SP value difference) between the polyolefin-based resin and the tackifier resin is 0.8 or more, more preferably 1. 0 or more. From the viewpoint of appropriately dispersing the tackifier resin in the polyolefin-based resin, the SP value difference is preferably 1.4 or less, and more preferably 1.1 or less.

  As a preferred embodiment, the solar cell encapsulating material, the polyolefin resin composition is 0.1 to 50 parts by weight of the tackifying resin with respect to 100 parts by weight of the polyolefin resin, more preferably The present invention relates to a solar cell sealing material containing 1.0 to 20 parts by weight.

  In a preferred embodiment, the resin-providing resin is a terpene resin, more preferably a terpene phenol resin.

  As a preferable embodiment, the solar cell encapsulating material is a sheet or a film-shaped molded body, and more preferably, the thickness is 50 to 3000 μm.

  Furthermore, this invention relates to the solar cell module which uses the solar cell sealing material as described above.

  The solar cell sealing material excellent in durability of the present invention is suitably used as a material for improving long-term quality stability of solar cell module performance.

Solar cell module of the present invention Solar cell module of the present invention Heat and humidity resistance test results (relation between SP value difference and Pmax retention) Thermal cycle resistance test results (Relationship between SP value difference and Pmax retention rate)

  Details of the present invention will be described below.

  The solar cell sealing material of the present invention contains a polyolefin-based resin and a tackifying resin.

  The tackifier resin used in the present invention is preferably a terpene resin, and more preferably a terpene phenol resin from the viewpoint of the solubility parameter (SP value).

Among the terpene phenol resins, the softening point is in the range of 20 ° C. to 200 ° C. and the number average molecular weight is in the range of Mn = 200 to 2000 because of the difference in SP difference from the olefin resin and the improvement in adhesiveness. It is particularly preferred.
The amount of the tackifier resin used in the present invention is not particularly limited when blended, but it is preferably 0.1 to 50 parts by weight, preferably 0.3 to 30 parts by weight based on 100 parts by weight of the polyolefin resin. Part is more preferable, 0.5 to 20 parts by weight is further preferable, and 1.0 to 10 parts by weight is particularly preferable.

  Examples of the polyolefin resin used in the present invention include low density polyethylene, high density polyethylene, polypropylene homopolymer, linear low density polyethylene, poly-1-butene, polyisobutylene, propylene and ethylene and / or 1-butene. Random copolymer or block copolymer in any ratio, and ethylene-propylene-diene terpolymer having a diene component of 50% by weight or less in any ratio of ethylene and propylene, polymethylpentene, cyclopentadiene A cyclic polyolefin such as a copolymer of ethylene and / or propylene, ethylene or propylene and 50% by weight or less of a vinyl compound such as vinyl acetate, alkyl methacrylate, alkyl acrylate, aromatic vinyl, etc. Random copolymer, polyolefin-based thermoplastic elastomer block copolymer, olefin-based thermoplastic elastomer (simple mixture of polypropylene and ethylene / propylene copolymer or ethylene-propylene-diene terpolymer, partially crosslinked product thereof, Or a completely cross-linked product thereof), and the like can be used alone or in admixture of two or more.

  Among these, polyethylene, polypropylene, poly-1-butene, and a random copolymer or block copolymer of propylene and ethylene and / or 1-butene are preferable. In particular, it is preferably at least one selected from the group consisting of polyethylene, polypropylene, and propylene-ethylene copolymers. As a propylene-ethylene copolymer, it is especially preferable that ethylene content is 5-25 wt%. The polyethylene is particularly preferably low density polyethylene. If the polypropylene content is too high, the temperature range suitable for adhesion tends to be high, and if the ethylene content is too high, flexibility tends to decrease and it is difficult to protect the solar cell element.

  If necessary, another resin or rubber may be added to the raw material polyolefin resin as long as the effects of the present invention are not impaired.

  Examples of the other resin or rubber include polyethylene; poly α-olefins such as polypropylene, polybutene-1, polyisobutene, polypentene-1, and polymethylpentene-1; ethylene / propylene copolymer having a propylene content of less than 75% by weight. Copolymer, ethylene / butene-1 copolymer, ethylene or α-olefin / α-olefin copolymer such as propylene / butene-1 copolymer having a propylene content of less than 75% by weight; propylene content of 75% by weight Less than ethylene / propylene / 5-ethylidene-2-norbornene copolymer or ethylene- or α-olefin / α-olefin / diene monomer copolymer; polybutadiene copolymer such as polybutadiene and polyisoprene; styrene / Vinyl monomer such as butadiene random copolymer / Diene monomer random copolymer; vinyl monomer / diene monomer / vinyl monomer block copolymer such as styrene / butadiene / styrene block copolymer; hydrogenation (styrene / butadiene random) Hydrogenation (vinyl monomer / diene monomer random copolymer) such as copolymer); Hydrogenation (vinyl monomer / diene system) such as hydrogenation (styrene / butadiene / styrene block copolymer) Monomer / vinyl monomer block copolymer); vinyl monomer / diene monomer / vinyl monomer such as acrylonitrile / butadiene / styrene graft copolymer, methyl methacrylate / butadiene / styrene graft copolymer Polymer graft copolymer; polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyvinyl acetate, polyethyl acrylate, poly Vinyl polymers such as butyl acrylate, polymethyl methacrylate, polystyrene; vinyl chloride / acrylonitrile copolymer, vinyl chloride / vinyl acetate copolymer, acrylonitrile / styrene copolymer, methyl methacrylate / styrene copolymer, etc. Examples thereof include vinyl copolymers.

  The amount of other resin or rubber added to the polyolefin resin varies depending on the type of the resin or the type of the rubber, and as long as it is within the range not impairing the effects of the present invention as described above. % Or less is preferable.

  Furthermore, stabilizers such as antioxidants, metal deactivators, phosphorus processing stabilizers, UV absorbers, UV stabilizers, fluorescent brighteners, metal soaps, and antacid adsorbents are optionally added to polyolefin resins. Or additives such as cross-linking agents, chain transfer agents, nucleating agents, lubricants, plasticizers, fillers, reinforcing materials, pigments, dyes, flame retardants, antistatic agents, etc. are added within a range that does not impair the effects of the present invention. May be.

  Further, these polyolefin resins (which may contain various additive materials) may be in the form of particles or pellets, and the size and shape are not particularly limited.

  In addition, when the above additive material (other resin, rubber, stabilizer and / or additive) is used, even when the additive material is previously added to the polyolefin resin, the polyolefin resin is melted. It may be added to.

  There are no particular restrictions on the order of addition and method during melt-kneading of the polyolefin resin and the tackifier resin. In addition, the order and method of mixing and melt-kneading of materials added as necessary are not particularly limited.

  The heating temperature at the time of melt kneading is preferably 130 to 300 ° C. from the viewpoint that the polyolefin-based resin is sufficiently melted and is not thermally decomposed. The melt kneading time is usually 30 seconds to 60 minutes.

  Further, as the melt kneading apparatus, an extruder, a Banbury mixer, a mill, a kneader, a heating roll, or the like can be used. From the viewpoint of productivity, a method using a single-screw or twin-screw extruder is preferred. Moreover, in order to mix each material sufficiently uniformly, the melt kneading may be repeated a plurality of times.

  Examples of the polyolefin resin to be blended with the epoxy-modified polyolefin resin composition used in the present invention include polypropylene homopolymer, high density polyethylene, low density polyethylene, linear low density polyethylene, poly-1-butene, poly Isobutylene, random copolymer or block copolymer in any ratio of propylene and ethylene and / or 1-butene, ethylene-propylene-diene terpolymer having a diene component of 50% by weight or less in any ratio of ethylene and propylene A cyclic polyolefin such as a copolymer of an original copolymer, polymethylpentene, a copolymer of cyclopentadiene and ethylene and / or propylene, ethylene or propylene and 50% by weight or less of, for example, vinyl acetate, alkyl methacrylate, acrylic acid Random copolymers with vinyl compounds such as kill esters and aromatic vinyl, polyolefin-based thermoplastic elastomer block copolymers, olefin-based thermoplastic elastomers (polypropylene and ethylene / propylene copolymer or ethylene-propylene-diene ternary) A simple mixture of copolymers, a partially cross-linked product thereof, or a completely cross-linked product thereof) and the like. These may be used alone or in admixture of two or more.

  The sealing material obtained by using the polyolefin resin of the present invention to which a tackifying resin is added can be supplied as a sheet or a film-like molded body, and the thickness of the molded body can be exemplified as 50 μm to 3 mm. In view of imparting insulation properties and the like, the thickness is preferably 100 μm to 1 mm.

  The method for producing a sheet-like molded product obtained by using the polyolefin resin of the present invention with a tackifying resin added is not particularly limited. For example, a polyolefin resin composition and other compounding agents are dried. After blending and melt-kneading, it can be processed into a sheet-like molded product using various extrusion molding machines, injection molding machines, calendar molding machines, inflation molding machines, roll molding machines, or hot press molding machines. is there.

The solar cell module of the present invention has a sealing sheet obtained by using the polyolefin resin of the present invention added with a tackifying resin between the light-receiving surface side transparent protective member and the back surface side protective member. It is obtained by sealing the solar cell. In the solar cell module, in order to sufficiently seal the solar cell, there are roughly two sealing methods, crystalline and amorphous. In the case of a crystalline solar cell, as shown in FIG. 1, the light receiving surface side transparent protective member 1, the light receiving surface side sealing material 3 </ b> A, the solar cell 4, the back surface side sealing material 3 </ b> B, and the back surface side protective member 2 are provided. In the case of being laminated and amorphous, as shown in FIG. 2, the light receiving surface side transparent protective member 1, the solar cell 4 (in contact with the light receiving surface side transparent protective member), the back surface side sealing material 3B, The back surface protection member 2 is laminated and integrally molded with a vacuum laminator. Integrated molding with a vacuum laminator is performed at a temperature of 135 to 180 ° C., further 140 to 180 ° C., particularly 155 to 180 ° C., a degassing time of 0.1 to 5 minutes, a press pressure of 0.1 to 1.5 kg / cm ² , What is necessary is just to heat-press in press time 5-15 minutes. At the time of this heating and pressurization, a sealing sheet obtained by using a polyolefin resin used for the light-receiving surface side sealing material 3A and / or the back surface side sealing material 3B to which a tackifying resin is added is used as the light-receiving surface. The solar cell 4 can be sealed by bringing the side transparent protective member 1, the back side transparent member 2, and the solar cell 4 into close contact with each other. By using the encapsulant of the present invention for a solar cell having such a configuration, the encapsulant is used for a long period of time. It is possible to suppress a decrease in power generation performance and to have excellent durability.

  The light-receiving surface side transparent protective member used in the present invention is used in the form of a film, a sheet, or a plate. Usually, a material having practical strength and transparency such as a silicate glass or a polycarbonate plate is used, and a glass substrate is particularly preferable. As for the thickness of a glass substrate, 0.1-10 mm is common, and 0.3-5 mm is preferable. The glass substrate may generally be chemically or thermally strengthened.

  The back surface protection member used in the present invention is used in the form of a film, a sheet, or a plate. A laminated body of glass, aluminum foil, or plastic film is preferably used for the back surface protection member. Examples of the resin used for the plastic film include polyvinyl fluoride, polyethylene terephthalate, polyethylene naphthalate, polyethylene, and tetrafluoroethylene. -An ethylene copolymer etc. are mentioned, However, It is not limited to these. The back surface protection member is a single layer or a laminate having heat resistance, moisture resistance, weather resistance, and insulation generally called a back sheet.

  In addition, the solar cell of this invention has the characteristics in the sealing material used for the light-receiving surface side and / or back surface side as above-mentioned. Therefore, members other than the sealing material such as the light-receiving surface side transparent protective member, the back surface side protective member, and the solar battery cell are not particularly limited, and may have the same configuration as a conventionally known solar battery. That's fine.

  Specific examples are shown below, but the present invention is not limited to the following examples. In the following examples and comparative examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

(SP value calculation method)
The calculation method of the SP value of the homopolymer is represented by the following formula 1 based on the 2nd Polymer Material Forum of the Society of Polymer Science, Abstracts of Lectures, P167 (1993).

  Here, ΔF is the molar attractive constant of the atomic group, and Δv is the molar volume.

  Although the formula described in the above summary is used, this is based on a generally known Small calculation method (PA Small: J. Appl. Chem. (3), 71 (1953)) close to the actually measured value. It is corrected so that

Examples of reactive monomers having a homopolymer SP value of 9.8 (cal / cm ³ ) ^1/2 or more include acrylonitrile, methacrylonitrile, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-methacrylic acid 2- Examples thereof include hydroxyethyl, 4-hydroxybutyl acrylate, acrylic acid, methacrylic acid and the like.

  In the examples of the present specification, the SP value difference was calculated by the following formula 2.

(Evaluation of heat and humidity resistance of solar cell modules)
Using the solar cell encapsulant sheet of the present invention, a solar cell hybrid substrate (a material in which power generation elements are formed by vapor deposition and processing of silicon or the like on glass) having a vertical size of 240 mm and a horizontal size of 998 mm and a back sheet (manufactured by Toyo Aluminum Co., Ltd.) : TOYAL SOLAR FA20 / AL30 / BPET50 / LE50), the sheet for solar cell encapsulant of the present invention having a width of 250 mm and a length of 1100 mm was sandwiched, and was integrally formed with a vacuum laminator (Spi-Laminator). The conditions for the integral molding were 170 ° C., degassing time of 3.5 minutes, press pressure of 1 kg / cm 2, and thermocompression bonding with a pressing time of 10 minutes to obtain a solar cell module. When EVA-based resin is used as the sealing material, the integral molding conditions are 170 ° C., degassing time 3.5 minutes, press pressure 1 kg / cm 2, press pressure 3.5 mm, and press-bonding at 150 ° C. The solar cell module was obtained by heating in an oven for 120 minutes to crosslink EVA.

  The produced solar cell module was irradiated with pseudo-sunlight at 25 ° C. and an irradiation intensity of 1000 mW / cm 2 by a solar simulator whose spectrum was adjusted to AM 1.5, and the open voltage [V] of the solar cell and the nominal maximum per cm 2 The output operating current [A] and the nominal maximum output operating voltage [V] were measured, and the initial value of the nominal maximum output [W] (JIS C8911 1998) was determined from these products.

Next, the solar cell module is left in an environment of a temperature of 85 ° C. and a humidity of 85% RH for 1000 hours, and a heat and humidity resistance test is performed. ] And the superiority or inferiority of the heat and humidity resistance was determined. The judgment of superiority or inferiority was made as follows.
○: The value obtained by dividing the nominal maximum output after the 1000 hour heat and humidity resistance test by the initial value (Pmax retention rate) is 95.0% or more. Retention rate) is less than 95.0%

(Evaluation of thermal cycle resistance of solar cell modules)
The solar cell module produced by the above method was irradiated with pseudo-sunlight of 25 ° C. and an irradiation intensity of 1000 mW / cm 2 by a solar simulator whose spectrum was adjusted to AM 1.5, and the open voltage [V] of the solar cell and per 1 cm 2. The nominal maximum output operating current [A] and the nominal maximum output operating voltage [V] were measured, and the initial value of the nominal maximum output [W] (JIS C8911 1998) was determined from these products.

Next, the manufactured solar cell module is left for 200 cycles in an environment where the temperature is −40 ° C. to + 85 ° C. (temperature increase / decrease rate of 100 ° C./hr) for one cycle, and a thermal cycle test is performed. For the battery module, the nominal maximum output [W] was determined in the same manner as described above, and the superiority or inferiority of the cold-heat cycle resistance was determined. The judgment of superiority or inferiority was made as follows.
(Circle): The value Pmax retention ratio obtained by dividing the nominal maximum output after the 200-cycle cooling cycle test by the initial value) is 95.0% or more x: Value obtained by dividing the nominal maximum output after the 200-cycle cooling cycle test by the initial value Pmax retention) is less than 95.0%

(Evaluation of corrosion resistance of solar cell modules)
The solar cell module produced by the above method was immersed in a bath at a temperature of 50 ° C. and left in an environment where a voltage of 130 V was applied for 200 days, and a corrosion test was performed. About the solar cell module after leaving, the deterioration of the solar cell was observed visually, and the superiority or inferiority of the corrosion resistance was judged. The judgment of superiority or inferiority was made as follows.
○: No corrosion (white mark generation) is observed on the solar cell after the test for 200 days or more.
X: Corrosion (white mark generation) is observed in the solar cell after the test in less than 200 days.

Example 1
A twin-screw extruder (TEX30: L) in which 100 parts by weight of polypropylene ethylene rubber (Ders Chemical VERSIFY340.05, MFR = 8) and 10 parts by weight of terpene phenol resin (Yasuhara Chemical Co., Ltd .: YS Polystar T130) are set at 200 ° C. / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain pellets (a). The obtained pellet (a) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and cooled to a 0.40 mm thick solar cell sealing sheet ( b) was obtained. Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively. In the heat and humidity resistance test, the Pmax retention rate of 95.0% or more was maintained up to 4000 hr.

(Example 2)
A twin-screw extruder (TEX30: L) in which 100 parts by weight of polypropylene ethylene rubber (Ders Chemical VERSIFY340.05, MFR = 8) and 10 parts by weight of terpene phenol resin (Yasuhara Chemical Co., Ltd .: YS Polystar U130) are set at 200 ° C. / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain pellets (c). The obtained pellet (c) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and cooled to a 0.40 mm thick solar cell sealing sheet ( d) was obtained. Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively.

(Example 3)
A twin-screw extruder (TEX30: L) in which 100 parts by weight of polypropylene ethylene rubber (Ders Chemical VERSIFY340.05, MFR = 8) and 10 parts by weight of terpene phenol resin (Yasuhara Chemical Co., Ltd .: YS Polystar S145) are set at 200 ° C. / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain pellets (e).

  The obtained pellet (e) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and cooled to a 0.40 mm thick solar cell sealing sheet ( f) was obtained. Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively.

Example 4
A twin-screw extruder (TEX30: L) in which 100 parts by weight of polypropylene ethylene rubber (Ders Chemical VERSIFY340.05, MFR = 8) and 10 parts by weight of terpene phenol resin (Yasuhara Chemical Co., Ltd .: YS Polystar N125) are set at 200 ° C. / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain pellets (g).

  The obtained pellet (g) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and cooled to a 0.40 mm thick sheet for solar cell sealing ( h). Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively.

(Example 5)
A twin-screw extruder (TEX30: L) in which 100 parts by weight of polypropylene ethylene rubber (Ders Chemical VERSIFY340.05, MFR = 8) and 10 parts by weight of terpene phenol resin (Yasuhara Chemical Co., Ltd .: Mighty Ace G150) are set at 200 ° C. / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain pellets (i).

  The obtained pellet (i) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and cooled to a 0.40 mm thick solar cell sealing sheet ( j) was obtained. Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively.

(Example 6)
A twin-screw extruder (TEX30: L) in which 100 parts by weight of polypropylene ethylene rubber (Ders Chemical VERSIFY340.05, MFR = 8) and 10 parts by weight of terpene phenol resin (Yasuhara Chemical Co., Ltd .: Mighty Ace K125) are set at 200 ° C. / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain pellets (k).

  The obtained pellet (k) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and cooled to a 0.40 mm thick solar cell sealing sheet ( l) was obtained. Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively.

(Example 7)
A twin-screw extruder (TEX30: L) in which 100 parts by weight of polypropylene ethylene rubber (Ders Chemical VERSIFY340.05, MFR = 8) and 5 parts by weight of terpene phenol resin (Yasuhara Chemical Co., Ltd .: YS Polystar T100) are set at 200 ° C. / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain pellets (m). The obtained pellet (m) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and cooled to a 0.40 mm thick solar cell sealing sheet ( n) was obtained. Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively. In the heat and humidity resistance test, the Pmax retention rate was maintained at 95.0% or more up to 4000 hr, and the reliability was higher than that of EVA.

(Comparative Example 1)
Polypropylene ethylene rubber (Dersity Chemical VERSIFY340.05, MFR = 8) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and 0.40 mm thick The solar cell sealing sheet was obtained. Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively.

(Comparative Example 2)
A twin-screw extruder (TEX30: L) in which 100 parts by weight of polypropylene ethylene rubber (Ders Chemical VERSIFY340.05, MFR = 8) and 10 parts by weight of hydrogenated terpene resin (Yasuhara Chemical Co., Ltd .: Clearon P105) are set at 200 ° C. / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain pellets (p).

  The obtained pellet (p) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and cooled to a 0.40 mm thick solar cell sealing sheet ( q) was obtained. Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively.

(Comparative Example 3)
A twin-screw extruder (TEX30: L) in which 100 parts by weight of polypropylene ethylene rubber (Ders Chemical VERSIFY340.05, MFR = 8) and 10 parts by weight of hydrogenated terpene resin (Yasuhara Chemical Co., Ltd .: Clearon M115) are set at 200 ° C. / D = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain pellets (r).

  The obtained pellet (r) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and cooled to a 0.40 mm thick sheet for solar cell sealing ( s) was obtained. Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively.

(Comparative Example 4)
A twin screw extruder (TEX30: L / D) in which 100 parts by weight of low density polyethylene (Sumitomo Chemical Co., Ltd .: Sumikasen) and 10 parts by weight of hydrogenated terpene resin (Yasuhara Chemical Co., Ltd .: Clearon P105) are set at 200 ° C. = 28, manufactured by Nippon Steel Works) and melt-kneaded to obtain pellets (t). The obtained pellet (t) was hot pressed for 3 minutes at 200 ° C. and 50 kgf / cm 2 using a 0.40 mm thick spacer, then cooled and cooled to a 0.40 mm thick solar cell sealing sheet ( u) was obtained. Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively. As a result, in the heat and humidity resistance test, the Pmax retention rate was less than 95.0% at 1000 hr. Moreover, since the sheet was hard, cell cracks occurred during lamination, and there were many cases where the appearance was poor.

(Comparative Example 5)
A solar cell module was manufactured using a commercially available EVA sheet for sealing a solar cell (manufactured by Sunvic Co., Ltd .: Ultra Pearl, 0.40 mm thickness). Table 1 shows the results of heat and humidity resistance evaluation, cold and heat cycle resistance evaluation, and corrosion resistance evaluation. 3 and 4 show the relationship between the SP value difference and the Pmax retention rate in the heat and humidity resistance test and the cooling and heat cycle test, respectively. As a result, in the heat and humidity resistance test, the Pmax retention rate of 95.0% or more was maintained at 1000 hr, but the Pmax retention rate was less than 95.0% at 3000 hr.

1. 1. Light-receiving surface side transparent protective member Back side transparent protective member 3A. Light-receiving surface side sealing material 3B. 3. Back side sealing material Solar cell

Claims (6)

  A solar cell sealing material used in a solar cell module, which is a polyolefin resin composition containing a polyolefin resin as a main component and further containing a tackifier resin, and the polyolefin resin and the tackifier resin The solubility parameter difference (SP value difference) is 0.8 or more, and the polyolefin resin is a propylene-ethylene copolymer having an ethylene content of 5 to 25 wt%. Battery sealing material.   The sun according to claim 1, wherein the polyolefin-based resin composition is obtained by adding and melt-kneading the tackifier resin in an amount of 0.1 to 50 parts by weight with respect to 100 parts by weight of the polyolefin-based resin. Battery sealing material.   The solar cell sealing material according to claim 1, wherein the tackifying resin is 1.0 to 20 parts by weight.   The solar cell sealing material according to claim 1, wherein the tackifying resin is a terpene phenol resin.   The solar cell sealing material according to any one of claims 1 to 4, wherein the shape is a sheet or a film-like molded body.   The solar cell module using the solar cell sealing material of any one of Claims 1-5.

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