JP2011084688A - Hot-melt composition and solar battery panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot-melt composition which hardly flow even if pressure is applied thereto at a high temperature and has a practical melt viscosity. <P>SOLUTION: The hot-melt composition includes: a styrenic block copolymer; butyl rubber; a polypropylene resin which accounts for 1-20 wt.% of the total amount of the hot-melt composition and has a softening point of 150°C or higher; and an inorganic filler which accounts for 1-50 wt.% of the total amount of the hot-melt composition. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an improvement in heat resistant flow property of a hot melt composition and a solar cell panel using the same.

  A solar cell is a power generation device that converts light energy into electric power, can generate power continuously without the need for fuel, etc., has no moving parts, has excellent maintainability, does not emit greenhouse gases such as carbon dioxide, It can be installed on a wall and does not take up space. It can be installed in other places such as outer space, mountainous areas, remote islands where power generation and feeding methods are difficult, and as a clean power generator in offices and homes. It has come to be.

  A solar battery panel is manufactured by protecting a power generating element called a cell with respect to glass using a sealing resin such as EVA having excellent buffering properties, and further laminating with a film. Sealing resin such as EVA Since the moisture barrier property is not sufficient, a panel is formed by providing a moisture barrier layer on the outer layer of the sealing resin with a hot melt resin containing butyl rubber and the like and holding it with a metal frame.

  In recent years, in order to reduce the manufacturing cost of solar cell panels, a method for forming a panel without using a metal frame by replacing the film on the back side with glass has been studied, and both sides use glass. It is called double glass type. In the double glass type, not only a cell and a sealing resin but also a resin that becomes a moisture barrier layer is disposed between two glass plates.

  The process of integrating the solar cell panel into such a configuration is performed by vacuum pressing at a high temperature of about 150 ° C. On the other hand, in this temperature range, resin components such as butyl rubber are also softened and easily flow, so that the resin flows due to the press, and the moisture barrier property tends to be lowered or the appearance is liable to be deteriorated. In addition, hot melt resins using a resin having a high softening point have a problem that the melt viscosity becomes high and the workability is deteriorated or the adhesion to the substrate is lowered.

Patent Document 1 discloses a hot-melt type sealing material that is excellent in heat resistance and the like, but it does not take into account the fluidity against the press pressure at a high temperature of about 150 ° C.
Japanese Patent Laid-Open No. 10-102024

  An object of the present invention is to provide a hot melt composition that hardly flows even under pressure at high temperatures, has a practical melt viscosity, and is excellent in adhesion to a substrate.

  The present invention is a hot melt composition comprising a styrene block copolymer, butyl rubber, a polypropylene resin having a softening point of 150 ° C. or higher, and an inorganic filler.

  The hot melt composition of the present invention hardly flows even under pressure at high temperatures. Further, since it has a practical melt viscosity, it can be applied with good workability using a normal coating apparatus. Furthermore, various substrate adhesiveness to glass etc. is favorable. Therefore, the hot melt composition of the present invention exhibits excellent performance in various uses such as adhesives and sealants that require heat resistance. A particularly suitable application is a sealing material for forming a moisture barrier layer of a double glass solar cell panel.

  Hereinafter, each essential component of the hot melt composition used in the present invention will be described. The styrenic block copolymer is blended in the sealing material to ensure elasticity, cohesion and adhesion to the substrate, and the average molecular weight is 30000 to ensure elasticity and cohesion. 500,000 are compatible. Specifically, styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butadiene-styrene block copolymer (SEBS), α-methylstyrene- Butadiene-α-methylstyrene block copolymer, α-methylstyrene-isoprene-α-methylstyrene block copolymer, and hydrogenated modified products thereof such as styrene-ethylene- (ethylene-propylene) -styrene block copolymer Examples thereof include coalescence (SEEPS) and styrene-ethylene-propylene-styrene block copolymer (SEPS).

  Butyl rubber is compounded for the purpose of imparting sealing properties, weather resistance, water resistance, heat resistance, impact absorption, etc. to a hot melt composition for sealing, and has a Mooney viscosity of 20 to 90 and an unsaturation degree of 0 The thing of about 5-5.0 is preferable. The blending amounts of butyl rubber and styrenic block copolymer are preferably selected in the range of 20 to 35% by weight and 3 to 15% by weight, respectively, with respect to the entire hot melt composition.

  Polypropylene resins having a softening point of 150 ° C. or higher are added for the purpose of improving heat resistant flow properties and lowering melt viscosity, and may be of various modified types. Specific examples include Viscol 440P (trade name, manufactured by Sanyo Chemical Industries) having a softening point of 157 ° C. It is not preferable to use only a polypropylene resin having a softening point of less than 150 ° C instead of a polypropylene resin having a softening point of 150 ° C or higher. It is possible to use a polypropylene resin having a point of less than 150 ° C. in combination. The blending amount of the polypropylene resin having a softening point of 150 ° C. or higher is preferably 1 to 20% by weight with respect to the entire hot melt composition. When the content is 1% by weight or more, the heat resistant flow property is remarkably exhibited, and when the content is less than 20% by weight, problems such as a decrease in adhesion to the base material hardly occur.

  The inorganic filler is added for the purpose of improving the heat resistant flow property. Specific examples include calcium carbonate, talc, clay, silica, titanium oxide and the like. It is preferable that the compounding quantity of an inorganic filler shall be 1-50 weight% with respect to the whole hot-melt composition. When it is 1% by weight or more, the heat resistant flow property is remarkably exhibited, and when it is less than 50% by weight, there is little possibility that the melt viscosity becomes too high.

  In addition to the essential components, organic fine particles can be added to the hot melt composition. By adding organic fine particles, when the sealing layer made of the hot melt composition is subjected to a pressing pressure, it is possible to secure a film thickness corresponding to the particle diameter of the organic fine particles, so that the hot melt composition flows. Can be avoided.

  Organic fine particles include, for example, aromatic vinyl monomers such as styrene, α-methylstyrene and vinyltoluene, alkyl acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate, methyl methacrylate, ethyl methacrylate, methacryl Methacrylic acid alkyl esters such as butyl acid, vinyl ester monomers such as vinyl acetate and vinyl propionate, vinylcyan monomers such as (meth) acrylonitrile, vinyl halides such as vinyl chloride and vinylidene chloride It is obtained by suspension polymerization of the body.

The preferable particle diameter of the organic fine particles varies depending on the required film thickness of the seal layer, but is preferably about 200 to 1000 μm. Further, in order to withstand the pressing pressure at high temperature, it is preferable that the gel fraction should be 10% or more, more preferable gel fraction is 30% or more, and further preferable gel fraction is 60% or more. There is a particularly preferred gel fraction of 90% or more. The gel fraction means that 1 g of organic fine particles is put in 30 g of acetone, stirred for 1 hour in a glass beaker, centrifuged, and the supernatant is removed and dried under reduced pressure at 80 ° C. for 12 hours. Ag), which is calculated by the following equation.
Gel fraction (%) = (A / 1) × 100

  In addition to the above-described blending components, various additives such as tackifier resins, liquid resins, antioxidants, silane coupling agents, and pigments can be blended in the hot melt composition. Examples of tackifying resins include terpene resins, terpene phenol resins, rosin resins, hydrogenated rosin resins, petroleum resins, hydrogenated petroleum resins, and the like. Specific examples of the liquid resin include liquid polybutadiene and liquid polybutene.

  Antioxidants include copper-based antioxidants, copper salt-based antioxidants, copper halide-based antioxidants, phosphorus-based antioxidants, phenol-based antioxidants, hindered amine-based antioxidants, sulfur-based antioxidants Examples thereof include a metal deactivator comprising an inhibitor, a lactone-based antioxidant, an aromatic amine, and a chelating agent.

Examples of phenolic antioxidants include 2,6-di-t-butylphenol derivatives, 2-methyl-6-t-butylphenol derivatives, octadecyl-3- (3,5-dibutyl-4-bitoxyphenyl) propionate, 4 , 4-Butylidene-bis (6-t-butyl-m-cresol), pentaerythrityl tetrakis {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate}, 2- {1- (2-hydroxy-3,5-di-t-pentylphenyl) -ethyl} -4,6-di-t-pentylphenyl acrylate and the like.

  Phosphorus antioxidants include tris (2,4-di-t-butylphenyl) phosphate, cyclic neopentanetetrabis (2,4-di-t-butylphenyl phosphate, dostearyl pentane erythritol diphosphate , Sodium dihydrogen phosphate, and disodium monohydrogen phosphate.

  Examples of hindered amine antioxidants include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1 , 2,3,4-Tetrakis (2,2,6,6-tetramethyl-4-piperidyloxycarbonyl) butane, dimethyl-1- (2-hydroxylethyl-4-hydroxy-2,2,6, succinate) 6-tetramethylpiperidine polycondensate, 1- (3,5-di-t-butyl-4-hydroxyphenyl) -1,1-bis (2,2,6,6-tetramethyl-4-piperidyloxycarbonyl) ) Pentane, N, N-bis (3-aminopropyl) ethylenediamine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, bis (octylone-2,2,6, - tetramethyl-4-piperidyl) sebacate, and the like.

  The hot melt composition can be obtained by kneading the above-described blended components with a Banbury mixer, a heating kneader, a uniaxial to biaxial extruder, or the like. The melt viscosity of the hot melt composition is preferably 3000 Pa · s or less, more preferably 2000 Pa · s or less, at 200 ° C. When it exceeds 3000 Pa · s at 200 ° C., the coating property is deteriorated, so that it takes time for the coating operation, and the load is increased in a general-purpose coating device, so that the damage to the device is accelerated. Further, if the melting temperature is raised, the melt viscosity is lowered, but the hot melt composition is likely to deteriorate, which is not preferable.

  The hot melt composition of the present invention is excellent in adhesion to various substrates, hardly flows even under pressure at high temperatures, and has a practical melt viscosity, so it is useful as a hot melt type adhesive or sealing material. It is. Further, it is particularly suitable as a sealing material for forming a moisture barrier layer of a sealing resin for a solar cell panel.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not restrict | limited to these Examples.

Manufacture of hot melt composition Butyl065 (trade name, manufactured by Nippon Butyl Co., Ltd.), 140 parts by weight of butyl rubber, SEPTON 2063 (product name, manufactured by Kuraray Co., Ltd.), SEBS, 20 parts by weight, biscol, a polypropylene resin having a softening point of 157 ° C. 440P (manufactured by Sanyo Chemical Industries, trade name) 50 parts by weight, 20 parts by weight of biscol 660P (trade name, made by Sanyo Chemical Industries, trade name), a polypropylene resin having a softening point of 145 ° C., BF200 (Shiraishi Calcium Co., Ltd.), calcium carbonate Manufactured, trade name) 120 parts by weight, carbon black Dia Black MA100 (Mitsubishi Chemical Co., trade name) 3 parts, terpene resin YS Polystar U130 (Yasuhara Chemical Co., trade name) 40 parts by weight, antioxidant Irganox 1010 (trade name, manufactured by Ciba Geigy) 0.5 parts by weight, 70 parts by weight of HV-300 (trade name) manufactured by Nippon Petrochemical Co., Ltd., and 1 part by weight of APDS (product name of Chisso Corp.), a silane coupling agent, by sigma blade type A hot melt composition of Example 1 was obtained by heating and mixing with a kneader. Similarly, the hot melt compositions of Example 2 and Comparative Examples 1 to 3 were obtained with the formulations shown in Table 1. Each hot melt composition was evaluated by the following method.

Melt viscosity Melt viscosity (0.5 rpm) at 200 ° C. was measured using a digital viscometer manufactured by Brookfield (model: DVI-I +).

Shear test Each hot melt composition was molded into a square sheet of 20 mm x 20 mm (thickness 1 mm), sandwiched between two glass plates 60 mm long x 20 mm wide (thickness 2 mm), and fixed with a curing tape. The sample was left in an atmosphere at 150 ° C. for 10 minutes, lightly pressed immediately after removal, and further cured for 1 day. A shear test was carried out at a crosshead speed of 20 mm / min, and a case where cohesive failure was observed was evaluated as ◯ and a case where interfacial failure was evaluated as x.

Heat-resistant flow test Each hot melt composition was molded into a square sheet of 14 mm x 14 mm (thickness 2 mm), sandwiched between two glass plates (28 g), and the test specimen was marked by marking the square shape on the glass plate It was created. After the test body was allowed to stand in an atmosphere of 150 ° C. for 1 hour, the distance that the hot melt composition protruded from the pre-test shape (marked shape) and spread was measured for each side, and the total was evaluated.

  Each example was excellent in heat-resistant flow property, and there was no problem in adhesion and melt viscosity. On the other hand, none of the comparative examples had sufficient heat resistant flow properties.

Claims (4)

  A hot melt composition comprising a styrene block copolymer, butyl rubber, a polypropylene resin having a softening point of 150 ° C. or higher, and an inorganic filler.   The hot melt composition according to claim 1, wherein the content of the polypropylene resin is 1 to 20% by weight and the content of the inorganic filler is 1 to 50% by weight with respect to the entire hot melt composition. Melt composition.   The hot melt composition according to claim 1 or 2, further comprising organic fine particles.   A solar cell panel manufactured using the hot melt composition according to claim 1.