Nok Corporation

Unimatec Co., Ltd

Nok Kluber Co., Ltd.

Masashi Kudo

Masaya Otsuka

Osamu Kobayashi

Takeshi Sato

Hideyuki Tokumitsu

Satoru Saito

Takashi Amemiya

Jun Kanega

Satoshi Horie

Chiyota Ogata

Tatsuo Okamura

Arata Iida

A silicone rubber composition, which comprises 100 parts by weight of vinyl group-introduced methylphenylvinyl-based silicone rubber obtained by copolymerization of dimethylsiloxane copolymerization units as the main component with 3-30 mol. % of methylphenylsiloxane copolymerization units, and 0.2-8 parts by weight of an organic peroxide, where introduction of vinyl groups into the silicone rubber can be attained generally by copolymerization of 0.1-5 mol. % of methylvinylsiloxane. When silica is used as a filler, it is desirable to use a surfactant for silica, and water together. Owing to distinguished low-temperature characteristics and blister resistance, the present silicone rubber composition can be used a suitable seal material for a high-pressure hydrogen gas storage tank, for example, to storage under 70 MPa, and particularly as suitable vulcanization-molding materials for O rings, packings, gaskets, oil seals, valves, etc.

Silicone rubber composition

A silicone rubber composition, which comprises 100 parts by weight of a vinyl group-introduced methylfluoroalkylvinyl-based silicone rubber obtained by copolymerization of a dimethylsiloxane copolymerization unit as the main component with 5-50% by mole of a methylfluoroalkylsiloxane copolymerization unit, and 0.2-8 parts by weight of an organic peroxide. When silica is used as a filler, it is desirable to use a surfactant for silica, and water at the same time. The present silicone rubber composition can give distinguished low-temperature characteristics and blister resistance, and thus can be used for seal materials directed to high-pressure hydrogen gas storage tanks, for example, to storage under 70 MPa, and particularly as suitable vulcanization-molding materials for O-rings, packings, gaskets, oil seals, valves, etc. High-pressure gases for storage are not limited only to hydrogen gas, but also to oxygen gas, nitrogen gas, helium gas, etc. likewise.

A fluorine-containing elastomer having a copolymer composition, which comprises 50-85% by mole of (a) vinylidene fluoride, 0-25% by mole of (b) tetrafluoroethylene, 7-20% by mole of (c) perfluoro(methyl vinyl ether), 3-15% by mole of (d) CF&#x2550;CFO[CFCF(CF)O]nCFand 0.1-2% by mole of (e) RfX, where Rf is an unsaturated fluorohydrocarbon group having 2-8 carbon atoms and X is a bromine or iodine atom, can give curing products with distinguished low-temperature characteristics and solvent resistance without deteriorating the distinguished moldability and compression set characteristics proper to the fluorine-containing elastomer, and a fluorine-containing elastomer composition, which comprises 100 parts by weight of the present fluorine-containing elastomer, 0.1-10 parts by weight of an organic peroxide, 0.1-10 parts by weight of a polyfunctional unsaturated compound and not less than 2 parts by weight of an acid acceptor can give curing products with distinguished low-temperature characteristics and fuel oil resistance.

Fluorine-containing elastomer and its composition

A fluororubber sealant composition includes 100 parts by weight of a fluororubber, which is a copolymer having a cross-linking site derived from a bromine-containing and/or iodine-containing compound, capable of crosslinking with peroxide and having a component unit composition comprising 20 to 23% by mol of a perfluoromethyl vinylether component unit, 60 to 70% by mol of a vinylidene fluoride component unit, 10 to 20% by mol of a tetrafluoroethylene component unit, 0 to 10% by mol of hexafluoropropylene component unit (based on 100% of the total of the above component units), and a small amount of a bromide and/or iodide unsaturated fluorohydrocarbon component unit as a crosslinking site based on 100% by mol of the total of the above component units; and further comprising, based on 100 parts by weight of the fluororubber, 2 to 50 parts by weight of a bituminous fine powder; 0.5 to 6 parts by weight of an organoperoxide; and 1 to 10 parts by weight of a polyfunctional monomer. A sealant is prepared by vulcanizing the above composition. The composition has not only excellent ordinary physical properties but also excellent heat resistance, freeze resistance and fuel oil resistance so that it is suitably used as sealants for automobile fuel.

Fluororubber base sealant composition and fluororubber base sealant

A molding material for use with carbon dioxde, which comprises chlorinated polyethylene having a chlorine content of 25&#x2013;47% by weight or a blend of chlorinated polyethylene with vinyl chloride-based resin, can be used as a suitable material for sealing materials in carbon dioxide-contacting apparatuses using carbon dioxide as a refrigerant. Addition of a specific silane coupling agent to the molding material can effectively prevent vulcanization moldings from blister generation.

Molding material for use with carbon dioxide

A molding material for use with carbon dioxide, which comprises chlorinated polyethylene having a chlorine content of 25-47% by weight or a blend of chlorinated polyethylene with vinyl chloride-based resin, can be used as a suitable material for sealing materials in carbon dioxide-contacting apparatuses using carbon dioxide as a refrigerant. Addition of a specific silane coupling agent to the molding material can effectively prevent vulcanization moldings from blister generation.

Molding material for use with carbon dioxide refrigerant

A butyl rubber composition, which comprises 100 parts by weight of butyl rubber and 30 to 150 parts be weight of carbon black having a CTAB specific surface area of 30 to 100 m /g and preferably further contains 10 to 100 parts by weight of a flat filler having an average particle size of 1 to 40 &mgr;m and an aspect ratio of 5 or more and 0.05 to 5 parts by weight of a coupling agent of organometallic compound is provided. The butyl rubber composition can give vulcanization molded products capable of effectively sealing a carbon dioxide refrigerant without generation of blisters, etc. therein.

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Kanagawa, Japan

Masashi Kudo