Japan Synthetic Rubber Co., Ltd.

Isao Sugita

Fumio Tsutsumi

Isao Furuta

Itsuki Umeda

Yoji Mori

Masato Sakai

Makoto Kondo

Ryuzo Fujita

Masao Hirano

Kazuo Kimura

A rubber composition obtained by subjecting a mixture of (I) 35-95 parts by weight of a fluoroelastomer, (II) 65-5 parts by weight of at least one member selected from the group consisting of polyethylene, ethylene-vinyl acetate copolymer and ethylene-unsaturated carboxylic acid ester copolymer, and an organic peroxide to reaction while imparting shearing deformation to the mixture. A crosslinkable rubber composition can be obtained by compounding the above rubber composition with a crosslinking agent for the fluoroelastomer (I). The above rubber composition is superior in processability, particularly extrusion-processability, sealing property, heat resistance, steam resistance and weather resistance.

Rubber composition and crosslinkable rubber composition

A rubber composition comprising 100 parts by weight of a rubber component which comprises at least 30% by weight of an emulsion polymerization rubber which is a conjugated diene polymer rubber or conjugated dienestyrene copolymer rubber obtained by emulsion polymerization, has a bound styrene content of 0-65% by weight, contains 20-35% by weight of a component having a molecular weight of not more than 150,000 as measured by a gel permeation chromatography and has a Mooney viscosity, ML.sub.1+4 (100.degree. C.), of 60-160 and a Mooney viscosity difference (.DELTA.MV) of -20 to +5 as defined by the following equation:

Process for preparing a rubber composition having two different

A thermoplastic elastomer composition consisting essentially of (A) 2 to 50% by weight of a polybutadiene having a 1,2-addition unit content of 70% or more, (B) 20 to 90% by weight of an olefinic rubber and (C) 5 to 60% by weight of a polyolefin resin, 30 to 95% by weight of the total polymer components, up to 90% by weight of said polybutadiene and up to 90% by weight of said olefinic rubber being soluble in Tetralin when the composition is heated at 210.degree. C for 3 hours in Tetralin under reflux. Said composition is excellent in mechanical strength, weather resistance, oil resistance, heat stability and processability and has a small permanent set.

Thermoplastic elastomer composition

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Suzuka, Japan

Isao Sugita