Abstract: 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.

Abstract: A silicone-based composite rubber composition having good processability on rolls which is obtained by compounding a rubber-forming polymer (A) comprising a polyorganosiloxane and an organic rubber, a silicon compound (B) having at least two hydrolyzable groups per molecule which are able to undergo hydrolysis and condensation reactions with silanols, and a heavy metal compound, amine, or quaternary ammonium salt (C) which catalyzes the hydrolysis and condensation reactions, and allowing the resulting formulation to undergo hydrolysis and condensation reactions while the formulation is kept being deformed by shearing; a crosslinkable, silicone-based composite rubber composition comprising the silicone-based composite rubber composition having blended therewith an organic rubber-crosslinking agent; and an oil seal and a rubber hose both obtained from the crosslinkable, silicone-based composite rubber composition.

Abstract: A rubber composition obtained by compounding (B) from 0.005 to 50 parts by weight of an polyorganohydrogensiloxane and (C) from 0.00001 to 1 part by weight of a compound of a transition metal belonging to the group VIII with (A) 100 parts by weight of a rubber-forming polymer mainly comprising (I) from 3 to 70% by weight of a polyorganosiloxane represented by the formula: ##EQU1## wherein R represents a substituted or unsubstituted monovalent organic group, 0.02 to 10 mole % of which being a vinyl group; and a represents a number of from 1.900 to 2.004,and having a degree of polymerization of from 500 to 10,000 and (II) from 30 to 97% by weight of organic rubber, and subjecting the resulting compound to hydrosilylation while effecting shear deformation. The rubber composition is excellent in roll processing properties, mechanical strength, heat resistance, and low-temperature property and is suitable as oil seal and rubber hose.

Abstract: A rubber composition that is prepared by reacting an organic peroxide, under shear deformation, with 3-70 parts by weight of silicone rubber (I), 30-97 parts by weight of a saturated elastomer (II) that substantially fails to be crosslinked with an organic peroxide when it is used alone, and 0-20 parts by weight of another elastomer (III) that is co-crosslinkable with component (I) in the presence of an organic peroxide and which is also co-crosslinkable or highly miscible with component (II) [where (I)+(II)+(III)=100 parts by weight].

Abstract: A rubber composition obtained by subjecting a mixture of (I) 35-95 parts by weight of a fluoroelastomer and (II) 65-5 parts by weight of an ethylene-.alpha.-olefin copolymer rubber in which the total of the (I) component and the (II) component is 100 parts by weight and a crosslinking agent for the ethylene-.alpha.-olefin copolymer rubber (II) to reaction while imparting shearing deformation to the mixture. Said rubber composition is excellent in processability on roll and in extruder, heat resistance, steam resistance, weather resistance, compression set and resistance to compressive load. A rubber article is obtained by subjecting the above rubber composition and a crosslinking agent for the fluoroelastomer (I) and optionally at least one additive to reaction, said rubber article being excellent in heat resistance, weather resistance, compression set and resistance to compressive load and hence can be used in the fields of general industry, electric industry and chemical industry.