Abstract: The invention provides a highly flame-retardant polyolefin-based rubber composition free from the problem of the formation of toxic or corrosive gases and a large volume of smoke by burning of conventional flame-retardant rubber compositions impregnated with a large amount of a halogen-containing flame retardant agent. The inventive rubber composition comprises (a) a synthetic rubber of polyolefin type, (b) an organopolysiloxane resin which is preferably formed of monofunctional siloxane units and tetrafunctional siloxane units in a molar ratio of 0.6/1.0 to 2.0/1.0, (c) red phosphorus and (d) aluminum hydroxide or magnesium hydroxide in a specified proportion.

Abstract: The invention provides a novel rubber composition based on an ethylene-propylene copolymeric rubbery elastomer and curable by hot air vulcanization under atmospheric pressure giving great advantages over conventional ones vulcanizable only under pressure. The inventive rubber composition comprises, in addition to the ethylene-propylene copolymeric rubbery elastomer, an oganopolysiloxane gum having alkenyl or mercapto groups in the molecule, a reinforcing silica filler, an organic compound having at least two maleimido groups in a molecule and a curing agent which is an organic peroxide or an organic sulfur compound.

Abstract: Rubber compositions curable to rubbery elastomers by heating are provided, in which co-vulcanization of an organic rubber, e.g. natural rubber or an organic synthetic rubber and an organopolysiloxane rubber can be effected to a satisfactory degree, whereas such co-vulcanization in the prior art involves several difficult problems. The characterizing components in the rubber composition are the organopolysiloxane which has at least two functional units of either mercapto groups or aliphatically unsaturated linkages in the molecule and a specific organosilicon compound which has a polysulfide linkage and one or more silicon-bonded hydroxy groups or hydrolyzable atoms or groups in the molecule.

Abstract: The invention provides a novel elastomer composition capable of giving vulcanized rubber products with superior solvent resistance, oil resistance, heat resistance and other properties. The composition is formulated with a polymer blend of an ethylene-propylene copolymeric elastomer and a specific organopolysiloxane having certain amount of mercapto-substituted organic groups bonded to the silicon atoms as the base component admixed with a filler and a crosslinking agent or a vulcanizing agent.