Abstract: The polymeric ingredient of the inventive rubber composition is an acrylic polymer modified with a mercapto-containing organopolysiloxane as prepared by the emulsion polymerization of an acrylic monomer in an aqueous emulsion of the organopolysiloxane. Characteristically, the acrylic monomer is copolymerized with another monomer having an active halogen atom or an epoxy group. By virtue of this unique formulation of the rubbery polymer, the inventive rubber composition prepared by compounding the rubbery polymer with a reinforcing filler and a specified curing or crosslinking agent can be vulcanized to give a vulcanizate having excellent mechanical properties, heat resistance, oil resistance and cold resistance as a combination of the features of silicone rubbers and acrylic rubbers.

Abstract: An acrylic rubber composition is proposed which is improved in respect of the extrusion-moldability as well as the surface slipperiness of the vulcanized article obtained therefrom. The composition comprises (a) an acrylic rubbery cooplymer which is a copolymer of a (meth)acrylic ester and a coolymerizable organosilicon compound having a silicon-bonded vinyl group in a molecule, (b) a reinforcing filler, (c) a powder of spherical particles having a specified average particle diameter and (d) an organic peroxide as a vulcanizing agent. The composition can be compounded further with a blowing agent to give a foamable rubber composition capable of being vulcanized into a spongy rubber body exhibiting excellent feeling on touch and slipperiness in contact with human skin to be useful, for example, as a material of cosmetic puffs.

Abstract: A rubber composition based on a rubbery polymer and a silica-based reinforcing filler can be imparted with a greatly improved workability in roll milling and molding as well as in the mechanical properties of the vulcanizates prepared therefrom when the rubber composition is admixed with an acetylene alcohol or an alkylene-oxide adduct of acetylene alcohol presumably by virtue of the improvement in the dispersibility of the reinforcing filler in the rubbery matrix. The improvement obtained by the addition of the acetylene alcohol compound is not limited to the dispersibility of silica fillers but also to the dispersibility of carbon black when the rubbery polymer is an organopolysiloxane-modified acrylic polymer.

Abstract: Rubber vulcanizates having excellent oil resistance, heat resistance and cold resistance can be obtained from a rubbery copolymer which is a polymerization product of an acrylic monomer mixture of which the essential components are an organosiloxy-containing acrylate compound such as acryloxymethyl pentamethyl disiloxane and 3-acryloxypropyl pentamethyl disiloxane and an epoxy group- or halogen-containing monomer such as allyl glycidyl ether, glycidyl methacrylate and vinyl chloroacetate, optionally, with addition of an acrylate ester monomer such as ethyl acrylate, n-butyl acrylate and 2-methoxyethyl acrylate.

Abstract: The inventive copolymer composition is satisfactorily curable or vulcanizable into, for example, a rubbery elastomer even by an organic peroxide contained therein as a crosslinking agent. The crosslinkable copolymer comprised therein is a polymer having, in a molecule, at least two monomeric units each having a vinyl-containing organosilicon pendant group represented by the general formula (Vi.sub.m R.sup.1.sub.n SiO).sub.a Vi.sub.b R.sup.2.sub.c Si--, in which Vi is a vinyl group, R.sup.1 is a hydrogen atom or a group selected from the class consisting of monovalent hydrocarbon groups free from aliphatic unsaturation, hydroxy group and hydrolyzable groups excepting halogen atoms, R.sup.2 is a hydrogen atom or a monovalent hydrocarbon group, m is 1, 2 or 3, n is zero, 1 or 2, a is 1, 2 or 3, b is zero, 1 or 2 and c is zero, 1 or 2 with the proviso that a+b=1, 2 or 3 and a+b+c=3.