GB1101411A - Vulcanizable compositions - Google Patents

Abstract

Vulcanized elastomers are prepared by heating a composition comprising a synthetic rubbery polymer having groups which under the vulcanization conditions employed are hydrolysable to carboxylic acid groups, an organic peroxide, and an oxide or hydroxide of an alkaline earth metal or lead monoxide. Other vulcanizing agents such as sulphur may be employed in addition to the peroxide, e.g. dicumyl peroxide. The rubbery polymer may be a copolymer of an unsaturated hydrocarbon, e.g. ethylene, propylene, styrene or butadiene, with an alkyl, cyanoalkyl or aralkyl ester of an unsaturated carboxylic acid, e.g. acrylic, methacrylic, sorbic or itaconic acid; maleates or fumarates may be used in minor amounts in styrene copolymers. Acrylonitrile may additionally be included in the rubbery polymer. Suitable alkaline earth metal (hydr)oxides include MgO, CaO, SrO, Ca(OH)2, Sr(OH)2 and Ba(OH)2. Optional ingredients which may be present include fatty acids, e.g. stearic acid, antioxidants, e.g. isopropylamino - diphenylamine and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, fillers, e.g. carbon black or metal oxide or hydroxide, extenders, e.g. mineral oils with a high paraffinic, naphthenic or aromatic content, process oil and other polymers. Examples illustrate the vulcanization of butadiene -styrene - methyl acrylate, butadiene-methyl methacrylate and butadiene-styrenemethyl methacrylate copolymers.