GB778100A - Improvements in or relating to laminated articles - Google Patents

Abstract

Laminates consisting of alternate layers of a silicone rubber and of an organic rubber are made by co-vulcanizing superimposed layers of an organic rubber polymer in which there remains prior to co-vulcanization at least 0,5 per cent of residual double bond unsaturation, and an organopolysiloxane rubber polymer in which at least 0,01 mol. per cent of the polymer units has at least one alkenyl group attached to the silicon atom prior to vulcanization the remaining group or groups being either saturated hydrocarbon radicals, aryl hydrocarbon radicals, halogenated hydrocarbon radicals or a mixture thereof, there being on the average a total of 1,9-2,1 organic radicals per silicon atom. The organic rubber polymer may be obtained by polymerizing a diene e.g. butadiene, dimethylbutadiene, isoprene, chloroprene or by copolymerizing two or more dienes or by copolymerization of a diene with isobutylene, styrene, acrylonitrile, methylacrylate, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl carbazole, coumarone, indene or vinyl toluene. Examples of the alkenyl radicals used are vinyl, allyl, heptanyl and octadecenyl; of the saturated hydrocarbon radicals are methyl, ethyl, butyl, octadecyl and cyclohexyl; of the aryl hydrocarbons are phenyl, tolyl and xenyl and of the halogenated hydrocarbon are pentafluoroethyl, dichlorophenyl, trifluorovinyl, heptachloroxenyl, dibrompohenyl and chlorocyclohexyl. Many examples of covulcanizing agents; of fillers such as silica fillers and metal oxide fillers; of accelerators, of oxidation inhibitors and of activators are given. The layers may be extruded over one another either in flat or tubular form and reinforcing fabrics such as cotton, nylon, glasscloth or metallic wire mesh may be included in the layers or between them.