Method of preparation of new vulcanized rubber compositions of butyl rubber and of a solid polyethylene

摘要

A blended mixture of 5 to 95 parts of a solid homopolymer of ethylene or of a C3 to C5 alpha-mono-olefin, 95 to 5 parts of a rubbery copolymer of isobutylene and at least one C4 to C14 diolefinic hydrocarbon containing 80-99.9 mol. per cent isobutylene, and 0.1 to 3 parts of a halomelamine is masticated at 120-200 DEG C. for 1 to 30 minutes, the temperature lowered to a point where vulcanization of the isobutylene copolymer is negligible, a vulcanizing agent for the copolymer added and the blend shaped and vulcanized. Trichloromelamine is the preferred halomelamine. Metal compounds e.g. zinc oxide (preferred), zinc sulphate or sulphide and lead or magnesium oxide may also be present. The usual vulcanization additives may also be present. The products may be used as wire and cable covers.