GB581089A - Improvements relating to vulcanizable compositions and methods of making the same - Google Patents

Abstract

Synthetic rubber which resists the dispersion therein of elemental sulphur is compounded for vulcanization with a stable sulphur compound of a partly unsaturated hydrocarbon oil, tar asphalt, extract of acid sludge or the like, boiling above 160 DEG C. at 12 mm. mercury pressure, and containing sufficient fixed sulphur to effect the covulcanization of the hydrocarbon and the synthetic rubber. A suitable sulphur containing compound is described in Specification 580,189, according to which, a hydrocarbon consisting of approximately 90 per cent. carbon, and 10 per cent. hydrogen is heated with sulphur to a temperature above the melting point of sulphur, e.g., 190 DEG -215 DEG C. until at least 3 per cent., preferably 5 per cent. of the weight of the final product, of sulphur has been evolved as hydrogen sulphide. Compounds containing 6-10 per cent. of fixed sulphur are preferred.ALSO:Synthetic rubber which resists the dispersion therein of elemental sulphur, is compounded for vulcanization with a stable sulphur compound of a partly unsaturated hydrocarbon oil, tar, asphalt, extract of acid sludge or the like boiling above 160 DEG C. at 12 mm. mercury pressure, and containing sufficient sulphur to effect the covulcanization of the synthetic rubber and the hydrocarbon. A suitable sulphur-containing compound is described in Specification 580,189, according to which a hydrocarbon consisting of approximately 90 per cent. carbon and 10 per cent. hydrocarbon is heated with sulphur to a temperature above the melting point of sulphur, e.g., 190-215 DEG C. until at least 3 per cent., preferably 5 per cent. of the weight of the final product, of sulphur has been evolved as hydrogen sulphide. Compounds containing 6-10 per cent. of fixed sulphur are preferred. In compounding the synthetic rubber, the amount of the compound to be added is calculated on the amount of sulphur required to vulcanize the hydrocarbon, about 3-6 per cent., in addition to that required by the rubber. The product is particularly useful in the vulcanization of co-polymers of butadiene, e.g., with styrene or acrylonitrile. According to an example, 100 parts of Hycar OR, 0.5 parts of stearic acid, 25 parts of a compound of acid sludge extract boiling at 250-280 DEG C. at 12 mm. mercury, containing 10 per cent. of fixed sulphur, 1.5 parts of accelerator, 50 parts of Channel black, and 5 parts of zinc oxide are vulcanized to a soft product at 45 lbs. steam pressure for 30 minutes.