GB420334A - Process for the preparation of a plastic vulcanisable material from rubber, gutta-percha, balata, and the like - Google Patents

Abstract

A process for the preparation of a plastic vulcanizable material from non-adhesive powder of non-vulcanized rubber, guttapercha, balata or the like obtained by spray-drying latex with a substance which protects the dried particles against agglomeration, e.g. as described in Specification 388,341, consists either in adding compounding ingredients, such as fillers, vulcanizing agents and accelerators, in the dry state to the dry powder and in rendering the mixture plastic by slight mechanical action, such as by rolling, kneading or pressing, or in mixing the compounding ingredients with the powder dispersed or dissolved in a swelling agent for the rubber, e.g. benzene, petroleum or other mineral oils, the mixture being rendered plastic merely by the swelling action on the rubber, or by a combined swelling and slight mechanical action. The resulting paste may be spread, plastered or sprayed to the desired shape and vulcanized. The compounding ingredients may be first emulsified or dispersed in a swelling liquid, and this emulsion or dispersion mixed with the powder, e.g. by rolling or spraying. Latex like suspensions may be made by adding water or other liquid. The swelling agent may be a normally solid material which melts at or below the vulcanizing temperature. Preferably a substance which when molten dissolves sulphur is used, e.g. naphthalene. Specification 316,006, [Class 70], also is referred to.