GB572268A - Improvements in plasticizing of vulcanized rubber scrap - Google Patents

Abstract

Vulcanized rubber scrap is plasticized by working mechanically under oxidizing conditions with an acid and a plasticizing sulphide having the formula RSxR1, where R and R1 are the same or different hydrocarbon radicals which may be substituted with other groups other than those conferring accelerating properties, and where x is an integer. The acid may be a higher fatty saturated on unsaturated acid such as stearic or oleic acid, or rosin acid may be used provided an antioxidant be added. Small amounts only are required, depending on the amount of zinc oxide and similar materials present in the scrap. The sulphides are non-accelerators of vulcanization and can be made by the action of sulphur chloride on phenols, naphthenes, or unsaturated compounds such as dipentenes. Suitable sulphides are p-tolyl, hydroxyl-phenyl, tolyl, or naphthyl, or bornyl mono-, di-, or tetrasulphides, naphthene sulphides and dipentene sulphide. The oxidation can be effected by atmospheric air or by the addition of small amounts of an oxidizing-agent such as benzoyl peroxide, hydrogen peroxide, or ammonium persulphate. The process should be carried out below about 180 DEG F. Small amounts of accelerators such as diphenyl-guanidine, di-o-tolylguanidine, or cyclohexylamine may also be added to assist plasticization. The products can be revulcanized, or can be used to replace new rubber or reclaimed rubber obtained by other processes.