The Mechanism of the Action of Vulcanization Accelerators. Derivatives of Mercaptobenzothiazole. II. The Transformation of Mercaptobenzothiazyl Sulfide

Abstract 1. During the vulcanization of rubber, mercaptobenzothiazyl sulfide is transformed into mercaptobenzothiazole and the zinc salt of the latter. 2. This transformation is effected by the interaction of mercaptobenzothiazyl sulfide with sulfur. As a result of this reaction unstable products of addition of sulfur and mercaptobenzothiazyl sulfide are formed, and when heated these are converted into benzothiazyl disulfide. 3. During vulcanization, benzothiazyl disulfide decomposes into mercaptobenzothiazole and the zinc salt of the latter. 4. The acceleration of vulcanization of rubber by mercaptobenzothiazyl sulfide, as well as by other derivatives of mercaptobenzothiazole in which the mercapto —SH group is substituted, is attributable to several causes, the chief of which is the formation of mercaptobenzothiazole and its zinc salt.