Composition of Vulcanizing System, Course of Vulcanization and Bond Strength of Plied-Up SBR

Abstract

Abstract Insufficient bond strength between individual plies, in particular between the breaker strip and tire tread, is one of the shortcomings of tires manufactured from SBR rubbers. For several reasons, one of which is the conditions in which such large articles as tires are vulcanized, the breaker strip contains a much more active vulcanizing system than the tread rubber. The vulcanization of these rubbers in a zone of direct contact is effected at virtually the same temperature. In considering the special features of the vulcanization of SBR rubber, as one which vulcanizes comparatively slowly, it was natural to expect that the different activities of the vulcanizing systems in joined plies condition a sharp difference in the course of vulcanization, which might affect the bond strength considerably. We therefore made a study of the effect of the composition of crosslinking system and kinetics of vulcanization on the bond strength of plied-up SKS 30 rubber.