Adhesion between Rayon and Nylon cord and an elastomer matrix

Abstract

Two types of cord, namely Nylon and Rayon, with variation in the number of twists per inch in a natural rubber (NR) compound with and without a dry-bonding system are considered. The dip systems used for the cords are based on resorcinol formaldehyde latex with three latex systems: NR/VP, SBR/VP and XSBR/VP. The natural rubber/vinyl pyridine latex system gives rise to higher bond strength, and carboxylated styrene butadiene rubber/vinyl pyridine latex system to a lower bond strength. As the number of twists increases, the adhesion value increases for both Nylon and Rayon cords. The adhesion is further enhanced by the incorporation of the dry-bonding system in the compounds. Flex life improves as the number of twists increases, and is further enhanced by the use of a NR/VP latex dip system and the dry bonding system. However, with highly twisted cords, breakage of the cords is observed under cyclic tension stress. SEM studies reveal that the low flex life of the less twisted cord composites is probably due to the lower adhesion values and fibrillation under cyclic stress. Improved flex life and adhesion of the highly twisted cords may be due to the more mechanical anchorage of the cords in the elastomeric matrix.