A method for continuous monitoring of bond formation between rubber and reinforced wire

The integrity of a high performance, steel-belted tire is heavily dependent on the adhesion of steel reinforcement to rubber. A bronze coating, having a nominal composition of 98.5% Cu (the balance being Sn), is plated on tire bead wire to promote adhesion of the steel reinforcement to rubber. Pull-out force is the current standard for evaluating adhesion as recommended by ASTM. This paper describes an in-situ, continuous monitoring system designed to detect the rate of adhesive bond formation between rubber and steel reinforcement during the vulcanization process. Parameters such as oxide chemical structure and thickness were investigated to assess the rate of bond formation during vulcanization and their effect on adhesion. Results proved that this monitoring technique is an efficient, reproducible, and reliable technique for studying the interfacial interactions occurring between steel reinforcement and rubber during vulcanization.