Cobalt is used to enhance the adhesion of rubber and metal, have been generally accepted and widely used in radial tire and wire hose products. Cobalt salts can be individually added rubber as rubber and metal adhesion promoter. Due to differences in products and companies in terms of technology, in addition cobalt salt adhesion promoter directly, but there are plenty of companies using cobalt blue with a (white) usage of resin bonding system. But whether alone or with, either cobalt content of cobalt salt compound must be controlled. This is because from the tell on the bonding mechanism of compound high cobalt content, not only for generating a large number of non-active copper sulfide and catalyzed by polymer-accelerated ageing and low cobalt content, brass to activity of copper sulfide and sulfur, that he can't get a good bond. From the performance of the rubber itself, add a small amount (amount) of cobalt salt on adhesion is beneficial, but the high proportion of cobalt salt on adhesion after steam aging is not only harmful, after thermal aging on tensile properties of rubber compound also has a negative impact.