Promotion of adhesion between bronze plated bead wire and rubber compound by coating the bronze surface with benzoic acid

摘要

Benzoic acid was found to be the most effective chemical to use as a promoter, offering improved adhesion stability as well as good initial and aging properties. A bead wire manufacturing technology, coating chemical getting adhesion promoting property on bronze plated surface of bead wire, was carried to improving the adhesion properties with rubber compound. Benzoic acid was one of three kinds of adhesion promoting chemicals tried in the initial adhesion test. It was superior to that of the conventional one and its adhesion stability at a 10 percent mole concentration solution (coated weight of 0.13g/kg) was considerably improved against other concentrations, such as 1 percent (0.04g/kg), 5 percent (0.1g/kg) and 20 percent (0.8g.kg). The effect of humidity aging was profound in terms of adhesion strength due to the reduced mechanical strength of rubber by humidity aging, but a marginal improvement in stability was observed in view of rubber coverage in the case of benzoic acid coating. Also, the benzoic acid shows a good performance for oxidation resistance under severe conditions of high temperature and humidity (60 deg C, 90 percent RH). Thus, this newly suggested bonding system can be a practical way to improve the adhesion stability of bead wire-reinforced rubber article, while maintaining the initial and aging adhesion properties.