Fine-Particle Silicas in Tire Treads, Carcass, and Steel-Belt Skim

Abstract

Abstract HS-200 silicas, modified with the coupling agents, performed in tire treads equivalent to N-200 type carbon blacks. Tread wear and traction in contemporary tire tread compounds could be obtained with HS-200 silica equivalent to those with carbon black. In passenger-car treads containing higher than normal butadiene rubber, HS-200 silica could be compounded for excellent mileage and improved wet road traction. These results are encouraging, but considerably more tire testing would be required for absolute certainty that silicas could, in fact, replace contemporary tread fillers. The data indicate that silicas together with silane coupling agents provide extreme flexibility in the design of tread properties. Although tested only to a limited extent in tires, silicas can be used in sidewall, carcass, and radial-belt compounds of tires, as well. The various filler sizes available, and the flexibility of adjusting surface activity, permits a wide range of rubber properties to be obtained. In a limited number of cases, these properties are virtually identical to those obtained with contemporary carcass and sidewall fillers. Tire performance in carcass and belt-skim compounds showed that silicas could provide tire performance equivalent to conventional fillers in these applications. Based on our observations, we confidently believe the technology exists to meet the performance of today's tire components entirely with inorganic fillers. Obviously, to put these components together in a practical tire requires some development work. Satisfactory performance in individual components is encouraging, but the incorporation of all components into a single harmonious product is still necessary. Fine-particle silicas are truly oil-independent fillers that can be used for tires as well as other quality rubber products.