Use of Nonblack Fillers in Tire Compounds

Abstract

Abstract A variety of nonblack fillers are used in the rubber components of tires. Calcium carbonate, clay, precipitated silica, talc and titanium dioxide are used in white sidewall compounds to impart desired physical properties and appearance. Precipitated silica can be used in black sidewall compounds, including nonstaining EPDM black sidewalls, to significantly improve tear strength, cut-growth resistance and resistance to ozone aging. Precipitated silica is used extensively in wire coat compounds in conjunction with resorcinol and methylene donating resins, and can be used with organocobalt salts to improve adhesive properties, tear strength and cut-growth resistance. Calcium carbonate, clay, mica and talc are found in innerliner compounds, and precipitated silica can be used. Precipitated silica is used in the treads of off-the-road tires such as earthmover tires, in order to improve tear strength and cut-growth resistance. Clay and talc can be used in tire treads. Precipitated silica is also used in the treads of tires of vehicles used for highway driving, such as passenger cars and trucks, in order to reduce the rolling resistance and increase the wet traction of the tire. It is necessary to modify the surface of precipitated silica with a bifunctional organosilane coupling agent in order to maintain tire treadwear for highway vehicles. Figures 16 and 17 are pictorial summaries of the use of nonblack fillers and the benefits of using precipitated silica in the various components of tire compounds, respectively.