PROPERTIES AND USES OF CARBON BLACK

The important properties of carbon black are particle size, surface area, and pH. These properties are functions of the production process and the feed properties. Channel blacks are generally acidic, while those produced by the Furnace and Thermal processes are slightly alkaline.

The pH of the black has a pronounced influence on the vulcanization time of the rubber. (Vulcanization is a physicochemical reaction by which rubber changes to a thermosetting mass due to cross-linking of the polymer chains by adding certain agents such as sulfur.) The basic nature (higher pH) of furnace blacks is due to the presence of evaporation deposits from the water quench. Thermal blacks, due to their larger average particle size, are not suitable for tire bodies and tread bases, but they are used in inner tubes, footwear, and paint pigment. Gas and oil furnace blacks are the most important forms of carbon blacks and are generally used in tire treads and tire bodies. Table 1.1 shows a typical analysis of carbon black from an oil furnace process.

Carbon black is also used as a pigment for paints and printing inks, as a nucleation agent in weather modifications, and as a solar energy absorber. About 70% of the worlds’ consumption of carbon black is used in the production of tires and tire products. Approximately 20% goes into other products such as footwear, belts, hoses, etc. and the rest is used in such items as paints, printing ink, etc. The world capacity of carbon black was approximately 17 billion pounds in 1998.13 U.S. projected  onsumption for the year 2003 is approximately 3.9 billion pounds.

Table 1.1: Selected properties of carbon black from an oil furnace process