Overview of the foreign white carbon black market  Silica began to be industrialized during World War II. The world's silica production capacity was 475,000 tons in 1974, 570,000 tons in 1978, 800,000 tons in 1990, and 1 million tons in 1997. The average annual growth rate from 1990 to 1997 was about 3.2%. In 1997, the production capacity of precipitation method silica is about 900,000 tons, and vapor method silica is about 100,000 tons.
    The main manufacturers of precipitated silica are Degussa in Germany, Rhodia in France, PPG in the United States, Akzo in the Netherlands, Deshan Soda and Silica in Japan. The fumed silica is mainly produced by Degussa and Cabot.     Silica is usually classified according to its surface area and use. Appendix E of the International Standard 150794-1:1994 Rubber Compounding Agent Precipitated Hydrated Silica" stipulates the classification of precipitated silica and its typical physical and chemical properties. The classification is based on the surface area of white carbon black into 6 categories, such as A, B, C, D, E, and F, but unlike carbon black, the specific name of each species is given.


  Therefore, major foreign manufacturers have classified their products according to their surface area, dosage form, powder, granular, agglomerate, and use, and given the product name and brand. Generally, each manufacturer’s white carbon for rubber or non-rubber There are more than 10 varieties or grades of black.
    The surface area of precipitated silica reflects the size of its primary particles and is the main indicator that affects its application performance. Generally speaking, the smaller the particle, the larger the surface area, and the better the reinforcing effect in rubber. However, when the surface area is too large, the cohesion between the particles will increase, which is not easy to disperse in the rubber compound, making the rubber compound more viscous during processing. High heat generation, easy to scorch; on the other hand, it will adsorb more accelerators, accelerate the decomposition of accelerators, and extend the curing time. In addition, if the surface area is too large, the process may be improperly controlled during the formation of white carbon black. There is silicone gel in the product. At this time, although the surface area is large, the reinforcing effect will decrease. Therefore, the surface area of precipitated silica for rubber shoes and rubber products is generally 170~19om2/g, and the surface area of precipitated silica for tires is generally 140-17Om2/g. However, after improving the generation and granulation process of precipitation method to enhance its dispersibility, new varieties with larger surface area (80~250m2/g) and better reinforcement and dispersibility have been developed. The precipitation method silica with a larger surface area of 190~25om2/g, or higher than 300m2/g) is suitable for thickening coatings and inks, and can also be used in silicone rubber products instead of vapor-phase silica; the surface area is 100~ The 14Om2/g variety is suitable for general rubber products such as shoe soles; the precipitation method silica with a lower surface area of 35~60m2g) is suitable for high-elastic extruded rubber products.
    There is no international standard for fumed white carbon black. Each manufacturer has its own series of varieties, which are generally classified by surface area. There are also hydrophobic varieties that have been post-treated with silane, and the products are all powdery.
    Footwear is the largest user of precipitated white carbon black. Its consumption ratio reached 45% in 1980. Due to the rapid growth of the tire industry, it had dropped to 40% in 1990.
    Foreign forecasts predict that the growth rate of precipitation method silica will be 4%, and the main growth will come from the new demand of the tire industry.
    In the tire industry, in the past, precipitation method silica was mainly used in the belt layer of radial tires to enhance the adhesion between steel wire and rubber and the tread of radial truck tires to improve the puncture resistance and chipping resistance of the tread. Its dosage is small, generally 10-15 servings. In recent years, due to the increasingly stringent requirements for environmental protection and energy saving, the use of precipitation silica for tire tread rubber can significantly reduce the rolling resistance of tires, while maintaining good ice and wet resistance, and its wear is only Slightly lower. In 1990, Michelin had produced green tires using all precipitation method white carbon black. Its rolling resistance was about 30% lower than that of ordinary tires, and its fuel-saving and automobile exhaust gas effects were significant. However, precipitation method white carbon black is sold abroad. The price is about 140% of carbon black, coupled with the increased cost of coupling agent and rubber material processing, the tire cost has also increased significantly. Therefore, currently in the production of low rolling resistance tires, carbon black and precipitation white carbon are mostly used Black and black formulations are used to achieve the best performance and cost effect. In Europe, because people pay special attention to the application performance of tires, and use winter tires with good ice resistance and wet skid resistance in winter, in 1997, precipitation The largest amount of white carbon used in passenger tires has reached 65% of the reinforcing filler, and the largest amount used in the tread of truck tires is 15%. European tire manufacturers have used precipitation method white carbon black to reach 8% per year. Ten thousand to ten thousand tons, and will grow rapidly.
    The amount of precipitated silica used in treads in the United States and Japan is less than in Europe. Due to the large size of the cars used in the United States, straight roads, slower speeds, and cheaper gasoline, the requirements for high-performance tires with low rolling resistance, ice resistance, and wet skid resistance are not as urgent as in Europe.
    There are three different forecasts for the rubber industry’s demand for white carbon black by 2005.