METHOD FOR PREPARING PRECIPITATED SILICON DIOXIDE, PRECIPITATED ZINC-CONTAINING SILICON DIOXIDES, AND USE THEREOF OF REINFORCING ELASTOMERS Russian patent published in 1999 - IPC

FIELD: chemical industry. SUBSTANCE: silicon dioxide is prepared by reacting alkali metal silicate with acidifying agent using zinc compound and subsequently separating and drying the product. The reacting silicon dioxide has specific surface of 90-250 sq.m/g, oil absorption of lower than 300 ml/100 g. Pore distribution is such that pore volume formed by pores with diameters of 175-275 is less than 50% of pore volume formed by pores with diameters less or equal to 400 ; zinc content is 1-5 wt %; number of silicon dioxide surface, when stearic acid is made to react with said silicon dioxide in xylene at 120 C for 2 hours. The resulting silicon dioxide makes it possible to obtain satisfactory rheological properties of elastomer and improve mechanical properties thereof. EFFECT: improved rheological properties of elastomers. 39 cl, 3 ex, 4 tbl