| 摘要 |
chemistry of polymers. SUBSTANCE: method comprises reacting silicate with acidifying agent to give precipitated silica solution and subsequently and drying said suspension. Precipitation is carried out as follows: original blend containing some amount of total amount of silicate which is essential for reaction, and at least one electrolyte for concentration of silicate (calculated for SiO2) varied from 55 to 60 g/l; acidifying agent is added to adjust pH of reaction mixture to 7-8.5 acidifying agent is added to reaction mixture and the remaining amount of silicate is optionally added simultaneously, the whole is separated by filtration, washing and pressing by admitting air at pressure of lower than 4.5 bar for 20-40 seconds, and the whole is dried by spraying suspension which contains less than 17 wt % of dry material. New precipitated silica has the following characteristics: specific surface BET varies from 185 to 250 sq.m/g, specific surface CTAB varied from 180 to 240 sq.m/g; such pore distribution wherein volume of pores V2 is less than 50% of volume V1 formed by pores having diameter of less or equal to 400 A, volume of pores (Vd1), formed by pores having diameter less than 1 mcm is greater than 1.65 cubic.cm/g, grain size is 20-100 A, percentage of fines (tauf), after ultrasound deagglomeration, is at least 50%. The resulting product has sufficient ability of being dispersed in elastomers and has good reinforcing properties. EFFECT: improved properties of the precipitated silica. 25 cl, 6 ex, 4 tbl |
