| abstract |
A precipitated silica with the following physicochemical properties: n BET surface area 35 m 2 /g to 350 m 2 /g BET/CTAB surface area ratio 0.8 to 1.1 Pore volume, PV 1.6 ml/g to 3.4 ml/g Silanol group density 3 ml/(1.5 g) to 9.5 ml/(1.5 g) (V 2 = NaOH consumption) Average aggregate size 250 nm to 1500 nm CTAB surface area 30 m 2 /g to 350 m 2 /g DBP value 150 ml/100 g to 300 ml/100 g V 2 /V 1 by Hg porosimetry 0.19 to 0.46 DBP/CTAB 1.2 to 3.5 nis produced by reacting alkali silicate with mineral acids at temperatures of 60° C. to 95° C. while maintaining a pH of 7.5 to 10.5 and continuously stirring, continuing the reaction to a solids concentration in the precipitation suspension of 90 g/l to 120 g/l, adjusting the pH value to a value of less than or equal to 5, filtering out, washing, drying and optionally grinding or granulating the precipitated silica. The precipitated silica is used as a filler in vulcanizable rubber compounds and vulcanizates. |