Technical field, hydrophobic silica has pharmacological improved

摘要

Precipitated silica characterized in that it has an index of methanol is greater than 20, preferably greater than 25, a luminance y greater than 84, a bet specific surface area greater than 50 m * * 2 / g, a mean particle size ranging from 0,1 and 20 microns and in that it is processed by a mixture of octamethylcyclotetrasiloxane hexamethylcyclotrisiloxane d3 and d4, in the absence of a tin compound. / p & & p & hve compositions containing such silicas and elastomers (vulcanized rubber compositions) obtained with these compositions.