Process for the precipitated silica new precipitated silicas containing zinc and their use for the reinforcement of elastomers

Abstract

The invention relates to a new process for the preparation of precipitated silica which has a good dispersibility and very satisfactory reinforcing properties. It also relates to new precipitated silicas which are in the form of powder, of substantially spherical beads or of granules, these silicas being characterized by the fact that they have a CTAB specific surface of between 90 and 250 m.sup.2 /g, a BET specific surface of between 90 and 250 m.sup.2 /g, a DOP oil uptake lower than 300 ml/100 g, a zinc content of between 1 and 5% by weight, and by the fact that the number N of stearic acid molecules consumed per nm.sup.2 of silica surface, when stearic acid is reacted with this silica in xylene for 2 hours at 120.degree. C., is at least 1. The invention also relates to the use of the said silicas as reinforcing fillers for elastomers, especially for improving their rheological properties.

Dependencies are inferred from the claim text.