Process for the preparation of precipitated silica, precipitated silicas thus obtained, and their use in the reinforcement of rubbers

摘要

A process for the preparation of precipitated silica having an aptitude for dispersion and improved reinforcing properties. The invention also relates to new silicas which exist in the form of granules, powder or substantially spherical balls, these silicas being characterised in that they have both a BET specific surface and a CTAB specific surface of between 140 and 200 m2/g, and in that the porous volume constituted by the pores with diameters between 175 ANGSTROM and 275 ANGSTROM represents at least 50 % in the case of powders and balls, and at least 60 % in the case of granules, of the porous volume constituted by the pores with diameters less than or equal to 400 ANGSTROM . Additionally, the granules have a degree of attrition which is less than 20 %, the powder which is a DOP oil uptake of between 180 and 350 ml/100 g, and the balls a mean size of at least 80 mu m. The invention also relates to the use of the said silicas as reinforcing fillers for plastics (elastomers).