Partially hydrophobic precipitated silicas.

摘要

Partially hydrophobic precipitated silica with a methanol crosslinking potential of 10-49% is new. When anhydrous, the silica has a DBP absorption > 250 g/100 g. The average particle size is 1-12 mu m and the silica has a carbon content of 0.3-1.85 %, and when dried, it loses 2.6-10 % of its weight. It has a pH of 5.5-10. The silica is prepared by mixing a silica suspension (which has been prepared using known methods) with a material that gives the silica hydrophobic properties. The mixing takes place for a very short time at conditions of low pH and high shear. The resulting suspension is filtered and washed in salt-free conditions, and the filter cake is dried, thermally treated and powdered.