| abstract |
A PARTIALLY HYDROPHOBIC PRECIPITATED SILICA, CHARACTERISED BY A METHANOL WETTABILITY OF 10 TO 49 , IN PARTICULAR WITH A DBP UPTAKE ANHYDROUS OF GREATER THAN 250 G/100 G AND A MEAN PARTICLE SIZE OF 1 TO 12 µM AND/OR A CARBON CONTENT OF 0.3 TO 1.85 AND/OR A LOSS ON DRYING OF 2.6 TO 10.0 AND/OR A PH VALUE OF 5.5 TO 10.0, IS PREPARED BY MIXING THE AMOUNT OF WATER-REPELLENT AGENT WITH THE PRECIPITATED SILICA SUSPENSION AT VERY SHORT RESIDENCE TIME AND LOW PH VALUE, FILTERING OFF THE SOLID SUBSTANCE, WASHING FREE OF SALT, DRYING, POST-TREATING THERMALLY AND MILLING. THE PARTIALLY HYDROPHOBIC PRECIPITATED SILICA CAN BE USED IN ACTIVE SUBSTANCE FORMULATIONS AND ACTIVE SUBSTANCE FORMULATIONS OF HYDROLYSIS-SENSITIVE SUBSTANCE AND IN DE FOAMING AGENTS. |