Highly structured finely divided silica prepn. - useful e.g. as filler and barrier in rubber, paint, paper pesticide and pharmaceutical industries

摘要

Prepn. of highly structured, finely divided silica comprises reaction of alkali silicate solns. with acids or acid type materials with mixing by stirring or action of high shear strengths. Prior to reaching an electrolyte concn. of 0.3N trialkyklbenzyl (or H)-ammonium (as cationic surfactant) is added in a concn. such that coagulation takes place below the critical micelle-forming concn. of the surfactant. Pref. the ratio of surfactant to SiO2 in the sol-phase is 1:80-100 and 1:400-500 in the entire process. USE/ADVANTAGE - Finely divided silica is used as a filler for the rubber industry, an extender-filler for dispersion paints and paper coatings as a mobile solvent, as an antiblocking agent or a carrier for pesticides, pharmaceuticals or cosmetic ag