Prepn. of finely divided silica e.g. for polymer chemistry, paints - by reacting alkali silicate solns. with acids or acid-type reagents

摘要

Prepn. of finely divided silica comprises reaction of alkali silicate solns. with acids or acid-type reagents, circumventing a coherent hydrogel structure. The alkali silicate soln. is neutralised at 80-100 deg.C, treated with a trialkylbenzylammonium type cpd., at the point where the viscosity of the sol phase is 10-14 mPals, to form monodisperse floc-agglomerates, conc. and worked up. USE/ADVANTAGE - Finely divided silica is used as a filler for polymer work-up, a thickener or thixotropic agent for various systems, a mobile solvent for bulk materials, or extender for dispersion paints or a carrier for biologically active materials. The process is economical and the pptn. is easier to control than in prior-art processes