PROCESS FOR THE MANUFACTURE OF PULVERULENT, FREE- FLOWING RUBBER MIXTURE

摘要

An improved process for manufacturing a pulverulent, free-flowing rubber mixture comprises mixing an aqueous emulsion of a rubber solution with an aqueous dispersion of a filler, and introducing this mixture into water containing a precipitant to precipitate the rubber-filler mixture while simultaneously distilling off the rubber solvent. The precipitated rubberfiller mixture is separated from the water and dried with constant agitation. The aqueous emulsion of the rubber solution is stabilized by a special combination of ingredients and the precipitation bath is adjusted to a pH of from 1 to 5 and maintained at a temperature above the azeotropic boiling point of the solvent and water. In addition, the precipitation bath contains sufficient sodium water glass that from 0.001 to 20% by weight, based on the total rubber content, of colloidally dissolved silica is produced therefrom at the pH value of the precipitation bath.