Abstract: Pulverulent rubber powder containing filler which remains free-flowing even after exposure to mechanical stresses, a process for the production thereof, in which the rubber powder is obtained in two precipitation steps, and the use of these powders for the production of vulcanizable rubber compounds.

Abstract: Finely divided, pulverulent rubbers containing filler which contain further processing and vulcanization auxiliaries necessary for the production of vulcanizable rubber mixtures, which rubbers are pourable even after exposure to mechanical action, and to a process for the production thereof. The rubber powder is obtained within two precipitation steps. These rubber powders are used for the production of vulcanizable rubber mixtures. The fillers used, which comprise not only precipitated silicas but also carbon blacks known in the rubber industry, are optionally surface modified with organosilicon compounds.

Abstract: Finely divided powdered rubbers containing filler which remain free-flowing even after exposure to mechanical stresses and to a process for the production thereof, in which the rubber powder is obtained in two precipitation steps, and to the use of these powders for the production of vulcanizable rubber compounds. The fillers used, which are both precipitated silicas and carbon blacks known in the rubber art, are surface-modifed by organosilicon compounds.

Abstract: The invention relates to a process for the preparation of finely divided rubbers (rubber powders) by precipitation from aqueous mixtures, which comprise filler in the form of suspensions, water-soluble salts of a metal of groups IIa, IIb, IIIa and VIII of the periodic table of the elements arid a rubber latex (polymer latex), aqueous emulsions of a rubber or rubber solution, in which one or more organosilicon compound(s) containing at least one alkoxy group is or are dissolved or emulsified, optionally in the presence of a surface-active substance, in water, or the compounds mentioned are mixed directly, optionally with a surface-active substance, with an aqueous suspension of an oxidic or silicatic finely divided filler or a mixture of these fillers at a temperature of 10 to 60° C., preferably at room temperature, while stirring, the amount of this mixture envisaged for incoporation in the rubber, based on the filler content, in general being divided into two batches.