Treatment of vulcanized rubber

Abstract

The invention provides finely divided vulcanized rubber having a particle size of generally less than 20 microns for re-use in the rubber industry. Vulcanizates produced from compositions containing the finely divided vulcanized rubber, either as the sole rubber component or in admixture with unvulcanized rubber, have properties significantly better than those of vulcanizates of similar compositions containing conventional reclaimed rubbers. Vulcanized rubber is converted into the finely divided rubber by the steps of (1) contacting vulcanized rubber with a fatty acid, (2) contacting the product of step (1) with a solid alkali and (3) forming a dispersion of the product of step (2) with a liquid which dissolves the alkali but does not affect the rubber. Alternatively, the finely divided vulcanized rubber results from the steps of (1) contacting the vulcanized rubber with a liquid effective to swell the rubber and thereby weaken it e.g. tetrahydrofuran, (2) comminuting the weakened material and (3) removing the liquid from the comminuted material.

Dependencies are inferred from the claim text.