GB825819A - Improvements in rubber compounding - Google Patents

Abstract

In making a rubber-carbon black composition by coagulation of a mixture of a dispersion of carbon black and a natural or synthetic rubber latex, the procedure involving feeding the carbon black and water in predetermined proportions to a mixing chamber, subjecting the mixture to violent agitation in the chamber and forming there a stream of uniform carbon black slurry, mixing a stream of the rubber latex in predetermined proportion with the stream of slurry under violent agitation, and coagulating the mixture, the carbon black employed is "virgin" carbon black, i.e. a carbon black in flocculent form as produced, having been submitted to no densing operation other than mild agitation to effect partial degasifying. The "virgin" carbon black may be of bulk density 3-6 lb/cubic foot. An example is concerned with producing carbon black from a highly aromatic liquid petroleum residue, mixing it with 11 parts of water, mixing the resulting slurry with a dispersion of a low-temperature polymer of butadiene and styrene in the proportion 50 parts of carbon black to 100 parts of rubber, coagulating the slurry-rubber dispersion, washing and drying the resulting crumb, compounding the crumb with zinc oxide, stearic acid, asphaltic flux plasticizer, sulphur, diphenylamine-acetone reaction product, benzothiazyl disulphide and diphenylguanidine, and shaping and vulcanizing the compound. Specifications 705,344 and 765,486, [Group V], are referred to.