Powdered rubber

Claim 1

A process for the production of free flowing rubber particles which comprises the coagulation of a latex of a rubber in the presence of a minor proportion of a terpolymer latex, said minor proportion being from about 1 to about 5 parts by weight of dry terpolymer per 100 parts by weight of dry rubber, heating the coagulated mixture so produced to about 190° to about 210° F. while being maintained under mild agitation, and adding to said heated coagulated mixture to encapsulate the rubber particles therein, a latex of said terpolymer in an amount of from about 5 to about 15 parts by weight of dry terpolymer per 100 parts by weight of dry rubber, separating the encapsulated rubber particles from the aqueous phase and drying the separated encapsulated rubber particles to yield free flowing rubber particles, said rubber being a copolymer of about 50 to about 80 weight percent of a C 4 -C 6 conjugated diolefin and about 20 to about 50 weight percent of a C 3 -C 5 vinyl compound containing a nitrile group, said coagulation being in the presence of from 0.1 to 1.0 weight percent of an inorganic salt in water at a temperature of from about 140° to about 180° F. while being subjected to high speed, high shear agitation, characterized in that said terpolymer contains from about 40 to about 60 weight percent of a C 4 -C 6 conjugated diolefin, from about 10 to about 20 weight percent of a C 3 -C 5 vinyl compound containing a nitrile group and from about 30 to about 40 weight percent of a C 8 -C 10 vinyl-or vinylidene-substituted aromatic hydrocarbon and that said terpolymer has rubbery and resinous phases.