Patent ID: 8367778

Claim:
A process for the elimination of residual mercaptans from a nitrile rubber comprising one or more butadiene-acrylonitrile copolymers having a content of polymerized nitrile monomer units of from 19 to 45% by weight based on the weight of the butadiene-acrylonitrile copolymers, comprising: a. adding a colloidal emulsion of sulfur to a nitrile latex emulsion containing free mercaptan and having a pH of between 7 and 14, at a temperature ranging from 30 to 120° C.; b. coagulating the nitrile latex; and c. washing with demineralized water and drying the nitrile rubber recovered after coagulation, and wherein the butadiene-acrylonitrile copolymers consist of polymerized nitrile monomer units and polymerized butadiene monomer units.