Two-stage emulsion polymerization process

Claim 1

A PROCESS FOR PRODUCING RUBBER-LIKE POLYMERS WHICH COMPRISES PREPARING AN EMULSION CONTAINING 100 PARTS OF BUTADIENE-1,3,0.5 TO 5 PARTS OF AN EMULSIFIER, 150 TO 400 PARTS OF AN AQUEOUS MEDIUM WHICH DOES NOT FREEZE AT THE POLYMERIZATION TEMPERATURE, UP TO 5 PARTS OF ACRYLONITRILE, 0.05 TO 0.3 PARTS OF CUMENE HYDROPEROXIDE, AND 0.2 TO 0.6 PART OF A MERCAPTAN OF 6 TO 18 CARBON ATOMS, BRINGING THE EMULSION TO A POLYMERIZATION TEMPERATURE BETWEEN +20 AND -20* C., ADDING TO THE EMULSION AND ACTIVATOR SOLUTION CONTAINING 0.2 TO 0.35 PART OF FERRIC PYROPHOSPHATE, 0.5 TO 1.5 PART OF SODIUM PYROPHOSPHATE DECAHYDRATE AND 1 TO 3 PARTS OF REDUCING SUGAR, MAINTAINING THE RESULTING MIXTURE AT THE POLYMERIZATION TEMPERATURE UNTIL ABOUT 15 TO 30 PERCENT OF THE BUTADIENE CHARGED IS CONVERTED INTO A POLYMER HAVING A MOONEY VISCOSITY BETWEEN 1 AND 50, ADDING TO THE PARTIALLY POLYMERIZED REACTION MIXTURE 15 TO 50 PARTS OF ACRYLONITRILE, CONTINUING THE POLYMERIZATION OF THE RESULTING MIXTURE TO A CONVERSION BETWEEN 65 AND 99%, AND RECOVERING THE RESULTING RUBBER-LIKE POLYMER FROM THE MIXTURE.