Process for copolymerizing acrylic compounds

Claim 1

IN A PROCESS FOR COPOLYMERIZING A MONOMER MIXTURE OF ACRYLONITRILE, AT LEAST ONE MEMBER OF THE GROUP CONSISTING OF THE ESTERS OF ACRYLIC AND METHACRYLIC ACIDS WITH THE LOWER SATURATED ALIPHATIC ALCOHOLS, AND A TOTAL OF ABOUT 0 TO 15% BY WEIGHT OF THE MONOMER MIXTURE OF MEMBERS OF THE GROUP CONSISTING OF THE AMIDES OF ACRYLIC AN METHACRYLIC ACIDS, IN WHICH MONOMER MIXTURE THE TOTAL OF ACRYLONITRILE AND AMIDES OF ACRYLIC AND METHACRYLIC ACIDS AMOUNTS TO MORE THAN 50%, THE TOTAL ESTER FROM SAID GROUP OF ESTERS OF ACRYLIC AND METHACRYLIC ACIDS AMOUNTS TO LESS THAN 50% TO ABOUT 5% BY WEIGHT OF THE MONOMER MIXTURE AND THE RATIO BY WEIGHT OF ACRYLONITRILE TO TOTAL AMIDE IS GREATER THAN 5/1, THE MONOMERS OF SAID MIXTURE BEING COPOLYMERIZED IN A REACTION MIXTURE IN WHICH THE MONOMER MIXTURE IS DISPERSED IN AN AQUEOUS MEDIUM CONTAINING A BISULFITE AND A PERSULFATE FROM THE GROUP CONSISTING OF THE ALKALI METAL AND AMMONIUM PERSULFATES TO PROMOTE THE POLYMERIZATION OF THE MONOMERS, THAT IMPROVEMENT WHICH COMPRISES COPOLYMERIZING SAID MONOMERS IN THE PRESENCE IN SAID AQUEOUS MEDIUM OF ABOVE 1% S2O8 AND NOT MORE THAN 9% S2O8 AS SAID PERSULFATE, ABOUT 0.5% AND NOT MORE THAN ABOUT 5% HSO3 AS A BISULFITE OF THE GROUP CONSISTING OF THE BISULFITES OF MAGNESIUM, CLACIUM, ZINC, STRONTIUM AND CADMIUM, SAID PERCENTAGES BEING BASED ON THE WEIGHT OF THE MONOMER PRESENT, AND AT LEAST 0.01 AND NOT MORE THAN 0.6 WEIGHT PART OF FERROUS IRON FROM EVERY 100 WEIGHT PARTS OF HSO3 PRESENT, SUBSTANTIALLY ALL OF SAID IRON BEING PRESENT IN THE AQUEOUS MEDIUM AS FERROUS IRON WHEN THE POLYMERIZATION IS INITATED.