Suspension copolymerization of vinyl esters and unsaturated aliphatic acids

Claim 1

IN THE PROCESS OF MAKING A COPOLYMER OF A VINYL ESTER SELECTED FROM THE GROUP CONSISTING OF VINYL ACETATE, VINYL PROPIONATE, VINYL BUTYRATE AND VINYL STEARATE WITH A WATER SOLUBLE ETHYLENIC BOND COPOLYMERIZABLE ALIPHATIC ACID SELECTED FROM THE GROUP CONSISTING OF CROTONIC, FUMARIC, MALEIC AND METHACONIC ACIDS, THE IMPROVEMENT WHICH COMPRISES FORMING A SUSPENSION OF FINE PARTICLES OF THE VINYL ESTER AND AN ORGANIC PEROXIDE POLYMERIZATION INITIATOR DISSOLVED IN THE SAID ESTER IN AN AQUEOUS SOLUTION OF THE SAID ACID, POLYVINYL ALCOHOL, AND HYDROGEN PEROXIDE AS THE INITIATOR, WARMING THE SAID SUSPENSION TO AT LEAST 75*C. UNTIL POLYMERIZATION OF THE SAID ESTER AND ACID IS EFFECTED AND THEN SEPARATING THE RESULTING COPOLYMER BEADS FROM THE REMAINING AQUEOUS PHASE, APPROXIMATELY 75% OF THE POLYVINYL ALCOHOL BEING ADMIXED IN ADVANCE OF SAID WARMING OF THE SUSPENSION AND THE REMAINDER BEING INTRODUCED WHEN THE TEMPERATURE HAS BEEN RAISED TO APPROXIMATELY 75*C. AND THE PROPORTIONS USED BEING 0.01-0.3 MOLE OF SAID POLYMERIZABLE ACID FOR EACH MOLE OF SAID ESTER, AND FOR 100 PARTS BY WEIGHT OF THE VINYL ESTER, 30-500 PARTS OF WATER, 0.01-1 PART OF THE HYDROGEN PEROXIDE ON THE ANHYDROUS BASIS, 0.1-3 PARTS OF THE ORGANIC PEROXIDE INITIATOR, AND 0.05-10 PARTS OF THE POLYVINYL ALCOHOL.