Method of producing vinyl chloridestyrene copolymers

Claim 1

THE METHOD OF PRODUCING A COPOLYMER OF VINYL CHLORIDE AND STYRENE CHARACTERIZED BY FREEDOM FROM CONTAMINATION BY POLYVINYL CHLORIDE AND POYLSTYRENE, BY COMPLETE SOLUBILITY IN ACETONE AND IN ETHYL ACETATE AND BY THE ABILITY TO BE PROCESSED AT TEMPERATURE LOWER THAN THOSE REQUIRED TO PROCESS POLYVINYL CHLORIDE AND POLYSTYRENE, WHICH METHOD COMPRISES PREPARING AN AQUEOUS EMULSION COMPRISING WATER, A WATER-SOLUBLE PERSULFATE, A WATER-SOLUBLE NORMAL ALKALI SULFITE, A DISPERSING AGENT AND MONOMERIC MATERIAL CONSISTING OF MONOMERIC VINYL CHLORIDE AND MONOMERIC STYRENE, SAID WATER BEING PRESENT IN SUFFICIENT AMOUNT TO MAINTAIN THE AQUEOUS PHASE TO MONOMER RATIO IN THE RANGE OF 1:1 TO 6:1, SAID PERSULFATE AND SULFITE BEING PRESENT IN APPROXIMATELY EQUAL AMOUNTS RANGING FROM 0.175 TO 1% EACH BY WEIGHT BASED ON THE TOTAL MONOMERIC MATERIAL, SAID DISPERSING AGENT BEING PRESENT IN AMOUNTS RANGING FROM 0.25 TO 1.25* BASED ON THE TOTAL MONOMERS, AND SAID MONOMERIC STYRENE BEING PRESENT IN AN AMOUNT SELECTED FROM THE RANGE OF FROM 1 TO 10% BY WEIGHT BASED ON THE TOTAL MONOMERIC MATERIAL, STARTING COPOLYMERIZATION OF THE MONOMERIC VINYL CHLORIDE AND STYRENE IN SAID EMULSION AT A TEMPERATURE IN THE RANGE OF 20 TO 70* C. AND AT AUTOGENOUS PRESSURE, ADDING MONOMERIC STYRENE TO SAID EMULSION AS COPOLYMERIZATION PROCEEDS AT A RATE ADAPTED TO MAINTAIN ITS CONCENTRATION IN THE EMULSION AT THE SAID SELECTED AMOUNT IN THE RANGE OF 1 TO 10% BASED ON THE TOTAL MONOMERIC MATERIAL, WHILE CONTINUING COPOLYMERIZATION AND ADDITION OF MONOMERIC STYRENE AT THE SAID TEMPERATURE AND PRESSURE FOR A TIME SUFFICIENT TO CONVERT AT LEAST 40% OF THE TOTAL MONOMERIC MATERIAL TO COPOLYMER, AND FINALLY RECOVERING THE VINYL CHLORIDE STYRENE COPOLYMER FORMED.

Claim 2

THE METHOD OF PRODUCING A COPOLYMER OF VINYL CHLORIDE AND STYRENE CHARACTERIZED BY FREEDOM FROM CONTAMINATION BY POLYVINYL CHLORIDE AND POYLSTYRENE, BY COMPLETE SOLUBILITY IN ACETONE AND IN ETHYL ACETATE AND BY THE ABILITY TO BE PROCESSED AT TEMPERATURE LOWER THAN THOSE REQUIRED TO PROCESS POLYVINYL CHLORIDE AND POLYSTYRENE, WHICH METHOD COMPRISES PREPARING AN AQUEOUS EMULSION COMPRISING WATER, A WATER-SOLUBLE PERSULFATE, A WATER-SOLUBLE NORMAL ALKALI SULFITE, A DISPERSING AGENT AND MONOMERIC MATERIAL CONSISTING OF MONOMERIC VINYL CHLORIDE AND MONOMERIC STYRENE, SAID WATER BEING PRESENT IN SUFFICIENT AMOUNT TO MAINTAIN THE AQUEOUS PHASE TO MONOMER RATIO IN THE RANGE OF 1:1 TO 6:1, SAID PERSULFATE AND SULFITE BEING PRESENT IN APPROXIMATELY EQUAL AMOUNTS RANGING FROM 0.175 TO 1% EACH BY WEIGHT BASED ON THE TOTAL MONOMERIC MATERIAL, SAID DISPERSING AGENT BEING PRESENT IN AMOUNTS RANGING FROM 0.25 TO 1.25* BASED ON THE TOTAL MONOMERS, AND SAID MONOMERIC STYRENE BEING PRESENT IN AN AMOUNT SELECTED FROM THE RANGE OF FROM 1 TO 10% BY WEIGHT BASED ON THE TOTAL MONOMERIC MATERIAL, STARTING COPOLYMERIZATION OF THE MONOMERIC VINYL CHLORIDE AND STYRENE IN SAID EMULSION AT A TEMPERATURE IN THE RANGE OF 20 TO 70* C. AND AT AUTOGENOUS PRESSURE, ADDING MONOMERIC STYRENE TO SAID EMULSION AS COPOLYMERIZATION PROCEEDS AT A RATE ADAPTED TO MAINTAIN ITS CONCENTRATION IN THE EMULSION AT THE SAID SELECTED AMOUNT IN THE RANGE OF 1 TO 10% BASED ON THE TOTAL MONOMERIC MATERIAL, WHILE CONTINUING COPOLYMERIZATION AND ADDITION OF MONOMERIC STYRENE AT THE SAID TEMPERATURE AND PRESSURE FOR A TIME SUFFICIENT TO CONVERT AT LEAST 40% OF THE TOTAL MONOMERIC MATERIAL TO COPOLYMER, AND FINALLY RECOVERING THE VINYL CHLORIDE STYRENE COPOLYMER FORMED.