Three stage polymerization process for the production of polyvinyl chloride resins

Claim 1

A METHOD FOR THE PRODUCTION OF VINYL RESINS WHICH COMPRISES SUSPENSION-POLYMERIZING A MONOMERIC MATERIAL (A) SELECTED FROM THE GROUP CONSISTING OF VINYL CHLORIDE AND MIXTURES OF VINYL CHLORIDE WITH A MINOR AMOUNT OF A MONOMER COPOLYMERIZABLE THEREWITHIN IN THE AMOUNT OF A MONOMER COPOLYMERIZABLE THEREWITH IN THE PRESENCE OF AN OIL SOLUBLE CATALYST IN A FIRST STAGE, THEN, IN A SECOND STAGE, ADDING AN ALKYL ACRYLATE MONOMER HAVING 4 TO 12 ATOMS IN THE ALKYL GROUP TO THE SUSPENSION POLYMERIZATION MIXTURE WHEN THE POLYMERIZATION YIELD OF SAID SUSPENSION POLYMERIZATION IN THE FIRST STAGE HAS REACHED 50 TO 90% AND, IN A THIRD STAGE, ADDING A FURTHER QUANTITY OF SAID MONOMERIC MATERIAL (A) TO THE SUSPENSION POLYMERIZATION MIXTURE WHEN THE POLYMERIZATION YIELD OF THE MONOMER MIXTURE PERCENT IN THE SECOND STAGE HAS REACHED 50 TO 90% AND, CONTINUING THE POLYMERIZATION, WHEREIN THE FIRST FEEDING OF MONOMERIC MATERIAL (A) IS WITHIN THE RANGE OF 10% TO 50%, BASED ON THE TOTAL COMPOSITION; THE SECOND FEEDING OF CRYLIC ACID ESTER MONOMER IS WITHIN THE RANGE OF 2% TO 30% AND THE THIRD FEEDING OF FURTHER MONOMERIC MATERIAL (A) IS WITHIN THE RANGE OF 88% TO 20%, WHEREBY A GRAFT POLYMER PARTICLE STRUCTURE IS OBTAINED IN WHICH THE PARTICLES OF THE POLYMER OF MONOMERIC MATERIAL (A) PRODUCED IN THE FIRST STAGE ARE PENETRATED AND COPOLYMERIZED WITH THE ALKYL ACRYLATE IN THE SECOND STAGE AND THE MONOMERIC MATERIAL (A) PRODUCED IN THE THIRD STAGE.

Claim 2

A METHOD FOR THE PRODUCTION OF VINYL RESINS WHICH COMPRISES SUSPENSION-POLYMERIZING A MONOMERIC MATERIAL (A) SELECTED FROM THE GROUP CONSISTING OF VINYL CHLORIDE AND MIXTURES OF VINYL CHLORIDE WITH A MINOR AMOUNT OF A MONOMER COPOLYMERIZABLE THEREWITHIN IN THE AMOUNT OF A MONOMER COPOLYMERIZABLE THEREWITH IN THE PRESENCE OF AN OIL SOLUBLE CATALYST IN A FIRST STAGE, THEN, IN A SECOND STAGE, ADDING AN ALKYL ACRYLATE MONOMER HAVING 4 TO 12 ATOMS IN THE ALKYL GROUP TO THE SUSPENSION POLYMERIZATION MIXTURE WHEN THE POLYMERIZATION YIELD OF SAID SUSPENSION POLYMERIZATION IN THE FIRST STAGE HAS REACHED 50 TO 90% AND, IN A THIRD STAGE, ADDING A FURTHER QUANTITY OF SAID MONOMERIC MATERIAL (A) TO THE SUSPENSION POLYMERIZATION MIXTURE WHEN THE POLYMERIZATION YIELD OF THE MONOMER MIXTURE PERCENT IN THE SECOND STAGE HAS REACHED 50 TO 90% AND, CONTINUING THE POLYMERIZATION, WHEREIN THE FIRST FEEDING OF MONOMERIC MATERIAL (A) IS WITHIN THE RANGE OF 10% TO 50%, BASED ON THE TOTAL COMPOSITION; THE SECOND FEEDING OF CRYLIC ACID ESTER MONOMER IS WITHIN THE RANGE OF 2% TO 30% AND THE THIRD FEEDING OF FURTHER MONOMERIC MATERIAL (A) IS WITHIN THE RANGE OF 88% TO 20%, WHEREBY A GRAFT POLYMER PARTICLE STRUCTURE IS OBTAINED IN WHICH THE PARTICLES OF THE POLYMER OF MONOMERIC MATERIAL (A) PRODUCED IN THE FIRST STAGE ARE PENETRATED AND COPOLYMERIZED WITH THE ALKYL ACRYLATE IN THE SECOND STAGE AND THE MONOMERIC MATERIAL (A) PRODUCED IN THE THIRD STAGE.