Bulk interpolymerization of monomeric mixture comprising acrylonitrile and alpha-alkyl styrene

Claim 1

A MULTISTAGE BULK POLYMERIZATION PROCESS FOR PRODUCTION OF A THERMOPLASTIC POLYMER PRODUCT CONTAINING FROM ABOUT 15 TO 48 PERCENT OF CHEMICALLY COMBINED ACRYLONITRILE AND AT LEAST ONE OTHER CHEMICALLY COMBINED INTERPOLYMERIZABLE MATERIAL, WHICH PROCESS COMPRISES THE STEPS OF: (A) BULK PREPOLYMERIZING A REACTANT MIXTURE, WHICH COMPRISES, FOR EACH 100 PARTS OF THE REACTANT MIXTURE, FROM ABOUT 15 TO 48 PARTS OF ACRYLONITRILE MONOMER, FROM 1 TO 52 PARTS OF AN ALPHA-LOWER ALKYL STYRENE MONOMER IN AT LEAST A MINIMUM AMOUNT THEREOF EFFECTIVE AS A REACTIVE POLYMERIZATION MODERATOR AND FROM 0 TO 84 PARTS OF AT LEAST ONE OTHER POLYMERIZABLE MONOMER INTERPOLYMERIZED THEREWITH, TO A CONVERSION OF ABOUT 30 TO 60 PERCENT POLYMERIC MATERIAL WITH THE BULK PREPOLYMERIZING BEING CONDUCTED WITH AGITATION OF THE REACTANT MIXTURE AT A TEMPERATURE BETWEEN 60* AND 100*C., WITH AN INITIAL CHARGE OF REACTANT MIXTURE CONTAINING ALL OF THE ACRYLONITRILE MONOMER AND FROM 60 TO 80 PERCENT OF THE ALPHA-LOWER ALKYL STYRENE MONOMER AND FROM 60 TO 80 PERCENT OF SAID OTHER POLYMERIZABLE MONOMER, AND WITH THE BALANCE OF THE ALPHA-LOWER ALKYL STYRENE MONOMER AND THE BALANCE OF SAID OTHER POLYMERIZABLE MONOMER ADDED TO THE REACTANT MIXTURE DURING THE BULK PREPOLYMERIZING BEFORE COMPLETION OF THE BULK PREPOLYMERIZING; AND (B) FURTHER BULK POLYMERIZING THE RESULTING PREPOLYMER PRODUCT OF STEP (A) TO A CONVERSION IN EXCESS OF ABOUT 90 PERCENT POLYMERIC MATERIAL IN THE FORM OF A SOLID OF A THICKNESS BETWEEN ABOUT 2 AND 6 INCHES, WITH THE BULK FURTHER POLYMERIZING BEING CONDUCTED WITHOUT AGITATION OF SAID PREPOLYMER AND 100*C. AND 200*C.