Molding grade copolymers and process for preparing the same

Claim 1

A PROCESS FOR PREPARING THERMOPLASTIC COPOLYMER OF MOLDING GRADE COMPRISING AS CONTINUOUS STEPS (1) THE PREPARATION OF A HOMOGENEOUS MONOMERIC MATERIAL COMSISTING OF ESSENTIALLY OF FROM ABOUT 55 TO 97 PERCENT OF WEIGHT OF A MONOVINYL AROMATIC MONOMER OF THE BENZENE SERIES CONTAINING ONLY HYDROGEN SUBSTITUTION ON THE VINYL GROUP AND FROM ABOUT 1 TO 40 PERCENT BY WESIGHT OF SAID MONOMERIC MATERIAL OF ALPHA-METHYLSTYRENE AND FROM ABOUT 2 TO 15 PERCENT BY WEIGHT OF METHACRYCLIC ACID, (2) THE EXPOSURE IN A POLYMERZATION ZONE OF A MIXTURE OF SAID HOMOGENEOUS MONOMERIC MATERIAL AND THE COPOLYMER PRODUCT OF POLYMERIZATION THEREOF IN THE LIQUID STATE TO A POLYMERIZATION TEMPERATURE BETWEEN ABOUT 130*C. AND ABOUT 160*C., THE PROPORTION OF SAID COPOLYMER PRODUCT BEING NOT MORE THAN ABOUT 60 PERCENT BY WEIGH OF SAID MIXTURE, (3) THE MAINTENANCE OF THE PROPORTIONS OF SAID MONOMERIC MATERIAL AND SAID COPOLYMER PRODUCT IN SAID MIXTURE SUBSTANTIALLY CONSTANT BY FEEING ADDITIONAL OF SAID MONOMERIC MATERIAL TO THE MIXTURE WHILE WITHDRAWING SAID MIXTURE OF COPOLYMER PRODUCT AND UNPOLYMERIZED MONOMERS FROM SAID ZONE AT ABOUT THE SAME VOLUMETRIC RATE AT WHICH SAID MONOMERIC MATERIAL IS BEING FED TO SAID MIXTURE, ALL OF SAID STEPS BEING CARRIED OUT IN THE SUBSTANTIAL ABSENCE OF IRON, AND FINALLY (4) ISOLATING SAID COPOLYMER PRODUCT FROM SAID MIXTURE BY VOLATILIZING THE UNPOLYMERIZED COMPONENTS AWAY FROM SAID COPOLYMER PRODUCT.