Molding grade copolymers and process for preparing the same

Claim 1

A PROCESS FOR PREPARING THERMOPLASSTIC COPOLYMERS OF MOLDING GRADE COMPRISING, AS CONTINUOUS STEPS (1) THE PREPARATION OF A HOMOGENEOUS MONOMERIC MATERIAL CONSISTING ESSENTIALLY OF A MONOVINYL AROMATIC MONOMER OF THE BENZENE SERIES AND FROM 1 TO 30 PERCENT BY WEIGHT OF SAID MONOMERIC MATERIAL OF AN UNSATURATED CARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF ACRYLIC AND METHACRYLIC ACIDS, (2) THE EXPOSURE IN A POLYMERIZATION 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 WEIGHT OF SAID MIXTURE, (3) THE MAINTENANCE OF THE PROPORTIONS OF SAID MONOMERIC MATERIAL AND SAID COPOLYMER PRODUCT IN SAID MIXTURE SUBSTANTIALLY CONSTANT BY FEEDING 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.