Polymerization process

Claim 1

IN A CONTINUOUS PROCESS FOR THE PRODUCTION OF POLYETHYLENE TEREPHTHALATE COMPRISING THE STEPS OF CONTINUOUSLY FEEDING A LOWER DIALKYL ESTER OF TEREPHTHALIC ACID AND ETHYLENE GLYCOL INTO AN ESTER-INTERCHANGE COLUMN WHEREIN SAID ESTER AND GLYCOL ARE CAUSED TO REACT TO FORM BIS-2HYDROXY ETHYL TEREPHTHALATE, CONTINUOUSLY PASSING SAID BIS-2-HYDROXY ETHYL TEREPHTHALATE, AS IT IS FORMED, IN A CONTINUOUS STREAM TO A SUBSTANTIALLY CONSTANT HOLD-UP VESSEL WHEREIN SAID BIS-2-HYDROXY ETHYL TEREPHTHALATE IS CONTINUOUSLY PREPOLYMERIZED TO FORM LOW MOLECULAR WEIGHT POLYETHYLENE TEREPHTHALATE, CONTINUOUSLY PASSING SAID POLYETHYLENE TEREPHTHALATE, FROM SAID VESSEL IN A CONTINOUS STREAM TO A FINAL POLYMERIZATION VESSEL WHEREIN SAID POLYETHYLENE TEREPHTHALATE IS CONTINUOUSLY POLYMERIZED TO FORM A HIGHER MOLECULAR WEIGHT POLYETHYLENE TEREPHTHALATE, AND CONTINUOUSLY REMOVING SAID HIGHER MOLECULAR WEIGHT POLYETHYLENE TEREPHTHALATE IN A CONTINUOUS STREAM FROM SAID FINAL POLYMERIZATION VESSEL, THE IMPROVEMENT WHICH COMPRISES CONTINUOUSLY DISSOLVING IN THE CONTINUOUS STREAM OF BIS-2-HYDROXY ETHYL TEREPHTHALATE, PRIOR TO PREPOLYMERIZING, SOLID PARTICLES OF POLYETHYLENE TEREPHTHALATE, AND AT A RATE CONSTANTLY REGULATED IN RESPONSE TO VARIATION FROM A PREDETERMINED LEVEL OF THE POLYMERIZING MASS IN THE FINAL POLYMERIZATION VESSEL TO MAINTAIN THE LEVEL OF THE POLYMERIZING MASS IN THE FINAL POLYMERIZATION VESSEL SUBSTANTIALLY CONSTANT.