Copolymers preparation process

Claim 1

IN A PROCESS FOR PREPARING A HALOGENATED COPOLYMER OF ETHYLENE AND A HIGHER ALPHA OLEFIN COMPRISING HALOGENATING A COPOLYMER OF ETHYLENE AND OROPOYLENE IN THE PRESENCE OF AN IRON-CONTAINING MATERIAL WITH A HALOGENATING AGENT SELECTED FROM THE GROUP CONSISTING OF CHLORINE, BROMINE, IODINE, FLUORINE, DICHLORO DIMETHYLHYDANTOIN AND N-BROMO-SUCCINIMIDE AT A TEMPERATURE OF 0*C. TO 150*C. IN AN INERT HYDROCARBON DILUENT AT A PRESSURE OF FROM ATMOSPHERIC TO 25 ATMOSPHERES; THE COPOLYMER OF ETHYLENE AND PROPYLENE HAVING BEEN PREPARED FROM 40 TO 60 MOLE PERCENT ETHYLENE AND FROM 60 TO 40 MOLE PERCENT PROPYLENE IN CONTACT WITH THE LOW PRESSURE POLYMERIZATION CATALYST COMPRISING A MIXTURE OF A REDUCING METAL CONTAINING MATERIAL AND A REDUCIBLE HEAVY TRANSITION METAL COMPOUND, THE IMPROVEMENT OF PREVENTING PRODUCT DEGRADATION COMPRISING ADDING FROM 0.1:6G./1. OF POLYMER SOLUTION OF TRIETHYL PHORPHATE TO THE COPOLYMER DISSOLVED IN AN INERT HYDROCARBON DILUENT PRIOR TO THE HALOGENATION REACTION.