PROCESS FOR POLYMERISING OLEFIN IN GAS PHASE.

摘要

THE PRESENT INVENTION RELATES TO A PROCESS FOR CONTINUOUSLY MANUFACTURING ETHYLENE (CO-)POLYMER IN A GASEOUS PHASE IN A POLYMERIZATION ZONE THROUGH WHICH PASSES AN ESSENTIALLY GASEOUS REACTION MIXTURE COMPRISING THE (CO-)MONOMERS(S). IN ADDITION THE PROCESS COMPRISES TRANSFERRING A MIXTURE (A) FORMED BY THE GASEOUS REACTION MIXTURE AND THE SOLID (CO-)POLYMER IN A DEPRESSURIZATION ZONE, AND SEPARATING THE MIXTURE (A) INTO A SOLID PHASE (B) AND A GASEOUS PHASE (C) RETURNED INTO THE POLYMERIZATION ZONE. THE SOLID PHASE (B) IS SUBJECTED TO (1) AT LEAST ONE NON-DEACTIVATING FLUSHING WITH RESPECT TO THE ACTIVE CATALYTIC RESIDUES, AND SUBSEQUENTLY (2) A DEACTIVATING FLUSHING WITH A GASEOUS MIXTURE OF NITROGEN, WATER AND OXYGEN. THE (CO-)POLYMER THUS OBTAINED HAS VERY LOW CONTENTS OF UNREACTED (CO-) MONOMER (S) AND VOLATILE ORGANIC COMPOUNDS, AND EXHIBITS A HIGH WHITENESS INDEX AND A LONG THERMAL STABILITY WITH TIME.