Process for the polymerization of ethylene

Claim 1

IN A LOW PRESSURE, LOW TEMPERATURE PROCESS FOR THE POLYMERIZATION OF ETHYLENE BY CONTACTIG ETHYLENE AND A CATALYST IN THE PRESENCE OF AN ORGANIC OLSVENT AT A TEMPERATURE OF FROM ABOUT 50*C. TO ABOUT 100*C. AND AT A PRESSURE BELOW 100 ATOMOSPHERES, IN WHCIH THE CATALYST IS A MIXTURE OF (A) AND (B), COMPONENT (A) BEING SELECTED FROM THE GROUP CONSISTING OF ALN ALKYL ALUMINUM, AN ALKYL ALUMINUM CHLORIDE, AND AN ALKYL ALUMINUM HYDRIDE AND COMPONENT (B) BEING SELECTED FROM THE GROUP CONSISTING OF TITANIUM THTRACHLORIDE, TITANIUM OXYCHLOFIDE, AND TITANIUM ACETHYLACETONATE, THE MOLAR RATIO OF COMPONENT (A) TO COMPONENT (B) BEING IN THE RANGE OF 0.5:1 TO 12:1, THE IMPROVEMENT IN SAID LOW PRESSURE, LOW TEMPERATURE POLYMERIZATION PROCESS WHICH COMPRISES CONTINUOUSLY AND SIMULTANEOUSLY ADDING TO A POLYMERIZATION REACTION ZONE ETHYLENE AND A MIXTURE IN AN ORGANIC SOLVENT OF SAID CATALYST COMPONENTS (A) AND (B) IN A MOLAR RATIO OF FROM 0.5:1 TO 12D1, CONTINUOUSLY POLYMERIZING ETHYLENE IN SAID ZONE AT A TEMPERATURE OF FROM ABOUT 50*C. TO ABOUT 85*C., CONTINUOUSLY WITHDRAWING A POLYMER SLURRY FROM SAID ZONE AT A RATE TO MAINTAIN THE QUANTITY OF SUBSTITUENTS IN SAID REACTION ZONE SUBSTANTIALLY CONSTANT, CONTINUOSLY SEPARATING SAID POLYMER SLURRY INTO A SOLID POLYETHYLENE PHASE AND A LIQUID RESIDUE AND RETURNING THE LIQUID RESIDUE TO THE POLYMERIZATION REACTION ZONE.