Process for the purification of solid polyolefins of high molecular weight

Claim 1

A PROCESS FOR REDUCING THE ASH CONTENT OF POLYETHYLENE TO LESS THAN 0.01%, SAID POLYETHYLENE HAVING BEEN PRODUCED BY THE POLYMERIZATION OF ETHYLENE IN A DILUENT AT PRESSURE BELOW APPROXIMATELY 100 KG./CM.2 AND AT TEMPERATURES UP TO APPROXIMATELY 100*C. WITH CATALYSTS CONSISTING OF MIXTURES OF ALUMINUM ALKYL COMPOUNDS WITH TITANIUM COMPOUNDS, WITH COMPRISES SUBSTANTIALLY SEPARATING SAID POLYETHYLENE FROM SAID DILUENT, TREATING IT WITH A SOLVENT MIXTURE CONTAINING FROM ABOUT 0.3 TO ABOUT 0.5 PERCENT OF HYDROGEN CHLORIDE, SAID SOLVENT MIXTURE CONSISTING OF AN ALCOHOL PRESENT IN AN AMOUNT NOT GREATER THAN 30 PARTS AND HAVING A CONCENTRATION ABOVE 95%, AND AT LEAST ABOUT 70 PARTS OF A HYDROCARBON, AT TEMPERATURES BELOW 100*C., SEPARATING SAID POLYETHYLENE THEREFROM, WASHING IT TO NEUTRALITY, AND DRYING IT.