Continuous removal of residual hydrocarbons from polyolefins

摘要

Polyolefins which are made by subjecting alpha -olefins to catalytic polymerization are freed from residual liquid hydrocarbons by means of steam and water. To this end, the invention provides: (a) for the hydrocarbon-containing polyolefin to be introduced into an aqueous emulsifier-containing emulsion and for the resulting mixture to be stirred so as to be converted to a homogeneous dispersion; (b) for the dispersion to be introduced into the upper portion of a column with at least 5 sieve plates therein and contacted countercurrently with steam of about 100 DEG to 120 DEG C., the individual plates provided in the column having a free cross-sectional area which increases continuously from the lowermost to uppermost plate by about 3% up to 90% of the plate surface area, and being spaced apart from each other at approximately the same ratio from below to above; and (c) for the aqueous polyolefin dispersion free from hydrocarbons to be removed through the base portion of the column and for the polyolefin to be separated from the water.