Reducing the dust content of finely divided polyolefins - by forming a suspension heating, separating, washing and drying

Reducing the proportion of particles with dia. below 200 m mu in finely divided polyolefins e.g. polyethylene, comprising particles with dia below 3.5 mm, comprises (1) suspending 1 pbe of the polyolefin, in 2-6 pbw of a water-sol, inert, liq. e.g. ethylene glycol; heating the resulting suspension to 2-6.5 degrees C below the melting range of the polymer, maintaining the suspension at that temp. for 5-30, the processing time being of a duration inversely proportional to the working temp; then (2) separating the so-treated polyolefin from the suspension medium; washing with water; and drying. Step (1) is effected under continuous stirring. The resulting dust-free prod. has improved flow characteristics and is free of voids giving mouldings free of cavities.