Abstract: Oxidized polyethylenes useful as lubricants in the extrusion of polyvinyl chloride are prepared by oxidation of finely divided polyethylene of high density at elevated temperatures with an oxidation gas of air and/or oxygen, the polyethylene used containing from 0.015 to 0.5% by weight of a free radical former organic compound in admixture and being contacted per hour with an oxidation gas which per kilogram of polyethylene contains from 30 to 600, in particular from 80 to 300, mg of ozone, with or without a reduced pressure treatment at elevated temperatures after the oxidation.

Abstract: Oxidized polyethylenes useful as water-emulsifiable waxes and as lubricants in the extrusion of polyvinyl chloride are prepared by oxidizing finely divided polyethylene of high density at elevated temperatures with an oxidation gas of air and/or oxygen, the oxidation gas supplied per hour containing not less the 100 mg of ozone per kilogram of polyethylene, by performing the oxidiation in a paddle dryer and passing the oxidation gas into the free gas space above the polyethylene, the temperature in the paddly dryer preferably being continuously adjusted to from 1.degree. to 2.degree. C. below the softening point of the polyethylene.