Patent ID: 7892466

Claim:
A process for producing a polyethylene film having improved optical properties, comprising: a) providing a mixer/extruder, wherein the mixer/extruder comprises a feed zone, a melt-conveying zone, and an optional melting zone; b) providing a polyethylene to the feed zone of the mixer/extruder, wherein the polyethylene consists essentially of unimodal polyethylene and has a density of from 0.915 g/cm 3 to 0.925 g/cm 3 , and wherein the feed zone and the optional melting zone are substantially free of intentionally added oxygen such that the feed zone and the optional melting zone contain less than 1 volume % of intentionally added oxygen; c) conveying the polyethylene through the mixer/extruder, wherein in the melt-conveying zone the polyethylene is substantially melted; d) contacting the substantially melted polyethylene with a gas mixture comprising 1.0 to 70 volume % oxygen, to produce an oxygen-treated polyethylene, wherein the contacting occurs in the melt-conveying zone; and e) extruding the oxygen-treated polyethylene into a film by a blown film process, wherein the film has a haze as measured by ASTM D 1003 at least 10% lower than a film made from the same polyethylene mixed/extruded under the same conditions except that the polyethylene is mixed/extruded in the substantial absence of oxygen.