Process for producing polyolefin microporous breathable film

Abstract

Polyolefin/filler breathable films may be produced by machine or transverse direction orientation using interdigitating grooved rollers. Biaxial orientation to similarly produce breathable films may be accomplished by the same method. By heating the rollers, the breathability of the film is increased without increasing the depth of engagement of the interdigitating rollers.

Dependencies are inferred from the claim text.