Bioriented polyethylene film with a high water vapor transmission rate

摘要

Polyethylene films having desired water vapor transmission rates (WVTR) and methods of producing the same are provided. The methods include adherently superimposing at least one layer of a WVTR-controlling material to a base layer including a polyethylene and a cavitating agent, and subsequently biaxially orienting the composite polyethylene sheet to yield a film having the desired WVTR. The base layer has a porous microstructure and a WVTR substantially higher than the desired WVTR.