Patent ID: 7220478

Claim:
A method for forming an elastic, breathable film comprising the steps of; a) filling a semi-crystalline, predominantly linear polymer with a filler to form a filled polymer such that said filled polymer contains at least 60 percent by weight filler; b) dry-blending a thermoplastic elastomer with said filled polymer to form a blended elastomer composition, such that said blended elastomer composition includes between about 25 and 70 percent filler by weight, between about 5 and 30 percent semi-crystalline polymer by weight, and between about 15 and 60 percent by weight elastomer; c) extruding the blended elastomer composition into a film, wherein said filler is not fully compounded throughout said blended elastomer composition; d) orienting said film in a machine direction from about 2 to about 5 times its original length, such that said film produced has a basis weight of between about 15 and 60 gsm and demonstrates a breathability greater than about 100 g/m 2 /24 hours and a load loss value of less than about 50 percent, at 50 percent elongation, when stretched to 70 percent elongation.