Patent ID: 6706228
Filing Date: 2004-03-16
Classification: B29C,B29K

Abstract:
A process for adjusting the WVTR of a breathable filled film manufactured using interdigitating grooved rollers, the process comprising:a) extruding a precursor film including: (i) a polyolefin resin having at least about 20% polypropylene by wt. % of the polyolefin resin, and (ii) a filler in the range of from about 20 to about 70 wt. % of the precursor film; b) heating at least one pair of interdigitating grooved rollers to a predetermined temperature in the range of from about 95Â° F. to about 140Â° F., the predetermined temperature of the rollers being determined by a desired WVTR for the breathable film; c) passing the precursor film between the interdigitating grooved rollers to heat and stretch the precursor film to produce the breathable film, having a WVTR greater than about 1000 g/m2/day at 38Â° C. and 90% relative humidity and having permanent elongation in a stretched direction.