Patent ID: 6033514
Filing Date: 2000-03-07
Classification: B29C,B29K,B32B,C08J,C08L

Abstract:
A method of making a multilayer thermoplastic film having improved barrier and haze properties, comprising the steps of:(a) forming a blend of a polypropylene resin selected from the group consisting of isotactic homopolymers of propylene, copolymers of propylene with ethylene or butene, terpolymers of propylene with ethylene and butene and mixtures thereof, and 0.25 to 15 wt. % of a crystalline, incompatible wax having an average molecular weight of 300 to 1000;(b) extruding and casting the blend to form a core layer of a film;(c) orienting the Core layer in biaxial directions; and,(d) then providing on each side of the oriented core layer a polyolefin cap layer to provide a multilayer film, whereby loss of wax from said film is avoided.