Patent ID: 6740184
Filing Date: 2004-05-25
Classification: B29C,B32B

Abstract:
A high speed method of making a thermoplastic film comprisingmelting a thermoplastic composition, extruding a web of said molten thermoplastic composition from a slot die through a cooling zone into a nip of rollers to form a film at a speed on the order of at least about 500 fpm to about 1200 fpm, employing a first and a second cooling device which are offset on opposite sides of said web between said slot die and said nip of rollers, each said cooling device for directing a stream of cooling gas to flow through said zone substantially parallel to the surface of said web to cool the web and form a film without draw resonance, and each said cooling device for enhancing the cooling effectiveness of said cooling gas by creating a plurality of vortices of said gas as the stream moves through said zone to cool the web.