Patent ID: 6951591

Claim:
A high speed method of making a laminate of a nonwoven fibrous sheet and a microporous thermoplastic film comprising melt blending a thermoplastic polymer and filler particles to form a thermoplastic polymer 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 greater than about 700 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 the film without draw resonance, each 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, and introducing a nonwoven fibrous sheet into said nip of rollers and controlling the temperature and compressive force between the fibrous sheet and the film at the nip to bond the surface of the fibrous sheet to the film and to form a laminated sheet having bond strength between the film and the fibrous sheet of about 100 to about 600 grams/inch as measured at room temperature.