High speed method of making plastic film and nonwoven laminates
AssigneeClopay Plastic Products Company, Inc.
InventorsRobert M. Mortellite, Thomas G. Mushaben, Pai-Chuan Wu
Life of this patent
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Abstract
Laminates of thermoplastic films and nonwoven fibrous webs are made at high speeds on the order of about 700 fpm to about 1200 fpm. Bond strengths of film and nonwoven laminates are effectively controlled to make breathable laminates at high speeds. Air cooling devices cause the air to flow substantially parallel to the extruded plastic web during drawdown and provide a plurality of cooling air vortices to effectively cool the web. Film gauge control is also achieved by the method.
Claims27
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, 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.
A high speed method of making a laminate of a microporous thermoplastic film and nonwoven fibrous sheet comprising
- melt blending a composition of
- (a) about 30% to about 45% by weight of a linear low density polyethylene,
- (b) about 1% to about 10% by weight of a low density polyethylene,
- (c) about 40% to about 60% by weight calcium carbonate filler particles,
- extruding a web of said melt blended composition and a nonwoven fibrous sheet through a cooling zone into a nip of rollers to form a film at a speed on the order of at least about 700 fpm to about 1200 fpm,
- 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 form a laminated sheet having a bond strength between the film and the fibrous sheet of about 200 to about 500 grams/inch at about room temperature.
- applying an incremental stretching force to said laminated sheet at said speed along lines substantially and uniformly across said laminated sheet and throughout its depth to provide a microporous laminate having a fibrous sheet to film bond strength of about 100 to about 200 grams/inch.
Dependencies are inferred from the claim text.