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US 11,931,229 B2Granted
Breathable and microporous thin thermoplastic film
AssigneeBerry Film Products Company, Inc.
InventorsLeopoldo V. Cancio, Frank Eschenbacher, Jerry Ford
Life of this patent
Estimating the term…
Abstract
Breathable, thermoplastic films, laminates, and methods of making films having a basis weight less than or equal to 15 gsm and a water vapor transmission rate of at least about 500 grams H2O/24-hour/m2, wherein the film has a ratio of the MD load at break to the CD load at break of less than about 10, and at least one of a machine-direction notched Elmendorf tear strength of at least about 5 g or a machine-direction notched trapezoidal tear strength of at least about 15 g.
Claims21
A method of making a thermoplastic film product is provided, comprising
- extruding a molten web comprising a thermoplastic polymer from an extruder onto a first chill roller, said first chill roller operating at a peripheral velocity V1 and at a temperature T1, wherein the temperature T1 is from about 80° C. to about 160° C., which is below the melting point of the thermoplastic polymer and which cools said molten web to form a film;
- advancing the film to a first stretching roller which operates at a peripheral velocity V2 which is greater than the peripheral velocity V1, and at a temperature T2;
- advancing the film to a first machine direction orientation section comprising at least one heated roller having a temperature T3 and a second stretching roller;
- and
- stretching the film in the first machine direction orientation section in the machine direction to produce a film having limited machine direction orientation and a ratio of the MD load at break to a CD load at break of less than about 10,
- wherein the first chill roller and the first stretching roller are separated by a distance, wherein the distance is at least about 7.5 cm.
3 more elements
Dependencies are inferred from the claim text.