US 11,872,740 B2
Microporous breathable film and method of making the microporous breathable film
Jeffrey Alan Middlesworth, Wauconda, IL (US); Brooke D. Kitzmiller, North Canton, OH (US); and Bradley Sonnentag, Boyd, WI (US)
Assigned to BERRY PLASTICS CORPORATION, Evansville, IN (US)
Filed by BERRY PLASTICS CORPORATION, Evansville, IN (US)
Filed on Jul. 8, 2016, as Appl. No. 15/206,072.
Claims priority of provisional application 62/233,128, filed on Sep. 25, 2015.
Claims priority of provisional application 62/191,010, filed on Jul. 10, 2015.
Prior Publication US 2017/0008211 A1, Jan. 12, 2017
This patent is subject to a terminal disclaimer.
Int. Cl. B29C 48/00 (2019.01); B29C 55/18 (2006.01); B29C 48/88 (2019.01); B29C 55/06 (2006.01); B29C 55/08 (2006.01); B29K 23/00 (2006.01); B29K 105/16 (2006.01); B29K 509/00 (2006.01); B29K 105/04 (2006.01); B29C 48/08 (2019.01)
CPC B29C 48/0018 (2019.02) [B29C 48/022 (2019.02); B29C 48/914 (2019.02); B29C 55/18 (2013.01); B29C 48/08 (2019.02); B29C 48/917 (2019.02); B29C 55/06 (2013.01); B29C 55/08 (2013.01); B29K 2023/06 (2013.01); B29K 2023/12 (2013.01); B29K 2105/04 (2013.01); B29K 2105/041 (2013.01); B29K 2105/16 (2013.01); B29K 2509/00 (2013.01)] 31 Claims
OG exemplary drawing
 
1. A process for making a multi-layer breathable barrier film comprising the steps of
co-extruding at least a first composition comprising a polyolefin and an inorganic filler and a second composition comprising a hygroscopic polymer to form a multi-layer molten web, the multi-layer molten web comprising a microporous breathable film layer and a moisture-permeable barrier layer,
casting the molten web against a surface of a chill roll using a vacuum box, or a combination of a vacuum box and one or both of an air knife and an air blanket, and without use of a nip, to form a quenched film, wherein the molten web is configured to hit the surface of the chill roll within a distance of less than about 3 inches, and
stretching the quenched film to form the multi-layer breathable barrier film, wherein the stretching comprises cross-directional intermeshing gear (CD-IMG) stretching and machine direction (MD) stretching, and wherein at least a portion of the stretching is performed at a temperature of between about 60 degrees Fahrenheit and about 200 degrees Fahrenheit;
wherein the process for making the multi-layer breathable barrier film does not include MD-IMG stretching, and wherein the MD stretching occurs after the CD-IMG stretching; and
wherein the microporous breathable film layer made by the process has a basis weight of less than about 10 gsm, a Dart Impact Strength of greater than about 90 grams, and a strain at peak machine direction of at least about 125%.