US 12,251,908 B2
Controlled density thermoplastic multilayer films
Steven Sargeant, Elizabethtown, KY (US); David Ortiz-Grob, Elizabethtown, KY (US); and Dakota Goodman, Eastview, KY (US)
Assigned to FLEX FILMS (USA) INC., Elizabethtown, KY (US)
Appl. No. 17/632,902
Filed by FLEX FILMS (USA) INC., Elizabethtown, KY (US)
PCT Filed Aug. 5, 2020, PCT No. PCT/US2020/044959
§ 371(c)(1), (2) Date Feb. 4, 2022,
PCT Pub. No. WO2021/026204, PCT Pub. Date Feb. 11, 2021.
Claims priority of provisional application 62/882,821, filed on Aug. 5, 2019.
Prior Publication US 2022/0266576 A1, Aug. 25, 2022
Int. Cl. B32B 27/08 (2006.01); B32B 27/20 (2006.01); B32B 27/32 (2006.01); B32B 27/36 (2006.01)
CPC B32B 27/08 (2013.01) [B32B 27/205 (2013.01); B32B 27/325 (2013.01); B32B 27/36 (2013.01); B32B 2250/05 (2013.01); B32B 2250/24 (2013.01); B32B 2307/518 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A biaxially oriented multilayer film comprising:
a stack (A-B)n of n layer units A-B, where n is greater than or equal to 32, each layer unit A-B having individual layers comprising a first layer A and a second layer B overlying the first layer A; and
intralayer voids within a portion of the individual layers in the stack, the intralayer voids having width-to-height aspect ratios from 20:1 to 500:1, wherein:
the first layers of the layer units have a first composition, the first composition comprising a first thermoplastic and a first polymer immiscible with the first thermoplastic; and the second layers of the layer units having a second composition, the second composition comprising a second thermoplastic; and
the second thermoplastic is the same as or different from the first thermoplastic, wherein the biaxially oriented multilayer film has a bulk haze of less than 20, as measured by ASTM D1003.