US 12,111,687 B2
Base film, preparation method thereof, and cover window and display device comprising same
Sunhwan Kim, Incheon (KR); Jung Hee Ki, Gyeonggi-do (KR); Han Jun Kim, Gyeonggi-do (KR); Dae Seong Oh, Seoul (KR); Jin Woo Lee, Seoul (KR); and Sang Hun Choi, Seoul (KR)
Assigned to SK MICROWORKS CO., LTD., Gyeonggi-do (KR)
Filed by SK microworks Co., Ltd., Gyeonggi-do (KR)
Filed on Jun. 26, 2020, as Appl. No. 16/913,366.
Claims priority of application No. 10-2019-0078286 (KR), filed on Jun. 28, 2019; and application No. 10-2019-0169716 (KR), filed on Dec. 18, 2019.
Prior Publication US 2020/0409413 A1, Dec. 31, 2020
Int. Cl. G06F 1/16 (2006.01); B29C 48/00 (2019.01); B29C 48/91 (2019.01); B29C 55/00 (2006.01); B29C 55/08 (2006.01); C08G 73/14 (2006.01); G02B 1/04 (2006.01); G02B 1/14 (2015.01); B29K 77/00 (2006.01)
CPC G06F 1/1609 (2013.01) [B29C 48/0018 (2019.02); B29C 48/91 (2019.02); B29C 55/005 (2013.01); B29C 55/08 (2013.01); C08G 73/14 (2013.01); G02B 1/04 (2013.01); G02B 1/14 (2015.01); B29K 2077/00 (2013.01); B29K 2995/0018 (2013.01); B29K 2995/0069 (2013.01); C08J 2377/10 (2013.01); C08J 2379/08 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A cover window for a display device, which comprises a base film comprising a polyamide-based polymer and having a moisture permeability of 30 g/m2·day to 300 g/m2·day measured in the thickness direction according to ASTM F 372; and a functional layer,
wherein the polyamide-based polymer is formed by polymerizing a diamine compound, a dicarbonyl compound, and optionally a dianhydride compound, and the molar ratio of the dianhydride compound and the dicarbonyl compound is 0:100 to 25:75,
wherein a thickness of the base film is 20 μm to 150 μm,
wherein a content of a residual solvent in the base film is 1,000 ppm or less,
wherein the base film has a modulus of 6.5 GPa or more,
wherein the base film has a yellow index of 3 or less, a transmittance at 550nm of 88% or more, a haze at 550 nm of 1% or less, and
wherein the IS value represented by the following Equation 1 is 10 to 100:

OG Complex Work Unit Math
wherein, in Equation 1, IM stands for the number of moles of the imide repeat unit when the total number of moles of the imide repeat unit and the amide repeat unit in the film is 100; and RS stands for the content (ppm) of the residual solvent in the film.