US 11,655,323 B2
Poly(amide-imide) copolymer film and method for preparing same
Bi Oh Ryu, Daejeon (KR); Soonyong Park, Daejeon (KR); Youngseok Park, Daejeon (KR); Il Hwan Choi, Daejeon (KR); Young Ji Tae, Daejeon (KR); and Kwanyeol Paek, Daejeon (KR)
Assigned to LG CHEM, LTD., Seoul (KR)
Appl. No. 16/636,233
Filed by LG CHEM, LTD., Seoul (KR)
PCT Filed Dec. 7, 2018, PCT No. PCT/KR2018/015472
§ 371(c)(1), (2) Date Feb. 3, 2020,
PCT Pub. No. WO2019/135500, PCT Pub. Date Jul. 11, 2019.
Claims priority of application No. 10-2018-0000881 (KR), filed on Jan. 3, 2018; and application No. 10-2018-0153913 (KR), filed on Dec. 3, 2018.
Prior Publication US 2020/0369816 A1, Nov. 26, 2020
Int. Cl. C08F 283/00 (2006.01); C08J 5/18 (2006.01)
CPC C08F 283/00 (2013.01) [C08J 5/18 (2013.01); C08J 2379/08 (2013.01)] 10 Claims
 
1. An aromatic poly(amide-imide) copolymer film, comprising:
an aromatic poly(amide-imide) copolymer comprising a repeating unit derived from an aromatic diamine monomer, a repeating unit derived from an aromatic dianhydride monomer, and a repeating unit derived from an aromatic dicarbonyl monomer,
wherein the aromatic poly(amide-imide) copolymer includes the repeating unit derived from the aromatic dicarbonyl monomer in an amount of 51 mol % or more based on the total moles of the repeating units derived from the aromatic dianhydride monomer and the aromatic dicarbonyl anomer,
wherein retardation (Rth) in the thickness direction of the film as measured at a wavelength of 550 nm is 3000 nm or more, and a moisture absorption rate of the film according to General Formula 1 is 3.6% r, or less:
Moisture Absorption Rate (%)=(W1−W2)*100/W2  [General Formula 1]
in the General Formula 1, W1 is a weight measured by impregnating the aromatic poly(amide-imide) copolymer film in ultrapure water for 24 hours, and
W2 is a weight measured by drying the aromatic poly(amide-imide) copolymer film after at 150° (I for 30 minutes after the impregnation, and
wherein the repeating unit derived from the aromatic dicarbonyl monomer contains 10 to 60 mol % of 4,4′-biphenyldicarbonyl repeating units, 10 to 50 mol % of isophthaloyl repeating units, and 20 to 70 mol % of terephthaloyl repeating units.