LOW-COLOR POLYMERS FOR USE IN ELECTRONIC DEVICES
Disclosed is a polyimide film that exhibits: an in-plane coefficient of thermal expansion (CTE) that is less than 75 ppm/° C. between 50° C. and 250° C.; a glass transition temperature (T g ) that is greater than 250° C. for the polyimide film cured at 260° C. in air; a 1% TGA weight loss temperature that is greater than 450° C.; a tensile modulus that is between 1.5 GPa and 5.0 GPa; an elongation to break that is greater than 20%; an optical retardation at 550 nm that is less than 100 nm for a 10-μm film; a birefringence at 633 nm that is less than 0.002; a haze that is less than 1.0%; a b* that is less than 3; a yellowness index that is less than 5; and an average transmittance between 380 nm and 780 nm that is greater than 88%.
1 . A polyimide film, wherein the polyimide film exhibits:
an in-plane coefficient of thermal expansion (CTE) that is less than 75 ppm/° C. between 50° C. and 250° C.;
a glass transition temperature (T g ) that is greater than 250° C. for the polyimide film cured at 260° C. in air;
a 1% TGA weight loss temperature that is greater than 450° C.;
a tensile modulus that is between 1.5 GPa and 5.0 GPa;
an elongation to break that is greater than 20%;
an optical retardation at 550 nm that is less than 100 nm for a 10-μm film;
a birefringence at 633 nm that is less than 0.002;
a haze that is less than 1.0%;
a b* that is less than 3;
a yellowness index that is less than 5; and
an average transmittance between 380 nm and 780 nm that is greater than 88%,
wherein the polyimide film is prepared from a solution composition comprising a polyamic acid comprising 4,4′-oxydiphthalic anhydride (ODPA) and 4,4′-[1,4-phenylenebis(1-methyl-ethylidene)] bisaniline (Bis-P).
2 . The polyimide film of claim 1 , wherein the solution composition comprises 4,4′-oxydiphthalic anhydride (ODPA), 4,4′-[1,4-phenylenebis(1-methyl-ethylidene)] bisaniline (Bis-P) and 2,2′-bis(trifluoromethyl) benzidine (TFMB).
3 . The polyimide film of claim 2 , wherein the mole % of ODPA//Bis-P//TFMB is 100/90/10.
4 . The polyimide film of claim 1 , wherein the polyimide film exhibits an optical retardation at 550 nm that is less than 20 nm for a 10-μm film.
5 . A flexible replacement for glass in an electronic device wherein the flexible replacement for glass comprises a polyimide film according to claim 1 .
6 . An electronic device comprising the flexible replacement for glass according to claim 5 .
7 . The electronic device of claim 6 wherein the flexible replacement for glass is used in device components selected from the group consisting of device substrate, touch panel, cover film, and color filter.
8 . A solution composition comprising a polyamic acid in a high boiling aprotic solvent, wherein the polyamic acid comprises 4,4′-oxydiphthalic anhydride (ODPA), and 4,4′-[1,4-phenylenebis(1-methyl-ethylidene)] bisaniline (Bis-P).
9 . A solution composition comprising a polyamic acid in a high boiling aprotic solvent, wherein the polyamic acid comprises 4,4′-oxydiphthalic anhydride (ODPA), 4,4′-[1,4-phenylenebis(1-methyl-ethylidene)] bisaniline (Bis-P) and 2,2′-bis(trifluoromethyl) benzidine (TFMB).
10 . The solution composition of claim 8 , wherein the high-boiling aprotic solvent is N-methyl-2-Pyrrolidone (NMP).