| CPC C08J 5/18 (2013.01) [C08G 73/1078 (2013.01); C08J 2379/08 (2013.01)] | 16 Claims |
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1. A polyimide-based film having a Kc value of 1.55 or less,
wherein the polyimide-based film is produced by:
preparing a liquid resin composition using monomer components including dianhydride and diamine,
producing a gel-state film using the liquid resin composition,
first drying the gel-state film at a temperature of 50 to 150° C. at a wind speed of 0 m/s or less for a drying period of 2 to 20 minutes, and
second drying the gel-state film at a wind speed of 1.0 to 5.0 m/s at 70 to 140° C. after the first drying,
wherein the Kc value is a curvature parameter measured for a waviness having a wavelength range of 1.0 to 3.0 mm by phase stepped deflectometry,
wherein a polyimide-based film sample having a width of 15 cm×a length of 15 cm×thickness of 80 μm is used for measuring K, and
a measuring device is in a curvature mode K with 1.0 to 3.0 mm wavelength range, and a sheet of black matte paper is placed on a surface plate in a dark room, the sample to be measured is placed thereon, the Kc value is measured 10 times, and the average value is used as the Kc value of the sample,
wherein the polyimide-based film is produced from monomer components including dianhydride and diamine,
the dianhydride comprises at least one selected from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 3,3′,4,4′-biphenyl tetracarboxylic dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, pyromellitic dianhydride, 3,3′,4,4′-benzophenone tetracarboxylic dianhydride, 4,4′-oxydiphthalic anhydride, 4,4′-(3,4-bisdicarboxyphenoxy-diphenyl sulfide dianhydride, 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride, 4,4′-(4,4′-Isopropylidenediphenoxy)bis(phthalic anhydride), cyclobutane-1,2,3,4-tetracarboxylic dianhydride, 1,2,3,4-cyclopentane-tetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, and dicyclohexyl-3,4,3′,4′-tetracarboxylic dianhydride,
the diamine comprises at least one selected from 3,4-oxydianiline, 4,4′-oxydianiline, p-phenylenediamine, m-phenylenediamine, 4,4-methylenedianiline, 3,3-methylenedianiline, 1,3-Bis(3-aminophenoxy)benzene, 1,3-Bis(4-aminophenoxy)benzene, 2,2′-bis[4-(4-aminophenoxy) phenyl] hexafluoropropane, 2,2′-bis(3-aminophenyl)hexafluoropropane, 2,2′-bis(4-aminophenyl) hexafluoropropane, bis(4-aminophenyl)sulfone, bis(3-aminophenyl)sulfone, 2,2′-bis(trifluoromethyl)benzidine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, bis[4-(4-aminophenoxy)phenyl] sulfone, bis[4-(3-aminophenoxy)phenyl] sulfone, 9,9-bis(4-aminophenyl)fluorene and 9,9-bis(4-amino-3-fluorophenyl)fluorene.
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