Patent ID: 9061474
Filing Date: 2015-06-23
Classification: B29D,C08G,C08J,C08K,C08L,C09D

Abstract:
1. A method of preparing a transparent polyimide film, comprising the steps of: copolymerizing an aromatic dianhydride and a diamine to obtain a polyamic acid; casting the polyamic acid on a support to imidize the polyamic acid; and introducing polyphenylsilsesquioxane as an additive for improving tear strength before or after obtaining the polyamic acid, wherein the aromatic dianhydride is at least one selected from the group consisting of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, and biscarboxyphenyl dimethyl silane dianhydride, wherein the aromatic dianhydride necessarily includes the 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride; and the diamine is at least one selected from the group consisting of oxydianiline, p-phenylenediamine, m-phenylenediamine, p-methylenedianiline, m-methylenedianiline, bistrifluoromethyl benzidine, cyclohexane-1,3-diamine, cyclohexane-1,4-diamine, and bisaminohydroxy phenyl hexafluoropropane, wherein the aromatic diamine necessarily includes the bistrifluoromethyl benzidine.