| 摘要 |
<p>Provided is a process for the production of a transparent polyimide film which comprises using 3,3',4,4'-biphenyl- tetracarboxylic dianhydride and 2,2'-bis(trifluoromethyl)- benzidine as the monomers and which can produce such a film that exhibits a reduced dimensional change under heat. A polyimide film which exhibits excellent dimensional stability under heat can be obtained by: mixing a polyamic acid solution with a chemical imidating agent to prepare a gel film; baking the gel film at high temperature; and then cooling the resulting film while gradually lowering the temperature of the cooling process.</p> |
