| abstract |
A composite film having excellent heat resistance. The film is obtained by applying a solution of a solvent-soluble polyimide having a backbone formed by the polycondensation of one or more tetracarboxylic dianhydrides with one or more diamines to at least one surface of a base film and drying the solution to form a polyimide film on the surface. The backbone of the solvent-soluble polyimide comprises units of bicyclo(2,2,2)oct-7-ene-2,3,5,6-tetracarboxylic dianhydride as at least part of the tetracarboxylic dianhydrides and/or units of at least either of 3,5-diaminobenzoic acid and a diaminosiloxane derivative as at least part of the diamines. |