Patent ID: 8426548

Claim:
A polyimide film produced by imidizing a polyamic acid prepared by reacting an aromatic diamine and an aromatic dianhydride, the polyimide film being prepared from a polyimide polymer comprising a block component derived from a thermoplastic polyimide and wherein the ultimately obtained polyimide film is non-thermoplastic, the polyimide film satisfying all the conditions (i) to (iv): (i) an inflection point of a storage modulus of the polyimide film is in a range of 270 to 340° C.; (ii) a peak top of tan δis in a range of 320 to 410° C., where tan δis a value obtained by dividing a loss modulus by the storage modulus; (iii) the storage modulus at 380° C. is in a range of 0.4 to 2.0GPa; and (iv) the storage modulus α1 (GPa) at the inflection point and the storage modulus α2 (GPa) at 380° C. is in a range of the following Equation (1): 85≧{(α1-α2)/α1}×100 ≧65 (1), wherein measurement for the storage modulus, the inflection point of the storage modulus, the peak top of tan δ, and the storage modulus at 380° C. is done at 5Hz.