Polyimide film and electric/electronic equipment bases with the use thereof

Claim 1

A polyimide film having a tensile elastic modulus of 700 kg/mm 2 or less and a coefficient of linear expansion at 100 to 200° C. of 5 to 15 ppm which contains three repeating units A, B and C in its molecule, wherein said repeating unit A is represented by the following general formula (A): wherein R 1 represents a divalent organic group selected from among: (wherein R 4 represents CH 3 —, Cl—, Br—, F—or CH 3 O—); and R represents a divalent organic group represented by the following general formula: (wherein n is an integer of 1 to 3; and X represents a monovalent substituent selected from among a hydrogen atom, a halogen atom, a carboxyl group, a lower alkyl group having 6 or less carbon atoms and a lower alkoxy group having 6 or less carbon atoms), said repeating unit B is represented by the following general formula (B): wherein R 1 is as defined in the general formula (A), and R represents a divalent organic group represented by the following general formula: (wherein Y and Z may be the same or different and each represents a monovalent substituent selected from among a hydrogen atom, a carboxyl group, a lower alkyl group having 6 or less carbon atoms and a lower alkoxy group having 6 or less carbon atoms; and A represents a divalent linking group selected from among —O—, —S—, —CO—, —SO—, SO 2 —, and CH 2 —), said repeating unit C is represented by the following general formula (C): wherein R is defined as in any one of the general formulae (A) and (B); and R 3 represents a tetravalent organic group selected from among: and the ratio of repeating units A+B to repeating units C is from 1:3 to 3:1.