Melt-fusible co-polyimide from diamine mixture

Claim 1

A melt-fusible copolyimide consisting essentially of two types of repeating units ##STR5## where Q is at least one divalent organic radical represented by the following formula (3): ##STR6## where G is selected from the group consisting of isopropylidene, O, S, CH 2 , SO 2 , and CO; and n is 0 or 1; the terminal bonds being in a position other than the ortho position to any other covalent bond; and X is at least one divalent organic radical represented by the following formula (4): ##STR7## where G' is selected from the group consisting of O, S, SO 2 , and CO; each of m, p, and q individually is 0 or 1; but, when any one of m, p, and q is other than 0, then at least two of m, p, and q are 1: Z is hydrogen, phenyl, or one of ##STR8## but when m=p=q=zero, Z is other than hydrogen and is in a position other than in the ortho position with respect to both terminal bonds, and the two terminal bonds are in positions other than ortho to each other; further provided that any aromatic ring other than the aromatic rings carrying the pendant covalent bonds are substituted or may be substituted by cholorine, so long as the number of chlorine atoms in the molecule does not exceed 4, and the maximum number of chlorine atoms per aromatic ring is 2; the mole proportion, t, of the repeating units of the type represented by formula (1) being about 10-90%, and the mole proportion, u, of the repeating units represented by formula (2) being about 90-10%, the minimum value of u being such that u=100-10(m+p)-15(q+n)-0.3(z-l) mole %, where z is the formula weight of Z; u always being calculated for X having the smallest formula weight.