Patent ID: 7288603

Claim:
A polybenzazole compound including an aromatic dicarboxylic acid bond unit having sulfonic acid group and optionally phosphonic acid group and satisfying either a condition that inherent viscosity measured in concentrated sulfuric acid is in the range of 0.25 to 10 dl/g or a condition that inherent viscosity measured in a methanesulfonic acid solution is in the range of 0.1 to 50 dl/g, wherein conductivity obtained by measuring complex impedance when applying a voltage of 10,000 Hz in frequency under conditions of 80° C. and 95% RH is in the range of 0.001 to 1.0 S/cm if said aromatic dicarboxylic acid bond unit contains phosphonic acid group and conductivity obtained by measuring complex impedance when applying a voltage of 10,000 Hz in frequency under conditions of 80° C. and 95% RH is in the range of 0.01 to 1.0 S/cm if said aromatic dicarboxylic acid bond unit contains no phosphonic acid group, and said polybenzazole compound including bond units consisting of components expressed in the following formulas (1) and (2) in a molar ratio n 1 :(1−n 1 ), said molar ratio satisfying an expression 0.5≦n 1 ≦1.0: (m 1 represents an integer of 1 to 4, B 1 represents a bivalent aromatic bond unit and each of A 1 and A 2 represents a bivalent bond unit expressed in either one of the following formulas (3) and (4) in each of the formulas (1) and (2) and A 1 and A 2 may be identical to or different from each other) (X represents either S atom or O atom in each of the formulas (3) and (4)).