Thermotropic, wholly aromatic polyesters

A thermotropic, wholly aromatic polyester comprising condensed residues of monomeric units (a) through (e) wherein:

• (a) is p-hydroxyl-benzoic acid or p-hydroxyl-benzoic acid substituted in the nucleus by one or two C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy C.sub.6 -C.sub.10 aryl or C.sub.7 -C.sub.12 alkylaryl groups,
• (b) is 3-chloro-4-hydroxy-benzoic acid,
• (c) is isophthalic acid,
• (d) is hydroquinone and
• (e) is selected from 3,4'-dihydroxy-diphenyl, 4,4'-dihydroxydiphenyl, 3,4'-dihydroxy-diphenyl ether, 4,4'-dihydroxy-diphenyl sulphide, and mixtures thereof, wherein said polyester contains the condensed residues of
• (a) at a concentration of from 25 to 65 mol %,
• (b) at a concentration of from 5 to 40 mol %,
• (c) at a concentration of from 30 to 50 mol %, and
• (d) at a concentration of from 1 to 10 mol %,
• each based on the sum of the condensed residues (a), (b) and (c), with the proviso that the sum of concentrations of (a) and (b) amounts to a minimum of 50 mol % and a maximum of 70 mol % and that the molar ratio of the condensed residues c/(d+e) is from 0.95 to 1.05.