Patent ID: 7393467

Claim:
A liquid-crystalline polyester, which has a deflection temperature under load (DTUL) of 290-340° C.; the difference between the DTUL and the crystalline melting temperature of the liquid-crystalline polyester determined by differential scanning calorimetry is equal to or less than 40° C.; and which is obtained by subjecting a prepolymer consisting of the repeating units of formulae (I), (II), (III) and (IV): wherein, p, q, r and s represent relative molar proportions (mol %) of the repeating units in the prepolymer and satisfy the following formulae: 60 ≦p+q ≦78 0.05 ≦q ≦3 11 ≦r ≦20 and 11 ≦s ≦20 to heat treatment in a solid state.