LIQUID-CRYSTALLINE POLYESTER AND PROCESS FOR PREPARING SAME

摘要

A liquid-crystalline polyester composed of structural units (I), (II), (III), (IV) and (V), characterized in that: the content of structural units (I) is 68 to 80mol% relative to the sum total of structural units (I), (II) and (III); the content of structural units (II) is 55 to 75mol% relative to the sum total of structural units (II) and (III); the content of structural units (IV) is 60 to 85mol% relative to the sum total of structural units (IV) and (V); the total molar content of structural units (II) and (III) is substantially equal to that of structural units (IV) and (V); and the ?S (entropy of melting) is 1.0 to 3.0 × 10-3J/g·K as defined by formula [1]: ?S(J/g·K) = ?Hm(J/g)/Tm(K) [wherein Tm is an endothermic peak temperature (Tm3) observed in differential scanning calorimetry of the liquid-crystalline polyester, and ?Hm is the area (?Hm3) of the endothermic peak at the Tm3, said Tm3 being determined by heating a specimen of the liquid-crystalline polyester from room temperature at a heating rate of 20°C/min to determine an endothermic peak temperature (Tm1), keeping the specimen at a temperature of Tm1+20°C for 5 minutes, cooling the specimen briefly to room temperature at a cooling rate of 20°C/min, heating the specimen again at a heating rate of 20°C/min to determine another endothermic peak temperature (Tm2), keeping the specimen at a temperature of Tm1+20°C for 5 minutes, cooling the specimen briefly to room temperature at a cooling rate of 20°C/min, and then heating the specimen again at a heating rate of 20°C/min to determine another endothermic peak temperature, namely, Tm3].