| 摘要 |
PURPOSE:To obtain a polyester which can give a molded product small in anisotropy of mechanical properties and excellent in impact resistance and heat resistance, comprising repeating 4-oxybenzoyl, terephthaloyl and 4,4'- dioxydiphenyl ether units. CONSTITUTION:A thermotropic liquid crystal polyester comprising repeating units I of formula I, repeating units II of formula II and repeating units II of formula III (at least part of the hydrogen atoms bonded to the rings may be substituted), wherein units I are present in an amount in the range of 45-68mol%, units II are present in an amount in the range of 16-27.5mol%, and units III are present in an amount in the range of 16-27.5mol%, provided that units II and III are present in equimolar amounts, said polyester having a logarithmic viscosity >=0.5dl/g when measured in pentafluorophenol in a 0.1wt.%/vol.% at 60 deg.C and forming an optically anisotropic melt phase at a temperature <=350 deg.C. |
