| 摘要 |
PURPOSE:To obtain the title polyester which is excellent in moldability and can give a molding excellent in mechanical and thermal properties, comprising four specified kinds of recurring units. CONSTITUTION:A 4-hydroxybenzoic acid (derivative) (A) is polymerized by melting with terephthalic acid (derivative) (B), 4,4'-dihydroxydiphenyl (derivative) (C) and 4,4'-dihydroxydiphenyl ether (derivative) at 200-400 deg.C for 1-10hr in the presence of, optionally, 0.001-1wt.% polymerization catalyst in an inert gas atmosphere or in a vacuum to obtain the title polyester comprising 30-80mol.% units of formula I (wherein at least part of the hydrogen atoms. bonded to the ring may be replaced by substituents: the same applies also in formulas II-IV), 10-35mol.% units of formula II, 2.5-25mol.% units of formula III and 5-30mol.% units of formula IV (the total of units of formula III and units of formula IV is substantially equimolar to units of formula II), having a logarithmic viscosity >=0.5dl/g (as determined in pentafluorophenol in a 0.1wt./ vol. concentration at 60 deg.C) and can form an optically anisotropic molten phase at 375 deg.C or below.
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