Abstract: The present invention relates to liquid crystalline copoly(ester-imides) and a process for the preparation thereof. In particular, the invention relates to liquid crystalline copoly(esteri-imides) comprising structural units derived from N-(3'-hydroxyphenyl)-trimellitic acid imide or N-(4'-carboxyphenyl)trimellitic acid imides optionally in combination with aromatic dicarboxylic acids, dioles or hydroxy acids. The invention also concerns the use of these copolymers in polymer blends, in moulded articles, in fibres, filaments and sheets.

Abstract: A melt-processable block copolyesterimide comprising the repeating units (I), (II) and (III) and, optionally, a repeating unit (IV), wherein (I) is a repeating unit of the formula ##STR1## wherein R is an aliphatic polyether chain and/or a polysiloxane chain; (II) and (III) are repeating units of the formulas ##STR2## wherein Z is hydrogen, alkyl, alkoxy, aryl, halogen and w is zero or one; and (IV) is a repeating unit of the formula ##STR3## wherein Z' is hydrogen, alkyl, alkoxy, aryl or halogen and the phenylene ring is substituted in by Z' in the m- or p-positions. The repeating unit of formula (I) is present in an amount of 5 to 50 mole-%, the repeating unit of formula (II) is present in an amount of 10 to 80 mole-%, the repeating unit of formula (III) is present in an mount of 5 to 50 mole-% and the repeating unit of formula (IV) is present in an amount of 0 to 45 mole-% of the block copolyesterimide.