Kabushiki Kaisha Ueno Seiyaku Oyo Kenkyujo

Tetsuhide Sawada

Hiroyuki Kato

Motoki Asahara

Provided is a liquid-crystalline polyester with good properties obtainable by subjecting a prepolymer consisting of the repeating units represented by formulae (I), (II), (III) and (IV): to heat treatment in a substantially solid state.

Wholly aromatic liquid-crystalline polyester and method for preparing the same

The present invention provides a liquid-crystalline polyester obtainable by a method comprising the steps of: (1) preparing a prepolymer consisting of the repeating units represented by formulae (I), (II), (III) and (IV): wherein, p, q, r and s represent relative molar proportions (mol %) of the repeating units in the liquid-crystalline polyester resin and satisfy the following formulae: 60&#x2266;p&#x2266;80, 10&#x2266;r&#x2266;20, 10&#x2266;q+s&#x2266;20, 0.05&#x2266;s/(q+s)&#x2266;0.3, p+q+r+s=100; and (2) heating the prepolymer in substantially solid state at 250-350&#xb0; C., provided that the liquid crystalline polyester has a deflection temperature under load of 280-340&#xb0; C., and a melt viscosity of 10-60 Pa&#xb7;s.

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Nishinomiya, Japan

Tetsuhide Sawada