Mitsubishi Gas Chemical Company, Inc.

Mashahiro Harada

Senzo Shimizu

Isao Nomura

Motohachi Usui

A process for producing an aromatic polyester copolymer wherein the alternating configuration of the components making up the copolymer is highly regular, said process comprising a first step of reacting a dihydric phenolic compound with an aromatic dicarboxylic acid dichloride A in a reaction medium consisting of water and a water-immiscible solvent in the presence of a basic inorganic compound to give a phenolic hydroxyl-terminated aromatic oligoester containing predominantly an oligomer having a degree of polymerization of 1-2, and a second step of reacting the aromatic dihydroxy oligoester obtained in the first step with an aromatic dicarboxylic acid dichloride B in the presence of a basic inorganic compound in an amount at least sufficient to neutralize the free phenolic hydroxyl groups remaining in the reaction product mixture obtained in the first step.

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Hiratsuki, Japan

Mashahiro Harada