| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a copolymerized aromatic polyester causing less defects called flyspecks when formed into a film and the like even though a 6,6'-(alkylenedioxy)di-2-naphthoic acid component is copolymerized. Ž<P>SOLUTION: The copolymerized aromatic polyester is produced by subjecting an aromatic dicarboxylic acid lower alkyl ester, where a ratio of a 6,6'-(alkylenedioxy)di-2-naphthoic acid lower alkyl ester is ≥5 mol% and <80 mol%, and a polyalkylene glycol to a transesterification reaction and a polycondensation reaction. In this process, the transesterification reaction is carried out after melting and filtering the 6,6'-(alkylenedioxy)di-2-naphthoic acid lower alkyl ester in advance, and after completion of the transesterification reaction and completion of the polycondensation reaction, filtration is carried out again. In this way, the copolymerized aromatic polyester, where an amount of insoluble coarse foreign matter incapable of passing through a straight-hole filter of a pore size 5 μm is ≤100/mg, can be provided. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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