| 摘要 |
PURPOSE:To obtain the titled polyester economically by a smooth reaction using a recovered glycol, by adjusting the amount of acetic acid (ester) within a specific range and reacting a dicarboxylic acid with butanediol in the presence of a tin compound. CONSTITUTION:(A) A dicarboxylic acid consisting essentially of terephthalic acid is mixed with (B) a recovered glycol, consisting essentially of 1,4-butanediol, and adjusted to contain acetic acid and glycol ester thereof in an amount within 0.01-10wt% range expressed in terms of acetic acid based on the component (A), and (C) a tin compound, e.g. tetraethyltin, in an amount of preferably 0.001-0.5wt% based on the polymer weight is added thereto to esterify the dicarboxylic acid (A) at 100-250 deg.C. Polycondensation is then carried out to give the aimed polyester. The glycol ester of the acetic acid is removed by rectifying or saponifying the component (B) recovered from the polycondensation step, etc., and the amount thereof is adjusted for reuse.
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