| 摘要 |
<p>PURPOSE:To produce advantageously a specified polyester, by recycling a solution prepared by adjusting the insoluble component concentration and Ge compound concentration of a distrillate out of polycondensation to specified values as a catalyst solution in the production of a specified polyester. CONSTITUTION:A polyester is produced by polycondensing bis-beta-hydroxyethyl terephthalate and/or its low polymer in the presence of a germanium compound catalyst. In recycling a germanium compound-containing distillate formed during polycondensation by adding it to the polycondensation system as a catalyst solution, insoluble components are separated from it so that their concentration may be decreased to 1wt% or below, and this distillate is treated with an adsorbent to obtain a solution of a germanium compound concentration of 0.1-1wt% (in terms of germanium metal). This solution is fed to the reaction system. Examples of the germanium compounds include germanium dioxide, germanium phosphate, germanium chloride and germanium butoxide.</p> |
