| 摘要 |
PURPOSE:To carry out depolymerization of a polymer to monomers which can be regenerated to a polymer having high polymerization degree and excellent transparency by repolymerization, by adding butanediol to a polybutylene terephthalate polymerized in the presence of a specific catalyst and heating the mixture under reduced pressure. CONSTITUTION:(A) A polybutylene terephthalate produced by the polymerization of a dicarboxylic acid component composed mainly of terephthalic acid and a glycol component composed mainly of 1,4-butanediol in the presence of an organic titanium compound of formula (R is alkyl, etc.) (e.g. tetramethyl titanate) is depolymerized by adding (B) preferably 0.2-2.0mol of 1,4-butanediol (based of 1mol of the dicarboxylic acid of the component A) and heating the mixture e.g. at 210-250 deg.C under a pressure of <=700Torr.
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