| 摘要 |
<p>PURPOSE:To obtain high-quality bishydroxyethyl terephthalate and/or its oligomer, by depolymerizing a waste polyester composed mainly of ethylene terephthalate under a specific condition in a short time. CONSTITUTION:A bishydroxyethyl terephthalate and/or its oligomer (abbreviated as BHT) wherein the equivalent ratio of the glycol component to the acid component is 1.3-2.0 is charged in a reaction vessel in molten state. Ethylene glycol and waste polyester are added simultaneously and continuously to the reaction vessel, and the waste polyester composed mainly of ethylene terephthalate is depolymerized by keeping the equivalent ratio of the glycol component to the acid component to 1.3-2.0 and keeping the temperature of the depolymerization reaction system at 215-250 deg.C under stirring. The polyester prepared by the polymerization of the BHT obtained by the depolymerization has high softening point, excellent color tone, low content of foreign materials, and high quality.</p> |
