The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 12, 2005
Filed:
Aug. 08, 2001
Kazuyuki Yamane, Fukushima, JP;
Yukichika Kawakami, Fukushima, JP;
Hajime Hoshi, Fukushima, JP;
Kazuhiko Sunagawa, Fukushima, JP;
Kazuyuki Yamane, Fukushima, JP;
Yukichika Kawakami, Fukushima, JP;
Hajime Hoshi, Fukushima, JP;
Kazuhiko Sunagawa, Fukushima, JP;
Kureha Kagaku Kogyo K.K., Tokyo, JP;
Abstract
The present invention provides a process for production of a cyclic ester by depolymerization of an aliphatic polyester. In the process, a mixture containing the aliphatic polyester and a specific polyalkylene glycol ether, which has a boiling point of 230-450° C. and a molecular weight of 150-450, is heated under normal or reduced pressure to a temperature at which depolymerization of the aliphatic polyester takes place. Then, a substantially homogeneous solution phase, consisting of the melt phase of the aliphatic polyester and the liquid phase of the polyalkylene glycol ether, is formed. Heating of the solution phase is continued to form the cyclic ester by depolymerization and distil out the cyclic ester together with the polyalkylene glycol ether, and then the cyclic ester is recovered from the distillate. The present invention also provides a process for purification of a crude cyclic ester by use of the specific polyalkylene glycol ether described above.