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:
May. 09, 2017
Filed:
Mar. 18, 2014
Kureha Corporation, Tokyo, JP;
Kazuyuki Yamane, Tokyo, JP;
Yoshiko Ikeyama, Tokyo, JP;
KUREHA CORPORATION, Tokyo, JP;
Abstract
A method for producing a GL comprising: (I) a heating step of heating a mixture either under normal pressure or reduced pressure at a temperature at which a polyglycolic acid (PGA) undergoes depolymerization, the mixture containing the PGA and a polyethylene glycol ether which is represented by the formula: X—O—(—CHCH—O—)—Y (wherein X and Y are each independently an alkyl group or an aryl group having from 2 to 20 carbon atoms, and p is an integer from 1 to 5) and which has a molecular weight of from 150 to 450 and a boiling point of from 130 to 220° C. at a pressure of 3 kPa; (II) a solution-forming step in which the mixture is rendered in a solution state in which a melt phase of the PGA and a liquid phase consisting of the polyethylene glycol ether essentially form a uniform phase; (III) a GL production step in which a glycolide (GL) is produced by a depolymerization reaction of the PGA by continuing to heat the mixture in the solution state; (IV) a distillation step of distilling off the produced GL together with the polyethylene glycol ether (B) from the depolymerization reaction system; and (V) a recovery step of recovering the GL from the distillate.