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. 10, 2005
Filed:
Mar. 05, 2002
Kazuyuki Yamane, Fukushima, JP;
Yukichika Kawakami, Fukushima, JP;
Kazuyuki Yamane, Fukushima, JP;
Yukichika Kawakami, Fukushima, JP;
Kureha Kagaku Kogyo KK, Tokyo, JP;
Abstract
The invention provides a process for producing glycolide by depolymerization by heating of a glycolic acid oligomer in the presence or absence of a solvent, which process ensures stable depolymerization. The depolymerization reaction is carried out while the content of alkaline metal ions in a glycolic acid oligomer-containing depolymerization reaction system is controlled to 0.001% by mass or lower; a sulfate or an organic acid salt, each in the form of di- or poly-valent cations, or a mixture thereof is allowed to be present as a stabilizer in the depolymerization reaction system; or the content of alkaline metal ions in the depolymerization reaction system is controlled to 0.001% by mass or lower, and a sulfate or an organic acid salt, each in the form of di- or poly-valent cations, or a mixture thereof is allowed to be present as a stabilizer in the depolymerization reaction system.