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:
Dec. 28, 1993
Filed:
Aug. 24, 1992
Patrick R Gruber, St. Paul, MN (US);
Eric S Hall, Crystal, MN (US);
Jeffrey J Kolstad, Wayzata, MN (US);
Matthew L Iwen, Minneapolis, MN (US);
Richard D Benson, Long Lake, MN (US);
Ronald L Borchardt, Eden Prairie, MN (US);
Cargill, Incorporated, Minneapolis, MN (US);
Abstract
A process for the continuous conversion of crude lactic acid to a substantially purified lactide or polylactide including the steps of polymerizing the lactic acid to form a prepolymer with subsequent depolymerization to form a crude lactide in the presence of a catalyst. The crude lactide is purified in an improved distillation system in which at least three fractions are formed with the substantially purified lactide removed as an intermediate boiling sidedraw stream. The substantially purified lactide may then be polymerized.