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:
Apr. 25, 1995
Filed:
Feb. 17, 1994
Suriyanarayanan Dorai, Hockessin, DE (US);
E. I. Du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
An improved method for recovering purified poly(tetramethylene ether) glycol or similar polyether polyol from an aqueous solution of polymer containing an alkaline metal catalyst residue involving the addition of a stoichiometric excess of magnesium sulfate or sulfite followed by evaporation of water and separation of molten polymer from precipitated solid phase (i.e., from magnesium hydroxide, alkaline metal sulfate/sulfite, and excess magnesium sulfate/sulfite). Such a process results in essentially complete removal of any basic transesterification catalyst and water without significant lost of poly(tetramethylene ether) glycol or the like.