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:
Aug. 04, 1981
Filed:
Aug. 21, 1980
Applicant:
Inventors:
Oscar R Buehler, Newark, DE (US);
Harold F Porter, Hockessin, DE (US);
Assignee:
E. I. Du Pont de Nemours and Company, Wilmington, DE (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
564498 ; 260707 ;
Abstract
Hexamethylenediamine (HMD) is purified by dissolving ammonia in crude molten HMD under pressure, directing the solution thus prepared to a reduced pressure zone where the ammonia is vaporized thereby causing a portion of the HMD to crystallize following which the crystals in the slurry are washed with essentially pure HMD. This purified HMD is suitable for conversion into polyamide fibers.