Granted Patent
Utility
US 4,976,744 · App. 07/406,244
Preparation of concentrated solutions of cationic dyes as mono-carboxylates in glycol ether
Inventors:
Johannes P. Dix, Guenter Hansen, Hellmut Kast
Patented Case
View Patent ↗
Granted: Dec 11, 1990
Filed: Sep 12, 1989
Inventors
Johannes P. Dix
Guenter Hansen
Hellmut Kast
Assignee (at issue)
BASF SE
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.