Granted Patent
Utility
US 5,075,458 · App. 07/684,873
Purification of indigo
Inventors:
Reinhold Kohlhaupt, Manfred Gaeng, Lothar Haas, Guenter Engelhardt, Walter Bieg, Matthias Fankhaenel
Patented Case
View Patent ↗
Granted: Dec 24, 1991
Filed: Apr 15, 1991
Inventors
Reinhold Kohlhaupt
Manfred Gaeng
Lothar Haas
Guenter Engelhardt
Walter Bieg
Matthias Fankhaenel
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.