Granted Patent
Utility
US 4,979,681 · App. 07/440,590
Process for grinding and simultaneous drying of moist cellulose ether products
Inventors:
Reinhard Donges, Manfred Sponheimer, Gunther Welt, Manfred Ziegelmayer
Patented Case
View Patent ↗
Granted: Dec 25, 1990
Filed: Nov 22, 1989
Inventors
Reinhard Donges
Manfred Sponheimer
Gunther Welt
Manfred Ziegelmayer
Assignee (at issue)
Hoechst GmbH
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.