Granted Patent
Utility
US 4,640,832 · App. 06/772,395
Process for the production of sodium polysulfides from the elements sodium and sulfur
Inventors:
Friedrich Bittner, Walter Hinrichs, Herbert Hovestadt, Ludwig Lange, Erich Splett
Patented Case
View Patent ↗
Granted: Feb 3, 1987
Filed: Sep 4, 1985
Inventors
Friedrich Bittner
Walter Hinrichs
Herbert Hovestadt
Ludwig Lange
Erich Splett
Assignee (at issue)
Degussa AG
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.