Granted Patent
Utility
US 4,921,689 · App. 07/211,309
Process for producing beta manganese dioxide
Inventors:
Andre Laddarrel Walker, Terrence F. Reise
Patented Case
View Patent ↗
Granted: May 1, 1990
Filed: Jun 24, 1988
Inventors
Andre Laddarrel Walker
Terrence F. Reise
Assignee (at issue)
Duracell Inc.
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.