Granted Patent
Utility
US 4,421,728 · App. 06/396,125
Stabilization of red phosphorus
Inventor:
Helena Twardowska
Patented Case
View Patent ↗
Granted: Dec 20, 1983
Filed: Jul 7, 1982
Inventor
Helena Twardowska
Assignee (at issue)
ERCO Industries Limited
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.