Granted Patent
Utility
US 4,447,408 · App. 06/447,720
Phosphonitrilic chloride polymers
Inventor:
Hsueh M. Li
Patented Case
View Patent ↗
Granted: May 8, 1984
Filed: Dec 7, 1982
Inventor
Hsueh M. Li
Assignee (at issue)
Ethyl Corporation
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.