Granted Patent
Utility
US 4,400,518 · App. 06/346,465
Composition of matter and process
Inventor:
Wendell Wierenga
Patented Case
View Patent ↗
Granted: Aug 23, 1983
Filed: Feb 8, 1982
Inventor
Wendell Wierenga
Assignee (at issue)
The Upjohn Co.
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.