Granted Patent
Utility
US 4,116,983 · App. 05/800,141
Two stage maleic anhydride process
Inventor:
John P. Schmidt
Patented Case
View Patent ↗
Granted: Sep 26, 1978
Filed: May 24, 1977
Inventor
John P. Schmidt
Assignee (at issue)
Halcon International, 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.