Granted Patent
Utility
US 5,326,457 · App. 07/925,160
Process for making carbon electrode impregnating pitch from coal tar
Inventor:
John Stipanovich, Jr.
Patented Case
View Patent ↗
Granted: Jul 5, 1994
Filed: Aug 6, 1992
Inventor
John Stipanovich, Jr.
Assignee (at issue)
Aristech Chemical Company
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.