Granted Patent
Utility
US 4,494,989 · App. 06/399,916
Compounds, processes and marking systems
Inventors:
Paul Schmidt, William M. Hung
Patented Case
View Patent ↗
Granted: Jan 22, 1985
Filed: Jul 19, 1982
Inventors
Paul Schmidt
William M. Hung
Assignee (at issue)
Hilton Davis Chemical 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.