Granted Patent
Utility
US 5,942,031 · App. 08/762,848
Expanding additive for cement composition
Inventor:
Ping-Sun Cheung
Patented Case
View Patent ↗
Granted: Aug 24, 1999
Filed: Dec 10, 1996
Inventor
Ping-Sun Cheung
Assignee (at issue)
Nalco/Exxon Energy Chemicals, L.P.
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.