Granted Patent
Utility
US 4,375,987 · App. 06/324,338
Additive combination for hydraulic cement compositions
Inventors:
Bruce A. Lange, Heyman C. Duecker
Patented Case
View Patent ↗
Granted: Mar 8, 1983
Filed: Nov 23, 1981
Inventors
Bruce A. Lange
Heyman C. Duecker
Assignee (at issue)
W. R. Grace & 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.