Granted Patent
Utility
US 5,004,506 · App. 07/502,974
Welan gum in cement compositions
Inventors:
Floyd L. Allen, Glen H. Best, Thomas A. Lindroth
Patented Case
View Patent ↗
Granted: Apr 2, 1991
Filed: Apr 2, 1990
Inventors
Floyd L. Allen
Glen H. Best
Thomas A. Lindroth
Assignee (at issue)
MERCK & CO., 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.