Granted Patent
Utility
US 4,298,728 · App. 06/155,919
Method of preparing hydroxyethyl ethers of cellulose
Inventors:
Thomas G. Majewicz, Walter S. Ropp
Patented Case
View Patent ↗
Granted: Nov 3, 1981
Filed: Jun 3, 1980
Inventors
Thomas G. Majewicz
Walter S. Ropp
Assignee (at issue)
HERCULES LLC
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.