Granted Patent
Utility
US 4,959,464 · App. 07/268,287
Process for derivatizing polygalactomannan using water soluble aluminum salts in the process
Inventor:
Michael Yeh
Patented Case
View Patent ↗
Granted: Sep 25, 1990
Filed: Nov 7, 1988
Inventor
Michael Yeh
Assignee (at issue)
Hi-Tek Polymers, 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.