Granted Patent
Utility
US 4,772,490 · App. 06/942,155
Method for producing a water-permeable covering on granular water-soluble substances
Inventors:
Hubert Kogler, Reinhard Winter, Peter Kuhlmann
Patented Case
View Patent ↗
Granted: Sep 20, 1988
Filed: Dec 16, 1986
Inventors
Hubert Kogler
Reinhard Winter
Peter Kuhlmann
Assignee (at issue)
Ashland Oil, 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.