Granted Patent
Utility
US 4,820,309 · App. 07/163,442
1:2-chromium complex dyes for tanned leather
Inventor:
Herbert Holliger
Patented Case
View Patent ↗
Granted: Apr 11, 1989
Filed: Mar 3, 1988
Inventor
Herbert Holliger
Assignee (at issue)
Sandoz AG
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.