Granted Patent
Utility
US 4,882,095 · App. 07/246,312
Preparation of alkoxy(iso)violanthrenediones
Inventors:
Reinhard Helwig, Helmut Hoch
Patented Case
View Patent ↗
Granted: Nov 21, 1989
Filed: Sep 19, 1988
Inventors
Reinhard Helwig
Helmut Hoch
Assignee (at issue)
BASF SE
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.