Granted Patent
Utility
US 5,424,452 · App. 08/257,394
Diketopyrrolopyrroles and pigments thereof
Inventors:
Gary Wooden, Guy de Weck, Olof Wallquist
Patented Case
View Patent ↗
Granted: Jun 13, 1995
Filed: Jun 9, 1994
Inventors
Gary Wooden
Guy de Weck
Olof Wallquist
Assignee (at issue)
Ciba-Geigy
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.