Granted Patent
Utility
US 5,756,757 · App. 08/559,551
Process for the preparation of 3-hydroxy-N-benzimidazolon-5-yl-2-naphthamide in the high purity required of azo pigments
Inventors:
Michael Meier, Heinrich Volk, Rudolf Neeb
Patented Case
View Patent ↗
Granted: May 26, 1998
Filed: Nov 16, 1995
Inventors
Michael Meier
Heinrich Volk
Rudolf Neeb
Assignee (at issue)
Hoechst GmbH
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.