Granted Patent
Utility
US 4,508,536 · App. 06/551,393
Solid dye mixtures for dyeing polyacrylonitrile navy blue to black
Inventors:
Paul Erzinger, Arnulf Ruediger Lapple
Patented Case
View Patent ↗
Granted: Apr 2, 1985
Filed: Nov 14, 1983
Inventors
Paul Erzinger
Arnulf Ruediger Lapple
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.