Granted Patent
Utility
US 5,368,640 · App. 08/134,586
Transparent iron oxide pigments, processes for their production and their use
Inventors:
Ulrike Pitzer, Klaus Lerch, Gunter Buxbaum
Patented Case
View Patent ↗
Granted: Nov 29, 1994
Filed: Oct 12, 1993
Inventors
Ulrike Pitzer
Klaus Lerch
Gunter Buxbaum
Assignee (at issue)
Bayer Aktiengesellschaft
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.