Granted Patent
Utility
US 4,698,295 · App. 06/796,380
Polyimides, a process for their preparation and their use, and tetracarboxylic acids and tetracarboxylic acid derivatives
Inventors:
Josef Pfeifer, Rudolf Duthaler
Patented Case
View Patent ↗
Granted: Oct 6, 1987
Filed: Nov 8, 1985
Inventors
Josef Pfeifer
Rudolf Duthaler
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.