Granted Patent
Utility
US 4,891,340 · App. 07/233,369
Preceramic compositions and ceramic products
Inventors:
John Semen, John J. Rogers
Patented Case
View Patent ↗
Granted: Jan 2, 1990
Filed: Aug 18, 1988
Inventors
John Semen
John J. Rogers
Assignee (at issue)
Ethyl Corporation
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.