Granted Patent
Utility
US 4,740,547 · App. 07/049,873
Aromatic polysulfone thermoplastics protected from discoloration during thermal processing
Inventor:
Yuyal Halpern
Patented Case
View Patent ↗
Granted: Apr 26, 1988
Filed: May 14, 1987
Inventor
Yuyal Halpern
Assignee (at issue)
Borg-Warner Chemicals, Inc.
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.