Granted Patent
Utility
US 4,923,916 · App. 07/221,053
Tetrahalophthalate esters as flame retardants for polystyrene resins
Inventors:
Joseph M. Bohen, Ronald F. Lovenguth
Patented Case
View Patent ↗
Granted: May 8, 1990
Filed: Jul 19, 1988
Inventors
Joseph M. Bohen
Ronald F. Lovenguth
Assignee (at issue)
Pennwalt 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.