Granted Patent
Utility
US 5,426,136 · App. 08/037,985
Particulate amorphous silica associated with thin polymeric film
Inventors:
Walter H. Waddell, Larry R. Evans, Jeffrey H. Harwell, John H. O'Haver
Patented Case
View Patent ↗
Granted: Jun 20, 1995
Filed: Mar 24, 1993
Inventors
Walter H. Waddell
Larry R. Evans
Jeffrey H. Harwell
John H. O'Haver
Assignee (at issue)
PPG Industries, 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.