Granted Patent
Utility
US 5,228,905 · App. 07/795,410
Water-borne treatment compositions for porous substrates
Inventors:
John F. Grunewalder, Mark A. Voelker
Patented Case
View Patent ↗
Granted: Jul 20, 1993
Filed: Nov 20, 1991
Inventors
John F. Grunewalder
Mark A. Voelker
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.