Granted Patent
Utility
US 4,992,251 · App. 07/244,898
Silicas
Inventors:
Derek Aldcroft, John R. Newton, Peter W. Stanier
Patented Case
View Patent ↗
Granted: Feb 12, 1991
Filed: Sep 15, 1988
Inventors
Derek Aldcroft
John R. Newton
Peter W. Stanier
Assignee (at issue)
Unilever Patent Holdings B.V.
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.