Granted Patent
Utility
US 4,581,213 · App. 06/688,454
Crystalline silicic acid, its salts, and processes for their preparation
Inventor:
Hans-Peter Rieck
Patented Case
View Patent ↗
Granted: Apr 8, 1986
Filed: Jan 2, 1985
Inventor
Hans-Peter Rieck
Assignee (at issue)
Hoechst GmbH
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.