Granted Patent
Utility
US 4,820,439 · App. 07/020,079
Washing and cleaning agent containing surfactants, builder, and crystalline layered sodium silicate
Inventor:
Hans-Peter Rieck
Patented Case
View Patent ↗
Granted: Apr 11, 1989
Filed: Feb 27, 1987
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.