High purity, clear, light stable, formaldehyde-free preservative compositions containing a compound formed by the reaction of excess glycine and formaldehyde at low temperatures

Granted: Jan 22, 2002 Filed: May 17, 2000

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.