Method of improving the contaminant resistance of a smectite clay by rewetting and impregnating the clay with a water-soluble polymer, and redrying the polymer-impregnated clay

Granted: Apr 18, 1995 Filed: Sep 29, 1993

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.