4-(5',6'- and 6',7'-dihalobenzothiazol-2'-ylazo)-3-methyl-N-methyl-N-[(acetoxy or methoxycarbonyloxy)-C.sub.2-3 alkyl]anilines and mixtures thereof

Granted: Mar 31, 1992 Filed: May 25, 1990

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.