Azo compounds having 2,4-disubstituted-3-halothienyl-5-diazo component radicals, dyeing processes therewith and substrates dyed therewith

Granted: Jul 21, 1992 Filed: Mar 19, 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.