DIAZO DYE

PROBLEM TO BE SOLVED: To dye a cellulose material, esp. paper, cotton, viscose, or leather, in a blue tone with good resistances to wetting treatment and light by using a specific new diazo dye for dyeing the material. SOLUTION: This dye is represented by formula I (wherein A is a group represented by formula II or III; Ac is acetyl, propionyl, CH3 , CH3 O, or carboxylated benzoyl; m, n, p, and q are each 0 or 1 provided m+n is 1; and R is H, CH3 , CH3 O, or carboxylated benzoyl provided when m=1, n=0, and q=0, then R is not H) and can be used in a method wherein various bleached or unbleached materials, e.g. cellulose sulfate and/or cellulose sulfite derived from softwood or hardwood, is used. The dye can dye threads or small articles of cotton, viscose, or linen with a long dye bath by the exhaust method. A liq. preparation of the dye generally contains at least one kind of the dye in a concn. of 10-40wt.%.