| abstract |
Water sol azo dyes of the 2,6-diaminopyridine series which in the free acid form have the formula: where D is the residue of a diazo component, E = H, opt. subst. alkyl or phenyl, Z = CN or carboxylic amide gp., R = H or opt. subst. aliphatic, araliphatic, cycloaliphatic or aromatic grp. or two grps. R together with the N atom form a satd. heterocyclic ring and n = 1, 2 or 3. The dyes have yellow to reddish blue tints and are esp. useful for dyeing natural and synthetic polyamides such as wool, silk, polycaprolactam and nylon, 6,6 in fast shades with excellent light resistance. |