Patent ID: 6884265

Claim:
A composition for dyeing keratinous fibers comprising at least one dicationic diazo dye chosen from those of the following formula (I): W 1 —W 2 —N═N—W 3 —L—W 4 —N═N—W 5 —W 6 wherein: W 1 and W 6 , which may be identical or different, are each chosen from radicals NR 1 R 2 and OR; W 2 and W 5 , which may be identical or different, are each chosen from carbonaceous aromatic, pyridine and pyridazinyl groups of formula (II) W 3 and W 4 , which may be identical or different, are each chosen from heteroaromatic radicals of the following formulae (III) and (IV): wherein: X 1 is chosen from a nitrogen atom and radicals CR 5 ; X 2 is chosen from a nitrogen atom and radicals CR 6 ; Z 1 is chosen from an oxygen atom, a sulfur atom, and radicals NR 8 ; Z 2 is chosen from a nitrogen atom and radicals CR 9 ; Z 3 is chosen from a nitrogen atom and radicals CR 12 ; Z 4 is chosen from a nitrogen atom and radicals CR 13 ; N 1 of the 5-membered ring of formula (III) is connected to the group L and the bond a of the same 5-membered ring is connected to the azo group of formula (I); the bond b of the 6-membered ring of formula (IV) is connected to the azo group of formula (I) and N 1 of the 6-membered ring of formula (IV) is connected to the group L; L, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 9 , R 10 , R 11 , R 12 and R 13 , which may be identical or different, are each chosen from linear and branched C 1 -C 16 hydrocarbonaceous chains, which can form at least one ring chosen from 3- to 6-membered carbonaceous rings, and which can be saturated or unsaturated, wherein at least one carbon atom of the hydrocarbonaceous chains can be replaced by at least one entity chosen from oxygen, nitrogen, and sulfur atoms and an SO 2 group, and the at least one carbon atom of the hydrocarbonaceous chains can be substituted by at least one atom chosen from halogen atoms; R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 9 , R 10 , R 11 , R 12 and R 13 can each independently be a hydrogen atom; provided that L, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 9 , R 10 , R 11 , R 12 and R 13 do not comprise a peroxide bond, a diazo radical, or a nitroso radical, and L is a divalent radical; R 8 is chosen from linear and branched C 1 -C 8 alkyl radicals optionally substituted by at least one radical chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals; and from optionally substituted phenyl radicals; R 7 with R 9 , R 10 with R 11 and R 12 with R 13 can form a carbonaceous aromatic ring; R is a radical chosen from C 1 -C 3 alkyl radicals; and X − is an anion chosen from organic and inorganic anions.