Patent ID: 7722680

Claim:
A method for dyeing human keratin materials, comprising: applying at least one direct azo dye contained in a dry composition directly to or close to the keratin materials, and applying heat; wherein the at least one direct azo dye is chosen from azo dyes of formula (I): wherein: n and n′ are integers that are independently chosen from 1 to 5; R and R′ are independently chosen from: a hydrogen atom; a saturated, unsaturated, aromatic, linear, branched, or cyclic, C 1 -C 30 hydrocarbon chain that is optionally substituted with at least one group chosen from halogen atoms, hydroxyl, nitro, cyano, carboxylic acid, allyl, haloallyl, C 1 -C 10 alkoxy, (C 1 -C 4 )alkylcarbonyl(C 1 -C 4 )amino, (C 1 -C 4 )alkylaminocarbonyl, hydrogeno -carbonylamino, (C 1 -C 4 )alkylsulphonylamino, (C 1 -C 4 )alkoxycarbonylamino, (C 1 -C 4 )alkoxycarbonyl, (C 1 -C 4 )alkylcarbonyl(C 1 -C 4 )alkoxycarbonyl, CF 3 , and amino optionally substituted with at least one radical chosen from C 1 -C 10 alkyl, C 1 -C 10 hydroxyalkyl, alkoxy(C 1 -C 10 )alkyl, C 1 -C 10 aminoalkyl, (C 1 -C 10 )(di)alkyl -amino(C 1 -C 10 )alkyl, C 1 -C 10 cyanoalkyl, C 6 -C 30 aryl, (C 6 -C 30 )aryl(C 1 -C 4 )alkyl, (C 4 -C 30 )cyclo(C 1 -C 12 )alkyl, (C 1 -C 4 )alkylcarbonyl, (C 1 -C 4 )alkylcarboxy(C 1 -C 4 )alkyl, allyl, and haloallyl radicals; and optionally interrupted or attached to the aromatic ring to which they are attached by at least one heteroatom or group comprising at least one heteroatom, wherein said at least one heteroatom is chosen from O, S, and N; and a hydroxyl group, C 1 -C 4 alkoxy, carboxylic acid, halogen, allyl, hydrogenocarbonyl, trifluoromethyl, nitro, cyano, and amino optionally substituted with at least one radical chosen from C 1 -C 4 alkyl, C 2 -C 4 alkenyl, C 1 -C 4 cyanoalkyl, C 1 -C 4 hydroxyalkyl, C 6 -C 30 aryl, (C 6 -C 30 )aryl(C 1 -C 4 )alkyl, allyl, (C 1 -C 4 )alkoxy(C 1 -C 4 )alkyl, (C 4 -C 30 )cyclo(C 1 -C 12 )alkyl, (C 1 -C 4 )alkylcarbonyl, (C 1 -C 4 )alkylcarboxy(C 1 -C 4 )alkyl, haloallyl, C 1 -C 4 amino-alkyl, (C 1 -C 4 )(di)alkylamino(C 1 -C 4 )alkyl, (C 1 -C 4 )alkylsulphonyl, and (C 1 -C 4 )alkoxycarbonyl radicals; wherein: at least one of radicals R or R′ is chosen from hydroxyl, nitro, cyano, and amino optionally substituted with at least one radical; and two radicals of R or R′ attached to two adjacent carbon atoms may optionally form, together with the aromatic ring carrying the carbon atoms to which each is attached, a fused napthalene ring that is optionally substituted with at least one group chosen from aminosulphonyl and (C 1 -C 4 )alkyl(C 1 -C 4 )aminosulphonyl.