Patent ID: 8551189

Claim:
A process for dyeing keratin fibres, comprising treating the fibres with: i) at least one 1,8-dihydroxynaphthalene derivative of formula (I): inorganic or organic acids or bases, optical isomers, geometric isomers, tautomers, and/or solvates thereof, wherein: R 1 and R 6 are, independently of one another, chosen from: hydrogen atoms, C 1 -C 4 alkyl radicals which can be functionalized with at least one hydroxyl or (C 1 -C 4 )alkoxycarbonyl radical, carboxylic radicals —CO 2 H, (C 1 -C 4 )alkoxycarbonyl radicals, (C 1 -C 4 )alkylcarbonyl radical which can be functionalized with a (C 1 -C 4 )alkylcarbonyl radical or a (C 1 -C 4 )alkoxycarbonyl radical, C 1 -C 4 alkoxy radicals, carboxaldehyde radicals —CHO, and sulphonic radicals —SO 3 H; R 2 and R 5 are, independently of one another, chosen from: hydrogen atoms, hydroxyl radicals, C 1 -C 4 alkyl radicals which can be functionalized with at least one hydroxyl or (C 1 -C 4 )alkoxycarbonyl radical, carboxylic radicals —CO 2 H, (C 1 -C 4 )alkoxycarbonyl radicals, (C 1 -C 4 )alkylcarbonyl radicals which can be functionalized with a hydroxyl radical, carboxaldehyde radicals —CHO, and sulphonic radicals —SO 3 H; R 3 and R 4 are, independently of one another, chosen from: hydrogen atoms, hydroxyl radicals, C 1 -C 4 alkyl radicals which can be functionalized with at least one hydroxyl and (C 1 -C 4 )alkoxycarbonyl radical, carboxylic radicals —CO 2 H, (C 1 -C 4 )alkoxycarbonyl radicals, and (C 1 -C 4 )alkylcarbonyl radicals which can be functionalized with a (C 1 -C 4 )alkylcarbonyl radical or a (C 1 -C 4 )alkoxycarbonyl radical; R 1 and R 2 can form, together with the carbon atoms to which they are attached, a heterocycle optionally substituted with an oxo group, optionally functionalized with one or two C 1 -C 4 alkyl radicals: with R and R′, which may be identical or different, representing a hydrogen atom or a C 1 -C 4 alkyl radical; and ii) at least one basifying agent other than aqueous ammonia; wherein: the at least one 1,8-dihydroxynaphthalene derivative of formula (I) and the at least one basifying agent can be applied simultaneously or successively to the keratin fibers, and wherein the dyeing process does not involve aqueous ammonia.