The present invention relates to a dye composition comprising 12-hydroxystearic acid, at least one organic amine and at least one dye, to a ready-to-use composition and to a kit comprising said dye composition, and to a dyeing process using said dye composition.

Many people have for a long time sought to modify the colour of their hair, and in particular to dye it, for example in order to mask their grey hair.

In order to dye human keratin fibres durably, "permanent" dyeing methods, also known as oxidation dyeing, have been developed. These methods use dye compositions containing oxidation dye precursors, generally known as oxidation bases, such as ortho- or para-phenylenediamines, ortho- or para-aminophenols and heterocyclic compounds. These oxidation bases are colourless or weakly coloured compounds, which, when combined with oxidizing products, may give rise to coloured compounds via a process of oxidative condensation.

It is also known that the shades obtained with these oxidation bases may be varied by combining them with couplers or colour modifiers, the latter being chosen especially from aromatic meta-diaminobenzenes, meta-aminophenols, meta-diphenols and certain heterocyclic compounds such as indole compounds.

The second type of dyeing is "semi-permanent" dyeing or direct dyeing, which consists in applying, to the keratin fibres, direct dyes, which are coloured and colouring molecules that have affinity for said fibres, in leaving them on for a time, and then in rinsing them off.

In order to perform these dyeing operations, the direct dyes generally used are chosen from nitrobenzene, anthraquinone, nitropyridine, azo, xanthene, acridine, azine and triarylmethane direct dyes, and natural dyes.

Compositions containing one or more direct dye(s) are applied to the keratin fibres for a time necessary to obtain the desired colouring, and are then rinsed off.

The colourings that result therefrom are generally chromatic colourings which are, however, temporary or semi-permanent since the nature of the interactions that bind the direct dyes to the keratin fibre and their desorption from the surface and/or the core of the fibre are responsible for their weak dyeing power and their poor persistence with respect to washing or perspiration.

To improve this direct dyeing, it has been proposed to perform it as oxidation dyeing in the presence of oxidizing agents. This is then referred to as lightening direct dyeing.

The dye compositions are generally in the form of solutions, gels or more or less fluid creams. However, the working qualities and the stability of these compositions remain to be improved. Now, users of cosmetic products are in search of products that are pleasant to use, which spread well, rinse out easily and are stable, especially on storage.

The Applicant has now discovered that a dye composition comprising 12-hydroxystearic acid, at least one organic amine and at least one dye as defined below, used in a dyeing process, makes it possible to obtain a texture with good working qualities, especially in terms of ease of application and ease of rinsing, whether it is used alone, sequentially or as a mixture with an oxidizing composition.

This dye composition shows improved stability over time. It is easy to use, i.e. it can especially be spread easily from the roots to the ends and is easy to rinse out, and thus has a reduced impact on the environment (less consumption of water), while at the same time having good dyeing properties especially in terms of intensity, build-up and selectivity.

For the purposes of the present invention, the term "stable over time" means that the visual appearance and the viscosity of the compositions do not change or do not substantially change (variation generally less than 10% relative to the viscosity at TO) over time under standard or non-standard storage conditions, for example for one month or two months following the manufacture of said compositions, at 4°C, at room temperature (20-25°C), at 45°C, and up to temperatures of 60°C. It also means that the performance obtained does not change or does not substantially change during the storage of the formulations.

In addition, they are very easy to rinse out.

One subject of the present invention is thus a dye composition comprising

12-hydroxystearic acid, one or more organic amines and one or more dyes chosen from oxidation dyes and direct dyes.

The invention also relates to a ready-to-use composition for the oxidation dyeing of keratin fibres and in particular of human keratin fibres such as the hair, comprising the extemporaneous mixing of a dye composition (A) according to the invention and of an oxidizing composition (B).

Another subject of the invention is a dyeing kit comprising, first, a dye composition (A) according to the invention, and, secondly, an oxidizing composition (B).

A subject of the invention is also a process for dyeing keratin fibres, especially human keratin fibres such as the hair, using said ready-to-use composition.

Other characteristics and advantages of the invention will emerge more clearly on reading the description and the examples that follow.

In the text hereinbelow, and unless otherwise indicated, the limits of a range of values are included within that range, especially in the expressions "between" and "ranging from ... to

Moreover, the expression "at least one" used in the present description is equivalent to the expression "one or more".

According to the invention, the dye composition comprises 12-hydroxystearic acid, one or more organic amines and one or more dyes chosen from oxidation dyes and direct dyes.

Preferably, 12-hydroxystearic acid is present in an amount ranging from 0.1% to 40% by weight, better still from 1% to 30%> by weight and even better still from 5% to 25% by weight, relative to the total weight of the dye composition.

The organic amine(s) are preferably chosen from organic amines with a pKb at 25°C of less than 12, preferably less than 10 and even more advantageously less than 6. It should be noted that it is the pKb corresponding to the function of highest basicity. In addition, the organic amines do not comprise any alkyl or alkenyl fatty chain comprising more than ten carbon atoms.

The organic amine(s) are chosen, for example, from alkanolamines, oxyethylenated and/or oxypropylenated ethylenediamines, amino acids and the compounds of formula (P) below:

R*\ N - W - N A

/
Ry *< (P)

in which W is a divalent Ci to C6 alkylene group optionally substituted with one or more hydroxyl groups or a Ci to C6 alkyl group, and/or optionally interrupted with one or more heteroatoms such as O, or NRU; Rx, Ry, Rz, Rt and Ru, which may be identical or different, represent a hydrogen atom or a Ci to C6 alkyl, Ci to C6 hydroxyalkyl or Ci to C6 aminoalkyl group.

Examples of amines of formula (P) that may be mentioned include 1,3-diaminopropane, l,3-diamino-2-propanol, spermine and spermidine.

The term "alkanolamine" means an organic amine comprising a primary, secondary or tertiary amine function, and one or more linear or branched Ci to Cs alkyl groups bearing one or more hydroxyl radicals.

Alkanolamines chosen from monoalkanolamines, dialkanolamines or trialkanolamines comprising from one to three identical or different Ci to C4 hydroxyalkyl radicals are in particular suitable for performing the invention.

Among the compounds of this type, mention may be made of monoethanolamine (MEA), diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Ν,Ν-dimethylethanolamine, 2-amino-2-methyl-l-propanol, triisopropanolamine, 2-amino-2-methyl-l,3-propanediol, 3-amino-l,2-propanediol, 3-dimethylamino-l,2-propanediol and tris(hydroxymethyl)aminomethane.

More particularly, the amino acids that may be used are of natural or synthetic origin, in their L, D or racemic form, and comprise at least one acid function chosen more particularly from carboxylic acid, sulfonic acid, phosphonic acid and phosphoric acid functions. The amino acids may be in neutral or ionic form.

As amino acids that may be used in the composition according to the present invention, mention may be made especially of aspartic acid, glutamic acid, alanine, arginine, ornithine, citrulline, asparagine, carnitine, cysteine, glutamine, glycine, histidine, lysine, isoleucine, leucine, methionine, N-phenylalanine, proline, serine, taurine, threonine, tryptophan, tyrosine and valine.

Advantageously, the amino acids are basic amino acids comprising an additional amine function optionally included in a ring or in a ureido function.

Such basic amino acids are preferably chosen from those corresponding to formula (Q) below, and also the salts thereof

R-CH2-CH(NH2)-C(0)-OH (Q)

in which R represents a group chosen from imidazolyl, preferably imidazolyl-4-yl; aminopropyl; aminoethyl; -(CH2)2N(H)-C(0)-NH2; and -(CH2)2-N(H)-C(NH)-NH2.

The compounds corresponding to formula (Q) are histidine, lysine, arginine, ornithine and citrulline.

The organic amine may also be chosen from organic amines of heterocyclic type. Besides histidine that has already been mentioned in the amino acids, mention may in particular be made of pyridine, piperidine, imidazole, triazole, tetrazole and benzimidazole.

The organic amine may also be chosen from amino acid dipeptides. As amino acid dipeptides that may be used in the present invention, mention may be made especially of carnosine, anserine and balenine.

The organic amine may also be chosen from compounds comprising a guanidine function. As amines of this type that may be used in the present invention, besides arginine, which has already been mentioned as an amino acid, mention may be made especially of creatine, creatinine, 1,1-dimethylguanidine, 1,1-diethylguanidine, glycocyamine, metformin, agmatine, n-amidinoalanine, 3-guanidinopropionic acid, 4-guanidinobutyric acid and 2-([amino(imino)methyl]amino)ethane- 1 -sulfonic acid.

Hybrid compounds that may be mentioned include the salts of the amines mentioned previously with acids such as carbonic acid or hydrochloric acid.

Guanidine carbonate or monoethanolamine hydrochloride may be used in particular.

Preferably, the organic amine(s) present in the dye composition according to the invention are chosen from alkanolamines, and amino acids in neutral or ionic form, in particular basic amino acids, and preferably corresponding to those of formula (Q) and guanidine carbonate.

More preferentially, the organic amine(s) present in the dye composition according to the invention are chosen from monoethanolamine (MEA), diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, 2-amino-2-methyl- 1 -propanol, 2-amino-2-methyl- 1 ,3-propanediol, tris(hydroxymethylamino)methane, arginine, lysine, guanidine carbonate, and mixtures thereof.

The organic amine(s) are preferably present in an amount ranging from 0.1% to 20% by weight, preferably from 1% to 10% by weight and better still from 2%> to 8%) by weight, relative to the total weight of the dye composition.

As indicated previously, the dye composition according to the invention comprises one or more dyes chosen from oxidation dyes and direct dyes.

The oxidation dyes that may be used in the present invention are generally chosen from oxidation bases, optionally combined with one or more couplers.

The oxidation bases may be chosen especially from para-phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols, ortho-aminophenols and heterocyclic bases, and the addition salts thereof.

Among the para-phenylenediamines, examples that may be mentioned include para-phenylenediamine, para-tolylenediamine, 2-chloro-para-phenylenediamine, 2,3-dimethyl-para-phenylenediamine, 2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine, 2,5-dimethyl-para-phenylenediamine, Ν,Ν-dimethyl-para-phenylenediamine, N,N-diethyl-para-phenylenediamine, Ν,Ν-dipropyl-para-phenylenediamine, 4-amino-N,N-diethyl-3-methylaniline, N,N-bis( -hydroxyethyl)-para-phenylenediamine, 4-N,N-bis( -hydroxyethyl)amino-2-methylaniline, 4-N,N-bis( -hydroxyethyl)amino-2-chloroaniline, 2- -hydroxyethyl-para-phenylenediamine, 2-fluoro-para-phenylenediamine, 2-isopropyl-para-phenylenediamine, N-( -hydroxypropyl)-para-phenylenediamine, 2-hydroxymethyl-para-phenylenediamine, 2-hydroxypropyl- 1,3-bis(N-hydroxyethyl)-p-phenylenediamine, N,N-dimethyl-3-methyl-para-phenylenediamine, N-ethyl-N-( -hydroxyethyl)-para-phenylenediamine, Ν-(β,γ-dihydroxypropyl)-para-phenylenediamine, N-(4'-aminophenyl)-para-phenylenediamine, N-phenyl-para-phenylenediamine, 2- -hydroxyethyloxy-para-phenylenediamine, 2- -acetylaminoethyloxy-para-phenylenediamine, Ν-(β-methoxyethyl)-para-phenylenediamine, 4-aminophenylpyrrolidine, 2-thienyl-para-phenylenediamine, 2- -hydroxyethylamino-5-aminotoluene and 3 -hydroxy- 1-(4'-aminophenyl)pyrrolidine, and the addition salts thereof with an acid.

Among the para-phenylenediamines mentioned above, para-phenylenediamine, para-tolylenediamine, N,N-bis( -hydroxyethyl)-para-phenylenediamine, 2- -hydroxyethyl-para-phenylenediamine, 2-isopropyl-para-phenylenediamine, 2-hydroxypropyl- 1 ,3-(bis-N-hydroxyethyl)-p-phenylenediamine, 2- -hydroxyethyloxy-para-phenylenediamine, 2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine, 2,3-dimethyl-para-phenylenediamine, N,N-bis( -hydroxyethyl)-para-phenylenediamine, 2-chloro-para-phenylenediamine and 2-β-acetylaminoethyloxy-para-phenylenediamine, and the addition salts thereof with an acid, are particularly preferred.

Among the bis(phenyl)alkylenediamines, examples that may be mentioned include N,N'-bis( -hydroxyethyl)-N,N'-bis(4'-aminophenyl)- 1 ,3-diaminopropanol, N,N'-bis( -hydroxyethyl)-N,N'-bis(4'-aminophenyl)ethylenediamine, N,N'-bis(4-aminophenyl)tetramethylenediamine, N,N'-bis( -hydroxyethyl)-N,N'-bis(4-aminophenyl)tetramethylenediamine, N,N'-bis(4-methylaminophenyl)tetramethylenediamine, N,N'-bis(ethyl)-N,N'-bis(4'-amino-3'-methylphenyl)ethylenediamine, 1 ,8-bis(2,5-diaminophenoxy)-3,6-dioxaoctane and the addition salts thereof.

Among the para-aminophenols, examples that may be mentioned include para-aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol, 4-amino-3-chlorophenol, 4-amino-3-hydroxymethylphenol, 4-amino-2-methylphenol, 4-amino-2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol, 4-amino-2-aminomethylphenol, 4-amino-2-( -hydroxyethyl-aminomethyl)phenol and 4-amino-2-fluorophenol, and the addition salts thereof with an acid.

Among the ortho-aminophenols, examples that may be mentioned include 2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol and 5-acetamido-2-aminophenol, and the addition salts thereof.

Among the heterocyclic bases, examples that may be mentioned include pyridine derivatives, pyrimidine derivatives and pyrazole derivatives.

Among the pyridine derivatives that may be mentioned are the compounds described, for example, in patents GB 1 026 978 and GB 1 153 196, for instance 2,5-diaminopyridine, 2-(4-methoxyphenyl)amino-3-aminopyridine and 3,4-diaminopyridine, and the addition salts thereof.

Other pyridine oxidation bases that are useful in the present invention are the 3-aminopyrazolo[l,5-a]pyridine oxidation bases or the addition salts thereof described, for example, in patent application FR 2 801 308. Examples that may be mentioned include pyrazolo[l,5-a]pyrid-3-ylamine, 2-acetylaminopyrazolo[l,5-a]pyrid-3-ylamine, 2-(morpholin-4-yl)pyrazolo[l ,5-a]pyrid-3-ylamine, 3-aminopyrazo lo [ 1 ,5 -a]pyridine-2-carboxylic acid, 2-methoxypyrazolo [ 1 ,5 -a]pyrid-3 -ylamine, (3-aminopyrazolo[ 1 ,5-a]pyrid-7-yl)methanol, 2-(3-aminopyrazolo[ 1 ,5-

a]pyrid-5-yl)ethanol, 2-(3-aminopyrazolo[l,5-a]pyrid-7-yl)ethanol, (3-aminopyrazolo[l,5-a]pyrid-2-yl)methanol, 3,6-diaminopyrazolo[l,5-a]pyridine, 3,4-diaminopyrazolo[l,5-a]pyridine, pyrazolo[l,5-a]pyridine-3,7-diamine, 7-(morpholin- 4- yl)pyrazolo[l,5-a]pyrid-3-ylamine, pyrazolo[l,5-a]pyridine-3,5-diamine, 5-(morpholin-4-yl)pyrazo lo [ 1 ,5-a]pyrid-3 -ylamine, 2- [(3 -aminopyrazo lo [ 1 ,5 -ajpyrid- 5 -yl)(2-hydroxyethyl)amino] ethanol, 2- [(3 -aminopyrazo lo [ 1 ,5-a]pyrid-7-yl)(2-hydroxyethyl)amino]ethanol, 3-aminopyrazolo[l ,5-a]pyridin-5-ol, 3-aminopyrazo lo [ 1 ,5 -a]pyridin-4-ol, 3 -aminopyrazo lo [ 1 ,5 -a]pyridin-6-ol, 3 -aminopyrazo lo[ 1 ,5-a]pyridin-7-ol, 2-(2-hydroxyethoxy)-3-aminopyrazolo[ 1 ,5-ajpyridine, and 2-(4-methylpiperazinium-l-yl)-3-aminopyrazolo[l,5-a]pyridine chloride, and the addition salts thereof.

Among the pyrimidine derivatives that may be mentioned are the compounds described, for example, in the patents DE 2359399; JP 88-169571; JP

05- 63124; EP 0770375 or patent application WO 96/15765, such as 2,4,5,6-tetraaminopyrimidine, 4-hydroxy-2,5,6-triaminopyrimidine, 2-hydroxy-4,5,6-triaminopyrimidine, 2,4-dihydroxy-5 ,6-diaminopyrimidine, 2,5 ,6-triaminopyrimidine and the addition salts thereof and the tautomeric forms thereof, when a tautomeric equilibrium exists.

Among the pyrazole derivatives, mention may be made of the compounds described in patents DE 3843892 and DE 4133957 and patent applications WO 94/08969, WO 94/08970, FR-A-2 733 749 and DE 195 43 988, for instance 4,5-diamino- 1 -methylpyrazole, 4,5-diamino- 1 -( -hydroxyethyl)pyrazole, 3,4-diaminopyrazole, 4,5-diamino- 1 -(4'-chlorobenzyl)pyrazole, 4,5-diamino- 1,3-dimethylpyrazole, 4,5-diamino-3-methyl- 1 -phenylpyrazole, 4,5-diamino- 1 -methyl-3-phenylpyrazole, 4-amino-l,3-dimethyl-5-hydrazinopyrazole, l-benzyl-4,5-diamino-3-methylpyrazole, 4,5-diamino-3-tert-butyl- 1 -methylpyrazole, 4,5-diamino- 1 -tert-butyl-3 -methylpyrazole, 4,5-diamino- 1 -( -hydroxyethyl)-3-methylpyrazole, 4,5-diamino- 1 -ethyl-3 -methylpyrazole, 4,5-diamino- 1 -ethyl-3-(4'-methoxyphenyl)pyrazole, 4,5-diamino- 1 -ethyl-3-hydroxymethylpyrazole, 4,5-diamino-3-hydroxymethyl- 1 -methylpyrazole, 4,5-diamino-3-hydroxymethyl- 1 -isopropylpyrazole, 4,5-diamino-3-methyl- 1 -isopropylpyrazole, 4-amino-5-(2'-aminoethyl)amino-l,3-dimethylpyrazole, 3,4,5-triaminopyrazole, l-methyl-3,4,5-triaminopyrazole, 3,5-diamino-l-methyl-4-methylaminopyrazole and 3,5-diamino-4-

( -hydroxyethyl)amino-l-methylpyrazole, and the addition salts thereof. Use may also be made of 4,5-diamino- l-(P-methoxyethyl)pyrazole.

Use will preferably be made of a 4,5-diaminopyrazole and even more preferentially of 4,5-diamino- l-(P-hydroxyethyl)pyrazole and/or a salt thereof.

Pyrazole derivatives that may also be mentioned include diamino-N,N-dihydropyrazolopyrazolones and in particular those described in patent application FR-A-2 886 136, such as the following compounds and the addition salts thereof: 2,3-diamino-6,7-dihydro- lH,5H-pyrazolo[ 1 ,2-a]pyrazol- 1 -one, 2-amino-3-ethylamino-6,7-dihydro- 1 H,5H-pyrazolo [ 1 ,2-a]pyrazol- 1 -one, 2-amino-3-isopropylamino-6,7-dihydro- lH,5H-pyrazolo[ 1 ,2-a]pyrazol- 1 -one, 2-amino-3-(pyrrolidin- 1 -yl)-6,7-dihydro- lH,5H-pyrazolo[ 1 ,2-a]pyrazol- 1 -one, 4,5-diamino- 1 ,2-dimethyl- 1 ,2-dihydropyrazol-3-one, 4,5-diamino- 1 ,2-diethyl- 1 ,2-dihydropyrazol-3-one, 4,5-diamino- 1 ,2-di(2-hydroxyethyl)- 1 ,2-dihydropyrazol-3-one, 2-amino-3-(2-hydroxyethyl)amino-6,7-dihydro- lH,5H-pyrazolo[ 1 ,2-a]pyrazol- 1 -one, 2-amino-3-dimethylamino-6,7-dihydro- lH,5H-pyrazolo[ 1 ,2-a]pyrazol- 1 -one, 2,3-diamino-5,6,7,8-tetrahydro- lH,6H-pyridazino[ 1 ,2-a]pyrazol- 1 -one, 4-amino- 1 ,2-diethyl-5-(pyrrolidin- 1 -yl)- 1 ,2-dihydropyrazol-3-one, 4-amino-5-(3-dimethylaminopyrrolidin-1 -yl)- 1 ,2-diethyl- 1 ,2-dihydropyrazol-3-one, 2,3-diamino-6-hydroxy-6,7-dihydro-1 H,5H-pyrazolo [ 1 ,2-a]pyrazol- 1 -one.

Use will preferably be made of 2,3-diamino-6,7-dihydro-lH,5H-pyrazolo[l,2-a]pyrazol-l-one and/or a salt thereof.

Heterocyclic bases that will preferentially be used include 2-(2-hydroxyethoxy)-3-amino-pyrazolo[ 1 ,5-a]pyridine, 4,5-diamino- 1 -(β-hydroxyethyl)pyrazole and 2,3-diamino-6,7-dihydro-lH,5H-pyrazolo[l,2-a]pyrazol-1-one and/or a salt thereof.

The couplers that may be used in the present invention may be chosen from those conventionally used for the dyeing of keratin fibres.

Among these couplers, mention may be made especially of meta-phenylenediamines, meta-aminophenols, meta-diphenols, naphthalene-based couplers and heterocyclic couplers, and also the addition salts thereof.

Examples that may be mentioned include 1,3-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene, 4-chloro- 1 ,3-dihydroxybenzene, 1 -hydroxy-3-aminobenzene, 1 -methyl-2-hydroxy-4-P-hydroxyethylaminobenzene, 4-amino-2-hydroxytoluene, 5-amino-6-chloro-2-methylphenol, 2,4-diamino- 1 -(β-

hydroxyethyloxy)benzene, 2-amino-4-(P-hydroxyethylamino)- 1 -methoxybenzene, 1,3-diaminobenzene, l,3-bis(2,4-diaminophenoxy)propane, 3-ureidoaniline, 3-ureido- 1 -dimethylaminobenzene, sesamol, 1 -P-hydroxyethylamino-3 ,4-methylenedioxybenzene, a-naphthol, 2-methyl-l-naphthol, 6-hydroxyindole, 4-hydroxyindole, 4-hydroxy-N-methylindole, 2-amino-3-hydroxypyridine, 6-hydroxybenzomorpholine, 3,5-diamino-2,6-dimethoxypyridine, 1-Ν-(β-hydroxyethyl)amino-3 ,4-methylenedioxybenzene, 2,6-bis(P-hydroxyethylamino)toluene, 6-hydroxyindoline, 2,6-dihydroxy-4-methylpyridine, 1-H-3-methylpyrazol-5-one, l-phenyl-3-methylpyrazol-5-one, 2,6-dimethylpyrazolo[l,5-b]-l,2,4-triazole, 2,6-dimethyl[3,2-c]-l,2,4-triazole and 6-methylpyrazolo[l,5-a]benzimidazole, the addition salts thereof with an acid, and mixtures thereof.

In general, the addition salts of the oxidation bases and couplers that may be used in the context of the invention are in particular chosen from the addition salts with an acid, such as hydrochlorides, hydrobromides, sulfates, citrates, succinates, tartrates, lactates, tosylates, benzenesulfonates, phosphates and acetates.

The direct dye(s) may be chosen from synthetic direct dyes and natural direct dyes.

A direct dye is understood to be any dye which does not require the presence of a chemical oxidizing agent other than air for colouring.

A synthetic direct dye is understood to be any direct dye that does not exist in the natural state, including dyes obtained semi-synthetically.

Examples of suitable synthetic direct dyes that may be mentioned include azo, methine, carbonyl, azine, xanthene, nitro(hetero)aryl, tri(hetero)arylmethane, (metallo)porphyrin and phthalocyanine direct dyes, alone or as mixtures.

More particularly, the synthetic azo direct dyes include an -N=N- function in which the two nitrogen atoms are not simultaneously part of a ring. However, it is not excluded for one of the two nitrogen atoms of the sequence -N=N- to be part of a ring.

WE CLAIMS

1 . Dye composition comprising:

- 12-hydroxystearic acid,

- one or more organic amines, and

- one or more dyes chosen from oxidation dyes and direct dyes.

2. Dye composition according to Claim 1, characterized in that 12-hydroxystearic acid is present in an amount ranging from 0.1% to 40% by weight, better still from 1% to 30% by weight and even better still from 5% to 25% by weight relative to the total weight of the dye composition.

3. Dye composition according to Claim 1 or 2, characterized in that the organic amine(s) are chosen from alkanolamines, guanidine carbonate and mixtures thereof, and better still from monoethanolamine (MEA), diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine and guanidine carbonate, and mixtures thereof.

4. Dye composition according to any one of the preceding claims, characterized in that the organic amine(s) are present in an amount ranging from 0.1% to 20% by weight, preferably from 1% to 10% by weight and better still from 2%) to 8%) by weight, relative to the total weight of the dye composition.

5. Dye composition according to any one of the preceding claims, characterized in that the dye(s) are chosen from one or more oxidation dyes optionally combined with one or more direct dyes.

6. Dye composition according to any one of the preceding claims, characterized in that the dye(s) are chosen from para-phenylenediamines, para-aminophenols, pyrazole derivatives, meta-phenylenediamines, meta-aminophenols and meta-diphenols, and mixtures thereof.

7. Dye composition according to any one of the preceding claims, characterized in that the dye(s) represent from 0.0001% to 20% by weight, preferably from 0.001% to 15% by weight and better still from 0.01% to 10% by weight, relative to the total weight of the dye composition.

8. Dye composition according to any one of the preceding claims, characterized in that it comprises an amount of water ranging from 20% to 95% by weight, preferably from 40%> to 90%> by weight and better still from 55% to 85% by weight, relative to the total weight thereof.

9. Dye composition according to any one of the preceding claims, characterized in that it comprises one or more alkaline agents other than organic amines, preferably chosen from aqueous ammonia, sodium or potassium hydroxide, sodium or potassium carbonate, sodium or potassium bicarbonate, and mixtures thereof.

10. Dye composition according to Claim 9, characterized in that the alkaline agent(s) other than organic amines are present in an amount ranging from 0.01% to 30% by weight, preferably from 0.1% to 20% by weight and better still from 1% to 10% by weight relative to the total weight of the dye composition.

1 1 . Process for preparing the cosmetic composition according to any one of the preceding claims, comprising:

the mixing of 12-hydroxystearic acid, one or more organic amines and one or more dyes,

optionally heating for 1 to 10 minutes at a temperature ranging from 60 to 70°C, or for 30 minutes to 2 hours, at a temperature ranging from 20°C to 40°C, with or without stirring, preferably with gentle stirring, and

cooling of the mixture, preferably without stirring, to room temperature (18- 25°C).

12. Ready-to-use composition resulting from the extemporaneous mixing of a dye composition (A) according to any one of Claims 1 to 10 and of an oxidizing composition (B).

13. Ready-to-use composition according to Claim 12, characterized in that the oxidizing composition (B) comprises one or more oxidizing agents, preferably hydrogen peroxide, in particular in an amount ranging from 0.1% to 20% by weight, preferably from 0.5% to 15% by weight and better still from 2% to 12% by weight relative to the total weight of the oxidizing composition (B).

14. Multi-compartment device, or kit for dyeing keratin fibres, comprising at least two compartments:

- a first compartment containing a dye composition (A) according to any one of Claims 1 to 10; and

- a second compartment containing an oxidizing composition (B) as defined in Claim 12 or 13.

15. Process for dyeing keratin fibres, in particular human keratin fibres such as the hair, which consists in applying to said fibres a dye composition according to any one of Claims 1 to 10.

16. Process for dyeing keratin fibres, in particular human keratin fibres such as the hair, which consists in applying to said fibres a ready-to-use composition according to Claim 12 or 13.