Hair dyeing process, free of chemical oxidizing agent, using a titanium salt and a particular dye

The present invention relates to i) a process for the dyeing in one or more steps of keratin fibres, using one or more compositions comprising a) one or more titanium salts and b) optionally one or more particular carboxylic acids and c) one or more dyes as defined below, it being understood that the dyeing process does not use any chemical oxidizing agent and that a), b) and c) are applied to said fibres together or separately; ii) a composition free of chemical oxidizing agent, comprising ingredients a), b) and c); iii) use of the ingredients a), b) and c) for dyeing keratin fibres, free of chemical oxidizing agent.

It is known practice to dye keratin fibres and in particular human hair with dye compositions containing direct dyes. The standard dyes that are used are, in particular, dyes of the nitrobenzene, anthraquinone, nitropyridine, azo, xanthene, acridine, azine or triarylmethane type, or natural dyes.

These dyes may be nonionic, anionic, cationic or amphoteric. These dyes are coloured or colouring molecules that have affinity for keratin fibres. These compositions containing one or more direct dyes are applied to keratin fibres for a time necessary to obtain the desired colouring, and are then rinsed out. The colourings that result therefrom are particularly chromatic colourings but are, however, only 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 light, washing or perspiration.

Progress remains to be made in this field in order to afford powerful, resistant dyeing results that respect the nature of the hair using compositions containing dyes that are especially natural.

In the field of dyeing using natural extracts such as ortho-diphenols (ODPs), it is also known practice to dye keratin materials such as the hair or the skin using ODPs in the presence of a metal salt, especially of manganese (Mn) and/or zinc (Zn). In particular, patent applications FR 2 814 943, FR 2 814 945, FR 2 814 946 and FR 2 814 947 propose compositions for dyeing the skin or keratin fibres, comprising a dye precursor that contains at least one ortho-diphenol, Mn and/or Zn oxides and salts, alkaline agents of hydrogen carbonate type in a particular Mn, Zn/hydrogen carbonate ratio and optionally an enzyme. According to these documents, it is possible to obtain colourings on keratin materials with atmospheric oxygen or any oxygen-generating system.

However, the colourings obtained using ODPs are not strong enough or intense enough, and/or are not very persistent, especially in the case of hair fibres.

It is known practice to use metals at acidic pH for dyeing keratin fibres in amounts similar to those employed for dyes using a mordanting process, which consists in preparing the fibres before performing the dyeing operation in order to obtain persistent shades (Ullmann's Encyclopaedia "Metal and Dyes", 2005 § 5.1 , page 8). However, this process generally has the drawback of not always respecting the cosmetic nature of the keratin fibre.

Other documents describe the use of ODPs in combination with Mn and Zn salts and other metal salts, including titanium salts, and a chemical oxidizing agent (FR 297 673, WO2011/086284, WO2011/086282 and FR 2 951 374). Nevertheless, improvements should be further made, especially in terms of persistence of the colour with regard to shampooing and to sweat.

In addition, it is very difficult to build up the colour of natural dyes such as ODPs in the absence of a chemical oxidizing agent.

Moreover, it is known practice to use synthetic azo anionic dyes comprising a 1 ,8- dihydroxynaphthalene-3,5-disulfonate group with a Ti(IV) counterion (WO 00/38631). It is also known practice to use N-substituted 5,6-dihydroxyindole derivatives for dyeing keratin fibres in the presence of metal salts such as Cu, Fe, Ag, Mn or Zn in the presence of a chemical oxidizing agent (EP 0 335 477). However, these dyes do not always give satisfactory colourings especially in terms of chromaticity, intensity, homogeneity of the colour between the root and the end and/or resistance in particular to shampoo washing.

There is thus a real need to develop dyeing processes that make it possible to obtain sufficiently powerful and/or persistent colourings using direct dyes and/or self-oxidizing dyes, in particular natural dyes, especially ODPs, in particular from natural extracts that are rich in ODPs, which are less aggressive to keratin fibres, or which require smaller amounts of dyes, even in the absence of a chemical oxidizing agent. More particularly, there is a need to obtain colourings that satisfactorily withstand external agents (light, bad weather, shampooing or sweat), which are persistent and homogeneous, i.e. showing little dyeing selectivity between the root and the end, while at the same time remaining strong and/or chromatic. In addition, it is necessary, in order to obtain satisfactory colouring performance, for the product to be stable and to have suitable working qualities. This (these) aim(s) are achieved by the present invention, one subject of which is a process for dyeing keratin fibres, in particular human keratin fibres such as the hair, in which said fibres are treated, in one or more steps, with one or more cosmetic compositions containing:

a) one or more titanium salts: in particular, the titanium atom of said salt(s) is of oxidation state 2, 3 or 4, denoted Ti(ll), Ti(lll) or Ti(IV), preferably Ti(IV);

b) optionally one or more carboxylic acid(s) of formula (I) below, or a salt thereof: in which formula (I):

- A represents a monovalent group when n has the value 0 or a polyvalent group when n is greater than or equal to 1 , which group is saturated or unsaturated, cyclic or non-cyclic, aromatic or non-aromatic and hydrocarbon-based comprising from 1 to 50 carbon atoms, which is optionally interrupted with one or more heteroatoms and/or optionally substituted, in particular with one or more hydroxyl and/or amino groups; preferably, A represents a monovalent (d-C ₆ )alkyl group or a polyvalent (CrC ₆ )alkylene group optionally substituted with one or more hydroxyl and/or amino groups;

- n represents an integer between 0 and 10 inclusive; preferably, n is between 0 and 5, such as between 0 and 2; and

c) one or more dyes chosen from cationic, anionic or neutral natural dyes or synthetic direct dyes and self-oxidizing dyes, in particular natural dyes that are more particularly neutral, preferably chosen from ortho-diphenols;

it being understood that:

- the process does not use any chemical oxidizing agent, and

- ingredients a), b) and c) may be applied together or separately; preferably, a) and b) are together;

- when a), b) and c) are present in the same composition, then c) is other than an azo anionic direct dye comprising a 1 ,8-dihydroxynaphthalene-3,5-disulfonate group.

Another object of the invention is a process for dyeing keratin fibres, in particular human keratin fibres such as the hair, in which said fibres are treated, in one or more steps, with at least one cosmetic composition containing:

a) at least one titanium salt: in particular, the titanium atom of said salt(s) is of oxidation state 2, 3 or 4, denoted Ti(ll), Ti(lll) or Ti(IV), preferably Ti(IV);

b) optionally at least one carboxylic acid of formula (I) below, or a salt thereof;

in which formula (I):

- A represents a monovalent group when n has the value zero or a polyvalent group when n is greater than or equal to 1 , which group is saturated or unsaturated, cyclic or non-cyclic, aromatic or non-aromatic and hydrocarbon- based comprising from 1 to 50 carbon atoms, which is optionally interrupted with one or more heteroatoms and/or optionally substituted, in particular with one or more hydroxyl and/or amino groups; preferably, A represents a monovalent (d- C ₆ )alkyl group or a polyvalent (CrC ₆ )alkylene group optionally substituted with one or more hydroxyl and/or amino groups;

- n represents an integer between 0 and 10 inclusive; preferably, n is between 0 and 5, such as between 0 and 2; and

c) one or more dyes chosen from cationic, anionic or neutral synthetic direct dyes;

it being understood that:

- the process does not use any chemical oxidizing agent;

- the composition containing the titanium salt(s) a) has a pH of less than 7 and preferably of less than 5, in particular is at a pH between 0 and 4 inclusive, more particularly between 0.5 and 3.5, preferably between 1 and 3; and

- ingredients a), b) and c) may be applied together or separately; preferably, a) and b) are together;

- when a), b) and c) are present in the same composition, then c) is other than an azo anionic direct dye comprising a 1 ,8-dihydroxynaphthalene-3,5-disulfonate group. Another object of the invention is a process for dyeing keratin fibres, in particular human keratin fibres such as the hair, in which said fibres are treated, in one or more steps, with at least one cosmetic composition containing:

a) at least one titanium salt: in particular, the titanium atom of said salt(s) is of oxidation state 2, 3 or 4, denoted Ti(ll), Ti(lll) or Ti(IV), preferably Ti(IV);

b) optionally at least one carboxylic acid of formula (I) below, or a salt thereof;

in which formula (I):

- A represents a monovalent group when n has the value zero or a polyvalent group when n is greater than or equal to 1 , which group is saturated or unsaturated, cyclic or non-cyclic, aromatic or non-aromatic and hydrocarbon- based comprising from 1 to 50 carbon atoms, which is optionally interrupted with one or more heteroatoms and/or optionally substituted, in particular with one or more hydroxyl and/or amino groups; preferably, A represents a monovalent (C C ₆ )alkyl group or a polyvalent (CrC ₆ )alkylene group optionally substituted with one or more hydroxyl and/or amino groups;

- n represents an integer between 0 and 10 inclusive; preferably, n is between 0 and 5, such as between 0 and 2; and

c) one or more dyes chosen from cationic, anionic or neutral natural dyes, in particular from natural dyes that are more particularly neutral, preferably chosen from orthodiphenols;

it being understood that:

- the process does not use any chemical oxidizing agent; and

- ingredients a), b) and c) may be applied together or separately; preferably, a) and b) are together;

- when a), b) and c) are present in the same composition, then c) is other than an azo anionic direct dye comprising a 1 ,8-dihydroxynaphthalene-3,5-disulfonate group The term "chemical oxidizing agent" means an oxidizing agent other than atmospheric oxygen.

Another subject of the invention is a composition comprising ingredients a), b) and c) free of chemical oxidizing agent.

Another subject of the invention is the use of ingredients a), b) and c) for dyeing keratin fibres in the absence of a chemical oxidizing agent.

The process according to the invention and the composition of the invention have the advantage of dyeing human keratin fibres, with persistent dyeing results. In particular, the dyeing process according to the invention can produce colourings that are resistant to washing, perspiration and light without impairing the fibres. The colour homogeneity between the root and the end of the fibres is particularly good. Furthermore, the dyeing process used can induce very satisfactory "build-up" and/or strength of the colouring. In addition, the fact that no chemical oxidizing agent is used makes it possible to preserve the integrity of the keratin fibres.

Other subjects, characteristics, aspects and advantages of the present invention will emerge even more clearly on reading the description and the examples that follow. a) titanium salt(s):

The dyeing process according to the invention uses at least one composition comprising one or more titanium salts. This (these) salts may be organic or inorganic titanium salts.

For the purposes of the present invention, the term "organic titanium salt means the salts per se resulting from the action of at least one organic acid on Ti which may be of oxidation state 1 , 2, 3 or 4, preferably of oxidation state 4, denoted Ti(IV).

The term "organic acid' means an acid, i.e. a compound that is capable of releasing a cation or proton H ⁺ or H ₃ 0 ⁺ , in aqueous medium, which comprises at least one optionally unsaturated, linear or branched Ci-C ₂₀ hydrocarbon-based chain, or a (hetero)cycloalkyl or (hetero)aryl group and at least one acid chemical function being chosen in particular from carboxyl COOH, sulfuric S0 ₃ H, S0 ₂ H, and phosphoric P0 ₃ H ₂ , P0 ₄ H ₂ . In particular, the organic acid(s) for forming the organic titanium salt(s) of the invention are chosen from the carboxylic acid(s) of formula (I) as defined previously and are preferably a- hydroxy acids such as lactic acid, glycolic acid, tartaric acid or citric acid.

Preferentially, the organic titanium salt derived from the action of one or more organic acids as defined previously, preferably carboxylic acids of formula (I) as defined previously, is an optionally charged (in particular negatively charged) complex, which is complexed with one or more carboxylate groups of carboxylic acids.

Preferentially, the organic titanium salt(s) a) of the invention are chosen from those of formula (l-A) below:

in which formula (l-A):

• A is identical to that of formula (I)

• n, n' and n", which may be identical or different, are equal to 1 , 2, 3 or 4 and n' + n" =

• M and M ₂ , which may be identical or different, represent a cationic counterion chosen in particular from cations of an alkali metal such as Na or K or of an alkaline-earth metal such as Ca or an organic cation such as ammonium, preferably ammonium or a hydrogen atom;

• TiYn- denotes Ti(OH)n _" , or Ti(0) _{n /2} , or Ti(OH) _m1 (0) _m2 with mi+m ₂ = n".

Preferentially, the radical A of the compound (l-A) as defined previously represents a monovalent (CrC ₆ )alkyl or polyvalent (CrC ₆ )alkylene group optionally substituted with one or more hydroxyl groups or one or more amino groups, preferably with one or more hydroxyl groups, and n represents an integer between 0 and 5, such as between 0 and 2, inclusive; in particular, the carboxylic acid(s) used to form the organic titanium salt(s) of the invention are chosen from a-hydroxy acids and a-amino acids; preferentially, the acid is chosen from citric acid, lactic acid, malic acid, tartaric acid, glycolic acid and serine, more preferentially chosen from lactic acid and glycolic acid.

Preferentially, the organic titanium salt(s) a) of the invention are chosen from those of formula (l-B) below:

in which formula (l-B):

• L' and L", which may be identical or different, represent a divalent (hetero)arylene, (CrC ₆ )alkylene or (C ₂ -C ₆ )alkenylene group, said alkylene and arylene groups being optionally substituted with one or more atoms or groups chosen from halo, (d- C ₄ )alkyl, hydroxyl, thiol and (di)(Ci-C ₄ )(alkyl)amino, carboxyl, and/or optionally interrupted with one or more heteroatoms such as oxygen;

preferably, L' and L" are identical and represent a methylene or ethylene group optionally substituted with a (CrC ₄ )alkyl group;

• X' and X", which may be identical or different, represent a heteroatom such as oxygen, sulfur or amino R ^c -N with R ^c representing a hydrogen atom or a (CrC ₄ )alkyl group; preferably, X' and X" are identical and represent an oxygen atom;

• Y and Y', which may be identical or different, are as defined for X' and X"; preferably, Y and Y are identical and represent an oxygen atom;

• R ^a and R ^b , which may be identical or different, represent a hydrogen atom or a (C C ₆ )alkyl, (C ₂ -C ₆ )alkenyl or (hetero)aryl group; particularly, R ^a and R ^b are identical and represent a hydrogen atom or a (Ci-C ₄ )alkyl group, preferably hydrogen;

• M ⁺ , which may be identical or different, represent a cationic counterion such as a cation of an alkali metal (Na or K) or of an alkaline-earth metal (Ca) or an organic cation such as ammonium, preferably ammonium.

Preferably, the organic titanium salt(s) a) of the dyeing process are chosen from dihydroxybis(lactato)titanium(IV) salts such as those having the following formula:

For the purposes of the present invention, the term "inorganic titanium salt means the salts per se derived from the action of an inorganic acid on Ti.

The term "inorganic acid" means an acid which does not comprise carbon atoms, apart from carbonic acid.

According to a particular embodiment of the invention, the titanium salt(s) a) are inorganic. They are particularly chosen from titanium halides, titanium sulfates and titanium phosphates. Preferably, the inorganic titanium salts are Ti(ll), Ti(lll) or Ti(IV) salts, more particularly Ti(lll) or Ti(IV) salts, even more preferentially Ti(IV) salts.

According to a preferred embodiment of the invention, the titanium salt(s) a) are organic titanium salts, and better still organic Ti(IV) salts. According to an advantageous embodiment of the invention, the organic Ti salt consists of a Ti(IV) atom and of 2 to 3 molar equivalents of at least one carboxylic acid of formula (I).

The titanium salt(s) a) are present in at least one cosmetic composition in a content preferably ranging from 0.001% to 20% by weight relative to the total weight of the composition in which they are present.

In particular, the organic titanium salt(s) and the inorganic titanium salt(s) according to the invention are soluble in water in a proportion of at least 0.0001 g/l and better still at least 1 g/l. b) one or more carboxylic acids

According to a particular embodiment of the invention, the dyeing process uses at least one composition comprising one or more carboxylic acids.

The term "carboxylic acid' means a compound comprising at least one carboxylic acid -C(0)-OH group, preferably of formula (I) as defined previously, preferably comprising between 1 and 4 carboxylic acid groups, such as 1 or 2; or chosen from: i) (d-C ₁₀ )alkyl- [C(0)-OH] _n and ii) het-[C(0)-OH] _n , with n an integer between 1 and 4, preferably between 1 and 2, inclusive, and het representing a heterocyclic group, such as pyrrolidone, it being possible for the alkyl or het group to be optionally substituted with one or more groups chosen in particular from OH and (di)(Ci-C ₆ )(alkyl)amino.

According to an advantageous variant, the dyeing process also uses b) one or more carboxylic acids of formula (I) as defined previously.

More preferentially, the carboxylic acid(s) b) are different from the carboxylic acids complexed to the Ti salts, preferably glycolic acid, citric acid, lactic acid or a salt thereof.

In particular, the carboxylic acid(s) b) are preferably different from the carboxylic acids complexed to the Ti salts, when the Ti salt is an organic salt derived from the action of one or more carboxylic acids as defined previously. For example, if the carboxylic acid complexed to the titanium salt a) is lactic acid or the carboxylate salt thereof (lactate), the second acid b) is other than lactic acid or lactate, and may be, for example, glycolic acid.

The salts of the acids of formula (I) may be salts of organic or mineral bases or basifying agents d) as defined below. Preferably, the salts are sodium, ammonia or potassium salts or salts of organic amines such as alkanolamines.

The acids of formula (I) or the salts thereof are present in the composition comprising them, preferably with the titanium salt(s) as defined previously, in a content preferably ranging from 0.1% to 20% by weight, relative to the total weight of said composition. c) dve(s)

In accordance with the present invention, the process of the invention uses at least one composition comprising c) one or more dyes chosen from cationic, anionic, neutral, synthetic or natural direct dyes and self-oxidizing dyes, in particular natural dyes, preferably ortho-diphenols or ODPs. c1) According to one embodiment of the invention, the dye(s) are chosen from natural dyes.

The term "natural dyes" or "dyes of natural origin" means dyes derived from natural materials (plant, mineral or animal origin), for instance extracts, ground material and decoctions, which have a greater or smaller concentration of dyes.

Included among the natural dyes according to the invention are compounds that may be present in nature and that are reproduced by chemical (semi)synthesis.

The natural dyes may be chosen especially from spinulosin, orceins, polyphenols or ortho-diphenols (also known as ODPs in the rest of the description) and all extracts rich in ODPs, curcumin, indole derivatives such as isatin or indole-2,3-dione, indigoids including indigo, phthalocyanines and porphyrins in particular complexed to a metal, glycosyl or non-glycosyl iridoids, chromene dyes, anthraquinone and naphthoquinone dyes such as lawsone or henna, juglone, spinulosin, chromene or chroman dyes, such as neoflavanols and neoflavanones, flavanols; and anthocyanidols. Use may also be made of extracts or decoctions containing these natural dyes and especially plant extracts or poultices containing said dyes.

The dye(s) of natural origin according to the invention may or may not be salified. They may also be in aglycone form (without bonded sugar) or in the form of glycosylated compounds. The term "glycosyl radicaf means a radical derived from a monosaccharide or polysaccharide.

According to a particularly preferred embodiment of the invention, the dye(s) are chosen from ortho-diphenol(s): ODP(s) and polyphenols.

The term "ODP(s)" means one or more compounds comprising one or more aromatic rings, at least one of which is a benzene ring substituted with at least two hydroxyl (OH) groups borne by two adjacent carbon atoms of said benzene group which is present in the structure of the ortho-diphenol(s).

The aromatic ring is more particularly a fused aryl or fused heteroaromatic ring, i.e. optionally comprising one or more heteroatoms, such as benzene, naphthalene, tetrahydronaphthalene, indane, indene, anthracene, phenanthrene, indole, isoindole, indoline, isoindoline, benzofuran, dihydrobenzofuran, chroman, isochroman, chromene, isochromene, quinoline, tetrahydroquinoline and isoquinoline, said aromatic ring comprising at least two hydroxyl groups borne by two adjacent carbon atoms of the aromatic ring. Preferentially, the aromatic ring of the ortho-diphenol derivatives according to the invention is a benzene ring.

The term "fused ring" means that at least two saturated or unsaturated and heterocyclic or non-heterocyclic rings have a shared bond, i.e. at least one ring is placed side-by-side with another ring.

More particularly, the dye(s) of the invention represent an ODP of formula (II), or an oligomer, tautomer, optical isomer or geometrical isomer thereof, and also salts or solvates thereof, such as hydrates:

in which formula (II):

■ R ¹ to R ⁴ , which may be identical or different, represent: i) a hydrogen atom, ii) a halogen atom, or a group chosen from iii) hydroxyl, iv) carboxyl, v) (C C ₂₀ )alkyl carboxylate or (CrC ₂₀ )alkoxycarbonyl, vi) optionally substituted amino, vii) optionally substituted linear or branched (Ci-C ₂₀ )alkyl, viii) optionally substituted linear or branched (C ₂ -C ₂ o)alkenyl, ix) optionally substituted cycloalkyl, x) (Ci-C ₂₀ )alkoxy, xi) (Ci-C ₂₀ )alkoxy(Ci-C ₂₀ )alkyl, xii) (CrC ₂₀ )alkoxyaryl, xiii) aryl which may optionally be substituted, xiv) aryl, xv) substituted aryl, xvi) heterocyclic, which is saturated or unsaturated, optionally bearing a cationic or anionic charge and which is optionally substituted and/or optionally fused with an aromatic ring, preferably a benzene ring, said aromatic ring optionally being substituted, in particular with one or more hydroxyl or glycosyloxy groups, xvii) a radical containing one or more silicon atoms;

or two of the substituents borne by two adjacent carbon atoms R ¹ - R ² , R ² - R ³ or R ³ - R ⁴ form, together with the carbon atoms bearing them, a saturated or unsaturated and aromatic or non-aromatic ring optionally containing one or more heteroatoms and optionally fused with one or more saturated or unsaturated rings optionally containing one or more heteroatoms. In particular, the compound of formula (II) comprises from one to four rings.

A particular embodiment of the invention relates to one or more ODPs of formula (II), two adjacent substituents R ¹ - R ² , R ² - R ³ or R ³ - R ⁴ of which cannot form, with the carbon atoms that bear them, a pyrrolyl radical. According to a variant, R ² and R ³ form a pyrrolyl or pyrrolidinyl radical fused to the benzene ring bearing the two hydroxyls.

For the purposes of the present invention and unless otherwise indicated:

- the saturated or unsaturated and optionally fused rings may also be optionally substituted;

- the "alkyf radicals are saturated, linear or branched, generally C C- ₂₀ , particularly C C ₁₀ , hydrocarbon-based radicals, preferably Ci-C ₆ alkyl radicals, such as methyl, ethyl, propyl, butyl, pentyl and hexyl;

- the "alkenyf radicals are unsaturated and linear or branched C ₂ -C ₂ o hydrocarbon-based radicals; preferably comprising at least one double bond, such as ethylene, propylene, butylene, pentylene, 2-methylpropylene and decylene;

- the "aryf radicals are monocyclic or fused or non-fused polycyclic carbon-based radicals preferentially comprising from 6 to 30 carbon atoms, at least one ring of which is aromatic; preferentially, the aryl radical is chosen from phenyl, biphenyl, naphthyl, indenyl, anthracenyl and tetrahydronaphthyl;

- the "alkoxy" radicals are alkyl-oxy radicals with alkyl as defined previously, preferably CrC ₁₀ alkyl, such as methoxy, ethoxy, propoxy and butoxy;

- the "alkoxyalkyf radicals are (C ₁ -C ₂ o)alkoxy(C ₁ -C ₂ o)alkyl radicals, such as methoxymethyl, ethoxymethyl, methoxyethyl, ethoxyethyl, etc.;

- the "cycloalkyr radicals are C ₄ -C ₈ cycloalkyl radicals, preferably cyclopentyl and cyclohexyl radicals; the cycloalkyl radicals may be substituted cycloalkyl radicals, in particular substituted with alkyl, alkoxy, carboxylic acid, hydroxyl, amine and ketone groups;

- the "alkyf or "alkenyf radicals, when they are "optionally substituted', may be substituted with at least one atom or group borne by at least one carbon atom chosen from: i) halogen; ii) hydroxyl; iii) (Ci-C ₂ )alkoxy; iv) (CrCi ₀ )alkoxycarbonyl; v) (poly)hydroxy(C ₂ -C ₄ )alkoxy; vi) amino; vii) 5- or 6-membered heterocycloalkyl; viii) optionally cationic 5- or 6-membered heteroaryl, preferably imidazolium, optionally substituted with a (CrC ₄ )alkyl radical, preferably methyl; ix) amino substituted with one or two identical or different CrC ₆ alkyl radicals optionally bearing at least: a) one hydroxyl group, b) one amino group optionally substituted with one or two optionally substituted (d-C ₃ )alkyl radicals, it being possible for said alkyl radicals to form, with the nitrogen atom to which they are attached, a saturated or unsaturated and optionally substituted 5- to 7-membered heterocycle optionally comprising at least one other nitrogen or non-nitrogen heteroatom, c) a quaternary ammonium group - N ⁺ R'R"R"', M ^" for which R', R" and R"\ which may be identical or different, represent a hydrogen atom or a CrC ₄ alkyl group; and M ^" represents the counterion of the corresponding organic acid, mineral acid or halide, d) or one optionally cationic 5- or 6- membered heteroaryl radical, preferentially imidazolium, optionally substituted with a (CrC ₄ )alkyl radical, preferably methyl; x) acylamino (-N(R)-C(0)-R') in which the radical R is a hydrogen atom or a (CrC ₄ )alkyl radical optionally bearing at least one hydroxyl group and the radical R' is a C C ₂ alkyl radical; a carbamoyl ((R) ₂ N-C(0)-) radical in which the radical Rs, which may be identical or different, represent a hydrogen atom or a (Ci-C ₄ )alkyl radical optionally bearing at least one hydroxyl group; xi) alkylsulfonylamino (R'-S(0) ₂ -N(R)-) in which the radical R represents a hydrogen atom or a (Ci-C ₄ )alkyl radical optionally bearing at least one hydroxyl group and the radical R' represents a (d-d)alkyl radical or a phenyl radical; xii) aminosulfonyl ((R) ₂ N-S(0) ₂ -) in which the radical Rs, which may be identical or different, represent a hydrogen atom or a (d-C ₄ )alkyl radical optionally bearing at least one group chosen from a) hydroxyl, b) carboxyl -C(0)-OH in the acid or salified (preferably salified with an alkali metal or a substituted or unsubstituted ammonium) form; xiii) cyano; xiv) nitro; xv) carboxyl or glycosylcarbonyl; xvi) phenylcarbonyloxy optionally substituted with one or more hydroxyl groups; xvii) glycosyloxy; and phenyl group optionally substituted with one or more hydroxyl groups;

- the "aryf or "heterocyclic" radicals or the aryl or heterocyclic part of the radicals, when they are "optionally substituted", may be substituted with at least one atom or group borne by at least one carbon atom chosen from:

i) (Ci-Cio)alkyl, preferably d-C ₈ alkyl, optionally substituted with one or more radicals chosen from the following radicals: hydroxyl, (d-C ₂ )alkoxy, (poly)hydroxy(C ₂ - C ₄ )alkoxy, acylamino, amino substituted with two identical or different d-C ₄ alkyl radicals optionally bearing at least one hydroxyl group or it being possible for the two radicals to form, with the nitrogen atom to which they are attached, a saturated or unsaturated and optionally substituted 5- to 7-membered, preferably 5- or 6- membered, heterocycle optionally comprising another nitrogen or non-nitrogen heteroatom; ii) halogen; iii) hydroxyl; iv) d-C ₂ alkoxy; v) d-C ₁₀ alkoxycarbonyl; vi) (poly)hydroxy(C ₂ -C ₄ )alkoxy; vii) amino; viii) 5- or 6-membered heterocycloalkyl; ix) optionally cationic 5- or 6-membered heteroaryl, preferably imidazolium, optionally substituted with a (CrC ₄ )alkyl radical, preferably methyl; x) amino substituted with one or two identical or different CrC ₆ alkyl radicals optionally bearing at least: a) one hydroxyl group, b) one amino group optionally substituted with one or two optionally substituted Ci-C ₃ alkyl radicals, it being possible for said alkyl radicals to form, with the nitrogen atom to which they are attached, a saturated or unsaturated and optionally substituted 5- to 7-membered heterocycle optionally comprising at least one other nitrogen or non-nitrogen heteroatom, c) one quaternary ammonium group -N ⁺ R'R"R"', M ^" for which R', R" and R"\ which may be identical or different, represent a hydrogen atom or a Ci-C ₄ alkyl group; and M ^" represents the counterion of the corresponding organic acid, mineral acid or halide, d) one optionally cationic 5- or 6-membered heteroaryl radical, preferably imidazolium, optionally substituted with a (d-C ₄ )alkyl radical, preferentially methyl; xi) acylamino (-N(R)-C(0)-R') in which the radical R is a hydrogen atom or a CrC ₄ alkyl radical optionally bearing at least one hydroxyl group and the radical R' is a CrC ₂ alkyl radical; xii) carbamoyl ((R) ₂ N-C(0)-) in which the radical Rs, which may be identical or different, represent a hydrogen atom or a Ci-C ₄ alkyl radical optionally bearing at least one hydroxyl group; xiii) alkylsulfonylamino (R'S(0) ₂ -N(R)-) in which the radical R represents a hydrogen atom or a CrC ₄ alkyl radical optionally bearing at least one hydroxyl group and the radical R' represents a CrC ₄ alkyl radical or a phenyl radical; xiv) aminosulfonyl ((R) ₂ N-S(0) ₂ -) in which the radicals R, which may be identical or different, represent a hydrogen atom or a Ci-C ₄ alkyl radical optionally bearing at least one hydroxyl group; xv) carboxyl in the acid or salified (preferably salified with an alkali metal or a substituted or unsubstituted ammonium) form; xvi) cyano; xvii) nitro; xviii) polyhaloalkyl, preferentially trifluoromethyl; xix) a glycosylcarbonyl; xx) a phenylcarbonyloxy group optionally substituted with one or more hydroxyl groups; xxi) a glycosyloxy group; and xxii) a phenyl group optionally substituted with one or more hydroxyl groups;

for the purposes of the present invention, the term "glycosyf radical means a radical derived from a mono- or polysaccharide;

the radicals "containing one or more silicon atoms" are preferably polydimethylsiloxane, polydiphenylsiloxane, polydimethylphenylsiloxane or stearoxy dimethicone radicals; the "heterocyclic" radicals are radicals comprising, in at least one ring, one or more heteroatoms chosen in particular from O, N and S, preferably O or N, optionally substituted in particular with one or more alkyl, alkoxy, carboxyl, hydroxyl, amine or ketone groups. These rings may comprise one or more oxo groups on the carbon atoms of the heterocycle; mention may in particular be made, among the heterocyclic radicals that may be used, of furyl, pyranyl, pyrrolyl, imidazolyl, pyrazolyl, pyridyl or thienyl groups; even more preferably, the heterocyclic groups are fused groups, such as benzofuryl, chromenyl, xanthenyl, indolyl, isoindolyl, quinolyl, isoquinolyl, chromanyl, isochromanyl, indolinyl, isoindolinyl, coumarinyl or isocoumarinyl groups, it being possible for these groups to be substituted, in particular with one or more OH groups.

The salts of the dyes of the invention may be salts of acids or of bases. The acids may be mineral or organic. Preferably, the acid is hydrochloric acid, which results in chlorides. According to another preferred embodiment of the invention, the dye composition used in the process for dyeing keratin fibres comprises, as dye, one or more natural dyes.

More particularly, the dye(s) of the invention according to a) are chosen from: 1 ) anthocyanidins such as cyanidin, delphinidin, petunidin; 2) anthocyanines or anthocyans such as myrtillin; 3) ortho-hydroxybenzoates, for example gallic acid salts; 4) flavones such as luteolin; 5) hydroxystilbenes, for example tetrahydroxy-3,3',4,5'-stilbene, optionally in oxyl (for example glucosyl) form; 6) curcumin; 7) indole derivatives such as isatin or indole-2,3-dione and indigo, preferably isatin; 8) phtalocyanines and porphyrins in particular complexed to a metal, especially chlorophyllin and more particularly that complexed with copper or magnesium, preferably copper chlorophyllin; 9) glycosyl or non-glycosyl iridoids such as (seco)iridoid-glycoside or non-glycosyl (seco)iridoid; 10) 3,4-dihydroxyphenylalanine and derivatives thereof; 1 1 ) 2,3-dihydroxyphenylalanine and derivatives thereof; 12) 4,5-dihydroxyphenylalanine and derivatives thereof; 13) dihydroxycinnamates such as caffeic acid and chlorogenic acid; 14) ortho- polyhydroxycoumarins; 15) ortho-polyhydroxyisocoumarins; 16) ortho- polyhydroxycoumarones; 17) ortho-polyhydroxyisocoumarones; 18) ortho- polyhydroxychalcones; 19) ortho-polyhydroxychromones; 20) anthraquinones; 21 ) naphthoquinones or benzoquinones, in particular juglone and lawsone; 22) hydroxyxanthones; 23) 1 ,2-dihydroxybenzene and derivatives thereof; 24) 1 ,2,4- trihydroxybenzene and derivatives thereof; 25) 1 ,2,3-trihydroxybenzene and derivatives thereof; 26) 2,4,5-trihydroxytoluene and derivatives thereof; 27) proanthocyanidins and especially proanthocyanidins A1 , A2, B1 , B2, B3 and C1 ; 28) chroman and chromene compounds such as neoflavanols and neoflavanones chosen especially from haematoxylin, haematein, brazilin and brazilein; preferentially brazilin; 29) flavanols such as catechin and epicatechin gallate; 30) flavonols such as quercetin; 31 ) proathocyanines; 32) tannic acid; 33) ellagic acid; 34) indigoids, mixtures of these compounds, and extracts containing them; more preferentially, the dye(s) c) are chosen from the families 2), 3), 6), 7), 8), 9), 20), 21 ), 22), 28), 29), 30), 32), 34), and also a mixture thereof, and extracts containing them.

According to a particular embodiment of the invention, the natural dyes of the invention are chosen from anthraquinone dyes, chosen from those of formulae (A1) and (A2) below:

(A1) (A2) and also the tautomeric and/or mesomeric forms thereof, the stereoisomers thereof, the addition salts thereof with a cosmetically acceptable acid or base, and the solvates thereof such as hydrates;

^■ R ¹ and R ⁸ , which may be identical or different, represent a hydrogen atom or a hydroxyl group or alkyl group such as methyl;

^■ R ² represents a hydrogen atom or a hydroxyl group, carboxyl group -C(0)OH or carboxylate group -C(0)0 ^" , CTwith Q ⁺ representing an alkali metal or alkaline-earth metal such as potassium or calcium;

^■ R ³ represents i) a hydrogen atom, ii) a hydroxyl group or iii) an optionally substituted aryl group, preferably a phenyl group optionally substituted with one or more groups chosen from a) hydroxyl, b) amino, c) (d-C ₆ )alkyl optionally substituted with one or more groups chosen from hydroxyl, carboxyl and (C C ₄ )alkylcarbonylamino;

^■ R ⁴ represents a hydrogen atom or a hydroxyl group;

^■ R ⁵ represents a hydrogen atom, or a hydroxyl group, carboxyl group or carboxylate group -C(0)0 ^" , CTwith Q ⁺ as defined previously;

^■ R ⁶ represents a hydrogen atom, a hydroxyl group, -O ^" , Q ⁺ with Q ⁺ as defined previously, carboxyl group or carboxylate group -C(0)0 ^" , Q ⁺ with Q ⁺ as defined previously;

^■ R ⁷ represents a hydrogen atom or a glycosyl radical, preferably glucose;

^■ M represents a metal, preferably from column IIIA of the Periodic Table of the Elements, such as aluminium; and

^■ G represents a hydroxyl group, a water molecule or a ligand such as alkoxy or (di)(alkyl)amino.

Preferentially, the dyes of the invention are of formula (A1) and in particular, taken together or separately:

^■ R ¹ represents a hydroxyl or (CrC ₄ )alkyl group;

^■ R ² , R ⁴ and R ⁸ , which may be identical or different, represent a hydrogen atom or a hydroxyl group;

^■ R ³ represents a hydrogen atom, a hydroxyl group or a phenyl group optionally substituted with one or more groups chosen from hydroxyl, carboxyl and (d-

C ₄ )alkylcarbonylamino such as:

with Y representing a group chosen from: -CH(NH ₂ )- C(0)OH, -CH ₂ -OH, -NH-C(0)-CH ₃ ; and VWthe point of attachment to the rest of the molecule.

^■ R ⁵ and R ⁶ , which may be identical or different, represent a hydrogen atom or a hydroxyl group, carboxyl group -C(0)OH or carboxylate group -C(0)0 ^" , CTwith Q ⁺ representing an alkali metal or alkaline-earth metal such as potassium or calcium; and

^■ R ⁷ represents a hydrogen atom.

According to one embodiment, the dye(s) of the invention are of formula (A2) and in particular, taken together or separately:

^■ R ¹ represents a (CrC ₄ )alkyl group;

■ R ² represents a carboxyl group or carboxylate group -C(0)0 ^" , Q ⁺ with Q ⁺ representing an alkali metal or alkaline-earth metal such as potassium or calcium;

^■ R ³ and R ⁸ represent a hydroxyl group;

^■ R ⁴ represents a hydrogen atom or a hydroxyl group, preferably hydrogen;

^■ R ⁶ represents a hydroxyl group, -O ^" , Q ⁺ with Q ⁺ as defined previously; and ■ R ⁷ represents a glycosyl radical such as glucose.

Preferentially, the dye(s) of the invention are chosen from the following anthraquinones and extracts containing them:

• Garance (Rubia tinctorum or Rubia cordifolia);

· 1 ,3-dihydroxyanthraquinone (purpuroxanthin);

• carminic acid and its non-glycosyl form;

• kermesic acid;

• carmine (Crimson lake, cochineal, natural red 4, C.I. 75470 or E120), and the aluminium salt of carminic acid;

^• 1 ,4-dihydroxyanthraquinone (quinizarine);

^• 1 ,2,4-trihydroxyanthraquinone (purpurin, veratin, Smoke Brown G, C.I. 1037, C.I.

58205, C.I. 75410, C.I. Natural Red 16, C.I. Natural Red 8);

· 1 ,2-dihydroxyanthraquinone (alizarin);

^• laccaic acid A, B, C or D; and

^• anthragallol or 1 ,2,3-trihydroxyanthraquinone.

More preferentially, the anthraquinones and extracts containing them are chosen from garance; kermesic acid; carmine, and the aluminium salt of carminic acid; carminic acid and its non-glycosyl form; 1 ,2,4-trihydroxyanthraquinone or purpurin; laccaic acid A, B, C or D; and anthragallol or 1 ,2,3-trihydroxyanthraquinone.

According to another preferred mode of the invention, the natural dye(s) are chosen from naphthoquinones, in particular juglone and lawsone. In particular those derived from leaves of shrubs of the genus Lawsonia from the family of Lythraceae, which is based on the principle of dyeing with the active agent lawsone: 2-hydroxy-1 ,4-naphthoquinone from henna. Lawsone [83-72-7] (CI Natural Orange 6; CI 75420), also known as isojuglone, may be found in henna shrubs (Lawsonia alba, Lawsonia inermis). Preferably, the henna is in powder form. The henna powder may be screened to obtain particles with upper limit sizes corresponding to the orifices or mesh sizes of the screen particularly between 35 and 80 mesh (US). According to one particular mode of the invention, the size of the henna powder particles is fine. According to the invention, a particle size of less than or equal to 500 μηι is more particularly intended. Preferentially, the powder consists of fine particles with sizes inclusively between 50 and 300 μηι and more particularly between 10 and 200 μηι. It is understood that said henna particles preferentially have a moisture content of between 0 and 10% by weight, relative to the total weight of the powders.

According to another particular embodiment, the dye(s) are chosen from indole derivatives such as isatin or indole-2,3-dione and indigo, preferably isatin. In particular, the dye(s) are derived from the plants Isatis tinctoria, Calanthe discolor or Couroupita guianensis.

According to a preferred embodiment of the invention, at least one cosmetic composition comprises at least one natural dye c) chosen from naphtoquinone dyes, such as lawsone or henna, juglone, spinulosin, preferably lawsone or henna, and/or from indole derivatives such as isatin or indole-2,3-dione, indigoids including indigo, preferably indigo. According to another preferred embodiment of the invention, at least one cosmetic composition comprises at least two natural dyes c), wherein preferably at least one dye is chosen from naphtoquinone dyes, such as lawsone or henna, juglone, spinulosin, preferably lawsone or henna, and/or from indole derivatives such as isatin or indole-2,3- dione, indigoids including indigo, preferably indigo ; or mixture thereof, better still said at least two natural dyes c) are chosen from naphtoquinone dyes such as lawsone or henna, juglone, spinulosin, preferably lawsone or henna, and indole derivatives such as isatin or indole-2,3-dione, indigoids including indigo, preferably indigo.

According to a particular embodiment, the dye(s) are curcumine or curcumin. This is a compound that is naturally present in curry, which is a polyphenol whose chemical name is (1 £,6£)-1 ,7-bis(4-hydroxy-3-methoxyphenyl)-1 ,6-heptadiene-3,5-dione, and also the tautomeric forms thereof.

According to a particular embodiment, the dye(s) of the invention are chosen from natural porphyrins and phthalocyanines, in particular those complexed with a metal, especially chlorophyllin and in particular that complexed with copper or magnesium, preferably copper chlorophyllin.

According to one embodiment, the dye(s) are chosen from glycosyl or non-glycosyl iridoids. In particular, the dye(s) of the invention are chosen from (seco)iridoid-glycoside or non-glycosyl (seco)iridoid (also known as aglycone), extracted from plants such as Rubiaceae, Euphorbiaceae, Valerianaceae, Cornaceae, Gentianaceae, Caprifoliaceae, Oleaceae, Ericaceae, Loganiaceae, etc., preferably Rubiaceae. More particularly, the dye(s) of the invention are derived from extracts of the following plants: Veronica persica; Genipa americana; Apodytes dimidiata; Randia canthioides; Tarenna attenuata and preferably Genipa americana. According to a particular embodiment of the invention, the dye(s) are chosen from chromene or chroman dyes. According to the invention, the term "chromene or chroman dyes" mean dyes which comprise in their structure at least one bicycle of formula (B) below:

(B)

the endocyclic bond representing a carbon-carbon single bond or else a carbon- carbon double bond, as illustrated by formula (B1) below, denoting the chromene family, and formula (B2) below, denoting the chroman family:

(B1) (B2).

More particularly, the dye(s) of the invention are of formula (B) and are preferentially chosen from neoflavonols and neoflavanones, particularly chosen from the dyes of the following formulae:

> formula (III), comprising, in i formula (B2):

and also the tautomeric and/or mesomeric forms thereof, the stereoisomers thereof, the addition salts thereof with a cosmetically acceptable acid or base, and the solvates thereof such as hydrates;

in which formula (III):

^■ represents a carbon-carbon single bond or a carbon-carbon double bond, the sequence of these bonds denoting two carbon-carbon single bonds and two carbon-carbon double bonds, said bonds being conjugated,

^■ X represents a group:

//

HO— c or 0=C

^■ R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ , which may be identical or different, represent a hydrogen atom, a hydroxyl group, an optionally substituted alkyl group, an optionally substituted alkoxy group or an optionally substituted acyloxy group; and

formula (IV), comprising, in its structure, the bicycle of formula (B1):

and also the tautomeric and/or mesomeric forms thereof, the stereoisomers thereof, the addition salts thereof with a cosmetically acceptable acid or base, and the hydrates thereof;

in which formula (IV):

^■ R _{11 ;} R ₁₂ , Ri ₃ , Ri ₆ , Rig and R ₂₀ , which may be identical or different, represent a hydrogen atom or a Ci-C ₄ alkyl radical, and

^■ Ri4, Ri5, Ri7 and R ₁₈ , which may be identical or different, represent a hydrogen atom, a hydroxyl radical or a Ci-C ₄ alkoxy radical.

As regards the dyes of formula (III) as defined previously, they may be found in two tautomeric forms denoted (Ilia) and (lllb):

The alkyl radicals mentioned in the preceding definitions of the substituents are saturated and linear or branched hydrocarbon-based radicals, generally C C- ₂₀ , particularly C1-C1 ₀ , preferably Ci-C ₆ , hydrocarbon-based radicals, such as methyl, ethyl, propyl, butyl, pentyl and hexyl.

The alkoxy radicals are alkyl-oxy radicals with the alkyl radicals as defined above and preferably the alkoxy radicals are CrC ₁₀ alkoxy radicals, such as methoxy, ethoxy, propoxy and butoxy.

The alkyl or alkoxy radicals, when they are substituted, may be substituted with at least one substituent borne by at least one carbon atom chosen from: i) a halogen atom or ii) a hydroxyl group; iii) a CrC ₂ alkoxy group; iv) a C1-C1 ₀ alkoxycarbonyl group; v) a (poly)hydroxy(C ₂ -C ₄ )alkoxy group; vi) an amino group; vii) a 5- or 6-membered heterocycloalkyl group; viii) an optionally cationic 5- or 6-membered heteroaryl group, preferably imidazolium, optionally substituted with a (CrC ₄ )alkyl radical, preferably methyl; ix) an amino radical substituted with one or two identical or different CrC ₆ alkyl radicals optionally bearing at least: a) one hydroxyl group, b) one amino group optionally substituted with one or two optionally substituted CrC ₃ alkyl radicals, it being possible for said alkyl radicals to form, with the nitrogen atom to which they are attached, a saturated or unsaturated and optionally substituted 5- to 7-membered heterocycle optionally comprising at least one other nitrogen or non-nitrogen heteroatom, c) one quaternary ammonium group -N ⁺ R'R"R"', M ^" for which R', R" and R"\ which may be identical or different, represent a hydrogen atom or a Ci-C ₄ alkyl group and M ^" represents the counterion of the corresponding organic acid, mineral acid or halide, d) or one optionally cationic 5- or 6-membered heteroaryl radical, preferably imidazolium, optionally substituted with a (d-C ₄ )alkyl radical, preferably methyl; x) an acylamino (-N(R)-C(0)-R') radical in which the radical R is a hydrogen atom or a CrC ₄ alkyl radical optionally bearing at least one hydroxyl group and the radical R' is a C C ₂ alkyl radical; xi) a carbamoyl ((R) ₂ N-C(0)-) radical in which the radical Rs, which may be identical or different, represent a hydrogen atom or a Ci-C ₄ alkyl radical optionally bearing at least one hydroxyl group; xii) an alkylsulfonylamino (R'-S(0) ₂ -N(R)-) radical in which the radical R represents a hydrogen atom or a CrC ₄ alkyl radical optionally bearing at least one hydroxyl group and the radical R' represents a C C ₄ alkyl radical or a phenyl radical; xiii) an aminosulfonyl ((R) ₂ N-S0 ₂ -) radical in which the radical Rs, which may be identical or different, represent a hydrogen atom or a Ci-C ₄ alkyl radical optionally bearing at least one hydroxyl group; xiv) a carboxyl radical in the acid or salified (preferably salified with an alkali metal or a substituted or unsubstituted ammonium) form; xv) a cyano group; xvi) a nitro group; xvii) a carboxyl or glycosylcarbonyl group; xviii) a phenylcarbonyloxy group optionally substituted with one or more hydroxyl groups; xix) a glycosyloxy group; and xx) a phenyl group optionally substituted with one or more hydroxyl groups.

Preferably, the alkyl or alkoxy radicals of formula (III) are unsubstituted.

According to a particular embodiment of the invention, the dye(s) of formula (III) comprise a radical R ₆ representing a hydroxyl group.

Another particular embodiment of the invention relates to the dye(s) of formula (III) for which the radical represents a hydrogen atom or a hydroxyl group.

More particularly, the dye(s) of the invention are of formula (III) and chosen from haematoxylin and, haematein and, brazilin and brazilein; preferentially brazilin:

Brazilein

Haematoxylin (Natural Black 1 Brazilin (Natural Red 24 - CAS 517-28-2) CAS 474-07-7).

Brazilein is a conjugated form of a chroman compound of formula (A2). The tautome illustrated above are found in the scheme below.

Brazilein

Among the dyes of the invention of haematoxylin/haematein and brazilin/brazilein type, examples that may be mentioned include haematoxylin (Natural Black 1 according to the INCI name) and brazilin (Natural Red 24 according to the INCI name), dyes of the indochroman family, which are commercially available. The latter dyes may exist in an oxidized form and may be obtained synthetically or by extraction from plants or vegetables known to be rich in these dyes.

The natural dye(s) of the invention may be used in the form of extracts. Use may be made of the following plant extracts (genus and species): Haematoxylon campechianum, extracted from oxidized logwood (Haematoxylon campechianum) brasiletto (Hematoxylum braziletto, rich in brazilin and protosappanin), Quebracho (Schinopsis lorentsii) Caesalpinia echinata, Caesalpinia sappan, Caesalpinia spinosa, and Caesalpina Brasiliensis.

The extracts are obtained by extracting various plant parts, for instance the roots, the wood, the bark or the leaves.

According to a particular embodiment of the invention, the dye(s) of natural origin are of formula (II) and are obtained from logwood, pernambuco wood, sappan wood and Brazil wood.

According to a particular embodiment of the invention, the dyes are of formula (IV), preferably those for which and R ₁₃ represent an alkyl radical, preferably methyl.

Preferably, R ₁₂ , Ri e, R19 and R ₂₀ denote, independently of each other, a hydrogen atom or an alkyl radical, preferably methyl.

Preferably, R ₁₄ and R ₁₇ denote, independently of each other, a hydrogen atom or an alkoxy radical, preferably methoxy.

Preferably, R ₁₈ and R ₁₅ denote, independently of each other, a hydrogen atom, a hydroxyl radical or an alkoxy radical, preferably methoxy.

A first particularly preferred family of dyes of natural origin of the invention that are suitable for use in the present invention is that of the dyes corresponding to formula (IV) above for which R ₁₂ , R15, Ri e, R17, R19 and R ₂₀ each represent a hydrogen atom. Rn and R ₁₃ each represent a methyl radical and R ₁₄ represents a methoxy radical.

Among the preferred dyes of the invention of this first family are those for which R ₁₈ represents a methoxy radical (santalin B) or a hydroxyl radical (santalin A).

A second particularly preferred family of dyes that are suitable for use in the present invention is that of the dyes corresponding to the formula (IV) above for which:

- R11 and Ri3 each represent a methyl radical,

- R ₁₇ represents a methoxy radical.

A preferred dye of this second family is that for which, in addition, R ₁₉ represents a methyl radical, R ₂₀ , R12, R14, Ris and R _{1 6} each represent a hydrogen atom and R ₁₅ represents a hydroxyl radical (santarubin A).

A second preferred dye of this second family is that for which R _{1 8} , R ₂₀ , R12, R14 and Ri e represent a hydrogen atom, R ₁₅ represents a methoxy radical and R ₁₉ represents a methyl radical (santarubin B).

A third family of preferred dyes of this second family is that for which R ₂₀ , R ₁₂ , Ri ₄ , R ₁₅ , R _{1 6} and R ₁₉ represent hydrogen and R ₁₈ represents a hydroxyl radical (santarubin C).

The advantageous dye of this second family is that for which R ₁₅ represents a methoxy radical, R ₁₈ and R ₁₄ represent a hydrogen atom and R ₂₀ , Ri ₂ , Ri ₆ and R ₁₉ represent a methyl radical (tetra-O-methylsantarubin).

The natural dye(s) of formula (IV) may be used in the form of extracts. Use may be made of plant extracts of red woods, bringing together generally the species of red woods from Asia and West Africa of the genus Pterocarpus and of the genus Baphia. These woods are, for example, Pterocarpus santalinus, Pterocarpus osun, Pterocarpus soyauxii, Pterocarpus erinaceus, Pterocarpus indicus or Baphia nitida. These woods may also be called padauk, sandalwood, narra wood, camwood or barwood. Thus, extracts that may be used, containing dyes of formula (IV), in the present invention may be obtained, for example, from red sandalwood (Pterocarpus santalinus) by aqueous basic extraction, such as the product sold under the trade name Santal Concentre SL 709C by the company COPIAA, or else by means of solvent extraction of sandalwood powder, such as the product sold under the trade name Santal Poudre SL PP by the same company COPIAA. Mention may also be made of the aqueous/alcoholic extract of powdered red sandalwood from the company Alban Muller.

Extracts also suitable for the present invention can be obtained from woods such as camwood (Baphia nitida) or also barwood (Pterocarpus soyauxii, Pterocarpus erinaceus): the latter is thus split up and then ground: a conventional alcoholic extraction or one by percolation is subsequently carried out on this ground material in order to collect a pulverulent extract particularly suitable for the implementation of the present invention.

The dye(s) of formulae (III) and (IV) of the invention may be salts of acids or bases that are cosmetically acceptable.

The acids may be mineral or organic. Preferably, the acid is hydrochloric acid, which results in chlorides.

The bases may be mineral or organic. In particular, the bases are alkali metal hydroxides such as sodium hydroxide which leads to sodium salts.

According to a particular embodiment of the invention, the dye(s) are chosen from dihydroxyflavonoids, preferably of formula (V) and also the organic or mineral acid or base salts thereof, optical isomers, geometrical isomers and tautomers thereof, and solvates thereof such as hydrates:

in which formula (V):

^• represents a single bond or a double bond;

^• R ¹ , R ² , R ³ , R ⁴ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ , which may be identical or different, represent a hydrogen or halogen atom or a group chosen from i) hydroxyl, ii) (CrC ₆ )alkyl, iii) (C C ₆ )alkoxy, iv) (CrC ₆ )alkylthio, v) carboxyl, vi) alkyl or alkoxycarbonyl carboxylate, vii) optionally substituted amino, viii) optionally substituted linear or branched alkenyl, ix) optionally substituted cycloalkyi, x) optionally substituted aryl, xi) a group containing one or more silicon atoms, xii) (di)((hydroxy)(C ₁ -C ₆ )alkyl)amino, xiii) glucosyl, xiv) R-Z-C(X)- Y- with R representing a hydrogen atom or a (CrC ₆ ) alkyl or aryl group that is optionally substituted, especially with at least one hydroxyl group, such as 3,4,5-trihydroxyphenyl; Y and Z, which may be identical or different, represent a bond or an oxygen or sulfur atom or a group -N(R')- with R' representing a hydrogen atom or a (CrC ₆ )alkyl group, Y also possibly representing a (d-C ₆ )alkylene group; X representing an oxygen or sulfur atom or N-R" with R" representing a hydrogen atom or a (CrC ₆ )alkyl group;

• R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ , which may be identical or different, represent a hydrogen atom or a group chosen from a hydroxyl group, a (CrC ₆ )alkyl group or a group R-Z-C(X)-Y- as defined previously,

• or alternatively the unit (V) constitutes the polymeric unit of a polyphenol which will be linked to the other units of said polyphenol via positions 4, 6 or 8 of the chroman ring, in which case R ¹ or R ³ and R ⁶ form a covalent bond with the other units of said polyphenol;

· or else R ⁵ with R ⁶ and/or R ⁷ with R ⁸ form, together with the carbon atom which bears them, an oxo group;

• or else R ⁸ and R ⁹ together form a bond;

it being understood that:

- when R ⁵ with R ⁶ and/or R ⁷ with R ⁸ together form an oxo group, or R ⁸ with R ⁹ together form a bond, then— represents a single bond;

- when— is a double bond between the oxygen atom and the carbon atom in position 2, then R ₉ is absent, and when— is a double bond between the carbon atoms in positions 3 and 4, then R ₅ and R ₇ are absent;

- when— borne by the oxygen atom is a double bond, then the compound of formula (V) is cationic and an organic or mineral anionic counterion such as a halide is associated therewith.

Preferably, at least two radicals of the compounds of formula (V) chosen from R _{1 ;} R ₂ , R ₃ , R ₄ , Rio, Rii, Ri ₂ , Ri3 and R ₁₄ , which are contiguous, represent a hydroxyl group.

Preferably, the group R-Z-C(X)-Y- of the compounds of formula (V) represents a 3,4,5- trihydroxyphenyl-1 -carbonyloxy (-O-gallate). Preferably, the radicals R _{1 ;} R ₂ , R ₃ , R ₄ , Rio, Rii, Ri ₂ , Ri3 and R ₁₄ are chosen from the hydrogen atom and hydroxyl, glycosyloxy and alkoxy groups.

According to a particular embodiment, the dye(s) c) of the invention are chosen from: i) the flavanols of formula (Va) which preferably comprise at least two ortho hydroxyl groups, such as catechin, extracted from pine bark, epicatechin gallate, and cocoa flavonols, especially epicatechin, flavonols, in particular flavan-3-ols from green tea, and oligomers and polymers thereof known as proanthocyanidols or fused tannins such as theaflavin, theaflavin 3'-0-gallate, theaflavin 3,3'-0-digallate, proanthocyanidins A1 , A2, B1 , B2, B3 and C1 such as profisetinidin and procyanidin, and mixtures of the preceding compounds.

Flavan-3-ols or flavanol: (Va) and also organic or mineral acid or base salts thereof, the optical isomers, geometrical isomers and tautomers thereof, and the solvates thereof such as hydrates;

in which formula (Va):

S R ⁷ , R ⁸ , which may be identical or different, represent a hydrogen atom or a group chosen from hydroxyl or (d-C ₆ )alkyl or a group R-Z-C(X)-Y- as defined previously, preferably O-gallate, it being understood that at least one of the two groups R ⁷ or R ⁸ represents a hydroxyl group or R-Z-C(X)-Y- as defined previously;

R ⁵ and R ⁶ , which may be identical or different, represent a hydrogen atom or a hydroxyl group or R ⁶ and R ⁸ form a bond or the unit (Va) constitutes the polymer unit that will be bonded to the other units via positions 4, 6 or 8, in which case R ¹ , or R ³ and R ⁶ form a bond; the radicals R\ R ² , R ³ , R ⁴ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ being as defined previously for formula (V);

among the proanthocyanidin compounds, examples that may be mentioned include profisetinidin and procyanidin, the formulae of which are represented;

- ii) the flavonols of formula (Vb) which comprise at least two ortho hydroxyl groups, such as quercetin, luteolin, myricetol or fisetin, and/or two meta hydroxyl groups, such as morin, heterosides thereof or methoxylated derivatives thereof such as rhamnetin (which preferably comprise at least two ortho hydroxyl groups):

Flavonol:

3-hydroxy-2-phenylchromen-4-one and also the organic or mineral acid or base salts thereof, the optical isomers, geometrical isomers and tautomers thereof, and the solvates thereof such as hydrates; in which formula (Vb) the radicals Ft ¹ , Ft ² , Ft ³ , Ft ⁴ , Ft ¹⁰ , Ft ¹¹ , Ft ¹² , Ft ¹³ and Ft ¹⁴ are as defined previously in formula (V);

- iii) the flavones of formula (Vc) which comprise at least two ortho hydroxyl groups, such as luteolin, and heterosides thereof such as luteolol 7-O-glucoside, baicalin and orientin.

Flavone:

2-phenylchromen-4-one

and also the organic or mineral acid or base salts thereof, the optical isomers, geometrical isomers and tautomers thereof, and the solvates thereof such as hydrates; in which formula (Vc) the radicals Ft ¹ , Ft ² , Ft ³ , Ft ⁴ , Ft ¹⁰ , Ft ¹¹ , Ft ¹² , Ft ¹³ and Ft ¹⁴ are as defined previously in formula (V);

- iv) the dihydroflavonols or dihydroxyflavanonols of formula (Vd) which comprise at least two ortho hydroxyl groups, such as dihydroquercetol, and heterosides thereof such as dihydroquercetol 3-O-rhamoside:

Dihydroflavonol or Flavanonol:

(Vd)

3-hydroxy-2,3-dihydro-2-phenylchromen-4-one and also the organic or mineral acid or base salts thereof, the optical isomers, geometrical isomers and tautomers thereof, and the solvates thereof such as hydrates; in which formula (Vd) the radicals Ft ¹ , Ft ² , Ft ³ , Ft ⁴ , Ft ¹⁰ , Ft ¹¹ , Ft ¹² , Ft ¹³ and Ft ¹⁴ are as defined previously in formula (V);

- v) the flavanones of formula (Ve) which comprise at least two ortho hydroxyl groups, such as eriodictyol;

Flavanone:

2,3-dihydro-2-phenylchromen-4-one

and also the organic or mineral acid or base salts thereof, the optical isomers, geometrical isomers and tautomers thereof, and the solvates thereof such as hydrates; in which formula (Ve) the radicals Ft ¹ , Ft ² , Ft ³ , Ft ⁴ , Ft ¹⁰ , Ft ¹¹ , Ft ¹² , Ft ¹³ and Ft ¹⁴ are as defined previously in formula (V);

- vi) the flavan-3,4-diols or leucoanthocyanidins of formula (Vf) which comprise at least two ortho hydroxyl groups, such as leucocyanidol (= procyanidol).

and also the organic or mineral acid or base salts thereof, the optical isomers, geometrical isomers and tautomers thereof, and the solvates thereof such as hydrates; in which formula (Vf) the radicals Ft ¹ , Ft ² , Ft ³ , Ft ⁴ , Ft ¹⁰ , Ft ¹¹ , Ft ¹² , Ft ¹³ and Ft ¹⁴ are as defined previously in formula (V);

- vii) the anthocyanidols (or anthocyanides, or anthocyanidins) of formula (Vg), which comprise at least two ortho hydroxyl groups, such as cyanidol, delphinidin, aurantinidin, luteolinidin, heterosides thereof, such as dihydroxyanthocyans (or dihydroxyanthocyanosides, or anthocyanins on the English model), oligomers and polymers thereof such as proanthocyanins, preferably anthocyanodols and especially from bilberry, and 3-deoxyanthocyanidins especially from sorghum;

Anthocyanidol: (Vg)

Flavylium cation

and also the organic or mineral acid or base salts thereof, the optical isomers, geometrical isomers and tautomers thereof, and the solvates thereof such as hydrates; in which formula (Vg) the radicals Ft ¹ , Ft ² , Ft ³ , Ft ⁴ , Ft ¹⁰ , Ft ¹¹ , Ft ¹² , Ft ¹³ and Ft ¹⁴ are as defined previously in formula (V); viii) the compounds of formula (a), or an oligomer thereof:

and also the organic or mineral acid or base salts thereof, the optical isomers, geometrical isomers and tautomers thereof, and the solvates thereof such as hydrates; in which formula (a):

R represents a hydrogen atom or a hydroxyl group;

R' represents a hydroxyl group or the phenoxy group below (α'):

Y represents a divalent, trivalent or tetravalent group chosen from (d-C ₆ )alkylene such as methylene; carbonyl -C(O)-, -CH=, >C<;

Ri, R ₂ and R ₃ , which may be identical or different, represent a hydrogen atom or a hydroxyl or (CrC ₆ )alkoxy group such as methoxy; R ₄ represents a hydrogen atom or a hydroxyl or -O-glycoside group; or alternatively the radicals R, Y and R' form, together with the carbon atoms that bear them, a heterocyclic group fused to rin elow:

(P) (Y) (γ') R ₅ represents a hydrogen atom or a hydroxyl or -O-glycoside group;

R ₆ to R ₁₀ , which may be identical or different, represent a hydrogen atom or a hydroxyl group, preferably R ₆ and R ₁₀ represent a hydrogen atom, R ₇ , R ₈ and R ₉ represent a hydrogen atom or a hydroxyl group;

Z rep

it being understood that the compound of formula (a) bears at least two hydroxyl groups ortho to a phenyl radical.

In a preferred variant, the dye(s) according to the invention are compounds of formula (a), and more particularly polyphenols such as tannic acid.

The dye(s) according to the invention may in particular be a mixture of proanthocyanidin derivatives such as profisetinidin and procyanidin and of compounds of formula (a), and more particularly polyphenols such as tannic acid.

Preferably, the dye(s) of the invention are derived from plant extracts. Use may also be made of mixtures of plant extracts.

The natural extracts of the dyes according to the invention may be in the form of powders or liquids. Preferably, the extracts are in powder form.

Preferentially, the natural dye(s) c) of the invention are chosen from:

❖ anthraquinones chosen from those of formulae (A1) and (A2) as defined previously; more preferentially, the anthraquinones and extracts containing them are chosen from: garance; or Rubia tinctorum or Rubia cordifolia; kermesic acid; carmine; the aluminium salt of carminic acid; carminic acid and its non-glycosyl form; 1 ,2,4- trihydroxyanthraquinone or purpurin; laccaic acid A, B, C or D; and anthragallol or 1 ,2,3-trihydroxyanthraquinone;

❖ naphthoquinones, in particular juglone and lawsone and particularly those derived from leaves of shrubs of the genus Lawsonia;

❖ neoflavanols or neoflavanones chosen from those of formulae (III) and (IV) as defined previously; more particularly chosen from haematoxylin and haematein, brazilin and brazilein; preferentially brazilin, the following plant extracts (genus and species): Haematoxylon campechianum, extracted from oxidized logwood (Haematoxylon campechianum) brasiletto (Hematoxylum braziletto, rich in brazilin and protosappanin), Quebracho (Schinopsis lorentsii) Caesalpinia echinata, Caesalpinia sappan, Caesalpinia spinosa, and Caesalpina Brasiliensis;

❖ glycosyl or non-glycosyl iridoids such as (seco)iridoid-glycoside or non-glycosyl (seco)iridoid extracted from plants such as Rubiaceae or Genipa americana;

❖ the flavanols of formula (Va) as defined previously;

preferably, the flavonols (Va) are chosen from catechin, extracted from pine bark, epicatechin gallate, and cocoa flavonols, especially epicatechin, flavan-3-ols from green tea, and oligomers thereof and mixtures thereof;

❖ the flavonols of formula (Vb) as defined previously, in particular the flavanols (Vb) comprising at least two ortho and/or meta groups, are preferably chosen from quercetin, luteolin and morin, and the heterosides thereof;

❖ the anthocyanidols of formula (Vg) as defined previously, preferably, the anthocyanidols (Vg) are chosen from those from bilberry and 3-deoxyanthocyanidins from sorghum;

❖ the compounds of formula (a), as defined previously, preferably tannic acid;

❖ indigoids such as indigo. In particular, the natural dye(s) of the invention are chosen from catechin, quercetin, brazilin, haematein, haematoxylin, chlorogenic acid, caffeic acid, gallic acid, catechol, gallic acid L-DOPA, pelargonidin, cyanidin, (-)-epicatechin, (-)-epigallocatechin, (-)- epigallocatechin 3-gallate (EGCG), (+)-catechin, isoquercetin, pomiferin, esculetin, 6,7- dihydroxy-3-(3-hydroxy-2,4-dimethoxyphenyl)coumarin, santalin AC, mangiferin, butein, maritimetin, sulfuretin, robtein, betanidin, pericampylinone A, theaflavin, proanthocyanidin A2, proanthocyanidin B2, proanthocyanidin C1 , procyanidins DP 4-8, tannic acid, purpurogallin, 5,6-dihydroxy-2-methyl-1 ,4-naphthoquinone, alizarin, wedelolactone, variegatic acid, gomphidic acid, xerocomic acid and carnosol, the indigoids especially of formula (XIII) as defined below, and natural extracts containing them.

Preferably, the dye(s) of the invention are chromene or chroman dyes and more preferentially the dye(s) of the invention are chosen from haematein, haematoxylin, brazilein, brazilin and santalin A.

The term " carboxylate" is understood to mean carboxylic acid salt.

When the dye(s) have D and L forms, both forms may be used in the compositions according to the invention, as may the racemates.

According to one embodiment, the natural dye(s) are derived from extracts of animals, bacteria, fungi, algae, plants and fruit, used in their entirety or partially. In particular regarding plants, the extracts are derived from fruit, including citrus fruit, from vegetables, from trees and from shrubs. Use may also be made of mixtures of these extracts, which are rich in natural dyes, especially in ODPs as defined previously.

Preferably, the natural dye(s) of the invention are derived from extracts of plants or of plant parts.

For the purposes of the invention, these extracts will be placed in the same category as ingredient c).

The extracts are obtained by extraction of various plant parts, for instance the root, the wood, the bark, the leaf, the flower, the fruit, the seed, the pod or the peel.

Among the plant extracts, mention may be made of extracts of tea leaves, in particular of Japanese green tea, and of rose.

Among the fruit extracts, mention may be made of extracts of apple, of grape (in particular of grape seed) or extracts of cocoa beans and/or pods.

Among the vegetable extracts, mention may be made of extracts of potato or of onion peel.

Among the extracts of tree wood, mention may be made of extracts of pine bark and extracts of logwood or extracts of quebracho wood.

Use may also be made of mixtures of plant extracts.

According to a particular embodiment of the invention, the ortho-diphenol derivative(s) are natural extracts, rich in ODPs. According to a preferred embodiment, the dye(s) of the invention are solely natural extracts.

Preferentially, the natural dye(s) according to the invention are chosen from catechin, quercetin, haematein, haematoxylin, brazilin, brazilein, gallic acid and tannic acid, and natural extracts containing them chosen from grape marc, pine bark, green tea, onion, cocoa bean, logwood, redwood and gall nut, sorghum (Sorghum vulgare), indigoids, in particular those of formula (XIII) as defined below, derived especially from indigo plant, and quebracho wood.

The natural extracts according to the invention may be in the form of powders or liquids. Preferably, the extracts of the invention are provided in the form of powders.

According to another embodiment of the invention, the dye(s) are chosen from synthetic direct dyes.

The synthetic direct dye(s) that may be used in the context of the invention are chosen from fluorescent or non-fluorescent, cationic, anionic or neutral direct dyes.

c2) According to a particular embodiment, the dye(s) c) are chosen from natural or synthetic, preferably synthetic, anionic direct dyes or dyes more commonly known as "acidic" direct dyes or "acid dyes" for their affinity with alkaline substances, on condition that when the dyeing process uses ingredients a), optionally b) and c) together on the keratin fibres, then the dye(s) c) do not comprise in their chemical structure a 1 ,8- dihydroxynaphthalene-3,5-disulfonate group.

The term "anionic direct dye" means any direct dye comprising in its structure at least one sulfonate S0 ₃ ^" group and/or at least one carboxylate group C(0)0 ^" and optionally one or more anionic groups G ^" with G , which may be identical or different, representing an anionic group chosen from alkoxide O ^" , thiolate S ^" , carboxylate and thiocarboxylate: C(Q)Q' ^~ , with Q and Q', which may be identical or different, representing an oxygen or sulfur atom; preferably, G ^" represents a carboxylate, i.e. Q and Q' represent an oxygen atom.

More particularly, the dye(s) c) of the invention are chosen from the direct dyes of formula (VI):

CoK- ⁾ m (Q ⁺ ) _n (VI)

^■ Col ^{( )} _m represents the anionic part of the anionic direct dye or "acid' dye comprising in its structure at least one sulfonate group and/or at least one carboxylate group and comprising m anionic charges:

■ m and n, which may be identical or different, represent an integer between 1 and 10 inclusive;

^■ Q ⁺ , which may be identical or different, represent an organic or mineral cationic counterion preferably chosen from alkali metal or alkaline-earth metal cations such as Na ⁺ or K ⁺ ;

on condition that when a), b) and c) are present in the same composition, then c) is other than an azo anionic direct dye comprising a 1 ,8-dihydroxynaphthalene-3,5-disulfonate group.

In formula (VI) of the invention, the radical Col ⁽ ½ represents the anionic part of the "acid dyes" or of the anionic direct dyes and preferentially Col ⁽ ½ comprises in its structure:

o at least one sulfonate group and at least one (hetero)aryl group, it being understood that at least one sulfonate group is directly connected to a (hetero)aryl group, preferentially aryl such as phenyl or benzo; and

o optionally one or more anionic groups G ^" as defined previously;

on condition that when a), b) and c) are present in the same composition, then c) is other than an azo anionic direct dye comprising a 1 ,8-dihydroxynaphthalene-3,5-disulfonate group.

According to another preferred embodiment of the invention, Col ^{( )} m comprises in its structure:

o at least one carboxylate group and

o at least one (hetero)aryl group, it being understood that at least one carboxylate group is directly connected to a (hetero)aryl group, preferentially aryl such as phenyl or benzo; and

o optionally one or more anionic groups G ^" as defined previously;

on condition that when a), b) and c) are present in the same composition, then c) is other than an azo anionic direct dye comprising a 1 ,8-dihydroxynaphthalene-3,5-disulfonate group.

According to yet another preferred embodiment of the invention, Col ^{( )} _m comprises in its structure:

o at least one carboxylate group, at least one sulfonate group and at least one (hetero)aryl group, it being understood that at least one sulfonate or carboxylate group is directly connected to a (hetero)aryl group, preferentially aryl such as phenyl or benzo; and

o optionally one or more anionic groups G ^" as defined previously;

on condition that when a), b) and c) are present in the same composition, then c) is other than an azo anionic direct dye comprising a 1 ,8-dihydroxynaphthalene-3,5-disulfonate group.

According to a particular embodiment of the invention, the dyes of formula (VI) are such that m is equal to n.

An advantageous variant of the invention concerns the dyes of formula (VI) for which m and n are equal to 1 , 2 or 3.

The preferred anionic dye(s) of formula (VI) of the invention are chosen from acidic nitro direct dyes, acidic azine dyes, acidic triarylmethane dyes, acidic indoamine dyes, acidic anthraquinone dyes, acidic indigoids and acidic natural dyes; each of these dyes having at least one sulfonate or carboxylate group bearing a cationic counterion as defined previously; preferentially alkali metal, alkaline-earth metal or ammonium sulfonate or carboxylate.

As dyes according to the invention, mention may be made of the dyes of formulae (VII), (VII'), (VIII), (VIII'), (IX), (ΙΧ'), (X), (Χ'), (XI), (XII), (XIII) and (XIV) below:

c2a) the diaryl anionic azo dyes of formula (VII) or (VII'):

which formulae (VII) and (VII'):

R ₇ , R ₈ , R ₉ , R ₁₀ , R' ₇ , R' ₈ , R' ₉ and R' ₁₀ , which may be identical or different, representing a hydrogen atom or a group chosen from: i) alkyl, ii) alkoxy, iii) alkylthio, iv) hydroxyl, v) mercapto, vi) nitro, vii) R°-C(X)-X'-, R°-X'-C(X)-, R°-X'- C(X)-X"- with R° representing a hydrogen atom or an alkyl or aryl group; X, X' and X", which may be identical or different, representing an oxygen or sulfur atom or NR with R representing a hydrogen atom or an alkyl group; viii) (0) ₂ S(0 ^~ )-, M ⁺ with M ⁺ as defined previously for M or representing a cationic counterion as defined previously; ix) (O)CO -, M ⁺ with M ⁺ as defined previously; x) R"-S(0) ₂ -, with R" representing a hydrogen atom, an alkyl group, an aryl, (di)(alkyl)amino or aryl(alkyl)amino group; preferentially a phenylamino or phenyl group; xi) R'"- S(0) ₂ -X'- with R'" representing an optionally substituted alkyl or aryl group, X' as defined previously; xii) (di)(alkyl)amino; xiii) aryl(alkyl)amino optionally substituted with one or more groups chosen from nitro; nitroso; (0) ₂ S(0 ^~ )-, M ⁺ and alkoxy with M ⁺ as defined previously; xiv) optionally substituted heteroaryl; preferentially a benzo thiazolyl group; xv) cycloalkyl; especially cyclohexyl, xvi) Ar-N=N- with Ar representing an optionally substituted aryl group; preferentially a phenyl optionally substituted with one or more alkyl groups, (0) ₂ S(0 , M ⁺ or phenylamino;

• or alternatively two contiguous groups R ₇ with R ₈ or R ₈ with R ₉ or R ₉ with R ₁₀ together form a fused benzo group A'; and R' ₇ with R' ₈ or R' ₈ with R' ₉ or R' ₉ with R'io together form a fused benzo group B'; with A' and B' optionally substituted with one or more groups chosen from i) nitro; ii) nitroso; iii) (0) ₂ S(0 ^~ )-, M ⁺ ; iv) hydroxyl; v) mercapto; vi) (di)(alkyl)amino; vii) R°-C(X)-X'-; viii) R°-X'-C(X)-; ix) R°- X'-C(X)-X"-; x) Ar-N=N- and xi) optionally substituted aryl(alkyl)amino; with M ⁺ , R°, X, X', X" and Ar as defined previously;

W represents a sigma bond σ, an oxygen or sulfur atom, or a divalent radical i) - NR- with R as defined previously, or ii) methylene -C(R _a )(Rb)- with R _a and R _b , which may be identical or different, representing a hydrogen atom or an aryl group, or alternatively R _a and R _b together form, with the carbon atom that bears them, a spiro cycloalkyl; preferentially, W represents a sulfur atom or R _a and R _b together form a cyclohexyl;

it being understood that:

- formulae (VII) and (VII') comprise at least one sulfonate (0) ₂ S(0 , Q ⁺ or carboxylate (0)C(0 , Q ⁺ radical on one of the rings A, A', B, B' or C; preferentially alkali metal, alkaline-earth metal or ammonium sulfonate or carboxylate; and

- when a), b) and c) are present in the same composition, then c) is other than an azo anionic direct dye comprising a 1 ,8-dihydroxynaphthalene-3,5-disulfonate group.

As examples of dyes of formula (VII), mention may be made of: Acid Red 1 , Acid Red 4, Acid Red 13, Acid Red 14, Acid Red 18, Acid Red 27, Acid Red 32, Acid Red 33, Acid Red 35, Acid Red 37, Acid Red 40, Acid Red 41 , Acid Red 42, Acid Red 44, Acid Red 68, Acid Red 73, Acid Red 135, Acid Red 138, Acid Red 184, Food Red 1 , Food Red 13, Acid Orange 6, Acid Orange 7, Acid Orange 10, Acid Orange 19, Acid Orange 20, Acid Orange 24, Acid Yellow 9, Acid Yellow 36, Acid Yellow 199, Food Yellow 3; Acid Violet 7, Acid Violet 14, Acid Blue 1 13, Acid Blue 117, Acid Black 1 , Acid Brown 4, Acid Brown 20, Acid Black 26, Acid Black 52, Food Black 1 , Food Black 2;

and as examples of dyes of formula (VII'), mention may be made of: Acid Red 11 1 , Acid Red 134, Acid Yellow 38;

c2b) the pyrazolone anionic azo dyes of formulae (VIII) and (VIII'):

in which formulae (VIII) and (VIII');

^• Rii, Ri ₂ and Ri ₃ , which may be identical or different, represent a hydrogen or halogen atom, an alkyl group or -(0) ₂ S(0 ^~ ), M ⁺ with M ⁺ as defined previously;

^• R ₁₄ represents a hydrogen atom, an alkyl group or a group -C(0)0-, IVT with M ⁺ as defined previously;

^• Ri ₅ represents a hydrogen atom;

Ri6 represents an oxo group, in which case R'i ₆ is absent, or alternatively Ri ₅ with Ri6 together form a double bond;

^• R ₁₇ and R ₁₈ , which may be identical or different, represent a hydrogen atom or a group chosen from:

(0) ₂ S(0 , M ⁺ with M ⁺ as defined previously;

Ar-0-S(0) ₂ - with Ar representing an optionally substituted aryl group, preferentially a phenyl optionally substituted with one or more alkyl groups;

^• Rig and R ₂₀ together form either a double bond, or a benzo group D', which is optionally substituted;

^• R' ₁₆ , R' ₁₉ and R' ₂₀ , which may be identical or different, represent a hydrogen atom or an alkyl or hydroxyl group;

^• R ₂ i represents a hydrogen atom or an alkyl or alkoxy group;

^• R _a and R _b , which may be identical or different, are as defined previously, preferentially R _a represents a hydrogen atom and R _b represents an aryl group;

^• m either a hydroxyl group or an oxo group;

^• represents a single bond when Y is an oxo group; and represents a double bond when Y represents a hydroxyl group;

it being understood that formulae (VIII) and (VIII') comprise at least one sulfonate group (0) ₂ S(0 , Q ⁺ on one of the rings D or E or formulae (VIII) and (VIII') comprise at least one carboxylate group (0)C(0 , Q ⁺ with Q ⁺ as defined previously; preferentially comprise at least one sulfonate group (0) ₂ S(0 , Q ⁺ on one of the rings D or E and more particularly sulfonate.

As examples of dyes of formula (VIII), mention may be made of: Acid Red 195, Acid Yellow 23, Acid Yellow 27, Acid Yellow 76, and as examples of dyes of formula (VIM'), mention may be made of Acid Yellow 17; c2c) the anthraquinone dyes of formulae (IX) and (IX'):

in which formulae (IX) and (IX'):

^• F¾22, R23, R24, R25, R26 and R ₂₇ , which may be identical or different, represent a hydrogen or halogen atom or a group chosen from i) alkyl, ii) hydroxyl, iii) mercapto, iv) alkoxy, v) alkylthio, vi) aryloxy or arylthio which is optionally substituted, preferentially substituted with one or more groups chosen from alkyl and (0) ₂ S(0 , M ⁺ with M ⁺ as defined previously, vii) aryl(alkyl)amino optionally substituted with one or more groups chosen from alkyl and (0) ₂ S(0 ^~ )-, M ⁺ with M ⁺ as defined previously, viii) (di)(alkyl)amino, ix) (di)(hydroxyalkyl)amino, x) (0) ₂ S(0 ^~ )-, M ⁺ with M ⁺ as defined previously;

• Z' represents a hydrogen atom or a group NR ₂₈ 29 with R ₂₈ and R ₂₉ , which may be identical or different, representing a hydrogen atom or a group chosen from i) alkyl, ii) polyhydroxyalkyl such as hydroxyethyl, iii) aryl optionally substituted with one or more groups in particular alkyl such as methyl, n-dodecyl, n-butyl; (0) ₂ S(0 ^~ )-, M ⁺ with M ⁺ as defined previously; R°-C(X)-X'-, R°-X'-C(X)-, R°-X'-C(X)-X"- with R°, X, X' and X" as defined previously, preferentially R° represents an alkyl group, iv) cycloakyl; especially cyclohexyl;

• Z represents a group chosen from hydroxyl and NR' ₂₈ R' ₂₉ with R' ₂₈ and R' ₂₉ , which may be identical or different, representing the same atoms or groups as R ₂₈ and R ₂₉ as defined previously;

it being understood that formulae (IX) and (IX') comprise at least one sulfonate group (0) ₂ S(0 , Q ⁺ .

As examples of dyes of formula (IX), mention may be made of: Acid Blue 25, Acid Blue 43, Acid Blue 62, Acid Blue 78, Acid Blue 129, Acid Blue 138, Acid Blue 140, Acid Blue 251 , Acid Green 25, Acid Green 41 , Acid Violet 42, Acid Violet 43, Mordant Red 3; and as examples of dyes of formula (IX'), mention may be made of Acid Black 48; c2d) the nitro dyes of formulae (X) and (Χ'):

(X) (Χ')

in which formulae (X) and (Χ'):

• R ₃₀ , R ₃₁ and R ₃₂ , which may be identical or different, represent a hydrogen or halogen atom or a group chosen from i) alkyl, ii) alkoxy optionally substituted with one or more hydroxyl groups, iii) alkylthio optionally substituted with one or more hydroxyl groups, iv) hydroxyl, mercapto, v) nitro, nitroso, vi) (poly)haloalkyl, vii) R°-C(X)-X'-, R°-X'-C(X)-, R°-X'-C(X)-X"- with R°, X, X' and X" as defined previously, viii) (0) ₂ S(0 , M ⁺ with M ⁺ as defined previously, ix) (O)CO -, IVT with M ⁺ as defined previously, x) (di)(alkyl)amino, xi) (di)(hydroxyalkyl)amino, xii) heterocycloalkyl such as piperidino, piperazino or morpholino; in particular, R ₃₀ , R31 and R ₃₂ represent a hydrogen atom;

• Rc and R _d , which may be identical or different, represent a hydrogen atom or an alkyl group;

• W is as defined previously; W particularly represents a group -NH-;

• ALK represents a linear or branched divalent C C ₆ alkylene group; in particular, ALK represents a group -CH ₂ -CH ₂ -;

n is 1 or 2;

• p represents an integer between 1 and 5 inclusive;

• q represents an integer between 1 and 4 inclusive;

• u is 0 or 1 ;

• when n is 1 , J represents a nitro or nitroso group; particularly nitro;

• when n is 2, J represents an oxygen or sulfur atom, or a divalent radical -S(0) _m - with m representing an integer 1 or 2; preferentially, J represents a radical -S0 ₂ -; M' is as defined previously for M ⁺ ;

n ^! . _. .f , which may be present or absent, represents a benzo group optionally substituted with one or more groups R ₃₀ as defined previously;

it being understood that formulae (X) and (Χ') comprise at least one sulfonate group (0) ₂ S(0 , Q ⁺ or carboxylate group (0)C(0 , Q ⁺ .

As examples of dyes of formula (X), mention may be made of: Acid Brown 13 and Acid Orange 3; as examples of dyes of formula (Χ'), mention may be made of: Acid Yellow 1 , sodium salt of 2,4-dinitro-1 -naphthol-7-sulfonic acid, 2-piperidino-5- nitrobenzenesulfonic acid, 2-(4'-N,N(2"-hydroxyethyl)amino-2'-nitro)anilineethanesulfon ic acid and 4-p-hydroxyethylamino-3-nitrobenzenesulfonic acid; c2e) the triarylmethane dyes of formula (XI):

in which formula (XI):

^■ R33, R34, R35 and R ₃₆ , which may be identical or different, represent a hydrogen atom or a group chosen from alkyl, optionally substituted aryl and optionally substituted arylalkyl; particularly an alkyl group and benzyl optionally substituted with a group (0) _m S(0 ^~ )-, M ⁺ with M ⁺ and m as defined previously;

^■ R ₃₇ , R ₃₈ , R ₃₉ , R ₄₀ , R41 , R ₄₂ , R43 and R ₄₄ , which may be identical or different, represent a hydrogen atom or a group chosen from: i) alkyl; ii) alkoxy, alkylthio; iii) (di)(alkyl)amino; iv) hydroxyl, mercapto; v) nitro, nitroso; vii) R°-C(X)-X'-, R°- X'-C(X)-, R°-X'-C(X)-X"- with R° representing a hydrogen atom or an alkyl or aryl group; X, X' and X", which may be identical or different, representing an an oxygen or sulfur atom or NR with R representing a hydrogen atom or an alkyl group; viii) (0) ₂ S(0 , M ⁺ with M ⁺ representing a hydrogen atom or a cationic counterion; ix) (O)CO -, IVT with M ⁺ as defined previously;

■ or alternatively two contiguous groups R ₄₁ with R ₄₂ or R ₄₂ with R ₄₃ or R ₄₃ with R ₄₄ together form a fused benzo group: Γ; with Γ optionally substituted with one or more groups chosen from i) nitro; ii) nitroso; iii) (0) ₂ S(0 , M ⁺ ; iv) hydroxyl; v) mercapto; vi) (di)(alkyl)amino; vii) R°-C(X)-X'-; viii) R°-X'-C(X)- and ix) R°-X'-C(X)- X"-; with M ⁺ , R°, X, X' and X" as defined previously;

particularly, R ₃₇ to R ₄₀ represent a hydrogen atom, and R ₄₁ to R ₄₄ , which may be identical or different, represent a hydroxyl group or (0) ₂ S(0 ^~ )-, M ⁺ ; and when R ₄₃ with R ₄₄ together form a benzo group, it is preferentially substituted with a group (0) ₂ S(0 ;

it being understood that at least one of the rings G, H, I or Γ comprises at least one sulfonate (0) ₂ S(0 , M ⁺ or carboxylate (0)C(0 , M ⁺ group.

As examples of dyes of formula (XI), mention may be made of: Acid Blue 1 ; Acid Blue 3; Acid Blue 7, Acid Blue 9; Acid Violet 49 and Acid Green 50; c2f) the xanthene-based dyes of formula (XII):

in which formula (XII):

^■ R ₄₅ , 46, R47 and R ₄₈ , which may be identical or different, represent a hydrogen or halogen atom;

^■ R49, R50, R51 and R ₅₂ , which may be identical or different, represent a hydrogen or halogen atom or a group chosen from i) alkyl; ii) alkoxy, alkylthio; iii) hydroxyl, mercapto; iv) nitro, nitroso; v) (0) ₂ S(0 , M ⁺ with M ⁺ representing a hydrogen atom or a cationic counterion; vi) (O)CO -, IVT with M ⁺ as defined previously;

particularly R ₅₃ , R ₅₄ , R ₅₅ and R ₄₈ represent a hydrogen or halogen atom;

^■ G represents an oxygen or sulfur atom or a group NR _e with R _e as defined previously; particularly, G represents an oxygen atom;

^■ L represents an alkoxide O ^" , M ⁺ ; a thioalkoxide S ^" , M ⁺ or a group NR _f , with R, representing a hydrogen atom or an alkyl group and M ⁺ as defined previously; M ⁺ is particularly Na ⁺ or K ⁺ ;

^■ L' represents an oxygen or sulfur atom or an ammonium group: N ⁺ R _f R _g , with R _f and R _g , which may be identical or different, representing a hydrogen atom, an alkyl group or an optionally substituted aryl; L' represents particularly an oxygen atom or a phenylamino group optionally substituted with one or more alkyl or (0) _m S(0 , M ⁺ groups with m and M ⁺ as defined previously;

^■ Q and Q', which may be identical or different, represent an oxygen or sulfur atom; particularly Q and Q' represent an oxygen atom;

^■ M ⁺ is as defined previously;

it being understood that formula (XII) comprises at least one sulfonate group (0) ₂ S(0 ^~ )-, Q ⁺ or carboxylate group (O)C(O )-, Q ⁺ with Q ⁺ as defined previously.

As examples of dyes of formula (XII), mention may be made of the ammonium salts derived from: Acid Yellow 73; Acid Red 51 ; Acid Red 87; Acid Red 92; Acid Red 95 and Acid Violet 9;

c2g) synthetic indigoid dyes, especially of formula (XIII):

in which formula (XIII):

^■ R53, R54, R55, R56, R57, R58, R59 and R ₆₀ , which may be identical or different, represent a hydrogen atom or a group chosen from: i) alkyl; ii) alkoxy, alkylthio; iii) hydroxyl, mercapto; iv) nitro, nitroso; v) R°-C(X)-X'-, R°-X'-C(X)-, R°-X'-C(X)- X"- with R° representing a hydrogen atom or an alkyl or aryl group; X, X' and X", which may be identical or different, representing an an oxygen or sulfur atom or NR with R representing a hydrogen atom or an alkyl group; vi) (0) ₂ S(0 , M ⁺ with M ⁺ as defined previously; vii) (O)CO -, IVT with M ⁺ as defined previously;

^■ G represents an oxygen or sulfur atom or a group NR _e with R _e as defined previously; particularly, G represents an oxygen atom;

^■ Ri and R _h , which may be identical or different, represent a hydrogen atom or an alkyl group;

it being understood that at least one of the groups R ₅₃ , R ₅₄ , R ₅₅ , R ₅₆ , R ₅₇ , R ₅₈ , R59 or R ₆₀ , represents a sulfonate group (0) ₂ S(0 , M ⁺ or carboxylate group (0)C(0 , M ⁺

As examples of dyes of formula (XIII), mention may be made of Acid Blue 74 and indigo carmine (or indigotine I, blue CI No. 1 ) or blue dye (number E132).

According to a preferred embodiment, the anionic direct dye is chosen from the anionic dyes of formula (XIII).

Preferably, the anionic dye is chosen from indigoids such as carmine indigo. c2h) The quinoline-based d

R ₆ i represents a hydrogen or halogen atom or an alkyl group;

R ₆₂ , Re3 and R ₆ 4, which may be identical or different, represent a hydrogen atom or a group (0) ₂ S(0 , M ⁺ with M ⁺ as defined previously;

or alternatively R ₆ i with R ₆₂ , or R ₆₁ with R ₆₄ , together form a benzo group optionally substituted with one or more groups (0) ₂ S(0 , M ⁺ with M ⁺ representing a hydrogen atom or a cationic counterion; it being understood that formula (XIV) comprises at least one sulfonate group (0) ₂ S(0 , Q ⁺ with Q ⁺ as defined previously.

As examples of dyes of formula (XIV), mention may be made of the ammonium salts derived from: Acid Yellow 2, Acid Yellow 3 and Acid Yellow 5.

More particularly, the dyes of formulae (VII) to (XIV) that are useful in the invention

Most of these dyes are described in particular in the Colour Index published by The Society of Dyers and Colourists, P.O. Box 244, Perkin House, 82 Grattan Road, Bradford, Yorkshire, BD1 2JBN England. The anionic dyes that are more particularly preferred are the dyes designated in the Colour Index under the code C.I. 58005 (monosodium salt of 1 ,2-dihydroxy-9,10-anthraquinone-3-sulfonic acid), C.I. 60730 (monosodium salt of 2- [(9,10-dihydro-4-hydroxy-9,10-dioxo-1 -anthracenyl)amino]-5-methylbenzenesulfonic acid), C.I. 15510 (monosodium salt of 4-[(2-hydroxy-1 -naphthalenyl)azo]benzenesulfonic acid), C.I. 15985 (disodium salt of 6-hydroxy-5-[(4-sulfophenyl)azo]-2- naphthalenesulfonic acid), C.I. 17200 (disodium salt of 5-amino-4-hydroxy-3-(phenylazo)- 2,7-naphthalenedisulfonic acid), C.I. 20470 (disodium salt of 1 -amino-2-(4'- nitrophenylazo)-7-phenylazo-8-hydroxy-3,6-naphthalenedisulfo nic acid), C.I. 42090 (disodium salt of N-ethyl-N-[4-[[4-[ethyl(3-sulfophenyl)methyl]amino]phenyl](2 - sulfophenyl)methylene]-2,5-cyclohexadien-1 -ylidene]-3-sulfobenzenemethanamini hydroxide, inner salt), C.I. 61570 (disodium salt of 2,2'-[(9,10-dihydro-9,10-dioxo-1 ,4- anthracenediyl)diimino]bis[5-methyl]benzenesulfonic acid).

The composition used according to the invention may of course comprise a mixture of dyes of formulae (VII), (VII'), (VIII), (VIII'), (IX), (ΙΧ'), (X), (Χ'), (XI), (XII), (XIII) and (XIV).

It is also possible to use compounds corresponding to the mesomeric or tautomeric forms of structures (VII) to (XIV).

In particular, the dye(s) c) according to the invention are chosen from those of formulae (VII'), (VIII), (VIII'), (IX), (ΙΧ'), (X), (Χ'), (XI), (XII), (XIII) and (XIV), and mixtures thereof, more particularly (VIII), (VIII'), (IX), (ΙΧ'), (X), (Χ'), (XI), (XII), (XIII) and (XIV) and mixtures thereof, such as (IX), (ΙΧ'), (X), (Χ'), (XI), (XII), (XIII) and (XIV).

More particularly, the dye(s) c) of the invention are not azo anionic dyes.

Preferentially, the synthetic direct dye(s) of the invention are chosen from acidic nitro dyes, acidic azine dyes, acidic triarylmethane dyes, acidic indoamine dyes, acidic anthraquinone dyes, and indigoids.

Preferably, the anionic direct dye(s) are chosen from the dyes of formulae (VII), (IX) and (XIII), in particular chosen from Acid Black 1 , Acid Blue 62, Acid Red 18 and carmine indigo; and more preferentially (XIII), in particular carmine indigo. In this embodiment, the total content of anionic synthetic direct dyes c) in the dye composition comprising them is preferably between 0.001 % and 20% by weight, preferably between 0.001 % and 10% by weight, preferably between 0.001 % and 5% by weight, relative to the weight of composition comprising them. c3) According to another particular embodiment of the invention, the dye(s) are chosen from the cationic synthetic direct dyes or dyes commonly referred to as "basic" direct dyes or "basic dyes" on account of their affinity for acidic substances. The cationic dyes are preferentially chosen from hydrazono dyes, (poly)azo dyes, polymethine dyes such as styryl dyes and (poly)arylmethane dyes. More preferentially, the cationic dye(s) of the invention are chosen from the hydrazono dyes of formulae (XVIIIa) and (XVIII'a), the azo dyes (XlXa) and (XlX'a) and the diazo dyes (XXa) below:

(XVIIIa) (XVIII'a) (XlXa)

Ar+-N=N-Ar", Q_ _and Het ⁺ -N=N-Ar'-N=N-Ar, Q ^"

(XlX'a) (XXa) formulae (XVIIIa), (XVIII'a), (XlXa), (XlX'a) and (XXa) with: > Het ⁺ representing a cationic heteroaryl radical, preferentially bearing an endocyclic cationic charge, such as imidazolium, indolium or pyridinium, optionally substituted preferentially with one or more (CrC ₈ ) alkyl groups such as methyl;

> Ar ⁺ representing an aryl radical, such as phenyl or naphthyl, bearing an exocyclic cationic charge, preferentially ammonium, particularly tri(Ci-C ₈ )alkylammonium such as trimethylammonium;

> Ar representing an aryl group, especially phenyl, which is optionally substituted, preferentially with one or more electron-donating groups such as i) optionally substituted (CrC ₈ )alkyl, ii) optionally substituted (CrC ₈ )alkoxy, iii) (di)(C C ₈ )(alkyl)amino optionally substituted on the alkyl group(s) with a hydroxyl group, iv) aryl(Ci-C ₈ )alkylamino, v) optionally substituted A/-(Ci-C ₈ )alkyl-/V-aryl(Ci- C ₈ )alkylamino or alternatively Ar representing a julolidine group;

> Ar' being an optionally substituted divalent (hetero)arylene group such as phenylene, particularly para-phenylene, or naphthalene, optionally substituted, preferentially with one or more (CrC ₈ )alkyl, hydroxyl or (d-C ₈ )alkoxy groups;

> Ar" an optionally substituted (hetero)aryl group such as phenyl or pyrazolyl, optionally substituted, preferentially with one or more (CrC ₈ )alkyl, hydroxyl, (di)(Ci-C ₈ )(alkyl)amino, (Ci-C ₈ )alkoxy or phenyl groups;

> R ^a and R ^b , which may be identical or different, representing a hydrogen atom or a (CrC ₈ )alkyl group, which is optionally substituted, preferentially with a hydroxyl group;

or alternatively the substituent R ^a with a substituent of Hef and/or R ^b with a substituent of Ar and/or R ^a with R ^b forming, together with the atoms that bear them, a (hetero)cycloalkyl;

particularly, R ^a and R ^b representing a hydrogen atom or a (CrC ₄ )alkyl group, which is optionally substituted with a hydroxyl group;

> Q ^" representing an anionic counterion, and preferably represents a halide or a mesylate.

According to a preferred variant of the invention, the dye(s) c) are cationic and are chosen from the polymethine dyes of formulae (XXIa) and (XXI'a) below:

W ⁺ -[C(R ^c )=C(R ^d )] _m -Ar', Q Ar-[C(R ^d )=C(R ^c )] _m -W' ⁺ , Q

(XXIa) (XXI'a)

formulae (XXIa) or (XXI'a) with:

• W ⁺ representing a cationic heterocyclic or heteroaryl group, particularly comprising a quaternary ammonium optionally substituted with one or more (CrC ₈ )alkyl groups optionally substituted especially with one or more hydroxyl groups;

• W' ⁺ representing a heterocyclic or heteroaryl radical as defined for W ⁺ ; • Ar representing a (hetero)aryl group such as phenyl or naphthyl, optionally substituted preferentially with i) one or more halogen atoms such as chlorine or fluorine; ii) one or more (CrC ₈ )alkyl groups, preferably CrC ₄ such as methyl; iii) one or more hydroxyl groups; iv) one or more (d-C ₈ )alkoxy groups such as methoxy; v) one or more hydroxy(CrC ₈ )alkyl groups such as hydroxyethyl, vi) one or more amino or (di)(Ci- C ₈ )alkylamino groups, preferably with the Ci-C ₄ alkyl part optionally substituted with one or more hydroxyl groups, such as (di)hydroxyethylamino, vii) with one or more acylamino groups; viii) one or more heterocycloalkyl groups such as piperazinyl, piperidyl or 5- or 6-membered heteroaryl such as pyrrolidinyl, pyridyl and imidazolinyl; · Ar' being a (hetero)aryl radical as defined for Ar;

• m' representing an integer between 1 and 4 inclusive, and in particular m has the value 1 or 2; more preferentially 1 ;

• R°,R ^d , which may be identical or different, representing a hydrogen atom or an optionally substituted (CrC ₈ )alkyl group, preferentially CrC ₄ , or alternatively R ^c contiguous with W ⁺ or W' ⁺ and/or R ^d contiguous with Ar or Ar' and/or contiguous R ^c and R ^d forming, with the atoms that bear them, a (hetero)cycloalkyl, particularly R ^c is contiguous with W ⁺ or W' ⁺ and forms a (hetero)cycloalkyl such as cyclohexyl;

• Q ^" as defined previously, preferably representing a halide or a mesylate.

Mention may be made more particularly of the azo and hydrazono dyes bearing endocyclic cationic charges of formulae (XlXa), (XlX'a), (XXIa) and (XXI'a) as defined previously, more particularly those of formulae (XlXa), (XlX'a) and (XXIa) described in patent applications WO 95/15144, WO 95/01772 and EP-714954. Preferentially, the dye(s) c) are cationic and comprise an endocyclic cationic charge and in particular have the following formulae:

(XVIIIa-1) (XIXa-1)

formulae (XVIIIa-1) and (XIXa-1) with:

- R ¹ representing a (CrC ₄ )alkyl group such as methyl;

- R ² and R ³ , which may be identical or different, representing a hydrogen atom or a (C

C ₄ )alkyl group, such as methyl; and

- R ⁴ representing a hydrogen atom or an electron-donating group such as optionally substituted (CrC ₈ )alkyl, optionally substituted (CrC ₈ )alkoxy, or (di)(CrC ₈ )(alkyl)amino optionally substituted on the alkyl group(s) with a hydroxyl group; particularly, R ⁴ is a hydrogen atom, - Z representing a group CH or a nitrogen atom, preferentially CH,

- Q ^" as defined previously, preferably representing a halide or a mesylate.

In particular, the dyes of the invention are chosen from those of formula (XXVIa-1 ) and (XXVa-1 ) is chosen from Basic Red 51 , Basic Yellow 87 and Basic Orange 31 or derivatives thereof:

Basic Red 51 Basic Orange 31 Basic Yellow 87 with Q ^" as defined previously, preferably representing a halide or a mesylate. c4) According to another embodiment of the invention, the dye(s) are chosen from natural or synthetic self-oxidizing dyes, preferably chosen from indole and indoline compounds. The term "self-oxidizing" dyes means dyes which are uncoloured and which become coloured with atmospheric oxygen. c4a) According to a particular embodiment, compound(s) c) are chosen from the synthetic indole compounds especially of formula (XVa) below:

in which formula (XVa):

- R _! and R ₃ , which may be identical or different, represent a hydrogen atom or a CrC ₄ alkyl radical, preferably hydrogen;

- R ₂ represents a hydrogen atom, a Ci-C ₄ alkyl radical, a hydroxyl or amino group, or - C(0)-OH, preferably hydrogen;

- X denotes a hydrogen atom, -OH, a Ci-C ₄ alkyl radical, a Ci-C ₄ alkoxy radical or a radical -0-C(0)-R with R representing H or a CrC ₄ alkyl such as methyl; - Y denotes -OH, or a radical -0-C(0)R with R as defined previously; preferably, Y is in position 5 and X is in position 6; and also the organic or mineral acid or base salts thereof.

As indole compounds of formula (XVa) according to the invention, mention may be made of 5,6-dihydroxyindole, 2-methyl-5,6-dihydroxyindole, 3-methyl-5,6-dihydroxyindole, 4- hydroxyindole, 2,3-dimethyl-5,6-dihydroxyindole, 6-hydroxy 5-methoxyindole, 6- hydroxyindole, 5-hydroxyindole, 7-hydroxyindole, 7-aminoindole, 5-aminoindole, 5,6- dihydroxyindole-2-carboxylic acid, 5-aminoindole, 1-methyl-5,6-dihydroxyindole, 5- acetyloxy-6-hydroxyindole, 6-acetyl-5-hydroxyindole and 5,6-diacetyloxyindole, and the organic or mineral acid or base salts thereof. c4b) According to another embodiment, the compound(s) c) of the invention are synthetic indoline compounds and in particular of formula (XVb) below:

in which formula (XVb) R _{1 ;} R ₂ , R ₃ , X and Y have the same meanings as those indicated above for the compounds of formula (XVa), and also the enantiomers and diastereoisomers, and the organic or mineral acid or base salts thereof.

Among the preferential indoline compounds of formula (XVb), mention may be made of

5.6- dihydroxyindoline, A/-methyl-5,6-dihydroxyindoline, A/-ethyl-5,6-dihydroxyindoline, N- butyl-5,6-dihydroxyindoline, 4-hydroxy-5-methoxyindoline, 6-hydroxy-7-methoxyindoline,

6.7- dihydroxyindoline, 4,5-dihydroxyindoline and 5-methoxy-6-hydroxyindoline, and the organic or mineral acid or base salts thereof.

Even more preferentially, the compound(s) c) are chosen from 5,6-dihydroxyindole and 5,6-dihydroxyindoline, and also the organic or mineral acid or base salts thereof. c4c) According to another particular embodiment of the invention, the dye(s) c) are chosen from natural indole or indoline compounds. The invention may then be performed using one or more natural extracts of animals, bacteria, fungi, algae or plants comprising one or more indole or indoline compounds.

According to a particular embodiment, the dye(s) c) are derived from an extract of beetroot, especially red beetroot. The extract of red beetroot or Beta vulgaris is preferentially an extract obtained from red beetroot, especially from the periphery or outer part of beetroot, more particularly from red beetroot skin or peel (Eur. Food. Res. Technol., Tytti S. Kujala et al., 214, 505-510 (2002).

The term "red beetroot skin" more particularly denotes the peripheral part of the tuber situated between the epidermis and the pericarp (cf. Hermann et al., Journal of Experimental Botany, Vol. 58, No. 11 , pp. 3047-3060, 2007).

The extracts are obtained by extracting the various plant parts, for instance the root, the leaves or the peel. Preferentially, the extract is obtained from extraction of red beetroot peel.

The extraction is performed via standard methods known to those skilled in the art. Mention may be made, for example, of the method described in Eur. Food. Res. Technol., Tytti S. Kujala et al., 214, 505-510 (2002)).

The natural red beetroot extracts according to the invention may be in the form of powders or liquids. Preferentially, the extracts of the invention are in the form of powders, such as red beetroot peel extract powders.

According to the invention, the red beetroot extract(s) used as ingredient c) in one or more composition(s) that are useful in the process according to the invention preferably represent from 0.001% to 20% by weight relative to the total weight of the composition(s) containing said extract(s). In the context of the present invention, the dye(s) c) are preferably present in a total amount ranging from 0.001% to 80% by weight relative to the total weight of the dye composition, in particular ranging from 0.005% to 20% by weight relative to the total weight of the dye composition, preferentially from 0.01% to 10% by weight and better still from 0.01% to 5% by weight relative to the total weight of the composition containing them.

As regards the pure natural dyes, especially the pure ODPs, the content in the composition containing them is preferably between 0.001% and 5% by weight of each of the composition containing them.

As regards the extracts, the content in the composition(s) containing the extract(s) per se is preferably between 0.1% and 20% by weight of the composition containing them.

In the context of the present invention, the self-oxidizing dye(s) are generally present in a total amount ranging from 0.001% to 10% by weight approximately relative to the total weight of the dye composition comprising them, preferably ranging from 0.005% to 5% by weight relative to the total weight of the composition containing them. d) basifying agent(s) According to a particular embodiment of the invention, the dyeing process uses one or more basifying agents d). Preferably, the basifying agent(s) d) are in the dye composition with the dye(s) as defined previously.

These basifying agents are bases that can increase the pH of the composition(s) in which they are present. The basifying agent is a Bronsted, Lowry or Lewis base. It may be mineral or organic.

Particularly, said agent is chosen from i) (bi)carbonates, ii) aqueous ammonia, iii) alkanolamines such as monoethanolamine, diethanolamine, triethanolamine and derivatives thereof, iv) oxyethylenated and/or oxypropylenated ethylenediamines, v) mineral or organic hydroxides, vi) alkali metal silicates such as sodium metasilicate, vii) amino acids, preferably basic amino acids such as arginine, lysine, ornithine, citrulline and histidine, and viii) the compounds of formula (XVII) below:

N - W- N

R R

d (XVII)

in which formula (XVII) W is a divalent (d-C ₈ )alkylene radical optionally substituted with at least one hydroxyl group or at least one (CrC ₄ )alkyl radical and/or optionally interrupted with at least one heteroatom, such as oxygen or sulfur, or with an -N(R _e )- group; R _a , Rb, R _c , Rd and R _e , which may be identical or different, represent a hydrogen atom or a (CrC ₄ )alkyl or hydroxy^ -C ₄ )alkyl radical; preferably, W represents a propylene radical. The mineral or organic hydroxides are preferably chosen from a) hydroxides of an alkali metal, b) hydroxides of an alkaline-earth metal, for instance sodium hydroxide or potassium hydroxide, c) hydroxides of a transition metal, such as hydroxides of metals from groups III, IV, V and VI, d) hydroxides of lanthanides or actinides, quaternary ammonium hydroxides and guanidinium hydroxide.

The hydroxide may be formed in situ, for instance guanidine hydroxide, formed by reacting calcium hydroxide with guanidine carbonate.

The term "(bi)carbonates" i) is understood to mean:

a) carbonates of alkali metals (Met ₂ ⁺ , C0 ₃ ^2~ ), of alkaline-earth metals (Met' ²⁺ , C0 ₃ ^2~ ), of ammonium ((R" ₄ N ⁺ ) ₂ ,C0 ₃ ^2~ ) or of phosphonium ((R" ₄ P ⁺ ) ₂ ,C0 ₃ ^2" with Met' representing an alkaline-earth metal and Met representing an alkali metal, and R", which may be identical or different, representing a hydrogen atom or an optionally substituted (CrC ₆ )alkyl group such as hydroxyethyl), and

b) bicarbonates, also known as hydrogen carbonates, of the following formulae:

> R' ⁺ , HC0 ₃ ^" , with R' representing a hydrogen atom, an alkali metal, an ammonium group R" ₄ N ⁺ - or a phosphonium group R" ₄ P ⁺ -, where R", which may be identical or different, represent a hydrogen atom or an optionally substituted (CrC ₆ )alkyl group, such as hydroxyethyl, and, when R' represents a hydrogen atom, the hydrogen carbonate is then known as dihydrogen carbonate (C0 ₂ , H ₂ 0); and > Met' ²⁺ (HC0 ₃ ^~ ) ₂ with Met' representing an alkaline-earth metal.

More particularly, the basifying agent is chosen from alkali metal or alkaline-earth metal (bi)carbonates and amino acids such as arginine; preferentially alkali metal (bi)carbonates and amino acids.

Mention may be made of Na, K, Mg and Ca carbonates or hydrogen carbonates and mixtures thereof, and in particular sodium hydrogen carbonate. These hydrogen carbonates may originate from a natural water, for example spring water from the Vichy basin or from La-Roche Posay or Badoit water (cf. for example, patent document FR 2 814 943). Mention may in particular be made of sodium carbonate [497-19-8] = Na ₂ C0 ₃ , sodium hydrogen carbonate or sodium bicarbonate [144-55-8] = NaHC0 ₃ , and sodium dihydrogen carbonate = Na(HC0 ₃ ) ₂ .

According to a particularly advantageous embodiment, the basifying agent(s) d) are chosen from aqueous ammonia, carbonates and hydrogen carbonates.

When they are present, the basifying agent(s) d) as defined previously preferably represent from 0.001% to 10% by weight relative to the weight of the composition(s) containing them, and more particularly from 0.005% to 8% by weight of the composition. The compositions:

The compositions according to the invention generally comprise water or a mixture of water and of one or more organic solvents or a mixture of organic solvents.

The term "organic solvent" means an organic substance that is capable of dissolving or dispersing another substance without chemically modifying it.

The organic solvents:

Examples of additional organic solvents that may be mentioned include Ci-C ₄ lower alkanols, such as ethanol and isopropanol; polyols and polyol ethers such as 2- butoxyethanol, propylene glycol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, hexylene glycol, and also aromatic alcohols, such as benzyl alcohol or phenoxyethanol.

The organic solvents are present in proportions preferably of between 1% and 40% by weight approximately and more preferably still between 5% and 30% by weight approximately, relative to the total weight of the dye composition. The adjuvants:

The compositions of the dyeing process in accordance with the invention may also contain various adjuvants conventionally used in hair dye compositions, such as anionic, cationic, nonionic, amphoteric or zwitterionic surfactants or mixtures thereof, anionic, cationic, nonionic, amphoteric or zwitterionic polymers or mixtures thereof, mineral or organic thickeners, and in particular anionic, cationic, nonionic and amphoteric polymeric associative thickeners, antioxidants, penetrants, sequestrants, fragrances, buffers, dispersants, conditioning agents, for instance volatile or non-volatile modified or unmodified silicones, film-forming agents, ceramides, preserving agents and opacifiers.

Said adjuvants are preferably chosen from surfactants such as anionic or nonionic surfactants or mixtures thereof and mineral or organic thickeners.

The above adjuvants are generally present in an amount for each of them of between 0.01% and 40% by weight relative to the weight of the composition, and preferably between 0.1% and 20% by weight relative to the weight of the composition.

Needless to say, a person skilled in the art will take care to select this or these optional additional compounds such that the advantageous properties intrinsically associated with the composition(s) that are useful in the dyeing process in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition(s).

The cosmetic composition(s) of the invention may be in various galenical forms, such as a powder, a lotion, a mousse, a cream or a gel, or in any other form that is suitable for dyeing keratin fibres. They may also be packaged in a propellant-free pump-action bottle or under pressure in an aerosol container in the presence of a propellant and form a mousse. e) pH of the composition(s):

Preferably, the pH of at least one of the cosmetic compositions comprising at least one of the ingredients a) to d) is acidic, i.e. it has a pH of less than 7.0, preferably less than 5.0, in particular is at a pH of between 0 and 4 inclusive, more particularly between 0.5 and 3.5, preferably between 1 and 3. Preferably, the composition comprising a) is acidic, preferably has a pH of less than 5.0, and is particularly at a pH of between 0 and 4, more particularly between 0.5 and 3.5 and preferably between 1 and 3.

According to one embodiment, the pH of the cosmetic composition(s) containing one or more alkaline agents d) is alkaline, i.e. greater than 7, preferably between 8 and 12 and more particularly between 8 and 11 inclusive.

Preferably, the composition containing the alkaline agent(s) is the dye composition as defined previously.

According to a particular embodiment of the invention, the composition containing the titanium salt(s) a) and not containing any basifying agent d) has a pH of less than 7 and preferably of less than 5, in particular is at a pH between 0 and 4.

The pH of these compositions may be adjusted to the desired value by means of basifying agents d) as defined previously or by using acidifying agents usually used in the dyeing of keratin fibres, or alternatively by means of standard buffer systems. Among the acidifying agents for the compositions used in the invention, examples that may be mentioned include mineral or organic acids, for instance hydrochloric acid, orthophosphoric acid, sulfuric acid, carboxylic acids as defined previously, for instance acetic acid, tartaric acid, citric acid or lactic acid, or sulfonic acids.

Dyeing process in one or more steps According to a first particular embodiment of the invention, the dyeing process involves the simultaneous application of ingredients a), b) and c) as defined previously, i.e. the dyeing process of the invention comprises at least one step of applying to keratin fibres, in particular human keratin fibres such as the hair, a cosmetic composition Ci) comprising:

a) at least one titanium salt as defined previously;

b) optionally one or more carboxylic acids of formula (I) as defined previously; and c) at least one dye chosen from cationic, anionic or neutral natural dyes or synthetic direct dyes and self-oxidizing dyes; in particular chosen from natural dyes that are more particularly neutral, preferably chosen from ODPs;

it being understood that:

- the process does not use any chemical oxidizing agent; and

- c) is other than anionic direct dye comprising a 1 ,8-dihydroxynaphthalene-3,5- disulfonate group,

preparation Ci) being able to be prepared by extemporaneous mixing of ingredients a), b) and c).

According to a preferred embodiment of the invention, the dyeing process involves the simultaneous application of ingredients a), b) and c) as defined previously, i.e. the dyeing process of the invention comprises at least one step of applying to keratin fibres, in particular human keratin fibres such as the hair, a cosmetic composition Ci) comprising:

a) at least one titanium salt as defined previously;

b) optionally one or more carboxylic acids of formula (I) as defined previously; and c) at least one dye chosen from cationic, anionic or neutral natural dyes or synthetic direct dyes and self-oxidizing dyes, preferably chosen from ODPs;

it being understood that the process does not use any chemical oxidizing agent.

According to another particular embodiment of the invention, the dyeing process sequentially uses ingredients a), b) and c) as defined previously.

In one variant of this sequential embodiment, the process for dyeing keratin fibres of the invention comprises several steps:

i) applying at least one "pretreatment" cosmetic composition Cii) containing:

a) at least one titanium salt as defined previously; and optionally

b) at least one carboxylic acid of formula (I) as defined previously, preferably b) is present in the pretreatment composition;

and subsequently:

ii) applying at least one cosmetic "dye" composition Ciii) containing:

c) at least one dye chosen from cationic, anionic or neutral natural dyes or synthetic direct dyes and self-oxidizing dyes; in particular chosen from natural dyes that are more particularly neutral, preferably chosen from ODPs;

it being understood that the process does not use any chemical oxidizing agent. According to a particular embodiment, intermediate rinsing is performed between the steps of applying compositions Cii) and Ciii).

In another particular variant of the invention, the process for dyeing keratin fibres comprises:

i) the application of at least one "dyeing" cosmetic composition Ciii) containing:

c) at least one dye chosen from cationic, anionic or neutral natural dyes or synthetic direct dyes and self-oxidizing dyes; in particular chosen from natural dyes that are more particularly neutral, preferably chosen from ODPs;

and subsequently:

ii) the application of at least one "post-treatment" cosmetic composition Cii) containing: a) at least one titanium salt as defined previously; and optionally

b) at least one carboxylic acid of formula (I) as defined previously, preferably b) is present in the post-treatment composition;

it being understood that the process does not use any chemical oxidizing agent. Intermediate rinsing may optionally be performed between steps of applying compositions Ciii) and Cii).

Preferentially, an intermediate rinsing step is included between the application of compositions Cii) and then Ciii). In the sequential embodiment, the preferred embodiment is the process for dyeing keratin fibres of the invention, which comprises several steps:

i) the application of at least one "pretreatment" cosmetic composition Cii) containing: a) at least one titanium salt as defined previously; and optionally

b) at least one carboxylic acid of formula (I) as defined previously, preferably b) is present in the pretreatment composition;

and subsequently:

ii) the application of at least one cosmetic "dye" composition Ciii) containing:

c) at least one dye chosen from cationic, anionic or neutral natural dyes or synthetic direct dyes and self-oxidizing dyes; in particular chosen from natural dyes that are more particularly neutral, preferably chosen from ODPs;

it being understood that the process does not use any chemical oxidizing agent, intermediate rinsing being performed between the steps of applying compositions Cii) and Ciii).

According to a particular embodiment of the invention, composition Ci) is at acidic pH, i.e. less than 7, preferably less than 5, in particular at a pH of between 0 and 4 inclusive, more particularly between 0.5 and 3.5 and more preferentially between 1 and 3.

According to a particular embodiment of the invention, composition Cii) is at acidic pH, i.e. less than 7, preferably less than 5, in particular at a pH of between 0 and 4 inclusive, more particularly between 0.5 and 3.5 and more preferentially between 1 and 3.

According to a particular embodiment of the invention, composition Ciii) is at acidic pH, i.e. less than 7, preferably less than 6, in particular at a pH of between 1 and 5 inclusive, more particularly between 2 and 4.

Preferentially, compositions Ci), Cii) and Ciii) are aqueous.

According to a particular embodiment, the process for dyeing keratin fibres of the invention involves:

> either the application to said fibres of composition Cii) as defined previously, followed by at least one rinsing of said fibres preferably with water, in particular with tap water, and then the application to said fibres of composition Ciii);

> or the application to said fibres of composition Ciii) as defined previously, followed by at least one rinsing of said fibres preferably with water, in particular with tap water, and then the application to said fibres of composition Cii) as defined previously;

> it being understood that the process does not use any chemical oxidizing agent. Preferentially, the organic titanium salt(s) of composition Ci) as defined previously, or Cii) as defined previously, of the process of the invention are chosen from those of formulae (l-A) or (l-B) or the salts of dihydroxybis(lactato)titaniumlV as defined previously.

According to a preferred embodiment of the invention, the dyeing process involves the application to said fibres of composition Cii) as defined previously, optionally followed by rinsing said fibres, preferably with water, followed by the application to said fibres of composition Ciii) as defined previously.

In particular, in the dyeing process of the invention, the leave-on time of composition Ci), Cii) or Ciii) as defined previously on the keratin fibres is between 5 minutes and 2 hours, more particularly between 15 minutes and 1 hour, preferably between 30 and 45 minutes. Preferentially, the leave-on time of composition Ci), Cii) or Ciii) as defined previously on the keratin fibres is maintained at a temperature of between 20°C and 50°C, more preferentially between room temperature (25°C) and 40°C.

According to a particular embodiment of the invention, between the application of compositions Cii) and Ciii) or Ciii) and Cii) as defined previously, at least one rinse is performed in the process of the invention. Preferably, rinsing is performed with tap water, preferably until the residual rinsing water of the keratin fibres is visually clear and transparent, identical to the water before treatment of the keratin fibres.

This dye composition is preferably prepared a few minutes before application, in particular between 1 minute and 1 hour, more particularly between 5 minutes and 30 minutes, before application.

According to a particular embodiment of the invention, the dye composition Ci) or Ciii) also comprises one or more basifying agents d) as defined previously, in particular aqueous ammonia, or monoethanolamine or carbonates or hydrogen carbonates; preferably aqueous ammonia or monoethanolamine.

After applying compositions Ci), Cii) and/or Ciii) as defined previously, the dyeing process of the invention may involve one or more shampoo washes, followed by one or more rinses with water of the keratin fibres, optionally followed by drying via a heat treatment by heating to a temperature of between 30 and 60°C.

Use may also be made, as a means for both heating and for straightening the head of hair, of a heating iron at a temperature of between 60 and 220°C and preferably between 120 and 200°C.

The term "drying" means the action of evaporating the organic solvents and/or water present in one or more compositions used in the process of the invention. The drying may be performed with a source of heat (convection, conduction or radiation) by sending, for example, a stream of hot gas such as air necessary to evaporate the solvent(s). Sources of heat that may be mentioned include a hairdryer, a hairstyling hood, a hair-straightening iron, an infrared ray dispenser and other standard heating appliances.

One particular mode of the invention relates to a dyeing process that is performed at room temperature (20°C).

In all the particular forms and variants of the processes previously described, the compositions mentioned are ready-to-use compositions that may result from the extemporaneous mixing of two or more compositions and in particular of compositions present in dyeing kits.

The examples that follow serve to illustrate the invention without, however, being limiting in nature.

EXAMPLES OF DYEING

Example 1 : The following compositions are prepared from the following ingredients in the following proportions, indicated in grams:

^■ Pretreatment composition Cii):

The pretreatment composition Cii) is applied onto locks of natural Caucasian hair containing 90% white hairs (NW) and left to stand on the locks for 45 minutes at 40°C and then rinsed out.

The dye composition Ciii) is then applied and left to stand on the locks for 45 minutes at 40°C comparatively with certain locks that have not undergone the pretreatment with composition Cii).

After these leave-on times, the locks are washed with Elvive multivitamin shampoo, rinsed and then dried under a hood.

Dyeing results The colourings obtained with the dyeing process according to the invention, i.e. which uses titanium salt, are intense and of varied colours, even in the absence of oxidizing agent. In addition, it is seen that the colouring is visually more homogeneous with the process of the invention than when the dyeing process does not involve pretreatment with the titanium salt.

These results are corroborated by the colorimetric measurements below.

The colour of the locks was evaluated in the CIE L ^* a ^* b ^* system using a Minolta Spectrophotometer CM3600D colorimeter. In this L ^* a ^* b ^* system, the three parameters denote, respectively, the colour intensity (L ^* ), the green/red colour axis (a ^* ) and the blue/yellow colour axis (b ^* ).

The colour build-up is represented by the colour difference ΔΕ between the non-dyed lock and the dyed lock: the greater the value of ΔΕ, the greater the colour build-up. This value is calculated from the following equation (i):

Δ E = (L ^* - L ₀ ^* ) ² + (a ^* - a ₀ ^* ) ² + (b ^* - b ₀ ^* ) ² _(j)

In this equation (i), L ^* , a ^* and b ^* represent the values measured on undyed locks of hair and L ₀ ^* , a ₀ ^* and b ₀ ^* represent the values measured on dyed locks of hair.

Table 1: L, a, b results and colour build-up with the compositions of the invention

The process of the invention makes it possible to obtain colourings that are very satisfactory in terms of colour build-up and power, despite the absence of chemical oxidizing agent.

For comparative purposes, when the locks were not treated with titanium salt, it was observed that the locks were significantly less coloured; this was corroborated by the colorimetric results below:

Table 2: Comparative L, a, b results and colour build-up without titanium salt

The locks treated with the process of the invention, which uses a titanium salt, are coloured more intensely and with significantly greater colour build-up than the locks treated with a process not using any titanium salt.

Example 2:

The following compositions were prepared (amounts in grams per 100 grams of composition):

Pretreatment composition Cii):

^■ Dye composition Ciii):

Protocol

The study relates to locks of natural Caucasian hair containing 90% white hairs (90 NW). According to a first treatment process P1 according to the invention, the locks are pretreated with composition Ci) comprising the titanium salt. During this pretreatment step, composition Ci) is left to stand for 45 minutes on each lock at 40°C, and each lock is then rinsed with running tap water and drained dry. The dye composition Cii) is then applied to each of the locks and left to stand for 45 minutes at 40°C.

In parallel, according to a second comparative treatment process P2 outside the invention, the locks are not pretreated with composition Ci), but are only moistened. The dye composition Cii) is then applied to each of the locks and left to stand for 45 minutes at 40°C.

After these leave-on times, the locks are washed with Elvive multivitamin shampoo, rinsed and then dried under a hood. Dyeing results

According to the process of the invention, i.e. with pretreatment with the titanium salts, very intensely coloured locks were obtained, whereas those which did not receive the pretreatment with titanium salts are weakly dyed. This is confirmed by the colorimetric measurements below. Table 3

It is clearly seen that the locks treated according to the process of the invention with composition Cii), then rinsed, and then with composition Ciii), are dyed much more intensely and with significantly greater colour build-up than the locks treated with the dye composition without pretreatment with the composition comprising the titanium salt, since the value of L ^* decreases greatly with the process according to the invention and the value of the colour build-up ΔΕ is higher according to the invention. Example 3:

The following compositions were prepared from the following ingredients in the following proportions, indicated in grams per 100 grams of composition: ^■ Pretreatment composition C(i): identical to that of Example 2 (composition Ci

1 ))

^■ Dye compositions C(ii): the three dye compositions C3, C4 and C5 below each comprising a different anionic direct dye were prepared:

Protocol

The study relates to locks of natural Caucasian hair containing 90% white hairs (90 NW).

According to a first dyeing process P1 according to the invention, three locks are pretreated with composition Ci) 1 comprising the titanium salt in a proportion of 3.33 g of composition per gram of hair. During this pretreatment step, composition Ci) is left to stand for 15 minutes on each lock at 40°C, and each lock is then rinsed with running tap water and drained dry. Each of the dye compositions Cii) 3, 4 and 5 is then applied separately to each of the three locks in a proportion of 3.33 g of composition per gram of hair and left to stand for 15 minutes at 40°C.

In parallel, according to a second comparative treatment process P2 outside the invention, the three different locks are not pretreated with composition Ci) 1 , but are preferably moistened. The dye compositions Cii) 3, 4 and 5 are then each applied separately to one of the three locks in a proportion of 3.33 g of composition per gram of hair and left to stand for 15 minutes at 40°C. According to this dyeing process, there is therefore no step of pretreating the locks with composition Ci) 1.

The following results are obtained according to the same evaluation protocol as that used in the preceding example.

It is clearly seen that the locks dyed according to the process of the invention with composition Ci) 1 , then rinsed and then with the dye compositions Cii) 3, 4 or 5 are dyed much more intensely and with significantly greater colour build-up than that obtained with the locks dyed according to the comparative process without pretreatment with composition Ci) 1 comprising the titanium salt, since the value of L decreases greatly according to the invention and the value of the colour build-up ΔΕ is higher according to the invention. Example 4:

The following compositions are prepared from the following ingredients in the following proportions, indicated in grams:

Pretreatment composition Cii) Composition Cii)

Ingredients

Glycolic acid 15 g

Dihydroxybis(ammonium lactato) titanium(IV) at 50% by weight 10.3 g

Cetyl hydroxyethylcellulose sold by Ashland under reference

NATROSOL PLUS 330 CS 1 -3 g

Copolymer acrylamide / acrylamido 2-methylpropane sodium

sulfonate in reverse emulsion at 40% in isoparaffin / water sold

by SEPPIC under the name SEPIGEL 305 2.5 g

Water qs 10Og

pH agent (hydrochloric acid) qs pH=2.2 ± 0.2

^■ Dve composition Ciii) :

Ingredients Composition Ciii)

Henna powder (LAWSONIA INERMIS NATURAL) sold by SM

Henna under reference HQ HENNA 12.5 g

Indigo powder (INDIGOFERA TINCTORIA LEAF) sold by

KANCOR under reference HQ INDIGO 12.5 g

Water at 40°C qs 100g

Protocol

The study relates to locks of natural Caucasian hair containing 90% white hairs (90 NW). According to a first treatment process P1 according to the invention, the locks are pretreated separately with composition Cii) comprising the titanium salt. During this pretreatment step, composition Cii) is left to stand for 15 minutes on each lock at 33°C, and each lock is then rinsed. The dye composition Ciii) is prepared just before use and then applied to each of the locks and left to stand for 60 minutes on each lock at 33°C. After these leave-on time the locks are rinsed and then dried under a hood.

In parallel, according to a second and a third comparative treatment processes P2 and P3 outside of the invention, the locks of natural Caucasian hair containing 90% white hairs (90 NW) are not pretreated with composition Cii).

The dye composition Ciii) is applied directly (without a pretreatment) to each of the locks and left to stand for 60 at 33°C (process P2) and for 120 minutes at 33°C (Process P3). After these leave-on times, the locks are rinsed and then dried under a hood.

Dyeing results

According to the process of the invention P1 , i.e. with pretreatment with the titanium salts, very intensely coloured locks were obtained, whereas those which did not receive the pretreatment with titanium salts are less intensely dyed, even with a leave on time of 120 minutes. This is confirmed by the colorimetric measurements below. Table 4

It is clearly seen that the locks treated according to the process of the invention P1 with a pretreatment with composition Cii) and then dyed with composition Ciii) are much more intensely dyed and with significantly greater colour build-up than the locks treated with the comparative processes P2 and P3, ie with the dye composition Ciii), with a leave-on time of 60 mn or even 120 mn, without pretreatment with the composition Cii) comprising the titanium salt, since the value of L ^* decreases greatly with the process according to the invention and the value of the colour build-up ΔΕ is higher according to the invention.