COMPOSITION FOR DYEING KERATIN FIBRES, COMPRISING AN ELECTROPHILIC MONOMER, A HYDROPHOBIC DIRECT DYE AND A

LIQUID ORGANIC SOLVENT

The present invention relates to a composition for dyeing keratin fibres, and in particular human keratin fibres such as the hair, comprising at least one electrophilic monomer, at least one hydrophobic direct dye that is soluble in the composition, the logP of which is greater than 2, and at least one liquid organic solvent.

It has been sought for a long time to modify the colour of the hair and in particular to mask grey hair. Several techniques have been developed to do this.

It is known practice to dye keratin fibres, and in particular human keratin fibres such as the 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, which are coloured and colouring molecules with affinity for keratin fibres, are applied for a time necessary to obtain the desired coloration, and are then rinsed out .

The colorations resulting therefrom are particularly chromatic colorations, but are, however, temporary or semi -permanent since the nature of the interactions that bind the direct dyes to the keratin fibre, and their desorption from the surface and/or the core of the fibre, are responsible for their low dyeing power and their poor wash-fastness or perspiration-fastness.

Moreover, it is known practice to dye keratin fibres

permanently by oxidation dyeing. This dyeing technique consists in applying to keratin fibres a composition containing dye precursors such as oxidation bases and couplers. Under the action of an oxidizing agent, these precursors form one or more coloured species on the hair .

The variety of molecules used as oxidation bases and couplers allows a wide range of colours to be obtained. The colorations resulting therefrom are permanent, powerful and resistant to external agents, especially to light, bad weather, perspiration and rubbing. However, this type of coloration results in degradation of the fibre due to the use of an oxidizing agent.

Hair treatment compositions using compositions comprising electrophilic monomers are also known from patent application FR 2 833 489. Such a composition allows perfectly coated and individualized hair to be obtained.

There is still a need to develop novel direct dye compositions for obtaining varied shades, in particular pastel shades, and which show good fastness, especially to external agents such as light, shampoo and sweat, while at the same time preserving the quality of the keratin fibres. In particular, there is a need to develop dye compositions for obtaining colorations that have a fastness close to that of oxidation dyeing, without the drawbacks associated with the presence of an oxidizing agent.

This aim is achieved with the present invention, one subject of which is a composition for dyeing keratin fibres, comprising at least one electrophilic monomer, at least one hydrophobic direct dye that is soluble in the composition, the logP of which is greater than 2, and at least one liquid organic solvent.

The composition of the invention allows varied shades and strong colorations to be obtained. Furthermore, the coloration obtained is very resistant to external agents, and especially to repeated washing.

The hair moreover shows good cosmetic properties, in particular remaining perfectly individualized and being easy to style.

A subject of the present invention is also a process for dyeing keratin fibres that comprises the application to the keratin fibres of the composition of the invention, and also the use of the composition of the invention for dyeing keratin fibres, in particular human keratin fibres such as the hair.

Another subject of the invention concerns a kit comprising an electrophilic monomer, a hydrophobic direct dye whose logP is greater than 2, and a liquid organic solvent.

The electrophilic monomer (s) present in the composition of the invention may be chosen from:

• the benzylidene malononitrile derivatives (A), 2- (4-chloro-benzylidene) malononitrile (Al), ethyl 2- cyano-3-phenylacrylate (B), and ethyl 2-cyano-3- (4- chlorophenyl) acrylate (Bl) described in Sayyah, J. Polymer Research, 2000, p. 97:

• methylidenemalonate derivatives, for instance:

• diethyl 2-methylenemalonate (C) described in Hopff, Makromoleculare Chemie [Macromolecular Chemistry] , 1961, p. 95, De Keyser, J. Pharm. Sci,

1991, p. 67 and Klemarczyk, Polymer, 1998, p. 173

(C)

• ethyl 2-ethoxycarbonylmethylenecarbonylacrylate (D) described in Breton, Biomaterials, 1998, p. 271 and Couvreur, Pharmaceutical Research, 1994, p. 1270:

• itaconate and itaconimide derivatives, for instance:

• dimethyl itaconate (E) described in Bachrach, European Polymer Journal, 1976, p. 563:

(E)

• N-butyl itaconimide (F), N- (4-tolyl) itaconimide

(G), N- (2-ethylphenyl) itaconimide (H), N- (2,6- diethylphenyl) itaconimide (I) , described in Wanatabe, J. Polymer Science: Part A: Polymer chemistry, 1994, p. 2073:

R = Bu (F), 4-tolyl (G), 2-ethylphenyl (H), 2,6- diethylphenyl (I) • the derivatives methyl α- (methylsulfonyl) acrylate

(K), ethyl α- (methylsulfonyl) acrylate (L), methyl α- (tert-butylsulfonyl) acrylate (M), tert-butyl α- (methyl - sulfonyl) acrylate (N) and tert-butyl α- (tert- butylsulfonyl) acrylate (0), described in Gipstein, J. Org. Chem, 1980, p. 1486 and the derivatives 1, 1 -bis (methylsulfonyl) ethylene (P) , 1 -acetyl -1-methylsulfonylethylene (Q) , methyl α- (methylsulfonyl) vinylsulfonate (R) and α-methylsul- fonylacrylonitrile (S), in patent US 2 748 050:

• the methyl vinyl sulfone (T) and phenyl vinyl sulfone (U) derivatives described in Boor, J. Polymer Science, 1971, p. 249:

-^SO ₂ Me ^SO ₂ Ph (T) (U)

• the phenyl vinyl sulfoxide derivative (V) described in Kanga, Polymer preprints (ACS, Division of Polymer Chemistry) , 1987, p. 322:

.Ph

0 (V)

• the derivative 3 -methyl -N- (phenylsulfonyl) -1-aza- 1 , 3 -butadiene (W) described in Bonner, Polymer Bulletin, 1992, p. 517:

•acrylate and acrylamide derivatives, for instance:

• N-propyl-N- (3-triisopropoxysilylpropyl) acrylamide (X) and N-propyl-N- (3-triethoxysilylpropyl) acrylamide (Y) described in Kobayashi, Journal of Polymer Science, Part A: Polymer Chemistry, 2005, p. 2754:

• 2 -hydroxyethyl acrylate ( Z ) and 2 -hydroxyethyl methacrylate (AA.) by Rozenberg , International Journal of Plasti cs Technology, 2003 , p . 17 :

• N-butyl acrylate (AB) described in Schmitt, Macromolecules, 2001, p. 2115, and

• tert-butyl acrylate (AC) described in Ishizone, Macromolecules, 1999, p. 955:

The electron-withdrawing monomer that is useful in the present invention may be cyclic or linear. When it is cyclic, the electron-withdrawing group is preferably exocyclic, i.e. it does not form an integral part of the cyclic structure of the monomer.

According to one particular embodiment, these monomers contain at least two electron-withdrawing groups.

As examples of monomers containing at least two electron-withdrawing groups, mention may be made of the monomers of formula (I) :

R1 R3

R2 R4 _(I) in which:

• Rl and R2 denote, independently of each other, a sparingly or non-electron-withdrawing group (sparingly or non-inductive-withdrawing) such as:

- a hydrogen atom,

- a saturated or unsaturated, linear, branched or cyclic hydrocarbon-based group preferably containing from 1 to 20 and better still from 1 to 10 carbon atoms, and optionally containing one or more nitrogen, oxygen or sulfur atoms, and optionally substituted with one or more groups chosen from -OR, -COOR, -COR, -SH, -SR and -OH, and halogen atoms, - a modified or unmodified polyorganosiloxane residue,

- a polyoxyalkylene group,

• R3 and R4 denote, independently of each other, an electron-withdrawing (or inductive-withdrawing) group preferably chosen from -N(R) ₃ ⁺ , -S(R) ₂ ⁺ , -SH ₂ ⁺ , -NH ₃ ⁺ , -NO ₂ , -SO ₂ R, -C≡N, -COOH, -COOR, -COSR, -CONH ₂ , -CONHR, -F, -Cl, -Br, -I, -OR, -COR, -SH, -SR and -OH groups, linear or branched alkenyl groups, linear or branched alkynyl groups, Ci-C ₄ mono- or polyfluoroalkyl groups, aryl groups such as phenyl, or aryloxy groups such as phenoxyloxy,

• R denotes a saturated or unsaturated, linear, branched or cyclic hydrocarbon-based group preferably containing from 1 to 20 and better still from 1 to 10 carbon atoms, and optionally containing one or more nitrogen, oxygen or sulfur atoms, and optionally substituted with one or more groups chosen from -OR' ,

-COOR', -COR', -SH, -SR' and -OH, halogen atoms, or a polymer residue, this polymer possibly being obtained by free-radical polymerization, by polycondensation or by ring opening, and R' denoting a Ci-Ci ₀ alkyl group.

The term "electron-withdrawing or inductive-withdrawing group (-1)" means any group that is more electronegative than carbon. Reference may be made to the publication P. R. Wells, Prog. Phys . Org . Chem. , VoI 6, 111 (1968) .

The term "sparingly or non-electron-withdrawing group" means any group whose electronegativity is less than or equal to that of carbon.

The alkenyl or alkynyl groups preferably contain from 2 to 20 carbon atoms and better still from 2 to 10 carbon atoms .

As saturated or unsaturated, linear, branched or cyclic hydrocarbon-based groups preferably containing from 1 to 20 carbon atoms, mention may be made especially of linear or branched alkyl, alkenyl or alkynyl groups, such as methyl, ethyl, n-butyl, tert-butyl, isobutyl, pentyl, hexyl , octyl, butenyl or butynyl ; cycloalkyl or aromatic groups.

Examples of substituted hydrocarbon-based groups that may be mentioned include hydroxyalkyl and polyhaloalkyl groups.

Examples of unmodified polyorganosiloxanes that may especially be mentioned include polyalkylsiloxanes such as polydimethylsiloxanes, polyarylsiloxanes such as polyphenylsiloxanes, and polyarylalkylsiloxanes such as polymethylphenylsiloxanes .

Among the modified polyorganosiloxanes that may especially be mentioned are polydimethylsiloxanes

containing polyoxyalkylene and/or siloxy and/or silanol and/or amine and/or imine and/or fluoroalkyl groups.

Among the polyoxyalkylene groups that may especially be mentioned are polyoxyethylene groups and polyoxypropylene groups preferably containing 1 to 200 oxyalkylene units.

Among the mono- or polyfluoroalkyl groups that may especially be mentioned are groups such as - (CH ₂ ) _n - (CF ₂ ) _m -CF ₃ or - (CH ₂ ) _n - (CF ₂ ) _m -CHF ₂ with n = 1 to 20 and m = 1 to 20.

The substituents Rl to R4 may optionally be substituted with a group having cosmetic activity. The cosmetic activities that are particularly used are obtained from groups having colouring, antioxidant, UV- screening and conditioning functions.

As examples of groups having a colouring function, mention may be made especially of azo, quinone, methine, cyanomethine and triarylmethane groups.

As examples of groups having an antioxidant function, mention may be made especially of groups of butylhydroxyanisole (BHA) , butylhydroxytoluene (BHT) or vitamin E type.

As examples of groups having a UV- screening function, mention may be made especially of groups of the benzophenone, cinnamate, benzoate, benzylidenecamphor and dibenzoylmethane type .

As examples of groups having a conditioning function, mention may be made especially of cationic groups and groups of fatty ester type.

Among the monomers mentioned above, the ones that are preferred are the monomers of the cyanoacrylate family

and the derivatives thereof of formula (II) :

in which:

• X denotes NH, S or 0, • Rl and R2 have the same meanings as above and preferably Rl and R2 represent a hydrogen atom,

• R' 3 represents a hydrogen atom or R as defined in formula (I) .

Preferably, X denotes 0.

Compounds of formula (II) that may be mentioned include the monomers : a) belonging to the family of polyfluoroalkyl 2-cyanoacrylates such as the ester 2,2,3,3- tetrafluoropropyl 2-cyano-2-propenoate of formula

(III) :

or the ester 2 , 2 , 2 - tri f luoroethyl 2 - cyano- 2 - propenoate of formula ( IV) :

b) the alkyl, alkenyl or alkoxyalkyl 2- cyanoacrylates of formula (VI) :

in which:

• Rl and R2 are as defined above,

• R' 3 represents a Ci-Ci ₀ alkyl, C ₂ -Ci ₀ alkenyl or (Ci- C ₄ ) alkoxy (Ci-Ci ₀ ) alkyl radical.

Mention may be made more particularly of ethyl 2-cyanoacrylate, methyl 2-cyanoacrylate, n-propyl 2- cyanoacrylate, isopropyl 2-cyanoacrylate, tert-butyl 2- cyanoacrylate, n-butyl 2-cyanoacrylate, isobutyl 2- cyanoacrylate, 3-methoxybutyl cyanoacrylate, n-decyl cyanoacrylate, hexyl 2-cyanoacrylate, 2-ethoxyethyl 2- cyanoacrylate, 2-methoxyethyl 2-cyanoacrylate, 2-octyl 2-cyanoacrylate, 2-propoxyethyl 2-cyanoacrylate, n- octyl 2-cyanoacrylate, allyl 2-cyanoacrylate, methoxy- propyl 2-cyanoacrylate and isoamyl cyanoacrylate.

In the context of the present invention, it is preferred to use the monomers defined in b) . According to one preferred embodiment, the cyanoacrylate monomer (s) is (are) chosen from C ₆ -Ci ₀ alkyl cyanoacrylates .

The monomers that are particularly preferred are the octyl cyanoacrylates of formula (VII) and mixtures thereof :

in which R' 3 is chosen from the following radicals:

-CH ₂ -CH (C ₂ H ₅ ) - (CH ₂ ) ₃ -CH ₃ ; - (CH ₂ ) ₅ -CH(CH ₃ ) -CH ₃ ; -(CH ₂ K-CH(C ₂ H ₅ ) -CH ₃ .

The monomers used in accordance with the invention may be covalently bonded to supports such as polymers, oligomers or dendrimers . The polymer or the oligomer may be linear, branched, in comb form or in block form. The distribution of the monomers of the invention over the polymeric, oligomeric or dendritic structure may be random, in an end position or in the form of blocks.

In the composition of the invention, the amount of electrophilic monomers may be between 0.1% and 80% by weight and preferably between 0.2% and 60% by weight relative to the total weight of the composition.

In the context of the invention, the electrophilic monomers are monomers capable of undergoing anionic polymerization in the presence of a nucleophilic agent. The term "anionic polymerization" means the mechanism defined in the book "Advanced Organic Chemistry", Third Edition by Jerry March, pages 151 to 161.

The nucleophilic agents capable of initiating the anionic polymerization are systems that are known per se, which are capable of generating a carbanion on contact with a nucleophilic agent, such as the hydroxide ions contained in water. The term "carbanion" means the chemical species defined in "Advanced Organic Chemistry", Third Edition, by Jerry March, page 141.

The nucleophilic agents may be applied independently of the composition of the invention. They may also be added to the composition of the invention at the time of use .

The nucleophilic agent is a molecular compound, an oligomer, a dendrimer or a polymer containing nucleophilic functions. In a non-limiting manner, nucleophilic functions that may be mentioned include the following functions: R ₂ N ^" , NH ₂ ^" , Ph ₃ C ^" , R ₃ C ^" , PhNH ^" , pyridine, ArS ^" , R-C≡C ^" , RS ^" , SH ^" , RO ^" , R ₂ NH, ArO ^" , N ₃ ^" , OH ^" , ArNH ₂ , NH ₃ , I ^" , Br ^" , Cl ^" , RCOO ^" , SCN ^" , ROH, RSH, NCO ^" , CN ^" , NO ₃ ^" , ClO ₄ ^" and H ₂ O, Ph representing a phenyl group,- Ar representing an aryl group and R representing a Ci-Cio alkyl group.

The electrophilic monomers may be synthesized according to the known methods described in the art . In particular, the cyanoacrylate monomers may be

synthesized according to the teaching of US 3 527 224, US 3 591 767, US 3 667 472, US 3 995 641, US 4 035 334 and US 4 650 826.

In the context of the invention, the hydrophobic dye is defined by the value of logP. This value of logP conventionally represents the partition coefficient of the dye between octanol and water. The value of logP may be calculated according to the method described in the article by Meylan and Howard "Atom/Fragment contribution method for estimating octanol-water partition coefficient" , J. Pharm. Sci . , 84: 83-92, 1995. This value may also be calculated using many commercially available software packages that determine the value of logP as a function of the structure of a molecule. By way of example, mention may be made of the Epiwinn version 3.11 software from the United States Environmental Agency, which was used in the present invention .

The direct dyes that may be used in the composition of the invention are hydrophobic dyes known in the art, which have a logP of greater than 2. Examples that may be mentioned include:

Disperse Blue 148 4.81

Disperse Violet 63 5.30

Disperse Blue 60 3.38

Soivent Orange 15 3.90

According to one particular embodiment, at least one of the hydrophobic direct dyes that are useful in the context of the invention has a logP of greater than 4.

According to another particular embodiment, at least one of the hydrophobic direct dyes that are useful in the context of the invention has a logP of greater than 6.

According to the present invention, the hydrophobic direct dye(s) is (are) soluble in the composition to at least 0.5 gram per litre and preferably to at least 1 gram per litre at a temperature of 25 ⁰ C.

The hydrophobic direct dye(s) whose logP is greater than 2 may be present in the composition in an amount of between 0.001% and 5% by weight approximately relative to the total weight of the composition.

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

The organic solvent (s) that is (are) useful in the context of the invention is (are) chosen from compounds that are liquid at a temperature of 25 ⁰ C and at a pressure of 105 Pa (760 mmHg) and are different from the electrophilic monomers that are useful in the context of the invention.

The organic solvent (s) is (are) chosen, for example, from aromatic alcohols such as benzyl alcohol, phenoxyethanol or phenylethyl alcohol; liquid fatty alcohols, especially of Ci ₀ -C ₃₀ ; Ci-C ₆ alkanols such as ethanol, isopropanol, n-propanol, butanol, n-pentanol, 1, 2 -propanediol, 1 , 3 -propanediol , l-methoxy-2-propanol , l-ethoxy-2-propanediol , 1,3- and 1 , 4-butanediol , and 1, 2-hexanediol; polyols and polyol ethers with a free -OH function, such as 2-butoxyethanol , propylene glycol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether and monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, neopentyl glycol, isoprene glycol, glycerol, glycol, dipropylene glycol, butylene glycol or butyl diglycol ; volatile silicones such as cyclopenta- siloxane, cyclohexasiloxane, polydimethylsiloxanes optionally modified with alkyl and/or amine and/or imine and/or fluoroalkyl and/or carboxylic and/or betaine and/or quaternary ammonium functions; modified liquid polydimethylsiloxanes; mineral, organic or plant oils,- alkanes and more particularly C ₅ -Ci ₀ alkanes; liquid fatty acids,- liquid fatty esters and more particularly liquid fatty alkyl benzoates or salicylates.

The organic solvent (s) is (are) preferably chosen from organic oils,- silicones such as volatile silicones, amino or non-amino silicone gums or oils, and mixtures

thereof; mineral oils,- plant oils such as olive oil, castor oil, rapeseed oil, coconut oil, wheatgerm oil, sweet almond oil, avocado oil, macadamia oil, apricot oil, safflower oil, candlenut oil, camelina oil, tamanu oil or lemon oil, or alternatively organic compounds such as C ₅ -Ci ₀ alkanes, acetone, methyl ethyl ketone, esters of liquid Ci-C ₂₀ acids and of Ci-C ₈ alcohols, such as methyl acetate, butyl acetate, ethyl acetate and isopropyl myristate, dimethoxyethane, diethoxy- ethane, liquid Ci ₀ -C ₃₀ fatty alcohols such as oleyl alcohol, liquid Ci ₀ -C ₃₀ fatty alkyl esters such as Ci ₀ -C ₃₀ fatty alkyl benzoates, and mixtures thereof; polybutene oil, isononyl isononanoate, isostearyl malate, penta- erythrityl tetraisostearate, tridecyl trimellitate, and the mixture of cyclopentasiloxane (14.7% by weight) /polydimethylsiloxane dihydroxylated in the α and ω positions (85.3% by weight), or mixtures thereof.

According to one preferred embodiment, the organic solvent (s) is (are) chosen from silicones such as liquid polydimethylsiloxanes and modified liquid polydimethylsiloxanes, their viscosity at 25 ⁰ C being between 0.1 cSt and 1 000 000 cSt and more preferentially between 1 cSt and 30 000 cSt .

Mention will preferably be made of the following oils: - the mixture of α, ω-dihydroxylated polydimethylsil- oxane/cyclopentadimethylsiloxane (14.7/85.3) sold by Dow Corning under the name DC 1501 Fluid; - the mixture of α, ω-dihydroxylated polydimethylsil- oxane/polydimethylsiloxane sold by Dow Corning under the name DC 1503 Fluid; the dimethicone/cyclopentadimethylsiloxane mixture sold by Dow Corning under the name DC 1411 Fluid or that sold by Bayer under the name SF 1214; the cyclopentadimethylsiloxane sold by Dow Corning under the name DC245 Fluid; and the respective mixtures of these oils.

The composition of the invention may contain, besides the liquid organic solvent (s), water. Preferably, the composition of the invention is anhydrous, i.e. it contains less than 1% by weight of water relative to the total weight of the composition.

The organic solvent (s) of the composition generally represent (s) from 0.01% to 99% and preferably from 50% to 99% by weight relative to the total weight of the composition.

The composition of the invention may also be in the form of an emulsion and/or may be encapsulated, the electrophilic monomers being maintained in an anhydrous medium until the time of use. When the composition is an emulsion, this emulsion consists, for example, of a dispersed or continuous phase that may consist of water, Ci-C ₄ aliphatic alcohols or mixtures thereof and an anhydrous organic phase comprising the monomer. In the case of capsules or microcapsules, the capsule may contain the monomer in an anhydrous medium and may be dispersed in an anhydrous medium as defined above, water or Ci-C ₄ aliphatic alcohols, or mixtures thereof.

Polymerization inhibitors and more particularly anionic and/or free-radical polymerization inhibitors may also be present in the composition of the invention, in order to enhance the stability of the composition over time. In a non-limiting manner, the following polymer- ization inhibitors may be mentioned: sulfur dioxide, nitric oxide, boron trifluoride, hydroquinone and derivatives thereof such as hydroquinone monoethyl ether, tert-butylhydroquinone (TBHQ) , benzoquinone and derivatives thereof such as duroquinone, catechol and derivatives thereof such as t-butylcatechol and methoxycatechol , anisole and derivatives thereof such as methoxyanisole or hydroxyanisole, pyrogallol and derivatives thereof, p-methoxyphenol, hydroxybutyl - toluene, alkyl sulfates, alkyl sulfites, alkyl

sulfones, alkyl sulfoxides, alkyl sulfides, mercaptans and 3-sulfonene, and mixtures thereof. The alkyl groups preferably denote groups containing 1 to 6 carbon atoms .

Mineral or organic acids may also be used as inhibitor.

Thus, the cosmetic composition according to the invention may also comprise at least one mineral or organic acid, this acid containing one or more carboxylic or sulfonic groups, with a pKa of between 0 and 6, such as phosphoric acid, hydrochloric acid, nitric acid, benzenesulfonic acid, toluenesulfonic acid, sulfuric acid, carbonic acid, hydrofluoric acid, acetic acid, formic acid, propionic acid, benzoic acid, mono-, di- or trichloroacetic acid, salicylic acid, trifluoroacetic acid, octanoic acid, heptanoic acid and hexanoic acid.

Acetic acid is preferably used.

The concentration of inhibitor in the cosmetic composition of the invention may be between 10 ppm and 30% by weight and more preferentially between 10 ppm and 15% by weight relative to the total weight of the composition.

The composition may also comprise one or more agents for reducing the disulfide bridges of which keratin is partly composed. In a non-exhaustive manner, examples that may be mentioned include the following compounds: anhydrous sodium thiosulfate, powdered sodium metabisulfite, thiourea, - ammonium sulfite, thioglycolic acid, thiolactic acid, ammonium thiolactate, glyceryl monothioglycolate,

ammonium thioglycolate, thioglycerol ,

2, 5-dihydroxybenzoic acid, diammonium dithioglycolate, - strontium thioglycolate, calcium thioglycolate, zinc formosulfoxylate, isooctyl thioglycolate, dl-cysteine, - monoethanolamine thioglycolate.

The composition of the invention may also contain one or more polymers with no reactivity on the electrophilic monomers and which is (are) capable of increasing the viscosity of the composition. Increasing the viscosity makes it possible to reduce the rate of polymerization of the electrophilic monomers. To do this, it is possible to add to the composition of the invention, in a non-exhaustive manner, polymethyl methacrylate (PMMA) or cyanoacrylate-based copolymers as described in patent US 6 224 622.

The composition in accordance with the invention may also contain at least one agent usually used in cosmetics chosen from, for instance, reducing agents, fatty substances, plasticizers, softeners, antifoams, moisturizers, pigments, clays, mineral fillers, UV- screening agents, mineral colloids, peptizers, solubilizing agents, fragrances, preserving agents, anionic, cationic, nonionic or amphoteric surfactants, fixing or non- fixing polymers, proteins, vitamins, direct dyes other than the hydrophobic dyes of the invention, oxidation dyes, nacreous agents, propellent gases, mineral or organic thickeners such as benzylidene sorbitol and N-acylamino acids, oxyethylenated or non-oxyethylenated waxes, paraffins, Ci ₀ -C ₃₀ fatty acids such as stearic acid, lauric acid, Ci ₀ -C ₃₀ fatty amides such as lauric diethanolamide, Ci ₀ - C ₃₀ fatty alkyl esters such as Ci ₀ -C ₃₀ fatty alkyl

benzoates, and mixtures thereof.

This composition may be in various forms, such as lotions, sprays or mousses, and may be applied in the form of shampoos or hair conditioners.

In the case of sprays, the composition of the invention may contain a propellant. The propellant consists of the compressed or liquefied gases usually used for the preparation of aerosol compositions. Air, carbon dioxide, compressed nitrogen or a soluble gas such as dimethyl ether, halogenated (in particular fluorinated) or non-halogenated hydrocarbons, and mixtures thereof, will preferentially be used.

According to the process of the invention, the composition of the invention is applied to the keratin fibres, in particular human keratin fibres such as the hair, in the presence of a nucleophilic agent.

According to one variant, the composition in accordance with the invention is applied to the keratin fibres in two steps: a step that consists in applying a composition comprising the hydrophobic direct dye(s), and a step that consists in applying a composition comprising the electrophilic monomer (s), one of the two compositions or both of them comprising the liquid organic solvent (s) .

According to one particular embodiment of the process of the invention, the nucleophilic agent capable of initiating the polymerization of the electrophilic monomer, especially a cyanoacrylate monomer, may be applied beforehand to the keratin fibres. The nucleophilic agent may be used pure, as a solution, in the form of an emulsion or may be encapsulated. It may also be added to the anhydrous composition at the time of use just before application to the keratin fibres.

Preferably, this nucleophilic agent is water. This water may be supplied, for example, by premoistening the keratin fibres. It may also be added directly to the composition before application.

According to one particular embodiment, it is possible to modify the polymerization kinetics by premoistening the fibre with an aqueous solution whose pH has been adjusted using a base, an acid or an acid/base mixture. The acid and/or the base may be mineral or organic.

According to one variant, the process of the invention may be performed in several steps: a first step that consists in applying a composition containing the hydrophobic direct dye(s) to the fibres, and a second step that consists in applying a composition containing the electrophilic monomer (s) and the liquid organic solvent (s), the nucleophilic agent being present in the composition containing the hydrophobic direct dye or in a separate composition.

According to this variant, the composition containing the hydrophobic direct dye(s) is preferably an aqueous solution in which the hydrophobic direct dye(s) is (are) soluble, which allows moistening of the fibre and initiation of polymerization when the cyanoacrylate monomer is applied.

According to another variant, the process of the invention may be performed in several steps: a first step that consists in applying a composition containing the electrophilic monomer (s) and the liquid organic solvent (s) to the fibres that have been premoistened with an aqueous solution, and a second step that consists in applying a composition containing the hydrophobic direct dye(s) .

According to the process of the invention, a preferred embodiment consists in applying the electrophilic

monomer, the liquid organic solvent and the hydrophobic direct dyes from the same composition.

The process of the invention may comprise additional intermediate or final steps such as the application of a cosmetic product, a rinsing step or a drying step. The drying may be performed under a hood, with a hairdryer and/or with a smoothing iron. In particular, the application of the compositions in accordance with the invention may be followed by rinsing.

It is also possible to perform multiple applications of the composition of the invention in order to obtain a superposition of coats to achieve specific properties of the deposit in terms of chemical nature, mechanical strength, thickness, appearance or feel.

In order to improve, inter alia, the adhesion of the poly (cyanoacrylate) formed in situ, the fibre may be pretreated with polymers of any type.

To modify the anionic polymerization kinetics, it is also possible to increase the nucleophilicity of the fibre via chemical transformation of the keratin fibres. An example that may be mentioned is the reduction of the disulfide bridges of which keratin is partly composed, into thiols, before applying the composition of the invention using reducing agents such as those defined previously.

The application of the composition of the invention may also be preceded by a hair treatment such as direct dyeing or oxidation dyeing.

A subject of the invention is also a dyeing kit comprising a first composition that contains the hydrophobic direct dye(s), a second composition that contains the electrophilic monomer (s), one of the two compositions or both of them comprising the organic solvent (s), and optionally a third composition that

contains the nucleophilic agent.

According to one variant, the kit comprises a first anhydrous composition that comprises at least the hydrophobic direct dye(s), the liquid organic solvent and the electrophilic monomer (s), and a second composition that comprises a nucleophilic agent.

The non-limiting examples that follow illustrate the invention without limiting its scope.

EXAMPLES

Example 1

The following composition is prepared:

0.5 g of this composition is applied to a 1 g lock of clean, wet natural grey hair containing 90% white hairs. After a leave-on time of 15 minutes at room temperature, the lock is dried with a hairdryer for 2 minutes .

The lock is dyed blue and the coloration obtained is resistant to at least one shampoo wash.

Example 2

The following composition is prepared:

0.5 g of this composition is applied to a 1 g lock of clean, wet natural grey hair containing 90% white hairs. After a leave-on time of 15 minutes at room temperature, the lock is dried with a hairdryer for 2 minutes .

The lock is dyed yellow and the coloration obtained is resistant to at least one shampoo wash.

Example 3

The following composition is prepared:

0.5 g of this composition is applied to a 1 g lock of clean, wet natural grey hair containing 90% white hairs. After a leave-on time of 15 minutes at room temperature, the lock is dried with a hairdryer for 2

minutes

The lock is dyed orange and the coloration obtained is resistant to at least one shampoo wash.

Example 4

The following composition is prepared:

0.5 g of this composition is applied to a 1 g lock of clean, wet natural grey hair containing 90% white hairs. After a leave-on time of 15 minutes at room temperature, the lock is dried with a hairdryer for 2 minutes .

The lock is dyed red and the coloration obtained is resistant to at least one shampoo wash.