DESCRIPTION

TITLE: METHOD FOR THE TREATMENT OF KERATIN FIBRES BY MEANS OF A COMPOSITION CONTAINING ARGININE AND OF AN OXIDIZING COMPOSITION

A subject-matter of the present application is a method for the treatment of keratin fibres, in particular human keratin fibres, such as the hair, starting from an arginine-comprising composition and from a separate oxidizing composition comprising one or more chemical oxidizing agents and one or more acrylic anionic associative polymers.

It is known practice to dye or to bleach keratin fibres, and in particular human hair, with dyeing compositions containing oxidizing agents, alkaline agents and optionally oxidation dye precursors, such as oxidation bases, in particular ortho- or para-phenylenediamines, ortho- or para-aminophenols and heterocyclic compounds. These oxidation bases are colourless or weakly coloured compounds which, when combined with oxidizing products, can give rise to coloured compounds by a process of oxidative condensation.

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

The variety of the molecules employed as oxidation bases and couplers makes it possible to obtain a rich palette of colours.

In the field of hair dyeing, there still exists a need to develop still more effective dyeing compositions. In particular, there still exists a need to employ, in the dyeing/bleaching method, compositions exhibiting good use qualities, in particular alkaline and oxidizing compositions which readily mix in order to result in a homogeneous ready-for-use composition which is easy to spread over the hair, without risk of running. Furthermore, there is a search to employ compositions which make it possible to reduce unpleasant odours during use, to minimize detrimental changes to keratin fibres or problems of comfort on the scalp, while maintaining a good level of dyeing effectiveness.

Thus, the method should also make it possible to dye keratin fibres in an intense, persistent, sparingly selective and chromatic manner, with good build-up of the colour, and be capable of resulting in colourings which are resistant to the various attacks to which the fibres may be subjected, such as bad weather, washing and perspiration.

These aims are achieved with the present invention, a subject-matter of which is in particular a method for the treatment of keratin fibres, especially human keratin fibres, such as the hair, comprising: a. at least one step of preparation of a composition M comprising the mixing: i. of at least one composition A comprising arginine; with ii. at least one oxidizing composition B separate from the composition A comprising:

- one or more chemical oxidizing agents, and

- one or more acrylic anionic associative polymers, then b. at least one step of application, to said keratin fibres, of said composition M.

It has been found that the treatment method according to the invention makes it possible to dye keratin fibres satisfactorily, in particular resulting in powerful, persistent, chromatic and sparingly selective colourings, and/or colourings with a good colour build-up.

Furthermore, the method according to the invention results in colourings which are resistant to the various attacks to which keratin fibres may be subjected, such as bad weather, light, washing and/or perspiration.

The compositions employed in the treatment method according to the invention exhibit good use qualities; in particular, the alkaline and oxidizing compositions readily mix and result in a homogeneous ready-for-use composition which is easy to spread over the hair, without risk of running. Furthermore, these compositions make it possible to reduce unpleasant odours during use and to minimize detrimental changes to keratin fibres, while maintaining a good level of effectiveness.

This method of the invention is particularly advantageous when it is combined with oxidation dyes in the form of a powder, indeed even of beads of oxidation dyes, each containing preferably a single oxidation base or oxidation coupler. This is because the method according to the invention then makes it possible to use a specific dyeing composition containing precise contents of oxidation dye precursors specifically chosen in order to obtain exactly the hue desired by the user.

Thus, when the method of the invention is employed with a multitude of beads of oxidation dyes each containing a single oxidation dye, it makes it possible to combine a very large number of different oxidation precursors, at different respective contents, and thus to colour the keratin fibres according to a very broad range of possible colours, while taking into account the nature and the state of said fibres.

Moreover, the method according to this embodiment makes it possible to give a dyeing result which is perfectly reproducible from one occasion to the other.

Another subject-matter of the invention is a method for the preparation of a dyeing composition for the dyeing of keratin fibres, in particular human keratin fibres, such as the hair, comprising the mixing: a. of several solid particles, which are identical or different, each containing one or more oxidation dye precursors; with b. at least one composition A comprising arginine; and c. at least one oxidizing composition B separate from the composition A comprising: i) one or more chemical oxidizing agents, and ii) one or more acrylic anionic associative polymers.

Another subject-matter of the invention is the use of said composition for the treatment, preferably the dyeing/bleaching, of keratin fibres, in particular human keratin fibres, such as the hair.

Another subject-matter of the invention is a composition M' for the treatment, preferably dyeing/bleaching, of keratin fibres, in particular human keratin fibres, such as the hair, comprising arginine, one or more chemical oxidants and one or more acrylic anionic associative polymers, and optionally one or more oxidation dye precursors.

Other subject-matters, characteristics, aspects and advantages of the invention will become even more clearly apparent on reading the description and the example which follows.

In the present description, and unless otherwise indicated:

- the expression "at least one" is equivalent to the expression "one or more" and can be replaced therewith;

- the expression "between" is equivalent to the expression "ranging from" and can be replaced therewith, and implies that the limits are included;

- the term "keratin fibres", according to the present patent application, preferably denotes human keratin fibres and more particularly the hair. The treatment method of the invention is preferably a method for dyeing/bleaching keratin fibres.

The oxidation dye precursors

When the treatment method according to the invention is a method for dyeing keratin fibres, the step of preparation of the composition M comprises the mixing with one or more oxidation dye precursors.

According to a preferred embodiment of the invention, the oxidation dye precursor(s) is (are) introduced in the form of solid particles, which are identical or different, each containing one or more oxidation dye precursors.

According to this embodiment, said precursors can be identical or different from one solid particle to the other.

It is found, for this embodiment, that the solid particles each containing a single dose of oxidation dye precursor exhibit a very good stability on storage. Furthermore, when the solid particles are employed in the method of the invention, they rapidly disintegrate and readily and rapidly result in a homogeneous mixture with the aqueous compositions employed in the method.

Preferably, said solid particles comprise:

- one or more solid particles of a first type PI containing a single oxidation dye precursor Cl; and

- one or more solid particles of a second type P2 containing a single oxidation dye precursor C2; it being understood that the oxidation dye precursor C 1 is different from the oxidation dye precursor C2.

Step a. of preparation of a composition M according to the invention thus comprises, preferably, the mixing:

- of one or more solid particles of a first type PI containing a single oxidation dye precursor Cl; and

- of one or more solid particles of a second type P2 containing a single oxidation dye precursor C2; with

- at least one composition A comprising arginine; and

- at least one separate oxidizing composition B comprising one or more chemical oxidizing agents and one or more acrylic anionic associative polymers; it being understood that the oxidation dye precursor C 1 is different from the oxidation dye precursor C2.

Thus, according to this preference, at least two types of solid particles used in the method according to the invention do not comprise the same oxidation dye precursor.

More preferentially, each type of solid particle according to the invention comprises a single oxidation dye precursor in a content between 0.1% and 50% by weight, with respect to the total weight of the solid particle containing it.

According to a preferred embodiment, step a. of preparation of a composition M additionally comprises the mixing with one or more solid particles of a third type P3, containing a single oxidation dye precursor C3 different from the dye precursors Cl and C2, more preferentially in a content between 0.1% and 50% by weight, with respect to the total weight of the solid particle(s) P3. It is thus possible to mix as many oxidation dye precursors as necessary, this being done in the respective proportions necessary in order to achieve the desired hue.

Thus, according to another preferred embodiment, step a. of preparation of a composition M comprises the mixing of n types of solid particles PI to Pn (with n representing an integer greater than or equal to 3, and preferably between 3 and 20, more preferentially between 3 and 15 and more preferentially still between 4 and 10), each type of solid particle PI to Pn containing a single oxidation dye precursor (respectively Cl to Cn), more preferentially in a content between 0.1% and 50% by weight, with respect to the total weight of the solid particles PI to Pn respectively, and it being understood that said precursors Cl to Cn are all different from one another.

According to a specific embodiment of the invention, the composition M additionally comprises the mixing of one or more solid particles of P'x type (with x representing an integer greater than or equal to 1, and in particular ranging from 1 to n with n as described above, and preferably between 1 and 20, more preferentially between 1 and 15, and more preferentially still between 1 and 10) containing a single oxidation dye precursor Cx, more preferentially in a content between 0.1% and 50% by weight, with respect to the total weight of the solid particle(s) of P'x type; said solid particle of P'x type corresponding to the solid particle Px described above, except for the content of oxidation dye precursor Cx. By way of example of this specific embodiment of the invention, the composition M can comprise the mixture:

(i) of one or more solid particles of a first type PI containing a single oxidation dye precursor Cl, preferably in a content of between 0.1% and 50% by weight, with respect to the total weight of the solid particle(s) of PI type;

(ii) of one or more solid particles of a second type P2 containing a single oxidation dye precursor C2, preferably in a content of between 0.1% and 50% by weight, with respect to the total weight of the solid particle(s) of P2 type; and

(iii) of one or more solid particles of P'l type containing only said oxidation dye precursor Cl, preferably in a content of between 0.1% and 50% by weight, with respect to the total weight of the solid particle(s) of P'l type; with

(iv) at least one composition A comprising arginine;

(v) at least one separate oxidizing composition B comprising one or more chemical oxidizing agents and one or more acrylic anionic associative polymers; it being understood that:

- the oxidation dye precursor Cl is different from the oxidation dye precursor C2;

- the content of oxidation dye precursor Cl contained in the solid particle(s) PI is different from the content of oxidation dye precursor Cl contained in the solid particle(s) P'l.

Preferably, the oxidation dye precursors, capable of being used generally in the method of the invention, and in particular of being contained in the solid particles, are chosen from oxidation bases and oxidation couplers, more preferentially from oxidation bases.

According to a preferred embodiment of the invention, the oxidation dye precursor Cl as defined above is chosen from oxidation bases and the oxidation dye precursor C2 as defined above is chosen from oxidation couplers (or vice versa).

By way of example, the oxidation bases are chosen from para- phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols, ortho- aminophenols, heterocyclic bases and the corresponding addition salts. Among the para-phenylenediamines which may be mentioned are, for example, para-phenylenediamine, para-toluenediamine, 2-chloro-para- phenylenediamine, 2,3-dimethyl-para-phenylenediamine, 2,6-dimethyl-para- phenylenediamine, 2,6-diethyl-para-phenylenediamine, 2,5-dimethyl-para- phenylenediamine, N,N-dimethyl-para-phenylenediamine, N,N -diethyl-para- phenylenediamine, N,N-dipropyl-para-phenylenediamine, 4-amino-N,N-diethyl-3- methylaniline, N,N-bis(P-hydroxyethyl)-para-phenylenediamine, 4-N,N-bis(P- hydroxyethyl)amino-2-methylaniline, 4-N,N-bis(P-hydroxyethyl)amino-2- chloroaniline, 2^-hydiOxycthy 1 -para-phony lcncdiaminc, 2-methoxymethyl-para- phenylenediamine, 2-fluoro-para-phenylenediamine, 2-isopropyl-para- phenylenediamine, N-(P-hydroxypropyl)-para-phenylenediamine, 2-hydroxymethyl- para-phenylenediamine, N,N-dimethyl-3-methyl-para-phenylenediamine, N-ethyl-N- (P-hydroxyethyl)-para-phenylenediamine, N-(P,Y-dihydroxypropyl)-para- phenylenediamine, N-(4'-aminophenyl)-para-phenylenediamine, N -phenyl-para- phenylenediamine, 2^-hydroxyethyloxy-para-phenylenediamine, 2-b- acetylaminoethyloxy-para-phenylenediamine, N-(P-methoxyethyl)-para- phenylenediamine, 4-aminophenylpyrrolidine, 2-thienyl-para-phenylenediamine, 2-b- hydroxyethylamino-5-aminotoluene and 3-hydroxy- l-(4'-aminophenyl)pyrrolidine, and the corresponding addition salts with an acid.

Among the para-phenylenediamines mentioned above, para- phenylenediamine, para-toluenediamine, 2-isopropyl-para-phenylenediamine, 2-b- hydroxyethyl-para-phenylenediamine, 2^-hydroxyethyloxy-para-phenylenediamine, 2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine, 2,3- dimethyl-para-phenylenediamine, N,N-bis(b-hydroxyethyl)-para-phenylenediamine, 2-chloro-para-phenylenediamine and 2^-acetylaminoethyloxy-para- phenylenediamine, and the corresponding addition salts with an acid, are particularly preferred.

Among the bis(phenyl)alkylenediamines which may be mentioned, for example, are N,N'-bis^-hydroxyethyl)-N,N'-bis(4'-aminophenyl)-l,3- diaminopropanol, N,N'-bi s^-hydroxy ethyl) -N,N'-bis(4'- aminophenyl)ethylenediamine, N,N'-bis(4-aminophenyl)tetramethylenediamine, N,N'-bis(b-hydroxyethyl)-N,N'-bis(4-aminophenyl)tetramethyle nediamine, N,N'- bis(4-methylaminophenyl)tetramethylenediamine, N,N'-bis(ethyl)-N,N'-bis(4'-amino- 3'-methylphenyl)ethylenediamine and l,8-bis(2,5-diaminophenoxy)-3,6-dioxaoctane, and the corresponding addition salts.

Among the para-aminophenols which are mentioned are, for example, para- aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol, 4-amino-3- chlorophenol, 4-amino-3-hydroxymethylphenol, 4-amino-2-methylphenol, 4-amino- 2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol, 4-amino-2- aminomethylphenol, 4-amino-2-(P-hydroxyethylaminomethyl)phenol and 4-amino-2- fluorophenol, and the corresponding addition salts with an acid.

Among the ortho-aminophenols which may be mentioned are, for example, 2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol and 5-acetamido- 2-aminophenol, and the corresponding addition salts.

Among the heterocyclic bases which may be mentioned are, for example, pyridine, pyrimidine and pyrazole derivatives.

Among the pyridine derivatives which may be mentioned are the compounds described, for example, in Patents GB 1 026978 and GB 1 153 196, for example 2,5- diaminopyridine, 2-(4-methoxyphenyl)amino-3-aminopyridine and 3,4- diaminopyridine, and the corresponding addition salts.

Other pyridine oxidation bases which are useful in the present invention are the 3-aminopyrazolo[l,5-a]pyridine oxidation bases or the corresponding addition salts described, for example, in Patent Application FR 2 801 308. Examples which may be mentioned comprise pyrazolo[l,5-a]pyrid-3-ylamine, 2-acetylaminopyrazolo[l,5- a]pyrid-3-ylamine, 2-morpholin-4-ylpyrazolo[l,5-a]pyrid-3-ylamine, 3- aminopyrazolo[l,5-a]pyridine-2-carboxylic acid, 2-methoxypyrazolo[l,5-a]pyrid-3- ylamine, (3-aminopyrazolo[l,5-a]pyrid-7-yl)methanol, 2-(3-aminopyrazolo[l,5- a]pyrid-5-yl)ethanol, 2-(3-aminopyrazolo[l,5-a]pyrid-7-yl)ethanol, (3- aminopyrazolo[l,5-a]pyrid-2-yl)methanol, 3,6-diaminopyrazolo[l,5-a]pyridine, 3,4- diaminopyrazolo [ 1 ,5-a]pyridine, pyrazolo [1,5- a]pyridine-3 ,7 -diamine, 7 -morpholin- 4-ylpyrazolo [ 1 ,5 -a]pyrid-3 -ylamine, pyrazolo [ 1 ,5-a]pyridine-3 ,5-diamine, 5 - morpholin-4-ylpyrazolo[l,5-a]pyrid-3-ylamine, 2-[(3-aminopyrazolo[l,5-a]pyrid-5- yl)(2-hydroxyethyl)amino]ethanol, 2-[(3-aminopyrazolo[l,5-a]pyrid-7-yl)(2- hydroxyethyl)amino] ethanol, 3 -aminopyrazolo [ 1 ,5-a]pyridin-5-ol, 3 - aminopyrazolo[l,5-a]pyridin-4-ol, 3-aminopyrazolo[l,5-a]pyridin-6-ol, 3- aminopyrazolo[l,5-a]pyridin-7-ol, 2-P-hydroxyethoxy-3-aminopyrazolo[l,5- a]pyridine; 2-(4-dimethylpiperazinium-l-yl)-3-aminopyrazolo[l,5-a]pyridi ne; and the corresponding addition salts.

More particularly, the oxidation bases which are useful in the present invention are chosen from 3-aminopyrazolo[l,5-a]pyridines and are preferably substituted on the carbon atom 2 by: a) a (di)(Ci-C ₆ )(alkyl)amino group, it being possible for said alkyl group to be substituted by at least one hydroxyl, amino or imidazolium group; b) an optionally cationic 5- to 7-membered heterocycloalkyl group comprising from 1 to 3 heteroatoms, optionally substituted by one or more (Ci-C ₆ )alkyl groups, such as a di(Ci-C4)alkylpiperazinium group; or c) a (Ci-C ₆ )alkoxy group optionally substituted by one or more hydroxyl groups, such as a b-hydroxyalkoxy group, and the corresponding addition salts.

The pyrimidine derivatives which may be mentioned include the compounds described, for example, in Patents DE 2359399, JP 88-169571, JP 05-63124 and EP 0 770375 or Patent Application WO 96/15765, such as 2,4,5,6-tetraaminopyrimidine, 4- hydroxy-2,5,6-triaminopyrimidine, 2-hydroxy-4,5,6-triaminopyrimidine, 2,4- dihydroxy-5,6-diaminopyrimidine, 2,5,6-triaminopyrimidine and their addition salts and their tautomeric forms, when a tautomeric equilibrium exists.

Among the pyrazole derivatives which may be mentioned are the compounds described in Patents DE 3843892 and DE 4133957 and Patent Applications WO 94/08969, WO 94/08970, FR A-2 733 749 and DE 195 43 988, such as 4,5-diamino- 1-methylpyrazole, 4,5-diamino- l-(P-hydroxyethyl)pyrazole, 3,4-diaminopyrazole,

4.5-diamino- l-(4'-chlorobenzyl)pyrazole, 4,5-diamino- 1,3-dimethylpyrazole, 4,5- diamino-3-methyl-l-phenylpyrazole, 4,5-diamino- 1 -methyl-3 -phenylpyrazole, 4- amino- 1 ,3-dimethyl-5-hydrazinopyrazole, 1 -benzyl-4, 5-diamino-3-methylpyrazole,

4.5-diamino-3-/ _<? r/-butyl- 1 -mcthylpyrazolc, 4,5-diamino- l-ieri-butyl-3- methylpyrazole, 4,5-diamino-l -(b-hydroxycthyl )-3- mcthylpyrazolc, 4,5-diamino- 1- ethyl-3-methylpyrazole, 4,5-diamino- 1 -ethyl-3 -(4'-methoxyphenyl)pyrazole, 4,5- diamino- 1 -ethyl-3 -hydro xymethylpyrazole, 4,5-diamino-3-hydroxymethyl-l- methylpyrazole, 4,5-diamino-3-hydroxymethyl- 1-isopropylpyrazole, 4,5-diamino-3- methyl-l-isopropylpyrazole, 4-amino-5-(2'-aminoethyl)amino- 1,3-dimethylpyrazole,

3.4.5-triaminopyrazole, l-methyl-3,4,5-triaminopyrazole, 3,5-diamino- l-methyl-4- methylaminopyrazole and 3,5-diamino-4-^-hydroxyethyl)amino- 1-methylpyrazole, and the corresponding addition salts. Use may also be made of 4,5-diamino- 1-(b- methoxyethyl)pyrazole.

A 4,5-diaminopyrazole will preferably be used and more preferentially still 4,5-diamino-l -(P-hydroxycthyl)pyrazolc and/or a corresponding salt.

The pyrazole derivatives which may also be mentioned comprise diamino- N,N-dihydropyrazolopyrazolones and in particular those described in Patent Application FR-A-2 886 136, such as the following compounds and the corresponding addition salts: 2,3-diamino-6,7-dihydro-lH,5H-pyrazolo[l,2-a]pyrazol-l-one, 2- amino-3-ethylamino-6,7-dihydro-lH,5H-pyrazolo[l,2-a]pyrazol- l-one, 2-amino-3- isopropylamino-6, 7-dihydro- lH,5H-pyrazolo[l,2-a]pyrazol-l-one, 2-amino-3-

(pyrrolidin-l-yl)-6, 7-dihydro- lH,5H-pyrazolo[l,2-a]pyrazol-l-one, 4, 5-diamino- 1,2- dimethyl- 1 ,2-dihydropyrazol-3-one, 4,5-diamino- 1 ,2-diethyl- 1 ,2-dihydropyrazol-3- one, 4, 5-diamino- l,2-bis(2-hydroxyethyl)-l,2-dihydropyrazol-3-one, 2-amino-3-(2- hydroxyethyl)amino-6,7-dihydro-lH,5H-pyrazolo[l,2-a]pyrazol- l-one, 2-amino-3- dimethylamino-6, 7-dihydro- lH,5H-pyrazolo[l,2-a]pyrazol-l-one, 2,3-diamino- 5,6,7,8-tetrahydro-lH,6H-pyridazino[l,2-a]pyrazol-l-one, 4-amino- l,2-diethyl-5- (pyrrolidin-l-yl)-l,2-dihydropyrazol-3-one, 4-amino-5-(3-dimethylaminopyrrolidin- 1-yl)- 1, 2-diethyl- l,2-dihydropyrazol-3-one and 2,3-diamino-6-hydroxy-6,7-dihydro- 1 H,5H-pyrazolo [ 1 ,2- a]pyrazol- 1 -one.

Use will preferably be made of 2, 3-diamino-6, 7-dihydro- 1H,5H- pyrazolo[l,2-a]pyrazol-l-one and/or a corresponding salt.

Use will preferably be made, as heterocyclic bases, of 4,5-diamino- 1-(b- hydroxyethyl)pyrazole and/or 2, 3-diamino-6, 7-dihydro- lH,5H-pyrazolo[l, 2- a]pyrazol-l-one and/or 2^-hydroxyethoxy-3-aminopyrazolo[l,5-a]pyridine and/or a corresponding salt.

According to a preferred embodiment of the invention, the oxidation base(s) are chosen from para-phenylenediamine, para-toluenediamine, para-aminophenol, N,N-bis(b-hydroxyethyl)-para-phenylenediamine, 4,5-diamino- 1-(b- hydroxyethyl)pyrazole, 2, 3-diamino-6, 7-dihydro- lH,5H-pyrazolo[l,2-a]pyrazol-l- one, 2^-hydroxyethoxy-3-aminopyrazolo[l,5-a]pyridine, and their addition salts.

Preferably, when the oxidation dye precursor(s) is (are) contained in one or more solid particles as defined above and is an (are) oxidation base(s), the oxidation base(s) advantageously represent from 0.1% to 50% by weight, more preferentially from 0.3% to 25% by weight, more preferentially still from 0.4% to 22% by weight, with respect to the total weight of the solid particle containing it (them).

By way of example, the oxidation couplers can be chosen from meta- phenylenediamines, meta-aminophenols, meta-diphenols, naphthalene -based coupling agents and heterocyclic coupling agents, and also their geometrical or optical isomers, their tautomers, their corresponding addition salts or their solvates according to the invention.

Mention may be made, for example, of 1,3-dihydroxybenzene, 1,3- dihydroxy-2-methylbenzene, 4-chloro- 1,3-dihydroxybenzene, 2,4-diamino- 1 -(b- hydroxyethyloxy)benzene, 2-amino-4-(P-hydroxycthylamino)-l -mcthoxy benzene,

1.3-diaminobenzene, l,3-bis(2,4-diaminophenoxy)propane, 3-ureidoaniline, 3-ureido-

1-dimethylaminobenzene, sesamol, 1 - b - h y dro x y ct h y 1 a m i no- 3 ,4- methylenedioxybenzene, a-naphthol, 2-methyl- 1-naphthol, 6-hydroxyindole, 4- hydroxyindole, 4-hydroxy-N-methylindole, 2-amino-3-hydroxypyridine, 6- hydroxybenzomorpholine, 3,5-diamino-2,6-dimethoxypyridine, 1-N-(b- hydroxyethyl)amino-3,4-methylenedioxybenzene, 2,6-bis^- hydroxyethylamino)toluene, 6-hydroxyindoline, 2,6-dihydroxy-4-methylpyridine, 1- H-3-methylpyrazol-5-one, l-phenyl-3-methylpyrazol-5-one, 2,6- dimethylpyrazolo[l,5-b][l,2,4]triazole, 2,6-dimethyl[3,2-c][l,2,4]triazole and 6- methylpyrazolo[l,5-a]benzimidazole, 2-methyl-5-aminophenol, 5-N-(b- hydroxyethyl)amino-2-methylphenol, 3-aminophenol, 3-amino-2-chloro-6- methylphenol, 2-([3-amino-4-methoxyphenyl]amino)ethanol, and the corresponding addition salts with an acid.

According to a preferred embodiment of the invention, the oxidation coupler(s) are chosen from meta-phenylenediamines, meta-aminophenols, meta diphenols, naphthalene -based coupling agents, heterocyclic coupling agents, and their corresponding addition salts or their solvates, more preferentially still 1,3- dihydroxybenzene, l,3-dihydroxy-2-methylbenzene, 3-aminophenol, 6- hydroxybenzomorpholine, 5-N-(B-hydroxyethyl)amino-2-methylphenol, 2,4-diamino- l-(B-hydroxyethyloxy)benzene, 2-methyl-5-aminophenol, 6-hydroxyindole, 4-chloro-

1.3-dihydroxybenzene, 2-amino-3-hydroxypyridine, 3-amino-2-chloro-6- methylphenol, a-naphthol, 2-([3-amino-4-methoxyphenyl]amino)ethanol and their addition salts. Preferably, when the oxidation dye precursor(s) is (are) contained in one or more solid particles as defined above and is an (are) oxidation coupler(s), the oxidation coupler(s) advantageously represent(s) from 0.1% to 50% by weight, more preferentially from 0.3% to 25% by weight, more preferentially still from 0.4% to 22% by weight, with respect to the total weight of the solid particle containing it (them).

Preferably, the total content of oxidation dye precursor(s) present in each solid particle is between 0.1% and 50% by weight, more preferentially between 0.3% and 25% by weight, more preferentially still between 0.4% and 22% by weight, with respect to the total weight of each solid particle containing it (them).

Preferably, the total content of oxidation dye precursor(s) present in the composition M advantageously represents from 0.0001% to 15% by weight, more preferentially from 0.001% to 10% by weight, more preferentially still from 0.005% to 5% by weight, with respect to the total weight of the composition M.

According to a preferred embodiment, when the oxidation dye precursor(s) are contained in one or more identical or different solid particles as defined above, the content of oxidation dye precursor(s) (for example Cl, C2, and more generally Cl to Cn) advantageously represents from 0.1% to 50% by weight, more preferentially from 0.3% to 25% by weight, more preferentially still from 0.4% to 22% by weight, with respect to the total weight of each solid particle containing it (them) (for example, the solid particles of PI, P2 type, and more generally PI to Pn type respectively).

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

The direct dyes

When the treatment method according to the invention is a method for dyeing keratin fibres, the step of preparation of the composition M can optionally comprise the mixing with one or more direct dyes.

According to a preferred embodiment of the invention, and in the same way as for the oxidation dye precursors above, the direct dye(s) is (are) introduced in the form of solid particles, which are identical or different, each containing one or more direct dye(s).

According to this embodiment, said direct dye(s) can be identical or different from one solid particle to the other.

In particular, the direct dye(s) can be chosen from cationic, anionic and non ionic direct dyes and their mixtures, more particularly from cationic and non-ionic direct dyes and their mixtures.

The direct dyes can be synthetic or natural.

Examples of suitable direct dyes which may be mentioned comprise azo direct dyes; (poly)methine dyes, such as cyanines, hemicyanines and styryls; carbonyl dyes; azine dyes; nitro(hetero)aryl dyes; tri(hetero)arylmethane dyes; porphyrin dyes; phthalocyanine dyes and natural direct dyes, alone or in the form of mixtures.

Mention may be made of the dyes described in Patent Applications WO 95/15144, WO 95/01772 and EP 714954.

In particular, the useful direct dyes can be chosen from Basic Red 51, Basic Yellow 87 and Basic Orange 31 or corresponding derivatives:

Basic Red 51 Basic Orange 31 Basic Yellow 87

Mention may be made, among the natural direct dyes which can be used, of hennotannic acid, juglone, alizarin, purpurin, carminic acid, kermesic acid, purpurogallin, protocatechualdehyde, indigo, isatin, curcumin, spinulosin, apigenidin and orcein. Extracts or decoctions containing these natural dyes and in particular henna-based extracts or poultices can also be used.

Preferably, when the direct dye(s) are present in said solid particles, the direct dye(s) advantageously represent(s) from 0.001% to 10% by weight, more preferentially from 0.005% to 5% by weight, with respect to the total weight of each solid particle containing it (them).

More preferentially, when the direct dye(s) are present in the step of preparation of the composition M, the total content of direct dye(s) present in the composition M advantageously represents from 0.0001% to 15% by weight, more preferentially from 0.001% to 10% by weight, more preferentially still from 0.005% to 5% by weight, with respect to the total weight of the composition M.

According to another preferred embodiment of the invention, when the treatment method according to the invention is a method for dyeing keratin fibres, the step of preparation of the composition M comprises the mixing with one or more direct dyes and with one or more oxidation dye precursors; more preferentially, the direct dye(s) and the oxidation dye precursor(s) are in the form of solid particles as described above.

The binding agents

When the oxidation dye precursor(s) and/or the direct dye(s) are contained in one or more solid particles, which are identical or different, as defined above, the solid particles (for example, the solid particles of PI and P2 type and more generally PI to Pn type) preferably comprise, in addition, at least one binding agent. The term "binding agent" is understood to mean, within the meaning of the invention, a compound contributing to the cohesion of the solid particle. The binding agent makes possible in particular the agglomeration of the different components constituting the solid particle.

Mention may in particular be made, as examples of binding agents, of proteins (such as gelatin); saccharides and their derivatives, oligosaccharides and their derivatives, including disaccharides (such as sucrose and lactose), in particular in their anhydrous or hydrated forms, and sugar alcohols (such as xylitol, sorbitol and maltitol); polyvinyl alcohol (PVA); polysaccharides and their derivatives (for example, starches, cellulose and/or modified cellulose); alginate; and gums (for example, acacia gum, guar gum).

Examples of appropriate modified cellulose comprise microcrystalline cellulose (MCC), in particular in their anhydrous or hydrated forms, and cellulose ethers, such as hydroxypropyl cellulose (HPC) and hydroxypropylmethyl cellulose (HPMC).

Preferably, the binding agent(s) are chosen from saccharides and their derivatives, oligosaccharides and their derivatives, polysaccharides and their derivatives, polyvinyl alcohol (PVA), and their mixtures; more preferentially from lactose, in particular in the anhydrous or hydrated form, microcrystalline cellulose (MCC), in particular in the anhydrous or hydrated form, polyvinyl alcohol (PVA), cellulose ethers, such as hydroxypropyl cellulose (HPC) and hydroxypropylmethyl cellulose (HPMC), and their mixtures.

Preferably, when the binding agent(s) are present in the solid particles, the total content of binding agent(s) is greater than or equal to 30% by weight; more preferentially greater than or equal to 50% by weight; more preferentially still between 50% and 99.9% by weight, better still between 60% and 99.9% by weight, even better still between 70% and 99.9% by weight, with respect to the total weight of each solid particle containing it (them).

The disintegrating agents

When the oxidation dye precursor(s) and/or the direct dye(s) are contained in one or more solid particles, which are identical or different, as defined above, the solid particles (for example, the solid particles of PI and P2 type and more generally PI to Pn type) preferably comprise, in addition, at least one disintegrating agent.

Within the meaning of the present invention, the term "disintegrating agents" is understood to mean a category of agents, preferably a category of polymers, which are particularly effective in bringing about the disintegration of a solid particle (for example a tablet). A specific category of disintegrating agents is known as "super- disintegrating agents" as they are generally effective at low concentrations.

The disintegrating agents can be hygroscopic compounds which act by absorbing the liquid of a medium when they are brought into contact with this medium (for example the water of an aqueous medium). Such an absorption can then bring about a disintegration by causing a considerable swelling of the disintegrating agent and/or by reinforcing the capillary action. The swelling pressure exerted by a disintegrating agent swollen in an external or radial direction can bring about the bursting of a solid particle (for example a tablet).

Mention may in particular be made, as examples of disintegrating agents, indeed even of super disintegrating agents, of crosslinked celluloses, such as croscarmellose (or crosslinked carboxymethylcellulose, which is generally used in the sodium salt form) and its derivatives, sold, for example, under the references Ac-Di- Sol ^® , Explocel ^® , Nymcel ZSX ^® , Pharmacel ^® XL, Primellose ^® , Solutab ^® and Vivasol ^® ; crospovidone (or crosslinked polyvinylpyrrolidone) and its derivatives, sold, for example, under the references Crospovidone M ^® , Kollidon ^® and Polyplasdone ^® ; crosslinked starch, such as sodium starch glycolate, sold, for example, under the references Explotab ^® , Explotab ^® CLV, Explosol ^® , Primojel ^® , Tablo ^® and Vivastar ^® ; crosslinked alginic acids, sold, for example, under the reference Satialgine ^® ; crosslinked polyacrylic compounds, such as ion-exchange resins, sold, for example, under the references Indion ^® 414, Tulsion ^® 339 and Amberlite ^® IRP; and certain polysaccharides, such as soybean polysaccharide, sold, for example, under the references Emcosoy ^® superdisintegrant.

Preferably, the disintegrating agent(s) are polymeric; more preferentially, each type of solid particle comprises at least one disintegrating polymer, better still at least one super-disintegrating polymer; more preferentially still at least one super- disintegrating polymer chosen from crosslinked polymers of vinylpyrrolidone and its derivatives, and their mixtures; even better still from crosslinked polyvinylpyrrolidones, crosslinked vinylpyrrolidone/vinyl acetate copolymers, and their mixtures.

Preferably, when the disintegrating agent(s) are present in the solid particles, the total content of disintegrating agent(s) is between 0.5% and 15% by weight, more preferentially between 1% and 12% by weight, more preferentially still between 2% and 10% by weight, with respect to the total weight of each solid particle containing it (them).

The antioxidants

When the oxidation dye precursor(s) and/or the direct dye(s) are contained in one or more solid particles, which are identical or different, as defined above, the solid particles (for example, the solid particles of PI and P2 type and more generally PI to Pn type) preferably comprise, in addition, at least one antioxidant.

Mention may in particular be made, as examples of antioxidant(s), of ascorbic acid, its salts and its derivatives (such as sodium ascorbate, erythorbic acid, ascorbyl palmitate, ascorbyl laurate); salicylic acid, its salts and its derivatives (such as sodium salicylate); mercaptans and inorganic sulfites (such as sodium sulfite, sodium bisulfite, sodium metabisulfite, potassium sulfite and thioglycolic acid); 2,6-di(tert-butyl)-4- methylphenol (BHT); butylated hydroxyanisole (BHA); sodium dithionite; and their mixtures.

Preferably, the antioxidant(s) are chosen from ascorbic acid, its salts and its derivatives (such as sodium ascorbate, erythorbic acid, ascorbyl palmitate, ascorbyl laurate); salicylic acid, its salts and its derivatives (such as sodium salicylate); mercaptans and inorganic sulfites (such as sodium sulfite, sodium bisulfite, sodium metabisulfite, potassium sulfite and thioglycolic acid), and their mixtures; more preferentially from ascorbic acid, sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium salicylate, and their mixtures.

Preferably, when the antioxidant(s) are present in the solid particles, the total content of antioxidant(s) is between 0.1% and 15% by weight, more preferentially between 0.3% and 12% by weight, more preferentially still between 0.4% and 10% by weight, better still between 0.5% and 5% by weight, with respect to the total weight of each solid particle containing it (them).

Lubricating and/or anti-adhesion agents

When the oxidation dye precursor(s) and/or the direct dye(s) are contained in one or more solid particles, which are identical or different, as defined above, the solid particles (for example, the solid particles of PI and P2 type and more generally PI to Pn type) preferably comprise, in addition, at least one lubricating and/or anti-adhesion agent.

Within the meaning of the invention, the term "lubricating and/or anti adhesion agent" is understood to mean a compound which makes it possible to reduce, indeed even to prevent, the agglomeration of the ingredients of the solid particles, to reduce the adhesion (in particular during a compression step) and/or to improve the flow of the ingredients of the solid particles by reducing the friction and the cohesion between the ingredients.

Preferably, the lubricating and/or anti-adhesion agent(s) are chosen from magnesium stearate, calcium silicate, magnesium silicate, magnesium carbonate, silicon dioxide, talc, silica, stearic acid, sodium stearoyl fumarate, and their mixtures; more preferentially from silica, magnesium stearate, and their mixtures.

Preferably, when the lubricating and/or anti-adhesion agent(s) are present in the solid particles, the total content of lubricating and/or anti-adhesion agent(s) is between 0.1% and 10% by weight, more preferentially between 0.3% and 8% by weight, more preferentially still between 0.5% and 5% by weight, with respect to the total weight of each solid particle containing it(them).

Upper coating layer

When the oxidation dye precursor(s) and/or the direct dye(s) are contained in one or more solid particles, which are identical or different, as defined above, the solid particles (for example, the solid particles of PI and P2 type and more generally PI to Pn type) preferably comprise, in addition, an upper coating layer (also known as upper film-coating layer). The upper coating layer can optionally comprise cellulose ethers, such as those described above.

The upper coating layer can optionally comprise one or more other compounds, such as polyethylene glycol (PEG); polyvinyl alcohol (PVA); polyvinylpyrrolidone (PVP); their copolymers (for example, a polyvinyl alcohol/polyethylene glycol PV A/PEG copolymer); sugars, such as xanthan; and their mixtures.

Preferably, the upper coating layer comprises at least two different cellulose ethers.

According to a preferred embodiment of the invention, the upper coating layer comprises at least one cellulose ether as described above; more preferentially a cellulose ether chosen from carboxymethylcellulose (CMC), ethylcellulose (EC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), methylhydroxy ethylcellulose (MHEC), and their mixtures, better still from hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), and their mixtures.

More preferentially, the upper coating layer comprises hydroxypropylcellulose (HPC) and hydroxypropylmethylcellulose (HPMC).

Preferably, according to this embodiment of the invention, the content of cellulose ether(s) present in the upper coating layer is between 30% and 99% by weight, more preferentially between 40% and 90% by weight, more preferentially still between 50% and 70% by weight, with respect to the total weight of the upper coating layer.

According to another preferred embodiment according to the invention, the upper coating layer comprises at least one lubricating and/or anti-adhesion agent as described above; more preferentially at least one lubricating and/or anti-adhesion agent chosen from calcium silicate, magnesium silicate, magnesium carbonate, silicon dioxide, talc, silica, and their mixtures; more preferentially, the lubricating and/or anti adhesion agent is talc.

Preferably, according to this embodiment, the total content of lubricating and/or anti-adhesion agent(s) present in the upper coating layer is between 1% and 40% by weight, more preferentially between 2% and 30% by weight, with respect to the total weight of the upper coating layer. Preferably, the upper coating layer additionally comprises one or more pigments.

By way of examples, the pigments can be white or coloured, inorganic and/or organic, and coated or non-coated. Mention may be made, among inorganic pigments, of metal oxides, in particular titanium dioxide, optionally surface-treated, zirconium, zinc or cerium oxides, and also iron, titanium or chromium oxides, manganese violet, ultramarine blue, ultramarine pink, chromium hydrate and ferric blue, and their mixtures. Mention may be made, among organic pigments, of carbon black, pigments of D & C type, and lacquers based on cochineal carmine of barium, strontium, calcium or aluminium, and their mixtures.

According to a preferred embodiment of the invention, the upper coating layer additionally comprises one or more pigments chosen from zirconium oxides, zinc oxides, cerium oxides, iron oxides, titanium oxides, chromium oxides, manganese violet, ultramarine blue, ultramarine pink, chromium hydrate and ferric blue, and their mixtures; more preferentially, one or more pigments chosen from titanium oxides, such as titanium dioxide, iron oxides, chromium oxides, in particular green chromium oxide, and their mixtures.

When the upper coating layer comprises one or more pigments, the pigment(s) advantageously represent a total content ranging from 1% to 50% by weight, more preferentially from 5% to 40% by weight, with respect to the total weight of the upper coating layer.

Preferably, said solid particles as described above are anhydrous.

The term "anhydrous solid particle" is understood to mean that the solid particle contains less than 2% by weight of water, preferably less than 1% by weight of water, and more preferentially still less than 0.5% by weight of water, with respect to the total weight of the solid particle, and indeed even said solid particle is devoid of water. In particular, the water possibly present is not added during the preparation of the solid particle but corresponds to the residual water introduced by the ingredients mixed. Said solid particles as described above can advantageously be provided in a spherical or spheroidal form; more preferentially in a spherical form, such as in a bead form.

Preferably, said solid particles exhibit a mean volume between 25 and 125 mm ³ ; more preferentially between 30 and 90 mm ³ ; more preferentially still between 45 and 65 mm ³ .

The volume V of a solid particle in a substantially spherical or spheroidal form can in particular be calculated by the following equation:

V = (4/3). p.G ³ in which r represents the radius of the solid particle.

Preferably, said solid particles exhibit a mean weight between 30 and 120 mg; more preferentially between 40 and 80 mg; more preferentially between 50 and 70 mg.

Preferably, the mean hardness of said solid particles is between 2 and 15 kPa; more preferentially between 2 and 11 kPa.

The mean hardness of said solid particles can, for example, be measured using a semiautomatic system for the testing of tablets commonly used in the pharmaceutical field, in particular using the Pharmatron ST50 device.

Preferably, the solid particles according to the invention exhibit a mean disintegration time, in 25 ml of aqueous hydrogen peroxide solution (comprising 6% by weight of H2O2) at 25°C and at atmospheric pressure, of less than 60 seconds, more preferentially less than 40 seconds, better still between 1 and 30 seconds.

By way of example, the mean disintegration time can be measured according to the following method:

1) 25 ml of an aqueous oxidizing composition comprising 6% by weight of hydrogen peroxide are poured into a 50 ml beaker; then

2) in a single go, 10 identical colouring solid particles according to the invention are added; the contents of the beaker are not mixed; then

3) the stopwatch is started;

4) the stopwatch is stopped, once all the solid particles have clearly visually broken up; that is to say, once it is observed that the solid particles form a soft mass no longer containing a firm core; and finally

5) the mean disintegration time on the stopwatch is recorded. Said solid particles are advantageously prepared according to conventional processes for the preparation of tablets, which are optionally film-coated, such as the processes used in the pharmaceutical industry.

More particularly, the solid particles according to the invention can be prepared by the dry route according to the following steps: milling the ingredients of the solid particle; then sieving the powder obtained; then mixing said powder; then direct compression of the mixture obtained to give a solid particle; and optionally coating the solid particles obtained.

According to another specific embodiment, the solid particles according to the invention can be prepared by wet granulation according to the following steps: premixing the binding agent(s) (for example lactose, microcrystalline cellulose, polyvinyl alcohol (PVA)) and the dye(s); then spraying, over the premix, the disintegrating agent(s) (for example a crosslinked polyvinylpyrrolidone) in solution in one or more solvents, such as those described in the section below for the coating composition, in particular in water, in order to obtain the desired aggregate; then drying the aggregate; then milling the other ingredients of the solid particle; then sieving the powder obtained by the milling and the aggregate; then mixing the powders obtained by the sieving; then direct compression of the mixture obtained to give a solid particle; and optionally coating the solid particles obtained.

The coating composition, which makes possible the coating of the solid particles, comprises one or more cellulose ethers as described above for the upper coating layer. Preferably, said coating composition additionally comprises one or more of the preferred ingredients of the upper coating layer as described above; more preferentially contents thereof as described above in the upper coating layer.

More preferentially, said coating composition additionally comprises one or more solvents chosen from water, C1-C6 alcohols, and their mixtures; more preferentially still chosen from water, ethanol, and their mixtures.

By way of example, the coating composition can be prepared from one or more solvents, in particular as described above, and from a mixture containing hydroxypropylmethylcellulose and hydroxypropylcellulose. According to this example, the coating composition can optionally contain one or more fatty substances, which is/are preferably liquid at 25°C and at atmospheric pressure, such as one or more fatty alcohols, fatty esters and/or triglycerides, for example chosen from octyldodecanol, isopropyl myristate, a vegetable oil and/or caprylic/capric acid triglyceride.

The composition can also optionally contain talc and/or pigments in order to colour the coating, preferably talc and pigments, such as titanium dioxide.

The milling step can in particular be carried out using a mill, for example of Quadro ^® Comil ^® U5 type.

The sieving step can in particular be carried out using a granulator, for example of Roto P50 (Zanchetta) or High Shear Mixer P/VAC- 10 (Diosna) type.

The mixing step can in particular be carried out using a mixer, for example of MB015 Blender (Pharmatech) type.

The step of direct compression of the mixture can in particular be carried out using a compression plate, for example of PR-1500 (PTK) type.

The step of coating said particles can in particular be carried out using a film coating station, for example of LDCS-Pilot Hi-Coater ^® (Freund- Vector) type.

Composition A:

The treatment method according to the present invention employs at least one composition A comprising arginine.

Preferably, the total content of arginine present in the composition A is between 0.05% and 25% by weight, more preferentially between 0.1% and 15% by weight, more preferentially still between 0.5% and 10% by weight, indeed even between 1% and 5% by weight, with respect to the total weight of the composition A.

Preferably, the water content of the composition A according to the invention is between 30% and 99% by weight, more preferentially between 40% and 90% by weight, even better still between 50% and 80% by weight, with respect to the total weight of the composition A.

The additional alkaline agents

The composition A according to the invention preferably comprises, moreover, at least one additional alkaline agent other than arginine.

Preferably, the additional alkaline agent(s) can be chosen from organic alkaline agents and inorganic alkaline agents.

Preferably, the organic additional alkaline agent(s) are chosen from organic amines, the pK _b of which at 25°C is less than 12, more preferentially less than 10 and more advantageously still less than 6. It should be noted that it is the pK _b corresponding to the functional group of highest basicity. In addition, the organic amines do not comprise an alkyl or alkenyl fatty chain comprising more than ten carbon atoms.

The organic additional alkaline agent(s) are preferably chosen from alkanolamines, such as mono-, di- or trialkanolamines, comprising from one to three identical or different Ci to CA hydroxy alkyl radicals.

The term "alkanolamine" is understood to mean an organic amine comprising a primary, secondary or tertiary amine functional group, and one or more linear or branched Ci to Cs alkyl groups carrying one or more hydroxyl radicals.

The alkanolamines chosen from monoethanolamine (MEA), diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, N,N- dimethylethanolamine, 2-amino-2-methyl-l -propanol, triisopropanolamine, 2-amino- 2-methyl- 1 ,3 -propanediol, 3-amino- 1 ,2-propanediol, 3-dimethylamino- 1 ,2- propanediol or tris(hydroxymethyl)aminomethane are suitable in particular for the implementation of the invention. Among the alkanolamines, it is very particularly preferred to use monoethanolamine.

The amino acids other than arginine which can be used are of natural or synthetic origin, in their L, D or racemic form, and comprise at least one acid functional group chosen more particularly from carboxylic acid, sulfonic acid, phosphonic acid or phosphoric acid functional groups. The amino acids can be in neutral or ionic form. Mention may in particular be made, as amino acids other than arginine which can be used in the present invention, of aspartic acid, glutamic acid, alanine, ornithine, citrulline, asparagine, carnitine, cysteine, glutamine, glycine, histidine, lysine, isoleucine, leucine, methionine, N-phenylalanine, proline, serine, taurine, threonine, tryptophan, tyrosine and valine.

Advantageously, the amino acids other than arginine are basic amino acids comprising an additional amine functional group optionally included in a ring or in a ureido functional group.

The organic amine can also be chosen from organic amines of heterocyclic type. Mention may in particular be made, besides histidine, already mentioned in the amino acids, of pyridine, piperidine, imidazole, triazole, tetrazole or benzimidazole.

The organic amine can also be chosen from amino acid dipeptides. Mention may in particular be made, as amino acid dipeptides which can be used in the present invention, of carnosine, anserine and balenine.

The organic amine can also be chosen from compounds comprising a guanidine functional group. Mention may in particular be made, as amines of this type which can be used in the present invention, in addition, of creatine, creatinine, 1,1- dimethylguanidine, 1,1-diethylguanidine, glycocy amine, metformin, agmatine, N- amidinoalanine, 3-guanidinopropionic acid, 4-guanidinobutyric acid and 2- ([amino(imino)methyl]amino)ethane- 1 -sulfonic acid.

Mention may be made, among the inorganic additional alkaline agents which can be used in the method according to the invention, of inorganic hydroxides.

The inorganic hydroxides can be chosen from alkali metal, alkaline earth metal, transition metal or ammonium hydroxides. Mention may be made, as inorganic hydroxides, for example, of ammonium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, barium hydroxide, strontium hydroxide, manganese hydroxide or zinc hydroxide.

Among inorganic hydroxides, ammonium hydroxide, also known as aqueous ammonia, is preferred.

The inorganic additional alkaline agent(s) can also be chosen from urea, ammonium salts, such as ammonium chloride, ammonium sulfate, ammonium phosphate or ammonium nitrate, or silicates, phosphates or carbonates of alkali metals or alkaline earth metals, such as lithium, sodium, potassium, magnesium, calcium or barium, and their mixtures, preferably from silicates of alkali metals or alkaline earth metals, in particular metasilicates of alkali metals or alkaline earth metals, such as sodium metasilicate.

Preferably, the additional alkaline agent(s) other than arginine of use in the invention are chosen from aqueous ammonia, metasilicates of alkali metals or alkaline earth metals, alkanolamines, amino acids in the neutral or ionic form, in particular basic amino acids, compounds comprising a guanidine functional group, and preferably from aqueous ammonia, metasilicates of alkali metals or alkaline earth metals and alkanolamines.

According to a preferred embodiment of the invention, the composition A comprises one or more additional alkaline agents other than arginine, more preferentially chosen from aqueous ammonia, alkanolamines, metasilicates of alkali metals or alkaline earth metals, and their mixtures, more preferentially still from aqueous ammonia, monoethanolamine, sodium metasilicate, and their mixtures.

Preferably, when the additional alkaline agent(s) other than arginine are present in the composition A, the total content of additional alkaline agent(s) other than arginine is between 0.05% and 25% by weight, more preferentially between 0.1% and 20% by weight and more preferentially still between 0.5% and 15% by weight, with respect to the total weight of the composition A.

Advantageously, the pH of the aqueous composition A according to the invention generally varies from 8 to 13, preferably from 9 to 12.5, better still from 10 to 12.5.

Oxidizing composition B:

The treatment method according to the present invention employs at least one oxidizing composition B separate from the composition A comprising one or more chemical oxidizing agents and one or more acrylic anionic associative polymers.

Preferably, the water content of the oxidizing composition B according to the invention is between 30% and 99% by weight, more preferentially between 50% and 99% by weight, even better still between 60% and 90% by weight, with respect to the total weight of the aqueous composition B. Chemical oxidizing agents

The oxidizing composition B according to the invention comprises one or more chemical oxidizing agents.

Within the meaning of the present invention, the term "chemical oxidizing agent" is understood to mean an oxidizing agent other than atmospheric oxygen.

The chemical oxidizing agent(s) (or bleaching agents) which can be used in the present invention can be chosen from hydrogen peroxide, urea hydrogen peroxide, alkali metal bromates, persalts, such as perborates and persulfates, in particular sodium persulfate, potassium persulfate and ammonium persulfate, peracids and oxidase enzymes (with their optional cofactors), among which may be mentioned peroxidases, 2-electron oxidoreductases, such as uricases, and 4-electron oxygenases, such as laccases, and their mixtures; more preferentially, the chemical oxidizing agent(s) are chosen from hydrogen peroxide, persalts, and their mixtures.

Preferably, the total content of chemical oxidizing agent(s) present in the oxidizing composition B is between 0.1% and 35% by weight, more preferentially between 0.1% and 30% by weight and more preferentially still between 0.5% and 25% by weight, better still from 2% to 12% by weight, with respect to the total weight of the oxidizing composition B.

The acrylic anionic associative polymers

The oxidizing composition B according to the invention comprises one or more acrylic anionic associative polymers.

It is recalled that "associative polymers" are polymers which are capable, in an aqueous medium, of reversibly associating with one another or with other molecules.

Their chemical structure more particularly comprises at least one hydrophilic region and at least one hydrophobic region.

The term "hydrophobic region" is understood to mean a radical or polymer having a saturated or unsaturated and linear or branched hydrocarbon chain comprising at least 8 carbon atoms, preferably from 10 to 30 carbon atoms, in particular from 12 to 30 carbon atoms and more preferentially from 18 to 30 carbon atoms.

Preferentially, the hydrocarbon group originates from a monofunctional compound. By way of example, the hydrophobic group can result from a fatty alcohol, such as, for example, stearyl alcohol, dodecyl alcohol or decyl alcohol. It can also denote a hydrocarbon polymer, such as, for example, polybutadiene.

The term "fatty alcohol", within the meaning of the invention, is understood to mean a compound of formula R-OH with R denoting a saturated or unsaturated and linear or branched hydrocarbon chain which is optionally substituted and which comprises at least 8 carbon atoms, preferably from 10 to 30 carbon atoms, in particular from 12 to 30 carbon atoms and more preferentially from 18 to 30 carbon atoms.

The term "fatty acid", within the meaning of the invention, is understood to mean a compound of formula R-COOH with R denoting a saturated or unsaturated and linear or branched hydrocarbon chain which is optionally substituted and which comprises at least 8 carbon atoms, preferably from 10 to 30 carbon atoms, in particular from 12 to 30 carbon atoms and more preferentially from 18 to 30 carbon atoms.

Mention may be made, among acrylic anionic associative polymers, of:

- (a) those comprising at least one hydrophilic unit and at least one fatty-chain allyl ether unit, more particularly those for which the hydrophilic unit is constituted by an ethylenic unsaturated anionic monomer, more particularly still by a vinylcarboxylic acid and very particularly by an acrylic acid or a methacrylic acid or the mixtures of these.

Among these acrylic anionic associative polymers, preference is very particularly given, according to the invention, to polymers formed from 20% to 60% by weight of acrylic acid and/or of methacrylic acid, from 5% to 60% by weight of lower alkyl (meth)acrylates, from 2% to 50% by weight of fatty-chain allyl ether and from 0% to 1% by weight of a crosslinking agent which is a well-known copolymerizable unsaturated polyethylenic monomer, such as diallyl phthalate, allyl (meth)acrylate, divinylbenzene, (poly)ethylene glycol dimethacrylate and methylenebisacrylamide.

Among the latter polymers, preference is very particularly given to crosslinked terpolymers of methacrylic acid, of ethyl acrylate and of polyethylene glycol (10 OE) ether of stearyl alcohol (Steareth 10), in particular those sold by CIBA under the names Salcare SC80® and Salcare SC90®, which are 30% aqueous emulsions of a crosslinked terpolymer of methacrylic acid, of ethyl acrylate and of steareth-10 allyl ether (40/50/10). - (b) those comprising i) at least one hydrophilic unit of unsaturated olefinic carboxylic acid type, and ii) at least one hydrophobic unit of C10-C30 alkyl ester of unsaturated carboxylic acid type.

C10-C30 alkyl esters of unsaturated carboxylic acids which are useful in the invention comprise, for example, lauryl acrylate, stearyl acrylate, decyl acrylate, isodecyl acrylate and dodecyl acrylate, and the corresponding methacrylates, lauryl methacrylate, stearyl methacrylate, decyl methacrylate, isodecyl methacrylate and dodecyl methacrylate.

Anionic associative polymers of this type are, for example, described and prepared according to Patents US 3 915 921 and US 4 509 949.

Use will more particularly be made, among anionic associative polymers of this type, of those constituted of 95% to 60% by weight of acrylic acid (hydrophilic unit), 4% to 40% by weight of C10-C30 alkyl acrylate (hydrophobic unit) and 0% to 6% by weight of crosslinking polymerizable monomer, or else those constituted of 98% to 96% by weight of acrylic acid (hydrophilic unit), 1% to 4% by weight of C10-C30 alkyl acrylate (hydrophobic unit) and 0.1% to 0.6% by weight of crosslinking polymerizable monomer, such as those described above.

Among said polymers above, preference is very particularly given, according to the present invention, to the products sold by Goodrich under the trade names Pemulen TR1®, Pemulen TR2® and Carbopol 1382®, and more preferentially still Pemulen TR1®, and the product sold by SEPPIC under the name Coatex SX®.

Mention may also be made of the acrylic acid/lauryl methacrylate/vinylpyrrolidone terpolymer sold under the name Acrylidone LM by ISP.

- (c) acrylic terpolymers comprising: i) approximately 20% to 70% by weight of an a,b- monoethylenically unsaturated carboxylic acid [A], ii) approximately 20% to 80% by weight of an a,b- monoethylenically unsaturated non-surface-active monomer other than [A], iii) approximately 0.5% to 60% by weight of a non-ionic monourethane which is the reaction product of a monohydric surfactant with a monoethylenically unsaturated monoisocyanate, such as those described in Patent Application EP A 0 173 109 and more particularly that described in Example 3, namely a methacrylic acid/methyl acrylate/dimethyl(meta-isopropenyl)benzyl isocyanate of ethoxylated (40 OE) behenyl alcohol terpolymer, as a 25% aqueous dispersion.

- (d) copolymers comprising, among their monomers, an a,b- monoethylenically unsaturated carboxylic acid and an ester of an a,b- monoethylenically unsaturated carboxylic acid and of an oxyalkylenated fatty alcohol.

Preferentially, these compounds also comprise, as monomer, an ester of an a,b-monoethylenically unsaturated carboxylic acid and of a C1-C4 alcohol.

Mention may be made, as examples of this type of compound, of Aculyn 22® (INCI name: Acrylates/Steareth-20 Methacrylate Copolymer), sold by Rohm and Haas, which is a methacrylic acid/ethyl acrylate/oxyalkylenated stearyl methacrylate terpolymer, and also of Aculyn 88 (INCI name: Acrylates/Steareth-20 Methacrylate Crosspolymer) or Aculyn 28 (INCI name: Acrylates/Beheneth-25 Methacrylate Copolymer), which are also sold by Rohm and Haas.

- (e) their mixtures.

Preferably, the acrylic anionic associative polymer(s) are chosen from polymers not comprising sugar units.

According to a preferred embodiment of the invention, the acrylic anionic associative polymer(s) are chosen from copolymers comprising, among their monomers, an a,b-monoethyleniclly unsaturated carboxylic acid and an ester of an a,b- monoethylenically unsaturated carboxylic acid and of an oxyalkylenated fatty alcohol.

Preferably, the total content of acrylic anionic associative polymer(s) present in the oxidizing composition B is between 0.01% and 10% by weight, more preferentially between 0.05% and 5% by weight and more preferentially still between 0.075% and 3% by weight, better still between 0.1% and 2% by weight, with respect to the total weight of the oxidizing composition B.

Preferably, the composition A and/or the oxidizing composition B used in the method according to the present invention additionally comprise at least one cationic polymer.

Preferably, the cationic polymer(s) can be chosen from: (1) cyclopolymers of alkyldiallylamine or of dialky ldiallylammonium, such as the homopolymers or copolymers comprising, as main constituent of the chain, units corresponding to the formula (I) or (II): in which:

- k and t are equal to 0 or 1, the sum k + t being equal to 1;

- Ri2 denotes a hydrogen atom or a methyl radical;

- Rio and Rn, independently of each other, denote a C1-C6 alkyl group, a Ci- C5 hydroxyalkyl group or a C1-C4 amidoalkyl group; or else Rio and Rn can denote, together with the nitrogen atom to which they are attached, a heterocyclic group, such as piperidinyl or morpholinyl; Rio and Rn, independently of each other, preferably denote a C1-C4 alkyl group;

- Y is an anion, such as bromide, chloride, acetate, borate, citrate, tartrate, bisulfate, bisulfite, sulfate or phosphate.

Mention may more particularly be made of the homopolymer of dimethy ldiallylammonium salts (for example chloride), for example sold under the name Merquat 100 by Nalco, and of the copolymers of dimethyldiallylammonium salts (for example chloride) and of acrylamide' sold in particular under the name Merquat 550 or Merquat 7SPR;

(2) diquatemary ammonium polymers comprising repeat units of the following formula (III): in which: - Ri3, Ri4, Ri5 and Ri ₆ , which are identical or different, represent aliphatic, alicyclic or arylaliphatic radicals comprising from 1 to 20 carbon atoms or C1-C12 hydroxy alkyl aliphatic radicals; or else R13, R14, R15 and Ri ₆ , together or separately, form, with the nitrogen atoms to which they are attached, heterocycles optionally comprising a second heteroatom other than nitrogen; or else R13, R14, R15 and Ri ₆ represent a linear or branched C1-C6 alkyl radical substituted by a nitrile, ester, acyl, amide or -CO-O-Rn-D or -CO-NH-Rn-D group, where Rn is an alkylene and D is a quaternary ammonium group;

- Ai and Bi represent divalent polymethylene groups comprising from 2 to 20 carbon atoms which can be linear or branched and saturated or unsaturated, and which can contain, bonded to or inserted in the main chain, one or more aromatic rings or one or more oxygen or sulfur atoms or sulfoxide, sulfone, disulfide, amino, alkylamino, hydroxyl, quaternary ammonium, ureido, amide or ester groups; and

- X denotes an anion derived from an inorganic or organic acid; it being understood that Ai, R13 and R15 can form, with the two nitrogen atoms to which they are attached, a piperazine ring; in addition, if Ai denotes a saturated or unsaturated and linear or branched alkylene or hydroxyalkylene radical, Bi can also denote a (CH2) _n -CO-D-OC-(CH2) _P - group, with n and p, which are identical or different, being integers varying from 2 to 20, and D denoting: a) a glycol residue of formula -O-Z-O-, where Z denotes a linear or branched hydrocarbon radical or a group corresponding to one of the following formulae: -(CH ₂ CH20)x-CH ₂ CH2- and -[CH ₂ CH(CH3)0] _y -CH ₂ CH(CH3)-, where x and y denote an integer from 1 to 4, representing a defined and unique degree of polymerization, or any number from 1 to 4 representing a mean degree of polymerization; b) a bis-secondary diamine residue, such as a piperazine derivative; c) a bis-primary diamine residue of formula -NH-Y-NH-, where Y denotes a linear or branched hydrocarbon radical, or else the divalent radical -CH2-CH2-S-S- CH2-CH2-; d) a ureylene group of formula -NH-CO-NH-.

Preferably, X is an anion, such as chloride or bromide. These polymers have a number- average molar mass (Mn) generally of between 1000 and 100000. More preferentially, the cationic polymer(s) can be chosen from polyquaternium-6, hexadimethrine chloride, and their mixtures.

The composition A and/or the oxidizing composition B used in the method according to the present invention can optionally additionally comprise one or more additives, such as pearlescent agents; fatty substances; vitamins or provitamins; surfactants, in particular non-ionic surfactants; pH- stabilizing agents; preservatives; fragrances.

A person skilled in the art will take care to choose the optional additives and their amounts so that they do not harm the properties of the methods and compositions of the present invention.

These additives, when they are present, are generally present in the composition A and/or the oxidizing composition B according to the invention in an amount ranging from 0% to 20% by weight, with respect to the total weight of the composition A and/or respectively the oxidizing composition B.

The composition A and/or the oxidizing composition B employed in the method according to the present invention can optionally comprise, in addition, one or more organic solvents.

Mention may be made, as organic solvent, for example, of linear or branched C ₂ to C ₄ alkanols, such as ethanol and isopropanol; glycerol; polyols and polyol ethers, for example 2-butoxyethanol, propylene glycol, hexylene glycol, dipropylene glycol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether and monomethyl ether, and also aromatic alcohols or ethers, such as benzyl alcohol or phenoxy ethanol, and their mixtures.

The method

When the step of preparation of the composition M does not comprise the mixing with one or more oxidation dyes and/or with one or more direct dyes, the method of the invention is a method for bleaching keratin fibres, in particular human keratin fibres, such as the hair.

When the method of the invention is a method for dyeing keratin fibres, in particular human keratin fibres, such as the hair, the step of preparation of the composition M preferably comprises the mixing with one or more oxidation dye precursors. Advantageously, when the oxidation dye precursor(s) and/or the direct dye(s), preferably the oxidation dye precursor(s), are contained in one or more solid particles, which are identical or different, as defined above, step a. of preparation of a composition M according to the invention comprises the mixing of a number N of solid particles, when the latter are identical, or of several numbers N _x , which are identical or different, when the solid particles are different.

N is an integer greater than or equal to 2; and N _x are integers greater than or equal to 1, and x is an index varying from 1 to n with n the number of solid particles of different types.

N and N _x are defined before the use of the composition M, as a function of the hue desired by the user and/or of the specificities of the user, such as the pre-existing hue and/or the nature of the keratin fibres.

Preferably, the numbers N and N _x are defined by means of computer software.

More preferentially, step a. of preparation of a composition M according to the invention comprises the mixing of a number Ni of solid particles(s) of a first type PI as described above with a number N2 of solid particle(s) of a second type P2 as described above, Ni and N2 being integers greater than or equal to 1 defined before the use of the composition M, as a function of the hue desired by the user and/or of the specificities of the user, such as the pre-existing hue and/or the nature of the keratin fibres.

More preferentially still, the numbers Ni and N2 are defined by means of computer software.

Thus, according to a preferred specific embodiment, step a. of preparation of a composition M comprises the mixing of numbers Ni to N _n of solid particle(s) respectively of type PI to Pn (with n representing an integer greater than or equal to 3), the numbers Ni to N _n being integers greater than or equal to 1 defined before the use of the composition M, as a function of the hue desired by the user and/or of the specificities of the user, such as the pre-existing hue and/or the nature of the keratin fibres.

More preferentially according to this embodiment, the numbers Ni to N _n are defined by means of computer software. According to a specific embodiment of the invention, step a. of preparation of a composition M additionally comprises the mixing of said composition A and of said oxidizing composition B with several particles of Px type with one or more solid particles of P'x type (with x representing an integer greater than or equal to 1, and in particular ranging from 1 to n with n as described above, and preferably between 1 and 20, more preferentially between 1 and 15, and more preferentially still between 1 and 10) containing a single dye Cx (i.e., a direct dye Cx or an oxidation dye precursor Cx), better still a single oxidation dye precursor Cx, preferably in a content between 0.1% and 50% by weight, with respect to the total weight of the solid particle(s) of P'x type; said solid particle of P'x type corresponding the solid particle of Px type described above, except for the content of dye Cx, better still of oxidation dye precursor Cx.

By way of example of this specific embodiment of the invention, step a. of preparation of a composition M can comprise the mixing:

(i) of a number Ni of solid particles of a first type PI containing a single dye Cl, better still a single oxidation dye precursor Cl, preferably in a content between 0.1% and 50% by weight, with respect to the total weight of the solid particle(s) of PI type; with

(ii) a number N2 of solid particles of a second type P2 containing a single dye C2, better still a single oxidation dye precursor C2, preferably in a content of between 0.1% and 50% by weight, with respect to the total weight of the solid particle(s) of P2 type;

(iii) a number N'i of solid particles of P'l type containing only said dye Cl, better still said oxidation dye precursor Cl, preferably in a content between 0.1% and 50% by weight, with respect to the total weight of the solid particle(s) of P'l type; and

(iv) at least one composition A comprising arginine;

(v) at least one separate oxidizing composition B comprising one or more chemical oxidizing agents and one or more acrylic anionic associative polymers; it being understood that:

- the dye Cl, better still the oxidation dye precursor Cl, is different from the dye C2, better still the oxidation dye precursor C2; - the content of dye Cl, better still of oxidation dye precursor Cl, contained in the solid particle(s) PI is different from the content of dye Cl, better still of oxidation dye precursor Cl, contained in the solid particle(s) P'l;

- the numbers Ni, N2 and N'i denoting integers greater than or equal to 1, which are identical or different.

Preferably, step a. of preparation of a composition M according to the invention is carried out less than two hours, more preferentially less than one hour, more preferentially still less than 30 minutes, before step b) of application to the keratin fibres of the composition M.

According to a specific embodiment of the invention, step a. of preparation of a composition M comprises the mixing:

(i) of one or more oxidation dye precursors as described above; more preferentially of several solid particles, which are identical or different, each containing one or more oxidation dye precursors as described above; with

(ii) the composition A as described above; and

(iii) the oxidizing composition B separate from the composition A, as described above; and

(iv) one or more additional aqueous compositions other than said compositions A and B.

According to a preferred embodiment of the invention, step a. of preparation of a composition M comprises the mixing:

- of one or more oxidation dye precursors as described above; preferably of several solid particles, which are identical or different, each containing one or more oxidation dye precursors as described above; with

- at least one composition A comprising arginine and optionally one or more additional alkaline agents other than arginine, as described above; and

- at least one separate oxidizing composition B comprising:

(i) at least one chemical oxidizing agent, preferably chosen from those as described above, more preferentially from hydrogen peroxide, persalts and their mixtures, and (ii) one or more acrylic anionic associative polymers as described above, preferably chosen from copolymers comprising, among their monomers, an a,b- monoethylenically unsaturated carboxylic acid and an ester of an a,b- monoethylenically unsaturated carboxylic acid and of an oxyalkylenated fatty alcohol.

Preferably, according to this embodiment, the content of arginine present in the composition A is between 0.05% and 25% by weight, more preferentially between 0.1% and 15% by weight, more preferentially still between 0.5% and 10% by weight, and better still between 1% and 5% by weight, with respect to the total weight of the composition A.

Preferably, according to this embodiment, when the additional alkaline agent(s) other than arginine are present in the composition A, the total content of additional alkaline agent(s) other than arginine is between 0.05% and 25% by weight, more preferentially between 0.1% and 20% by weight and more preferentially still between 0.5% and 15% by weight, with respect to the total weight of the composition A.

Preferably, according to this embodiment, the total content of chemical oxidizing agent(s) present in the oxidizing composition B is between 0.1% and 35% by weight, more preferentially between 0.1% and 30% by weight and more preferentially still between 0.5% and 25% by weight, better still between 2% and 12% by weight, with respect to the total weight of the oxidizing composition B.

Preferably, according to this embodiment, the total content of acrylic anionic associative polymer(s) present in the oxidizing composition B is between 0.01% and 10% by weight, more preferentially between 0.05% and 5% by weight and more preferentially still between 0.075% and 3% by weight, better still between 0.1% and 2% by weight, with respect to the total weight of the oxidizing composition B.

According to yet another preferred embodiment of the invention, step a. of preparation of a composition M comprises the mixing:

- of one or more solid particles of PI type and of one or more solid particles of P2 type (and more generally of one or more particles of type PI to Pn), as described above; with

- at least one composition A comprising arginine and optionally one or more additional alkaline agents other than arginine, as described above; and

- at least one separate oxidizing composition B comprising: (i) at least one chemical oxidizing agent, preferably chosen from those as described above, more preferentially from hydrogen peroxide, persalts and their mixtures, and

(ii) one or more acrylic anionic associative polymers as described above, preferably chosen from copolymers comprising, among their monomers, an a,b- monoethylenically unsaturated carboxylic acid and an ester of an a,b- monoethylenically unsaturated carboxylic acid and of an oxyalkylenated fatty alcohol.

Preferably, according to this embodiment, the content of arginine present in the composition A is between 0.05% and 25% by weight, more preferentially between 0.1% and 15% by weight, more preferentially still between 0.5% and 10% by weight, and better still between 1% and 5% by weight, with respect to the total weight of the composition A.

Preferably, according to this embodiment, when the additional alkaline agent(s) other than arginine are present in the composition A, the total content of additional alkaline agent(s) other than arginine is between 0.05% and 25% by weight, more preferentially between 0.1% and 20% by weight and more preferentially still between 0.5% and 15% by weight, with respect to the total weight of the composition A.

Preferably, according to this embodiment, the total content of chemical oxidizing agent(s) present in the oxidizing composition B is between 0.1% and 35% by weight, more preferentially between 0.1% and 30% by weight and more preferentially still between 0.5% and 25% by weight, better still between 2% and 12% by weight, with respect to the total weight of the oxidizing composition B.

Preferably, according to this embodiment, the total content of acrylic anionic associative polymer(s) present in the oxidizing composition B is between 0.01% and 10% by weight, more preferentially between 0.05% and 5% by weight and more preferentially still between 0.075% and 3% by weight, better still between 0.1% and 2% by weight, with respect to the total weight of the oxidizing composition B.

According to an alternative form of the invention, the oxidation dye precursors as described above are present in a composition C, separate from the compositions A and B, said composition C being mixed with the compositions A and B in order to obtain the composition M. According to another specific embodiment of the invention, step a. of preparation of the composition M can additionally employ one or more dye-free solid particles.

The mixing of the oxidation dye precursors, indeed even optionally of the direct dyes, with the composition A and the oxidizing composition B, and optionally the other compositions, can be carried out by means of a mechanical stirrer, of a magnetic stirrer and/or by hand, for example using a colouring brush.

When the oxidation dye precursor(s) (indeed even the direct dye(s)) are contained in one or more solid particles, which are identical or different, as defined above, it is understood, within the meaning of the invention, that step a) of preparation of a composition M comprises the dissolution of said solid particles in the composition A and the oxidizing composition B.

Advantageously, step b) of application to the keratin fibres of the composition M according to the invention is carried out less than 60 minutes, more preferentially less than 30 minutes, more preferentially still less than 10 minutes, even better still less than 5 minutes, after step a).

The composition M

The composition M, or final composition, is obtained after the mixing of the composition A with the separate oxidizing composition B as described above.

Preferably, the water content of said composition M is between 30% and 99% by weight, more preferentially between 50% and 99% by weight, even better still between 50% and 90% by weight, with respect to the total weight of said composition

M.

Preferably, when the composition M comprises one or more oxidation dye precursors, the content of oxidation dye precursor(s) present in the composition M advantageously represents from 0.0001% to 15% by weight, more preferentially from 0.001% to 10% by weight, more preferentially still from 0.005% to 5% by weight, with respect to the total weight of the composition M. Preferably, the content of arginine present in said composition M ranges from 0.001% to 20% by weight, more preferentially from 0.05% to 10% by weight, more preferentially still from 0.1% to 5% by weight, even better still from 0.5% to 3% by weight, with respect to the total weight of said composition M.

Preferably, the total content of alkaline agent(s) present in said composition M ranges from 0.001% to 30% by weight, more preferentially from 0.05% to 20% by weight, more preferentially still from 0.5% to 10% by weight, even better still from 1% to 5% by weight, with respect to the total weight of said composition M.

Preferably, the total content of chemical oxidizing agent(s) present in said composition M ranges from 0.001% to 30% by weight, more preferentially from 0.05% to 20% by weight, and more preferentially still from 0.1% to 15% by weight, and even better still from 1% to 10% by weight, with respect to the total weight of said composition M.

Preferably, the total content of acrylic anionic associative polymer(s) present in said composition M ranges from 0.001% to 8% by weight, more preferentially from 0.005% to 4% by weight and more preferentially still from 0.01% to 1% by weight, with respect to the total weight of said composition M.

Preferably, the ratio by weight of the total weight of the composition M, on the one hand, to the total weight of solid particles, on the other hand, is between 1 and 22, more preferentially between 2 and 15, more preferentially still between 5 and 12.

The composition M can be provided in various forms, such as in the form of liquids, of creams or of gels, or in any other form appropriate for carrying out a dyeing of keratin fibres, and in particular of human hair.

Another subject-matter of the invention is a method for the preparation of a composition M for the dyeing of keratin fibres, in particular human keratin fibres, such as the hair, comprising the mixing: a) of one or more oxidation dye precursors, preferably of several solid particles, which are identical or different, each containing one or more oxidation dye precursors, more preferentially chosen from those as defined above; with b) at least one composition A comprising arginine; and c) at least one oxidizing composition B separate from the composition A comprising:

(i) one or more chemical oxidizing agents, preferably chosen from those as defined above, and

(ii) one or more acrylic anionic associative polymers, preferably chosen from the copolymers comprising, among their monomers, an a,b-monoethylenically unsaturated carboxylic acid and an ester of an a,b-monoethylenically unsaturated carboxylic acid and of an oxyalkylenated fatty alcohol.

Preferably, said solid particles comprise:

- one or more solid particles of a first type PI containing a single oxidation dye precursor Cl; and

- one or more solid particles of a second type P2 containing a single oxidation dye precursor C2; it being understood that the oxidation dye precursor C 1 is different from the oxidation dye precursor C2.

Another subject-matter of the invention is the use of the composition M as defined above for the treatment, preferably for the dyeing/bleaching, of keratin fibres, in particular human keratin fibres, such as the hair.

More particularly, the invention relates to the use of the composition M, obtained by the preparation process comprising the mixing:

- of one or more oxidation dye precursors, preferably in the form of several solid particles, which are identical or different, each containing one or more oxidation dye precursors as described above; with

- at least one composition A comprising arginine and optionally one or more additional alkaline agents other than arginine, as described above; and

- at least one separate oxidizing composition B comprising:

(i) at least one chemical oxidizing agent, preferably chosen from those as described above, more preferentially from hydrogen peroxide, persalts and their mixtures; and

(ii) one or more acrylic anionic associative polymers, preferably chosen from those as described above, more preferentially still from copolymers comprising, among their monomers, an a,b-monoethylenically unsaturated carboxylic acid and an ester of an a,b-monoethylenically unsaturated carboxylic acid and of an oxyalkylenated fatty alcohol; for the dyeing of keratin fibres, in particular human keratin fibres, such as the hair.

Another subject-matter of the invention is a composition M' for the oxidation dyeing/bleaching of keratin fibres, comprising (i) one or more acrylic anionic associative polymers, (ii) arginine, (iii) one or more chemical oxidizing agents and (iv) optionally one or more oxidation dye precursors.

The composition M' can optionally comprise (v) one or more alkaline agents other than arginine, preferably chosen from aqueous ammonia, alkanolamines, metasilicates of alkali metals or alkaline earth metals, and their mixtures, more preferentially still from aqueous ammonia, monoethanolamine, sodium metasilicate, and their mixtures.

The contents and the preferences of the compounds (i) to (v) of the ready-for- use composition M' are identical to those mentioned above for the composition M. The examples which follow serve to illustrate the invention without, however, exhibiting a limiting nature.

Examples

Example 1:

The solid particles and the compositions below according to the present invention were prepared from the ingredients, the contents of which, as percentages by weight of active material, with respect to the total weight of the solid particle or of the composition, are shown in the tables below.

Examples of particles Solid particle without upper coating layer

[Table 1]

Examples of upper coatins layer [Table 2] Examples of solid particle with upper coating layer

[Table 4]

[Table 51 [Table 6]

[Table 7]

[Table 8] Oxidizing composition

[Table 9]

Alkaline composition 1 [Table 101 Alkaline composition 2

[Table 11]

Thickening composition [Table 121 Method for dyeing keratin fibres

A composition (M) for the dyeing of keratin fibres is prepared in a bowl according to the following steps:

(1) 100 coated solid particles (i.e. 6 g) according to Table 4 above, 58 coated solid particles (i.e. 3.48 g) according to Table 6 above, 22 coated solid particles (i.e. 1.32 g) according to Table 5 above, 21 coated solid particles (i.e. 1.26 g) according to Table 7 above and 14 coated solid particles (i.e. 0.84 g) according to Table 8 above are mixed with 12 g of oxidizing composition according to Table 9 above and 36 g of water stabilized and adjusted to pH 2.2; then, after at least 30 seconds,

(2) the mixture obtained in step (1) is mixed with 24 g of thickening composition according to Table 12 above, 28.8 g of alkaline composition 1 according to Table 10 above and 19.2 g of alkaline composition 2 according to Table 11 above.

A homogeneous aqueous composition (M), where the coated solid particles have dispersed in the composition, is thus obtained.

The composition (M) obtained is subsequently applied to locks of natural Caucasian hair comprising 90% white hairs (locks of NG hair) in a proportion of 10 g of composition (M) per 1 g of hair. After a leave-in time of 30 minutes at 27°C, the locks are rinsed, washed with a standard shampoo, rinsed again and then dried.

Results for the dyeing:

The colorimetric data for each of the locks are subsequently measured in the CIELab system with a Data Color SF600X spectrophotometer (illuminant D65, angle 10° and specular component included). In this L* a* b* system, L* represents the lightness, a* indicates the green/red colour axis and b* indicates the blue/yellow colour axis. The higher the value of L*, the lighter or less intense the colour. Conversely, the lower the value of L*, the darker or more intense the colour. The higher the value of a*, the redder the shade, and the higher the value of b*, the yellower the shade.

The colour build-up on hair thus corresponds to the variation in colouring between the locks of dyed NG hair and the locks of non-dyed (i.e. untreated) NG hair, which is measured by DE according to the following equation:

In this equation, L*, a* and b* represent the values measured after dyeing of the NG hair, and Lo*, ao* and bo* represent the values measured for the locks of untreated NG hair. The higher the DE value, the better the build-up of the colouring.

The results are collated in the table below:

[Table 131

It is apparent from the results of table 13 that the keratin fibres treated with the composition (M) prepared according to the preparation process of the invention are dyed intensely and with a good colour build-up.

It has also been found that the composition (M) is easy to apply and to spread over the locks of hair, in particular without running.

Method for bleaching keratin fibres

A composition (N) for the bleaching of keratin fibres is prepared in a bowl by mixing 12 g of oxidizing composition according to Table 9 above with 36 g of water stabilized and adjusted to pH 2.2, then with 24 g of thickening composition according to Table 12 above and 48 g of alkaline composition 1 according to Table 10 above.

A homogeneous aqueous composition (N) is thus obtained.

The composition (N) obtained is subsequently applied to locks of natural Caucasian hair with a height of tone 4 (HT4) in a proportion of 10 g of composition (N) per 1 g of hair. After a leave-in time of 30 minutes at 27°C, the locks are rinsed, washed with a standard shampoo, rinsed again and then dried.

Results for the bleaching: The colour of the locks was evaluated in the CIE L* a* b* system by means of a Data Color SF600X spectrophotometer (illuminant D65, angle 10° and specular component included). In this L* a* b* system, the three parameters respectively denote the intensity of the colour (L*), the green/red colour axis (a*) and the blue/yellow colour axis (b*).

The higher the value of L*, the more the locks are bleached. The higher the value of a*, the redder the shade, and the higher the value of b*, the yellower the shade.

The effectiveness of the bleaching is evaluated by the variation in the colour of the locks before and after treatment with the composition (N), and measured by (DE*) according to the following equation:

In this equation, L*, a* and b* represent the values measured on the locks of HT4 hair treated with the composition (N), and Lo*, ao* and bo* represent the values measured on the locks of untreated HT4 hair.

The greater the value of DE*, the greater the difference in colour of the lock before and after treatment, which shows a more intensive bleaching.

The results are collated in the table below: [Table 141

It is apparent from the results of table 14 above that the keratin fibres treated with the composition (N) prepared according to the preparation process of the invention are significantly bleached (L ^* >Lo and high DE).

It has also been found that the composition (N) is easy to apply and to spread over the locks of hair, in particular without running. Example 2:

The solid particles and the compositions below were prepared from the ingredients, the contents of which, as percentages by weight of active material, with respect to the total weight of the solid particle or of the composition, are shown in the tables below.

Solid particles with upper coating layer

[Table 151 [Table 16] n

[Table 17] [Table 181

[Table 19] [Table 201

Oxidizing composition 1: [Table 211 Oxidizing composition 2

[Table 221 Alkaline composition:

[Table 231 | I | I | | | I | | | Method for dyeing keratin fibres

A composition (M2) for the dyeing of keratin fibres is prepared in a bowl according to the following steps:

(1) 25 coated solid particles (i.e. 0.47 g) according to Table 15 above, 44 coated solid particles (i.e. 0.83 g) according to Table 16 above, 4 coated solid particles (i.e. 0.04 g) according to Table 17 above, 13 coated solid particles (i.e. 0.55 g) according to Table 18 above and 5 coated solid particles (i.e. 0.1 g) according to Table 19 above and 18 coated solid particles (i.e. 0.045 g) according to Table 20 above are mixed with 6 g of oxidizing composition according to Table 21 above and 18 g of water stabilized and adjusted to pH 2.2; then, after at least 30 seconds,

(2) the mixture obtained in step (1) is mixed with 12 g of oxidizing composition B1 (invention) according to Table 22 above. Then, the mixture obtained is mixes with 24 g of alkaline composition C according to Table 23.

A homogeneous aqueous composition M2, where the coated solid particles have dispersed in the composition, is thus obtained.

A composition (M3) for the dyeing of keratin fibres is prepared in a bowl according to the following steps:

(1) 25 coated solid particles (i.e. 0.47 g) according to Table 15 above, 44 coated solid particles (i.e. 0.83 g) according to Table 16 above, 4 coated solid particles (i.e. 0.04 g) according to Table 17 above, 13 coated solid particles (i.e. 0.55 g) according to Table 18 above and 5 coated solid particles (i.e. 0.1 g) according to Table 19 above and 18 coated solid particles (i.e. 0.045 g) according to Table 20 above are mixed with 6 g of oxidizing composition according to Table 21 above and 18 g of water stabilized and adjusted to pH 2.2; then, after at least 30 seconds,

(2) the mixture obtained in step (1) is mixed with 12 g of oxidizing composition B2 (comparative) according to Table 22 above. Then, the mixture obtained is mixes with 24 g of alkaline composition C according to Table 23.

A homogeneous aqueous composition M3, where the coated solid particles have dispersed in the composition, is thus obtained.

The compositions M2 and M3 obtained is subsequently applied to locks of natural Caucasian hair comprising 90% white hairs (locks of NG hair) in a proportion of 10 g of composition (M2 or M3) per 1 g of hair. After a leave-in time of 30 minutes at 27°C, the locks are rinsed, washed with a standard shampoo, rinsed again and then dried.

Results for the dyeing:

The colorimetric data for each of the locks are subsequently measured in the CIELab system with a Konica Minolta CM-3600A spectrophotometer (illuminant D65, angle 10° and specular component included). In this L* a* b* system, L* represents the lightness, a* indicates the green/red colour axis and b* indicates the blue/yellow colour axis. The higher the value of L*, the lighter or less intense the colour. Conversely, the lower the value of L*, the darker or more intense the colour. The higher the value of a*, the redder the shade, and the higher the value of b*, the yellower the shade.

The colour build-up on hair thus corresponds to the variation in colouring between the locks of dyed NG hair and the locks of non-dyed (i.e. untreated) NG hair, which is measured by DE according to the following equation:

In this equation, L*, a* and b* represent the values measured after dyeing of the NG hair, and Lo*, ao* and bo* represent the values measured for the locks of untreated NG hair. The higher the AE value, the better the build-up of the colouring.

The results are collated in the table below: [Table 241

It is apparent from the results of table 24 that the hair treated according to the process of the invention (composition M2) is dyed more intensely and with a better colour build-up than the hair treated with the comparative process (composition M3).