Lightening dyeing process using a substrate bearing at least one oxidizing agent and an aqueous composition comprising one or more direct dyes The present invention relates to the field o f dyeing keratin fibres and more particularly to the field of hair dyeing.

The present invention relates to a process for the lightening dyeing o f keratin fibres, in particular human keratin fibres such as the hair, which consists in using on the said fibres i) a substrate comprising on its surface one or more chemical oxidizing agents, and ii) an aqueous composition comprising one or more direct dyes .

Many people have sought for a long time to modify the co lour of their hair and in particular to mask their grey hair. Essentially two types of dyeing have been developed to do this .

The first type o f dyeing is "permanent" or oxidation dyeing, which uses dye compositions containing oxidation dye precursors, generally known as oxidation bases. These oxidation bases are co lourless or weakly coloured compounds, which, when combined with oxidizing products, may give rise to coloured compounds via a process of oxidative condensation.

It is also known that the shades obtained with these oxidation bases may be varied by combining them with couplers or colouring modifiers, the latter being chosen especially from aromatic meta- diamines, meta-aminopheno ls, meta-dipheno ls and certain heterocyclic compounds such as indo le compounds. The variety o f mo lecules used as oxidation bases and couplers allows a wide range o f co lours to be obtained.

The second type o f dyeing is " semi-permanent" dyeing or direct dyeing, which consists in applying direct dyes to the keratin fibres, the said dyes being coloured and colouring mo lecules that have affinity for the fibres, and then leaving them to take, to allow the mo lecules to penetrate by diffusion to the interior o f the fibre, and then rinsing the fibres . In order to perform these co lourings, the direct dyes generally used are chosen from nitrobenzene, anthraquinone, nitropyridine, azo, xanthene, acridine, azine and triarylmethane direct dyes .

This type o f process does not require the use o f an oxidizing agent to develop the colouring . However, it is not excluded to use one in order to obtain, along with the co louring, a lightening effect. This is then referred to as direct dyeing or semi-permanent dyeing under lightening conditions .

Processes of permanent dyeing or semi-permanent dyeing under lightening conditions thus consist in using, along with the dye composition, an aqueous composition comprising at least one oxidizing agent, under alkaline pH conditions in the vast majority o f cases. The role o f this oxidizing agent is, at least in part, to degrade the melanin o f the hair, which, depending on the nature of the oxidizing agent present, leads to more or less pronounced lightening of the fibres. Thus, for relatively weak lightening, the oxidizing agent is generally hydrogen peroxide. When more pronounced lightening is desired, peroxygenated salts, for instance persulfates, are usually used in the presence of hydrogen peroxide.

However, it has been found that it is often difficult or even impossible to obtain lightening co lourings with novel visual results by using the lightening dyeing processes described previously. In particular, these processes o ften have the defect of not satisfactorily obtaining coloured patterns, which may lead to novel optical effects on the entire head of hair, which are both sharp and precise .

Furthermore, these processes o ften have the drawback o f staining the hands o f the user or of the hair stylist during the application o f the dye compositions and of the oxidizing compositions to the hair. Similarly, these processes may also give rise to undesirable stains on the user's scalp, contour of the face and/or clothing, which may be due to application errors and/or to problems o f running of the compositions used.

These processes also entail the risk of not leading to the final lightening co louring desired by the user because o f an error that may arise during the handling o f the oxidizing or dye compositions or which results from a poor choice of the starting dye compositions .

It has also been found that the shelf storage of oxidizing compositions and dye compositions may pose problems o f space occupation and/or of storage over the long term, especially in styling salons .

Moreover, it has been found that the processes o f permanent dyeing under lightening conditions may prove to be limited, especially on account of the range o f co lours that can be achieved. In particular, it is often difficult to produce very chromatic colourings .

As regards the processes o f semi-permanent dyeing under lightening conditions, they pose a problem o f compatibility between the direct dyes and the oxidizing agents, especially in the case o f peroxygenated salts . Specifically, during the mixing between the direct dyes and the oxidizing agent, the said agent may impair them by making them lose their co louring activity, which reduces the efficacy of the process. Given that such an impairment takes place gradually, the result on the co louring may vary significantly from the first lock to the last lock. It may thus be observed that areas o f the head o f hair treated first may be satisfactorily dyed, while the areas of the head o f hair treated last may be more bleached than dyed because o f the impairment of the direct dyes by the oxidizing agent.

It is already known practice from document FR 2 984 087 to use a dyeing or bleaching process which consists in placing keratin fibres in contact with a substrate bearing a bleaching or dye composition having a formulation that changes depending on the position on the said substrate, so as to obtain shaded dyeing or bleaching.

However, the said document does not describe a process that is capable of producing precise patterns and/or of leading to uniform co lourings.

There is thus a real need to perform a process for the lightening dyeing o f keratin fibres, in particular o f human keratin fibres such as the hair, which does not have the drawbacks mentioned previously, i. e . which is especially capable o f giving on the said fibres lightening co lourings that may be uniform and/or that may have novel visual results, in particular precise patterns, of reducing the problems o f space occupation and/or storage of the compositions used, o f minimizing the risks o f contact that may arise between the compositions used and the user's hands, scalp and/or clothing, and also the risks of not obtaining the desired colouring.

This aim is achieved by the present invention, one subj ect o f which is especially a process for the lightening dyeing o f keratin fibres, in particular human keratin fibres such as the hair, which consists in using on the said fibres i) a substrate comprising on its surface one or more chemical oxidizing agents, preferably in so lid form, and ii) an aqueous composition comprising one or more direct dyes.

The process for the lightening dyeing of keratin fibres thus uses a substrate onto which has been deposited one or more chemical oxidizing agents, preferably in so lid form. In other words, the substrate has been pretreated on its surface with an oxidizing composition containing one or more chemical oxidizing agents .

Thus, in the course of placing the keratin fibres in contact with the pretreated substrate and the aqueous composition, the oxidizing agents present on the surface o f the substrate and the dyes derived from the aqueous composition dissolve, in contact with the said fibres, to give lightening co lourings that may be uniform and/or co loured patterns .

In particular, the oxidizing agent(s) are deposited on the surface o f the substrate and may be localized in certain places on the said surface so as to represent one or more geometrical forms in order thereafter to produce one or more co loured patterns on the keratin fibres after contact between the said fibres, the pretreated substrate and the aqueous dye composition. In other words, the substrate may be pretreated in places with an oxidizing composition containing one or more oxidizing agents so as to be able thereafter to produce one or more coloured patterns on the fibres . The dyeing process according to the invention thus makes it possible to produce on the keratin fibres, with great precision, co loured patterns that are visually sharp . In particular, this process makes it possible to produce millimetre-sized coloured patterns having all types o f shapes, such as spots or waves, which are easily reproducible. These patterns may thus lead to novel optical effects when they are then repeated over the entire head of hair.

In other words, the process according to the invention makes it possible to obtain patterns, especially millimetre-sized patterns, homogeneously over the entire head o f hair, or in a lo calized manner on a part of the head of hair. These patterns may be imaginative from an aesthetic viewpoint or may serve to hide an irregularity in the co lour or appearance o f the keratin fibres, especially in the case o f hair regrowth or fading of the ends .

The process according to the invention can advantageously give lightened keratin fibres having sharp and precise co loured patterns, especially in the use o f an aqueous composition containing one or more direct dyes .

The process according to the invention makes it possible especially to obtain keratin fibres that are lightened from the root to the end with coloured patterns that may be located in several places on the fibre.

Specifically, the dyeing process makes it possible to lighten and dye keratin fibres more visibly at the place where the substrate comprises the oxidizing agent(s) on its surface and to dye the fibres without a lightening effect at the place where the substrate does not comprise the said oxidizing agents on its surface.

For examp le, when the substrate comprises on its surface two bands spaced apart from each other containing one or more chemical oxidizing agents and when the aqueous composition comprises one or more direct dyes, the two bands give the keratin fibres a pronounced lightening and dyeing effect, and the other areas are dyed without a lightening effect by the direct dye(s). This results in a significantly contrasted relief effect in the colouring. The process thus makes it possible to obtain lightening effects and dyeing effects that may be alternated along the keratin fibre.

The alternation between the lightening effects and the dyeing effects is advantageously obtained when the aqueous composition contains a direct dye that is sensitive to the presence of an oxidizing agent. Specifically, in this case, the activity o f the direct dye will be impaired by the oxidizing agent at the place where it is deposited on the substrate.

Moreover, by means o f using substrates comprising one or more oxidizing agents, i. e. substrates that are pretreated with a composition containing such oxidizing agents, this process makes it possible to reduce the risks of staining on the user's hands, scalp, face and/or clothing. This process also makes it possible to avoid the problems of running and/or errors in application of the compositions.

Similarly, by means of applying such pretreated substrates, this process makes it possible to reduce the problem of shelf storage of the oxidizing compositions and the dye compositions usually used in standard dyeing processes, which makes it possible to substantially reduce the problems o f space occupation. In particular, the user may have at his or her disposal a larger number o f substrates pretreated with oxidizing agents while at the same time saving space in the styling salons.

Moreover, the process according to the invention has the advantage o f using pretreated substrates that can be satisfactorily stored over a period o f time that may range, for example, from a few days to several months.

The process according to the invention also has the advantage of minimizing the risks of errors that may arise during the handling o f the compositions or in the choice o f starting compositions in order to obtain the desired colouring.

The process according to the invention also has the advantage of minimizing the risks o f impairment of the direct dyes with respect to the oxidizing agent, given that they are not formulated in the same composition. Other subj ects, characteristics, aspects and advantages o f the invention will emerge even more clearly on reading the description and the examples that follow.

As indicated previously, the lightening dyeing process uses on the said fibres a substrate that has been pretreated on its surface with a composition containing one or more chemical oxidizing agents .

The substrate used in the process o f the present invention is preferably dry.

According to the present invention, the term "dry" means that the substrate does not comprise volatiles solvents to less than 5 mg per cm ² , preferably less than 1 mg per cm ² o f the said substrate.

According to the present invention, the terms "vo latiles so lvents" mean that the so lvents have a boiling temperature of less than 140°C .

The substrate may be in the form of an element in sheet form or in another embodiment.

According to a preferred embo diment, the substrate is an element in sheet form.

According to this preferred embodiment, the substrate is preferably a dry element in sheet form.

The element in sheet form may be made of plastic, in particular thermoplastic, paper, a metal, especially aluminium, a woven, a nonwoven o f non-absorbent fibres, especially o f cellulose or a derivative thereo f, or polyamide 6,6.

Preferably, the element in sheet form is a sheet of plastic, especially o f thermoplastic, or a nonwoven material o f non-absorbent fibres, especially a nonwoven based on cellulose or a derivative thereo f.

In particular, the element in sheet form used in the dyeing process is a plastic sheet.

The element in sheet form may consist of a water-so luble material, which makes it possible, for example, to remove it by washing the hair. Preferably, the element in sheet form comprises an assembly o f a layer o f a water-so luble material and a layer o f a water-inso luble material, for example an aluminium foil.

The substrate may be designed to be able to be clo sed around a lo ck o f hair. In this case, such a substrate is, for example, provided with a fastening means for keeping it in such a state, for example an adhesive disposed clo se to one edge or a mechanical attachment relief.

Preferably, the element in sheet form has a basis weight ranging from 20 to 300 g/m ² and even more preferentially from 30 to 200 g/m ² .

The element in sheet form especially has a thickness ranging from 40 to 1000 micrometres, preferably a thickness ranging from 40 to 400 micrometres and better still from 60 to 200 micrometres.

The element in sheet form may be opaque or transparent. Preferably, the element in sheet form is transparent, which facilitates its positioning on the hair, especially when it is desired to produce one or more patterns at a precise place on the lock or on the head o f hair. In other words, the transparency o f the element in sheet form facilitates the implementation o f the lightening process, especially in the production of bleached patterns, and improves its precision.

The element in sheet form used in the dyeing process according to the invention is preferably flexible and strong. Preferentially, the strength of the sheet is greater than 300 kPa (standard TAPPI-T403) .

Preferably, the element in sheet form is water-resistant. In particular, the water absorption o f the said element is measured by the COBB 60 test which corresponds to the capacity o f the said element to absorb water during contact for 60 seconds (the procedure of which is given by standard ISO 535 , TAPPI-T41 1 measurement) .

Thus, the element in sheet form absorbs less than 100 g/m ² and preferentially less than 40 g/m ² o f water.

Preferably, the element in sheet form is resistant to oily compounds . Thus, use may be made o f a " food" paper, i. e. a complex of paper and o f po lymeric compound o f the polyethylene type or o f paper and paraffin, which is capable of acting as a barrier to water and to oils .

The element in sheet form may optionally be covered with a deposit of an adhesive composition. This adhesive layer makes it possible to improve the adhesion o f the chemical oxidizing agent(s) to the surface of the element in sheet form.

According to a preferred embodiment, the element in sheet form, after treatment with the composition containing one or more oxidizing agents, may be covered with a protection means which serves to protect the surface o f the said element from external elements. Thus, the element in sheet form comprises one or more oxidizing agents that may be covered with a protective layer. Such a protective layer makes it possible to minimize the impairment of the oxidizing agent(s) caused by moisture, light or atmospheric oxygen.

Thus, the element in sheet form may be protected by implementing processes used in paper varnishing techniques (oil varnish, acrylic varnish, etc.), and in particular by using a water-based or organic acrylic varnish composition.

In this way, the element in sheet form containing one or more oxidizing agents may be surface-protected with a layer o f acrylic varnish.

In accordance with this embodiment, the element in sheet form contains one or more oxidizing agents and is covered with a layer o f acrylic varnish. In other words, the element in sheet form contains a layer containing one or more oxidizing agents and a layer o f acrylic varnish, the two layers being juxtaposed one on the other.

The mass per unit area o f the layer o f acrylic varnish ranges from 1 to 1 0 g/m ² and more particularly from 2 to 5 g/m ² .

According to one variant, the element in sheet form is covered with a detachable protective sheet. To do this, the edges of the element in sheet form and of the protective sheet are bonded together by means of a fastening means, especially an adhesive, which may be produced via any type of method, especially by heat sealing. Thus, good cohesion is ensured between the protective sheet and the element in sheet form.

Advantageously, the protective sheet is UV-opaque to ensure better protection.

According to another variant, the element in sheet form may be covered by another protective means, namely a hermetic wrapping, defining above the element a space without oxygen (under vacuum or under an inert atmosphere) .

As indicated previously, the substrate comprises on its surface one or more chemical oxidizing agents.

The oxidizing agent(s) may be present on all or part of the surface o f the substrate. Thus, the surface o f the substrate may be entirely or partially covered with a layer containing one or more oxidizing agents. This layer represents a treatment layer of the surface of the substrate.

The expression " chemical oxidizing agent" means an oxidizing agent other than atmospheric oxygen.

The chemical oxidizing agent(s) may be chosen from hydrogen peroxide, urea peroxide, alkali metal bromates or ferricyanides, peroxygenated salts, for instance alkali metal or alkaline-earth metal persulfates, perborates and percarbonates, and also peracids and precursors thereof.

Preferably, the chemical oxidizing agent(s) are chosen from so lid chemical oxidizing agents, and more preferentially from urea peroxide, alkali metal bromates or ferricyanides, peroxygenated salts, for instance alkali metals or alkaline-earth metal persulfates, perborates and percarbonates.

Better still, the oxidizing agent(s) are chosen from hydrogen peroxide and peroxygenated salts, for instance persulfates, and mixtures thereof.

The chemical oxidizing agent(s) may be advantageously present in a content ranging from 0.01 % to 100% by weight, preferably in a content ranging from 10% to 90% by weight and better still ranging from 20% to 80% by weight relative to the weight of the treatment layer of the substrate.

The oxidizing agent(s) may be present on all or, preferably, on part of the surface of the substrate. Thus, the surface of the substrate may be entirely or partially covered with a layer containing one or more chemical oxidizing agents .

Preferably, the chemical oxidizing agent(s) are deposited on a part of the surface o f the substrate and represent patterns which, after contact with the keratin fibres and the aqueous composition containing the direct dye(s), will make it possible to produce the co loured patterns on the said fibres. In other words, the oxidizing agent(s) are deposited in the form o f patterns on the surface of the substrate. Thus, the surface o f the substrate comprises one or more oxidizing agents arranged in one or more particular geometrical forms, known as patterns, which, after contact with the aqueous composition containing the direct dye(s), lead to the production of co loured patterns on the said fibres.

The pattern(s) may have any form, especially a geometrical form.

Thus, the oxidizing agent(s) are present on a part of the surface of the substrate and represent patterns having the desired form.

The substrate may comprise on the face opposite the face bearing the oxidizing agent(s) a copy of the pattern(s) having the desired form. The production o f these patterns on the opposite face makes it possible to indicate the place where the oxidizing agent(s) may then be deposited on the surface of the substrate. Such a production facilitates thereafter the emplacement of the substrate on the keratin fibres at the place where it is desired to produce the pattern.

As a variant, such patterns are produced on the surface of the substrate before the pretreatment so as to deposit thereafter the oxidizing agent(s) directly on the patterns . In other words, the patterns that it is desired to obtain on the keratin fibres may be produced beforehand on the surface of the substrate intended to be pretreated. In both cases, the production o f patterns on the surface o f the substrate intended to be pretreated or on the surface opposite the pretreated surface is all the more advantageous when the substrate used is transparent.

In particular, the patterns may be printed beforehand on the substrate.

The substrate may also comprise on its surface one or more alkaline agents. In other words, the substrate may be pretreated with an oxidizing composition comprising one or more chemical oxidizing agents and one or more alkaline agents .

The alkaline agents may be chosen from carbonates, alkano lamines such as monoethano lamine, diethano lamine, triethanolamine and derivatives thereof, oxyethylenated and/or oxypropylenated ethylenediamines, mineral or organic hydroxides, alkali metal silicates such as sodium metasilicates, amino acids, preferably basic amino acids such as arginine, lysine, ornithine, citrulline and histidine, and the compounds of formula (I) below :

in which:

- W is a divalent (C i -Cs)alkylene group, preferably a propylene group, optionally substituted especially with a hydroxyl group or a C 1 -C4 alkyl radical;

- R _a , Rb, Rc and Rd, which may be identical or different, represent a hydrogen atom or a C 1 -C4 alkyl or C 1 -C4 hydroxyalkyl radical.

The mineral or organic hydroxides, in particular, are preferably chosen from i) hydroxides o f an alkali metal, ii) hydroxides of an alkaline-earth metal, for instance sodium hydroxide or potassium hydroxide, iii) hydroxides o f a transition metal, such as hydroxides o f metals from groups III, IV, V and VI, iv) hydroxides of lanthanides or actinides, quaternary ammonium hydroxides and guanidinium hydroxide.

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

In particular, the alkaline agents used are solid in the dry state . In a first variant of the invention, the alkaline agents are so lid before use in the oxidizing composition, and are preferably chosen from carbonates, mineral hydroxides such as so luble sodium or potassium hydroxides or silicates.

In another variant of the invention, the alkaline agents are chosen from alkano lamines, in particular monoethano lamine, diethano lamine and triethanolamine.

The alkaline agent(s) may be present in a content ranging from 0.01 % to 20% by weight relative to the total weight of the treatment layer of the surface of the substrate.

The alkaline agent(s) may be present in a content ranging from 0.01 % to 20% by weight relative to the total weight of the treatment oxidizing composition of the surface of the substrate.

The oxidizing composition may be aqueous or anhydrous .

When the oxidizing composition is aqueous and contains one or more alkaline agents, the pH preferably ranges from 7.5 to 13 , better still from 8 to 12 and even better still from 8 to 1 1 .

The substrate may also comprise one or more compounds such as acids, and in particular citric acid.

The active agent(s) may be present in a content ranging from 1 % to 20% by weight relative to the weights of the chemical oxidizing agents, both relative to the treatment composition and relative to the surface layer after pretreatment.

The oxidizing composition may contain one or more organic so lvents.

Organic so lvents that may be mentioned include linear or branched and preferably saturated monoalcohols or dio ls, comprising 2 to 6 carbon atoms, such as ethyl alcoho l, isopropyl alcoho l, hexylene glyco l (2-methyl-2,4-pentanedio l), neopentyl glyco l and 3 -methyl- 1 ,5 - pentanedio l, butylene glycol, dipropylene glycol and propylene glycol; aromatic alcoho ls such as benzyl alcoho l or phenylethyl alcoho l; polyo ls containing more than two hydroxyl functions, such as glycerol; polyo l ethers, for instance ethylene glyco l or propylene glyco l monomethyl, monoethyl or monobutyl ether; and also diethylene glyco l alkyl ethers, especially C 1 - C 4 alkyl ethers, for instance diethylene glycol monoethyl ether or monobutyl ether.

The element may also comprise on the surface o f the substrate a deposit o f one or more activators or catalysts. In particular, the substrate comprises a deposit of one or more metal salts in a content ranging from 1 % to 20% by weight relative to the weights o f the chemical oxidizing agents .

The substrate used in the process according to the invention is pretreated with an oxidizing composition containing one or more oxidizing agents .

Preferably, the substrate is pretreated with an oxidizing composition containing one or more oxidizing agents and one or more alkaline agents .

The oxidizing composition may be liquid or in powder form, preferably in powder form.

The oxidizing composition deposited on the surface o f the substrate may optionally result from successive treatments of the substrate with one or more oxidizing agents, on the one hand, one or more alkaline agents, on the other hand, and optionally one or more active agents as described previously.

As indicated previously, the dyeing process uses an aqueous composition comprising one or more direct dyes which interact with the substrate comprising on its surface one or more oxidizing agents .

The term " direct dye" means natural and/or synthetic dyes, other than oxidation dyes . These are dyes that will spread superficially on the fibre. The direct dyes may be anionic, nonionic or cationic .

They are preferably cationic or nonionic, either as a mixture or as individual dyes. Mention may be made, as direct dye according to the invention, of the fo llowing dyes : acridines; acridones; anthranthrones; anthrapyrimidines; anthraquinones; azines; (poly)azos, hydrazono or hydrazones, in particular arylhydrazones; azomethines; benzanthrones; benzimidazoles; benzimidazolones; benzindo les; benzoxazo les; benzopyrans; benzothiazoles; benzoquinones; bisazines; bis- isoindo lines; carboxanilides; coumarins; cyanines, such as azacarbocyanines, diazacarbocyanines, diazahemicyanines, hemicyanines or tetraazacarbocyanines; diazines; diketopyrrolopyrroles; dioxazines; diphenylamines; diphenylmethanes; dithiazines; flavonoids, such as flavanthrones and flavones; fluorindines; formazans; indamines; indanthrones; indigoids and pseudoindigoids; indopheno ls; indoanilines; isoindo lines; isoindo linones; isovio lanthrones; lactones; (poly)methines, such as dimethines o f stilbene or styryl types; naphthalimides; naphthanilides; naphtho lactams; naphthoquinones; nitro , in particular nitro(hetero)aromatics; oxadiazoles; oxazines; perilones; perinones; perylenes; phenazines; phenoxazines; phenothiazines; phthalocyanines; polyenes/carotenoids; porphyrins; pyranthrones; pyrazolanthrones; pyrazolones; pyrimidinoanthrones; pyronines; quinacridones; quino lines; quinophthalones; squaranes; tetrazoliums; thiazines; thioindigos; thiopyronines; triarylmethanes or xanthenes.

More particularly, the direct dyes o f the invention are chosen from neutral, acidic or cationic nitrobenzene direct dyes, neutral, acidic or cationic azo direct dyes, tetraazapentamethine dyes, neutral, acidic or cationic quinone and in particular anthraquinone dyes, azine direct dyes, triarylmethane direct dyes, azomethine direct dyes and natural direct dyes.

According to one embodiment, the direct dyes o f the invention are anionic. These anionic direct dyes are dyes commonly known as "acid dyes" for their affinity with alkaline substances (see, for example, Industrial Dyes, Chemistry, Properties, Application, Klaus Hunger Ed. Wiley-VCH Verlag GmbH & Co . KGaA, Weinheim 2003 ) . Anionic or acid dyes are known in the literature (see, for examp le, Ullman 's Encyclopedia of Industrial Chemistry, Azo Dyes, 2005 Wiley-VCH Verlag GmbH & Co . KGaA, Weinheim 10. 1002/ 14356007. a03 245 , point 3.2; ibid, Textile Auxiliaries, 2002 Wiley-VCH Verlag GmbH & Co . KGaA, Weinheim 10. 1002/ 14356007. a26 227 and Ashford's Dictionary of Industrial Chemicals, S econd Edition, p . 14-p . 39, 2001 ).

The term "anionic direct dye" means any direct dye comprising in its structure at least one sulfonate S03 - group and/or at least one carboxylate group C(0)0- and optionally one or more anionic groups G- with G-, which may be identical or different, representing an anionic group chosen from alkoxide 0-, thio late S-, carboxylate and thiocarboxylate : C(Q)Q ' -, with Q and Q ' , which may be identical or different, representing an oxygen or sulfur atom; preferably, G- represents a carboxylate, i. e. Q, and Q ' represents an oxygen atom.

The preferred anionic dyes are chosen from acidic nitro direct dyes, acidic azo dyes, acidic azine dyes, acidic triarylmethane dyes, acidic indoamine dyes, acidic anthraquinone dyes, indigoid dyes and acidic natural dyes, each o f these dyes containing at least one sulfonate or carboxylate group .

As anionic dyes according to the invention, mention may be made o f the dyes o f formulae (II), (ΙΓ), (III), (ΙΙΓ ), (IV), (IV ), (V), (V ), (VI), (VII), (VIII) and (IX) below:

a) the diaryl anionic azo dyes of formula (II) or (ΙΓ) :

in which formulae (II) and (ΙΓ):

R7, R8, R9, RIO, R'7, R'8, R'9 and R'lO, which may be identical or different, represent a hydrogen atom or a group chosen from: alkyl;

alkoxy, alkylthio;

hydroxyl, mercapto;

- nitro;

- R°-C(X)-X'-, R°-X'-C(X)-, R°-X'-C(X)-X"- with R° representing a hydrogen atom or an alkyl or aryl group; X, X' and X", which may be identical or different, representing an oxygen or sulfur atom, or NR with R representing a hydrogen atom or an alkyl group;

(0)2S(0-)-, M+ with M+ representing a cationic counterion such as an alkali metal (Na, K) or an alkaline-earth metal (Ca);

- (O)CO--, M+ with M+ as defined previously;

R"-S(0)2-, with R" representing a hydrogen atom or an alkyl, aryl, (di)(alkyl)amino or aryl(alkyl)amino group; preferentially a phenylamino or phenyl group;

R" '-S(0)2-X'- with R"' representing an alkyl or optionally substituted aryl group, X' as defined previously;

(di)(alkyl)amino;

aryl(alkyl)amino optionally substituted with one or more groups chosen from i) nitro; ii) nitroso; iii) (0)2S(0-)-, M+ and iv) alkoxy with M+ as defined previously;

optionally substituted heteroaryl; preferentially a benzothiazolyl group;

cycloalkyl; especially cyclohexyl;

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

or alternatively two contiguous groups R7 with R8 or R8 with R9 or R9 with RIO together form a fused benzo group A'; and R'7 with R'8 or R'8 with R'9 or R'9 with R'lO together form a fused benzo group B'; with A' and B' optionally substituted with one or more groups chosen from i) nitro; ii) nitroso; iii) (0)2S(0-)-, M+; iv) hydroxyl; v) mercapto; vi) (di)(alkyl)amino; vii) R°-C(X)-X'-; viii) R°-X'-C(X)-; ix) R°- X'-C(X)-X"-; x) Ar-N=N- and xi) optionally substituted aryl(alkyl)amino; with M+, R°, X, X', X" and Ar as defined previously;

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

it being understood that formulae (II) and (ΙΓ) comprise at least one sulfonate (0)2S(0-)-, M+ or carboxylate (O)C(O-)-, M+ radical on one of the rings A, A', B, B' or C with M+ as defined previously;

as examples of dyes of formula (II), mention may be made of Acid Red 1, Acid Red 4, Acid Red 13, Acid Red 14, Acid Red 18, Acid Red 27, Acid Red 32, Acid Red 33, Acid Red 35, Acid Red 37, Acid Red 40, Acid Red 41, Acid Red 42, Acid Red 44, Acid Red 68, Acid Red 73, Acid Red 135, Acid Red 138, Acid Red 184, Food Red 1, Food Red 13, Acid Orange 6, Acid Orange 7, Acid Orange 10, Acid Orange

19, Acid Orange 20, Acid Orange 24, Acid Yellow 9, Acid Yellow 36, Acid Yellow 199, Food Yellow 3; Acid Violet 7, Acid Violet 14, Acid

Blue 113, Acid Blue 117, Acid Black 1, Acid Brown 4, Acid Brown

20, Acid Black 26, Acid Black 52, Food Black 1 and Food Black 2; and as examples of dyes of formula (ΙΓ), mention may be made of Acid Red 111, Acid Red 134 and Acid yellow 38;

b) the pyrazolone anionic azo dyes of formulae (III) and (ΙΙΓ):

in which formulae (III) and (ΠΓ) :

□ Rl l , R12 and R 13 , which may be identical or different, represent a hydrogen or halo gen atom, an alkyl group or -(0)2S(0-), M+ with M+ as defined previously;

□ R14 represents a hydrogen atom, an alkyl group or a group - C(0)0-, M+ with M+ as defined previously;

□ R 15 represents a hydrogen atom;

□ R16 represents an oxo group, in which case R' 1 6 is absent, or alternatively R1 5 with R16 together form a double bond;

□ R17 and R 1 8 , which may be identical or different, represent a hydrogen atom, or a group chosen from:

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

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

□ R19 and R20, together form either a double bond, or a benzo group D', which is optionally substituted;

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

□ R21 represents a hydrogen atom or an alkyl or alkoxy group ; □ Ra and Rb, which may be identical or different, are as defined previously, preferentially Ra represents a hydrogen atom and Rb represents an aryl group;

□ Y represents either a hydroxyl group or an oxo group;

H— represents a single bond when Y is an oxo group; and represents a double bond when Y represents a hydroxyl group;

it being understood that formulae (III) and (ΙΙΓ) comprise at least one sulfonate group (0)2S(0-)-, M+ on one of the rings D or E or formulae (III) and (ΙΙΓ) comprise at least one carboxylate group (O)C(O-)-, M+ with M+ as defined previously;

as examples o f dyes of formula (III), mention may be made o f Acid Red 1 95 , Acid Yellow 23 , Acid Yellow 27, Acid Yellow 76 , and, as examples o f dyes of formula (ΙΙΓ), mention may be made of the ammonium salt derived from Acid Yellow 17 ;

c) the anthraquinone dyes of formulae (IV) and (IV) :

in which formulae (IV) and (IV) :

□ R22, R23 , R24, R25 , R26 and R27, which may be identical or different, represent a hydrogen or halogen atom, or a group chosen from:

- alkyl;

- hydroxyl, mercapto;

- alkoxy, alkylthio ;

- aryloxy or arylthio optionally substituted, preferentially substituted with one or more groups chosen from alkyl and (0)2S(0-)-, M+ with M+ as defined previously; - aryl(alkyl)amino optionally substituted with one or more groups chosen from alkyl and (0)2S(0-)-, M+ with M+ as defined previously;

- (di)(alkyl)amino;

- (di)(hydroxyalkyl)amino;

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

□ Z ' represents a hydrogen atom or a group NR28R29 with R28 and R29, which may be identical or different, representing a hydrogen atom or a group chosen from:

- alkyl;

- polyhydroxyalkyl such as hydroxyethyl;

- aryl optionally substituted with one or more groups, particularly i) alkyl such as methyl, n-dodecyl, n-butyl; ii) (0)2S(0-)-, M+ with M+ as defined previously; iii) R°-C(X)-X ' -, R°-X ' -C(X)-, R°- X' -C(X)-X " - with R° , X, X' and X" as defined previously, preferentially R° represents an alkyl group;

- cycloalkyl; especially cyclohexyl;

□ Z, represents a group chosen from hydroxyl and NR' 28R' 29 with R'28 and R' 29, which may be identical or different, representing the same atoms or groups as R28 and R29 as defined previously;

it being understood that formulae (IV) and (IV) comprise at least one sulfonate group (0)2S(0-)-, M+ with M+ as defined previously;

as examples o f dyes o f formula (IV), mention may be made o f Acid Blue 25 , Acid Blue 43 , Acid Blue 62, Acid Blue 78 , Acid Blue 129 , Acid Blue 138 , Acid Blue 140, Acid Blue 25 1 , Acid Green 25 , Acid Green 41 , Acid Vio let 42, Acid Vio let 43 and Mordant Red 3 ;

and as an example o f a dye o f formula (IV), mention may be made of the ammonium salt derived from Acid Black 48 ;

d) the dyes corresponding to formulae (V) and (V) below:

in which formulae (V) and (V) :

□ R30, R3 1 and R32, which may be identical or different, represent a hydrogen or halogen atom, or a group chosen from:

- alkyl;

- alkoxy optionally substituted with one or more hydroxyl groups, alkylthio optionally substituted with one or more hydroxyl groups;

- hydroxyl, mercapto;

- nitro , nitroso ;

- (poly)haloalkyl;

- R°-C(X)-X ' -, R°-X ' -C(X)-, R°-X ' -C(X)-X" - with R° ; X, X ' and X " as defined previously;

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

- (O)CO--, M+ with M+ as defined previously;

- (di)(alkyl)amino;

- (di)(hydroxyalkyl)amino;

- heterocycloalkyl such as piperidino , piperazino or morpholino; in particular, R30, R3 1 and R32 represent a hydrogen atom;

□ Rc and Rd, which may be identical or different, represent a hydrogen atom or an alkyl group ;

□ W is as defined previously; W particularly represents a group -

NH-; □ ALK represents a linear or branched divalent C 1 -C6 alkylene group; in particular, ALK represents a group -CH2-CH2- ;

□ n is 1 or 2;

□ p represents an integer between 1 and 5 inclusively;

□ q represents an integer between 1 and 4 inclusively;

□ u is 0 or 1 ;

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

□ when n is 2, J represents an oxygen or sulfur atom, or a divalent radical -S(0)m- with m representing an integer 1 or 2 ; preferentially J represents a radical -S02-;

□ M' is as defined previously for M+; may be present or absent, represents a benzo group optionally substituted with one or more groups R30 as defined previously;

it being understood that formulae (V) and (V) comprise at least one sulfonate group (0)2S(0-)-, M+ or carboxylate group (O)C(O-)-, M+ with M+ as defined previously;

as examples o f dyes o f formula (V), mention may be made o f: Acid Brown 13 and Acid Orange 3 ; as examples of dyes of formula (V), mention may be made o f: Acid Yellow 1 , sodium salt o f 2,4-dinitro- 1 - naphtho l-7-sulfonic acid, 2-piperidino-5 -nitrobenzenesulfonic acid, 2- (4 '-N,N(2 "-hydroxyethyl)amino -2 '-nitro) anilineethane sulfonic acid and 4- -hydroxyethylamino-3 -nitrobenzenesulfonic acid;

e) the triarylmethane dyes of formula (VI) :

in which formula (VI) :

□ R33 , R34, R35 and R36, which may be identical or different, represent a hydrogen atom or a group chosen from alkyl, optionally substituted aryl and optionally substituted arylalkyl; particularly an alkyl group and benzyl optionally substituted with a group (O)mS(O-)-, M+ with M+ and m as defined previously;

□ R37, R38 , R39, R40, R41 , R42, R43 and R44, which may be identical or different, represent a hydrogen atom or a group chosen from:

- alkyl;

- alkoxy, alkylthio ;

- (di)(alkyl)amino;

- hydroxyl, mercapto;

- nitro , nitroso ;

- R°-C(X)-X ' -, R°-X' -C(X)-, R°-X' -C(X)-X" - with R° representing a hydrogen atom or an alkyl or aryl group; X, X' and X" , which may be identical or different, representing an oxygen or sulfur atom, or NR with R representing a hydrogen atom or an alkyl group;

- (0)2S(0-)-, M+ with M+ representing a hydrogen atom or a cationic counterion;

- (O)CO--, M+ with M+ as defined previously;

- or alternatively two contiguous groups R41 with R42 or R42 with R43 or R43 with R44 together form a fused benzo group : Γ ; with Γ optionally substituted with one or more groups chosen from i) nitro; ii) nitroso; iii) (0)2S(0-)-, M+; iv) hydroxyl; v) mercapto; vi) (di)(alkyl)amino; vii) R°-C(X)-X'-; viii) R°-X'-C(X)-; ix) R°-X'-C(X)- X"-; with M+, R°, X, X', X" as defined previously;

particularly, R37 to R40 represent a hydrogen atom, and R41 to R44, which may be identical or different, represent a hydroxyl group or (0)2S(0-)-, M+; and when R43 with R44 together form a benzo group, it is preferentially substituted with a group (0)2S(0-)-;

it being understood that at least one of the rings G, H, I or Γ comprises at least one sulfonate (0)2S(0-)-, M+ or carboxylate (O)C(O- )-, M+ group with M+ as defined previously;

as examples of dyes of formula (VI), mention may be made of: Acid Blue 1; Acid Blue 3; Acid Blue 7, Acid Blue 9; Acid Violet 49 and Acid Green 50;

f) the xanthene-based dyes of formula (VII):

in which formula (VII):

□ R45, R46, R47 and R48, which may be identical or different, represent a hydrogen atom or a halogen atom;

□ R49, R50, R51 and R52, which may be identical or different, represent a hydrogen or halogen atom or a group chosen from:

- alkyl;

- alkoxy, alkylthio;

- hydroxyl, mercapto;

- nitro, nitroso;

- (0)2S(0-)-, M+ with M+ representing a hydrogen atom or a cationic counterion;

- (O)CO--, M+ with M+ as defined previously; particularly R53 R54, R55 and R48 represent a hydrogen or halogen atom;

□ G represents an oxygen or sulfur atom or a group NRe with Re as defined previously; particularly G represents an oxygen atom;

□ L represents an alkoxide 0-, M+; a thioalkoxide S-, M+ or a group NRf, with Rf representing a hydrogen atom or an alkyl group, and M+ as defined previously; M+ is particularly sodium;

□ L ' represents an oxygen or sulfur atom or an ammonium group : N+RfRg, with Rf and Rg, which may be identical or different, representing a hydrogen atom, an alkyl group, optionally substituted aryl; L ' represents particularly an oxygen atom or a phenylamino group optionally substituted with one or more alkyl or (O)mS(O-)-, M+ groups with m and M+ as defined previously;

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

□ M ⁺ is as defined previously;

it being understood that formula (VII) comprises at least one sulfonate group (0)2S(0-)-, M+ or carboxylate group (O)C(O-)-, M+ with M+ as defined previously;

as examples o f dyes o f formula (VII), mention may be made o f:

Acid Yellow 73 ; Acid Red 5 1 ; Acid Red 87; Acid Red 92 ; Acid Red 95 and Acid Vio let 9;

g) the indole-based dyes of formula (VIII) :

□ R53 , R54, R55 , R56, R57, R58 , R59 and R60, which may be identical or different, represent a hydrogen atom or a group chosen from:

- alkyl;

- alkoxy, alkylthio ;

- hydroxyl, mercapto;

- nitro , nitroso ; - R°-C(X)-X ' -, R°-X' -C(X)-, R°-X' -C(X)-X" - with R° representing a hydrogen atom or an alkyl or aryl group; X, X' and X" , which may be identical or different, representing an oxygen or sulfur atom, or NR with R representing a hydrogen atom or an alkyl group;

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

- (O)CO--, M+ with M+ as defined previously;

□ G represents an oxygen or sulfur atom or a group NRe with Re as defined previously; particularly G represents an oxygen atom;

□ Ri and Rh, which may be identical or different, represent a hydrogen atom or an alkyl group ;

it being understood that formula (VIII) comprises at least one sulfonate group (0)2S(0-)-, M+ or carboxylate group (O)C(O-)-, M+ with M+ as defined previously;

as an example o f a dye of formula (VIII), mention may be made of the ammonium salt derived from: Acid Blue 74;

h) the quinoline-based dyes of formula (IX) :

□ R61 represents a hydrogen or halogen atom or an alkyl group;

□ R62, R63 and R64, which may be identical or different, represent a hydrogen atom or a group (0)2S(0-)-, M+ with M+ as defined previously;

□ or alternatively R61 with R62, or R6 1 with R64 , together form a benzo group optionally substituted with one or more groups (0)2S(0-)- , M+ with M+ representing a hydrogen atom or a cationic counterion; it being understood that formula (IX) comprises at least one sulfonate group (0)2S(0-)-, M+ with M+ as defined previously;

as examples o f dyes o f formula (IX), mention may be made o f: Acid Yellow 2, Acid Yellow 3 and Acid Yellow 5. More particularly, the anionic direct dyes that are useful in the invention may be chosen from the following dyes :

ntro an neet anesu on c ac e ong ng to ormu a

Most of these dyes are described in particular in the Colour

Index published by The Society of Dyers and Colourists, P.O. Box 244, Perkin House, 82 Grattan Road, Bradford, Yorkshire, BD1 2JBN England.

The anionic dyes that are most particularly preferred are the dyes designated in the Colour Index under the code C.I. 58005 (monosodium salt of 1 ,2-dihydroxy-9, 10-anthraquinone-3-sulfonic acid), C.I. 60730 (monosodium salt of 2-[(9, 10-dihydro-4-hydroxy- 9, 10-dioxo- 1 - anthracenyl)amino]-5-methylbenzenesulfonic acid), C.I. 15510 (monosodium salt of 4-[(2-hydroxy- 1 - naphthyl)azo]benzenesulfonic acid), C.I. 15985 (disodium salt of 6- hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonic acid), C.I. 17200 (disodium salt of 5-amino-4-hydroxy-3-(phenylazo)-2,7- naphthalenedisulfonic acid), C.I. 20470 (disodium salt of l-amino-2- (4'-nitrophenylazo)-7-phenylazo-8-hydroxy-3,6-naphthalenedis ulfonic acid), C.I. 42090 (disodium salt of N-ethyl-N-[4-[[4-[ethyl[3- (sulfophenyl)methyl]amino]phenyl](2-sulfophenyl)methylene]-2 ,5- cyclohexadien- 1 -ylidene]-3-sulfobenzenemethanaminium hydroxide, inner salt), C.I. 61570 (disodium salt of 2,2 ^* -[(9, 10-dihydro-9, 10- dioxo- 1 ,4-anthracenediyl)diimino]bis[5-methyl]benzenesulfonic acid). It is also possible to use compounds corresponding to the mesomeric or tautomeric forms of structures (II) to (IX).

More preferentially, the anionic dyes of formula (I) according to the invention are chosen from those of formulae (II), (III) and (IV).

According to a particular embodiment of the invention, the direct dyes of the invention are chosen from those corresponding to formulae (Ha), (Ilia) and (IVa) below:

in which formula (Ha):

□ R7, R8, R9, RIO, R'7, R'8, R'9 and R'lO, which may be identical or different, represent a hydrogen atom or a group chosen from:

- hydroxyl;

- nitro, nitroso;

- (di)(alkyl)amino;

- (0)2S(0-)-, M+ with M+ representing a hydrogen atom or a cationic counterion as defined previously; and

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

- or alternatively two contiguous groups R7 with R8 or R8 with R9 or R9 with RIO together form a fused benzo group A'; and R'7 with R'8 or R'8 with R'9 or R'9 with R'lO together form a fused benzo group B'; with A' and B' optionally substituted with one or more groups chosen from a) (0)2S(0-)-, M+; b) hydroxyl; c) Ar-N=N-; with M+ and Ar as defined previously;

in which formula (Ilia) :

□ Rl l , R12 and R 13 , which may be identical or different, represent a hydrogen or halo gen atom, an alkyl group or -(0)2S(0-), M+ with M+ as defined previously;

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

□ R16, R17, R1 8 , R19 and R20, which may be identical or different, represent a hydrogen atom or an alkyl, hydroxyl or (0)2S(0-)-, M+ group with M+ as defined previously;

□ Y represents either a hydroxyl group or an oxo group;

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

it being understood that formula (Ilia) comprises at least one sulfonate group (0)2S(0-)-, M+ on one of the rings D or E or carboxylate (O)C(O-)-,

in which formula (IVa) :

□ Z ' represents a group NR28R29 with R28 representing a hydrogen atom or an alkyl group and R29 representing an aryl group optionally substituted particularly with one or more groups chosen from i) alkyl such as methyl and ii) (0)2S(0-)-, M+ with M+ as defined previously; □ Z, represents a group chosen from hydroxyl and NR' 28R' 29 with R' 28 and R' 29, which may be identical or different, representing the same atoms or groups as R28 and R29 as defined previously;

it being understood that formula (IVa) comprises at least one sulfonate group (0) ₂ S(0-)-, M+;

examples that may be mentioned include the fo llowing anionic dyes :

Acid Yellow 23

(belonging to formulae (III) and (Ilia))

0 OH

Acid Violet 43

(belonging to formulae (IV) and (IVa)) with M+, which may be identical or different, being a cationic counterion as defined previously.

According to a particular embodiment of the invention, the direct dyes are benzene-based dyes that are usually neutral. More preferentially, the benzene-based direct dyes of the invention are chosen from the compounds of formula (X) below:

in which formula (X):

R18 represents an amino radical; an amino radical monosubstituted or disubstituted with a C1-C4 alkyl, C1-C4 monohydroxyalkyl, C2-C4 polyhydroxyalkyl, C1-C4 aminoalkyl, mono(Cl-C4)alkylamino(Cl-C4)alkyl, di(C 1 -C4)alkylamino(C 1 -

C4)alkyl, C1-C4 ureidoalkyl, aryl radical, aryl in which the aryl ring is substituted with one or more hydroxyl, carboxyl, amino or di(Cl- C4)alkylamino radicals,

- R19 represents a hydrogen atom; an amino radical; a hydroxyl radical; a C1-C4 alkyl radical; a C1-C4 alkoxy radical; a C1-C4 monohydroxyalkyl radical; a C2-C4 polyhydroxyalkyl radical; a C1-C4 monohydroxyalkoxy radical; a C2-C4 polyhydroxyalkoxy radical; a C1-C4 aminoalkoxy radical; an amino radical monosubstituted or disubstituted with a C1-C4 alkyl, C1-C4 monohydroxyalkyl, C2-C4 polyhydroxyalkyl, C1-C4 aminoalkyl, mono(Cl-C4)alkylamino(Cl-C4)alkyl, di(C 1 -C4)alkylamino(C 1 -

C4)alkyl, C1-C4 ureidoalkyl, aryl radical, aryl in which the aryl ring is substituted with one or more hydroxyl, carboxyl, amino or di(Cl- C4)alkylamino radicals,

- R20 represents a hydrogen or halogen atom, a C1-C4 alkyl radical or a nitro group.

Among the nitrobenzene dyes of formula (X) above, mention may be made most particularly of: 2-amino-4-methyl-5-N-( - hydroxyethyl)aminonitrobenzene; 4-Ν-(β- urei do ethyl) aminonitrobenzene; 4 -(N-ethyl-N- β- hydroxy ethyl)amino- 1 -N-( -hydroxyethyl)aminonitrobenzene; 2-N-(P-hydroxyethyl)amino- 5-methylnitrobenzene; 5-chloro-3-N-(ethyl)amino-4- hydroxynitrobenzene; 5-amino-3-chloro-4-hydroxynitrobenzene; 2-N- (y-hydroxypropyl)amino-5-N,N-bis( - hydroxy ethyl) aminonitrobenzene; 5-hydroxy-2-N-(y- hydroxypropyl)aminonitrobenzene; 1 ,3-bis(P-hydroxyethyl)amino-4- chloro-6-nitrobenzene; 2,4-diaminonitrobenzene; 3,4- diaminonitrobenzene; 2,5-diaminonitrobenzene; 3-amino-4- hydroxynitrobenzene; 4-amino-3-hydroxynitrobenzene; 5-amino-2- hydroxynitrobenzene; 2-amino-5-hydroxynitrobenzene; 4-amino-3- hydroxynitrobenzene; 5-amino-2-hydroxynitrobenzene; 2-amino-3- hydroxynitrobenzene; 2-amino-5-N-(P- hydroxy ethyl) aminonitrobenzene; 2-amino-5-N,N-bis( - hydroxy ethyl) aminonitrobenzene; 2,5-Ν,Ν'-(β- hydroxy ethyl) aminonitrobenzene; 2 -N- (β -hydroxy ethyl) amino- 5 -N,N- bis(P -hydroxy ethyl) aminonitrobenzene; 2 -amino- 5 -N-

(methyl)aminonitrobenzene; 2 -N- (methyl) amino -5 -N,N-bis( - hydro xyethyl)aminonitrobenzene; 2-N-(methyl)amino-5 -(N-methyl-N- P-hydroxyethyl)aminonitrobenzene; 2,5 -Ν,Ν'-(β- hydroxyethyl)aminonitrobenzene; 2-N-(P-hydroxyethyl)amino-5 - hydroxynitrobenzene; 3 -methoxy-4-N-(P- hydroxyethyl)aminonitrobenzene; 2-N-(methyl)amino-4- - hydroxyethyloxynitrobenzene; 2-amino-3 -methylnitrobenzene; 2-N- (P-hydroxyethyl)amino -5 -aminonitrobenzene; 2-amino-4-chloro-5 -N- ( -hydroxyethyl)aminonitrobenzene; 2-amino-4-methyl-5 -N-(P- hydroxyethyl)aminonitrobenzene; 2 -amino -4 -methyl- 5 -N-

(methyl)aminonitrobenzene; 2-Ν-(β -hydroxy ethyl) amino -5 - met hoxynitro benzene; 2-amino-5 -P-hydroxyethyloxynitrobenzene; 2- Ν-(β -hydroxy ethyl) amino nitrobenzene; 3 -amino-4-N-( - hydroxyethyl)aminonitrobenzene; 3 - -hydroxyethyloxy-4-N-( - hydroxyethyl)aminonitrobenzene; 2 -N- (methyl) amino -4- β , γ- dihydroxypropyloxy nitrobenzene; 2-N-( -hydroxyethyl)amino-5 - - hydroxyethyloxy nitrobenzene; 2-N-( β -hydroxy ethyl)amino -5 - β , γ- dihydroxypropyloxy nitrobenzene; 2-hydroxy-4-N-( - hydro xyethyl)aminonitrobenzene; 2 -N- (methyl) amino -4 -methyl- 5 - amino nitrobenzene; 2-amino-4-isopropyl-5 -N- (methyl)aminonitrobenzene; 2-N-(methyl)amino-5 -(N-methyl-N- ,y- dihydroxypropyl)aminonitro benzene; 3 -Ν-(β -hydroxy ethyl) amino -4 - Ν-(β -hydroxy ethyl) amino nitrobenzene; 2-amino-4-methyl-5 -N-(P ,y- dihydroxypropyl)aminonitrobenzene; 2-amino-4-methyl-5 - hydroxynitrobenzene; 2-Ν-(β -hydro xy ethyl) amino -4-Ν-(β - hydro xyethyl)aminonitrobenzene; 2-amino-5 -N-( - amino ethyl) aminonitrobenzene; 2-N-( -aminoethyl)amino-5 - met hoxynitro benzene; 2-N-(methyl)amino-5 -N-( - aminoethyl)aminonitrobenzene; 2-N-( -aminoethyl)amino-4-N,N- (dimethyl) amino nitrobenzene; 3 -amino-4-N-( - amino ethyl) aminonitrobenzene; 2-amino-4-methyl-5 -N-( - amino ethyl) aminonitrobenzene; 2-N-( -aminoethyl)amino-5 -N,N- bis( -hydroxy ethyl) aminonitrobenzene; 3 - -aminoethyloxy-4- amino nitrobenzene; 2-N-(methyl)amino-5-(N-5-amino-n- butyl) amino nitrobenzene; 2-N-(y-amino-n-propyl)amino-5-N,N- (dimethyl) amino nitrobenzene; 3-methoxy-4-N-(P- amino ethyl) aminonitrobenzene; 2-N-( -aminoethyl)amino-5- aminonitrobenzene; 2-amino-4-chloro-5-N-( - amino ethyl) aminonitrobenzene; 2-N-( -aminoethyl)amino-4- methoxynitro benzene; 2-N-( -aminoethyl)aminonitrobenzene; 2-Ν-(β- aminoethyl)amino-5-N-( -aminoethyl)aminonitrobenzene; 2-Ν-(β- aminoethyl)amino-4- -hydroxyethyloxynitrobenzene; 3-β- hydro xyethyloxy-4-N-( -aminoethyl)aminonitrobenzene; 2- amino -5- amino ethyloxy nitrobenzene; 3-hydroxy-4-N-( - amino ethyl) aminonitrobenzene; 2-N-( -aminoethyl)amino-5- - hydroxy ethyloxy nitrobenzene; 2-N-( -aminoethyl)amino-4- hydroxynitrobenzene; 2-[2-hydroxy-3-N-( -hydroxyethyl)amino-6- nitro]benzyloxy]ethylamine and 2-[2-hydroxy-3-N-( - hydro xypropyl) amino- 6 -nitro]benzyloxy]ethylamine.

Among the nitrobenzene dyes of formula (X) above, the following are most particularly preferred: 2-amino-4-methyl-5-N-( - hydroxy ethyl) aminonitrobenzene; 4-Ν-(β- urei do ethyl) aminonitrobenzene; 4 -(N-ethyl-N- β- hydroxy ethyl)amino- 1 -Ν-(β -hydroxy ethyl) amino nitrobenzene; 2 -Ν-(β -hydroxy ethyl) amino - 5-methylnitrobenzene; 5-chloro-3-N-(ethyl)amino-4- hydroxynitrobenzene; 5-amino-3-chloro-4-hydroxynitrobenzene; 2-N- (γ-hydroxypropyl)amino-5-N,N-bis(β- hydroxyethyl)aminonitrobenzene; 5-hydroxy-2-N-(y- hydro xypropyl) amino nitrobenzene; 1 , 3 -bis^ -hydroxy ethyl) amino -4- chloro-6-nitrobenzene; 3,4-diaminonitrobenzene; 2-amino-5- hydroxynitrobenzene; 2-amino-3-hydroxynitrobenzene; 2 -amino -5 -N- (β -hydroxy ethyl) amino nitrobenzene; 2-amino-5-N,N-bis^- hydroxy ethyl) aminonitrobenzene; 2 -Ν-(β -hydroxy ethyl) amino -5 -N, N- bis( -hydroxy ethyl) aminonitrobenzene; 2 -Ν-(β -hydroxy ethyl) amino - 5-hydroxynitrobenzene; 2-Ν-(β -hydroxy ethyl) amino -5 - aminonitrobenzene; 2-N-^-aminoethyl)amino-4- methoxynitrobenzene; and 2-N-(P-aminoethyl)amino-5-P- hydroxyethyloxy nitrobenzene.

According to a particular embodiment, the direct dye(s) are chosen from porphyrins and phthalocyanines, alone or as mixtures.

According to a particular embo diment, the direct dye(s) o f the invention are cationic.

Examples o f suitable direct dyes that may be mentioned include azo direct dyes; (poly)methine dyes such as cyanines, hemicyanines and styryl dyes; carbonyl dyes; azine dyes; nitro(hetero)aryl dyes; tri(hetero)arylmethane dyes; porphyrin dyes; phthalocyanine dyes, and natural direct dyes, alone or as mixtures.

Preferentially, the direct dye(s) contain at least one quaternized cationic chromophore or at least one chromophore bearing a quaternized or quaternizable cationic group .

According to a specific embodiment o f the invention, the direct dyes comprise at least one quaternized cationic chromophore.

Mention may in particular be made, for the cationic azo dyes, o f those resulting from the cationic dyes described in the Kirk-Othmer Encyclopedia o f Chemical Technology, "Dyes, Azo", J. Wiley & Sons, updated on 19 April 2010.

Among the azo dyes that may be used according to the invention, mention may be made of the cationic azo dyes described in patent applications WO 95/ 1 5 144, WO 95/0 1772 and EP-714954.

According to a preferred embo diment of the invention, the direct dye(s) are chosen from cationic dyes known as "basic dyes" .

Mention may be made, among the azo dyes described in the Co lour Index International, 3rd edition, in particular o f the fo llowing compounds : Basic Red 22, Basic Red 76, Basic Yellow 57, Basic Brown 16 and Basic Brown 17.

Among the cationic quinone dyes, those mentioned in the abovementioned Co lour Index International are suitable and, among these, mention may be made, inter alia, of the fo llowing dyes : Basic Blue 22 and Basic Blue 99. Among the azine dyes which are suitable, mention may be made of those listed in the Colour Index International, for example of the following dyes: Basic Blue 17, Basic Red 2.

Among the cationic triarylmethane dyes which may be used according to the invention, mention may be made, in addition to those listed in the Colour Index, of the following dyes: Basic Green 1, Basic Violet 3, Basic Violet 14, Basic Blue 7 and Basic Blue 26.

Mention may also be made of the cationic dyes in the documents US 5 888 252, EP 1 133 975, WO 03/029 359, EP 860 636, WO 95/01772, WO 95/15144 and EP 714954. Mention may also be made of those listed in the encyclopaedia "The Chemistry of Synthetic Dyes" by K. Venkataraman, 1952, Academic Press, vol. 1 to 7, in the "Kirk- Othmer Encyclopedia of Chemical Technology", in the chapter "Dyes and Dye Intermediates", 1993, Wiley and Sons, and in various chapters of "Ullmann's Encyclopedia of Industrial Chemistry", 7th edition, Wiley and Sons.

Preferably, the cationic direct dyes are chosen from those resulting from dyes of azo and hydrazono type.

According to a specific embodiment, the direct dyes are cationic azo dyes, described in EP 850 636, FR 2 788 433, EP 920 856, WO 99/48465, FR 2 757385, EP 850637, EP 918 053, WO 97/44004, FR 2 570946, FR 2285 851, DE 2538363, FR 2 189006, FR 1 560664, FR 1 540423, FR 1 567219, FR 1 516 943, FR 1 221 122, DE 4220 388, DE 4 137 005, WO 01/66646, US 5 708 151, WO 95/01772, WO 515 144, GB 1 195 386, US 3 524 842, US 5 879 413, EP 1 062 940, EP 1 133 976, GB 738 585, DE 2 527 638, FR 2 275 462, GB 1974-27645, Acta Histochem. (1978), 61(1), 48-52; Tsitologiya (1968), 10(3), 403-5; Zh. Obshch. Khim., (1970), 40(1), 195-202; Ann. Chim. (Rome) (1975), 65(5-6), 305-14; J. Chinese Chem. Soc. (Taipei) (1998), 45(1), 209-211; Rev. Roum. Chim. (1988), 33(4), 377-83; Text. Res. J. (1984), 54(2), 105-7; Chim. Ind. (Milan) (1974), 56(9), 600-3; Khim. Tekhnol. (1979), 22(5), 548-53; Ger. Monatsh. Chem. (1975), 106(3), 643-8; MRL Bull. Res. Dev. (1992), 6(2), 21-7; Lihua Jianyan, Huaxue Fence (1993), 29(4), 233 -4; Dyes Pigm. ( 1992), 19( 1 ), 69-79; Dyes Pigm. ( 1 989), 1 1 (3), 163 -72.

Preferably, the cationic direct dye(s) comprise a quaternary ammonium group; more preferentially, the cationic charge is endocyclic.

These cationic radicals are, for example, a cationic radical :

- bearing an exocyclic (di/tri)(C 1 -C 8)alkylammonium charge, or

- bearing an endocyclic charge, such as comprising a cationic heteroaryl group chosen from: acridinium, benzimidazolium, benzobistriazolium, benzopyrazolium, benzopyridazinium, benzoquino lium, benzothiazolium, benzotriazo lium, benzoxazolium, bipyridinium, bis-tetrazolium, dihydrothiazolium, imidazopyridinium, imidazo lium, indolium, isoquino lium, naphthoimidazo lium, naphthoxazolium, naphthopyrazolium, oxadiazolium, oxazo lium, oxazo lopyridinium, oxonium, phenazinium, phenoxazolium, pyrazinium, pyrazolium, pyrazoyltriazo lium, pyridinium, pyridinoimidazolium, pyrrolium, pyrylium, quinolium, tetrazolium, thiadiazolium, thiazolium, thiazo lopyridinium, thiazoylimidazolium, thiopyrylium, triazo lium or xanthylium.

Mention may be made of the hydrazono cationic dyes of formulae (XII) and (XIII), and the azo cationic dyes o f formulae (XIV) and (XV) below :

Het+-C(Ra)=N-N(Rb)-Ar, Het+-N(Ra)-N=C(Rb)-Ar,

Q- Q-

(XII) (XIII)

Het+-N=N-Ar, Q- Ar+-N=N-Ar " , Q- (XIV) (XV)

in which formulae (XII) to (XV) :

• Het+ represents a cationic heteroaryl radical, preferentially bearing an endocyclic cationic charge, such as imidazo lium, indo lium or pyridinium, optionally substituted, preferentially with at least one (C 1 -C8) alkyl group such as methyl; • Ar+ represents an aryl radical, such as phenyl or naphthyl, bearing an exocyclic cationic charge, preferentially ammonium, particularly tri(C 1 -C8)alkylammonium such as trimethylammonium;

• Ar represents an aryl group, especially phenyl, which is optionally substituted, preferentially with one or more electron- donating groups such as i) optionally substituted (C 1 -C8)alkyl, ii) optionally substituted (C 1 -C8)alkoxy, iii) (di)(C 1 -C8)(alkyl)amino optionally substituted on the alkyl group(s) with a hydroxyl group , iv) aryl(C l -C 8)alkylamino, v) optionally substituted N-(C 1 -C8)alkyl-N- aryl(C 1 -C 8)alkylamino or alternatively Ar represents a julo lidine group;

• Ar" represents an optionally substituted (hetero)aryl group such as phenyl or pyrazolyl, which are optionally substituted, preferentially with one or more (C 1 -C 8)alkyl, hydroxyl, (di)(C l - C8)(alkyl)amino, (C 1 -C8)alkoxy or phenyl groups;

• Ra and Rb , which may be identical or different, representing a hydrogen atom or a (C l -C8)alkyl group, which is optionally substituted, preferentially with a hydroxyl group;

• or else the substituent Ra with a substituent of Het+ and/or Rb with a substituent o f Ar form, together with the atoms that bear them, a (hetero)cycloalkyl; in particular, Ra and Rb representing a hydrogen atom or a (C l -C4)alkyl group optionally substituted with a hydroxyl group;

• Q- represents an organic or mineral anionic counterion, such as a halide or an alkyl sulfate.

In particular, mention may be made of the azo and hydrazono direct dyes bearing an endocyclic cationic charge of formulae (XII) to (XV) as defined previously, more particularly the cationic direct dyes of formulae (XII) to (XV) bearing an endocyclic cationic charge, described in patent applications WO 95/ 15 144, WO 95/01 772 and EP 714 954; preferentially the fo llowing direct dyes :

in which formulae (XII-1) and (XIV-1):

- Rl represents a (Cl-C4)alkyl group such as methyl;

- R2 and R3, which may be identical or different, represent a hydrogen atom or a (Cl-C4)alkyl group such as methyl; and

- R4 represents a hydrogen atom or an electron-donating group such as optionally substituted (C 1 -C8)alkyl, optionally substituted (Cl-C8)alkoxy, or (di)(C 1 -C8)(alkyl)amino optionally substituted on the alkyl group(s) with a hydroxyl group; particularly, R4 is a hydrogen atom,

- Z represents a CH group or a nitrogen atom, preferentially

CH,

- Q ^" is an anionic counterion as defined above, in particular a halide, such as chloride, or an alkyl sulfate, such as methyl sulfate or mesityl.

Particularly, the dyes of formulae (XII-1) and (XIV-1) are chosen from Basic Red 51, Basic Yellow 87 and Basic Orange 31 or

with Q' being an anionic counterion as defined above, in particular a halide, such as chloride, or an alkyl sulfate, such as methyl sulfate or mesityl.

According to a specific embodiment o f the invention, the direct dyes are fluorescent, i. e. they comprise at least one fluorescent chromophore as defined above.

Mention may be made, as fluorescent dyes, o f the radicals resulting from the fo llowing dyes : acridines, acridones, benzanthrones, benzimidazoles, benzimidazolones, benzindo les, benzoxazoles, benzopyrans, benzothiazoles, coumarins, difluoro {2- [ (2H-pyrro 1-2 -y lidene-kN)met hy 1] - l H-pyrrolato-kN } borons

(BODIPY ^® ), diketopyrrolopyrroles, fluorindines, (poly)methines (in particular cyanines and styryls/hemicyanines), naphthalimides, naphthanilides, naphthylamines (such as dansyls), oxadiazoles, oxazines, perilones, perinones, perylenes, polyenes/carotenoids, squaranes, stilbenes and xanthenes .

Mention may also be made of the fluorescent dyes described in the documents EP 1 133 975 , WO 03/029 359, EP 860 636, WO 95/01772, WO 95/ 15 144 and EP 7 14 954 and those listed in the encyclopaedia "The Chemistry o f Synthetic Dyes" by K. Venkataraman, 1952, Academic Press, vo l. 1 to 7, in the "Kirk- Othmer Encyclopedia o f Chemical Technology" , in the chapter "Dyes and Dye Intermediates" , 1993 , Wiley and Sons, and in various chapters o f "Ullmann' s Encyclopedia o f Industrial Chemistry" , 7th edition, Wiley and Sons, and in "The Handbook — A Guide to Fluorescent Probes and Labeling Technologies" , 10th Ed. , Mo lecular Probes/Invitrogen - Oregon 2005 , circulated on the Internet or in the preceding printed editions.

According to a preferred variant of the invention, the fluorescent dye(s) are cationic and comprise at least one quaternary ammonium radical, such as those of formula (XV) below :

W+-[C(Rc)=C(Rd)]m'-Ar, Q- (XV) in which formula (XV) :

• W+ represents a cationic heterocyclic or heteroaryl group, particularly comprising a quaternary ammonium optionally substituted with one or more (C l -C8)alkyl groups optionally substituted especially with one or more hydroxyl groups;

• Ar representing an aryl group such as phenyl or naphthyl, optionally substituted preferentially with i) one or more halogen atoms such as chlorine or fluorine; ii) one or more (C l -C8)alkyl groups, preferably of C 1 -C4 such as methyl; iii) one or more hydroxyl groups; iv) one or more (C 1 -C8)alkoxy groups such as methoxy; v) one or more hydroxy(C 1 -C8)alkyl groups such as hydroxyethyl, vi) one or more amino groups or (di)(C 1 -C 8)alkylamino , preferably with the C 1 -C4 alkyl part optionally substituted with one or more hydroxyl groups, such as (di)hydroxyethylamino , vii) with one or more acylamino groups; viii) one or more heterocycloalkyl groups such as piperazinyl, piperidyl or 5 - or 6-membered heteroaryl such as pyrrolidinyl, pyridyl and imidazolinyl;

• m' represents an integer between 1 and 4 inclusive, and in particular m is 1 or 2; more preferentially 1 ;

• Rc and Rd, which may be identical or different, represent a hydrogen atom or an optionally substituted (C l -C8)alkyl group, preferentially o f C 1 -C4, or alternatively Rc contiguous with W+ and/or Rd contiguous with Ar form, with the atoms that bear them, a (hetero)cycloalkyl, particularly Rc is contiguous with W+ and form a (hetero)cycloalkyl such as cyclohexyl;

^• Q - is an organic or mineral anionic counterion as defined previously.

According to a particular embo diment of the invention, the direct dyes are natural.

Mention may be made especially o f lawsone, juglone, alizarin, purpurin, carminic acid, kermesic acid, purpurogallin, protocatechaldehyde, indigo, isatin, curcumin, spinulosin, apigenidin and orceins. Use may also be made of extracts or decoctions containing these natural dyes and in particular henna-based poultices or extracts .

Preferably, the direct dye(s) are chosen from ionic direct dyes , and in particular from anionic or cationic direct dyes . Even more preferentially, the direct dye(s) are chosen from the cationic direct dyes o f formulae (XII) to (XV) .

The direct dye(s) may represent from 0.001 % to 100% by weight, preferably from 0. 1 % to 50% by weight and better still from 0. 1 %) to 40%) by weight relative to the total weight o f the aqueous composition.

The direct dye(s) may advantageously represent from 0.001 %) to 1 00%) by weight, preferably from 0. 1 % to 50%> by weight and better still from 0. 1 % to 40% by weight relative to the total weight of the aqueous composition.

The aqueous composition may optionally contain one or more chemical oxidizing agents .

Preferably, the chemical oxidizing agent(s) are chosen from those described previously. Even more preferentially, the oxidizing agent is hydrogen peroxide.

This oxidizing agent advantageously consists o f hydrogen peroxide, in particular in aqueous solution (aqueous hydrogen peroxide so lution), the concentration o f which may range more particularly from 0. 1 % to 50% by weight, even more preferentially from 0.5 % to 20% by weight and better still from 1 % to 15 % by weight relative to the oxidizing composition.

Preferably, the aqueous composition also contains one or more alkaline agents, especially the alkaline agents as described previously.

The oxidizing aqueous composition may also comprise one or more thickeners .

According to one embodiment, the dyeing process according to the invention consists in using on the said fibres i) a substrate comprising on its surface one or more chemical oxidizing agents, preferably in so lid form, chosen from peroxygenated salts, such as persulfates, and ii) an aqueous composition comprising one or more direct dyes .

In accordance with this embodiment, the direct dye(s) are preferably chosen from anionic or cationic direct dyes and even more preferentially from the cationic direct dyes of formulae (XII) to (XV) .

According to one variant o f this embodiment, the dyeing process according to the invention consists in using on the said fibres i) a substrate comprising on its surface one or more chemical oxidizing agents, preferably in so lid form, chosen from peroxygenated salts, such as persulfates, and ii) an aqueous composition comprising (a) one or more direct dyes chosen from cationic direct dyes and even more preferentially from the cationic direct dyes o f formulae (XII) to (XV) , (b) one or more alkaline agents and (c) one or more chemical oxidizing agents, especially hydrogen peroxide.

According to another variant o f this embodiment, the dyeing process according to the invention consists in using on the said fibres i) a substrate comprising one or more chemical oxidizing agents, preferably in so lid form, partially covering the surface o f the said substrate, and ii) an aqueous composition comprising one or more anionic direct dyes .

In accordance with these embodiments, the keratin fibres thus treated are dyed with a lightening effect and a dyeing effect.

More precisely, according to one embodiment, the dyeing process according to the invention consists in placing the keratin fibres in contact with the substrate comprising on its surface one or more chemical oxidizing agents preferably in so lid form, and in then applying to the said fibres the aqueous composition containing one or more direct dyes .

According to one variant o f this embodiment, the dyeing process according to the invention consists in placing the keratin fibres in contact with the substrate comprising on its surface one or more chemical oxidizing agents preferably in so lid form, chosen from peroxygenated salts, such as persulfates, and in then applying to the said fibres the aqueous composition containing one or more direct dyes.

In accordance with this embodiment, the aqueous composition preferably comprises one or more direct dyes, one or more alkaline agents and one or more chemical oxidizing agents .

In particular, the keratin fibres are placed on the surface of the substrate bearing the oxidizing agent(s), i. e. at the place where the surface of the substrate is covered with the oxidizing agent(s), and the aqueous dye composition is then applied to the said fibres.

The keratin fibres are thus dyed with a lightening effect and a dyeing effect.

The aqueous composition may be applied using an applicator, in particular a brush, or by hand.

In accordance with this embodiment, after applying the composition, the locks o f hair thus treated may be protected with a paper to protect the other locks that have not been treated.

According to another embodiment, the dyeing process consists in applying an aqueous composition comprising one or more direct dyes to the keratin fibres and then in applying to the said fibres a substrate comprising on its surface one or more oxidizing agents .

In this embodiment, the order of application between the pretreated substrate and the aqueous composition is thus inverted relative to the preceding embodiment.

In this embodiment, the keratin fibres are especially placed on a support, for example the upper surface of a sheet of paper, the aqueous composition is applied to the said fibres and the substrate pretreated with one or more oxidizing agents is then applied to the said fibres. The oxidizing agents present on the surface o f the substrate are thus dissolved to lighten the keratin fibres, while the dyes dye the covered keratin fibres.

In accordance with this embodiment, the substrate pretreated with one or more oxidizing agents is applied to the keratin fibres treated with the aqueous composition so that the surface containing the oxidizing agent(s) is in contact with the fibres . The substrate pretreated with one or more oxidizing agents may be app lied to the keratin fibres for a time ranging from 5 to 60 minutes and preferably ranging from 15 to 60 minutes .

The aqueous composition containing the direct dye(s) may be applied to the keratin fibres for a time ranging from 5 to 60 minutes and preferably ranging from 15 to 60 minutes .

The substrate and the aqueous composition may be applied at room temperature (25 °C), optionally with raising o f the temperature, which may be up to 60°C .

After the treatment, the human keratin fibres are optionally rinsed with water, optionally washed with a shampoo and then rinsed with water, before being dried or left to dry.

Preferably, the substrate is pretreated with an oxidizing composition containing one or more oxidizing agents and one or more alkaline agents and the aqueous compo sition contains one or more direct dyes, one or more oxidizing agents and optionally one or more alkaline agents .

The process for preparing the substrate as described previously especially consists in depositing via a printing method an oxidizing composition containing one or more oxidizing agents onto the surface of a substrate.

In other words, the oxidizing composition is deposited onto the surface o f a substrate so as to obtain a substrate containing on its surface one or more chemical oxidizing agents .

Preferably, the oxidizing composition comprises one or more oxidizing agents in a content ranging from 0.01 % to 100% by weight, preferably from 1 % to 50% by weight and better still from 5 % to 40% by weight relative to the total weight of the said composition.

More preferentially, the oxidizing composition comprises one or more alkaline agents .

According to one embodiment, the process for preparing the substrate consists in depositing the composition containing the oxidizing agent(s) onto the surface o f a substrate covered with a deposit o f an adhesive composition. This adhesive layer may cover all or part of the substrate. In particular, the adhesive layer may represent a pattern.

According to one embodiment, the process for preparing the substrate as described previously consists in partially depositing onto the surface o f a substrate, via a printing method, an oxidizing composition containing one or more oxidizing agents .

In accordance with this embodiment, the oxidizing agent(s) are deposited in the form o f one or more patterns onto the surface o f a substrate.

In particular, the patterns may be squares, circles, ovals, ellipses or triangles, in the form o f filled patterns or of lines surrounding these patterns .

They may also be thick or thin, straight or curved lines, crossed lines, representing letters, stylized drawings or geometrical patterns .

They may also be dotted lines or spots .

The printing method serving to deposit the composition onto the surface o f a substrate may be a screen printing process, a flexography process, an o ffset process or a printing process using an inkj et printer or a laser printer.

The oxidizing composition intended to be printed onto the surface of the substrate may be liquid or in powder form, preferably in powder form.

According to a preferred embo diment, the oxidizing composition containing one or more oxidizing agents is printed onto the surface of the substrate by means o f a laser printer or an inkj et printer.

In accordance with this preferred embo diment, the oxidizing composition is in the form of a powder.

In accordance with one embodiment, the process for preparing the substrate consists in depositing onto the surface o f a substrate a composition containing the oxidizing agent(s) and then in heating the said surface to fix the powder. In particular, the oxidizing composition is printed by means o f a printing process using a laser printer or an inkj et printer onto the entire surface of the substrate, and the surface of the substrate is then selectively heated to produce one or more patterns on the said surface.

Preferably, the surface of the substrate is partially heated so as to create one or more patterns on the surface.

In accordance with another embodiment, the process for preparing the substrate consists in depositing the composition containing the oxidizing agent(s) onto the surface o f a substrate, and then in removing or rendering inefficient in certain places all or part of the oxidizing agents. In this way, this process can lead towards producing one or more patterns on the surface of the substrate.

The step consisting in partially removing the oxidizing agent(s) may be performed by means o f scraping, sponging, blowing, sucking or using an adhesive surface or a surface that is wetted at the places where it is desired to remove the oxidizing agent(s) .

The step consisting in rendering inefficient all or part of the oxidizing agents on the surface of the substrate may be performed by means o f a chemical transformation, for example a reduction, or by covering with a protective compound.

Moreover, the process for preparing the substrate may also comprise a step that consists in applying a film o f starch so as to reinforce the so lidity o f the substrate and improve the deposition o f the oxidation dye(s) onto the surface of the substrate .

The film o f starch may be thin, of the order of 2 g/m ² , or thick, of the order of 70 g/m ² .

The substrate thus pretreated in accordance with the preparation process according to the invention preferably dries within a period ranging from 5 minutes to 120 minutes, preferentially from 5 minutes to 90 minutes, more preferentially from 1 minute to 60 minutes and better still from 5 minutes to 60 minutes .

Advantageously, in this embo diment by printing, the substrate is an element in sheet form as described previously. The element in sheet form is pretreated on its surface with a composition comprising one or more chemical oxidizing agents such as those described previously.

The element in sheet form is thus entirely or partially covered on its surface with one or more chemical oxidizing agents .

In particular, the chemical oxidizing agent(s) in so lid form are preferably printed onto the element in sheet form.

The element in sheet form may be made from a nonwoven fibre material, especially a nonwoven made of cellulo se or a derivative thereo f. In particular, the element in sheet form may be a paper o f kraft type, which has the advantage o f printing well and o f leading to precise patterns. Specifically, the co loured patterns obtained on the keratin fibres do not run fo llowing the application of the aqueous composition.

Preferably, the element in sheet form may comprise at least one layer of at least one non-absorbing material.

The element in sheet form may be a sheet of plastic which especially has the advantage o f rendering the co louring power, which makes it possible to lead to patterns whose co louring is powerful. Furthermore, the sheet of plastic does not absorb the water present in the aqueous composition, which makes it possible to avoid creating dry areas under the keratin fibres during the application o f the said composition.

According to a first advantageous embodiment, the element in sheet form is a plastic sheet covered with a thin layer o f paper, in particular with a thickness o f less than 50 μιη and more preferentially less than 30 μιη, such as cigarette paper or a layer of paper that can be broken down in the presence of water, such as toilet paper, with a thin layer of hydrophilic material such as cellulo se or a hydrophilic silica.

According to this embodiment, the plastic sheet corresponds to the preferably non-absorbing material layer.

In accordance with this embodiment, the layer o f thin paper allows rapid drying, which prevents the co louring from running fo llowing the application o f the aqueous composition, which leads to sharp coloured patterns .

In the case where a support formed from a layer o f hydrophilic material is used:

the layer of hydrophilic material is typically from 5 to 200 μιη thick, which allows rapid drying and prevents the co louring from running fo llowing the application of the aqueous composition. This especially results in sharp coloured patterns.

According to a second advantageous embodiment, the element in sheet form is a microalveolar sheet, i. e. a sheet perforated with ho les that are spaced apart from each other by a plastic material. Thus, the oxidizing composition becomes housed in the ho les of the substrate, which will make it possible to better render the power of the direct dyes on the keratin fibres after application o f the aqueous composition.

The ho les are found at the surface o f the element in sheet form over a thickness ranging from 10% to 90% o f the thickness o f the sheet.

According to this embodiment, the plastic material corresponds to a non-absorbing material.

In accordance with this embodiment, the element in sheet form also has the advantage of printing well, o f better rendering the co louring leading especially to powerfully co loured patterns, of not excessively absorbing the water originating from the aqueous composition and o f minimizing the risks of running of the co louring, which results in precisely coloured patterns on the keratin fibres .

According to the first and second advantageous embodiments, the element in sheet form comprises at least one layer o f at least one non-absorbing material.

Preferably, the said layer of at least one non-absorbing material is a plastic layer.

The fo llowing examples serve to illustrate the invention without, however, exhibiting a limiting nature . EXAMPLE

Example 1 : 1 . Preparation of the substrate

A sheet of aluminium foil (30 cm x 10 cm) is used, the surface of which is entirely covered with a double-sided adhesive layer. The entire surface is sprinkled with a mixture o f peroxygenated salts/alkaline agent (mixture o f sodium persulfate ( 10) and potassium persulfate (40)/sodium metasilicate (2.5)), which is then shaken to remove the non-bound powder. The amount of powder deposited is about 5 mg/cm ² on the sheet of aluminium foil. 2. Preparation of the aqueous composition

An alkaline oxidizing aqueous composition is prepared from a weight-for-weight mixture, at the time of use, o f a composition so ld under the name Oxydant Riche INOA 20 vo lumes based on aqueous hydrogen peroxide so lution (6% hydrogen peroxide) and of an alkaline composition based on 5 % by weight o f aqueous ammonia containing 20% ammonia and 0.5 % by weight o f a cationic direct dye Basic Red 5 1 . 3. Procedure

A lo ck o f chestnut-brown hair is applied to the sheet and the lo ck is pasted on with the aqueous composition. After a leave-on time of 50 minutes, the lock is freed and rinsed.

It is found that the treated lock is correctly dyed, with a lightening effect and a dyeing effect.

Conversely, when all o f the compounds (peroxygenated salts , hydrogen peroxide, alkaline agents and direct dye) are mixed together in the same composition, a poorly dyed result is obtained on the lock of hair.

Example 2 :

1 . Preparation of the substrate

A sheet of aluminium foil (30 cm x 1 0 cm) is used, on which is placed a strip o f adhesive tape about 5 cm long. The foil is sprinkled with a mixture o f peroxygenated salts/alkaline agent (mixture o f sodium persulfate ( 10) and potassium persulfate (40)/sodium metasilicate (2.5)), and is then shaken to remove the non-bound powder.

The amount of powder deposited is about 5 mg/cm ² at the place where the adhesive tape is on the sheet of foil.

2. Preparation of the aqueous composition

An alkaline oxidizing aqueous composition is prepared from a weight-for-weight mixture, at the time of use, o f a composition so ld under the name Oxydant Riche INOA 20 vo lumes based on aqueous hydrogen peroxide so lution and o f an alkaline composition based on 5 % by weight of aqueous ammonia containing 20% ammonia and 0.5 % by weight of an anionic direct dye Acid Red 52.

3. Procedure

A lo ck o f chestnut-brown hair is applied to the sheet and the lo ck is pasted on with the aqueous composition. After a leave-on time of 50 minutes, the lock is freed and rinsed.

It is found that the treated lock is essentially bleached on its central part, i. e. in the area which bore the peroxygenated salts, and dyed red on the other two parts (facing the two areas which did not bear the peroxygenated salts) . Example 3 :

1 . Preparation of the substrate A sheet of aluminium foil (30 cm x 10 cm) is used, the surface of which is entirely covered with a double-sided adhesive layer. The entire surface is sprinkled with a mixture o f peroxygenated salts/alkaline agent (mixture o f sodium persulfate ( 10) and potassium persulfate (40)/sodium metasilicate (2.5)), which is then shaken to remove the non-bound powder. The amount of powder deposited is about 5 mg/cm ² on the sheet of aluminium foil.

2. Preparation of the aqueous composition An alkaline oxidizing aqueous composition is prepared from a weight-for-weight mixture, at the time of use, o f a composition so ld under the name Oxydant Riche INOA 1 0 vo lumes based on aqueous hydrogen peroxide so lution (3 % hydrogen peroxide) and of an alkaline composition based on 5 % by weight o f aqueous ammonia containing 20% ammonia and 0.5 % by weight of a nitrobenzene direct dye 4- amino-3 -nitrophenol sold by the company Dragon Chemicals .

3. Procedure A lo ck o f chestnut-brown hair is applied to the sheet and the lo ck is pasted on with the aqueous composition. After a leave-on time of 50 minutes, the lock is freed and rinsed.

The same procedure is carried out on nine locks o f chestnut- brown hair.

It is found that the treated lock is correctly dyed, with a lightening effect and a brown dyeing effect. Furthermore, the ten locks have the same color aspect. Conversely, when all o f the compounds (peroxygenated salts , hydrogen peroxide, alkaline agents and nitrobenzene direct dye) are mixed together in the same composition and then the resulted composition is applied on ten locks, variable dyeing results are achieved.

These results show an inhomogeneous and non-aesthetic dyeing.

Example 4

1 . Preparation of the substrate

The fo llowing mixture o f powder is prepared by mixing :

- 10 grams o f a mixture o f peroxygenated salts/alkaline agent (mixture o f sodium persulfate ( 10) and potassium persulfate (40)/sodium metasilicate (2.5)),

- 40 grams of salt (NaCl),

The obtained mixture powder is homogenizing and then sprinkled on a sheet of aluminium foil (30 cm x 10 cm) whose the surface is entirely covered with a double-sided adhesive layer.

The sheet is then shaken to remove the non-bound powder. The amount of powder deposited is about 5 mg/cm ² on the sheet o f aluminium foil.

2. Preparation of the aqueous composition

An alkaline oxidizing aqueous composition is prepared from a weight-for-weight mixture, at the time of use, o f a composition so ld under the name Oxydant Riche INOA 5 vo lumes based on aqueous hydrogen peroxide so lution ( 1 .5 % hydrogen peroxide) and o f an alkaline composition based on 5 % by weight of aqueous ammonia containing 20% ammonia and 0.5 % by weight of a triarylmethane direct dye CI 6730.

3. Procedure

A lo ck o f chestnut-brown hair is applied to the sheet and the lo ck is pasted on with the aqueous composition. After a leave-on time of 50 minutes, the lock is freed and rinsed. The same procedure is carried out on nine locks o f chestnut- brown hair.

It is found that the treated lock is correctly dyed, with a lightening effect and a purple-brown reflect. Furthermore, the ten lo cks have the same color aspect.

Conversely, when all o f the compounds (powder mixture, hydrogen peroxide, alkaline agents and direct dye) are mixed together in the same composition and then the resulted composition is applied on ten locks, variable dyeing results are achieved.

These results show an inhomogeneous and non-aesthetic dyeing.

Example 5 1 . Preparation of the substrate

The fo llowing powder mixture is prepared by mixing :

- 10 grams o f a mixture o f peroxygenated salts/alkaline agent (mixture o f sodium persulfate ( 10) and potassium persulfate

(40)/sodium metasilicate (2.5)),

- 40 grams of salt (NaCl), The obtained mixture powder is homogenizing and then sprinkled on a sheet of aluminium foil (30 cm x 10 cm) whose the surface is entirely covered with a double-sided adhesive layer.

The sheet is then shaken to remove the non-bound powder. The amount of powder deposited is about 5 mg/cm ² on the sheet o f aluminium foil.

2. Preparation of the aqueous composition

An alkaline oxidizing aqueous composition is prepared from a weight-for-weight mixture, at the time of use, o f a composition so ld under the name Oxydant Riche INOA 1 0 vo lumes based on aqueous hydrogen peroxide so lution (3 % hydrogen peroxide) and of an alkaline composition based on 5 % by weight o f aqueous ammonia containing 20% ammonia and 0.5 % by weight o f an anionic direct dye CI 1 91 0 so ld by the company Sensient.

3. Procedure

A lo ck o f chestnut-brown hair is applied to the sheet and the lo ck is pasted on with the aqueous composition. After a leave-on time of 50 minutes, the lock is freed and rinsed.

The same procedure is carried out on nine locks o f chestnut- brown hair.

It is found that the treated lock is correctly dyed, with a lightening effect and an orange reflect. Furthermore, the ten locks have the same color aspect.

Conversely, when all o f the compounds (powder mixture, hydrogen peroxide, alkaline agents and anionic direct dye) are mixed together in the same composition and then the resulted composition is applied on ten locks, variable dyeing results are achieved.

These results show an inhomogeneous and non-aesthetic dyeing. Example 6

1 . Preparation of the substrate

The fo llowing powder mixture is prepared by mixing :

- 10 grams o f a mixture o f peroxygenated salts/alkaline agent (mixture o f sodium persulfate ( 10) and potassium persulfate (40)/sodium metasilicate (2.5)),

- 40 grams of salt (NaCl),

The obtained mixture powder is homogenizing and then sprinkled on a sheet of aluminium foil (30 cm x 10 cm) whose the surface is entirely covered with a double-sided adhesive layer.

The sheet is then shaken to remove the non-bound powder. The amount of powder deposited is about 5 mg/cm ² on the sheet o f aluminium foil.

2. Preparation of the aqueous composition

An alkaline oxidizing aqueous composition is prepared from a weight-for-weight mixture, at the time of use, o f a composition so ld under the name Oxydant Riche INOA 5 vo lumes based on aqueous hydrogen peroxide so lution ( 1 .5 % hydrogen peroxide) and o f an alkaline composition based on 5 % by weight of aqueous ammonia containing 20% ammonia and 0.5 % by weight of an anthraquinone direct dye (hydroxyanthraquinoneaminopropyl methyl morpholinium methosulfate so ld by the company Chimex) . 3. Procedure

A lo ck o f chestnut-brown hair is applied to the sheet and the lo ck is pasted on with the aqueous composition. After a leave-on time of 50 minutes, the lock is freed and rinsed.

The same procedure is carried out on nine locks o f chestnut- brown hair.

It is found that the treated lock is correctly dyed, with a lightening effect and a purple-brown reflect. Furthermore, the ten lo cks have the same color aspect.

Conversely, when all o f the compounds (powder mixture, hydrogen peroxide, alkaline agents and anthraquinone direct dye) are mixed together in the same composition and then the resulted composition is applied on ten locks, variable dyeing results are achieved.

These results show an inhomogeneous and non-aesthetic dyeing.