WO2018046531A1

WO2018046531A1 - Process for treating keratin fibres, using ortho-dihydroxy-1,2-diphenylethylene derivatives, (hydrogen) carbonates and particular metal salts

Info

Publication number: WO2018046531A1
Application number: PCT/EP2017/072325
Authority: WO
Inventors: Gwénaelle JEGOU; Francis Pruche
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2016-09-06
Filing date: 2017-09-06
Publication date: 2018-03-15
Anticipated expiration: 2019-03-06

Abstract

Process for treating keratin fibres, using ortho-dihydroxy-1,2-diphenylethylene derivatives, (hydrogen) carbonates and particular metal salts The present invention relates to a process for treating keratin fibres, in particular human keratin fibres such as the hair, comprising the application, to said fibres, of one or more ortho-dihydroxy-1,2-diphenylethylene derivatives, of one or more manganese salts and/or one or more zinc salts, of one or more hydrogen carbonates and one or more additional divalent or trivalent metal salts other than the manganese salts and zinc salts.The present invention also relates to a multi-compartment device suitable for carrying out such a process.

Description

Process for treating keratin fibres, using ortho-dihydroxy- 1 ,2- diphenylethylene derivatives, (hydrogen) carbonates and particular metal salts The present invention relates to a process for treating keratin fibres, in particular human keratin fibres such as the hair, comprising the application o f one or more ortho-dihydroxy- 1 ,2-diphenylethylene derivatives in combination with one or more manganese and/or zinc derivatives, one or more (hydrogen) carbonates and one or more additional metal salts .

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 for this purpose.

The first type of dyeing is "permanent" or oxidation dyeing, which uses dye compositions containing oxidation dye precursors, generally referred to 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 colour modifiers. The variety of mo lecules used as oxidation bases and couplers allows a wide range of colours to be obtained.

Most of these permanent dyeing processes provide a good level of coverage o f grey hair. However, they require the presence o f an oxidizing agent in a strongly alkaline medium (pH generally of greater than 10) and these conditions are all the harsher, the greater the desired degree of coverage of the grey hairs on the head.

The second type of dyeing is " semi-permanent" dyeing or direct dyeing, which consists in applying direct dyes to the keratin fibres, the said dyes being co loured and co louring molecules that have an affinity for the fibres, and then leaving them to take, to allow the mo lecules to penetrate by diffusion to the interior of 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 . The direct dyes may also be natural dyes .

The co lourings resulting therefrom are particularly chromatic co lourings, but are, however, only temporary or semi-permanent since the nature of the interactions that bind the direct dyes to the keratin fibre and their desorption from the surface and/or the core of the fibre are responsible for their weak dyeing power and their poor persistence with respect to washing.

Given these drawbacks, consumers are increasingly seeking dyeing processes other than the conventional oxidation dyeing and direct dyeing processes. Consumers are especially seeking processes which use natural dyes, the use o f which is not aggressive for the keratin fibres, and especially which do not require the use of oxidizing agents, and which are more environmentally friendly. Consumers are in particular seeking dyeing methods which are well to lerated and which lead to as natural an appearance as possible.

In traditional Chinese medicine, which is in large part an oral tradition based on the ancestral use of natural products, the use o f plant extracts such as Black Shou Wu (hereinafter "BSW") is known, which is an extract of the roots of Radix Poligoni Multiflori and is used in particular to prevent hair loss and promote hair growth, as a conditioning agent and as an anti-dandruff agent.

Moreover, the use o f Poligonum Multiflorum extract has been mentioned for obtaining blonde co louring, especially in patent application DE 197 16 074.

There is a real need to develop novel processes for dyeing keratin fibres, making it possible to obtain co louring o f the hair while overcoming the abovementioned drawbacks. These processes must especially make it possible to cover grey hair. There is also a need to obtain gradual colouring of grey hair, to avoid an abrupt change in the user' s appearance. Gradual co lourings must have a natural effect. They must also make it possible to uniformly cover the head of hair.

These processes must also be easy to apply.

The Applicant has discovered, surprisingly, that the use o f one or more ortho-dihydroxy- 1 ,2-diphenylethylene derivatives with one or more metal salts in a medium comprising salts or oxides o f manganese and/or zinc, and (hydrogen) carbonates, made it possible to achieve the aims set out above.

Therefore, a subj ect of the present invention is a process for treating keratin fibres, in particular human keratin fibres such as the hair, comprising the application, to said fibres, of one or more ortho- dihydroxy- 1 ,2-diphenylethylene derivatives, of one or more manganese and/or zinc derivatives chosen from manganese salts or oxides and zinc salts or oxides, of one or more (hydrogen) carbonates and of one or more additional divalent or trivalent metal salts other than the manganese salts and zinc salts .

The process of the invention advantageously comprises :

a) application, to the fibres, of a composition (A) comprising the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) and the manganese and/or zinc derivative(s),

b) application, to the fibres, of a composition (B) comprising the (hydrogen) carbonate(s), and

c) application, to the fibres, of the additional divalent or trivalent metal salt(s) other than the manganese salts and zinc salts, these additional metal salts being present in the composition (A) and/or in the composition (B) and/or in an additional separate composition (C) .

The present invention also relates to a multi-compartment device containing : in a first compartment, a composition (A) comprising one or more ortho-dihydroxy- 1 ,2-diphenylethylene derivatives and one or more manganese and/or zinc derivatives; in a second compartment, a composition (B) comprising one or more (hydrogen) carbonates; one or more additional divalent or trivalent metal salts other than the manganese salts and zinc salts being present in the composition (A) and/or in the composition (B) and/or in an additional separate composition (C) present in a third compartment.

The treatment process according to the invention is a dyeing process which makes it possible to obtain a (re)pigmentation of the keratin fibres, which is both gradual and visible from the first application.

Unlike conventional dyeing processes, the process of the invention makes it possible to produce a real pigmentation or a re- pigmentation of the keratin fibres by returning to the original co lour or by providing shades thereto, or else by changing the co lour. In the case o f grey hair, the process makes it possible to gradually re- pigment the hair, depending on the number o f applications. It also makes it possible to prevent or delay the appearance of grey hair.

The process o f the invention differs from oxidation dyeing processes because it does not employ the condensation of dye precursors in the presence o f an oxidizing agent. It also does not correspond to a direct dyeing process because it does not emplo y co loured mo lecules. In particular, the ortho-dihydroxy- 1 ,2- diphenylethylene derivatives used in the present invention are not co loured mo lecules, unlike direct dyes .

The process according to the invention may be repeated, which makes it possible to gradually obtain a natural dark, or even black, co louring effect. The process o f the invention especially makes it possible to obtain an excellent level o f dark pigmentation and good coverage of grey hair from three applications. The repeated applications may take place one after the other or be separated by several hours or even several days .

The process thus makes it possible to obtain good colouring intensity, especially good coverage of grey hair over the whole head of hair, and also good colour homogeneity along the keratin fibres .

Finally, the co lourings obtained in this way are not aggressive and are well tolerated by the keratin fibres. The process according to the invention does not damage the keratin fibres and provides them with a good level o f conditioning, especially in terms o f manageability, softness, smoothness and disentangling.

Another subj ect of the present invention is a pigment obtained by the reaction of one or more ortho-dihydroxy- 1 ,2-diphenylethylene derivatives, of one or more manganese and/or zinc derivatives chosen from manganese salts or oxides and zinc salts or oxides, of one or more hydroxides and/or (hydrogen) carbonates, and of one or more additional metal salts other than the manganese salts and zinc salts.

The present invention also relates to a dyeing composition comprising said pigment.

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.

In that which will follow, and unless otherwise indicated, the limits o f a range o f values are included within this range, especially in the expressions "between ... and" and "ranging from ... to

Moreover, the expressions "at least one" and "at least" used in the present description are equivalent to the expressions "one or more" and "greater than or equal to", respectively.

The term "substituted" or "optionally substituted" is intended to mean conventional substituents o f the chemical radicals in question, such as alkyl, amino, aminoalkyl, hydroxyl, hydroxyalkyl, halogenated substituents, etc. Ortho-dihydroxy- 1 ,2-diphenylethylene derivatives

The present invention employs one or more ortho-dihydroxy- 1 ,2-diphenylethylene derivatives, especially present in the composition (A) .

"Ortho-dihydroxy- 1 ,2-diphenylethylene derivatives" denotes compounds comprising at least one ortho-dihydroxy- 1 ,2- diphenylethylene group in their chemical structure. They preferably comprise one ortho-dihydroxy- 1 ,2-diphenylethylene group or two ortho-dihydroxy- 1 ,2-diphenylethylene groups (especially in the case of ortho-dihydroxy- 1 ,2-diphenylethylene dimers) in their structure. These compounds may be compounds, the hydroxyl groups of which are protected, such as, for example, the corresponding glycosylated derivatives.

The ortho-dihydroxy-l,2-diphenylethylene derivative(s) used according to the present invention may be of natural or synthetic origin.

These compounds are preferentially chosen from:

glycosylated derivatives, such as 2,3,5,4'-tetrahydroxystilbene 2- Ο-β-D-glucoside; trans-3'- -glucopyranosyl-4,5'-dihydroxy-3- methoxystilbene; trans-3'- -glucopyranosyl-3,4,5'-trihydroxystilbene; and piceatannol 3-glucoside;

non-glycosylated derivatives, such as trans-3-methoxy-3',4,5'- trihydroxystilbene; piceatannol (trans-3,3',4,5'-tetrahydroxystilbene); 5-[(lE)-2-phenylethenyl]-l,2,3-benzenetriol; 4-[(lZ)-2-(3,5- dihydroxyphenyl)ethenyl]-l,2-benzenediol; 5-[(lE)-2-(4- hydroxyphenyl)ethenyl]-l ,2,3-benzenetriol; 5-[(lE)-2-(3,4- dihydroxyphenyl)ethenyl]-l ,2,3-benzenetriol; 4-[(lE)-2-(2,4- dihydroxyphenyl)ethenyl]-l ,2-benzenediol; α-[[(2Ε)-3-[2-[(1Ε)-2-(3,4- dihydroxyphenyl)ethenyl]-3 ,4-dihydroxyphenyl]- 1 -oxo-2-propen- 1 - yl]oxy]-3,4-dihydroxy-benzenepropanoic acid; ethyl 2-[(lE)-2-(3,4- dihydroxyphenyl)ethenyl]-6-hydroxybenzoate and 4-[(lE)-2-(3,5- dimethoxyphenyl)ethenyl]- 1 ,2-benzenediol; and

the optical and/or geometric isomers, the salts and/or solvates and the mixtures of such derivatives.

The ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) of use according to the present invention may also be in dimer form, such as those described in the Journal of Chemical Research (2004), (5), 339- 340, such as andalasin B, extracted from the roots of Morus macroura.

Mention may also be made of condensed tannins of ortho- dihydroxy-l,2-diphenylethylene, such as those described in Tetrahedron Letters (1983), 24(38), 4147-50.

More preferentially, the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) are chosen from glycosylated derivatives, and better still, the composition (A) comprises 2,3 ,5 ,4'-tetrahydroxystilbene 2-Ο-β-ϋ- glucoside.

According to a particularly preferred embodiment of the present invention, the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) are o f natural origin. In this embodiment, the composition (A) comprises one or more extracts of plants which may be chosen, for example, from Polygonum multiflorum, Radix Poligoni Multiflori, Fallopia multiflora, Smilax china, Morus australis Poir, Cistanche tubulosa, Millettia erythrocalyx, Artocarpus lakoocha, Cissus assamica, Veratrum maackii, Vitis vinifera, Vitis labrusca, Smilax stans, Picea abies, and Guibourtia coleosperma, said extracts containing the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) .

The ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) used in the present invention may be extracted from the plants mentioned above, according, for example, to the protocol described in patent application CN 1034055 16.

When the composition (A) is liquid, the total amount of the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives present in the composition (A) preferably ranges from 0.00 1 % to 15 % by weight and more preferentially from 0.01 % to 10% by weight relative to the total weight of the composition (A) .

When these compounds are used in the form o f plant extract, a content of extract ranging from 0. 1 % to 50% by weight and preferably from 0.5 % to 30% by weight relative to the total weight of the composition (A) is typically used.

When the composition (A) is so lid, the total amount of the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives present in the composition (A) preferably ranges from 1 % to 99% by weight and more preferentially from 10% to 60% by weight relative to the total weight of the composition (A) .

According to a particularly preferred embodiment, the process according to the invention does not employ oxidation dyes or direct dyes other than the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives and the (poly)phenols as described below. Manganese and/or zinc derivatives

The process o f the invention also comprises the application o f one or more manganese (Mn) and/or zinc (Zn) derivatives, chosen from the salts or the oxides .

These manganese and/or zinc derivative(s) are preferably contained in the composition (A) .

For the purposes o f the present invention, "salts" are intended to mean actual salts in the ionized form. These salts may be so lvated, in particular hydrated.

The derivatives are preferably salts .

Particularly, the derivatives o f the invention are in oxidation state II, such as Mn(II) and Zn(II) .

The manganese and/or zinc salt(s) are advantageously chosen from chlorides, fluorides, iodides, bromides, sulfates, phosphates, nitrates, perchlorates, carbonates, carboxylates, and mixtures thereof.

The carboxylates o f use in the invention also include carboxylic acid salts comprising one or more hydroxyl radicals such as gluconates .

By way o f example o f carboxylates, mention may be made, for example, o f acetate, tartrate, lysinate, glutamate, lactate, glycinate, aspartate, stearate, acetylacetate.

The manganese and zinc derivatives can be introduced in the so lid form into the compositions or else can be introduced in the form of aqueous so lution, such as a natural, mineral or spring water which is rich in these ions or else from seawater (Dead Sea water, especially). They can also originate from mineral compounds, such as earths, ochres, such as clays (for example green clay), or even from plant extracts containing them (cf. , for example, the document FR 2 8 14 943) .

Among the manganese salts, preference is given to manganese chloride, manganese carbonate, manganese difluoride, manganese acetate tetrahydrate, manganese lactate trihydrate, manganese phosphate, manganese iodide, manganese nitrate trihydrate, manganese bromide, manganese perchlorate tetrahydrate, manganese sulfate monohydrate, manganese gluconate and mixtures thereof.

Among the zinc salts, preference is given to zinc sulfate, zinc gluconate, zinc chloride, zinc lactate, zinc acetate, zinc glycinate, zinc aspartate and mixtures thereof.

Preferably, the process of the invention employs one or more manganese salts, in particular Mn(II) metal salts.

Even more preferentially, the manganese salt(s) are chosen from manganese carboxylates, especially manganese gluconate, and manganese halides, such as manganese chloride, and mixtures thereof.

Better still, the manganese salt(s) are chosen from manganese chloride, manganese gluconate and mixtures thereof.

When the composition (A) comprises one or more manganese derivatives, the total concentration of said derivative(s) in the composition (A) preferably ranges from 10^"3 to 10^{" 1} mmo l. l^{" 1} , and more preferentially from 10^"2 to 1 0^{" 1} mmo l. l^{" 1} .

When the composition (A) comprises one or more zinc derivatives, the total concentration of said derivative(s) in the composition (A) ranges from 5. 10^"2 to 10 mmo l. l^{" 1} , and more preferentially from 5. 10^{" 1} to 1 mmol. l^{" 1} .

The amounts above are expressed relative to a composition (A) in liquid form.

The (hydrogen) carbonates

The (hydrogen) carbonate(s) used in the process o f the invention are especially chosen from the compounds o f the fo llowing formulae :

R'⁺, HCO3 ^" with R' representing a hydrogen atom, an alkali metal, an ammonium group Rⁿ4N⁺- or a phosphonium group Rⁿ4P⁺- in which the groups R", which are identical or different, represent a hydrogen atom, an optionally substituted (C i -C₆)alkyl group, such as hydroxyethyl; when R' represents a hydrogen atom, the hydrogen carbonate is then referred to as dihydrogen carbonate (CO2 , H₂0); and Met'²⁺ (HC03^~)2 , with Met ' representing an alkaline earth metal.

More particularly, the (hydrogen) carbonate(s) are chosen from alkali metal hydrogen carbonates, alkaline earth metal hydrogen carbonates, ammonium hydrogen carbonates and the mixtures thereof; and more preferentially from alkali metal hydrogen carbonates, alkaline earth metal hydrogen carbonates and mixtures thereof.

Better still, the hydrogen carbonates are chosen from sodium, potassium, magnesium and calcium hydrogen carbonates and the mixtures thereo f, and in particular sodium hydrogen carbonate and potassium hydrogen carbonate . Even more preferentially, the hydrogen carbonate used in the process o f the invention is sodium hydrogen carbonate.

These (hydrogen) carbonates may originate from a natural water, for example spring water from the Vichy basin or from La- Roche Posay or Badoit water (cf. for example, patent document FR 2 8 14 943) . Mention may particularly be made o f sodium carbonate Na₂CC" 3 , and sodium hydrogen carbonate or sodium bicarbonate NaHCOs .

These hydrogen carbonates may also be generated in situ by any process making it possible to generate an HC O3 ^" salt.

The composition (B) may contain a total amount of the (hydrogen) carbonate(s) which preferably ranges from 0. 1 % to 15 % by weight and more preferentially from 0.5 % to 1 0% by weight relative to the total weight of the composition (B) .

According to a preferred embodiment, the total mo lar concentration o f (hydrogen) carbonates is greater than the total mo lar concentration o f manganese salts and of zinc salts applied to the keratin fibres. The metal salts other than the manganese and zinc salts

The process according to the present invention also emp loys one or more additional divalent or trivalent metal salt(s) other than the manganese salts and zinc salts defined above. For the purposes o f the present invention, "metal salt" is intended to mean actual salts, that is to say in ionized form, o f the metals o f co lumns 3 to 14 of the periodic table o f the elements, other than manganese and zinc.

Among these additional metal salts, mention may especially be made o f hydroxides, halides, sulfates, phosphates, nitrates and carboxylates .

The additional metal salt(s) are preferably chosen from iron(II) salts and iron(III) salts .

More preferentially, the additional metal salt(s) are chosen from iron sulfate, iron fumarate, iron gluconate, iron acetylacetonate, iron oxalate, mixed salts, such as Mohr' s salt, and the mixtures thereo f; and better still, iron sulfate.

According to a first preferred embodiment, the additional metal salt(s) are present in the composition (A) .

According to a second preferred embodiment, the additional metal salt(s) are present in a composition (C) separate from the compositions (A) and (B) .

It is also possible to combine these two embodiments, and to use the additional metal salt(s) both in the composition (A) and in a separate composition (C) .

The total amount of the additional metal salt(s) preferably ranges from 0.001 % to 5 % by weight and more preferentially from 0.01 % to 4% by weight relative to the total weight of the composition containing same.

Deglycosylation

In the case in which one or more glycosylated derivatives o f ortho-dihydroxy- l ,2-diphenylethylene are used in the process o f the invention, the process also comprises the use of an enzyme of β glucosidase type, in order to promote deglycosylation and therefore to optimize the co louring obtained. Use may also be made of any other means known for deglyco sylating, such as those described, for example, in Kinetics and mechanism o f 2,3 ,5 ,4'-tetrahydroxystilbene- 2-0-P-d-glycoside (THSG) degradation in aqueous solutions, J. Pharm. Biomed. Anal. 201 1 Apr 28 ;55 ( 1 ) :21 1 -5. Epub 2010 Dec 3 1 .

It is possible to add the enzyme extemporaneously into the composition (A) comprising the glycosylated dihydroxy- 1 ,2- diphenylethylene, immediately before applying this composition to the fibres.

It is also possible to add the enzyme extemporaneously into the composition (A) comprising the glyco sylated dihydroxy- 1 ,2- diphenylethylene, to add, if required, an aqueous so lution at pH 5 to 9 if the initial composition did not contain water, to maintain this new composition as is from 10 min to 2 hours, preferably from 15 min to 1 hour before applying to the fibres, said enzyme possibly being eliminated from this composition just before applying to the fibres, by any means known to those skilled in the art.

Preferentially, glucosidases of natural origin are used, such as almond beta glucosidases, such as, in particular, sweet almond glucosidase EC 3.2. 1 .

It is possible to use, for examp le, the almond β-glucosidase so ld by Aldrich under the name 49290 SIGMA β-Glucosidase from almonds lyophilized, powder, ^ 6 U/mg. This composition may be applied in solution at 1 mg/ml for 30 min to 1 hour.

Preferentially, the composition containing an enzyme o f β- glucosidase type is applied at a temperature of less than 55 °C and more preferentially from 30 to 40°C . The pH of this composition may range from 5 to 9.

Surfactants

The compositions o f use for the invention may optionally comprise one or more surfactants .

The surfactant(s) of use are preferably chosen from nonionic surfactants, anionic surfactants and amphoteric or zwitterionic surfactants .

The total amount of surfactant(s) present in the compositions according to the invention may range from 0. 1 % to 30% by weight, and preferably from 0.5 % to 20% by weight relative to the total weight of each composition containing same.

The surfactant(s) are preferably present in the composition (B) . The polyphenols other than the ortho-dihydroxy- 1 ,2- diphenylethylene derivatives

The process o f the invention may comprise the application, to the keratin fibres, of one or more additional phenol(s) other than the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives.

The additional pheno l(s) are preferably contained in the composition (A) .

These additional polyphenols are preferably chosen from ortho- diphenols, that is to say compounds comprising one or more aromatic rings, preferably benzene rings, comprising at least two hydroxyl groups (OH) borne by two adj acent carbon atoms of the same aromatic ring. The ortho-dipheno l(s) of use in the invention are preferably not auto-oxidizable derivatives, especially auto-oxidizable derivatives with an indo le unit. More particularly, they are not 5 ,6- dihydroxyindole.

The aromatic ring may more particularly be a fused aryl or fused heteroaromatic ring, i. e. optionally comprising one or more heteroatoms, such as benzene, naphthalene, tetrahydronaphthalene, indane, indene, anthracene, phenanthrene, isoindo le, indo line, isoindo line, benzo furan, dihydrobenzo furan, chroman, isochroman, chromene, isochromene, quino line, tetrahydroquinoline and isoquino line, said aromatic ring comprising at least two hydroxyl groups borne by two adjacent carbon atoms of the aromatic ring. Preferentially, the aromatic ring of the ortho-dipheno l derivatives according to the invention is a benzene ring.

"Fused ring" is intended to mean that at least two saturated or unsaturated and heterocyclic or non-heterocyclic rings have a common bond, that is to say that at least one ring is placed side-by-side with another ring. The additional ortho-dipheno ls may or may not be salified. They may also be in the aglycone form (without bonded sugar) or in the form of glycosylated compounds .

According to a particularly preferred embodiment, the composition (A) comprises one or more ortho-dipheno l(s) o f formula (I) below, or an oligomer thereof, in salified or non-salified form:

formula (I), in which the substituents Ri to R₄, which are identical or different, represent:

a hydrogen atom,

a halogen atom,

a hydroxyl radical,

- a carboxyl radical,

an alkyl carboxylate or alkoxycarbonyl radical,

an optionally substituted amino radical,

an optionally substituted and linear or branched alkyl radical, an optionally substituted and linear or branched alkenyl radical, - an optionally substituted cycloalkyl radical,

an alkoxy radical,

an alkoxyalkyl radical,

an alkoxyaryl radical, it being possible for the aryl group to be optionally substituted,

- an aryl radical,

a substituted aryl radical,

a saturated or unsaturated heterocyclic radical carrying or not carrying a cationic or anionic charge, optionally substituted and/or optionally fused with an aromatic ring, preferably a benzene ring, said aromatic ring being optionally substituted, in particular with one or more hydroxyl or glycosyloxy groups, a radical containing one or more silicon atoms,

or two of the substituents borne by two adj acent carbon atoms (namely Ri and R₂, R₂ and R₃ or R₃ and R₄) form, together with the carbon atoms bearing them, a saturated or unsaturated and aromatic or non- aromatic ring, optionally containing one or more heteroatoms and optionally fused with one or more saturated or unsaturated rings optionally containing one or more heteroatoms .

Preferably, the additional ortho-diphenol derivatives o f formula (I) are chosen from those in which two adjacent substituents Ri - R₂, R₂ - R₃ or R₃ - R₄ cannot form, with the carbon atoms which bear them, a cyclic radical, in particular a pyrrolyl radical. More particularly, R₂ and R₃ cannot form a pyrro lyl radical fused to the benzene ring bearing the two hydroxyls .

For the purposes o f the present invention and unless otherwise indicated:

The saturated or unsaturated and optionally fused rings may also be optionally substituted.

The alkyl radicals are saturated and linear or branched hydrocarbon radicals, generally C i -C₂o hydrocarbon radicals, particularly C i -C i o hydrocarbon radicals, preferably C i -C₆ alkyl radicals such as methyl, ethyl, propyl, butyl, pentyl and hexyl. - The alkenyl radicals are unsaturated and linear or branched C₂-C₂o hydrocarbon radicals, preferably comprising at least one double bond, such as ethylene, propylene, butylene, pentylene, 2- methylpropylene and decylene.

The aryl radicals are monocyclic or fused or non-fused polycyclic carbon-based radicals, preferentially comprising from 6 to 30 carbon atoms, at least one ring o f which is aromatic; the choice is preferentially made, from the aryl radical, o f a phenyl, biphenyl, naphthyl, indenyl, anthracenyl and tetrahydronaphthyl. The alkoxy radicals are alkyloxy radicals with alkyl as defined above, preferably C i -C i o alkyloxy radicals, such as methoxy, ethoxy, propoxy and butoxy.

The alkoxyalkyl radicals are preferably (C 1 -C20) alkoxy (C 1 -C20) alkyl radicals, such as methoxymethyl, ethoxymethyl, methoxyethyl, ethoxyethyl, etc.

The cycloalkyl radicals are generally C 4 - C 8 cycloalkyl radicals, preferably the cyclopentyl and cyclohexyl radicals. The cycloalkyl radicals can be substituted cyclo alkyl radicals, in particular substituted with alkyl, alkoxy, carboxylic acid, hydroxyl, amine and ketone groups .

The additional ortho-dipheno ls o f use in the process o f the invention may be natural or synthetic. The natural ortho-dipheno ls include the compounds which may be present in nature and which are reproduced by chemical (semi)synthesis.

According to a particular embodiment of the invention, the process comprises the application o f one or more additional synthetic ortho-dipheno l(s) that do not exist in nature.

According to another preferred embodiment of the invention, the additional ortho-diphenols are natural ortho-dipheno ls.

More particularly, the additional natural ortho-dipheno ls of use in the process of the invention are chosen from:

- flavano ls, such as catechin and epicatechin gallate,

- flavono ls, such as quercetin,

- anthocyanidins, such as cyanidin, delphinidin, petunidin or pelargonidin,

- anthocyanins or anthocyans such as delphinidin 3 -0- glucoside, also referred to as myrtillin,

ortho-hydroxybenzoates, for example gallic acid derivatives, and in particular gallates, for example propylgallate,

- flavones, such as luteolin,

- 3 ,4-dihydroxyphenylalanine and the derivatives thereof, such as L-3 ,4-dihydroxyphenylalanine methyl ester hydrochloride,

- 2,3 -dihydroxyphenylalanine and the derivatives thereof, - 4,5 -dihydroxyphenylalanine and the derivatives thereof,

- dihydroxycinnamates, such as caffeic acid and chlorogenic acid,

- ortho-polyhydroxycoumarins,

- ortho-polyhydroxyisocoumarins,

- ortho-polyhydroxycoumarones,

- ortho-polyhydroxyisocoumarones,

- ortho-polyhydroxychalcones,

- ortho-polyhydroxychromones,

- quinones,

- hydroxyxanthones,

- 1 ,2-dihydroxybenzene and the derivatives thereof,

- 1 ,2,4-trihydroxybenzene and the derivatives thereof,

- 1 ,2,3 -trihydroxybenzene and the derivatives thereof,

- 2,4,5 -trihydroxyto luene and the derivatives thereof,

- proanthocyanidins and especially the proanthocyanidins A l , A2, B l , B2, B3 and C I ,

- proanthocyanins,

- tannic acid,

- ellagic acid,

- and mixtures of the preceding compounds,

and more particularly from catechin, quercetin, brazilin (CAS 474-07-7), haematein, haematoxylin, chlorogenic, caffeic and gallic acids, catechol, L DOPA, pelargonidin, cyanidin, (-)-epicatechin, (-)- epigallo catechin, (-)-epigallocatechin 3 -gallate (EGCG), (+)-catechin, isoquercetin, pomiferin, esculetin, 6,7-dihydroxy-3 -(3 -hydroxy-2,4- dimethoxyphenyl)coumarin, santalin AC, mangiferin, butein, maritimetin, sulfuretin, robtein, betanidin, pericampylinone A. , theaflavin, proanthocyanidin A2, proanthocyanidin B2, proanthocyanidin C I , procyanidins DP 4-8 , tannic acid, purpurogallin, 5 ,6-dihydroxy-2-methyl- l ,4-naphthoquinone, alizarin, wedelo lactone, variegatic acid, gomphidic acid, xerocomic acid, carnoso l, and the natural extracts containing same. Preferentially, the additional ortho-diphenol(s) according to the invention are chosen from flavano ls, flavono ls, ortho- hydroxybenzoates, iso flavones and neoflavones .

According to one embodiment, the natural ortho-dipheno ls are derived from, or are introduced in the form o f, extracts of animals, bacteria, fungi, algae, plants and fruits, used in their entirety or partially. In particular regarding plants, the extracts are derived from fruits, including citrus fruits, from vegetables, from trees, from shrubs and lichen. Use may also be made of mixtures of these extracts rich in ortho-dipheno ls as defined above.

Preferably, the additional ortho-dipheno l(s) are natural ortho- diphenols derived from extracts of plants or plant parts. These extracts of plants or plant parts may be used directly in the process o f the invention.

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

Mention may be made, among the extracts of plants, of extracts of rose or tea leaves .

Mention may be made, among the extracts of fruit, o f extracts of apple, extracts of grape (in particular of grape seed) or extracts of cocoa beans and/or pods .

Mention may be made, among the extracts of vegetables, o f extracts of potato or of onion peel.

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

Use may also be made of mixtures of plant extracts .

According to a particular embodiment of the invention, the ortho-dipheno l(s) are natural extracts rich in ortho-diphenols. According to a preferred embodiment, the additional ortho-dipheno l derivative(s) are so lely contained in natural extracts .

Preferentially, the polyphenol(s) used in the process according to the invention are chosen from catechin, quercetin, haematein, haematoxylin, brasilin, gallic acid, and natural extracts containing same, chosen especially from grape marc, pine bark, green tea, onion, cocoa bean, logwood, redwood and gall nut. The extract used is preferably logwood.

More preferentially still, the additional po lypheno l(s) are chosen from catechin, quercetin, gallic acid and haematoxylin.

The natural extracts containing the additional po lypheno ls according to the invention may be in the form of powders or liquids. Preferably, the extracts containing the additional po lypheno ls according to the invention are in the form of powders .

According to the invention, the synthetic or natural polypheno l(s) and/or the natural extract(s) containing same preferably represent(s) from 0.001 % to 20% by weight of the total weight of the composition containing same, preferably the composition (A) .

As regards the pure ortho-dipheno ls, the content in the composition(s) containing same is preferably between 0.001 %) and 5 % by weight of each of these compositions .

According to a particularly preferred embodiment, the process according to the invention does not employ oxidation dyes or direct dyes other than the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives and the additional polyphenols described above.

The compositions

The compositions used in the present invention may be in any form which is compatible with an application to keratin fibres, and especially the hair.

In particular, the compositions (A) and (B) and, where appropriate, (C), of use in the invention may be in the form o f liquid or powder compositions. According to a preferred embodiment, the compositions (A) and (B) and, where appropriate, (C), are in the form of liquid compositions such as solutions .

They may be aqueous solutions, in particular aqueous-alcoho lic so lutions. They generally comprise water or a mixture of water and o f one or more so lvents, for example chosen from the lower C i to C₄ alcoho ls, such as ethano l, isopropanol, tert-butano l or n-butano l; polyo ls such as glycerol, propylene glycol and polyethylene glyco ls, and the mixtures thereof.

When they are present, the total amount of the so lvent(s) preferably ranges from 0.01 % to 50% by weight and more preferentially from 0.05 % to 30% by weight relative to the weight o f each composition containing same.

When the composition which contains the metal salt is in the form o f a so lution, the latter must not flo cculate. Those skilled in the art will choose the suitable pH to prevent flocculation o f the composition, as a function o f the metal salt.

When it is aqueous, the composition (A) has an acid pH, preferably ranging from 3 to 7. When it is aqueous, composition (B) has a rather basic pH, preferably between 7. 1 and 9.5. When it is aqueous, the composition (C) has a rather acid pH, ranging from 2 to 7, preferably from 3 to 4.

The additives

The compositions of use in the invention may comprise one or more additives, among which mention may be made o f cationic, anionic, nonionic and amphoteric polymers or the mixtures thereo f, thickeners, anti-dandruff agents, antiseborrheic agents, agents for preventing hair lo ss and/or promoting hair regrowth, vitamins and provitamins including pantheno l, sunscreens, sequestrants, plasticizers, so lubilizers, acidifying agents, opacifiers or nacreous agents, hydroxy acids, fragrances, preserving agents, or fillers, preferentially o f natural origin. As fillers, mention may be made o f pigments such as iron oxides derived from ochres, carbon black, chlorophyll or polymerized anthocyanins .

The above additives may be present in an amount, for each o f them, o f between 0 and 20% by weight relative to the total weight of each composition containing same, for a liquid composition.

The above additives may be present in an amount, for each o f them, o f between 0 and 80% by weight relative to the total weight of each composition containing same, for a solid composition. The process

When the process according to the present invention is carried out starting with the compositions (A), (B) and where appropriate (C), the compositions (A) and (B), and also the composition (C) when it is present, are applied to dry or wet keratin fibres and preferably to wet keratin fibres.

According to a preferred embodiment, the additional metal salt(s) as defined above are present in a composition (C) separate from the compositions (A) and (B) and the three compositions (A), (B) and (C) are applied successively to the keratin fibres.

According to this particular embodiment, the process more preferentially comprises the application, to the keratin fibres :

of the composition (A), then

- of the composition (B), then

of the composition (C),

or

of the composition (C), then

of the composition (A), then

- of the composition (B) .

Preferably with a time gap between the application o f the composition (A) and (B) .

The compositions (A) and (B) may also be mixed extemporaneously before their application to the keratin fibres. They may thus be kept, before application to the hair, in a compartment which does not contain oxygen. Oxygen from the air will then act directly on the hair. This embodiment makes it possible to reduce the number of steps to obtain pigmentation of the hair.

According to another particularly preferred embodiment, the additional metal salt(s) as defined above are present in the composition (A), and the process comprises the application o f the composition (A), followed by the application of the composition (B) .

Each of the compositions (A), (B) and optionally (C) is advantageously left in place on the keratin fibres for a duration ranging from 30 seconds to 1 hour, and more preferentially from 30 seconds to 30 minutes .

The process of the present invention may be repeated several times, especially from 2 to 50 times, preferably from 3 to 30 times, depending on the desired degree of co louring. The greater the number of applications, the more intense and darker is the co louring, thereby improving the repigmentation of grey hair.

Advantageously, the process of the invention is carried out by re-applying the compositions (A), (B) and optionally (C) several times, to obtain, over time, a natural and visible co louring. For example, the compositions according to the invention may be applied after each shampoo operation, or for example once or twice per week.

The process of the invention may also comprise a step o f rinsing after the application of the compositions (A) and (B) or after application o f the compositions (A), (B) and (C) .

More preferentially, the process comprises a single final rinsing step . In other words, the keratin fibres are only rinsed after the application o f the final composition. Device

The present invention relates to a multi-compartment device comprising :

a first compartment containing the composition (A) as defined above;

- a second compartment containing the composition (B) as defined above; and

optionally, a third compartment containing the composition (C) as defined above.

According to another embodiment of the device, the latter contains a compartment comprising a composition resulting from the mixing o f the composition (A) with the composition (B), this compartment not containing oxygen.

The device according to the present invention may also comprise : - an additional compartment containing the composition (C) as defined above, and/or

- an additional compartment containing a composition comprising a glucosidase.

The compositions o f the compartments are intended to be applied successively to the keratin fibres according to the process as described above.

Pigment

The present invention relates also to a pigment obtained by the reaction o f one or more ortho-dihydroxy- 1 ,2-diphenylethylene derivatives as defined above, of one or more manganese and/or zinc derivatives chosen from manganese salts or oxides and zinc salts or oxides as defined above, of one or more hydroxides and/or (hydrogen) carbonates as defined above, and o f one or more additional metal salts other than the manganese salts and zinc salts as defined above.

The hydroxides are chosen in particular from the hydroxides o f sodium, potassium and calcium. Preferably, calcium hydroxide is used.

In a particularly preferred embodiment according to the present invention, a catalytic amount of Mn²⁺ and/or Zn²⁺ salt is added to a so lution of ortho-dihydroxy- 1 ,2-diphenylethylene derivative in water and after 1 to 30 minutes, a so lution of sodium bicarbonate or calcium hydroxide is added. After 1 to 24 hours, a solution containing Fe^{2 +} salts is added. It is then left to stand for a period of time ranging from 1 minute to 24 hours and then a brown to black precipitate is iso lated by filtration, centrifugation or freeze-drying. This precipitate is optionally washed with water or with an organic so lvent such as ethano l, acetone or isopropanol and then dried.

In order to iso late the pigment of the invention, filtration fo llowed by drying can be carried out at the end o f the synthesis process.

The pigment thus prepared can be used in various applications where it is desired to have a brown to black pigment, such as, but not limited to , makeup products, sunscreen compositions and hair co louring products . A subject of the present invention is therefore compositions, in particular dyeing compositions, containing the pigment as described above.

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

EXAMPLES

In all the examples below, the colour of the locks was evaluated in the CIE L* a* b* system, using a Minolta Spectrophotometer CM2600D colorimeter.

In this L* a* b* system, the three parameters respectively denote the intensity of the colour (L*), the green/red colour axis (a*) and the blue/yellow colour axis (b*). The higher the value of L*, the lighter the colour. The higher the value of a*, the redder the colour and the higher the value of b*, the yellower the colour.

In the examples that follow, all the amounts are given as percentages by weight relative to the total weight of each composition. Example 1: according to the invention a. Compositions tested

The following compositions Al and B were prepared from ingredients whose contents are indicated in the tables below.

Composition Al :

Black shou wu is a natural extract enriched in THSG, prepared according to the preparation process described in patent application CN 103405516, and which contains from 15% to 30% by weight of THSG. It contains a total amount of polyphenols including THSG of 25% to 50% by weight.

The term THSG denotes 2,3,5,4'-tetrahydroxystilbene 2-Ο-β-ϋ- glucoside, which is a derivative of ortho-dihydroxy- 1 ,2- diphenylethylene of formula:

Composition B

b. Procedure

The compositions Al and B thus obtained were then applied, according to the protocol below, to locks of 100% grey Chinese hair, washed beforehand.

Protocol for an application:

Application of the composition Al by means of a brush at an amount of 500 μΐ of solution Al on 0.5 g locks. The locks were then left to take at 22°C for 15 minutes.

Application of an identical amount of composition B, namely 500 μΐ per 0.5 g lock. After 15 minutes leaving to take at 22°C , the locks of hair were rinsed in water then left to dry.

The above protocol was repeated once, 3 times or 30 times on the locks .

The co lour of the locks obtained was evaluated in the CIE L * a* b* system, using a Mino lta Spectrophotometer CM2600D co lorimeter. c. Results

The table below represents the co louring intensity values, evaluated in the L * a*b * system (mean value for 3 locks) .

The above results show that the process according to the present invention makes it possible to darken the hair from the first application.

The co louring is substantially blacker and more intense after 30 applications. Example 2 : according to the invention a. Compositions tested

The fo llowing compositions A2, B and C were prepared from ingredients whose contents are indicated in the tables below.

Composition A2 :

b. Procedure

The compositions A2, B and C thus obtained were then applied, according to the protocol below, to locks of Chinese hair ( 100% or 50% grey), washed beforehand.

Protocol for an application:

The composition A2 was firstly applied by means of a brush at an amount of 500 μΐ of so lution A2 to locks each weighing 0.5 g. The lo cks were then left to take at 22°C for 15 minutes .

An identical amount of composition B was then applied, namely 500 μΐ per 0.5 g lock. After 15 minutes leaving to take at 22°C, 1 ml of composition C was applied to the locks, and left to take for one minute.

The locks were then rinsed with water and then left to dry.

The above protocol was repeated once, 3 times or 30 times on the locks.

The colour of the locks obtained was evaluated in the CIE L* a* b* system, using a Minolta Spectrophotometer CM2600D colorimeter. c. Results

The tables below represent the colouring intensity values evaluated in the L*a*b* system (mean value for 3 locks), obtained from 100% grey hair (table 1) or 50% grey hair (table 2).

Table 1

L* a* b*

100% grey hair

before 67.2 1.15 20.33 treatment

After 1

55.6 0.91 12.92 application

After 3

41.33 0.79 9.55 applications

After 30

24.04 2.04 5.77 applications

Table 2

The above results show that the process according to the present invention makes it possible to darken 1 00% grey hair (table 1 ) and 50% grey hair (table 2) from the first applications ( 1 and 3 applications) .

Moreover, the co lourings are significantly darker and more intense after 30 applications .

Example 3 : comparative process without application of Fe salt a. Compositions tested

The compositions A2 and B were prepared from ingredients whose contents are indicated in the tables of example 2 above. b. Procedure

The compositions A2 and B obtained in this way were then applied to locks of 100% grey Chinese hair washed beforehand, according to the protocol of example 1 . d. Results

L* a* b*

100% grey hair 67.2 1 . 15 20.33 before

treatment

After 1

66.57 1 .43 19. 15 application

After 3

65.93 1 .74 1 8.29 applications

After 30

54.39 5.65 17.76 applications

The above results show that, unlike the process of the invention (example 2), this comparative process does not make it possible to rapidly dye the hair. Indeed, incipient dyeing is only perceived after 30 applications.

This comparative example shows that the presence o f the additional salt, in combination with the ortho-dihydroxy- 1 ,2- diphenylethylene derivative, the manganese and/or zinc salt(s) and the hydrogen carbonate, is necessary in order to obtain an intense dark co louring o f the hair.

Example 4 : use of piceatannol - comparative tests a. Compositions tested

The fo llowing compositions A3 and A4 were prepared from ingredients whose contents are indicated in the table below.

Piceatannol corresponds to 4- [(E)-2-(3 ,5 - dihydroxyphenyl)ethenyl]benzene- 1 ,2-dio l, which is an ortho- dihydroxy- 1 ,2-diphenylethylene derivative of formula:

b. Procedure

The 100% grey locks of hair are treated according to the protocol of example 1, with the compositions A3 or A4 and the composition B described in example 1. The protocol was carried out once.

The colours of the locks obtained were evaluated in the CIE L* a* b* system, using a Minolta Spectrophotometer CM2600D colorimeter. c. Results

The table below represents the colouring intensity values, evaluated in the L*a*b* system (mean value for 3 locks).

The results above show that the process according to the present invention makes it possible to darken the hair much more effectively than a first comparative process which does not employ hydrogen carbonate (application of the composition A3 alone) and than a second comparative process which does not employ an additional salt (application of the compositions A4 and B) .

Example 5 : preparation of a pigment from an extract of Black shou wu l g of B lack shou wu extract described in example 1 is added to 100 ml of a 10^"2 mo l/1 solution o f manganese gluconate. The mixture is left stirring for 1 hour at ambient temperature and in air. Then, 10 ml of a solution containing 8% by weight of active material o f KHCO3 are added. The mixture is stirred for 2 hours at ambient temperature and in air. An iron sulphate so lution o f 5 % by weight of active material is then added. The mixture is left under stirring for 24 hours. The precipitate obtained is filtered. The latter is washed 3 times with 50 ml of water before being dried. The pigment thus obtained is inso luble in water, ethano l, acetone, isopropano l and DMSO in a test which consists in adding 100 mg of pigment in 10 ml of so lvent at ambient temperature. Example 6 : composition o f wax/water mascara

The fo llowing wax/water mascara composition was prepared:

- Beeswax : 6 g

- Paraffin wax : 13 g

- Hydrogenated jojoba oil : 2 g

- Hydroxyethylcellulo se : 1 g

- Triethano lamine stearate : 8 g

- Black pigment according to Example 5 : 5 g

- Conservative qs

- Water qs 100 g

This composition was applied to locks of hair (0.5 g) . After 8 hours at room temperature, the locks were cleaned with a make-up remover for mascara (La Roche Posay Respectissime make-up remover water proof) and then rinsed with water. The same operation was repeated several times with the above composition.

The co lours of the lo cks obtained were evaluated in the CIE L * a* b* system, using a Mino lta Spectrophotometer CM2600D co lorimeter.

The results are expressed in the table below:

These results show a gradual staining o f the locks, remainin after removing makeup .

Claims

1. Process for treating keratin fibres, comprising the application, to said fibres, of one or more ortho-dihydroxy- 1 ,2- diphenylethylene derivatives, of one or more manganese and/or zinc derivatives chosen from manganese salts or oxides and zinc salts or oxides, of one or more (hydrogen) carbonates and of one or more additional divalent or trivalent metal salts other than the manganese salts and zinc salts.

2. Process according to Claim 1, characterized in that it comprises:

c) application, to the fibres, of the additional divalent or trivalent metal salt(s) other than the manganese salts and zinc salts, these additional metal salts being present in the composition (A) and/or in the composition (B) and/or in an additional separate composition (C).

3. Process according to either one of the preceding claims, characterized in that the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) are chosen from:

- glycosylated derivatives, such as 2,3,5,4'- tetrahydroxystilbene 2-0-P-D-glucoside; trans-3'- -glucopyranosyl-

4,5'-dihydroxy-3-methoxystilbene; trans-3'- -glucopyranosyl-3,4,5'- trihydroxystilbene; and piceatannol 3-glucoside;

- non-glycosylated derivatives, such as trans-3-methoxy- 3',4,5'-trihydroxystilbene; piceatannol (trans-3,3',4,5'- tetrahydroxystilbene); 5-[(lE)-2-phenylethenyl]-l,2,3-benzenetriol; 4- [( lZ)-2-(3, 5 -dihydroxyphenyl)ethenyl]-l ,2-benzenediol; 5-[(lE)-2-(4- hydroxyphenyl)ethenyl]-l ,2,3-benzenetriol; 5-[(lE)-2-(3,4- dihydroxyphenyl)ethenyl]-l ,2,3-benzenetriol; 4-[(lE)-2-(2,4- dihydroxyphenyl)ethenyl]-l ,2-benzenediol; α-[[(2Ε)-3-[2-[(1Ε)-2-(3,4- dihydroxyphenyl)ethenyl]-3 ,4-dihydroxyphenyl]- 1 -oxo-2-propen- 1 - yl]oxy]-3,4-dihydroxy-benzenepropanoic acid; ethyl 2-[(lE)-2-(3,4- dihydroxyphenyl)ethenyl]-6-hydroxy-benzoate and 4-[(lE)-2-(3,5- dimethoxyphenyl)ethenyl]- 1 ,2-benzenediol; and

- the optical and/or geometric isomers, the salts and/or solvates and the mixtures of such derivatives.

4. Process according to any one of the preceding claims, characterized in that the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) are chosen from glycosylated derivatives, and preferably the composition (A) comprises 2,3,5,4'-tetrahydroxystilbene 2-Ο-β-ϋ- glucoside.

5. Process according to any one of the preceding claims, characterized in that the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) are used in the form of plant extracts.

6. Process according to any one of Claims 2 to 5, characterized in that the total amount of the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives present in the composition (A) ranges:

- from 0.001% to 15% by weight, preferably from 0.01% to 10% by weight relative to the total weight of the composition (A), when the latter is liquid;

- from 1%) to 99% by weight, preferably from 10%> to 60%> by weight relative to the total weight of the composition (A), when the latter is solid.

7. Process according to any one of the preceding claims, characterized in that the manganese and/or zinc derivative(s) are chosen from manganese or zinc salts, and preferably from chlorides, fluorides, iodides, bromides, sulfates, phosphates, nitrates, perchlorates, carbonates, carboxylates, and mixtures thereof.

8. Process according to any one of the preceding claims, characterized in that it uses one or more Mn(II) salts, preferably chosen from manganese carboxylates, manganese halides and mixtures thereof, and more preferentially from manganese chloride, manganese gluconate and mixtures thereof.

9. Process according to any one of Claims 2 to 8, characterized in that the composition (A) comprises one or more manganese derivatives in a total concentration ranging from 10^"3 to 10^"1 mmol.l^"1, and preferably from 10^"2 to 10^"1 mmol.l^"1, expressed relative to a composition (A) in liquid form.

10. Process according to any one of Claims 2 to 9, characterized in that the composition (A) comprises one or more zinc derivatives in a total concentration ranging from 5.10^"2 to 10 mmol.l^"1, and preferably from 5.10^"1 to 1 mmol.l^"1, expressed relative to a composition (A) in liquid form.

11. Process according to any one of the preceding claims, characterized in that the (hydrogen) carbonate(s) are chosen from the compounds of the following formulae:

R'⁺, HCO3^" with Pv' representing a hydrogen atom, an alkali metal, an ammonium group Rⁿ4N⁺- or a phosphonium group R"₄P⁺- in which the groups R", which are identical or different, represent a hydrogen atom, an optionally substituted (Ci-C₆)alkyl group, such as hydroxyethyl; and

Met'²⁺ (HC03^")₂, with Met' representing an alkaline earth metal; and preferably from alkali metal hydrogen carbonates, alkaline earth metal hydrogen carbonates, ammonium hydrogen carbonates and mixtures thereof; and more preferentially from alkali metal hydrogen carbonates, alkaline earth metal hydrogen carbonates and mixtures thereof.

12. Process according to any one of Claims 2 to 11, characterized in that the composition (B) contains the (hydrogen) carbonate(s) in a total amount ranging from 0.1% to 15% by weight and preferably from 0.5% to 10% by weight relative to the total weight of the composition (B).

13. Process according to any one of the preceding claims, characterized in that the additional metal salt(s) are chosen from iron(II) salts and iron(III) salts, preferably from iron sulfate, iron fumarate, iron gluconate, iron acetylacetonate, iron oxalate, mixed salts, such as Mohr' s salt, and mixtures thereof; and better still, iron sulfate.

14. Process according to any one of the preceding claims, characterized in that the total amount of additional metal salt(s) ranges from 0.001 % to 5 % by weight and preferably from 0.01 % to 4% by weight relative to the total weight of the composition containing same.

15. Process according to any one of the preceding claims, characterized in that one or more glyco sylated derivatives o f tetrahydroxy- 1 ,2-diphenylethylene are used and in that it also comprises the use of an enzyme o f β-glucosidase type .

16. Process according to any one of Claims 2 to 15 , characterized in that the additional metal salt(s) are present in a composition (C) separate from the compo sitions (A) and (B), and the three compositions (A), (B) and (C) are applied successively to the keratin fibres.

17. Process according to Claim 1 6, characterized in that it comprises the application, to the keratin fibres :

- of the composition (A), then

- of the composition (B), then

- of the composition (C),

or

- of the composition (C), then

- of the composition (A), then

- of the composition (B) .

1 8. Process according to any one of Claims 2 to 15 , characterized in that the additional metal salt(s) are present in the composition (A), and the process comprises the app lication o f the composition (A), followed by the application of the composition (B) .

19. Multi-compartment device comprising :

- a first compartment containing the composition (A) as defined in any one of Claims 2 to 10, 13 and 14;

a second compartment containing the composition (B) as defined in either one of Claims 1 1 and 12; and optionally, a third compartment containing the composition (C) as defined in any one of Claims 2, 1 3 and 14.

20. Pigment obtained by the reaction of one or more ortho- dihydroxy- 1 ,2-diphenylethylene derivatives, of one or more manganese and/or zinc derivatives chosen from manganese salts or oxides and zinc salts or oxides, of one or more hydroxides and/or (hydrogen) carbonates, and o f one or more additional metal salts other than the manganese salts and zinc salts .

21 . Dyeing composition comprising a pigment as defined in Claim 20.