WO2017109186A1 - Method for extracting metal ions from keratinous fibres by repeated application of an acid composition - Google Patents

Abstract

The present invention relates to a process for the extraction of minerals from keratinous fibres, in particular human keratinous fibres, such as the hair, comprising at least two successive stages of application of a composition comprising at least one acid in a content of greater than at least 1% by weight and at least one liquid compound having a value of the Hansen solubility parameter δH of less than 16 MPa^1/2.

Description

Method for extracting metal ions from keratinous fibres by repeated application of an acid composition

The present invention relates to a process for the extraction o f metal ions from keratinous fibres, in particular human keratinous fibres, such as the hair, comprising at least two successive stages o f application o f a composition comprising at least one acid in a content of greater than or equal to 0.5 % by weight and at least one liquid compound having a value o f the Hansen so lubility parameter δΗ o f less than 16 MPa^{1 /2}.

Consumers over the who le world are generally in contact with highly varied sources o f water which are not without impact on the hair, in particular with regard to their cosmetic properties, and/or the performance levels of hair products .

"Mineral" waters contain, for examp le, variable amounts o f minerals present in the form o f dissolved ions, such as calcite (present in the form o f calcium), dolomite (present in the form o f calcium and magnesium), magnetite (present in the form o f iron) and chalcanthite (present in the form o f copper) . "Hard" waters are also concentrated in minerals, such as calcium and magnesium, and swimming pool waters are for their part concentrated in copper salts originating from algicides used in the treatment of swimming pools.

Hair has a strong tendency to absorb these minerals and the metal salts because o f the presence, at their surface, of anionic functional groups which correspond in particular to the sulfonic or carboxylic functional groups o f keratin. Furthermore, the isoelectric point o f the hair is generally described between 3.2 and 4. The result of this is that, in everyday life, the pH of the water applied to the hair is greater than such values, which results in a negatively charged fibre.

Minerals, very o ften polyvalent cations, will thus be attracted and captured by this negatively charged fibre with the formation o f chemical bonds, sometimes strong chemical bonds, which prevent them from being released by conventional hair treatment methods . This results in a possible accumulation of minerals on the hair with the passage of time. Such an attaching depends not only on the duration o f exposure of the hair to the water in question but also on the nature and the length of the hair (porosity and charge) .

The accumulation o f these minerals and/or of metal salts, in particular of alkali metal, alkaline earth metal or transition metal salts , can result in modifications to the hair fibre and in particular in a more or less marked modification o f the cosmetic properties o f the hair. Thus, an accumulation o f calcium and of magnesium can result in dry hair lacking in glo ss, whereas an accumulation of copper can result in the hair turning pale.

In addition, the accumulation o f the metal (iron, copper) salts can also accelerate the damage caused to the hair as the latter catalyse oxidation/reduction reactions and generate hydroxyl radicals HO° which can be harmful to the fibre, including at low contents . This thus results in a photodegradation o f the fibre, a lightening, indeed even a breaking, o f the hair, which are observed in particular during the subsequent use o f lightening products, or a change in the co lourings which may be observed during the subsequent use of dyeing products .

In other words, hair enriched in metal salts and minerals can have a tendency to break and/or to turn lighter in an undesirable way subsequent to the application of a conventional lightening composition or can have a tendency to bring about a change in co louring subsequent to the application of a conventional dyeing composition.

There thus exists a rea l need to emp loy a met hod ca pab l e o f extracting the metal ions, resulting from minerals and metal salts disso lved in water, from keratinous fibres in order to limit their negative impacts and to overcome all o f the abovementioned disadvantages .

This aim is achieved by virtue o f the imp lementation o f a method for extracting metal ions from keratinous fibres, in particular from human keratinous fibres, such as the hair, comprising at least two successive stages o f application, to the said fibres, o f a composition comprising :

a) one or more acids in a content of greater than or equal to 0.5 % by weight, with respect to the total weight of the composition; and

b) one or more liquid compounds having a value o f the Hansen so lubility parameter δΗ of less than 16 MPa^{1 /2}.

Thus, a subj ect-matter of the invention is in particular a method for the treatment of keratinous fibres, in particular human keratinous fibres, such as the hair, comprising at least two successive stages of application o f a composition as defined above.

This is because the method according to the invention makes it possible to efficiently extract metal ions, resulting from minerals and metal salts disso lved in water, from keratinous fibres. The method according to the invention exhibits in particular the advantage o f resulting in high levels of yield for extraction of metal ions .

Thus, the method according to the invention makes it possible to significantly limit the undesirable lightening o f keratinous fibres brought about by the presence o f metal ions, in particular copper ions, within the said fibres subsequent to a lightening treatment o f the keratinous fibres.

In particular, the method according to the invention makes it possible to bring the lightening o f keratinous fibres enriched in metal ions back to a level similar to that of lightened keratinous fibres not enriched in metal ions .

In the same way, the method according to the invention makes it possible to significantly limit the breaking o f keratinous fibres brought about by the presence o f metal ions, in particular copper ions, within the said fibres subsequent, for example, to a lightening and/or chemical or natural oxidizing treatment of the keratinous fibres.

In other words, the method according to the invention makes it possible to prevent the undesirable lightening and/or the breaking o f keratinous fibres brought about by the accumulation o f metal ions . In addition, the method according to the invention makes it possible to significantly limit the change in co louring o f keratinous fibres brought about by the presence of metal ions, in particular copper ions, observed subsequent to a dyeing treatment of the fibres .

In particular, the method according to the invention makes it possible to bring the level of colouring of keratinous fibres enriched in metal ions back to a level similar to that of dyed keratinous fibres not enriched in metal ions .

In other words, the method according to the invention makes it possible to prevent the change in co louring of keratinous fibres enriched in metal ions which are subsequently dyed using a dyeing method.

The present invention also relates to a process for lightening human keratinous fibres, such as the hair, comprising at least two successive stages o f application, to the said fibres, of a composition as defined above, and at least one stage of lightening the said fibres .

Likewise, another subject-matter of the invention is a method for dyeing human keratinous fibres, such as the hair, comprising at least two successive stages of application, to the said fibres, o f a composition as defined above, and at least one stage o f dyeing the said fibres .

Other subj ect-matters, characteristics, aspects and advantages of the invention will emerge even more clearly on reading the description and the examples which follow.

Artificially lightened keratinous fibres is understood to mean, within the meaning of the present invention, keratinous fibres which have been lightened subsequent to a method for lightening keratinous fibres.

Artificially dyed keratinous fibres is understood to mean, within the meaning of the present invention, keratinous fibres which have been dyed subsequent to a method for the direct dyeing or a method for the oxidation dyeing o f keratinous fibres. In that which will follow, and unless otherwise indicated, the limits of a range of values are included within this range, in particular 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 or equal" respectively.

Composition The composition employed in the method according to the invention comprises : a) one or more acids in a content of greater than or equal to 0.5% by weight, with respect to the total weight of the said composition

Preferably, the acid exhibits a pK_a o f less than 4, in particular a pK_a o f less than 3.5 and better still a pK_a of less than 3.

The acid can be organic or inorganic.

Organic acid is understood to mean any non-polymeric organic compound comprising one or more acid functional groups chosen from carboxylic acid, sulfonic acid and phosphonic acid functional groups .

Preferably, the organic acid is not a surfactant.

More preferably still, the mo lecular weight of the organic acid is less than 250 and better still less than 200.

The organic acids can be amino acids .

Preferably, the organic acid exhibits one or more carboxyl functional groups .

According to a specific embodiment, the acid or acids o f the invention are chosen from acids having one or more carboxyl functional groups, such as the carboxylic acids of fo llowing formula

(I) :

in which formula (I) or one of its salts:

- A represents a saturated or unsaturated, cyclic or non-cyclic and aromatic or non-aromatic hydrocarbon group comprising from 1 to 50 carbon atoms which is monovalent when n has the value 0 or polyvalent when n is greater than or equal to 1, which group is optionally interrupted by one or more heteroatoms and/or optionally substituted, in particular by one or more hydroxyl groups; preferably, A represents a monovalent (Ci-C₆)alkyl group or a polyvalent (Ci- C₆)alkylene group optionally substituted by one or more hydroxyl groups;

- n represents an integer between 0 and 10 inclusive; preferably, n is between 0 and 5, such as between 0 and 2. The organic acid or acids are preferably chosen from acetic acid, propanoic acid, butanoic acid, lactic acid, malic acid, glycolic acid, ascorbic acid, maleic acid, phthalic acid, succinic acid, serine, taurine, tartaric acid, arginine, glycine, glucuronic acid, gluconic acid, citric acid and their mixtures.

In particular, the acid or acids of the invention are chosen from a-hydroxy acids and a-amino acids; preferably, the acid is chosen from citric acid, lactic acid, malic acid, tartaric acid, glycolic acid and serine, more preferably from lactic acid and glycolic acid.

More preferably, the organic acid or acids are chosen from glycolic acid, citric acid or their mixture.

According to another specific embodiment of the invention, the acid or acids are chosen from sulfonic or phosphonic acid functional groups. Mention may be made, among these acids, for example, of taurine or para-toluenesulfonic acid.

According to another specific embodiment of the invention, the acid or acids are chosen from inorganic acids and in particular from phosphorus-based acids, such as phosphoric acid, halogen-based acids, such as hydrochloric acid, and sulfur-based acids, such as sulfuric acid, and their mixtures .

More preferably, the inorganic acid is hydrochloric acid.

Preferably, the composition employed during the metho d according to the invention contains an acid chosen from organic acids having one or more carboxyl functional groups and inorganic acids .

According to an alternative form o f the invention, the composition employed during the method according to the invention contains an acid chosen from a mixture of organic acids having one or more carboxyl functional groups and inorganic acids .

The acid or acids are preferably present in the composition employed during the method according to the invention in an amount varying from 0.5 % to 20%> by weight, preferably from 0.6%> to 1 8 % by weight and more preferably still in an amount varying from 1 % to 15 % by weight, with respect to the total weight of the composition.

The pH o f the acid composition according to the invention is preferably between 0.5 and 5 , better still between 0.5 and 3 and even better still between 0.5 and 2.7. b) one or more liquid compounds having a value of the Hansen solubility parameter δΗ of less than 16 MP a¹¹²

In the context of the present invention, such a compound is also known as a "hydrotropic compound" .

Hydrotropic compound is understood to mean, within the meaning of the present invention, a compound liable to increase the so lubility o f hydrophobic compounds in aqueous phases .

Preferably, the liquid compound or compounds exhibit a value of the Hansen so lubility parameter δΗ o f greater than 0 and less than 16 MPa^{1 /2}.

The liquid compound or compounds more preferably exhibit a Hansen so lubility parameter δΗ o f between 5 and 15 .8 MPa^{1 /2}, more preferably still between 8 and 15.8 MPa and better still between 8 and 15 MPa^1/2.

These compounds are liquid at a temperature of 25°C and at atmospheric pressure (760 mmHg; i.e. 1.013 x 10⁵ Pa).

The compound or compounds exhibiting a value as defined above of the Hansen solubility parameter δΗ are, for example, described in the reference publication Hansen solubility parameters: A User's Handbook, Charles M. Hansen, CRC Press, 2000, pages 167 to 185, or else in the publication Handbook of Solubility Parameters and Other Cohesion Parameters, CRC Press, pages 95 to 121 and pages 177 to 185.

This value of the solubility parameter δΗ is related to the formation of hydrogen bonds. It may be recalled that there exist three major types of interactions in organic compounds: non-polar interactions, permanent dipole-dipole interactions and interactions of hydrogen bond type, these interactions forming the subject of the parameter defining the hydrotropic compound present in the composition employed in accordance with the invention.

In particular, the publication Handbook of Solubility Parameters and Other Cohesion Parameters, CRC Press, pages 95 to 121 and pages 177 to 185, gives the equation δΗ = (∑-^zU_h/V)^1/2

where ^zUh (in J.mol^"1) describes the contributions of the functional group under consideration in the solubility parameters related to the hydrogen bonds (values in Table 14, page 183), this parameter ^zUh also being described in the publication The relation between surface tension and solubility parameter in liquids, Bagda, E, Farbe Lack, 84, 212, 1978; and V is the volume of the molecule.

It should be noted that the value of the solubility parameter δΗ is usually given for a temperature of 25°C and at atmospheric pressure (760 mmHg, i.e. 1.013 10⁵ Pa).

In particular, the liquid compounds exhibiting a value of the Hansen solubility parameter δΗ of less than 16 MPa^1/2 are non-ionic organic compounds. The said liquid compound or compounds exhibiting a value of the Hansen solubility parameter δΗ of less than 16 MPa^1/2 can be chosen from:

• alcohol ethers, in particular C1-C4 ethers of C5-C30 alcohols, which are preferably saturated, linear or branched, optionally interrupted by one or more non-adjacent ether functional groups;

• aliphatic esters of C1-C4 carboxylic acids and of mono- or polyhydroxylated C3-C10 alcohols, interrupted by one or more non- adjacent ether functional groups;

• aromatic ethers, in particular C₆-Cio aromatic ethers, of a Ci-C₆ alkyl optionally carrying a hydroxyl group,

• (C6-Cio)aryl(Ci-Ce)alkyl ethers of a Ci-C₆ alkyl optionally carrying a hydroxyl group,

• alkanols having aryl substituents, preferably for which the aryl part is a C₆-Cio aryl part, advantageously a C₆ aryl part, and the alkyl part of the alkanol is a C1-C4 alkyl part, it being possible for this alkyl part to be terminated or interrupted by a heteroatom, advantageously oxygen, or a hydroxyl group, preferably such as benzyl alcohol;

• lactones, preferably of formula (iii), and also their mixtures :

in which R' represents a hydrogen, a linear or branched Ci-Cs alkyl or a linear or branched C1-C4 hydroxyalkyl and n has the value 1, 2 or 3, and preferably R' represents a hydrogen, a linear or branched Ci-C₆ alkyl or a linear or branched C1-C2 hydroxyalkyl.

Mention may be made, as particularly advantageous example of lactones, of γ-butyrolactone.

Mention may also be made of certain liquid alkanols, such as, for example, 1-pentanol.

Preferably, the said liquid compound or compounds exhibiting a value of the Hansen solubility parameter δΗ of less than 16 MPa^1/2 are chosen from alcohol ethers, aliphatic esters, aromatic ethers, alkanols having aryl substituents and their mixtures.

More preferably still, the said liquid compound or compounds according to the invention are chosen from dipropylene glycol monomethyl ether acetate, dipropylene glycol methyl ether, dipropylene glycol mono(n-butyl) ether (the INCI name of which is PPG-2 Butyl Ether), tripropylene glycol methyl ether, propylene glycol n-butyl ether, propylene glycol n-propyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether and monoethyl ether, 3-phenyl-l-propanol, 2-phenyl- 1 -propanol, benzyl alcohol, benzyloxyethanol, phenoxyethanol, phenylethanol and the mixtures of these compounds.

The liquid compound(s) exhibiting a value of the Hansen solubility parameter δΗ of less than 16 MPa^1/2 is/are more preferably still chosen from alcohol ethers and alkanols having aryl substituents and more preferably still dipropylene glycol methyl ether, propylene glycol monobutyl ether and benzyl alcohol, phenylethanol or phenoxyethanol, better still alkanols having an aryl substituent, such as benzyl alcohol, phenylethanol or phenoxyethanol.

Preferably, the liquid compound exhibiting a value of the

Hansen solubility parameter δΗ of less than 16 MPa^1/2 is chosen from alkanols having aryl substituents.

More preferably, the liquid compound exhibiting a value of the Hansen solubility parameter δΗ of less than 16 MPa^1/2 is benzyl alcohol.

Preferably, the liquid compound(s) exhibiting a value of the Hansen solubility parameter δΗ of less than 16 MPa^1/2 represent a total content varying from 0.1% to 35% by weight, preferably from 0.5% to 20%) by weight and better still from 0.5%> to 10%> by weight, with respect to the total weight of composition.

According to a preferred embodiment, the composition comprises:

- one or more acids chosen from organic acids having one or more carboxyl functional groups and/or inorganic acids, the said acids being in a content of at least 0.5 % by weight, with respect to the total weight of the composition,

- one or more liquid compounds having a value o f the Hansen so lubility parameter δΗ o f less than 1 6 MPa^{1 /2} chosen from alcoho l ethers and alkanols having aryl substituents .

In accordance with this embodiment, the organic acids having one or more carboxyl functional groups preferably exhibit one, two or three carboxyl functional groups .

In accordance with this embo diment, the acid or acids are preferably chosen from hydrochloric acid, glyco lic acid and citric acid. More preferably, the acid or acids are preferably chosen from hydrochloric acid or a mixture of glycolic acid and citric acid.

In accordance with this embodiment, the liquid compounds are preferably chosen from dipropylene glycol methyl ether and benzyl alcoho l. More preferably, the liquid compound or compounds are chosen from alkano ls having aryl substituents, in particular benzyl alcoho l, phenylethanol or phenoxyethanol. c) one or more surfactants

According to a specific embodiment, the composition employed in the method according to the invention additionally contains c) one or more surfactants .

The surfactant or surfactants which can be used in the composition according to the invention can be chosen from non-ionic, cationic, anionic and amphoteric or zwitterionic surfactants .

The composition according to the present invention can comprise one or more non-ionic surfactants .

The non-ionic surfactants which can be used are described, for example, in the Handbook of Surfactants by M.R. Porter, published by Blackie & Son (Glasgow and London), 1 991 , pp . 1 16- 178.

Mention may be made, as examples of non-ionic surfactants, o f the fo llowing non-ionic surfactants :

- oxyalkylenated (Cs- C 24)alkylphenols; - saturated or unsaturated, linear or branched and oxyalkylenated or glycerolated Cs to C40 alcohols, comprising one or two fatty chains;

saturated or unsaturated, linear or branched and oxyalkylenated Cs to C30 fatty acid amides;

- esters of saturated or unsaturated and linear or branched Cs to C30 acids and of polyethylene glycols;

- preferably oxyethylenated esters of saturated or unsaturated and linear or branched Cs to C30 acids and of sorbitol;

- esters of fatty acids and of sucrose;

(C8-C3o)alkyl(poly)glucosides, (Cs- C3o)alkenyl(poly)glucosides, which are optionally oxyalkylenated (0 to 10 oxyalkylene units) and comprising from 1 to 15 glucose units, (Cs- C3o)alkyl(poly)glucoside esters;

- saturated or unsaturated and oxyethylenated vegetable oils;

- condensates of ethylene oxide and/or of propylene oxide;

N-(C8-C3o)alkylglucamine and N-(Cs-

C3o)acylmethylglucamine derivatives;

- aldobionamides;

- amine oxides;

- oxyethylenated and/or oxypropylenated silicones;

- and their mixtures.

The oxyalkylene units are more particularly oxyethylene or oxypropylene units, or their combination, preferably oxyethylene units.

The number of moles of ethylene oxide and/or of propylene oxide preferably ranges from 1 to 250, more particularly from 2 to 100 and better still from 2 to 50; the number of moles of glycerol ranges in particular from 1 to 50 and better still from 1 to 10.

Advantageously, the non-ionic surfactants according to the invention do not comprise oxypropylene units.

Use is preferably made, as examples of glycerolated non-ionic surfactants, of mono- or polyglycerolated Cs to C40 alcohols comprising from 1 to 50 mol of glycerol and preferably from 1 to 10 mol of glycerol.

Mention may be made, as examples of compounds of this type, of lauryl alcohol comprising 4 mol of glycerol (INCI name: Polyglyceryl-4 Lauryl Ether), lauryl alcohol comprising 1.5 mol of glycerol, oleyl alcohol comprising 4 mol of glycerol (INCI name: Polyglyceryl-4 Oleyl Ether), oleyl alcohol comprising 2 mol of glycerol (INCI name: Polyglyceryl-2 Oleyl Ether), cetearyl alcohol comprising 2 mol of glycerol, cetearyl alcohol comprising 6 mol of glycerol, oleocetyl alcohol comprising 6 mol of glycerol and octadecanol comprising 6 mol of glycerol.

Preference is more particularly given, among the glycerolated alcohols, to the use of the Cs/Cio alcohol comprising 1 mol of glycerol, the C₁₀/C₁₂ alcohol comprising 1 mol of glycerol and the C₁₂ alcohol comprising 1.5 mol of glycerol.

The non-ionic surfactant or surfactants which can be used in the composition according to the invention are preferably chosen from:

- oxyethylenated Cs to C₄o alcohols comprising from 1 to 100 mol of ethylene oxide, preferably from 2 to 50 and more particularly from 2 to 40 mol of ethylene oxide and comprising one or two fatty chains;

- saturated or unsaturated oxyethylenated vegetable oils comprising from 1 to 100 and preferably from 2 to 50 mol of ethylene oxide;

- (C8-C3o)alkyl(poly)glucosides which are optionally oxyalkylenated (0 to 10 EO) and which comprise 1 to 15 glucose units;

- mono- or polyglycerolated Cs to C₄o alcohols comprising from 1 to 50 mol of glycerol and preferably from 1 to 10 mol of glycerol;

saturated or unsaturated, linear or branched and oxyalkylenated Cs to C30 fatty acid amides;

- esters of saturated or unsaturated and linear or branched Cs to C30 acids and of polyethylene glycols;

- and their mixtures. The composition according to the present invention can comprise one or more cationic surfactants .

"Cationic surfactant" is understood to mean a surfactant which is positively charged when it is present in the compositions according to the invention. This surfactant can carry one or more permanent positive charges or can contain one or more cationizable functional groups within the compositions according to the invention.

The cationic surfactant or surfactants are preferably chosen from primary, secondary or tertiary fatty amines which are optionally polyoxyalkylenated, or their salts, quaternary ammonium salts, and their mixtures.

The fatty amines generally comprise at least one Cs to C30 hydrocarbon chain.

Mention may in particular be made, as quaternary ammonium salts, for example, of:

- those corresponding to the following general formula (II) :

(Π)

in which the R28 to R3 1 groups, which can be identical or different, represent a linear or branched aliphatic group comprising from 1 to 30 carbon atoms, or an aromatic group, such as aryl or alkylaryl, at least one of the R28 to R3 1 groups denoting a group comprising from 8 to 30 carbon atoms and preferably from 12 to 24 carbon atoms . The aliphatic groups can comprise heteroatoms, such as, in particular, oxygen, nitrogen, sulfur and halogens . The aliphatic groups are chosen, for example, from C i to C30 alkyl, C i to C30 alkoxy, polyoxy(C₂- C₆)alkylene, C i to C30 alkylamide, (C i ₂-C₂2)alkylamido(C₂ - C6)alkyl, (C i 2-C₂₂)alkyl acetate and C i to C30 hydroxyalkyl groups, X^" is an anion chosen from the group of halides, phosphates, acetates, lactates, (C i -C4)alkyl sulfates and (C i -C4)alkyl- or (C i -C4)alkylarylsulfonates. Preference is given, among the quaternary ammonium salts of formula (II), to, on the one hand, tetraalkylammonium salts, such as, for example, dialkyldimethylammonium or alkyltrimethylammonium salts in which the alkyl group comprises approximately from 12 to 22 carbon atoms, in particular behenyltrimethylammonium, distearyldimethylammonium, cetyltrimethylammonium or benzyldimethylstearylammonium salts, or else, on the other hand, to palmitylamidopropyltrimethylammonium salts, stearamidopropyltrimethylammonium salts, stearamidopropyldimethylcetearylammonium salts or stearamidopropyldimethyl(myristyl acetate)ammonium salts which is sold under the name Ceraphyl^® 70 by Van Dyk. It is preferable in particular to use the chloride salts of these compounds.

- quaternary ammonium salts of imidazoline, such as, for example, those of following formula (III):

(III) in which:

- P32 represents an alkenyl or alkyl group comprising from 8 to 30 carbon atoms, for example derived from tallow fatty acids,

- P33 represents a hydrogen atom, a Ci to C₄ alkyl group or an alkenyl or alkyl group comprising from 8 to 30 carbon atoms,

- P3₄ represents a Ci to C₄ alkyl group,

- P35 represents a hydrogen atom or a Ci to C₄ alkyl group,

- X^" is an anion chosen from the group of halides, phosphates, acetates, lactates, alkyl sulfates and alkyl- or alkylarylsulfonates, the alkyl and aryl groups of which preferably comprise, respectively, from 1 to 20 carbon atoms and from 6 to 30 carbon atoms. Preferably, R32 and R33 denote a mixture of alkenyl or alkyl groups comprising from 12 to 21 carbon atoms, for example derived from tallow fatty acids, R34 denotes a methyl group and R35 denotes a hydrogen atom. Such a product is so ld, for examp le, under the name Rewoquat^® W 75 by Rewo .

- quaternary di- or triammonium salts, in particular o f formula

(IV) :

(IV) in which:

- R36 denotes an alkyl radical comprising approximately from 16 to 30 carbon atoms which is optionally hydroxylated and/or interrupted by one or more oxygen atoms,

- R37 is chosen from hydrogen, an alkyl radical comprising from 1 to 4 carbon atoms or an (R36a) (R37a) (R38 a)N-(CH2)3 group,

- R36a, R37a, R38 a, R38 , R39 , R40 and R₄ 1 , which are identical or different, are chosen from hydrogen and an alkyl radical comprising from 1 to 4 carbon atoms, and

- X^" is an anion chosen from the group of halides, acetates, phosphates, nitrates and methyl sulfates.

Such compounds are, for example, Finquat CT-P provided by Finetex (Quaternium 89) and Finquat CT provided by Finetex (Quaternium 75),

- quaternary ammonium salts containing at least one ester functional group , such as those of following formula (V) : (C_sH_2sO)_z— R

O '45

X

R₄₄— C— (OC_rH_2r)_y - N (C_tH_2tO)_x - R,

^R42 in which:

- R42 is chosen from C i to C₆ alkyl groups and C i to Ci hydroxyalkyl or dihydroxyalkyl groups;

- R43 is chosen from:

O

- the group ⁴⁶

- R47 groups , which are saturated or unsaturated and linear or branched C i to C22 hydrocarbon groups,

- a hydrogen atom,

- R45 is chosen from:

O

- the group ⁴⁸

- R49 groups, which are saturated or unsaturated and linear or branched C i to C₆ hydrocarbon groups,

- a hydrogen atom,

- R44 , R46 and R48 , which are identical or different, are chosen from saturated or unsaturated and linear or branched C7 to C21 hydrocarbon groups,

- r, s and t, which are identical or different, are integers having values from 2 to 6,

- y is an integer having a value from 1 to 1 0,

- x and z, which are identical or different, are integers having values from 0 to 1 0,

- X^" is a simp le or complex and organic or inorganic anion, with the proviso that the sum x + y + z has a value from 1 to

15 , that, when x has the value 0, then R43 denotes R47 and that, when z has the value 0, then R45 denotes R49. The R42 alkyl groups can be linear or branched and more particularly linear.

Preferably, R42 denotes a methyl, ethyl, hydroxyethyl or dihydroxypropyl group and more particularly a methyl or ethyl group .

Advantageously, the sum x + y + z has a value from 1 to 1 0.

When R43 is an R47 hydrocarbon group, it can be long and have from 12 to 22 carbon atoms or be short and have from 1 to 3 carbon atoms.

When R45 is an R49 hydrocarbon group, it preferably has from 1 to 3 carbon atoms .

Advantageously, R44 , R46 and R48 , which are identical or different, are chosen from saturated or unsaturated and linear or branched C n to C21 hydrocarbon groups and more particularly from saturated or unsaturated and linear or branched C n to C21 alkyl and alkenyl groups .

Preferably, x and z, which are identical or different, have the value 0 or 1 .

Advantageously, y is equal to 1 .

Preferably, r, s and t, which are identical or different, have the value 2 or 3 and more particularly still are equal to 2.

The X^" anion is preferably a halide (chloride, bromide or iodide) or an alkyl sulfate, more particularly methyl sulfate . However, use may be made o f methanesulfonate, phosphate, nitrate, tosylate, an anion derived from an organic acid, such as acetate or lactate, or any other anion which is compatible with the ammonium having an ester functional group .

The X^" anion is more particularly still chloride or methyl sulfate.

Use is more particularly made, in the dyeing composition according to the invention, of the ammonium salts of formula (V) in which:

R42 denotes a methyl or ethyl group,

x and y are equal to 1 ,

z is equal to 0 or 1 , r, s and t are equal to 2 ,

R43 is chosen from:

O

- the group ⁴⁶

- methyl, ethyl or C _{1 4} to C 22 hydrocarbon groups,

- a hydrogen atom,

R45 is chosen from:

O

R,

- the group ⁴⁸

- a hydrogen atom,

R44 , R46 and R48 , which are identical or different, are chosen from saturated or unsaturated and linear or branched C 13 to C _{1 7} hydrocarbon groups and preferably from saturated or unsaturated and linear or branched C 13 to C _{1 7} alkyl and alkenyl groups .

Advantageously, the hydrocarbon groups are linear.

Mention may be made, for example, of the compounds o f formula (V), such as the diacyloxyethyldimethylammonium, diacyloxyethylhydroxyethylmethylammonium,

monoacyloxyethyldihydroxyethylmethylammonium,

triacyloxyethylmethylammonium or monoacyloxyethylhydroxyethyldimethylammonium salts (in particular chloride or methyl sulfate), and their mixtures. The acyl groups preferably have from 14 to 1 8 carbon atoms and originate more particularly from a vegetable oil, such as palm oil or sunflower oil . When the compound contains several acyl groups, the latter can be identical or different.

These products are obtained, for example, by direct esterification o f triethano lamine, triisopropanolamine, alkyldiethano lamine or alkyldiisopropanolamine, which are optionally oxyalkylenated, with C 10 to C30 fatty acids or with mixtures o f C 10 to C30 fatty acids o f vegetable or animal origin, or by transesterification of their methyl esters. This esterification is fo llowed by a quaternization using an alkylating agent, such as an alkyl halide (preferably a methyl or ethyl halide), a dialkyl sulfate (preferably a dimethyl or diethyl sulfate), methyl methanesulfonate, methyl para- toluenesulfonate, glycol chlorohydrin or glycero l chlorohydrin.

Such compounds are, for example, so ld under the names Dehyquart^® by Henkel, Stepanquat^® by Stepan, Noxamium^® by CECA and Rewoquat^® WE 1 8 by Rewo-Witco .

The dyeing composition according to the invention can contain, for example, a mixture o f quaternary ammonium mono-, di- and triester salts with a majority by weight of diester salts.

Use may also be made o f the ammonium salts containing at least one ester functional group which are described in Patents US-A-4 874 554 and US-A-4 137 1 80.

Use may be made o f behenoylhydroxypropyltrimethylammonium chloride, provided by Kao under the name Quatarmin BTC 13 1 .

Preferably, the ammonium salts containing at least one ester functional group contain two ester functional groups .

Preference is given, among the quaternary ammonium salts containing at least one ester functional group which can be used, to dipalmitoylethylhydroxyethylmethylammonium salts.

The cationic surfactants are preferably chosen from those o f formula (II) and those o f formula (V) and more preferably still from those of formula (II) .

The dyeing composition according to the present invention can comprise one or more anionic surfactants .

"Anionic surfactant" is understood to mean a surfactant comprising, as ionic or ionizable groups, only anionic groups. These anionic groups are preferably chosen from -COOH, -COO-, - S O3H, - S O3-, -O S O3H, -O S O3 -, -PO2H2 , -PO2H-, -PO2^{2 "}, -P(OH)₂, =P(0)OH, - P(OH)0-, =P(0)0-, =POH and =PO groups, the anionic parts comprising a cationic counterion, such as an alkali metal, an alkaline earth metal or an ammonium.

Mention may be made, as examples of anionic surfactants which can be used in the dyeing composition according to the invention, o f alkyl sulfates, alkyl ether sulfates, alkylamido ether sulfates, alkylaryl polyether sulfates, monoglyceride sulfates, alkylsulfonates, alkylamidesulfonates, alkylarylsulfonates, a- olefinsulfonates, paraffinsulfonates, alkyl sulfo succinates, alkyl ether sulfosuccinates, alkylamide sulfo succinates, alkyl sulfo acetates, acyl sarcosinates, acyl glutamates, alkyl sulfo succinamates, acyl isethionates and N-acyltaurates, salts of alkyl monoesters o f polyglucoside-polycarboxylic acids, acyl lactylates, D-galactoside- uronic acid salts, alkyl ether carboxylic acid salts, alkylaryl ether carboxylic acid salts, alkylamido ether carboxylic acid salts, and the corresponding non-salified forms of all these compounds, the alkyl and acyl groups o f all these compounds comprising from 6 to 40 carbon atoms and the aryl group denoting a phenyl group .

These compounds can be oxyethylenated and then preferably comprise from 1 to 50 ethylene oxide units.

The salts o f C₆ to C24 alkyl monoesters of po lyglucoside- polycarboxylic acids can be chosen from C₆ to C24 alkyl polyglucoside-citrates, C₆ to C24 alkyl polyglucoside-tartrates and C₆ to C24 alkyl po lyglucoside-sulfo succinates .

When the anionic surfactant or surfactants are in the salt form, they can be chosen from alkali metal salts, such as the sodium or potassium salt and preferably the sodium salt, the ammonium salts, amine salts and in particular amino alcohol salts, or alkaline earth metal salts, such as the magnesium salts.

Mention may in particular be made, as examples o f aminoalcoho l salts, o f the mono-, di- and triethano lamine salts, the mono-, di- or triisopropanolamine salts, the 2-amino-2-methyl- 1 - propanol salts, the 2-amino-2-methyl- 1 ,3 -propanediol salts and the tris(hydroxymethyl)amino methane salts .

Use is preferably made o f alkali metal or alkaline earth metal salts and in particular of the sodium or magnesium salts.

Use is preferably made, among the anionic surfactants mentioned, of (C₆ - C24)alkyl sulfates or of (C₆ - C24)alkyl ether sulfates comprising from 2 to 50 ethylene oxide units, in particular in the form of alkali metal, ammonium, aminoalcohol and alkaline earth metal salts, or of a mixture of these compounds.

In particular, it is preferable to use (Ci2-C2o)alkyl sulfates or (Ci2-C₂o)alkyl ether sulfates comprising from 2 to 20 ethylene oxide units, in particular in the form of alkali metal, ammonium, aminoalcohol and alkaline earth metal salts, or a mixture of these compounds. Better still, it is preferable to use sodium lauryl ether sulfate comprising 2.2 mol of ethylene oxide.

The composition according to the present invention can comprise one or more amphoteric or zwitterionic surfactants.

In particular, the amphoteric or zwitterionic surfactant or surfactants, which are preferably non-silicone, which can be used in the compositions according to the present invention can in particular be derivatives of optionally quaternized secondary or tertiary aliphatic amines, in which derivatives the aliphatic group is a linear or branched chain comprising from 8 to 22 carbon atoms, the said amine derivatives containing at least one anionic group, such as, for example, a carboxylate, sulfonate, sulfate, phosphate or phosphonate group.

Mention may in particular be made of (C8-C₂o)alkyl betaines, (C8-C₂o)alkyl sulfobetaines, (C8-C₂o)alkylamido(C3-C8)alkyl betaines and (C8-C₂o)alkylamido(C6-C8)alkyl sulfobetaines.

Mention may also be made, among the derivatives of optionally quaternized secondary or tertiary aliphatic amines which can be used, as defined above, of the compounds with the following respective structures (VI) and (VII):

Ra-CONHCH₂CH2-N⁺(Rb)(Rc)-CH₂COO- M⁺ X^" (VI) in which:

- R_a represents a Cio to C30 alkyl or alkenyl group derived from an acid R_aCOOH preferably present in hydrolysed coconut oil, or a heptyl, nonyl or undecyl group;

- Rb represents a β-hydroxyethyl group; and

- Rc represents a carboxymethyl group; - M⁺ represents a cationic counterion resulting from an alkali metal or alkaline earth metal, such as sodium, an ammonium ion or an ion resulting from an organic amine; and

- X^" represents an organic or inorganic anionic counterion, such as that chosen from halides, acetates, phosphates, nitrates, (C i -

C₄)alkyl sulfates and (C i -C₄)alkyl- or (C i -C₄)alkylarylsulfonates, in particular methyl sulfate and ethyl sulfate; or alternatively M⁺ and X^" are absent; Ra_'-C ONHCH2CH2-N(B)(B ') (VII) in which:

- B represents the -CH2CH2OX' group;

- B' represents the -(CH₂)_ZY' group, with z = 1 or 2;

- X^* represents the -CH2 C OOH, -CH2-COOZ ' , -CH2 CH2C O OH or -CH2CH2-COOZ ' group or a hydrogen atom;

- Y^* represents the -COOH, -COOZ ' or-CH₂CH(OH)S0₃ H group or the -CH₂CH(OH)S0₃-Z ' group;

- Z' represents a cationic counterion resulting from an alkali metal or alkaline earth metal, such as sodium, an ammonium ion or an ion resulting from an organic amine;

- R_a' represents a C 10 to C₃o alkyl or alkenyl group of an acid Ra'-COOH which is preferably present in hydro lysed linseed oil or coconut oil, or an alkyl group, in particular a C _{1 7} alkyl group, and its iso form, or an unsaturated C _{1 7} group .

These compounds are classified in the CTFA dictionary, 5^th edition, 1993 , under the names disodium cocoamphodiacetate, disodium lauroamphodiacetate, disodium capryloamphodiacetate, disodium capryloamphodiacetate, disodium cocoamphodipropionate, disodium lauroamphodipropionate, disodium caprylamphodipropionate, disodium capryloamphodipropionate, lauroamphodipropionic acid and cocoamphodipropionic acid. Mention may be made, by way of example, of the cocoamphodiacetate sold by Rhodia under the trade name Miranol^® C2M Concentrate.

Use may also be made of compounds of formula (VIII):

Ra"-NHCH(Yⁿ)-(CH2)nCONH(CH₂)n-N(Rd)(Re) (VIII) in which:

- Y" represents the -COOH, -COOZ" or -CH₂-CH(OH)S0₃H group or the CH₂CH(OH)S0₃-Z" group;

- Rd and R_e, independently of each other, represent a Ci to C₄ alkyl or hydroxyalkyl radical;

- Z" represents a cationic counterion resulting from an alkali metal or alkaline earth metal, such as sodium, an ammonium ion or an ion resulting from an organic amine;

- R_a" represents a Cio to C₃o alkyl or alkenyl group of an acid Ra"-COOH preferably present in hydrolysed linseed oil or coconut oil;

- n and n' denote, independently of each other, an integer ranging from 1 to 3.

Mention may be made, among the compounds of formula

(VIII), of the compound classified in the CTFA dictionary under the name sodium diethylaminopropyl cocoaspartamide and sold by Chimex under the name Chimexane HB.

These compounds can be used alone or as mixtures.

Use is preferably made, among the abovementioned amphoteric or zwitterionic surfactants, of (Cs-C₂o)alkyl betaines, such as coco betaine, (C8-C₂o)alkylamido(C₃-C8)alkyl betaines, such as cocamidopropyl betaine, and their mixtures, and the compounds of formula (VIII), such as the sodium salt of diethylaminopropyl laurylaminosuccinamate (INCI name: sodium diethylaminopropyl cocoaspartamide).

The content of the surfactant or surfactants, when they are present in the composition of the invention, preferably ranges from 0. 1 % to 50% by weight and more preferably from 0.5 % to 20% by weight, with respect to the total weight of the composition.

Preferably, the composition comprises one or more surfactants chosen from anionic surfactants and amphoteric or zwitterionic or non- ionic surfactants and/or their mixtures, better chosen from anionic surfactants and amphoteric or zwitterionic surfactants .

The non-ionic surfactants are preferably chosen from mono- or polyoxyalkylenated non-ionic surfactants, mono- or polyglycerolated non-ionic surfactants, alkylpolyglucosides and their mixtures.

The non-ionic surfactants are advantageously chosen from oxyethylenated (4 EO) sorbitan monolaurate, glyco l distearate, oxyethylenated (2 EO) lauryl alcohol, oxyethylenated (33 EO) cetearyl alcoho l and their mixtures.

Preferably, the anionic surfactants are chosen from (C₆- C₂₄)alkyl ether sulfates comprising from 2 to 50 ethylene oxide units .

Preferably, the amphoteric surfactants are chosen from (C₈ - C₂o)alkyl betaines .

According to a preferred embodiment, the composition comprises a mixture o f anionic and amphoteric or zwitterionic surfactants. More preferably, the surfactants o f the invention are anionic.

Cosmetically acceptable medium The composition o f the invention has to be cosmetically acceptable, namely contain a non-toxic cosmetically or physio lo gically acceptable medium capable o f being applied in particular to human hair and/or skin.

The cosmetically acceptable medium generally comprises at least water. d) additional organic solvent

According to a specific embodiment of the invention, the composition additionally comprises d) at least one additional organic so lvent, other than the liquid organic solvents exhibiting a value of the Hansen solubility parameter δΗ of less than 1 6 MPa^{1 /2}.

The choice is in particular made, as additional organic so lvent, of polar protic solvents, for example linear or branched C2 - C4 alkanols devoid o f aryl substituent, such as ethanol and isopropano l, glycerol, polyo ls, such as 1 ,3 -propanedio l or else 1 ,6-hexanedio l, and polyo l ethers, such as 2-butoxyethanol, propylene glyco l, dipropylene glyco l, propylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glyco l monomethyl ether, and their mixtures, preferably monohydroxylated C2 - C4 alkano ls, such as ethanol and isopropanol, more preferably ethanol.

The total content of the additional organic so lvent or so lvents, when they are present in the composition according to the invention, preferably ranges from 1 % to 40% by weight and more preferably from 5 % to 30% by weight, with respect to the total weight of the composition. e) the salts

According to a specific embodiment of the invention, the composition additionally comprises e) at least one salt o f acids and o f bases which are organic or inorganic, the salts being cosmetically acceptable.

In particular, the salts are chosen from those resulting from the addition between:

A) an organic or inorganic acid chosen from i) a halogen acid, such as hydrochloric acid HC1 or hydrobromic acid HBr, ii) sulfuric acid H2 S O4 , iii) a phosphorus-based acid, such as phosphoric acid, iv) alkylsulfonic acids : Alk-S(0)₂OH, such as methanesulfonic acid and ethanesulfonic acid; v) arylsulfonic acids : Ar-S(0)₂OH, such as benzenesulfonic acid and toluenesulfonic acid; vi) optionally hydroxylated carboxylic acids, such as acetic acid, succinic acid, tartaric acid or lactic acid, vii) alkoxysulfinic acids: Alk-0-S(0)OH, such as methoxysulfinic acid and ethoxysulfinic acid; viii) aryloxysulfinic acids, such as tolueneoxysulfinic acid and phenoxysulfinic acid; ix) triflic acid CF3SO3H and x) tetrafluoroboric acid HBF₄; and

B)an alkaline agent chosen from inorganic or organic or hybrid alkaline agents or their mixtures chosen from i) aqueous ammonia, ii) alkali metal carbonates or bicarbonates, such as sodium carbonate or potassium carbonate, iii) sodium bicarbonate or potassium bicarbonate, iv) alkali metal or alkaline earth metal hydroxides or their mixtures, v) organic alkaline agents, such as organic amines, i.e. which contain at least one substituted or unsubstituted amino group, such as alkanolamines, such as monoethanolamine, oxyethylenated and/or oxypropylenated ethylenediamines, amino acids and the compounds of following formula (1):

^R\ / ^RZ

N-W-N

R R ₍₁₎

in which formula (1):

· W is a divalent Ci-C₆ alkylene radical optionally substituted by a hydroxyl group or a Ci-C₆ alkyl radical and/or optionally interrupted by one or more heteroatoms, such as oxygen or NR^U;

• R^x, R^y, R^z, R⁴ and R^u, which are identical or different, represent a hydrogen atom or a Ci-C₆ alkyl, Ci-C₆ hydroxyalkyl or Ci- C₆ aminoalkyl radical;

vi) the amino acids which can be used are of natural or synthetic origin, in their L, D or racemic form, and comprise at least one acid functional group chosen more particularly from carboxylic acid, sulfonic acid, phosphonic acid or phosphoric acid functional groups. The amino acids can be in the neutral or ionic form.

Preferably, the salt or salts of the invention result from an inorganic acid and from an inorganic base. In particular, the salt or salts of the invention are chosen from those o f formula M⁺OH^" with M⁺ representing an alkali metal or alkaline earth metal, preferably an alkali metal, such as Na or K, more preferably K.

The total content o f the additional salt or salts, when they are present in the composition according to the invention, ranges in particular from 0. 1 % to 20% by weight, more particularly from 0.2% to 10%) by weight, preferably from 0.3 %> to 5 % by weight and more preferably from 0.4% to 1 % by weight, with respect to the total weight of the composition.

The additives

The composition according to the present invention can optionally additionally comprise one or more additives, different from the compounds o f the invention and among which mention may be made o f cationic, anionic, non-ionic or amphoteric polymers or their mixtures, anti-dandruff agents, anti-seborrhoeic agents, agents for combatting hair loss and/or for promoting hair regrowth, vitamins and provitamins, including panthenol, sunscreens, inorganic or organic pigments, sequestering agents, plasticizers, so lubilizing agents, inorganic or organic thickening agents, in particular polymeric thickening agents, opacifying or pearlescent agents, antioxidants, fragrances, preservatives, pigments and ceramides .

Of course, a person skilled in the art will take care to choose this or these optional additional compounds so that the advantageous properties intrinsically attached to the composition according to the invention are not, or not substantially, detrimentally affected by the envisaged addition or additions.

The above additives can in general be present in an amount, for each o f them, o f between 0%> and 20%> by weight, with respect to the total weight of the composition.

The composition according to the present invention can optionally additionally comprise one or more thickening agents and their mixtures. The total content of the organic thickening agent or agents, when they are present in the composition according to the invention, preferably ranges from 0.01 % to 20% by weight and more preferably from 0. 1 %) to 5 % by weight, with respect to the total weight of the composition.

Method

The method o f the invention is targeted at extracting or removing metal ions from keratinous fibres . This it because, during the life of keratinous fibres, the latter may end up charged with metal ions and in particular with metal cations .

According to a specific embodiment of the invention, the method makes it possible to extract the metal ions which correspond to metal cations, in particular po lyvalent metal cations.

Preferably, the metal cations extracted by the method of the invention are cations of alkali metals, alkaline earth metals or transition metals, in particular from Groups (Vllb), (VHIb), (lb), (lib) and (IVa) of the Perio dic Table of the Elements .

More preferably still, the cations o f metals extracted by the method of the invention are chosen from copper, iron, magnesium, manganese and calcium and in particular copper.

The method according to the invention comprises at least two successive stages consisting in app lying the composition as defined above to the keratinous fibres .

In other words, the composition is applied to the keratinous fibres on several occasions in succession, that is to say that the stages of application o f the composition according to the invention fo llow one another, with or without an intermediate rinsing stage.

Preferably, the method according to the invention invo lves a stage o f rinsing the keratinous fibres at least between two successive stages of application o f the composition.

The leave-on time o f the composition according to the invention on the keratinous fibres can vary between 1 to a few seconds and 1 hour, preferably between 1 0 seconds and 1 hour and more preferably still between 1 minute and 15 minutes .

The amount applied to the keratinous fibres is an amount which is effective in producing an effect on the type o f fibres used. This amount can generally vary from 0.01 to 10 grams o f composition per gram of hair, preferably from 0.05 to 5 grams .

The composition according to the invention can be applied to the hair, for example, using a comb , a fine brush, a broard brush or the fingers.

After at least two successive stages of application o f the composition, the keratinous fibres can be rinsed.

The rinsing is preferably carried out with water, more preferably still demineralized water.

The keratinous fibres can subsequently be superficially dried, washed using a standard shampoo and then dried.

According to a specific embodiment of the invention, the rinsing stage is fo llowed by a stage o f drying at ambient temperature or at a temperature of greater than 40°C .

Preferably, the hair is dried, in addition to supplying heat, with a flow o f air. This flow of air during the drying makes it possible to improve the individualization of the sheathing.

During the drying, a mechanical action can be exerted on the lo cks, such as combing, brushing or running the fingers through the hair.

The drying stage o f the method of the invention can be carried out with a hood dryer, a hair dryer or a straightening iron.

When the drying stage is carried out with a hood dryer or a hair dryer, the drying temperature is between 40°C and 1 10° C and preferably between 50°C and 90° C .

When the drying stage is carried out with a straightening iron, the drying temperature is between 1 10° C and 220° C and preferably between 130°C and 200°C .

In accordance with one embodiment, the method comprises at least two successive stages o f application of a composition according to the invention to the keratinous fibres, with an intermediate stage o f rinsing with water. At the end, a final rinsing completes the treatment.

Preferably, the composition is applied to natural keratinous fibres.

According to one embodiment, the composition according to the invention is applied to keratinous fibres which are naturally or artificially pigmented, particularly hair, the height of tone of which is greater than or equal to 6.

The notion o f "tone" is based on the classification of natural shades, one tone separating each shade from the shade immediately fo llowing or preceding it. This definition and the classification o f natural shades are well known to hairstyling professionals and are published in the publication " Science des traitements capillaires [Hair treatment science] " by Charles Zviak, 1988 , published by Masson, pages 215 and 278.

Preferably, the method according to the invention makes it possible to extract amounts o f metal ions at yields o f greater than 50%, better still greater than 60% and even better still greater than 70% .

Lightening method

Another subj ect-matter of the invention is a method for lightening keratinous fibres, in particular human keratinous fibres, such as the hair, comprising :

- at least two successive stages o f application o f a composition as defined above to the said fibres, and

- at least one stage of lightening the said keratinous fibres .

In an alternative form o f this method, the lightening stage occurs subsequently to the successive stages o f application o f the composition according to the invention.

In another alternative form o f this method, the lightening stage occurs prior to the successive stages of application o f the composition according to the invention. Finally, in another alternative form of this method, the lightening stage occurs between two successive stages o f application of the composition according to the invention.

In particular, the composition is applied on at least two occasions successively to keratinous fibres in order to prevent the breaking and/or undesirable lightening which occur fo llowing a method for lightening the fibres .

The composition thus makes it possible to limit the breaking and/or undesirable lightening brought about by the presence of at least one metal ion within the keratinous fibres, which occur after the implementation, on the said fibres, of a lightening method.

" Undesirable lightening" is understood to mean, within the meaning o f the present invention, an undesirable lightening which is boosted by the presence o f metal ions within the keratinous fibres and which occurs after a lightening treatment.

"To limit the breaking" is understood to mean, within the meaning o f the present invention, a limitation on the loss in weight of the keratinous fibres occurring after a lightening treatment. Dyeing method

The present invention also relates to a method for dyeing keratinous fibres, in particular human keratinous fibres such as the hair, comprising :

- at least two successive stages o f application o f a composition as defined above to the said fibres, and

- at least one stage of dyeing the said keratinous fibres .

In an alternative form o f this method, the dyeing stage occurs subsequently to the successive stages o f application of the composition according to the invention.

In another alternative form o f this method, the dyeing stage occurs prior to the successive stages of application o f the composition according to the invention. Finally, in another alternative form o f this method, the dyeing stage occurs between two successive stages o f application o f the composition according to the invention.

The dyeing stage corresponds to a dyeing method conventional in hair dyeing, which can be an oxidation dyeing, an oxidation dyeing catalysed by metal catalysts, a natural dyeing, for example with henna or indigo extracts, optionally mordanted with metal salts, a dyeing based on self-oxidizing dyes, such as based on dihydroxyindole, or a method for the direct dyeing of keratinous fibres .

The composition is applied on at least two occasions successively to keratinous fibres in order to prevent the change in co louring which occurs fo llowing a method for the dyeing o f keratinous fibres.

"Change in co louring" is understood to mean, within the meaning o f the present invention, an undesirable co louring which is boosted by the presence o f metal ions within the keratinous fibres and which occurs after a dyeing treatment.

The method preferably comprises a rinsing stage between the two successive stages o f application of the composition and the stage of dyeing the keratinous fibres .

The method for the treatment of keratinous fibres according to the invention is preferably carried out at a temperature of between 5 °C and 80° C, preferably between 10°C and 50°C, preferably at ambient temperature (25 °C) .

The fo llowing examp les are given by way of illustration o f the present invention.

EXAMPLES

In the examples which fo llow, all the amounts are shown as percentage by weight of active material, with respect to the total weight of the composition. In order to illustrate the effectiveness o f the compositions and methods according to the invention, the lo cks used were enriched in a standardized manner to contents o f copper o f approximately 1000 ppm. Example 1 : a) Composition tested

The fo llowing Composition (A) according to the invention was prepared from the ingredients, the contents of which are shown in the table below (% in g, unless otherwise mentioned) .

b) Mode of application of the composition

Locks o f Caucasian hair comprising 90% of natural white hairs (90NW) and permanent-waved white hairs (90PW) and also pigmented natural lo cks with a height o f tone o f 4 (HT4) and 8 (HT8) are enriched beforehand in copper to approximately 1000 ppm by immersion in a 0.394 millimo le per litre aqueous copper sulfate pentahydrate composition, each in a proportion of 400 ml per 1 0 locks , for 24 hours with agitation, and then the locks are superficially dried and dried with a hood dryer.

Composition (A) is then applied to the lo cks in a proportion o f 5 grams per gram of hair:

- 1 to 3 times with a leave-on time o f 15 minutes at a temperature of 27°C of Composition (A) at each application,

- or else 1 to 2 times with a leave-on time of one hour at a temperature of 27°C of Composition (A) at each application.

After each application of Composition (A) , the locks are rinsed and superficially dried and, in the end, they are washed using an Optimiseur anti-residue shampoo, rinsed and then dried with a hood dryer. c) Procedure for the calculation of the level of yield

The extraction yields are then calculated by assaying the metal ions before and after application of Composition (A) .

Tests such as described below are then carried out on the locks which have resulted in the best yields for extraction by Composition (A), in comparison with enriched locks which have not been treated with Composition (A) : Dyeing Tests by application o f an Inoa 7.45 dye to the lo cks of hair comprising 90% o f white hairs by ( 1 )/( 1 ) mixing with the Inoa

20 vo lumes oxidant, in a proportion o f 10 grams o f dye mixture per gram o f hair. The locks are left standing at 27°C for 35 minutes . On conclusion o f the leave-on time, the locks are rinsed, superficially dried and shampooed with an Inoa Post Color shampoo and then dried with a hood dryer. Lightening Tests by application o f a Majiblond 900 S lightening dye to the hair height of tone of 4 by ( l )/(2) mixing with the Inoa 30 vo lumes oxidant, in a proportion o f 10 grams o f dye mixture per gram of hair. The locks are left standing at 33°C for 50 minutes. On conclusion of the leave-on time, the locks are rinsed, superficially dried and shampooed with an Inoa Post Color shampoo and then dried with a hood dryer. Hair breaking tests by application of a Majiblond 900S lightening dye to the locks of hair having a height of tone of 4 by (l)/(2) mixing with the Inoa 40 volumes oxidant, in a proportion of 10 grams of dye mixture per gram of hair. The locks are left standing at 33°C for 50 minutes. On conclusion of the leave-on time, the locks are rinsed, superficially dried and shampooed with an Inoa Post Color shampoo and then dried with a hood dryer. A cycle of 5 applications is carried out.

The content of metal ion is analysed by spectrometry coupled to an argon plasma induced by high frequency (ICP-OES) after dissolution of the locks with nitric acid.

The lightening and the colouring obtained are measured using a Minolta CM-3600D spectrocolorimeter.

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

Δ E = (L* - L₀ *)² + (a* - a₀ *)² + (b* - b₀ *)²

(i)

In the equation (i), L*, a* and b* represent the values measured on locks of undyed hair and Lo*, ao* and bo* represent the values measured on locks of dyed hair.

Hair breaking is measured by weighing the lost hairs. d) Results The results are collated in the following tables .

The contents o f Cu (in ppm) within the hair before and after application(s) o f Composition (A) to locks o f hair comprising 90% o f natural white hairs and 90% o f permanent-waved white hairs are shown in the following tables .

1 ) Levels of yields for extraction of copper with regard to locks of hair comprising 90% of natural white hairs

2) Levels o f yields for extraction o f copper with regard to s o f hair comprising 90% of permanent-waved white hairs

90% white hairs permanent- waved

Content Extraction of Cu (ppm) yield reference non-enriched lock 21 . 15 - reference enriched lo ck 788 - lo ck treated by 1 application 93 %

Composition (A) 55.7

27°C (comparative)

lo ck treated by 2 applications

Composition (A)

97.4 88% left standing at 27°C for 15 minutes

(invention)

lo ck treated by 3 applications

Composition (A)

67.9 91 % left standing at 27°C for 15 minutes

(invention)

lo ck treated by 2 applications

Composition (A) 94%

44.5

left standing at 27°C for one hour

(invention)

3) Levels of yields for extraction of copper (after treatment for enriching in copper) and also other metal ions (for which no treatment for enriching with these ions was carried out) with regard to pigmented locks of hair HT 4

Content after

treating by 3

applications

Composition

Content Content (A)

before after left standing Extraction enriching in enriching at 27°C for 15 yield

copper in copper minutes

(invention)

with regard to

locks enriched

in copper

Ca 2633.0 2390.0 471.0 80.3%

Cu 22.2 1093.1 114.6 89.5%

Na 890.0 391.0 52.0 86.7%

Mg 542.0 366.0 93.0 74.6%

Zn 181.6 183.2 22.6 87.7%

K 40.0 57.0 24.0 57.9%

Sr 14.9 13.3 3.2 75.9%

Ba 8.9 9.0 7.7 14.2%

Mn 8.3 8.2 1.9 76.9%

Pb 5.8 5.7 1.2 79.9%

4) Levels of yields for extraction of copper (after treatment for enriching in copper) and also other metal ions (for which no treatment for enriching with these ions was carried out) with regard to pigmented locks of hair HT 8

Content after

treating by 3

applications

Composition (A)

Content Content

left standing at

before after Extraction

27°C for 15

enriching in enriching in yield minutes

copper copper

(invention) with

regard to locks

enriched in

copper

Ca 3650.0 2552.0 432.0 83.1%

Cu 21.1 1435.7 57.8 96.0%

Na 352.0 388.0 67.0 82.7%

Mg 424.0 228.0 61.0 73.2%

Zn 208.5 211.8 27.5 87.0%

K 50.0 44.0 29.0 34.1%

Fe 27.5 25.6 19.7 23.3%

Sr 17.6 12.1 4.4 63.4%

Ba 5.2 9.0 1.4 84.7%

Mn 4.0 3.1 1.0 66.8%

Pb 2.5 1.9 0.4 82.0%

Evaluation o f the change in the colouring

It is found that Composition (A) of the method of the invention makes it possible to significantly limit the change in the co lour brought about by the presence of copper in the hair, bringing it back to the level of colouring of hair non-enriched in copper.

In particular, it is observed that the pretreatment o f the lo cks using Composition (A) o f the method of the invention makes it possible to effectively limit the change in co louring brought about by the presence o f copper in the hair while resulting in a build-up o f the co louring similar to that observed for hair non-enriched in copper. 6) Evaluation o f the lightening

It is found that Composition (A) makes it possible to significantly limit the lightening o f the colour brought about by the presence of copper in the hair, bringing it back to the level of lightening of hair non-enriched in copper.

In particular, it is observed that the pretreatment o f the lo cks using Composition (A) makes it possible to effectively limit the lightening brought about by the presence o f copper in the hair while resulting in a build-up of the lightening similar to that observed for hair non-enriched in copper.

7) Evaluation o f the breaking of the hair

Loss of hair after (mg) with regard to a lock of natural hair HT 8 weighing 1 gram after 5 applications of superlighteners

It is found that Composition (A) makes it possible to significantly limit the breaking of the hair brought about by the presence of copper in the hair and observed after the application on five occasions of a lightening product.

In particular, the use in pretreatment of Composition (A) makes it possible to limit the lo ss of hair occurring after a lightening treatment on copper-containing hair.

Example 2 : a) Composition tested The fo llowing Composition (B) according to the invention was prepared from the ingredients, the contents of which are shown in the tables below (% in g, unless otherwise mentioned) .

A cycle o f 5 applications o f Composition (B) is then carried out in a proportion o f 4 grams per gram of hair on Caucasian hair comprising 90% o f natural white hairs doped beforehand with copper according to the same protocol as in Example 1 . Composition (B) is left standing at 27°C for 5 minutes each time.

The lo cks are rinsed and superficially dried each time. Finally, they are then dried with a hood dryer.

m nutes nvent on

Claims

1 . Method for the treatment of keratinous fibres, in particular human keratinous fibres, such as the hair, comprising at least two successive stages of application of a composition comprising :

a) one or more acids in a content of greater than or equal to 0.5 % by weight, with respect to the total weight of the composition, and

b) one or more liquid compounds having a value o f the Hansen so lubility parameter δΗ of less than 16 MPa^{1 /2}.

2. Method according to Claim 1 , characterized in that a) the acid or acids exhibit a pKa of less than 4.

3. Method according to Claim 1 or 2, characterized in that a) the acid or acids are organic acids having one or more carboxyl functional groups, such as those of fo llowing formula (I) :

in which formula (I) or one of its salts :

- A represents a saturated or unsaturated, cyclic or non-cyclic and aromatic or non-aromatic hydrocarbon group comprising from 1 to 50 carbon atoms which is monovalent when n has the value 0 or polyvalent when n is greater than or equal to 1 , which group is optionally interrupted by one or more heteroatoms and/or optionally substituted, in particular by one or more hydroxyl groups; preferably, A represents a monovalent (C i -C₆)alkyl group or a polyvalent (C i - C₆)alkylene group optionally substituted by one or more hydroxyl groups;

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

4. Method according to Claim 1 or 2, characterized in that a) the acid or acids are chosen from acetic acid, propanoic acid, butanoic acid, lactic acid, malic acid, glycolic acid, ascorbic acid, maleic acid, phthalic acid, succinic acid, taurine, tartaric acid, serine, arginine, glycine, glucuronic acid, gluconic acid, citric acid and their mixtures.

5. Method according to Claim 1 or 2, characterized in that a) the acid or acids are chosen from inorganic acids, in particular from phosphorus-based acids, such as phosphoric acid, halogen-based acids, such as hydrochloric acid, sulfur-based acids, such as sulfuric acid, and their mixtures.

6. Method according to Claim 1 or 2, characterized in that a) the acid or acids are chosen from organic acids having one or more carboxyl functional groups and inorganic acids.

7. Method according to any one of the preceding claims, characterized in that the pH of the acid composition applied ranges from 0.5 to 5, better still from 0.5 to 3 and even better still from 0.5 to 2.7.

8. Method according to any one of the preceding claims, characterized in that b) the liquid compound or compounds having a value of the Hansen solubility parameter δΗ of less than 16 MPa^1/2 are chosen from:

· alcohol ethers, in particular C1-C4 ethers of C5-C30 alcohols, which are preferably saturated, linear or branched, optionally interrupted by one or more non-adjacent ether functional groups;

• aliphatic esters of C1-C4 carboxylic acids and of mono- or polyhydroxylated C3-C10 alcohols, interrupted by one or more non- adjacent ether functional groups;

• aromatic ethers, in particular C₆-Cio aromatic ethers, of a Ci-C₆ alkyl optionally carrying a hydroxyl group,

• (C6-Cio)aryl(Ci-Ce)alkyl ethers of a Ci-C₆ alkyl optionally carrying a hydroxyl group,

· alkanols having aryl substituents, preferably for which the aryl part is a C₆-Cio aryl part, advantageously a C₆ aryl part, and the alkyl part of the alkanol is a C1-C4 alkyl part, it being possible for this alkyl part to be terminated or interrupted by a heteroatom, advantageously oxygen, or a hydroxyl group, preferably such as benzyl alcohol;

• lactones, preferably of formula (iii), and also their mixtures, with:

in which R' represents a hydrogen, a linear or branched Ci-Cs alkyl or a linear or branched C1-C4 hydroxyalkyl and n has the value 1, 2 or 3, and preferably R' represents a hydrogen, a linear or branched Ci-C₆ alkyl or a linear or branched C1-C2 hydroxyalkyl.

9. Method according to any one of the preceding claims, characterized in that b) the liquid compound or compounds having a value of the Hansen solubility parameter δΗ of less than 16 MPa^1/2 are chosen from alcohol ethers, aliphatic esters, aromatic ethers, alkanols having aryl substituents and their mixtures, preferably benzyl alcohol, phenylethanol and phenoxyethanol.

10. Method according to any one of the preceding claims, characterized in that the composition additionally comprises c) one or more surfactants chosen from anionic surfactants and amphoteric or zwitterionic surfactants and/or their mixtures; preferably, the surfactant or surfactants are anionic.

11. Method according to any one of the preceding claims, characterized in that the composition additionally comprises d) one or more additional solvents, other than the liquid organic solvents exhibiting a value of the Hansen solubility parameter δΗ of less than 16 MPa^1/2; in particular, the additional organic solvent or solvents are chosen from polar protic solvents, such as linear or branched C2-C4 alkanols devoid of aryl substituent, such as ethanol, propanol and isopropanol, glycerol, polyols, such as 1 ,3-propanediol or 1,6- hexanediol, and polyol ethers, such as 2-butoxyethanol, propylene glycol, dipropylene glycol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monomethyl ether, and their mixtures; preferably, the additional so lvent or solvents are chosen from monohydroxylated C2 - C4 alkanols, such as ethano l and isopropanol, more preferably ethanol.

12. Method according to any one o f the preceding claims, characterized in that the composition additionally comprises e) at least one salt o f organic or inorganic acids and bases, the salts being cosmetically acceptable; in particular, the salts are chosen from those resulting from the addition between:

A) an organic or inorganic acid chosen from i) a halogen acid, such as hydrochloric acid HC1 or hydrobromic acid HBr, ii) sulfuric acid H2 S O4 , iii) a phosphorus-based acid, such as phosphoric acid, iv) alkylsulfonic acids : Alk-S(0)₂OH, such as methanesulfonic acid and ethanesulfonic acid; v) arylsulfonic acids :

Ar-S(0)₂OH, such as benzenesulfonic acid and toluenesulfonic acid; vi) optionally hydroxylated carboxylic acids, such as acetic acid, succinic acid, tartaric acid or lactic acid, vii) alkoxysulfinic acids : Alk-0-S(0)OH, such as methoxysulfinic acid and ethoxysulfinic acid; viii) aryloxysulfinic acids, such as tolueneoxysulfinic acid and phenoxysulfinic acid; ix) triflic acid CF3 S O3H and x) tetrafluoroboric acid HBF₄ ; and

B) an alkaline agent chosen from inorganic or organic or hybrid alkaline agents or their mixtures chosen from i) aqueous ammonia, ii) alkali metal carbonates or bicarbonates, such as sodium carbonate or potassium carbonate, iii) sodium bicarbonate or potassium bicarbonate, iv) alkali metal or alkaline earth metal hydroxides or their mixtures, v) organic alkaline agents, such as organic amines, i. e. which contain at least one substituted or unsubstituted amino group, such as alkano lamines, such as monoethanolamine, oxyethylenated and/or oxypropylenated ethylenediamines, amino acids and the compounds o f fo llowing formula ( 1 ) :

FT

\

in which formula ( 1 ) : • W is a divalent Ci-C₆ alkylene radical optionally substituted by a hydroxyl group or a Ci-C₆ alkyl radical and/or optionally interrupted by one or more heteroatoms, such as oxygen or NRu;

• Rx, Ry, Rz, Rt and Ru, which are identical or different, represent a hydrogen atom or a Ci-C₆ alkyl, Ci-C₆ hydroxyalkyl or Ci-

C₆ aminoalkyl radical;

vi) the amino acids which can be used are of natural or synthetic origin, in their L, D or racemic form, and comprise at least one acid functional group chosen more particularly from carboxylic acid, sulfonic acid, phosphonic acid or phosphoric acid functional groups; preferably, the salt or salts of the invention result from an inorganic acid and from an inorganic base; more particularly, the salt or salts of the invention are chosen from those of formula M⁺OH^" with M+ representing an alkali metal or alkaline earth metal, preferably an alkali metal, such as Na or K, more preferably K.

13. Method according to any one of the preceding claims, which makes it possible to extract metal ions, in particular metal cations.

14. Method according to the preceding claim, characterized in that the metal cation is a cation of an alkali metal, alkaline earth metal or transition metal, preferably from Groups (Vllb), (Vlllb), (lb), (lib) and (IVa) of the Periodic Table of the Elements.

15. Method according to any one of the preceding claims, which makes it possible to extract copper from keratinous fibres.

16. Method according to any one of the preceding claims, characterized in that the keratinous fibres are natural.

17. Method for lightening keratinous fibres, in particular human keratinous fibres, such as the hair, comprising:

- at least two successive stages of application of a composition as defined according to any one of Claims 1 to 12 to the said fibres, and

- at least one stage of lightening the said keratinous fibres.

18. Method for dyeing keratinous fibres, in particular human keratinous fibres, such as the hair, comprising: - at least two successive stages o f application o f a composition as defined according to any one of Claims 1 to 12 to the said fibres, and

- at least one stage of dyeing the said keratinous fibres .