WO2018115258A1

WO2018115258A1 - Process for treating keratin materials using a composition comprising a compound of thiolactone type and a composition comprising an alkaline agent and/or an amino derivative of alkoxysilane

Info

Publication number: WO2018115258A1
Application number: PCT/EP2017/084044
Authority: WO
Inventors: Sébastien VOISIN; Nicolas Daubresse; Manon Chaumontet
Original assignee: L'oreal
Priority date: 2016-12-21
Filing date: 2017-12-21
Publication date: 2018-06-28
Also published as: FR3060341A1; FR3060341B1

Abstract

The present invention relates to a process for treating keratin materials, in particular the hair, using a first composition comprising one or more alkaline agents and/or one or more amino derivatives of alkoxysilane and a second composition comprising one or more compound(s) of thiolactone type.

Description

PROCESS FOR TREATING KERATIN MATERIALS USING A COMPOSITION COMPRISING A COMPOUND OF THIOLACTONE TYPE AND A COMPOSITION COMPRISING AN ALKALINE AGENT AND/OR AN AMINO DERIVATIVE OF

ALKOXYSILANE

The present invention relates to a process for treating keratin materials, in particular human keratin fibres, using a composition comprising at least one alkaline agent and/or at least one amino derivative of alkoxysilane and a composition comprising at least one compound of thiolactone type, in particular for shaping keratin fibres, and in particular for straightening/relaxing the hair.

In the hair field, consumers wish to have available compositions which make it possible to introduce a temporary change to their head of hair, while targeting good shape retention of the effect produced. In general, it is desired for the change to withstand shampooing for at least fifteen days or even more, depending on the nature of said change.

Heat treatments are generally used to modify the shape of the head of hair in a long-lasting manner. These treatments allow a visual modification of the appearance of the hairstyle, combining a decrease in the degree of frizziness, a reduction in overall volume of the head of hair, a decrease in little curls, a gain in manageability, a straighter overall appearance, a substantial gain in sheen, and a resistance to humidity and to heat in order to maintain the hairstyle throughout the day.

Moreover, this type of treatment has the advantage of facilitating the daily maintenance of the head of hair, with the use of fewer care products, in particular rinse- out care products such as hair conditioners or masks, or leave-in care products such as sera, care creams or balms, or taming mousses. Drying of the hair is facilitated, with a much shortened blow-drying time and a decrease in the daily use of flat irons, in terms both of time and intensity. This thus makes it possible to limit the risks of damaging the hair through combined factors of mechanical and thermal stress.

Several techniques are combined with these heat treatments. A first technique is based on the use of compositions based on thiol-based reducing agents. These techniques require strict adherence to the application conditions recommended by the suppliers, in particular in terms of amount and leave-in time. In addition, they may be contraindicated on hair that is too sensitized and may not be compatible with same-day application of other treatments, such as dyeing or bleaching operations. Moreover, they have an unpleasant smell.

Another technique is based on the use of compositions based on formol (or formaldehyde) and derivatives thereof. These treatments have the particular feature of being robust, perfectly compatible with all the other conventional hair treatments, such as the thiol-based straightening operations previously mentioned, alkaline relaxing operations, dyeing or bleaching operations of all types, performed before or after. They provide the hair with excellent manageability, a very bright sheen and easy daily care. However, in the event of repeated applications, further damage to the hair occurs, which can lead to breaking of the hairs. Furthermore, for toxicological reasons, the use of some of these compounds is now prohibited and/or regulated. It is therefore increasingly sought to avoid the use of such substances, which may prove to be aggressive to the hair and other keratin materials.

Another technique is based on the use of compositions based on acids, and most particularly on the use of glyoxylic acid. Patent application WO 201 1/104 282 thus proposed a novel process for semi-permanently straightening the hair, which consists in applying an a-keto acid solution to the hair for 15 to 120 minutes, then drying and, finally, straightening the head of hair with an iron at a temperature of about 200°C. The a-keto acid employed is preferably glyoxylic acid. However, it has been noted that glyoxylic acid may not be well tolerated, in particular when the scalp is sensitive and/or irritated. Its volatility, amplified by the use of heat from the iron, can also be a problem. Moreover, the prior art compositions can modify the hair and/or modify the colour thereof, and most particularly can cause unwanted changes in artificial colourings such as oxidation colours.

Treatments using a composition comprising a base combined with a heat treatment have also been proposed for straightening the hair. Such treatments make it possible to obtain good relaxing of curls, but can lead to impairment of the hair fibre. EP 1837010 especially describes a straightening/relaxing process using a composition comprising sodium hydroxide and a heat treatment. WO 2007/144707 describes a straightening/relaxing process using a composition comprising a non-hydroxylated base such as monoethanolamine or ethylenediamine, combined with a heat treatment. WO 2009/1 17344 also describes a straightening/relaxing process using a composition comprising a non-hydroxylated base and a protein-denaturing agent, combined with a heat treatment. In order to limit hair fibre impairment, it has also been proposed to use compositions comprising weak acids at alkaline pH, combined with a heat treatment. WO 2010/049434 describes, for example, a straightening/relaxing process in which a composition comprising a dicarboxylic acid, such as maleic acid, and a heat treatment are applied.

There is still a need to develop a process for treating keratin materials, in particular keratin fibres such as the hair, more particularly a process for shaping the hair, in particular straightening the hair, in a way that is efficient and long-lasting, while at the same time limiting degradation of the hair, in particular in a way that is persistent with respect to successive shampooing operations.

The applicant has now discovered that the use of a first composition comprising an alkaline agent and/or an amino derivative of alkoxysilane and of a second composition comprising at least one compound of thiolactone type makes it possible to achieve the desired long-lasting shaping properties.

Thus, a subject of the present invention is a process for treating keratin materials, in particular human keratin fibres such as the hair, using a first composition comprising one or more alkaline agents and/or one or more amino derivative(s) of alkoxysilane and a second composition comprising one or more compound(s) chosen from the compounds of formula (I) below:

(I)

and also the organic or mineral acid or base salts thereof, the optical isomers thereof, the geometrical isomers thereof, the tautomers thereof, and the solvates thereof such as hydrates;

in which formula (I):

• Y represents an oxygen or sulfur atom or a group NR with R representing a hydrogen atom or a (Ci-Ce)alkyl or hydroxy(Ci-Ce)alkyl group; preferably, Y represents an oxygen atom;

· Ri , R2, R3, R₄, R5 and R6, which may be identical or different, represent:

i) a hydrogen atom,

ii) hydroxyl,

iii) amino -NR'R", with R' and R", which may be identical or different, representing a hydrogen atom or a (Ci-Ce)alkyl or hydroxy(Ci-Ce)alkyl group;

iv) cyano,

v) -(Y')p-C(Y")-(Y'")_q-R₇ with R₇ representing a hydrogen atom or a (Ci-C₆)alkyl group, p and q, which may be identical or different, being equal to 0 or 1 , preferably with p+q = 0 or 1 , Y', Y" and Y"', which may be identical or different, representing an oxygen or sulfur atom, or NR with R as defined previously, preferably Y', Y" and Y'" represent an oxygen atom;

vi) optionally substituted (Ci-C6)alkyl, vii) optionally substituted (C2-C6)alkenyl,

viii) optionally substituted (Ci-C6)alkoxy,

preferably, said alkyl, alkenyl or alkoxy groups being optionally substituted with one or more groups chosen from hydroxyl and -(0)t-C(0)-Rs with t being equal to 0 or 1 , Rs represents a) a hydrogen atom, b) a hydroxyl group, c) (Ci-C6)alkyl, d) (Ci- C6)alkoxy, e) (di)(Ci-C6)(alkyl)amino, f) (di)hydroxy(Ci-C6)alkylamino;

or alternatively:

ix) Ri and R3 together form a covalent bond;

x) Ri and R2, and/or R3 and R₄, and/or R5 and R6 form, together with the carbon atom that bears them, a double bond oxo =0 or =C(Rg)-Rio with Rg and R10 representing a) a hydrogen atom or a group chosen from b) hydroxyl, c) (Ci-Ce)alkyl optionally substituted with one or more hydroxyl groups, and d) (C2-C6)alkenyl, e) - (Y')p-C(Y")-(Y'")_q-R₇ with Y', Y", Y"\ p, q and R₇ being as defined previously;

• n represents an integer between 0 and 6 inclusive, particularly between 0 and 4 inclusive, more particularly between 0 and 3 inclusive, preferably n is 1 or 2, and more preferentially n is 1 ; it being understood that:

- when n is greater than or equal to 2, then the contiguous groups C(Rs)-R6 may be identical or different.

The process of the invention makes it possible in particular to obtain good long- lasting relaxation of curls, in particular with respect to shampooing operations, while limiting the degradation of the hair. It also makes it possible to limit the formation of frizz in the presence of moisture.

Other characteristics and advantages of the invention will emerge more clearly on reading the description and the examples that follow.

In the following text, unless indicated otherwise:

■ the term "organic or mineral acid salt" is intended to mean cosmetically acceptable organic or mineral acid salts, more particularly the salts chosen from a salt derived from i) hydrochloric acid HCI, ii) hydrobromic acid HBr, iii) sulfuric acid H2SO4, iv) alkylsulfonic acids: Alk-S(0)20H such as methanesulfonic acid and ethanesulfonic acid; v) arylsulfonic acids: Ar-S(0)20H such as benzenesulfonic acid and toluenesulfonic acid; vi) citric acid; vii) succinic acid; viii) tartaric acid; ix) lactic acid; x) alkoxysulfinic acids: Alk-0-S(0)OH such as methoxysulfinic acid and ethoxysulfinic acid; xi) aryloxysulfinic acids such as tolueneoxysulfinic acid and phenoxysulfinic acid; xii) phosphoric acid H3PO4; xiii) acetic acid CH3C(0)OH; xiv) triflic acid CF3SO3H; and xv) tetrafluoroboric acid ^■ the term "alkyl" is intended to mean a linear or branched hydrocarbon-based radical containing from 1 to 8 carbon atoms, in particular from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms, for example methyl, ethyl, n-propyl, isopropyl, butyl, n-pentyl, n-hexyl, preferably methyl;

■ the term "alkenyl" is intended to mean a linear or branched hydrocarbon-based radical containing from 2 to 8 carbon atoms, in particular from 2 to 6 carbon atoms, preferably from 2 to 4 carbon atoms, and comprising at least one or more conjugated or non-conjugated unsaturations, such as ethylenyl, n-propylenyl, isopropylenyl, butylenyl, n-pentylenyl, n-hexylenyl;

" the term "alkox is intended to mean an alkyl oxy group with "alkyl" or "alkenyl" as defined previously;

^■ the term "optionally substituted' preceding alkyl, alkenyl or alkoxy groups is intended to mean that said groups may be substituted on the hydrocarbon-based radical with one or more groups, which may be identical or different, chosen from i) hydroxyl, ii) thiol, iii) halogen, iv) (Ci-C4)alkoxy, v) hydroxy(C2-C4)alkoxy; vi)

(di)hydroxy(Ci-C4)(alkyl)amino, vii) cyano, viii) nitro(so), ix) R_a-Z_a-C(Zb)-Z_c- and x) Ra-Z_a-S(0)t-Zc- with Zb representing an oxygen or sulfur atom or a group N R_a', Z_a and Zc, which may be identical or different, representing a bond, an oxygen or sulfur atom or a group NR_a; R_a representing a hydrogen atom or a (Ci-C4)alkyl group and R_a' representing a hydrogen atom or an alkyl group and t being 1 or 2;

^■ moreover, the addition salts that may be used in the context of the invention are especially chosen from salts of addition with a cosmetically acceptable base such as the basifying agents as defined below, for instance alkali metal hydroxides such as sodium hydroxide or potassium hydroxide, aqueous ammonia, amines or alkanolamines;

^■ the term "relaxing" includes, according to the invention, the relaxing, straightening or uncurling of Caucasian or African hair. The term "to relax" includes, according to the invention, the act of relaxing, straightening or uncurling of Caucasian or African hair;

■ the expression "at least one" is equivalent to "one or more"; and

^■ the expression "inclusive" for a range of concentrations means that the limits of the range are included in the defined interval.

The first composition used in the process according to the invention comprises one ore alkaline agent(s) and/or one or more amino derivative(s) of alkoxysilane.

The alkaline agent(s) can be chosen from: - hydroxides of alkali or alkaline-earth metals, preferably of lithium, of calcium, of sodium, of potassium buffered with one or more amino acids such as glycine,

- carbonates, bicarbonates or hydrogen carbonates, carbonates buffered with bicarbonate so as to obtain a pH < 12.0,

- phosphates of alkali or alkaline-earth metals, such as of lithium, of calcium, of sodium or of potassium,

- aqueous ammonia,

- alkanolamines such as mono-, di- and triethanolamines, mono-, di- and tri(hydroxymethyl)aminomethane and also derivatives thereof,

- amino acids,

- alkaline polyamino acids or alkaline poly(amino acid)s, such as polylysines, polyarginines,

- polyamines such as polyethyleneimines (PEIs), polyvinylamines, the compounds of formula (A) below:

R _v R_z

N - W - N

/ s

R R

y ' (A)

in which formula (A), W is a (Ci-Ce)alkylene group such as propylene optionally substituted with a hydroxyl or amino group or a C1-C4 alkyl radical; R_x, R_y, R_z and Rt, which may be identical or different, represent a hydrogen atom, or a C1-C4 alkyl or C1-C4 hydroxyalkyi radical.

By way of example of amines of formula (A), mention may be made of 1 ,3- diaminopropane, 1 ,3-diamino-2-propanol, spermine, and spermidine.

The term "alkanolamine" is intended to mean an organic amine comprising a primary, secondary or tertiary amine function, and one or more linear or branched C-i-Cs alkyl groups bearing one or more hydroxyl radicals.

Organic amines chosen from alkanolamines such as mono-, di- or trialkanolamines, comprising one to three C1-C4 hydroxyalkyi radicals, which may be identical or different, are in particular suitable for the implementation of the invention.

Among compounds of this type, mention may be made of monoethanolamine

(MEA), diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Ν,Ν-dimethylethanolamine, 2-amino-2-methyl-1-propanol, triisopropanolamine, 2- amino-2-methyl-1 ,3-propanediol, 3-amino-1 ,2-propanediol, 3-dimethylamino-1 ,2- propanediol and tris(hydroxymethylamino)methane.

More particularly, the amino acids that can be used are of natural or synthetic origin, in their L, D or racemic form, and comprise at least one acid function chosen more particularly from carboxylic, sulfonic, phosphonic or phosphoric acid functions. The amino acids can be in neutral or ionic form.

By way of amino acids that can be used in the present invention, mention may in particular be made of aspartic acid, glutamic acid, alanine, arginine, ornithine, citrulline, asparagine, carnitine, cysteine, glutamine, glycine, histidine, lysine, isoleucine, leucine, methionine, N-phenylalanine, proline, serine, taurine, threonine, tryptophan, tyrosine and valine.

Advantageously, the amino acids are basic amino acids comprising an additional amine function optionally included in a ring or in a ureido function.

Such basic amino acids are preferably chosen from those corresponding to formula

(B) below, and also the salts thereof

R-CH₂-CH(NH₂)-C(0)-OH (B)

in which formula (B), R represents a group chosen from: imidazolyle, preferably 5- imidazolyle; -(CH₂)₃-NH₂ ; -(CH₂)₂-NH₂; -(CH₂)₂N(H)-C(0)-NH₂; and -(CH₂)₂-N(H)-C(NH)- NH₂.

The compounds corresponding to formula (B) are histidine, lysine, arginine, ornithine and citrulline.

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

The term "poly"amines or "poly"(amino acid)s is intended to mean alkaline agents comprising at least two amino or amino acid groups linked to the same molecule; they are in particular polymers of which the backbone comprises or is substituted with one or more amine groups or amino acid groups.

The organic amine may also be chosen from amino acid dipeptides. By way of amino acid dipeptides that can be used in the present invention, mention may in particular be made of carnosine, anserine and balenine.

The organic amine may also be chosen from compounds comprising a guanidine function. By way of amines of this type that can be used in the present invention, mention may in particular be made of, in addition to the arginine already mentioned as amino acid, creatine, creatinine, 1 ,1 -dimethylguanidine, 1 ,1-diethylguanidine, glycocyamine, metformin, agmatine, N-amidinoalanine, 3-guanidinopropionic acid, 4-guanidinobutyric acid and 2-([amino(imino)methyl]amino)ethane-1-sulfonic acid.

By way of hybrid compounds, mention may be made of the salts of the amines previously mentioned, with acids such as carbonic acid or hydrochloric acid.

Use may in particular be made of guanidine carbonate or monoethanolamine hydrochloride. The amino derivative(s) of alkoxysilane can be chosen from the compounds corresponding to formula (C) below and/or the oligomers thereof and/or the hydrolysis products thereof:

RiSi(OR₂)z(R₃)x(OH)_y (C)

in which formula (C):

• Ri is a linear or branched, saturated or unsaturated, cyclic or acyclic, Ci- C6 hydrocarbon-based chain substituted with a group chosen from the following groups:

- amine NH2 or NHR (R = C1-C20, in particular C1-C6 alkyl optionally substituted with a radical comprising a silicon atom, C3-C40 cycloalkyl or C6-C30 aromatic),

- an aryl or aryloxy group substituted and/or interrupted with at least one amino group or with at least one C1-C4 aminoalkyl group;

Ri possibly being interrupted with a heteroatom (O, S, NH) or a carbonyl (CO) group;

• R2 and R3, which may be identical or different, represent a linear or branched alkyl group comprising from 1 to 6 carbon atoms,

• y denotes an integer ranging from 0 to 3, and

• z denotes an integer ranging from 0 to 3, and

· x denotes an integer ranging from 0 to 2,

with z+x+y=3.

The term "oligomer" is intended to mean the products of polymerization of the compounds of formula (C) comprising from 2 to 10 silicon atoms.

Preferably, R2 represents an alkyl group comprising from 1 to 4 carbon atoms, better still a linear alkyl group comprising from 1 to 4 carbon atoms, and preferably the ethyl group.

Preferably, R3 represents an alkyl group comprising from 1 to 4 carbon atoms, better still a linear alkyl group comprising from 1 to 4 carbon atoms, and preferably the methyl or ethyl groups.

Preferably, Ri is an acyclic chain.

Preferably, the compound of formula (C) comprises only one silicon atom in its structure.

Preferably, Ri represents an alkyl group, and even more preferentially a linear alkyl group, comprising from 1 to 6 carbon atoms, or a C1-C6 aminoalkyl group.

Preferably, z ranges from 1 to 3. Even more preferentially, z is equal to 3. Preferably, Ri is a linear or branched, saturated or unsaturated, C1-C6 hydrocarbon-based chain substituted with an amine group NH2 or NHR (R = C1-C20, in particular C1-C6 alkyl, C3-C40 cycloalkyl or C6-C30 aromatic).

Preferably, the first composition comprises at least one compound of formula (C) chosen from 3-aminopropyltriethoxysilane (APTES), 3-aminoethyltriethoxysilane (AETES), 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3- aminopropyltriethoxysilane, 3-(m-aminophenoxy)propyltrimethoxysilane, p- aminophenyltrimethoxysilane, N-(2-aminoethylaminomethyl)phenethyltrimethoxysilane, better still from 3-aminopropyltriethoxysilane (APTES), 3-aminoethyltriethoxysilane (AETES), 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3- aminopropyltriethoxysilane or the oligomers thereof and/or the hydrolysis products thereof.

According to one particularly preferred embodiment, the first composition comprises 3-aminopropyltriethoxysilane (APTES) or the oligomers thereof and/or the hydrolysis products thereof.

According to the invention, the alkaline agent(s) and/or the amino derivative(s) of alkoxysilane used is (are) present in the first composition preferably in a concentration of inclusively between 0.01 % and 40% by weight, preferentially between 0.1 % and 30%, better still between 1 % and 20% by weight relative to the total weight of the composition.

Preferentially, the first composition is aqueous.

According to one particular embodiment of the invention, the pH of the first composition according to the invention is basic, i.e. greater than or equal to 7.5.

According to one particular embodiment of the invention, the first composition of the invention has a pH ranging from 9.0 to 1 1 .0.

The pH values can be adjusted using an organic or mineral acid.

The composition can be buffered.

The term "organic acid" is intended to mean an acid, i.e. a compound that is capable of releasing a cation or proton H⁺ or H30⁺, in aqueous medium, which comprises at least one optionally unsaturated, linear or branched C1-C20 hydrocarbon-based chain, a (hetero)cycloalkyl or (hetero)aryl group and at least one acidic chemical function chosen in particular from carboxyl C(0)OH, sulfuric SO3H, SO2H, and phosphoric PO3H2,

More particularly, the acids used are chosen from hydrochloric acid HCI, hydrobromic acid HBr, sulfuric acid H2SO4, alkylsulfonic acids: (Ci-C6)Alk-S(0)20H such as methanesulfonic acid and ethanesulfonic acid; arylsulfonic acids: Ar-S(0)20H such as benzenesulfonic acid and toluenesulfonic acid; (Ci-C6)alkoxysulfinic acids: Alk- 0-S(0)OH such as methoxysulfinic acid and ethoxysulfinic acid; aryloxysulfinic acids such as tolueneoxysulfinic acid and phenoxysulfinic acid; phosphoric acid H3PO4; triflic acid CF3SO3H and tetrafluoroboric acid HBF4, and carboxylic acid(s) of formula (K) below:

in which formula (K) or a salt thereof:

A represents a saturated or unsaturated, cyclic or non-cyclic, and aromatic or non- aromatic hydrocarbon-based group, which is monovalent when t is 0 or polyvalent when t is greater than or equal to 1 , comprising from 1 to 50 carbon atoms, which is optionally interrupted with one or more heteroatoms and/or optionally substituted, especially with one or more hydroxyl groups; preferably, A represents a monovalent (Ci-Ce)alkyl group or a polyvalent (Ci-Ce)alkylene group optionally substituted with one or more hydroxyl groups.

Particularly, the carboxylic acid(s) of formula (K) as defined previously, and preferably the acid(s) used, is/are an alpha-hydroxy acid such as lactic acids, glycolic acids, tartaric acids or citric acids.

The second composition used in the process according to the invention comprises one or more compounds of formulae (I), of thiolactone type.

According to one particular embodiment of the invention, the compound(s) of formula (I) are such that n is 1 or 2, and referably of formula (la):

(la)

in which formula (la):

• Ri , R2, R3, R₄, R5 and R6, which may be identical or different, represent:

i) a hydrogen atom,

ii) hydroxyl,

iii) cyano, iv) amino -NR'R", R' and R", which may be identical or different, representing a hydrogen atom or a (Ci-Ce)alkyl or hydroxy(Ci-C6)alkyl group;

v) -(Y')_p-C(0)-(Y")q-R7 with R₇ representing a hydrogen atom or a (Ci-Ce)alkyl group, p and q, which may be identical or different, being equal to 0 or 1 , with Y' and Y", which may be identical or different, representing an oxygen atom or NR with R as defined previously, preferably with p+q = 0 or 1 ,

vi) (Ci-Ce)alkyl optionally substituted with one or more groups chosen from hydroxyl and -C(0)-Rs with Re representing a) a hydrogen atom, b) a hydroxyl group, c) (Ci-Ce)alkoxy,

vii) (C₂-C₆)alkenyl,

viii) (Ci-Ce)alkoxy,

or alternatively:

ix) Ri and R2, and/or R3 and R₄, and/or R5 and R6 form, together with the carbon atom that bears them, a double bond oxo =0 or =C(Rg)-Rio with Rg and R10 representing a) a hydrogen atom or a group chosen from b) hydroxyl, c) (Ci-

C₆)alkyl.

According to a particular embodiment of the invention, the compound(s) of formula (I) are such that n is 1 , and preferably

(I'a)

in which formula (I'a):

^• Ri , R2, R3, R₄, R5 and R6, which may be identical or different, are as defined previously, and in particular represent:

i) a hydrogen atom,

ii) hydroxyl,

iii) cyano,

iv) amino -NR'R", R' and R", which may be identical or different, representing a hydrogen atom or a (Ci-Ce)alkyl or hydroxy(Ci-Ce)alkyl group; v) -(Y')_p-C(0)-(0)q-R7 with R₇ representing a hydrogen atom or a (Ci-Ce)alkyl group, p and q, which may be identical or different, being equal to 0 or 1 , with Y' representing an oxygen atom or NR with R as defined previously, preferably with p+q = 0 or 1 , vi) optionally substituted (Ci-C6)alkyl,

vii) (C2-C6)alkenyl,

viii) (Ci-Ce)alkoxy,

said alkyl groups being optionally substituted with one or more groups chosen from hydroxyl and -(0)t-C(0)-Rs with t being equal to 0 or 1 , Re representing a) a hydrogen atom, b) a hydroxyl group, c) (Ci-C6)alkyl, d) (Ci-Ce)alkoxy, e) (di)(Ci- C6)(alkyl)amino, f) (di)hydroxy(Ci-C6)alkylamino;

or alternatively:

ix) Ri and R2, and/or R3 and R₄, and/or R5 and R6 form, together with the carbon atom that bears them, a double bond oxo =0 or =C(Rg)-Rio with Rg and R10 representing i) a hydrogen atom or a group chosen from ii) hydroxyl, iii) (Ci- Ce)alkyl optionally substituted with one or more hydroxyl groups, in particular, R3 and R₄ form, together with the oxygen atom, an oxo group and/or in particular, Ri and R2 represent, together with the carbon atom,

According to one particular embodiment of the invention, the compound(s) of formula (I) are such that n is 1 or 2, and is of formula (lb):

in which formula (lb):

^• R2, R₄, R5 and R6, which may be identical or different, represent:

i) a hydrogen atom,

ii) hydroxyl,

iii) cyano,

iv) amino -NR'R", R' and R", which may be identical or different, representing a hydrogen atom or a (Ci-Ce)alkyl or hydroxy(Ci-Ce)alkyl group; v) -(Y')_p-C(0)-(0)q-R7 with R₇ representing a hydrogen atom or a (Ci-Ce)alkyl group, p and q, which may be identical or different, being equal to 0 or 1 , with p + q = 0 or 1 , with Y' representing an oxygen atom or NR with R as defined previously, vi) (Ci-Ce)alkyl optionally substituted with one or more groups chosen from hydroxyl and -C(0)-Rs with Re representing a) a hydrogen atom, b) a hydroxyl group, c) (Ci-

C6)alkoxy,

vii) (C2-C6)alkenyl,

viii) (Ci-Ce)alkoxy,

or alternatively:

ix) R5 and R6 form, together with the carbon atom that bears them, a double bond oxo =0 or =C(Rg)-Rio with Rg and R10 representing a hydrogen atom or a (Ci-Ce)alkyl group.

According to one particular embodiment of the invention, the compound(s) of formula (I) are of formula (lc):

in which formula (lc):

R11 and R12, which may be identical or different, represent a hydrogen atom or a (Ci- Ce)alkyl group, such as methyl or ethyl. More preferentially, Rn and R12 represent a hydrogen atom.

According to one particular embodiment, the compounds of formula (I'c) are chosen from:

116 117 118 119

120 121 122

and also the organic or mineral base salts , the optical isomers, and the solvates such as hydrates.

According to a more particular embodiment of the invention, the compound(s) of formula (I) are of formula (I'a) or (lb) and n is 1.

More preferentially, the compounds of formula (I) of the invention are chosen from the following compounds:

6 8

17 18 19 20

265 266 267 and also the organic or mineral acid or base salts thereof, the optical isomers thereof, the geometrical isomers thereof, the tautomers thereof, and the solvates thereof such as hydrates.

Preferably, the compound(s) of formula (I) is (are) chosen from the compounds of formulae (38) to (122 and (153) to (258), preferably from the compounds of formulae (38) to (42b), (70) to (71 ), (86) to (87), (90) to (95), (153) to (163), more preferably from the compounds of formulae (38), (42a), (42b), (71 ), (82), (89), (107'), (153), (163).

The process for preparing the compound of formula (I'b) is defined according to the following synthesis scheme:

which consists in reacting, in step i), the 3-butene-1 ,2,3-tricarboxylic acid (A) with at least one molar equivalent of thioacetic acid, in particular in a non-protic organic solvent, which is preferably halogenated, such as dichloromethane, or ether of THF type, more particularly by heating the reaction medium up to the reflux of the solvent, preferably at a temperature of between 40°C and 80°C, so as to give the compound (B); in step ii), the compound (B) reacts with an organic or inorganic strong acid such as hydrochloric acid, in particular in a polar protic solvent such as water, more particularly by heating at the reflux of the solvent, preferably at a temperature between 60 and 90°C, so as to give the thiolactone (C).

According to a particular embodiment, the second composition comprises one or more compound(s) of formula (I) as defined previously, in an amount inclusively between 0.01 % and 50%, in particular between 0.1 % and 30%, more particularly between 1 % and 25%, preferentially between 2% and 20%, more preferentially between 5% and 15% by weight relative to the total weight of the second composition.

According to one particular embodiment of the invention, the second composition used in the process according to the invention also comprises a thiol-comprising reducing agent such as thioglycolic acid, or a non-thiol-comprising reducing agent.

Preferentially, the second composition used in the process according to the invention is aqueous.

Preferably, the second composition comprises water at a concentration ranging from 10% to 99.5%, better still from 30% to 95% and even better still from 40% to 90% by weight relative to the total weight of the second composition.

The pH of the second composition of the invention may be less than or equal to 7. Preferably, the pH of the composition ranges from 1 to 6 and more preferably from 2 to 6.

The pH values may be adjusted with an organic or mineral acid, as described previously, or with an alkaline agent chosen from mineral or organic or hybrid alkaline agents or mixtures thereof, as described previously. The first and second compositions used in the process according to the invention can also comprise at least one usual cosmetic ingredient, in particular chosen from surfactants, in particular non-ionic or cationic surfactants, solid or liquid fatty substances, thickeners, in particular polysaccharide thickeners, non-silicone cationic polymers, silicones, polar or non-polar solvents, sunscreens; moisturizers; antidandruff agents; antioxidants; chelating agents; pearlescent agents and opacifiers; plasticizers and coalescence agents; fillers; fragrances; silanes other than the amino derivatives of alkoxysilane; and crosslinking agents. The compositions can, of course, comprise several cosmetic ingredients appearing in the above list.

Depending on their nature and the purpose of the compositions, the usual cosmetic ingredients may be present in usual amounts, which can be readily determined by those skilled in the art and which may be, for each ingredient, between 0.01 % and 80% by weight. Those skilled in the art will take care to select the ingredients included in the composition, and also the amounts thereof, so that they do not harm the properties of the compositions of the present invention.

The compositions used in the process according to the invention may be in any formulation form conventionally used, and especially in the form of an aqueous, alcoholic or aqueous-alcoholic, or oily, solution or suspension; a solution or a dispersion of the lotion or serum type; an emulsion, in particular of liquid or semi-liquid consistency, of the O/W, W/O or multiple type; a suspension or emulsion of soft consistency of cream (O/W) or (W/O) type; an aqueous or anhydrous gel, or any other cosmetic form.

These compositions may be packaged in pump-action bottles or in aerosol containers, so as to apply the composition in vaporized (lacquer) form or in the form of a mousse. Such packaging forms are indicated, for example, when it is desired to obtain a spray or a mousse, for treating the hair. In these cases, the composition preferably comprises at least one propellant.

The compositions which have just been described can be applied to the hair. The bath ratio for the compositions applied, that is to say the amount by weight of composition applied relative to the weight of hair treated, can range from 0.1 to 10, more particularly from 0.2 to 5, and preferably is between 0.5 and 3. The term "bath ratio" is intended to mean the ratio between the total weight of the applied composition and the total weight of keratin fibres to be treated.

The first composition can be applied to the hair before, after or simultaneously with the second composition. Preferably, the first composition comprising one or more alkaline agents and/or one or more amino derivative(s) or alkoxysilane as described previously is applied to the hair before the second composition comprising at least one compound of formula (I) as described previously.

A step of rinsing the hair can be envisaged between the application of the two compositions.

According to one preferred embodiment, the first composition is applied before the second composition, with preferably a step of rinsing off the first composition before the application of the second composition.

The first and/or the second composition of the invention may be applied to dry or wet keratin materials, preferably to dry or wet hair, preferably to dry hair.

In particular, the step of applying each of the two compositions may be followed by a leave-on time. The leave-on time, namely the time of contact of the composition on the hair, is preferably at least 5 minutes, preferably between 10 and 60 minutes and preferably between 15 and 45 minutes. Rinsing of the hair may optionally be envisaged after the application of the last composition and optionally the leave-on time.

The hair may then optionally be wrung dry, preferably wrung dry.

The step of applying the compositions which has been described may be followed by a hair shaping step.

The shaping step can be a straightening/relaxing step or else a step for combing the hair.

This shaping step can be carried out by means of curlers, a curling iron or a straightening iron (also called flat tongs).

When the shaping step is carried out by means of an iron, it can be carried out at a temperature of at least 100°C.

Preferably, the iron is used at a temperature of at least 100°C, preferably at a temperature between, limits included, 100°C and 300°C, preferably between 120°C and 280°C, more preferably between 150°C and 250°C, and better still between 200 and 250°C.

According to one particular embodiment, a straightening iron is used. In this embodiment, the straightening with the straightening iron is performed in several passes on the hair, in general 3 to 10 passes.

According to a particular embodiment, the process of the invention comprising the steps of applying the compositions according to the invention to the hair, then of straightening with an iron, is performed one or more times, optionally separated by one or more cosmetic treatments, preferably a shampooing operation, until the desired shape or shape intensity is obtained. According to one particular embodiment of the invention, a composition comprising an oxidizing agent can be applied to the hair, after the shaping step. This oxidation step can be followed by rinsing of the hair.

According to a particular embodiment of the invention, the process for treating keratin materials of the invention does not include any thiol-based reducing agent such as thiolactic acid; preferably, the process does not include any reducing agent.

According to a particular embodiment, the process for treating keratin materials does not include a lanthionization step. The examples that follow serve to illustrate the invention without, however, being limiting in nature.

Examples The following compositions were prepared from the ingredients indicated in the tables below, all the amounts being indicated as per cent by weight of active material, relative to the total weight of the composition.

First compositions A1 to A3 according to the invention

Second composition B1 according to the invention

For each example, a lock of frizzy natural Caucasian hair of frizziness type IV, weighing 2.7 g having a length of 20 or 27 cm was treated in the following way: Processes P1 , P2, P3 and P4 according to the invention:

Process P1

The locks are wetted, a shampoo is applied (DOP camomille based on sodium laureth sulfate, on coco betaine, on glycerol and on cocamide MEA) in a proportion of 400 mg per lock. The locks are massaged and then rinsed with running water, wiped dry with a finger and dried with a hairdryer.

Composition A1 (2.7 g) is applied to a lock of dry hair (2.7 g). After 10 minutes, the lock is rinsed with running water (15 passes of 1 second followed by wiping dry between the fingers) and dried with a hairdryer. Composition B1 (2.7 g) is applied, and then, after 30 minutes, the lock is dried with a hairdryer (without blow drying) then straightened by means of ten passes of a flat iron with a pass speed of 10 cm.s^"1.

Process P2

Process P2 differs from process P1 in that the lock is straightened by means of ten passes of a flat iron with a pass speed of 13.5 cm.s^"1 (instead of 10 cm.s^"1).

Process P3

The locks are wetted, and a shampoo is applied (DOP camomile based on sodium laureth sulfate, on cocobetaine, on glycerol and on cocamide MEA) in a proportion of 400 mg per lock. The locks are massaged and then rinsed with running water, and wiped dry with a finger.

Composition A2 (2.7 g) is applied to a lock of wet hair (2.7 g). After 10 minutes, the lock is rinsed with running water (15 passes of 1 second followed by wiping dry between the fingers) and dried with a hairdryer. Composition B1 (2.7 g) is applied, and then, after 30 minutes, the lock is dried with a hairdryer (without blow drying) and then straightened by means of ten passes of a flat iron with a pass speed of 10 cm.s^-1.

Process P4

The locks are wetted, a shampoo is applied (DOP camomile based on sodium laureth sulfate, on cocobetaine, on glycerol and on cocamide MEA) in a proportion of 400 mg per lock. The locks are massaged, then rinsed with running water, and wiped dry with a finger.

Composition A3 (2.7 g) is applied to a lock of wet hair (2.7 g). After 10 minutes, the lock is rinsed with running water (15 passes of 1 second followed by wiping dry between the fingers) and dried with a hairdryer. Composition B1 (2.7 g) is applied, and then, after 30 minutes, the lock is dried with a hairdryer (without blow drying) then straightened by means of ten passes of a flat iron with a pass speed of 10 cm.s^"1.

Control processes T1 , T2, T3 and T4

Processes T1 and T2

Processes T1 and T2 differ respectively from processes P1 and P2 in that composition A1 is not applied, composition B1 being directly applied to dry hair.

Process T3

The locks are wetted, a shampoo is applied (DOP camomile based on sodium laureth sulfate, on cocobetaine, on glycerol and on cocamide MEA) in a proportion of 400 mg per lock. The locks are massaged, then rinsed with running water, wiped dry with a finger and dried with a hairdryer.

Composition A1 (2.7 g) is applied to a lock of dry hair (2.7 g). After 30 minutes, the lock is rinsed with running water (15 passes of 1 second followed by wiping dry between the fingers) and dried with a hairdryer. The lock is straightened by means of ten passes of a flat iron with a pass speed of 10 cm.s^"1.

Process T4

Composition A1 (2.7 g) is applied to a lock of dry hair (2.7 g). After 10 minutes, the lock is rinsed with running water (15 passes of 1 second followed by wiping dry between the fingers) and dried with a hairdryer. A composition C comprising 70% water and 30% ethanol (2.7 g) is applied, and then, after 30 minutes, the lock is dried with a hairdryer (without blow drying) then straightened by means of ten passes of a flat iron with a pass speed of 10 cm.s^"1.

Each lock is then evaluated according to two main criteria for an indication of the performance level of the straightening, in the time:

I - Level of relaxation after 1 shampooing operation and natural drying

II - Level of relaxation after 5 shampooing cycles and natural drying

The level of relaxation is evaluated using a set of reference locks, with the following grades: 1 : no relaxation

2: medium relaxation

3: good level of relaxation

4: very good level of relaxation

The results are as follows:

The process according to the invention thus makes it possible to improve the relaxation of curls, and to improve the persistence of the relaxation with respect to several shampooing operations.

Claims

1. - Process for treating keratin materials, in particular human keratin fibres such as the hair, using a first composition comprising one or more alkaline agents and/or one or more amino derivatives of alkoxysilane and a second composition comprising one or more compound(s) chosen from the compounds of formula I) below:

(I)

in which formula (I):

^• Ri , R2, R3, R₄, R5 and R6, which may be identical or different, represent:

i) a hydrogen atom,

ii) hydroxyl,

iv) cyano,

v) -(Y')p-C(Y")-(Y'")_q-R₇ with R₇ representing a hydrogen atom or a (Ci-C₆)alkyl group, p and q, which may be identical or different, being equal to 0 or 1 , Y', Y" and Y'", which may be identical or different, representing an oxygen or sulfur atom, or NR with R as defined previously, preferably Y', Y" and Y'" represent an oxygen atom,

vi) optionally substituted (Ci-C6)alkyl,

vii) optionally substituted (C2-C6)alkenyl,

viii) optionally substituted (Ci-Ce)alkoxy,

preferably, said alkyl, alkenyl or alkoxy groups being optionally substituted with one or more groups chosen from hydroxyl and -(0)t-C(0)-Rs with t being equal to 0 or 1 , Re represents a) a hydrogen atom, b) a hydroxyl group, c) (Ci-C6)alkyl, d) (Ci-C6)alkoxy, e) (di)(Ci-C6)(alkyl)amino, f) (di)hydroxy(Ci-C6)alkylamino; or alternatively:

ix) Ri and R3 together form a covalent bond;

x) Ri and R2, and/or R3 and R₄, and/or R5 and R6 form, together with the carbon atom that bears them, a double bond oxo =0 or =C(Rg)-Rio with Rg and R10 representing a) a hydrogen atom or a group chosen from b) hydroxyl, c) (Ci- Ce)alkyl optionally substituted with one or more hydroxyl groups, and d) (C2- C₆)alkenyl, e) -(Y')p-C(Y")-(Y'")_q-R₇ with Y', Y", Y'", p, q and R₇ being as defined previously;

• n represents an integer between 0 and 6 inclusive, particularly between 0 and 4 inclusive, more particularly between 0 and 3 inclusive, preferably n is 1 or 2, and more preferentially 1 ;

it being understood that:

2. - Process according to Claim 1 , in which the compound(s) of formula (I) are such that n is 1 or 2, and preferably of formula la):

(^la)

in which formula (la):

i) a hydrogen atom,

ii) hydroxyl,

iv) cyano, v) -(Y')_p-C(0)-(Y")q-R7 with R₇ representing a hydrogen atom or a (Ci-Ce)alkyl group, p and q, which may be identical or different, being equal to 0 or 1 , with Y' and Y", which may be identical or different, representing an oxygen atom or NR with R as defined previously, preferably with p+q = 0 or 1 ,

vii) (C2-C6)alkenyl,

viii) (Ci-Ce)alkoxy,

or alternatively:

ix) Ri and R2, and/or R3 and R₄, and/or R5 and R6 form, together with the carbon atom that bears them, a double bond oxo =0 or =C(Rg)-Rio with Rg and R10 representing a) a hydrogen atom or a group chosen from b) hydroxyl, c) (Ci- C₆)alkyl.

3. - Process according to either one of the preceding claims, in which the compound(s) of formula (I) are such that n is 1 , and of formula (I'a):

(I'a)

in which formula (I'b):

^• Ri , R2, R3, R₄, R5 and R6, which may be identical or different, are as defined in Claim 1 , and in particular represent:

i) a hydrogen atom,

ii) hydroxyl,

iii) amino -NR'R", with R' and R", which may be identical or different, representing a hydrogen atom or a (Ci-Ce)alkyl or hydroxy(Ci-Ce)alkyl group; iv) cyano,

v) -(Y')_p-C(0)-(0)q-R7 with R₇ representing a hydrogen atom or a (Ci-Ce)alkyl group, p and q, which may be identical or different, being equal to 0 or 1 , with p + q = 0 or 1 , with Y' representing an oxygen atom or NR with R as defined previously; vi) optionally substituted (Ci-C6)alkyl,

vii) (C2-C6)alkenyl,

viii) (Ci-Ce)alkoxy,

or alternatively:

ix) Ri and R2, and/or R3 and R₄, and/or R5 and R6 form, together with the carbon atom that bears them, a double bond oxo =0 or =C(Rg)-Rio with Rg and R10 representing i) a hydrogen atom or a group chosen from ii) hydroxyl, iii) (Ci- Ce)alkyl optionally substituted with one or more hydroxyl groups, in particular, R3 and R₄ form, together with the carbon atom, an oxo group and/or in particular, Ri and R2 represent, together with the carbon atom,

4. - Process according to either one of the preceding claims, in which the compound(s) of formula (I) are such that n is

in which formula (lc):

R11 and R12, which may be identical or different, represent a hydrogen atom or a (Ci- C6)alkyl group, such as methyl or ethyl; preferably Rn and R12 represent a hydrogen atom.

5. - Process according to Claim 1 , in which the compound(s) of formula (I) are such that n is 1 or 2, and of formula (lb):

(lb)

in which formula (lb):

^• R2, R₄, 5 and R6, which may be identical or different, represent:

i) a hydrogen atom,

ii) hydroxy I,

iii) amino -NR'R", R' and R", which may be identical or different, representing a hydrogen atom or a (Ci-Ce)alkyl or hydroxy(Ci-C6)alkyl group;

iv) cyano,

v) -(Y')_p-C(0)-(0)q-R7 with R₇ representing a hydrogen atom or a (Ci-Ce)alkyl group, p and q, which may be identical or different, being equal to 0 or 1 , with p + q = 0 or 1 , with Y' representing an oxygen atom or NR with R as defined previously, vi) (Ci-Ce)alkyl optionally substituted with one or more groups chosen from hydroxyl and -C(0)-Rs with Re representing a) a hydrogen atom, b) a hydroxyl group, c) (Ci-Ce)alkoxy,

vii) (C2-C6)alkenyl,

viii) (Ci-Ce)alkoxy,

or alternatively:

ix) R5 and R6 form, together with the carbon atom that bears them, a double bond oxo =0 or =C(Rg)-Rio with Rg and R10 represents a hydrogen atom or a (Ci- C6)alkyl group. 6. - Process according to any one of the preceding claims, in which the compound(s) of formula (I) are of formula (I'a) or (lb) and n is 1.

7. - Process according to any one of the preceding claims, in which the compound(s) of formula (I) are chosen from the following compounds:

114 114' 115 115'

169 170 171 172

265 266 267 and also the organic or mineral acid or base salts thereof, the optical isomers thereof, the geometrical isomers thereof, the tautomers thereof, and the solvates thereof such as hydrates. 8. - Process according to any one of the preceding claims, in which the compound(s) of formula (I) are chosen from the compounds of formulae (38) to (122) and (153) to (258), preferably from the compounds of formulae (38) to (42b), (70) to (71 ), (86) to (87), (90) to (95) and (153) to (163), more preferably from the compounds of formulae (38), (42a), (42b), (71 ), (82), (89), (107'), (153) and (163).

9. - Process according to any one of the preceding claims, in which the compound(s) of formula (I) is (are) in an amount inclusively between 0.01 % and 50%, in particular between 0.1 % and 30%, more particularly between 1 % and 25%, preferentially between 2% and 20%, more preferentially between 5% and 15% by weight relative to the total weight of the second composition.

10. - Process according to any one of the preceding claims, in which the pH of the second composition is less than or equal to 7, preferably ranges from 1 to 6, and more preferably from 2 to 6.

1 1 . - Process according to any one of the preceding claims, in which the second composition does not comprise any thiol-based reducing agents such as thiolactic acid, and preferably does not comprise any reducing agent. 12. - Process according to any one of the preceding claims, in which the first composition comprises an alkaline agent chosen from aqueous ammonia, hydroxides of alkali or alkaline-earth metals, such as of sodium or potassium, carbonates, phosphates of alkali or alkaline-earth metals, such as of sodium or potassium, alkanolamines such as mono-, di- and triethanolamines, mono-, di- and tri(hydroxymethyl)aminomethane and also the derivatives thereof, amino acids, alkaline polyamino acids, such as polylysines or polyarginines, polyamines such as polyethyleneimines (PEIs), polyvinylamines, the compounds of formula (A) below: R R

x\ /

N - W - N

R R

(A) in which formula (A), W is a (Ci-C6)alkylene group, such as propylene, optionally substituted with a hydroxyl or amino group or a C1-C4 alkyl radical; R_x, R_y, R_z and Rt, which may be identical or different, represent a hydrogen atom, or a C1-C4 alkyl or C1-C4 hydroxyalkyl radical.

13. - Process according to any one of the preceding claims, in which the first composition comprises one or more amino derivatives of alkoxysilane corresponding to formula (C) below and/or the oligomers thereof:

RiSi(OR₂)z(R₃)x(OH)_y (C)

in which formula (C)

• Ri is a linear or branched, saturated or unsaturated, cyclic or acyclic, C1-C6 hydrocarbon-based chain substituted with a group chosen from the following groups:

- amine N H2 or NHR (R = C1-C20, in particular C1-C6 alkyl, optionally substituted with a radical comprising a silicon atom, C3-C40 cycloalkyl or C6-C30 aromatic), - an aryl or aryloxy group substituted and/or interrupted with at least one amino group or with at least one C1-C4 aminoalkyl group;

Ri possibly being interrupted with a heteroatom (O, S, NH) or a carbonyl (CO) group,

• y denotes an integer ranging from 0 to 3, and

• z denotes an integer ranging from 0 to 3, and

· x denotes an integer ranging from 0 to 2,

with z+x+y=3.

14. - Process according to any one of the preceding claims, in which the first composition comprises at least one compound chosen from 3-aminopropyltriethoxysilane (APTES), 3-aminoethyltriethoxysilane (AETES), 3-aminopropylmethyldiethoxysilane, N-(2- aminoethyl)-3-aminopropyltriethoxysilane, 3-(m-aminophenoxy)propyltrimethoxysilane, p-aminophenyltrimethoxysilane, N-(2-aminoethylaminomethyl)phenethyltrimethoxy- silane, better still from 3-aminopropyltriethoxysilane (APTES), 3-aminoethyltriethoxy- silane (AETES), 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyl- triethoxysilane or the oligomers thereof and/or the hydrolysis products thereof. 15. - Process according to any one of the preceding claims, characterized in that the first composition comprises at least one compound chosen from 3-aminopropyltriethoxysilane and the oligomers thereof and/or the hydrolysis products thereof.

16. - Process according to any one of the preceding claims, in which the alkaline agent(s) and/or amino derivative(s) of alkoxysilane is (are) present in the first composition in a concentration of inclusively between 0.01 % and 40% by weight, preferentially between 0.1 % and 30%, better still between 1 % and 20% by weight relative to the total weight of the composition. 1 . - Process according to any one of the preceding claims, in which the first composition is applied to the keratin materials, in particular the hair, before, after or simultaneously with the second composition, preferably before the second composition.

18. - Process according to any one of the preceding claims, characterized in that the application of the first and second compositions to the hair is followed by a step of shaping the hair by means of a heat treatment at a temperature of at least 100°C, preferably by a straightening/relaxing step carried out by means of a straightening iron at a temperature of between, limits inclusive, 100°C and 300°C, preferably between 120°C and 280°C, more preferably between 150°C and 250°C, and even better still between 180°C and 230°C.