WO2024013110A1

WO2024013110A1 - Process for dyeing the hair comprising the application of a composition a comprising two alkoxysilanes, and the application of a composition b comprising a film-forming polymer

Info

Publication number: WO2024013110A1
Application number: PCT/EP2023/069073
Authority: WO
Inventors: Alexis LIARD; Arnaud Bonnamy
Original assignee: L'oreal
Priority date: 2022-07-11
Filing date: 2023-07-10
Publication date: 2024-01-18
Also published as: FR3137575A1

Abstract

A subject of the present invention is a process for dyeing keratin fibres such as the hair, comprising the application to the keratin fibres of at least one composition A comprising at least one alkoxy silane chosen from the compounds of formula (I) or of formula (I') and at least one alkoxysilane of formula (II), and the application to the keratin fibres of at least one composition B comprising at least one film-forming polymer. Said composition A and/or said composition B comprise at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I') or (II).

Description

Title: Process for dyeing the hair comprising the application of a composition A comprising two alkoxysilanes, and the application of a composition B comprising a filmforming polymer

Technical field of the invention

A subject of the present invention is a process for dyeing keratin fibres such as the hair, comprising the application to the keratin fibres of at least one composition A comprising at least one alkoxy silane chosen from the compounds of formula (I) or of formula (I’) and at least one alkoxysilane of formula (II), and the application to the keratin fibres of at least one composition B comprising at least one film-forming polymer. Said composition A and/or said composition B comprise at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II).

Context of the invention

In the field of dyeing keratin fibres, in particular human keratin fibres, it is already known practice to dye keratin fibres via various techniques using direct dyes or pigments for nonpermanent dyeing, or dye precursors for permanent dyeing.

There are essentially three types of process for dyeing the hair: a) “permanent” dyeing, the function of which is to afford a substantial modification to the natural colour and which uses oxidation dyes which penetrate into the hair fibre and forms the dye via an oxidative condensation process; b) non-permanent, semi-permanent or direct dyeing, which does not use the oxidative condensation process and withstands four or five shampoo washes; it consists in dyeing keratin fibres with dye compositions containing direct dyes; c) temporary dyeing, which gives rise to a modification of the natural colour of the hair that remains from one shampoo wash to the next, and which serves to enhance or correct a shade that has already been obtained. It may also be likened to a “makeup” process.

It is known practice to use pigments for this last type of dyeing. Specifically, the use of pigment at the surface of keratin fibres generally makes it possible to obtain visible colourings on dark hair, since the surface pigment masks the natural colour of the fibre.

However, the colourings obtained via this dyeing method exhibit the disadvantage of having poor resistance to shampooing operations and also to external agents, such as sebum, perspiration, brushing and/or rubbing actions. There is thus still a need for a process for dyeing keratin fibres, notably the hair, which has the advantage of obtaining a homogeneous and smooth coloured coating on the hair, while forming a coating that is persistent with respect to shampoo washing and to the various attacking factors to which the hair may be subjected such as brushing and/or rubbing actions, without degradation of the hair.

Thus, the aim of the present invention is to develop a process for dyeing keratin fibres, in particular the hair, which has the advantage of obtaining a homogeneous and smooth coloured coating on the hair, while forming a coating that is persistent with respect to shampoo washing and to the various attacking factors to which the hair may be subjected such as brushing and/or rubbing actions, without degradation of the hair.

The applicant has discovered, surprisingly, that all of these objectives can be achieved by means of the process according to the present invention.

Summary of the invention

A subject of the present invention is a process for dyeing keratin fibres such as the hair, comprising the following steps: a) applying to the keratin fibres at least one composition A comprising:

- at least one alkoxy silane chosen from the compounds of formula (I) or of formula (I’) as described below, oligomers thereof and/or mixtures thereof, and

- at least one alkoxy silane of formula (II) as described below, oligomers thereof and/or mixtures thereof, and b) applying to the keratin fibres at least one composition B comprising at least one film-forming polymer, composition A and/or composition B comprising at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described below.

The present invention also relates to a kit for dyeing keratin fibres such as the hair, comprising several compartments containing:

- in a first compartment, a composition A comprising:

- at least one alkoxy silane of formula (II) as described below, oligomers thereof and/or mixtures thereof,

- in a second compartment, a composition B according to the invention comprising at least one film-forming polymer, composition A and/or composition B comprising at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described below.

Through the use of this process, coloured coatings which are persistent with respect to shampoo washing and to the various attacking factors to which the hair may be subjected, such as blow- drying and perspiration, are obtained on the hair.

For the purposes of the present invention, the expression “pigment coating” means the presence of at least one alkoxysilane of formula (I), (I’) or (II) as described below, forming a coating on the surface of the pigment.

For the purposes of the present invention, the term “colouring that is persistent with respect to shampoo washing” means that the colouring obtained persists after a shampoo wash.

The expression “at least one” means one or more.

Unless otherwise indicated, the limits of a range of values are included in that range, notably in the expressions “between” and “ranging from ... to ...”.

The expression “keratin fibres” is understood particularly to mean human keratin fibres, such as the hair, eyelashes, eyebrows and body hair, preferentially the hair, eyebrows and eyelashes, more preferentially still the hair.

For the purposes of the present invention, the term “hair” means head hair. This term does not correspond to body hair, the eyebrows or the eyelashes.

For the purposes of the present invention, the term “silicone” denotes any organosilicon polymer or oligomer of linear or cyclic, branched or crosslinked structure, of variable molecular weight, obtained by polymerization and/or polycondensation of suitably functionalized silanes, and constituted essentially of a repetition of main units in which the silicon atoms are linked together via oxygen atoms (siloxane bond -Si-O-Si-), hydrocarbon-based radicals which are optionally substituted being directly linked via a carbon atom to said silicon atoms.

For the purposes of the present invention and unless otherwise indicated:

- an “alkyl” radical denotes a linear or branched saturated radical containing, for example, from 1 to 30 carbon atoms;

- an “aminoalkyl” radical denotes an alkyl radical as defined previously, said alkyl radical comprising an NFh group;

- a “hydroxyalkyl” radical denotes an alkyl radical as defined previously, said alkyl radical comprising an OH group;

- an “alkylene” radical denotes a linear or branched divalent saturated Ci-Cio hydrocarbonbased group such as methylene, ethylene or propylene; - a “cycloalky I" or “alicycloalkyi" radical denotes a cyclic saturated monocyclic or polycyclic, preferably monocyclic, hydrocarbon-based group comprising from 1 to 3 rings, preferably 2 rings, and comprising from 3 to 40 carbon atoms, in particular comprising from 3 to 24 carbon atoms, more particularly from 3 to 20 carbon atoms, even more particularly from 3 to 12 carbon atoms, preferably between 5 and 10 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl or norbornyl, or isobornyl, in particular cyclopropyl, cyclopentyl or cyclohexyl, it being understood that the cycloalkyl radical may be substituted with one or more (Ci-C4)alkyl groups such as methyl; preferably, the cycloalkyl radical is then an isobornyl group;

- an “aryl” radical is a monocyclic, bicyclic or tricyclic, fused or non-fused, unsaturated and aromatic hydrocarbon-based cyclic radical, comprising from 6 to 30 carbon atoms, preferably between 6 and 14 carbon atoms, more preferentially between 6 and 12 carbon atoms; preferably, the aryl group comprises 1 ring of 6 carbon atoms such as phenyl, naphthyl, anthryl, phenanthryl and biphenyl, it being understood that the aryl radical may be substituted with one or more (Ci- C4)alkyl groups such as methyl, preferably tolyl, xylyl, or methylnaphthyl; preferably, the aryl group represents a phenyl;

- an “aryloxy” radical denotes an aryl-oxy radical with “aryl” as defined previously;

- an “alkoxy” radical denotes an alkyl-oxy radical with “alkyl” as defined previously.

Unless otherwise indicated, when compounds are mentioned in the present patent application, this also includes the optical isomers thereof, the geometric isomers thereof, the tautomers thereof, the salts thereof, alone or as a mixture.

The invention is not limited to the examples illustrated. The characteristics of the various examples may notably be combined within variants which are not illustrated.

Detailed description of the invention

Process according to the invention

Composition A

Alkoxy silane of formula (I) or of formula (T):

Composition A according to the invention comprises at least one alkoxysilane chosen from the compounds of formula (I) or of formula (I’) below, oligomers thereof and/or mixtures thereof:

in which:

- Ra represents an alkyl group containing from 1 to 20 carbon atoms, preferably from 1 to 10 carbon atoms, more preferentially from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms such as a methyl, said alkyl group being optionally substituted with an aryl group; an alkoxy group containing from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms such as an ethoxy; or an aryl group containing from 6 to 12 carbon atoms;

- Rb and Rc, which may be identical or different, represent a hydrogen atom; an alkyl group containing from 1 to 20 carbon atoms, preferably from 1 to 6 carbon atoms and notably from 1 to 4 carbon atoms, notably an ethyl group, it being understood that if R_a does not represent an alkoxy group, then Rb and Rc cannot simultaneously represent a hydrogen atom;

- Rd and R_e, which may be identical or different, represent a hydrogen atom; an alkyl group containing from 1 to 20 carbon atoms, preferably from 1 to 6 carbon atoms and notably from 1 to 4 carbon atoms; a cycloalkyl group containing from 3 to 20 carbon atoms; an aryl group containing from 6 to 12 carbon atoms; an aminoalkyl group containing from 1 to 20 carbon atoms;

- A independently represents a linear or branched alkylene group containing from 1 to 10 carbon atoms, which may be interrupted with at least one heteroatom chosen from O, S, NH or a carbonyl group (CO), preferably NH;

- Q represents a carbonyl group (CO);

- r denotes an integer ranging from 0 to 1. Among the alkoxysilanes of formula (I), oligomers thereof and/or mixtures thereof, mention may notably be made of 3-aminopropyltriethoxysilane (APTES), 3- aminopropylmethyldiethoxysilane (APMDES), 3-ureidopropyltrimethoxysilane and N- cy clohexy laminomethy Itriethoxy silane .

APTES may be purchased, for example, from the company Dow Corning under the name Xiameter OFS-6011 Silane or from the company Momentive Performance Materials under the name Silsoft A-l 100 or from the company Shin-Etsu under the name KBE-903.

The compounds of formula (I) may also denote Dynasylan SIVO 210 or Dynasylan 1505 sold by the company Evonik.

3-Ureidopropyltrimethoxysilane may be purchased, for example, from the company Gelest under the reference SIU9058.0.

N-Cycloheylaminomethyltriethoxysilane may be purchased, for example, from the company Wacker under the name Geniosil XL 926.

Among the alkoxy silanes of formula (I’), oligomers thereof and/or mixtures thereof, mention may notably be made of N,N-bis[3-(trimethoxysilyl)propyl]ethylenediamine (CAS RN: 74956- 86-8), Nl,Nl-bis[3-(triethoxysilyl)propyl]-l,2-ethanediamine (CAS RN: 457065-96-2), 1,2- ethanediamine, Nl-[3-(triethoxysilyl)propyl]-Nl-[3-(trimethoxysilyl)propyl]- (CAS RN: 1638528-78-5), and mixtures thereof.

Preferably, the alkoxysilane(s), oligomers thereof and/or mixtures thereof are chosen from the compounds of formula (I) below:

in which:

- Ra represents an alkyl group containing from 1 to 10 carbon atoms, notably from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms, preferably a methyl, or an alkoxy group containing from 1 to 4 carbon atoms, preferably from 1 to 2 carbon atoms, preferably an ethoxy;

- Rb and Rc, which may be identical or different, represent an alkyl group containing from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms, such as an ethyl;

- Rd and Re, which are identical, represent a hydrogen atom or Rd denotes a hydrogen atom and R_e denotes a Cs-Ce cycloalkyl radical such as cyclohexyl; - A independently represents a linear or branched alkylene group containing from 1 to 10 carbon atoms, which may be interrupted with at least one heteroatom chosen from O, S and NH or a carbonyl group (CO), preferably NH;

- r denotes an integer equal to 0.

Preferably, the alkoxysilane(s), oligomers thereof and/or mixtures thereof are chosen from the compounds of formula (I) in which R_a represents an ethoxy group, Rb and Rc are identical and represent an ethyl, Rd and R_e represent a hydrogen atom, A represents a propylene and r denotes an integer equal to 0.

According to a preferred embodiment, the alkoxy silane of formula (I), oligomers thereof and/or mixtures thereof, is 3-aminopropyltriethoxysilane (APTES).

The alkoxy silane(s) of formula (I) or of formula (I’), oligomers thereof and/or mixtures thereof may be present in a total amount ranging from 0.1 to 40% by weight, preferably from 0.5 to 30% by weight, preferentially from 0.75 to 25% by weight, better still from 1 to 20% by weight and even better still from 1.5 to 15% by weight, relative to the total weight of composition A. These contents are separate from the content of the alkoxy silane of formula (I) or (I’) used for coating the pigment.

According to one preferred embodiment, the alkoxysilane(s) of formula (I), oligomers thereof and/or mixtures thereof is (are) present in a total amount ranging from 0.1 to 40% by weight, preferably from 0.5 to 30% by weight, preferentially from 0.75 to 25% by weight, better still from 1 to 20% by weight and even better still from 1.5 to 15% by weight, relative to the total weight of composition A.

Alkoxy silane of formula (II):

Composition A according to the invention comprises at least one alkoxysilane of formula (II) below, oligomers thereof and/or mixtures thereof:

(ID in which:

- Rb represents a hydrogen atom or an alkyl group containing from 1 to 20 carbon atoms, preferably from 1 to 6 carbon atoms and notably from 1 to 4 carbon atoms, notably an ethyl group;

- Rc represents an alkyl group containing from 1 to 20 carbon atoms, preferably from 1 to 10 carbon atoms, more preferentially from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms such as a methyl, said alkyl group being optionally substituted with an aryl group; an alkoxy group containing from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms such as an ethoxy; or an aryl group containing from 6 to 12 carbon atoms; it being understood that if R_a and Rc do not represent an alkoxy group, then Rb cannot represent a hydrogen atom;

- k denotes an integer ranging from 0 to 5, preferably ranging from 0 to 3;

- Rf represents a hydrogen atom; an alkyl group containing from 1 to 10 carbon atoms and notably from 1 to 4 carbon atoms; or a group of formula (Ila) below:

in which R_n represents a hydroxyl group (OH); an alkyl group containing from 1 to 10 carbon atoms, preferably a methyl.

Among the alkoxysilanes of formula (II), oligomers thereof and/or mixtures thereof, mention may notably be made of tetraethoxy silane (TEOS), methyltrimethoxy silane (MTMS), methyltriethoxysilane (MTES), dimethyldiethoxysilane (DMDES), diethyldiethoxysilane, dipropyldiethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane, phenyltriethoxysilane, phenylmethyldiethoxysilane, diphenyldiethoxysilane, benzyltriethoxysilane, benzylmethyldiethoxysilane, dibenzyldiethoxysilane, acetoxymethyltriethoxysilane and mixtures thereof.

TEOS may be purchased, for example, from the company Evonik under the name Dynasylan® A or Dynasylan® A SQ.

MTES may be purchased, for example, from the company Evonik under the name Dynasylan® MTES. DMDES may be purchased, for example, from the company Gelest under the reference SID3404.0.

Preferably, the alkoxysilane(s) of formula (II), oligomers thereof and/or mixtures thereof are such that:

- Ra represents an alkoxy group containing from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms such as a methoxy or an ethoxy; or an alkyl group containing from 1 to 10 carbon atoms optionally substituted with an aryl group, preferably 1 to 2 carbon atoms optionally substituted with an aryl group;

- Rb represents an alkyl group containing from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms, in particular from 1 to 2 carbon atoms, such as a methyl or an ethyl;

- Rc represents an alkoxy group containing from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms, such as a methoxy or an ethoxy;

- k denotes an integer ranging from 0 to 3, preferably equal to 0;

- Rf represents a hydrogen atom or an alkyl group containing from 1 to 10 carbon atoms and notably from 1 to 4 carbon atoms, such as a methyl or an ethyl.

More preferentially, the alkoxysilane(s) of formula (II), oligomers thereof and/or mixtures thereof are such that:

- Ra represents an alkyl group containing from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms, in particular from 1 to 2 carbon atoms, such as a methyl or an ethyl;

- k denotes an integer equal to 0;

- Rf represents an alkyl group containing from 1 to 10 carbon atoms and notably from 1 to 4 carbon atoms, such as a methyl or an ethyl.

According to a preferred embodiment, the alkoxysilane of formula (II), oligomers thereof and/or mixtures thereof, is methyltrimethoxysilane (MTMS) or methyltriethoxysilane (MTES). The alkoxysilane(s) of formula (II), oligomers thereof and/or mixtures thereof may be present in a total amount ranging from 0.5 to 90% by weight, preferably from 1 to 75%, preferentially from 3 to 45% by weight, better still from 5 to 40% by weight, relative to the total weight of composition A.

These contents are separate from the content of the alkoxysilane of formula (lib) used for coating the pigment. Organic solvents:

Composition A according to the invention may comprise one or more organic solvents.

Examples of organic solvents that may be mentioned include C1-C4 lower alkanols, such as ethanol and isopropanol; polyols and polyol ethers, for instance glycerol, 2-butoxyethanol, propylene glycol, propylene glycol monomethyl ether and diethylene glycol monoethyl ether and monomethyl ether, and also aromatic alcohols, for instance benzyl alcohol or phenoxyethanol, and mixtures thereof.

Preferably, composition A according to the invention comprises ethanol.

The organic solvent(s) may be present in a total amount ranging from 1 to 70% by weight, preferably from 5 to 55% by weight, more preferentially from 10 to 50% by weight, relative to the total weight of composition A according to the invention.

Composition B:

Film-forming polymer:

Composition B according to the invention comprises at least one film-forming polymer.

Preferably, the film-forming polymer(s) are chosen from hydrophilic film-forming polymers, hydrophobic film-forming polymers, and mixtures thereof.

For the purposes of the invention, the term “polymed’ means a compound corresponding to the repetition of one or more units (these units being derived from compounds known as monomers). This or these unit(s) are repeated at least twice and preferably at least three times. The term “hydrophobic polymer” is intended to mean a polymer having a solubility in water at 25°C of less than 1% by weight.

The term “hydrophilic polymer” is intended to mean a polymer having a solubility in water at 25°C of greater than or equal to 1% by weight.

The term “film-forming” polymer is intended to mean a polymer that is capable of forming, by itself or in the presence of an auxiliary film-forming agent, a macroscopically continuous film on a support, notably on keratin materials, and preferably a cohesive film.

According to a preferred embodiment, the film-forming polymer(s) are chosen from hydrophobic film-forming polymers.

In a particularly preferred embodiment, the hydrophobic film-forming polymer is a polymer chosen from the group comprising: film-forming polymers that are soluble in an organic solvent medium, in particular liposoluble polymers; this means that the polymer is soluble or miscible in the organic medium and forms a single homogeneous phase when it is incorporated into the medium; film-forming polymers that are dispersible in an organic solvent medium, which means that the polymer forms an insoluble phase in the organic medium, the polymer remaining stable and/or compatible once incorporated into this medium. In particular, such polymers may be in the form of non-aqueous dispersions of polymer particles, preferably dispersions in silicone oils or hydrocarbon-based oils; in one embodiment, the non-aqueous polymer dispersions comprise polymer particles stabilized on their surface with at least one stabilizer; these non-aqueous dispersions are often referred to as NADs; film-forming polymers in the form of aqueous dispersions of polymer particles, which means that the polymer forms an insoluble phase in water, the polymer remaining stable and/or compatible once incorporated into the water, the polymer particles possibly being stabilized on their surface with at least one stabilizer. These polymer particles are often referred to as latexes; in this case, the composition must comprise an aqueous phase.

Among the hydrophobic film-forming polymers that may be used in the composition of the present invention, mention may be made of synthetic polymers, of radical type or of polycondensate type, polymers of natural origin, and mixtures thereof.

Hydrophobic film-forming polymers that may be mentioned in particular include acrylic polymers, polyurethanes, polyesters, polyamides, polyureas, cellulose-based polymers such as nitrocellulose, silicone polymers, polymers of acrylamide type, and polyisoprenes.

Non-ionic, amphoteric, anionic or cationic hydrophobic film-forming polymers may be used. Preferably, the hydrophobic film-forming polymer(s) according to the invention are chosen from acrylic acid copolymers, methacrylic acid copolymers, acrylic acid ester homopolymers or copolymers, methacrylic acid ester homopolymers or copolymers, acrylic acid amide homopolymers or copolymers, methacrylic acid amide homopolymers or copolymers, vinylpyrrolidone copolymers, vinyl alcohol copolymers, vinyl acetate copolymers, ethylene homopolymers or copolymers, propylene homopolymers or copolymers, styrene homopolymers or copolymers, polyurethanes, polyesters and/or polyamides.

The hydrophobic film-forming polymer can be chosen from homopolymers and copolymers of olefins such as cyclic olefins; of butadiene; of isoprene; of styrene; of vinyl ethers, esters or amides; of (meth)acrylic acid esters or amides containing a linear, branched or cyclic C1-C20 alkyl group, a Ce-Cio aryl group or a C2-C6 hydroxyalkyl group. The hydrophobic film-forming polymer may notably be chosen from homopolymers and copolymers which may be obtained from monomers chosen from the group constituted of isooctyl (meth)acrylate, isononyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, isopentyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, ethyl (meth)acrylate, methyl (meth)acrylate, tert-butyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, benzyl acrylate and phenyl acrylate, or mixtures thereof.

Mention may be made, for example, of the ethylene/sodium acrylate copolymer sold under the trade name Ecosmooth Satin® by the company Dow.

The hydrophobic film-forming polymer may notably be chosen from the homopolymers and copolymers that may be obtained from amides of acid monomers; mention may be made of (meth)acrylamides, and notably N-alkyl(meth)acrylamides, in particular of C2-C12 alkyl, such as N-ethylacrylamide, N-t-butylacrylamide or N-octylacrylamide; N-(Ci- C4)dialkyl(meth)acrylamides and perfluoroalkyl (meth)acrylates.

Mention may also be made of the copolymers of which the CTFA (4th Ed., 1991) name is Octylacrylamide/Acrylates/Butylaminoethyl Methacrylate Copolymer, such as the products sold under the name Amphomer® or Lovocryl® 47 by the company National Starch, and also the copolymers with the CTFA name Acrylate s/Octylacrylamide Copolymer, such as the products sold under the name Dermacryl® LT or Dermacryl® 79 by the company National Starch.

According to a preferred embodiment, the hydrophobic film-forming polymer(s) according to the invention are chosen from anionic copolymers.

Preferably, the anionic copolymers according to the invention are copolymers of acrylic acid, of methacrylic acid or of (meth)acrylic acid esters containing a linear, branched or cyclic Ci-Ce alkyl group, as described under the INCI name Acrylates.

Such copolymers are sold by the company Dow Chemical under the name Aculyn®33. Copolymers of unsaturated ethylenic acid esters of alkoxylated fatty alcohols may also be used according to the invention. Such unsaturated ethylenic acid esters are in particular of acrylic acid, methacrylic acid and itaconic acid, and such alkoxylated fatty alcohols are in particular steareth-20 and ceteth-20.

Mention will be made for example of Aculyn®22 (Acrylates/Steareth-20 Methacrylate Copolymer), Aculyn®28 (Acrylates/Beheneth-25 Methacrylate Copolymer), Structure 2001® (Acrylates/Steareth-20 Itaconate Copolymer), Structure 3001® (Acrylates/Ceteth-20 Itaconate Copolymer), Structure Plus® (Acrylates/ Aminoacrylates/C 10-30 Alkyl PEG-20 Itaconate Copolymer), Carbopol® 1342, 1382, Ultrez 20, Ultrez 21 (Acrylates/C 10-30 Alkyl Acrylate Crosspolymer), Synthalen W2000® (Acrylates/Palmeth-25 Acrylate Copolymer) or Soltex OPT (Acrylates/Ci2-22 Alkyl Methacrylate Copolymer) sold by the company Dow Chemical. The hydrophobic film-forming polymer may also be chosen from homopolymers and copolymers obtained from vinyl monomers. Mention may be made of homopolymers or copolymers of N-vinylpyrrolidone, vinylcaprolactam, vinyl-N-(Cl-C6)alkylpyrroles, vinyloxazoles, vinylthiazoles, vinylpyrimidines or vinylimidazoles.

As examples of vinylpyrrolidone copolymers that may be used in the invention, mention may be made of the VP/vinyl laurate copolymer, the VP/vinyl stearate copolymer, the butylated polyvinylpyrrolidone (PVP) copolymer, the VP/hexadecene copolymer sold by ISP under the name Ganex V216, the VP/eicosene copolymer sold by ISP under the name Ganex V220, the VP/triacontene copolymer or the VP/acrylic acid/lauryl methacrylate copolymer.

The hydrophobic film-forming polymer may also be chosen from homopolymers and copolymers that may be obtained from olefins such as ethylene, propylene, butenes, isoprene, butadienes.

In one embodiment, the hydrophobic film-forming polymer according to the invention is a block copolymer comprising at least one block constituted of styrene units or styrene derivatives (for example methylstyrene, chlorostyrene or chloromethylstyrene). The copolymer comprising at least one styrene block may be a diblock or triblock copolymer, or even a multiblock, star or radial copolymer. The copolymer comprising at least one styrene block may also comprise, for example, an alkylstyrene (AS) block, an ethylene/butylene (EB) block, an ethylene/propylene (EP) block, a butadiene (B) block, an isoprene (I) block, an acrylate (A) block or a methacrylate (MA) block, or a combination of these blocks. The copolymer comprising at least one block constituted of styrene units or styrene derivatives can be a diblock or triblock copolymer, and in particular of the polystyrene/polyisoprene or polystyrene/polybutadiene type, such as those sold or manufactured under the name Luvitol HSB by BASF SE.

Preferably, the hydrophobic film-forming polymer(s) according to the invention are chosen from vinylpyrrolidone (co)polymers, vinyl alcohol (co)polymers, vinyl acetate (co)polymers, carboxyvinyl (co)polymers, acrylic acid (co)polymers, methacrylic acid (co)polymers, acrylic acid ester (co)polymers, ethylene (co)polymers, acrylamide (co)polymers and mixtures thereof. More preferentially, the hydrophobic film-forming polymer(s) are chosen from polyvinylpyrrolidone copolymers, acrylamide copolymers, acrylic acid ester homopolymers or copolymers, ethylene homopolymers or copolymers and mixtures thereof. According to another preferred embodiment, the film-forming polymer(s) are chosen from hydrophilic film-forming polymers.

Non-ionic, anionic or cationic hydrophilic film-forming polymers may be used.

The hydrophilic film-forming polymer may be chosen from vinylpyrrolidone (co)polymers, vinyl alcohol (co)polymers, vinyl acetate polymers, carboxyvinyl (co)polymers, acrylic acid (co)polymers, methacrylic acid (co)polymers, natural gums, polysaccharides and/or acrylamide (co)polymers.

Preferably, the hydrophilic film-forming polymer is chosen from vinylpyrrolidone homopolymers (PVP) and/or vinylpyrrolidone copolymers, more preferentially vinylpyrrolidone homopolymers (PVP).

Examples that may be mentioned include the vinylpyrrolidone homopolymers (PVP) sold under the name Luviskol® K by the company BASF SE, in particular Luviskol® K 90 or Luviskol® K 85 by the company BASF SE.

The polymer PVP K30 sold by the company Ashland Inc. (ISP, POI Chemical) may also be used. PVP K30 is a polyvinylpyrrolidone polymer that is soluble in cold water, having the CAS number 9003-39-8 and a molecular weight of 40000 g/mol.

Other vinylpyrrolidone homopolymers suitable for the invention are sold under the trade name Luvitec K 17, Luvitec K 30, Luvitec K 60, Luvitec K 80, Luvitec K 85, Luvitec K 90 and Luvitec K 115 by the company BASF SE.

Mention may also be made of the vinylpyrrolidone/vinyl ester copolymers sold under the name Luviskol® by the company BASF SE, in particular the non-ionic polymers Luviskol® VA64 and Luviskol® VA73 (vinylpyrrolidone/vinyl acetate copolymers).

Mention may also be made of styrene/vinylpyrrolidone copolymers, vinylpyrrolidone/vinyl acetate copolymers, vinylpyrrolidone/DMAPA acrylates copolymers and vinylpyrrolidone/vinylcaprolactam/DMAPA acrylates copolymers.

Vinylpyrrolidone/vinylcaprolactam/DMAPA acrylates copolymers may be sold by the company Ashland Inc. under the trade name Aquaflex® SF-40.

The vinylpyrrolidone/DMAPA acrylates copolymers may be sold by the company Ashland Inc. under the trade name Styleze CC-10.

As vinylpyrrolidone copolymers, mention may be made of copolymers obtained by reaction of N-vinylpyrrolidone with at least one monomer chosen from N-vinylformamide, vinyl acetate, ethylene, propylene, acrylamide and vinylcaprolactam. According to a preferred embodiment, the hydrophilic film- forming polymer(s) are chosen from vinylpyrrolidone homopolymers (PVP), vinylpyrrolidone/vinyl acetate copolymers, vinylpyrrolidone/styrene copolymers, vinylpyrrolidone/ethylene copolymers, vinylpyrrolidone/propylene copolymers, vinylpyrrolidone/vinylcaprolactam copolymers, vinylpyrrolidone/vinylformamide copolymers, vinylpyrrolidone/vinyl alcohol copolymers, and mixtures thereof.

Preferably, the film-forming polymer(s) are chosen from vinylpyrrolidone homopolymers (PVP), vinylpyrrolidone/vinyl acetate copolymers, vinylpyrrolidone/styrene copolymers, vinylpyrrolidone/ethylene copolymers, vinylpyrrolidone/propylene copolymers, vinylpyrrolidone/vinyl caprolactam copolymers, vinylpyrrolidone/vinylformamide copolymers, vinylpyrrolidone/vinyl alcohol copolymers, acrylamide copolymers, acrylic acid ester homopolymers or copolymers, ethylene homopolymers or copolymers, and mixtures thereof.

More preferentially, the film-forming polymer(s) are chosen from vinylpyrrolidone homopolymers (PVP), acrylamide copolymers, acrylic acid ester homopolymers or copolymers, ethylene homopolymers or copolymers, and mixtures thereof.

The film-forming polymer(s) may be present in a total amount ranging from 0.1 to 30% by weight, preferably from 0.5 to 25% by weight and better still from 1 to 20% by weight, relative to the total weight of composition B.

Composition A and/or B

Non-associative non-ionic cellulose-based polymer

Composition A and/or composition B according to the invention may comprise at least one nonionic, preferably non-associative, cellulose-based polymer.

The non-associative non-ionic cellulose-based polymer is different from the film-forming polymers mentioned previously.

According to the invention, the term “cellulose-based polymer” means any polysaccharide polymer having, in its structure, sequences of glucose residues joined together via beta- 1,4 bonds.

According to the invention, the term “non-associative cellulose-based polymer” means that the cellulose-based polymers do not include any Cx-Cao fatty chains.

The non-associative non-ionic cellulose-based polymers may be chosen from (Ci- C4)alkylcelluloses, such as methylcelluloses and ethylcelluloses (for example Ethocel Standard 100 Premium from Dow Chemical); hydroxy(Ci-C4)alkylcelluloses, such as hydroxymethylcelluloses, hydroxyethylcelluloses and hydroxypropylcelluloses; mixed hydroxy(Ci-C4)alkyl(Ci-C4)alkylcelluloses, such as hydroxypropylmethylcelluloses (for example Methocel E4M from Dow Chemical), hydroxyethylmethylcelluloses, hydroxyethylethylcelluloses (for example Bermocoll E 481 FQ from AkzoNobel), and hydroxybutylmethylcelluloses, and also mixtures thereof.

Preferably, the non-associative non-ionic cellulose-based polymer(s) are chosen from hydroxy (C i -C4)alkylcelluloses .

More preferentially, the non-associative non-ionic cellulose-based polymer(s) are hydroxyethylcellulose and/or hydroxypropylcellulose.

More preferentially, composition A and/or composition B comprise(s) hydroxy ethylcellulose and/or hydroxypropylcellulose.

In particular, mention may be made of the hydroxy ethylcellulose sold by the company Ashland Inc. under the trade name Natrosol 250 HRR PC and the hydroxypropylcellulose sold by the company Ashland Inc. under the trade name Klucel MF Pharm Hydroxypropylcellulose.

The non-ionic cellulose-based polymer(s) may be present in a total amount preferably ranging from 0.01 to 10% by weight, preferentially from 0.05 to 5% by weight and better still from 0.1 to 3% by weight relative to the total weight of composition A and/or composition B.

The non-associative non-ionic cellulose-based polymer(s) may be present in a total amount preferably ranging from 0.01 to 10% by weight, preferentially from 0.05 to 5% by weight and better still from 0.1 to 3% by weight relative to the total weight of composition A and/or composition B.

Pigment:

Composition A and/or composition B according to the invention comprise(s) at least one pigment. In the context of the present invention, the pigment(s) is/are coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously.

Preferably, composition A according to the invention comprises at least one pigment, said pigment being coated with at least one alkoxy silane of formula (I), (I’) or (II) as described previously.

The term "pigment” is understood to mean any pigment that gives colour to keratin materials. Their solubility in water at 25°C and at atmospheric pressure (760 mmHg) is less than 0.05% by weight, and preferably less than 0.01% by weight. The pigments that may be used are notably chosen from the organic and/or mineral pigments known in the art, notably those described in Kirk-Othmer’s Encyclopedia of Chemical Technology and in Ullmann’s Encyclopedia of Industrial Chemistry.

The pigments may be natural, of natural origin, or non-natural.

These pigments may be in pigment powder or paste form.

The pigments may be chosen, for example, from mineral pigments, organic pigments, lakes, special effect pigments such as nacres or glitter flakes, and mixtures thereof.

The pigment may be a mineral pigment. The term “mineral pigment” refers to any pigment that satisfies the definition in Ullmann’s encyclopedia in the chapter on inorganic pigments. Among the mineral pigments that are useful in the present invention, mention may be made of metal oxides and also hydrates of metal oxides, for instance aluminium oxides, boron oxides, germanium oxides, manganese oxides, notably manganese violet, magnesium oxides, iron oxides, cobalt oxides, chromium oxides, titanium oxides, notably titane oxide, vanadium oxides, zirconium oxides, tin oxides, zinc oxides, silicon oxides, aluminium hydrates, silicon hydrates, chromium hydrate, ultramarine blue, ferric blue, and mixtures thereof.

These mineral pigments may be selected as a function of their refractive index. Mineral pigments with a low refractive index have a refractive index less than or equal to 1.8, more preferentially less than 1.6.

Mineral pigments with a low refractive index include in particular aluminium oxides, aluminium hydrates, boron oxides, germanium oxides, manganese oxides, magnesium oxides, silicon oxides, silicon hydrates and mixtures thereof.

Mineral pigments with a high refractive index have a refractive index of greater than 1.9, more preferentially greater than 2.0, better still greater than 2.4. Mineral pigments with a high refractive index include in particular metal oxides that selectively absorb light, i.e. coloured metal oxides, such as for example iron (III) oxides of red colour, notably haematite (a-Fe2O3) and maghemite (y-Fc2O3), cobalt (II) oxides of blue colour, chromium (III) oxides of green colour, titanium (III) oxides of blue colour, notably as a mixture with titanium nitrides and oxynitrides, vanadium (V) oxides of orange colour, and mixtures thereof. Mineral pigments with a high refractive index also include non-coloured metal oxides, such as titanium dioxide and/or zirconium oxide.

The pigment may be an organic pigment. The term “organic pigment” refers to any pigment that satisfies the definition in Ullmann’s encyclopedia in the chapter on organic pigments.

The organic pigment may notably be chosen from nitroso, nitro, azo, xanthene, pyrene, quinoline, anthraquinone, triphenylmethane, fluorane, phthalocyanine, metal-complex, isoindolinone, isoindoline, quinacridone, perinone, perylene, diketopyrrolopyrrole, indigo, thioindigo, dioxazine, triphenylmethane and quinophthalone compounds.

In particular, the white or coloured organic pigments may be chosen from carmine, carbon black, aniline black, azo yellow, quinacridone, phthalocyanine blue, the blue pigments codified in the Color Index under the references CI 42090, 69800, 69825, 74100, 74160, the yellow pigments codified in the Color Index under the references CI 11680, 11710, 19140, 20040, 21100, 21108, 47000, 47005, the green pigments codified in the Color Index under the references CI 61565, 61570, 74260, the orange pigments codified in the Color Index under the references CI 11725, 45370, 71105, the red pigments codified in the Color Index under the references CI 12085, 12120, 12370, 12420, 12490, 14700, 15525, 15580, 15620, 15630, 15800, 15850, 15865, 15880, 26100, 45380, 45410, 58000, 73360, 73915, 75470, the pigments obtained by oxidative polymerization of indole or phenol derivatives as described in patent FR 2 679 771.

Examples that may also be mentioned include pigment pastes of organic pigments, such as the products sold by the company Hoechst under the names:

- Cosmenyl Yellow 10G: Yellow 3 pigment (CI 11710);

- Cosmenyl Yellow G: Yellow 1 pigment (CI 11680);

- Cosmenyl Orange GR: Orange 43 pigment (CI 71105);

- Cosmenyl Red R: Red 4 pigment (CI 12085);

- Cosmenyl Carmine FB: Red 5 pigment (CI 12490);

- Cosmenyl Violet RL: Violet 23 pigment (CI 51319);

- Cosmenyl Blue A2R: Blue 15.1 pigment (CI 74160);

- Cosmenyl Green GG: Green 7 pigment (CI 74260);

- Cosmenyl Black R: Black 7 pigment (CI 77266).

The pigments in accordance with the invention may also be in the form of composite pigments, as described in patent EP 1 184 426. These composite pigments may notably be composed of particles comprising an inorganic core, at least one binder for attaching the organic pigments to the core, and at least one organic pigment which at least partially covers the core.

The organic pigment may also be a lake. The term “lake” refers to dyes adsorbed onto insoluble particles, the assembly thus obtained remaining insoluble during use.

The inorganic substrates onto which the dyes are adsorbed are, for example, alumina, silica, calcium sodium borosilicate or calcium aluminium borosilicate and aluminium.

Among the dyes, mention may be made of carminic acid. Mention may also be made of the dyes known under the following names: D&C Red 21 (CI 45 380), D&C Orange 5 (CI 45 370), D&C Red 27 (CI 45 410), D&C Orange 10 (CI 45 425), D&C Red 3 (CI 45 430), D&C Red 4 (CI 15 510), D&C Red 33 (CI 17 200), D&C Yellow 5 (CI 19 140), D&C Yellow 6 (CI 15 985), D&C Green 5 (CI 61 570), D&C Yellow 10 (CI 77 002), D&C Green 3 (CI 42053), D&C Blue 1 (CI 42090).

An example of a lake that may be mentioned is the product known under the following name: D&C Red 7 (CI 15 850:1).

The pigment may also be a special effect pigment. The term “special effect pigments” means pigments that generally create a coloured appearance (characterized by a certain shade, a certain vivacity and a certain level of luminance) that is non-uniform and that changes as a function of the conditions of observation (light, temperature, angles of observation, etc.). They thereby differ from coloured pigments, which afford a standard uniform opaque, semi-transparent or transparent shade.

Several types of special effect pigments exist: those with a low refractive index, such as fluorescent or photochromic pigments, and those with a higher refractive index, such as nacres, interference pigments or glitter flakes.

Examples of special effect pigments that may be mentioned include nacreous pigments such as mica covered with titanium or with bismuth oxychloride, coloured nacreous pigments such as mica covered with titanium and with iron oxides, mica covered with iron oxide, mica covered with titanium and notably with ferric blue or with chromium oxide, mica covered with titanium and with an organic pigment as defined previously, and also nacreous pigments based on bismuth oxychloride. Nacreous pigments that may be mentioned include the nacres Cellini sold by BASF (mica-TiO2-lake), Prestige sold by Eckart (mica-TiO2), Prestige Bronze sold by Eckart (mica-Fe2O3), and Colorona sold by Merck (mica-TiO2-Fe2O3).

Mention may also be made of the gold-coloured nacres sold notably by the company BASF under the name Brilliant Gold 212G (Timica), Gold 222C (Cloisonne), Sparkle Gold (Timica), Gold 4504 (Chromalite) and Monarch Gold 233X (Cloisonne); the bronze nacres sold notably by the company Merck under the name Bronze Fine (17384) (Colorona) and Bronze (17353) (Colorona) and by the company BASF under the name Super Bronze (Cloisonne); the orange nacres sold notably by the company BASF under the name Orange 363C (Cloisonne) and Orange MCR 101 (Cosmica) and by the company Merck under the name Passion Orange (Colorona) and Matte Orange (17449) (Microna); the brown nacres sold notably by the company BASF under the name Nu-Antique Copper 340XB (Cloisonne) and Brown CE4509 (Chromalite); the nacres with a copper tint sold notably by the company BASF under the name Copper 340A (Timica); the nacres with a red tint sold notably by the company Merck under the name Sienna Fine (17386) (Colorona); the nacres with a yellow tint sold notably by the company BASF under the name Yellow (4502) (Chromalite); the red nacres with a gold tint sold notably by the company BASF under the name Sunstone G012 (Gemtone); the pink nacres sold notably by the company BASF under the name Tan Opal G005 (Gemtone); the black nacres with a gold tint sold notably by the company BASF under the name Nu- Antique Bronze 240 AB (Timica), the blue nacres sold notably by the company Merck under the name Matte Blue (17433) (Microna), the white nacres with a silvery tint sold notably by the company Merck under the name Xirona Silver, and the golden-green pink-orange nacres sold notably by the company Merck under the name Indian Summer (Xirona), and mixtures thereof.

Still as examples of nacres, mention may also be made of particles including a borosilicate substrate coated with titanium oxide.

Particles comprising a glass substrate coated with titanium oxide are notably sold under the name Metashine MC1080RY by the company Toyal.

Mention may also be made of the special effect pigments composed of Cu-Zn metal alloys sold under the name Rotoflex® by the company Eckart.

Finally, examples of nacres that may also be mentioned include polyethylene terephthalate glitter flakes, notably those sold by the company Meadowbrook Inventions under the name Silver IP 0.004X0.004 (silver glitter flakes). It is also possible to envisage multilayer pigments based on synthetic substrates, such as alumina, silica, calcium sodium borosilicate, calcium aluminium borosilicate and aluminium.

The special effect pigments may also be chosen from reflective particles, i.e. notably from particles of which the size, structure, notably the thickness of the layer(s) of which they are made and their physical and chemical nature, and surface state, allow them to reflect incident light. This reflection may, where appropriate, have an intensity sufficient to create at the surface of the composition or of the mixture, when it is applied to the support to be made up, highlight points that are visible to the naked eye, i.e. brighter points that contrast with their surroundings, making them appear to sparkle.

The reflective particles may be selected so as not to significantly alter the colouring effect generated by the colouring agents with which they are combined, and more particularly so as to optimize this effect in terms of colour rendition. They may more particularly have a yellow, pink, red, bronze, orange, brown, gold and/or coppery colour or tint.

These particles may have varied forms and may notably be in platelet or globular form, in particular in spherical form. The reflective particles, whatever their form, may or may not have a multilayer structure and, in the case of a multilayer structure, may have, for example, at least one layer of uniform thickness, notably of a reflective material.

When the reflective particles do not have a multilayer structure, they may be composed, for example, of metals such as copper, tin, zinc, and/or alloys thereof, or, for example, of metal oxides, preferably magnesium oxides, tin oxides, zinc oxides, cobalt oxides, nickel oxides, iron oxides, zirconium oxides, titanium oxides and cerium oxides, notably titanium or iron oxides obtained synthetically.

Reflective particles are notably described in JP-A-09188830, JP- A- 10158450, JP-A-10158541, JP-A-07258460 and JP-A-05017710.

The sizes of these reflective particles are preferably on average less than 50 nm, more preferentially less than 30 nm, better still less than 10 nm. The spacing between the particles is preferably less than 10 nm.

Mention may also be made of interference pigments which are not attached to a substrate, such as liquid crystals (Helicones HC from Wacker) or interference holographic glitter flakes (Geometric Pigments or Spectra f/x from Spectratek). Special effect pigments also comprise fluorescent pigments, whether these are substances that are fluorescent in daylight or that produce an ultraviolet fluorescence, phosphorescent pigments, photochromic pigments, thermochromic pigments and quantum dots, sold, for example, by the company Quantum Dots Corporation.

The variety of pigments that may be used in the present invention makes it possible to obtain a wide range of colours, and also particular optical effects such as metallic effects or interference effects.

The size of the pigment used in the composition according to the present invention is generally between 5 nm and 200 pm, preferably between 7 nm and 80 pm and more preferentially between 10 nm and 50 pm.

Preferably, the pigment(s) is (are) chosen from mineral, mixed mineral-organic or organic pigments.

More preferentially, the pigment(s) is (are) chosen from mineral pigments.

According to a preferred embodiment, the pigment(s) according to the invention is (are) chosen from mineral pigments, preferably iron oxides, notably iron (III) oxides such as Fe2<D3.

The pigment(s) as described previously is (are) coated with at least one alkoxy silane of formula (I), (I’), or (II) as described previously, oligomers thereof and/or mixtures thereof. Preferably, the pigment(s) according to the invention is (are) coated with at least one alkoxysilane of formula (I), or of formula (II) as described previously, oligomers thereof and/or mixtures thereof.

Preferably, the pigment(s) according to the invention is (are) coated with at least one alkoxysilane of formula (II) as described previously, oligomers thereof and/or mixtures thereof. Among the alkoxy silanes of formula (II) suitable for coating the pigment, mention may notably be made of tetramethoxysilane (TMOS), tetraethoxy silane (TEOS), tetraisopropoxysilane, methyltrimethoxy silane (MTMS), methyltriethoxy silane (MTES), ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane (or triethoxycaprylylsilane), dodecyltrimethoxysilane, dodecyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, dimethyldiethoxysilane (DMDES), diethyldiethoxysilane, dipropyldiethoxysilane, phenyltriethoxysilane, phenylmethyldiethoxysilane, diphenyldiethoxysilane, benzyltriethoxysilane, benzylmethyldiethoxysilane, dibenzyldiethoxysilane, acetoxymethyltriethoxysilane and mixtures thereof.

The alkoxysilane(s) of formula (II) used for coating the pigment, oligomers thereof and/or mixtures thereof may be identical to or different from the alkoxy silanes of formula (II) present in composition A.

Preferably, the alkoxysilane(s) of formula (II) used for coating the pigment, oligomers thereof and/or mixtures thereof is (are) different from the alkoxysilanes of formula (II) present in composition A.

More preferentially, the pigments(s) according to the invention is (are) coated with at least one alkoxysilane of formula (lib) below, oligomers thereof and/or mixtures thereof:

in which:

- Ra represents an alkyl group containing from 1 to 20 carbon atoms, preferably from 1 to 10 carbon atoms, more preferentially from 2 to 8 carbon atoms, said alkyl group being optionally substituted with an aryl group; an alkoxy group containing from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms such as an ethoxy;

- Rb represents an alkyl group containing from 1 to 20 carbon atoms, preferably from 1 to 6 carbon atoms and notably from 1 to 4 carbon atoms, notably an ethyl;

- Rc represents an alkoxy group containing from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms, such as an ethoxy;

- k denotes an integer ranging from 0 to 3;

- Rf represents an alkyl group containing from 1 to 10 carbon atoms and notably from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms, such as an ethyl.

Preferably, the pigments(s) according to the invention is (are) coated with at least one alkoxysilane of formula (lib), oligomers thereof and/or mixtures thereof, such that:

- Ra represents an alkyl group containing from 1 to 10 carbon atoms, more preferentially from 2 to 8 carbon atoms, such as an octyl;

- Rb represents an alkyl group containing from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms, notably an ethyl;

- Rc represents an alkoxy group containing from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms, such as an ethoxy;

- k is equal to 0;

- Rf represents an alkyl group containing from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms, such as an ethyl.

According to a preferred embodiment, the alkoxy silane of formula (lib) used for coating the pigment, oligomers thereof, and/or mixtures thereof is triethoxycaprylylsilane.

According to a preferred embodiment, the pigment(s) according to the invention is (are) chosen from iron oxides, notably iron (III) oxides such as Fe2O3, the alkoxysilane of formula (lib) used for coating said pigment is triethoxycaprylylsilane.

Iron (III) oxide Fe2O3 coated with triethoxycaprylylsilane is sold by the company KOBO under the trade name BWRO-11S2.

The alkoxysilane(s) used for coating the pigments may be present in a total content ranging from 0.01 to 15%, preferably from 0.1 to 10%, preferentially from 0.5 to 5% by weight relative to the total weight of the coated pigment.

The alkoxysilane(s) used for coating the pigment may be present in a total content ranging from 0.001 to 10%, preferably from 0.01 to 5%, preferentially from 0.1 to 1% by weight relative to the total weight of composition A and/or of composition B. The pigments may be dispersed in the composition by means of a dispersant.

The dispersant serves to protect the dispersed particles against agglomeration or flocculation thereof. This dispersant may be a surfactant, an oligomer, a polymer or a mixture of several thereof, bearing one or more functionalities with strong affinity for the surface of the particles to be dispersed. In particular, they may become physically or chemically attached to the surface of the pigments. These dispersants also contain at least one functional group that is compatible with or soluble in the continuous medium. In particular, esters of 12-hydroxy stearic acid in particular and of C8 to C20 fatty acid and of polyols such as glycerol or diglycerol are used, such as poly( 12-hydroxy stearic acid) stearate with a molecular weight of approximately 750 g/mol, such as the product sold under the name Solsperse 21 000 by the company Avecia, polyglyceryl-2 dipolyhydroxystearate (CTFA name) sold under the reference Dehymyls PGPH by the company Henkel, or else polyhydroxystearic acid such as the product sold under the reference Arlacel Pl 00 by the company Uniqema, and mixtures thereof.

As other dispersants that may be used in the compositions of the invention, mention may be made of quaternary ammonium derivatives of polycondensed fatty acids, for instance Solsperse 17 000 sold by the company Avecia, and polydimethylsiloxane/oxypropylene mixtures such as those sold by the company Dow Coming under the references DC2-5185 and DC2-5225 C. According to a particular embodiment of the invention, the dispersant is present with organic or inorganic pigments in submicron- sized particulate form in the dye composition.

The term “submicron-sized” or “submicronic” refers to pigments having a particle size that has been micronized by a micronization method and having a mean particle size of less than a micrometre (pm), in particular between 0.1 and 0.9 pm, and preferably between 0.2 and 0.6 pm.

According to one embodiment, the dispersant and the pigment(s) are present in a (dispersant:pigment) amount of between 1: 4 and 4: 1, particularly between 1.5: 3.5 and 3.5: 1 or better still between 1.75: 3 and 3: 1.

The dispersant(s) may thus have a silicone backbone, such as silicone polyether and dispersants of aminosilicone type, different from the alkoxy silanes of formula (I) or formula (I’) described previously in the application. Among the suitable dispersants that may be mentioned are: aminosilicones, i.e. silicones comprising one or more amino groups such as those sold under the names and references: BYK LPX 21879 by BYK, GP-4, GP-6, GP-344, GP-851, GP- 965, GP-967 and GP-988-1, sold by Genesee Polymers, silicone acrylates such as Tego® RC 902, Tego® RC 922, Tego® RC 1041, and Tego® RC 1043, sold by Evonik, poly dimethylsiloxane (PDMS) silicones bearing carboxyl groups such as X-22162 and X-22370 by Shin-Etsu, epoxy silicones such as GP-29, GP-32, GP-502, GP-504, GP-514, GP- 607, GP-682, and GP-695 by Genesee Polymers, or Tego® RC 1401, Tego® RC 1403, Tego® RC 1412 by Evonik.

According to one particular embodiment, the dispersant(s) are of aminosilicone type, different from the alkoxy silanes of formula (I) or formula (I’) described previously in the application and are cationic.

The pigment(s) coated with at least one alkoxysilane of formula (I), (I’) or (II) may be present in a total amount ranging from 0.05 to 20% by weight, preferably from 0.1 to 15% by weight and better still from 0.5 to 10% by weight, relative to the total weight of composition A and/or composition B.

According to one particular embodiment, composition A and/or composition B may comprise a pigment other than the pigments coated with at least one alkoxy silane of formula (I), (I’) or (II) as described previously.

Solvents:

Composition A and/or composition B used in the context of the process according to the invention may comprise water.

Preferably, water is present in a content ranging from 0.1% to 99% by weight, more preferentially from 1% to 98% by weight and better still from 10% to 97% by weight relative to the total weight of composition A and/or composition B.

When composition A and/or composition B according to the invention comprise(s) water, the pH of composition A and/or composition B is preferably alkaline, more preferentially the pH of composition A and/or composition B is between 9 and 11.

For the purpose of adjusting the pH, composition A and/or composition B may comprise an alkaline agent.

Preferably, composition A and/or composition B according to the invention comprises an alkaline agent.

The pH of the compositions is measured at room temperature.

As alkaline agent, mention may be made of aqueous ammonia, alkanolamines and/or basic amino acids.

Preferably, the alkanolamine(s) are chosen from monoethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, N-dimethylaminoethanolamine, 2-amino-2- methyl-1 -propanol, triisopropanolamine, 2-amino-2-methyl-l,3-propanediol, 3-amino-l,2- propanediol, 3-dimethylamino-l,2-propanediol and tris(hydroxymethylamino)methane.

More preferentially, the alkanolamine(s) are chosen from monoethanolamine and/or 2-amino- 2-methyl-l -propanol.

For the purposes of the present invention, the term “ amino acid'” means organic compounds containing two functional groups: both a carboxyl -COOH or carboxylate group and an amine group -NH2, it being possible for the amine group to be optionally methylated, i.e. in the form -NR2 or N⁺R₃, where at least one R = CH3.

Preferably, the amino acid(s) are chosen from aminocarboxylic acids such as alphaaminocarboxylic acid.

The term “basic amino acid” is intended to mean amino acids having an isoelectric point above 7.

Preferably, the basic amino acid(s) are chosen from arginine, lysine, ornithine and/or histidine, more preferentially arginine and/or lysine.

According to one particular embodiment, composition A and/or composition B may comprise an inorganic alkaline agent, preferably chosen from ammonium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, sodium phosphate, potassium phosphate, sodium silicate, sodium metasilicate, potassium silicate, sodium carbonate and/or potassium carbonate.

Composition A and/or composition B may also comprise acidifying agents to adjust the pH. Preferably, the acidifying agents are chosen from citric acid, lactic acid, acetic acid and/or mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid and mixtures thereof.

Additives:

Composition A and/or composition B according to the invention may also contain any commonly used adjuvant or additive.

Among the additives that may be contained in the composition, mention may be made of reducing agents, thickeners other than the polymers described previously, softeners, antifoams, moisturizers, UV-screening agents, peptizers, dispersants, fragrances, anionic, cationic, nonionic or amphoteric surfactants, proteins, vitamins, preserving agents, fillers, waxes and mixtures thereof.

Composition A and/or composition B may notably be in the form of a suspension, a dispersion, a gel, an emulsion, notably an oil-in-water (O/W) or water-in-oil (W/O) emulsion, or a multiple emulsion (W/O/W or polyol/O/W or O/W/O), in the form of a cream, a foam, a stick, a dispersion of vesicles, notably of ionic or non-ionic lipids, or a two-phase or multi-phase lotion, an anhydrous liquid or an anhydrous gel.

According to a particular embodiment, composition A according to the invention is an anhydrous liquid or an anhydrous gel.

According to a particular embodiment, composition B according to the invention is a dispersion. A person skilled in the art may select the appropriate presentation form, and also the method for preparing it, on the basis of his/her general knowledge, taking into account firstly the nature of the constituents used, notably their solubility in the support, and secondly the intended application of composition A and/or composition B.

According to one preferred embodiment, composition A according to the invention comprises at least one alkoxysilane of formula (I) as described previously, at least one alkoxysilane of formula (II) as described previously, and at least one pigment coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously.

According to a more preferred embodiment, composition A according to the invention comprises 3 -aminopropyltriethoxy silane (APTES), methyltrimethoxy silane (MTMS) or methyltriethoxysilane (MTES) and at least one pigment coated with at least one alkoxysilane of formula (lib) as described previously.

According to a more preferred embodiment, composition A according to the invention comprises 3 -aminopropyltriethoxy silane (APTES), methyltrimethoxy silane (MTMS) or methyltriethoxysilane (MTES) and at least one iron oxide, preferably an iron (III) oxide such as Fe2O3 as pigment, said pigment being coated with at least one alkoxysilane of formula (lib) as described previously, preferably triethoxycaprylylsilane.

According to one preferred embodiment, composition B according to the invention comprises at least one film-forming polymer chosen from vinylpyrrolidone homopolymers (PVP), vinylpyrrolidone copolymers, acrylamide copolymers, acrylic acid ester homopolymers or copolymers, ethylene homopolymers or copolymers and mixtures thereof.

According to a more preferred embodiment, composition B according to the invention comprises at least one film-forming polymer chosen from vinylpyrrolidone homopolymers (PVP), acrylamide copolymers, acrylic acid ester homopolymers or copolymers, ethylene homopolymers or copolymers and mixtures thereof.

Process for treating keratin fibres

A subject of the present invention is a process for dyeing keratin fibres such as the hair, comprising the following steps: 1 a) applying to the keratin fibres at least one composition A comprising:

- at least one alkoxy silane chosen from the compounds of formula (I) or of formula (I’) as described previously, oligomers thereof and/or mixtures thereof, and

- at least one alkoxysilane of formula (II) as described previously, oligomers thereof and/or mixtures thereof, and b) applying to the keratin fibres at least one composition B comprising at least one film-forming polymer as described previously, composition A and/or composition B comprising at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously.

Preferably, composition A and composition B according to the invention are compositions for dyeing keratin fibres such as the hair.

Composition A and composition B can be applied simultaneously or sequentially. Preferably, composition A and composition B are applied sequentially.

Thus, preferably, composition A is first of all applied to the keratin fibres, followed by composition B in a second step.

According to a preferred embodiment, the process for dyeing keratin fibres such as the hair comprises: i) applying to said keratin fibres composition A according to the invention comprising:

- at least one alkoxy silane chosen from the compounds of formula (I) or of formula (I’) as described previously, oligomers thereof and/or mixtures thereof,

- at least one alkoxysilane of formula (II) as described previously, oligomers thereof and/or mixtures thereof, and

- at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously, ii) optionally a leave-on time of from 10 seconds to 20 minutes, notably from 20 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, of composition A on said fibres, iii) optionally a step of washing, rinsing, wringing out or drying said fibres, iv) applying to said keratin fibres composition B according to the invention comprising at least one film-forming polymer as described previously, v) optionally a leave-on time of from 10 seconds to 20 minutes, notably from 20 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, of composition B according to the invention on said fibres, vi) optionally a step of washing, rinsing, wringing out and vii) optionally a step of drying and/or heating the keratin fibres for example at a temperature of greater than or equal to 30°C.

- at least one alkoxysilane of formula (II) as described previously, oligomers thereof and/or mixtures thereof, ii) optionally a leave-on time of from 10 seconds to 20 minutes, notably from 20 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, of composition A on said fibres, iii) optionally a step of washing, rinsing, wringing out or drying said fibres, iv) applying composition B according to the invention, comprising:

- at least one film-forming polymer as described previously, and

- at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously, v) optionally a leave-on time of from 10 seconds to 20 minutes, notably from 20 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, of composition B according to the invention on said fibres, vi) optionally a step of washing, rinsing, wringing out and vii) optionally a step of drying and/or heating the keratin fibres for example at a temperature of greater than or equal to 30°C.

- at least one alkoxysilane of formula (II) as described previously, oligomers thereof and/or mixtures thereof,

- at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously, ii) optionally a leave-on time of from 10 seconds to 20 minutes, notably from 20 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, of composition A on said fibres, iii) optionally a step of washing, rinsing, wringing out or drying said fibres, iv) applying composition B according to the invention comprising:

- at least one film-forming polymer as described previously, and

A “rinsing step” is understood to mean the application of water to the keratin fibres.

Compositions A and B according to the invention can be used on wet or dry keratin fibres, and also on all types of fair or dark, natural or dyed, permanent- waved, bleached or relaxed, fibres. According to one particular embodiment of the process of the invention, the fibres are washed before applying compositions A and B according to the invention.

The application of compositions A and B according to the invention to the keratin fibres can be carried out by any conventional means, in particular using a comb, a fine brush, a coarse brush or with the fingers.

The dyeing process, i.e. application of compositions A and B according to the invention to the keratin fibres, is generally carried out at room temperature (between 15°C and 25°C).

After application of composition A or composition B to the keratin fibres, it is preferable to have a leave-on time of from 10 seconds to 20 minutes, notably from 20 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, of composition A or composition B on said fibres.

According to a preferred embodiment, the process for dyeing keratin fibres such as the hair comprises: i) preparing composition A according to the invention by mixing a first composition A’ and a second composition A” in which the first composition A’ comprises:

- at least one alkoxysilane of formula (II) as described previously, oligomers thereof and/or mixtures thereof, and the second composition A” comprises at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously, ii) applying to said keratin fibres composition A according to the invention, iii) optionally a leave-on time of from 10 seconds to 20 minutes, notably from 20 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, of composition A on said fibres, iv) optionally a step of washing, rinsing, wringing out or drying said fibres, v) applying composition B according to the invention comprising at least one film-forming polymer as described previously, and vi) optionally a leave-on time of from 10 seconds to 20 minutes, notably from 20 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, of composition B according to the invention on said fibres, vii) optionally a step of washing, rinsing, wringing out and viii) optionally a step of drying and/or heating the keratin fibres for example at a temperature of greater than or equal to 30°C.

In order to allow better preservation of composition A’, the latter preferably comprises a low water content or is anhydrous.

Preferably, composition A’ comprises a water content of between 0.001 and 10% by weight, better still between 0.5 and 10% by weight, more preferentially between 1 and 8% by weight relative to the weight of composition A’.

Composition A’ ’ may also contain water.

According to a particular embodiment, the process for dyeing keratin fibres such as the hair comprises: i) preparing composition A according to the invention by mixing a first composition A’ and a second composition A”, in which the first composition A’ comprises:

- at least one alkoxysilane of formula (II) as described previously, oligomers thereof and/or mixtures thereof, and the second composition A” comprises at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously, and ii) applying to said keratin fibres composition A according to the invention, iii) optionally a leave-on time of from 10 seconds to 20 minutes, notably from 20 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, of composition A on said fibres, iv) optionally a step of washing, rinsing, wringing out or drying said fibres, v) applying composition B according to the invention comprising:

- at least one film-forming polymer as described previously, and - at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously, vi) optionally a leave-on time of from 10 seconds to 20 minutes, notably from 20 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, of composition B according to the invention on said fibres, vii) optionally a step of washing, rinsing, wringing out and viii) optionally a step of drying and/or heating the keratin fibres for example at a temperature of greater than or equal to 30°C.

After applying compositions A and B according to the invention and before a possible step of applying heat to the keratin fibres, the keratin fibres may be subjected to a drying step, for example using a hairdryer.

The drying step may be performed for a period of between 20 seconds and 5 minutes.

The drying step may be performed using absorbent paper, a hairdryer or a styling hood or by drying naturally.

Preferably, the drying step is performed using a hairdryer at a temperature greater than or equal to 30°C, more particularly at a temperature above 30°C and below 110°C.

After applying compositions A and B according to the invention to the keratin fibres, it is possible to wait at least 10 seconds, preferably at least 30 seconds, before the step of drying the keratin fibres.

After application of compositions A and B according to the invention and optionally a step of drying the keratin fibres, the process according to the invention may comprise a step of applying heat to the keratin fibres using a heating tool.

Preferably, the process according to the invention does not comprise a step of applying heat to the keratin fibres using a heating tool in addition to the possible drying step.

The heat application step of the process of the invention can be carried out using a hood, a hairdryer, a straightening iron, a curling iron, a Climazon etc.

Preferably, the heat application step of the process of the invention is performed using a hairdryer and/or a straightening iron, more preferentially using a hairdryer.

During the step of applying heat to the keratin fibres, a mechanical action may be exerted on the locks, such as combing, brushing or running the fingers through.

When the step of applying heat to the keratin fibres is performed using a hood or a hairdryer, the temperature is preferably between 30°C and 110°C, preferentially between 50°C and 90°C. When the step of applying heat to the keratin fibres is performed using a straightening iron, the temperature is preferably between 110°C and 240°C, preferably between 110°C and 200°C. Multicompartment device (kit)

- in a first compartment, a composition A comprising:

- in a second compartment, a composition B according to the invention comprising at least one film-forming polymer, composition A and/or composition B comprising at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously.

According to a preferred embodiment, the kit for dyeing keratin fibres such as the hair comprises several compartments containing:

- in a first compartment, a composition A according to the invention comprising:

- at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously,

- in a second compartment, a composition B according to the invention comprising at least one film-forming polymer as described previously.

- in a first compartment, a composition A’ comprising:

- at least one alkoxysilane of formula (II) as described previously, oligomers thereof and/or mixtures thereof;

- in a second compartment, a composition A” comprising at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as described previously,

- in a third compartment, a composition B according to the invention comprising at least one film-forming polymer as described previously. The present invention will now be described more specifically by means of examples, which do not in any way limit the scope of the invention. However, the examples make it possible to support specific features, variants and preferred embodiments of the invention.

Example

In the examples, the temperature is given in degrees Celsius and corresponds to room temperature (20-25°C), unless otherwise indicated, and the pressure is atmospheric pressure, unless otherwise indicated.

The following compositions were prepared (in g/100 g of starting material as obtained): [Table 1]

[Table 2]

[Table 3]

(1) Sold under the trade name KBE-903 by the company Shin-Etsu;

(2) Sold under the trade name Sunpuro Red Iron Oxide by the company Sun;

(3) Sold under the trade name BWRO-11S2 by the company Kobo; (4) Sold under the trade name Ecosmooth Satin by the company Dow Coming (containing 25% active material in water).

Protocol:

Composition A’ was mixed with comparative composition Al” on the one hand and composition A2’ ’ according to the invention on the other hand in a 50/50 ratio in order to obtain compositions Al and A2.

Comparative composition Al and composition A2 according to the invention were applied by finger to locks of dry chestnut-brown hair (TD4), in a proportion of 1 g of composition per gram of lock.

The locks of hair were left for 2 minutes at room temperature.

Composition B was then applied by finger to the locks of hair treated respectively with composition Al or composition A2, in a proportion of 1 g of composition per gram of lock. The locks of hair were left for 5 minutes at room temperature.

The locks of hair were then dried with a hairdryer for 2 minutes.

The locks of hair were left at room temperature for 24 hours.

The locks of hair thus dyed were subjected to a shampoo wash so as to evaluate the fastness (persistence) of the colouring obtained with respect to shampoo washing, according to the shampoo washing protocol described below.

Shampoo washing protocol:

The shampoo washing operation was carried out on the locks obtained after the application of the hairdryer.

The locks of hair were washed with a standard shampoo (Garnier Ultra Doux).

The locks of hair were then rinsed, combed and dried with a hairdryer.

Results:

The persistence of the colour of the locks with respect to shampoo washing was evaluated in the CIE L*a*b* system, using a Minolta Spectrophotometer CM3600A colorimeter (illuminant D65, angle 10°, specular component included).

In this L*a*b* system, L* represents the intensity of the colour, a* indicates the green/red colour axis and b* the blue/yellow colour axis. The persistence of the colouring is evaluated by the colour difference AE between the coloured locks before shampooing, then after having undergone one shampoo wash according to the protocol described above. The lower the AE value, the more persistent the colour with respect to shampoo washing.

The AE value is calculated according to the following equation:

[Math.l]

In this equation, L*, a* and b* represent the values measured after dyeing the hair and after having undergone a shampoo wash, and LO*, aO* and bO* represent the values measured after dyeing the hair and before shampoo washing.

The results are shown in the table below:

[Table 4]

The locks of hair dyed with compositions A2 + B according to the invention comprising at least one pigment coated with at least one alkoxysilane then washed with a shampoo have low values of AE with respect to the locks of hair dyed with comparative compositions Al + B not comprising a pigment coated with at least one alkoxysilane then washed with a shampoo.

The coloured coating obtained using the process according to the invention thus exhibits good persistence with respect to shampoo washing.

Claims

1. Process for dyeing human keratin fibres such as the hair, comprising the following steps: a) applying to the keratin fibres at least one composition A comprising:

- at least one alkoxy silane chosen from the compounds of formula (I) or formula (I’) below, oligomers thereof and/or mixtures thereof:

(D in which:

- Rd and R_e, which may be identical or different, represent a hydrogen atom; an alkyl group containing from 1 to 20 carbon atoms, preferably from 1 to 6 carbon atoms and notably from 1 to 4 carbon atoms; a cycloalkyl group containing from 3 to 20 carbon atoms; an aryl group containing from 6 to 12 carbon atoms; an aminoalkyl group containing from 1 to 20 carbon atoms; - A independently represents a linear or branched alkylene group containing from 1 to 10 carbon atoms, which may be interrupted with at least one hetero atom chosen from O, S, NH or a carbonyl group (CO), preferably NH;

- Q represents a carbonyl group (CO);

- r denotes an integer ranging from 0 to 1 ; and

- at least one alkoxysilane of formula (II) below, oligomers thereof and/or mixtures thereof:

(ID in which:

- Rc represents an alkyl group containing from 1 to 20 carbon atoms, preferably from 1 to 10 carbon atoms, more preferentially from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms such as a methyl, said alkyl group being optionally substituted with an aryl group; an alkoxy group containing from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms such as an ethoxy; or an aryl group containing from 6 to 12 carbon atoms; it being understood that, if R_a and Rc do not represent an alkoxy group, then Rb cannot represent a hydrogen atom;

- k denotes an integer ranging from 0 to 5, preferably ranging from 0 to 3;

in which R_n represents a hydroxyl group (OH); an alkyl group containing from 1 to 10 carbon atoms, preferably a methyl, and b) applying to the keratin fibres at least one composition B comprising at least one film-forming polymer, composition A and/or composition B comprising at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’) or (II) as defined above.

2. Process according to Claim 1, in which the alkoxy silane(s), oligomers thereof and/or mixtures thereof are chosen from the compounds of formula (I) in which:

- Rd and Re, which are identical, represent a hydrogen atom or Rd denotes a hydrogen atom and R_e denotes a Cs-Ce cycloalkyl radical such as cyclohexyl;

- A independently represents a linear or branched alkylene group containing from 1 to 10 carbon atoms, which may be interrupted with at least one heteroatom chosen from O, S and NH or a carbonyl group (CO), preferably NH;

- r denotes an integer equal to 0.

3. Process according to either one of the preceding claims, in which the alkoxysilane(s), oligomers thereof and/or mixtures thereof are chosen from the compounds of formula (I) in which R_a represents an ethoxy group, Rb and Rc are identical and represent an ethyl, Rd and R_e represent a hydrogen atom, A represents a propylene and r denotes an integer equal to 0.

4. Process according to any one of the preceding claims, in which the alkoxysilane(s) of formula (I) or of formula (I’), oligomers thereof and/or mixtures thereof is (are) present in a total amount ranging from 0.1 to 40% by weight, preferably from 0.5 to 30% by weight, preferentially from 0.75 to 25% by weight, better still from 1 to 20% by weight and even better still from 1.5 to 15% by weight, relative to the total weight of composition A.

5. Process according to any one of the preceding claims, in which the alkoxy silane(s) of formula (II), oligomers thereof and/or mixtures thereof, are such that:

- k denotes an integer equal to 0;

- Rf represents an alkyl group containing from 1 to 10 carbon atoms and notably from 1 to 4 carbon atoms, such as a methyl or an ethyl, preferably methyltrimethoxy silane (MTMS) or methyltriethoxy silane (MTES).

6. Process according to any one of the preceding claims, in which the alkoxysilane(s) of formula (II), oligomers thereof and/or mixtures thereof is (are) present in a total amount ranging from 0.5 to 90% by weight, preferably from 1 to 75% by weight, preferentially from 3 to 45% by weight and better still from 5 to 40% by weight relative to the total weight of composition A.

7. Process according to any one of the preceding claims, in which the film-forming polymer(s) are chosen from vinylpyrrolidone homopolymers (PVP), acrylamide copolymers, acrylic acid ester homopolymers or copolymers, ethylene homopolymers or copolymers and mixtures thereof.

8. Process according to any one of the preceding claims, in which the film-forming polymer(s) is (are) present in a total amount ranging from 0.1 to 30% by weight, preferably from 0.5 to 25% by weight and better still from 1 to 20% by weight, relative to the total weight of composition B.

9. Process according to any one of the preceding claims, in which the pigment(s) is (are) chosen from mineral pigments, preferably iron oxides, notably iron(III) oxides such as Fe2<D3.

10. Process according to any one of the preceding claims, in which the pigment(s) according to the invention is (are) coated with at least one alkoxysilane of formula (lib) below, oligomers thereof and/or mixtures thereof:

in which:

- k denotes an integer ranging from 0 to 3;

11. Process according to the preceding claim, in which the pigment(s) according to the invention is (are) coated with at least one alkoxysilane of formula (lib), oligomers thereof and/or mixtures thereof such that:

- Rc represents an alkoxy group containing from 1 to 4 carbon atoms and in particular from 1 to 2 carbon atoms, such as an ethoxy; - k is equal to 0;

12. Process according to any one of the preceding claims, in which the pigment(s) coated with at least one alkoxysilane of formula (I), (I’) or (II) is (are) present in a total amount ranging from 0.05 to 20% by weight, preferably from 0.1 to 15% by weight, better still from 0.5 to 10% by weight relative to the total weight of composition A and/or of composition B.

13. Process according to any one of the preceding claims, in which composition A and/or composition B comprise(s) at least one non-associative, non-ionic cellulose-based polymer chosen from hydroxy (C1-C4) alkyl celluloses, preferably hydroxy ethylcellulose and/or hy droxypropy Icellulo se .

14. Process according to the preceding claim, in which the non-associative non-ionic cellulose-based polymer(s) is (are) present in a total amount ranging preferably from 0.01 to 10% by weight, preferentially from 0.05 to 5% by weight and better still from 0.1 to 3% by weight relative to the total weight of composition A and/or composition B.

15. Kit for dyeing keratin fibres such as the hair, comprising several compartments containing:

- in a first compartment, a composition A comprising:

- at least one alkoxy silane chosen from the compounds of formula (I) or of formula (I’) as described according to any one of Claims 1 to 4, oligomers thereof and/or mixtures thereof; and

- at least one alkoxy silane of formula (II) as described according to any one of Claims 1, 5 or 6, oligomers thereof and/or mixtures thereof;

- in a second compartment, a composition B comprising at least one film-forming polymer as described according to any one of Claims 1, 7 or 8, composition A and/or composition B comprising at least one pigment, said pigment being coated with at least one alkoxysilane of formula (I), (I’), or of formula (II) as described according to any one of Claims 1 to 3, 5, 9-12.