WO2017108595A1

WO2017108595A1 - Process for treating keratin fibres with a maleic anhydride block polymer and a polyol

Info

Publication number: WO2017108595A1
Application number: PCT/EP2016/081345
Authority: WO
Inventors: Bertrand Lion; Julien PORTAL
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2015-12-22
Filing date: 2016-12-16
Publication date: 2017-06-29
Anticipated expiration: 2018-06-22
Also published as: FR3045372B1; FR3045372A1

Abstract

The invention relates to a cosmetic process for treating keratin fibres, comprising the application to the keratin fibres of a mixture of a maleic anhydride block polymer, a liposoluble polyol and an amine catalyst; said block polymer comprising: a first block with a glass transition temperature (Tg) of greater than or equal to 40°C, obtained from a monomer CH₂ = C(R₁)-COOR₂ in which R₁ = H or methyl, R₂ = C₄ to C₁₂ cycloalkyl group; and a second block with a glass transition temperature (Tg) of less than or equal to 20°C derived from a maleic anhydride monomer and from a monomer CH₂ = C(R₁)-COOR₃ in which R1 = H or methyl, R₃ = linear or branched C₁ to C₆ unsubstituted alkyl group, with the exception of a tert-butyl group or a methoxyethyl group; and a step of heating the keratin fibres to a temperature ranging from 90°C to 250°C. The invention also relates to the crosslinked polymer obtained by reacting said block polymer with said liposoluble polyol. The treated keratin fibres have good water-resistant fixing properties.

Description

Process for treating keratin fibres with a maleic anhydride block polymer and a polyol

The present invention relates to a cosmetic process for treating keratin fibres using a block polymer bearing maleic anhydride groups and a liposoluble polyol, and also to a kit for performing said process.

Hair products generally contain film-forming polymers to give the hair good hairstyle hold. However, the quality of the hair hold may be impaired on contact with water, for example with rain or when showering: this impairment may be due to the fact that the deposit of the film-forming polymer on the hair has poor resistance to contact with water and is removed over time.

The aim of the present invention is to provide a polymer for obtaining a film-forming deposit that has good water resistance and that is suitable for application to the hair to obtain good fixing properties.

The inventors have discovered that a particular maleic anhydride block polymer combined with a particular polyol, applied to the hair, affords good hair-fixing properties, with good water resistance.

More precisely, a subject of the present invention is a process, especially a cosmetic process, for treating keratin fibres, comprising:

(i) a step of applying to the keratin fibres an (extemporaneous) mixture of a maleic anhydride block polymer, or of a cosmetic composition comprising it, of a liposoluble polyol compound or of a cosmetic composition containing it, and of an amine catalyst; said block polymer comprising:

at least one first block with a glass transition temperature (Tg) of greater than or equal to 40°C and obtained from at least one (meth)acrylate monomer of formula CH₂ = C(Ri)-COOR₂ in which R-i represents H or a methyl radical, R₂ represents a C₄ to Ci₂ cycloalkyl group; and

at least one second block with a glass transition temperature (Tg) of less than or equal to 20°C and obtained from at least one maleic anhydride monomer and from at least one (meth)acrylate monomer of formula CH₂ = C(Ri)-COOR₃ in which R-i represents H or a methyl radical, R₃ representing a linear or branched Ci to C₆ unsubstituted alkyl group, with the exception of a tert-butyl group or a methoxyethyl group;

(ii) a step of heating the keratin fibres to a temperature ranging from 90°C to 250°C;

steps (i) and (ii) being performed at the same time or separately, in the order (i) and then (ii). A subject of the invention is also a composition, especially a cosmetic composition, obtained by mixing said maleic anhydride block polymer or a composition containing it and comprising a physiologically acceptable medium, a liposoluble polyol compound or a composition containing it and comprising a physiologically acceptable medium, and an amine catalyst, as defined below.

A subject of the invention is also a kit comprising:

a first composition comprising said maleic anhydride block polymer as described previously and optionally comprising a physiologically acceptable medium, and

a second composition comprising a liposoluble polyol compound as described previously and optionally comprising a physiologically acceptable medium,

the first composition or the second composition also comprising said amine catalyst, the first and second compositions each being packaged in a separate packaging assembly.

The composition packaging assembly is, in a known manner, any packaging that is suitable for storing cosmetic compositions (especially a bottle, tube, spray bottle or aerosol bottle).

Such a kit makes it possible to carry out the process for treating keratin materials according to the invention.

The block polymer used according to the invention comprises:

at least one second block with a glass transition temperature (Tg) of less than or equal to 20°C and obtained from at least one maleic anhydride monomer and from at least one (meth)acrylate monomer of formula CH₂ = C(Ri)-COOR₃ in which R-i represents H or a methyl radical, R₃ representing a linear or branched Ci to C₆ unsubstituted alkyl group, with the exception of a tert-butyl group or a methoxyethyl group.

The glass transition temperatures indicated for the first and second blocks may be theoretical Tg values determined from the theoretical Tg values of the constituent monomers of each of the blocks, which may be found in a reference manual such as the Polymer Handbook, 3rd Edition, 1989, John Wiley, according to the following relationship, known as Fox's law:

MΎg= Σ (ω_l / Ύg_l),

i ω, being the mass fraction of the monomer i in the block under consideration and Tg, being the glass transition temperature of the homopolymer of the monomer i.

Unless otherwise indicated, the Tg values indicated for the first and second blocks in the present patent application are theoretical Tg values.

The difference between the glass transition temperatures of the first and second blocks is generally greater than 20°C, preferably greater than 40°C and better still greater than 60°C.

In the present invention, the expression:

"between ... and ..." means a range of values in which the limits mentioned are excluded, and

"from ... to ..." and "ranging from ... to ..." means a range of values in which the limits are included. The block polymer used according to the invention has a first block with a glass transition temperature (Tg) of greater than or equal to 40°C, for example a Tg ranging from 40 to 150°C, and obtained from at least one (meth)acrylate monomer of formula CH₂ = C(Ri)-COOR₂ in which R-i represents H or a methyl radical, R₂ represents a C₄ to Ci₂ cycloalkyl group; and preferably an isobornyl group.

Preferably, said first block has a Tg of greater than or equal to 60°C, ranging, for example, from 60°C to 140°C, especially ranging from 80°C to 120°C, preferentially ranging from 95 to 1 10°C. The monomers present in the first block of the polymer and the proportions thereof are preferably chosen such that the glass transition temperature of the first block is greater than or equal to 40°C, and especially in accordance with that described previously.

According to a preferred embodiment, the first block of the polymer is obtained from at least one acrylate monomer of formula CH₂=CH-COOR₂ in which R₂ represents a C₄ to Ci₂ cycloalkyl group, and from at least one methacrylate monomer of formula CH₂=C(CH₃)-COOR'₂ in which R'₂ represents a C₄ to Ci₂ cycloalkyl group.

The first block of the polymer may be obtained exclusively with said acrylate monomer and said methacrylate monomer.

The acrylate monomer and the methacrylate monomer used are preferably present in acrylate/methacrylate mass proportions of between 30/70 and 70/30, preferably between 40/60 and 60/40 and in particular between 45/55 and 55/45. The proportion of the first block in the block polymer advantageously ranges from 60% to 80% and better still from 65% to 75% by weight of the polymer.

According to a preferred embodiment, the first block of the polymer is obtained by polymerization of isobornyl methacrylate and isobornyl acrylate.

The first block of the polymer may also comprise an additional monomer chosen from linear or branched C₈-C₂2 alkyl (meth)acrylates (i.e. comprising a C₈-C₂2 alkyl group), for instance 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, behenyl acrylate, behenyl methacrylate, stearyl acrylate and stearyl methacrylate.

Said additional monomer may be present in a content ranging from 0.1 % to 15% by weight and preferably ranging from 0.1 % to 5%, relative to the total weight of the monomers of the first block of said block polymer.

According to one embodiment, the first block of said block polymer does not contain any additional monomer.

The block polymer used according to the invention has a second block with a glass transition temperature (Tg) of less than or equal to 20°C, for example a Tg ranging from -100 to 20°C, and is obtained from at least one maleic anhydride monomer and from at least one (meth)acrylate monomer of formula CH₂ = C(Ri)-COOR₃ in which R-i represents H or a methyl radical, R₃ representing a linear or branched Ci to C₆

unsubstituted alkyl group, with the exception of a tert-butyl group or a methoxyethyl group. Preferably, said second block has a Tg of less than or equal to 10°C, especially ranging from -80°C to 10°C and better still less than or equal to 0°C, for example ranging from -100°C to 0°C, especially ranging from -30°C to 0°C.

The monomers present in the second block of the polymer and the proportions thereof are preferably chosen such that the glass transition temperature of the second block is less than or equal to 20°C, and especially in accordance with that described previously.

The preferred monomers with a Tg of less than or equal to 20°C are isobutyl acrylate, ethyl acrylate, n-butyl acrylate and methoxyethyl acrylate, or mixtures thereof in all proportions, and preferably isobutyl acrylate.

The second block of the polymer may be obtained exclusively with maleic anhydride and said (meth)acrylate monomer. In the second block, the maleic anhydride and the (meth)acrylate monomer are preferably used in (meth)acrylate/maleic anhydride mass proportions ranging from 1 to 10, preferentially ranging from 2 to 9, especially ranging from 3 to 8 or alternatively ranging from 4 to 7.

The proportion of the second block in the block polymer advantageously ranges from 20% to 40% by weight and better still from 25% to 35% by weight of the polymer.

According to a preferred embodiment, the second block of the polymer is obtained by polymerization of maleic anhydride and isobutyl acrylate.

The second block of the polymer may also comprise an additional silicone monomer of formula (I) (referred to hereinbelow as silicone monomer) below:

in which:

- R₈ denotes a hydrogen atom or a methyl group; preferably methyl;

- R₉ denotes a linear or branched, preferably linear, divalent hydrocarbon-based group containing from 1 to 10 carbon atoms, preferably containing from 2 to 4 carbon atoms, and optionally containing one or two -O- ether bonds; preferably an ethylene, propylene or butylene group;

- R-io denotes a linear or branched alkyl group containing from 1 to 10 carbon atoms, especially from 2 to 8 carbon atoms; preferably methyl, ethyl, propyl, butyl or pentyl;

- n denotes an integer ranging from 1 to 300, preferably ranging from 3 to 200 and preferentially ranging from 5 to 100.

Monomer (I) is a polydimethylsiloxane bearing a mono(meth)methacryloyloxy end group.

Use may be made in particular of monomethacryloyloxypropyl polydimethylsiloxanes such as those sold under the names MCR-M07, MCR-M17, MCR-M1 1 and MCR-M22 by Gelest Inc. or the silicone macromonomers sold under the names X-22-2475, X-22-2426 and X-22-174DX by Shin-Etsu.

Monomer (I) may be present in the second block of the block polymer in a content ranging from 0.1 % to 15% by weight, relative to the total weight of the monomers of the second block of said block polymer, and preferably ranging from 0.1 % to 5%.

According to one embodiment, the second block of said block polymer does not contain any additional monomer. Preferably, the polymer used according to the invention comprises at least, or even consists of, isobornyl acrylate and isobornyl methacrylate monomers in the first block and maleic anhydride and isobutyl acrylate monomers in the second block.

Preferably, the polymer comprises at least, or even consists of, isobornyl acrylate and isobornyl methacrylate monomers in a mass proportion ranging from 30/70 to 70/30 in the first block and isobutyl acrylate and maleic anhydride monomers in the second block. Preferably, the polymer comprises at least, or even consists of, isobornyl acrylate and isobornyl methacrylate monomers in a mass proportion ranging from 40/60 to 60/40 in the first block and isobutyl acrylate and maleic anhydride monomers in the second block.

Preferably, the polymer comprises at least, or even consists of, isobornyl acrylate and isobornyl methacrylate monomers in a mass proportion ranging from 45/55 to 55/45 in the first block and isobutyl acrylate and maleic anhydride monomers in the second block.

Preferably, the polymer comprises at least, or even consists of, isobornyl acrylate and isobornyl methacrylate monomers in a mass proportion ranging from 30/70 to 70/30 in the first block and isobutyl acrylate and maleic anhydride monomers in the second block, the first block representing between 65% and 75% by weight of the polymer, and especially 70% by weight.

Preferably, the polymer comprises at least, or even consists of, isobornyl acrylate and isobornyl methacrylate monomers in a mass proportion ranging from 40/60 to 60/40 in the first block and isobutyl acrylate and maleic anhydride monomers in the second block, the first block representing between 65% and 75% by weight of the polymer, and especially 70% by weight. Preferably, the polymer comprises at least, or even consists of, isobornyl acrylate and isobornyl methacrylate monomers in a mass proportion ranging from 45/55 to 55/45 in the first block and isobutyl acrylate and maleic anhydride monomers in the second block, the first block representing between 65% and 75% by weight of the polymer, and especially 70% by weight.

Preferably, the polymer comprises at least, or even consists of, isobornyl acrylate and isobornyl methacrylate monomers in a mass proportion ranging from 30/70 to 70/30 in the first block and isobutyl acrylate and maleic anhydride monomers in the second block, the first block representing between 65% and 75% by weight of the polymer, and especially 70% by weight, and the maleic anhydride representing from 3% to 7% by weight of the polymer. Preferably, the polymer comprises at least, or even consists of, isobornyl acrylate and isobornyl methacrylate monomers in a mass proportion ranging from 40/60 to 60/40 in the first block and isobutyl acrylate and maleic anhydride monomers in the second block, the first block representing between 65% and 75% by weight of the polymer, and especially 70% by weight, and the maleic anhydride representing from 3% to 7% by weight of the polymer.

Preferably, the polymer comprises at least, or even consists of, isobornyl acrylate and isobornyl methacrylate monomers in a mass proportion ranging from 45/55 to 55/45 in the first block and isobutyl acrylate and maleic anhydride monomers in the second block, the first block representing between 65% and 75% by weight of the polymer, and especially 70% by weight, and the maleic anhydride representing from 3% to 7% by weight of the polymer.

Said first and second blocks of the polymer may be advantageously linked together via an intermediate segment comprising at least one constituent monomer of the first block and at least one constituent monomer of the second block.

The intermediate segment is a block comprising at least one constituent monomer of the first block and at least one constituent monomer of the second block of the polymer, which enables these blocks to be "compatibilized".

Advantageously, the intermediate block comprising at least one constituent monomer of the first block and at least one constituent monomer of the second block of the polymer is a statistical polymer.

Preferably, the intermediate block is derived essentially from constituent monomers of the first block and of the second block.

The term "essentially" means at least 85%, preferably at least 90%, better still 95% and even better still 100%.

Advantageously, the intermediate block has a glass transition temperature Tg that is between the glass transition temperatures of the first and second blocks.

The block polymer used according to the invention is advantageously a film-forming polymer. The term "film-forming polymer" means a polymer that is capable of forming, by itself or in the presence of a film-forming auxiliary agent, a continuous film that adheres to a support, especially to keratin materials.

Advantageously, the block polymer has a polydispersity index of greater than 2.

The polydispersity index I of the polymer is equal to the ratio of the weight-average mass Mw to the number-average mass Mn. The weight-average molar mass (Mw) and number-average molar mass (Mn) are determined by gel permeation liquid chromatography (THF solvent, calibration curve established with linear polystyrene standards, refractometric detector).

The weight-average mass (Mw) of the block polymer is preferably less than or equal to 300 000; it ranges, for example, from 35 000 to 200 000 and better still from 45 000 to 150 000 g/mol.

The number-average mass (Mn) of the block polymer is preferably less than or equal to 70 000; it ranges, for example, from 10 000 to 60 000 and better still from 12 000 to 50 000 g/mol.

Preferably, the polydispersity index of the block polymer is greater than 2, for example ranging from 3 to 1 1 , preferably greater than or equal to 4, for example ranging from 4 to 10.

A subject of the invention is also a process for preparing a block polymer, which consists in mixing, in the same reactor, a polymerization solvent, an initiator, a maleic anhydride monomer, at least one (meth)acrylate monomer of formula CH₂ = C(Ri)-COOR₃ in which Ri represents H or a methyl radical, R₃ represents a linear or branched Ci to C₆ unsubstituted alkyl group, with the exception of a tert-butyl group, or a methoxyethyl group, at least one (meth)acrylate monomer of formula CH₂ = C(Ri)-COOR₂ in which R-i represents H or a methyl radical, R₂ represents a C₄ to Ci₂ cycloalkyl group, according to the following sequence of steps:

- some of the polymerization solvent and some of the initiator are poured into the reactor, and the mixture is heated to a reaction temperature of between 60°C and 120°C,

- said at least one (meth)acrylate monomer of formula CH₂ = C(Ri)-COOR₂ is then poured in, as a first addition, and the mixture is left to react for a time T corresponding to a maximum degree of conversion of said monomers of 90%,

- further polymerization initiator, the maleic anhydride monomer and said

(meth)acrylate of formula CH₂ = C(Ri)-COOR₃ are then poured into the reactor, as a second addition, and the mixture is left to react for a time T' after which the degree of conversion of said monomers reaches a plateau,

- the reaction mixture is cooled to room temperature. The term "polymerization solvent" means a solvent or a mixture of solvents. The polymerization solvent may be chosen especially from ethyl acetate, butyl acetate, C₈-Ci₆ branched alkanes such as C₈-Ci₆ isoalkanes, for instance isododecane, isodecane and isohexadecane, and mixtures thereof. Preferably, the polymerization solvent is isododecane. According to another embodiment, a subject of the invention is a process for preparing a polymer, which consists in mixing, in the same reactor, a polymerization solvent, an initiator, a maleic anhydride monomer, at least one (meth)acrylate monomer of formula CH₂ = C(Ri)-COOR₃ in which R-i represents H or a methyl radical, R₃ represents a linear or branched Ci to C₆ unsubstituted alkyl group, with the exception of a tert-butyl group, or a methoxyethyl group, at least one (meth)acrylate monomer of formula CH₂ = C(R-i)- COOR₂ in which R-i represents H or a methyl radical, R₂ represents a C₄ to C-|₂ cycloalkyl group, according to the following sequence of steps:

- some of the polymerization solvent and some of the initiator are poured into the reactor, and the mixture is heated to a reaction temperature of between

60°C and 120°C,

- the maleic anhydride monomer and said (meth)acrylate of formula CH₂ =

C(Ri)-COOR₃ are then poured in, as a first addition, and the mixture is left to react for a time T corresponding to a maximum degree of conversion of said monomers of 90%,

- further polymerization initiator and said (meth)acrylate monomer of formula

CH₂ = C(Ri)-COOR₂ are then poured into the reactor, as a second addition, and the mixture is left to react for a time T' after which the degree of conversion of said monomers reaches a plateau,

- the reaction mixture is cooled to room temperature.

The polymerization temperature is preferably between 85 and 95°C, especially about 90°C. The reaction time after the second addition is preferably between 3 and 6 hours.

The monomers used in the context of this process, and the proportions thereof, may be those described previously. The polymerization is especially performed in the presence of a radical initiator especially of peroxide type (for example tert-butyl peroxy-2-ethylhexanoate: Trigonox 21 S; 2,5- dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane:Trigonox 141 ; tert-butyl peroxypivalate: Trigonox 25C75 from AkzoNobel) or of azo type, for example (AIBN: azobisisobutyronitrile; V50: 2,2'-azobis(2-amidinopropane) dihydrochloride).

A subject of the invention is also, as novel polymer, the block polymer described previously.

The block polymer used according to the invention may be used in a composition comprising a physiologically acceptable medium, in particular in a cosmetic composition. The term "physiologically acceptable medium" means a medium that is compatible with human keratin fibres, in particular with the hair.

The term "cosmetic composition" is understood to mean a composition that is compatible with keratin materials, which has a pleasant colour, odour and feel and which does not cause unacceptable discomfort (stinging, tautness or redness) liable to discourage the consumer from using it.

The maleic anhydride block polymer as defined previously may be present in the composition used according to the invention, derived from the mixture described previously (extemporaneous mixture), in a content ranging from 0.1 % to 40% by weight, relative to the total weight of the composition derived from the extemporaneous mixture, preferably from 0.5% to 35% by weight, preferentially ranging from 1 % to 30% by weight and more preferentially ranging from 10% to 30% by weight.

A subject of the invention is also a composition comprising said block polymer, especially in a physiologically acceptable medium.

The process according to the invention uses a liposoluble polyol compound.

The term "liposoluble polyol" means a polyhydroxylated compound that is soluble or miscible to at least 1 % by weight in isododecane at 25°C.

The polyol used in the process according to the invention is an organic compound comprising at least two alcohol functions (i.e. two hydroxyl groups). This compound may comprise other unreactive chemical functions such as ester, amide, ketone or urethane functions.

It is possible to use a mixture of different polyols.

According to a first embodiment of the invention, the polyol compound is a

non-polymeric organic compound of formula (II):

W(OH)_n (II) in which n denotes an integer greater than or equal to 2, preferably between 2 and 10, preferably between 2 and 5 (limits inclusive)

and W denotes a linear or branched or (hetero)cyclic, saturated or unsaturated C₈-C₃o multivalent (at least divalent) radical, W also possibly bearing one or more functions chosen from ether, thioether, ester, ketone and amide functions.

The term "non-polymeric compound" means a compound which is not directly obtained via a monomer polymerization reaction The polyol compound is preferably a diol compound. Preferably, W denotes a C₈-Ci₈ multivalent radical, which is especially linear.

Preferentially, the liposoluble polyol is a C₈-Ci₈ diol, which is especially linear. Advantageously, the C₈-Ci₈ chain is a hydrocarbon-based chain (formed from carbon and hydrogen).

In particular, the liposoluble polyol is a C₈-Ci₆ and especially C10-C14 linear diol.

As polyol of formula (II), mention may be made of 1 ,8-octanediol, 1 ,10-decanediol, 1 ,12- dodecanediol, 1 ,14-tetradecanediol, 1 ,16-hexadecanediol and 1 ,18-octadecanediol.

1 ,10-Decanediol, 1 ,12-dodecanediol or 1 ,14-tetradecanediol is preferably used. 1 ,12- Dodecanediol is preferentially used.

According to a second embodiment of the invention, the polyol compound is a polymeric compound of formula (II): POL(OH)_m (lll) in which n denotes an integer greater than or equal to 2, and POL denotes a carbon- based or silicone polymeric radical, POL also possibly containing one or more heteroatoms such as O, N or S, and/or one or more functions chosen from ester, ketone, amide, urea and carbamate functions, and/or possibly being substituted with one or more linear or branched C1-C10 alkyl or linear or branched C1-C10 alkoxy groups, it being understood that, when POL is substituted, the hydroxyl functions may be borne by the substituent(s). The weight-average molecular weight of the compounds of formula (III) is generally between 500 and 400 000 and preferably between 500 and 150 000.

Preferably, the polyol polymers may be polymeric diols, especially polyolefin diols, polydimethylsiloxane diols or polyester diols.

The polyolefin diols may be polydienes bearing hydroxyl end groups, for instance those described in FR-A-2 782 723. They may be chosen from diols derived from polybutadiene, polyisoprene and poly(1 ,3-pentadiene) homopolymers and copolymers. Preferably, they have a number-average molecular mass (Mn) of less than 7000, preferably between 1000 and 5000. Mention will be made in particular of the hydroxylated polybutadienes sold by Cray Valley under the brand names Poly BD R45 HTLO, Poly BD R45V and Poly BD R-20 LM, which will preferably be used hydrogenated; and also hydrogenated di hydroxylated (1 ,2-polybutadienes), such as GI3000 of Mn = 3100, GI2000 (Mn = 2100) and GI 1000 (Mn = 1500) sold by the company Nisso. Among the polyolefins with hydroxyl end groups, mention may be made preferentially of polyolefins, homopolymers or copolymers with α,ω-hydroxyl end groups, such as polyisobutylenes with α,ω-hydroxyl end groups; and the copolymers of formula:

especially those sold by Mitsubishi under the brand name Polytail.

Hydrogenated polybutadiene diols are preferably used.

The polydimethylsiloxane diols may be those of formula (IV):

in which:

R1 = divalent C₂-C₆ alkylene group

X = covalent bond or group -0-R₂- with R₂ = C₂-C₆ alkylene

n = 1 to 100, preferably 5 to 50 and preferentially from 10 to 30. The polydimethylsiloxane diols used may be those sold under the names KF-6000, KF- 6001 , KF-6002 and KF-6003 by the company Shin-Etsu Chemicals.

The polydimethylsiloxane diol preferably used is that of formula (IVa):

Use may also be made of dimethiconols, which are polydimethylsiloxanes bearing OH end functions. An example that may be mentioned is the product sold under the name Xiameter PMX-1502 Fluid by the company Dow Corning. The polyester diols may be chosen from those derived from the condensation reaction of a C₈-C₃o and preferably C₈-Ci₈ diol, such as 1 ,8-octanediol, 1 ,9-nonanediol, 2-methyl-1 ,8- octanediol, 1 ,10-decadediol, 1 ,12-dodecanediol, 1 ,14-tetradecadediol, 1 ,16- hexadecanediol and 1 ,18-octadecanediol;

and of a C₄-Ci₂ carboxylic acid such as phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, trimellitic acid, azelaic acid, succinic acid or glutaric acid. Polyester polyols are especially described in patents US 6 136 880 and EP 0 960 355. Examples of polyester diols that may be mentioned include 1 ,9-nonanediol/adipic acid copolymers such as those sold under the name Kurapol N-2010 by the company Kuraray. The polyester polyols are preferably chosen from the hydrogenated polybutadiene diols and polydimethylsiloxane diols of formula (IV) or (IVa) described previously.

Advantageously, the liposoluble polyol compound is used in a mole ratio OH group of the liposoluble polyol/maleic anhydride group of the acrylic polymer ranging from 0.01 to 10, preferably ranging from 0.1 to 5, preferentially ranging from 0.1 to 2 and more preferentially ranging from 0.1 to 1.

The polyol compound reacts with the maleic anhydride group present in the block olymer, for example in the following manner:

Such a crosslinked polymer is novel and thus also forms the subject of the present invention. The crosslinked polymer may thus be obtained by reacting said liposoluble polyol compound with the maleic anhydride acrylic polymer described previously, especially in the presence of said amine catalyst. Some or all of the anhydride groups react with the OH group of the polyol compound and form a unit bearing an ester group and a carboxylic acid group as described previously.

The amine catalyst used in the process according to the invention may be chosen from catalysts bearing a primary amine function or bearing an aminidine function or bearing a guanidine function. The catalyst bearing a tertiary amine function may be chosen from triethylamine, diisopropylethylamine, tri-n-propylamine, tri-n-butylamine, methyldibutylamine, N- methyldicyclohexylamine, Ν,Ν-dimethylcyclohexylamine, ethyldiisopropylamine, N,N- diethylcyclohexylamine, pyridine, 4-dimethylaminopyridine, N-methylpiperidine, N- ethylpiperidine, N-n-butylpiperidine, 1 ,2-dimethylpiperidine, N-methylpyrrolidine, 1 ,2- dimethylpyrrolidine, dimethylaniline, picoline, Ν,Ν-dimethylbenzylamine, bis(2- dimethylaminoethyl) ether, Ν,Ν,Ν',Ν',Ν''-pentamethyldiethylenetriamine, Ν,Ν,Ν',Ν'- tetramethylethylenediamine, N-methylmorpholine, N-ethylmorpholine and 1 ,4- diazabicyclo[2.2.2]octane, and mixtures thereof.

Diisopropylethylamine is preferably used.

The catalysts bearing an aminidine function are, for example, 1 ,5-diazabicyclo[4.3.0]non- 5-ene (or DBN) and 1 ,8-diazabicyclo[5.4.0]undec-7-ene (or DBU). The catalysts bearing a guanidine function may be chosen from the compounds of formula (V) below:

(V) in which R1 , R2, R3, R4 and R5 independently represent a hydrogen atom or a linear or branched C1 -C4 lower alkyl or alkenyl radical,

when R1 , R2 and R3 and R4 represent a hydrogen atom, R5 may also denote a radical from the following: acetyl; carboxamide; methoxy; ethoxy; 1 ,2,4-triazolyl; cyclopentyl; methoxycarbonyl; ethoxycarbonyl; phenyl; benzyl; thiazolidone; benzimidazole; benzoxazole; benzothiazole; or C(=NH)-NR6R7 in which R6 and R7 denote, independently of each other, a hydrogen atom or a linear or branched C1 -C4 lower alkyl radical; or else a phenyl radical,

when R1 =R2=R3=H, R4 and R5 may also form, with the nitrogen atom that bears them, a pyrrolidine, piperidine, pyrazole or 1 ,2,4-triazole ring,

when R1 =R2=H, and R4=H or methyl, R3 and R5 may also together form a 5-membered ring optionally containing an oxo group,

and the organic or mineral salts thereof.

Salts that may be mentioned include the hydrochloride, sulfate, sulfamate, carbonate, bicarbonate, phosphate and acetate salts.

Among the compounds of formula (V), mention may be made especially of the following compounds: guanidine, aminoguanidine, 1 -acetylguanidine, guanylurea, phenylguanidine, 1 ,1 - dimethylguanidine, 1 -ethylguanidine, 1 ,1 -diethylguanidine, creatine, agmatine, biguanide, N-methyl biguanide, N-ethyl biguanide, N-propyl biguanide, N-butylbiguanide, 1 ,1 - dimethylbiguanide, 1 -phenylbiguanide, 1 ,1 ,3,3-tetramethylguanidine, 2-tert-butyl-1 , 1 ,3,3- tetramethylguanidine, 1 H-pyrazole-1 -carboxamidine, 5-hydroxy-3-methyl-1 H-pyrazole-1 - carboximidamide, 3,5-diamino-1 H-1 ,2,4-triazole-1 -carboximidamide, 2-guanidone-4- thiazolidone, 2-guanidinobenzimidazole, 2-guanidinobenzoxazole, 2- guanidinobenzothiazole, 1 ,1 ,3,3-tetramethylguanidine (or TMG), 1 ,5,7- triazabicyclo[4.4.0]dec-5-ene (or TBD), 7-methyl-1 ,5,7-triazabicyclo[4.4.0]dec-5-ene (or MTBD).

The amine catalyst may be present in a content ranging from 0.1 % to 0.5% by weight and preferably ranging from 0.1 % to 0.2% by weight relative to the total weight of the composition derived from the mixture described previously (extemporaneous mixture).

The process for treating keratin fibres, in particular human keratin fibres such as the hair, comprises:

(i) a step of applying to keratin fibres an (extemporaneous) mixture of the maleic anhydride block polymer, or of a cosmetic composition comprising it, of the liposoluble polyol compound or of a cosmetic composition containing it, and of the amine catalyst as defined previously;

steps (i) and (ii) being performed simultaneously or separately, in the order: step (i) and then step (ii).

According to one embodiment of the process according to the invention, the mixing of the composition comprising the maleic anhydride block polymer and of the liposoluble polyol, or of the composition containing it, and of the amine catalyst is performed in a time of between 1 minute and 24 hours before application to the keratin fibres, and preferably between 5 and 30 minutes.

The process according to the invention comprises a step (ii) of heating the keratin fibres to a temperature ranging from 90°C to 250°C, preferably ranging from 100 to 230°C. Preferably, the step of heating the keratin fibres is performed at a temperature ranging from 170 to 250°C, preferably ranging from 180°C to 240°C, preferentially ranging from 190°C to 230°C and especially ranging from 200°C to 230°C.

This heating step is advantageously performed using an iron.

The heating step is necessary to optimize the effects of the process. For the purposes of the present invention, the term "iron" means a device for heating keratin fibres by placing said fibres and the heating device in contact with each other. The end of the iron which comes into contact with the keratin fibres generally has two flat surfaces. These two surfaces may be made of metal or ceramic. In particular, these two surfaces may be smooth or crimped or curved.

The heating step may be performed by means of a straightening iron, a curling iron or a crimping iron. Preferably, the heating step is performed using a straightening iron.

As examples of irons that may be used in the heating process according to the invention, mention may be made of any type of flat iron, and in particular, in a nonlimiting manner, those described in patents US 5 957 140 and US 5 046 516.

The iron may be applied by successive separate strokes lasting a few seconds or by gradual movement or sliding along the locks of keratin fibres, especially of human keratin fibres such as the hair.

Preferably, the iron is applied in the process according to the invention by a continuous movement from the root to the tip of the hair, in one or more passes, in particular in two to twenty passes. The duration of each pass of the iron may last from 2 seconds to 1 minute.

The process according to the invention may also comprise an additional step of drying the keratin fibres after step (i) of applying the block polymer or the cosmetic composition containing it and before step (ii) of heating the keratin fibres performed at a temperature ranging from 90°C to 250°C. The drying step may be performed using a hairdryer or a hood or by leaving the keratin fibres to dry naturally. The drying step is advantageously performed at a temperature ranging from 20 to 70°C.

After the heating step, the keratin fibres may be optionally rinsed with water or washed with a shampoo. The keratin fibres are then optionally dried using a hairdryer or a hood or in the open air.

According to one embodiment, the process according to the invention is performed on natural or damaged or sensitized keratin fibres, which have optionally been dyed and/or have optionally undergone a prior long-lasting or temporary hair shaping treatment.

Damaged fibres are, for example, dry or coarse or brittle or split or soft fibres.

Sensitized fibres are, for example, bleached, relaxed or permanent-waved fibres. The process according to the invention is preferably performed on dry keratin fibres, i.e. fibres that are not wet, especially dry hair. After step (i) of applying to the keratin fibres the block polymer or a cosmetic composition containing it, and before performing step (ii) of heating the keratin fibres, the block polymer or the composition containing it may be left on the fibres after application for a time ranging from 1 to 60 minutes, preferably ranging from 2 to 50 minutes and preferentially ranging from 5 to 45 minutes. The leave-on time may take place at a temperature ranging from 15°C to 45°C, preferably at room temperature (25°C). The composition described previously is advantageously applied to the keratin fibres in an amount ranging from 0.1 to 10 grams and preferably from 0.2 to 5 grams of composition per gram of keratin fibres.

After application of the composition to the keratin fibres, they may be drained to remove the excess composition.

The treatment process according to the invention may be performed during and/or after, preferably after, an additional process of cosmetic treatment of the keratin fibres, such as a process for temporary hair shaping (hair shaping with curlers, a curling iron or a straightening iron) or a process for durable hair shaping (permanent-waving or relaxing) or a process for dyeing or bleaching the keratin fibres.

The treatment process according to the invention may also be performed as a post- treatment to a cosmetic treatment process.

In particular, the treatment process is performed as a post-treatment to a dyeing, bleaching or relaxing process and/or a permanent-waving process.

According to the process according to the invention, mixing, especially extemporaneous mixing, of the maleic anhydride block polymer, the liposoluble polyol compound and the amine catalyst is performed, and the mixture is applied to the keratin fibres, in particular to the hair.

The composition used according to the invention is generally suitable for topical application to keratin fibres, and thus generally comprises a physiologically acceptable medium, i.e. a medium that is compatible with the skin and/or its integuments. It is preferably a cosmetically acceptable medium, i.e. a medium which has a pleasant colour, odour and feel and which does not cause any unacceptable discomfort (stinging, tautness or redness) liable to discourage the consumer from using this composition.

According to a preferred embodiment of the invention, the composition comprising the maleic anhydride block polymer may contain a hydrocarbon-based oil.

The hydrocarbon-based oil is an oil that is liquid at room temperature (25°C). The term "hydrocarbon-based oil" means an oil formed essentially from, or even constituted of, carbon and hydrogen atoms, and optionally oxygen and nitrogen atoms, and not containing any silicon or fluorine atoms. It may contain alcohol, ester, ether, carboxylic acid, amine and/or amide groups.

The hydrocarbon-based oil may be volatile or non-volatile. Preferably, the hydrocarbon- based oil is volatile.

The hydrocarbon-based oil may be chosen from:

hydrocarbon-based oils containing from 8 to 14 carbon atoms, and especially:

- branched C₈-Ci₄ alkanes, for instance C₈-Ci₄ isoalkanes of petroleum origin (also known as isoparaffins), for instance isododecane (also known as 2,2,4,4,6-pentamethylheptane), isodecane and, for example, the oils sold under the trade name Isopar or Permethyl,

- linear alkanes, for instance n-dodecane (C12) and n-tetradecane (C14) sold by Sasol under the respective references Parafol 12-97 and Parafol 14-97, and also mixtures thereof, the undecane-tridecane mixture, the mixtures of n-undecane (C1 1 ) and of n- tridecane (C13) obtained in Examples 1 and 2 of patent application WO 2008/155 059 from the company Cognis, and mixtures thereof, - short-chain esters (containing from 3 to 8 carbon atoms in total) such as ethyl acetate, methyl acetate, propyl acetate or n-butyl acetate,

- hydrocarbon-based oils of plant origin such as triglycerides constituted of fatty acid esters of glycerol, the fatty acids of which may have chain lengths varying from C₄ to C₂₄, these chains possibly being linear or branched, and saturated or unsaturated; these oils are especially heptanoic or octanoic acid triglycerides, or alternatively wheatgerm oil, sunflower oil, grapeseed oil, sesame oil, corn oil, apricot oil, castor oil, shea oil, avocado oil, olive oil, soybean oil, sweet almond oil, palm oil, rapeseed oil, cottonseed oil, hazelnut oil, macadamia oil, jojoba oil, alfalfa oil, poppy oil, pumpkin oil, marrow oil, blackcurrant oil, evening primrose oil, millet oil, barley oil, quinoa oil, rye oil, safflower oil, candlenut oil, passion-flower oil and musk rose oil; shea butter; or else caprylic/capric acid triglycerides, for instance those sold by the company Stearineries Dubois or those sold under the names Miglyol 810^®, 812^® and 818^® by the company Dynamit Nobel, - synthetic ethers having from 10 to 40 carbon atoms;

- linear or branched hydrocarbons of mineral or synthetic origin, such as petroleum jelly, polydecenes, hydrogenated polyisobutene such as Parleam®, squalane and liquid paraffins, and mixtures thereof, - synthetic esters such as oils of formula R₁COOR₂ in which R-i represents a linear or branched fatty acid residue containing from 1 to 40 carbon atoms and R₂ represents an, in particular, branched hydrocarbon-based chain containing from 1 to 40 carbon atoms, on condition that R-i + R₂ >10, for instance purcellin oil (cetostearyl octanoate), isopropyl myristate, isopropyl palmitate, Ci₂ to Ci₅ alcohol benzoates, hexyl laurate, diisopropyl adipate, isononyl isononanoate, 2-ethylhexyl palmitate, isostearyl isostearate, 2- hexyldecyl laurate, 2-octyldecyl palmitate, 2-octyldodecyl myristate, alcohol or polyalcohol heptanoates, octanoates, decanoates or ricinoleates such as propylene glycol dioctanoate; hydroxylated esters such as isostearyl lactate, diisostearyl malate and 2- octyldodecyl lactate; polyol esters and pentaerythritol esters,

- fatty alcohols that are liquid at room temperature, with a branched and/or unsaturated carbon-based chain containing from 12 to 26 carbon atoms, for instance octyldodecanol, isostearyl alcohol, oleyl alcohol, 2-hexyldecanol, 2-butyloctanol and 2- undecylpentadecanol,

Advantageously, the hydrocarbon-based oil is apolar (thus formed solely from carbon and hydrogen atoms). The hydrocarbon-based oil is preferably chosen from hydrocarbon-based oils containing from 8 to 14 carbon atoms, in particular the apolar oils described previously.

Preferentially, the hydrocarbon-based oil is isododecane. The composition comprising the polymer may contain, in addition to the hydrocarbon- based oil, a silicone oil. The term "silicone oil" means an oil comprising at least one silicon atom and especially at least one Si-0 group. The silicone oil may be volatile or nonvolatile.

The term "volatile oil" means an oil (or non-aqueous medium) that is capable of evaporating on contact with the skin in less than one hour, at room temperature and at atmospheric pressure. The volatile oil is a volatile cosmetic oil, which is liquid at room temperature, especially having a non-zero vapour pressure, at room temperature and at atmospheric pressure, in particular having a vapour pressure ranging from 0.13 Pa to 40 000 Pa (10^"3 to 300 mmHg), preferably ranging from 1 .3 Pa to 13 000 Pa (0.01 to 100 mmHg) and preferentially ranging from 1.3 Pa to 1300 Pa (0.01 to 10 mmHg).

The term "non-volatile oil" means an oil with a vapour pressure of less than 0.13 Pa.

Volatile silicone oils that may be mentioned include volatile linear or cyclic silicone oils, especially those with a viscosity < 8 centistokes (cSt) (8 ^χ 10^"6 m²/s), and especially having from 2 to 10 silicon atoms and in particular from 2 to 7 silicon atoms, these silicones optionally comprising alkyl or alkoxy groups having from 1 to 10 carbon atoms. As volatile silicone oils that may be used in the invention, mention may be made especially of dimethicones with viscosities of 5 and 6 cSt, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, heptamethylhexyltrisiloxane, heptamethyloctyltrisiloxane, hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane and dodecamethylpentasiloxane, and mixtures thereof.

As non-volatile silicone oils, mention may be made of linear or cyclic non-volatile polydimethylsiloxanes (PDMSs); polydimethylsiloxanes comprising alkyl, alkoxy or phenyl groups, which are pendent or at the end of a silicone chain, these groups containing from 2 to 24 carbon atoms; phenyl silicones, for instance phenyl trimethicones, phenyl dimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyl dimethicones, diphenylmethyldiphenyltrisiloxanes and 2-phenylethyl trimethylsiloxysilicat.es. Advantageously, the composition may comprise a hydrocarbon-based oil in a content ranging from 60% to 100% by weight relative to the total weight of the oils present in the composition and from 0 to 40% by weight of silicone oil. According to a preferred embodiment of the invention, the composition contains as oil only a hydrocarbon-based oil. Preferentially, the hydrocarbon-based oil is volatile.

The composition according to the invention may comprise a cosmetic additive chosen from fragrances, preserving agents, fillers, UV-screening agents, oils, waxes, surfactants, moisturizers, vitamins, ceramides, antioxidants, free-radical scavengers, polymers, thickeners, dyestuffs and antidandruff active agents.

According to one embodiment, the composition according to the invention is an anhydrous composition. The term "anhydrous composition" means a composition containing less than 2% by weight of water, or even less than 0.5% of water, and is especially free of water. Where appropriate, such small amounts of water may especially be introduced by ingredients of the composition that may contain residual amounts thereof.

Needless to say, those skilled in the art will take care to select this or these optional additional compounds, and/or the amount thereof, such that the anti-wrinkle properties of the composition according to the invention are not, or are not substantially, adversely affected by the envisaged addition.

The invention will now be described with reference to the following examples, which are given as non-limiting illustrations. Example 1 : Isobornyl methacrylate/isobornyl acrylate (35/35 by weight)-co-isobutyl acrylate/maleic anhydride (25/5 by weight) copolymer

1 litre of isododecane was placed in a jacketed 1 -litre reactor equipped with a stirring anchor and the temperature was then increased from 25°C to 90°C over 1 hour.

105 g of isobornyl methacrylate, 105 g of isobornyl acrylate and 1 .8 g of 2,5-bis(2- ethylhexanoylperoxy)-2,5-dimethylhexane (Trigonox® 141 from Akzo Nobel) were then added over 1 hour. The reaction mixture was stirred for 1 hour 30 minutes at 90°C.

75 g of isobutyl acrylate, 15 g of maleic anhydride and 1 .2 g of 2,5-bis(2- ethylhexanoylperoxy)-2,5-dimethylhexane were then added over 30 minutes.

The reaction mixture was stirred for 3 hours at 90°C and was then cooled to room temperature (25°C) and diluted by adding 150 g of isododecane.

A solution containing 50% polymer active material in isododecane was thus obtained. The polymer obtained has a number-average molecular weight (Mn) of 18 000 and a weight-average molecular weight (Mw) of 290 200; with an Ip = 8.9.

Comparative Examples 2 to 7:

The six compositions described below were prepared.

For each composition, all the ingredients were mixed at the same time at room temperature (25°C) in a glass flask and the composition was then heated at 150°C using a multi-well stirrer for 10 minutes. The state of the composition was then observed by turning the flask upside-down to thus determine whether the mixture had reacted with a crosslinking reaction of the polymer (crosslinking inducing an increase in the viscosity of the initial mixture).

The following results were obtained

Example 2 Example 3 Example 4

Polymer of Example 1 25% AM 25% AM 25% AM

Diol 1 10 % 10% 10%

Diisopropylethylamine 0% 0.15% 0.5%

Isododecane qs 100% qs 100% qs 100%

State of the Fluid Fluid but slightly Viscous; flows composition viscous partly, remaining on the walls of the flask

Diol 1 : hydrogenated dihydroxylated polybutene GI-1000 from Nisso (hydroxyl number: 60-75 KOH mg/number-average = number-average molecular weight = 1500)

Diol 2 : PDMS-OH KF-6001 from Shin-Etsu (hydroxyl number = 62 mg KOH/g; viscosity at 25°C = 45 mm²/s)

The results obtained show that the compositions according to the invention (Examples 3, 4, 6, 7) thickened after heating, which proves that the crosslinking reaction of the polymer with the diol has indeed taken place.

The same test performed without performing the heating step for 10 minutes at 150°C, leads to compositions that are all fluid: without the heating step, crosslinking of the polymer does not take place.

Comparative Examples 8 to 10:

The following three compositions were prepared:

Diol 3: 1 ,12-Dodecanediol

Locks of hair were treated according to the following protocol:

2.7 g locks of natural Caucasian hair were used.

The locks were washed with Ultra Doux camomile shampoo (from La Scad) by applying 1 .2 g of shampoo to a lock of wet hair. The lock was then rinsed, then drained, then dried under a hood at 60°C for 10 minutes. 5.4 g of the test composition were then applied to the lock of hair. The lock was then dried at 60°C (under a code) for 15 minutes, and a straightening iron heated to 210°C was then applied for 15 minutes by making 15 sweeps along the length of the lock (each sweep lasting about 4 seconds). The fixing quality of the lock was evaluated.

Washing with water was then performed by immersing the treated lock of hair in water (at room temperature, 25°C) for 5 minutes. The lock was then drained and then dried under a hood at 60°C for 15 minutes. The fixing quality of the lock of hair was again evaluated. The lock was then combed by passing the comb through it 8 times, and the fixing quality was re-evaluated.

For comparison of the effect of the heating step performed with the curling iron heated to 210°C, the same protocol is performed on another lock of hair, but without performing the application of the curling iron. The fixing quality of the lock of hair was evaluated by observing the more or less rigid appearance of the lock: the lock is taken by one of its ends with the fingers and turned upside-down, holding it at the bottom; the shape of the lock is then observed; either the lock retains its shape, which means that the lock is fixed very well; or the lock becomes deformed (under the effect of gravity) which means that the lock is not fixed very well.

The fixing quality of the lock of hair was evaluated according to the following grading.

Lock without fixing: - Lock with weak fixing: +

Lock with moderate fixing: ++

Lock with very good fixing: +++

The following results were obtained:

Example Example Example Example Example Example 8 with 8' 9 with 9' 10 with 10" heat without heat without heat without heat heat heat

Fixing +++ + +++ + +++ + before

washing

Fixing ++ ++ ++ + after

washing

Fixing + - + - + - after combing

The results obtained show that the locks of Examples 8, 9 and 10 treated via the process according to the invention have good fixing properties before and after washing with water, and also after combing. These properties are superior to those of the locks of Examples 8', 9' and 10' which did not undergo a heating step with the curling iron.

Claims

1 . Cosmetic process for treating keratin fibres, comprising:

(i) a step of applying to the keratin fibres a mixture (extemporaneous) of a maleic anhydride block polymer, or of a cosmetic composition comprising it, of a liposoluble polyol compound or of a cosmetic composition containing it, and of an amine catalyst; said block polymer comprising:

steps (i) and (ii) being performed at the same time or separately, in the order (i) and then (ii).

2. Process according to Claim 1 , characterized in that the first block of the block polymer is obtained from at least one acrylate monomer of formula CH₂=CH-COOR₂ in which R₂ represents a C₄ to Ci₂ cycloalkyl group, and from at least one methacrylate monomer of formula CH₂=C(CH₃)-COOR'₂ in which R'₂ represents a C₄ to Ci₂ cycloalkyl group;

and optionally an additional monomer chosen from linear or branched C₈-C₂₂ alkyl (meth)acrylates.

3. Process according to the preceding claim, characterized in that for the first block of the block polymer, said acrylate monomer and said methacrylate monomer are in acrylate/methacrylate mass proportions of between 30/70 and 70/30, preferably between 40/60 and 60/40, especially between 45/55 and 55/45.

4. Process according to either of Claims 2 and 3, characterized in that the first block of the block polymer is obtained by polymerization of isobornyl methacrylate and isobornyl acrylate.

5. Process according to any one of the preceding claims, characterized in that the proportion of the first block in the block polymer ranges from 60% to 80% and better still from 65% to 75% by weight of the polymer.

6. Process according to any one of the preceding claims, characterized in that the second block of the block polymer comprises a monomer chosen from isobutyl acrylate, ethyl acrylate, n-butyl acrylate and methoxyethyl acrylate, or mixtures thereof, and preferably isobutyl acrylate.

7. Process according to any one of the preceding claims, characterized in that, for the second block of the block polymer, the maleic anhydride and said (meth)acrylate monomer are in maleic anhydride/(meth)acrylate mass proportions ranging from 1 to 10, preferentially ranging from 2 to 9, especially ranging from 3 to 8, or alternatively ranging from 4 to 7.

8. Process according to any one of the preceding claims, characterized in that the second block of the block polymer comprises an additional silicone monomer of formula (I):

in which:

- R₈ denotes a hydrogen atom or a methyl group; preferably methyl;

9. Process according to any one of the preceding claims, characterized in that the proportion of the second block in the block polymer ranges from 20% to 40% by weight and better still from 25% to 35% by weight of the polymer.

10. Process according to one of the preceding claims, characterized in that said block polymer comprises an intermediate segment comprising at least one constituent monomer of the first block and at least one constituent monomer of the second block, and is especially a statistical polymer.

1 1 . Process according to one of the preceding claims, characterized in that said block polymer has a polydispersity index of the block polymer of greater than 2, preferably ranging from 3 to 1 1 .

12. Process according to one of the preceding claims, characterized in that the maleic anhydride block polymer is present in the composition applied to the keratin materials in a content ranging from 0.1 % to 40% by weight, relative to the total weight of the composition derived from the extemporaneous mixture, preferably from 0.5% to 35% by weight, preferentially ranging from 1 % to 30% by weight and more preferentially ranging from 10% to 30% by weight.

13. Process according to one of the preceding claims, characterized in that the

liposoluble polyol is a non-polymeric organic compound of formula (II):

W(OH)_n (II) in which n denotes an integer greater than or equal to 2, preferably between 2 and 10, preferably between 2 and 5,

W denotes a linear or branched or (hetero)cyclic, saturated or unsaturated C₈-C₃o multivalent radical, W also possibly one or more functions chosen from ether, thioether, ester, ketone and amide functions.

14. Process according to one of the preceding claims, characterized in that the liposoluble polyol is a diol bearing a C₈-Ci₈ hydrocarbon-based chain, chosen especially from 1 , 10- decanediol, 1 , 12-dodecanediol and 1 , 14-tetradecanediol, and preferentially 1 ,12- dodecanediol.

15. Process according to one of the preceding claims, characterized in that the polyol is chosen from polyolefin diols, polydimethylsiloxane diols and polyester diols,

preferably chosen from hydrogenated polybutadiene diols, and the polydimethylsiloxane diols of formula (IV):

CH CH. CH,

3 I I ³

HO-X-Si-O-hSi-O-HSi-X-OH

I I I C^{Hs CHs CHs} (IV)

in which:

R1 = divalent C₂-C₆ alkylene group

X = covalent bond or group -0-R₂- with R₂ = C₂-C₆ alkylene

n = 1 to 100, preferably 5 to 50 and preferentially from 10 to 30,

preferably,

16. Process according to one of the preceding claims, characterized in that the

liposoluble polyol is used in a mole ratio of OH group of the liposoluble polyol/maleic anhydride group of the acrylic polymer ranging from 0.01 to 10, preferably ranging from 0.1 to 5, preferentially ranging from 0.1 to 2 and more preferentially ranging from 0.1 to 1.

17. Process according to one of the preceding claims, characterized in that the amine catalyst is chosen from catalysts bearing a primary amine function or bearing an aminidine function or bearing a guanidine function, and is preferably diisopropylethylamine.

18. Process according to one of the preceding claims, characterized in that the amine catalyst is present in a content ranging from 0.1 % to 0.5% by weight and preferably ranging from 0.1 % to 0.2% by weight relative to the total weight of the composition derived from said mixture.

19. Process according to any one of the preceding claims, characterized in that the composition comprises a hydrocarbon-based oil, preferably an apolar hydrocarbon-based oil containing from 8 to 14 carbon atoms, preferentially isododecane.

20. Process according to any one of the preceding claims, characterized in that the mixing of the composition comprising the block polymer of maleic anhydride and of the liposoluble polyol, or of the composition containing it, and of the amine catalyst is performed in a time of between 1 minute and 24 hours before application to the keratin fibres, and preferably between 5 and 30 minutes.

21. Process according to one of the preceding claims, characterized in that the heating step is performed at a temperature ranging from 100 to 230°C, preferably from 190 to 230°C.

22. Process according to one of the preceding claims, characterized in that the heating step is performed with an iron.

23. Process according to one of the preceding claims, characterized in that it comprises an additional step of drying the keratin fibres after step (i) and before step (ii), preferably at a temperature ranging from 20 to 70°C.

24. Kit comprising: a first composition comprising a maleic anhydride block polymer as defined in one of

Claims 1 to 12 and optionally a physiologically acceptable medium, and

a second composition comprising a liposoluble polyol compound as defined in one of

Claims 1 and 13 to 16 and optionally a physiologically acceptable medium,

the first composition or the second composition comprising an amine catalyst as defined in one of Claims 1 , 17 and 18,

the first and second compositions each being packaged in a separate packaging assembly.

25. Cosmetic composition obtained by mixing a maleic anhydride block polymer as defined in one of Claims 1 to 1 1 or a composition containing it and comprising a physiologically acceptable medium, a liposoluble polyol compound as defined in one of Claims 1 and 13 to 16 or a composition containing it and comprising a physiologically acceptable medium, and an amine catalyst as defined in one of Claims 1 , 17 and 18.

26. Polymer that may be obtained by reacting a liposoluble polyol compound as defined in one of Claims 1 and 13 to 16 with a maleic anhydride acrylic polymer as defined in one of Claims 1 to 1 1 .