WO2013190464A2

WO2013190464A2 - Cosmetic process for making up and/or caring for a skin surface

Info

Publication number: WO2013190464A2
Application number: PCT/IB2013/054998
Authority: WO
Inventors: Henri Samain
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2012-06-19
Filing date: 2013-06-18
Publication date: 2013-12-27
Anticipated expiration: 2014-12-19
Also published as: WO2013190464A3

Description

"Cosmetic process for making up and/or caring for a skin surface"

The present invention relates to a cosmetic process for making up and/or caring for the skin, in particular for treating aesthetic skin defects and imperfections.

These imperfections are of various origins and may or may not be age-related.

Thus, skin imperfections may also result from skin imperfections, for instance acne scars, or from the effects of surgical intervention such as scars.

As regards age-related imperfections, wrinkles are manifestly the most representative thereof.

These wrinkles may be categorized as "deep" wrinkles, which are very visible or which may have a depth of 300 microns or more, "medium" wrinkles, which are visible and have a depth ranging between 150 microns and 300 microns, and "shallow" wrinkles, which are less visible than the previous ones and have a depth of less than 150 microns.

It is common practice to seek to camouflage skin imperfections, in particular on the face or the neck, using foundations.

Conventional foundations generally afford substantial coverage and are useful for making the complexion matt and hiding skin colour imperfections, such as redness, but they are not always also suited to hiding relief defects such as wrinkles.

it is also desirable to be able to conceal defects, without generating a mask effect and while maintaining a "natural" render in terms of the makeup effect, for example by creating a skin grain or relief effect.

Finally, users are always in search of novel products that are innovative in terms of the visual effect afforded by the makeup deposit they form.

The object of the present invention is, precisely, to satisfy the abovementioned expectations.

As emerges from the examples presented below, the inventors have discovered that it is possible to satisfy the abovementioned expectations by forming a coating in the form of a set foam via the use of specific photo-erosslinkable compounds.

Thus, according to a first of its aspects, the present invention relates to a cosmetic process for making up and/or caring for a skin surface, comprising at least the steps consisting in:

(i) forming, on the said skin surface, an aerated coat of a composition (M) comprising, in a physiologically acceptable medium, at least one photo-crosslinkable compound, the said compound comprising at least one activated photo-dimerizable group bearing at least one activated double bond; and

(ii) exposing all or part of the surface of the said coat formed in step (i) to conditions favourable for crosslinking the said photo-crosslinkable compound.

The term "physiologically acceptable medium" means a medium free of toxicity, which is compatible with application to human keratin materials, in particular the skin.

The coating formed according to the invention may be more particularly intended for making up and/or caring for a facial skin surface.

The term "aerated" composition means a composition comprising a gaseous phase (for example air) in the form of bubbles. It is also known as a composition "in foam form".

Structures of foam type have already been proposed for cosmetic applications, especially for giving a volume effect. For example, patent applications US 2004/126 345, WO 04/060 292 and WO 04/060 334 disclose the application, to the skin, the lips or keratin fibres such as the hair, of a composition which forms a foam after application, which will be stabilized via the film formation of a film-forming polymer.

However, to the inventors' knowledge, no process has ever been proposed for making up and/or caring for the skin according to the invention, in particular using an aerated composition comprising at least one photo-crosslinkable compound as defined previously,

The process of the invention proves to be advantageous in several respects.

Firstly, it is possible with the aid of the process of the invention to form a coating of controlled thickness on the surface of the skin.

The coating formed on the surface of the skin according to the process of the invention may have, after a single application of aerated composition, a thickness of greater than or equal to 10 μιη, in particular ranging from 20 μηι to 2 mm and more particularly from. 50 μιη to 500 μπι. Needless to say, the thickness of the coating formed is adjusted with regard to the desired makeup effect.

Moreover, the coating thus formed is stable and long-lasting, in particular for at least 4 days and more particularly up to 7 days. It advantageously has good resistance to rubbing.

The process of the invention may advantageously be performed for hiding relief imperfections and more particularly wrinkles and in particular, as developed hereinbelow, the process of the invention makes it possible to obtain efficient and flexible filling of the skin wrinkles, for example facial wrinkles.

The process of the invention may also be used for concealing or attenuating skin defects, such as bags and/or shadows in the region around the eyes.

Also, as developed more particularly hereinbelow, it is possible via the process of the invention to create particularly advantageous volume effects or 3D relief on the skin, especially roughness effects similar to skin grain effects.

As developed in the text hereinbelow, the aerated coat of step (i) of the process of the invention may be formed according to various embodiments.

Preferably, it is formed in situ on the said skin surface via the application of a composition with delayed expansion.

According to another of its aspects, the present invention is thus directed towards such a cosmetic composition with delayed expansion comprising, in a physiologically acceptable medium:

- at least one photo-crosslinkable compound as defined previously; and

- at least one self-foaming compound.

The term "self-foaming compound" is intended to denote a compound that is capable of giving the composition containing it the form of a foam with an acceptable degree of aeration. The self-foaming compounds that may be used according to the inventio will be described more precisely in the text hereinbelow.

Alternatively, the said aerated coat may be formed, simultaneously with its application to the surface of the skin, with the aid of an aerated-composition dispenser, using a non- aerated base composition comprising the said photo-crosslinkable compound.

According to yet another of its aspects, the present invention thus relates to a product for forming an aerated cosmetic composition, comprising:

(a) a base composition comprising, in a physiologically acceptable medium, at least one photo-crosslinkable compound as defined previously; and

(b) an aerated-composition dispenser for dispensing the said base composition in the form of an aerated composition. According to yet another of its aspects, the present mvention relates to a cosmetic kit, in particular for making up and/or caring for the skin, comprising at least:

- a composition or a product as defined previously; and

- a lighting system capable of photo-crosslinking the said compound.

Other characteristics, variants and applications of the process, the composition, the product and the kit according to the invention will emerge more clearly on reading the description and the examples that follow, which are given as non-limiting illustrations.

Unless otherwise indicated, the term "containing/comprising one" should be understood as meaning "containing/comprising at least one".

STEP ffl: AERATED COAT

As mentioned previously, the process of the invention comprises the formation, on the said skin surface, of an aerated coat of a composition, referred to hereinbelow as (M), comprising at least one photo-crosslinkable compound.

PHOTO-CROSSLINKABLE COMPOUND

The photo-crosslinkable compounds under consideration according to the invention comprise at least one activated photo-dim erizable group bearing at least one activated double bond.

According to a particular embodiment, the said photo-crosslinkable compound(s) may be present in the composition (M) in a proportion of from 1% to 50% by weight and in particular from 3% to 20% by weight relative to the total weight of the said composition.

The mean number of activated double bonds per molecule of compound is preferably greater than 1, in particular greater than 2 and better still greater than 3.

For the purposes of the present invention, the term "photo-dimerizable group" means a chemical group that leads to photo-dimerization reactions under irradiation.

For the purposes of the present invention, the term "photo-dimerization" means a chemical reaction between two double bonds (of 2+2 type) or two pairs of double bonds (of 4+4 type), and more particularly between two double bonds (of 2+2 type).

Thus, the double bond under consideration accordin to the invention, when it is photo-stimulated or, in other words, subjected to a specific radiation, generally UV, proves to be capable of reacting with another double bond by cyclization.

As detailed hereinbelow, the interacting double bonds are preferably ethylenic functions, i.e. of the type CH₂=CH₂.

For the purposes of the invention, the double bond under consideration is said to be activated. This characterization means that the double bond is spontaneously photo- dimerizable in response to a photo-stimulus, without requiring the mandatory presence of a photoinitiator or of a chemical initiator.

Consequently, a composition according to the invention is advantageously free of photoinitiator and/or of chemical initiator.

The activation of the double bond intended to become dimerized is commonly induced by the presence close thereto, generally in the alpha position, of an electron- withdrawing group, for instance an aromatic nucleus such as a phenyl.

The case of a reaction between two double bonds may be represented schematically in the following manner:

These photo-dimerization reactions are defined in the book Advanced Organic Chemistry, J. March, 4th edition, Wiley Interscience, NY 1992, p. 855.

The materials bearing photo-dimerizable groups according to the invention have the advantage of being stable towards oxygen, moisture and heat, and of leading to reversible crosslinking.

In addition, the photo-dimerizable groups according to the invention are highly photosensitive. Consequently, irradiation even of low energy leads to rapid and efficient crosslinking of the material, which, in the case of a cosmetic application, induces irradiation of short duration and of low energy, which does not cause any degradation of the keratin materials .

The activated photo-dimerizable groups that may be used according to the invention are chosen from:

a) photo-dimerizable groups bearing a stylbazolium function of formula (la) or

(lb):

in which

- R represents a hydrogen atom or a C₁ -C4 alkyl or C1-C4 hydroxyalkyl group, preferably R represents a hydrogen atom, a methyl group, an ethyl group or a hydroxyefhyl group, and preferentially R is a methyl group;

- R' represents a hydrogen atom or a C1-C4 alkyl group and preferably R represents a hydrogen atom; and

- X^" denotes an ion chosen from chloride, bromide, iodide, perchlorate, tetrafiuoroborate, methyl sulfate, phosphate, sulfate, ¹ methanesulfonate and p- toluenesulfonate ions, preferably X^" is an ion chosen from chloride and methyl sulfate ions, and preferentially X^"is a methyl sulfate ion.

in which

denotes an alkylene radical (divalent) containing from 2 to 8 carbon atoms, and preferably R" denotes an alkyl ene radical (divalent) containing from 2 to 4 carbon atoms;

in which:

- Rj denotes a hydrogen atom or a C₁-C4 alkyl or C1-C4 hydroxyalkyl group; - A denotes a sulfur atom, an oxygen atom or a group NR' or C(R')2, R'; with R' representing a hydrogen atom or a C_rC₄ alkyl group, R' preferably representing a hydrogen atom; and

- X^" having the same meaning as that described for the preceding formula (la).

Such chemical groups bear activated double bonds, and as such the photo- dimerization of these double bonds is triggered spontaneously in the UVA range, without requiring a photoinitiator.

According to a preferred embodiment, the photo-dimerizable groups that may be used according to the invention bear a stylbazolium function of formula (la):

in which

- R represents a hydrogen atom or a C_rC₄ alkyl or Cs-Cj hydroxyalkyl group,

- R' represents a hydrogen atom or a Ci-C₄ alkyl group, and

- X^" denotes an ion chosen from chloride, bromide, iodide, perchlorate, tetrafluoroborate, methyl sulfate, phosphate, sulfate, methanesulfonate and p- toluenesulfonate ions.

The photo-crosslinkable compound is derived from the functionalization of a natural backbone, which is preferably polymeric, with at least one photo-dimerizable group.

This functionalization falls within the competence of a person skilled in the art. Advantageously, in the compositions of the invention, the compound comprising at least one photo-dimerizable group is a hydrocarbon-based polymer chosen from polyvinyl alcohol, partially or totally hydrolysed polyvinyl acetate and polysaccharides chosen from chondroitin sulfate, keratan, keratan sulfate, heparin, heparin sulfate, xanthan, carrageenan, chitosan, cellulose and derivatives thereof, alginate, starch, dextran, pullulan and galactomannan, and biologically acceptable salts thereof.

According to a particularly preferred embodiment of the invention, the photo- crosslinkable compound according to the invention may bear one or more functions that can. be cyclized in a 2/2 reaction., which are sensitive to light irradiation, in particular in the absence of photoinitiator and/or of chemical initiator.

Preferably, a photo-crosslinkable compound comprises at least one photo- dimerizable unit bearing a photo-dimerizable activated double bond, borne by a polymer of partially or totally hydrolysed polyvinyl acetate type, a polysaccharide or a polyvinyl alcohol.

As regards the compounds containing photo-dimerizable groups bearing a stylbazolium function, they are obtained by reacting the polymer under consideration with a chemical species comprising a group of formula (la) or (lb).

Preferably, the chemical species comprising a group (la) bears a reactive group W of aldehyde or acetal ty e.

In other words, this chemical species corresponds to the general formula W-A, with A denoting the group (la).

As chemical species that may be used for grafting groups of styrylpyridinium type, mention may be made especially of quaternary salts of 2-(4- formyl styryl )pyri di ni um, 4-( 4- form ylstyryl )p yrid i nium , 2-(3-formylstyryl)pyridinium, N- methyl-2-(4-fonnylstyryl)pyridimurn, N-methy3-3-(4-formylstyryl)pyridinium, N-methyl- 2-(3-formylstyryl)pyridinium, N~methyl-2-(2-formylstyryl)pyridinium. N-ethyl-2-(4- formylstyryl)pyridinium, N-(2-hydroxyeihyl)-2-(4-formylstyryl)pyridinium, N-(2- hydroxyethyl)-4-(4-formylstyryl)pyridinium, N-methyl-4-(4-formylstyryl)pyridinium or N- methyl -4-(3 -formyl styryl)pyridinium.

The quaternary pyridinium salts may be chloride, bromide, iodide, perchlorate, tetrafluoroborate, methosulfate, phosphate, sulfate, methanesulfonate or p-toluenesulfonate salts. Such chemical species are described in GB-A-2 030 575.

Examples of species that may be ^' mentioned include 4-(4- formylphenylethenyl)-l-methylpyridinium methosulfate, l-(3~ethoxycarbonylmethyl)-4- [2-(4-formylphenyl)ethenyl]pyridinium bromide and l-(methoxycarbonylpropyl)-4-[2-(4- formylphenyl)ethenyl]pyridimurn bromide. Such species are described in US 2007/0 1 12 094.

Use is preferably made of n-methyl-4-(4~fonnylstyiyl)pyridinium methyl sulfate (RN= 74401 -04-0), sold especially by the company Wako.

Advantageously, the chemical species of formula W-A react with a polymer of polyvinyl alcohol or polyvinyl acetal type as described in the documents mentioned previously.

For example, a polyvinyl alcohol -grafted polymer comprising units having the following structure is thus obtained:

Polyvinyl alcohol polymers grafted with a styrylpyridinium group are especially described in the publication ichimura K et al., Preparation and characteristics of photo-crosslinkable poly( vinyl alcohol), Journal of Polymer Science, polymer chemistry edition, Vol 20, 1419-1432 (1982).

The polymers may be obtained by reaction of polyvinyl alcohol or partially hydrolysed polyvinyl acetate with styrylpyridinium salts bearing a formyl or acetal group as described in GB-A-2 030 575, WO 96/29312, US 5 061 603, GB-A-2 076 826 and EP- A-092 901.

Cellulose polymers grafted with styrylpyridinium groups are especially described in US 2007/0 1 12 094.

Preferably, the chemical species bearing a group (la) bears a reactive group which is a chlorine atom.

in this variant, the chemical species corresponds to a general formula Cl-A', with A' denoting the group (la).

As chemical species of the type Cl-A', use is preferably made of that of formula:

corresponding to the chloro compound (1) described in the preparation examples hereinbelow.

Advantageously, the photo-crosslinkable compound comprising the groups (lb) is advantageously obtained by reaction of the species Cl-A¹ with the polysaccharide chosen from those defined previously, in the presence of water.

For their part, the compounds containing photo-dimerizable groups bearing a styrylazolium function are obtained by reaction of the polymer with a chemical species comprising a group of formula (II).

Preferably, the chemical species comprising a group (II) bears a reactive group

W of aldehyde or acetal type.

In other words, the chemical species corresponds to a general formula W-B, with B denoting the group (II).

As chemical species that may be used for grafting groups of styrylazoli um type, mention may be made of those described in EP-A-313 220.

Advantageously, these chemical species of formula W-B react with a polymer of polyvinyl alcohol or polyvinyl acetal type as described in the documents mentioned previously.

A polyvinyl alcohol-grafted polymer comprising units having the following structure is thus obtained:

Polyvinyl alcohol polymers grafted with a styrylazolium group are especially described in EP-A-313 220. In this document, these polymers may be obtained by reaction of polyvinyl alcohol or partially hydrolysed polyvinyl acetate with styrylazolium salts bearing an aldehyde or acetal group.

Preferably, the polymer bearing photo-dimerizable group(s) is in the form of particles, in particular dispersed particles.

Thus, in the latter case, the polymer particles are very preferentially polyvinyl alcohol particles.

Thus, according to one embodiment variant, the photo-crosslinkable compound is a polyvinyl alcohol (PVA) partly functionalized with one or more hydroxyl functions and one or more functions of formula (III):

The degree of polymerization of the polyvinyl alcohol may be between 100 and

5000.

Advantageously, the polymer has a degree of substitution, as a percentage of functions of formula (la), (lb) or (II) as defined above, which may be between 0.1 and 25.

The following scheme represents a variant in which the polymer is PVA-SbQ (polymer of polyvinyl alcohol PVA type bearing a few hydrolysed functions and a few functions grafted with stylbazolium species), which is capable of crossiinking under the effect of light, as illustrated below:

These materials are particularly appreciated since they do not require photoinitiator and react towards visible light or towards radiation which may comprise both UV light and visible light, in particular a low dose of UV.

By way of example, mention may be made of PVA-SbQ (poly( vinyl alcohol) with N-methylstyrylpyridinium side groups in the form of the methyl sulfate salt), sold under the reference MQ2012 by the company Murakami, especially in the form of a dispersion at 13.3% by weight in water, for example of CAS No: 107845-59-0.

According to another embodiment variant, the photo-crosslinkable compound is featured by a polysaccharide that is functionalized with photo-dim erizable groups.

It may especially be a polysaccharide that may be chosen especially from chondroitin sulfate, keratan, keratan sulfate, heparin, heparin sulfate, xanthan, carrageenan, chitosan, cellulose and derivatives thereof, alginate, starch, dextran, puliulan and galactomannan, and biologically acceptable salts thereof.

The degree of functionalization is obviously adjusted so as to be able to impart the required degree of crosslinking during step (ii) of the process of the invention.

According to the invention, the degree of functionalization with photo- dimerizable units is at least 0.1%, or even at least 0.5%, or even at least 2%.

As stated previously, in a composition according to the invention, the photo- dimerizable groups are preferably borne by a polymer of polyvinyl acetate type, a polyvinyl alcohol or a polysaccharide.

Preferably, in a composition according to the invention, the photo-dimerizable groups are borne by a polyvinyl alcohol.

The photo-crosslinkable compound may be conveyed in a physiologically acceptable medium and in particular an aqueous medium or even pure water.

The photo-crosslinkable compound may have a number-average molecular weight ranging from 2000 to 100 000 and preferably ranging from 2000 to 20 000.

According to another particular embodiment, the photo-crosslinkable compound may be chosen from polyurethane and/or polyurea polymers or oligomers bearing (meth)acrylate groups, in particular polyurethane (meth)acrylate oligomers.

Such polyurethanes/polyureas bearing acrylate groups are sold, for example, under the name Ebecryl® by the company Cytec (Ebecryl© 210: molar mass 1500, 2 acrylate functions per molecule, Ebecryl® 230: molar mass 5000, 2 acrylate functions per molecule, Ebecryl® 270: molar mass 1500, 2 acrylate functions per molecule, Ebecryl® 8402: molar mass 1000, 2 acrylate functions per molecule, Ebecryl® 8804: molar mass 1300, 2 acrylate functions per molecule, Ebecryl® 220: molar mass 1000, 6 acrylate functions per molecule, Ebecryl® 1290: molar mass 1000).

Mention may also be made of the water-soluble aliphatic acrylate polyurethanes sold under the names Ucecoat® 6558 and Ucecoat® 6569, and the acrylate polyurethanes in aqueous dispersion sold under the trade names Ucecoat® 7571 , Ucecoat® 7578, Ucecoat® 7655, Ucecoat® 7674, Ucecoat® 7689 and Ucecoat® 7699 by the company Cytec.

These compounds are capable of crosslinkmg when they are subjected to radiation comprising at least UV light.

An example that may be mentioned is diurethane methacrylate (INCI: Di- HEMA trimethylhexyl dicarbamate).

The composition may contain a single photo-crosslinkable polymer bearing functions of identical or different nature.

It is also possible to use a mixture of photo-crosslinkable polymers bearing different functions.

Consequently, the reactions may be performed between two photo-dimerizable groups of identical or different chemical nature.

The activated double bonds may react with another double bond of the same chemical nature or react with another double bond of different chemical nature.

Preferably, the photo-crosslinkable compound under consideration according to the invention is chosen from polymers that are capable of photo- crosslinkmg via a 2+2 cycloaddition reaction, in particular polymers bearing stylbazolium functions. Characteristics of the aerated coat

According to a particular embodiment, the said aerated coat formed in step (i) has a degree of aeration of greater than or equal to 10% and preferably less than 1000%.

The degree of aeration may range, for example, from 10% to 500% and preferably from 20% to 200%.

The degree of aeration corresponds to the amount of gas incorporated into the composition.

The degree of aeration is measured according to the following protocol: prior to the measurement, a quantity Q of composition to be characterized is placed in a transparent container bearing graduations indicating the volume, before aeration, and the volume Vb_ef_ore aeration (in cm ) is measured (in practice, the quantity is such that Vb_ef_OTe aeration is of the order of 10 cm^J) at a room temperature of 23 °C and at atmospheric pressure. In practice also, provision is made, in order to measure the volume, to tap the quantity Q in the bottom of the container, gently enough so as not to cause appreciable expansion of the product. The quantity Q of composition is then left alone for about 10 minutes in order for it to aerate by itself, naturally. The new volume V_foam of the composition in foam form is then measured. If need be, the top of the foam is levelled off somewhat in order to give it a flat surface, in this way, it is easier to evaluate the volume.

As detailed hereinbelow, the aeration may result from expansion of the composition with delayed expansion or may be created via an aerated-composition distributor.

The degree of aeration is then calculated with the aid of the following formula: degree Of aeration = [(V_foaro- V _{bd re} aeration)/ V before aeration] ^x 100

FORMATION OF THE AERATED COAT

According to a first variant of the process of the invention, the composition in foam form is created in situ on the said skin surface, after application of a composition with delayed expansion (E).

A composition with delayed expansion is a system comprising a "self- foaming" agent which is capable of enabling expansion of the said composition to give it the form of a foam, generally by release or formation of a volatile agent in the composition after it has been applied to the said skin surface.

Thus, according to a particular embodiment, the said aerated coat is formed via at least the steps consisting in:

(a) applying to the said skin surface at least one coat of a composition with delayed expansion, denoted (E), comprising at least one photo-crosslinkable compound as defined previously and at least one self-foaming compound, and

(b) exposing all or part of the said coat from step (a) to conditions that are favourable for expanding the said composition.

In this embodiment, the second crosslinking step is delayed until the transformation of the coat with delayed expansion into an aerated coat.

The term "self-foaming agent" means a compound that is capable of imparting to a composition the form of a foam with an acceptable degree of aeration.

This variant is particularly advantageous in so far as it does not require, unlike compositions conditioned in foam form, the spreading of a foam in order to form the aerated coat, which may often prove to be difficult to form a uniform coating.

According to another of its aspects, the present invention relates to a cosmetic composition with delayed expansion comprising, in a physiologically acceptable medium:

- at least one photo-crosslinkable compound as defined previously; and

- at least one self- foaming compound.

The composition with delayed expansion used according to the invention, before aeration, may be more or less fluid and may have the appearance of a coloured or colourless cream, an ointment, a milk, a lotion, a serum, a paste or a powder. It may also be in solid form, in particular in stick or dish form.

The composition with delayed expansion may be in anhydrous form or in the form of an emulsion or a gel.

Needless to say, it falls to a person skilled in the art to adapt the form of the composition with regard especially to the nature of the self- foaming compound used.

The composition with delayed expansion may be applied to the skin via any applicator usually used for the application of a cosmetic composition.

The composition with delayed expansion may be dispensed, for example, on the skin in the form of a cream, in particular formed from an emulsion.

The said composition may be conditioned in a standard aerosol device, with a separation such as a piston or a flexible bag to separate the self-foaming compound from the propellant required for expelling the composition. It may also be a flexible tube, a pump bottle or a bottle with a deformable wall.

These devices are well known to those skilled in the art. Examples 1 and 2 describe an example of a dispenser for compositions with delayed expansion in accordance with the invention.

Needless to say, it falls within the knowledge of a person skilled in the art to adapt the characteristics of the dispenser with regard especially to the nature of the self- foaming compound used.

The dispenser may be equipped, for example, with a dispensing control device specially adapted for the dispensing of a self-foaming product, as described, for example, in patent application EP 0 547 925.

The said self-foaming compound(s) may be chosen from the agents known to those skilled in the art, provided that they are capable of giving the composition the form of a foam with an acceptable degree of aeration, and of doing so under conditions that are compatible with application to the skin.

These self- foaming compounds may be chosen, for example, from: - slow-expanding systems

The self-foaming agent may be chosen, for example, from volatile hydrocarbons and volatile halogenated hydrocarbons with a boiling point low enough to enable them to evaporate and to foam the composition after application to the skin, and a boiling point that is high enough to prevent premature foaming.

The boiling point of the self- foaming agent preferably ranges from -20 to 40°C.

The self-foaming agent is preferably chosen from linear or branched C-4-C₆ aliphatic hydrocarbons.

Preferably, it is chosen from n-pentane, isopentane, . neopentane, n-butane, isobutane and isohexane, and mixtures thereof; and more preferentially isopentane.

- gas-releasing systems

These may be systems that release C0₂ by acidification of a carbonate, as described, for example, in patent application EP 1 133 983; or aqueous hydrogen peroxide solution that has been made unstable by basification or addition of a compound that promotes the dismutation of water.

- heat-foaming or heat-expandable systems

These may be "heat-expandable" particles, which are capable of expanding under the action of a temperature of gi'eater than or equal to 45 °C. They are preferably thermoplastic particles, which are capable of deforming under the action of heat and of conserving their new shape, including after cooling, especially to room temperature.

Examples that may be mentioned are the particles sold under the name Expancel® by the company Akzo Nobel.

According to a particular embodiment, the said self-foaming compound is chosen from slow-expanding systems, in particular as described previously.

According to a particularly preferred embodiment, it is isopentane, or alternatively an isopentane/isobutane mixture especially in a weight ratio ranging from 1/1 to 3/1 .

The said composition advantageously has a degree of expansion ranging from 10% to 5000%.

The term "degree of expansion" means the ratio between the volume occupied by the composition measured 15 minutes after its application, divided by the volume occupied by the composition measured immediately after its application.

A person skilled in the art is capable of using the said self-foaming agent(s) in an adequate amount for obtaining the desired degree of expansion.

hi particular, the said self-foaming agent(s) may be present in the composition with delayed expansion in a content ranging from 0.1 % to 40% by weight relative to the total weight of the said composition.

A person skilled in the art. is capable of using the conditions of exposure of the said coat formed in step (a) to obtain the desired expansion of the said composition.

Depending on the nature of the self-foaming agent used, the aerated composition may be obtained, for example, after exposure to atmospheric pressure and/or to a shear and/or to a temperature above room temperature.

In particular, in the context of using a self- foaming compound of volatile hydrocarbon type as described previously, step (b) may consist simply in leaving the said coat formed in step (a) to expand in the ambient atmosphere, especially for a time ranging from 10 seconds to 5 minutes.

According to a particular embodiment, the process of the invention also comprises the application, prior to, simultaneously with or subsequent to the application in step (a) of the said composition with delayed expansion (E) and prior to step (b), of at least one conventional cosmetic composition, for example a conventional foundation.

Preferably, the said compositions are mixed on the said skin surface itself, so as to create partial or total homogenization.

Such a variant makes it possible to obtain a volume effect via the expansion of the composition, while at the same time maintaining good smoothing.

According to a particularly preferred embodiment, in the context of performing the process of the invention for filling wrinkles, step (a) of applying the composition with delayed expansion to the wrinkles may be followed by a levelling step prior to the expansion step (b), for example using a spatula or a pad of cotton wool. According to yet another particular embodiment, a mould may be applied, simultaneously with the expansion (b) of the said composition, the mould being such that it makes it possible to define a specific volume above the said skin surface.

The mould may be made, for example, of plastic, for instance of polyethylene, polystyrene or of fluorinated material, for example of polytetrafluoroethylene (PTFE).

The application of a mould advantageously makes it possible to control the expansion of the composition, in particular the volume and shape of the aerated coat that will be fonned on the skin surface, and thus makes it possible to obtain a very smooth coating with very good homogeneity.

According to a second variant of the process of the invention, the foam appearance is generated at the time of dispensing the composition onto the skin.

More particularly, the said aerated coat of step (i) of the process of the invention may be formed, simultaneously with its application to the said skin surface, from a non-aerated base composition comprising the said photo-crossl kable compound, and using an aerated-composition dispenser that is capable of dispensing the base composition in the form of an aerated composition.

As mentioned previously, according to one of its aspects, the invention relates to a product for forming an aerated cosmetic composition, comprising:

(a) a non-aerated base composition comprising, in a physiologically acceptable medium, at least one photo-crosslinkable compound as defined previously; and

(b) an aerated-composition dispenser for dispensing the said base composition in the form of an aerated composition.

The aerated composition may be formed from the base composition and air or an inert gas.

The base composition which serves to obtain the aerated composition has a similar composition to the aerated composition except for its higher density in so far as it is free of air or inert gas.

These aerated-composition dispensers are well known in the cosmetics field. Such a dispenser comprises at least:

- a reservoir containing the base composition, and

- a dispensing head for dispensing the aerated composition.

This dispenser may be an aerosol, comprising, besides the base composition, a propellant gas.

The propellant gas that may be used may be chosen from carbon dioxide, nitrogen, nitrous oxide, volatile hydrocarbons such as butane, isobutane, propane, ethane, pentane, isododecane or isohexadecane, and mixtures thereof.

Alternatively, the dispenser may contain no propellant gas. In this case, the base composition may be in an aerated-composition dispenser comprising a dispensing head for dispensing the aerated composition, a pump and a dip tube for transferring the composition from the container into the head to dispense the aerated composition. The aerated composition is formed by forcing the base composition to pass through a material comprising a porous substance such as a sintered material, a plastic or metal filtering grille, or similar structures.

PHYSIOLOGICALLY ACCEPTABLE MEDIUM

The composition under consideration according to the invention should be cosmetically or dermatologically acceptable, i.e. it should contain a non-toxic physiologically acceptable medium that can be applied to human skin. For the purposes of the invention, the term "cosmetically acceptable" means a composition of pleasant appearance, odour and feel.

^•The composition used according to the invention, before aeration, may be in any galenical form normally used in the cosmetics field, and may especially be in the form of an oily solution, which is preferably thick or thickened, an emulsion obtained by dispersing a fatty phase in an aqueous phase (O/W) or conversely (W/O), a triple emulsion (W/O/W or 0/W/O), an aqueous gel, which is preferably thick, a vesicular dispersion of ionic type (liposomes or oieosomes) and/or of nonionic type (niosomes) and/or a dispersion of nanocapsules or nanospheres, which is preferably thick.

In the case of an emulsion, the proportion of the fatty phase in the composition under consideration may range, for example, from 5% to 80% by weight and especially from 5% to 50% by weight relative to the total weight of the composition.

Aqueous phase

The composition may comprise at least one aqueous phase.

The aqueous phase may consist essentially of water. However, it may also comprise a mixture of water and of water-miscible organic solvent (mi stability in water of greater than 50% by weight at 25°C), such as lower monoalcohols containing from 1 to 5 carbon atoms such as ethanol and isopropanol, glycols containing from 2 to 8 carbon atoms such as propylene glycol, ethylene glycol, 1 ,3-butylene glycol and dipropylene glycol, C₃- C₄ ketones and C2-C4 aldehydes.

This aqueous phase (water and optionally the water-miscible organic solvent) may be present in the composition in a content ranging from 1% to 95% by weight, especially ranging from 3% to 80% by weight and in particular ranging from 5% to 60% by weight relative to the total weight of the composition,

Fatty phase

The composition may also comprise a fatty phase.

In particular, the fatty phase of the composition may comprise at least one oil chosen especially from:

- hydrocarbon-based oils of animal origin, such as perhydrosqual ene;

- hydrocarbon-based oils of plant origin, such as liquid triglycerides of fatty acids containing from 4 to 10 carbon atoms, and the liquid fraction of shea butter;

- synthetic esters and ethers, especially of fatty acids, for instance the oils of formulae R' COOR² and R OR² in which R¹ represents a fatty acid residue containing from 8 to 29 carbon atoms and R² represents a branched or unbranched hydrocarbon-based chain containing from 3 to 30 carbon atoms, for instance purcellin oil, isononyl isononanoate, isopropyl myristate, 2-ethylhexyl palmitate, 2-octyldodecyl stearate, 2 -octyldodecyl erucate or isostearyl isostearate; hydroxylated esters, for instance isostearyl lactate, octyl hydroxystearate, octyldodecyl hydroxystearate, diisostearyl malate, triisocetyl citrate, and fatty alcohol heptanoates, octanoates and decanoates; polyol esters, for instance propylene glycol dioctanoate, neopentyl glycol diheptanoate and diethylene glycol diisononanoate; and pentaerythritol esters, for instance pentaerythrityl tetraisostearate;

- linear or branched hydrocarbons of mineral or synthetic origin, such as volatile or non-volatile liquid paraffins and derivatives thereof, petroleum jelly, polydecenes, and hydrogenated polyisobutene such as parleam oil;

- fatty alcohols containing from 8 to 26 carbon atoms, for instance cetyl alcohol, stearyl alcohol and the mixture thereof (cetyl stearyl alcohol), octyl dodecanol, 2- butyloctanol, 2-h.exyldecanol, 2-undecylpentadecanol, oleyl alcohol or linoleyl alcohol;

- partially fluorinated hydrocarbon-based and/or sili cone-based oils, for instance those described in document JP-A.-2-295 912;

- silicone oils, for instance volatile or non-volatile polymethylsiloxanes (PDMS) containing a linear or cyclic silicone chain, which are liquid or pasty at room temperature, especially cyclopolydimethylsiloxanes (cyclomethicones) such as cyclohexasiloxane; polydimethylsiloxanes comprisin 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 trimethi cones, phenyl dimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyl dimethicones, diphenylmethyldiphenyl- trisiloxanes, 2-pheny ethyltrimethyl siloxysilicates and polymethylphenylsiloxanes; and

- mixtures thereof.

Wax, gum, pasty fatty substance

The composition may also comprise at least one wax, at least one gum and/or at least one pasty fatty substance, of silicone or non-silicone plant, animal, mineral or synthetic origin.

The waxes may be hydrocarbon-based, silicone and/or fluoro waxes, optionally comprising ester or hydroxy! functions. They are especially of natural origin.

The wax may represent from 0.01% to 10% by weight and especially from

0.1%) to 5% by weight relative to the total weight of the composition. According to a particular embodiment, the composition may be free of waxes.

Film- forming polymer

The composition may also comprise at least one film-forming polymer.

According to the present invention, the term "film-forming polymer" means a polymer that is capable of fomiing, by itself or in the presence of an auxiliary film-forming agent, a continuous film that adheres to the skin.

A film-forming polymer capable of forming a hydrophobic film, i.e. a polymer whose film has a solubility in water at 25°C of less than 1% by weight, is advantageously used.

The film-forming polymer may especially be at least one polymer chosen from the group comprising:

- water-soluble film-forming pol ym ers,

- aqueous dispersions of water-dispersible film-forming polymer particles, also known as "latices"; in this case, the composition of foundation type should comprise an aqueous phase,

- liposoluble film-forming polymers,

- lipodispersible film-forming polymers in the form of non-aqueous dispersions of polymer particles, preferably dispersions of polymeric particles, where appropriate surface-stabilized with at least one stabilizer, in one or more silicone and/or hydro carbon -based oils; these non-aqueous dispersions are also known as "NADs", and

- mixtures thereof.

Aqueous dispersions of film-forming polymer that may be used according to the invention include the acrylic dispersions sold under the names Neocryl XK-90^®, Neocryl A-1070^®, Neocryl A-1090^®, Neocryl BT-62^®, Neocryl A-1079^®, Neocryl A-523^® by the company Avecia-Neoresins. Dow Latex. 432^® by the company Dow Chemical, Daitosol 5000 AD^{^} by the company Daito Kasey Kogyo; or alternatively the aqueous polyurethane dispersions sold under the names Neorez R-981^®, Neorez R-974^® by the company Avecia-Neoresins, Avalure UR-405^®, Avalure UR-410^®, Avalure UR-425^®, Avalure UR-450^®, Sancure 875^®, Sancure 861^®, Sancure 878^®, Sancure 2060^® by the company Goodrich, Impranil 85^® by the company Bayer and Aquamere H-l 51 1^® by the company Hydromer.

Aqueous dispersions of film-forming polymer that may also be mentioned include the polymer dispersions resulting from the free-radical polymerization of one or more free-radical monomers inside and/or partially at the surface of pre-existing particles of at least one polymer chosen from the group consisting of polyurethanes, polyureas, polyesters, polyesteramides and/or alkyd polymers. These polymers are generally referred to as hybrid polymers.

As examples of water-soluble film-forming polymers that may be used according to the invention, mention may be made of proteins, for instance proteins of plant origin, anionic, cationic, amphoteric or nonionic chitin or chitosan polymers, cellulose polymers, acrylic polymers or copolymers, vinyl polymers and polymers of natural origin, which are optional!} modified, and mixtures thereof. Dispersions of film-forming polymer in the liquid fatty phase, in the presence of stabilizers, are described especially in documents EP-A-749 746, EP-A-923 928 and EP-A-930 060, the content of which is incorporated into the present patent application by way of reference.

Examples of liposoluble polymers which may be mentioned are copolymers of vinyl ester (the vinyl group being directly linked to the oxygen atom of the ester group and the vinyl ester containing a saturated, linear or branched hydrocarbon-based radical of 1 to 19 carbon atoms, linked to the carbonyl of the ester group) and of at least one other monomer which may be a vinyl ester (other than the vinyl ester already present), an α-olefin (containing from 8 to 28 carbon atoms), an alkyl vinyl ether (in which the alkyl group comprises from 2 to 18 carbon atoms) or an allylic or methallylic ester (containing a saturated, linear or branched hydrocarbon-based radical of 1 to 19 carbon atoms, linked to the carbonyl of the ester group).

The film-forming polymer may be present in the composition in a solids content ranging from 0.01% to 20% by weight and especially from 0.5% to 10% by weight relative to the total weight of the composition.

Other additives

The composition may also contain adjuvants that are common in cosmetics, such as emulsifiers, hydrophilic or lipophilic gelling agents, dyestuffs, hydrophilic or lipophilic active agents, preserving agents, antioxidants, solvents, fragrances, fillers, sebum-absorbing compounds, physical sunblocks and chemical sunscreens, odour absorbers and pH regulators.

The amounts of these various adjuvants are those conventionally used in the field under consideration, for example from 0.01% to 20% of the total weight of the composition. Depending on their nature, these adjuvants may be introduced into the fatty phase or into the aqueous phase.

in any case, these adjuvants, and the proportions thereof, will be chosen so as not to harm the desired properties according to the invention.

The composition may also comprise at least one surfactant.

These surfactants may be chosen from anionic and nonionic surfactants. Reference may be made to the document "Encyclopedia of Chemical Technology, Kirk- Othmer", volume 22, pp. 333-432, 3rd edition, 1979, Wiley, for the definition of the properties and functions of surfactants, in particular pp. 347-377 of this reference, for the anionic and no ionic surfactants.

Among the surfactants that may especially be used in the composition, mention may be made of;

- nonionic surfactants: fatty acids, fatty alcohols, polyethoxylated or poiyglycerolated fatty alcohols such as polyethoxylated stearyl or cetyistearyl alcohols, fatty acid esters of sucrose, alkylglucose esters, in particular polyoxyethylenated Cj-C₆ alkyl glucose fatty esters, and mixtures thereof,

- anionic surfactants: C16-C30 fatty acids neutralized with amines, aqueous ammonia or alkaline salts, and mixtures thereof.

As emulsifiers and co-emulsifiers that may be used, mention may be made, for example, of O/W emulsifiers such as fatty acid esters of polyethylene glycol, especially PEG-100 stearate, and fatty acid esters of glycerol, such as glyceryl stearate, and also W/O emulsifiers available, for example, under the trade names Abil WE09, Abil EM 90 and Abil EM97 from the company Degussa Goldschmidt, or the mixture of acetyl ethylene glycol stearate and of glyceryl tristearate sold by the company Guardian under the trade name Unitwix.

As hydrophilic gelling agents that may be used, mention may be made in particular of carboxy vinyl polymers (carbomer), acrylic copolymers such as acrylate/alkylacrylate copolymers, polyacrylamides, polysaccharides, natural gums and clays, and lipophilic gelling agents that may be mentioned include modified clays, for instance bentones, metal salts of fatty acids, hydrophobic silica and polyefhylenes.

As dyestuffs that may be used in particular in the composition, mention may be made of lipophilic dyes, hydrophilic dyes, pigments and nacres usually used in cosmetic or dermatological compositions, and mixtures thereof.

The liposoluble dyes are, for example, Sudan Red, DC Red 17, DC Green 6, β-carotene, soybean oil, Sudan Brown, DC Yellow 11, DC Violet 2, DC Orange 5 and quinoline yellow.

The pigments may be white or coloured, mineral and/or organic, and coated or uncoated. Among the mineral pigments that may be mentioned are titanium dioxide, optionally surface-treated, zirconium, oxide or cerium oxide, and also iron oxide or chromium oxide, manganese violet, ultramarine blue, chromium hydrate and feme blue. Among the organic pigments that may be mentioned are carbon black, pigments of D&C type and lakes based on cochineal carmine or on barium, strontium, calcium or aluminium.

The nacreous pigments may be chosen from white nacreous pigments such as mica coated with titanium or with bismuth oxychloride, coloured nacreous pigments such as titanium mica with iron oxides, titanium mica with, in particular, ferric blue or chromium oxide, titanium mica with an organic pigment of the abovementioned type, and nacreous pigments based on bismuth oxychloride.

The pigments may have undergone a surface treatment.

Among the pigments that may be used in the composition, mention may also be made of goniochrornatic pigments.

As fillers that may be used in the composition, mention may be made, besides the fillers described above in relation to the soft-focus composition, of pigments, starch crosslinked with octenylsuccinic anhydride sold by the company National Starch under the name Dry Flo Plus (28-1 160); polyamide particles and especially those sold under the name Orgasol by the company Atochem; microspheres based on acrylic copolymers, such as those made of ethylene glycol dimethacrylate/lauryl methacrylate copolymer sold by the company Dow Coming under the name Polytrap; expanded powders such as hollow microspheres and especially the microspheres sold under the name Expancel by the company Kemanord Plast or under the name Micropearl F 80 ED by the company Matsumoto; polymethacrylate-type powders (PMMA), silicone elastomers and silica powders of the Sunsphere type, silicone resin microbeads such as those sold under the name Tospearl by the company Toshiba Silicone; and mixtures thereof.

These fillers may be present in amounts ranging from 0.01% to 20% by weight and preferably from 1 % to 10% by weight relative to the total weight of the composition.

Fillers that are advantageous for use in the present invention are silica, mica and titanium dioxide.

Water-absorbing and/or sebum-absorbing compound

The composition used according to the invention may comprise at least one compound for absorbing water and/or an oil or a liquid fatty substance, for instance sebum.

Among the water-absorbing compounds, also known as hydro-absorbing compounds, mention may be made of superabsorbent crosslinked polyacrylates such as those sold by the company Norsolor under the name Aquakeep*, polyvinyl alcohol, carboxyvinyl polymers such as those sold by the company Goodrich under the name Carbopol^®, semi -synthetic cellulose derivatives such as carboxymethylcellulose, starches, biogums such as xanthan gum, guar gum, gum. arabic, gum tragacanth, biosaccharides, scleroglucans, casein, phytocolloids such as alginates, carrageenates, agar-agar, gelatin and cotton fibres.

As regards compounds having a capacity for absorbing and/or adsorbing an oil or a liquid fatty substance, for instance sebum (from the skin), mention may be made more particularly of "oil-uptake" fillers which may be of organic or mineral nature.

The filler may be chosen more particularly from silicas, silica silylates, polyamide powders (in particular Nylon-6), acrylic polymer powders, especially of polymethyl methacrylate, of polymethyl methacrylate/ethylene glycol dimethacrylate, of polyallyl methacrylate/ethylene glycol dimethacrylate or of ethylene glycol dimethacrylate/lauryl methacrylate copolymer; perlites; magnesium carbonate, and mixtures thereof.

Advantageously, the oil-absorbing powder may be a powder coated with a hydrophobic- treating agent.

The hydrophobic-treating agent may be chosen especially from fatty acids such as stearic acid; metal soaps such as aluminium dirayristate or the aluminium salt of hydrogenated tallow glutamate; amino acids; N-acylamino acids or salts thereof; lecithin, isopropyl triisostearyl titanate, and mineral waxes, and mixtures thereof.

Silica powders that may be mentioned include:

- porous silica microspheres, especially those sold under the names Sunsphere^® H53 and Sunsphere^® H33 (oil uptake equal to 3.70 ml/g) by the company Asahi Glass;

MSS-5Q0-3H by the company obo,

- polydimethylsiloxane-coated amorphous silica microspheres, especially those sold under the name SA Sunsphere^® H33 (oil uptake equal to 2.43 ml/g),

- silica silylate powders, especially those sold under the name Dow Coming VM-2270 Aerogel Fine Particles by the company Dow Corning (oil uptake equal to

10.40 ml/g),

- amorphous hollow silica particles, especially those sold under the name Silica Shells by the company obo (oil uptake equal to 5.50 ml/g),

- precipitated silica powders surface-treated with a mineral wax, such as precipitated silica treated with a polyethylene wax, and especially those sold under the name Acematt OR 412 by the company Evonik-Degussa (oil uptake equal to 3.98 ml/g).

Acrylic polymer powders that may be mentioned include:

- porous polymethyl methacrylate/ ethylene glycol dimethacrylate spheres sold under the name Microsponge 5640 by the company Cardinal Health Technologies (oil uptake equal to 1.55 ml/g),

- ethylene glycol dimethacrylate/lauryl methacrylate copolymer powders, especially those sold under the name Polytrap^® 6603 from the company Dow Corning (oil uptake equal to 6.56 ml/g).

Polyamide powders that may be mentioned include:

- nylon-6 powder, especially the product sold under the name Pomp610 by the company TUBE Industries (oil uptake equal to 2.02 ml/g).

A perlite powder that may especially be mentioned, is the product sold under the name Optimat 1430 OR by the company World Minerals (oil uptake equal to 2.4 ml/g).

A magnesium carbonate powder that may especially be mentioned is the product sold under the name Tipo Carbomagel by the company Buschle & Lepper (oil uptake equal to 2.14 ml/g) .

Active agents

As active agents that are common in cosmetics or dermatology, which may be used in the composition, mention may in particular be made of any active agent known for its activity on the ageing of the skin, for instance keratolytic or pro -desquamating agents, for example a-hydroxy acids, β-hydroxy acids, a-keto acids and β-keto acids, retinoids and esters thereof, retinal and retinoic acid and derivatives thereof. Mention may also be made of extracts of veinotonic plants, such as extracts of ruscus and/or of common horse chestnut; xanthine bases such as caffeine; vitamins, for instance vitamins A, B3, PP, B5, E, l and/or C and derivatives of these vitamins and especially esters thereof; free-radical scavengers; sunscreens; moisturizers, for instance polyols; ceramides; DHEA and derivatives thereof; coenzyme Q10; bleaching and depigmenting agents, for instance kojic acid, extracts of skullcap, mulberry, liquorice and/or camomile; para-aminophenol derivatives, arbutin and derivatives thereof, and mixtures thereof.

For use in the cosmetic treatment of greasy or combination skin, the composition may contain at least one active agent chosen from: vitamins B3 and B5; zinc salts, and in particular zinc oxide and zinc gluconate; salicylic acid and derivatives thereof such as 5-n-octanoylsalicylic acid; triclosan; capryloylglycine; an extract of clove; octopirox; hexamidine; and azeleic acid and derivatives thereof.

UVA and/or UVB screening agents chosen from organic screening agents and mineral screening agents optionally coated to make them hydrophobic may also be introduced into the composition.

Preferably, the composition used according to the invention comprises one or more additional compounds chosen from preserving agents, fragrances and absorbent compounds.

Needless to say, a person skilled in the art will take care to select the optional additional ingredients and/or the amount thereof such that the advantageous properties of the composition according to the invention are not, or are not substantially, adversely affected by the envisaged addition.

Preferably, the composition under consideration according to the invention is free of photoinitiator and/or of chemical initiator.

For the purposes of the present invention, the term "photoinitiator" means a compound which initiates the photo-dimerization reaction and releases a radical under irradiation, especially i the UV range.

As representatives of conventional photoinitiators, which are therefore not required according to the invention, mention may be made especially of thioxanthone, rose Bengal, phloxin, eosin, erythrosin, fluorescein, acriflavin, thionine, riboflavin, proflavin, chlorophylls, haematoporphyrin and methylene blue, and mixtures thereof, this list not being limiting.

STEP (u): CROSSLINKS G

According to a particular embodiment, step (ii) may be preceded by a step of smoothing the said coat of composition (M). This step may be performed, for example, using a mould to be applied onto the surface of the coat so as to give it a shape, or alternatively via a system for levelling or for removing the surplus foam, by scraping. Such a step advantageously makes it possible to improve the smooth and uniform appearance of the coating formed.

As mentioned previously, the process of the invention comprises at least one step (ii) of exposing all or part of the surface of the said aerated coat formed in step (i) to conditions suitable for crosslinking the said photo-crosslinkable compound.

It falls to a person skilled in the art to select the adequate exposure conditions, especially with regard to the nature of the photo-crosslinkable compound used in the composition.

Step (ii) may consist in illuminating the surface of the said coat with ambient light or with a source of artificial light.

The ambient or artificial light may emit radiation in the visible and/or UV range. Preferably, it emits at least a proportion of radiation in the UV range, for example a proportion of UV of at least 2% of the total light energy of the ambient light.

According to a particular embodiment, step (ii) comprises, or even consists in. illuminating the surface of the said coat with ambient light, in particular for a time of at least 1 minute.

The time of exposure to the ambient light may more particularly range from 10 seconds to 15 minutes and especially from 5 to 10 minutes.

According to another particular embodiment, step (ii) comprises, or even consists in, illuminating the surface of the said coat with a source of artificial light.

The time of exposure to the said artificial light may range from 10 seconds to 10 minutes and in particular from 30 seconds to 5 minutes.

The lighting system for providing artificial light may consist, for example, of lighting with a lamp, a torch, a laser or LEDs, for example in the form of an LED array.

The artificial light source may emit radiation in the visible range and/or radiation in the UV range.

The emitted light may or may not be monochromatic. The wavelength of the emitted light is preferably centred on 365 nm, in particular between 400 nm and 700 nm and better still between 365 nm and 550 nm.

The crosslinking may be initiated by illumination without the need for a photoinitiator.

Preferably, it will be a source of artificial light emitting energy of at least 0.2 mW/cm' and in particular from 0.5 to 20 mW/cm .

The crosslinking may take place with a reduced light intensity, and the lighting system may, for example, produce a light intensity of less than 50 mJ/cm² or even l O J/cm².

In particular, the light energy in the UV range is preferably less than 10 J/cm .

The twofold characteristic of the absence of photoinitiator and of relatively weak light intensity is particularly advantageous since it makes it possible to limit the harmful effects of aggressive initiators or of prolonged exposure to intense light, in particular in UV wavelengths.

A person skilled in the art will be capable of adapting the illumination characteristics, especially in terms of duration of exposure and of radiation wavelengths, wi th regard to the nature of the photo-crosslinkable compound used.

Thus, the photo-crosslinking of polyurefhanes bearing (meth)acrylate groups will require light emitting at least radiation in the UV range, whereas the photo- crosslinking of polymers of PVA-SbQ type may be performed with radiation in the visible range.

Other variants of the process of the invention, in the case of the use of a composition with delayed expansion, are described below.

Thus, according to a first embodiment variant, step (ii) may be performed, on all or part of the surface of the said coat, before the full expansion of the composition with delayed expansion (E).

It is thus possible to stop the expansion of the composition, by illumination of the surface of the coat with a source of artificial light, when the said coat has reached the desired thickness.

This embodiment variant may prove to be particularly advantageous in the case of performing the process of the invention for the treatment of wrinkles.

Specifically, by controlling the degree of expansion of the composition (E), it is possible to adjust the volume of expanded composition obtained to the volume required to fill the wrinkle, without creating a visible ridge on the surface of the skin.

Such a variant is represented schematically in Figure , in which:

- Figure la represents a coat (2) of composition with delayed expansion (E) applied to a wrinkle (1), before expansion; - Figure lb represents the aerated composition (2), in the case where it has reached its maximum degree of expansion; and

- Figure 1 c represents the coat of aerated composition (2), in the case where the ^• expansion of the composition has been stopped by illumination, when the thickness of the coat is sufficient to fill the wrinkle (1).

According to yet another variant, it is possible to perform heterogeneous illumination on the skin surface.

Thus, according to a particular embodiment, the process of the invention may comprise at least one step of illumination, as described previously, of one or more localized zones of the surface of the said coat of composition with delayed expansion (E), before the complete expansion of the said composition (E), or even immediately after its application (a) and prior to its expansion (b).

The said zones may be defined, for example, by means of a cache that is capable of permitting the illumination of only the said zone(s).

In particular, the process may comprise at least two illumination steps performed for different localized zones of the surface of the said coat of composition with delayed expansion (E), and when the said composition has reached different degrees of aeration.

It is thus possible to obtain on the said skin surface varied volume effects, by creating zones of more or less thick coating. For example, it is possible to create roughness effects, similar to the grain effects of natural skin. In particular, it is possible, for example, to produce small hollows about 0.4 mm in diameter and about 0.2 mm deep, and separated from each other by about 2 mm on average.

The process of the invention may also comprise one or more subsequent steps of superposition, onto the coating formed after step (ii), of one or more additional coats of conventional cosmetic compositions, such as standard foundation compositions.

It is thus possible, for example, to modify the colour of the coating obtained, to modify its gloss, or to improve the smoothness of the coating.

Preferably, the said additional composition(s) are applied to the surface of the coating obtained after the process of the invention, by spraying, for example with a device of aerosol type.

For example, a lacquer, for instance comprising a mixture of acrylic resin, ethanol and dimethyl ether, may be applied to the surface of the coatmg.

The present invention will be understood more clearly by means of the examples and the figure that follow.

These elements are given as illustrations of the invention and cannot be interpreted as limiting the scope thereof.

EXAMPLES

EXAMPLE 1

Expandable foundation with substantial expansion

Preparation of the composition

The formulation below is prepared in the absence of light, comprising the gradients given in Table 1 below.

TABLE 1

A rigid pressurizable bottle made of tin, of about 200 ml, from the company Impress Vendel is used (commercial reference 190-Impress Vendel). A valve from the company Coster (commercial reference C 30605) is attached to a bag. This bag is crimped onto the drum. The bag is then filled with 60 g of formulation.

3 g of isopentane are then introduced into the bag. Next, the whole is shaken. The space outside the bag is then pressurized with 5 g of a propane butane mixture. A push button is fixed onto the valve mounted on the bag.

Application to the skin

To use the product, the push button is pressed. When the product exits via the push button, it is spread gently on the skin, at a rate of 0.5 g for the area of a cheek.

Next, while refraining from retouching the composition applied to the skin, the coating is exposed to the ambient light.

Result

A thick coating about 0.12 mm thick is then obtained. The coating is not regular at the surface, thus imitating the natural irregularities of the skin.

The operation may optionally be terminated by spreading another foundation or a powder applied with a puff.

EXAMPLE 2

Expandable foundation with moderate expansion

Preparation of the composition

The formulation below is prepared in the absence of light, comprising the ingredients given in Table 2 below. TABLE 2

2 g of isopentane are then introduced into the bag. Next, the whole is shaken. The space outside the bag is then pressurized with 5 g of a propane/butane mixture. A push button is fixed onto the valve mounted on the bag.

Application to the skin

To use the product, the push button is pressed. When the product exits via the push button, it is spread gently on the skin, at a rate of 0.5 g for the area of a cheek. Next, while refraining from retouching the composition applied to the skin, the coating is exposed to the ambient light.

Result

A thick coating about 0.08 mm thick is then obtained.

Claims

1. Cosmetic process for making up and/or caring for a skin surface, comprising at least the steps consisting in:

(i) forming, on the said surface, an aerated coat of a composition comprising, in a physiologically acceptable medium, at least one photo-crosslinkable compound, the said compound comprising at least one activated photo-dimerizable group bearing at least one activated double bond; and

2. Process according to Claim 1 , in which the said photo-crosslinkable compound bears one or more functions that can be cyclized via a 2/2 reaction, which are

in which

- R represents a hydrogen atom or a Ci-C₄ alkyl or Cj-C₄ hydroxyalkyl group

- R' represents a hydrogen atom or a C1-C4 alkyl group, and

- X^" denotes an ion chosen from chloride, bromide, iodide, perchlorate, tetrafluoroborate, methyl sulfate, phosphate, sulfate, methanesulfonate and p- toluenesulfonate ions,

in which

- R" denotes a divalent alkylene radical containing from 2 to 8 carbon atoms; - R' represents a hydrogen atom or a C₁-C₄ alky! group; and

- X^" having the same meaning as that described for the preceding formula

(la), and/or

b) photo-dimerizable groups bearing a styi'ylazolium function of formula (II):

(II)

in which:

- R] denotes a hydrogen atom or a C1-C₄ alkyl or C₁-C4 hydro xyalkyl group;

- A denotes a sulfur atom, an oxygen atom or a group NR' or C(R')₂, R' ; with R^" representing a hydrogen atom or a C _:-C i alkyl group; and

- X^" having the same meaning as that described for the preceding formula

(la).

4. Process according to any one of the preceding claims, in which the photo- dimerizable group is a photo-dimerizable group bearing a stylbazoiium function of formula (la):

in which

- R represents a hydrogen atom or a C1-C4 alkyl or C1-C4 hydroxyalkyl group.

- R' represents a hydrogen atom or a Cj-C₄ alkyl group, and

5. Process according to any one of the preceding claims, in which the photo-crosslinkable compound is a polyvinyl alcohol partly functionalized with one or more hydroxyl functions and one or more functions of formula (III):

( i l l)

CH₃SO

6. Process according to Claim 1 , in which the said photo-crosslinkable compound is chosen from polyurethane and/or polyurea polymers or oligomers bearing (meth)acrylate groups, in particular polyurethane (meth)acrylate oligomers.

7. Process according to any one of the preceding claims, in which step (ii) comprises the illumination of the surface of the said coat with ambient light, the said ambient light in particular emitting at least a proportion of radiation in the UV range.

8. Process according to any one of the preceding claims, in which step (ii) comprises the illumination of the surface of the said coat with a source of artificial light, in particular emitting a proportion of radiation in the UV range.

9. Process according to any one of the preceding claims, in which the said coating obtained after step (ii) has a thickness of greater than or equal to 10 μπι, in particular ranging from 20 μηι to 2 mm. and more particularly from 50 μπι to 500 μτη.

10. Process according to any one of the preceding claims, in which the said aerated coat is formed via at least the steps consisting in:

(a) applying to the said surface of the skin at least one coat of a composition with delayed expansion comprising at least the said photo-crosslinkable compound and at least one self-foaming compound, and

11. Process according to the preceding claim, in which the said self-foaming compound is chosen from slow-expanding systems such as isopentane, gas-releasing systems, such as systems releasing CO2 by acidification of a carbonate or of aqueous hydrogen peroxide solution made unstable by basification or addition of a compound which promotes the dismutation of water, and heat-foaming or heat-expandable systems.

12. Process according to Claim 10 or 1 1 , in which the said self-foaming compound is a slow-expanding system chosen from volatile hydrocarbons and volatile halogenated hydrocarbons with a boiling point ranging from -20 to 40°C, in particular from linear or branched C4-C6 aliphatic hydrocarbons.

13. Process according to any one of Claims 10 to 12, in which the said self- foaming compound is chosen from n-pentane, isopentane, neopentane, n-butane, isobutane and isohexane, and mixtures thereof; and preferably isopentane.

14. Process according to Claim 12 or 13, in which step (b) is performed in the ambient atmosphere, in particular for a time ranging from 10 seconds to 5 minutes.

15. Process according to any one of Claims 10 to 14, in which step (ii) is performed, on all or part of the surface of the said coat, before the complete expansion of the composition with delayed expansion.

16. Process according to any one of Claims 1 to 9, in which the said aerated coat is formed, simultaneously with its applicatio to the said skin surface, from a non- aerated base composition comprising the said photo- crosslinkable compound, and using an aerated-composition dispenser that is capable of dispensing the base composition in the form of an aerated composition.