Patent Description:
It is known that light radiation with wavelengths of between <NUM> and <NUM> makes it possible to brown the human epidermis. However, rays with wavelengths more particularly between <NUM> and <NUM>, known as UVB rays, cause skin erythema and burns which can be detrimental to the development of a natural tan.

For these reasons, and also for aesthetic reasons, there is constant demand for means for controlling this natural tanning in order to control the colour of the skin; this UVB radiation should thus be screened out.

It is also known that UVA rays, with wavelengths of between <NUM> and <NUM>, and which cause tanning of the skin, are liable to induce adverse changes therein, in particular in the case of sensitive skin or skin that is continually exposed to solar radiation. UVA rays cause in particular a loss in the elasticity of the skin and the appearance of wrinkles, resulting in premature skin ageing.

It is therefore desirable also to screen out UVA radiation.

Many photoprotective compositions have been proposed to date for protecting against the effects induced by UVA and/or UVB radiation. These compositions generally contain organic or mineral screening agents, more particularly mixtures of organic liposoluble screening agents and/or of water-soluble screening agents, combined with metal oxide pigments such as titanium dioxide or zinc oxide. These inorganic particles make it possible to increase the sun protection, which reduces the amount of organic screening agents and can thus improve the cosmeticity of the formulations.

While mineral screening agents such as titanium dioxide or zinc oxide are widely used in cosmetics for their UV-Absorbing properties, they cause, however, whitening when they are applied to the skin, which is not attractive.

It is known practice from patent application <CIT> to use monodisperse particles that are capable of forming a network and that have optical properties of filtering in the UVB, UVA and infra-red ranges. In said patent application, the particles must be organized on the skin.

Compositions containing photonic particles and clays are disclosed in patent application <CIT>.

This type of material has especially been used in two-phase cosmetic compositions, comprising a continuous aqueous phase in which are dispersed solid photonic particles.

This type of composition affords access to a high SPF, but a drawback thereof is the sedimentation and aggregation of the photonic particles, which form a block that is very difficult to redisperse once formed. This drawback harms the performance of the composition in the long term since the amount of photonic particles really dispersed has a tendency to decrease over time. The materials (or photonic particles), and in particular opals, are colloidal crystals, i.e. three-dimensional periodic structures based on the assembly of colloidal particles or of empty spaces. These assemblies enable physical attenuation of UV rays. This attenuation is adjusted by the periodicity of the lattice in the material and its refractive index, in particular the difference in index between the material and the medium.

It is advantageous to convey photonic particles in an aqueous phase in order to ensure a maximum difference in index between the material and the medium. Photonic materials are difficult to formulate as emulsions since they have a tendency to migrate into the fatty phase or to position themselves at the interface of the emulsion droplets. Their efficacy is then reduced. High-SPF compositions in the form of emulsions in which the photoprotective properties of the photonic materials are expressed without compromising the cosmetic properties such as the greasy, tacky and/or white finish are sought.

The inventors have found, surprisingly, that the addition of a particular acrylic polymer makes it possible to obtain stable, high-SPF emulsions with improved cosmetic properties. In particular, after application to the skin, there is no whitening effect, the skin is soft and is neither greasy nor tacky.

According to a first of its aspects, the invention relates to a composition, especially a cosmetic composition, in particular a photoprotective composition, comprising at least:.

According to another of its aspects, the invention relates to a cosmetic and especially photoprotective composition comprising, in a physiologically acceptable medium, a composition according to the invention as defined above.

The photoprotective cosmetic composition according to the invention has, for example, an SPF of at least <NUM>, or even of at least <NUM>, better still <NUM>, better still at least <NUM>, <NUM> or <NUM>. The SPF (sunscreen protection factor) is defined in the article <NPL>).

The formulation of the photoprotective cosmetic composition is chosen, for example, such that the composition has a transmission factor of less than or equal to <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or better still <NUM>%, for at least one wavelength in the range <NUM>-<NUM>, better still for the entirety of this range. The screening is proportionately better the lower the transmission factor in the range <NUM>-<NUM>.

In the text hereinbelow, and unless otherwise indicated, the limits of a range of values are included within that range, especially in the expressions "between" and "ranging from.

Moreover, the expressions "one or more" and "greater than or equal to" used in the present description are equivalent to the expressions "at least one" and "at least", respectively.

In the context of the invention, the photonic particles are also called opals.

Preferably, the photonic particles are present in the composition in the form of a dispersion.

The photonic particles may have a form factor of less than <NUM>, especially less than <NUM>. The form factor denotes, when the particle is oblong, the ratio of its greatest longitudinal dimension to its greatest transverse dimension. The photonic particles may be substantially spherical, then having a form factor equal to <NUM>.

A form factor of less than <NUM> may be advantageous in terms of surface coverage, relative to flat particles that can superimpose.

The mean size of the photonic particles is from <NUM> to <NUM>, preferably from <NUM> to <NUM>, advantageously from <NUM> to <NUM>, preferentially from <NUM> to <NUM> or even from <NUM> to <NUM>.

The term "mean size" denotes the statistical particle size dimension for half the population, referred to as D (<NUM>).

The photonic particles according to the invention may include filled or hollow nanoparticles ordered without a matrix or ordered or dispersed within any type of matrix, for example dispersed in a heat-, electro- or photo-crosslinkable matrix.

Photonic particles according to the invention may be, depending on the variants, qualified as direct, inverse or pseudo-inverse opals, as described below.

The photonic particles may be colourless. The photonic particles may be filled or hollow.

The photonic particles of "direct opal" type involve an arrangement of optionally composite, filled nanoparticles.

The photonic particles may include aggregated nanoparticles, preferably without a matrix.

A first process for manufacturing such particles, may, as described in the publication by<NPL>, include a step of obtaining a water-in-oil emulsion, the aqueous phase including monodisperse nanoparticles, followed by a step of obtaining photonic particles including a step of microwave irradiation of the emulsion obtained previously.

A second manufacturing process may, as described in the publication by<NPL>, include a step of aggregating SiO<NUM> or polystyrene nanoparticles under an electrospray.

Photonic particles of "direct opal" type may also be obtained via a process as described in the publication "<NPL>.

Photonic particles of "direct opal" type may also be obtained via an atomization process.

According to this process, the particles to be atomized are first dispersed in a water-based medium or in a homogeneous water/solvent mixture, said solvent being water-miscible, for instance an alcohol such as ethanol. The particle concentration may be from <NUM>% to <NUM>% by weight. The dispersion thus obtained is introduced into an atomizer, for instance Niro Minor Production; the injection rate (in the case of this machine) may be between <NUM> and <NUM><NUM>/h and preferably between <NUM> and <NUM>/h. The turbine speed is very high, preferably between <NUM><NUM> and <NUM><NUM> rpm. The atomization temperature may be between <NUM> and <NUM> and preferably between <NUM> and <NUM>.

The photonic particles of "direct opal" type may also include nanoparticles aggregated in a matrix, in contact with each other, or dispersed in a matrix.

Several processes, in addition to the processes described previously, may be suitable for manufacturing these photonic particles, especially the process of aggregation of SiO<NUM> particles in a silicon matrix, described in patent application <CIT>.

A second process may, as described in the publication by <NPL>, include a step of aggregation using an emulsion of PMMA nanoparticles.

The photonic particles of "direct opal" type may include nanoparticles dispersed in a photo-, electro- or heat-crosslinkable organic matrix.

The advantage of using a photo-crosslinkable, electro-crosslinkable or heat-crosslinkable organic matrix, especially a photo-crosslinkable or heat-crosslinkable matrix, lies in the possibility of modifying the distance between the nanoparticles contained in the matrix so as to vary the optical properties of the photonic particle. This distance may depend on the weight fraction of nanoparticles dispersed in the organic matrix, before photo-, electro- or heat-crosslinking, especially before photo- or heat-crosslinking. Said weight fraction is equal to the ratio of the weight of nanoparticles/weight of the matrix before heat-, electro- or photo-crosslinking.

According to a preferred embodiment of the invention, this weight fraction of nanoparticles is between <NUM>% and <NUM>% and better still between <NUM>% and <NUM>%.

This type of photonic particle may be obtained according to several emulsification processes, for example those described in the publication by <NPL> which uses silica particles dispersed in a UV-photopolymerizable ETPTA (ethoxylated trimethylolpropane triacrylate) photo-crosslinkable resin or in the publication "<NPL>.

In certain examples, the photonic particles are constituted of aggregated silica nanoparticles, without a matrix.

The photonic particles of "inverse opal" type include holes instead of nanoparticles.

They may be obtained from direct opals after destruction, for example by calcination or acidic hydrolysis, for example with <NUM>% hydrofluoric acid, of the nanoparticles, thus leaving empty spaces in place of all or some of the nanoparticles. The destruction step may possibly bring about a reduction in the size of the nanoparticle's imprint in the matrix, which may be up to <NUM>%.

The calcination (<NUM> to <NUM>) may be performed on direct opals based on organic nanoparticles and an inorganic matrix.

The acidic hydrolysis, for example with a hydrofluoric acid solution, may be performed on opals based on inorganic nanoparticles and an organic matrix.

In the case of inverse opals, the ratio of the volume occupied by the nanoparticles/volume occupied by the matrix (organic or precursor of the inorganic matrix) may be varied from <NUM>/<NUM> to <NUM>/<NUM>, which will have the effect of varying the surface porosity of the inverse opals. Such a variation is presented in the publication by <NPL>.

The inverse opals may be produced via the processes already described above for the direct opals including nanoparticles aggregated or dispersed in a matrix, followed by a step of destroying the nanoparticles, for example by calcination or acidic hydrolysis, for example as described in the following publications:.

By nature, inverse opals have no additional treatment of the porous materials whose optical properties will vary as a function of the medium, that may fill the holes in the opals.

In order to ensure the optical properties irrespective of the medium, photonic particles of inverse opal structure may be coated and rendered leaktight with respect to the medium in which they are immersed.

This coating may be done, for example, with polymers or waxes.

In a non-limiting manner, the materials for coating the particles may be chosen from:.

The mass ratio between the core of the photonic particle and the shell thus made may be between <NUM>/<NUM> and <NUM>/<NUM>, and preferably between <NUM>/<NUM> and <NUM>/<NUM>.

The photonic particles of "pseudo-inverse opal" type include hollow nanoparticles aggregated without a matrix or aggregated or dispersed within any type of matrix, for example dispersed in a heat-, electro- or photo-crosslinkable matrix.

Making direct opals from hollow nanoparticles, also called "pseudo-inverse opals", has the advantages of amplifying the optical effects by a higher index difference compared with direct opals that do not use hollow nanoparticles, and of offering zero porosity compared with uncoated inverse opals, whose optical properties are dependent on the medium in which they are dispersed.

The hollow nanoparticles may be as described below.

The photonic particles may be of Janus type, i.e. they may include at least one other diffracting arrangement of nanoparticles, or even at least two other diffracting arrangements, the arrangements each having intrinsic optical properties, especially different diffraction spectra.

In a first embodiment, one arrangement may include filled nanoparticles and another arrangement may include filled or hollow nanoparticles.

As a variant, one arrangement may include hollow nanoparticles and another arrangement may include hollow nanoparticles.

When the particles include several arrangements, each arrangement may cover, for example, a portion of the UV spectrum, so as to obtain broadened photoprotection.

The photonic particles including several diffracting arrangements may be obtained as taught in the publication by <NPL> or the publication <NPL>.

When the photonic particles are used at least in part for their colour properties, particularly for homogenization of the complexion, the arrangements of nanoparticles, when lit by white light, may produce different respective colours; the arrangements may especially produce red, green and/or blue, thereby allowing the production of a large number of tones and particularly white by additive synthesis of reflected light.

An arrangement has a red reflected colour, for example, when the reflectance in the visible spectrum is at least <NUM>% in the wavelength range extending from <NUM> to <NUM>, for an observation angle varying between <NUM> and <NUM>°. For green, the wavelength range under consideration extends from <NUM> to <NUM> and for blue from <NUM> to <NUM>. The arrangements may diffract light through different respective zones of the photonic particle, for example two opposite zones, for example two diametrically opposite hemispherical zones in the case of a spherical photonic particle.

One of the arrangements may have a diffraction spectrum with at least one first-order reflection peak in the wavelength range from <NUM> to <NUM> and another arrangement may have a diffraction spectrum with at least one first-order reflection peak in the wavelength range from <NUM> to <NUM> or <NUM> to <NUM>.

The composition according to the invention may include photonic particles of only one type or a mixture of at least two different types of photonic particles, for example having reflection peaks, especially of first order, centred on different wavelengths, located in the visible, UV or near-IR region.

The composition may, for example, include a mixture of one type of photonic particles including filled nanoparticles and another type of photonic particles including nanoparticles that may be filled or hollow.

The composition may, for example, include a mixture of one type of photonic particles including hollow nanoparticles and another type of photonic particles including nanoparticles that may be hollow.

The composition may, for example, include a mixture of one type of photonic particles including a heat-, electro- or photo-crosslinkable matrix and another type of photonic particles not including a heat-, electro- or photo-crosslinkable matrix.

The nanoparticles constituting the photonic particles may have a mean size of from <NUM> to <NUM> and preferably from <NUM> to <NUM>.

The nanoparticles may be of spherical shape.

The nanoparticles may be monodisperse to <NUM>% or better. The term "monodisperse to x%" refers according to the invention to particles whose mean size has a coefficient of variation CV of less than or equal to x%.

The coefficient of variation CV is defined by the relationship: <MAT>.

The mean size D and the standard deviation s may be measured on <NUM> particles by analysis of an image obtained using a scanning electron microscope, for example the machine referenced S-<NUM><NUM> from the company Hitachi. Image analysis software may be used to facilitate this measurement, for example the Winroof® software sold by the company Mitani Corporation. Preferably, the coefficient of variation of the monodisperse nanoparticles is less than or equal to <NUM>%, better still less than or equal to <NUM>%, or even better still less than or equal to <NUM>%, for example being substantially of the order of <NUM>% or less.

The nanoparticles may be filled or hollow, and organic or inorganic.

The nanoparticles may be monomaterial or composite.

When the monodisperse nanoparticles are composite, they may, for example, include a core and a shell made of different materials, for example organic and/or mineral materials.

The nanoparticles may include an inorganic compound, or even may be entirely mineral.

When the nanoparticles are inorganic, they may include, for example, at least one oxide, especially a metal oxide, for example chosen from silica, silicon, iron, titanium, aluminium, chromium, zinc, copper, zirconium and cerium oxides, and mixtures thereof. The nanoparticles may also include a metal, especially titanium, silver, gold, aluminium, zinc, iron or copper and mixtures and alloys thereof.

According to one embodiment, the nanoparticles comprise silica, at least one metal oxide, especially as described above, or a mixture of silica and of at least one metal oxide, especially as described above.

The nanoparticles may include an organic compound, or even may be entirely organic.

Among the materials that may be suitable for making organic nanoparticles, mention may be made of polymers, especially with carbon-based or silicon-based chains, for example polystyrene (PS), polymethyl methacrylate (PMMA), polyacrylamide (PAM), silicone polymers, NADs ("non-aqueous dispersions"), for instance rigid NADs that, as examples, are constituted of <NUM>% methyl methacrylate and <NUM>% ethylene glycol dimethacrylate crosslinked at <NUM>% in isododecane, particle diameter: <NUM> (polydispersity Q = <NUM>) or <NUM>% methyl methacrylate and <NUM>% allyl methacrylate, particle diameter: <NUM> or <NUM>% methyl dimethacrylate, particle diameter: <NUM> (polydispersity Q = <NUM>) or poly(methyl methacrylate/allyl methacrylate, polylactic acid (PLA), polylactic acid-glycolic acid (PLAGA), celluloses and derivatives thereof, polyurethane, polycaprolactone, latex form, chitin, composite chitin materials.

The glass transition temperature (Tg) of the organic nanoparticles may be greater than <NUM> and better still greater than <NUM>.

These nanoparticles include a core and a shell. The core may be organic or inorganic.

The nanoparticle shell may, for example, be made of PS and the particles may, for example, be aggregated within an organic matrix.

The nanoparticle shell may, for example, be made of PS and the particles may, for example, be dispersed within an organic heat-, electro- or photo-crosslinkable matrix.

The core of these hollow nanoparticles may be constituted by air or a gas other than air so as to benefit from a different refractive index, for example CO<NUM>, N<NUM>, butane or isobutane.

The presence of air or another gas inside the hollow nanoparticles may make it possible to obtain a great difference in refractive index between the nanoparticles and the surrounding medium, which is favourable in terms of intensity of the diffraction peak.

When the nanoparticles are hollow, the difference in refractive index at a diffracted wavelength between the core and the shell may be greater than or equal to <NUM>. Said diffracted wavelength may be between <NUM> and <NUM>, for example between <NUM> and <NUM>. When the nanoparticles are hollow, the ratio between a largest dimension of the core and a largest dimension of the nanoparticle may be between <NUM> and <NUM>. When the nanoparticles are hollow, the core volume represents between <NUM>% and <NUM>% and preferably between <NUM>% and <NUM>% of the total volume of the nanoparticle.

The thickness of the shell of the hollow nanoparticles, taken as equal to half the difference of the largest dimension of the nanoparticle and the largest dimension of the core of the nanoparticle, may be between <NUM> and <NUM>, for example between <NUM> and <NUM>.

Among the hollow nanoparticles that may be used, mention may be made of the <NUM> nanoparticles SX866(B) from the company JSR.

The core of the nanoparticles may optionally comprise a sunscreen or a mixture of sunscreens.

The photonic particles may include filled or hollow nanoparticles, which are aggregated or dispersed in any type of matrix, for example dispersed in a heat-, electro- or photo-crosslinkable matrix, or empty spaces dispersed in any type of matrix, for example dispersed in a heat-, electro- or photo-crosslinkable matrix, as mentioned above.

Among the organic matrices, mention may be made, in a non-limiting manner, of acrylic matrices: made of polymethyl methacrylate (PMMA) or polyacrylamide (PAM), matrices made of polyethylene terephthalate (PET), polystyrene (PS), polycaprolactone (PCL), polyvinyl acetate (PVA), polyvinylethyl acetate (PVEA), waxes with a melting point above <NUM>, for example above <NUM>, and with a hardness above <NUM> MPa and preferably above <NUM> MPa.

In particular, the matrix may be heat-crosslinkable, photo-crosslinkable or electro-crosslinkable.

The term "photo-crosslinkable matrix" should be understood as meaning a matrix whose crosslinking is induced and/or assisted by light radiation, especially UV.

The term "heat-crosslinkable matrix" should be understood as meaning a matrix whose crosslinking is induced and/or assisted by a supply of heat, for example bringing the matrix to a temperature above <NUM>.

The term "electro-crosslinkable matrix" should be understood as meaning a matrix whose crosslinking is induced and/or assisted by applying an electric field.

A matrix may be both heat-crosslinkable and photo-crosslinkable.

The photonic particles may include filled or hollow nanoparticles, dispersed in a heat-, electro- or photo-crosslinkable matrix or empty spaces dispersed in a heat-, electroor photo-crosslinkable matrix.

The heat-crosslinkable or photo-crosslinkable matrix may be organic.

Among the crosslinkable organic matrices, mention may be made in a non-limiting manner of:.

The crosslinking of the matrix may be chemical crosslinking, for example using succinimides as described in patent application <CIT>. For photo-crosslinkable matrices requiring a photoinitiator, the photoinitiator is chosen, for example, from the following list: DMPA (dimethoxy <NUM>-phenylacetophenone), <NUM>-benzyl-<NUM>-(dimethylamino)-<NUM>-[<NUM>-(<NUM>-morpholinophenyl]-<NUM>-butanone sold under the brand name Irgacure® <NUM> by Ciba®, <NUM>,<NUM>'-bis(diethylamino)benzophenone sold by Sigma-Aldrich®, <NUM>-hydroxy-<NUM>'-(<NUM>-hydroxyethoxy)-<NUM>-methylpropiophenone sold by Sigma-Aldrich®, <NUM>-benzyl-<NUM>-(dimethylamino)-<NUM>'-morpholinobutyrophenone sold by Sigma-Aldrich®, phenylbis(<NUM>,<NUM>,<NUM>-trimethylbenzoyl)phosphine oxide sold by Sigma-Aldrich®, isopropylthioxanthone sold by Sigma-Aldrich®, and camphorolactone.

The PEG diacrylates can crosslink, for example, with the aid of a photoinitiator such as camphorolactone.

Among inorganic matrices, examples that may be mentioned include metal oxide matrices, especially made of SiO<NUM>, TiO<NUM> or ZrO, or CaCO<NUM> or Si matrices.

According to preferred embodiments of the present invention, the opals are direct opals, the nanoparticles of which are constituted of filled particles made of inorganic material such as SiO<NUM>, TiO<NUM> or ZnO, or of composite material corresponding to a mixture thereof.

According to particularly preferred embodiments of the present invention, the opals are direct opals, the nanoparticles of which are constituted of filled SiO<NUM> particles.

By way of example, mention may be made of direct opals made from the aqueous dispersion of silica particles (Cosmo S-160NP from JGC). The opals are obtained by spray-drying according to the following preparation method.

The commercial dispersion is used as obtained, or is mixed with water to obtain a mass concentration of particles equal to <NUM>%.

The dispersion thus obtained is introduced into an atomizer (Niro Minor Production), the injection rate being set at <NUM>/h, the turbine speed being set at <NUM><NUM> rpm and the atomization temperature being set at <NUM>.

The mass content of photonic particles is preferably from <NUM>% to <NUM>% and preferentially from <NUM>% to <NUM>% by weight, relative to the total weight of the composition.

According to the invention, the polymer c) according to the invention comprises monomeric units of formulae (A) and (B):
<CHM>
in which:.

Preferably, R1 consists of alkyl radicals, preferably of C16-C22 alkyl radicals, and more preferentially stearyl (C18) radicals or of behenyl (C22) radicals.

Preferably, at least <NUM>% by weight of the groups R1 are stearyl or behenyl radicals, preferentially at least <NUM>% by weight and more preferentially at least <NUM>% by weight.

According to one preferred embodiment, all the groups R1 are behenyl radicals.

According another preferred embodiment, all the groups R1 are stearyl radicals.

Preferably, said weight ratio ranges from <NUM>:<NUM> to <NUM>:<NUM> and preferentially ranges from <NUM>:<NUM> to <NUM>:<NUM>.

Advantageously, the polymer units present in the polymer consist of the units (A) and (B) previously described.

The polymer has a number-average molecular weight Mn ranging from <NUM> to <NUM>/mol, preferably ranging from <NUM> to <NUM>/mol. The number-average molecular weight may be measured via the gel permeation chromatography method, for example according to the method described in the example hereinbelow.

Preferably, the polymer has a melting point ranging from <NUM> to <NUM> and preferentially ranging from <NUM> to <NUM>. The melting point is measured by differential scanning calorimetry (DSC), for example according to the method described in the example hereinbelow.

According to a first embodiment, when the polymer is such that at least <NUM>% by weight of the groups R1 are stearyl radicals, then the polymer preferably has a melting point ranging from <NUM> to <NUM>, and preferentially ranging from <NUM> to <NUM>.

According to a second embodiment, when the polymer is such that at least <NUM>% by weight of the groups R1 are behenyl radicals, then the polymer has a melting point ranging from <NUM> to <NUM>, and preferentially ranging from <NUM> to <NUM>.

The polymer used according to the invention may be prepared by polymerization of a monomer of formula
CH2=CH-COO-R1, R1 having the meaning previously described, and of <NUM>-hydroxyethyl acrylate.

The polymerization may be performed according to known methods, such as solution polymerization or emulsion polymerization.

The polymerization is, for example, described in <CIT>.

The polymer(s) c) according to the invention are preferably present in the composition in accordance with the invention in an amount ranging from <NUM>% to <NUM>% by weight, especially from <NUM>% to <NUM>% by weight and in particular from <NUM>% to <NUM>% by weight relative to the total weight of the composition.

The composition in accordance with the invention also comprises at least one UV-screening agent (agent for screening out UV radiation from sunlight). The UV-screening agent(s) may be chosen from hydrophilic, lipophilic or insoluble organic UV-screening agents and inorganic UV-screening agents, and mixtures thereof.

The term "UV-screening agent" means a substance that is capable of absorbing at least a portion of the UV radiation emitted by the sun, to protect the skin and/or the lips and/or the hair against the harmful effects of this radiation.

The UV-screening agent is a UV-screening agent normally used in cosmetics. It may be chosen from the positive list contained in Annex VI of (EC) Regulation No. <NUM>/<NUM>, which specifies the list of UV-screening agents permitted in cosmetics.

According to a particular embodiment, the UV-screening agent(s) are present in the compositions according to the invention in an active material content ranging from <NUM>% to <NUM>% by weight and in particular from <NUM>% to <NUM>% by weight, relative to the total weight of the composition.

The water-soluble organic UV-screening agents are especially chosen from the following families:.

When the absorber is an organic UV-screening agent of sulfonic acid type, it is preferably combined with an amount of an organic base, such as an alkanolamine, so as to make it water-soluble.

The term "alkanolamine" means a C<NUM>-C<NUM> compound comprising at least one primary, secondary or tertiary amine function and at least one alcohol, generally primary alcohol, function.

As suitable alkanolamines, mention may be made of tromethanine and triethanolamine.

The organic screening agents, which are hydrophobic or insoluble in the usual solvents, may be chosen especially from various families of chemical compounds.

Mention may also be made of merocyanine-type screening agents such as those prepared according to the protocols described in <CIT>, in <NPL> <NPL>" and in <CIT> (column <NUM>, line <NUM> - column <NUM>, line <NUM> and the references cited in this regard).

The inorganic photoprotective agents are chosen from coated or uncoated metal oxide pigments (mean size of the primary particles: generally between <NUM> and <NUM>, preferably between <NUM> and <NUM>), for instance titanium oxide (amorphous or crystallized in rutile and/or anatase form), iron oxide, zinc oxide, zirconium oxide or cerium oxide pigments, which are all UV-photoprotective agents that are well known per se.

The coated pigments are pigments that have undergone one or more surface treatments of chemical, electronic, mechanochemical and/or mechanical nature with compounds as described, for example, in <NPL>, such as amino acids, beeswax, fatty acids, fatty alcohols, anionic surfactants, lecithins, sodium, potassium, zinc, iron or aluminium salts of fatty acids, metal alkoxides (of titanium or aluminium), polyethylene, silicones, proteins (collagen, elastin), alkanolamines, silicon oxides, metal oxides or sodium hexametaphosphate.

As is known, silicones are organosilicon polymers or oligomers comprising a linear or cyclic and branched or crosslinked structure, of variable molecular weight, obtained by polymerization and/or polycondensation of suitably functionalized silanes and essentially constituted of a repetition of main units in which the silicon atoms are connected to each other via oxygen atoms (siloxane bond), optionally substituted hydrocarbon-based radicals being connected directly to said silicon atoms via a carbon atom.

The term "silicones" also encompasses the silanes required for their preparation, in particular alkylsilanes.

The silicones used for coating the pigments that are suitable for the present invention are preferably chosen from the group containing alkylsilanes, polydialkylsiloxanes and polyalkylhydrosiloxanes. Even more preferentially, the silicones are chosen from the group containing octyltrimethylsilane, polydimethylsiloxanes and polymethylhydrosiloxanes.

Needless to say, before being treated with silicones, the metal oxide pigments may have been treated with other surface agents, in particular with cerium oxide, alumina, silica, aluminium compounds or silicon compounds, or mixtures thereof.

The coated pigments are more particularly titanium oxides that have been coated:.

The uncoated titanium oxide pigments are sold, for example, by the company Tayca under the trade names Microtitanium Dioxide MT <NUM> B or Microtitanium Dioxide MT <NUM> B, by the company Degussa under the name P <NUM>, by the company Wackher under the name Transparent titanium oxide PW, by the company Miyoshi Kasei under the name UFTR, by the company Tomen under the name ITS and by the company Tioxide under the name Tioveil AQ.

The uncoated zinc oxide pigments are, for example:.

The coated zinc oxide pigments are, for example:.

The uncoated cerium oxide pigments are sold under the name Colloidal Cerium Oxide by the company Rhône-Poulenc.

The uncoated iron oxide pigments are sold, for example, by the company Arnaud under the names Nanogard WCD <NUM> (FE 45B), Nanogard Iron FE <NUM> BL AQ, Nanogard FE 45R AQ and Nanogard WCD <NUM> (FE 45R) or by the company Mitsubishi under the name TY-<NUM>.

The coated iron oxide pigments are sold, for example, by the company Arnaud under the names Nanogard WCD <NUM> (FE 45B FN), Nanogard WCD <NUM> (FE 45B <NUM>), Nanogard FE <NUM> BL <NUM> and Nanogard FE <NUM> BL or by the company BASF under the name Transparent Iron Oxide.

Mention may also be made of mixtures of metal oxides, in particular of titanium dioxide and of cerium dioxide, including the equal-weight mixture of titanium dioxide and cerium dioxide coated with silica, sold by the company Ikeda under the name Sunveil A, and also the mixture of titanium dioxide and zinc dioxide coated with alumina, silica and silicone, such as the product M <NUM> sold by the company Kemira, or coated with alumina, silica and glycerol, such as the product M <NUM> sold by the company Kemira.

These metal oxide particles taken per se do not constitute photonic particles as defined according to the invention.

The inorganic screening agent(s) may be present in the compositions according to the invention in a concentration of between <NUM>% and <NUM>% and preferably between <NUM>% and <NUM>% by weight relative to the total weight of the composition.

Preferably, the mass ratio of the photonic particles to the polymer c) is from <NUM> to <NUM>, preferably from <NUM> to <NUM>.

The compositions according to the invention comprise at least one aqueous phase.

An aqueous phase contains water and optionally other water-soluble or water-miscible organic solvents.

An aqueous phase that is suitable for use in the invention may comprise, for example, a water chosen from a natural spring water, such as water from La Roche-Posay, water from Lucas, water from Vittel, water from Saint-Gervais or waters from Vichy, or a floral water.

The composition according to the invention may also contain at least one polar organic solvent, which is preferably physiologically acceptable.

The polar organic solvents are generally water-miscible.

As polar organic solvent, mention may be made of C<NUM>-C<NUM> monoalcohols such as ethanol or isopropanol; C<NUM>-C<NUM> polyols such as glycerol, <NUM>,<NUM>-propanediol, <NUM>,<NUM>-butanediol, <NUM>,<NUM>-pentanediol and <NUM>,<NUM>-hexanediol; C<NUM>-C<NUM> alkylene glycols such as ethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, pentylene glycol and hexylene glycol; and mixtures thereof.

The total content of C<NUM>-C<NUM> alcohols in the composition of the invention is preferably from <NUM>% to <NUM>% by weight and preferentially from <NUM>% to <NUM>% by weight of Ci-C<NUM> alcohols relative to the total weight of the composition.

The total content of C<NUM>-C<NUM> alkylene glycols in the composition of the invention is preferably from <NUM>% to <NUM>% by weight and preferentially from <NUM>% to <NUM>% by weight of C<NUM>-C<NUM> alkylene glycols relative to the total weight of the composition.

The composition according to the invention may include a volatile solvent.

For the purposes of the invention, the term "volatile solvent" means any liquid that is capable of evaporating on contact with keratin materials, at room temperature and atmospheric pressure.

The composition according to the invention may be chosen especially so that the composition contains at least <NUM>%, or even at least <NUM>%, or even at least <NUM>% of volatile solvent.

The composition according to the invention may include a fatty phase. The fatty phase may especially be volatile.

The composition may include an oil, for instance synthetic esters and ethers, linear or branched hydrocarbons of mineral or synthetic origin, fatty alcohols containing from <NUM> to <NUM> carbon atoms, partially hydrocarbon-based and/or silicone-based fluoro oils, silicone oils such as volatile or non-volatile polymethylsiloxanes (PDMS) bearing a linear or cyclic silicone chain, which are liquid or pasty at room temperature, and mixtures thereof, other examples being given hereinbelow.

A composition in accordance with the invention may thus comprise at least one volatile oil.

For the purposes of the present invention, 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 atmospheric pressure, in particular having a vapour pressure ranging from <NUM> Pa to <NUM><NUM> Pa (<NUM>-<NUM> to <NUM> mmHg), preferably ranging from <NUM> Pa to <NUM><NUM> Pa (<NUM> to <NUM> mmHg) and preferably ranging from <NUM> Pa to <NUM> Pa (<NUM> to <NUM> mmHg).

The volatile hydrocarbon-based oils may be chosen from hydrocarbon-based oils of animal or plant origin containing from <NUM> to <NUM> carbon atoms, and especially branched Cs-C<NUM> alkanes (also known as isoparaffins), for instance isododecane (also known as <NUM>,<NUM>,<NUM>,<NUM>,<NUM>-pentamethylheptane), isodecane, isohexadecane and, for example, the oils sold under the trade names Isopar® or Permethyl®.

Volatile oils that may also be used include volatile silicones, for instance volatile linear or cyclic silicone oils, especially those with a viscosity ≤ <NUM> centistokes (<NUM>×<NUM>-<NUM> m<NUM>/s), and especially containing from <NUM> to <NUM> silicon atoms and in particular from <NUM> to <NUM> silicon atoms, these silicones optionally including alkyl or alkoxy groups containing from <NUM> to <NUM> carbon atoms. As volatile silicone oil that may be used in the invention, mention may be made especially of dimethicones with a viscosity of <NUM> and <NUM> cSt, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, heptamethylhexyltrisiloxane, heptamethyloctyltrisiloxane, hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane and dodecamethylpentasiloxane, and mixtures thereof.

Volatile fluoro oils such as nonafluoromethoxybutane or perfluoromethylcyclopentane, and mixtures thereof, may also be used.

It is also possible to use a mixture of the oils mentioned above.

A composition according to the invention may include a non-volatile oil.

For the purposes of the present invention, the term "non-volatile oil" means an oil with a vapour pressure of less than <NUM> Pa and especially oils of high molar mass.

The non-volatile oils may be chosen especially from non-volatile hydrocarbon-based oils, which may be fluorinated, and/or silicone oils.

As non-volatile hydrocarbon-based oil that may be suitable for use in the invention, mention may be made especially of:.

The esters may be chosen especially from especially fatty acid esters, for instance:.

The composition containing the photonic particles may be free of oil, and in particular may contain no non-volatile oil.

The composition including the photonic particles may comprise at least one additive chosen from adjuvants that are common in the cosmetic field, such as fillers, colouring agents, hydrophilic or lipophilic gelling agents, water-soluble or liposoluble active agents, preserving agents, moisturizers such as polyols and especially glycerol, sequestrants, antioxidants, solvents, fragrances, odour absorbers, pH adjusters (acids or bases) and mixtures thereof.

The composition may contain at least one active agent which has a supplementary activity in the field of solar protection, such as antioxidants, bleaching agents in the context of anti-pigmentation and depigmentation, and anti-ageing active agents.

The additive(s) may be chosen from those mentioned in the <NPL>).

The composition according to the invention may be a lotion, a two-phase composition, a cream, a milk, an ointment or a gel, for the skin, the lips, the hair or the nails.

According to another of its aspects, the invention relates to a photoprotective cosmetic composition comprising, in a physiologically acceptable medium, a composition according to the invention as defined above.

The term "physiologically acceptable medium" means a non-toxic medium that may be applied to human keratin materials, in particular the skin, mucous membranes or the integuments.

This medium is adapted to the nature of the support onto which the composition is to be applied, and also to the form in which the composition is intended to be packaged.

The composition may be packaged in any packaging device, in particular made of thermoplastic, or on any support intended for this purpose.

The packaging device may be a bottle, a pump-action bottle, an aerosol flask, a tube, a sachet or ajar.

The photoprotective cosmetic composition may be applied by hand or using an applicator.

The application may also be performed by spraying or projection using, for example, a piezoelectric or aerograph device or by transfer of a layer of composition previously deposited on an intermediate support.

The aqueous dispersion of silica particles (Cosmo S-160NP from JGC) was atomized according to the following process.

The commercial dispersion is used as obtained, or is mixed with water to obtain a mass concentration of particles equal to about <NUM>%.

The dispersion thus obtained was introduced into an atomizer (Niro Minor Production), the injection rate being set at <NUM>/h, the turbine speed being set at <NUM><NUM> rpm and the atomization temperature being set at <NUM>.

The opals obtained are direct opals with a mean size (D <NUM>) of <NUM>, in the form of a dry powder.

The sample is prepared by preparing a solution of the polymer at <NUM>/ml in tetrahydrofuran. The sample is placed in an oven at <NUM> for <NUM> minutes and then in an oscillating shaker for <NUM> minutes to aid dissolution. After visual inspection, the sample appears to be totally dissolved in the solvent.

The sample prepared was analysed using two polypore <NUM>×<NUM> columns (manufactured by Agilent Technologies), a Waters <NUM> chromatographic system, a tetrahydrofuran mobile phase and detection by refractive index. The sample was filtered through a <NUM> nylon filter, before being injected into the liquid chromatograph. The standards used for the calibration are the Easi Vial narrow polystyrene (PS) standards from Agilent Technologies.

Polystyrene standards ranging from <NUM><NUM><NUM> to <NUM> daltons were used for the calibration.

The system is equipped with a PSS SECcurity <NUM> RI detector. The polystyrene calibration curve was used to determine the average molecular weight. The recording of the diagrams and the determination of the various molecular weights were performed by the Win GPC Unichrom <NUM> program.

This method describes the general procedure for determining the melting point of polymers by differential scanning calorimetry. This method is based on the standards ASTM E791 and ASTM D <NUM> and the DSC calibration is performed according to standard ASTM E <NUM>.

In a <NUM>-necked flask equipped with side-blade mixer, an internal thermometer, two funnels, a reflux condenser, and an extension for two other necks, <NUM> of behenyl acrylate, <NUM> of <NUM>-hydroxyethyl acrylate and <NUM> of <NUM>,<NUM>'-azobis(<NUM>-methylbutyronitrile) (Akzo Nobel) were added, over the course of <NUM> minutes at <NUM>, to <NUM> of isopropanol, with stirring, after having removed the oxygen from the system by means of a nitrogen flush for <NUM> minutes. The mixture was stirred at <NUM> for <NUM> hours. The solvent was then removed by vacuum distillation, <NUM> of dilauryl peroxide was then added and the reaction was continued for <NUM> minutes at <NUM>. The step was repeated. The mixture was then cooled to <NUM>, a stream of demineralized water was added and the mixture was then stirred. The water was removed by vacuum distillation.

The following O/W emulsions were prepared:.

Compositions <NUM> to <NUM> are homogeneous and stable for <NUM> months at <NUM>, at room temperature and at <NUM>.

The addition of polymer c) according to the invention makes it possible to increase the SPF very significantly, in contrast with another acrylic polymer not in accordance with the invention.

Composition <NUM> has a high SPF while at the same time having excellent cosmetic properties. The transparency on the skin and the softness are markedly superior for composition <NUM> according to the invention.

Claim 1:
Composition, especially a cosmetic composition, comprising at least:
a) photonic particles having a mean size which denotes the statistical particle size dimension for half the population, referred to as D (<NUM>), of from <NUM> to <NUM> as measured with the method of the description, each including an ordered periodic arrangement of monodisperse nanoparticles or of empty spaces, leading to attenuation of the radiation in the wavelength range extending from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and
b) at least one UV-screening agent, and
c) at least one polymer comprising monomer units of formulae (A) and (B):
<CHM>
in which:
R1, independently at each instance, is chosen from alkyl and alkylene radicals,
and
at least <NUM>% by weight of the groups R1 are radicals chosen from stearyl and behenyl radicals, the weight percentage relating to the sum of all the groups R1 present in the polymer,
and
the weight ratio of the sum of all the hydroxyethyl acrylate units to the sum of all the acrylate units bearing the group R1 ranges from <NUM>:<NUM> to <NUM>:<NUM>,
and the sum of the total of units A and B is at least <NUM>% by weight relative to the total weight of the polymer,
the polymer having a number-average molecular weight Mn ranging from <NUM> to <NUM>/mol.