POLYMER

TECHNICAL FIELD

The present invention relates to the field of cosmetics in form of foam, and especially to the field of low density compositions with whipping texture.

BACKGROUND ART

In the cosmetic field, and more particularly in the field of skincare, photo-protection or makeup, it is known practice from patent application US 2010/033 018 to introduce water-superabsorbent polymers into galenical forms of oil-in-water or water-in-oil emulsion type since they give the textures advantageous sensory effects such as hydrating, freshness or a reduction of tack.

WO2013/087926 disclosed a composition for topical application, comprising at least one aqueous phase, at least one fatty phase, at least one superabsorbent polymer and hydrophobic silica aerogel particles with a specific surface area per unit of mass (S _M ). The products as such can apply uniformly onto the skin and do not pill after application. The other key property of the cosmetic products which is of great interest of the consumers is the texture, such as softness and lightness. Consumers, especially those in the areas where the weather is generally warm and the humidity is relatively high, are especially in favor of products with light texture.

EP1925282 disclosed a low density cosmetic formulation with air incorporated in the product to give the products a lighter texture and the appearance of a foam.

Foams are generally thermodynamically unstable two- or three-phase systems in which bubbles of gas (generally air, nitrogen) are dispersed. In general, they have a low density at 20°C of generally between 0.3 and 0.95. The stability of a foam depends greatly on that of the walls which separate the bubbles: the interfaces. The emulsion, the external phase of the emulsion/air dispersion, constitutes these interfaces. They are very thin and therefore very fragile. The stability of the foam is defined by its ability to retain its structure (number of bubbles, size of the bubbles) over time. Efforts had been made to stabilize the foam texture products to be packaged in the containers commonly used in the cosmetic field, for example, jars. WO2013/124430 disclosed a low density composition in the form of a foam with good stabilities.

However, none of the prior arts disclosed a novel composition with desired textures, sensory effects, and improved stabilities over time, temperature, as well as the transportation variations.

There thus exists a need for a novel composition possessing lighter texture and excellent sensory effect, such as hydrating, freshness or a reduction of tack, and which has improved stabilities over varied time, temperature, and transportation situations, for example, vibration, or high pressure. DISCLOSURE OF INVENTION

Therefore, the present invention relates to an oil-in-water composition in the form of a foam having a dispersed fatty phase in a continuous aqueous phase, having a density of 0.3 to 0.95, wherein the composition comprises: a) at least one starch phosphate; b) at least one superabsorbent polymer; c) at least one hydrophilic gelling polymer chosen from hydrophilic anionic associative polymers, hydrophilic anionic non associative polymers, or a mixture thereof; and d) at least one surfactant.

The other subject of the present invention is a process for making up/caring for the keratin materials, for example the skin, in particular the face and the lips, by applying to the keratin materials the composition of the present invention.

The term "keratin material" means the skin (of the body, face and around the eyes), hair, eyelashes, eyebrows, bodily hair, nails, lips or mucous membranes. In particular, it means the skin, for example the skin of the face or the lips. The term "long term stability" means a composition that does not undergo any significant change in its structure or properties for at least one month after its manufacture and especially for at least two months after its manufacture.

DETAILED DESCRIPTION OF THE INVENTION Density

The density of the compositions ranges from 0.3 to 0.95 and preferably from 0.5 to 0.9, even more preferably from 0.6 to 0.9. It is measured at 20°C using a Gardener pycnometer, which is a metal pycnometer, with a volume of 100 ml and a cylindrical shape. Method of measurement: the density of a product is the ratio of the weight of a given volume of this product to the weight of the same volume of water under defined temperature conditions; in this case the temperature is 20°C.

The pycnometer is weighed before and after filling, firstly with demineralized water, and then with the product to be analysed. The density value is calculated according to the following equation:

M ₂ - M ₀ d (T°C) =

where:

M ₀ is the weight of the empty pycnometer (grams)

ΜΊ is the weight of the pycnometer + water at T°C (grams)

M ₂ is the weight of the pycnometer + product at T°C (grams) Preparation processes

The compositions according to the invention can be prepared according to a process comprising the following steps: a) the aqueous phase and the fatty phase for the emulsification are mixed under hot conditions at a temperature greater than 60°C; b) the emulsion is left to cool and, starting from 50°C, mechanical stirring is carried out, in the presence of an inert gas chosen from air, nitrogen, carbon dioxide or oxygen, until the desired density is reached.

According to one particular embodiment of the invention, a whipping machine, in particular a pressurized continuous whipping machine such as of the Howden B.V. Mondomix type, which is known in the food-processing industry, will be used for step b). The emulsion is melted with stirring in the melting vessel. It is then pumped so as to arrive at a mixing head (rotor/stator assembly) with a given amount of air. The rotation of the rotor will incorporate the air into the emulsion and form the foam. A back-pressure system can be used to increase the incorporation of the air into the emulsion. .

This type of whipping machine makes it possible in particular to adjust the following parameters: the emulsion temperature, the emulsion input flow rate, the emulsion input pressure, the air flow rate, the rotor speed, the temperature of the mixing head by means of a thermostatic jacket and the pressure of the mixing head (back-pressure system). The emulsion input flow rate is preferably from 5 to 200 ml/minute.

The emulsion input pressure preferably ranges from 0.1 to 7 bar.

The air flow rate preferably ranges from 5 to 320 ml/minute.

The rotor speed preferably ranges from 200 to 1600 rpm.

The pressure of the mixing head is preferably from 1 to 4.5 bar. The degree of expansion of a foam according to the invention is generally less than 200%, preferably less than 150% and preferentially less than 100%.

The degree of expansion DegE is measured by means of the density before expansion and the density after expansion, according to the following formula:

DegE = 100 X (Dcream before expansion - Dcream after expansion) / Dcream after expansion Aqueous phase

The composition of the present invention comprises a continuous aqueous phase. The continuous aqueous phase comprises water. The continuous aqueous phase can also comprise a polyol which is miscible with water at ambient temperature (25°C) chosen in particular from polyols having in particular from 2 to 20 carbon atoms, preferably having from 2 to 10 carbon atoms and preferentially having from 2 to 6 carbon atoms, such as glycerol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, dipropylene glycol or diethylene glycol; glycol ethers (having in particular from 3 to 16 carbon atoms), such as mono-, di- or tripropylene glycol (Ci-C ₄ )alkyl ethers, or mono-, di- or triethylene glycol (CrC ₄ )alkyl ethers; and mixtures thereof.

In particular, the composition of the invention may comprise a continuous aqueous phase in an amount ranging from 10% to 99% by weight, especially from 20% to 90% by weight and more particularly from 30% to 85% by weight relative to the total weight of the composition.

Starch phosphates

The composition of the present invention comprises at least one starch phosphate, or a mixture thereof.

The starch phosphates that may be used in the present invention are more particularly macromolecules in the form of polymers formed from elemental units that are anhydroglucose units. The number of these units and their assembly make it possible to distinguish amylose (linear polymer) and amylopectin (branched polymer). The relative proportions of amylose and of amylopectin, and their degree of polymerization, vary as a function of the plant origin of the starches. The starch molecules used in the present invention may originate from a plant source such as cereals, tubers, roots, legumes and fruit. Thus, the starch(es) may originate from a plant source chosen from corn, pea, potato, sweet potato, banana, barley, wheat, rice, oat, sago, tapioca and sorghum. The starch is preferably derived from corn.

It is also possible to use the starch hydrolysates mentioned above. Starch phosphates are generally in the form of a white powder, whose elemental particle size ranges from 3 to 100 microns.

The starches used in the composition of the invention may be chemically modified via one or more of the following reactions: pregelatinization, oxidation, crosslinking, esterification, heat treatments. In particular, the crosslinking reaction is preferred. This reaction is performed by crosslinking with functional agents capable of reacting with the hydroxyl groups of the starch molecules, which will thus bond together (for example with glyceryl and/or phosphate groups).

More particularly, the starch phosphate is chosen from: - monostarch phosphates of formula (I),

Am-0-PO-(OX) ₂ (I), distarch phosphates of formula (II),

Am-0-PO-(OX)-0-Am (II), tristarch phosphates of the formula (III), Am-0-PO-(0-Am) ₂ (lll) or a mixture thereof, wherein:

Am means starch;

X represents alkali metals (for example sodium or potassium), alkaline-earth metals (for example calcium or magnesium), ammonium salts, amine salts, for instance those of monoethanolamine, diethanolamine, triethanolamine, 3-amino-1 ,2-propanediol, or ammonium salts derived from basic amino acids such as lysine, arginine, sarcosine, ornithine or citrulline.

Preferably, the starch phosphate of the present invention is chosen from distarch phosphates of formula (II) described above. Mentions may be made of the distarch phosphates, for example, the products sold under the references Prejel VA-70-T AGGL (gelatinized hydroxypropyl cassava distarch phosphate), Prejel TK1 (gelatinized cassava distarch phosphate) and Prejel 200 (gelatinized acetyl cassava distarch phosphate) by the company Avebe, or Structure Zea (gelatinized hydroxypropyl corn distarch phosphate) by the company Akzo Nobel. Preferably, the starch phosphates present in the composition of the present invention in an amount ranging from 0.5% to 10% by weight, preferably from 1 % to 7% by weight, and better still from 2% to 5% by weight, relative to the total weight of the composition. Superabsorbent polymers

The term "superabsorbent polymer" is intended to mean a polymer that is capable in its dry form of spontaneously absorbing at least 20 times its own weight of aqueous fluid, in particular of water and in particular distilled water. Such superabsorbent polymers are described in the publication "Absorbent polymer technology, Studies in polymer science 8" by L. Brannon- Pappas and R. Harland, published by Elsevier, 1990.

These polymers have a large capacity for absorbing and retaining water and aqueous fluids. After absorption of the aqueous liquid, the polymer particles thus engorged with aqueous fluid remain insoluble in the aqueous fluid and thus conserve their individualized particulate state. The superabsorbent polymer may have a water-absorbing capacity ranging from 20 to 2000 times its own weight (i.e. 20 g to 2000 g of absorbed water per gram of absorbent polymer), preferably from 30 to 1500 times and better still from 50 to 1000 times. These water absorption characteristics are defined under normal temperature (25°C) and pressure (760 mmHg, i.e. 100000 Pa) conditions and for distilled water. The value of the water-absorbing capacity of a polymer may be determined by dispersing 0.5 g of polymer(s) in 150 g of a water solution, waiting for 20 minutes, filtering the unabsorbed solution through a 150 μηη filter for 20 minutes and weighing the unabsorbed water.

The superabsorbent polymer used in the composition of the invention is in the form of particles. Preferably, the superabsorbent polymer has, in the dry or nonhydrated state, an average size of less than or equal to 100 μητι, preferably less than or equal to 50 μητι, ranging for example from 10 to 100 μητι, preferably from 15 to 50 μητι, and better still from 20 to 30 μηη.

The average size of the particles corresponds to the weight-average diameter (D ₅₀ ) measured by laser particle size analysis or another equivalent method known to those skilled in the art.

Once hydrated, these particles swell, forming soft particles which have an average size that can range from 10 μηη to 1000 μητι, preferentially from 20 μηη to 500 μηη and even more preferentially from 50 μηη to 400 μηη.

Preferably, the superabsorbent polymers used in the present invention are in the form of spherical particles.

Mention may be made in particular of absorbent polymers chosen from: - crosslinked sodium polyacrylates, for instance those sold under the names Octacare X100, X1 10 and RM100 by the company Innospec Active Chemicals, those sold under the names Flocare GB300 and Flosorb 500 by the company SNF, those sold under the names Luquasorb 1003, Luquasorb 1010, Luquasorb 1280 and Luquasorb 1 1 10 by the company BASF, those sold under the names Water Lock G400 and G430 (INCI name: Acrylamide/Sodium acrylate copolymer) by the company Grain Processing, or else Aquakeep ^® 10 SH NF proposed by the company Sumitomo Seika,

- starches grafted with an acrylic polymer (homopolymer or copolymer) and in particular with sodium polyacrylate, such as those sold under the name Sanfresh ST-100MC by the company Sanyo Chemical Industries or Makimousse 25 or Makimousse 12 by the company Daito Kasei (INCI name: Sodium polyacrylate starch),

- hydrolyzed starches grafted with an acrylic polymer (homopolymer or copolymer) and in particular acryloacrylamide/sodium acrylate copolymer, such as those sold under the names Water Lock A-240, A-180, B-204, D-223, A-100, C-200 and D-223 by the company Grain Processing (INCI name: Starch/acrylamide/sodium acrylate copolymer),

- polymers based on starch, on gum and on cellulose derivative, such as the product containing starch, guar gum and sodium carboxymethylcellulose, sold under the name Lysorb 220 by the company Lysac,

- and mixtures thereof.

The superabsorbent polymers used in the present invention may be crosslinked or noncrosslinked. They are preferably chosen from crosslinked polymers.

The superabsorbent polymers used in the present invention are preferably crosslinked acrylic homopolymers or copolymers, which are preferably neutralized, and which are in particulate form. Preferably, the superabsorbent polymer is chosen from crosslinked sodium polyacrylates, preferably in the form of particles with an average size (or average diameter) of less than or equal to 100 microns, more preferably in the form of spherical particles. These polymers preferably have a capacity for absorbing water containing 0.9% of NaCI of from 10 to 100 g/g, preferably from 20 to 80 g/g and better still from 30 to 80 g/g. The superabsorbent polymer(s) may be present in the composition of the invention in an amount ranging, for example, 0.05% to 10% by weight, preferably from 0.1 % to 5% by weight, more preferably from 0.2% to 3% by weight, relative to the total weight of the composition.

Hydrophilic gelling polymer The composition according to the invention comprises at least one hydrophilic gelling polymer chosen from hydrophilic anionic associative polymers, hydrophilic anionic non associative polymers, or a mixture thereof.

For the purposes of the present patent application, the term "hydrophilic gelling polymer" means a polymer that is capable of gelling the aqueous phase of the compositions according to the invention.

The hydrophilic gelling polymer is present in the aqueous phase of the composition. More particularly, this hydrophilic gelling polymer may be chosen from: i. Hydrophilic anionic associative polymers

Hydrophilic anionic associative polymers of the present invention are water-soluble polymers capable, in an aqueous medium, of reversibly associating together or with other molecules.

Their chemical structure comprises hydrophilic zones and hydrophobic zones characterized by at least one fatty chain.

The hydrophilic anionic associative polymer of the present invention preferably comes from the copolymerization between 1 ) and 2): 1 ) at least one ethylenically unsaturated mono or dicarboxylic acid monomer substituted by at least one, linear or branched, (d-dojalkyl group; and

2) at least one associative monomer which is an ester of formula (IV):

A-0-(Alk-0) _z -(CH ₂ )w- ^a (IV)

Formula (IV) wherein: A represents a ethylenically unsaturated acyclic residue, optionally containing an additional carboxylic group or it salt, wherein said additional carboxylic group may be esterified with a linear or branched (CrC ₂ o)alkyl group; R ^a represents an alkyl a linear or branched (Ci-C ₃₀ )alkyl group, alkylaryl or arylalkyl group having from 1 to 30 carbon atoms wherein the alkyl group is linear or branched, preferably R ^a represents (Ci-C ₂ o)alkyl group, alkylphenyl or phenylakyl group having from 1 to 20 carbon atoms wherein the alkyl group is linear or branched; Alk represents a linear or branched (Ci-C ₆ )alkylene group, particularly Alk represents -CH ₂ -CH(R ^b )- wherein R ^b represents a hydrogen atom, or a (Ci-C ₄ )alkyl group such as methyl or ethyl group; z is an integer comprised inclusively between 0 and 50; w is an integer comprised inclusively between 0 and 30; with the proviso that (IV) contains at least on carboxyl group C(0)OH, or C(0)0-Q ⁺ wherein Q ⁺ represents cations chosen from an alkali metal, an alkaline earth metal, or ammonium.

By polymerization of 1 ) and 2), it must be understood a copolymerization between at least one monomer 1 ) with at least one monomer 2).

According to an embodiment of the invention the copolymer comes from the polymerization between at least one ethylenically unsaturated mono or dicarboxylic acid monomer (a) and at least one associative monomer which is an ester of formula (IV) as defined herein before or (b):

Formulas (a) and (b) wherein:

R' _a and R' _b , identical or different, represent a hydrogen atom, or a linear or branched (C _r C ₆ )alkyl group, preferably R' _a and R' _b represent hydrogen atom; R'c and R" _c , identical or different, represent a hydrogen atom, or a linear or branched (C C ₆ )alkyl group, a C(0)OX group, or a -alk-C(0)OX group wherein X represents a hydrogen atom, an alkali metal, alkaline earth metal, or ammonium and -alk- represents a (Ci-C ₆ )alkylene group such as methylene group, preferably R' _c and/or R" _c represent a hydrogen atom or a methyl group;

Ri represents a hydrogen atom, an alkali metal, alkaline earth metal, or a (Ci-C ₆ )alkyl group;

R ₂ represents a, linear or branched, (C ₆ -C ₄ o)alkyl group, preferably a (C ₁₀ -C ₃ o)alkyl group; n is an integer comprised inclusively between 5 and 100, particularly between 10 and 50, more particularly between 20 and 40, preferably between 20 and 30 such as 25; with the proviso that (a) or (b) contain at least on carboxyl group C(0)OH, or C(0)0-Q ⁺ wherein Q ⁺ represents cation chosen from an alkali metal, alkaline earth metal or ammonium.

Particularly R' _a , R' _b represent a hydrogen atom and R' _c , and R" _c represent a hydrogen atom or a methyl group and Ri represents a hydrogen atom, an alkali metal, alkaline earth metal.

According to another variant R' _a , R' _b , and R' _c , represent a hydrogen atom and R" _c represents a group -alk-C(0)OX such as -CH ₂ -C(0)OX wherein X is as defined herein before.

According to a particular embodiment of the invention, the hydrophilic anionic associative polymer contains units (A) and/or (B):

(A) wherein:

R'a, R' _b , R'c, R"c are as defined herein before; x represents an integer, preferably more than 100, more preferably between 100 and 10000; y represents an integer, preferably more than 100, more preferably between 100 and 10000; and x + y represents an integer, preferably > 200, more preferably between 200 and 20000.

According to a preferred embodiment, the anionic associative polymer i) of the present invention has a molecular weight of more than 100000, preferably between 200000 and 8000000.

According to a preferred embodiment, in formula (A) and (B), Ri represents a hydrogen atom, an alkali metal, or an alkaline earth metal.

As example of copolymer (a) / (b) as defined herein before, usable in the invention, we may mention: acrylates/palmeth-25 acrylate copolymer, such as the products commercially available from 3V under the trade name Synthalen ^® W2000, acrylates/beheneth-25 methacrylate copolymer, such as the products commercially available from Rohm And Haas (Dow Chemical) under the trade name Acylun ^™ 28, acrylates/steareth-20 methacrylate copolymer, such as the products commercially available from Rohm and Haas (Dow Chemical) under the trade name Aculyn ^™ 22 polymer, acrylates /steareth-20 itaconate copolymer, such as the products commercially available from AkzoNobel under the trade name Structure 2001 , acrylates /ceteth- 20 itaconate copolymer, such as the products commercially available from AkzoNobel under the trade name Structure 3001 , acrylates /ceteth-20 methacrylate copolymer, acrylate /beheneth-25 itaconate copolymer, acrylate /palmeth-25 methacrylates copolymer, acrylate/steareth-50 acrylate copolymer, acrylates/palmeth-25 itaconate copolymer, such as the products commercially available from Sigma-3V under the trade name Polygel W 40, and mixtures thereof. Among the above said hydrophilic anionic associative polymers, acrylates/beheneth-25 methacrylate copolymer, such as the products commercially available from Rohm And Haas (Dow Chemical) under the trade name Acylun™ 28 is preferred. ii. Hydrophilic anionic non associative polymers The hydrophilic anionic non associative polymer contains hydrophilic units of unsaturated olefinic carboxylic acid, and potentially in the presence of at least one cross-linking agent.

The hydrophilic anionic non associative polymer is chosen from those obtained from at least one monomer of formula (V) below:

Formula (V) in which R' _a and R' _c and Ri are as defined herein before, more specifically R' _a represents a hydrogen atom, R' _c represents a hydrogen atom, a methyl group or a ethyl group with the proviso that at least one monomer is such that Ri represents a hydrogen atom, an alkali metal, alkaline earth metal.

According to a particular embodiment, the polymer is a polymer obtained from monomer (V) as previously defined with Ri represents a hydrogen atom, an alkali metal, alkaline earth metal.

According to another embodiment, the hydrophilic anionic non associative polymer is a homopolymer obtained from acrylic acid monomers or methacrylic acid monomers, preferably acrylic acid monomers.

According to the present invention, the hydrophilic anionic non associative polymer can be cross linked.

By crosslinking agent it must be understood an agent able to make links between molecular chains to form a three-dimensional network of connected molecules (co) or (homo)polymers.

The said crosslinking agent is a monomer more specifically containing at least one group ethylenyl or allylether group as the following formula (c) or (d): formula (c) or (d) wherein R" _c is as defined herein before, more particularly represent H or methyl group, with at least one other polymerizable group whose unsaturated bonds are not conjugated to each other. Mentions may be made of derivatives of ethylene glycol di(meth)acrylate such as ethylene glycol diacrylate, di(ethylene glycol) diacrylate, tetra(ethylene glycol) diacrylate, ethylene glycol dimethacrylate, di(ethylene glycol) dimethacrylate, tri(ethylene glycol) dimethacrylate, derivatives of methylenebisacrylamide such as N,N.- methylenebisacrylamide, N,N. -methylenebisacrylamide, N,N.-(1 ,2- dihydroxyethylene)bisacrylamide, formaldehyde-free crosslinking agent such as N- (1-hydroxy- 2,2-dimethoxyethyl)acrylamide, and divinylbenzene, and (poly)allylether.

Preferably the monomers (V) are polymerized in a presence of cross-linking agent especially in a presence of (poly)allyl ethers in particular, (poly)allyl sucrose and (poly)allyl pentaerylthritol, such as carbomer which corresponds to a homopolymer of acrylic acid crosslinked with an allyl ether of pentaerythritol, an allyl ether of sucrose, or an allyl ether of propylene.

The hydrophilic anionic non associative polymer is preferably chosen from carbomer. Carbomer is a crosslinked homopolymer of acrylic. This carbomer are for example sold under the trade name Carbopol ^® 940, Carbopol ^® 941 , Carbopol ^® 980, Carbopol ^® 981 , preferably Carbopol ^® 981.

According to a preferred embodiment, the present invention comprises, in an aqueous phase, as hydrophilic gelling polymers, at least one hydrophilic anionic associative polymer, and at least one hydrophilic anionic non associative polymer.

More preferably, the composition of the invention comprises, in an aqueous phase, as hydrophilic gelling polymers, at least one hydrophilic anionic associative polymer chosen from the copolymer of the formulas (a) / (b) as defined before, for example acrylates/beheneth-25 methacrylate copolymer, and at least one hydrophilic anionic non associative polymer chosen from those obtained from at least one monomer of formula (V) as defined before, for example carbomer.

Preferably the at least one hydrophilic gelling polymer is present in the composition of the invention in an active material content ranging, for example, from 0.01 % to 20% by weight, preferably from 0.05% to 10% by weight, more preferably from 0.1 % to 5% by weight, relative to the total weight of the composition.

Fatty phase

The composition according to the present invention comprises at least one fatty phase.

The fatty phase according to the present invention is a dispersed phase. The fatty phase of the present invention comprises at least one oil.

The term "oil" means any fatty substance that is in liquid form at room temperature (20-25°C) and at atmospheric pressure (760 mmHg).

The fatty phase(s) that is suitable for preparing the cosmetic compositions according to the invention may comprise hydrocarbon-based oils, silicone oils, fluoro oils or non-fluoro oils, or mixtures thereof.

According to a preferred embodiment, the composition of the present invention comprises hydrocarbon-based oils.

The oils may be volatile or non-volatile.

The term "non-volatile oil" means oil that remains on the keratin materials, especially the skin and the lips at room temperature (20-25°C) and atmospheric pressure (760 mmHg). More specifically, non-volatile oil has an evaporation rate strictly less than 0.01 mg/cm ² /min.

To measure this evaporation rate, 15 g of oil or of oil mixture to be tested are placed in a crystallizing dish 7 cm in diameter, which is placed on a balance in a large chamber of about 0.3 m ³ that is temperature-regulated, at a temperature of 25°C, and hygrometry-regulated, at a relative humidity of 50%. The liquid is allowed to evaporate freely, without stirring it, while providing ventilation by means of a fan (Papst-Motoren, reference 8550 N, rotating at 2700 rpm) placed in a vertical position above the crystallizing dish containing said oil or said oil mixture, the blades being directed towards the crystallizing dish, 20 cm away from the bottom of the crystallizing dish. The mass of said oil or oil mixture remaining in the crystallizing dish is measured at regular intervals. The evaporation rates are expressed in mg of oil evaporated per unit of area (cm ² ) and per unit of time (minute).

The term "volatile oil" means any non-aqueous medium that is capable of evaporating on contact with the keratin materials, especially the skin and the lips in less than one hour, at room temperature (20-25°C) and atmospheric pressure (760 mmHg). The volatile oil is a cosmetic volatile oil, which is liquid at room temperature. More specifically, a volatile oil has an evaporation rate of between 0.01 and 200 mg/cm ² /min, limits included.

For the purposes of the present invention, the term "silicone oil" means oil comprising at least one silicon atom, and especially at least one Si-0 group.

As silicone oils, mention may be made of: linear or cyclic volatiles oils, especially those with a viscosity of less than or equal to 8 centistokes (cSt) (8 ^χ 10-6 m ² /s), and especially containing from 2 to 10 silicon atoms and in particular from 2 to 7 silicon atoms, these silicones optionally comprising alkyl or alkoxy groups containing from 1 to 10 carbon atoms; of linear or cyclic non-volatile polydimethylsiloxanes (PDMS); polydimethylsiloxanes comprising alkyl, alkoxy or phenyl groups, which are pendant or at the end of a silicone chain, these groups containing from 2 to 24 carbon atoms; phenyl silicones, for instance phenyl trimethicones, phenyl dimethicones, phenyl trimethylsiloxy diphenyl siloxanes, diphenyl dimethicones, diphenyl methyldiphenyl trisiloxanes and 2-phenylethyl trimethylsiloxy silicates, and mixtures thereof.

The term "fluoro oil" means oil comprising at least one fluorine atom.

The fluoro oils that may be used according to the invention may be chosen from fluorosilicone oils, fluoro polyethers and fluorosilicones as described in document EP-A-847 752, and perfluoro compounds.

According to the invention, the term "perfluoro compounds" means compounds in which all the hydrogen atoms have been replaced with fluorine atoms. According to one particularly preferred embodiment, the fluoro oil according to the invention is chosen from perfluoro oils.

The term "hydrocarbon-based oil" means oil mainly containing hydrogen and carbon atoms. The oils may optionally comprise oxygen, nitrogen, sulfur and/or phosphorus atoms, for example in the form of hydroxyl or acid radicals.

As hydrocarbon-based oils, mention may be made of: hydrocarbon-based oils of animal origin, hydrocarbon-based oils of plant origin, for example Beta-carotene sold under the tradename Betatene 30% OLV by Cognis (BASF), Simmondsia Chinensis (Jojoba) Seed oil sold under the tradename Jojoba Oil Golden by Desert Whale, Rosa Canina Fruit Oil sold under the tradename

Rosehip Seed Oil by Nestle World Trade Co; linear or branched hydrocarbons of mineral or synthetic origin; synthetic ethers containing from 10 to 40 carbon atoms; synthetic esters, for example Caprylic/Capric Triglyceride sold under the tradename Myritol ^® 318 by Cognis (BASF), Isononyl Isononanoate sold under the tradename

Isononanoate D'isononyle by Stearinerie Dubois, Dicaprylyl Carbonate sold under the tradename Cetiol ^® CC by Cognis (BASF), isopropyl isostearate sold under the tradename Wickenol 131 by the company ALZO;

- fatty alcohols that are liquid at room temperature, with a branched and/or unsaturated carbon-based chain containing from 12 to 26 carbon atoms;

- C ₁₂ -C ₂ 2 higher fatty acids; and mixtures thereof.

Preferably, the composition of the present invention comprises at least one fatty phase presenting in the composition in an amount ranging from 1 % to 90% by weight, preferably from 5% to 70% by weight, and more preferably from 10% to 30% by weight, relative to the total weight of the composition.

Surfactants

The composition of the present invention comprises at least one surfactant. The surfactants may be chosen from anionic surfactants, cationic surfactants, amphoteric or zwitterionic surfactants, nonionic surfactants, or a mixture thereof.

Preferably the surfactants are chosen from anionic surfactants, nonionic surfactants, or a mixture thereof.

Preferably the surfactants are chosen from: anionic surfactants having a HLB value of greater than or equal to 8, according to Griffin's method, a nonionic surfactants being esters of polyols and of fatty acids possessing a saturated or unsaturated chain comprising, for example, from 8 to 24 carbon atoms and better still from 12 to 22 carbon atoms, and their oxyalkylenated derivatives, or a mixture thereof.

Preferably, the composition comprises at least one surfactant being a mixture of anionic surfactants having a HLB value of greater than or equal to 8, according to Griffin's method, and a nonionic surfactants being esters of polyols and of fatty acids possessing a saturated or unsaturated chain comprising, for example, from 8 to 24 carbon atoms and better still from 12 to 22 carbon atoms, and their oxyalkylenated derivatives.

The HLB value of the anionic surfactant according to GRIFFIN is defined in J. Ploughshare. Cosm. Chem. 1954 (volume 5), pages 249-256.

Preferably, the anionic surfactant has a HLB value between 8 and 20 according to Griffin's method, at the temperature of 25 °C, more preferably between 10 and 15 according to Griffin's method, at the temperature of 25 °C.

Suitable anionic surfactants of the present invention may be chosen from alkyl sulphates, alkyl ether sulphates and their salts, alkyl sulphoacetates, alkyl sulphosuccinates, polypeptides which are obtained, for example, by condensation of a fatty chain with cereal amino acids and in particular wheat and oat amino acids, amino acid derivatives, sulphonates, for example a-olefin sulphonates, isethionates, in particular acyl isethionates, phosphoric esters and salts thereof, or a mixture thereof.

Preferably, the anionic surfactant is chosen from phosphoric esters and salts, in particular phosphoric esters and salts of C ₂ -C ₃ o linear or branched, saturated or unsaturated alcohols, more preferably phosphoric esters and salts of C ₄ -C ₂ 4, even more preferably C ₆ -C ₁₈ , for example C ₁₆ or C ₁₈ linear or branched, saturated or unsaturated alcohols,

Mentions may be made of the preferred anionic surfactant, such as DEA oleth-10 phosphate (Crodafos N 10N from the company Croda) or potassium cetyl phosphate (Amphisol ^® K from DSM Nutritional Products), more preferably the anionic surfactant is potassium cetyl phosphate. Suitable nonionic surfactants according to the present invention are esters of polyols and of fatty acids possessing a saturated or unsaturated chain comprising, for example, from 8 to 24 carbon atoms and better still from 12 to 22 carbon atoms, and their oxyalkylenated derivatives. Preferably, the nonionic surfactant is chosen from esters of glycerol and of a C ₈ -C ₂₄ fatty acid, and their oxyalkylenated derivatives; esters of polyethylene glycol and of a C ₈ -C ₂₄ fatty acid, and their oxyalkylenated derivatives; esters of sorbitol and of a C ₈ -C ₂₄ fatty acid, and their oxyalkylenated derivatives; ethers of fatty alcohols; ethers of a sugar and of C ₈ -C ₂₄ fatty alcohols, and their mixtures.

Mention may in particular be made, as ester of glycerol and of a C ₈ -C ₂₄ fatty acid, of glyceryl stearate (glyceryl mono-, di- and/or tristearate) (CTFA name: glyceryl stearate) or glyceryl ricinoleate, and their mixtures, for example the product sold under the trade name Cerasynt SD by ISP.

Preferably the nonionic surfactant is glyceryl stearate.

According to a preferred embodiment, the composition of the present invention comprises at least one surfactant being a mixture of phosphoric esters and salts of C ₂ -C ₃₀ linear or branched, saturated or unsaturated alcohols and esters of polyols and of fatty acids possessing a saturated or unsaturated chain comprising, from 8 to 24 carbon atoms and better still from 12 to 22 carbon atoms, preferably a mixture of phosphoric esters and salts, and esters of glycerol and of C ₈ -C ₂₄ fatty acids, more preferably a mixture of potassium cetyl phosphate and glyceryl stearate.

Preferably, the surfactant is present in the composition of the present invention in an amount ranging from 0.05% to 10% by weight, preferably from 0.1 % to 5% by weight, relative to the total weight of the composition.

Galenic form

The composition according to the present invention is formed by incorporating a gas into a cosmetic mixture according to any embodiment described herein. The gas may be incorporated in any suitable manner including, but not limited to simple mixing in contact with an atmosphere containing a suitable gas or even ambient conditions, aeration or other methods of injecting a gas into or through the mixture and by use of gas expansion devices known in the art or which are to be developed.

In several preferred embodiments of the present invention, the introduction of the gas, preferably air, into the cosmetic mixture is carried out in an expansion device comprising a mixing head having a rotor and a stator, such as, for example, the "Minimondo-type Mondomixer" commercially available from Mondomix. The mixture is transported via a pump into the expansion head, where the mixture and the gas are simultaneously injected and homogeneously mixed by virtue of the cutting action of the lugs of the rotor and stator of the device, which provide even distribution of the gas in the mixture. The speed of the rotor of the device, the temperature of the vessel, gas pressure and flowrate of the gas are appropriately regulated. The pressure of the mixing head is regulated by a pressure regulator. The flow rate of the low density cosmetic formulation at the outlet of the device depends on the rate of the pump at the vessel outlet.

Preferably, in the expansion device, the stirring speed during the introduction of the gas is approximately 100 to 1000 revolutions/minute and more preferably, approximately 800 revolutions/minute. The temperature of the vessel is approximately room temperature (e.g., about 25 to 30°C), although heating can be carried out if desired. The gas pressure is approximately 2-5 bar, and preferably about 3 bar. Backpressure can be about 1.5 bar. Bulk flowrate of the mixture can be about 20-25 kg/hour. The gas bubbles in the low density cosmetic formulation obtained according to the embodiments of the invention using a gas expansion device can generally have a size ranging from about 20 μηη to about 6000 μητι, preferably from about 100 μηη to about 3000 μηη. In general, it is advantageous from an aesthetic perspective that at least a protion of the bubbles are visible without magnification.

Methods in accordance with other embodiments of the invention include treating hair, nails and/or skin with a low density cosmetic formulation according to one or more embodiments of that aspect of the present invention. Such methods generally include providing a hair or skin substrate to be treated, preferably hair, and contacting the substrate with a low density cosmetic formulation according to an embodiment of the invention. Methods in accordance with this aspect of the invention can include application of the cosmetic formulation to the substrate with any of direct application to the dry substrate, wetting, lathering, rinsing, allowing to stand followed by rinsing, blow-drying, dyeing, lightening, highlighting, perming, relaxing, making up skin, nails, lips and/or hair, moisturizing and massaging. Any of these additional steps or combinations thereof can be carried out prior to, simultaneously with or subsequent to the application of the low density cosmetic formulation.

Additives

In a particular embodiment, a composition according to the invention further comprises at least one compound chosen from hydrophilic solvents, lipophilic solvents, additional oils, and mixtures thereof.

A cosmetic composition according to the invention may also comprise any additive usually used in the field under consideration, chosen, for example, from fillers or viscosity increasing agents, oil dispersed gelling agents, additional gums, additional resins, additional thickening agents, structuring agents, dispersants, antioxidants, essential oils, preserving agents, fragrances, neutralizers, antiseptics, additional UV-screening agents, cosmetic active agents, such as vitamins, moisturizers, emollients or collagen-protecting agents, and mixtures thereof.

Mentions may be made, to the oil dispersed gelling agents, for example fatty alcohols such as the product cetearyl alcohol, which, for example, sold under the tradename Lanette O ^® OR by the company Cognis (BASF).

It is a matter of routine operations for a person skilled in the art to adjust the nature and amount of the additives present in the compositions in accordance with the invention such that the desired cosmetic properties and stability properties thereof are not thereby affected.

Method and use The composition of the present invention can be used for a non-theraputic process, such as a cosmetic process or method, for making up/caring for the keratin materials, such as the skin, in particular the face and the lips, by being applied to the skin, especially the face and the lips.

The present invention also relates to a use of the composition according to the present invention, as it is or in cosmetic product for making up/caring for/cleansing/make up removing products for the skin, especially for the face and the lips.

The examples that follow are aimed at illustrating the compositions and processes according to this invention, but are not in any way a limitation of the scope of the invention.

EXAMPLES Example 1 : formulation example

The following formulas were prepared:

% wt by active ingredient

Comparative

Phase INCI name Comparative formula 1

Invention Invention formula 2

(without

formula 1 formula 2 (without superabsorbent

starch) polymer)

Potassium Cetyl Phosphate

(Amphisol ^® K from DSM 0.40 0.40 0.40 0.40 Nutritional Products)

A1

Colorants 1.00 1.00 1.00 1.00

Water QS 100 QS 100 QS 100 QS 100

Acrylates/Beheneth-25

Methacrylate copolymer

0.30 0.30 0.30 0.30 (Aculyn ^™ 28 from Rohm

And Haas, DOW Chemical)

A2 Carbomer (Carpopol ^®

0.20 0.20 0.20 0.20 981 Polymer from Lutrizol)

Hydroxypropyl starch

phosphate (Structure ZEA 3.00 2.00 3.00 0 from Akzo Nobel)

Sodium Acrylates

A3 crosspolymer-2 (and) water 0.50 0 0 0.50

(and) Silica (Aquakeep ^®

10SH-NFC from Sumitomo Seika)

Sodium polyacrylate starch

(Makimousse 12 from Daito 0 0.50 0 0

Kasei)

Fragrance 0.20 0.20 0.20 0.20

Isopropyl isostearate

5.50 5.50 5.50 5.50

(Wickenol 131 from ALZO)

B Cetearyl alcohol (Lanette

0 ^® OR from Cognis 0.80 0 0.80 0.80

(BASF))

Glyceryl stearate (Cerasynt

0.80 0.80 0.80 0.80

SD from ISP)

Remarks: Comparative formula 1 does not contain superabsorbent polymer; comparative formula 2 does not contain modified starch.

Method of preparation (the formulas were prepared using the homogenizer with the brand TURBOTEST Type V2004 from the company VMI RAYNERI): The aqueous phase A1 was heated to 70°C, the fatty phase B was mixed and heated to 70°C, the phase B was added into phase A1 at 70°C, using the homogenizer for 15 minutes; phase A2 was added into the mixture at 70°C using the homogenizer for 15 minutes. Then the mixture was cooled to 25°C, and the phase A3 was added thereto.

Procedure: The invention formulas 1 and 2, and comparative formulas 1 and 2 were prepared by means of a Howden B.V. Mondomix pressurized continuous whipping machine. After starting up and adjusting the parameters, the whipping of the formula is initiated.

On the four formulae prepared, at T ₀ , a cream with a "chantilly" appearance, in which the bubbles developed after 24 h, was observed; this in the end gave a care foam suitable for facial care: of the hydrating, freshing, and anti-tacky care product type. Example 2: evaluation example

The density, stability and sensory effect of the invention and comparative formulas prepared in the Example 1 were evaluated.

The densities of the formulas were tested at 20°C using a Gardener pycnometer. The stability tests of the invention formulas and the comparative formulas at 25°C, 40°C, and 45°C for two months were conducted using Binder oven (USA), by leaving the invention and comparative formulas in the oven for 2 months.

The stability tests at 4°C stability for two months were conducted using Zhongke Meiling refrigerator (YC-260L, China), by leaving the invention and comparative formulas in the refrigerator for 2 months.

The transportation and pressure stability tests were conducted by sending the formulas of example 1 via the flight transportation from China to India, for 6 hours.

Finally the sensory effects of the invention and comparative formulas were conducted in India, by applying the formulas obtained from example 1 to the facial skin of 12 women models aging between 18 to 45 years for consecutively 10 days, one time per day. Scores of preference were given by the models by evaluating the hydrating, freshness, and reduction of tack after the application of the formulas:

5: excellent;

4: very good; 3: acceptable;

2: not acceptable in hydrating, freshness or a reduction of tack;

1 : poor.

The result of the stability of the invention and comparative formulas were listed below.

Test Invention Invention Comparative Comparative formula 1 formula 2 formula 1 formula 2

Density at 20°C 0.85 0.84 0.98 0.55 Stability test at different 4°C OK OK OK OK temperatures in 2 months

25°C OK OK OK OK

40°C OK OK OK OK

45°C OK OK OK Air bubbles grew bigger and break, the volume of the formula decreased

Transportation and pressure OK OK Air bubbles Air bubbles stability test disappeared disappeared

Sensory effect 5 5 2 4

It is observed from the results above, that all formulas have low density, while comparative formula 1 does not possess an acceptable sensory, comparing to the invention formulas 1 and 2.

In terms of stabilities over the time, temperature and transportation and pressure, the invention formulas 1 and 2 show improved and excellent stabilities under varied situations, whereas the comparative formulas 1 and 2 are not stable under high temperature, and/or under transportation and pressure.

In conclusion, the invention formulas, having a low density texture, possess an improved stability over the time, temperature and transportation and pressure conditions, and meanwhile maintain an excellent sensory, especially favored by the consumers in the area where the weather is generally warm and the humidity is relative high.