WO2021132044A1

WO2021132044A1 - Cosmetic composition in the form of w/o emulsion comprising spherical hydrophobic silica aerogel and ester oil

Info

Publication number: WO2021132044A1
Application number: PCT/JP2020/047306
Authority: WO
Inventors: Makoto Kawamoto; Kazunori Ogami
Original assignee: L'oreal
Priority date: 2019-12-24
Filing date: 2020-12-11
Publication date: 2021-07-01
Also published as: JP2021102558A; KR20220104009A; JP7536444B2; CN115175656A

Abstract

The present invention relates to a cosmetic composition in the form of a water-in-oil emulsion comprising at least one spherical hydrophobic silica aerogel and at least one ester oil selected from liquid esters of saturated or unsaturated, linear or branched C1-C26 aliphatic monoacid or polyacids and of saturated or unsaturated, linear or branched C1-C26 aliphatic monoalcohol or polyalcohol. The cosmetic composition is stable for a long period of time even if the spherical hydrophobic silica aerogel is comprised in the composition in a large amount.

Description

DESCRIPTION

TITLE OF INVENTION

COSMETIC COMPOSITION IN THE FORM OF W/O EMULSION COMPRISING SPHERICAL HYDROPHOBIC SILICA AEROGEL AND ESTER OIL

TECHNICAL FIELD

The present invention relates to a cosmetic composition in the form of a water-in-oil emulsion comprising at least one spherical hydrophobic silica aerogel and at least one ester oil selected from liquid esters of saturated or unsaturated, linear or branched C1-C26 aliphatic monoacid or polyacids and of saturated or unsaturated, linear or branched C1-C26 aliphatic monoalcohol or polyalcohol, which is stable for a long period of time even if the spherical hydrophobic silica aerogel is comprised in the composition in a large amount.

BACKGROUND ART

Long lasting properties are one of the most important factors for cosmetic compositions, in particular foundations. In order to achieve the long lasting properties, film forming agents such as an MQ resin are used in combination with a specific combination of fillers.

However, most of the fillers used in cosmetic compositions are synthetic organic polymers which are categorized as micro-plastics such as PMMA, Nylon, and Polyurethane. Due to a risk of inducing environmental damage caused by the micro-plastics, there is need to replace the synthetic organic polymers with more eco-friendly fillers derived from natural sources, such as silica.

Therefore, silica silylate aerogel particles such as VM-2270 Aerogel Fine Particles sold by Dow Coming are currently used in cosmetic compositions. These particles can absorb a large amount of sebum and are appropriate for being used in foundations. However, these particles do not have a determined shape. Due to this random shape, if these particles are comprised in a cosmetic composition in a large amount, the texture becomes quite bad.

Spherical silica silylate aerogel particles have recently been developed, and these particles are suggested for imparting matting effects and good smoothness to a cosmetic composition whiling maintaining a high oil absorbance (JP-A-2014-088307, JP-A-2014-218433, and JP-A-2018-177620). However, there is a disadvantage that if the spherical silica silylate aerogel particles are used in a cosmetic composition in a large amount, the composition becomes unstable.

Accordingly, there is a need to provide a cosmetic composition comprising spherical aerogel particles such as spherical silica silylate aerogel particles, which can achieve a long-lasting stability.

DISCLOSURE OF INVENTION

An objective of the present invention is to provide a cosmetic composition comprising spherical hydrophobic silica aerogel, which is stable for a long period of time.

The above objective can be achieved by a cosmetic composition in the form of a W/O emulsion, comprising at least one spherical hydrophobic silica aerogel and at least one ester oil selected from liquid esters of saturated or unsaturated, linear or branched C1-C26 aliphatic monoacid or polyacids and of saturated or unsaturated, linear or branched C1-C26 aliphatic monoalcohol or polyalcohol.

The spherical hydrophobic silica aerogel may be a spherical hydrophobic aerogel of silica silylate.

The spherical hydrophobic silica aerogel may have an average circularity determined by an image analysis method of 0.8 or more, and preferably 0.82 or more, and of less than 1, preferably 0.99 or less, more preferably 0.98 or less, even more preferably 0.97 or less, still even more preferably 0.96 or less, and most preferably 0.95 or less.

The spherical hydrophobic silica aerogel may have an oil-absorbing capacity, measured at the wet point, of 2 ml/g or more, preferably 3 ml/g or more, more preferably 4 ml/g or more, and most preferably from 5 ml/g or more, and of 12 ml/g or less, preferably 11 ml/g or less, more preferably 10 ml/g or less, and most preferably 8 ml/g or less.

The spherical hydrophobic silica gel may have a specific surface area determined by BET method of 200 m²/g or more, preferably 400 m²/g or more, and more preferably 500 m²/g or more, and of 1,200 m²/g or less, preferably 1,000 m²/g or less, and more preferably 800 m²/g or less.

The spherical hydrophobic silica gel may have a pore volume determined by BJH method of 1 ml/g or more, preferably 2 ml/g or more, and more preferably 3 ml/g or more, and of 10 ml/g or less, preferably 8 ml/g or less, and more preferably 7 ml/g or less.

The spherical hydrophobic silica gel may have a peak pore radius determined by BJH method of 5 nm or more, preferably 10 nm or more, and more preferably 12 nm or more, and of 50 nm or less, preferably 30 nm or less, and more preferably 25 nm or less.

The spherical hydrophobic silica gel may have an average particle size of 0.5 pm or more, preferably from 1 pm or more, and more preferably from 2 pm or more, and of 30 pm or less, preferably 20 pm or less, and more preferably 15 pm or less.

The spherical hydrophobic silica aerogel may be present in an amount of 0.05% by weight or more, preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and most probably 0.5% by weight or more, and of 15% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less, and most preferably 2% by weight or less, relative to the total weight of the composition.

The ester oil may be a liquid ester of saturated and linear C5-C15 aliphatic diacid and of saturated and branched C2-C5 aliphatic monoalcohol, and preferably diisopropyl sebacate. The ester oils may be present in an amount of 0.05% by weight or more, preferably 0.1% by weight or more, and more preferably 1% by weight or more, and of 15% by weight or less, preferably 10% by weight or less, and more preferably from 5% by weight or less, relative to the total weight of the composition. The cosmetic composition according to the present invention may be a skin makeup composition, and preferably a foundation.

The present invention also relates to a method of preparing a cosmetic composition in the form of a W/O emulsion, comprising: - mixing oily ingredients comprising at least one spherical hydrophobic silica aerogel and at least one ester oil to prepare an oily phase, wherein the at least one ester oil is selected from liquid esters of saturated or unsaturated, linear or branched C1-C26 aliphatic monoacid or polyacids and of saturated or unsaturated, linear or branched C1-C26 aliphatic monoalcohol or polyalcohol; - preparing a water phase; and

- adding or pouring the water phase into the oily phase while stirring the oily phase.

The present invention also relates to a cosmetic process for a keratin substance such as skin, comprising applying the cosmetic composition according to the present invention to the keratin substance.

BEST MODE FOR CARRYING OUT THE INVENTION

After diligent research, the inventors have found that by combining a spherical hydrophobic silica aerogel and an ester oil selected from liquid esters of saturated or unsaturated, linear or branched C1-C26 aliphatic monoacid or polyacids and of saturated or unsaturated, linear or branched C1-C26 aliphatic monoalcohol or polyalcohol, it is possible to improve the stability of a composition in the form of a W/O emulsion even if the spherical hydrophobic silica aerogel exists in a cosmetic composition in a large amount.

Thus, one aspect of the present invention is a cosmetic composition in the form of a W/O emulsion, comprising at least one spherical hydrophobic silica aerogel and at least one ester oil selected from liquid esters of saturated or unsaturated, linear or branched C1-C26 aliphatic monoacid or polyacids and of saturated or unsaturated, linear or branched C1-C26 aliphatic monoalcohol or polyalcohol.

Hereinafter, the composition according to the present invention will be explained in a more detailed manner. [Spherical Hydrophobic Silica Aerogel]

The composition according to the present invention comprises at least one spherical hydrophobic silica aerogel. Aerogels are materials with high porosity. Herein, silica aerogels refer to a solid silica with a porous structure generally obtained by replacing medium included in wet silica gels with air by drying them while a solid network structure of the silica is maintained. The porosity represents the amount of air contained in an apparent volume of a material by a volume percentage. The spherical hydrophobic silica aerogel of the present invention may have a porosity of 60% or more, preferably 70% or more, and more preferably 80% or more.

The hydrophobic silica aerogel of the present invention is characterized in that the shape of each of the particles is spherical. Due to this spherical shape, the hydrophobic silica aerogel can provide cosmetic compositions with good smoothness. The spherical degree of the hydrophobic silica aerogel may be determined by an average circularity. The spherical hydrophobic silica aerogel of the present invention may have the average circularity of 0.8 or more, and preferably 0.82 or more. The spherical hydrophobic silica aerogel may have the average circularity of less than 1, preferably 0.99 or less, more preferably 0.98 or less, even more preferably 0.97 or less, still even more preferably 0.96 or less, and most preferably 0.95 or less.

The "average circularity" may be determined by an image analysis method. In particular, the "average circularity" may be an arithmetic mean of circularity obtained by image analysis of a scanning electron microscope (SEM) image of no less than 2000 aerogel particles observed at a magnification of 1000 by secondary electron detection using a scanning electron microscope (SEM).

The "circularity" of each aerogel particle is a value determined by the following formula:

C = 4p8 / L² wherein C represents a circularity, S represents an area (projected area) of the aerogel particle in the image, and L represents a length of a periphery (perimeter) of the aerogel particle in the image. When the average circularity approaches 1, the shape of each of the particles becomes more spherical.

In the spherical hydrophobic silica aerogel of the present invention, the term "hydrophobicity" means that the silica aerogel particles is difficult to disperse in water. More specifically, this term means that an aerogel phase and an aqueous phase are completely separated after 1 g of the silica aerogel particles and 100 g of ion-exchange water are added to a bottle, the bottle is agitated or stirred for ten or more seconds, and the bottle is left to stand. Therefore, in one particular embodiment of the present invention, the spherical hydrophobic silica aerogel does not exhibit a water absorption property.

The spherical hydrophobic silica aerogel that may be used according to the present invention is preferably of silylated silica type (INCI name: silica silylate). Most preferably, the spherical hydrophobic silica aerogel may be those described in JP-A-2014-088307,

JP- A-2014-218433, or JP-A-2018-177620.

The hydrophobicity may be obtained by reacting a hydrophobizing agent with a silanol group represented by the following formula existing on the surface of silica: ºSi-OH wherein the symbol "º" represents the remaining three valences of the Si atom, thereby converting the silanol group into a group represented by the following formula: (=Si-0-)(4-n)SiR_n wherein n is an integer of 1 to 3; each R is independently a hydrocarbyl group; and two or more R may be the same or different from each other where n is 2 or more.

The hydrophobizing agent may be a silylating agent. Therefore, according to one preferred embodiment, in the spherical hydrophobic silica aerogel, the silica particles may be modified at the surface by silylation. As examples of the silylating agents, mention may be made of a treating agent having one of the following formulae (1) to (3).

Formula (1):

RnSiX(4-n) wherein n represents an integer of 1 to 3; R represents a hydrocarbyl group; X represents a group (i.e. a leaving group) which can leave a molecule by cleavage of bond with the Si atom in a reaction with a compound having a hydroxyl group; each R may be different where n is 2 or more; and each X may be different where n is 2 or less.

Formula (2):

wherein R¹ represents an alkylene group; R² and R³ independently represent a hydrocarbyl group; and R⁴ and R⁵ independently represent a hydrogen atom or a hydrocarbyl group.

Formula (3):

wherein R⁶ and R⁷ independently represent a hydrocarbyl group; m represents an integer of 3 to 6; each R⁶ may be different when there are two or more R⁶; and each R⁷ may be different when there are two or more R⁷.

In the above formula (1), R is a hydrocarbyl group, preferably a hydrocarbyl group having a carbon number of 1 to 10, more preferably a hydrocarbyl group having a carbon number of 1 to 4, and especially preferably a methyl group.

As examples of the leaving group represented by X, mention may be made of halogen atoms such as chlorine and bromine; alkoxy groups such as methoxy group and ethoxy group; groups represented by -NH-SiR3 (wherein the definition of R is the same as that of R in the formula (1)).

Specific examples of the hydrophobing agent represented by the above formula (1) include: chlorotrimethylsilane, dichlorodimethylsilane, trichloromethylsilane, monomethyltrimethoxysilane, monomethyltriethoxysilane, and hexamethyldisilazane.

Most preferably, chlorotrimethylsilane, dichlorodimethylsilane, trichloromethylsilane, and/or hexamethyldisilazane may be used from the viewpoint of favorable reactivity.

The number of bond of the Si atom with the silanol group on the silica framework varies depending on the number (4-n) of the leaving group X. For example, if n is 2, the following bonding will occur:

(ºSi-0-)2SiR_2.

If n is 3, the following bonding will occur: ºSi-0-SiR_3.

In this manner, the silanol groups may be silylated, and thereby hydrophobization may be carried out.

In the above formula (2), R¹ may be an alkylene group, preferably an alkylene group having a carbon number of 2 to 8, and especially preferably an alkylene group having a carbon number of2 to 3.

In the above formula (2), R² and R³ are independently a hydrocarbyl group, and the same preferable groups as those of R in the formula (1) can be raised. R⁴ represents a hydrogen atom or a hydrocarbyl group, and when it is a hydrocarbyl group, the same preferable groups as those of R in the formula (1 ) can be raised. When a gel of silica is treated with the compound (cyclic silazane) represented by the formula (2), cleavage of Si-N bonds will occur by the reaction with silanol groups, and therefore the following bonding will occur on the surface of the silica framework in the gel:

(ºSi-0-) SiR²R³

In this way, the silanol group may be silylated by the cyclic silazanes of the above formula (2) as well, and thereby hydrophobization may be carried out.

Specific examples of the cyclic silazanes represented by the above formula (3) include hexamethylcyclotrisilazane, and octamethylcyclotetrasilazane.

In the above formula (3), R⁶ and R⁷ are independently a hydrocarbyl group, and the same preferable groups as those of R in the formula (2) can be raised m represents an integer of 3 to 6. When a gel of silica is treated with the compound (cyclic siloxane) represented by the formula (3), the following bonding will occur on the surface of the silica framework in the gel:

(ºSi-0-)₂SiR⁶R⁷ _.

In this way, silanol groups may be silylated by the cyclic siloxanes of the above formula (3) as well, and thereby hydrophobization may be carried out.

Specific examples of the cyclic siloxanes represented by the above formula (3) include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane.

The spherical hydrophobic silica aerogel may be prepared by producing a sol of silica, turning the sol into a gel, aging the gel, washing the aged gel, replacing water in the washed gel with a solvent, treating the gel with a hydrophobizing agent, and dying the hydrophobized silica. The spherical hydrophobic silica aerogel may have a specific surface area determined by BET method of 200 m²/g or more, preferably 400 m²/g or more, and more preferably 500 m²/g or more, and may have a specific surface area determined by BET method of 1,200 m²/g or less, preferably 1,000 m²/g or less, and more preferably 800 m²/g or less. In the present invention, the "specific surface area determined by BET method" means a value determined by: drying a sample for measurement at 200°C for no less than three hours under a reduced pressure of no more than 1 kPa; thereafter measuring an adsorption isotherm of only a nitrogen adsorption side at liquid nitrogen temperature; and analyzing the adsorption isotherm by the BET method. The pressure range used for the analysis is relative pressure of 0.1 to 0.25. The spherical hydrophobic silica aerogel may have a pore volume determined by BJH method of 1 ml/g or more, preferably 2 ml/g or more, and more preferably 3 ml/g or more, and may have a pore volume determined by BJH method of 10 ml/g or less, preferably 8 ml/g or less, and more preferably 7 ml/g or less. The spherical hydrophobic silica aerogel may have a peak pore radius determined by BJH method of 5 nm or more, preferably 10 nm or more, and more preferably 12 nm or more, and may have a peak pore radius determined by BJH method of 50 nm or less, preferably 40 nm or less, and more preferably 30 nm or less.

The "pore volume determined by BJH method" refers to a pore volume which derives from a pore having a pore radius of 1 nm to 100 nm obtained by analyzing, by the BJH method (Barrett, E. R; Joyner, L. G; Halenda, P. R, J. Am. Chem. Soc. 73, 373 (1951)), the adsorption isotherm of the nitrogen adsorption side obtained in the same manner as explained in the above "specific surface area determined by BET method". The "peak pore radius determined by BJT method" refers to a value of a pore radius which gives a peak in a pore distribution curve (volume distribution curve) which is plotted taking on the vertical axis differentiation of the cumulative pore volume by the logarithm of the pore radius obtained by analyzing, by the BJH method, the adsorption isotherm of the nitrogen adsorption side obtained in the same manner as above, and taking the pore radius on the horizontal axis.

The spherical hydrophobic silica aerogel may have an average particle size of 0.5 pm or more, preferably 1 pm or more, and more preferably 2 pm or more, and may have an average particle size by image analysis method of 30 pm or less, preferably 20 pm or less, and more preferably 15 pm or less.

The "average particle size" here can be measured by image analysis method. Specifically, the value of "average particle size" is an arithmetic mean of equivalent circle diameters whch can be obtained by image analysis of a scanning electron microscope (SEM) image of, for example, no less than 2000 aerogel particles observed at a magnification of 1000 by secondary electron detection using a scanning electron microscope (SEM). The "equivalent circle diameter" of each aerogel particle is a diameter of a circle having an area equal to the area (projected area) of the aerogel particle in the image.

Preferably, the spherical hydrophobic silica aerogel may have an oil-absorbing capacity, which can be measured at the wet point, of 2 ml/g or more, preferably 3 ml/g or more, more preferably 4 ml/g or more, and most preferably from 5 ml/g or more, and may have an oil-absorbing capacity, measured at the wet point, of 12 ml/g or less, preferably 11 ml/g or less, more preferably 10 ml/g or less, and most preferably 8 ml/g or less.

The oil-absorbing capacity measured at the wet point, noted Wp, corresponds to the amount of oil that needs to be added to 100 g of particles in order to obtain a homogeneous paste. It can be measured according to the wet point method or the method for determining the oil uptake of a powder described in standard NF T 30-022. The oil uptake can correspond to the amount of oil adsorbed onto the available surface of the powder and/or absorbed by the powder by measuring the wet point, described below.

An amount of m = 2 g of powder is placed on a glass plate, and an oil (such as ester oil, oleric acid, or silicone oil) is then added drop-wise. After addition of 4 to 5 drops of oil to the powder, mixing is performed using a spatula, and addition of oil is continued until a conglomerate of oil and powder has formed. At this point, the oil is added one drop at a time and the mixture is then triturated with the spatula. The addition of oil is stopped when a firm, smooth paste is obtained. This paste must be able to be spread on the glass plate without cracking or forming lumps. The volume Vs (expressed in ml) of oil used is then noted. The oil uptake corresponds to the ratio Vs/m.

Otherwise, an oil-absorbing capacity can be measured in accordance with JIS-K6217-4.

In one preferred embodiments of the present invention, the (a) spherical hydrophobic silica aerogels are those described in JP-A-2014-088307, JP-A-2014-218433, or JP-A-2018- 177620.

The spherical hydrophobic silica aerogels may be present in an amount of 0.05% by weight or more, preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and most probably 0.5% by weight or more, and may be present in an amount of 15% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less, and most preferably 4% by weight or less, relative to the total weight of the composition.

[Ester Oil]

The composition according to the present invention comprises at least one ester oil selected from liquid esters of saturated or unsaturated, linear or branched C1-C26 aliphatic monoacid or polyacids and of saturated or unsaturated, linear or branched C1-C26 aliphatic monoalcohol or polyalcohol.

In the context of present invention, the term "oil" means a fatty substance that is in liquid form at room temperature and atmospheric pressure.

The ester oil of the present invention is liquid esters of saturated or unsaturated, linear or branched C1-C26 aliphatic monoacids or polyacids and of saturated or unsaturated, linear or branched C1-C26 aliphatic monoalcohols or polyalcohols, the total number of carbon atoms of the esters being preferably greater than or equal to 10, and preferably less than or equal to 30.

The carbon number of the C1-C26 aliphatic monoacids or polyacids may be 1, 2, 3, 4, 5, 6, 7, 8,

9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or 26. Also, the carbon number of the C1-C26 aliphatic monoalcohols or polyalcohols may be 1, 2, 3, 4, 5, 6, 7, 8, 9,

10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or 26.

Preferably, the ester oil may be liquid esters of saturated or unsaturated, linear or branched C2-C20 aliphatic polyacids and of saturated or unsaturated, linear or branched C2-C20 aliphatic monoalcohols. More preferably, the ester oil may be liquid esters of saturated and linear C5-C15 aliphatic diacids and of saturated and branched C2-C5 aliphatic monoalcohols.

The ester oil may also be selected from monoesters, diesters, trimesters, tetraesters and polyesters, and mixtures thereof.

The monoesters may have the following formula:

RI-C(=0)-0-R₂ wherein Ri represents a linear or branched alkyl radical of 1 to 40 carbon atoms, preferably of 7 to 19 carbon atoms, optionally comprising one or more ethylenic double bonds, and optionally substituted, and R2 represents a linear or branched alkyl radical of 1 to 40 carbon atoms, preferably of 2 to 30 carbon atoms and even more preferably of 3 to 10 carbon atoms, optionally comprising one or more ethylenic double bonds, and optionally substituted.

The diesters may have the following formula:

R₄-0-C(=0)-R₃-C(=0)-0-R₄ wherein R₃ represents a linear or branched alkylene radical of 1 to 40 carbon atoms, preferably of 7 to 19 carbon atoms, optionally comprising one or more ethylenic double bonds, and optionally substituted and R₄, independently of each other, represents a linear or branched alkyl radical of 1 to 40 carbon atoms, preferably of 3 to 30 carbon atoms and even more preferably of 3 to 10 carbon atoms, optionally comprising one or more ethylenic double bonds, and optionally substituted.

The expression "optionally substituted" is understood to mean that Ri, R2, R₃ and/or R₄ may carry one or more substituents chosen for example from groups comprising one or more heteroatoms chosen from O, N and S, such as amino, amine, alkoxy, hydroxyl.

Preferably, the total number of carbon atoms of Ri + R2 or R₃ + R₄ may be 9 or more, preferably 12 or more, more preferably 16 or more, and most preferably 20 or more.

Among the monoesters of monoacids and of monoalcohols, mention may be made of ethyl palmitate, ethyl hexyl palmitate, isopropyl palmitate, dicaprylyl carbonate, alkyl myristates such as isopropyl myristate or ethyl myristate, isocetyl stearate, 2-ethylhexyl isononanoate, isononyl isononanoate, isodecyl neopentanoate and isostearyl neopentanoate.

Esters of C -C22 dicarboxylic or tricarboxylic acids and of C1-C22 alcohols and esters of monocarboxylic, dicarboxylic or tricarboxylic acids and of non-sugar C -C26 dihydroxy, trihydroxy, tetrahydroxy or pentahydroxy alcohols may also be used.

Mention may especially be made of: diethyl sebacate; isopropyl lauroyl sarcosinate; diisopropyl sebacate; bis(2-ethylhexyl) sebacate; diisopropyl adipate; di-n-propyl adipate; dioctyl adipate; bis(2-ethylhexyl) adipate; diisostearyl adipate; bis(2-ethylhexyl) maleate; triisopropyl citrate; triisocetyl citrate; triisostearyl citrate; glyceryl trilactate; glyceryl trioctanoate; trioctyldodecyl citrate; trioleyl citrate; neopentyl glycol diheptanoate; diethylene glycol diisononanoate.

As the ester oil, one can use sugar esters and diesters of C_6~C₃o and preferably C12-C22 fatty acids. It is recalled that the term "sugar" means oxygen-bearing hydrocarbon-based compounds containing several alcohol functions, with or without aldehyde or ketone functions, and which comprise at least 4 carbon atoms. These sugars may be monosaccharides, oligosaccharides or polysaccharides.

Examples of suitable sugars that may be mentioned include sucrose (or saccharose), glucose, galactose, ribose, fucose, maltose, fructose, mannose, arabinose, xylose and lactose, and derivatives thereof, especially alkyl derivatives, such as methyl derivatives, for instance methylglucose.

The sugar esters of fatty acids may be chosen especially from the group comprising the esters or mixtures of esters of sugars described previously and of linear or branched, saturated or unsaturated C₆-C₃o and preferably C12-C22 fatty acids. If they are unsaturated, these compounds may have one to three conjugated or non-conjugated carbon-carbon double bonds. Use may be made of sucrose, glucose or methylglucose monooleates or dioleates, stearates, behenates, oleopalmitates, linoleates, linolenates and oleostearates.

An example that may be mentioned is the product sold under the name Glucate^® DO by the company Amerchol, which is a methylglucose dioleate.

The esters may be, for example, oleates, laurates, palmitates, myristates, behenates, cocoates, stearates, linoleates, linolenates, caprates and arachidonates, or mixtures thereof such as, especially, oleopalmitate, oleo stearate and palmito stearate mixed esters, as well as pentaerythrityl tetraethyl hexanoate.

As examples of preferable ester oils, mention may be made of, for example, diisopropyl sebacate, diethyl sebacate, and diisopropyl adipate, dioctyl adipate, 2-ethylhexyl hexanoate, ethyl laurate, cetyl octanoate, octyldodecyl octanoate, isodecyl neopentanoate, myristyl propionate, 2-ethylhexyl 2-ethylhexanoate, 2-ethylhexyl octanoate, 2-ethylhexyl caprylate/caprate, methyl palmitate, ethyl palmitate, isopropyl palmitate, dicaprylyl carbonate, isopropyl lauroyl sarcosinate, isononyl isononanoate, ethylhexyl palmitate, isohexyl laurate, hexyl laurate, isocetyl stearate, isopropyl isostearate, isopropyl myristate, isodecyl oleate, glyceryl tri(2-ethylhexanoate), pentaerythrityl tetra(2-ethylhexanoate), 2-ethylhexyl succinate, and mixtures thereof.

The most preferably ester oils may be diisopropyl sebacate.

The ester oils may be present in an amount of 0.05% by weight or more, preferably 0.1% by weight or more, and more preferably 1% by weight or more, and may be present in amount of 15% by weight or less, preferably 10% by weight or less, and more preferably from 5% by weight or less, relative to the total weight of the composition.

[Composition]

The composition according to the present invention is in the form of a W/O emulsion.

The term "W/O emulsion" or "water-in-oil emulsion" means any macro scopically homogeneous composition comprising a continuous fatty or oily phase and aqueous or water phases in the form of droplets dispersed in the said fatty or oily phase.

In one embodiment, the composition in a form of an W/O emulsion of the present invention may be manufactured the following protocol: (1) mixing oily ingredients comprising the spherical hydrophobic silica aerogel and the ester oil to prepare an oily phase, (2) preparing a water phase, and (3) adding or pouring the water phase into the oily phase while stirring the oily phase.

I. Oily phase

The composition of the present invention may comprise at least one additional oil in addition to the ester oil.

In the present invention, the term "oil" means a fatty substance that is in liquid form at room temperature and atmospheric pressure. An oily phase that is suitable for preparing the compositions according to the present invention may comprise oils of plant or animal origin, synthetic oils, hydrocarbon oils, fatty alcohols, and silicone oils, and mixtures thereof.

As examples of plant oils, mention may be made of, for example, hydrocarbon-based oils of plant origin, such as phytostearyl esters such as phytostearyl oleate, phytostearyl isostearate and lauroyl/octyldodecyl/phytostearyl glutamate (Ajinomoto, Eldew PS203), triglycerides formed from fatty acid esters of glycerol, in particular in which the fatty acids may have chain lengths ranging from C4 to C₃₆ and especially from Cis to C₃₆, these oils possibly being linear or branched, and saturated or unsaturated; these oils may especially be heptanoic or octanoic triglycerides, shea oil, alfalfa oil, poppy oil, winter squash oil, millet oil, barley oil, quinoa oil, rye oil, candlenut oil, passionflower oil, shea butter, aloe vera oil, sweet almond oil, peach stone oil, groundnut oil, argan oil, avocado oil, baobab oil, borage oil, broccoli oil, calendula oil, camelina oil, canola oil, carrot oil, safflower oil, flax oil, rapeseed oil, cotton oil, coconut oil (cocos nucifera oil), marrow seed oil, wheatgerm oil, jojoba oil, lily oil, macadamia oil, com oil, meadowfoam oil, St John's Wort oil, monoi oil, hazelnut oil, apricot kernel oil, walnut oil, olive oil, oenothera biennis (evening primrose) oil, palm oil, blackcurrant pip oil, kiwi seed oil, grapeseed oil, pistachio oil, winter squash oil, pumpkin oil, quinoa oil, musk rose oil, sesame oil, soybean oil, sunflower oil, castor oil and watermelon oil, and mixtures thereof, or alternatively caprylic/capric triglycerides, such as those sold by the company Stearineries Dubois or those sold under the names Miglyol 810^®, 812^® and 818^® by the company Dynamit Nobel. Mention may also be made of modified plant oils, for example, activated coconut oil, such as those sold under the names Scalpro or Acnaed by the company Biotropics.

As examples of animal oils, mention may be made of, for example, squalene and squalane.

As examples of synthetic oils, mention may be made of alkane oils such as isododecane and isohexadecane, ether oils, and artificial triglycerides.

As examples of artificial triglycerides, mention may be made of, for example, capryl caprylyl glycerides, glyceryl trimyristate, glyceryl tripalmitate, glyceryl trilinolenate, glyceryl trilaurate, glyceryl tricaprate, glyceryl tricaprylate, glyceryl tri(caprate/caprylate) and glyceryl tri(caprate/ caprylate/linolenate) .

The hydrocarbon oils may be chosen from:

- linear or branched, optionally cyclic, C6-C16 lower alkanes. Examples that may be mentioned include hexane, undecane, dodecane, tridecane, and isoparaffins, for instance isohexadecane, isododecane and isodecane; and

- linear or branched hydrocarbons containing more than 16 carbon atoms, such as liquid paraffins, liquid petroleum jelly, polydecenes and hydrogenated polyisobutenes such as Parleam^®, and squalane.

As examples of hydrocarbon oils, mention may be made of, for example, linear or branched hydrocarbons such as isohexadecane, isododecane, squalane, mineral oil (e.g., liquid paraffin), paraffin, vaseline or petrolatum, naphthalenes, and the like; hydrogenated polyisobutene, isoeicosane, and decene/butene copolymer; and mixtures thereof.

The term "fatty" in the fatty alcohol means the inclusion of a relatively large number of carbon atoms. Thus, alcohols which have 4 or more, preferably 6 or more, and more preferably 12 or more carbon atoms are encompassed within the scope of fatty alcohols. The fatty alcohol may be saturated or unsaturated. The fatty alcohol may be linear or branched.

The fatty alcohol may have the structure R-OH wherein R is chosen from saturated and unsaturated, linear and branched radicals containing from 4 to 40 carbon atoms, preferably from 6 to 30 carbon atoms, and more preferably from 12 to 20 carbon atoms. In at least one embodiment, R may be chosen from C₁₂-C₂₀ alkyl and C₁₂-C20 alkenyl groups. R may or may not be substituted with at least one hydroxyl group.

As examples of the fatty alcohol, mention may be made of lauryl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, undecylenyl alcohol, myristyl alcohol, octyldodecanol, hexyldecanol, oleyl alcohol, linoleyl alcohol, palmitoleyl alcohol, arachidonyl alcohol, erucyl alcohol, and mixtures thereof.

Thus, the fatty alcohol may be selected from straight or branched, saturated or unsaturated C₆-C₃₀ alcohols, preferably straight or branched, saturated C6-C30 alcohols, and more preferably straight or branched, saturated C₁₂-C₂₀ alcohols.

The term "saturated fatty alcohol" here means an alcohol having a long aliphatic saturated carbon chain. It is preferable that the saturated fatty alcohol be selected from any linear or branched, saturated C₆-C₃₀ fatty alcohols. Among the linear or branched, saturated C6-C30 fatty alcohols, linear or branched, saturated C₁₂-C₂₀ fatty alcohols may preferably be used.

Any linear or branched, saturated C₁₆-C₂₀ fatty alcohols may be more preferably used. Branched C₁₆-C₂₀ fatty alcohols may be even more preferably used.

As examples of saturated fatty alcohols, mention may be made of lauryl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, undecylenyl alcohol, myristyl alcohol, octyldodecanol, hexyldecanol, and mixtures thereof. In one embodiment, cetyl alcohol, stearyl alcohol, octyldodecanol, hexyldecanol, or a mixture thereof (e.g., cetearyl alcohol) as well as behenyl alcohol, can be used as a saturated fatty alcohol.

As examples of silicone oils, mention may be made of, for example, linear organopolysiloxanes such as dimethylpolysiloxane (dimethicone), methylphenylpolysiloxane, methylhydrogenpolysiloxane, and the like; cyclic organopolysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and the like; and mixtures thereof.

The oils other than the ester oil may be present in the composition in a content of 1% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more, and even more preferably 15% by weight or more, and it may be present in the composition in a content of 40% by weight or less, preferably 30% by weight or less, and more preferably 20% by weight or less, relative to the total weight of the composition.

II. Aqueous Phase

The aqueous phase of a composition according to the present invention comprises at least one aqueous medium, i.e., water and optionally a water-soluble solvent.

In the present invention, the term "water-soluble solvent" denotes a compound that is liquid at room temperature and water-miscible (miscibility with water of greater than 50% by weight at 25°C and atmospheric pressure).

The water-soluble solvents that may be used in the composition of the present invention may also be volatile.

Among the water-soluble solvents that may be used in the composition in accordance with the present invention, mention may be made especially of alcohol, for example lower monoalcohols containing from 1 to 5 carbon atoms, such as ethanol and isopropanol, glycols containing from 2 to 8 carbon atoms, such as ethylene glycol, propylene glycol, 1,3 -butylene glycol and dipropylene glycol, C3 and C4 ketones and C2-C4 aldehydes.

According to another embodiment variant, the aqueous phase of a composition according to the present invention may comprise at least one C2-C32 polyol.

For the purposes of the present invention, the term "polyol" should be understood as meaning any organic molecule comprising at least two free hydroxyl groups. Preferably, a polyol in accordance with the present invention is present in liquid form at room temperature.

A polyol that is suitable for use in the present invention may be a compound of linear, branched or cyclic, saturated or unsaturated alkyl type, bearing on the alkyl chain at least two -OH functions, in particular at least three -OH functions and more particularly at least four -OH functions. The polyols advantageously suitable for the formulation of a composition according to the present invention are those exhibiting in particular from 2 to 32 carbon atoms and preferably from 3 to 16 carbon atoms. Advantageously, the polyol may be chosen, for example, from ethylene glycol, pentaerythritol, trimethylolpropane, propylene glycol,

1,3 -propanediol, butylene glycol, isoprene glycol, pentylene glycol, hexylene glycol, glycerol (glycerin), polyglycerols such as glycerol oligomers, for instance diglycerol, and polyethylene glycols, and mixtures thereof. According to one particular embodiment, the composition of the present invention may comprise at least glycerol.

The aqueous phase (water and optionally the water-miscible solvent) may be present in the composition in a content of 5% by weight or more, preferably 10% by weight or more, and more preferably 25% by weight or more, and it may be present in the composition in a content of 50% by weight or less, preferably 45% by weight or less, and more preferably 35% by weight or less, relative to the total weight of the said composition.

[Composite Silica Particles]

The composition according to the present invention may comprise at least one composite silica particle.

In the context of the present invention, the term "composite silica particles" means silica particles within which functional compounds, preferably metal oxides, are included.

Therefore, preferably, the composite silica particles may refer to "metal oxide-including silica particles". Most preferably, the metal oxides are scattered inside the silica particles.

The metal oxides may preferably be chosen from titanium oxide, zinc oxide, iron oxide and zirconium oxide, or mixtures thereof, and more particularly from titanium dioxide (T1O2) and zinc oxide, and mixtures thereof. Particularly preferably, titanium dioxide may be used. The composite silica particles may have an average particle size determined by image analysis method of 0.1 pm or more, preferably 0.5 pm or more, and more preferably 1 pm or more, and may have an average particle size by image analysis method of 50 pm or less, preferably 20 pm or less, and more preferably 12 pm or less.

The "average particle size" can be determined in accordance with the following procedure: Particle sizes of 50 particles are measured using a SEM image and an average value of the particle sizes is calculated.

The composite silica particles may be porous or non-porous, and they may have a low oil-absorbing capacity.

In the composite silica particles, the weight ratio of silica to the functional compounds (preferably metal oxides and most preferably titanium dioxide) may be from 9:1 to 5:5, preferably from 4:1 to 3:2, and more preferably 7:3.

The composite silica particles may be surface-treated to be hydrophobic. For example, the composite silica particle may be surface-treated with alkylsilanes.

Most preferably, CHIFFONSIL-5T sold by JGC Catalysts and Chemicals may be used as the composite silica particles.

The composite silica particles may be present in an amount of 0.01% by weight or more, preferably 0.5% by weight or more, and more preferably 1% by weight or more, relative to the total weight of the composition. The composite silica particles may be present in an amount of 10% by weight or less, preferably 7% by weight or less, and more preferably 5% by weight or less, relative to the total weight of the composition.

[Surfactant]

The composition according to the present invention may comprise at least one surfactant chosen from amphoteric, anionic, cationic, or nonionic surfactants, used alone or as a mixture.

Examples of anionic surfactants usable in the compositions of the invention may include alkyl sulfates, alkyl ether sulfates, alkyl sulfonates, alkyl ether sulfonates, sulfate esters of an alkylphenoxy polyoxyethylene ethanol, alpha-olefin sulfonates, beta alkyloxy alkene sulfonates, alkyl arylsulfonates, alkyl carbonates, succinamates, sulfosuccinates, sarcosinates, octoxynol or nonoxynol phosphates, taurates, fatty taurides, sulfated monoglycerides, fatty acid amino polyoxyethylene sulfates, isethionates, alkyl benzene sulfonic acids, polyoxyethylene alkyl ether sulfuric acids, polyoxyethylene alkyl ether carboxylic acids, and polyoxyethylene alkyl amide ether carboxylic acids, and salts thereof.

Examples of nonionic surfactants usable in the compositions of the invention may include polyethoxylated fatty alcohols or polyglycerolated fatty alcohols, such as the adducts of ethylene oxide with lauryl alcohol, especially those containing from 9 to 50 oxyethylene units (Laureth-9 to Laureth-50 as the INCI names), in particular Laureth-9; esters of polyols and of a fatty acid possessing a saturated or unsaturated chain comprising, for example, from 8 to 24 carbon atoms, and their oxyalkylenated derivatives, that is to say comprising oxyethylene and/or oxypropylene units, such as esters of glycerol and of a C8-C24 fatty acid, and their oxyalkylenated derivatives, in particular polyoxyethylenated glyceryl stearate (mono-, di- and/or tristearate), for examples PEG-30 dipolyhydroxystearate and PEG-20 glyceryl triisostearate; esters of sugar and of a C8-C24 fatty acid and their oxyalkylenated derivatives, such as polyethoxylated sorbitol esters of C8-C24 fatty acids, in particular Polysorbate 80, such as the product marketed under the name "TWEEN 80" by Croda; ethers of a sugar and of C8-C24 fatty alcohols, such as caprylyl/capryl glucoside; polyoxyethylene alkyl ethers; polyoxyethylene oxypropylene alkyl ethers; fatty acid alkanol amides; alkyl amine oxides; alkyl polyglycosides and silicone surfactants, such as polydimethylsiloxane containing oxyethylene groups and/or oxypropylene groups, for example, PEG- 10 dimethicone, bis-PEG/PPG- 14/14 dimethicone, bis-PEG/PPG-20/20 dimethicone, and PEG/PPG-20/6 dimethicone.

Examples of amphoteric surfactants usable in the compositions of the invention may include alkanoyl amide propyl -N,N-dimethyl glycine betaines, alkanoyl amide propyl-N,N-dimethyl-2-hydroxypropyl sulfobetaines, alkyl-N,N-dimethyl glycine betaines, alkanoyl amide propyl-N,N-dimethyl-propyl sulfobetaines, lauryl-N,N-dimethyl-2-hydroxypropyl sulfobetaines, and salts thereof.

Examples of cationic surfactants usable in the compositions of the invention may include C8-C24 long-chain di-alkyl dimethyl ammonium salts, long-chain mono-alkyl monobenzyl dimethyl ammonium salts and long-chain mono-alkyl trimethyl ammonium salts, all of which may have amide or ester linkages therein, and the counter ions are preferably halogen atoms such as chlorine and bromine atoms, sulfates, and alkyl group-containing sulfate residues such as methyl- and ethyl- sulfuric acid, and salts thereof. Cationic surfactants of amine type include long-chain di-alkyl monomethyl amine salts with a long-chain C8-C24 alkyl group which may have an amide or ester linkage therein, preferably in the form of hydrochlorides, sulfates or phosphates, and salts thereof.

The surfactants may be present in the composition in a content of 0.5% by weight or more, preferably 1% by weight or more, and more preferably 1.5% by weight or more, and it may be present in the composition in a content of 15% by weight or less, preferably from 10% by weight or less, and more preferably 5% by weight or less, relative to the total weight of the composition.

[UV filter]

The composition according to the present invention may comprise at least one UV filter.

The UV filter may be solid or liquid, preferably liquid. The terms "solid" and "liquid" mean solid and liquid, respectively, at 25°C under 1 atm. The UV filter may be made from at least one organic or inorganic material, preferably at least one organic material. Thus, the UV filter is preferably an organic UV filter.

The organic UV filter may be selected from the group consisting of anthranilic derivatives; dibenzoylmethane derivatives; cinnamic derivatives; salicylic derivatives such as homosalate (homomenthyl salicylate) and ethylhexyl salicylate; camphor derivatives; benzophenone derivatives; b,b-diphenylacrylate derivatives; triazine derivatives; benzotriazole derivatives; benzalmalonate derivatives; benzimidazole derivatives; imidazoline derivatives; bis-benzoazolyl derivatives; p-aminobenzoic acid (PABA) and derivatives thereof; benzoxazole derivatives; screening polymers and screening silicones; dimers derived from a-alkylstyrene; 4,4-diarylbutadienes; octocrylene and derivatives thereof, guaiazulene and derivatives thereof, rutin and derivatives thereof, flavonoids, biflavonoids, oryzanol and derivatives thereof, quinic acid and derivatives thereof, phenols, retinol, cysteine, aromatic amino acids, peptides having an aromatic amino acid residue, and mixtures thereof.

The UV filters may be present in the composition in a content of 1% by weight or more, preferably 3% by weight or more, and more preferably 5% by weight or more, and it may be present in the composition in a content of 15% by weight or less, preferably 10% by weight or less, and more preferably 8% by weight or less, relative to the total weight of the composition.

[Colorant or Pigment]

The composition according to the present invention may comprise at least one colorant or pigment to impart a desired color or effect.

Examples of the colorants or pigments may include inorganic pigments, organic pigments, and/or lakes.

As examples of the inorganic pigments, mention may be made of metal oxides and metal hydroxides such as magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxides, aluminum oxide, aluminum hydroxide, iron oxides (a-FeaCfi, g-I¾03, FesCfi, FeO), red iron oxide, yellow iron oxide, black iron oxide, iron hydroxides, titanium dioxide, titaniumlower oxides, zirconium oxides, chromium oxides, chromium hydroxides, manganese oxides, cobalt oxides, cerium oxides, nickel oxides and zinc oxides and composite oxides and composite hydroxides such as iron titanate, cobalt titanate and cobalt aluminate. Suitable inorganic pigments also include non-metal oxides such as alumina and silica, ultramarine blue (i.e., sodium aluminum silicate containing sulfur), Prussian blue, manganese violet, bismuth oxychloride, talc, mica, sericite, magnesium carbonate, calcium carbonate, magnesium silicate, aluminum magnesium silicate, silica, titanated mica, iron oxide titanated mica, bismuth oxychloride, and the like.

As examples of the organic pigments, mention may be made of carbon black, carmine, phthalocyanine blue and green pigment, diarylide yellow and orange pigments, and azo-type red and yellow pigments such as toluidine red, litho red, naphthol red and brown pigments, and combinations thereof.

"Lakes" generally refer to a colorant prepared from a water-soluble organic dye, (e.g., D&C or FD&C) which has been precipitated onto an insoluble reactive or adsorptive substrate or diluent. The term "D&C" as used herein means drug and cosmetic colorants that are approved for use in drugs and cosmetics by the FDA. The term "FD&C" as used herein means food, drug, and cosmetic colorants which are approved for use in foods, drugs, and cosmetics by the FDA. Substrates suitable for forming lakes include, without limitation, mica, bismuth oxychloride, sericite, alumina, aluminum, copper, bronze, silver, calcium, zirconium, barium, and strontium, titanated mica, fumed silica, spherical silica, polymethylmethacrylate (PMMA), micronized teflon, boron nitride, acrylate copolymers, aluminum silicate, aluminum starch octenylsuccinate, bentonite, calcium silicate, cellulose, chalk, corn starch, diatomaceous earth, fuller's earth, glyceryl starch, hectorite, hydrated silica, kaolin, magnesium aluminum silicate, magnesium trisilicate, maltodextrin, montmorillonite, microcrystalline cellulose, rice starch, silica, talc, mica, titanium dioxide, zinc laurate, zinc myristate, zinc rosinate, alumina, attapulgite, calcium carbonate, calcium silicate, dextran, nylon, silica silylate, silk powder, sericite, soy flour, tin oxide, titanium hydroxide, trimagnesium phosphate, walnut shell powder, and mixtures thereof.

The colorants or pigments may be surface treated, for example, to make them more hydrophobic or more dispersible in a vehicle. Surface treatment compounds may include a hydrophobic portion which is selected from, for example, alkyl, aryl, allyl, vinyl, alkyl-aryl, aryl-alkyl, organosilicone, di-organosilicone, dimethicones, methicones, polyurethanes, silicone-polyurethanes, and fluoro- or perfluoro-derivatives thereof. Other hydrophobic modifiers may include lauroyl lysine, isopropyl titanium triisostearate (ITT), ITT and dimethicone (ITT/dimethicone) cross-polymers, ITT and amino acid,

ITT/triethoxycaprylylsilane crosspolymer, waxes (e.g., camauba), fatty acids (e.g., stearates), HDI/trimethylol hexylactone crosspolymer, PEG-8 methyl ether triethoxysilane, aloe, jojoba ester, lecithin, perfluoroalcohol phosphate, and Magnesium Myristate (MM).

Interference or pearl pigments may be included in the composition according to the present invention. The interference or pearl pigments typically may be formed of micas layered with about 50 to 300 nm films of TiCfr, Fe2C>3, or CT2O3 or the like. The interference or pearl pigments may include white nacreous materials, such as mica covered with titanium oxide or covered with bismuth oxychloride; and colored nacreous materials, such as titanium mica with iron oxides, titanium mica with ferric blue or chromium oxide, titanium mica with an organic pigment of the aforementioned type.

Preferably, the composition according to the present invention may comprise "titanium dioxide (and) alumina (and) isopropyl titanium triisostearate", "iron oxides (and) isopropyl titanium triisostearate", and/or "titanium dioxide (and) aluminum hydroxide (and) dimethicone (and) hydrogen dimethicone".

The colorants or pigments may be present in the composition in a content of 1% by weight or more, preferably 5% by weight or more, and more preferably 10% by weight or more, and they may be present in the composition in a content of 25% by weight or less, preferably less than 20% by weight, and more preferably 15% by weight or less, relative to the total weight of the composition.

[Additives]

The composition according to the present invention may also comprise any other optional additive(s) usually used in the field of cosmetics, chosen, for example, from fillers such as magnesium sulfate, dyes, resins, dispersants, antioxidants, preserving agents such as phenoxyethanol, fragrances, neutralizers, pH adjusting agents, antiseptics, other cosmetic active agents, such as vitamins, moisturizers, emollients or collagen-protecting agents, and mixtures thereof.

Especially, the composition according to the present invention may comprise film-forming agents such as film-forming silicone resins, for example trimethylsiloxysilicate. Also, the composition according to the present invention may comprise thickners such as hydrophilic thickeners, for example hectorite modified with a C 10 to C22 fatty acid ammonium chloride, in particular hectorite modified with distearyldimethylammonium chloride (disteardimonium hectorite).

Furthermore, in addition to the spherical hydrophobic silica aerogel, the composition according to the present invention may comprise additional oil-absorbable particles. As examples of the oil-absorbable particles, mention may be made of cellulose, silica, silicate, perlite, boron nitride, magnesium carbonate, magnesium hydroxide, hydrophobic silica such as silica silicate, kaolin, talc, polyamide (in particular Nylon-6) powders, powders of acrylic polymers, especially of polymethyl methacrylate, of polymethyl methacrylate/ethylene glycol dimethacrylate, of polyallyl methacrylate/ethylene glycol dimethacrylate, or of ethylene glycol dimethacrylate/lauryl methacrylate copolymer, silicones, and mixtures thereof.

These additives and their concentrations, should be such that they do not modify the property which is desired for the composition of the present invention.

[Process and Use]

The composition according to the present invention is intended to be used as a cosmetic composition. Therefore, the cosmetic composition according to the present invention may be intended for application onto keratin substances, for example the skin, scalp, hair, mucosa such as lips, and nails, in particular the skin, for instance that of the face.

The composition according to the present invention may be used as a skin cosmetic composition, preferable a skin makeup composition, and more preferably a foundation.

The composition according to the present invention may be used for a cosmetic process of making up keratin substances, for example the skin, scalp, hair, mucosa such as lips, and nails, in particular the skin for instance that of the face, comprising the composition according to the present invention to the keratin substances.

The present invention also relates to the use of at least one ester oil in a cosmetic composition in the form of a W/O emulsion comprising at least one spherical hydrophobic silica aerogel, in order to stabilize the composition.

Another aspect of the present invention is an ester oil for use in increasing the stability of a cosmetic composition in the form of a W/O emulsion comprising at least one spherical hydrophobic silica aerogel.

EXAMPLES .

The present invention will be described in a more detailed manner by way of examples. However, these examples should not be construed as limiting the scope of the present invention.

Examples 1 to 4 and Comparative Example 1

Preparation method of inventive and comparative foundation compositions

The ingredients of phase (Al) described in Table 1 were completely mixed at 45°C. The ingredient of phase (A2) was added to the phase (Al) and they were completely dissolved. The ingredient of phase (A3) was added and mixed with a Moritz homogenizer at 3,500 rpm for 5 min at 45°C. The ingredients of phases (B), (Cl), and (C2) were added and were mixed at 3,500 rpm for 10 min. A mixture of the ingredients of phase (D) were added and mixed for 10 min at 3,500 rpm at 45°C. The resultant foundation compositions were cooled down to 25°C. Finally, the ingredient of phase (E) was added and mixed at 3,000 rpm for 5 min so as to obtain W/O emulsion-type foundation compositions.

The spherical silica silylate aerogel in phase (C2) had 10 pm of the average primary particle size, 0.88 of an average circularity, 592 m²/g of BET specific surface area, 4.0 ml/g of a pore volume determined by BJH method, 6.8 mL/g of an oil absorption capacity measured with JIS-K6217-4, and 20 nm of a peak pore radius determined by BJE1 method.

Table 1

In Table 1, all ingredients are based on “% by weight” as active raw materials. Evaluation

[Stability]

Each of the inventive and comparative W/O emulsion-type foundation compositions was left to stand at 45 °C. The stability was evaluated from a change in appearance, in particular a separation between aqueous and oily phases. The criteria was as follows: "Very Good" means that the emulsion was stable for two months, "Good" means that the emulsion was stable for one month, but the oily phase was slightly separated after two months, "Fair" means that the emulsion was stable for one week, but the oily phase was slightly separated after one month, and "Poor" means that the aqueous and oily phases were separated after one day.

[Flexibility of Film]

Each of the inventive and comparative W/O emulsion-type foundation compositions was homogenously applied on artificial skin (artificial leather sold by Idemitsu Techno Fine Ltd., Model name: SUPPLALE®) at a rate of 1.5 mg/cm². The skin was left to stand for thirty minutes and films derived from the foundation compositions were formed on the artificial skin. The skin was forced to shrink and expand by hand for 10 seconds. This "shrinking and expanding" process was performed for ten seconds three times, and it was evaluated whether cracks are produced by observation. The criteria was as follows: "Very Good" means that no cracks were produced, "Good" means that a few thin cracks were produced, and "Poor" means that a lot of cracks were produced.

The results are shown in Table 1.

As shown in Table 1 above, only combinations of the spherical hydrophobic silica aerogel and the ester oil of the present invention had not only high stability but also high flexibility. On the other hand, when the ester oil was not used, the stability was very low and a lot of cracks were produced. Therefore, it was demonstrated that the ester oil of the present invention can improve the stability of the composition comprising the spherical hydrophobic silica aerogel in a large amount.

Claims

1. A cosmetic composition in the form of a W/O emulsion, comprising at least one spherical hydrophobic silica aerogel and at least one ester oil selected from liquid esters of saturated or unsaturated, linear or branched C1-C26 aliphatic monoacid or polyacids and of saturated or unsaturated, linear or branched C1-C26 aliphatic monoalcohol or polyalcohol.

2. The cosmetic composition according to Claim 1, wherein the spherical hydrophobic silica aerogel is a spherical hydrophobic aerogel of silica silylate.

3. The cosmetic composition according to Claim 1 or 2, wherein the spherical hydrophobic silica aerogel has an average circularity determined by an image analysis method of 0.8 or more, and preferably 0.82 or more, and of less than 1, preferably 0.99 or less, more preferably 0.98 or less, even more preferably 0.97 or less, still even more preferably 0.96 or less, and most preferably 0.95 or less.

4. The cosmetic composition according to any one of Claims 1 to 3, wherein the spherical hydrophobic silica aerogel has an oil-absorbing capacity, measured at the wet point, of 2 ml/g or more, preferably 3 ml/g or more, more preferably 4 ml/g or more, and most preferably from 5 ml/g or more, and of 12 ml/g or less, preferably 11 ml/g or less, more preferably 10 ml/g or less, and most preferably 8 ml/g or less.

5. The cosmetic composition according to any one of Claims 1 to 4, wherein the spherical hydrophobic silica gel has a specific surface area determined by BET method of 200 m²/g or more, preferably 400 m²/g or more, and more preferably 500 m²/g or more, and of 1,200 m²/g or less, preferably 1,000 m²/g or less, and more preferably 800 m²/g or less.

6. The cosmetic composition according to any one of Claims 1 to 5, wherein the spherical hydrophobic silica gel has a pore volume determined by B JH method of 1 ml/g or more, preferably 2 ml/g or more, and more preferably 3 ml/g or more, and of 10 ml/g or less, preferably 8 ml/g or less, and more preferably 7 ml/g or less.

7. The cosmetic composition according to any one of Claims 1 to 6, wherein the spherical hydrophobic silica gel has a peak pore radius determined by B JH method of 5 nm or more, preferably 10 nm or more, and more preferably 12 nm or more, and of 50 nm or less, preferably 30 nm or less, and more preferably 25 nm or less.

8. The cosmetic composition according to any one of Claims 1 to 7, wherein the spherical hydrophobic silica gel has an average particle size of 0.5 pm or more, preferably from 1 pm or more, and more preferably from 2 pm or more, and of 30 pm or less, preferably 20 pm or less, and more preferably 15 pm or less.

9. The cosmetic composition according to any one of Claims 1 to 8, wherein the spherical hydrophobic silica aerogel is present in an amount of 0.05% by weight or more, preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and most probably 0.5% by Weight or more, and of 15% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less, and most preferably 2% by weight or less, relative to the total weight of the composition.

10. The cosmetic composition according to any one of Claims 1 to 9, wherein the ester oil is a liquid ester of saturated and linear C5-C15 aliphatic diacid and of saturated and branched C2-C5 aliphatic monoalcohol, and preferably diisopropyl sebacate.

11. The cosmetic composition according to any one of Claims 1 to 10, wherein the ester oils is present in an amount of 0.05% by weight or more, preferably 0.1% by weight or more, and more preferably 1% by weight or more, and of 15% by weight or less, preferably 10% by weight or less, and more preferably from 5% by weight or less, relative to the total weight of the composition.

12. The cosmetic composition according to any one of Claims 1 to 11, wherein the cosmetic composition is a skin makeup composition, and preferably a foundation.

13. A method of preparing a cosmetic composition in the form of a W/O emulsion, comprising:

- mixing oily ingredients comprising at least one spherical hydrophobic silica aerogel and at least one ester oil to prepare an oily phase, wherein the at least one ester oil is selected from liquid esters of saturated or unsaturated, linear or branched C1-C26 aliphatic monoacid or polyacids and of saturated or unsaturated, linear or branched C1-C26 aliphatic monoalcohol or polyalcohol;

- preparing a water phase; and

14. A cosmetic process for a keratin substance such as skin, comprising applying the cosmetic composition according to any one of Claims 1 to 12 to the keratin substance.