WO2018113985A1

WO2018113985A1 - Cosmetic balm with ester and alkylpolyglycoside surfactants

Info

Publication number: WO2018113985A1
Application number: PCT/EP2016/082457
Authority: WO
Inventors: Hongjuan WANG
Original assignee: L'oreal
Priority date: 2016-12-22
Filing date: 2016-12-22
Publication date: 2018-06-28
Also published as: CN110430864A

Abstract

This invention relates to a solid composition in form of oil-in-water emulsion, comprising: (i) at least one structuring agent with a melting point of greater than or equal to 50º C, (ii) at least one structuring agent different from (i), having a melting point of less than or equal to 45°C, (iii) at least one surfactant of alkylpolyglycoside type; and (iv) at least one non-ionic surfactant of ester type, comprising a mixture of at least one monounsaturated ester and at least one polyglyceryl diester.

Description

COSMETIC BALM WITH ESTER AND ALKYLPOLYGLYCOSIDE SURFACTANTS

The present invention relates to solid cosmetic compositions that are useful for personal skin care.

The development of formulations dedicated to caring for and/or making up the skin and/or lips, is permanent. Said formulations have to show satisfactory properties in terms of application, such as easy usage, and also in terms of sensory, such as hydration and/or moisturizing feeling after application.

The skin is the protective barrier for the human body. It protects the interior of the body from physical injury (such as trauma) and biological injury (such as bacteria, viruses or fungi). The skin of the human body comprises the dermis and the epidermis. The epidermis is the top most layer of the skin, and its superficial layer is called the stratum corneum.

Moisturization is provided to the skin by the water in the deep-lying layers and by perspiration. Cutaneous moisturization disorders, and especially skin dryness, are often observed with age and/or changes in climate. However, such conditions may also be manifested in young individuals.

A wide variety of cosmetic compositions have been used to care for the skin, in particular to provide moisturizing or hydration to the skin. These compositions typically contain lipophilic moisturizing agents that inhibit water loss via occlusion. These compositions can additionally comprise other skin benefit agents such as vitamins and humectants. Addition of these ingredients can increase the moisturization of the skin. For example, efforts have been made to formulate compositions in the form of creams or solid emulsions. Thanks to the thick texture, it is possible to provide to the skin moisturizing feeling via occlusion. The solid emulsions are usually in the form of water-in-oil emulsion.

However, these types of products are still not satisfying.

Consumers feel an unappealing greasy feeling after application, and moreover, the product in the form of solid emulsion is sometimes found difficult to pick up by fingers. Moreover, due to the thick texture of solid emulsions of the products, it is not easy to apply on the skin evenly.

There is thus still a need to formulate a composition for caring for the skin, which has good cosmetic properties, in particular moisturizing and/or hydration of the skin without greasy feelings. There is a need to formulate a composition as described above, with a desired thick or even solid texture, and easy to apply. In particular, the composition as described above is easy to pick up by fingers.

Besides, the composition is expected to be easily spread on the skin during application.

It is therefore desirable to provide skin care compositions that present excellent application and sensory characteristics.

The Applicant has now discovered that it is possible to formulate such compositions having the desired properties as described above.

Specifically, the Applicant has discovered that it is possible to formulate compositions for caring for and/or making up of keratin materials, particularly solid compositions, which are easy to pick up, which melt while shearing, and which confer a fresh feeling after application onto skin.

Accordingly, the present invention relates to a solid composition in form of an oil-in- water emulsion, comprising:

(i) at least one structuring agent with a melting point of greater than or equal to 50⁵C,

(ii) at least one structuring agent, different from the structuring agent (i), having a melting point of less than or equal to 45°C,

(iii) at least one surfactant of alkylpolyglycoside type; and

(iv) at least one non-ionic surfactant of ester type, comprising a mixture of at least one monounsaturated ester and at least one polyglyceryl diester.

The solid composition of the invention is in form of an oil-in-water emulsion. Thus, said solid composition comprises a continuous aqueous phase and a dispersed fatty phase.

The term "solid" characterizes the state of the composition at room temperature (25°C) and at atmospheric pressure (760 mmHg). In particular, the term "solid composition" is understood to mean a composition having a hardness of greater than 120g.

The measurement of the hardness is carried out according to the following protocol:

The composition of the invention is stored at 20°C for 24 hours before measuring the hardness.

The hardness can be measured at 20°C by pressing the composition of the present invention using a cylinder with a diameter of 20 mm, with the following parameter:

the trigger force of the cylinder is 5g,

the rate of descent is 2 mm/s, the descent depth is 10 mm below the surface of the composition of the present invention.

The hardness of the samples of compositions of the invention, expressed in g, is measured using a Texture analyser sold by Lotun science co.Ltd.

The measurement is repeated three times and then averaged.

For a measurement at a different temperature, the stick is stored at this new temperature for 24 hours before the measurement.

According to this method, the hardness at 20°C of the composition according to the invention is greater than 100g, preferably greater than 120g.

According to this method, the hardness at 20°C of the composition according to the invention is preferably less than 350g, in particular less than 300g, preferably less than 250g.

Preferably, the composition according to the invention has a hardness of between 100g and 350g, or even from 120g to 300g.

Preferably, the composition according to the invention has a hardness of between 120g and 250g.

The composition of the present invention is easy to melt while shearing. Consequently, the composition of the present invention is easy to apply evenly on the skin, without long term massaging by fingers.

Preferably, the property is measured by yield stress of the present invention.

According to an embodiment, the yield stress is measured using Physica MCR 301 sold by the company Anton Paar, under a shear rate from 0.1 to 40 s^"1.

Preferably, the yield stress, expressed in Pa, of the composition according to the invention is between 200 Pa and 400 Pa, preferably between 200 Pa and 350 Pa. The solid composition of the invention presents an improved usage or application and sensory as compared to skin care compositions currently on the market: it is very easy to pick up and spread, while bringing a fresh and moisturizing feeling after application. Other subjects and characteristics, aspects and advantages of the invention will emerge even more clearly on reading the description and the examples that follows.

In that which follows and unless otherwise indicated, the limits of a range of values are included within this range, in particular in the expressions "of between" and "ranging from ... to

Moreover, the expression "at least one" used in the present description is equivalent to the expression "one or more". Throughout the instant application, the term "comprising" is to be interpreted as encompassing all specifically mentioned features as well optional, additional, unspecified ones. As used herein, the use of the term "comprising" also discloses the embodiment wherein no features other than the specifically mentioned features are present (i.e. "consisting of").

Aqueous phase

The solid composition of the invention comprises a continuous aqueous phase. Said aqueous phase is preferably present in an amount ranging from 10% to 99% by weight, more preferably from 20% to 90% by weight, and even more preferably from 50% to 85% by weight of the total weight of the composition.

Water is preferably present in the composition of the present invention in an amount ranging from 1 % to 80% by weight, preferably from 5% to 77% by weight, more preferably from 10% to 75% by weight, relative to the total weight of the composition.

The continuous aqueous phase may comprise water, at least one organic solvent miscible with water or mixtures thereof.

Preferably, the continuous hydrophilic phase comprises at least one organic solvent miscible with water (at room temperature 25°C) such as for example monoalcohols having from 2 to 6 carbon atoms such as ethanol, isopropanol; polyols notably having from 2 to 20 carbon atoms, preferably 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, caprylylglycol, dipropylene glycol, diethylene glycol; glycol ethers (notably having from 3 to 16 carbon atoms) such as mono-, di- or tri- propylene glycol (CrC₄)alkyl ethers, mono-, di- or tri-ethylene glycol (CrC₄) alkyl ethers and mixtures thereof.

The continuous hydrophilic phase of the composition of the invention may comprise water and a polyol, preferably glycerol or propylene glycol, or a monoalcohol, preferably ethanol.

Fatty phase

The solid composition of the invention further comprises a dispersed fatty phase.

The fatty phase is present in an amount ranging from 1 % to 90% by weight, preferably from 5% to 70% by weight, more preferably from 10% to 30% by weight, relative to the total weight of the composition.

Said fatty phase preferably comprises at least one oil. The oil can be volatile or non- volatile.

The term "oil" means a water-immiscible non-aqueous compound that is liquid at room temperature (25°C) and at atmospheric pressure (760 mmHg).

The term "non-volatile oil" means an oil that remains on keratin materials at room temperature and atmospheric pressure for at least several hours and that especially has a vapour pressure of less than 10^~3 mmHg (0.13 Pa). A non-volatile oil may also be defined as having an evaporation rate such that, under the conditions defined previously, the amount evaporated after 30 minutes is less than 0.07 mg/cm².

These oils may be of plant, mineral or synthetic origin.

Preferably, said oil is chosen from hydrocarbonated, silicone or fluorinated oils.

The term "hydrocarbon-based oil" or "hydrocarbonated oil" means an oil formed essentially from, or even constituted by, carbon and hydrogen atoms, and optionally O and N atomes, and free of Si and F heteroatoms. Such oil can contain alcohol, ester, ether, carboxylic acid, amine and/or amide groups.

The term "silicone oil" means an oil containing at least one silicon atom, especially containing Si-0 groups.

The term "fluorinated oil" means an oil containing at least one fluorine atom,

Preferably, the oil is selected from hydrocarbonated oils, preferably non-volatile.

The oil can be, for example, present in an amount ranging from 0.01 % to 50% by weight, preferably from 0.05% to 30% by weight, more preferably from 0.1 % to 10% by weight, relative to the total weight of the composition.

Structuring agent(s)

The solid composition of the present invention comprises structuring agents (i) and

(ii).

The composition of the present invention comprises (i) at least one structuring agent with melting point of greater than or equal to 50⁵C, and (ii) at least one structuring agent different from the structuring agent (i), having a melting point of less than or equal to 45°C.

Preferably, the structuring agents (i) and (ii) are chosen from waxes, pasty compounds, and mixtures thereof.

The wax under consideration in the context of the present invention is generally a lipophilic compound that is solid at room temperature (25°C), with a solid/liquid reversible change of state, having a melting point of greater than or equal to 30°C, preferably greater than or equal to 40⁵C, which may be up to 200°C and in particular up to 120°C.

The term "pasty compounds" within the meaning of the present invention is understood to mean a lipophilic fatty compound with a reversible solid/liquid change in state which exhibits, in the solid state, an anisotropic crystalline arrangement and which comprises, at a temperature of 23°C, a liquid fraction and a solid fraction. In other words, the starting melting point of the pasty compound can be less than 23°C. The liquid fraction of the pasty compound, measured at 23°C, can represent from 9 to 97% by weight of the pasty compound. At 23°C, this liquid fraction preferably represents between 15 and 85% by weight, more preferably between 40 and 85% by weight of the pasty compound.

Within the meaning of the invention, the melting point corresponds to the temperature of the most endothermic peak observed by thermal analysis (DSC) as described in Standard ISO 1 1357-3: 1999. The melting point of a pasty compound can be measured using a differential scanning calorimeter (DSC), for example the calorimeter sold under the name "MDSC 2920" by TA Instruments.

The measurement protocol is as follows:

A 5 mg sample of a pasty compound placed in a crucible is subjected to a first rise in temperature ranging from -20°C to 100°C at a heating rate of 10°C/minute, is then cooled from 100°C to -20°C at a cooling rate of 10°C/minute and, finally, is subjected to a second rise in temperature ranging from -20°C to 100°C at a heating rate of 5°C/minute. During the second rise in temperature, the variation in the difference in power absorbed by the empty crucible and by the crucible comprising the sample of pasty compound is measured as a function of the temperature. The melting point of the pasty compound is the value of the temperature corresponding to the tip of the peak of the curve representing the variation in the difference in power absorbed as a function of the temperature.

The liquid fraction by weight of the pasty compound at 23°C is equal to the ratio of the enthalpy of fusion consumed at 23°C to the enthalpy of fusion of the pasty compound.

The enthalpy of fusion of the pasty compound is the enthalpy consumed by the latter to change from the solid state to the liquid state. The pasty compound is "in the solid state" when the whole of its mass is in the solid crystalline form. The pasty compound is "in the liquid state" when the whole of its mass is in the liquid form.

The enthalpy of fusion of the pasty compound is equal to the area under the curve of the thermogram obtained using a differential scanning calorimeter (DSC), such as the calorimeter sold under the name MDSC 2920 by TA Instruments, with a rise in temperature of 5 or 10°C per minute, according to Standard ISO 1 1357-3:1999.

The enthalpy of fusion of the pasty compound is the amount of energy necessary to change the pasty compound from the solid state to the liquid state. It is expressed in J/g. The enthalpy of fusion consumed at 23°C is the amount of energy absorbed by the sample to change from the solid state to the state which it exhibits at 23°C, composed of a liquid fraction and of a solid fraction. The liquid fraction of the pasty compound measured at 32°C preferably represents from 30 to 100% by weight of the pasty compound, preferably from 50 to 100% by weight of the pasty compound, more preferably from 60 to 100% by weight of the pasty compound. When the liquid fraction of the pasty compound measured at 32°C is equal to 100%, the temperature of the end of the melting range of the pasty compound is less than or equal to 32°C.

The liquid fraction of the pasty compound measured at 32°C is equal to the ratio of the enthalpy of fusion consumed at 32°C to the enthalpy of fusion of the pasty compound. The enthalpy of fusion consumed at 32°C is calculated in the same way as the enthalpy of fusion consumed at 23°C.

The structuring agent (i) has a melting point greater than or equal to 50⁵C.

As illustrations that are suitable for the invention, mention may be made especially of hydrocarbon-based waxes, for instance emulsifying waxes, such as solid fatty alcohols, beeswax, lanolin wax, Chinese insect waxes, rice bran wax, carnauba wax, candelilla wax, ouricury wax, esparto grass wax, berry wax, shellac wax, Japan wax and sumac wax; montan wax, orange wax and lemon wax, microcrystalline waxes, paraffins and ozokerite; polyethylene waxes, the waxes obtained by Fischer-Tropsch synthesis and waxy copolymers, and also esters thereof, fatty acids or esters obtained by catalytic hydrogenation of animal or plant oils containing linear or branched C₈-C₃₂ fatty chains, preferably C₁₆ to C₁₈ chains, silicone waxes and fluoro waxes and mixtures thereof.

More preferably, the structuring agent (i) is selected from solid fatty alcohols.

By "solid fatty alcohol", it is meant a fatty alcohol, linear or branched, saturated or unsaturated, that is solid at room temperature (25°C) and at atmospheric pressure (780 mmHg or 1 atm.). Fatty alcohols are water-insoluble, i.e. they have a solubility in water of less than 1 % by mass and preferably less than 0.5% by weight.

Preferably, the solid fatty alcohols are of structure R— OH with R denoting a saturated or unsaturated, linear alkyl group, optionally substituted with one or more hydroxyl groups, comprising from 14 to 30 carbon atoms.

Preferably, the structuring agent (i) is a solid fatty alcohol selected from solid fatty alcohols having from 14 to 30 carbon atoms.

Preferably, solid fatty alcohols having from 14 to 30 carbon atoms may be chosen from myristyl alcohol (1 -tetradecanol), cetyl alcohol (1 -hexadecanol), palmitoleyl alcohol (cis-9-hexadecen-1 -ol), stearyl alcohol (1 -octadecanol), arachidyl alcohol (1 -eicosanol), behenyl alcohol (1 -docosanol), erucyl alcohol (cis-13-docosen-1 -ol), lignoceryl alcohol (1 - tetracosanol), ceryl alcohol (1 -hexacosanol), myricyl alcohol and melissyl alcohol (1 - triacontanol).

More preferably, according to the present invention, the solid fatty alcohol is selected from alcohols having from 14 to 22 carbon atoms, such as cetyl alcohol (1 - hexadecanol), stearyl alcohol (1 -octadecanol), arachidyl alcohol (1 -eicosanol), behenyl alcohol (1 -docosanol) and mixtures thereof.

More preferably, the solid fatty alcohol is selected from cetyl alcohol (1 - hexadecanol), stearyl alcohol (1 -octadecanol), arachidyl alcohol (1 -eicosanol), behenyl alcohol (1 -docosanol) and mixtures thereof.

When the solid fatty alcohol is a mixture, it means that several species may coexist in a commercial product, especially of different chain lengths, in the form of a mixture.

Mentions of solid fatty alcohols may be cetyl alcohol sold under the name Lanette^® 16 by BASF, or behenyl alcohol sold under the name Lanette^® 22 by the company BASF, or a mixture thereof.

According to one embodiment, the structuring agent (i) is present in an amount ranging from 0.01 % to 10%, preferably from 0.05 to 5% by weight, more preferably from 0.1 % to 3% by weight, relative to the total weight of the composition.

The structuring agent (ii) is different from the structuring agent (i) and has a melting point of less than or equal to 45°C.

Preferably, the melting point of the structuring agent (ii) is between 38°C to 45°C. Preferably, it may be a wax, a pasty compound, or a mixture thereof.

Preferably, it is a wax having a melting point of between 38°C to 45°C, such as linear esters.

Linear esters that are suitable for use in the invention are preferably chosen from the group consisting of stearyl stearate, tetradecyl tetradecanoate (INCI name: myristyl myristate), cetyl myristate, stearyl myristate, myristyl palmitate, stearyl palmitate, myristyl stearate, cetyl stearate, stearyl stearate and cetyl palmitate, and mixtures thereof.

More particularly, tetradecyl tetradecanoate, such as the one sold under the name Tegosoft MM by the company Evonik Goldschmidt, is used in the composition of the present invention.

Preferably, suitable pasty compounds that may be used as structuring agent (ii) in the present invention are esters, preferably chosen from butters of plant origin.

Such structuring agents (ii) are, for example, mango butter, such as the product sold under the reference Lipex 203 by the company Aarhuskarlshamn; shea butter, in particular the product whose INCI name is Butyrospermum Parkii Butter, such as the product sold under the references Lipex 202, and Lipex 102 by the company Aarhuskarlshamn; cupuacu butter (Rain Forest RF3410 from the company Beraca Sabara); murumuru butter (Rain Forest RF3710 from the company Beraca Sabara), cocoa butter; and also orange wax, for instance the product sold under the reference Orange Peel Wax by the company Koster Keunen, or a mixture thereof.

According to a preferred embodiment, the structuring agent (ii) is selected from the group consisting of linear esters, butters of plant origin, and mixtures thereof.

Preferably, the structuring agent (ii) is selected from the group consisting of tetradecyl tetradecanoate, shea butter and mixtures thereof.

Preferably, the structuring agent (ii) is present in an amount ranging from 0.01 % to 20%, preferably from 0.05 to 15% by weight, more preferably from 0.1 % to 10% by weight, relative to the total weight of the composition.

Surfactant(s) of alkylpolvqlvcoside type

The composition according to the invention further comprises at least one surfactant of alkylpolyglycoside type.

For the purposes of the present invention, the term "alkylpolyglycoside" is intended to mean an alkylmonosaccharide (degree of polymerization 1 ) or an alkylpolysaccharide (degree of polymerization greater than 1 ).

The alkylpolyglycosides may be used alone or in the form of mixtures of several alkylpolyglycosides. They generally correspond to the following structure (I):

R(0)(G)_x (I)

in which the radical R is a linear or branched C₁₂-C₂₂ alkyl radical, preferably a C₁₂-C₂₀ alkyl radical, G is a saccharide residue and x ranges from 1 to 5, preferably from 1 .05 to 2.5 and more preferentially from 1 .1 to 2.

The saccharide residue may be chosen from the group of glucose, dextrose, saccharose, fructose, galactose, maltose, maltotriose, lactose, cellobiose, mannose, ribose, dextran, talose, allose, xylose, levoglucan, cellulose and starch. More preferentially, the saccharide residue denotes glucose.

It should also be noted that each unit of the polysaccharide part of the alkylpolyglycoside may be in a or β isomer form, in L or D form, and the configuration of the saccharide residue may be of furanoside or pyranoside type.

It is, of course, possible to use mixtures of alkylpolysaccharides, which may differ from each other in the nature of the borne alkyl unit and/or the nature of the bearing polysaccharide chain. The surfactant of alkylpolyglycoside type may be present in a composition of the invention in a content ranging from 0.001 % to 5% by weight, preferably ranging from 0.01 % to 3% by weight, relative to the total weight of the composition.

In addition, it is particularly advantageous, according to the present invention, to use together a fatty alcohol and an alkylpolyglycoside of which the alkyl part is identical to that of the selected fatty alcohol.

Fatty alcohol/alkylpolyglycoside emulsifying mixtures as defined are described in particular in patent applications WO 92/06778, WO 95/13863 and WO 98/47610.

Among the fatty alcohol/alkylpolyglycoside mixtures that are particularly preferred, mention may be made of the products sold by the company SEPPIC under the name Montanov^®, such as the following mixtures:

o cetylstearyl alcohol/cocoyl glucoside— Montanov 82^®,

o arachidyl alcohol and behenyl alcohol/arachidyl glucoside— Montanov 802^®,

o myristyl alcohol/myristyl glucoside— Montanov 14^®,

o cetylstearyl alcohol/cetylstearyl glucoside— Montanov 68^®,

o C14-C22 alcohol/Ci2-C₂₀ alkyl glucoside— Montanov L ,

o cocoyl alcohol/cocoyl glucoside— Montanov S^®, and

o isostearyl alcohol/isostearyl glucoside— Montanov WO 18^®.

According to one particular embodiment, the alkylpolyglycoside used in a composition according to the invention is C₁₂-C₂₀ glucoside. It is advantageously used as a mixture with a C₁₄-C₂₂ alcohol.

According to one particular embodiment of the invention, use is thus made of the

C₁₄-C₂₂ alcohol/C₁₂-C₂₀ alkylglucoside mixture, such as the product sold by the company

SEPPIC under the name Montanov 68^®, consisting of approximately 20% of C₁₂-C₂₀ alkylglucoside and of approximately 80% of C₁₄-C₂₂ alcohol.

Non-ionic surfactant(s) of ester type

The composition according to the invention comprises at least one non-ionic surfactant of ester type, which is particularly a mixture of at least an ester obtained by esterification of a solid wax with a polyol, of a fatty acid diester with a polyglycerol, of a jojoba wax (preferably a jojoba wax ester), and of a fatty alcohol. Said ester is non-ionic. Said non-ionic surfactant of ester type comprises a mixture of at least one monounsaturated ester and at least one polyglyceryl diester.

According to an embodiment, the non-ionic surfactant of ester type comprises:

i) at least one monounsaturated ester of formula (A), R1 -C(0)-0-R2 (A)

wherein:

R1 and R2 represent, respectively, a C18 to C44 fatty chain, at least one of R1 or R2 is monounsaturated;

ii) at least one polyglyceryl diester of formula (B),

R3-C(0)-(0-CH2-CH(OH)-CH2)n-0-C(0)-R4 (B) wherein:

R3 and R4 represent, respectively, a saturated C18 to C44 fatty chain, linear or branched, and

iii) at least one C10-C30 fatty alcohol.

According to an embodiment, in the formula (A), R1 and R2 represent, respectively, a C18-C40 fatty chain, more preferably a C18-C30 fatty chain. At least one of R1 or R2 is monounsaturated.

More specifically, in formula (A), the R1— C(O) group corresponds to the carbon chain of the fatty acid. This chain may be linear or monounsaturated, and comprises at least 18 carbon atoms. Mention can be made of oleic (C18:1 ), gadoleic (C20:1 ), erucic (C22:1 ) acid, up to hexaconenoic (C26:1 ) acid for unsaturated acids. The R1— C(O) group may also consist of branched and saturated acids of at least 18 carbon atoms, also called Guerbet acids. The R2— O— group may consist of monounsaturated linear fatty alcohols with at least 18 carbon atoms. Mention can therefore be made of octadecenol, eicosenol, docosenol and hexacosenol. The carbon chain of the alcohol may also be branched and saturated and comprise at least 18 carbon atoms. Such alcohols are also called Guerbet alcohols.

Preferably, the monounsaturated ester of the formula (A) is a mixture of esters comprising various lengths of fatty chains in their structures. More preferably, such a monounsaturated ester is liquid at ambient temperature.

A preferred monounsaturated ester can be mentioned is, for example, the product commonly called jojoba oil (or jojoba esters), the liquid nature being due to the presence of monounsaturated chains. This oil comprises in particular C18:1 (preferably minority), C20:1 and C22:1 (preferably majority with C20:1 >C22:1 ) unsaturated fatty acid esters, with C20:1 , C22:1 and C24:1 unsaturated fatty alcohols.

According to an embodiment, in the formula (B), the R3— C(O)— group corresponds to the carbon chain of C18 to C44 fatty acid, said acid usually being linear and saturated, preferably corresponds to a linear and saturated C20 to C34 fatty acid. This therefore includes eicosanoic (or arachidic) acid (C20), docosanoic (or behenic) acid (C22), tetracosanoic (or lignoceric) acid (C24), hexacosanoic (or cerotic) acid (C26). The R4 group corresponds to the hydrocarbon chain of the alcohol, said alcohol usually being saturated linear and having a C18 to C44 chain, preferably C20 to C34 chain, n is an integer between 2 to 6.

According to the present invention, the polyglyceryl diester is obtained by esterification of a solid wax in the presence of at least one polyol.

Depending on the source of the wax, the mixture of monoesters may also contain a certain proportion of hydroxyacid esters such as hydroxypalmitic or hydroxystearic acid. This is the case for example of beeswax. Preferably said alcohol is eicosanol, docosanol or tetracosanol. Beeswax, carnauba wax, candelilla wax, rice bran wax, sunflower wax, ouricury wax, Shellac wax and sugarcane wax are examples of natural solid waxes. Preferably, the solid wax is beeswax.

Solid waxes suitable for obtaining the polyglyceryl diester have a melting point between 50 and 90°C. They correspond to mixtures essentially comprising monoesters having the formula R¹— C(O)— O— R², where the R¹— C(O)— group corresponds to the carbon chain of the fatty acid, said acid usually being linear and saturated and having a number of carbon atoms of at least 18, and in particular 20, and preferably up to 44 and preferably 34. This therefore includes eicosanoic (or arachidic) acid (C20), docosanoic (or behenic) acid (C22), tetracosanoic (or lignoceric) acid (C24), hexacosanoic (or cerotic) acid (C26). Depending on the source of the wax, the mixture of monoesters may also contain a certain proportion of hydroxyacid esters such as hydroxypalmitic or hydroxystearic acid. This is the case for example of beeswax. The R² group corresponds to the hydrocarbon chain of the alcohol, said alcohol usually being saturated linear and having a number of carbon atoms of at least 18, and in particular 20, and preferably up to 44 and preferably 34. Preferably said alcohol is eicosanol, docosanol or tetracosanol. Beeswax, carnauba wax, candelilla wax, rice bran wax, sunflower wax, ouricury wax, Shellac wax and sugarcane wax are examples of natural solid waxes.

Preferably, the solid wax suitable for the esterification reaction is beeswax.

Preferably, the polyol used for esterification is selected from the group comprising ethylene glycol, diethylene glycol, triethylene glycol, 2-methyl propanediol, propylene glycol, butylene glycol, neopentyl glycol, hexylene glycol, octylene glycol, polyethylene glycol, polypropylene glycol, trimethylol propane, sorbitol, erythritol, pentaerythritol, dipentaerythritol, glycerol, diglycerol and polyglycerol (i.e. a polymer of glycerol units). More preferably, the polyol is a polyglycerol, having an average degree of polymerization between 2 and 6, preferably of 3. Preferably, the polyol is polyglycerol-3. The non-ionic ester surfactant also comprises the acid part of a solid wax. Waxes have a complex composition. They have the common feature of containing a mixture of acid monoesters and very long chain fatty alcohols.

Preferably, the non-ionic ester surfactant is a wax derivative obtained by reacting together at least one solid wax and at least one monounsaturated ester of formula (A) in the presence of at least one polyol and optionally at least one catalyst. In such a case, a transesterification reaction occurs between the various chemical entities yielding the wax derivative.

The preferred catalysts are hydroxides or alkaline or alkaline earth alkoxides, calcium hydroxide, potassium or sodium carbonates or catalysts based on tin or titanium.

Preferably, the solid wax is advantageously selected from the group comprising carnauba wax, candelilla wax, rice bran wax, sunflower wax, sugarcane wax, ouricury wax, beeswax and Shellac wax.

In a preferred embodiment, the wax derivative is obtained by reacting jojoba oil (also called as jojoba wax), beeswax and a polyglycerol, such as polyglycerol-3.

In practice, the reaction is preferably conducted at a temperature of between 100°C and 220°C, advantageously between 150°C and 200°C. Preferably, the monounsaturated ester/solid wax mass ratio varies between 5/95 and 95/5, advantageously between 30/70 and 75/25. The esters of formula (A) and (B)/polyol mass ratio preferably varies between 1/99 and 99/1 , advantageously between 95/5 and 50/50. Preferably, the proportion of esterified polyol represents between 0.5 and 50% by weight of the mixture, the proportion of esterified fatty acids represents between 20 and 60% by weight of the mixture and the proportion of esterified fatty alcohols between 20 and 60% by weight of the mixture.

Preferably, the non-ionic ester surfactant is further present with a diester of a C₁₄-

C₂₂ fatty acid with a polyglycerol.

Typically, the Ci₄-C₂₂ fatty acid may be chosen from the group of myristic acid, stearic acid, isostearic acid, palmitic acid, oleic acid, behenic acid, erucic acid and arachidic acid, and mixtures thereof.

The polyglycerol may be a polymer of glycerol units, preferably a polymer having an average degree of polymerization between 4 and 8, preferably of 6.

Preferably, said diester is a diester of distearic acid with hexaglycerol. Preferably, it is polyglyceryl-6 distearate. According to one particular mode of the invention, the non-ionic ester type surfactant according to the invention comprises at least one fatty alcohol containing from 10 to 30 carbon atoms.

As examples of fatty alcohols that may be used, mention may be made of linear or branched fatty alcohols, of synthetic origin or alternatively of natural origin, for instance alcohols originating from vegetable material (coconut, palm kernel, palm, etc.) or animal material (tallow, etc.). Use is preferably made of a fatty alcohol comprising from 20 to 26 carbon atoms, preferably from 10 to 24 carbon atoms and more preferentially from 12 to 22 carbon atoms.

As particular examples of fatty alcohols that may be used in the context of the present invention, mention may in particular be made of lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, palmityl alcohol, oleyl alcohol, cetearyl alcohol (mixture of cetyl alcohol and stearyl alcohol), behenyl alcohol, erucyl alcohol and arachidyl alcohol, and mixtures thereof.

In addition, it is particularly advantageous, according to the present invention, to use together a mixture of polyglyceryl-6 distearate and polyglyceryl-3 beeswax, with cetyl alcohol and jojoba wax. Among the mixtures that are particularly preferred, mention may be made of the product sold by the company Gattefosse under the name Emulium^® Mellifera, comprising jojoba wax, cetyl alcohol, polyglyceryl-6 distearate, and polyglyceryl- 3 beeswax (INCI name: Polyglyceryl-6 Distearate (and) Jojoba Esters (and) Polyglyceryl-3 Beeswax (and) Cetyl Alcohol). Said mixture comprises from 5 to 30% by weight of the total weight of the mixture of jojoba wax; from 3 to 15% by weight of cetyl alcohol; at least 50% by weight of polyglyceryl-6 distearate; and from 3 to 15% by weight of polyglyceryl-3 beeswax.

The non-ionic ester surfactant may be present in a composition of the invention in a content ranging from 0.1 % to 10% by weight, preferably from 0.5% to 5% by weight, relative to the total weight of the composition.

According to a particularly preferred embodiment, the present invention relates to a solid composition in form of oil-in-water emulsion, comprising:

(i) at least one structuring agent with a melting point of greater than or equal to 50⁵C, selected from the group consisting of solid fatty alcohols having from 14 to 30 carbon atoms;

(ii) at least one structuring agent different from (i), having a melting point of less than or equal to 45°C, selected from the group consisting of linear esters, butters of plant origin and mixtures thereof; (iii) at least one surfactant of alkylpolyglycoside type; and

More particularly, the invention relates to a solid composition in form of oil-in-water emulsion, comprising, relative to the total weight of the composition:

(i) from 0.05 to 5% by weight of solid fatty alcohols having from 14 to 30 carbon atoms;

(ii) from 0.05 to 15% by weight of at least one linear ester having a melting point of less than or equal to 45°C;

(iii) from 0.01 % to 3% by weight of at least one Ci₂-C₂₀ alkylpolyglucoside; and

(iv) from 0.5% to 5% by weight of at least one non-ionic surfactant of ester type, comprising a mixture of at least one monounsaturated ester and at least one polyglyceryl diester.

Additional ingredients

The solid composition of the invention may comprise other ingredients, such as anionic, amphoteric or zwitterionic surfactants.

It may also further comprise at least one additive. A person skilled in the art can adjust the type and amount of additives present in the compositions according to the invention by means of routine operations, so that the desired cosmetic properties and stability properties for these compositions are not affected by the additives. Said additive may be chosen from thickeners, active agents and preservatives.

Methods and use

According to an embodiment, the present invention relates to a non-therapeutic method for treating a keratin material, comprising the step of applying the composition of the present invention to the keratin material.

Preferably the present invention relates to a method for caring for the skin, comprising the step of applying the composition of the present invention to the skin.

According to another embodiment, the invention relates to the use of a composition of the present invention for moisturizing a keratin material, especially the skin.

The following examples serve to illustrate the invention without, however, being limiting in nature. EXAMPLES Example 1 : Preparation of a solid composition according to the present invention

A solid composition according to the invention was prepared according to the amounts given in the table below. The amounts are given in % by weight of the total composition.

Example 2: Evaluation

The usage and cosmetic properties of the solid composition according to the present invention in Example 1 (solid balm) were measured. The yield stress of the solid balm was measured using the machine Physica MCR 301 produced by the company Anton Paar under under a shear rate from 0.1 to 40 s^~1 , following the method described above.

The hardness of the solid balm was measured as well, using the machine Texture analyser sold by Lotun science co.Ltd, following the method described previously.

Then the solid composition of the present invention in Example 1 was given to 5 consumers to be applied on the skin, and score of easy pick up, easy spreading, as well as fresh and moisturizing feeling were given by the consumers:

1 : very poor;

2: little effect, not acceptable;

3: acceptable;

4: good effect;

5: very good effect, very easy to pick up and spread, fresh on the skin.

The results are as follow:

It is observed from the result above, that the solid composition of the present invention in Example 1 is easy to pick up by fingers, easy to spread on the skin, and provides to the skin fresh and moisturizing feeling. Its hardness and yield stress are both in the desired ranges.

Claims

1. Solid composition in form of oil-in-water emulsion, comprising:

(i) at least one structuring agent with a melting point of greater than or equal to 50⁵C, (ii) at least one structuring agent different from (i), having a melting point of less than or equal to 45°C,

(iii) at least one surfactant of alkylpolyglycoside type; and

2. Solid composition of claim 1 , wherein the structuring agent (i) is selected from the group consisting of hydrocarbon-based waxes, montan wax, orange wax and lemon wax, microcrystalline waxes, paraffins and ozokerite; polyethylene waxes, the waxes obtained by Fischer-Tropsch synthesis and waxy copolymers, and also esters thereof, fatty acids or esters obtained by catalytic hydrogenation of animal or plant oils containing linear or branched C₈-C₃₂ fatty chains, preferably Ci₆ to Ci₈ chains, silicone waxes, fluoro waxes and solid fatty alcohols of structure R— OH, with R denoting a saturated or unsaturated, linear alkyl group, optionally substituted with one or more hydroxyl groups, comprising from 14 to 30 carbon atoms.

3. Solid composition of claim 1 or 2, wherein the structuring agent (i) is selected from the group consisting of emulsifying waxes, preferably chosen from solid fatty alcohols, beeswax, lanolin wax, Chinese insect waxes, rice bran wax, carnauba wax, candelilla wax, ouricury wax, esparto grass wax, berry wax, shellac wax, Japan wax and sumac wax.

4. Solid composition of any one of claims 1 to 3, wherein the structuring agent (i) is a solid fatty alcohol having from 14 to 30 carbon atoms, preferably chosen from myristyl alcohol, cetyl alcohol, palmitoleyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, erucyl alcohol, lignoceryl alcohol, ceryl alcohol, myricyl alcohol and melissyl alcohol.

5. Solid composition of any one of claims 1 to 4, wherein the structuring agent (i) is present in an amount ranging from 0.01 % to 10%, preferably from 0.05 to 5% by weight, more preferably from 0.1 % to 3% by weight, relative to the total weight of the composition.

6. Solid composition of any one of the preceding claims 1 to 5, wherein the structuring agent (ii) is selected from the group consisting of linear esters, butters of plant origin and mixtures thereof.

7. Solid composition of any one of the preceding claims 1 to 6, wherein the structuring agent (ii) is chosen from the group consisting of stearyl stearate, tetradecyl tetradecanoate, cetyl myristate, stearyl myristate, myristyl palmitate, stearyl palmitate, myristyl stearate, cetyl stearate, stearyl stearate and cetyl palmitate, mango butter, shea butter, cupuacu butter, murumuru butter, cocoa butter, and orange wax.

8. Solid composition of any one of the preceding claims 1 to 7, wherein the structuring agent (ii) is present in an amount ranging from 0.01 % to 20%, preferably from 0.05 to 15% by weight, more preferably from 0.1 % to 10% by weight, relative to the total weight of the composition.

9. Solid composition of any one of the preceding claims 1 to 8, wherein the surfactant of alkylpolyglycoside type is selected from the compound of formula (I),

R(0)(G)_x (I)

in which the radical R is a linear or branched Ci₂-C₂₂ alkyl radical, x ranges from 1 to 5 and G is a saccharide residue chosen from the group of glucose, dextrose, saccharose, fructose, galactose, maltose, maltotriose, lactose, cellobiose, mannose, ribose, dextran, talose, allose, xylose, levoglucan, cellulose and starch; preferably, G is glucose.

10. The composition as claimed in any one of claims 1 to 9, characterized in that the surfactant of alkylpolyglycoside type is present in a content ranging from 0.001 % to 5% by weight, preferably ranging from 0.01 % to 3% by weight, relative to the total weight of the composition.

11. The composition as claimed in any one of claims 1 to 10, characterized in that said non-ionic surfactant of ester type comprises:

i) at least one monounsaturated ester of formula (A),

R1 -C(0)-0-R2 (A)

wherein:

R1 and R2 represent, respectively, a C18 to C44 fatty chain, at least one of R1 or R2 is monounsaturated; ii) at least one polyglyceryl diester of formula (B),

R3-C(0)-(0-CH2-CH(OH)-CH2)n-0-C(0)-R4 (B) wherein:

iii) at least one C10-C30 fatty alcohol;

preferably, the non-ionic surfactant of ester type comprises at least one monounsaturated ester of formula (A) wherein R1 and R2 represent, respectively, a C18-C30 fatty chain, and at least one of R1 or R2 is monounsaturated; at least one polyglyceryl diester of formula (B) wherein, R3-C(0)- and R4 each represent a saturated C20 to C34 fatty chain, linear or branched; and cetyl alcohol.

12. The composition as claimed in claim 1 1 , characterized in that it further comprises a diester of a C₁₄-C₂₂ fatty acid with a polyglycerol and/or a fatty alcohol containing from 10 to 30 carbon atoms.

13. The composition of any one of the preceding claims 1 to 12, wherein the non-ionic surfactant of ester type is a mixture of polyglyceryl-6 distearate, jojoba esters, polyglyceryl-3 beeswax, and cetyl alcohol.

14. The composition of any one of the preceding claims 1 to 13, wherein the non-ionic ester surfactant may be present in a content ranging from 0.1 % to 10% by weight, preferably from 0.5% to 5% by weight, relative to the total weight of the composition.

15. A method for caring for the skin, comprising the application to the skin of the solid composition of any one of claims 1 to 14.