WO2012041632A1

WO2012041632A1 - Anhydrous fluid filtering composition free of c1-c5 alkanol, comprising a lipophilic polyamide polycondensate and a volatile alkane

Info

Publication number: WO2012041632A1
Application number: PCT/EP2011/065109
Authority: WO
Inventors: Cyril Chevalier; Carole Guiramand
Original assignee: L'oreal
Priority date: 2010-09-30
Filing date: 2011-09-01
Publication date: 2012-04-05
Also published as: FR2965480A1; FR2965480B1

Abstract

The present invention relates to an anhydrous fluid composition free of C₁-C₅ alkanol, comprising, in a cosmetically acceptable medium: a) at least one lipophilic polyamide polycondensate, and b) at least one linear or branched volatile alkane, and c) at least one lipophilic organic UV-screening agent.

Description

ANHYDROUS FLUID FILTERING COMPOSITION FREE OF d-C₅ ALKANOL, COMPRISING A LIPOPHILIC POLYAMIDE POLYCONDENSATE AND A VOLATILE ALKANE The present invention relates to an anhydrous fluid composition free of C1 -C5 alkanol, comprising, in a cosmetically acceptable medium:

a) at least one lipophilic polyamide polycondensate, and

b) at least one linear or branched volatile alkane, and

c) at least one lipophilic organic UV-screening agent.

It is known that light radiation with wavelengths of between 280 nm and 400 nm permits tanning of the human epidermis and that light rays with wavelengths more particularly between 280 and 320 nm, known as UV-B rays, cause skin burns and erythema which can harm the development of a natural tan. For these reasons, and also for aesthetic reasons, there is constant demand for means for controlling this natural tanning in order thus to control the colour of the skin; this UV-B radiation should thus be screened out.

It is also known that UV-A rays, with wavelengths between 320 and 400 nm, which cause tanning of the skin, are liable to induce adverse changes therein, in particular in the case of sensitive skin or skin that is continually exposed to solar radiation. UV-A rays cause in particular a loss of elasticity of the skin and the appearance of wrinkles leading to premature ageing of the skin. They promote triggering of the erythemal reaction or amplify this reaction in certain individuals and may even be the cause of phototoxic or photoallergic reactions. Thus, for aesthetic and cosmetic reasons, for instance conservation of the skin's natural elasticity, people increasingly wish to control the effect of UV-A rays on their skin. It is thus desirable also to screen out UV-A radiation. For the purpose of protecting the skin and keratin materials against UV radiation, antisun compositions comprising organic screening agents that are active in the UV-A range and in the UV-B range are generally used.

Many cosmetic compositions for photoprotecting the skin (against UV-A and/or UV-B) have been proposed to date. Fluid formulations that are easy for the users to apply to the skin are most particularly sought.

Among the fluid antisun compositions proposed hitherto, anhydrous formulations of antisun oil type are particularly sought on account of their easy and pleasant application to the skin and their good water resistance. However, they are not particularly widespread on the antisun products market due to the fact that it is difficult to obtain a sun protection factor of greater than 10 and also a UVA protection factor that satisfies the ratio stipulated by the various regulations or recommended by the regulation concerning antisun products, especially of greater than 5.

The sun protection factor (SPF) is expressed mathematically as the ratio of the irradiation time necessary to reach the erythema-forming threshold with the UV- screening agent to the time necessary to reach the erythema-forming threshold without UV-screening agent. It is evaluated in vivo especially according to the international method published by Colipa / CTFA SA / JCIA (May 2006). To characterize the protection with respect to UV-A, the PPD (persistent pigment darkening) method, which measures the skin colour observed 2 to 4 hours after exposure of the skin to UV-A, is particularly recommended and used. This method has been adopted since 1996 by the Japanese Cosmetic Industry Association (JCIA) for the UV-A labelling of products and is frequently used by test laboratories in Europe and the United States (Japan Cosmetic Industry Association Technical Bulletin. Measurement Standards for UVA protection efficacy. Issued November 21 , 1995 and effective as of January 1 , 1996).

The UVAPPD protection factor (UVAp_PD PF) is expressed mathematically by the ratio of the UV-A radiation dose necessary to reach the pigmentation threshold with the UV-screening agent (MPPDp) to the UV-A radiation dose necessary to reach the pigmentation threshold without UV-screening agent (MPPDnp).

FP UVA^ . ^

MPPDnp

Specifically, the main difficulties encountered in the manufacture of antisun oils for attempting to increase the sun protection factors are those of obtaining a formulation that is fluid, transparent and also stable, and that is cosmetically pleasant

It has already been proposed in patent applications EP 1 813 266 and EP 2 014 277 to use in emulsion-type aqueous fluid antisun compositions lipophilic polyamide polycondensates, in particular a poly(ester-amide) polymer bearing ester end groups (ETPEA) or a polyamide polymer bearing tertiary amide end groups (ATPA) in order to obtain high sun protection factors.

In the course of its investigations, the Applicant Company has found that on using this type of lipophilic polyamide polycondensate in a fluid antisun anhydrous composition of the antisun oil type, the formulation does not remain fluid and becomes too thick (formation of a gel) and sparingly cosmetic. Furthermore, during storage after 2 months, the formulation thus obtained has a tendency to become heterogeneous with exudation of oil: mixture of gelled and non-gelled parts.

To overcome this problem, it has already been proposed in the unpublished patent applications FR 0952038 and FR 0958876 to use antisun oils comprising at least one C1 -C5 alkanol (ethanol) with an oil thickener and oils commonly used in antisun formulations, for example caprylic/capric acid 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; synthetic esters, for instance C12-C15 alcohol benzoates, for instance the product sold under the trade name Finsolv TN or Witconol TN by the company Witco, or Tegosoft TN by the company Evonik Goldschmidt, and diisopropyl sebacate, such as the product sold under the trade name Dub DIS by the company Stearineries Dubois. The presence of ethanol in these antisun oils is fundamental due to the fact that it affords them fluidity while at the same time maintaining their transparency, stability and feel. However, the presence of alcohol in formulations of this type presents drawbacks:

- some consumers prefer alcohol-free cosmetic products for reasons of odour and tolerance

- during the production of formulations with alcohol, industrial equipment that is more safety-oriented is obligatory; this is likewise the case as regards the transportation and storage of these products.

Alcohol-free antisun oils with SPF values that may be up to 10, 15 or even 20 are now known on the antisun products market. However, these alcohol-free oils contain raw materials that are not entirely satisfactory either environmentally or as regards their tolerance.

There is thus a need to find novel anhydrous antisun compositions free of C1-C5 alkanols, which are fluid, transparent and stable over time and which can reach high sun protection factors (SPF) and UVA protection factors, and which can be easily stored and manufactured without the constraints imposed by the Ci-C5 alkanols of the oils of the prior art, and without the drawbacks mentioned previously. The Applicant Company has now discovered, surprisingly, that this objective can be achieved with a fluid anhydrous composition comprising, in a cosmetically acceptable medium:

a) at least one lipophilic polyamide polycondensate, and

b) at least one linear or branched volatile alkane, and

c) at least one lipophilic organic UV-screening agent.

This discovery forms the basis of the present invention.

The present invention thus relates to an anhydrous fluid composition free of C1-C5 alkanol, comprising, in a cosmetically acceptable medium:

a) at least one lipophilic polyamide polycondensate, and

b) at least one linear or branched volatile alkane, and

c) at least one lipophilic organic UV-screening agent. Other characteristics, aspects and advantages of the invention will emerge on reading the detailed description that follows.

The term "cosmetically acceptable" means compatible with the skin and/or its integuments, which has a pleasant colour, odour and feel, and which does not cause any unacceptable discomfort (stinging, tautness or redness) liable to dissuade the consumer from using this composition.

For the purposes of the invention, the term "fluid composition" means a composition that is not in solid form and whose viscosity, measured using a Rheomat 180 viscometer at 25°C at a spin speed of 200 rpm after 30 seconds of rotation, is less than 0.5 Pa.s, more preferentially less than 0.2 Pa.s and more particularly ranging from 0.0001 Pa.s to 0.1 Pa.s.

The term "anhydrous composition" means a composition containing less than 1 % by weight of water, or even less than 0.5% water, and especially free of water, the water not being added during the preparation of the composition but corresponding to the residual water provided by the mixed ingredients.

The term "C1-C5 alkanol" means any compound having a saturated alkyl chain of 1 to 5 carbon atoms comprising only one hydroxyl function and chosen especially from methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol and t- butanol.

The term "composition free of C1-C5 alkanol" means a composition containing less than 1 % by weight of C1-C5 alkanol and preferentially less than 0.5% by weight of C1-C5 alkanol, more preferentially totally free of C1-C5 alkanol.

LIPOPHILIC POLYAMIDE POLYCONDENSATE For the purposes of the invention, the term "polycondensate" means a polymer obtained by polycondensation, i.e. by chemical reaction between monomers bearing different functional groups chosen in particular from acid, alcohol and amine functions. For the purposes of the invention, the term "polymer" means a compound containing at least two repeating units, preferably at least three repeating units and better still ten repeating units.

The lipophilic polyamide polycondensate(s) are preferably present in the compositions of the invention in concentrations ranging from 0.1 % to 15% by weight and more preferentially from 1 % to 8% by weight relative to the total weight of the composition.

The lipophilic polyamide polycondensates may be chosen especially from polyamide polymers comprising a) a polymer backbone containing hydrocarbon- based repeating units bearing at least one non-pendent amide unit, and optionally b) at least one pendent fatty chain and/or at least one terminal fatty chain, which are optionally functionalized, comprising at least four carbon atoms and being bonded to these hydrocarbon-based units.

For the purposes of the invention, the term "functionalized chains" means an alkyl chain comprising one or more functional groups or reagents chosen especially from amide, hydroxyl, ether, oxyalkylene or polyoxyalkylene, halogen, including fluoro or perfluoro groups, and ester, siloxane and polysiloxane groups. In addition, the hydrogen atoms of one or more fatty chains may be at least partially replaced with fluorine atoms.

For the purposes of the invention, the term "hydrocarbon-based repeating units" means a unit comprising from 2 to 80 carbon atoms and preferably from 2 to 60 carbon atoms, bearing hydrogen atoms and optionally oxygen atoms, which may be linear, branched or cyclic, and saturated or unsaturated. These units each also comprise at least one amide group that is advantageously non-pendent, which is in the polymer backbone. The pendent chains are advantageously bonded directly to at least one of the nitrogen atoms of the polymer backbone.

The lipophilic polyamide polycondensate may comprise between the hydrocarbon- based units silicone units or oxyalkylene units.

In addition, the lipophilic polyamide polycondensate of the composition of the invention advantageously comprises from 40% to 98% of fatty chains relative to the total number of amide units and fatty chains, and better still from 50% to 95%.

The pendent fatty chains are preferably bonded to at least one of the nitrogen atoms of the amide units of the polymer. In particular, the fatty chains of this polyamide represent from 40% to 98% of the total number of amide units and of fatty chains, and better still from 50% to 95%.

Advantageously, the lipophilic polyamide polycondensate has a weight-average molecular mass of less than 100 000 (especially ranging from 1000 to 100 000), in particular less than 50 000 (especially ranging from 1000 to 50 000) and more particularly ranging from 1000 to 30 000, preferably from 2000 to 20 000 and better still from 2000 to 10 000.

The lipophilic polyamide polycondensate is insoluble in water, especially at 25°C. In particular, it contains no ionic groups. As preferred lipophilic polyamide polycondensates that may be used in the invention, mention may be made of polyamides branched with pendent fatty chains and/or terminal fatty chains containing from 6 to 120 carbon atoms and better still from 8 to 120 and in particular from 12 to 68 carbon atoms, each terminal fatty chain being bonded to the polyamide backbone via at least one bonding group L. The bonding group L may be chosen from ester, ether, amine, urea, urethane, thioester, thioether, thiourea and thiourethane groups. Preferably, these polymers comprise a fatty chain at each end of the polyamide backbone.

These polymers are preferably polymers resulting from a polycondensation between a dicarboxylic acid containing at least 32 carbon atoms (in particular containing from 32 to 44 carbon atoms) and an amine chosen from diamines containing at least 2 carbon atoms (in particular from 2 to 36 carbon atoms) and triamines containing at least 2 carbon atoms (in particular from 2 to 36 carbon atoms). The diacid is preferably a dimer of a fatty acid containing ethylenic unsaturation containing at least 16 carbon atoms, preferably from 16 to 24 carbon atoms, for instance oleic acid, linoleic acid or linolenic acid. The diamine is preferably ethylenediamine, hexylenediamine or hexamethylenediamine. The triamine is, for example, ethylenetriamine. For the polymers comprising one or two terminal carboxylic acid groups, it is advantageous to esterify them with a monoalcohol containing at least four carbon atoms, preferably from 10 to 36 carbon atoms, better still from 12 to 24 and even better from 16 to 24, for example 18 carbon atoms.

The lipophilic polyamide polycondensate of the composition according to the invention may be chosen in particular from the polymers of formula (A) below:

in which:

n is an integer ranging from 1 to 30;

R'i represents independently in each case a fatty chain and is chosen from an alkyl or alkenyl group containing at least 1 carbon atom and especially from 4 to 24 carbon atoms;

R'₂ represents independently in each case a hydrocarbon-based radical comprising from 1 to 52 carbon atoms;

R'₃ represents independently in each case an organic group comprising at least one atom chosen from carbon, hydrogen and nitrogen atoms, on condition that R'₃ comprises at least three carbon atoms;

R'₄ represents independently in each case: a hydrogen atom, an alkyl group comprising from 1 to 10 carbon atoms, or a direct bond to at least one group chosen from R'₃ and another R'₄ such that when the said group is another R'4, the nitrogen atom to which are attached both R'₃ and R'₄ forms part of a heterocyclic structure defined by R'₄-N-R'₃, on condition that at least 50% of the R'₄ represent a hydrogen atom, and

L represents a bonding group preferably chosen from ester, ether, amine, urea, urethane, thioester, thioether, thiourea and thiourethane, optionally substituted with at least one group R'i as defined above.

According to one embodiment, these polymers are chosen from the polymers of formula (A) in which the bonding group L represents an ester group

- C— O—

0

These polymers are more especially those described in document

5,783,657 from the company Union Camp.

Each of these polymers in particular satisfies formula (B) below:

in which:

- m denotes a whole number of amide units such that the number of ester groups represents from 10% to 50% of the total number of ester and amide groups; Ri is independently in each case an alkyl or alkenyl group containing at least 4 carbon atoms and especially from 4 to 24 carbon atoms;

- R₂ represents independently in each case a C₄ to C₄2 hydrocarbon-based group, on condition that 50% of the groups R₂ represent a C30 to C₄2 hydrocarbon-based group;

- R₃ represents independently in each case an organic group bearing at least two carbon atoms, hydrogen atoms and optionally one or more oxygen or nitrogen atoms;

- and R₄ represents independently in each case a hydrogen atom, a Ci to C10 alkyl group or a direct bond to R₃ or to another R₄ such that the nitrogen atom to which are attached both R₃ and R₄ forms part of a heterocyclic structure defined by R₄-N-R₃, with at least 50% of the groups R₄ representing a hydrogen atom.

In the particular case of formula (B), the terminal fatty chains that are optionally functionalized for the purposes of the invention are terminal chains linked to the last nitrogen atom of the polyamide backbone.

In particular, the ester groups of formula (B), which form part of the terminal and/or pendent fatty chains within the meaning of the invention, represent from 15% to 40% and better still from 20% to 35% of the total number of ester and amide groups.

Furthermore, m advantageously represents an integer ranging from 1 to 5 and better still greater than 2.

Preferably, Ri is a C12 to C22 and preferably C16 to C22 alkyl group. Advantageously, R₂ can be a C10 to C₄2 hydrocarbon-based (alkylene) group. Preferably, at least 50% and better still at least 75% of the groups R₂ are groups containing from 30 to 42 carbon atoms. The other groups R₂ are C₄ to C19 and better still C₄ to C12 hydrogen-containing groups.

Preferably, R₃ represents a C2 to C₃6 hydrocarbon-based group or a polyoxyalkylene group and R₄ represents a hydrogen atom. Preferably, R₃ represents a C2 to C12 hydrocarbon-based group.

The hydrocarbon-based groups may be linear, cyclic or branched, and saturated or unsaturated groups. Moreover, the alkyl and alkylene groups may be linear or branched, and saturated or unsaturated groups. In general, the polymers of formula (B) are in the form of mixtures of polymers, these mixtures also possibly containing a synthetic product corresponding to a compound of formula (B) in which n is 0, i.e. a diester.

According to one particularly preferred form of the invention, use will be made of a mixture of copolymers of a C₃6 diacid condensed onto ethylenediamine; the terminal ester groups result from the esterification of the remaining acid end groups with cetyl alcohol, stearyl alcohol or mixtures thereof (also known as cetylstearyl alcohol) (INCI name: Ethylenediamine/stearyl dimer dilinoleate copolymer). Its weight-average molecular mass is preferably 6000. These mixtures are especially sold by the company Arizona Chemical under the trade names Uniclear 80 and Uniclear 100 VG. They are sold, respectively, in the form of a gel at 80% (of active material) in a mineral oil, and at 100% (of active material). They have a softening point of 88°C to 94°C. As polyamide polycondensates corresponding to the general formula (A), mention may also be made of polymers comprising at least one terminal fatty chain bonded to the polymer backbone via at least one tertiary amide bonding group (also known as an amide-terminated polyamide or ATPA). For further information regarding these polymers, reference may be made to US 6 503 522.

According to one particularly preferred form of the invention, use will be made more particularly of a copolymer of hydrogenated linoleic diacid, of ethylenediamine and of di(C14-C18)alkylamine(s) (INCI name: Ethylenediamide/hydrogenated dimer dilinoleate copolymer bis-di-C14-C18 alkyl amide). This copolymer is especially sold under the trade name Sylvaclear A200V by the company Arizona Chemical.

According to another embodiment, the polyamide of formula (A) may also be an ester-terminated poly(ester-amide) (ETPEA), for instance those whose preparation is described in US 6 552 160.

According to one particularly preferred form of the invention, use will be made more particularly of a copolymer of hydrogenated linoleic diacid, of ethylenediamine and of neopentyl glycol and stearyl alcohol (INCI name: Bis- Stearyl Ethylenediamine/Neopentyl Glycol/Stearyl Hydrogenated Dimer Dilinoleate Copolymer). This copolymer is especially sold under the trade name Sylvaclear C75V by the company Arizona Chemical.

As polyamide polycondensates that may be used in the invention, mention may also be made of those comprising at least one terminal fatty chain bonded to the polymer backbone via at least one ether or polyether bonding group (it is then referred to as an ether-terminated poly(ether)amide). Such polymers are described, for example, in US 6 399 713. The polyamide in accordance with the invention advantageously has a softening point of greater than 65°C, which may be up to 190°C. It preferably has a softening point ranging from 70°C to 130°C and better still from 80°C to 105°C. The polyamide is in particular a non-waxy polymer. As polyamide polycondensates that may be used in the invention, mention may also be made of polyamide resins resulting from the condensation of an aliphatic dicarboxylic acid and a diamine (including compounds containing more than 2 carbonyl groups and 2 amine groups), the carbonyl and amine groups of adjacent individual units being condensed via an amide bond. These polyamide resins are especially the products sold under the brand name Versamid® by the companies General Mills, Inc. and Henkel Corp. (Versamid 930, 744 or 1655) or by the company Olin Mathieson Chemical Corp., under the brand name Onamid® especially Onamid S or C. These resins have a weight-average molecular mass ranging from 6000 to 9000. For further information regarding these polyamides, reference may be made to US 3 645 705 and US 3 148 125. Use is made more especially of Versamid® 930 or 744.

It is also possible to use the polyamides sold by the company Arizona Chemical under the references Uni-Rez (2658, 2931 , 2970, 2621 , 2613, 2624, 2665, 1554, 2623 and 2662) and the product sold under the reference Macromelt 6212 by the company Henkel. For further information regarding these polyamides, reference may be made to US 5 500 209. It is also possible to use vegetable-based polyamide resins, for instance those described in patents US 5 783 657 and US 5 998 570.

VOLATILE ALKANES The compositions of the invention comprise at least one linear or branched volatile alkane.

The term "volatile alkane" that is suitable for use in the invention means a cosmetic alkane, which is capable of evaporating on contact with the skin in less than one hour, at room temperature (25°C) and atmospheric pressure (760 mmHg, i.e. 101 325 Pa), which is liquid at room temperature, especially having an evaporation rate ranging from 0.01 to 15 mg/cm²/minute, at room temperature (25°C) and atmospheric pressure (760 mmHg). Preferably, the "volatile alkanes" that are suitable for use in the invention have an evaporation rate ranging from 0.01 to 3.5 mg/cm²/minute, at room temperature (25°C) and atmospheric pressure (760 mmHg).

Preferably, the "volatile alkanes" that are suitable for use in the invention have an evaporation rate ranging from 0.01 to 1 .5 mg/cm²/minute, at room temperature (25°C) and atmospheric pressure (760 mmHg).

More preferably, the "volatile alkanes" that are suitable for use in the invention have an evaporation rate ranging from 0.01 to 0.8 mg/cm²/minute, at room temperature (25°C) and atmospheric pressure (760 mmHg).

Also preferably, the "volatile alkanes" that are suitable for use in the invention have an evaporation rate ranging from 0.01 to 0.3 mg/cm²/minute, at room temperature (25°C) and atmospheric pressure (760 mmHg).

Also preferably, the "volatile alkanes" that are suitable for use in the invention have an evaporation rate ranging from 0.01 to 0.12 mg/cm²/minute, at room temperature (25°C) and atmospheric pressure (760 mmHg). The evaporation rate of a volatile alkane in accordance with the invention (and more generally of a volatile solvent) may especially be evaluated by means of the protocol described in WO 06/013 413, and more particularly by means of the protocol described below. 15 g of volatile hydrocarbon-based solvent are placed in a crystallizing dish (diameter: 7 cm) placed on a balance that is in a chamber of about 0.3 m³ with regulated temperature (25°C) and hygrometry (50% relative humidity). The liquid is allowed to evaporate freely, without stirring, while providing ventilation by means of a ventilator (Papst-Motoren, reference 8550 N, rotating at 2700 rpm) placed vertically above the crystallizing dish containing the volatile hydrocarbon-based solvent, the blades being directed towards the crystallizing dish, 20 cm away from the bottom of the crystallizing dish.

The mass of volatile hydrocarbon-based solvent remaining in the crystallizing dish is measured at regular time intervals.

The evaporation profile of the solvent is then obtained by plotting the curve of the amount of product evaporated (in mg/cm²) as a function of time (in minutes). The evaporation rate is then calculated, which corresponds to the tangent to the origin of the curve obtained. The evaporation rates are expressed in mg of volatile solvent evaporated per unit area (cm²) and per unit of time (minutes). According to one preferred embodiment, the "volatile alkanes" that are suitable for use in the invention have a non-zero vapour pressure (also known as the saturating vapour pressure), at room temperature, in particular a vapour pressure ranging from 0.3 Pa to 6000 Pa. Preferably, the "volatile alkanes" that are suitable for use in the invention have a vapour pressure ranging from 0.3 to 2000 Pa, at room temperature (25°C).

Preferably, the "volatile alkanes" that are suitable for use in the invention have a vapour pressure ranging from 0.3 to 1000 Pa, at room temperature (25°C).

More preferably, the "volatile linear alkanes" that are suitable for use in the invention have a vapour pressure ranging from 0.4 to 600 Pa, at room temperature (25°C). Preferably, the "volatile alkanes" that are suitable for use in the invention have a vapour pressure ranging from 1 to 200 Pa, at room temperature (25°C).

Also preferably, the "volatile alkanes" that are suitable for use in the invention have a vapour pressure ranging from 3 to 60 Pa, at room temperature (25°C).

According to one embodiment, a volatile linear alkane that is suitable for use in the invention may have a flash point that is in the range from 30 to 120°C and more particularly from 40 to 100°C. The flash point is in particular measured according to standard ISO 3679. a) Volatile branched alkanes

Among the branched volatile alkanes, mention may be made of branched C8-C16 alkanes, for instance C8-C16 isoalkanes of petroleum origin (also known as isoparaffins), for instance isododecane (also known as 2,2,4,4,6- pentamethylheptane), isodecane and isohexadecane; the oils sold under the trade name Isopar or Permethyl. Isododecane will preferably be used. b) Volatile linear alkanes

The volatile linear alkanes that are suitable for use in the invention are preferably chosen from volatile linear alkanes comprising from 7 to 14 carbon atoms.

Preferably, the "volatile linear alkanes" that are suitable for use in the invention comprise from 8 to 14 carbon atoms.

Preferably, the "volatile linear alkanes" that are suitable for use in the invention comprise from 9 to 14 carbon atoms. Preferably, the "volatile linear alkanes" that are suitable for use in the invention comprise from 1 0 to 14 carbon atoms.

Preferably, the "volatile linear alkanes" that are suitable for use in the invention comprise from 1 1 to 14 carbon atoms.

According to one advantageous embodiment, the "volatile linear alkanes" that are suitable for use in the invention have an evaporation rate, as defined above, ranging from 0.01 to 3.5 mg/cm²/minute, at room temperature (25°C) and atmospheric pressure (760 mmHg), and comprise from 8 to 14 carbon atoms.

A volatile linear alkane that is suitable for use in the invention may advantageously be of plant origin.

Preferably, the volatile linear alkane or the mixture of volatile linear alkanes present in the composition according to the invention comprises at least one ¹ C carbon-14) carbon isotope. In particular, the ¹ C isotope may be present in a C/¹²C ratio of greater than or equal to 1 * 1 0^"16, preferably greater than or equal to 1 * 1 0^"15, more preferably greater than or equal to 7.5* 1 0^"14 and better still greater than or equal to 1 .5* 1 0^"13 Preferably, the ratio ¹ C/¹²C ranges from 6x 1 0^" ¹³ to 1 .2x 1 0^"12

The amount of ¹ C isotopes in the volatile linear alkane or the mixture of volatile linear alkanes may be determined via methods known to those skilled in the art such as the Libby compacting method, liquid scintillation spectrometry or accelerator mass spectrometry.

Such an alkane may be obtained, directly or in several steps, from a plant raw material, such as an oil, a butter, a wax, etc. As examples of alkanes that are suitable for use in the invention, mention may be made of the alkanes described in patents WO 2007/068 371 or WO 2008/1 55 059 of the company Cognis (mixtures of different alkanes differing by at least one carbon). These alkanes are obtained from fatty alcohols, which are themselves obtained from coconut oil or palm oil. As examples of linear alkanes that are suitable for use in the invention, mention may be made of n-heptane (C₇), n-octane (Ce), n-nonane (Cg), n-decane (C-io), n- undecane (Cn ), n-dodecane (C12), n-tridecane (C13) and n-tetradecane (Cu), and mixtures thereof. According to one particular embodiment, the volatile linear alkane is chosen from n-nonane, n-undecane, n-dodecane, n-tridecane and n- tetradecane, and mixtures thereof.

According to one preferred mode, mention may be made of mixtures of n- undecane (Cu) and of n-tridecane (C13) obtained in Examples 1 and 2 of patent application WO 2008/155 059 of the company Cognis.

Mention may also be made of n-dodecane (C12) and n-tetradecane (Cu) sold by Sasol under the respective references Parafol 12-97 and Parafol 14-97, and also mixtures thereof.

The volatile linear alkane may also be used alone.

Alternatively or preferentially, a mixture of two different volatile liquid linear alkanes, differing from each other by a carbon number n of at least 1 , in particular differing from each other by a carbon number of 1 or 2, may be used.

According to a first embodiment, a mixture of at least two different volatile linear alkanes comprising from 10 to 14 carbon atoms and differing from each other by a carbon number of at least 1 may be used. Examples that may especially be mentioned include mixtures of volatile linear do/Cn , C11/C12, or C12/C13 alkanes.

According to another embodiment, a mixture of at least two different volatile linear alkanes comprising from 10 to 14 carbon atoms and differing from each other by a carbon number of at least 2 may be used. By way of example, mention may be made especially of mixtures of volatile linear C10/C12 or C12 C14 alkanes, for an even carbon number n, and the C11/C13 mixture for an odd carbon number n.

According to one preferred mode, a mixture of at least two different volatile linear alkanes comprising from 10 to 14 carbon atoms and differing from each other by a carbon number of at least 2, and in particular a mixture of C11/C13 volatile linear alkanes or a mixture of C12/C14 volatile linear alkanes, is used.

Other mixtures combining more than two volatile linear alkanes according to the invention, for instance a mixture of at least three different volatile linear alkanes comprising from 7 to 14 carbon atoms and differing from each other by a carbon number of at least 1 , also form part of the invention, but mixtures of two volatile linear alkanes according to the invention are preferred (binary mixtures), the said two volatile linear alkanes preferably representing more than 95% and better still more than 99% by weight of the total content of volatile linear alkanes in the mixture. According to one particular mode of the invention, in a mixture of volatile linear alkanes, the volatile linear alkane having the smaller carbon number is predominant in the mixture. According to another mode of the invention, a mixture of volatile linear alkanes in which the volatile linear alkane having the larger carbon number is predominant in the mixture is used. As examples of mixtures that are suitable for use in the invention, mention may be made especially of the following mixtures:

- from 50% to 90% by weight, preferably from 55% to 80% by weight and more preferentially from 60% to 75% by weight of C_n liquid volatile linear alkane with n ranging from 7 to 14,

- from 10% to 50% by weight, preferably from 20% to 45% by weight and preferably from 24% to 40% by weight of C_n+X liquid volatile linear alkane with x greater than or equal to 1 , preferably x = 1 or x = 2, with n+x between 10 and 14, relative to the total weight of alkanes in the said mixture.

In particular, the said mixture of alkanes according to the invention contains:

- less than 2% by weight and preferably less than 1 % by weight of branched hydrocarbons,

- and/or less than 2% by weight and preferably less than 1 % by weight of aromatic hydrocarbons,

- and/or less than 2% by weight, preferably less than 1 % by weight and preferentially less than 0.1 % by weight of unsaturated hydrocarbons in the mixture.

More particularly, a volatile linear alkane that is suitable for use in the invention may be used in the form of an n-undecane/n-tridecane mixture. In particular, use will be made of a mixture of volatile linear alkanes comprising:

- from 55% to 80% by weight and preferably from 60% to 75% by weight of Cn liquid volatile linear alkane (n-undecane),

- from 20% to 45% by weight and preferably from 24% to 40% by weight of C13 liquid volatile linear alkane (n-tridecane),

relative to the total weight of alkanes in the said mixture.

According to one particular embodiment, the mixture of alkanes is an n- undecane/n-tridecane mixture. In particular, such a mixture may be obtained according to Example 1 or Example 2 of WO 2008/155 059.

According to another embodiment, the n-dodecane sold under the reference Parafol 12-97 by Sasol is used.

According to another embodiment, the n-dodecane sold under the reference Parafol 14-97 by Sasol is used.

According to yet another embodiment, a mixture of n-dodecane and n-tetradecane is used. According to another particular embodiment, an n-dodecane/n-tetradecane mixture (C12/C14) is used, comprising:

a) from 65% to 95% by weight and preferably from 70% to 90% by weight of C12 liquid volatile linear alkane (n-dodecane) and b) from 5% to 35% by weight and preferably from 10% to 30% by weight of Cu volatile liquid linear alkane (n-tetradecane) relative to the total weight of alkanes in the said mixture. Among the linear or branched volatile alkanes, volatile linear alkanes such as those indicated previously will preferably be chosen, and more particularly the n- undecane/n-tridecane mixtures as described previously.

The volatile alkane(s) in accordance with the invention are preferably present in contents ranging from 1 % to 60% by weight and preferably from 5% to 40% by weight relative to the total weight of the composition.

Additional oils

The compositions in accordance with the invention may also contain one or more non-volatile or volatile oils chosen from hydrocarbon-based oils and silicone oils, or mixtures thereof.

The term "non-volatile oil" means an oil that remains on the skin or the keratin fibre 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).

As other non-volatile hydrocarbon-based oils that may be used according to the invention, mention may be made especially of:

(i) hydrocarbon-based oils of plant origin, such as glyceride triesters, which are generally triglycerides consisting of fatty acid esters of glycerol, the fatty acids of which may have varied chain lengths from C4 to C24, these chains possibly being linear or branched, and saturated or unsaturated; these oils are especially wheatgerm oil, sunflower oil, grapeseed oil, sesame seed oil, corn oil, apricot oil, castor oil, shea oil, avocado oil, olive oil, soybean oil, sweet almond oil, palm oil, rapeseed oil, cottonseed oil, hazelnut oil, macadamia oil, jojoba oil, alfalfa oil, poppy oil, pumpkin oil, sesame seed oil, marrow oil, rapeseed oil, blackcurrant oil, evening primrose oil, millet oil, barley oil, quinoa oil, rye oil, safflower oil, candlenut oil, passion flower oil and musk rose oil; or alternatively caprylic/capric acid 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,

(ii) synthetic ethers containing from 10 to 40 carbon atoms;

(iii) linear or branched hydrocarbons of mineral or synthetic origin, such as petroleum jelly, polydecenes, hydrogenated polyisobutene such as Parleam, and squalane, and mixtures thereof;

(iv) synthetic esters, for instance the oils of formula RCOOR' in which R represents a linear or branched fatty acid residue comprising from 1 to 40 carbon atoms and R' represents a hydrocarbon-based chain that is especially branched, containing from 1 to 40 carbon atoms, on condition that R + R' > 10, for instance purcellin oil (cetostearyl octanoate), isopropyl myristate, isopropyl palmitate, C12- C-I5 alkyl benzoate, for instance the product sold under the trade name Finsolv TN or Witconol TN by the company Witco or Tegosoft TN by the company Evonik Goldschmidt, 2-ethyl phenyl benzoate, for instance the commercial product sold under the name X-Tend 226 by the company ISP, isopropyl lanolate, hexyl laurate, diisopropyl adipate, isononyl isononanoate, oleyl erucate, 2-ethylhexyl palmitate, isostearyl isostearate, alcohol or polyalcohol octanoates, decanoates or ricinoleates, for instance propylene glycol dioctanoate; hydroxylated esters, for instance isostearyl lactate, diisostearyl malate; and pentaerythritol esters; citrates or tartrates, for instance linear C12-C13 dialkyl tartrates, such as those sold under the name Cosmacol ETI by the company Enichem Augusta Industriale, and also linear C14-C15 dialkyl tartrates such as those sold under the name Cosmacol ETL by the same company; acetates; (v) fatty alcohols that are liquid at room temperature, containing a branched and/or unsaturated carbon-based chain containing from 12 to 26 carbon atoms, for instance octyldodecanol, isostearyl alcohol, oleyl alcohol, 2-hexyldecanol, 2- butyloctanol or 2-undecylpentadecanol;

(vi) higher fatty acids such as oleic acid, linoleic acid or linolenic acid;

(vii) carbonates such as dicaprylyl carbonate, for instance the product sold under the name Cetiol CC by the company Cognis;

(viii) fatty amides, for instance isopropyl N-lauroyl sarcosinate, for instance the product sold under the trade name Eldew SL205 from Ajinomoto;

and mixtures thereof. Among the additional non-volatile hydrocarbon-based oils that may be used according to the invention, glyceride triesters will more particularly preferred, and especially caprylic/capric acid triglycerides, synthetic esters and especially isononyl isononanoate, oleyl erucate and C12-C15 alcohol benzoates, and fatty alcohols, especially octyldodecanol.

The additional volatile hydrocarbon-based oils may be chosen from C8-C16 branched esters, for instance isohexyl neopentanoate, and mixtures thereof; petroleum distillates, especially those sold under the name Shell Solt by the company Shell, may also be used.

The non-volatile silicone oils may be chosen especially from non-volatile polydimethylsiloxanes (PDMSs), polydimethylsiloxanes comprising alkyl or alkoxy groups, that are pendent and/or at the end of a silicone chain, the groups each containing from 2 to 24 carbon atoms, phenyl silicones, for instance phenyl trimethicones, phenyl dimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyl dimethicones, diphenylmethyldiphenyltrisiloxanes and 2-phenylethyl trimethylsiloxysilicates.

Volatile silicone oils that may be mentioned, for example, include volatile linear or cyclic silicone oils, especially those with a viscosity < 8 centistokes (8x10^"6 m²/s) and especially containing from 2 to 7 silicon atoms, these silicones optionally comprising alkyl or alkoxy groups containing from 1 to 10 carbon atoms. As volatile silicone oils that may be used in the invention, mention may be made especially of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, heptamethylhexyltrisiloxane, heptamethyloctyltrisiloxane, hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane and dodecamethylpentasiloxane, and mixtures thereof.

Mention may also be made of linear volatile alkyltrisiloxane oils of general formula (I):

in which R represents an alkyl group containing from 2 to 4 carbon atoms, of which one or more hydrogen atoms may be substituted with a fluorine or chlorine atom.

Among the oils of general formula (I) that may be mentioned are:

3-butyl-1 , 1 , 1 ,3,5,5,5-heptamethyltrisiloxane,

3-propyl-1 , 1 , 1 ,3,5,5,5-heptamethyltrisiloxane, and

3-ethyl-1 , 1 , 1 ,3,5,5,5-heptamethyltrisiloxane,

corresponding to the oils of formula (I) for which R is, respectively, a butyl group, a propyl group or an ethyl group.

LIPOPHILIC ORGANIC UV-SCREENING AGENTS They may be chosen especially from para-am inobenzoic acid derivatives, salicylic derivatives, cinnamic derivatives, benzophenones and aminobenzophenones, anthranilic derivatives, dibenzoylmethane derivatives, β,β-diphenylacrylate derivatives, benzylidenecamphor derivatives, phenylbenzimidazole derivatives, benzotriazole derivatives, triazine derivatives, bis-resorcinyl triazines, imidazoline derivatives, benzalmalonate derivatives, 4,4-diarylbutadiene derivatives, benzoxazole derivatives and merocyanins, and mixtures thereof.

Among the lipophilic organic UVA screening agents that are capable of absorbing UV from 320 to 400 nm, mention may be made of

Dibenzoylmethane derivatives:

- 4-isopropyldibenzoylmethane, sold under the name Eusolex 8020 by the company Merck, and corresponding to the following formula:

- 1 -(4-methoxy-1 -benzofuran-5-yl)-3-phenylpropane-1 ,3-dione, provided for sale by the company Quest under the name of Pongamol, of formula:

-butylphenyl)-3-(2-hydroxyphenyl)propane-1 ,3-dione of formula:

- butylmethoxydibenzoylmethane, sold especially under the trade name Parsol 1789 by Hoffmann LaRoche,

Aminobenzophenones:

n-hexyl 2-(4-diethylamino-2-hydroxybenzoyl)benzoate sold under the trade name Uvinul A+ or in the form of a mixture with octyl methoxycinnamate under the trade name Uvinul A + B by BASF,

Anthranilic derivatives:

Menthyl anthranilate sold under the trade name Neo Heliopan MA by Haarmann & Reimer,

4.4-Diarylbutadiene derivatives:

1 , 1 -dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene. The preferential compounds are:

Butylmethoxydibenzoylmethane,

n-Hexyl 2-(4-diethylamino-2-hydroxybenzoyl)benzoate.

Among the lipophilic organic UVB screening agents that are capable of absorbing UV from 280 to 320 nm, mention may be made of para-Am inobenzoates:

Ethyl PABA,

Ethyl dihydroxypropyl PABA,

Ethylhexyl Dimethyl PABA (Escalol 507 from ISP),

Salicylic derivatives:

- Homosalate sold under the name Eusolex HMS by Rona/EM Industries,

- Ethylhexyl salicylate sold under the name Neo Heliopan OS by Haarmann & Reimer,

- Dipropylene glycol salicylate sold under the name Dipsal by Scher,

TEA salicylate sold under the name Neo Heliopan TS by Haarmann & Reimer, Cinnamates:

Ethylhexyl methoxycinnamate sold in particular under the trade name Parsol MCX by Hoffmann LaRoche,

Isopropyl methoxycinnamate,

Isoamyl methoxycinnamate sold under the trade name Neo Heliopan E 1000 by Haarmann & Reimer,

Diisopropyl methylcinnamate, Cinoxate,

Glyceryl ethylhexanoate dimethoxycinnamate, β,β'-Diphenylacrylate derivatives:

Octocrylene sold especially under the trade name Uvinul N539 by BASF,

Etocrylene sold especially under the trade name Uvinul N35 by BASF,

Benzylidenecamphor derivatives:

3-Benzylidenecamphor manufactured under the name Mexoryl SD by Chimex, Methylbenzylidenecamphor sold under the name Eusolex 6300 by Merck,

Polyacrylamidomethylbenzylidenecamphor manufactured under the name Mexoryl SW by Chimex,

Triazine derivatives:

- ethylhexyltriazone sold in particular under the trade name Uvinul T150 by BASF,

- diethylhexylbutamidotriazone sold under the trade name Uvasorb HEB by Sigma 3V,

- 2,4,6-tris(dineopentyl 4'-aminobenzalmalonate)-s-triazine,

- 2,4,6-tris(diisobutyl 4'-aminobenzalmalonate)-s-triazine,

- 2,4-bis(dineopentyl 4'-aminobenzalmalonate)-6-(n-butyl 4'-aminobenzoate)-s- triazine,

- 2,4-bis(n-butyl 4'-aminobenzoate)-6-(aminopropyltrisiloxane)-s-triazine,

Imidazoline derivatives:

Ethylhexyldimethoxybenzylidenedioxoimidazoline propionate,

Benzalmalonate derivatives:

Polyorganosiloxanes containing benzalmalonate functions, for instance Polysilicone-15, sold under the trade name Parsol SLX by Hoffmann LaRoche Dineopentyl 4'-methoxybenzalmalonate,

Merocvanin derivatives:

Octyl 5-N,N-diethylamino-2-phenylsulfonyl-2,4-pentadienoate. The preferential compounds are:

Homosalate,

Ethylhexyl salicylate,

Ethylhexyl methoxycinnamate,

Octocrylene,

Ethylhexyl triazone,

2,4-Bis(n-butyl 4'-aminobenzoate)-6-(aminopropyltrisiloxane)-s-triazine,

Octyl 5-N,N-diethylamino-2-phenylsulfonyl-2,4-pentadienoate.

Among the broad-spectrum lipophilic organic screening agents capable of absorbing UVA and UVB, mention may be made of:

Benzophenone derivatives:

Benzophenone-1 sold under the trade name Uvinul 400 by BASF,

Benzophenone-2 sold under the trade name Uvinul D50 by BASF,

Benzophenone-3 or oxybenzone sold under the trade name Uvinul M40 by BASF, Benzophenone-5,

Benzophenone-6 sold under the trade name Helisorb 1 1 by Norquay,

Benzophenone-8 sold under the trade name Spectra-Sorb UV-24 by American Cyanamid,

Benzophenone-10,

Benzophenone-1 1 ,

Benzophenone-12,

Benzotriazole derivatives:

Drometrizole trisiloxane sold under the name Silatrizole by Rhodia Chimie, Bumetrizole sold under the name Tinoguard AS by Ciba-Geigy,

Bis-resorcinyl triazine derivatives:

Bis(ethylhexyloxyphenol)methoxyphenyltriazine sold under the trade name Tinosorb S by Ciba-Geigy,

Benzoxazole derivatives:

2,4-bis[5-(1 -dimethylpropyl)benzoxazol-2-yl(4-phenyl)imino]-6-(2-ethylhexyl)imino- 1 ,3,5-triazine sold under the name Uvasorb K2A by Sigma 3V.

The preferential compounds are:

Benzophenone-3,

Drometrizole trisiloxane,

Bis(ethylhexyloxyphenol)methoxyphenyltriazine.

The lipophilic organic screening agents are generally present in the compositions according to the invention in proportions ranging from 0.1 % to 50% by weight relative to the total weight of the composition, and preferably ranging from 2% to 30% by weight relative to the total weight of the composition.

According to one particularly preferred form of the invention, the compositions will be transparent and will preferably have a turbidity of less than 1000 NTU (nephelometric turbidity units) at 25°C, preferably less than 50 NTU at 25°C and even more preferentially less than 15 NTU, measured using a 21 OOP turbidimeter machine from the company Hach. (to be confirmed)

According to one particularly preferred form of the invention, the compositions will have an SPF of greater than 10, or even greater than 15 or even greater than 20. According to one particularly preferred form of the invention, the compositions will have a UVAp_PD PF of greater than 5, and they also satisfy the recommendation for the regulation, especially the European regulation, which stipulates that the SPF/PPD ratio should be less than 3. ADDITIVES

The oily composition of the product of the invention may also contain various additives that may be soluble in the oily phase, or that may be in dispersion in the said oily phase, chosen especially from lipophilic dyes, lipophilic active agents, lipophilic polymers other than the polyamide polycondensates of the invention, organic solvents, preserving agents, insect repellents, essential oils, fragrances, emollients and propellants.

Among the lipophilic cosmetic active agents, examples that may be mentioned include antioxidants, keratolytic agents such as N-alkylsalicylic acids, for example N-octanoyl-5-salicylic acid; vitamins, for instance vitamin E (tocopherol and derivatives), vitamin A (retinol and derivatives); softeners and any lipophilic active agent usually used for caring for the skin or the hair. Additional lipophilic polymers that may be mentioned include styrene-based block copolymers such as styrene/ethylene-butylene/styrene copolymer such as the product sold under the name Kraton G-1650E by the company Kraton Polymers; acrylic or methacrylic acid copolymers, such as the acrylate/stearyl acrylate/dimethicone methacrylate copolymer sold under the name KP 561 P by the company Shin-Etsu; poly-Cio-C3o-alkyl acrylates, for instance the product sold under the name Intelimer IPA 13-1 by the company Landec.

Needless to say, a person skilled in the art will take care to select the optional additional compound(s) mentioned above and/or the amounts thereof such that the advantageous properties intrinsically associated with the compositions in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition(s).

Another subject of the present invention consists of the use of the compositions according to the invention as defined above for the manufacture of cosmetic products for treating the skin, the nails, the hair, the eyelashes, the eyebrows and/or the scalp, especially care products and antisun products.

The cosmetic compositions according to the invention may be used, for example, as daily antisun and/or photoprotective care and/or sun protection products and/or makeup products and/or hair products, for the face and/or the body and/or the hair, of liquid consistency.

FRAGRANCES

According to one particular form of the invention, the cosmetic compositions according to the invention may constitute fragrancing products and may also contain a fragrancing substance. The term "fragrancing product" means any composition that leaves a fragrance after application to keratin materials.

The term "fragrancing substance" means any fragrance or aroma capable of fragrancing the skin and human keratin materials in general comprising the skin, the hair, the scalp, the lips and the nails.

Fragrances and aromas of natural or synthetic origin and mixtures thereof may be used in the composition of the invention as fragrancing substance. As fragrances and aromas of natural origin, mention may be made, for example, of extracts from flowers (lily, lavender, rose, jasmine, ylang ylang), from stems and leaves (patchouli, geranium, petitgrain), from fruit (coriander, aniseed, cumin, juniper), from fruit peel (bergamot, lemon, orange), from roots (angelica, celery, cardamom, iris, rattan palm), from wood (pinewood, sandalwood, gaiac wood, rose of cedar), from grasses and gramineae (tarragon, lemongrass, sage, thyme), from needles and branches (spruce, fir, pine, dwarf pine) and from resins and balms (galbanum, elemi, benjoin, myrrh, olibanum, opopanax).

As fragrancing substances of synthetic origin, examples that may be mentioned include compounds of the ester, ether, aldehyde, ketone, aromatic alcohol and hydrocarbon type.

Esters that may be mentioned in particular include benzyl acetate, benzyl benzoate, phenoxyethyl isobutyrate, p-tert-butylcyclohexyl acetate, citronellyl acetate, citronellyl formate, geranyl acetate, linalyl acetate, dimethylbenzylcarbinyl acetate, phenylethyl acetate, linalyl benzoate, benzyl formate, ethylmethylphenyl glycinate, alkylcyclohexyl propionate, styrallyl propionate and benzyl salicylate.

An ether that may be mentioned is benzyl ethyl ether. Examples of aldehydes that may be mentioned include linear alkanals comprising from 8 to 18 carbon atoms, citral, citronellal, citronellyloxyacetaldehyde, cyclamenaldehyde, hydroxycitronellal, lilial and bourgeonal.

Examples of ketones that may be mentioned include ionones, for instance alpha- isomethylionone and methyl cedryl ketone.

Among the aromatic and especially terpenic alcohols, mention may be made of anethole, citronellol, eugenol, isoeugenol, geraniol, linalool, phenylethyl alcohol and terpineol.

Hydrocarbons that may especially be mentioned are terpenes. These compounds are often in the form of a mixture of two or more of these odoriferous substances.

Moreover, it is also possible to use essential oils, aroma components, for instance essences of sage, camomile, clove, balm, mint, cinnamon leaves, lime tree blossom, juniper, vetiver, olibanum, galbanum, labolanum and lavandin.

Essence of bergamot, dihydromyrcenol, lilial, lyral, citronellol, phenylethyl alcohol, alpha-hexylcinnamaldehyde, geraniol, benzylacetone, cyclamenaldehyde, linalool, ambroxane, indol, hedione, sandelice, essences of lemon, mandarin and orange, allylamine glycolate, cyclovertal, essence of lavandin, essence of sage, beta- damascone, essence of geranium, cyclohexyl salicylate, phenylacetic acid, geranyl acetate, benzyl acetate and rose oxide may be used as fragrancing substance, alone or as a mixture.

It is also possible to use a mixture of different fragrancing substances that generate a common note that is pleasant to the user. Among the known olfactory notes, mention may be made, for example, of citrus fragrances, aromatics, floral fragrances, musks, fruity and spicy fragrances, oriental fragrances, marine fragrances, aquatic notes, chypre fragrances, woody and fern fragrances, and mixtures thereof.

The amount of fragrancing substance(s) will preferably be from 5% to 25% by weight and better still from 10 to 20% by weight relative to the total weight of the composition.

ADDITIONAL COLOURING AGENTS According to another particular form of the invention, the compositions of the invention may also comprise one or more additional colouring agents.

The additional colouring agents may also be chosen from natural and synthetic direct dyes. They may be organic or mineral dyes.

The natural or synthetic liposoluble organic dyes are, for example, DC Red 17, DC Red 21 , DC Red 27, DC Green 6, DC Yellow 1 1 , DC Violet 2, DC Orange 5, Sudan red, carotenes (β-carotene or lycopene), xanthophylls (capsanthin, capsorubin or lutein), palm oil, Sudan brown, quinoline yellow, annatto and curcumin.

The additional colouring agents may also be chosen from particulate dyestuffs, which are preferably chosen from pigments, nacres or interference pigments, and glitter flakes.

The term "pigments" should be understood as meaning white or coloured, mineral or organic particles of any form, which are insoluble in the physiological medium and are intended to colour the composition. The pigments may be white or coloured, and mineral and/or organic. Among the mineral pigments that may be mentioned are titanium dioxide, optionally surface- treated, zirconium oxide or cerium oxide, and also zinc oxide, iron (black, yellow or red) oxide or chromium oxide, manganese violet, ultramarine blue, chromium hydrate and ferric blue, and metal powders, for instance aluminium powder and copper powder.

Among the organic pigments that may be mentioned are carbon black, pigments of D&C type and lakes based on cochineal carmine or on barium, strontium, calcium or aluminium.

Mention may also be made of pigments with an effect, such as particles comprising a natural or synthetic, organic or mineral substrate, for example glass, acrylic resins, polyester, polyurethane, polyethylene terephthalate, ceramics or aluminas, the said substrate optionally being coated with metallic substances such as aluminium, gold, silver, platinum, copper or bronze, or metal oxides such as titanium dioxide, iron oxide or chromium oxide, and mixtures thereof.

For the purposes of the present invention, the term "interference particles or nacres" denotes any particle generally having a multilayer structure such that it allows the creation of a colour effect by interference of light rays, which diffract and scatter differently according to the nature of the layers. The colouring effects obtained are associated with the lamellar structure of these particles and are derived from the physical laws of thin film optics (see: Pearl lustre pigments - physical principles, properties, applications - R. Maisch, M. Weigand. Verlag Moderne Industrie). Thus, these particles may have colours that vary according to the angle of observation and the incidence of the light.

For the purposes of the present invention, a multilayer structure is intended to denote, without preference, a structure formed from a substrate coated with a single layer, or a structure formed from a substrate coated with at least two or even more consecutive layers.

The multilayer structure may thus comprise one or even at least two layers, each layer, independently or otherwise of the other layer(s), being made of at least one material chosen from the group consisting of the following materials: MgF₂, CeF₃, ZnS, ZnSe, Si, Si0₂, Ge, Te, Fe₂0₃, Pt, Va, Al₂0₃, MgO, Y₂0₃, S₂0₃, SiO, Hf0₂, Zr0₂, Ce0₂, Nb₂0₅, Ta₂0₅, Ti0₂, Ag, Al, Au, Cu, Rb, Ti, Ta, W, Zn, MoS₂, cryolite, alloys and polymers, and combinations thereof. Generally, the multilayer structure is of mineral nature.

More particularly, the interference particles under consideration according to the invention may be interference pigments, or alternatively natural or synthetic, monolayer or multilayer nacres, in particular formed from a natural substrate based, inter alia, on mica, which is covered with one or more layers of metal oxide.

The interference particles according to the invention are characterized in that 50% of the mass population has a diameter (d50) of less than 40 pm, more particularly less than 30 pm, especially less than 20 pm and in particular less than 15 pm, measured with a laser granulometer, for instance the Mastersizer 2000® machine from Malvern or the BI90+® machine from Brookhaven Instrument Corporation.

Nacres of mica/tin oxide/titanium oxide type, for instance those sold under the names Timiron Silk Blue®, Timiron Silk Red®, Timiron Silk Green®, Timiron Silk Gold® and Timiron Super Silk® sold by the company Merck, and mica/iron oxide/titanium oxide nacres, for instance Flamenco Satin Blue®, Flamenco Satin Red® and Flamenco Satin Violet® and Flamenco Orange 320C sold by the company Engelhard, and mixtures thereof, are most particularly suitable for the invention.

More specifically, these pigments may be present in amounts ranging from 0.01 % to 10% by weight and preferably ranging from 0.1 % to 5% by weight relative to the total weight of the composition.

VAPORIZABLE COMPOSITIONS

The compositions according to the invention may be in the form of a vaporizable oil applied to the skin or the hair in the form of fine particles by means of pressurization devices. The devices in accordance with the invention are well known to those skilled in the art and comprise non-aerosol pumps or "atomizers", aerosol containers comprising a propellant and also aerosol pumps using compressed air as propellant. These devices are described in patents US 4 077 441 and US 4 850 517 (which form an integral part of the content of the description).

These compositions may also be impregnated onto supports such as wipes, or they may be conditioned as lotions in a bottle with a reducing agent. The compositions conditioned in aerosol form in accordance with the invention generally contain conventional propellants, for instance hydrofluoro compounds, dichlorodifluoromethane, difluoroethane, dimethyl ether, isobutane, n-butane, propane or trichlorofluoromethane. They are preferably present in amounts ranging from 15% to 50% by weight relative to the total weight of the composition.

According to one particularly preferred form of the invention, the compositions will have an SPF of greater than 10, or even greater than 15 and even greater than 20.

According to one particularly preferred form of the invention, the compositions will have a UVAp_PD PF of greater than 5, and they also satisfy the recommendation for the regulation, especially the European regulation, which stipulates that the SPF/PPD should be less than 3.

Concrete, but in no way limiting, examples illustrating the invention will now be given. The amounts of the constituents are expressed as weight percentages relative to the total weight of the composition. EXAMPLES

Each composition is prepared by mixing together the starting materials and heating to 90-95°C with stirring until the starting materials have fully dissolved. The mixture is cooled to 25°C with stirring.

The following are evaluated for each of the compositions:

(i) the viscosity after 24 hours, measured using a Rheomat 180 viscometer at 25°C, the spin speed at 200 rpm after 30 seconds of rotation,

(ii) the transparency of the formulations, with a 21 OOP turbidimeter machine from the company Hach,

(iii) the appearance of the formulation at 24 hours,

(iv) the stability at 2 months, at 4, 25 and 45°C,

(v) the in vivo SPF on 5 individuals, according to the international method published by Colipa / CTFA SA / JCIA (May 2006). EXAMPLES 1 TO 3:

(^*) outside the invention

Table 1

Examples 2 and 3 of alcohol-free antisun oil according to the invention are stable after storage for 2 months at various temperatures (4, 25 and 45°C). They also have the advantage of being vaporizable and cosmetically pleasant. Examples 4 and 5:

Ingredients Ex. 4 Ex. 5

Plant oils 50 50

Isododecane 14.75 -

Undecane/tridecane mixture according to example - 14.75

1 or example 2 of document

WO 2008/155 059

C-12-C-1 5 alkyl benzoate 10 10

(Tegosoft TN from Evonik Goldschmidt)

Ethylenediamine/stearyl dimer dilinoleate 6 6 copolymer (Uniclear 100 VG - Arizona Chemical)

Butylmethoxydibenzoylmethane 4 4

Ethylhexyl salicylate 5 5

Ethylhexyl triazone 3.5 3.5

Octocrylene 6 6

Drometrizole trisiloxane 0.25 0.25

Bis(ethylhexyloxyphenol)methoxyphenyltriazine 0.5 0.5

Table 2

Examples 4 and 5 of alcohol-free antisun oil according to the invention are stable after storage for 2 months at various temperatures (4, 25 and 45°C). They also have the advantage of being vaporizable and cosmetically pleasant. They have an SPF of about 20. Examples 6 and 7:

Ingredients Ex. 6 Ex. 7

Plant oils 50 50

Isododecane 12.72 -

Undecane/tridecane mixture according to example - 12.2

1 or example 2 of document

WO 2008/155 059

C-12-C-1 5 alkyl benzoate 13 13

(Tegosoft TN from Evonik Goldschmidt)

Ethylenediamine/stearyl dimer dilinoleate copolymer 6 6

(Uniclear 100 VG - Arizona Chemical)

Butylmethoxydibenzoylmethane 3.5 3.5

Ethylhexyl salicylate 5 5

Ethylhexyl triazone 1 .3 1 .3

Octocrylene 5 5

Drometrizole trisiloxane 1 1

Diethylhexylbutamidotriazone 3 3 Table 2

Examples 6 and 7 of alcohol-free antisun oil according to the invention are stable after storage for 2 months at various temperatures (4, 25 and 45°C). They also have the advantage of being vaporizable and cosmetically pleasant. They have an SPF of about 30.

Claims

1. Anhydrous fluid composition free of C1 -C5 alkanol, comprising, in a cosmetically acceptable medium:

a) at least one lipophilic polyamide polycondensate, and

b) at least one linear or branched volatile alkane, and

c) at least one lipophilic organic UV-screening agent.

2. Composition according to Claim 1 , in which the lipophilic polyamide polycondensate(s) are chosen from the polymers of formula (A) below:

in which:

n is an integer ranging from 1 to 30;

R'₄ represents independently in each case: a hydrogen atom, an alkyl group comprising from 1 to 10 carbon atoms, or a direct bond to at least one group chosen from R'₃ and another R'₄ such that when the said group is another R'₄, the nitrogen atom to which are attached both R'₃ and R'₄ forms part of a heterocyclic structure defined by R'₄-N-R'₃, on condition that at least 50% of the R'₄ represent a hydrogen atom, and

3. Composition according to Claim 2, in which the lipophilic polyamide polycondensate(s) are chosen from the polymers of formula (A) in which the bonding group L represents an ester group

-C— O—

0 4. Composition according to Claim 3, in which the lipophilic polyamide polycondensate(s) are chosen from the polymers of formula (B) below:

in which:

- m denotes a whole number of amide units such that the number of ester groups represents from 10% to 50% of the total number of ester and amide groups;

- Ri is independently in each case an alkyl or alkenyl group containing at least 4 carbon atoms and especially from 4 to 24 carbon atoms;

5. Composition according to Claim 4, in which the polycondensate of formula (B) is a mixture of copolymers of a C36 diacid condensed onto ethylenediamine; the ester end groups result from the esterification of the remaining acid end groups with cetyl alcohol, stearyl alcohol or mixtures thereof (INCI name: Ethylenediamine/stearyl dimer dilinoleate copolymer).

6. Composition according to Claim 2, in which the polycondensate of formula (A) is a polycondensate comprising at least one terminal fatty chain bonded to the polymer backbone via at least one tertiary amide bonding group (APTA).

7. Composition according to Claim 6, in which the polycondensate is a copolymer of hydrogenated dilinoleic diacid, of ethylenediamine and of di(Cu- C-i 8)alkylamine(s) (INCI name: Ethylenediamide/hydrogenated dimer dilinoleate copolymer bis-di-Cu-Ci 8 alkyl amide).

8. Composition according to Claim 2, in which the polycondensate of formula (A) is an ester-terminated poly(ester-amide) (ETPEA).

9. Composition according to Claim 8, in which the polycondensate of formula (A) is a copolymer of hydrogenated linoleic diacid, of ethylenediamine, of neopentyl glycol and of stearyl alcohol (INCI name: Bis-stearyl ethylenediamine/neopentyl glycol/stearyl hydrogenated dimer dilinoleate copolymer).

10. Composition according to any one of claims 1 to 9, in which the branched volatile alkane(s) are chosen from C8-C16 isoalkanes of petroleum origin.

11. Composition according to any one of Claims 1 to 10, in which the branched volatile alkane(s) are chosen from volatile linear alkanes.

12. Composition according to any one of Claims 1 to 1 1 , in which the volatile linear alkane(s) comprise from 7 to 14 carbon atoms, preferably from 8 to 14 carbon atoms and more preferentially from 1 1 to 14 carbon atoms.

13. Composition according to any one of Claims 1 to 12, in which the volatile linear alkane(s) are of plant origin.

14. Composition according to any one of Claims 1 to 13, in which the volatile linear alkane(s) are chosen from n-heptane (C₇), n-octane (Cs), n-nonane (Cg), n- decane (C-io), n-undecane (Cn ), n-dodecane (C12), n-tridecane (C13) and n- tetradecane (Cu), and mixtures thereof.

15. Composition according to Claim 14, in which the volatile linear alkanes are chosen from a mixture of n-undecane (Cu ) and of n-tridecane (C13).

16. Composition according to Claim 15, comprising an n-undecane/n-tridecane (C11/C13) mixture comprising

a) from 55% to 80% by weight and preferably from 60% to 75% by weight of Cu volatile liquid linear alkane (n-undecane), and

b) from 20% to 45% by weight and preferably from 24% to 40% by weight of C13 volatile liquid linear alkane (n-tridecane) relative to the total weight of alkanes in the said mixture.

17. Composition according to any one of Claims 1 to 16, in which the lipophilic screening agent(s) are chosen from para-aminobenzoic acid derivatives, salicylic derivatives, cinnamic derivatives, benzophenones and aminobenzophenones, anthranilic derivatives, dibenzoylmethane derivatives, β,β-diphenylacrylate derivatives, benzylidenecamphor derivatives, phenylbenzimidazole derivatives, benzotriazole derivatives, triazine derivatives, bis-resorcinyl triazines, imidazoline derivatives, benzalmalonate derivatives, 4,4-diarylbutadiene derivatives, benzoxazole derivatives and merocyanins, and mixtures thereof.