The present invention relates to a volatile oily composition comprising, and preferably consisting of, a mixture of paraffins and optionally at least one non-volatile oil. It also relates to the cosmetic composition containing the abovementioned oily composition, and the cosmetic uses of said cosmetic composition, particularly for makeup and/or care for skin, lips, eyelashes and/or nails.

Although volatile silicones such as cyclomethicone have been considered for a long time to be harmless emollients and solvents for skin (see in particular International Journal of Toxicology, Vol. 10, No. 1, pp. 9-19, 1991), concerns have been raised in recent years in relation to the potential harmful effects thereof on the environment, or on human health (particularly in relation to octamethylcyclotetrasiloxane).

Research was thus undertaken to identify compounds suitable for offering a satisfactory alternative to volatile silicones, i.e. with similar volatility characteristics and similar behaviour in the formulation of cosmetic products, particularly in terms of the viscosity thereof, and having equivalent sensorial properties to those provided by volatile silicones, particularly in terms of applicability on the skin and the soft, â€œdryâ€ and non-greasy texture of the film obtained.

In this way, the application US 2005/0079986 proposes an oily composition containing a mixture of a linear or branched dialkyl carbonate with an alkane, preferably branched and saturated, containing 8 to 40 carbon atoms. Similarly, the application US 2004/0241200 suggests the use of an association of isoparaffin (such as isododecane) with a neopentyl glycol polyester (such as neopentyl glycol diheptanoate) as a substitute for pentameric (D5) and tetrameric (D4) cyclomethicones. This mixture is particularly marketed by INOLEX under the brand name LexfeelÂ® D4 and D5. PRESPERSE LLC also offers, under the brand name SiCloneÂ® SR-5, a mixture of C₁₃-C₁₆and C₁₂-C₁₄isoparaffins with C₁₃-C₁₅alkanes, as a cyclomethicone substitute. Finally, other attempts consisted of offering raw materials from renewable sources. This is the case of caprylyl isostearate which is the result of the esterification of 2-octanol by a mixture C₁₈fatty acid isomers (U.S. Pat. No. 6,126,951), but also of the mixture of linear paraffins disclosed in WO 2008/155059. This mixture comprises at least two hydrocarbons which differ from at least two carbon atoms. These hydrocarbons are preferably chosen from those having an odd number of carbon atoms from C₁₁to C₂₁, most preferably a mixture of C₁₁and C₁₃hydrocarbons. Other linear paraffins are those marketed by SASOL under the trade name LinparÂ® 10-13, which comprise a mixture of linear hydrocarbons from C₉to C₁₄and more, and by SONNEBORN under the trade name LilacÂ®, which comprise a mixture of alkanes from C₁₄to C₂₂.

However, there is still a need for an oily composition having very similar physicochemical and sensorial characteristics to those of cyclomethicones and consequently capable of being substituted for same in the formulation, in particular, of cosmetic products.

Very unexpectedly, the Applicant discovered that this need was met by an oily composition based on paraffins which, unlike the substitutes of the prior art, such as isoparaffins and fatty acid esters, have a linear and non-branched structure.

The present invention thus relates to a volatile oily composition comprising and preferably consisting of:

(a) from 50 to 100% by weight of a mixture of linear paraffins consisting of:

(i) 70 to 99% by weight of at least one linear paraffin selected from C₈, C₁₀, C₁₂paraffins and mixtures thereof,

(ii) 1 to 30% by weight of at least one C₁₄to C₂₄linear paraffin, and

(b) from 0 to 50% by weight of at least one non-volatile oil.

Firstly, it should be noted that, in the description and the following claims, the expression â€œbetweenâ€ should be understood as including the cited limits.

Indeed, the Applicant demonstrated that the abovementioned association of raw materials had a volatility within the same range as cyclomethicones, i.e. a vapour pressure in the region of 0.001 to 300 mm Hg and preferably from 0.01 to 10 mm Hg at ambient temperature (20Â° C.) and atmospheric pressure, and an emollient nature and easy application on the skin, such that compositions containing this association leave, on the skin, after penetration in the outer layers thereof, a film having a soft, non-greasy touch and a reduced gloss similar to those of cyclomethicones. This oily composition further advantageously has a flash point (measured as per the ASTM D93 standard) below 100Â° C., preferably between 50 and 95Â° C., for example between 70 and 90Â° C., more preferably between 75 and 85Â° C. and, even better, between 75 and 80Â° C., and/or a kinematic viscosity below 5 cSt, or between 1 and 3 cSt, at 40Â° C.

This association of raw materials may thus partly or completely substitute the volatile silicones conventionally used in cosmetic compositions and more particularly cyclopentasiloxane and mixtures containing same (such as DC345Â® sold by DOW CORNING).

The paraffins (or fatty alkanes) contained in the oily composition according to the invention may be advantageously obtained according to a method comprising the following successive steps:

1â€”dehydration of at least one C₈-C₂₄fatty alcohol to obtain an alkene, and

2â€”hydrogenation of said alkene to an alkane.

The first step of this method may particularly be implemented as described in the document US 2008/0287722, i.e. at a temperature of 190 to 260Â° C., preferably of 220 to 250Â° C., in the presence of a dehydration catalyst consisting of trifluoromethane sulphonic acid, which may represent 0.5 to 3% of the weight of the alcohol, for example. The alcohol dehydrated in this step may be obtained from plant sources and particularly be obtained by saponification of natural oils or fats. However, it is preferable for it to be obtained according to a method comprising a transesterification step of fatty acid triglycerides, preferably of plant origin, followed by a hydrogenation step of the fatty acid esters (for example methyl esters) obtained. The use of fatty alcohols of plant origin leads to alkenes containing an even number of carbon atoms, generally in mixture form. This mixture may also comprise a minor amount of branched alkenes.

The second step of this method may be implemented in a conventional manner for those skilled in the art, according to techniques used in the food processing industry for hydrogenating oils, and particularly placing the alkene(s) in contact with a catalyst comprising a transition metal. The alkanes obtained preferably contain, as above, an even number of carbon atoms. They are linear, although they may also include a minor amount of branched alkanes.

Obviously, this method may further comprise other steps (preliminary, intermediate and/or subsequent steps) than those mentioned above.

Alternatively, commercially available paraffins, such as those available from SASOL under the brand name ParafolÂ® (particularly ParafolÂ® 14-97 for tetradecane) may be used in the oily composition according to the invention.

The oily composition according to the invention comprises 70 to 99% by weight, for example 70 to 90% or 90 to 99% by weight, C₈, C₁₀and/or C₁₂paraffin(s) and 1 to 30% by weight, for example 10 to 30% or 1 to 10% by weight, C₁₄to C₂₄paraffin(s). These two types of paraffins may be obtained separately and mixed, or obtained jointly from a mixture of fatty alcohols, particularly of plant origin, according to the method described above. Among the C₈, C₁₀and/or C₁₂paraffin(s), the C₁₂paraffin is preferred. Moreover, as explained above, the C₁₄to C₂₄paraffin(s) are preferably chosen among those having an even number of carbon atoms, still preferably the C₁₄paraffin.

Furthermore, preferably, the oily composition according to the invention comprises, or consists only of, dodecane and tetradecane.

In addition to the abovementioned paraffins, and according to the desired volatility, the oily composition according to the invention may contain at least one non-volatile oil. According to the present invention, the term â€œoilâ€ refers to a liquid compound at ambient temperature (25Â° C.), which, when introduced at a rate of at least 1% by weight in water at 25Â° C., is not at all soluble in water, or soluble at a rate of less than 10% by weight, with reference to the weight of oil introduced into the water. In this description, the term â€œnon-volatile oilâ€ refers to an oil remaining on the skin at ambient temperature and atmospheric pressure for a plurality of hours, in the absence of friction, and/or having a vapour pressure less than 0.001 mm Hg under these conditions.

Examples of non-volatile oils include: mineral or synthetic branched hydrocarbons, synthetic (poly)esters and (poly)ethers and particularly (poly)esters of C₂-C₂₄(preferably C₆-C₂₀) acids and C₂-C₂₄(preferably C₆-C₂₀) alcohols or polyols, which are advantageously branched, C₆-C₂₀fatty acid triglycerides, vegetable oils, dialkyl carbonates such as dicaprylyl carbonate, branched and/or unsaturated fatty acids (such as linoleic and linolenic acids), branched and/or unsaturated fatty alcohols (such as octyldodecanol or hexyldecanol), silicone oils, fluorosilicone oils, fluorinated oils, and mixtures thereof.

The term â€œhydrocarbonâ€ refers to an oil containing only hydrogen and carbon atoms. Examples of non-volatile hydrocarbon oils are polybutene, hydrogenated polyisobutene, polydecene, hydrogenated polydecene, squalane, non-volatile paraffin oils and mixtures thereof.

The (poly)esters of C₂-C₂₄acids and C₆-C₂₀alcohols and polyols, which represent the preferred category of non-volatile oils according to the invention, particularly include mono- and diesters such as ethyl acetate, isopropyl acetate, oleyl acetate, isononyl isononanoate, ethylhexyl isononanoate, hexyl neopentanoate, ethylhexyl neopentanoate, isodecyl neopentanoate, isostearyl neopentanoate, heptyl undecylenate, neopentylglycol diheptanoate, neopentylglycol diethylhexanoate, pentaerythrityl tetraethylhexanoate, propanediol dicaprylate, neopentylglycol dicaprylate/dicaprate, isopropyl myristate, isopropyl palmitate, hexyl laurate, the mixture of coco caprate and caprylate, C₁₂to C₁₅alcohol benzoates, and mixtures thereof.

Examples of vegetable oils are in particular wheat germ, sunflower, grape seed, sesame, corn, apricot, castor, shea, avocado, olive, soya, sweet almond, palm, rapeseed, cotton, hazelnut, macadamia, jojoba, alfalfa, poppy seed, pumpkin seed, sesame, marrow, rapeseed, blackcurrant, evening primrose, millet, barley, quinoa, rye, safflower, candlenut, passiflora, musk rose or camellia oils.

The term â€œsilicone oilâ€ refers to an oil comprising at least one silicon atom, and particularly at least one Siâ€”O group. Non-volatile silicon oils particularly include polydimethylsiloxanes containing at least 8 silicon atoms, polyalkylmethylsiloxanes in which the alkyl chain contains 8 to 20 carbon atoms and oils identified using the INCI name phenyl trimethicone.

The oily composition according to the invention contains 50 to 100% by weight of paraffin mixture and 0 to 50% by weight of non-volatile oil(s), for example 70 to 95% by weight, preferably 85 to 95% by weight, of paraffin mixture and 5 to 30% by weight, preferably 5 to 15% by weight, of non-volatile oil(s).

Oily compositions according to this invention are also marketed by BIOSYNTHIS under the trade name VegelightÂ®.

The oily composition described above is advantageously intended for use in the formulation of a cosmetic composition, particularly suitable for making up and/or caring for and/or protecting skin, lips, eyelashes and/or nails.

Therefore, the present invention also relates to a cosmetic composition containing the oily composition described above, along with the uses thereof.

This cosmetic composition comprises a physiological acceptable and preferably cosmetically acceptable medium, i.e. which has no harmful side effects and particularly which does not cause unacceptable redness, inflammation, tautness or smarting for a user of cosmetic products.

This medium optionally comprises water and/or at least one oil, in addition to the abovementioned oily composition. The cosmetic composition according to the invention may thus be an anhydrous composition, an emulsion such as a water-in-oil (W/O) emulsion, an oil-in-water (O/W) emulsion or a multiple emulsion (particularly W/O/W or O/W/O), or a dispersion.

The oils particularly include those mentioned above as constituent (b) of the oily composition according to the invention, and volatile oils, which may particularly be selected from: branched hydrocarbons such as isododecane or isohexadecane, linear volatile silicone oils such as hexamethyldisiloxane or octamethyl trisiloxane, volatile fluorinated oils such as nonafluoromethoxybutane, and mixtures thereof.

The cosmetic composition according to the invention may further contain at least one of the following constituents: a fatty phase gelling or structuring agent, particularly a wax, a gum, an olefin copolymer or a silicone elastomer; a binder, particularly a fatty acid soap; an aqueous phase gelling or thickening agent, such as an acrylic or sulphonic homo- or copolymer (particularly based on AMPS); a film-forming agent, such as a PVP derivative, an acrylic latex or a silicone resin; a dispersant such as a fatty acid ester; an anionic, cationic or non-ionic surfactant and/or emulsifier, particularly a W/O, O/W or W/Si emulsifier; an active substance; an organic or inorganic photoprotective agent or UV filter; a filler; an optionally treated hydrophobic and/or lipophobic pigment; an organic or inorganic powder with a spherical and/or lamellar structure (such as silica, talc, mica, etc.); natural or synthetic fibres; a colorant; a complexing agent; a pH adjuster; a fragrance; a preservative; and mixtures thereof.

According to a preferred embodiment of the invention, one or a plurality of the above-mentioned constituents may be derived from renewable sources, i.e. obtained from raw materials of vegetable, bacterial or animal origin (preferably vegetable).

Furthermore, preferably, this composition is devoid of cyclic silicone (cyclomethicone), particularly cyclotetrasiloxane and cyclopentasiloxane derivatives.

This composition may take the form of a fluid, gel, cream, paste, foam, compressed or cast compact product or a solid product in stick form. It may consists of a facial or body care or hygiene product, particularly a moisturising, anti-age (anti-wrinkle and/or firming), depigmenting, pro-pigmenting or self-tanning, slimming, deodorant or antiperspirant product, or a UV protection product, a cleaner, makeup remover, massage oil or bath product. Alternatively, it may consist of a hair product, particularly a shampoo, conditioner or styling (particularly straightening) product or a hair colour product. Alternatively again, the cosmetic composition according to the invention may consist of a makeup product for the skin, mucosa and/or appendages, particularly a foundation, lipstick, lip gloss, blusher or eye shadow, mascara, eye liner or nail varnish.

The oily composition may particularly be used to improve the wear of mascara, lipstick or foundation and thus produce â€œtransfer-freeâ€ compositions. Alternatively, it may be used to improve the evaporation and/or application on the skin of antiperspirant or deodorant compositions, particularly roll-ons or in gel or stick form, particularly based on aluminium salts. Alternatively, it may be used to improve the spreading on skin of sunscreen compositions and/or the dispersion of pigments (especially inorganic nanopigments such as TiO₂and ZnO) within sunscreen compositions. Therefore, the invention also relates to these uses.

Furthermore, the Applicant found that this oily composition could be used as a vehicle for silicone polymers such as:

- silicone gums, particularly polydimethylsiloxanes hydroxylated at the terminal ends thereof, which are identified under the INCI name DIMETHICONOL,
- emulsifying or non-emulsifying silicone elastomers, which are crosslinked organopolysiloxanes, generally obtained by reacting, in the presence of a catalyst, an organosilicone such as an organohydrogenpolysiloxane with a polysiloxane containing at least one reagent group (hydrogen, allyl or vinyl, in particular) and comprising at least one alkyl (particularly method) or phenyl group and/or at least one polyoxyalkylene group, these groups being situated in a terminal and/or lateral position.

Examples of silicone elastomers are those identified by the INCI name DIMETHICONE/VINYL DIMETHICONE CROSSPOLYMER, particularly available commercially in oily gel form from GRANT INDUSTRIES under the brand GransilÂ®, from DOW CORNING under the brand name DC 9546Â® or from GENERAL ELECTRIC under the brand name SFE 839Â®, for example. Further examples include compounds having the INCI name LAURYL DIMETHICONE/VINYL DIMETHICONE CROSSPOLYMER marketed by SHIN-ETSU, particularly under the brand name KSG-31Â®. Other silicone elastomers are those having the INCI name DIMETHICONE CROSSPOLYMER, available for example from DOW CORNING under the brand name DC 9040Â®. Further examples include compounds having the INCI name POLYSILICONE-11, marketed particularly in oily mixture form by GRANT INDUSTRIES under the brand name GransilÂ® RPS, GransilÂ® GCM or GransilÂ® PC-12. A further example includes the compound having the INCI name CROSSLINKED STEARYL METHYL DIMETHYL SILOXANE COPOLYMER available from GRANT INDUSTRIES under the brand name GransilÂ® SR-CYC.

The oily mixture according to the invention may thus advantageously be used as a substitute for volatile silicone oils or isoparaffins contained in the abovementioned commercial mixtures.

Therefore, the present invention also relates to the use of the oily composition described above as a vehicle for silicone polymers such as elastomers or silicone gums.

The invention will be understood more clearly in the light of the following non-limitative examples, given merely for illustration purposes.

EXAMPLESExample 1FoundationW/O Emulsion

Using conventional methods for those skilled in the art, a composition containing the constituents identified in upper case letters in Table 1 below by the INCI name thereof (with reference to the CTFA Dictionary, 11^thEdition, 2006), in the percentages by weight specified opposite said constituents, was prepared.

TABLE 1PhaseConstituent%ACETYL PEG/PPG-10/1 DIMETHICONE2.80PHENYLTRIMETHICONE1.00POLYDECENE3.00CETEARYL ETHYLHEXANOATE2.00Mixture of C₁₂and C₁₄linear paraffins18.00BMICA0.50RED OXIDE & DIMETHICONE0.22YELLOW OXIDE & DIMETHICONE0.75BLACK IRON OXIDE & DIMETHICONE0.12TITANIUM DIOXIDE & DIMETHICONE8.50CSODIUM CHLORIDE1.25PHENOXYETHANOL0.50BUTYLENE GLYCOL5.00Waterq.s. 100.00Fragranceq.s.

Preparation:

The compounds of phase A were mixed for 10 minutes at 1000 rpm. After the constituents of phase B were mixed, they were added to phase A. The mixture of both phases was homogenised for 30 minutes at 2000 rpm. Phase C was prepared by dispersing the solid constituents thereof in water, and said phase was added to the emulsion previously obtained. The whole was homogenised for 15 minutes at 4500 rpm.

Evaluation:

The above composition (hereinafter, Composition 1A) was evaluated by a panel of 20 volunteers, compared to an identical formula (hereinafter, Composition 1B), but containing 18.00% by weight of cyclopentasiloxane (DOW CORNING DC 345Â®) instead of the mixture of C₁₂and C₁₄linear paraffins.

These compositions were considered to be identical in terms of the consistency, application homogeneity and covering and transfer-free (on blouse collars) effects thereof. The drying times and matting effect thereof were similar.

Therefore, no significant sensorial differences were perceived between these two formulas.

Example 2Dry Oil

Using conventional methods for those skilled in the art, a composition 2A containing the constituents identified in Table 2 below (where those in upper case letters are identified by the INCI name thereof), in the percentages by weight specified opposite said constituents, was prepared.

TABLE 2Constituent%CAPRYLIC/CAPRIC TRIGLYCERIDES10.00Jojoba oil5.00SQUALANE5.00OCTYLDODECANOL59.90GLYCINE SOYA & TOCOPHEROL0.10Mixture of C₁₂and C₁₄linear paraffins & HEXYL20.00LAURATEFragranceq.s.

This composition was evaluated by a panel of 30 volunteers, compared to the following compositions, in which the oily composition according to the invention was replaced by 20% by weight of the constituents specified below:

Composition 2B: dicaprylyl carbonate (COGNIS Cetiol CCÂ®)

Composition 2C: cyclopentasiloxane

Composition 2D: mixture of isododecane and neopentylglycol diheptanoate (INOLEX LexfeelÂ® D5)

It was observed that composition 2A according to the invention, like composition 2C, penetrated the skin rapidly, leaving a soft and non-greasy film thereon, whereas composition 2B penetrated more slowly and formed a residual film having a greasy texture. The volatile fraction of composition 2D evaporated rapidly to leave a film with a dry, but grating, unpleasant texture.

The superiority of the oily composition according to the invention was confirmed by substituting hexyl laurate with other esters, i.e.: ethylhexyl isononanoate (composition 2E), isostearyl neopentanoate (composition 2F) and propanediol dicaprylate (composition 2G). The features of all these compositions were equivalent, except that composition 2F gave the skin a more satiny effect.

A similar experiment was conducted in which two compositions 2H and 2Hâ€² according to this invention were compared. These were comprised of linear paraffins with 12 and 14 carbon atoms only, in different proportions. Composition 2H contained 30% of C₁₄paraffin while composition 2Hâ€² contained 10% of C₁₄paraffin. These were compared also with another composition 2Hâ€³ according to this invention, comprising 1% of C₁₄paraffin, 9% of an ester oil and 90% of C₁₂paraffin. Composition 2H provided a softer touch than composition 2Hâ€², which was very close to that provided by a standard composition based on CetiolÂ® CC. Composition 2Hâ€³ gave similar results to composition 2Hâ€² but a gloss somewhat higher which was not detrimental in this application.

Example 3Organic Anti-Age Cream

Using conventional methods for those skilled in the art, a composition containing the constituents identified in Table 3 below (where those in upper case letters are identified by the INCI name thereof), in the percentages by weight specified opposite said constituents, was prepared.

TABLE 3Constituent%CETEARYL ALCOHOL & CETEARYL GLUCOSIDE5.00Jojoba oil5.00Camellia oil5.00Shea butter5.00Beeswax2.00Waterq.s. 100.00Glycerine3.00Xanthan gum0.20Sodium hydroxide0.035Dehydroacetic acid0.80TOCOPHEROL & GLYCINE SOJA0.20Mixture of C₁₂and C₁₄linear paraffins & COCO1.00CAPRYLATE/CAPRATE

This composition was evaluated by a panel of 20 volunteers, compared to identical compositions containing greater quantities of oily composition according to the invention (2, 3 and 5% by weight, respectively).

It was observed that the oily composition according to the invention decreased the soap effect of this cosmetic composition, which had an increasingly soft velvety texture as the oily composition content increased. Besides, this composition provided for a slightly softer touch than DC345Â® and penetrated quickly into skin.

Example 4Anti-Perspirant

Using conventional methods for those skilled in the art, a composition containing the constituents identified in Table 4 below (where those in upper case letters are identified by the INCI name thereof), in the percentages by weight specified opposite said constituents, was prepared.

TABLE 4Constituent%CETYL PEG/PPG-10/1 DIMETHICONE2.00TRICLOSAN0.10DIMETHICONOL & VEGETABLE ALKANES (this invention)5.00ALUMINIUM SESQUICHLOROHYDRATE15.00ISODODECANE & DISTEARDIMONIUM HECTORITE &15.00PROPYLENE CARBONATEVEGETABLE ALKANES & COCO CAPRYLATE56.20(this invention)Butylene glycol and spirulina (Spiroxâ€‰Â®)0.03Fragrance6.67

Example 5Physical Properties

The oily mixture of this invention was compared with DC345Â® and two other paraffin mixtures, i.e. IsoparÂ® M which is a mixture of C_13-14isoparaffins and LinparÂ® 14-17 which is a mixture of C_14-17linear paraffins.

The results of this comparison are summarized in Table 5 below.

TABLE 5Vapour pressureComponentFlash point (Â° C.)*(mmHg)Cyclopentasiloxane and771cyclohexasiloxane (DC345â€‰Â®)C_13-C14isoparaffin (Isoparâ€‰Â® M)820.011C_14-17alkanes (Linparâ€‰Â® 14-17)118<0.01Mixture of C₁₂and C₁₄750.2alkanes (this invention)*according to ASTM D93

It follows from this Table that this invention provides a mixture of paraffins which has an evaporation profile closer to that of DC345Â®.

Example 6Sensorial Analysis

A comparison was made by volunteers between:

- composition 6A: an oily mixture according to this invention consisting of C₁₂and C₁₄paraffins and coco caprylate as an ester oil,
- composition 6B: DC345Â® and
- composition 6C: LilacÂ® (C_14-22alkanes).

The following parameters were assessed: smooth effect, quantity of residue, sticky effect, shiny effect, extension, fresh feel, greasy feel and wet effect. The three compositions tested compared similarly, except that composition 6A appeared much less shiny (grade about 5.5) than composition 6C (grade more than 7), with a gloss similar to that of composition 6B (grade about 6).

This example thus demonstrates the superiority of the oily mixture of this invention.