FR2732905A1 - Use of per:fluoroalkyl-ethyl alkanoate ester(s) - Google Patents

Abstract

Use of perfluoroalkylethyl alkanoate esters of formula RfC2H4OCORh (I), (where Rf = 4-20C perfluoroalkyl and Rh = 1-29C alkyl) to prepare stable emulsions comprising at least one oil phase and an aq. phase is new. Also claimed are emulsions comprising an oil phase and an aq. phase, where the oil phase consists essentially (see below) of one or more cpds. (I). Also claimed are cosmetic, sanitary, pharmaceutical or food compsns. contg. an emulsion as above. (I) is 2-perfluorooctylethyl hexanoate, 2-decyltetradecanoate, octanoate, octadecanoate, docosanoate or decanoate, or 2-perfluorohexylethyl 2-butyloctanoate, 2-ethylhexanoate or octanoate. (I) are used to prepare emulsions which: contain 0.1-30 (esp. 0.5-20) wt.% (I); may also contain opt. fluorinated hydrocarbon oils, silicone oils and/or perfluorinated oils; are o/w, w/o or multiple emulsions; and/or have an aq./oil phase ratio of 0.1-9, esp. 1.5-5. (I) make up \- 50 (esp. \- 75) wt.% of the oil phase, which may also contain oil-soluble additives, esp. vitamins, perfumes, fatty acids, lipids and ceramides.

Description

The present invention relates to the use of at least one hydrofluorocarbon compound as a stabilizing agent of an emulsion.

 It is known to use perfluoropolyethers, especially in the field of cleaning, protection and make-up of the skin or hair. These compounds are known for their low surface tension and their ease of spreading, but have a very low solubility in most fluids, except in fluorinated fluids, which makes their formulation in cosmetics very difficult. Some of its compounds, perfluoromethylisopropyl ethers, are known as Fomblin HC, and are marketed by MONTEFLUO.

 FR 2 684 668 discloses hydrofluorocarbon compounds having a good solubility, especially in conventional solvents. They make it possible to obtain stable and homogeneous emulsions.

The Applicant has raised the problem of further improving the quality and stability of the emulsions, whatever the nature of the oils used.

The present invention therefore aims to propose new hydrofluorocarbon compounds as an emulsion stabilizer.

The invention therefore relates to the use as stabilizing agent in an emulsion of at least one hydrofluorocarbon compound of formula (I) RF - C2H4-O-CO-RH in which: RF represents a linear alkyl group or branched, perfluorinated having from 4 to 20 carbon atoms, and
RH represents a linear or branched alkyl group having from 1 to 29 carbon atoms.

It has indeed been found that the presence of at least one compound of formula (I), or a mixture of these compounds, in an emulsion, and in particular in the fatty phase of the emulsion, could make it possible to improve the stability of said emulsion, whatever the chemical nature of the fatty phase used.

In addition, the emulsions comprising said stabilizing agent are directly formable, that is to say that they can be directly used, in particular in the context of an application in cosmetics, hygiene or pharmacy.

The radical RF may preferably represent a perfluorinated alkyl group having 4 to 10 carbon atoms and the radical RH a linear or branched alkyl group having 1 to 15 carbon atoms.

Among the compounds of formula (I) that may be used in the context of the invention, mention may be made of 2-F-octyl ethyl hexanoate, 2'-F-hexyl ethyl 2-butyl-octanoate and 2-ethyl 2'-F-hexylethyl hexanoate, 2'-F-octyl ethyl 2-decyl-tetradecanoate, 2-F-hexyl ethyl octanoate, 2-F-octyl ethyl octanoate, I ' 2-F-octyl ethyl octadecanoate, 2-F-octyl ethyl docosanoate and 2-F-octyl ethyl decanoate.

The stabilizing agent may be present in the emulsion, preferably in the fatty phase, in a proportion of 0.1 to 30% by weight, preferably 0.5 to 20% by weight.

The fatty phase of the emulsion further comprises at least one oil, which may be chosen in particular from hydrocarbon oils, optionally fluorinated, silicone oils and perfluorinated oils, alone or as a mixture.

The fatty phase may further comprise liposoluble additives conventionally used in the field of application, such as vitamins, perfumes, fatty acids, lipids, especially ceramides.

The aqueous phase of the emulsion according to the invention may also comprise hydrophilic additives conventionally used, such as glycerol and urea.

The ratio aqueous phase / oily phase in the emulsion may be between 9 and 0.1, preferably 5-1.5. The emulsion according to the invention may therefore be an oil-in-water or water-in-oil emulsion, or even a multiple emulsion.

The emulsion comprising the stabilizing agent may be used as a composition, or in a composition, in particular in the cosmetics, hygiene, pharmaceutical and even food industries.

Such a composition comprising the stabilized emulsion according to the invention may furthermore comprise any additive usually used in the field under consideration, such as surfactants, moisturizing agents, thickeners, softeners, sunscreens, treatment agents, anti-foam agents, perfumes, preservatives, antioxidants, sequestering agents, flavoring agents, basifying or acidifying agents, fillers and pigments, emulsifiers, co-emulsifiers.

Said composition may be in particular in the form of a gel, a milk or a cream. In particular, it may be in the form of a product intended for makeup and / or care of the skin or of keratin materials, or in the form of a product for coloring the hair or a protective product solar skin and / or keratin materials.

The compound of formula (I) may be prepared according to a conventional esterification process which consists of mixing, in an acidic medium, preferably in the presence of a solvent, an acid of formula RH-COOH with an alcohol of formula
RF - C2H4 - OH, in which the radicals RH and RF have the same meanings as before.

Another esterification process for preparing the compound of formula (I) comprises reacting an alcohol of formula RF - C2H4 - OH with an activated derivative of the alcohol of formula RH - CO - Y in which RH has the same meaning. than previously, and Y represents an activating group, in particular of the halogen type, mixed or symmetrical anhydride residue, or imidazole.

The following examples illustrate the invention. Examples 1 to 7 describe a process for the preparation of compounds used in the context of the present invention.

EXAMPLE 1 Preparation of 2-ethyl hexanoate of 2-F-hexyl ethyl
In a 1-liter reactor, 114.66 g of 2-F-hexyl ethanol and 43.2 g of 2-ethylhexanoic acid are introduced into 850 ml of toluene in the presence of 9 g of para-toluenesulphonic acid monohydrate.

The reaction mixture is refluxed with the solvent for 16 hours. The solution is concentrated to give an oil which is distilled to obtain 113 g of compound (77% yield).

The chemical analysis of the obtained product gives: - Boiling temperature: 115 "C at 0.3 mbar - 13C NMR spectrum: in accordance with the expected structure - Mass spectrum: in accordance with the expected structure - Elemental analysis:

<tb><SEP>% C <SEP>% H <SE>% F
<tb> Theoretical <SEP> 39.20 <SEP> 3.91 <SEP> 50.37
<tb><SEP> Calculated <SEP> 39.23 <SEP> 3.81 <SEP> 50.42
<Tb>
EXAMPLE 2 Preparation of 2-F-hexylethyl octanoate
In a 2 liter reactor, 43.2 g of octanoic acid and 114.7 g of 2-F-hexylethanol are dissolved in 850 ml of toluene in the presence of 9 g of para-toluenesulphonic acid. The mixture is heated at reflux for 16 hours, then the solvent is evaporated to obtain an oil which is taken up in 800 ml of ethanol.

This solution is stirred for 15 minutes in the presence of 150 g of resin previously washed with water, a 50/50 ethanol / water mixture, then ethanol alone.

The resin is sintered glass and the solvent is evaporated to give an oil which is distilled under vacuum to provide 110 g of product (75% yield).

The chemical analysis of the obtained product gives: - Boiling temperature: 105 "C at 0.4 mbar - Mass spectrum: according to the expected structure - Elemental analysis:

<tb><SEP>% C <SEP>% H <SE>% F
<tb> Theoretical <SEP> 39.20 <SEP> I1 <SEP> 3.91 <SEP> 50.37
<tb><SEP> Calculated <SEP> 39.31 <SEP> 3.97 <SEP> 50.67
<Tb>
EXAMPLE 3 Preparation of 2-F-hexylethyl 2-butyloctanoate
In a reactor of 1.5 liters, 76.44 g of 2-F-hexyl ethanol and 40 g of 2-butyloctanoic acid are introduced into 850 ml of toluene in the presence of 6 g of para-toluenesulphonic acid monohydrate.

The reaction mixture is refluxed for 16 hours. The solution is concentrated to give an oil which is distilled to give the expected compound (73% yield).

The chemical analysis of the product obtained gives: - Boiling temperature 136 - 140 ° C at 0.6 mbar - Mass spectrum: in accordance with the expected structure - 13 C NMR spectrum: in accordance with the expected structure - Elemental analysis:

<tb><SEP>% C <SEP>% H <SEP>
<tb> Theoretical <SEP> 43.96 <SEP> 4.98 <SEP> i <SEP> 45.20
<tb><SEP> Calculated <SEP> 43.84 <SEP> 4.91 <SEP> 45.49
<Tb>
EXAMPLE 4 Preparation of 2-F-octyl ethyl 2-decyl tetradecanoate
In a 1-liter reactor, 69.6 g of 2-F-octyl ethanol and 46.8 g of 2-decyltetradecanoic acid are introduced into 640 ml of toluene in the presence of 4.49 g of para-toluenesulphonic acid. monohydrate.

The reaction mixture is refluxed with the solvent for 16 hours. The solvent is evaporated to give an oil which precipitates by adding 500 ml of ethanol. The solid obtained is filtered and washed twice with ethanol. After drying under reduced pressure, 78 g of a white solid are obtained (yield 76%).

The chemical analysis of the product obtained gives: - Melting temperature: 43 ° C - Mass spectrum: according to the expected structure - 13C NMR spectrum: in accordance with the expected structure - Elemental analysis:

<tb><SEP>% C <SEP>% H
<tb> Theoretical <SEP> 50.12 <SEP> 6.31 <SEP> 39.64
<tb><SEP> Calculated <SEP> 50.06 <SEP> 6.26 <SEP> 39.64
<Tb>
EXAMPLE 5 Preparation of 2-F-octyl ethyl octadecanoate
In a 1-liter flask, 69.6 g of 2-F-octyl ethanol are dissolved in 200 ml of tetrahydrofuran, and 12.64 g of pyridine is then added. The solution is cooled to 5 ° C. and 45.38 g of stearyl chloride are poured into the mixture in 100 ml of tetrahydrofuran in the course of 30 minutes, then the mixture is allowed to return to ambient temperature and the mixture is stirred for 1 hour.

The mixture is concentrated and the expected product is precipitated by addition of 500 ml of ethanol. The solid obtained is filtered and washed and recrystallized from ethanol.

After drying under reduced pressure, 58 g of a white solid are obtained (yield 53%).

Analysis of the product obtained gives: Fusion temperature: 40 ° C. Mass spectrum: according to the expected structure. Elemental analysis:

<tb><SEP>% C <SEP>% H <SEP> T <SEP><SEP>% F
<tb> Theoretical <SEP> 46.03 <SEP> 5.38 <SEP> 44.21
<tb><SEP> Calculated <SEP> 46.44 <SEP> 5.42 <SEP> 43.53
<Tb>
EXAMPLE 6 Preparation of 2-F-octyl ethyl hexanoate
In a 2 liter reactor, 34.8 g of hexanoic acid and 146.16 g of 2-F-octyl ethanol are dissolved in 850 ml of toluene in the presence of 9 g of para-toluenesulphonic acid. The mixture is heated at reflux for 36 hours, then the solvent is evaporated to obtain an oil which is taken up in 600 ml of ethanol.This solution is stirred for 15 minutes in the presence of 150 g of resin previously washed with water , a 50/50 mixture ethanoil water, then ethanol alone.

The resin was sintered glass and the solvent was evaporated to give an oil which was distilled under reduced pressure to provide 143 g (0.254 mole) of the expected ester (85% yield).

The chemical analysis of the product obtained gives - Boiling temperature 107 - 20C at 0.4 mbar - Mass spectrum: in accordance with the expected structure - NMR spectrum 1H and 13C: in accordance with the expected structure - Elemental analysis

<tb><SEP>% C <SEP>% H
<tb> Theoretical <SEP> 34.18 <SEP> 2.69 <SE> 57.44
<tb><SEP> Calculated <SEP> 34.12 <SEP> 2.73 <SEP> 57.59
<Tb>
EXAMPLE 7 Preparation of 2-F-octyl ethyl docosanoate
97.44 g of 2-F-octyl ethanol and 68 g of docosanoic acid are introduced into a 1-liter reactor in 800 ml of toluene in the presence of 6 g of para-toluenesulphonic acid monohydrate.

The reaction mixture is refluxed with the solvent for 24 hours. The solvent is evaporated to obtain a wax which is recrystallized from absolute ethanol. 132.2 g of a white solid are finally obtained (yield 84%).

The chemical analysis of the product obtained gives - Melting temperature: 70.6 ° C - Mass spectrum: in accordance with the expected structure - NMR'3C spectrum: in accordance with the expected structure - Elemental analysis:

<tb><SEP> | <SEP>% C <SEP><SEP>% H <SEP>
<tb> Theoretical <SEP> 48.86 <SEP> 6.02 <SEP> 41.05
<tb><SEP> Calculated <SEP> 49.02 <SEP> 6.01 <SEP> 40.81
<Tb>
EXAMPLE 8
This example consists in comparing the stability of a stabilized emulsion according to the invention with a stabilized emulsion according to the prior art (FR 2,684,668).

Prior art (% by weight).

. 1- (2'-F-hexylethylthio) 3- (2-ethylhexyloxy) -2-propanol 4.5%
. silicone oil (cyclopentadimethylsiloxane) 45.5%
. emulsifier (polymer consisting of 80% methacrylic acid and 20% lauryl methacrylate, 80% neutralized) 1%
water qs 100%
Invention (% by weight).

in example 1 4.5%
silicone oil (cyclopentadimethylsiloxane) 45.5%
. emulsifier (80% methacrylic acid / 20% lauryl methacrylate polymer, 80% neutralized) 1%
water qs 100%
The stability of the emulsion according to the invention is clearly superior compared with that of the emulsion of the state of the art.

Indeed, the emulsion according to the invention remains stable for more than 100 days, during storage at 20 ° C., whereas the emulsion according to the state of the art only remains stable for about 35 days; then observe a demixing of the emulsion.

EXAMPLE 9
The stability of emulsions comprising the stabilizing agent according to the invention is compared with the same emulsions without stabilizer.

We obtain the following results 1st comparison
Invention (% by weight)
example of example 1 10%
. triglycerides of caprylic and capric acids 40%
. emulsifier (80% methacrylic acid / 20% lauryl methacrylate polymer, 80% neutralized) 1%
water qs 100%
Prior art
caprylic and capric acid triglycerides 50%
. emulsifier (80% methacrylic acid / 20% lauryl methacrylate polymer, 80% neutralized) 1%
. water qs 100%
The stability of the emulsion according to the invention is clearly superior compared with that of the emulsion of the state of the art. The emulsion according to the invention remains stable for more than 80 days, during storage at 20 ° C., whereas the emulsion according to the state of the art remains stable only about 9 days under the same conditions.

2nd comparison
Invention (% by weight)
composed of example 2 10%
. palmitic ester of ethyl-2-hexyl glyceryl ether 40%
. emulsifier (80% methacrylic acid / 20% lauryl methacrylate polymer, 80% neutralized) 1%
. water qs 100%
Prior art
palmitic ester of ethyl-2-hexyl glyceryl ether 50%
. emulsifier (80% methacrylic acid / 20% lauryl methacrylate polymer, 80% neutralized) 1%
water qs 100%
The stability of the emulsion according to the invention is clearly superior compared with that of the emulsion of the state of the art. The emulsion according to the invention remains stable for more than 80 days, during storage at 20 ° C. C, whereas the emulsion according to the state of the art remains stable only about 45 days under the same conditions.

3rd comparison
Invention (% by weight)
. compound of example 1 10%
. cyclopentadimethylsiloxane 40%
. emulsifier (polymer 80% methacrylic acid 120% lauryl methacrylate, 80% neutralized) 1%
water qs 100%
Prior art
. cyclopentadimethylsiloxane 50%
. emulsifier (80% methacrylic acid / 20% lauryl methacrylate polymer, 80% neutralized) 1%
. water qs 100%
The stability of the emulsion according to the invention is clearly superior compared with that of the emulsion of the state of the art. The emulsion according to the invention remains stable for more than 15 days, during storage at 20 ° C., whereas the emulsion according to the state of the art remains stable only about 7 days under the same conditions.

Claims (11)

1. Use of at least one hydrofluorocarbon compound of formula (I)  RF - C2H4 - O - CO - RH wherein: RF represents a linear or branched, perfluorinated alkyl group having from 4 to 20 carbon atoms, and  RH represents a linear or branched alkyl group having from 1 to 29 carbon atoms as a stabilizing agent in an emulsion. 2. Use according to claim 1, wherein RF represents a perfluorinated alkyl group having 4 to 10 carbon atoms. 3. Use according to one of the preceding claims, wherein RH represents a linear or branched alkyl group having 1 to 15 carbon atoms. 4. Use according to one of the preceding claims, wherein the stabilizing agent is selected from 2-F-octyl ethyl hexanoate, 2'-F-hexyl ethyl 2-butyl-octanoate, 2-ethyl 2'-F-hexylethyl hexanoate, 2'-F-octyl ethyl 2-decyl-tetradecanoate, 2-F-hexyl ethyl octanoate, 2-Foctyl ethyl octanoate, octadecanoate, 2-F-octyl ethyl, 2-F-octyl ethyl docosanoate and 2-F-octyl ethyl decanoate. 5. Use according to one of the preceding claims, wherein the stabilizing agent is present in the fatty phase of the emulsion. 6. Use according to one of the preceding claims, wherein the stabilizing agent is present in the emulsion in an amount of 0.1 to 30% by weight. 7. Use according to claim 6, wherein the stabilizing agent is present in the emulsion in an amount of 0.5-20% by weight. 8. Use according to one of the preceding claims, wherein the fatty phase of the emulsion comprises at least one oil, which may be selected from hydrocarbon oils, optionally fluorinated, silicone oils, perfluorinated oils, alone or in admixture. . 9. Use according to one of the preceding claims, wherein the emulsion is an oil-in-water or water-in-oil emulsion or a multiple emulsion. 10. Use according to one of the preceding claims, in an emulsion used in the cosmetic, hygienic, pharmaceutical or food. 11. Use according to one of the preceding claims, in an emulsion usable in or as a product for makeup and / or care of the skin or keratin materials, or a hair coloring product or a sunscreen product. skin and / or keratin materials.