Composition in the form of an oil-in-water type nanoemulsion comprising at least one polyethoxylated nonionic surfactant, at least one liquid fatty substance and at least one silicone.

The present invention relates to a composition in the form of an oil-in-water type nanoemulsion comprising (i) at least one polyethoxylated nonionic surfactant, (ii) at least one fatty substance having a melting temperature less than 35 °C, chosen from vegetable oils, mineral oils and mixtures thereof, and (iii) at least one silicone.

The invention also relates to a preparation method for an oil- in-water type nanoemulsion comprising at least one polyethoxylated nonionic surfactant and at least one fatty substance having a melting temperature less than 35 °C, by a phase inversion process (PIT) .

Nanoemulsions, in particular the oil-in-water type (O/W), are well known in the cosmetics and dermatology domain, in particular for preparing cosmetic products such as lotions, creams, tonics, serums or eau de toilette to be applied to the skin and/or hair.

Nanoemulsions generally have a number-average oil drop (or oily globule) size less than 100 nanometers, said oil drops being stabilized by a layer of amphiphilic mo lecules that can optionally form a liquid crystal phase o f the lamellar type, located at the oil/aqueous phase interface. These nanoemulsions are transparent due to the small size o f the oily globules .

The term "amphiphilic mo lecule" means herein any mo lecule having a bipo lar structure, i. e. including at least one hydrophobic part and at least one hydrophilic part and having the property o f reducing the surface tension o f water (γ < 55mN/m) and o f reducing the interface tension between water and an oil phase. Amphiphilic mo lecules are for example surfactants, surface agents or emulsifiers .

Due to the small oil drop size, nanoemulsions offer a certain number of advantages from a cosmetic or dermatological point of view leading in particular to a homogeneous and effective deposit onto skin and/or hair while allowing satisfactory oil penetration and persistence.

Accordingly, nanoemulsions give improved cosmetic properties, particularly detangling, so ftness, feel, rinsability and conditioning effect for keratin substances such as hair, which are better than those obtained with classic emulsions and dispersions used in the cosmetic domain.

Furthermore, nanoemulsions o ffer the possibility o f delivering preparations with high oil content without having the drawback o f having an oily texture or giving keratin substances a greasy feel.

Besides, nanoemulsions currently marketed are generally obtained using a high pressure homogenization process (HPH) using equipment that has the drawback o f being extremely expensive in terms o f energy and maintenance.

In fact, the high pressure homogenization process requires specific and particularly heavy equipment to work under high pressures that can range from 12 x 10 ⁷ to 1 8 x 10 ⁷ Pa.

Consequently, such a process is not easy to use in industry.

Therefore there is a real need to manufacture compositions in the form o f oil-in-water type nanoemulsion that can lead to improved cosmetic properties while also being able to be prepared from a process using low energy and that can be easily industrialized.

The Applicant has discovered, in a surprising manner, that the combination (i) o f one or more specific polyethoxylated nonionic surfactants, (ii) o f one or more particular fatty substances and (iii) o f one or more silicones allows the obj ectives set out hereinbefore to be achieved.

Indeed, such a combination has the advantage of leading to the formation o f a combination in the form o f an oil-in-water type nanoemulsion from any type o f preparation process, and in particular from a process using low energy and that can be easily industrialized.

Specifically, such a combination allows the formation o f a composition in the form o f an oil-in-water type nanoemulsion from a phase inversion process (PIT), on conventional industrial equipment, particularly in double-j acketed tanks, which are significantly less expensive to use than a high pressure homogenization process, in particular in terms of purchase, energy and maintenance.

The polyethoxylated nonionic surfactants o f the fatty alcoho l ether type are in particular easy to use industrially, which makes them more manipulable during the preparation process o f the composition according to the invention.

In other words, the composition according to the invention can be obtained by any type o f process, and particularly by a phase inversion process (PIT) .

Moreover, the composition according to the invention has improved cosmetic properties compared with the classic compositions, in particular in terms of a smooth and homogeneous feel, so ftness, suppleness and detangling.

This results in that the composition in the form o f nanoemulsion according to the invention has both industrial and cosmetic interest because such a composition can be easily industrialized while having improved cosmetic properties .

The invention therefore in particular relates to a composition in the form of an oil-in-water type nanoemulsion comprising (i) one or more polyethoxylated nonionic surfactants of the fatty alcoho l ether type, (ii) one or more fatty substances having a melting temperature less than 35 °C, chosen from vegetable oils, mineral oils and/or mixtures thereof, and (iii) one or more silicones .

The composition according to the invention is preferably a cosmetic composition for treating keratin fibres, in particular human keratin fibres such as hair.

Due to the small oil drop size, the stability o f the composition is improved; a further observation is that the oil deposit on hair is more homogeneous and more persistent upon washing.

It has been observed that by using the composition according to the invention, it was possible to improve hair individualization, and their shine. The fibres are also smoother to the touch, so fter, more supple and detangle more easily. These properties are advantageously persistent upon washing.

In addition, the compositions according to the invention can influence hair volume, and reduce frizz.

Moreover, the tone of curly or wavy hair is also improved.

It is also possible to obtain long-lasting keratin fibre cleanliness, by using the compositions according to the invention, which will allow spacing hair washing and/or limiting it becoming greasy again between washings.

Finally, the compositions according to the invention give hair improved styling properties, in so far as the hair is more manageable.

The composition in the form o f a nanoemulsion also has the advantage o f having an average oil drop size by number that can advantageously be less than 200 nm, even better less than or equal to 100 nm.

Moreover, it is observed that the composition according to the invention is stable over time, in particular physically and chemically stable, i.e . it presents no changes in appearance (no decantation, remains in nanoemulsion form) .

Accordingly, the composition according to the invention has controlled particle size.

The composition according to the invention may be obtained by any type o f preparation process, for example a high pressure homogenization process, a phase inversion process (PIT) or a dilution process.

Given that the composition can be easily industrialized, it has the specific advantage o f being able to be obtained by a low cost process.

The present invention also relates to a preparation process for an oil-in-water type nanoemulsion comprising at least one fatty alcoho l ether-type polyethoxylated nonionic surfactant and at least one fatty substance having a melting temperature less than 35 ° C, by a phase inversion process (PIT) . The preparation process in particular presents the advantage o f being low energy and easily industrialized.

Specifically, the preparation process according to the invention is easier to implement industrially than a dilution method that involves a dropwise that can be slow.

The present invention also relates to a method for the cosmetic treatment of keratin fibres, in particular human keratin fibres such as hair, in which the composition according to the invention is applied to the said fibres .

Finally, the invention relates to the use of said composition for the cosmetic treatment of keratin fibres, particularly human keratin fibres such as hair.

In the same way, the composition according to the invention may also be used for treating skin.

Other subj ects, characteristics, aspects and advantages o f the invention will emerge even more clearly on reading the description and examples that follow.

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

Moreover, the expression " at least one" used in the present description is equivalent to the expression "one or more" .

As indicated hereinbefore, the composition in the form o f an oil-in-water type nanoemulsion contains (i) one or more fatty alcoho l ether type po lyethoxylated nonionic surfactants .

The nonionic surfactants used in the composition according to the invention have in their structure at least one hydrocarbon-based chain including at least 6 carbon atoms, in particular 8 to 30 carbon atoms.

Preferably, the nonionic surfactants are compounds having the fo llowing formula (I) :

R-(0-CH ₂ -CH ₂ ) _n -OH Formula (I) in which:

R represents a saturated or unsaturated, linear or branched hydrocarbon-based chain ranging from 8 to 30 carbon atoms, and

n represents an integer greater than 2, preferably greater than or equal to 4.

Preferably, R represents a saturated or unsaturated, linear or branched hydrocarbon-based chain, preferably linear, ranging from 10 to 20 carbon atoms, preferably ranging from 10 to 18.

Preferably, n is an integer less than or equal to 12.

More preferentially, n is an integer ranging from 2 to 12 and in particular from 4 to 12.

Advantageously, the nonionic surfactants have a melting temperature less than 35°C and preferentially a melting temperature less than or equal to 30°C, and even more preferentially a melting temperature less than or equal to 25°C, which makes them easier to manipulate during a preparation process, in particular a phase inversion process (PIT).

According to one embodiment, R represents a 1 i near unsaturated hydrocarbon-based chain having from 10 to 20 carbon atoms.

In accordance with this embodiment, the nonionic surfactant is preferably oleth-10.

According to another embodiment, R represents a linear saturated hydrocarbon-based chain having from 10 to 20 carbon atoms.

In accordance with this embodiment, the nonionic surfactant is preferably laureth-4.

The nonionic surfactants(s) may be present in the composition according to the invention in a content ranging from 1% to 20% by weight, in particular from 1.5% to 15% by weight, more preferably from 2% to 12% by weight relative to the total weight of the composition.

As indicated hereinbefore, the composition in the form of an oil-in-water type nanoemulsion contains (ii) one or more fatty substances having a melting point less than 35°C chosen from vegetable oils, mineral oils, or mixtures thereof.

According to the present application, the term "fatty substance" means an organic compound that is insoluble in water at room temperature (25°C) and at atmospheric pressure (1.013 x 10 ⁵ Pa), i.e. has a solubility of less than 5% by weight, and preferably less than 1% by weight, and even more preferably less than 0.1% by weight in water. They generally have in their structure a hydrocarbon-based chain including at least 6 carbon atoms.

In addition, the fatty substances are generally soluble in organic solvents under the same temperature and pressure conditions, for instance chloroform, dichloromethane, carbon tetrachloride, ethanol, benzene, toluene, tetrahydrofuran (THF), liquid petroleum jelly or decamethylcyclopentasiloxane.

The fatty substances according to the invention are not fatty acids.

Preferably, the fatty substances of the invention do not comprise any C2-C3 oxyalkylene units or any glycerol units.

Preferably, the fatty substances used in the composition have a melting point strictly less than 35°C, at ambient pressure (1.013 x 10 ⁵ Pa).

The fatty substances used in the composition according to the invention are preferentially liquid, i.e. having a melting point less than or equal to 25°C, at atmospheric pressure (1.013 x 10 ⁵ Pa).

Even more preferentially, the fatty substances are liquid at

28°C and at atmospheric pressure (760 mmHg or 1.013 x 10 ⁵ Pa).

Said liquid fatty substances are chosen from mineral oils and/or vegetable oils.

Among mineral oils, mention may in particular be made of liquid paraffin or liquid petroleum jelly.

Among vegetable oils, mention may in particular be made of h y d ro c a rb o n - b a s e d o i 1 s of vegetable origin, such as, for example, sweet almond oil. avocado oil. castor oil, coriander oil, olive oil, jojoba oil, sesame oil, groundnut oil, grape seed oil, rapeseed oil. coconut oil, hazelnut oil, shea butter, palm oil, apricot kernel oil, calophy!lum oil, rice bran oil, maize oil, wheat germ oil, soybean oil. sunflower oil, evening primrose oil, saffiower oil, passionflower oil, rye oil or triglycerides of caprylic capric acids, such as those sold by Stearineri.es Dubois or those sold under the names Migiyoi 810, 812 and 818 by Dynamit Nobel .

Preferably, the composit ion according to the invention comprises as fatty substance having a melting point less than 35°C, a mixture of at least one mineral oil a n d at least one vegetable oil.

The fatty substance(s) may be present in the composition according to the invention in an amount ranging from 0.1% to 50% by weight, preferentially from 0.5% to 40% by weight, more preferentially in a content from 1% to 30% by weight; even better from 2%> to 20%> by weight, or even from 3%> to 15 > by weight, relative to the total weight of the composition.

As indicated hereinbefore, the composition in the form of an oil-in-water type nanoemulsion according to the invention contains (iii) one or more silicones.

The silicones that can be used in the composition of the present invention may be volatile or non-volatile, cyclic, linear or branched silicones, modified or unmodified by organic substituents (called organomodified silicones), in particular amine substituents.

In the present description, the term "silicone", in accordance with what is generally accepted, means any organosilicon polymer or oligomer having linear or cyclic, branched or crosslinked structure, of variable molecular weight, that can be obtained by polymerization and/or polycondensation of suitably functionalized silanes, and consisting essentially of a repetition of main units in which the silicon atoms are linked together via oxygen atoms (siloxane bond -Si-O-Si-), optionally substituted hydrocarbon-based substituents being directly linked via a carbon atom to the said silicon atoms. The hydrocarbon- based substituents that are the most common are alkyl substituents, especially of Ci-Cio, and in particular methyl, fluoroalkyl substituents, the alkyl part of which is of Ci-Cio, and aryl substituents and in particular phenyl.

The silicones that can be used in accordance with the invention may be in the form of oils, waxes, resins or gums.

Preferably, the silicone is chosen from polydialkylsiloxanes, in particular polydimethylsiloxanes (PDMSs), and organomodified polysiloxanes including at least one functional group chosen from poly(oxyalkylene) groups, amino groups and alkoxy groups.

Organopolysiloxanes are defined in greater detail in Walter Noll's "Chemistry and Technology of Silicones" (1968), Academic Press. They may be volatile or non- volatile.

When they are volatile, the silicones are more particularly chosen from those having a boiling point of between 60°C and 260°C, and more particularly still from:

(i) cyclic polydialkylsiloxanes containing from 3 to 7 and preferably from 4 to 5 silicon atoms. These are, for example, octamethylcyclotetrasiloxane sold in particular under the name Volatile Silicone ^® 7207 by Union Carbide or Silbione ^® 70045 V2 by Rhodia, decamethylcyclopentasiloxane sold under the name Volatile Silicone ^® 7158 by Union Carbide, and Silbione ^® 70045 V5 by Rhodia, and mixtures thereof.

Mention may also be made of cyclocopolymers of the dimethylsiloxane/methylalkylsiloxane type, such as Volatile Silicone® FZ 3109 sold by the company Union Carbide, having formula:

D" - D' D" - D' ^■

CH CH,

I

with D" : ^— Si - O— with D' : - Si - O—

CH ₃ C ₈ H ₁₇

Mention may also be made of mixtures of cyclic polydialkylsiloxanes with organosilicon compounds, such as the mixture of octamethylcyclotetrasiloxane and tetra(trimethylsilyl)pentaerythritol (50/50) and the mixture of octamethylcyclotetrasiloxane and oxy- 1 , 1 '-bis(2,2,2 ',2' ,3,3 '- hexatrimethylsilyloxy)neopentane;

(ii) linear volatile polydialkylsiloxanes containing 2 to 9 silicon atoms and having a viscosity of less than or equal to 5 x 10 ^"6 m ² /s at 25°C. An example is decamethyltetrasiloxane sold in particular under the name SH 200 by the company Toray Silicone. Silicones belonging to this category are also described in the article published in Cosmetics and Toiletries, Vol. 91, Jan. 76, pp. 27-32, Todd &

Byers, Volatile Silicone Fluids for Cosmetics .

Use is preferably made of non-volatile polydialkylsiloxanes, polydialkylsiloxane gums and resins, polyorganosiloxanes modified with the organofunctional groups above, and mixtures thereof.

These silicones are more particularly chosen from polydialkylsiloxanes, among which mention may be made mainly of polydimethylsiloxanes bearing trimethylsilyl end groups. The viscosity of the silicones is measured at 25°C according to Standard

ASTM 445 Appendix C.

Among these polydialkylsiloxanes, mention may be made, in a nonlimiting manner, of the following commercial products:

- the Silbione® oils of the 47 and 70047 series or the Mirasil® oils sold by Rhodia, for instance the oil 70047 V 500000;

- the oils of the Mirasil® series sold by the company Rhodia;

- the oils of the 200 series from the company Dow Corning, such as DC200 with a viscosity of 60,000 mm ² /s;

- the Viscasil® oils from General Electric and certain oils of the SF series (SF 96, SF 18) from General Electric.

Mention may also be made of polydimethylsiloxanes having dimethylsilanol end groups known under the name dimethiconol (CTFA), such as the oils of the 48 series from the company Rhodia.

In this category of polydialkylsiloxanes, mention may also be made of the products sold under the names Abil Wax® 9800 and 9801 by the company Goldschmidt, which are poly(Ci-C2o)dialkylsiloxanes.

The silicone gums that can be used in accordance with the invention are in particular polydialkylsiloxanes and preferably polydimethylsiloxanes having high number-average mo lecular weights of between 200 ,000 and 1 ,000,000, used alone or as a mixture in a so lvent. This so lvent can be chosen from vo latile silicones, polydimethylsiloxane (PDMS) oils, polyphenylmethylsiloxane (PPMS) oils, isoparaffins, polyisobutylenes, methylene chloride, pentane, dodecane and tridecane, or mixtures thereof.

Products that may be used more particularly in accordance with the invention are mixtures such as :

the mixtures formed from a hydroxy-terminated polydimethylsiloxane or dimethicono l (CTFA), and from a cyclic polydimethylsiloxane, also known as cyclomethicone (CTFA), such as the product Q2 1401 sold by the company Dow Corning;

- mixtures of a polydimethylsiloxane gum and a cyclic silicone, such as the product SF 1214 Silicone Fluid from the company General Electric; this product is an SF 30 gum corresponding to a dimethicone, having a number-average mo lecular weight o f 500 000, dissolved in the oil SF 1202 Silicone Fluid corresponding to decamethy Icy clop entasiloxane;

- mixtures o f two PDMSs with different viscosities, and more particularly o f a PDMS gum and o f a PDMS oil, such as the product

SF 1236 from the company General Electric . The product SF 1236 is a mixture of a gum SE 30 defined above, with a viscosity of 20 m ² /s and of an oil SF 96 with a viscosity of 5 x 10 ⁶ m ² /s . This product preferably includes 15 % of gum SE 30 and 85 % of an oil SF 96.

The organopolysiloxane resins that may be used in accordance with the invention are crosslinked siloxane systems containing the fo llowing units :

R ₂ Si0 ₂ /2 , Rs SiO i/2 , RSi0 ₃ / ₂ and Si0 _4/2 ,

in which R represents an alkyl containing 1 to 16 carbon atoms. Among these products, the ones that are particularly preferred are those in which R denotes a C i -C ₄ lower alkyl group, more particularly methyl.

Mention may be made, among these resins, of the product sold as Dow Corning 593 or those so ld as Silicone Fluid S S 4230 and S S 4267 by General Electric, which are silicones having dimethyl/trimethylsiloxane structure.

Mention may also be made o f the resins o f the trimethylsiloxysilicate type, so ld in particular as X22-49 14, X21 -5034 and X21 -5037 by Shin-Etsu.

The organomodified silicones that may be used in accordance with the invention are silicones as defined previously and including in their structure one or more organofunctional groups attached via a hydrocarbon-based group .

Besides the silicones described above, the organomodified silicones may be polydiarylsiloxanes, in particular polydiphenylsiloxanes, and polyalkylarylsiloxanes functionalized by the organofunctional groups mentioned previously.

The polyalkylarylsiloxanes are particularly chosen from linear and/or branched polydimethyl/methylphenylsiloxanes and polydimethyl/diphenylsiloxanes with a viscosity ranging from l x l O ^"5 to 5 x l 0 ^"2 m ² /s at 25 °C .

Among these polyalkylarylsiloxanes, examples that may be mentioned include the products sold under the following names :

- the Silbione® oils of the 70 64 1 series from Rhodia;

- the oils o f the Rhodorsil® 70 633 and 763 series from Rhodia;

- the oil Dow Corning 556 Cosmetic Grade Fluid from Dow Corning;

- the silicones of the PK series from Bayer, such as the product

PK20;

- the silicones of the PN and PH series from Bayer, such as the products PN 1 000 and PH 1000;

- certain oils of the SF series from General Electric, such as SF 1023 , SF 1 154, SF 1250 and SF 1265.

Among the organomodified silicones, mention may be made o f polyorganosiloxanes including :

polyethyleneoxy and/or polypropyleneoxy groups optionally including C ₆ - C 24 alkyl groups, such as the products known as dimethicone copolyol sold by the company Dow Corning under the name DC 1248 or the oils Silwet® L 722, L 7500, L 77 and L 711 by the company Union Carbide, and the (Ci2)alkylmethicone copolyol sold by the company Dow Corning under the name Q25200;

- substituted or unsubstituted amino groups, such as the products sold under the names GP 4 Silicone Fluid and GP 7100 by the company Genesee or the products sold under the names Q2 8220 and Dow Corning 929 or 939 by the company Dow Corning. The substituted amino groups are, in particular, C1-C4 aminoalkyl groups;

- alkoxy groups such as the product sold under the name

Silicone Copolymer F-755 by SWS Silicones, and Abil Wax® 2428, 2434 and 2440 by the company Goldschmidt.

Preferably, the silicones used in the composition according to the invention are polyorganosiloxanes including one or more substituted or unsubstituted amino substituents.

In other words, the silicones used are preferentially chosen from amino-silicones.

For the purposes of the present invention, the term "amino silicone" means any silicone including at least one primary, secondary or tertiary amine function or a quaternary ammonium group.

The amino-silicones used in the cosmetic composition according to the present invention are chosen from:

(a) the compounds corresponding to the following formula (V):

(Rl)a(T)3-a-Si[OSi(T)2]n-[OSi(T)b(R ¹ )2-b]m-OSi(T)3-a-(R ¹ )a

(V)

in which,

T is a hydrogen atom or a phenyl, hydroxyl (-OH) or Ci-Cs alkyl substituent, and preferably methyl, or a Ci-Cs alkoxy, preferably methoxy,

a denotes the number 0 or an integer from 1 to 3, and preferably 0,

b denotes 0 or 1, and in particular 1, m and n are numbers such that the sum (n + m) can range especially from 1 to 2,000 and in particular from 50 to 150, it being possible for n to denote a number from 0 to 1 ,999 and in particular from 49 to 149, and for m to denote a number from 1 to 2,000 and in particular from 1 to 1 0;

Ri is a monovalent substituent having formula -C _q H2qL in which q is a number from 2 to 8 and L is an optionally quaternized amino group chosen from the following groups :

-N(R ² )-CH ₂ -CH ₂ -N(R ² )2 ;

-N(R ² ) ₂ ; -N ⁺ (R ² )3 Q ^" ;

-N ⁺ (R ² )(H) ₂ Q-;

-N ⁺ (R ² ) ₂ HQ-;

-N(R ² )-CH ₂ -CH ₂ -N+(R ² )(H) ₂ Q ,

in which R ² can denote a hydrogen atom, a phenyl, a benzyl or a saturated monovalent hydrocarbon-based substituent, for examp le a C i -C ₂ o alkyl substituent, and Q ^" represents a halide ion such as, for example, fluoride, chloride, bromide or iodide .

In particular, the amino-silicones corresponding to the definition having formula (V) are chosen from the compounds corresponding to the following formula:

(IV) in which R, R' and R", which may be identical or different, denote a C ₁ -C ₄ alkyl substituent, preferably CH ₃ ; a C ₁ -C ₄ alkoxy substituent, preferably methoxy; or OH; A represents a linear or branched, C3-C8 and preferably C3-C6 alkylene substituent; m and n are integers dependent on the molecular weight and the sum of which is between 1 and 2,000.

According to a first possibility, R, R' and R", which may be identical or different, represent a C1-C4 alkyl or hydroxyl substituent, A represents a C3 alkylene substituent and m and n are such that the weight-average molecular mass of the compound is between 5,000 and 500,000 approximately. The compounds of this type are named "amodimethicone" in the CTFA dictionary.

According to a second possibility, R, R' and R", which are identical or different, represent a C1-C4 alkoxy or hydroxyl substituent, at least one of the R or R" substituents is an alkoxy substituent and A represents a C3 alkylene substituent. The hydroxy/alkoxy mole ratio is preferably between 0.2/1 and 0.4/1 and advantageously equal to 0.3/1. Moreover, m and n are such that the weight-average molecular mass of the compound is between 2,000 and 10 ⁶ . More particularly, n is between 0 and 999 and m is between 1 and 1,000, the sum of n and m being between 1 and 1,000.

In this category of compounds, mention may be made, among others, of the product Belsil® ADM 652 sold by Wacker and the product Silsoft 253 by Momentive.

According to a third possibility, R and R", which are different, represent a C1-C4 alkoxy or hydroxyl substituent, at least one of the R and R" substituents is an alkoxy substituent, R' represents a methyl substituent and A represents a C3 alkylene substituent. The hydroxyl/alkoxy mole ratio is preferably between 1/0.8 and 1/1.1 and is advantageously equal to 1/0.95. Moreover, m and n are such that the weight-average molecular mass of the compound is between 2,000 and 200,000. More particularly, n is between 0 and 999 and m is between 1 and 1,000, the sum of n and m being between 1 and 1,000.

More particularly, mention may be made of the product Fluid WR® 1300 sold by Wacker.

According to a fourth possibility, R and R" represent a hydroxyl substituent, R' represents a methyl substituent and A is a C ₄ - Cs and preferably C ₄ alkylene substituent. Moreover, m and n are such that the weight-average mo lecular mass of the compound is between 2,000 and 10 ⁶ . More particularly, n is between 0 and 1 ,999 and m is between 1 and 2,000, the sum of n and m being between 1 and 2,000.

A product of this type is especially so ld under the name DC 28299 by Dow Corning.

It should be noted that the mo lecular weight of these silicones is determined by gel permeation chromatography (ambient temperature; polystyrene standard; μ styragem co lumns; eluent THF ; flow rate of 1 mm/m; 200 μΙ_, o f a 0.5 % by weight so lution o f silicone in THF are inj ected and detection is carried out by refractometry and UV spectrometry) .

A product corresponding to the definition having formula (V) is in particular the polymer known in the CTFA dictionary as Trimethylsilyl Amodimethicone, corresponding to formula (VI) below:

ChL ChL

I I

(CH ₃ ) ₃ SiO -SiO SiO - -Si(ChL 3)/3.

I I

ChL ChL

NH

m

(CH ₂ ) ₂

NH ₂

in which n and m have the meanings given above in accordance with formula (V) .

Such compounds are described, for example, in patent EP 95238 ; a compound having formula (VI) is so ld, for example, under the name Q2-8220 by the company OSI .

(b) the compounds corresponding to formula (VII) below :

in which,

, 3

R represents a monovalent Ci-Cis hydrocarbon-based substituent, and in particular a Ci-Cis alkyl or C ₂ -Cis alkenyl substituent, for example methyl,

R ⁴ represents a divalent hydrocarbon-based substituent, especially a Ci-Cis alkylene substituent or a divalent Ci-Cis, and for example Ci-Cs, alkylenoxy substituent;

Q ^" is a halide ion, especially chloride;

r represents a mean statistical value from 2 to 20 and in particular from 2 to 8;

s represents a mean statistical value from 20 to 200 and in particular from 20 to 50.

Such compounds are described more particularly in patent US 4,185,087.

A compound coming within this category is that sold by Union Carbide under the name Ucar Silicone ALE 56.

(c) the quaternary ammonium silicones having formula (XII):

in which:

R ₇ , which may be identical or different, represents a monovalent hydrocarbon-based substituent containing from 1 to 18 carbon atoms, and in particular a Ci-Cis alkyl substituent, a C ₂ -Cis alkenyl substituent or a ring containing 5 or 6 carbon atoms, for example methyl;

R ₆ represents a divalent hydrocarbon-based substituent, in particular a Ci-Cis alkylene substituent or a divalent Ci-Cis, for example Ci-Cs, alkyleneoxy substituent linked to the Si via an SiC bond;

Rs, which may be identical or different, represents a hydrogen atom, a monovalent hydrocarbon-based substituent containing from 1 to 18 carbon atoms, and in particular a Ci-Cis alkyl substituent, a C ₂ - Ci8 alkenyl substituent or a -R ₆ -NHCOR ₇ substituent;

X ^" is an anion, such as a halide ion, in particular chloride, or an organic acid salt (acetate, and the like);

r represents a mean statistical value from 2 to 200 and in particular from 5 to 100;

These silicones are described, for example, in Application EP- A-0530974.

d) the amino-silicones having formula (XIII):

(C _M H _2M )

NH ₂

in which:

- Ri, R ₂ , R ₃ and R ₄ , which may be identical or different, denote -C ₄ alkyl substituent or a phenyl group,

- R ₅ denotes a Ci-C ₄ alkyl substituent or a hydroxyl group,

- n is an integer ranging from 1 to 5,

- m is an integer ranging from 1 to 5, and in which x is chosen so that the amine number is between 0.01 and 1 meq/g.

The silicones that are particularly preferred in accordance with the invention are polysiloxanes containing amine groups such as amodimethicones or trimethylsilylamo dimethicones (CTFA, 4th edition, 1997), and even more particularly silicones containing quaternary ammonium groups such as silicones with the INCI name Quaterium-80.

When these compounds are used, one particularly advantageous embodiment involves their combined use with cationic and/or nonionic surfactants .

By way of examp le, it is possible to use the product sold under the name Cationic Emulsion DC 929 by the company Dow Corning, which comprises, besides amodimethicone, a cationic surfactant comprising a mixture of products corresponding to the formula:

CH,

I

R - N ⁺ — CH ₃ cf

CH ₃

in which R ⁵ denotes C 1 4-C ₂₂ alkenyl and/or alkyl substituents derived from tallow fatty acids and known under the CTFA name tallowtrimonium chloride, in combination with a nonionic surfactant having formula:

C ₉ H i ₉ -C ₆ H ₄ -(OC ₂ H ₄ ) i o-OH, known under the CTFA name Nonoxyno l 10.

Use may also be made, for example, o f the product sold under the name Cationic Emulsion DC 939 by the company Dow Corning, which comprises, besides amodimethicone, a cationic surfactant which is trimethylcetylammonium chloride and a nonionic surfactant having formula: C i 3 H27-(OC ₂ H ₄ ) i 2-OH, known under the CTFA name Trideceth- 12.

Another commercial product that may be used according to the invention is the product sold under the name Dow Corning Q2 7224 by the company Dow Corning, including, in combination, the trimethylsilyl amodimethicone having formula (C) described above, a nonionic surfactant having formula : C ₈ H i ₇ -CeH ₄ -(OCH ₂ CH ₂ )4o-OH, known under the CTFA name Octoxynol-40, a second nonionic surfactant having formula : C i ₂ H ₂₅ -(OCH ₂ -CH ₂ )6-OH, known under the CTFA name iso laureth-6, and propylene glycol.

Preferably, the silicones are chosen from amino-silicones having formula (IV) and amino-silicones having formula (XII) .

The silicones may be present in the composition according to the invention in a content ranging from 0.01 % to 20% by weight, preferably in a content ranging from 0. 1 % to 1 0% by weight and better still in a content ranging from 0.3 % to 5 % by weight relative to the total weight of the composition.

According to one embo diment, the composition according to the invention comprises (i) one or more fatty alcoho l ether type polyethoxylated nonionic surfactants having a melting point less than 35 °C, (ii) one or more fatty substances liquid at ambient temperature chosen from mineral oils, vegetable oils and mixtures thereo f, and (iii) one or more silicones, in particular amino -silicones.

In accordance with this embodiment, the fatty alcoho l ether type polyethoxylated nonionic surfactants preferentially have the formula (I) defined previously.

In accordance with this embodiment, the fatty substances are advantageously chosen from mineral oils .

In accordance with this embodiment, the fatty substances correspond to a mixture o f at least one mineral oil and at least one vegetable oil.

In accordance with this embodiment, the silicones are advantageously amino-silicones and preferentially meet the formula (IV) or formula (XII) .

The composition according to the invention generally comprises a total amount o f water ranging from 25 % to 95 % by weight, preferably ranging from 40% to 90% by weight and preferentially from 50% to 90% by weight, relative to the total weight of the composition. The composition according to the invention is presented in the form o f an oil-in-water nanoemulsion whose particles have preferably a number-average size less than 200 nm, preferentially comprised between 10 and 150 nm, and better between 20 and 100 nm, and even better between 25 and 90 nm, or even between 25 and 80 nm, even better between 25 and 75 nm.

The number-average size o f the particles (or oil drops) may be determined in particular according to the known method of quasi- elastic light scattering. As a machine that may be used for this determination, mention may be made of the Brookhaven brand machine equipped with an SX 200 optical bed (with a 532 nm laser) and a BI 9000 correlator. This machine gives a measurement of the mean diameter by photon correlation spectroscopy (PC S), which makes it possible to determine the numerical mean diameter from the polydispersity factor, which is also measured by the machine.

In addition, the composition according to the invention has very low polydispersity, i. e . the particles have very homogeneous size. The particles present in the composition according to the invention are liquid oil (or oil phase) particles inside the dispersing aqueous phase.

The composition in the form o f nanoemulsion may be characterized from the turbidity measurement according to the NTU method using the HACH Company model 21 OOP turbidimeter at ambient temperature (25 °C) . The turbidity o f the nanoemulsions of the invention is generally less than 400 NTU units, and preferably comprised between 1 0 and 250 NTU units, better still between 20 and 200 NTU units.

The pH o f the composition of the invention is generally between 3 and 8 , preferably between 4 and 7, better still between 5 and 6.

The composition according to the invention is advantageously presented in the form o f a transparent to milky fluid, preferably transparent to translucent.

The composition according to the invention may present a viscosity ranging for example 1 to 500 cPoises ( 1 to 500 mPa.s), and preferably from 1 to 200 cPoises ( 1 to 200 mPa.s), viscosity generally being measured (25 °C) with a Rheomat RM 1 80 (generally using spindle 1 or 2) .

The composition according to the invention may also contain additives such as cationic surfactants, cationic, anionic, nonionic, other than the fatty acid ether polyethoxylated nonionic surfactants according to the invention, or amphoteric po lymers, anionic surfactants, natural or synthetic polymeric thickening agents, anionic, amphoteric, zwitterionic, nonionic or cationic, associative or not, non- polymeric thickening agents such as electrolytes, styling polymers, agents for co louring keratin fibres, sugars, pearlizers, opacifiers, sunscreens, vitamins or provitamins, fragrances, colourants, organic or inorganic particles, preservatives, pH stabilization agents, sugars .

A person skilled in the art will take care to select the optional additives and the amount thereo f such that they do not harm the properties of the compositions of the present invention.

These additives are present in the composition according to the invention in an amount ranging from 0 to 50% by weight relative to the total weight of the composition.

Preferably, the composition according to the invention further comprises one or more cationic surfactants .

The cationic surfactants used in the composition may be chosen from salts o f optionally polyoxyalkylenated primary, secondary or tertiary fatty amines, and quaternary ammonium salts, and mixtures thereo f, quaternary esters (e. g. distearoylethyl hydroxyethylmonium methosulfate or dipalmitoylethyl hydroxyethylmonium methosulfate) .

Preferentially, the cationic surfactants are quaternary ammonium salts .

Examples of quaternary ammonium salts that may especially be mentioned include :

- those corresponding to the general formula (XIV) below: (XIV) in which the substituents Rs to Rn , which may be identical or different, represent a linear or branched aliphatic substituent including from 1 to 30 carbon atoms, or an aromatic substituent, such as aryl or alkylaryl, at least one of the substituents Rs to Rn denoting a linear or branched alkyl substituent including from 1 0 to 30 carbon atoms and X ^" denoting an inorganic or organic anion.

The aliphatic substituents may comprise heteroatoms such as, in particular, oxygen, nitrogen, sulfur and halo gens. The aliphatic substituents are, for examp le, chosen from C i _3 o alkyl, C i _3 o alkoxy, polyoxy(C2 - Ce)alkylene, C i _3 o alkylamide, (C i 2 - C22)alkylamido(C2 - C ₆ )alkyl and C i _3 o hydroxyalkyl substituents; X is an anion chosen from the group of the halides, phosphates, acetates, lactates, (C2 - C ₆ )alkyl sulfates, or alkyl- or alkylarylsulfonates .

Preference is given, among quaternary ammonium salts having formula (XIV), firstly, to tetraalkylammonium chlorides, such as, for example, dialkyldimethylammonium or alkyltrimethylammonium chlorides in which the alkyl substituent comprises approximately 12 to 22 carbon atoms, in particular behenyltrimethylammonium chloride, distearyldimethylammonium chloride, cetyltrimethylammonium chloride or benzyldimethylstearylammonium chloride, or alternatively, secondly, to palmitylamidopropyltrimethylammonium chloride or stearamidopropyldimethyl(myristyl acetate)ammonium chloride, so ld under the name Ceraphyl® 70 by Van Dyk.

Preferably, the cationic surfactants are tetraalkylammonium chloride.

Preferably, the composition according to the invention is free of nonionic ester-type surfactants . Preferably, the composition according to the invention is free of non-ionic ester type surfactants chosen from fatty acid ( C 8 - C 30 ) ester polyethyleneglyco l.

Preferably, the composition according to the invention as defined previously can be obtained by a phase inversion process (PIT) .

The present invention also relates to a preparation process for an oil-in-water type nanoemulsion comprising at least one fatty alcoho l ether-type polyethoxylated nonionic surfactant and at least one fatty substance having a melting temperature less than 35 ° C, by a phase inversion process (PIT) .

Preferably, the present invention relates to a preparation process for an oil-in-water type nanoemulsion comprising at least one fatty alcoho l ether-type polyethoxylated nonionic surfactant and at least one fatty substance having a melting temperature less than 35 °C , by a phase inversion process (PIT) and at least one silicone.

Preferably, the present invention relates to a preparation process for an oil-in-water type nanoemulsion comprising at least one fatty alcoho l ether type polyethoxylated nonionic surfactant and at least one fatty substance having a melting temperature less than 35 °C , by a phase inversion process (PIT) and at least one cationic surfactant.

The phase inversion process comprises the following steps :

(a) a step of mixing :

an oil phase including one or more fatty substances, and optionally liposo luble adjuvants that are stable at the phase inversion temperature,

one or more fatty alcoho l ether type polyethoxylated nonionic surfactants, and optionally a co-emulsifier. an aqueous phase containing water and optionally water- so luble so lvents and water-so luble adjuvants that are stable at the phase inversion temperature,

to produce an emulsion,

(b) a step o f heating said emulsion to a temperature within or above the phase inversion domain of 40 to 95 °C .

(c) a step of cooling the emulsion , and (d) optionally a step o f adding one or more additives, preferably one or more silicones, preferably amino-silicones or one or more compounds that are not stable at the phase inversion temperature such as fragrances .

The temperature domain for phase inversion during step (b) may be observed visually by observing changes in emulsion transparency and opacity, the emulsion being opaque when it is initially in the form o f a W/O emulsion, then transparent when it passes through a zone containing at least one microemulsion phase, the transparent appearance is retained when the system is cooled quickly below the phase inversion temperature.

This temperature domain may also be established, for a given composition, by measuring the conductivity o f a samp le o f the composition that is heated. When the phase inversion domain is approached, the conductivity o f the emulsion increases linearly until a temperature where its value drops sharply (o f a few orders o f magnitude) passing from a few hundreds of to a value o f almo st zero; this is the phase inversion domain. During the cooling step, after the phase inversion domain the conductivity falls linearly as a function of the temperature reduction.

Step (b) of the process can take place at a temperature that can range from 40 to 95 °C , preferably at a temperature ranging from 50 to 90°C, and more preferentially at a temperature ranging from 55 to 90°C .

The step (c) of the process may occur at a temperature that can range from 20 to 95 °C .

Specifically, step (c) is a step of quickly cooling the emulsion.

The rate of the cooling step (c) occurs at a rate that can range from 0. 1 to 30°C/min, preferably ranging from 0.2 to 25 °C/min.

The fatty substances are preferentially chosen from among oils.

The fatty substances in the very small droplets obtained by the process according to the invention are preferably not silicones . The term "non-silicone oil or fatty substance" means an oil or fatty substance not containing any Si-0 bonds and the term " silicone oil or fatty substance" means an oil or fatty substance containing at least one Si-0 bond.

The fatty substances present in the composition obtained by the process according to the invention are chosen from mineral oils , vegetable oils, liquid fatty alcoho ls, liquid fatty esters and mixtures thereo f.

The term " liquid fatty alcoho l" means a non-glycero lated and non-oxyalkylenated fatty alcoho l that is liquid at ordinary temperature (25 °C) and atmospheric pressure (760 mmHg; i.e . 1 .013 x l 0 ⁵ Pa) .

Preferably, the liquid fatty alcoho ls o f the invention include from 8 to 30 carbon atoms. The liquid fatty alcoho ls o f the invention may be saturated or unsaturated.

The saturated liquid fatty alcoho ls are preferably branched.

They may optionally comprise in their structure at least one aromatic or non-aromatic ring. They are preferably acyclic.

More particularly, the liquid saturated fatty alcoho ls o f the invention are chosen from octyldodecanol, isostearyl alcoho l and 2- hexyldecanol. Octyldodecanol is most particularly preferred.

The liquid unsaturated fatty alcoho ls contain in their structure at least one double or triple bond. Preferably, the fatty alcoho ls o f the invention bear in their structure one or more double bonds. When several double bonds are present, there are preferably 2 or 3 of them and they can be conjugated or unconjugated.

These unsaturated fatty alcohols may be linear or branched. They may optionally comprise in their structure at least one aromatic or non-aromatic ring. They are preferably acyclic.

More particularly, the unsaturated liquid fatty alcoho ls o f the invention are chosen from o leyl alcoho l, lino leyl alcoho l, lino lenyl alcoho l and undecylenyl alcoho l. Oleyl alcoho l is most particularly preferred.

The term "liquid fatty ester" means an ester that is derived from a fatty acid and/or from a fatty alcoho l and that is liquid at ordinary temperature (25°C) and at atmospheric pressure (1.013 ^χ 10 ⁵ Pa).

The esters are preferably liquid esters of saturated or unsaturated and linear or branched C1-C26 aliphatic mono- or polyacids and of saturated or unsaturated and linear or branched C1-C26 aliphatic mono- or polyalcohols, the total number of carbon atoms in the esters being greater than or equal to 10.

Preferably, for the esters of monoalcohols, at least one of the alcohol or of the acid from which the esters of the invention result is branched.

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

Esters of C4-C22 dicarboxylic or tricarboxylic acids and of Ci- C22 alcohols and esters of monocarboxylic, dicarboxylic or tricarboxylic acids and of non-sugar C ₄ -C26 dihydroxy, trihydroxy, tetrahydroxy or pentahydroxy alcohols may also be used.

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

The composition may also comprise, as liquid fatty ester, sugar esters and diesters of C6-C30 and preferably C12-C22 fatty acids. It is recalled that the term "sugar" means oxygen-bearing hydrocarbon- based compounds containing several alcohol functions, with or without aldehyde or ketone functions, and that comprise at least 4 carbon atoms. These sugars may be monosaccharides, oligosaccharides or polysaccharides. Examples o f suitable sugars that may be mentioned include sucrose (or saccharose), glucose, galactose, ribose, fucose, maltose, fructose, mannose, arabinose, xylose and lactose, and derivatives thereo f, in particular alkyl derivatives, such as methyl derivatives, for instance methylglucose.

The sugar and fatty acid esters may be chosen in particular from the group comprising the esters or mixtures o f sugar esters described previously and o f linear or branched, saturated or unsaturated C6 - C30 and preferably C 1 2 - C22 fatty acids. If they are unsaturated, these compounds may have one to three conjugated or unconjugated carbon-carbon double bonds.

The esters according to this alternative form can also be chosen from mono-, di-, tri- and tetraesters and polyesters, and mixtures thereo f.

These esters may be, for example, o leates, laurates, palmitates, myristates, behenates, cocoates, stearates, lino leates, lino lenates, caprates or arachidonates, or mixtures thereof such as, in particular, oleate/palmitate, oleate/stearate or palmitate/stearate mixed esters .

More particularly, use is made o f mono - and diesters and in particular mono- or di-o leate, -stearate, -behenate, -oleate/palmitate, - lino leate, -lino lenate or -oleate/stearate of sucrose, glucose or methylglucose.

An example that may be mentioned is the product sold under the name Glucate® DO by the company Amercho l, which is a methylglucose dio leate .

Preferably, the fatty substances used in the composition obtained by the phase inversion process are chosen from mineral oils, vegetable oils and mixtures thereof.

Preferably, the extra compounds added to step (d) may be chosen from cationic surfactants, glycols, polymers, silicones .

Preferentially, the compound added in step (d) is chosen from silicones, in particular amino-silicones.

More preferentially, the silicones are chosen from amino- silicones having formula (IV) or (XII) . The present invention also relates to a method for the cosmetic treatment of keratin fibres, in particular human keratin fibres such as hair, in which the composition according to the invention is applied to the said fibres .

Accordingly, an effective quantity o f the composition may be applied to keratin fibres fo llowed by an optional rinse after an optional waiting period.

Preferably, the treatment method comprises a rinsing step after the application o f the composition according to the invention.

The invention also relates to the use o f said composition for the cosmetic treatment of keratin fibres, particularly human keratin fibres such as hair.

The compositions according to the invention may be used, for example, as a cleaning composition, such as a pre-treatment or post- treatment composition for shampoos, dyes, permanent waves, bleaches and straighteners .

In a preferred manner, the composition according to the invention is a rinse-o ff or leave-on conditioner.

The present invention also relates to a treatment process for keratin substances, which consists in applying an effective amount of a composition as defined hereinabove to the keratin substances, and in optionally rinsing, for example after an optional leave-on time.

The examples that fo llow illustrate the present invention, and should not in any way be considered as limiting the invention.

EXAMPLES :

In the examples that fo llow, the amounts are given as mass percentages of active material relative to the total weight of the composition (AI : active ingredient) .

Example 1 :

A nanoemulsion is prepared by a PIT process Composition A:

Vegetable and/or mineral oil 17%

Oxyethylenated oleyl alcohol ( 10 EO) 15 %

Water qs 100%

Procedure :

Composition A is heated with stirring to about 90°C . The composition is then cooled quickly.

Result :

After two months o f storage at a temperature of 45 °C, the composition obtained is stable.

Example 2

The compositions B to D according to the invention and comparative compositions hereinafter are prepared by dilution, at 80 °C according to the protocol described in EP 1 ,430, 867 B l . The percentages are indicated on a weight basis .

Characterization :

The particle size is measured by dynamic light scattering (DLS) with a Malvern mo del Zetasizer Nano ZS particle size analyzer, equipped with a standard 4 mW power laser and at a wavelength λ o f 633 nm. The equipment is also equipped with a correlator (25 ns at 8 ,000 s, 4,000 channels max.) . The samp le temperature is regulated to 25 °C . The nanoemulsions have been previously diluted with Mili-Q water with a dilution ratio of 1 /5. The NNLS correlation function is used to analyse data.

The refraction indices for the scattered phases formulated are : n = 1 .465 for composition B, n = 1 .461 for composition C, n = 1 .456 for composition D and n = 1 .434 for the comparative composition. For each sample, three consecutive measurements were taken.

Results : It is observed that with the compositions according to the invention, it is possible to obtain a very small nanoemulsion.

In addition, compositions B and C have very low turbidity, o f the order of 40-50 NTU, whereas the comparative composition has much higher turbidity, greater than 200 NTU.