WO1999020241A1

WO1999020241A1 - Use of substantially amorphous cellulose nanofibrils associated with a polyhydroxylated organic compound in cosmetic formulations

Info

Publication number: WO1999020241A1
Application number: PCT/FR1998/002031
Authority: WO
Inventors: Claudie Willemin
Original assignee: Rhodia Chimie
Priority date: 1997-10-21
Filing date: 1998-09-22
Publication date: 1999-04-29
Also published as: FR2769836A1; JP2001520180A; AU746945B2; CN1280486A; EP1024782A1; CA2307321A1; KR20010031274A; BR9813118A; AU9269998A; FR2769836B1

Abstract

The invention concerns the use of substantially amorphous cellulose nanofibrils having a crystalline index not more than 50 % in dispersible dry form associated with at least a polyhydroxylated (polyOH) organic compound, as texturizing and/or reinforcing agent in cosmetic formulations. The invention further concerns the resulting cosmetic formulations.

Description

USE OF ESSENTIALLY CELLULOSE NANOFIBRILLES

AMORPHS ASSOCIATED WITH AT LEAST ONE ORGANIC COMPOUND

POLYHYDROXYL IN COSMETIC FORMULATIONS

The present invention relates to the use of essentially amorphous cellulose nanofibrils having a crystallinity rate less than or equal to 50% in a form dispersible in cosmetic formulations and to the formulations thus obtained.

The present invention more specifically relates to a new texturing and / or reinforcing agent for cosmetic formulations. For the purposes of the invention, the term “cosmetic formulation” means all the cosmetic products or preparations of the type of those described in Annex I ("Illustrative list by category of cosmetic products") of the European Directive n ° 76/768 / EEC of July 25, 1976, known as the Cosmetic Directive.

In general, cosmetic compositions are formulated in the form of a large number of types of products intended to be applied either to the hair, such as foams, gels (notably styling), conditioners, formulations for styling or to facilitate combing and / or disentangling of the hair, rinsing formulas, either on the skin such as hand and body lotions, products regulating the hydration of the skin, toilet milks, makeup-removing compositions, depilatory products, creams or lotions for protection against the sun and ultraviolet radiation, care creams, anti-acne preparations, local analgesics, make-up formulations of the mascaras type, foundations, nail polish products intended to be applied to the lips or other mucous membranes, sticks, solid compositions such as toilet soap and other formulations of the same type.

Conventionally, these different formulations incorporate, in addition to one or more active principles specific to the intended application, a certain number of so-called more conventional compounds which in particular have the function of giving them either prolonged stability over time (preservative for example) and / or a particular dosage form (such as gel, cream, milk, lotion for example). Generally, they are surfactants and / or dispersants, stabilizers, emulsifiers, humectants, gelling agents or even thickeners.

Mention may in particular be made of conventional stabilizers and / or thickeners, crosslinked polyacrylates, hydrocolloids obtained by fermentation such as Xanthane-Rhodicare gum and a succinoglycan such as Rheozan, cellulose derivatives such as hydroxypropylcellulose, carboxymethylcellulose, guars and their derivatives which are used alone or in combination. The object of the present invention is to propose a new texturing and / or reinforcing agent having an advantageous behavior in rheological terms for formulating the cosmetic compositions. More particularly, it is an agent based on cellulose nanofibrils, essentially amorphous having a crystallinity rate less than or equal to 50%, being in a dry form dispersible in an aqueous medium.

Generally speaking, native cellulose always comes in a fibrillar form. These fibrils are well known materials which are in particular already proposed for modifying the texture of the media into which they are introduced. In the case of fluid media, they modify their viscosities or even their rheological profiles.

The nanofibrils can be of various origins, for example of vegetable, bacterial, fungal, amoebic origin ...

In general, in plant fibers or walls there is a strong association between nanofibrils. Among the walls we can distinguish the secondary walls, mainly from wood, primary walls of which a typical example is the parenchyma. Examples of parenchyma consist of sugar beet pulp, citrus (lemons, oranges, grapefruit) and most fruits and vegetables. In the secondary walls, these fibrils are organized in the form of very oriented sheets thus forming an inseparable fiber. They are conventionally in the form of aggregates of a few tens of nanometers to a few micrometers. These aggregates consist of elementary fibrils which cannot be entangled, during their homogenization, without causing them to break.

In the context of the present invention, the cellulose fibrils under consideration are essentially amorphous cellulose nanofibrils (NFC) preferably obtained from cells with primary walls.

Advantageously, the cellulose nanofibrils of the invention come from cells made up of at least about 80% of primary walls, and preferably at least 85% by weight. Thus, the essentially amorphous cellulose nanofibrils used according to the invention preferably have at least 80% of cells with primary walls.

In contrast to the cellulose fibrils of secondary walls discussed above, the cellulose nanofibrils have a diameter of at most a few nanometers and have the appearance of filaments which prove to be disentangled during the homogenization stages. They preferably have a section of between approximately 2 and approximately 10 nm. More preferably, this is between approximately 2 and approximately 4 nm.

In the context of the invention, the nanofibrils considered are so-called essentially amorphous nanofibrils as opposed to so-called crystalline fibrils. By essentially amorphous is meant to define nanofibrils whose crystallinity rate is less than or equal to 50%. According to a particular variant of the present invention, this degree of crystallinity is between 15% and 50% and more preferably less than 50%. These essentially amorphous cellulose nanofibrils are particularly advantageous with regard to crystalline microfibrils in the sense that they are dispersible in aqueous media, confer very specific rheological properties of shear-thinning type and are stable either thermally or in environments with high ionic charges. . This good efficacy manifested, at a reduced dose, by the cellulose nanofibrils is in fact a consequence of their excellent rheological behavior in terms of flow threshold and shear-thinning power.

According to a preferred embodiment of the invention, the cellulose nanofibrils used according to the invention are loaded on the surface with carboxylic acids and acid polysaccharides, alone or as a mixture. By carboxylic acids is meant simple carboxylic acids, as well as their salts. These acids are preferably chosen from uronic acids and are more particularly galacturonic acid and / or glucuronic acid.

As acidic polysaccharides, mention may be made of pectins, more particularly polygalacturonic acids. These acidic polysaccharides can be present in mixture with hemicelluloses.

In fact, these surface-loaded nanofibrils do not result from a simple mixture between said nanofibrils and the acids and polysaccharides. Rather, it is a close combination of these two types of compounds derived directly from the process used to prepare nanofibrils. In fact, this preparation process can be such that the acids and polysaccharides are not completely separated from the fibers but remain on the surface of the latter, thus giving them very specific properties. It is important to emphasize that these same properties will not be reproduced if one proceeds successively to a complete separation of the nanofibrils from these acids and / or polysaccharides and then to an addition of the latter, to the nanofibrils thus obtained.

More specifically, the present invention relates to the use of these cellulose nanofibrils together with at least one polyhydroxylated organic compound (polyOH), in a redispersible solid form.

Consequently, the subject of the present invention is the use of essentially amorphous cellulose nanofibrils having a crystallinity rate of less than or equal to 50% in a dispersible dry form associated with at least one polyhydroxylated organic compound (polyOH), as texturing and / or reinforcing agent in cosmetic formulations. For the purposes of the present invention, a texturing agent is an agent having a stabilizing and thickening role in the cosmetic composition incorporating it.

In the context of the present invention, a reinforcing agent is an agent capable of improving the mechanical properties of the composition in which it is incorporated, both in the wet and in the dry state.

It was further observed that the combinations according to the invention could optionally be used as an emulsifying and stabilizing agent even in an aqueous medium containing surfactants.

The use of cellulose nanofibrils combined with at least one (polyOH) in dry form has not only an economic advantage, both in terms of storage and transport for example, but also from the technical point of view because with the redispersible dry form aqueous suspensions with a high content of dry active materials can be prepared.

Unexpectedly, the use of cellulose nanofibrils in this dry redispersible form as a texturing agent and / or as a reinforcement in cosmetic compositions has proved advantageous in several respects.

For example, in the particular case of cosmetic formulations intended for skin use of the cream type for example, there is a significant improvement in the level of skin penetration of said formulations. No phenomenon of "soaping" is observed on the surface of the skin at the time of the application of these formulations. Finally, the cellulose nanofibrils according to the invention give a very soft skin feel as well as a tightening and protective effect on the skin surface, as well as a moisturizing effect.

With regard to the particular case of hair formulations, the incorporation of cellulose nanofibrils associated with at least one polyhydroxylated organic compound strengthens the styling effect.

The use of said combination with a water-soluble film-forming polymer in solution or a film-forming polymer insoluble in water in dispersion, leads to the production of a film-forming material having good adhesion on keratinous support with a cosmetic feel that is neither greasy nor sticky. .

The water-soluble film-forming polymers used in accordance with the present invention can be:

- Or a water-soluble synthetic film-forming polymer with a low glass transition temperature Tg, preferably less than or equal to 20 ° C; - or a water-soluble film-forming polymer of natural origin (polysaccharide derived from cellulose) with a high Tg generally greater than or equal to 40 ° C. Mention may be made, for example, of polyvinyl alcohol, hydroxyethylcellulose, the cellulose ethers generally used in cosmetics, guar gums, locust bean gums.

Similarly, unlike conventional thickeners, the cellulose nanofibrils according to the invention do not affect the cosmetic properties of the formulations incorporating them. Advantageously, no braking effect or loss of gloss is noted and no reduction in the water persistence of the compositions is observed.

In addition, a fragrance-enhancing effect has been highlighted. As mentioned above, the association with cellulose nanofibrils of at least one (polyOH), operated during the process for preparing cellulose nanofibrils, has the advantage of allowing their formulation in a dispersible dry form. This is, of course, of potential interest for the preparation of the corresponding cosmetic formulations, in particular that of offering greater flexibility of formulation due to the high content of active ingredient.

The polyhydroxy organic compound (polyOH) is preferably chosen from carbohydrates and their derivatives and polyalcohols.

As a representative of these carbohydrates, mention may be made particularly of linear or cyclic monosaccharides in C-3 to C-6, and preferably in C-5 or C-6, for example fructose, mannose, galactose, sucrose, talose, gulose, allose, altrose, idose, arabinose, xylose, lyxose and ribose, oligosaccharides, for example maltose and lactose, polysaccharides, for example starch, cellulose, xanthan gum and guar, and their fatty derivatives such as fatty acid sucroesters, alcohol carbohydrates, for example sorbitol and mannitol, acid carbohydrates, for example gluconic acids, uronic, galacturonic as well as their salts and the ether carbohydrates, for example methyl-, ethyl-, carboxymethyl-, hydroxyethyl- and hydroxypropyl-ethers of cellulose.

As regards the polyalcohols, they may especially be glycerol, pentaerythrol, propylene glycol, ethylene glycol and / or polyvinyl alcohols. In the particular case of carbohydrates and their derivatives, used in conjunction with essentially amorphous cellulose nanofibrils, mention may more particularly be made of carboxylated celluloses and preferably carboxymethylated cellulose, also designated by CMC.

Cellulose is a polymer made up of monomeric glucose units: the degree of polymerization can vary within wide limits. The carboxylated group is introduced therein in a manner known per se, by reacting chloroacetic acid with cellulose. Its degree of substitution then corresponds to the number of carboxymethyl groups per unit of glucose. The maximum theoretical degree of substitution is of 3. These carboxylated celluloses are said to have a high degree of substitution for a value greater than 0.95 and of low degree for a value less than this.

Thus, carboxymethylated celluloses of high masses are suitable, the content of carboxylated cellulose retained then being greater than or equal to 5% by weight and less than or equal to 30% by weight, or carboxymethylated celluloses of low masses, the content of carboxylated cellulose being in this case, more particularly between 10 and 30% by weight.

At identical mass, it also appears possible to further reduce the proportion compared to nanofibrils, by favoring the choice of a carboxymethylated cellulose with a high degree of substitution.

Such mixtures of cellulose nanofibrils and carboxylated cellulose are in particular described in applications PCT / FR 97 01 291 published under the number WO 98/02487 and PCT / FR 97 01290 published under the number WO 98/02486.

Preferably, this polyhydroxy organic compound (polyOH) is chosen from carboxymethylcellulose, xanthan gum, guar, sorbitol, sucrose and their mixtures.

The cosmetic formulations obtained according to the invention preferably comprise the polyhydroxylated compound (s) and the cellulose nanofibrils in a weight ratio (polyOH) x 100 / [(polyOH) + (NFC)] greater than or equal to 5% and less or equal to 50% and preferably greater than or equal to 5% and less than or equal to

30 %.

According to a preferred embodiment of the invention, they comprise cellulose nanofibrils in a form associated with carboxymethylcellulose (CMC) of high degree of substitution in a weight ratio (CMC) x 100 / [(CMC) + (NFC)] greater than or equal to 5% and less than or equal to 25%.

Another polyhydroxylated derivative, such as sucrose, propylene glycol or polyethylene glycol, for example, can also be combined with CMC. In this particular case, the weight ratio (CMC) x 100 / [(polyOH) t ₀ t _a | + (NFC)] is then lowered significantly. With regard to the amounts of cellulose nanofibrils and (polyOH), which can be used according to the invention, it is clear that they are a function of the type of dosage form targeted and / or of the desired effect at the level of the cosmetic formulation, for example, strengthening a hydrating effect or even providing a protective effect on the epidermis as in depilatory formulations. Thus in galenic forms of the cream type will be present greater amounts of texturing agent according to the invention compared to those used in formulations of the fluid type. Preferably, the amount of mixture of cellulose nanofibrils and polyOH (s) is adjusted so that said nanofibrils are present in an amount of approximately 0.1 to 20% and, more preferably, approximately 0.15 and 5 % by weight of the cosmetic formulation. By way of illustration, it is possible to propose, for the preparation of the cream-type formulations, a concentration of cellulose nanofibrils and (polyOH) varying between 0.1 1 and 40%, and for the fluid-type formulations, a concentration of between 0.11 and 10%. The values are proposed for a weight ratio (polyOH) x 100 / [(polyOH) + (NFC)] greater than or equal to 5% and less than or equal to 50%.

The solid redispersible composition of cellulose nanofibrils, used according to the invention, may contain, in addition to the organic compound (s) polyhydroxylated (s) defined above, at least one co-additive chosen among:

• the compounds of formula (R ¹ R ² N) COA, in which R ¹ or R ² , which are identical or different, represent hydrogen or a C 1 to C 10 alkyl radical, preferably C 1 to C-5, A represents hydrogen, a C-1 to C alkyl radical

10, preferably at C-1 to C-5, or alternatively the group R'1R ' ² N with R "i, R'2, identical or different, representing hydrogen or a C-1 to C alkyl radical -

10, preferably at C-1 to C-5; and ^» anionic, nonionic or amphoteric surfactants, these co-additives can be used alone or as a mixture.

Mention may in particular be made, as representative of these surfactants, of those identified below in the text.

Note that the use of these co-additives makes it possible, in combination with (polyOH) such as, for example, carboxymethylcellulose, to reinforce the shear-thinning profile of the cellulose nanofibrils, after redispersion.

As regards the compounds of the (R ¹ R ² N) COA type, it is preferred to use the compounds comprising two amide functions. Preferably, urea is used as a co-additive. According to a particular embodiment of the invention, these solid redispersible compositions of essentially amorphous cellulose nanofibrils comprise carboxylated cellulose with a high degree of substitution and as co-additive at least one compound chosen from surfactants.

When the cellulose nanofibrils used according to the invention are combined with one or more polyhydroxy compounds and with one or more aforementioned co-additive (s), the content of polyhydroxylated compound (s) and co-additive (s) ) is greater than or equal to 5% by weight and less than or equal to 30% by weight relative to the weight of nanofibrils, polyhydroxylated compound (s) and co-additive (s). The nanofibrils used according to the invention can be obtained from various methods, already described in the literature.

In particular, reference may be made to the process described in European patent application EP-A-726 356. The treatment is carried out there on the pulp of plants with primary walls, namely moist, dehydrated pulp, preserved by silage or partially depectinate, such as for example beet pulp, after it has undergone a step of prior extraction of sucrose, according to methods known in the art. More specifically, this treatment uses a first acid or basic extraction, at the end of which a first solid residue is recovered, optionally followed by a second extraction, carried out under alkaline conditions, of the first solid residue, the recovery of '' a second solid residue, washing and then bleaching the two residues of cellulosic material together, diluting the third solid residue obtained at the end of the bleaching step, then diluting the resulting suspension, so as to obtain a dry matter content of between 2 and 10% by weight, and finally a homogenization step, comprising, at least one cycle of the diluted suspension.

This homogenization step corresponds to any mixing, grinding or any high mechanical shearing operation, followed by one or more passages of the cell suspension through a small diameter orifice, subjecting the suspension to a drop of pressure of at least 20 mPa and a shearing action at high speed followed by a deceleration impact at high speed. The homogenization of the cellulosic suspension is obtained by a number of passages which can vary between 1 and 20, preferably between 2 and 5, until a stable suspension is obtained.

With regard to the detailed protocol for each of the stages of this processing, reference is made to the description of the request identified above.

The process which has just been described makes it possible to obtain nanofibrils which conserve on their surface carboxylic acids and / or polysaccharides. In the case of the cellulose nanofibrils used according to the invention, a polyhydroxylated compound of the type, for example carboxylated cellulose, is introduced into the preparation protocol described above, either before the implementation of the homogenization step or after that a homogenization cycle has been operated.

It should be noted that this variant of the process is described in the international patent application number PCT / FR 97/01291 published under the number WO 98/02487, to which reference may be made if necessary.

The process for the preparation of cellulose nanofibrils, additivated with polyhydroxylated compound (s), consists, in a first step, in adding to the suspension of nanofibrils, possibly having undergone at least one homogenization cycle, at least part of the polyhydroxylated compound considered and optionally of the co-additive (s). Then, in a second step, a step of drying the suspension thus added is implemented. In fact, the addition of at least part of the polyhydroxylated compound and optionally of the co-additive (s) can be carried out according to three variants:

either at the end of the homogenization step and according to a preferred mode, after the latter has undergone at least one concentration step,

- either to the suspension at the end of the homogenization step, before the latter has undergone at least one concentration step, or

- before or during the homogenization step, the pulp having then undergone at least one cycle of the homogenization step.

The concentration stage or stages can be carried out by any conventional means until a dry extract of approximately 35% by weight is obtained. More particularly, the dry extract is between 5 and 25% by weight.

Prior to the actual drying step, it may be advantageous to carry out shaping, namely by extrusion or granulation, of the suspension which has been concentrated. The temperature of the drying step is of course retained so as to limit any degradation of the carboxylic acids, acid polysaccharides, hemicelluloses, polyhydroxy compounds and, if appropriate, co-additives. It is more particularly between 30 and 80 ° C., preferably between 30 and 60 ° C.

The drying step, carried out by conventional means, is carried out so as to maintain at least 3% by weight of water relative to the weight of the solid produced. More particularly, the weight of water maintained is between 10 and 30% by weight. Such an implementation makes it possible not to exceed the threshold beyond which the redispersion of the nanofibrils can no longer be complete.

Advantageously, the suspension of cellulose nanofibrils obtained by redispersion in water of the mixture, obtained according to the protocol described above, has a viscosity level corresponding to at least 50% for a shear rate of at least 1 s ~ 1, the viscosity level of a suspension of cellulose nanofibrils which have not undergone a drying step and which do not comprise a polyhydroxylated compound or co-additives.

Of course, the essentially amorphous cellulose nanofibrils charged at the surface, preferably in acid, and associated with a polyhydroxylated compound and optionally with a co-additive are used in the cosmetic formulations obtained according to the invention, in admixture with at least one vehicle compatible with hair, skin or sun application. The term "compatible" with an application to the hair and / or the skin means here that this vehicle does not damage or exert a negative effect on the appearance of the hair and / or the skin or does not create a skin and / or eye and / or scalp irritation. The present invention also relates to cosmetic formulations using as texturing agent and / or reinforcement of cellulose nanofibrils essentially amorphous in a dry dispersible form and associated with at least one polyhydroxylated organic compound as defined above. These formulations can also contain an additive as defined above. Preferably, the cosmetic formulations in accordance with the invention use a vehicle, or a mixture of several vehicles, present in said formulations at concentrations of between 0.5 and 99.5% approximately and more preferably between 5 and Around 90%.

The vehicles compatible with the formulations according to the invention include, for example, those used in sprays, foams, tonics, gels, shampoos, or even rinsing lotions.

Of course the choice of the appropriate vehicle depends on the specific application targeted by the formulation. A vehicle suitable for a formulation intended to remain on the surface to which it has been applied (for example spray, foam, lotion, tonic or gel), will not be the suitable vehicle for a formulation to be rinsed off after use (for example shampoo conditioner, rinse lotion).

The vehicles capable of being used can therefore be simple or complex and include a large number of products usually used in cosmetic formulations intended for hair, skin or sun use. It can thus be water optionally supplemented with a solubilizer to dissolve or disperse the active ingredients used, such as the alcohols C-1 to C-6, and their mixtures, in particular ethanol, isopropanol or propylene glycol, and their mixtures.

Advantageously, there is good compatibility of the cellulose nanofibrils associated with at least one polyhydroxylated organic compound with regard to alcohol-type solubilizers. The texturing properties of these cellulose nanofibrils are not altered in hydroalcoholic media.

Similarly, they retain their properties in so-called more aggressive media, either very acidic such as α-hydroxyacid creams or alkaline media such as depilatory formulations or lotions for perms.

Examples 2 and 3 presented below give an account of this advantageous behavior of the cellulose nanofibrils associated with at least one polyOH in cosmetic application. Advantageously, the NFCs formulated according to the invention prove to be excellent structuring agents for cosmetic media and retain their properties over time. Their viscosity is higher than that of microcrystalline celluloses.

It is also possible to combine, in a fatty phase distinct from the aqueous phase of the NFCs according to the invention, one or more emollients chosen from: oils

(5) minerals (such as Marcol 82), vegetable or marine oils, halogenated hydrocarbons, linalool, esters (such as isopropyl myristate), and silicones compatible with a cosmetic application (in particular cyclodimethicones and dimethicones and derivatives and hexamethyldisiloxane) and their derivatives or mixtures.

When the cosmetic formulations are in the form of sprays, tonic lotions, gels, or foams, the preferred solvents include water, ethanol, volatile silicone derivatives, and mixtures thereof. The solvents used in these mixtures can be miscible or immiscible with each other. Foams and aerosol sprays can also use any propellant capable of generating the products in the form of foam or fine, uniform sprays. By way of examples, mention may be made of dimethyl ether, propane, n-butane, or isobutane.

In the case where the cosmetic formulations are intended for topical local application, the vehicles must have good edonic properties, be compatible with all the other components, and have perfect safety.

These vehicles can take a large number of forms, of emulsion type, foams, sprays, etc. For example, vehicles in the form of emulsions include water in silicone, water in oil, oil in water, and oil in water in emulsions. silicone. These emulsions cover a wide viscosity range, for example from 100 to 20,000 mPa.s at 25 ° C. These emulsions can also be delivered in the form of sprays using either a device of the mechanical pump type, or pressurized by the use of a propellant gas.

These vehicles can also be delivered in the form of foam.

In addition to the vehicles identified above, the cosmetic formulations according to the invention may contain surfactants, used to disperse, emulsify, dissolve and stabilize various compounds used in particular for their emollient or moisturizing property. They can be of the anionic, nonionic, cationic, zwitterionic or amphoteric type. By way of illustration of these compounds, there may be more particularly mentioned: - anionic surfactants such as alkyl esters sulfonates, alkyl sulfates, alkylamide sulfates and salts of saturated or unsaturated fatty acids; - nonionic surfactants such as polyoxyalkylenated alkylphenols, glucosamides, glucamides, glycerolamides derived from N-alkylamines, aliphatic alcohols C-8 to C-22 polyoxyalkylenated, products resulting from the condensation of oxide d ethylene with a hydrophobic compound or resulting from the condensation of propylene oxide with propylene glycol, amine oxides, alkylpolyglycosides and their polyoxyalkylenated derivatives, C-8 to C-20 fatty amides and fatty acids , ethoxylated amides, amines, amidoamines;

- amphoteric and zwitterionic surfactants such as those of betaine type such as betaines, sulfo-betaines, amidoalkylbetaines and sulfo-betaines, alkylsultaines, condensation products of fatty acids and protein hydroxylates, cocoamphoacetates and cocoamphodiacetates, alkylamphopropionates or -dipropionates, amphoteric derivatives of alkylpolyamines. Conditioners may also be present.

Among these, there may be mentioned those of synthetic origin better known under the name polyquaternium such as polyquaterniums -2, -7, and -10, cationic derivatives of polysaccharides, such as cocodimonium hydroxyethyl cellulose, guar hydroxypropyl trimonium chloride, hydroxypropyl guar hydroxypropyl trimonium chloride, non-volatile silicone derivatives such as amodimethicone, cyclomethicones, non-water-soluble and non-volatile organopolysiloxanes such as oils, resins or gums such as diphenyldimethicone gums.

Cosmetic formulations can also contain polymers having film-forming properties which can be used to provide a fixing function. These polymers are generally present at concentrations of between 0.01 and 10%, preferably between 0.5 and 5%. They are preferably of the polyvinylpyrrolidone type, polyvinylpyrrolidone and methyl methacrylate copolymers, polyvinylpyrrolidone and vinyl acetate copolymer, polyerephthalene glycol / polyethylene glycol copolymers, sulfonated terephthalic copolyester polymers.

Cosmetic formulations can also contain polymeric derivatives exerting a protective function, in amounts of the order of 0.01 to 10%, preferably approximately 0.1 to 5% by weight, derivatives such as cellulose derivatives, grafted polyvinyl esters on polyalkylene skeletons, polyvinyl alcohols, sulfonated terephthalic copolyester polymers, ethoxylated monoamines or polyamines and polymers of ethoxylated amines.

Hydrating agents can also be incorporated into cosmetic formulations. By way of illustration of the latter, mention may in particular be made of glycerol, propylene glycol, urea, collagen, gelatin, and emollients which are generally chosen from alkylmonoglycerides, alkyldiglycerides, triglycerides such as oils extracted from plants and plants or their hydrogenated derivatives, mineral oils or paraffinic oils , diols, fatty esters, silicones.

To these compounds, one or more perfumes, coloring agents and / or opacifying agents such as pigments are generally added.

To protect the skin and / or the hair from the aggressions of the sun and UV rays, we can add to these formulations sunscreens which are either organic compounds strongly absorbing UV radiation or mineral particles in nanoparticulate state, like l zinc oxide, titanium dioxide or cerium oxides.

Active ingredients, such as vitamins, α-hydroxy acids, plant derivatives, marine extracts, with purely cosmetic properties, can be incorporated into the formulations containing NFCs for a treating action. Similarly, NFCs are preferred texturing agents for depilatory formulations such as media based on calcium thioglycolate, for example.

Preservatives such as esters of p-hydroxybenzoic acid, sodium benzoate, or any chemical agent preventing bacterial proliferation or molds and traditionally used in cosmetic compositions are generally introduced into these compositions up to 0.01 to 3% by weight in accordance with Annex VII of the cosmetic regulations.

Finally, cosmetic formulations can also contain viscous or gelling polymers such as crosslinked polyacrylates of the CARBOPOL® type marketed by GOODRICH, cellulose derivatives such as hydroxypropylcellulose, carboxymethylcellulose, guars and their derivatives such as hydroxypropyl guar such as Jaguar HP®, carob, tara or cassia gum, xanthan gum such as Rhodicare®, succinoglycans, alginates, carrageenans, chitin derivatives or any other polysaccharide with texturing function. It is clear that the choice of these so-called conventional compounds and the appreciation of their respective amounts are directly linked to the type of formulation envisaged, namely gel, cream, milk, spray, lotion ... and to the edonic character sought. These adjustments are in fact routine operations for the cosmetic formulator. The cosmetic formulations according to the invention can be advantageously used in the hair, sun care, body care and make-up fields.

The examples submitted below are presented simply by way of illustration and without limitation of the present invention. EXAMPLE 1

Preparation of a mixture of cellulose nanofibrils and carboxymethylcellulose.

A carboxymethylcellulose, with a degree of substitution equal to 1, 2 (CMC BLANOSE

12M8P from AQUALON) is dissolved in distilled water. The solution is then added to the mother dispersion of nanofibrils containing 2.3% of cellulose nanofibrils and prehomogenized with Ultra-Turrax at 14,000 rpm (1 min for

100 g of dispersion). The whole is agitated with a pale deflocculator at 1000 rpm for

30 mins.

The amount of carboxymethylcellulose added is 15% by weight, relative to the weight of cellulose nanofibrils and of carboxymethylcellulose.

The mixture is then poured into cups and then dried either in a ventilated oven at 40 ° C, to a dry extract of 92%, controlled by dosing water with the KARL-FISCHER method.

The dried mixture is then ground, then sieved through a 500 μm sieve. The powder obtained is redispersed in an amount of 0.43% by weight of cellulose nanofibrils and of carboxymethylcellulose in distilled water. The agitation is carried out with a deflocculating paddle at 1000 rpm for 5 min or 30 min. This dispersion is implemented in the examples below.

EXAMPLE 2

Behavior of NFC associated with CMC in alcoholic environment.

To do this, the NFC / CMC mixture prepared in Example 1 is dispersed in water, under shearing, then the alcohol in question is added or not.

Table I presented below gives an account of the composition of the two hydroalcoholic media thus prepared. The viscosities of these media and of a control medium (water) are evaluated using a viscometer of the BROOKFIELD LVT type. The results are shown in Table I.

TABLE I

EXAMPLE 3

Behavior of NFC associated with CMC in an acidic or alkaline medium.

The NFC mixture prepared according to Example 1 is introduced into water buffered to a pH of 4 or 9. The rheological behavior of this medium is assessed with regard to a control medium comprising 1% of microcrystalline celluloses with CMC additives . Table II reports the change in viscosity over time.

ΓABLEAU H

It should be noted that the NFCs formulated according to the invention prove to be excellent structuring agents for cosmetic media and retain their properties over time. Their viscosity is higher than that of microcrystalline celluloses. EXAMPLE 4 Cosmetic formulations according to the invention.

These formulations contain the NFC / CMC mixture prepared in Example 1. 1) Cream with α-hydroxy acids

Ingredients% by weight

Phase A ^α Cetearyl alcohol 8

° Diethylamine cetety phosphate 2

^D Eicosene / PVP 2 copolymer

^D Octyldodecyl neopentanoate 10

° Mirasil DM 300: Dimethicone 1 Phase B

° NFC / CMC 0.2

° Propylene glycol 5 ^α Water qs 100

Phase C

° Alpha hydroxy acids

Phase D ^π Triethanolamine 1, 8

Phase E

° Preservative q.s.

2) Gentle body scrub

Ingredients% by weight

Phase A

° Water q.s. 100

Phase B

° NFC / CMC 1

Phase C ^π Magnesium lauryl sulfate 8.5 ^α Sodium cocoyl sarcosinate 1.0

° 55% sodium hydroxide 0.50

° Diethylamine Lauramide 2.0

° Stearic acid 1, 0

® ° Géropon AC78: sodium cocoyl isethionate 13

Phase D

° Polyethylene oxide 20

Phase E

° Preservative q.s.

° Perfume and coloring q.s.

3) depilatory lotion

Ingredients% by weight

Phase A ^α NFC / CMC 0.5

° Water q.s. 100

Phase B

° Propylene glycol

Phase C ^D Mineral oil and lanolin alcohol 5

^D Polysorbate 80 and cetyl acetate and acetylated lanolin alcohol 2

^D PEG-100 stearate and glyceryl stearate 2 Phase D ^π Calcium thioglycolate 5

^D Calcium hydroxide 6

Phase E

^D Preservative, colorant, perfume qs 100

EXAMPLE 5

Behavior of NFCs associated with CMC as a reinforcing agent for a film-forming polymer dispersion

The purpose of this example is to show that the association of nanofibrils with at least one (polyOH) can also be a reinforcing agent.

The tests were carried out with a film-forming latex Rhodopas DS 1003 sold by Rhodia (aqueous dispersion of acrylic polymer), whose glass transition temperature Tg is 12 ° C, the film forming temperature

TMF below 5 ° C, the dry extract of the dispersion is 50%, and the particle size of said latex is 0.1 μm. The dispersion has a pH of approximately 8.

The dispersion of cellulose nanofibrils obtained in Example 1 from the dry powder is used in this example.

Formulation that can be used as a base for aqueous nail polish

Two DS 1003 latex-based formulations as defined above are prepared:

F1 (comparison): 30% by weight of latex 1003 + 70% by weight of water, relative to the total weight of the formulation;

F2 (according to the invention): 30% by weight of latex 1003 + 1% by weight of NFC obtained in Example 1 + 69% by weight of water, relative to the total weight of the formulation. The pH of the medium is adjusted to 7.

F1 has a viscosity of less than 10 mPa.s while the viscosity of F2 is around 4500 mPa.s. The viscosities are evaluated using a viscometer of the type

BROOKFIELD LVT (needle 3, 10 rpm).

The results are summarized in Table III. Table III

Persoz hardness is determined according to standard NFT 30-016: hardness is measured after more than 8 days of ambient drying at 3 different places on the plate. Each measurement corresponds to the average of 3 measurements. The results indicate the time (in seconds) that the pendulum takes to dampen its oscillation from an angle of 12 ° to an angle of 4 °.

The longer the time, the harder the film.

The adhesion on a support is determined by a grid test according to ISO 2409 standard: the films were drawn on a steel plate. The test consists of using a cutter to criss-cross the film with 2 series of 6 perpendicular lines spaced 1 mm apart and to tear off this grid with adhesive tape. The note goes from 0 (no tearing) to 4 (tearing about 50% of the grid).

The formulation F2 which includes the NFC additives of the invention therefore corresponds to a material which could serve as a base for aqueous varnish. The F2 formulation obtained is stable. Of pseudo-plastic character, it spreads easily on the supports. The film has good adhesion and good flexibility with a touch that is neither greasy nor sticky.

Claims

1. Use of essentially amorphous cellulose nanofibrils having a crystallinity rate less than or equal to 50% in a dispersible dry form associated with at least one polyhydroxylated organic compound (polyOH), as texturing agent and / or reinforcement in cosmetic formulations.

2. Use according to claim 1 characterized in that the polyhydroxylated organic compound (polyOH) is chosen from carbohydrates and their derivatives and polyalcohols.

3. Use according to claim 2 characterized in that the carbohydrates are preferably chosen from linear or cyclic C-3 to C-6 monosaccharides, oligosaccharides, polysaccharides and their fatty derivatives such as fatty acid sucroesters, carbohydrates alcohol, acids and ethers.

4. Use according to one of claims 1 to 3, characterized in that the polyhydroxy organic compound (polyOH) is preferably chosen from carboxymethylcellulose, xanthan gum, guar, sorbitol, sucrose and their mixtures.

5. Use according to one of claims 1 to 4, characterized in that the degree of crystallinity is between 15 and 50% and preferably less than 50%.

6. Use according to one of claims 1 to 5 characterized in that the cellulose nanofibrils have at least 80% of cells with primary walls.

7. Use according to one of claims 1 to 6 characterized in that the cellulose nanofibrils come from cells preferably consisting of at least about 80% of primary walls.

8. Use according to one of claims 1 to 7, characterized in that the cellulose nanofibrils are loaded with carboxylic acids and with acid polysaccharides, alone or as a mixture.

9. Use according to one of claims 1 to 8 characterized in that the polyhydroxylated organic compound is associated with the cellulose nanofibrils in a ratio by weight (polyOH) x 100 / [(polyOH) + (NFC)] greater than or equal to 5% and less than or equal to 50%.

10. Use according to claim 9 characterized in that the weight ratio (polyOH) x 100 / [(polyOH) + (NFC)] is greater than or equal to 5% and less than or equal to

30 %.

11. Use according to one of claims 4 to 10 characterized in that the cellulose nanofibrils are associated with carboxymethylcellulose (CMC) of high degree of substitution in a weight ratio (CMC) x 100 / [(CMC) + (NFC)] greater than or equal to 5% and less than or equal to 25%.

12. Use according to one of the preceding claims, characterized in that the amount of mixture of cellulose nanofibrils and (polyOH) (s) is adjusted so that said nanofibrils are used in an amount of 0.1 to 20% by weight of the cosmetic formulation.

13. Use according to claim 12, characterized in that the nanofibrils are used in an amount of 0.15 to 5% by weight.

14. Use according to one of the preceding claims, characterized in that the cellulose nanofibrils and the (polyOH) are associated with at least one co-additive chosen from:

• the compounds of formula (R ¹ R ² N) COA, in which R ¹ or R ² , which are identical or different, represent hydrogen or a C 1 to C 10 alkyl radical, preferably C 1 to C-5, A represents hydrogen, an alkyl radical in C-1 to C-10, preferably in C-1 to C-5, or also the group R "IR ' ² N with R' ¹ , R ' ² , identical or different, representing hydrogen or a C-1 to C-10 alkyl radical, preferably C-1 to C-5, and • anionic, nonionic or amphoteric surfactants, these co-additives can be used alone or as a mixture.

15. Use according to claim 14 characterized in that the content of polyhydroxy compound (s) and co-additive (s) is greater than or equal to 5% by weight and less than or equal to 30% by weight relative by weight in nanofibrils, polyhydroxylated compound (s) and in co-additive (s).

16. Cosmetic formulation characterized in that it comprises, as texturing agent and / or reinforcement, cellulose nanofibrils essentially amorphous in a dry dispersible form and associated with at least one polyhydroxylated organic compound, as defined according to one of claims 1 to 13 and, where appropriate, at least one additive according to claim 14 or 15.