AU746945B2 - Use of substantially amorphous cellulose nanofibrils associated with a polyhydroxylated organic compound in cosmetic formulations - Google Patents

Description

1 USE OF ESSENTIALLY AMORPHOUS CELLULOSE NANOFIBRILS COMBINED WITH AT LEAST ONE POLYHYDROXYLATED

ORGANIC

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

A more specific subject-matter of the present invention is a novel •texturizing and/or strengthening agent for cosmetic formulations.

n .nwa Any discussion of the prior art throughout the specification should 0 1 in no way be considered as an admission that such prior art is widely known or .forms part of common general knowledge in the field.

Within the meaning of the invention, the term "cosmetic formulation" is understood to mean any cosmetic product or preparation of the type of those described in Appendix I ("Illustrative list by category of cosmetic 15 products") of the European Directive No. 76/768/EEC of 25 July 1976, known as the Cosmetics Directive.

Cosmetic compositions are generally formulated inthe form of a large number of product types intended to be applied either to the hair, such as foams, gels (in particular styling gels), conditioners, formulations for styling or for facilitating the combing and/or the disentangling of the hair, or rinsing formulae, or to the skin, such as hand and body lotions, products which regulate the moisturization of the skin, cleansing milks, make-up removing compositions, depilatory products, creams or lotions for protecting against the sun and ultraviolet radiation, care creams, anti-acne preparations, local analgesics, make-up formulations of mascara, foundation or nail varnish type, products intended to be applied to the lips or other mucous membranes, sticks, solid compositions of toilet soap type and other formulations of the same type.

Conventionally, these various formulations incorporate, in addition to one or more active principles specific to the targeted application, a certain number of so-called more conventional compounds which have in particular the role of conferring on them either a prolonged stability over time (preserving agent, for example) and/or a specific pharmaceutical formulation form (of gel, cream, milk or lotion type, for example). They are generally surfactants and/or dispersing, stabilizing, emulsifying, moisturizing, gelling or thickening agents.

Mention may in particular be made, by way of representation of conventional stabilizing and/or thickening agents, of crosslinked polyacrylates, hydrocolloids obtained by fermentation, such as the gum Xanthane-Rhodicare® and a succinoglycan, such as Rh6ozan®, cellulose derivatives, such as hydroxypropylcellulose or carboxymethylcellulose, or -3guars and their derivatives, which are used alone or in combination.

It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

Accordingly the invention relates to an agent based on essentially amorphous cellulose nanofibrils having a degree of crystallinity of less than or equal to 50% which are provided in a dry form dispersible in an aqueous medium.

In a first aspect, the present invention provides use of essentially amorphous cellulose nanofibrils having a degree of crystallinity of less than or equal to 50% in a dry dispersible form which are combined with at least one S10 polyhydroxylated (polyOH) organic compound, as texturizing and/or strengthening agent in cosmetic formulations.

Native cellulose is generally always provided in a fibrillar form.

These fibrils are well known materials which have in particular already been proposed for modifying the texture of the media into which they are introduced. In the case of fluid media, they modify their viscosities, indeed even their rheological profiles.

Nanofibrils can be of various origins, for example of plant, bacterial, fungal or amoebic origin or the like.

There generally exists, in plant fibres or walls, a strong association between the nanofibrils. Secondary walls, resulting mainly from wood, and primary walls, a typical example of which is the parenchyma, can be distinguished among the walls. Parenchyma examples are composed of sugar beet pulp, citruses (lemons, oranges, grapefruit) and most fruits and vegetables. In the secondary walls, these fibrils are arranged in the form of highly oriented sheets, thus forming an indissociable fibre. They conventionally exist in the form of aggregates of a few tens of nanometres to a few micrometres. These aggregates are composed of individual fibrils which cannot be disentangled during their homogenization without being broken.

In the context of the present invention, the cellulose fibrils considered are essentially amorphous cellulose nanofibrils (CNF) preferably resulting from cells with primary walls.

The cellulose nanofibrils of the invention advantageously result from cells composed of at least approximately 80% of primary walls and preferably of at least 85% by weight.

The essentially amorphous cellulose nanofibrils used according to the invention thus preferably exhibit at least 80% of cells with primary walls.

In contrast to the cellulose fibrils from secondary walls discussed hereinabove, the cellulose nanofibrils exhibit a diameter of at most a few nanometres and have the appearance of filaments which it proves possible to disentangle during the homogenization stages.

They preferably exhibit a cross-section of between approximately 2 and approximately 10 nm. The latter is more preferably between approximately 2 and approximately 4 nm.

In the context of the invention, the nanofibrils under consideration are so-called essentially amorphous nanofibrils, in contrast to the so-called crystalline fibrils.

The term "essentially amorphous" is understood to define nanofibrils with a degree of crystallinity of less than or equal to 50%. According to a specific alternative form of the present invention, this degree of crystallinity is between and 50% and more preferably less than These essentially amorphous cellulose nanofibrils are particularly advantageous with regard to the crystalline microfibrils in the sense that they are dispersible in aqueous media, confer highly specific rheological properties of shear-thinning type and are stable, whether thermally or in media with high ionic charges. This high effectiveness displayed, at a reduced amount, by the cellulose nanofibrils is in fact a consequence of their excellent rheological behaviour in terms of yield point and of shear-thinning ability.

According to a preferred form of the invention, the cellulose nanofibrils used according to 6 the invention are surface-charged with carboxylic acids or with acidic polysaccharides, alone or as a mixture.

The term "carboxylic acids" is understood to mean simple carboxylic acids and their salts. These acids are preferably chosen from uronic acids and are more particularly galacturonic acid and/or glucuronic acid.

Mention may be made, as acidic polysaccharides, of pectins, including more particularly polygalacturonic acids. These acidic polysaccharides can be present as a mixture with hemicelluloses.

In fact, these surface-charged nanofibrils do not result from a simple mixing between the said nanofibrils and the acids and polysaccharides. It concerns instead a close combination between these two types of compounds deriving directly from the process used to prepare the nanofibrils. This is because this preparation process can be such that the acids and polysaccharides are not completely separated from the fibres but remain at the surface of the latter, thus conferring highly specific properties on them. It is important to emphasize that these same properties will not be reproduced if, in succession, the nanofibrils are separated completely from these acids and/or polysaccharides and then the latter are re-added to the nanofibrils thus obtained.

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

Consequently, a subject-matter of the present invention is the use of essentially amorphous cellulose nanofibrils having a degree of crystallinity of less than or equal to 50% in a dry dispersible form which are combined with at least one polyhydroxylated (polyOH) organic compound, as texturizing and/or strengthening agent in cosmetic formulations.

Within the meaning of the present invention, a texturizing agent is an agent having a stabilizing and thickening role in the cosmetic composition incorporating it.

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

In addition, it has been observed that the combinations according to the invention can optionally be used as an emulsifying and stabilizing agent even in an aqueous medium comprising surfactants.

The use of cellulose nanofibrils combined with at least one (polyOH) in the dry form is not only economically advantageous both with regard to storage and transportation, for example, but also from the technical viewpoint because, with the dry redispersible form, aqueous suspensions can be prepared with a high content of dry active material.

The use of cellulose nanofibrils in this dry redispersible form as texturizing and/or strengthening agent in cosmetic compositions has unexpectedly proved to be advantageous in several respects.

For example, in the specific case of cosmetic formulations intended for skin use of cream type, for example, a significant improvement in the level of the skin penetration of the said formulations is noticed.

No "soaping" phenomenon is observed at the surface of the skin during the application of these formulations.

Finally, the cellulose nanofibrils according to the invention confer a very soft skin feel and an effect of tightening and protecting the skin surface, as well as a moisturizing effect.

As regards the specific case of hair formulations, the incorporation of cellulose nanofibrils combined with at least one polyhydroxylated organic compound strengthens the styling effect.

The use of the said combination with a dissolved water-soluble film-forming polymer or a dispersed water-insoluble film-forming polymer results in the production of a film-forming material exhibiting ~2!2~o good adhesion to a keratinous substrate with a cosmetic feel which is neither greasy nor sticky.

The water-soluble film-forming polymers used in accordance with the present invention can be: either a synthetic water-soluble film-forming polymer with a low glass transition temperature Tg, preferably of less than or equal to 20 0

C;

or a water-soluble film-forming polymer of natural origin (polysaccharide derived from cellulose) with a high Tg generally of greater than or equal to 400C.

Mention may be made, for example, of poly(vinyl alcohol), hydroxyethylcellulose, cellulose ethers generally used in cosmetics, guar gums or locust bean gums.

Likewise, in contrast to conventional thickening agents, the cellulose nanofibrils according to the invention do not affect the cosmetic properties of the formulations incorporating them. Advantageously, no curbing effect or loss in sheen/lustre is noticed and no decrease in the resistance to water is observed for the compositions.

Furthermore, a fragrance-strengthening effect has been demonstrated.

As mentioned above, the combining with the cellulose nanofibrils of at least one (polyOH), carried out during the process for the preparation of the cellulose nanofibrils, has the advantage of allowing V71 _Ua r" r them to be formulated in a dry dispersible form. This, of course, is of potential advantage for the preparation of the corresponding cosmetic formulations, in particular in offering greater flexibility of formulation due to the high content of active principle.

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

Mention may very particularly be made, by way of representation of these carbohydrates, of C-3 to C-6 and preferably C-5 or C-6 cyclic or linear monosaccharides, 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 sucrose esters, alcohol carbohydrates, for example sorbitol and mannitol, acid carbohydrates, for example gluconic, uronic and galacturonic acids and their salts, and ether carbohydrates, for example cellulose methyl-, ethyl-, carboxymethyl-, hydroxyethyl- and hydroxypropylethers.

As regards the polyalcohols, they can in particular be glycerol, pentaerythrol, propylene glycol, ethylene glycol and/or poly(vinyl alcohol)s.

In the specific case of carbohydrates and their derivatives, used together with essentially amorphous cellulose nanofibrils, mention may more particularly be made of carboxylated celluloses and preferably carboxymethylated cellulose, also denoted by

CMC.

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

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

For an identical mass, it moreover proves to be possible to further reduce the proportion thereof k N with respect to the nanofibrils by favouring the choice of a carboxymethylated cellulose with a high degree of substitution.

Such cellulose nanofibrils and carboxylated cellulose mixtures are disclosed in particular in Applications PCT/FR 97 01291, published under the number WO 98/02487, and PCT/FR 97 01290, published under the number WO 98/02486.

This polyhydroxylated (polyOH) organic compound is preferably chosen from carboxymethylcellulose, xanthan gum, guar, sorbitol, sucrose and their mixtures.

The cosmetic formulations obtained according to the invention preferably comprise the polyhydroxylated compound or compounds and the cellulose nanofibrils in a (polyOH) x100/[(polyOH) (CNF)] ratio by weight of greater than or equal to and less than or equal to 50% and preferably greater than or equal to 5% and less than or equal to According to a favoured form of the invention, they comprise cellulose nanofibrils in a form combined with carboxymethylcellulose (CMC) with a high degree of substitution in a (CMC) x 100/[(CMC) (CNF)] ratio by weight of greater than or equal to and less than or equal to It is also possible to combine, with the CMC, another polyhydroxylated derivative, such as sucrose, propylene glycol or poly(ethylene glycol), for example.

In this specific case, the (CMC) x 100/[(polyOH)total (CNF)] ratio by weight is then significantly lowered.

As regards the amounts of cellulose nanofibrils and (polyOH) which can be used according to the invention, it is clear that they depend on the type of the pharmaceutical formulation form targeted and/or on the effect desired in the cosmetic formulation, for example strengthening a moisturizing effect or alternatively contributing a protective effect on the epidermis, as in depilatory formulations.

Thus it is that larger amounts of texturizing agent according to the invention will be present in pharmaceutical formulation forms of cream type in comparison with those employed in formulations of fluid type.

The amount of mixture of cellulose nanofibrils and of polyOH(s) is preferably adjusted so that the said nanofibrils are present in a proportion of approximately 0.1 to 20% and more preferably of approximately 0.15 and 5% by weight of the cosmetic formulation.

By way of illustration, a concentration of cellulose nanofibrils and (polyOH) varying between 0.11 and 40% can be proposed for the preparation of formulations of cream type and a concentration of between 0.11 and 10% can be proposed for the [lacuna] formulations of fluid type. The values are proposed for a (polyOH) x 100/[(polyOH) (CNF)] ratio by weight of greater than or equal to 5% and less than or equal to The solid redispersible composition of cellulose nanofibrils employed according to the invention can comprise, in addition to the polyhydroxylated organic compound(s) defined hereinabove, at least one co-additive chosen from: compounds of formula (R 1

R

2 N)COA, in which R or R 2 which are identical or different, represent hydrogen or a C-l to preferably C-l to C-5, alkyl radical and A represents hydrogen, a C-l to preferably C-l to C-5, alkyl radical or the group R''R' 2 N, with R' 1 or R' 2 which are identical or different, representing hydrogen or a C-l to C-10, preferably C-l to alkyl radical; and anionic, nonionic or amphoteric surfactants, it being possible for these coadditives to be used alone or as a mixture.

Mention may in particular be made, by way of representation of these surfactants, of those identified hereinbelow in the text.

It should be noted that the use of these coadditives makes it possible, in combination with the if P jl' C-4 (polyOH), such as, for example, carboxymethylcellulose, to strengthen the shear-thinning profile of the cellulose nanofibrils after redispersion.

As regards the compounds of (R 1

R

2 N)COA type, use is preferably made of compounds comprising two amide functional groups. Preferably, urea is used as co-additive.

According to a specific 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 employed according to the invention are combined with one or more polyhydroxylated compounds and with one or more co-additive(s) mentioned above, 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 with respect to the weight of nanofibrils, polyhydroxylated compound(s) and coadditive(s).

The nanofibrils used according to the invention can be obtained from various processes already disclosed in the literature.

/<1 In particular, reference may be made to the process disclosed in European Patent Application EP-A-726,356.

The treatment is carried out therein on pulp from plants with primary walls, namely dehydrated wet pulp, preserved by ensilage or partially depectinated, such as, for example, beet pulp, after the latter has been subject to a preliminary stage of extraction of the sucrose, according to methods known in the art.

More specifically, this treatment employs a first acidic or basic extraction, on conclusion 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, the washing and then the bleaching of the two combined residues formed of cellulose material, the dilution of the third solid residue obtained on conclusion of the bleaching stage, then the dilution of the resulting suspension, so as to obtain a level of dry matter of between 2 and 10% by weight, and, finally, a homogenization stage comprising at least one cycle of the diluted suspension.

This homogenization stage corresponds to any mixing, milling operation or any high mechanical shearing operation, followed by one or more passes of the cell suspension through an orifice with a small diameter, subjecting the suspension to a fall in y l pressure of at least 20 mPa and to a high-speed shearing action, followed by a high-speed deceleration impact. The homogenization of the cellulose suspension is obtained by a number of passes which can vary between 1 and 20, preferably between 2 and 5, until a stable suspension is obtained.

As regards the detailed protocol of each of the stages of this treatment, reference will be made to the description of the application identified hereinabove.

The process which has just been described makes it possible to obtain nanofibrils which retain carboxylic acids and/or polysaccharides at their surface.

In the case of the cellulose nanofibrils used according to the invention, a polyhydroxylated compound of, for example, carboxylated cellulose type is introduced into the preparation protocol described hereinabove, either before carrying out the homogenization stage or after a homogenization cycle has been carried out.

It should be noted that this alternative process form is disclosed in International Patent Application No. PCT/FR 97/01291, published under the number WO 98/02487, to which reference may be made, if necessary.

i The process for the preparation of the cellulose nanofibrils additivated with polyhydroxylated compound(s) consists, in a first stage, in adding to the suspension of nanofibrils, which has optionally been subjected to at least one homogenization cycle, at least a portion of the polyhydroxylated compound under consideration and optionally of the co-additive or coadditives. Then, in a second stage, a stage of drying the thus additivated suspension is carried out.

In fact, the addition of at least a portion of the polyhydroxylated compound and optionally of the co-additive or co-additives can be carried out according to three alternative forms: either, and preferably, [lacuna] on conclusion of the homogenization stage, after the latter has been subjected to at least one concentration stage, or to the suspension on conclusion of the homogenization stage, before the latter has been subjected to at least one concentration stage, or before or during the homogenization stage, the pulp then having been subjected to at least one cycle of the homogenization stage.

The concentration stage or stages can be carried out by any conventional means until a dry extract of approximately 35% by weight is obtained.

:6 /r More particularly, the dry extract is between 5 and by weight.

Prior to the drying stage proper, it may be advantageous to shape, namely by extrusion or granulation, the suspension which has been concentrated. The temperature of the drying stage is, of course, selected so as to limit any decomposition of the carboxylic acids, acidic polysaccharides, hemicelluloses, polyhydroxylated compounds and, if appropriate, co-additives. It is more particularly between 30 and 80 0 C, preferably between 30 and 600C.

The drying stage, carried out by conventional means, is carried out so as to maintain a minimum of 3% by weight of water with respect to the weight of the solid manufactured. More particularly, the weight of water maintained is between 10 and 30% by weight. Such an implementation does not allow the threshold to be exceeded beyond which the redispersion of the nanofibrils may no longer be complete.

The suspension of cellulose nanofibrils which is obtained by redispersion in water of the mixture obtained according to the protocol described above advantageously exhibits a viscosity level corresponding to at least 50%, for a shear rate of at least 1 s 1, of the viscosity level of a suspension of cellulose nanofibrils which has not been subjected to a drying 6 /1 c stage and which comprises neither polyhydroxylated compound nor co-additives.

Of course, the essentially amorphous surfacecharged cellulose nanofibrils, preferably charged with acid, combined with a polyhydroxylated compound and optionally with a co-additive are employed in the cosmetic formulations obtained according to the invention as a mixture with at least one vehicle which is compatible with a hair, skin or antisun application.

The term "compatible" with an application on the hair and/or the skin means in this instance that this vehicle does not damage or exert a negative effect on the appearance of the hair and/or the skin or does not cause irritation to the skin and/or to the eye and/or to the scalp.

Another subject-matter of the present invention is cosmetic formulations employing, as texturizing and/or strengthening agent, essentially amorphous cellulose nanofibrils in a dry dispersible form which are combined with at least one polyhydroxylated organic compound as defined above.

These formulations can also comprise an additive as defined hereinabove.

The cosmetic formulations in accordance with the invention preferably require a vehicle, or a mixture of several vehicles, present in the said formulations at concentrations of between 0.5 and 99.5%

I-,

Ao approximately and more preferably between 5 and approximately.

The vehicles which are compatible with the formulations according to the invention comprise, for example, those used in sprays, foams, tonics, gels, shampoos or 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 of which it has been applied (for example, spray, foam, lotion, tonic or gel) will not be the appropriate vehicle for a formulation which has to be rinsed off after use (for example, conditioner, rinsing lotion) The vehicles which are capable of being used can therefore be simple or complex and can include a large number of products commonly used in cosmetic formulations intended for a hair, skin or antisun use.

It can thus be water, optionally supplemented by a solubilizer in order to dissolve or disperse the active principles used, such as C-I to C-6 alcohols, and their mixtures, in particular ethanol, isopropanol or propylene glycol and their mixtures.

Advantageously, good compatibility of the cellulose nanofibrils combined with at least one polyhydroxylated organic compound is recorded with regard to solubilizers of alcohol type. The texturizing

S

properties of these cellulose nanofibrils are not detrimentally affected in aqueous/alcoholic media.

Likewise, they retain their properties in socalled more aggressive media, i.e. very acidic media, such as creams with a-hydroxy acids, or alkaline media, such as depilatory formulations or perming lotions.

Examples 2 and 3 presented hereinbelow describe this advantageous behaviour of the cellulose nanofibrils combined with at least one polyOH in a cosmetic application.

The CNFs formulated according to the invention advantageously prove to be excellent structuring agents for cosmetic media and retain their properties over time. Their viscosifying power is greater than that of microcrystalline celluloses.

It is also possible to combine, in a fatty phase separate from the aqueous phase of the CNFs according to the invention, one or more emollients chosen from: mineral oils (such as Marcol 82 vegetable oils or oils of marine origin, halogenated hydrocarbons, linalol, 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 provided in the form of sprays, tonic lotions, gels or foams, \w c r G the preferred solvents comprise water, ethanol, volatile silicone derivatives, and their mixtures. The solvents used in these mixtures can be miscible or immiscible with one another. The aerosol sprays and foams can also use any propellant capable of generating the products in the form of uniform fine sprays or foam. Mention may be made, by way of examples, of dimethyl ether, propane, n-butane or isobutane.

In the case where the cosmetic formulations are intended for a topical local application, the vehicles must have good pleasing properties, be compatible with all the other components and be completely harmless.

These vehicles can take a great many forms, of emulsion, foams or sprays type, and the like. For example, the vehicles in the form of emulsions include water-in-silicone, water-in-oil, oil-in-water and oilin-water-in-silicone emulsions. These emulsions cover a wide viscosity range, for example from 100 to 20,000 mPa-s at 25 0 C. These emulsions can also be delivered in the form of sprays by using either a device of mechanical pump type or a device pressurized by the use of a propellant gas.

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

At the same time as the vehicles identified above, the cosmetic formulations according to the -3ii invention can comprise surface-active agents employed to disperse, emulsify, dissolve or stabilize various compounds used in particular for their emollient or moisturizing properties. They can be of anionic, nonionic, cationic, zwitterionic or amphoteric type.

Mention may more particularly be made, by way of illustration of these compounds, of: anionic surface-active agents, such as alkyl ester sulphonates, alkyl sulphates, alkylamide sulphates and salts of saturated or unsaturated fatty acids; nonionic surface-active agents, such as polyoxyalkylenated alkylphenols, glucosamides, glucamides or glycerolamides derived from N-alkylamines, polyoxyalkylenated C-8 to C-22 aliphatic alcohols, products resulting from the condensation of ethylene oxide with a hydrophobic compound or resulting from the condensation of propylene oxide with propylene glycol, amine oxides, alkyl polyglycosides and their polyoxyalkylenated derivatives, C-8 to C-20 fatty amides and ethoxylated fatty acids, amides, amines or amidoamines; amphoteric and zwitterionic surface-active agents, such as those of betaine type, such as betaines, sulphobetaines, amidoalkyl betaines and amidoalkyl sulphobetaines, alkyl sultaines, the condensation products of fatty acids and of protein hydroxylates, cocoamphoacetates and cocoamphodiacetates, alkyl amphopropionates or alkyl amphodipropionates, or amphoteric derivatives of alkylpolyamines.

Conditioners can also be present.

Mention may be made, among these, of those of synthetic origin better known under the name polyquaternium, such as polyquaternium-2, polyquaternium-7 and polyquaternium-10, cationic derivatives of polysaccharides, such as cocodimonium hydroxyethyl cellulose, guar hydroxypropyl trimonium chloride or hydroxypropyl guar hydroxypropyl trimonium chloride, or non-volatile silicone derivatives, such as amodimethicone, cyclomethicones or organopolysiloxanes which are water-insoluble and non-volatile, such as oils, resins or gums, for example diphenyl dimethicone gums.

The cosmetic formulations can also comprise polymers exhibiting film-forming properties which can be used to contribute a fixing role. These polymers are generally present at concentrations of between 0.01 and preferably between 0.5 and They are preferably of the following types: polyvinylpyrrolidone, copolymers of polyvinylpyrrolidone and of methyl methacrylate, copolymer of polyvinylpyrrolidone and of vinyl acetate, poly(ethylene glycol erephthale)/poly(ethylene glycol) copolymers or sulphonated terephthalic copolyester polymers.

The cosmetic formulations can also comprise polymeric derivatives exercising a protective role, in amounts of the order of 0.01 to 10%, preferably approximately 0.1 to by weight, derivatives such as cellulose derivatives, poly(vinyl ester)s grafted onto polyalkylene backbones, poly(vinyl alcohol)s, sulphonated terephthalic copolyester polymers, ethoxylated monoamines or polyamines, and ethoxylated amine polymers.

Moisturizing agents can also be incorporated in the cosmetic formulations. Mention may in particular be made, by way of illustration of these agents, of glycerol, propylene glycol, urea, collagen, gelatin and emollients which are generally chosen from alkyl monoglycerides, alkyl diglycerides or triglycerides, such as oils extracted from plants and vegetables or their hydrogenated derivatives, mineral oils or paraffin oils, diols, fatty esters or silicones.

One or more fragrances, colouring agents and/or opacifying agents, such as pigments, is/are generally added to these compounds.

K V To protect the skin and/or the hair from attack by the sun and UV radiation, sunscreens can be added to these formulations, which sunscreens are either organic compounds which strongly absorb UV radiation or inorganic particles in the nanoparticulate state, such as zinc oxide, titanium dioxide or cerium oxides.

Active principles, such as vitamins, ahydroxy acids, plant derivatives or marine extracts, with purely cosmetic properties, can be incorporated in the formulations comprising CNFs for the purpose of a treating effect.

Likewise, the CNFs are preferred texturizing agents of depilatory formulations, such as the media based on calcium thioglycolate, for example.

Preserving agents, such as p-hydroxybenzoic acid esters, sodium benzoate or any chemical agent which prevents bacterial or mould proliferation and which is used conventionally in cosmetic compositions, are generally introduced into these compositions at a level of 0.01 to 3% by weight in accordance with Appendix VII of the Cosmetics Regulations.

Finally, the cosmetic formulations can also comprise viscosifying or gelling polymers, such as crosslinked polyacrylates of Carbopol® type sold by Goodrich, cellulose derivatives, such as hydroxypropylcellulose or carboxymethylcellulose, guars and their I L

I

derivatives, such as hydroxypropyl guar, for example Jaguar HP®, locust bean [lacuna], tara or cassia gum, xanthan gum, such as Rhodicare®, succinoglycans, alginates, carrageenans, chitin derivatives or any other polysaccharide with a texturizing role.

It is clear that the choice of these socalled conventional compounds and the assessment of their respective amounts are directly related to the type of formulation envisaged, namely gel, cream, milk, spray, lotion, and the like, and to the desired pleasing nature. These adjustments are in fact a matter of routine operations for the cosmetic formulator.

The cosmetic formulations according to the invention can advantageously be employed in the hair, antisun, bodycare and make-up fields.

The examples submitted hereinbelow are presented simply by way of illustration and without implied limitation of the present invention.

EXAMPLE 1 Preparation of a mixture of cellulose nanofibrils and of carboxymethylcellulose A carboxymethylcellulose with a degree of substitution of 1.2 (CMC Blanose® 12M8P from Aqualon) is dissolved in distilled water.

The solution is subsequently added to the nanofibril mother dispersion comprising 2.3% of cellulose nanofibrils which has been prehomogenized with an Ultra-Turrax at 14,000 rev/min (1 min per 100 g of dispersion). The combined mixture is stirred with a deflocculating paddle at 1000 rev/min for 30 min.

The amount of carboxymethylcellulose added is by weight with respect to the weight of cellulose nanofibrils and of carboxymethylcellulose.

The mixture is subsequently poured into dishes and then dried, i.e. in a ventilated oven at 40 0 C, to a solids content of 92%, monitored by quantitative water determination by the Karl-Fischer method.

The dried mixture is subsequently milled and then sieved through a 500 pm sieve.

The powder obtained is redispersed in a proportion of 0.43% by weight of cellulose nanofibrils and of carboxymethylcellulose in distilled water.

Stirring is carried out with a deflocculating paddle at 1000 rev/min for 5 min or 30 min. This dispersion is employed in the examples hereinbelow.

EXAMPLE 2 Behaviour of CNF combined with CMC in alcoholic medium To do this, the CNF/CMC mixture prepared in Example 1 is dispersed in water with shearing and then the alcohol under consideration is or is not added.

The compositions of the two aqueous/alcoholic media thus prepared are described in Table I presented hereinbelow. The viscosities of these media and of a control medium (water) are evaluated using a viscometer of Brookfield LVT type.

The results appear in Table I.

TABLE I Additivated CNF 85/15 CMC 0.43% Viscosity, Pa-s 10% Ethanol 10% Propylene Distilled glycol water 1 s' 1 0.8 0.85 0.60 100 s 0.04 0.04 0.035 EXAMPLE 3 Behaviour of CNF combined with CMC in acidic or alkaline medium The CNF mixture prepared according to Example 1 is introduced into water buffered at a pH of 4 or of 9. The rheological behaviour of this medium is assessed with regard to a control medium comprising 1% of microcrystalline celluloses additivated with CMC. The change in the viscosity over time is described in Table

II.

TABLE II Texturizing Viscosity, Pa*s Agent 1 s 1 100 s 1 d pH=4 pH=9 pH=4 PH=9 0.43% of additivated id 0.35 0.55 0.015 0.02 CNF 85/15 CMC 5d 0.35 0.65 0.015 0.02 1% of microcrystalline Id 0.02 0.03 celluloses additivated 5d 0.02 0.03 [lacuna] CMC It is noted that the CNFs formulated according to the invention prove to be excellent structuring agents for cosmetic media and retain their properties over time. Their viscosifying power is greater than that of microcrystalline celluloses.

EXAMPLE 4 Cosmetic formulations according to the invention These formulations comprise the CNF/CMC mixture prepared in Example 1.

A7 1) Cream with a-hydroxy acids Ingredients Phase A o Cetearyl. alcohol E3 Diethylamine cetyl phosphate o Icosene/PVP copolymer Octyldodecyl neopentanoate o Mirasil 0DM 300: Dimethicone Phase B o CNF /CMC Propylene glycol o Water Phase C u a-Hydroxy acids Phase D u Triethanolamine Phase E O Preservative %by weight 8 2 2 1 0.2 q.s. 100 1.8 q.s.

~jI, ~1-

V

2) Gentle exfoliant for the body Ingredients Phase A o Water Phase B L CNF/CMC Phase C o Magnesium lauryl sulphate o Sodium cocoyl sarcosinate 55% Sodium hydroxide o Diethylamine lauramide o Stearic acid o Geropon AC78®: sodium cocoyl isethionate Phase D o Poly(ethylene oxide) Phase E o Preservative o Fragrance and dye by weight q.s. 100 1 0.50 13 q.s.

q.s.

'I

3) Depilatory lotion Ingredients Phase A o CNF/CMC u Water Phase B o Propylene glycol Phase C o Mineral oil and lanolin alcohol o Polysorbate 80 and cetyl acetate and acetylated lanolin alcohol o PEG-100 stearate and glyceryl stearate Phase D o Calcium thioglycolate o Calcium hydroxide Phase E o Preservative, dye, fragrance by weight q.s. 100 2 2 6 q.s. 100 EXAMPLE Behaviour of CNF combined with CMC as strengthening agent for a dispersion of film-forming polymer The aim of this example is to show that the combination of nanofibrils with at least one (polyOH) can also be a strengthening agent.

The tests were carried out with a Rhodopas DS 1003 film-forming latex sold by Rhodia (aqueous dispersion of acrylic polymer), for which the glass transition temperature Tg is 12 0 C, the film formation temperature TMF [lacuna] less than 50C, the solids content of the dispersion is 50% and the particle size of the said latex is 0.1 gm. The dispersion exhibits a pH equal to approximately 8.

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

Formulation which can act as aqueous nail varnish base Two formulations based on DS 1003 latex as defined hereinabove are prepared: F1 (comparative): 30% of 1003 latex 70% by weight of water, with respect to the total weight of the formulation; F2 (according to the invention): 30% by weight of 1003 latex 1% by weight of CNF obtained in Example 1 69% by weight of water, with respect to the total weight of the formulation.

The pH of the medium is adjusted to 7.

F1 exhibits a viscosity of less than mPa-s, whereas the viscosity of F2 is approximately 4500 mPa-s. The viscosities are evaluated using a viscometer of Brookfield LVT type (rotor 3, revolutions/minute) The results are summed up in Table III.

7 i Table III F1 F2 Film-forming aspect Non-film-forming Translucent film Persoz hardness 49 (in s) Adhesion 0 0 (no detachment) The Persoz hardness is determined according to NFT Standard 30-016: the hardnesses are measured at 3 different points on the plate after drying for more than 8 days at room temperature. Each measurement corresponds to the mean of 3 measurements. The results show the time (in seconds) which the pendulum takes to dampen its oscillation from an angle of 120 to an angle of The time increases as the film increases in "hardness".

The adhesion to the substrate is determined by a cross-hatching test according to ISO Standard 2409: the films were prepared on steel plates. The test consists in cross-hatching the film with 2 series of 6 perpendicular lines 1 mm apart using a cutter and in tearing off this cross-hatching with an adhesive tape.

The grading ranges from 0 (no detachment) to 4 (detachment of approximately 50% of the crosshatching).

The formulation F2, which comprises the additivated CNFs of the invention, thus corresponds to a material which might be used as aqueous varnish base.

The formulation F2 obtained is stable. With a pseudoplastic nature, it spreads easily over the substrates. The film exhibits good adhesion and good flexibility with a feel which is neither greasy nor sticky.

uS""7~~ i.

Claims (19)

1. Use of essentially amorphous cellulose nanofibrils having a degree of crystallinity of less than or equal to 50% in a dry dispersible form which are combined with at least one polyhydroxylated (polyOH) organic compound, as texturizing and/or strengthening agent in cosmetic formulations.

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

3. Use according to claim 2, wherein the carbohydrates are 0 chosen from C-3 to C-6 cyclic or linear monosaccharides, oligosaccharides, polysaccharides and their fatty derivatives, such as fatty acid sucrose esters, and alcohol, acid and ether carbohydrates. o

4. Use according to any one of claims 1 to 3, wherein the 0. polyhydroxylated (polyOH) organic compound is chosen from carboxymethylcellulose, xanthan gum, guar, sorbitol, sucrose and their mixtures.

Use according to any one of claims 1 to 4, wherein the degree of crystallinity is between 15 and

6. Use according to claim 5, wherein the degree of crystallinity is less than

7. Use according to any one of claims 1 to 6, wherein the cellulose nanofibrils exhibit at least 80% of cells with primary walls.

8. Use according to any one of claims 1 to 7, wherein the cellulose nanofibrils result from cells. -39-

9. Use according to claim 8, wherein the cells are composed of at least approximately 80% of primary walls.

Use according to any one of claims 1 to 9, wherein the cellulose nanofibrils are charged with carboxylic acids and with acidic polysaccharides, alone or as a mixture.

11. Use according to any one of claims 1 to 10, wherein the polyhydroxylated organic compound is combined with the cellulose nanofibrils in a (polyOH) x 100 [(polyOH) (CNF)] ratio by weight of greater than or equal to 5% and less than or equal to

12. Use according to claims 11, wherein the (polyOH) x 100 [(polyOH) (CNF)] ratio by weight is greater than or equal to 5% and less than or equal to

13. Use according to any one of claims 4 to 12, wherein the cellulose nanofibrils are combined therein with carboxymethylcellulose (CMC) with a high degree of substitution in a (CMC) x 100 [(CMC) (CNF)] ratio by weight of greater than or equal to 5% and less than or equal to

14. Use according to any one of the preceding claims, wherein the amount of mixture of cellulose nanofibrils and of (polyOH) is adjusted so that the said nanofibrils are used in a proportion of 0.1 to 20% by weight of the cosmetic formulation.

Use according to claim 14, wherein the nanofibrils are used in a proportion of 0.15 to 5% by weight. *Y

16. Use according to any one of the preceding claims, wherein the cellulose nanofibrils and the (polyOH) are combined with at least one co- additive chosen from: compounds of formula (R1RN)COA, in which R 1 or R 2 which are identical or different, represent hydrogen or a C-l to C-10, alkyl radical and A represents hydrogen, a C-1 to C-10, alkyl radical or the group *o 2 1 2 R'R' 2 N with or R' 2 which are identical or different, representing hydrogen or a C-1 to C-10, alkyl radical; 10 and anionic, nonionic or amphoteric surfactants, it being possible for these co-additives to be used alone or as a mixture. go

17. Use according to claim 16, wherein R 2 A, R' or R' 2 represent a C-1 to C-5 alkyl radical.

18. Use according to claim 16 or claim 17, wherein the content of polyhydroxylated compound(s) and of co-additive(s) is greater than or equal to by weight and less than or equal to 30% by weight with respect to the weight of nanofibrils, polyhydroxylated compound(s) and of co-additive(s).

19. Use of essentially amorphous cellulose nanofibrils, substantially as herein described with reference to any one of the examples but excluding comparative examples. DATED this 26th Day of February 2002 RHODIA SERVICES 25 Attorney: DENIS E. TUFFERY Registered Patent Attorney Sj of BALDWIN SHELSTON WATERS !,6