The present invention relates to a cosmetic composition comprising at least one anionic surfactant, at least 3.5% by weight of at least one fatty acid in a particular anionic surfactant(s)/fatty acid(s) weight ratio, and at least one antidandruff agent, to its use for the cosmetic treatment of keratin fibres and to a cosmetic treatment process using this composition.

In the field of hair hygiene, dandruff problems affect up to 50% of the population worldwide. The appearance of dandruff is an inconvenience, in particular from an aesthetic viewpoint.

Care products exist which make it possible to limit these phenomena. However, these products are generally unstable and are not always sufficiently effective.

In particular, these products may have particle flocculation or sedimentation problems.

Specifically, most of the antidandruff agents used are hydrophobic fillers. The incorporation and the stability of these antidandruff agents may prove difficult for a person skilled in the art for two reasons: the placing of the antidandruff fillers in suspension, and the formation of aggregates which may reduce the specific surface area of the active agent and thus potentially its efficacy. The addition of suspensive polymers in high concentration is often necessary to stabilize the antidandruff active agents in the formulation, but this may have a negative impact on the foam abundance and the price of the formulations.

There is thus a need to develop compositions for the cosmetic treatment of keratin fibres that can overcome the drawbacks mentioned above, and that can achieve good stability and good working qualities such as easy and homogeneous distribution and good foam quality, and also very good cosmetic properties in terms of feel, smoothness, suppleness and disentangling.

The Applicant has now discovered that a combination of at least one anionic surfactant, at least 3.5% by weight, relative to the total weight of the composition, of at least one fatty acid, and of at least one antidandruff agent, the anionic

surfactant(s)/fatty acid(s) weight ratio being from 0.5 to 3.5, makes it possible to achieve the objectives outlined above.

This combination makes it possible to obtain surfactants arranged in lamellar structured phases. These structured phases have remarkable rheological characteristics that lead to the production of suspensive properties and a capacity for stabilizing hydrophobic fillers of antidandruff active agent type. Oil-mediated vectorization of fillers of this type has an additional advantage in terms of the dispersing and formulating of these active agents.

One subject of the invention is thus a cosmetic composition comprising:

(i) one or more anionic surfactants,

(ii) at least 3.5% by weight of one or more fatty acids, relative to the total weight of the composition, and

(iii) one or more antidandruff agents,

the anionic surfactant(s)/fatty acid(s) weight ratio being from 0.5 to 3.5.

This composition is in the form of structured phases that are stable, and makes it possible to obtain good foam volume. In addition, it leads to the production of excellent cosmetic properties, most particularly of the suppleness and smooth feel of the hair; it also makes it possible to improve the feel and the disentangling, especially on hair that has been sensitized, in particular by bleaching treatments.

A subject of the present invention is also a cosmetic treatment process, and more particularly a process for washing and conditioning keratin fibres, in particular human keratin fibres, such as the hair, comprising the use of the composition according to the invention.

Another subject of the invention consists of the use of a composition according to the invention for the cosmetic treatment of keratin fibres, in particular human keratin fibres, and more particularly the hair.

Other subjects, characteristics, aspects and advantages of the invention will emerge even more clearly on reading the description and the examples that follow.

The figure 1 describes the stability of two compositions with or without lauric acid.

The figure 2 describes the stability of two compositions according to the ratio between anionic surfactants/fatty acids.

In the text hereinbelow, unless otherwise indicated, the limits of a range of values are included in that range, especially in the expressions "between" and "ranging from ... to ...".

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

For the purposes of the present invention, the term "stable composition" more particularly means a composition which does not show any particle flocculation or sedimentation, or any phase separation or decantation, when it is stored at a given temperature, especially between 10 and 50°C for a period ranging from a few days to 2 months.

According to the invention, the cosmetic composition comprises:

(i) one or more anionic surfactants,

(ii) at least 3.5% by weight of one or more fatty acids, relative to the total weight of the composition, and

(iii) one or more antidandruff agents,

the anionic surfactant(s)/fatty acid(s) weight ratio being from 0.5 to 3.5.

The term "anionic surfactant" means a surfactant comprising, as ionic or ionizable groups, only anionic groups. These anionic groups are preferably chosen from the following groups: -C02H, -C02 , -S03H, -S03~, -OS03H, -OS03~, -H2P03, -HP03", -P032~, -H2P02, -HP02~, -P022~, -POH or -PO
As examples of anionic surfactants that may be used in the composition according to the invention, mention may be made of alkyl sulfates, alkyl ether sulfates, alkylamido ether sulfates, alkylaryl polyether sulfates, monoglyceride sulfates, alkylsulfonates, alkylamidesulfonates, alkylarylsulfonates, a-olefmsulfonates, paraffin sulfonates, alkyl sulfosuccinates, alkyl ether sulfosuccinates, alkylamide sulfosuccinates, alkyl sulfoacetates, acyl sarcosinates, acyl glutamates, alkyl sulfosuccinamates, acyl isethionates and N-acyltaurates, salts of alkyl monoesters of polyglycoside-polycarboxylic acids, acyl lactylates, D-galactoside-uronic acid salts, alkyl ether carboxylic acid salts, alkylaryl ether carboxylic acid salts, alkylamido ether carboxylic acid salts; and the corresponding non-salified forms of all these compounds; the alkyl and acyl groups of all these compounds comprising from 6 to 40 carbon atoms and preferably from 6 to 24 carbon atoms and the aryl group denoting a phenyl group.

These compounds may be oxyethylenated and then preferably comprise from 1 to 50 ethylene oxide units.

The salts of C6-C24 alkyl monoesters of polyglycoside-polycarboxylic acids may be chosen from C6-C24 alkyl polyglycoside-citrates, C6-C24 alkyl polyglycoside-tartrates and C6-C24 alkyl polyglycoside-sulfosuccinates.

When the anionic surfactant(s) are in the form of salts, they may be chosen from alkali metal salts such as the sodium or potassium salt and preferably the sodium salt, the ammonium salts, the amine salts and in particular the amino alcohol salts or the alkaline-earth metal salts such as the magnesium salt.

Examples of amino alcohol salts that may especially be mentioned include monoethanolamine, diethanolamine and triethanolamine salts, monoisopropanolamine, diisopropanolamine or triisopropanolamine salts, 2-amino-2-methyl-l-propanol salts, 2-amino-2-methyl-l,3-propanediol salts and tris(hydroxymethyl)aminomethane salts.

Alkali metal or alkaline-earth metal salts and in particular the sodium or magnesium salts are preferably used.

In a first variant, the anionic surfactants may be chosen from (C6-C24)alkyl sulfates, (C6-C24)alkyl ether sulfates comprising from 1 to 50 ethylene oxide units, especially in the form of alkali metal, ammonium, amino alcohol and alkaline-earth metal salts, or a mixture of these compounds.

Even better still, (Ci2-C2o)alkyl sulfates, (Ci2-C2o)alkyl ether sulfates comprising from 1 to 20 ethylene oxide units, in particular in the form of alkali metal, ammonium, amino alcohol and alkaline-earth metal salts, or a mixture of these compounds, are preferred in this variant. Better still, sodium or ammonium lauryl sulfate and sodium lauryl ether sulfate are preferred.

In a second variant, the anionic surfactants may be chosen from surfactants comprising anionic groups chosen from -C(0)OH, -C(0)0", -SO3H or -S(0)20", such as alkylsulfonates, olefin sulfonates, alkylamide sulfonates, alkyl sulfosuccinates, alkyl ether sulfosuccinates, alkylamide sulfo succinates, alkyl sulfoacetates, acyl sarcosinates, acyl glutamates, alkyl sulfosuccinamates, acyl isethionates, N-acyltaurates, acyl lactylates or N-acylglycinates, the alkyl and acyl groups of all these compounds comprising from 6 to 40 carbon atoms and preferably from 6 to 24 carbon atoms.

Most particularly, use may be made of (C6-4o acyl)glutamates, better still (C6- 24 acyl)glutamates, for instance the disodium cocoyl glutamate provided under the trade name Plantapon ACG LC by the company BASF, or (C6-4o acyl)isethionates and better still (C6-24 acyl)isethionates, for instance the sodium lauroyl methyl isethionate sold by the company Innospec under the trade name Iselux LQ-CLR-SB.

The anionic surfactant(s) are preferably present in a total amount ranging from 0.1% to 40% by weight, preferably ranging from 1% to 30%> by weight, better still from 10% to 20% by weight and preferentially from 11% to 15% by weight, relative to the total weight of the composition.

The cosmetic composition comprises one or more fatty acids as other essential ingredient.

For the purposes of the present invention, the term "fatty acid" means an acid comprising at least one linear or branched, saturated or unsaturated hydrocarbon-based chain, such as alkyl or alkenyl, comprising at least 8 carbon atoms, preferably from 8 to 30 carbon atoms, and better still from 10 to 22 carbon atoms.

They preferably have the structure R-COOH in which R denotes a linear or branched C7-C31 , preferably C9-C21 , better still C9-C17 alkyl or alkenyl group.

As examples of fatty acids that may be used in the present invention, mention may be made especially of lauric acid, oleic acid, linoleic acid, linolenic acid, undecylenic acid, isocetylic acid, isostearylic acid, cetylic acid, stearylic acid and cetylstearylic acid, and mixtures thereof.

Preferably, the fatty acid is chosen from linear fatty acids, better still from saturated linear C10-C22 and especially C10-C18 fatty acids.

Lauric acid may preferentially be used.

The fatty acid(s) are preferably present in a total amount ranging from 3.5% to 30%) by weight, preferably from 3.5% to 20% by weight, better still from 3.75% to 15% by weight and even better still from 4% to 8% by weight relative to the total weight of the composition.

Preferably, the composition has an anionic surfactant(s)/fatty acid(s) weight ratio ranging from 1 to 3 and more preferentially from 1.5 to 3.

According to the invention, the composition comprises one or more antidandruff agents.

The antidandruff agents that may be used according to the invention are especially chosen from the families (1) to (10) below:

1) pyridinethione salts, in particular the calcium, magnesium, barium, strontium, zinc, cadmium, tin and zirconium salts. The zinc salt of pyridinethione is particularly preferred.

The zinc salt of pyridinethione is sold in particular under the name Omadine zinc by the company Arch Personal Care;

2) l-hydroxy-2-pyrrolidone derivatives represented especially by formula

(i);

in which Kg represents an alkyl group containing from 1 to 17 carbon atoms, an alkenyl group containing from 2 to 17 carbon atoms, a cycloalkyl group containing from 5 to 8 carbon atoms, a bicycloalkyl group containing from 7 to 9 carbon atoms; a cycloalkylalkyl group, an aryl group, an aralkyl group with an alkyl containing from 1 to 4 carbon atoms, an arylalkenyl group with an alkenyl containing from 2 to 4 carbon atoms, aryloxyalkyl or arylmercaptoalkyl with an alkyl containing from 1 to 4 carbon atoms, a furylalkenyl group with an alkenyl or a furyl containing from 2 to 4 carbon atoms, an alkoxy group containing from 1 to 4 carbon atoms, a nitro group, a cyano group or a halogen atom.

Rio represents a hydrogen atom, a C1-C4 alkyl group, a C2-C4 alkenyl group, a halogen atom, a phenyl group or a benzyl group;

Y represents an organic base, an alkali metal or alkaline-earth metal ion or an ammonium ion.

Examples of compounds of formula (I) include l-hydroxy-4-methyl-2-pyridone, l-hydroxy-6-methyl-2-pyridone, l-hydroxy-4,6-dimethyl-2-pyridone, 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone, l-hydroxy-4-methyl-6-

cyclohexyl-2-pyridone, 1 -hydroxy-4-methyl-6-(methylcyclohexyl)-2-pyridone, 1 -hydroxy-4-methyl-6-(2-bicyclo[2,2, 1 ]heptyl)-2-pyridone, 1 -hydroxy-4-methyl-6-(4-methylphenyl)-2-pyridone, 1 -hydroxy-4-methyl-6- [ 1 -(4-nitrophenoxy)butyl] -2-pyridone, 1 -hydroxy-4-methyl-6-(4-cyanophenoxymethyl)-2-pyridone, 1 -hydroxy-4-methyl-6-(phenylsulfonylmethyl)-2-pyridone and l-hydroxy-4-methyl-6-(4-bromobenzyl)-2-pyridone.

The compounds of formula (I) may be used in the form of salts with organic or mineral bases.

Examples of organic bases are especially alkanolamines of low molecular weight such as ethanolamine, diethanolamine, N-ethylethanolamine, triethanolamine, diethylaminoethanol and 2-amino-2-methylpropanediol; non-volatile bases such as ethylenediamine, hexamethylenediamine, cyclohexylamine, benzylamine and N-methylpiperazine; quaternary ammonium hydroxides, such as trimethylbenzylammonium hydroxide; guanidine and derivatives thereof, and particularly alkyl derivatives thereof. Examples of mineral bases are especially salts of alkali metals, e.g. sodium or potassium; ammonium salts, salts of alkaline-earth metals, such as magnesium or calcium; salts of di-, tri- or tetravalent cationic metals, e.g. zinc, aluminium or zirconium.

Alkanolamines, ethylenediamine and mineral bases such as alkali metal salts are preferred.

A compound of formula (I) that is particularly preferred is the one for which:

R9 denotes the group

CHQ CHQ

I 3 I 3

CH^ C ~~ CH,r~ CH— CH^-

Rio denotes a methyl group, and

X+ denotes N+H3CH2CH2OH.

This compound is sold, for example, under the name Octopirox (1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone, monoethanolamine salt) by the company Hoechst;

3) 2,2'-dithiobis(pyridine N-oxide) of formula (II):

The compounds of formula (II) may be introduced into the compositions in the form of mineral salts. An example of a mineral salt is magnesium sulfate;

4) the trihalocarbamides especially of formula (III) below:

in which Z represents a halogen atom such as chlorine or a C1-C4 trihaloalkyl group such as CF3;

5) triclosan, represented by formula (IV):

6) azole compounds such as climbazole, ketoconazole, clotrimazole, econazole, isoconazole and miconazole;

7) antifungal polymers such as amphotericin B or nystatin;

8) selenium sulfides, in particular those of formula SxSes-x, x ranging from 1 to 7;

9) extracts of one or more non-photosynthetic, non-fruiting filamentous bacteria.

The bacterial extracts that may be used according to the invention will be chosen from non-photosynthetic, non-fruiting filamentous bacteria as defined

according to the classification in Bergey's Manual of Systemic Bacteriology, volume

3, section 23, 9th edition 1989.

Among the bacteria that may be used, mention will be made more particularly of bacteria belonging to the order Beggiatoales, and especially bacteria belonging to the genus Beggiotoa, for instance various strains of Beggiotoa alba.

According to the definition, B. alba corresponds to the former names Beggiotoa arachnoidea, B. gigantea, B. leptomiformis, B. minima and B. mirabilis of Bergey's manual, 8th edition. Mention may moreover be made of bacteria belonging to the genus Vitreoscilla, which is known to be close to and often difficult to distinguish from the genus Beggiatoa. The bacteria that have just been defined, and several of which have been described, generally have an aquatic habitat, and may be found in particular in spring water sources.

Among the bacteria that may be used, mention may be made, for example, of Vitreoscilla beggiatoides (ATCC 43181) and Beggiatoa alba (ATCC33555).

Preferentially, according to the invention, the use of the extract of

Vitreoscilla filiformis, in particular the strain ATCC 15551, metabolites thereof and fractions thereof, are claimed.

Moreover, it is known that culturing non-photosynthetic, non-fruiting filamentous bacteria is relatively difficult, as is the production of pure cultures. Use will preferentially be made of the culture described in patent application WO

94/02158.

The term "extract of non-photosynthetic, non-fruiting filamentous bacteria" means not only the culture supernatant but also the biomass obtained after culturing said bacteria, the envelopes or envelope fractions, or the extracts of the biomass obtained by treating this biomass.

To prepare the extract according to the invention, said bacteria can be cultured and then separated from the biomass obtained, for example by filtration, centrifugation, coagulation and/or lyophilization.

The extracts that may be used may in particular be prepared according to the process described in patent application WO-A-93/00741. Thus, after culturing, the bacteria are concentrated by centrifugation. The biomass obtained is autoclaved. This biomass may be lyophilized to constitute what is known as the lyophilized extract. Any lyophilization method known to those skilled in the art may be used to prepare this extract.

The supernatant fraction of this biomass may also be filtered in a sterile container to remove the particles in suspension.

The terms "envelopes" and "envelope fractions" refer herein to the bacterial wall and possibly the subjacent membranes;

10) other antidandruff agents are sulfur in its various forms, cadmium sulfide, allantoin, coal or wood tars and derivatives thereof, in particular cade oil, salicylic acid, undecylenic acid, fumaric acid, ellagic acid, ellagic acid tannins, and allylamines such as terbinafme.

Even more preferentially, the antidandruff agents that may be used in the invention are chosen from pyridinethione salts, l-hydroxy-2-pyrrolidone derivatives, 2,2'-dithiobis(pyridine N-oxide) and selenium sulfides, and mixtures thereof.

Pyridinethione zinc, ( 1 -hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone and salts thereof and selenium sulfides are particularly preferred.

The antidandruff agent(s) are present in the composition according to the invention in preferential proportions ranging from 0.01% to 20% by weight, more preferentially from 0.1% to 10% by weight and better still from 0.2% to 5% by weight, relative to the total weight of the composition.

The composition according to the invention may also comprise one or more amphoteric or zwitterionic surfactants.

They may especially be derivatives of optionally quaternized secondary or tertiary aliphatic amines containing at least one anionic group, such as, for example, a carboxylate, sulfonate, sulfate, phosphate or phosphonate group, and in which the aliphatic group or at least one of the aliphatic groups is a linear or branched chain comprising from 8 to 22 carbon atoms.

Mention may be made in particular of (C8-C2o)alkylbetaines, sulfobetaines,

(C8-C2o)alkylamido(Ci-C6)alkylbetaines such as cocamidopropylbetaine, and (C8-C2o)alkylamido(Ci-C6)alkylsulfobetaines.

Mention may also be made, among the derivatives of optionally quaternized secondary or tertiary aliphatic amines capable of being employed, of the products with respective structures (V) and (VI) below:

Ra-CONHCH2CH2- N+(Rb)(Rc)(CH2COO ) (V) in which:

Ra represents a C10-C30 alkyl or alkenyl group derived from an acid Ra-COOH preferably present in hydrolysed coconut oil, or a heptyl, nonyl or undecyl group,

Rb represents a β-hydroxyethyl group, and

Rc represents a carboxymethyl group;

Ra'-CONHCH2CH2-N(B)(B') (VI) in which:

B represents -CH2CH2OX*,

X* represents the group -CH2-COOH, CH2-COOZ', -CH2CH2-COOH or

-CH2CH2-COOZ', or a hydrogen atom,

B' represents -(CH2)Z-Y', with z = 1 or 2,

Y* represents -COOH, -COOZ', or the group -CH2-CHOH-S03H or -CH2-CHOH-S03Z',

Z' represents an ion derived from an alkali or alkaline-earth metal, such as sodium, potassium or magnesium; an ammonium ion; or an ion derived from an organic amine and in particular from an amino alcohol, such as monoethanolamine, diethanolamine and triethanolamine, monoisopropanolamine, diisopropanolamine or triisopropanolamine, 2-amino-2-methyl- 1 -propanol, 2-amino-2-methyl- 1,3-propanediol and tris(hydroxymethyl)amino methane,

Ra' represents a Cio-C3o alkyl or alkenyl group of an acid Ra-COOH preferably present in coconut oil or in hydrolysed linseed oil, an alkyl group, in particular of C17 and its iso form, or an unsaturated C17 group.

These compounds are also classified in the CTFA dictionary, 5th edition, 1993, under the names disodium cocoamphodiacetate, disodium lauroamphodiacetate, disodium caprylamphodiacetate, disodium capryloamphodiacetate, disodium cocoamphodipropionate, disodium lauroamphodipropionate, disodium caprylamphodipropionate, disodium capryloamphodipropionate, lauroamphodipropionic acid and cocoamphodipropionic acid.

By way of example, mention may be made of the cocoamphodiacetate sold by the company Rhodia under the trade name Miranol® C2M Concentrate.

Use may also be made of compounds of formula (VIbis):

Ra"-NH-CH(Y")-(CH2)n-C(0)-NH-(CH2)n-N(Rd)(Re)

(VIbis) in which formula:

Y" represents the group -C(0)OH, -C(0)OZ", -CH2-CH(OH)-S03H or the group -CH2-CH(OH)-S03-Z";

Rd and Re, independently of each other, represent a C1-C4 alkyl or hydroxy alky 1 group;

Z" represents a cationic counterion derived from an alkali metal or alkaline-earth metal, such as sodium, an ammonium ion or an ion derived from an organic amine;

Ra" represents a Cio-C3o alkyl or alkenyl group of an acid Ra"-C(0)OH preferably present in coconut oil or in hydrolysed linseed oil;

n and n', independently of each other, denote an integer ranging from 1 to 3.

Among the compounds of formula (VIbis), mention may be made of the compound classified in the CTFA dictionary under the name sodium diethylaminopropyl cocoaspartamide and sold by the company Chimex under the name Chimexane HB.

Preferably, the amphoteric or zwitterionic surfactants are chosen from (C8-C2o)alkylbetaines, (C8-C2o)alkylamido(Ci-C6)alkylbetaines and (C8-C2o)alkyl amphodiacetates, and also mixtures thereof, and better still from (C8-C2o)alkylbetaines and (C8-C2o)alkylamido(Ci-C6)alkylbetaines.

When they are in the composition, the amphoteric or zwitterionic surfactant(s) are preferably present in a total amount ranging from 0.1% to 30% by weight, better still from 1% to 20% by weight and even more preferentially still from 2% to 15% by weight, relative to the total weight of the composition.

The composition according to the invention may also comprise one or more nonionic surfactants.

Examples of nonionic surfactants that may be used in the hair composition according to the invention are described, for example, in the Handbook of Surfactants by M.R. Porter, published by Blackie & Son (Glasgow and London), 1991, pp. 116-178. They are in particular chosen from polyethoxylated, polypropoxylated and/or polyglycerolated alcohols, a-diols and (Ci-C2o)alkylphenols, containing at least one fatty chain comprising, for example, from 8 to 18 carbon atoms, the number of

ethylene oxide and/or propylene oxide groups possibly ranging in particular from 2 to 50, and the number of glycerol groups possibly ranging in particular from 2 to 30.

Mention may also be made of condensates of ethylene oxide and of propylene oxide with fatty alcohols, polyethoxylated fatty amides preferably having from 2 to 30 ethylene oxide units, polyglycerolated fatty amides comprising on average from 1 to 5 glycerol groups, and in particular from 1.5 to 4, ethoxylated fatty acid esters of sorbitan containing from 2 to 30 ethylene oxide units, fatty acid esters of sucrose, fatty acid esters of polyethylene glycol, (C6-C24 alkyl)-mono- or -polyglycosides, N-(C6-C24 alkyl)glucamine derivatives, amine oxides such as (C10-C 14 alkyl)amine oxides or N-(C 10-C 14 acyl)aminopropylmorpho line oxides .

The nonionic surfactants that are particularly preferred are (C6-C24 alkyl)-mono- or -polyglycosides, and oxyalkylenated fatty alcohols.

When they are in the composition, the nonionic surfactant(s) are preferably present in a total amount ranging from 0.1% to 30% by weight, better still from 1% to 20% by weight and even more preferentially from 2% to 15% by weight, relative to the total weight of the composition.

Preferably, the cosmetic composition comprises a total amount of anionic, amphoteric, zwitterionic and nonionic surfactants ranging from 1% to 50% by weight, better still from 5% to 40% by weight and even more preferentially from 10% to 30% by weight, relative to the total weight of the composition.

The composition according to the invention may also comprise one or more non-silicone fatty substances, which are preferably liquid, other than the fatty acids according to the invention.

The term "non-silicone fatty substance" means an organic compound that is insoluble in water at ordinary temperature (25°C) and at atmospheric pressure (760 mmHg) (solubility less than 5% and preferably 1% and even more preferentially 0.1%). They bear in their structure at least one hydrocarbon-based chain comprising 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, ethanol, benzene, liquid petroleum jelly or decamethy Icy clopentasilo xane .

The term "oil" means a "fatty substance" that is liquid at room temperature (25°C) and at atmospheric pressure (760 mmHg or 1.013χ 105 Pa).

The term "non-silicone oil" means an oil not containing any silicon (Si) atoms.

More particularly, the fatty substances are chosen from C6-Ci6 hydrocarbons, hydrocarbons containing more than 16 carbon atoms, non-silicone oils of animal origin, triglycerides of plant or synthetic origin, fluoro oils, fatty alcohols, esters of fatty acids and/or of fatty alcohols other than triglycerides, non-silicone waxes other than solid fatty alcohols and than solid synthetic esters, and mixtures thereof.

It is recalled that, for the purposes of the invention, fatty alcohols, esters and acids more particularly bear at least one linear or branched, saturated or unsaturated hydrocarbon-based group comprising 6 to 30 carbon atoms, which is optionally substituted, in particular with one or more hydroxyl groups (in particular 1 to 4). If they are unsaturated, these compounds may comprise one to three conjugated or unconjugated carbon-carbon double bonds.

The linear or branched hydrocarbons of mineral or synthetic origin containing more than 16 carbon atoms are preferably chosen from liquid paraffins, liquid petroleum jelly, polydecenes and hydrogenated polyisobutene such as Parleam®, and mixtures thereof.

As regards the C6-Ci6 lower alkanes, they are linear or branched, or possibly cyclic.

Examples that may be mentioned include hexane, cyclohexane, undecane, dodecane, tridecane or isoparaffms, such as isohexadecane, isodecane or isododecane, and mixtures thereof.

A hydrocarbon-based oil of animal origin that may be mentioned is perhydrosqualene.

The triglycerides of plant or synthetic origin are preferably chosen from liquid fatty acid triglycerides containing from 6 to 30 carbon atoms, for instance heptanoic or octanoic acid triglycerides, or alternatively, more particularly from those present in plant oils, for instance sunflower oil, corn oil, soybean oil, marrow oil, grapeseed oil, sesame seed oil, hazelnut oil, apricot oil, macadamia oil, arara oil, castor oil, avocado oil, jojoba oil, shea butter oil or synthetic caprylic/capric acid triglycerides, for instance those sold by the company Stearineries Dubois or those sold under the names Miglyol® 810, 812 and 818 by the company Dynamit Nobel, and mixtures thereof.

The fluoro oils may be chosen from perfluoromethylcyclopentane and perfluoro-l,3-dimethylcyclo hexane, sold under the names Flutec® PCI and Flutec® PC3 by the company BNFL Fluorochemicals; perfluoro-l,2-dimethylcyclo butane; perfluoroalkanes such as dodecafluoropentane and tetradecafluorohexane, sold under

the names PF 5050® and PF 5060® by the company 3M, or alternatively bromoperfluorooctyl sold under the name Foralkyl® by the company Atochem; nonafluoromethoxybutane and nonafluoroethoxyisobutane; perfluoromorpholine derivatives such as 4-trifluoromethyl perfluoromorpholine sold under the name PF 5052® by the company 3M.

The fatty alcohols that are suitable for use in the invention are more particularly chosen from linear or branched, saturated or unsaturated alcohols comprising from 8 to 30 carbon atoms. Examples that may be mentioned include cetyl alcohol, stearyl alcohol and a mixture thereof (cetylstearyl alcohol), octyldodecanol, 2-butyloctanol, 2-hexyldecanol, 2-undecylpentadecanol, oleyl alcohol, linolenyl alcohol, ricinoleyl alcohol, undecylenyl alcohol and linoleyl alcohol, and mixtures thereof.

As regards the esters of fatty acids and/or of fatty alcohols other than the triglycerides mentioned above and plant waxes, mention may be made in particular of esters of saturated or unsaturated, linear Ci-C26 or branched C3-C26 aliphatic monoacids or polyacids and of saturated or unsaturated, linear Ci-C26 or branched C3-C26 aliphatic monoalcohols or polyalcohols, the total carbon number of the esters being greater than or equal to 6 and more advantageously greater than or equal to 10.

Among the monoesters, mention may be made of dihydroabietyl behenate; octyldodecyl behenate; isocetyl behenate; cetyl lactate; C12-C15 alkyl lactate; isostearyl lactate; lauryl lactate; linoleyl lactate; oleyl lactate; (iso)stearyl octanoate; isocetyl octanoate; octyl octanoate; cetyl octanoate; decyl oleate; isocetyl isostearate; isocetyl laurate; isocetyl stearate; isodecyl octanoate; isodecyl oleate; isononyl isononanoate; isostearyl palmitate; methyl acetyl ricinoleate; myristyl stearate; octyl isononanoate; 2-ethylhexyl isononanoate; octyl palmitate; octyl pelargonate; octyl stearate; octyldodecyl erucate; oleyl erucate; ethyl and isopropyl palmitates, 2-ethylhexyl palmitate, 2-octyldecyl palmitate, alkyl myristates such as isopropyl, butyl, cetyl, 2-octyldodecyl, myristyl or stearyl myristate, hexyl stearate, butyl stearate, isobutyl stearate; dioctyl malate, hexyl laurate, 2-hexyldecyl laurate, and mixtures thereof.

Still within the context of this variant, esters of C4-C22 dicarboxylic or tricarboxylic acids and of Ci-C22 alcohols and esters of mono-, di- or tricarboxylic acids and of C2-C26 di-, tri-, tetra- or pentahydroxy alcohols may also be used.

Mention may be made in particular of: diethyl sebacate; diisopropyl sebacate; diisopropyl adipate; di-n-propyl adipate; dioctyl adipate; diisostearyl adipate; dioctyl maleate; glyceryl undecylenate; octyldodecyl stearoyl stearate; pentaerythrityl

monoricinoleate; pentaerythrityl tetraisononanoate; pentaerythrityl tetrapelargonate; pentaerythrityl tetraisostearate; pentaerythrityl tetraoctanoate; propylene glycol dicaprylate; propylene glycol dicaprate; tridecyl erucate; triisopropyl citrate; triisostearyl citrate; glyceryl trilactate; glyceryl trioctanoate; trioctyldodecyl citrate; trioleyl citrate; propylene glycol dioctanoate; neopentyl glycol diheptanoate; diethylene glycol diisononanoate; and polyethylene glycol distearates, and mixtures thereof.

Among the esters mentioned above, it is preferred to use ethyl, isopropyl, myristyl, cetyl or stearyl palmitate, 2-ethylhexyl palmitate, 2-octyldecyl palmitate, alkyl myristates such as isopropyl, butyl, cetyl or 2-octyldodecyl myristate, hexyl stearate, butyl stearate, isobutyl stearate, dioctyl malate, hexyl laurate, 2-hexyldecyl laurate, isononyl isononanoate or cetyl octanoate, and mixtures thereof.

The composition may also comprise, as 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 bearing several alcohol functions, with or without aldehyde or ketone functions, and which comprise at least 4 carbon atoms. These sugars may be monosaccharides, oligosaccharides or polysaccharides.

Examples of suitable sugars that may be mentioned include sucrose (or saccharose), glucose, galactose, ribose, fucose, maltose, fructose, mannose, arabinose, xylose and lactose, and derivatives thereof, especially 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 of sugar esters described previously and of linear or branched, saturated or unsaturated C6-C30 and preferably C12-C22 fatty acids. If they are unsaturated, these compounds may comprise one to three conjugated or unconjugated carbon-carbon double bonds.

The esters according to this variant may also be chosen from mono-, di-, tri-and tetraesters, polyesters, and mixtures thereof.

These esters may be, for example, oleates, laurates, palmitates, myristates, behenates, cocoates, stearates, linoleates, linolenates, caprates and arachidonates, or mixtures thereof such as, especially, oleopalmitate, oleostearate and palmitostearate mixed esters.

More particularly, use is made of monoesters and diesters and especially sucrose, glucose or methylglucose monooleate or dioleate, stearate, behenate, oleopalmitate, linoleate, linolenate or oleostearate.

An example that may be mentioned is the product sold under the name Glucate® DO by the company Amerchol, which is a methylglucose dioleate.

Examples of esters or mixtures of esters of sugar and of fatty acid that may also be mentioned include:

- the products sold under the names F160, F140, Fl 10, F90, F70 and SL40 by the company Crodesta, respectively denoting sucrose palmitostearates formed from 73% monoester and 27% diester and triester, from 61% monoester and 39% diester, triester and tetraester, from 52% monoester and 48% diester, triester and tetraester, from 45% monoester and 55% diester, triester and tetraester, from 39% monoester and 61 ) diester, triester and tetraester, and sucrose monolaurate;

- the products sold under the name Ryoto Sugar Esters, for example referenced B370 and corresponding to sucrose behenate formed from 20%> monoester and 80%> di-triester-polyester;

- the sucrose mono-dipalmito-stearate sold by the company Goldschmidt under the name Tegosoft® PSE.

The non- silicone wax(es) other than solid fatty alcohols and solid synthetic esters are chosen in particular from carnauba wax, candelilla wax, esparto wax, paraffin wax, ozokerite, plant waxes, such as olive tree wax, rice wax, hydrogenated jojoba wax or absolute flower waxes, such as the blackcurrant blossom essential wax sold by the company Bertin (France), or animal waxes, such as beeswaxes or modified beeswaxes (cerabellina); other waxes or waxy raw materials that may be used according to the invention are in particular marine waxes, such as the wax sold by the company Sophim under the reference M82, polyethylene waxes or polyolefin waxes in general.

The fatty substance(s) do not comprise any C2-C3 oxyalkylene units. Preferably, they do not contain any glycerol units.

More particularly, the fatty substances are chosen from compounds that are liquid or pasty at room temperature and at atmospheric pressure.

Preferably, the fatty substance is a compound that is liquid at a temperature of 25°C and at atmospheric pressure, or oil.

Preferably, the non-silicone fatty substance(s) other than fatty acids are chosen from oils of plant origin, fatty esters, and mixtures thereof, better still from oils of plant origin and liquid fatty esters, and mixtures thereof.

Even more preferentially, the non-silicone fatty substance(s) other than fatty acids are chosen from oils of plant origin, better still from sunflower oil and avocado oil.

When they are in the composition, the non-silicone fatty substance(s) are preferably present in an amount ranging from 0.1% to 30% by weight, better still from 0.5% to 20% by weight and even more preferentially from 1% to 10% by weight, relative to the total weight of the composition.

The composition according to the invention may also comprise one or more cationic polymers.

The term "cationic polymer" means any polymer comprising cationic groups and/or groups that can be ionized to cationic groups. Preferably, the cationic polymer is hydrophilic or amphiphilic. The preferred cationic polymers are chosen from those that contain units comprising primary, secondary, tertiary and/or quaternary amine groups that may either form part of the main polymer chain or may be borne by a side substituent directly connected thereto.

The cationic polymers that may be used preferably have a weight-average molar mass (Mw) of between 500 and 5x 106 approximately and preferably between 103 and 3x 106 approximately.

Among the cationic polymers, mention may be made more particularly of: (1) Homopolymers or copolymers derived from acrylic or methacrylic esters or amides and comprising at least one of the units of the following formulae:

in which:

- R3, which may be identical or different, denote a hydrogen atom or a CH3 group;

- A, which may be identical or different, represent a linear or branched divalent alkyl group of 1 to 6 carbon atoms, preferably 2 or 3 carbon atoms, or a hydroxyalkyl group of 1 to 4 carbon atoms;

- P4, R-5 and R^, which may be identical or different, represent an alkyl group containing from 1 to 18 carbon atoms or a benzyl group, and preferably an alkyl group containing from 1 to 6 carbon atoms;

- Ri and R2, which may be identical or different, represent a hydrogen atom or an alkyl group containing from 1 to 6 carbon atoms, and preferably methyl or ethyl;

- X denotes an anion derived from a mineral or organic acid, such as a methosulfate anion or a halide such as chloride or bromide.

The copolymers of family (1) may also contain one or more units derived from comonomers which may be chosen from the family of acrylamides, methacrylamides, diacetone acrylamides, acrylamides and methacrylamides substituted on the nitrogen with C1-C4 alkyls, acrylic or methacrylic acids or esters thereof, vinyllactams such as vinylpyrrolidone or vinylcaprolactam, and vinyl esters.

Among these copolymers of family (1), mention may be made of:

- copolymers of acrylamide and of dimethylaminoethyl methacrylate quaternized with dimethyl sulfate or with a dimethyl halide, such as that sold under the name Hercofloc by the company Hercules,

- copolymers of acrylamide and of methacryloyloxyethyltrimethylammonium chloride, such as the product sold under the name Bina Quat P 100 by the company Ciba Geigy,

the copolymer of acrylamide and of

methacryloyloxyethyltrimethylammonium methosulfate, such as that sold under the name Reten by the company Hercules,

- quaternized or non-quaternized vinylpyrrolidone/dialkylaminoalkyl acrylate or methacrylate copolymers, such as the products sold under the name Gafquat by the company ISP, for instance Gafquat 734 or Gafquat 755, or alternatively the products known as Copolymer 845, 958 and 937. These polymers are described in detail in French patents 2 077 143 and 2 393 573,

dimethylaminoethyl methacrylate/vinylcaprolactam/vinylpyrrolidone terpolymers, such as the product sold under the name Gaffix VC 713 by the company ISP,

- vinylpyrrolidone/methacrylamidopropyldimethylamine copolymers, such as the product sold under the name Styleze CC 10 by ISP,

quaternized vinylpyrrolidone/dimethylaminopropylmethacrylamide copolymers such as the product sold under the name Gafquat HS 100 by the company ISP,

- preferably crosslinked polymers of methacryloyloxy(Ci-C4)alkyl tri(Ci-C4)alkylammonium salts, such as the polymers obtained by homopolymerization of dimethylaminoethyl methacrylate quaternized with methyl chloride, or by copolymerization of acrylamide with dimethylaminoethyl methacrylate quaternized with methyl chloride, the homo- or copolymerization being followed by crosslinking with an olefmically unsaturated compound, in particular methylenebisacrylamide. Use may be made more particularly of a crosslinked acrylamide/methacryloyloxyethyltrimethylammonium chloride copolymer (20/80 by weight) in the form of a dispersion comprising 50% by weight of said copolymer in mineral oil. This dispersion is sold under the name Salcare® SC 92 by the company Ciba. Use may also be made of a crosslinked methacryloyloxyethyltrimethylammonium chloride homopolymer comprising approximately 50% by weight of the homopolymer in mineral oil or in a liquid ester. These dispersions are sold under the names Salcare® SC 95 and Salcare® SC 96 by Ciba.

(2) Cationic polysaccharides, in particular cationic celluloses and cationic galactomannan gums. Among the cationic polysaccharides, mention may be made more particularly of cellulose ether derivatives comprising quaternary ammonium groups, cationic cellulose copolymers or cellulose derivatives grafted with a water-soluble quaternary ammonium monomer and cationic galactomannan gums.

The cellulose ether derivatives comprising quaternary ammonium groups are in particular described in FR 1 492 597, and mention may be made of the polymers sold under the name Ucare Polymer JR (JR 400 LT, JR 125 and JR 30M) or LR (LR 400 and LR 30M) by the company Amerchol. These polymers are also defined in the CTFA dictionary as quaternary ammoniums of hydroxy ethylcellulose that have reacted with an epoxide substituted with a trimethylammonium group.

Cationic cellulose copolymers or cellulose derivatives grafted with a water-soluble quaternary ammonium monomer are described in particular in US patent 4 131 576, and mention may be made of hydro xyalkyl celluloses, for instance hydroxymethyl-, hydroxyethyl- or hydroxypropylcelluloses grafted, in particular, with a methacryloylethyltrimethylammonium, methacrylamidopropyltrimethylammonium or dimethyldiallylammonium salt. The commercial products corresponding to this definition are more particularly the products sold under the names Celquat L 200 and Celquat H 100 by the company National Starch.

The cationic galactomannan gums are described more particularly in patents US 3 589 578 and US 4 031 307, and mention may be made of guar gums comprising cationic trialkylammonium groups. Use is made, for example, of guar gums modified with a 2,3-epoxypropyltrimethylammonium salt (for example, a chloride). Such products are in particular sold under the names Jaguar C13 S, Jaguar C 15, Jaguar C 17 and Jaguar CI 62 by the company Rhodia.

(3) Polymers composed of piperazinyl units and of divalent alkylene or hydroxyalkylene groups containing linear or branched chains, optionally interrupted with oxygen, sulfur or nitrogen atoms or with aromatic or heterocyclic rings, and also the oxidation and/or quaternization products of these polymers.

(4) Water-soluble polyaminoamides prepared in particular by poly condensation of an acidic compound with a polyamine; these polyaminoamides can be crosslinked with an epihalohydrin, a diepoxide, a dianhydride, an unsaturated dianhydride, a bis-unsaturated derivative, a bis-halohydrin, a bis-azetidinium, a bis-haloacyldiamine, a bis-alkyl halide or alternatively with an oligomer resulting from the reaction of a difunctional compound which is reactive with a bis-halohydrin, a bis-azetidinium, a bis-haloacyldiamine, a bis-alkyl halide, an epihalohydrin, a diepoxide or a bis-unsaturated derivative; the crosslinking agent being used in proportions ranging from 0.025 to 0.35 mol per amine group of the polyaminoamide; these polyaminoamides can be alkylated or, if they comprise one or more tertiary amine functions, they can be quaternized.

(5) Polyaminoamide derivatives resulting from the condensation of polyalkylene polyamines with polycarboxylic acids followed by alkylation with difunctional agents. Mention may be made, for example, of adipic acid/dialkylamino hydroxy alky ldialkylenetriamine polymers in which the alkyl group comprises from 1 to 4 carbon atoms and preferably denotes methyl, ethyl or propyl. Among these derivatives, mention may be made more particularly of the adipic acid/dimethylaminohydroxypropyl/diethylenetriamine polymers sold under the name Cartaretine F, F4 or F8 by the company Sandoz.

(6) Polymers obtained by reacting a polyalkylene polyamine comprising two primary amine groups and at least one secondary amine group with a dicarboxylic acid chosen from diglycolic acid and saturated aliphatic dicarboxylic acids containing from 3 to 8 carbon atoms; the mole ratio between the polyalkylene polyamine and the dicarboxylic acid preferably being between 0.8: 1 and 1.4: 1; the resulting polyamino amide being reacted with epichlorohydrin in a mole ratio of epichlorohydrin relative to the secondary amine group of the polyamino amide preferably of between 0.5: 1 and 1.8: 1. Polymers of this type are sold in particular under the name Hercosett 57 by Hercules Inc. or else under the name PD 170 or Delsette 101 by Hercules in the case of the adipic acid/epoxypropyl/diethylenetriamine copolymer.

CLAIMS
1. Cosmetic composition, comprising:
(i) one or more anionic surfactants,
(ii) at least 3.5% by weight of one or more fatty acids, relative to the total weight of the composition, and
(iii) one or more antidandruff agents,
the anionic surfactant(s)/fatty acid(s) weight ratio being from 0.5 to 3.5.

2. Cosmetic composition according to Claim 1 , characterized in that the anionic surfactant(s) are chosen from (Ci2-C2o)alkyl sulfates, (Ci2-C2o)alkyl ether sulfates comprising from 1 to 20 ethylene oxide units, especially in the form of salts of alkali metals, of ammonium, of amino alcohols and of alkaline-earth metals, preferably from sodium or ammonium lauryl sulfate and sodium lauryl ether sulfate.

3. Cosmetic composition according to Claim 1 or 2, characterized in that the anionic surfactant(s) are present in an amount ranging from 0.1% to 40% by weight, preferably ranging from 1% to 30% by weight, better still from 10% to 20% by weight and preferentially from 1 1% to 15% by weight, relative to the total weight of the composition.

4. Cosmetic composition according to any one of the preceding claims, characterized in that the fatty acid(s) are chosen from linear fatty acids, better still from saturated linear Cio-C22 fatty acids, and better still lauric acid.

5. Cosmetic composition according to any one of the preceding claims, characterized in that the fatty acid(s) are present in an amount ranging from 3.5% to 30%) by weight, preferably from 3.5% to 20%> by weight, better still from 3.75% to 15% by weight and even better still from 4% to 8% by weight, relative to the total weight of the composition.

6. Cosmetic composition according to any one of the preceding claims, characterized in that it has an anionic surfactant(s)/fatty acid(s) weight ratio ranging from 1 to 3 and more preferentially from 1.5 to 3.

7. Cosmetic composition according to any one of the preceding claims, characterized in that the antidandruff agent(s) are chosen from pyridinethione salts, l-hydroxy-2-pyrrolidone derivatives, 2,2'-dithiobis(pyridine N-oxide), selenium sulfides, and mixtures thereof, and preferably from zinc pyridinethione, (1 -hydroxy- 4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone and salts thereof, and selenium sulfides, and mixtures thereof.

8. Cosmetic composition according to any one of the preceding claims, characterized in that the antidandruff agent(s) are present in an amount ranging from 0.01% to 20% by weight, more preferentially from 0.1% to 10% by weight and better still from 0.2% to 5% by weight, relative to the total weight of the composition.

9. Cosmetic composition according to any one of the preceding claims, characterized in that it comprises one or more amphoteric or zwitterionic surfactants, chosen especially from (Cs-C2o)alkyl betaines and (C8-C2o)alkylamido(Ci-C6)alkyl betaines, preferably in an amount ranging from 0.1% to 30% by weight, better still from 1% to 20% by weight and even more preferentially from 2% to 15% by weight, relative to the total weight of the composition.

10. Cosmetic composition according to any one of the preceding claims, characterized in that it comprises one or more nonionic surfactants, chosen especially from (C6-C24 alkyl)-mono- or -polyglycosides, and oxyalkylenated fatty alcohols, preferably in an amount ranging from 0.1% to 30% by weight, better still from 1% to 20% by weight and even more preferentially from 2% to 15% by weight, relative to the total weight of the composition.

11. Cosmetic composition according to any one of the preceding claims, characterized in that it comprises one or more non-silicone fatty substances other than fatty acids, which are preferably liquid, preferentially chosen from oils of plant origin and liquid fatty esters, better still chosen from oils of plant origin.

12. Cosmetic composition according to any one of the preceding claims, characterized in that it comprises one or more cationic polymers, preferably cationic polysaccharides, preferentially in an amount ranging from 0.01% to 10% by weight, better still from 0.05% to 5% by weight and even more preferentially from 0.1% to 2% by weight, relative to the total weight of the composition.

13. Cosmetic composition according to any one of the preceding claims, characterized in that it comprises one or more silicones, preferably aminosilicones, preferentially in an amount ranging from 0.01% to 10% by weight, better still from 0.05% to 5% by weight and even more preferentially from 0.1% to 2% by weight, or even between 0.15% and 1.5% by weight, relative to the total weight of the composition.

14. Cosmetic process for treating, and more particularly for washing and conditioning, keratin fibres, especially human keratin fibres and in particular the hair, characterized in that it comprises the application to said fibres of an effective amount of a cosmetic composition according to any one of the preceding claims, followed by rinsing and drying.