CROSS REFERENCE TO RELATED APPLICATIONS

This is a national stage application of PCT/EP2016/080799, filed internationally on Dec. 13, 2016, which claims priority to French Application No. 1562405, filed on Dec. 15, 2015, both of which are incorporated by reference herein in their entireties.

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.

