Solid depilatory composition containing a particulate structuring agent

1 The present invention relates to a new depilatory composition having the appearance of a deformable solid.

Because of its extreme softness, this composition can be applied both to the face and to the body, and in particular around the lips, on the arms, on the legs and under the armpits.

The invention also relates to a cosmetic treatment process for the removal of excess hair.

The invention also relates to the use of a particular structuring agent in a depilatory composition.

Apart from mechanical hair removal means such as razors, depilatory methods currently used consist in applying depilatory compositions to depilatory parts such as waxes or depilatory creams.

We apply the waxes, most often after having melted them, then we remove them after a certain exposure time, which thus leads to the pulling of the hairs. Waxing is awkward when handling hot wax, and it is also painful because the hairs are pulled out violently when the hardened wax is removed.

In addition, the hair removal obtained is not always satisfactory.

In a simplified manner, a depilatory cream comprises a hair softening agent, most often a thiol, in a cosmetically acceptable support or medium of high pH, ​​for example of the order of 12 or 12.5.

The depilatory cream is applied cold and makes the hairs fall, softening them.

Depilatory creams are difficult to dose due to their fluidity and often give incomplete hair removal.

In addition, after each hair removal treatment, it is necessary to remove the depilatory cream and rinse the area of ​​depilated skin and, unfortunately, many depilatory creams have the disadvantage of being difficult to remove and / or leave traces of products on the skin.

In addition, whatever the hair removal technique chosen, it is most often irritating to the skin.

In addition, users are increasingly looking for new textures and new product concepts.

The subject of the present invention is precisely a new depilatory composition which in particular makes it possible to remedy the drawbacks mentioned above.

In particular, this composition rinses remarkably and has a completely unusual texture.

In addition, it is simple to apply.

Surprisingly, the Applicant has found that it is possible to give a depilatory composition the appearance of a deformable solid using an original structuring or texturing agent.

21 53455 2 Thus, the invention relates to a depilatory composition, characterized in that it contains, in a cosmetically acceptable medium:

a) an agent which softens the hairs in sufficient quantity to cause the hairs to fall out; and b) a structuring agent which is insoluble in the medium, said agent being composed of solid particles present in a concentration at least equal to the critical volume charge pigment in order to give the composition an appearance of deformable solid in which the medium is trapped, this agent being able to be removed from the skin by means of a diluent.

Another subject of the invention is the use of a structuring agent in a depilatory composition to give it an appearance of a deformable solid, this agent being composed of solid particles present in a concentration at least equal to the critical volume charge pigment in order to give the composition an appearance of a deformable solid, this agent being capable of being removed from the skin by means of a diluent.

One of the advantages of this solid texture is that the composition of the invention does not run the risk of escaping from its packaging, in particular during its transport.

Furthermore, this composition is very easy to grip and does not flow between the fingers.

Its dosage is much simpler than that of the usual creams.

According to the invention, the composition is in the form of a deformable solid, dry, not staining and resembling marshmallow (see document US-A-3,682,659 for the consistency of marshmallow).

This solid can be molded like children's play dough. It can be easily broken by hand in order to take only the necessary quantity of product.

In particular, this composition can be packaged in the form of a single dose and for example in the form of small cubes, marbles or berlingots.

A 21 5345 5 3 Thanks to the particles of the invention, it is in particular possible to obtain a homogeneous structure (deformable solid) for constituents normally leading to two distinct phases (immiscible constituents, for example oil / water).

In order to obtain a solid with a pleasant and soft touch, it is preferable to use particles having a particle size of 1 ~ .m to 300 ~ Cm, for example from 5 ~ .m to 200 ~, m and preferably of 10 ~ Cm to 100 ~ Cm and better from 15 ~, m to 40 ~ .m.

The great softness provided by these particles allows the use of the depilatory composition of the invention for people with sensitive skin.

In order to give the composition of the invention an airy and light appearance, it is advantageous to use particles having a density of less than 0.09 g / cm3 and better still less than 0.06 g / cm3 and even better still less than 0.04 g / cm3.

In order to obtain this low density, hollow particles filled with a gas are advantageously used.

This gas can be air, nitrogen, isobutane, isopentane, etc.

According to another advantageous characteristic of the invention, the particles are in the form of beads. It is however possible to use particles in the form of fibers.

These particles can be produced from different inert materials which do not react chemically with the cosmetically acceptable medium or support; in particular, these particles do not react with oils, surfactants, water and the various other constituents of the composition, such as the active agents.

The texturing agent of the invention has the particularity of B 21 5345 5 4 being easily removed from the skin by simple dilution. I1 actually plays the role of vehicle or reservoir for the cosmetic support. I1 also makes it possible to recover the support and in particular the active agent (s) trapped in the deformable solid, when necessary by simple dilution with water.

This is probably due to the fact that the cosmetic support is housed in the interparticle spaces of the solid and not in the particles.

In addition to water, water added with one or more polar solvents such as lower alcohols (ethanol, isopropanol) and glycols (propylene glycol), of one or more surfactants can be used as diluent.

It is also possible to use water loaded with salts.

As a criterion for choosing the texturing agent, the following test can be carried out:

- addition of specific particles in water containing a dye conventionally used in the depilatory field such as azulene, until a colored paste is obtained, - pouring of a drop of water on the paste.

When the paste at the point of impact of the drop of water is much lighter than the rest of the paste, this means that the particles considered are candidates as a texturing agent.

Conversely, when the paste at the point of impact has not become discolored, the particles considered are in no way suitable.

The inert particles are advantageously made of glass or of thermoplastic materials such as polyamides such as nylon, polymers or copolymers of acrylonitrile, vinylidene chloride, vinyl chloride and / or acrylic or styrenic monomer, optionally expanded.

The acrylic monomer 2153455 is for example a methyl or ethyl acrylate or methacrylate.

The styrenic monomer is for example α-methyl-styrene or styrene.

As glass particles which can be used in the invention, mention may be made of the hollow glass beads sold by the company 3M under the reference Scotchlite Glass Bubbles * S 22.95 of these beads have a diameter of less than 74 μm.

As nylon particles, use may be made of "Orgasol *" particles sold by the company Atochem.

These particles are solid, porous spheres with a diameter ranging from 5 ~ cm to 60 ~ .m.

Preferably, the particles are deformable hollow particles of an expanded copolymer of vinylidene chloride and acrylonitrile or vinylidene chloride, acrylonitrile and methacrylate.

It is possible, for example, to use a copolymer containing: from 0 to 60 from units derived from vinylidene chloride, from 20 ~ to 90 from units derived from acrylonitrile and from 0 to 50 from units derived from an acrylic or styrenic monomer, the sum of the percentages (by weight) being equal to 100.

These particles are present in particular in the dry or hydrated state and can be obtained, for example, according to the methods described in the patents and patent applications EP-A-56,219, EP-A-348,572, EP-A-320 473, EP-A-112,807 and US-A-3,615,972.

These hollow particles may for example be those formed of a terpolymer of acrylonitrile, methacrylate and vinylidene chloride and sold under the brand name EXPANCEL * by the company Nobel Casco, and in particular under the references * (trademarks), w 21 53 455 6 551 DE 12 (particle size about 12 ~ .m and density 40 kg / m3), 551 DE 20 (particle size about 30 ~, m and density 65 kg / m3), 551 DE 50 ( particle size of about 40 ~ im).

It is also possible to use particles formed of the same terpolymer and having a particle size of approximately 18 μm and a density of approximately 60 to 80 kg / m3, called here EL 23, or having a particle size of approximately 34 ~ .m and a density of approximately 20 kg / m3, here called EL 43, or having a particle size of approximately 150 ~, m, here called EL 55.

As other polymeric hollow particles which can be used in the invention, mention may also be made of the polymers and copolymers obtained from esters or acids, itaconic, citraconic, malefic, fumaric, vinyl acetate or lactate (see for this purpose the document JP-A-2-112304), or also particles of unexpanded copolymer of vinylidene chloride and acrylonitrile or of vinylidene chloride, acrylonitrile and methacrylate, sold under the brand 20 EXPANCEL * with the reference 551 WU.

On the other hand, the particles of corn starch, fumed silica, polyethylene, polyurethane or unexpanded polyester do not make it possible to obtain a solid composition which is removed well from the skin during rinsing.

It is certainly known to modify the viscosity of a liquid medium with solid particles (on this subject see the article Elsevier Sequoia, 1992, Progress in Organic Coatings, 21, 30 p.255-267, by A.

All Saints Day "Choice of rheological model for steady flow: application to industrial concentrated suspensions") but no one to date has neither described nor suggested using the solid product, obtained from a certain concentration of particles, in the depilatory area for * (trademark) 21 53455 to store the medium in which the particles are dispersed.

In other words, whether or not the deformable solid is obtained is linked to the amount of structuring agent used in the composition;

above a certain quantity of particles, called critical pigment charge and denoted CPVC, there is a sudden increase in the viscosity of the medium.

The CPVC is a function of the medium and the nature of the particles and must therefore be determined each time. its determination poses no problem for those skilled in the art.

One can, for example, use the official ASTM method to determine the CPVC.

Another subject of the invention is the use of the composition defined above for the removal of hair.

Thus, the subject of the invention is also a process for hair removal from the skin, consisting in applying to the skin a composition as defined above, then in rinsing the skin.

The composition of the invention contains, in addition to the texturing particles, all the constituents conventionally used in depilatory compositions.

These constituents are in particular hair softening agents such as thiols and in particular calcium thioglycolate, mineral, vegetable, synthetic or silicone oils, water, alcoholic solvents, filters, perfumes, surfactants, polymers, preservatives, antioxidants, 3o pH regulating agents, sequestrants, fillers etc.

The example below is given by way of illustration and not limitation in order to better highlight the characteristics of the invention.

21 53455 g EXAMPLE: DEPILATORY PASTE - Calcium thioglycolate 8 - Cetylstearyl alcohol / oxyethylenated cetylstearyl alcohol (33 OE) (80/20 mixture sold under the name Lanol ​​CTO * wax by the company Seppic) (emulsifier) ​​- Anhydrous calcium oxide ( load) 3 ~ - EXPANCEL * 551 DE 20 3 ô l0 - Water qs 100 ~ We obtain a smooth white paste, with a soft touch, easily moldable, easy to apply and remove.

The particles have the advantage, moreover, of strongly absorbing the odor of the thiols, which gives the composition a much weaker odor than that of the depilatory compositions of the prior art.

20 This preparation is applied, in particular by hand, to the part to be epilated.

Leave to act for 10 minutes, then rinse thoroughly with water.

There is very good hair removal without any irritation problem.

* (trademarks)