WO2021069807A1

WO2021069807A1 - Cosmetic composition, method for preparation and use of same as a mask for the cosmetic treatment of skin, particularly the face

Info

Publication number: WO2021069807A1
Application number: PCT/FR2019/052395
Authority: WO
Inventors: Alexis LIARD
Original assignee: S.A. Thalgo Tch
Priority date: 2019-10-09
Filing date: 2019-10-09
Publication date: 2021-04-15

Abstract

The invention relates mainly to a cosmetic composition for a peelable mask for the cosmetic treatment of skin, particularly the face, characterised in that it comprises at least one wax or a blend of waxes, and at least one thermoplastic polymer or a blend of thermoplastic polymers.

Description

DESCRIPTION

TITLE: Cosmetic composition, production process and use as a mask for cosmetic treatment of the skin, especially the face

TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of cosmetic compositions, and more particularly cosmetic compositions used as a mask for cosmetic treatment of the skin, in particular of the face.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] Beauty masks are well known from the prior art. These masks are products intended to be applied to an area of the body, most often the face, and to be left in place for a specified period of time, usually around 10 to 15 minutes, and then removed.

[0003] Among the existing masks, a distinction is made between cream-masks which act as a cosmetic cream by being applied in a thick layer, tissue-masks which are in the form of supports impregnated with a cosmetic formula, lotion, gel or emulsion. , which contains the active agents, or the hydrogels made up of natural polymers combined with water to form a fresh film-forming gel exhibiting good adhesion and an occlusive effect ensuring the penetration of the active ingredients.

[0004] There is also a category of so-called peel-off masks, also and commonly referred to by the Anglo-Saxon term "peel-off". These peel-off masks are liquid during application and then become sufficiently solid on drying to be able to be removed in one or more pieces. During the drying time, the mask provides hydration to the skin and can also promote the penetration of active agents, for example included in the mask. In addition, the coat helps to remove dead skin cells. Several categories of physical hardening masks are known. In particular, masks based on polymers dissolved in a solvent or in water, for example polyvinyl alcohol in water, which solidify by evaporation of the solvent or of water, are known. To avoid too long an evaporation time (and therefore exposure to the face), the film must be thin enough which makes it fragile and can lead to tearing the hair or down on the face. Cellulose-based masks are also known for which a cellulose polymer is dissolved in water, and which also solidify by evaporation of water. As for the masks based on solubilized polymers, these necessarily thin masks are fragile. Finally, masks of the alginate type are known which form hard gels by supplying divalent cations, such as calcium, or trivalent cations. The majority of alginate masks are in powder form to which water containing calcium must be added to obtain a paste. There are thus risks of inhalation of alginate powders by professionals.

The invention provides a mask overcoming the aforementioned drawbacks, with physical hardening applicable in a thick layer and making it possible to maintain a suitable temperature on the skin during its exposure time to ensure hydration of the skin, as well as, if necessary effective diffusion of active agents present either directly in the composition or previously applied to the skin. The mask-forming composition of the invention should also exhibit homogeneous solidification over its entire surface and be easily removed, preferably in one piece.

SUMMARY OF THE INVENTION

In this context, the invention relates firstly to a cosmetic composition for a peelable mask for cosmetic treatment of the skin, in particular of the face, which is essentially characterized in that it comprises at least one wax or a mixture of waxes, and at least one thermoplastic polymer or a mixture of thermoplastic polymers.

[0008] The composition of the invention can also include the following optional characteristics considered in isolation or according to all the possible technical combinations: the wax or the mixture of waxes has a melting point of less than 80 ° C, preferably less than 70 ° C; the wax or the mixture of waxes has a melting point greater than or equal to 55 ° C, and the content by mass of polymer or mixture of polymers in the composition is greater than or equal to 20%, alternatively, the wax or the mixture of waxes have a melting point of less than 55 ° C, and the content by mass of polymer or mixture of polymers in the composition is less than 20%. in the latter case, preferably, the mass content of polymer or mixture of polymers in the composition is less than 10%, the wax is beeswax, microcrystalline wax, paraffin wax or a mixture of these waxes. the thermoplastic polymer is an ethylene vinyl acetate copolymer, an ethylene octene copolymer, an ethylene butylene styrene copolymer, an ethylene propylene styrene copolymer, or a mixture of these copolymers; the wax is a paraffin wax with a melting point of less than 55 ° C, the content by mass of polymer or mixture of polymers in the composition is less than 20% and the thermoplastic polymer is an ethylene butylene styrene copolymer, a copolymer ethylene propylene styrene or a mixture of these two copolymers;

- In the latter case, preferably, the thermoplastic polymer is a mixture of ethylene butylene styrene copolymer, and of ethylene propylene styrene copolymer. the composition further comprises a fatty substance or a mixture of fatty substances of the oil or butter type; the composition constitutes a mask for cosmetic treatment of the skin, in particular of the face.

[0009] Another aspect of the invention relates to the use of the composition as stated above, as a peelable mask for cosmetic treatment of the skin, in particular of the face.

Advantageously, said use comprises at least the steps of: applying the mask to the skin, and removing the mask by peeling off after leaving the mask on the skin for a determined period of time.

A last aspect of the invention relates to the process for producing a peelable mask for cosmetic treatment of the skin, in particular of the face, from the composition as previously stated, which process comprises at least the steps of : mixture of at least one wax or a mixture of waxes, and a thermoplastic polymer or a mixture of thermoplastic polymers; increase in the temperature of the mixture to a temperature between 110 and 200 ° C, preferably between 120 and 180 ° C, and obtaining a homogeneous mixture, decrease in the temperature of the mixture to a temperature between 70 and 90 ° C, casting of the mask for a period greater than or equal to 2 hours, and cooling to room temperature

Advantageously, the wax of the composition is a paraffin wax, the thermoplastic polymer is an ethylene butylene styrene copolymer, an ethylene propylene styrene copolymer or a mixture of these two copolymers, increasing the temperature of the mixing is carried out up to a temperature between 150 and 170 ° C, the temperature is reduced until a temperature between 75 and 95 ° C is reached, and the casting is carried out for a period greater than or equal to 3 hours .

The invention and its various applications will be better understood on reading the following description. DETAILED DESCRIPTION

The Applicant has surprisingly found that the only combination of wax, or of a mixture of waxes, and of a thermoplastic polymer, or of a mixture of thermoplastic polymer, makes it possible to produce a peel-off mask at easy to apply and remove physical hardening. The composition of the invention takes advantage of the known properties of waxes (plasticity, viscosity, melting point temperature, hydrophobicity) while improving certain characteristics, in particular the flexibility of the mixture on spreading as well as the thermal inertia of the mixture. , by the presence of thermoplastic polymers.

According to the invention, the term "wax" means a lipophilic compound, solid at room temperature (25 ° C), exhibiting a reversible solid / liquid change of state, and having a melting / freezing point of between 30 and 120 ° C. The waxes capable of being used can be chosen from plant, animal, mineral or synthetic waxes, and mixtures thereof.

[0016] In particular, beeswax, microcrystalline wax, paraffin wax, Ozokerite, Carnauba wax, Candelilla wax or a mixture thereof can be used.

Preferably, the wax or the mixture of waxes has a melting point of less than 80 ° C to allow application to the skin at a temperature ensuring both a suitable application viscosity and comfort for the user. . More preferably, the melting point is less than 70 ° C and advantageously less than 60 ° C. Preferably a wax is chosen whose mechanical properties at 30-32 ° C (average skin temperature) are suitable for use as a peel-off mask in terms of suppleness, flexibility and resistance to tearing. As such, microcrystalline waxes and paraffin wax are preferred, which offer the most flexibility and tear resistance.

The amount of wax or mixture of waxes can vary between 15 and 95% by weight of the composition depending on the polymer (s) used and depending on the temperature of melting point of the wax or of the mixture of waxes for reasons which will be detailed below. Preferably, the content by mass of wax or of a mixture of waxes is greater than 20%, and more preferably greater than 40%, to give the composition forming a mask the character and properties specific to waxes.

To use the wax or the mixture of waxes as an application product on the face, the flexibility of application of the composition to the face must be optimized. To do this and according to the invention, the wax is mixed with one or more polymers whose hot melt index is relatively high and whose softening point is less than 80 ° C, in order to give the composition maximum fluidity. to facilitate hot spreading on the skin without risk of burns. The polymer must also exhibit poor adhesion properties for obvious reasons of comfort when removing the mask.

The amount of polymer or mixture of polymers can vary between 2 and 50% by weight of the composition depending on the amount of wax or mixture of waxes used and also depending on the nature of the wax (s) used.

More preferably, when the wax or the mixture of waxes has a melting point greater than or equal to 55 ° C and less than 80 ° C, the content by mass of polymer or mixture of polymers in the composition will be chosen greater than or equal to at 20%. This content makes it possible to modulate the kinetics of cooling of the wax and allow its application to the skin without burning while giving it satisfactory spreading properties, flexibility and removal capacities. Conversely, when the wax or the mixture of waxes has a melting point of less than 55 ° C, the content by weight of polymer or of mixture of polymers in the composition may be less than 20%, preferably less than 10%. . The nature of the wax (s), as well as the nature of the polymer (s), are of course also to be taken into consideration in order to give the composition the desired properties.

Advantageously, as thermoplastic polymer is used an ethylene-based copolymer, in particular an ethylene vinyl acetate copolymer, an ethylene octene copolymer, an ethylene butylene styrene copolymer, an ethylene propylene styrene copolymer, or a mixture thereof.

According to a preferred embodiment variant, the composition comprises a content by weight of paraffin wax with a melting point of less than 55 ° C which is greater than 90%, and a thermoplastic polymer chosen from copolymers of ethylene butylene styrene and ethylene propylene styrene copolymers or their mixture, the content by weight of the polymer or of the polymer mixture being less than 10%. More preferably, a mixture of ethylene butylene styrene copolymer and of ethylene propylene styrene copolymer is chosen.

In addition and advantageously, the composition of the invention can also comprise a fatty substance or a mixture of fatty substances, in particular to reduce the temperature of application of the mask and to make it compatible with contact of several minutes on the skin. avoiding the risk of burns.

For this purpose, one can for example use paraffin oil, lanolin or a lanolin substitute, mineral oil, vegetable oil, shea butter, Shorea butter, butter. olive, an oily complex of vegetable origin, a silica-based oil viscosity agent or a mixture thereof. In general, it is possible to use any fatty substance or any mixture of substances compatible with the wax or the mixture of waxes, and the polymer or the mixture of polymers.

The amount of fatty substance or mixture of fatty substances can vary between 2 and 50% by weight of the composition depending on the wax or the mixture of waxes used.

[0027] The composition of the invention may also contain cosmetic active ingredients, for example moisturizing and / or antioxidant.

The composition of the invention may also contain additives customary used in cosmetics such as preservatives, perfumes, softening agents, surfactants, colorants, without the additives altering the desired properties of the composition.

The composition of the invention is devoid of tackifying compound, in particular of tackifying resin or of any other compound which would increase the tackifying power by making it incompatible with removal by peeling from the face without the risk of hair pulling out.

The composition of the invention is used as a peel-off mask according to the following protocol: the mask (based on the composition of the invention) is heated to a temperature between 45 and 65 ° C. This temperature makes it possible to obtain a mask in liquid form, or at least of sufficient viscosity to ensure its spreading on the skin, by the combination of a wax or of a mixture of waxes of controlled melting point (s) ( s) and less than 70 ° C, but also the presence of one or more thermoplastic polymers, the nature and mass content of which are chosen accordingly. The mask is then spread over the face. The mask is left in place for several minutes, between 10 and 20 minutes, generally about 10 minutes, then removed by tearing. The occlusive nature of the mask and its temperature (as well as its relative thermal inertia) increase the diameter of the pores and contribute to the hydration of the skin as well as to the cleaning of the pores. Alternatively, when the composition does not contain active ingredients, a suitable composition comprising cosmetic active ingredients in the form of a cream or a gel can be applied to the skin prior to putting on the mask. If the composition comprises active agents or if a cream or a gel comprising active agents are applied beforehand to the skin, the occlusive nature of the wax-based mask further contributes to the increased penetration of these active agents. The penetration efficiency of the active agents is all the more important as the kinetics of cooling of the mask are low. Heat as such also brings comfort and relaxation to the user. Finally, the peelable nature of the mask ensures both easy removal in one piece, as well as a cleansing effect on the skin by removing dead cells. The mask of the invention thus ensures concomitantly as such a cleansing and hydration of the skin, and can also have the additional function of penetrating active agents into the skin. the hypothesis where active agents are integrated into the composition of the invention or applied beforehand to the skin.

[0031] According to the invention, specific conditions for the preparation of the composition have been developed, in particular in terms of the rate of casting of the mask and of the rate of cooling. This mainly involves avoiding any phenomenon of thermal shrinkage which is characterized by the appearance of a central cavity following the casting of a wax-based composition.

To do this, the mixture of wax (s) and polymer (s) is brought to a temperature between 110 and 170 ° C depending on the wax (s) used. It has been observed that two conditions must be observed in order to avoid the phenomenon of thermal shrinkage. First, the mixture is cooled before casting to a temperature between 80 and 90 ° C. In addition, the casting is carried out for a time greater than 2 hours per tonne of composition, preferably for a time greater than 3 hours, preferably 3 hours 30 minutes. These conditions make it possible to avoid too rapid crystallization of the wax and are reproducible for all the waxes and copolymers tested.

Examples of realization

Table 1 below sets out 8 examples of formulation of the composition of the invention as well as a composition outside the scope of the invention. For each composition, the mask is produced according to the method described above. More particularly, the heating temperature of the mixture of compositions A, B, C, D, H and I is 120 ° C, and the heating temperature of the mixture of compositions E, F and G is 160 ° C. Each mixture is cooled to a temperature between 80 and 90 ° C, and casting is carried out in 3 hours 30 minutes per tonne of composition.

Table 1: Compositions of the invention - PdF: Melting point

Table 2: Evaluation of the properties of the compositions used as a peelable mask for the face - unsatisfactory; + moderately satisfactory; ++ satisfactory; +++ very satisfactory

A panel of about fifteen consumers tested the masks made on the basis of compositions A to I and evaluated four criteria of the mask, namely its spread, its flexibility, its ease of removal and the diffusion of heat for a period of time. 10-minute exposure. The results are given in Table 2 below.

[0035] Composition A (counterexample) for which the melting point of the wax is of the order of 100 ° C, is considered unsatisfactory. In addition to the difficulty of spreading the composition on the skin without risk of burns directly linked to this high melting point, this composition is rigid, its cooling kinetics unsuitable for an exposure time of around ten minutes, and its difficult removal. .

For the other compositions B to I whose melting point of the wax or of the wax mixture is less than 100 ° C, one or more criteria can be judged "moderately satisfactory", which does not cause shrinkage of those compositions within the scope of the invention. In fact, all of the compositions B to I are capable of being used as a peel-off mask, some having more or less criteria. less positive but without ever being unsuitable for their use as a peel-off mask.

These results show more particularly that the masks respectively produced based on compositions E, F and G exhibit the most positive criteria. These three compositions are made from microcrystalline wax with a melting point of around 45-51 ° C ° C associated with an ethylene butylene styrene copolymer and / or an ethylene propylene styrene copolymer. Composition G comprising a mixture of ethylene butylene styrene copolymer and an ethylene propylene styrene copolymer exhibits the most optimal properties for the four criteria tested. These three compositions thus constitute the preferred compositions of the invention. It should be noted that tests were also carried out on these three compositions by adding to them a fatty substance of the paraffin oil and / or lanolin type, the results having been as conclusive as those presented in Table 2.

Claims

[Claim 1] Cosmetic composition for a peelable mask for cosmetic treatment of the skin, in particular of the face, characterized in that it comprises at least one wax or a mixture of waxes, and at least one thermoplastic polymer or a mixture of thermoplastic polymers .

[Claim 2] Composition according to Claim 1, characterized in that the wax or the mixture of waxes has a melting point below 80 ° C, preferably below 70 ° C.

[Claim 3] Composition according to Claim 2, characterized in that the wax or the mixture of waxes has a melting point greater than or equal to 55 ° C and in that the mass content of polymer or mixture of polymers in the composition is greater than or equal to 20%.

[Claim 4] Composition according to Claim 2, characterized in that the wax or the mixture of waxes has a melting point of less than 55 ° C and in that the mass content of polymer or mixture of polymers in the composition is lower. at 20%.

[Claim 5] Composition according to the preceding claim, characterized in that the content by mass of polymer or mixture of polymers in the composition is less than 10%.

[Claim 6] Composition according to any one of the preceding claims, characterized in that the wax is beeswax, microcrystalline wax, paraffin wax or a mixture of these waxes.

[Claim 7] Composition according to any one of the preceding claims, characterized in that the thermoplastic polymer is a copolymer of ethylene vinyl acetate, an ethylene octene copolymer, an ethylene butylene styrene copolymer, an ethylene propylene styrene copolymer, or a mixture of these copolymers.

[Claim 8] Composition according to any one of claims 4 and 5, characterized in that the wax is a paraffin wax, and in that the thermoplastic polymer is a copolymer of ethylene butylene styrene, a copolymer of ethylene propylene styrene or a mixture of these two copolymers.

[Claim 9] Composition according to Claim 8, characterized in that the thermoplastic polymer is a mixture of ethylene butylene styrene copolymer and of ethylene propylene styrene copolymer.

[Claim 10] Composition according to any one of the preceding claims, characterized in that it further comprises a fatty substance or a mixture of fatty substances of the oil or butter type.

[Claim 11] Composition according to any one of the preceding claims, characterized in that it constitutes a mask for cosmetic treatment of the skin, in particular of the face.

[Claim 12] Use of the composition according to any one of the preceding claims, as a peelable mask for cosmetic treatment of the skin, in particular of the face.

[Claim 13] Use according to the preceding claim, characterized in that it comprises at least the steps of:

- application of the mask to the skin, and

- removal of the mask by peeling after leaving the mask on the skin for a determined period of time.

[Claim 14] Process for producing a peelable mask for cosmetic treatment of the skin, in particular of the face, from the composition according to any one of claims 1 to 11, characterized in that it comprises at least the steps from:

- mixture of at least one, or a mixture of, wax (s), and at least one, or a mixture of, thermoplastic polymer (s)

- increasing the temperature of the mixture to a temperature between 110 and 200 ° C, preferably between 120 and 180 ° C, and obtaining a homogeneous mixture,

- decrease in the temperature of the mixture to a temperature between 70 and 90 ° C,

- casting of the mask for a period greater than or equal to 2 hours, and

- cooling to room temperature

[Claim 15] Method according to the preceding claim, characterized in that the wax of the composition is a paraffin wax, in that the thermoplastic polymer is an ethylene butylene styrene copolymer, an ethylene propylene styrene copolymer or a mixture of these two copolymers, in that the increase in the temperature of the mixture is carried out up to a temperature between 150 and 170 ° C, in that the decrease in temperature is carried out until a temperature of between 75 and 95 ° C, and in that the casting is carried out for a period greater than or equal to 3 hours.