Human skin exfoliation process

Abstract

Method for exfoliating human skin. A method for exfoliating skin, including the scalp, and / or nails, comprising the step of subjecting a surface of said skin (K), or said nails, to a cosmetic composition and to ultrasonic acoustic waves emitted by a device comprising at least one ultrasonic transducer (13), with an acoustic intensity Isata at the level of the region exposed to the acoustic waves of at least 0.1 W / cm², i) the transducer being moved relative to said surface at an average scanning speed of between 0.01 cm² / s and 15 cm² / s during the treatment time of said surface, and / or ii) the device being applied in one location on the keratinous materials, then removed from them and applied in a different location. Figure for the abstract: Fig. 1

Description

Title of the invention: Method for exfoliating human skin Technical field

[0001] The present invention relates to the treatment of human keratin materials, and more particularly the exfoliation of the skin, scalp, or nails. Prior art

[0002] Application EP 3 294 469 describes a device for cleaning a surface, comprising a chamber supplied with a liquid and communicating with an outlet conduit opening onto the surface to be cleaned, and an ultrasonic transducer transmitting acoustic energy to the liquid contained in the chamber and the outlet conduit.

[0003] Application ES 2 708 149 discloses a device for cleaning a surface comprising a sonotrode generating ultrasound near a cleaning solution present on the surface, the cavitation making it possible to remove dirt from the surface.

[0004] Patent US8486199 describes a device for treating a surface of a semiconductor wafer comprising a resonator for supplying ultrasonic energy to a treatment fluid containing gas bubbles.

[0005] Document EP 1 645 342 describes a method for cleaning equipment consisting of subjecting a liquid comprising bubbles to an acoustic field.

[0006] Patent KR101152920 describes a skin cleansing device comprising a vacuum pump and intended to be used in proximity to a liquid containing microbubbles on the skin.

[0007] Applications US 2017 0080257, KR 2020 0102956, US 2009 / 318853, JP 2016 214424 and WO 2020 / 029429 disclose methods for cosmetic treatment of the skin, in particular its cleansing, using an ultrasonic device which generates microbubbles in a cosmetic composition applied to the skin to be cleansed.

[0008] Similar devices are disclosed in applications US 2011 / 21328, US 2010 / 010420, EP 3 634 643, CN206995178, WO 2022 / 112361 and EP 2 470 310.

[0009] Today, skin exfoliation, i.e. the removal of dead skin, is mainly carried out by mechanical dermabrasion, in particular with brushes or rotating cutters with a rough surface, by chemical desquamation, better known as peeling, or by scrubbing.

[0010] However, these techniques have drawbacks and can lead to complications. Mechanical dermabrasion can lead to hyperpigmentation or hypopigmentation, persistent redness and / or pain, scars, or even microbial infections. During chemical peeling, the skin may itch. and redden, then scabs may appear. One of the main complications of chemical peels is deep burning of the skin, resulting in scarring, hyperpigmentation or hypopigmentation. Finally, exfoliating the skin can cause micro-lesions, unbalance the hydrolipidic film that protects the skin, or even dry out the skin. Furthermore, exfoliation is often inhomogeneous and made from compositions with many constituents.

[0011] There is therefore a need for skin exfoliation techniques that are more respectful of the skin, and of the individual by extension, and that do not cause scarring or undesirable changes in skin pigmentation. There is also a need to reduce the environmental impact of the products used for this exfoliation. Statement of the invention

[0012] The invention aims to propose a method for exfoliating human skin, in particular the skin of the face, scalp, or nails, allowing in particular the removal of dead skin cells. Summary of the invention

[0013] The invention thus relates, according to a first of its aspects, to a method for exfoliating the skin, including the scalp, and / or the nails, comprising the step of subjecting a surface of said skin, or of said nails, to a cosmetic composition and to ultrasonic acoustic waves emitted by a treatment device comprising at least one ultrasonic transducer, with an acoustic intensity Isata at the region exposed to the acoustic waves at least equal to 0.1 W / cm2, (i) the transducer being moved relative to said surface at an average scanning speed of between 0.01 cm2 / s and 15 cm2 / s during the treatment time of said surface, and / or ii) the device being applied to one location on the keratin materials, then moved away from them and applied to a different location.

[0014] The method of application of step ii) corresponds to what is called a “tapping” movement, where the device is applied to the keratin materials by a succession of movements of bringing said materials closer and further apart, shifting it each time. There may be a greater or lesser overlap of the treated area between two successive contacts; for example, between 10 and 90% of the area treated during one contact may be treated during the following contact.

[0015] The method of application of step i) can be carried out without loss of contact of the device with the keratin materials.

[0016] The method may comprise only the mode of application of step i). In alternatively, the method comprises only the mode of application of step ii).

[0017] It is also possible to have a hybrid operation, combining tapping and scanning in contact with said materials, that is to say that when the device comes into contact with said materials the device is moved into contact with them and phases of contact of the device with said materials are alternated with phases of shifting of the device without contact with said materials. The method can therefore comprise both the application mode of step i) and that of step ii).

[0018] In this way, it is possible to generate bubbles within the cosmetic composition in the vicinity of the surface to be treated and cause them to collapse, which is accompanied by a shock wave which contributes to the elimination of dead cells. The choice of acoustic intensity and speed ensures a good compromise between comfort of use and effectiveness of the treatment.

[0019] Preferably, the transducer is moved relative to said surface at an average scanning speed of between 5 cm2 / s and 15 cm2 / s, better still between 7 cm2 / s and 10 cm2 / s, during the treatment time of said surface.

[0020] This process is preferably cosmetic for non-therapeutic purposes. The process according to the invention is notably implemented for the exfoliation of keratin materials, notably of the skin, in order for example to obtain effects of re-smoothing of the skin, of cell renewal, of improving the homogeneity of the skin complexion and / or its radiance.

[0021] The term "cosmetic composition" means a composition containing at least one cosmetic active ingredient, as defined in the Cosmetics Directive 76 / 768 / EEC. According to the invention, mineral or tap water does not constitute a cosmetic composition.

[0022] Exfoliation can in particular be carried out on the superficial layers of the skin. The area of ​​skin which is exfoliated according to the invention can be the skin of the face, the bust, the back, the arms, the legs, the hands and / or the feet, the scalp, the nails. The method according to the invention is particularly suitable for exfoliating the skin of the face, in particular the forehead, the cheeks, the chin, the neck, the nose, the scalp.

[0023] The method according to the invention makes it possible to obtain results equivalent to, or even better than, mechanical dermabrasion, chemical peeling or even exfoliation, without the undesirable effects caused by these techniques.

[0024] Exfoliation corresponds in particular to a protein dosage of at least 0.4 micrograms in the dead cells removed from one cm2 of treated skin or nails, better still a dosage of at least 1 qm / cm2, even better still a dosage of at least 1.8 qm / cm2.

[0025] The method according to the invention may also be suitable for skin or nail care, or for cleaning and / or preparing the skin, scalp, or nails.

[0026] The method according to the invention makes it possible to effectively eliminate or treat endogenous impurities or defects.

[0027] Among the endogenous impurities or defects, we can note dead cells, dead skin, dandruff.

[0028] Acoustic waves make it possible to cause complete cavitation of bubbles within the composition in order to generate a mechanical effect on the surface to be treated.

[0029] By "complete cavitation" is meant here both the generation and the collapse of bubbles causing a mechanical shock on the surrounding surfaces. The cosmetic composition may, or may not, have bubbles already present within it before the application of the acoustic waves. The composition may also include a gas dissolved therein, for example carbon dioxide, nitrogen, oxygen, or any gas that can be solubilized in the composition.

[0030] The bubbles generated and / or present may also contribute to the release of chemical species contributing to the exfoliation of the skin or nails, such as free radicals.

[0031] The scanning speed corresponds to the area per unit time arriving in the area located below the surface of emission of the acoustic waves and not being there before. Cosmetic composition

[0032] Preferably, the cosmetic composition contains at least one surfactant, in particular with a total mass concentration of surfactant(s) in the composition of less than or equal to 1%.

[0033] The surfactant(s) contribute to the suspension of corneocytes by formation of micelles, and thus contribute to the elimination of dead cells.

[0034] The total level of surfactant(s) less than or equal to 1% by mass in the cosmetic composition makes it possible to reduce the ecological footprint of the cosmetic composition and to limit the undesirable effects of surfactants on the skin or nails, such as irritations and allergies.

[0035] The cosmetic composition preferably has a total mass concentration of surfactant(s) of between 0.01% and 20% by weight relative to the total mass of the composition, better still between 0.01% and 5%, even better still 0.1% and 1.5%, even better still between 0.1% and 1%.

[0036] The surfactants may contribute to the formation of bubbles and / or to their stabilization, being for example chosen from foaming surfactants such as polyoxyalkylenated alkyl(amido) ether carboxylic acid anionic surfactants, anionic surfactants other than the aforementioned polyoxyalkylenated alkyl(amido) ether carboxylic acids, non-ionic surfactants, amphoteric and zwitterionic surfactants, and mixtures thereof and / or are chosen from the compounds present clas exclusively within makeup remover compositions such as alkylpolysaccharides, polyethylene glycol fatty alcohols, oils, and their mixtures. Any surfactant capable of generating micelles in the medium can be used.

[0037] The cosmetic composition sent into contact with the surface to be treated can be at least partially recovered and / or recycled.

[0038] The cosmetic composition can be applied continuously, that is to say that a circulation of the composition is established in contact with the surface to be treated, this circulation being for example in a closed or open circuit.

[0039] The cosmetic composition may comprise at least one so-called “peeling” active ingredient chosen from acids, in particular fruit acids, strong acids, in particular hydrochloric acid, weak acids, in particular citric acid, acetic acid, keratolytic compounds, in particular salicylic acid. This active ingredient may be in a mass concentration of between 0.01% and 10% by mass, for example. Acoustic waves

[0040] The acoustic intensity Lata can be defined as the average acoustic power on the surface subjected to the acoustic waves, divided by said surface: I $ ata ~ Pmoy!S, the average acoustic power taking into account the duty cycle when the electrical signal supplying the transducer is pulsed.

[0041] The acoustic intensity Lata is preferably between 0.1 and 10 W / cm2, better between 1 and 5 W / cm2, even better 2.5 and 5 W / cm2, even better between 3 and 4 W / cm2

[0042] The energy delivered by the device on said surface is preferably between 0.1 J / cm2 and 15 J / cm2, better between 0.1 J / cm2 and 10 J / cm2, during exfoliation.

[0043] The acoustic waves can be generated by a single transducer, or alternatively by at least two transducers.

[0044] The only air bubbles present in the composition may be those generated by acoustic waves.

[0045] Each transducer comprises one or more electroactive elements for transforming an electric current into mechanical vibrations, this or these electroactive elements being for example based on piezoelectric materials, as detailed below.

[0046] This or these electroactive elements can be coupled to a sonotrode which can be mechanically resonated by the electroactive element(s) and serves to define a surface for emitting acoustic waves towards the target surface or volume.

[0047] The acoustic waves can be generated permanently as soon as the treatment device is put into operation, or alternatively only be generated when certain operating conditions are met, such as for example the presence of the composition in contact with the sonotrode and / or the presence of the device in contact with the area to be treated and / or if the device detects that the area contains sa- smoothness.

[0048] Alternatively, the acoustic waves can be generated only when the quantity of composition in contact with the surface to be treated is sufficient, or when certain conditions for generating cavitation are detected, such as contact between the emission surface of the sonotrode and the surface to be treated, a minimum height of composition, a temperature of composition or transducer within a given range, or other.

[0049] The surface area for emitting the acoustic waves ranges, for example, from the surface area of ​​a circle with a diameter of 5 mm to a circle with a diameter of 100 mm, better still from the surface area of ​​a circle with a diameter of 5 mm to that of a circle with a diameter of 50 mm, even better still from the surface area of ​​a circle with a diameter of 5 mm to that of a circle with a diameter of 40 mm, in particular the surface area for emitting the acoustic waves is substantially equal to the surface area of ​​a circle with a diameter of 12 mm.

[0050] They can be generated by a sinusoidal electrical signal or by a signal of more complex shape, for example frequency modulation or amplitude modulation. The acoustic waves are preferably emitted at a single frequency, which can allow them to be focused more precisely in a given area, but alternatively they can be emitted at several different frequencies.

[0051] Said frequency is preferably between 10 and 500 kHz, better between 30 and 100 kHz, in particular between 30 and 55 kHz. The acoustic waves are for example generated by a transducer with a nominal frequency of approximately 34 kHz.

[0052] The supply voltage of the transducer is preferably between 50 mVpp and 500 mVpp, this voltage is preferably amplified between 95 mVpp and 265 mVpp. The supply voltage of the transducer is for example between 130 mVpp and 160 mVpp, amplified between 248 mVpp and 331 mVpp. By "mVpp" is meant the peak-to-peak voltage of the signal in mV.

[0053] Said frequency associated with said supply voltage allows both the generation and satisfactory collapse of the bubbles in the composition, as well as a collapse alone of any bubbles already present in the medium in the composition.

[0054] The electrical signal exciting the transducer(s) may be pulsed with a pulse duration preferably between 0.01 s and 0.09 s, in particular equal to 0.03 s or 0.08 s.

[0055] The Ton / Toff duty cycle, when the signal is pulsed, is preferably between 10% and 90%, better still between 30% and 80%, even better still between 50% and 70%, for example approximately equal to 50%, Ton designating the duration during which the transducer is powered during a cycle and Toff the duration during which it is switched off.

[0056] The method may comprise a step of detecting the presence of the composition cosmetic in contact with the sonotrode, and condition the operation of the transducer to this detection.

[0057] This avoids the emission of acoustic waves in the absence of composition or when the device is not in a situation of treating the skin or nails.

[0058] Preferably, the acoustic waves are emitted without the emission surface of the sonotrode coming into contact with the area to be treated. The distance between the transducer and the surface to be treated is for example between 0.1 mm and 30 mm, more particularly between 3 and 5 mm, when the skin is exposed to the acoustic waves, which makes it possible to limit the acoustic energy emitted in the skin, and to promote the cavitation of the bubbles in the composition.

[0059] “The distance between the transducer and the surface to be treated” should be understood as the distance between the emission surface of the sonotrode and the surface to be treated.

[0060] A composition can be circulated continuously in contact with the sonotrode, with continuous operation of the transducer(s), or alternatively, pulsed operation of the transducer(s). The composition can also be supplied in a pulsed manner. Advantageously, a supply of a zone subjected to acoustic waves is discontinuous, for example with a period of supply of the zone while the acoustic waves are not generated, then a period where the composition present in the zone is subjected to the acoustic waves without being renewed during this exposure. This can prevent the bubbles present in the composition before entering said zone from being repelled by the acoustic waves present therein.

[0061] It is thus possible to control the supply of composition to the exfoliation zone to the operation of the transducer(s) for producing acoustic waves or vice versa, and to have a pulsed operation of the transducer(s) and / or the supply of composition. In other words, it is possible to carry out a supply of composition offset in time relative to the period of emission of the acoustic waves in the composition supply zone.

[0062] The propagation of acoustic waves is facilitated by the presence of liquid in the composition. The gas / liquid mass ratio within the composition can thus benefit from not being too high, and the composition can advantageously contain a thickener, or any other compound making it possible to increase the temporal stability of the bubbles. Abrasion

[0063] The method may include abrasion of the skin or nails using abrasive particles and / or by a part of the device in contact with the surface to be treated.

[0064] This abrasion can be carried out by a device other than the one which emits the waves. acoustic, by the device itself, or by a specific part mounted on the device, such as a grid, a blade, a scraper, granules stuck on the device, such as diamond or silica particles, or any other suitable accessory.

[0065] The part allowing the abrasion to be carried out is for example put in place to carry out the abrasion, then removed at the time of exfoliation by the bubbles and acoustic waves, being for example interchangeable with a part of the device used for exfoliation by the acoustic waves and bubbles.

[0066] The part allowing the abrasion to be carried out may still be present during the exfoliation of the bubbles and acoustic waves, as will be described below. This part may then have the form of a grid, among other possibilities.

[0067] The abrasion may be carried out prior to the exposure of the cosmetic composition and the bubbles to the acoustic waves, or alternatively concomitantly. When the abrasion is prior, it may be carried out by any means, in particular by mechanical or chemical action. Grid

[0068] The ultrasonic transducer preferably belongs to a device further comprising a grid defining a contact surface with said surface to be treated, the grid having at least one opening, preferably at least two openings, through which the waves emitted by the transducer can propagate in the direction of the surface to be treated.

[0069] The method according to the invention may comprise the step of exposing at least part of the surface of the skin or nails to acoustic waves while it is in contact with the grid.

[0070] Thanks to the grid, it is possible to control more precisely the distance between the transducer and the surface to be treated, which makes it possible to improve the action of the bubbles in the vicinity of said surface, while avoiding direct contact of the transducer with this surface.

[0071] The grid is preferably non-absorbent, i.e. it is not porous.

[0072] The grid may in particular not have the capacity to soak up water when immersed in water, and retain for example less than 10% of water, better still less than 5% of its water weight.

[0073] The grid can in particular be made from a solid material, therefore different from foam, fabric or felt.

[0074] The contact surface of the device with the skin or nails may be defined by a non-absorbent surface of the grid.

[0075] The region of the grid defining the openings thereof may be defined by a non-absorbent portion of the grid.

[0076] The grid is preferably removable, that is to say it can be easily detached by the user from the device, preferably without the use of tools. This makes it easier to clean and allows it to be replaced between uses, or, if desired, to interchange several grids depending on the use, for example by choosing the type of grid best suited to the morphology of the area to be treated.

[0077] The contact surface defined by the grid may be substantially flat, for example in order to maintain a substantially constant distance between the transducer and the surface to be treated located opposite the surface emitting the acoustic waves.

[0078] Alternatively, the grid may define a contact surface adapted to the morphology of the area to be treated, for example of a curved shape.

[0079] The grid may further have, where appropriate, an adjustable effective diameter. The device may comprise a variable aperture mechanical element such as a diaphragm, arranged in front of or behind the grid, so as to adjust the accessible diameter of the opening(s). For example, the device comprises a diaphragm centered on the longitudinal axis of the transducer.

[0080] Some or all of the openings of the grid can be closed in whole or in part in a controlled manner. This makes it possible, depending on the area to be treated, and in particular for more sensitive areas such as those located in the vicinity of the eyes, to limit the surface area and intensity of treatment, if desired. The device may comprise a shutter movable between a position of non-occultation of one or more openings of the grid and a occultation position where the opening(s) are occulted at least partially, or even totally. This shutter is for example adjusted manually by the user as required.

[0081] Preferably, the grid has a thickness of between 0.1 and 10 mm, better still between 0.5 and 5 mm. Thus, a minimum distance of at least this thickness is ensured between the transducer and the surface to be treated, regardless of the position of the grid relative to the transducer.

[0082] The grid is preferably formed from a rigid or semi-rigid material, for example metal, or rigid plastic. The grid is for example made from a material chosen from a metal, in particular steel, stainless steel, an alloy, silicone, a polymer, in particular of the polyurethane (PU), polyethylene terephthalate (PET) or polythiophene (PT) type, or a combination of several of these elements.

[0083] The grid may not deform visibly to the naked eye during normal use, due to its rigidity. Alternatively, the grid may be deformable. For example, its diameter may be reduced by applying mechanical pressure to its contour.

[0084] The grid may comprise recesses, in particular extending along its thickness. The grid comprises, for example, deformable channels, the diameter of which may vary according to the pressure applied, extending for example in a non-longitudinal direction. Alternatively, the channels may be rigid in order to allow the passage of fluid even if pressure is applied to the grid. The surface area of ​​the channels can be variable and their shape different, for example round, square, or triangular.

[0085] The grid may still have reliefs or be flocked, or not.

[0086] The grid can be made with reliefs or in an intrinsically rough, in order to have a non-smooth contact surface with the skin or nails. Such a surface condition allows for a mechanical abrasive effect that can contribute to exfoliation when the device is moved over the area to be treated during use. The grid may include several materials of varying abrasiveness, for example a more abrasive material in the center of the grid and a less abrasive material on the edges of the grid, or vice versa.

[0087] The device may comprise a gate drive element configured to generate an oscillating, vibrating and / or rotating movement of the grid to the skin. For example, the device comprises a motor for driving the grid into motion, for example rotary, linear, eccentric or other, reciprocating or not. The device may comprise a vibrator, if applicable, to vibrate the grid. The amplitude of the movement may be fixed or adjustable.

[0088] The mechanical abrasive effect can thus be obtained automatically due to the movement imposed by the device on the grid, and the impurities cleaned more efficiently.

[0089] The grid can be made in different ways.

[0090] The grid may comprise a peripheral frame, which defines the outer contour of the grid in front view. This frame may be rigid, in particular more rigid than a central part of the grid, openwork.

[0091] The outline of the grid, in front view, may be circular, oval, polygonal or other in shape, and preferably the grid has a closed outline.

[0092] The opening(s) of the grid may be substantially the same size. The grid may comprise a plurality of openings arranged in a regular pattern, for example in rows or columns.

[0093] Alternatively, the opening(s) may be arranged concentrically.

[0094] The openings may have various shapes, in particular shapes in the form of portions of disc(s) or ring(s).

[0095] The grid may have a single opening, in particular of non-circular outline, for example in the form of a slot, a cross, a polygon, regular or not, or an oval. Preferably, the grid has at least two openings, in particular two openings having substantially the same size.

[0096] In the presence of a single opening, this may or may not be centered.

[0097] A grid having a fine mesh improves the maintenance of the surface to be treated when using the device, which allows better control of a distance constant between the said surface to be treated and the surface of emission of the acoustic waves, and thus of the phenomenon of cavitation.

[0098] An opening of the grid may have an area of ​​at least 1 mm2. A smallest dimension of an opening of the grid, in front view, is for example at least 0.5 mm.

[0099] Preferably, the grid has a ratio of the total surface area of ​​the openings relative to the contact surface area of ​​the grid with the skin or nails greater than or equal to 0.3, better still 0.5, even better still 0.8.

[0100] Such a ratio makes it possible to prevent the skin or nails from rising up on contact with the transducer or from becoming deformed, while maintaining enough openings for the ultrasonic waves to reach the area to be treated or its vicinity over a sufficient extent with regard to the desired result.

[0101] Acoustic waves can propagate through at least one or two openings in the grid.

[0102] The grid may be moved during exfoliation, for example intermittently, remaining stationary for a certain period of time, then moved in increments, along the surface to be treated. The grid may still be moved continuously over the surface to be treated. Circulation of the composition in the grid

[0103] The device may further comprise at least one conduit extending into the grid.

[0104] Such a device makes it possible to apply the cosmetic composition continuously, that is to say that a circulation of the composition is established in contact with the surface to be treated, this circulation taking place for example in a closed or open circuit.

[0105] When the circulation is established in a closed circuit, the device may comprise at least one return conduit connected to a suction pump, making it possible to recover at least partially the composition in the vicinity of the surface to be treated, in particular at least one conduit extending into the grid. Method

[0106] The method according to the invention can be carried out on bare skin, on the scalp or on the nails.

[0107] The method may comprise one or more passes of the device, in particular vertically from top to bottom in the case of facial skin, over the surface of the skin during exfoliation.

[0108] The transducer may be moved in a translational and / or rotational motion relative to said surface during exfoliation.

[0109] The transducer may be mobile throughout the duration of the treatment, or if not, static relative to said surface for a duration not exceeding 0.5 s, better still 1 S.

[0110] The contact pressure of the device on the surface to be treated may be greater than or equal to 0.2 N / cm2 during exfoliation, this contact pressure being in particular the pressure of the grid on the surface to be treated, or that of another element of the device in contact with the surface to be treated, in particular a non-smooth or rough element. Related methods

[0111] The process according to the invention may be preceded or followed by another cosmetic process.

[0112] In one example, a surface of the skin is exfoliated by implementing the method according to the invention, then a treatment is carried out on the exfoliated area (for example just after or less than two hours after), for example a massage. Treatment kit

[0113] The invention also relates to a treatment kit for implementing the method according to the invention, as defined above.

[0114] This kit includes:

[0115] the cosmetic composition in which the bubbles are generated,

[0116] a device for exposing the cosmetic composition to acoustic waves in the vicinity of the surface to be treated.

[0117] The composition may or may not be packaged with the device in the same packaging.

[0118] Where appropriate, the composition is contained in a container arranged to be mounted on the device, this container constituting for example a cartridge arranged to be fixed in whole or in part in a corresponding housing of the device, or to be connected to the device by a suitable connection such as a pipe. Other compounds

[0119] The composition may generally comprise any compound conventionally included in the formulation of compositions for cleaning and / or caring for human skin, compatible with the generation of sufficiently stable bubbles during the application of acoustic waves. Brief description of the drawings

[0120] The invention may be better understood by reading the detailed description which follows, non-limiting examples of its implementation, and by examining the attached drawing, in which:

[0121] [Fig-1] illustrates schematically and partially, an example of a device of treatment of human skin implementing the method according to the invention,

[0122] [Fig.2] schematically and partially illustrates a handpiece of the device of [Fig.l],

[0123] [Fig.3] illustrates schematically and partially the device of [Fig.l] with a reservoir separate from the handpiece,

[0124] [Fig.4] illustrates schematically and partially the device of [Fig.l] in the form of a block diagram,

[0125] [Fig.5] partially and schematically represents a treatment head of the device of [Fig.l] comprising a grid,

[0126] [Fig.6A], [Fig.6B], [Fib 6C], [Fig.6D], [Fig.6E] and [Fig.6F] represent in a manner partial and schematic of the variants of realization of the grid of [Fig.5],

[0127] [Fig.7] illustrates the exfoliation performance of the skin under different conditions. Detailed description

[0128] Figures 1 to 4 illustrate a treatment device 1 for exfoliating the skin K, arranged to implement the method according to the invention, comprising a handpiece 2 and a support 3. Handpiece

[0129] The handpiece 2 comprises a handle 4, a treatment head 5, a circuit 6 for the circulation of a composition C and at least one reservoir 7 containing this composition C.

[0130] The reservoir 7 makes it possible, during operation of the device, to compensate for any losses in composition, in the event of non-recycling of part of it.

[0131] The reservoir 7 is preferably separable from the handpiece, as illustrated in [Fig. 3]. Alternatively, the reservoir 7 is not separable from the handpiece.

[0132] The reservoir preferably comprises a wall 15 which is at least partly transparent, allowing a user to determine the level of cosmetic composition present in the reservoir 7.

[0133] The circuit 6 comprises a delivery pump 11, shown schematically in [Fig.4]. The pump 11 can be driven by any type, in particular manually or electrically, preferably electrically. It can be of various types. The pump 11 is for example a volumetric or centrifugal pump, in particular peristaltic, diaphragm, piston, or a combination of several types. The pump 11 can be powered by direct or alternating current. Preferably, the supply voltage of the pump 11 is less than 50V, being for example powered by a voltage ranging from 5 to 12V. The pump 11 is preferably compatible with liquids of various types, in particular aqueous, oily, mixed liquids, liquids containing particles or suspended charges, or even polymers. The drive of the mechanism of the pump 11 can be done directly by a motor or in a reduced manner.When the drive is manual, the device 1 may comprise a handle which is operated by the user to operate the pump 11. Of . Preferably, the pump 11 is configured to provide a fluid flow rate between 0.01 mL and 15 mL per second. The pump 11 may be removable, or not. The pump 11 may generate negative and / or positive pressure on the fluid to allow the circulation of the fluid and its contact with the skin. The pump may also be used for internal cleaning of all or part of the device. The pump 11 may contain a filter in one or more parts. The pump 11 may be mechanically or electrically isolated in the device 1, for example to be removed from the device 1 for cleaning.

[0134] The treatment head 5 comprises a surface 10 in contact with the composition C, the treatment head 5 being arranged to deliver the composition C to an area of ​​the skin K to be treated.

[0135] The treatment head 5 comprises at least one transducer 13 emitting acoustic waves and a sonotrode, the surface 10 in contact with the composition being for example defined by a free end of the sonotrode. Bubbles can be generated in the composition C thanks to the acoustic waves due to the power and frequency of the acoustic waves.

[0136] The transducer 13 may be powered by an electrical source with direct or alternating current. The acoustic power delivered by the transducer 13 may vary depending on the supply voltage of the transducer and / or depending on the current supplying the transducer, in particular depending on its direct or alternating state.

[0137] The emission surface 10 of the acoustic waves towards the liquid medium may comprise reliefs or engravings where the bubbles can originate at different levels along the longitudinal axis of the transducer 13. In particular, these reliefs may offer nucleation sites at their top and at their base. The reliefs may allow a more homogeneous production of the bubbles. These reliefs may also promote the collapse of the bubbles, because the differences in levels along the longitudinal axis make it possible to generate relatively extensive cavitation zones, not limited to a single plane. In addition to the reliefs of the emission surface 10 which contribute to improving the production of the bubbles, the emission surface may have reliefs which pursue another purpose, for example exercising an action of retaining the fluid or cleaning the zone to be treated.These are, for example, reliefs made of a flexible material, for example hairs, in particular flocking hairs.

[0138] The handpiece 2 comprises an electronic circuit 14 comprising in particular a control unit 19.

[0139] The control unit 19 controls the operation of the pump 11, of a battery 18 supplying the device (in particular its load), of the transducer 13.

[0140] The control unit 19 is connected by a connector to an electronic generator 16, supplying in particular the transducer 13. This generator 16 comprises for example an oscillator and a power stage.

[0141] The battery 18 may be removable, it may be used to power the entire device 1, or only a part, in particular the pump 11. The battery 18 may be of various types, for example Li-ion or NiMH, preferably of a type suitable for humid conditions or which can be immersed in a liquid at least partially. The battery 18 is preferably rechargeable. The battery 18 is preferably selected to ensure, without having to be recharged, the power supply of the device 1 during several consecutive exfoliations, or even several exfoliations and cleaning of the device 1.

[0142] The handpiece 2 may comprise a grid 20 in contact with the skin to be treated, comprising for example regular openings arranged in rows and columns, as shown in [Fig.5].

[0143] The grid 20 can be produced in different ways.

[0144] The grid 20 comprises at least one opening 300; it may comprise exactly one opening, as illustrated in [Fig.6F], or exactly two openings, as illustrated in [Fig.6A], or more.

[0145] The openings may be mostly, or all, of similar size, as shown in [Fig.6B], [Fig.6D] or [Fig.6E]. They may be of various shapes, for example square, round, or a portion of a disc or ring, as shown in [Fig.6C],

[0146] The grid 20 preferably has a ratio of the total surface area of ​​the openings relative to the surface area of ​​contact with the skin greater than or equal to 0.5, which makes it possible to benefit from openings that are wide enough to allow the shock wave generated by the collapse of the bubbles to reach the skin K over a suitable surface area.

[0147] The grid 20 may be of circular outline, as illustrated in FIGS. 6A to 6F or of another shape, for example polygonal.

[0148] The external face of the grid 20 may be flat, and oriented for example parallel to the surface 10.

[0149] The grid 20 may be a single piece, formed by machining or injection molding for example.

[0150] Its thickness can be chosen so as to give it the desired rigidity.

[0151] The grid 20 can be made of metal, with a surface condition, on its face coming to skin contact, smooth or rough. The grid 20 is for example made of aluminum or aluminum alloy, or stainless steel. The grid 20 can also be made of a rigid plastic material, or ceramic. The grid 20 can also be composite, and include for example a frame embedded in a plastic matrix.

[0152] The grid 20 may be made of a deformable and / or compressible material. The grid 20 may thus be compressed during its use to a thickness ensuring a minimum distance between the emission surface and the surface of the skin to be treated.

[0153] A smooth surface condition of the grid 20 can facilitate movement on the skin in particular, while a rough surface condition can exert a mechanical action contributing to the exfoliation of the skin.

[0154] Each opening of the grid 20 may be delimited by a sharp edge, on the face of application to the skin. Such a sharp edge may promote exfoliation, by scraping the skin during the movement of the grid in contact with them.

[0155] Conduits for supplying and returning the cosmetic composition may extend into the grid 20. Support

[0156] The support 3 comprises, as illustrated in [Fig. 3], a first housing 8 for receiving the handpiece 2 and a second housing 9 for receiving the reservoir with an opening of the reservoir 7 facing downwards. The reservoir 7 can be received in the housing 9 of the support, while the handpiece 2 separated from the reservoir 7 is received in the housing 8 of the support 3.

[0157] The support 3 can accommodate other accessories necessary for the operation or recharging of the device. The support 3 can in particular accommodate accessories, such as a brush, a key, a screwdriver, necessary for the disassembly and / or cleaning of internal or removable parts of the device.

[0158] The device is for example charged using a USB port (not shown), in particular arranged on the support 3. The support 3 comprises for example, as illustrated, a first connector 32 and the handpiece 2 a second connector 22 arranged to connect to the first connector 32 when the handpiece 2 is received on the support 3, this connection allowing the handpiece 2 to be charged. The connectors 22 and 32 may be connectors of which at least one is spring-loaded.

[0159] Alternatively, the handpiece 2 can be charged by induction when it is received on the support 3.

[0160] The battery 18 can also be removed and charged separately. Skin exfoliation process K

[0161] The device 1 can be used for exfoliation of the skin K.

[0162] The treatment head 5 is thus brought close to the skin K by the user manipulating the handpiece 2, and the latter can start the device 1 while the treatment head is applied against the skin K.

[0163] Preferably, the acoustic waves are emitted without the emitting surface of the sonotrode does not come into contact with the area to be treated. The grid 20 makes it possible to maintain a minimum distance between the surface 10 emitting the acoustic waves and the surface of the skin K to be treated. The distance between the surface 10 and the surface to be treated is for example between 3 mm and 5 mm, in particular equal to 3 mm.

[0164] Composition C from reservoir 7 then circulates in circuit 6 by driving pump 11. Composition C is released upon contact with the skin.

[0165] Cosmetic composition C preferably comprises a mass concentration of surfactants less than or equal to 1%.

[0166] The transducer 13 generates acoustic waves allowing the formation of bubbles within the cosmetic composition C, and their collapse, thus allowing the desired exfoliation of the skin.

[0167] The frequency of the acoustic waves is preferably between 30 kHz and 45 kHz. Such a frequency allows both the generation and satisfactory collapse of the bubbles in composition C, as well as a collapse alone of any bubbles already present in the medium in the composition.

[0168] The electrical signal exciting the transducer 13 may be pulsed with a pulse duration preferably between 0.01 s and 0.09 s, in particular equal to 0.03 s or 0.08 s. The duty cycle, when the signal is pulsed, is preferably between 30% and 80%, in particular equal to 50%.

[0169] The acoustic intensity Lata of the acoustic waves on the surface of the skin K to be treated is preferably between 0.3 W / cm2 and 10 W / cm2, better between 3 W / cm2 and 4 W / cm2, in particular equal to 3.18 W / cm2 or 3.50 W / cm2.

[0170] The control unit 19 may only start the pump 11 and the emission of acoustic waves when the area to be treated is in contact with the grid 20, in particular in a manner which allows the composition to be recycled.

[0171] Composition C is reinjected, at least in part, into circuit 6, in particular using a suction pump 30. Composition C then enters treatment head 5 to be sent to a treatment and purification unit 40.

[0172] At the outlet of the treatment and purification unit 40, the composition C is returned to the tank 7.

[0173] During use of the device 1, the handpiece is moved by the user in a translational and / or rotational movement relative to the surface of the skin K to be treated.

[0174] During use of the device 1, the user preferably manipulates the handpiece 2, so that a skin surface of 5.309 mm2 is exfoliated for a duration of between 1 s and 60 s, better for a duration of between 7 s and 20 s.

[0175] The surface 10 is preferably moved relative to the skin at an average scanning speed of between 7 cm2 / s and 9.9 cm2 / s during the treatment period. Comparative examples

[0176] [Fig.7] illustrates the performance of different exfoliation techniques. The graph represents the amount of protein released by corneocytes removed from the skin under different conditions.

[0177] The different exfoliation conditions, tested on similar skin samples, are as follows: - Cl (outside the invention): a transparent adhesive disc is stuck and held on the surface of the skin for 5 s with a weight of 2 kg then peeled off, it then removes all the corneocytes, - C2 (outside the invention): 100 mg of a commercially available skin scrub solution is applied by rotating the finger for 7 s on the skin; - C3 (outside the invention): 0.5 mL of a peeling solution containing 30% glycolic acid is applied by rotating the finger for 7 s on the skin, then left on for 20 min; - C4 (example according to the invention): a quantity of 1.5 mL of a cosmetic composition comprising 1% surfactants is applied to the skin in combination with ultrasonic waves emitted by the skin treatment device 1 without grid 20, described above, for approximately 7 s, making 5 revolutions on the skin sample, with a scanning speed of approximately 7 cm2 / s; - C5 (example according to the invention): 1.5 mL of the cosmetic composition is applied to the skin in combination with ultrasonic waves emitted by the skin treatment device 1 without grid 20, described above, for 30 s, making approximately 20 revolutions on the skin sample, with a scanning speed of approximately 10 cm2 / s; - C6 (outside the invention): a quantity of 1.5 mL of the peeling solution is applied to the skin in combination with ultrasonic waves emitted by the skin treatment device 1 without grid 20, described above, for approximately 7 s, making 5 revolutions on the skin sample, with a scanning speed of approximately 7 cm2 / s; - C7 (example according to the invention): a quantity of 1.5 mL of the cosmetic composition is applied to the skin in combination with ultrasonic waves emitted by the skin treatment device 1 with grid 20, described above, for approximately 7 s, making 5 revolutions on the skin sample, with a scanning speed of approximately 7 cm2 / s; - C8 (example according to the invention): a quantity of 1.5 mL of the cosmetic composition is applied to the skin in combination with ultrasonic waves. trasonic waves emitted by the skin treatment device 1 with grid 20, described above, for 30 s, making approximately 20 revolutions on the skin sample, with a scanning speed of approximately 10 cm2 / s; - C9 (outside the invention): a quantity of 1.5 mL of the peeling solution is applied to the skin in combination with ultrasonic waves emitted by the skin treatment device 1 with grid 20, described above, for approximately 7 s, making 5 revolutions on the skin sample, with a scanning speed of approximately 7 cm2 / s; - CIO (outside the invention): 0.25 mL of the cosmetic composition is applied to the skin in combination with a commercial electric cleansing brush, making 5 turns on the skin sample; - Eyelash (outside the invention): 0.5 mL of the peeling solution is applied to the skin in combination with the cleansing brush, making 5 turns on the skin sample; - C12 (outside the invention): 0.25 mL of a gel suitable for the cleansing brush is applied to the skin in combination with the brush, making 5 turns on the skin sample.

[0178] As can be seen in [Fig.7], the results obtained with the scrubbing solution (C2) are on average slightly better than those obtained with the ultrasounds associated with the grid and the cosmetic composition (C7 and C8). Without the grid 20, the results obtained with the ultrasounds are a little less good but equivalent to those obtained with the brush associated with its gel.

[0179] The peeling solution alone (C3) is more effective than when used with ultrasound (C6 and C9) or brush (C12).

[0180] The brush must be used with its gel containing a high level of surfactants (9%), to allow effective cleaning. Associated with the cosmetic composition and the peeling solution (CIO and C12), the brush is the least effective technology.

[0181] Finally, for the method according to the invention, it is noted that: - the use of the grid improves the removal of comeocytes (C7 > C4; C8 > C5 and C9 > C6); - with or without grid, a longer exfoliation time (30s) gives better results (C5 > C4 and C8 > C7).

[0182] The peeling solution with 30% glycolic acid has little effect on the stratum corneum, whether used alone or in combination with ultrasound.

[0183] The use of ultrasound with the grid for 30 seconds, associated with the cosmetic composition, gives results equivalent to those obtained with a commercial exfoliating solution (mechanical exfoliation). The use of ultrasound with the grid associated with the cosmetic composition gives better results than those obtained with the brush combined with its gel (9% surfactants) with 9 times less surfactants.

[0184] The ultrasounds associated with the grid improve the performance of the products (even with a low concentration of surfactant) thanks to a synergy of the ultrasonic and mechanical actions.

[0185] Of course, the invention is not limited to the examples which have just been described.

[0186] The handpiece may have only one pump which ensures the circulation of the fluid in the exfoliation zone, and its return to a reservoir intended to recover the used fluid.

Claims

Claims

1. Cosmetic process for non-therapeutic exfoliation of the skin, including the scalp, and / or the nails, comprising the step of subjecting a surface of said skin (K), or of said nails, to a cosmetic composition (C) and to ultrasonic acoustic waves emitted by a device (1) comprising at least one ultrasonic transducer (13), with an acoustic intensity Isata at the region exposed to the acoustic waves at least equal to 0.1 W / cm2, i) the transducer (13) being moved relative to said surface (K) at an average scanning speed of between 0.01 cm2 / s and 15 cm2 / s during the treatment time of said surface, and / or ii) the device (1) being applied to one location on the keratin materials (K), then moved away from them and applied to a different location.

2. Method according to claim 1, the energy delivered by the device (1) on said surface (K) being between 0.1 J / cm2 and 15 J / cm2.

3. Method according to one of claims 1 and 2, the cosmetic composition (C) containing at least one surfactant with a total mass concentration of surfactant(s) in the composition less than or equal to 1%.

4. Method according to one of claims 1 and 2, the cosmetic composition (C) containing at least one surfactant, the mass concentration of surfactant(s) being between 0.1% and 1.5%.

5. Method according to any one of the preceding claims, the composition (C) comprising at least one surfactant chosen from foaming surfactants such as polyoxyalkylenated alkyl(amido) ether carboxylic acid anionic surfactants, anionic surfactants other than the aforementioned polyoxyalkylenated alkyl(amido) ether carboxylic acids, non-ionic surfactants, amphoteric and zwitterionic surfactants, and mixtures thereof, and / or chosen from compounds conventionally present in makeup remover compositions such as alkylpolysaccharides, polyethylene glycol of fatty alcohols, oils, and mixtures thereof.

6. A method according to any preceding claim, being carried out on bare skin (K).

7. Method according to any one of the preceding claims, the device (1) emitting the ultrasonic acoustic waves comprising a grid (20) defining a contact surface with the skin (K) to be treated, the grid (20) having at least one opening (300) through which the waves emitted by the transducer (13) can propagate towards the skin (K) to be treated, the method comprising the step of exposing said surface (K) to the acoustic waves while it is at least partly in contact with the grid (20).

8. Method according to the preceding claim, the grid (20) having a ratio of the total surface area of the openings (300) relative to the contact surface area greater than or equal to 0.3, better still 0.

8.

9. Method according to any one of the preceding claims, comprising one or more passes of the device (1), in particular vertically from top to bottom in the case of facial skin, over said surface (K) during exfoliation.

10. Method according to any one of the preceding claims, the transducer (13) being moved in a translational and / or rotational movement relative to said surface (K) during exfoliation.

11. Method according to any one of the preceding claims, the transducer (13) being movable throughout the duration of the treatment or in the static negative relative to said surface (K) for a duration not exceeding 0.5 s, better still 1 s.

12. Method according to any one of the preceding claims, the contact pressure of the device (1) on the skin (K) being greater than or equal to 0.2 N / cm2 during exfoliation, this contact pressure being in particular the pressure of the grid (20) on the skin (K), or that of another element of the device (1) in contact with the skin (K), in particular a non-smooth or rough element.

13. A method according to any one of the preceding claims, the only air bubbles present in composition (C) being those generated by acoustic waves.

14. Method according to any one of the preceding claims, the cosmetic composition (C) being applied continuously to said surface (K) during exfoliation.

15. Method according to any one of the preceding claims, the cosmetic composition (C) sent into contact with the skin (K) during exfoliation being at least partially recovered and / or recycled.

16. A method according to any preceding claim, the acoustic waves having at least one frequency component between 30 kHz and 55 kHz.

17. Method according to any one of the claims, the electrical supply of the transducer (13) being pulsed, the duty cycle Ton / Toff being between 10% and 90%, and / or the pulse duration Ton being between 0.01 s and 0.09 s, Ton designating the duration during which the transducer (13) is powered during a cycle and Toff the duration during which it is switched off.

18. Method according to any one of the preceding claims, the distance between the emission surface (10) of the acoustic waves of the transducer (13) and the surface of the skin (K) to be treated being between 0.1 mm and 30 mm when the skin (K) is exposed to the acoustic waves.

19. A method according to any preceding claim, the scanning speed being between 5 and 15 cm2 / s.

20. Method according to any one of the preceding claims, T exfoliation corresponding to a protein dosage of at least 0.4 micrograms in the dead skin removed per cm2 of treated skin.

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