Process for exfoliating human skin

Abstract

A process for exfoliating the skin, including the scalp, and / or the nails, comprising the step consisting in 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 in the region exposed to the acoustic waves that is at least equal to 0.1 W / cm2, i) the transducer being moved relative to said surface at an average sweeping speed of between 0.01 cm2 / s and 15 cm2 / s for the duration of treatment of said surface, and / or ii) the device being applied to a location on the keratin material, then moved away from the latter and applied to a different location.

Description

[0001] Description

[0002] Title: Process for exfoliating human skin

[0003] Technical field

[0004] The present invention relates to the treatment of human keratin material, and more particularly the exfoliation of the skin, the scalp or the nails.

[0005] Prior art

[0006] Patent application EP 3 294 469 describes a device for cleaning a surface, including a chamber fed with a liquid and in communication with an outlet pipe emerging onto the surface to be cleaned, and an ultrasonic transducer transmitting acoustic energy to the liquid contained in the chamber and the outlet pipe.

[0007] Patent application ES 2 708 149 discloses a device for cleaning a surface comprising a sonotrode that generates ultrasound in close proximity to a cleaning solution present on the surface, the cavitation enabling dirt to be removed from the surface.

[0008] Patent US8486199 describes a device for treating a surface of a semiconductor wafer comprising a resonator allowing ultrasound energy to be supplied to a treatment fluid containing bubbles of gas.

[0009] Document EP 1 645 342 describes a method for cleaning equipment which consists in subjecting a bubble-containing liquid to an acoustic field.

[0010] Patent KR101152920 describes a device for cleansing the skin comprising a vacuum pump and intended to be used in close proximity to a microbubble-containing liquid on the skin.

[0011] Patent applications US 2017 / 0080257, KR 2020 / 0102956, US 2009 / 318853, JP 2016 / 214424 and WO 2020 / 029429 disclose processes for cosmetic treatment of the skin, notably for cleansing it, using an ultrasonic device which generates microbubbles in a cosmetic composition applied to the skin to be cleansed.

[0012] Similar devices are disclosed in patent applications US 2011 / 21328, US 2010 / 010420 and EP 3 634 643, CN206995178, WO 2022 / 112361 and EP 2 470 310.

[0013] Currently, the exfoliation of the skin, that is the removal of dead skin cells, is mainly carried out by mechanical dermabrasion, in particular using rotary brushes or burrs with a rough surface, by chemical desquamation, better known as peeling, or by scrubbing.

[0014] However, these techniques have drawbacks and can lead to complications. Mechanical dermabrasion can in particular lead to hyperpigmentation or hypopigmentation, persistent pain and / or redness, scarring, or microbial infections. Upon chemical peeling, the skin may become red and itchy, and scabs may then form. One of the main complications with chemical peeling is deep burns in the skin, leading to scarring, hyperpigmentation or hypopigmentation. Lastly, scrubbing the skin can give rise to microlesions, unbalance the hydrolipidic film protecting the skin, or dry out the skin. Moreover, scrubbing is often uneven and carried out using compositions containing many components.

[0015] There is therefore a need for skin exfoliation techniques that are kinder to the skin, and thus to the individual, and that do not give rise to scarring or undesirable changes to the pigmentation of the skin. There is also a need to reduce the environmental impact of the products used for such exfoliation.

[0016] There is also a need to improve the effectiveness of treatment using a cosmetic product applied to the keratin material, for example to make it possible, with unchanged effectiveness, to reduce the amount of active agent while facilitating its action, or for the same amount, increase its action.

[0017] Disclosure of the invention

[0018] The invention aims to propose a process for exfoliating human skin, in particular the skin of the face, the scalp or the nails, making it possible in particular to remove dead skin cells.

[0019] Summary of the invention

[0020] Thus, according to one of its aspects, the invention relates to a process for exfoliating the skin, including the scalp, and / or the nails, comprising the step consisting in subjecting a surface of said skin, or 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 in the region exposed to the acoustic waves that is at least equal to 0.1 W / cm2, i) the transducer being moved relative to said surface at an average sweeping speed of between 0.01 cm2 / s and 15 cm2 / s for the duration of treatment of said surface, and / or ii) the device being applied to a location on the keratin material, then moved away from the latter and applied to a different location.

[0021] The method of application of step ii) corresponds to what is referred to as moving by “tapping”, wherein the device is applied to the keratin material via a succession of movements toward and away from said material while shifting its position each time. Coverage of the area treated may be achieved to a greater or lesser extent between two successive contacts; for example, between 10 and 90% of the area treated during a contact may be treated during the next contact.

[0022] The method of application of step i) may be carried out without the device losing contact with the keratin material.

[0023] The process may comprise only the method of application of step i). Alternatively, the process comprises only the method of application of step ii).

[0024] There may also be hybrid operation, with a mixture of tapping and a sweeping action in contact with said material, in other words while the device is in contact with said material the device is moved around in contact with the latter and phases of contact between the device and said material are alternated with phases of shifting the device without contact with said material. The process may therefore comprise both the method of application of step i) and the method of application of step ii).

[0025] It is thus possible to generate, within the cosmetic composition, bubbles near the surface to be treated and cause these bubbles to burst, in conjunction with a shock wave which helps to remove dead cells. The acoustic intensity and the speed selected ensure a good compromise between ease of use and effectiveness of the treatment.

[0026] Preferably, the transducer is moved relative to said surface at an average sweeping speed of between 5 cm2 / s and 15 cm2 / s, better still between 7 cm2 / s and 10 cm2 / s, for the duration of treatment of said surface.

[0027] This process is preferably cosmetic, and non-therapeutic. The process according to the invention is implemented in particular for exfoliating keratin material, in particular the skin, for example in order to obtain skin smoothing effects, cell rejuvenation, or a more even and / or more radiant complexion.

[0028] The method according to the invention is implemented in particular as a cosmetic and non-therapeutic process in order to enhance the effects of any type of treatment for improving the surface of keratin material as well as the biology thereof. The term “cosmetic composition” denotes a composition containing at least one cosmetic active agent, as defined in the Cosmetics Directive 76 / 768 / EEC. According to the invention, mineral water or running water does not constitute a cosmetic composition.

[0029] The surface layers of the skin may be exfoliated in particular. The area of skin that is exfoliated according to the invention may be the skin of the face, neckline, back, arms, legs, hands and / or feet, and the scalp or the nails. The process according to the invention is most particularly suitable for exfoliating facial skin, notably of the forehead, cheeks, chin, neck, nose and scalp.

[0030] The process according to the invention makes it possible to obtain results that are equivalent to, or even better than, mechanical dermabrasion, chemical peeling or scrubbing, without the unwanted effects caused by these techniques.

[0031] The exfoliation corresponds in particular to a dose of proteins of at least 0.4 micrograms in the dead cells removed from one cm2of skin or nails treated, better still a dose of at least 1 pm / cm2, even better still a dose of at least 1.8 pm / cm2.

[0032] The process according to the invention may also be used for caring for the skin or the nails, or for cleansing and / or preparing the skin, the scalp or the nails.

[0033] The process according to the invention makes it possible to efficiently remove or treat endogenous impurities or defects.

[0034] Endogenous impurities or defects may include dead cells, dead skin or dandruff.

[0035] The 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.

[0036] “Complete cavitation” in this case means both generating and bursting bubbles, giving rise to a mechanical impact on neighbouring surfaces. The cosmetic composition may or may not have bubbles already present within it before the acoustic waves are applied. The composition may also have a gas dissolved in it, for example carbon dioxide, dinitrogen, dioxygen, or any gas that can dissolve in the composition.

[0037] The bubbles generated and / or present may also contribute toward the release of chemical species which contribute toward the exfoliation of the skin or the nails, such as free radicals.

[0038] The speed of sweeping corresponds to the extent of surface area per unit time which enters the area located under the acoustic wave emission surface and which was not therein before. Cosmetic composition

[0039] Preferably, the cosmetic composition contains at least one surfactant, in particular with a total concentration by mass of surfactant(s) in the composition of less than or equal to 1%.

[0040] The surfactant(s) contribute toward the suspension of comeocytes by forming micelles, and thus contribute toward the removal of dead cells.

[0041] The total content of surfactant(s) of 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 the nails, such as irritation and allergies.

[0042] The cosmetic composition preferably has a total concentration by mass of surfactant(s) of between 0.01% and 20% by weight with respect 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%.

[0043] The surfactants may contribute toward the formation of the bubbles and / or toward their stabilization, these surfactants being chosen, for example, from foaming surfactants such as polyoxyalkylenated alkyl(amido) ether carboxylic acid anionic surfactants, anionic surfactants different from the abovementioned polyoxyalkylenated alkyl(amido) ether carboxylic acids, nonionic surfactants, amphoteric and zwitterionic surfactants, and mixtures thereof, and / or are chosen from the compounds conventionally present in makeup-removing compositions such as alkylpolysaccharides, fatty alcohol polyethylene glycols, oils, and mixtures thereof. Any surfactant that can generate micelles in the medium may be used.

[0044] The cosmetic composition placed in contact with the surface to be treated may be at least partially recovered and / or recycled.

[0045] The cosmetic composition may be applied continuously, i.e. 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.

[0046] The cosmetic composition may comprise at least one active agent referred to as a peeling agent, selected from among 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 agent may be in a concentration by mass of between 0.01% and 10% by mass, for example.

[0047] Acoustic waves

[0048] The acoustic intensity Isata may be defined as the average acoustic power on the surface subjected to the acoustic waves, divided by said surface: ISATA=Pave. / S the average acoustic power taking into account the cyclic ratio when the electrical supply signal of the transducer is pulsed.

[0049] The acoustic intensity Isata is preferably between 0.1 and 10 W / cm2, better still between 1 and 5 W / cm2, even better still 2.5 and 5 W / cm2, even better still between 3 and 4 W / cm2.

[0050] The energy delivered by the device onto said surface is preferably between 0.1 J / cm2and 15 J / cm2, better still between 0.1 J / cm2and 10 J / cm2, during exfoliation.

[0051] The acoustic waves may be generated by a single transducer or, as a variant, by at least two transducers.

[0052] The only bubbles of air present in the composition may be those generated by the acoustic waves.

[0053] Each transducer comprises one or more electroactive elements for converting an electric current into mechanical vibration, this or these electroactive elements being for example based on piezoelectric materials, as described in detail below.

[0054] This or these electroactive elements may be coupled to a sonotrode that may be set in mechanical resonance by the electroactive element or elements and serves to define a surface for emission of the acoustic waves toward the target surface or volume.

[0055] The acoustic waves may be generated permanently as soon as the treatment device is switched on or, as a variant, may be generated only when certain operating conditions are met, for instance 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 there is dirt in the area.

[0056] As a variant, the acoustic waves may be generated only when the amount 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 sonotrode emission surface and the surface to be treated, a minimum composition height, a composition or transducer temperature lying in a given range, or the like.

[0057] The surface area for emission of the acoustic waves ranges for example from the surface area of a circle 5 mm in diameter to a circle 100 mm in diameter, better still from the surface area of a circle 5 mm in diameter to the surface area of a circle of 50 mm, even better from the surface area of a circle 5 mm in diameter to the surface area of a circle of 40 mm, in particular the surface area for emission of the acoustic waves is substantially equal to the surface area of a circle 12 mm in diameter.

[0058] They may be generated by a sinusoidal electrical signal or by a signal of more complex shape, for example with frequency modulation or with amplitude modulation. The acoustic waves are preferably emitted at a single frequency, which may enable them to be focused more precisely on a given area, but, as a variant, may be emitted at several different frequencies.

[0059] Said frequency is preferably between 10 and 500 kHz, better still 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 around 34 kHz.

[0060] The transducer supply voltage is preferably between 50 mVpp and 500 mVpp, this voltage is preferably amplified between 95 mVpp and 265 mVpp. The transducer supply voltage is for example between 130 mVpp and 160 mVpp, amplified between 248 mVpp and 331 mVpp. “mVpp” means the peak-to-peak voltage of the signal in mV.

[0061] Said frequency associated with said supply voltage allows both the generation and satisfactory bursting of the bubbles in the composition, and only bursting of any bubbles already present in the medium in the composition.

[0062] The electrical signal exciting the transducer(s) may be pulsed, with a pulse duration preferably of between 0.01 s and 0.09 s, in particular equal to 0.03 s or 0.08 s.

[0063] The cyclic ratio Ton / Toff, 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 equal to around 50%, Ton designating the duration for which the transducer is supplied with power during a cycle and Toff the duration for which it is switched off.

[0064] The process may include a step of detecting the presence of the cosmetic composition in contact with the sonotrode, and condition the functioning of the transducer to this detection. The emission of acoustic waves in the absence of composition or when the device is not in the situation of treating the skin or nails is thus avoided.

[0065] Preferably, the acoustic waves are emitted without the sonotrode emission surface 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 into the skin, and promote the cavitation of the bubbles in the composition.

[0066] “The distance between the transducer and the surface to be treated” must be understood to mean the distance between the sonotrode emission surface and the surface to be treated.

[0067] A composition may be circulated continuously in contact with the sonotrode, with continuous functioning of the transducer(s), or, as a variant, pulsed functioning of the transducer(s). The composition can also be fed in a pulsed manner. The feeding of an area subjected to the acoustic waves is advantageously discontinuous, for example with a period of feeding the area while the acoustic waves are not generated, and then a period in which the composition present in the area is subjected to the acoustic waves without being refreshed during this exposure. This makes it possible to prevent the bubbles present in the composition before entering said area from being repelled by the acoustic waves present therein.

[0068] It is thus possible to servocontrol the feeding of the exfoliation area with composition to the functioning of the transducer(s) for the production of the acoustic waves or vice versa, and to have pulsed functioning of the transducer(s) and / or of the feeding with composition. In other words, the supply of composition may be offset in time relative to the period of emission of the acoustic waves into the area into which the composition is supplied.

[0069] The propagation of the acoustic waves is facilitated by the presence of liquid in the composition. The gas / liquid mass ratio in the composition may thus benefit from not being too high, and the composition may advantageously contain a thickener, or any other compound for increasing the temporal stability of the bubbles.

[0070] Abrasion The process may include abrasion of the skin or the nails using abrasive particles and / or a part of the device in contact with the surface to be treated.

[0071] This abrasion may be performed by a device other than that which emits the acoustic waves, by the device itself, or by a specific part mounted on the device, such as a grille, a blade, a scraper, granules adhesively bonded to the device, such as particles of diamond, silica, or any other suitable accessory.

[0072] The part used for the abrasion is for example fitted to perform the abrasion, then removed at the time of exfoliation by bubbles and acoustic waves, and is for example interchangeable with a part of the device used for the exfoliation by acoustic waves and bubbles.

[0073] The part used for the abrasion may also be present during the exfoliation by bubbles and acoustic waves, as will be described below. This part may then take the form of a grille, for example.

[0074] The abrasion may be performed before the cosmetic composition and the bubbles are exposed to the acoustic waves, or, as a variant, concomitantly. When the abrasion takes place beforehand, it may be performed via any means, notably by mechanical or chemical action.

[0075] Grille

[0076] The ultrasonic transducer preferably forms part of a device which further comprises a grille defining a surface for contact with said surface to be treated, the grille having at least one opening, preferably at least two openings, through which the waves emitted by the transducer may propagate toward the surface to be treated.

[0077] The process according to the invention may comprise the step consisting in at least partially exposing the surface of the skin or the nails to acoustic waves while it is in contact with the grille.

[0078] Thanks to the grille, it is possible to exercise more precise control over the distance between the transducer and the surface to be treated, thereby making it possible to enhance the action of the bubbles near said surface while at the same time avoiding direct contact between the transducer and this surface.

[0079] The grille is preferably non- absorbent, in other words it is not porous. The grille may notably not have the capacity to take in water when it is immersed in water, and hold for example less than 10% water, better still less than 5% of its weight of water.

[0080] The grille may in particular be made of a solid material, and therefore not a foam, fabric or felt.

[0081] The surface for contact between the device and the skin or the nails may be defined by a non-absorbent surface of the grille.

[0082] The region of the grille defining the openings therein may be defined by a nonabsorbent part of the grille.

[0083] The grille is preferably removable, in other words it can be easily detached by the user of the device, preferably without the use of a tool. This makes it easier to clean and allows it to be replaced between uses, or even, if so desired, allows several grilles to be interchanged depending on the use, for example by selecting the type of grille best suited to the morphology of the area to be treated.

[0084] The contact surface defined by the grille may be substantially flat, in order for example to keep a substantially constant distance between the transducer and the surface to be treated located facing the surface for emission of the acoustic waves.

[0085] As a variant, the grille may define a contact surface adapted to the morphology of the area to be treated, of domed shape for example.

[0086] The grille may also have, where applicable, an adjustable working diameter. The device may comprise a mechanical element of variable opening such as a diaphragm, arranged in front of or behind the grille, in such a way 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.

[0087] Some or all of the openings in the grille may be closed fully or partially in a controlled manner. This makes it possible, according to the area to be treated, and in particular for more sensitive areas such as areas around the eyes, to limit the surface area and the intensity of treatment, if desired. The device may comprise a shutter that is movable between a position in which it does not cover one or more openings in the grille and a covering position in which the opening(s) are covered at least partially, or even fully. This shutter is for example adjusted manually by the user as needed. Preferably, the grille has a thickness of between 0.1 and 10 mm, better still between 0.5 and 5 mm. This ensures a minimum distance of at least this thickness between the transducer and the surface to be treated, regardless of the position of the grille relative to the transducer.

[0088] The grille is preferably made of a rigid or semi-rigid material, for example metal, or rigid plastic. The grille is for example produced from a material selected from a metal, in particular steel, stainless steel, an alloy, silicone, a polymer, notably of polyurethane (PU), polyethylene terephthalate (PET) or polythiophene (PT) type, or a combination of several of these elements.

[0089] The grille may not deform visibly to the naked eye during normal use, owing to its rigidity. As a variant, the grille may be deformable. Its diameter may be reduced for example by applying mechanical pressure to its contour.

[0090] The grille may comprise recesses, in particular extending in its thickness. The grille comprises deformable channels for example, the diameter of which may vary depending on the pressure applied, extending for example in a non-longitudinal direction. As a variant, the channels may be rigid to allow fluid to pass through even when pressure is applied to the grille. The surface of the channels may be variable and their shape different, for example round, square, or triangular.

[0091] The grille may also have reliefs or be flocked, or not.

[0092] The grille may be produced with reliefs or from a material that is intrinsically rough, so that it has a non- smooth surface for contact with the skin or the nails. Such a surface finish makes it possible to achieve a mechanical abrasive effect that can participate in the exfoliation when the device is moved over the area to be treated during use. The grille may comprise several materials with varying degrees of abrasiveness, for example a more abrasive material at the center of the grille and a less abrasive material on the edges of the grille, or vice versa.

[0093] The device may comprise an element for driving the grille, configured to generate a movement of oscillation, vibration and / or rotation of the grille on the skin. For example, the device comprises a motor for driving the grille in movement, for example rotary, linear, eccentric or the like, alternating or otherwise. The device may comprise a vibrator, where applicable, for vibrating the grille. The amplitude of the movement may be fixed or adjustable. The mechanical abrasive effect may thus be obtained automatically by virtue of the movement imparted by the device to the grille, and impurities may be cleansed more effectively.

[0094] The grille may be produced in various ways.

[0095] The grille may comprise a peripheral frame, which defines the outer contour of the grille when seen face on. This frame may be rigid, in particular more rigid than a central part of the grille, which is perforated.

[0096] The contour of the grille, when seen face on, may have a circular, oval, polygonal, etc. shape, and preferably the grille has a closed contour.

[0097] The opening(s) in the grille may have substantially the same size. The grille may comprise a plurality of openings arranged in a regular grid, for example in rows or in columns.

[0098] As a variant, the opening(s) may be arranged concentrically.

[0099] The openings may have various shapes, in particular portions of disk(s) or ring(s).

[0100] The grille may have a single opening, in particular of non-circular contour, for example in the shape of a slot, cross, polygon, regular or non-regular, or oval. Preferably, the grille has at least two openings, in particular two openings of substantially the same size.

[0101] When there is a single opening, this may be centered or not.

[0102] A grille having a fine mesh improves the retention of the surface to be treated during use of the device, which allows better control over a constant distance between said surface to be treated and the surface for emission of the acoustic waves, and thus over the phenomenon of cavitation.

[0103] An opening in the grille may have an area of at least 1 mm2. A smaller dimension of an opening in the grille, when seen face on, is for example at least 0.5 mm.

[0104] Preferably, the grille has a ratio of the total surface area of the openings relative to the surface area of the grille for contact with the skin or the nails of greater than or equal to 0.3, better still 0.5, even better still 0.8.

[0105] Such a ratio makes it possible to prevent the skin or the nails from coming into contact with the transducer or from being deformed, while still having enough openings for the ultrasonic waves to reach the area to be treated or its vicinity over a sufficient extent to obtain the desired result. The acoustic waves may propagate through at least one or two openings in the grille.

[0106] The grille may be moved during exfoliation, for example intermittently, remaining stationary for a certain time and then being moved incrementally, along the surface to be treated. The grille may also be moved continuously over the surface to be treated.

[0107] Circulation of the composition in the grille

[0108] The device may further comprise at least one duct extending in the grille.

[0109] Such a device makes it possible to apply the cosmetic composition continuously, i.e. 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.

[0110] When circulation is established in a closed circuit, the device may comprise at least one return duct 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 duct extending in the grille.

[0111] Process

[0112] The process according to the invention may be performed on naked skin, on the scalp or on the nails.

[0113] The process may comprise passing the device, in particular vertically from top to bottom in the case of the facial skin, one or more times over the surface of the skin during exfoliation.

[0114] The transducer may be moved with a translational and / or rotational movement relative to said surface during exfoliation.

[0115] The transducer may be moving for the whole duration of the treatment, or if not, static relative to said surface for a duration not exceeding 0.5 s, better still 1 s.

[0116] The contact pressure of the device on the surface to be treated may be greater than or equal to 0.2 N / cm2during exfoliation, this contact pressure being in particular the pressure of the grille on the surface to be treated, or the pressure of another element of the device in contact with the surface to be treated, in particular a non- smooth or rough element. Related processes

[0117] The process according to the invention may be preceded or followed by another cosmetic process.

[0118] In one example, a surface of the skin is exfoliated by performing the process according to the invention, and a care treatment is then performed on the exfoliated area (for example just after or less than two hours after), for example a massage.

[0119] Treatment kit

[0120] The invention also relates to a treatment kit for performing the process according to the invention, as defined above.

[0121] This kit comprises: the cosmetic composition in which the bubbles are generated, a device for exposing the cosmetic composition to acoustic waves in the vicinity of the surface to be treated.

[0122] The composition may or may not be packaged with the device in the same packaging.

[0123] 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 fully or partially fitted in a corresponding housing of the device, or to be connected to the device via a suitable connection such as a hose.

[0124] Other compounds

[0125] The composition may generally comprise any compound conventionally included in the formulation of compositions for cleansing and / or caring for human skin, which is compatible with the generation of bubbles that are sufficiently stable during the application of the acoustic waves.

[0126] Process for preparing and treating keratin material

[0127] The invention also relates, according to another of its aspects, to a process for the preparation and treatment of human keratin material, in particular the skin or the scalp, comprising the steps consisting in: (a) pretreating a surface of said keratin material by subjecting it to a first cosmetic composition and to ultrasonic acoustic waves emitted by a device comprising at least one ultrasonic transducer, with an acoustic intensity Isata in the region exposed to the acoustic waves that is at least equal to 0.1 W / cm2, i) the transducer being moved relative to said surface at an average sweeping speed of between 0.01 cm2 / s and 15 cm2 / s for the duration of treatment of said surface, and / or ii) the device being applied to a location on the keratin material, then moved away from the latter and applied to a different location, and

[0128] (b) applying a second cosmetic composition to said surface of the keratin material.

[0129] The method of application of step ii) corresponds to what is referred to as moving by “tapping”, wherein the device is applied to the keratin material via a succession of movements toward and away from said material while shifting its position each time. Coverage of the area treated may be achieved to a greater or lesser extent between two successive contacts; for example, between 10 and 90% of the area treated during a contact may be treated during the next contact.

[0130] The method of application of step i) may be carried out without the device losing contact with the keratin material.

[0131] The process may comprise only the method of application of step i). Alternatively, the process comprises only the method of application of step ii).

[0132] There may also be hybrid operation, with a mixture of tapping and a sweeping action in contact with said material, in other words while the device is in contact with said material the device is moved around in contact with the latter and phases of contact between the device and said material are alternated with phases of shifting the device without contact with said material. The process may therefore comprise both the method of application of step i) and the method of application of step ii).

[0133] It is thus possible to generate, in step (a), within the first cosmetic composition, bubbles near the surface of the keratin material to be treated and cause these bubbles to burst, in conjunction with a shock wave. This makes it possible to prepare the keratin material for better and faster absorption of the second composition by said material. The acoustic intensity and the speed selected ensure a good compromise between ease of use and effectiveness of the preparation of said keratin material.

[0134] The method according to the invention is implemented in particular as a cosmetic and non-therapeutic process in order to enhance the effects of any type of treatment for improving the surface of keratin material as well as the biology thereof.

[0135] The term “cosmetic composition” denotes a composition containing at least one cosmetic active agent, as defined in the Cosmetics Directive 76 / 768 / EEC. According to the invention, mineral water or running water does not constitute a cosmetic composition.

[0136] The surface layers of the skin may be prepared and treated in particular. The area of skin that is prepared and treated according to the invention may be the skin of the face, neckline, back, arms, legs, hands and / or feet, and the scalp or the nails. The process according to the invention is most particularly suitable for the preparation and treatment of facial skin, notably of the forehead, cheeks, chin, neck, nose and scalp.

[0137] Step (a) according to the invention makes it possible in particular to remove or effectively treat impurities, in particular endogenous and / or exogenous impurities, and step (a) consists for example in exfoliating the keratin material.

[0138] Endogenous impurities may include dead cells, dead skin, dandruff, excess sebum, sweat and blackheads. Exogenous impurities may include makeup, environmental pollution, dust, microorganisms, or any type of preparation.

[0139] Thus, the surface treated is more receptive to the second composition which is applied in step (b) and the process may allow better absorption of the active agent(s) contained in the second composition. The surface treated is also more receptive to the first composition.

[0140] The acoustic waves make it possible to cause complete cavitation of bubbles within the first composition in order to generate a mechanical effect on the keratin material to be prepared.

[0141] “Complete cavitation” in this case means both generating and bursting bubbles, giving rise to a mechanical impact on neighbouring surfaces. The first cosmetic composition may or may not have bubbles already present within it before the acoustic waves are applied. The first composition may also have a gas dissolved in it, for example carbon dioxide, dinitrogen, dioxygen, or any gas that can dissolve in the composition. The first composition may include cosmetic active agents that can penetrate the keratin material and / or help prepare the keratin material with the bubbles.

[0142] The bubbles generated and / or present may also contribute toward the release of chemical species which contribute toward the preparation of the keratin material, such as free radicals.

[0143] The speed of sweeping corresponds to the extent of surface area per unit time which enters the area located under the acoustic wave emission surface and which was not therein before.

[0144] First cosmetic composition

[0145] Preferably, the first cosmetic composition contains at least one surfactant, in particular with a total concentration by mass of surfactant(s) in the first composition of less than or equal to 3%, even less than or equal to 1%.

[0146] The surfactant(s) in particular contribute toward the suspension of impurities by forming micelles, and thus contribute toward removal of impurities.

[0147] A relatively low total content of surfactant(s), in particular less than or equal to 1% by mass, in the first cosmetic composition makes it possible to reduce the ecological footprint of said cosmetic composition and to limit the undesirable effects of surfactants on the skin, such as irritation and allergies.

[0148] The first cosmetic composition preferably has a total concentration by mass of surfactant(s) of between 0.01% and 20% by weight with respect to the total mass of the composition, better still between 0.01% and 5%, even better still 0.01% and 1.5%, even better still between 0.01% and 1%.

[0149] The surfactants may contribute toward the formation of the bubbles and / or toward their stabilization, these surfactants being chosen, for example, from foaming surfactants such as polyoxyalkylenated alkyl(amido) ether carboxylic acid anionic surfactants, anionic surfactants different from the abovementioned polyoxyalkylenated alkyl(amido) ether carboxylic acids, nonionic surfactants, amphoteric and zwitterionic surfactants, and mixtures thereof, and / or are chosen from the compounds conventionally present in makeup-removing compositions such as alkylpolysaccharides, fatty alcohol polyethylene glycols, oils, and mixtures thereof. Any surfactant that can generate micelles in the medium may be used. The first composition may comprise at least one active agent referred to as a peeling agent, selected from among 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 agent may be in a concentration by mass of between 0.01% and 10% by mass, for example.

[0150] The first cosmetic composition placed in contact with the keratin material may be at least partially recovered and / or recycled.

[0151] The first cosmetic composition may be applied continuously, i.e. 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.

[0152] The first composition may generally comprise any compound conventionally included in the formulation of compositions for cleansing and / or caring for human keratin material, which is compatible with the generation of bubbles that are sufficiently stable during the application of the acoustic waves.

[0153] Second cosmetic composition

[0154] The second cosmetic composition may comprise any constituent usually employed in the envisaged topical application and administration.

[0155] The second cosmetic composition may comprise at least one aqueous phase. The aqueous phase may comprise water and optionally a water-soluble solvent. Among the water-soluble solvents that may be used in a composition in accordance with the invention, mention may be made notably of lower monoalcohols containing from 1 to 5 carbon atoms, such as ethanol and isopropanol, C2-C32 polyols, C3 and C4 ketones and C2-C4 aldehydes.

[0156] The second cosmetic composition may comprise at least one fatty phase, in particular an oily phase. The fatty phase may notably comprise oils, waxes or pasty fatty substances. Preferably, the fatty phase comprises at least one oil, notably a cosmetic oil. For example, the fatty phase may comprise at least hydrocarbon-based, silicone, fluoro or nonfluoro oils, or mixtures thereof. The oils may be volatile or non-volatile.

[0157] The second cosmetic composition may be aqueous and / or comprise hydrophilic active agents.

[0158] The second cosmetic composition may be anhydrous, for example it may be an oil or a balm, and / or comprise lipophilic active agents. The second cosmetic composition may comprise at least one standard cosmetic ingredient that may be selected in particular from sunscreens, gelling agents and thickeners, hydrophilic or lipophilic cosmetic active agents, colorants, fillers, dispersants, surfactants, and mixtures thereof.

[0159] As cosmetic active agents, mention may for example be made of moisturizers, desquamating agents, humectants, anti-aging agents, mattifying agents, cicatrizing agents, antibacterial agents, vitamins and derivatives or precursors thereof, antioxidants, sunscreens, free -radical scavengers; anti-pollutants; self-tanning agents; anti-glycation agents; calmatives; deodorant agents; essential oils; NO-synthase inhibitors; agents for stimulating the synthesis of dermal or epidermal macromolecules and / or for preventing degradation thereof; agents for stimulating fibroblast proliferation; agents for stimulating keratinocyte proliferation; muscle relaxants; refreshing agents; tensioning agents; depigmenting agents; propigmenting agents; keratolytic agents; thinning agents; agents which act on cell energy metabolism; insect repellents; substance P antagonists or CRGP antagonists; agents for preventing hair loss; and mixtures thereof.

[0160] The second cosmetic composition may also comprise at last one adjuvant that is common in the cosmetic field, chosen from fragrances, film-forming polymers, pH adjusters (acid or base), for example citric acid, tartaric acid or oxalic acid, chelating agents, preserving agents, softeners, sweeteners, antifoaming agents, trace elements, propellants, and mixtures thereof.

[0161] Of course, a person skilled in the art will take care to select the compound(s), and / or the amount thereof, such that the advantageous properties of a compound according to the invention are not, or are not substantially, adversely affected by the envisioned addition.

[0162] The second composition is preferably suitable for topical application to keratin material and thus generally comprises a physiologically acceptable medium, i.e. a medium that is compatible with keratin material.

[0163] It is preferably a cosmetically acceptable medium, i.e. a medium which has a pleasant colour, odour and feel and which does not cause any unacceptable discomfort, i.e. stinging or tautness, liable to discourage the user from applying this composition.

[0164] The second cosmetic composition may be prepared according to techniques that are well known to those skilled in the art. It may be in any conventional presentation form depending on the targeted applications and is suitable for topical application, i.e. application to the surface of the keratin material under consideration.

[0165] The second composition may be in the form of an aqueous or aqueous-alcoholic gel. It may be in the form of a simple or complex emulsion (O / W, W / O, O / W / O or W / O / W), such as a cream, a milk or a cream-gel. It may also be in anhydrous form, for example in the form of an oil.

[0166] The second cosmetic composition may for example be used as a makeup product. The second cosmetic composition may be used, for example, as a care and / or antisun product for the face and / or body, of liquid to semi-liquid consistency, and may have the appearance of a more or less unctuous white or coloured cream, an ointment, a milk, a cream-gel, a lotion, a serum, a paste or a mousse. It may optionally be applied to the keratin material in aerosol form. It may also be in solid form, for example in the form of a stick.

[0167] The second cosmetic composition may be in the form of a product for caring for keratin material or semi-mucous membranes, such as a protective or cosmetic care composition for the face, for the lips, for the hands, for the feet, for the anatomical folds or for the body (for example day cream, night cream, day serum, night serum, makeupremoving cream, makeup base, protective or care body milk, aftersun milk, skincare or scalpcare lotion, gel or mousse, serum, mask, or aftershave composition).

[0168] More specifically, the second cosmetic composition is intended for topical application. Preferably, such a composition is not intended to be rinsed off after application.

[0169] The second cosmetic composition may advantageously exhibit a firm and compact feel when taken up. It may be thick on application and then become transformed, melt and release freshness.

[0170] The second cosmetic composition alternatively can be in the form of a face and / or body care or makeup product, and can be packaged, for example, in the form of a cream in a jar or a fluid in a tube or a pump bottle or a dropper bottle.

[0171] The second cosmetic composition may comprise one or more molecules having a logP between -0.5 and 15. The logP should be understood to mean the logarithm of the ratio of the concentrations of the molecule in question in octanol and in water.

[0172] The second cosmetic composition may comprise one or more molecules having a molecular weight of between 50 g / mol and 2 M Dalton. Acoustic waves

[0173] The acoustic intensity Isata may be defined as the average acoustic power on the surface subjected to the acoustic waves, divided by said surface: ISATA=Pave. / S the average acoustic power taking into account the cyclic ratio when the electrical supply signal of the transducer is pulsed.

[0174] The acoustic intensity Isata is preferably between 0.1 and 10 W / cm2, better still between 1 and 5 W / cm2, even better still 2.5 and 5 W / cm2, even better still between 3 and 4 W / cm2.

[0175] The energy delivered by the device onto said surface is preferably between 0.1 J / cm2and 15 J / cm2, better still between 0.1 J / cm2and 10 J / cm2, during the pretreatment step (a).

[0176] The acoustic waves may be generated by a single transducer or, as a variant, by at least two transducers.

[0177] The only bubbles of air present in the first composition may be those generated by the acoustic waves.

[0178] Each transducer comprises one or more electroactive elements for converting an electric current into mechanical vibration, this or these electroactive elements being for example based on piezoelectric materials, as described in detail below.

[0179] This or these electroactive elements may be coupled to a sonotrode that may be set in mechanical resonance by the electroactive element or elements and serves to define a surface for emission of the acoustic waves toward the target surface or volume.

[0180] The acoustic waves may be generated permanently as soon as the treatment device is switched on or, as a variant, may be generated only when certain operating conditions are met, for instance the presence of the first 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 there is dirt in the area.

[0181] As a variant, the acoustic waves may be generated only when the amount of first composition in contact with the surface to be treated is sufficient, or when certain conditions for generating cavitation are detected, such as a minimum height of first composition surrounding the sonotrode, a first composition or transducer temperature lying in a given range, or the like. The surface area for emission of the acoustic waves ranges for example from the surface area of a circle 2 mm in diameter to a circle 100 mm in diameter, better still from the surface area of a circle 5 mm in diameter to the surface area of a circle of 50 mm, even better from the surface area of a circle 5 mm in diameter to the surface area of a circle of 40 mm, in particular the surface area for emission of the acoustic waves is substantially equal to the surface area of a circle 12 mm in diameter.

[0182] They may be generated by a sinusoidal or non-sinusoidal electrical signal or by a signal of more complex shape, for example with frequency modulation or with amplitude modulation. The acoustic waves are preferably emitted at a single frequency, which may enable them to be focused more precisely on a given area, but, as a variant, may be emitted at several different frequencies.

[0183] Said frequency is preferably between 10 and 500 kHz, better still 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 around 34 kHz.

[0184] The transducer supply voltage is preferably between 50 mVpp and 500 mVpp, this voltage is preferably amplified between 95 mVpp and 265 mVpp. The transducer supply voltage is for example between 130 mVpp and 160 mVpp, amplified between 248 mVpp and 331 mVpp.

[0185] Said frequency associated with said supply voltage allows both the generation and satisfactory bursting of the bubbles in the first composition, and only bursting of any bubbles already present in the medium in the first composition.

[0186] The electrical signal exciting the transducer(s) may be pulsed, with a pulse duration preferably of between 0.01 s and 0.09 s, in particular equal to 0.03 s or 0.08 s. As a variant, the electrical signal exciting the transducer(s) is not pulsed.

[0187] The cyclic ratio Ton / Toff, when the signal is pulsed, is preferably between 1% and 99%, better still between 5% and 95%, better still between 10% and 90%, better still between 30% and 80%, even better still between 50% and 70%, for example equal to around 50%, Ton designating the duration for which the transducer is supplied with power during a cycle and Toff the duration for which it is switched off.

[0188] The process may include a step of detecting the presence of the first cosmetic composition in contact with the sonotrode, and condition the functioning of the transducer to this detection. This detection is performed for example by measuring the impedance of the system.

[0189] The emission of acoustic waves in the absence of first composition or when the device is not in the situation of treating keratin material is thus avoided.

[0190] Preferably, the acoustic waves are emitted without the sonotrode emission surface 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 keratin material is exposed to the acoustic waves, which makes it possible to limit the acoustic energy emitted into the keratin material, and promote the cavitation of the bubbles in the first composition.

[0191] The distance between the transducer and the surface to be treated must be understood to mean the distance between the sonotrode emission surface and the surface to be treated.

[0192] The first composition may be circulated continuously in contact with the sonotrode, with continuous functioning of the transducer(s), or, as a variant, pulsed functioning of the transducer(s). The first composition can also be fed in a pulsed manner. The feeding of an area subjected to the acoustic waves is advantageously discontinuous, for example with a period of feeding the area while the acoustic waves are not generated, and then a period in which the first composition present in the area is subjected to the acoustic waves without being refreshed during this exposure. This makes it possible to prevent the bubbles present in the first composition before entering said area from being repelled by the acoustic waves present therein. As a variant, the first composition may not be refreshed in the area subjected to the acoustic waves during step (a), in other words where there is a feed circuit, this does not deliver any more composition. Feeding with first composition, for example with a view to its recycling, may thus be temporarily interrupted when the surface to be treated is exposed to the acoustic waves.

[0193] It is thus possible to servocontrol the feeding of the exfoliation area with first composition to the functioning of the transducer(s) for the production of the acoustic waves or vice versa, and to have pulsed functioning of the transducer(s) and / or of the feeding with first composition. In other words, the supply of first composition may be offset in time relative to the period of emission of the acoustic waves into the area into which the first composition is supplied. The propagation of the acoustic waves is facilitated by the presence of liquid in the first composition. The gas / liquid mass ratio in the first composition may thus benefit from not being too high, and the first composition may advantageously contain a thickener, or any other compound for increasing the temporal stability of the bubbles.

[0194] Abrasion

[0195] The process may include abrasion, before or at the same time as the pretreatment step (a), of the keratin material using abrasive particles and / or a part of the device in contact with the surface to be treated.

[0196] This abrasion may be performed by a device other than that which emits the acoustic waves, by the device itself, or by a specific part mounted on the device, such as a grille, a blade, a scraper, granules adhesively bonded to the device, such as particles of diamond, silica, or any other suitable accessory.

[0197] The part used for the abrasion is for example fitted to perform the abrasion, then removed at the time of exfoliation by bubbles and acoustic waves, and is for example interchangeable with a part of the device used for the exfoliation by acoustic waves and bubbles.

[0198] The part used for the abrasion may also be present during the exfoliation by bubbles and acoustic waves, as will be described below. This part may then take the form of a grille, for example.

[0199] The abrasion may be performed before the cosmetic composition and the bubbles are exposed to the acoustic waves, or, as a variant, concomitantly. When the abrasion takes place beforehand, it may be performed via any means, notably by mechanical or chemical action.

[0200] Grille

[0201] The ultrasonic transducer preferably forms part of a device which further comprises a grille defining a surface for contact with said surface to be treated, the grille having at least one opening, preferably at least two openings, through which the waves emitted by the transducer may propagate toward the surface to be treated. The process according to the invention may comprise the step consisting in at least partially exposing the surface of the keratin material to acoustic waves while it is in contact with the grille.

[0202] Thanks to the grille, it is possible to exercise more precise control over the distance between the transducer and the surface to be treated, thereby making it possible to enhance the action of the bubbles near said surface while at the same time avoiding direct contact between the transducer and this surface.

[0203] The grille is preferably non- absorbent, in other words it is not porous.

[0204] The grille may notably not have the capacity to take in water when it is immersed in water, and hold for example less than 10% water, better still less than 5% of its weight of water. The grille may have undergone a treatment to enhance its wettability in the first composition.

[0205] The grille may in particular be made of a solid material, and therefore not a foam, fabric or felt.

[0206] The surface for contact between the device and the keratin material may be defined by a non-absorbent surface of the grille.

[0207] The region of the grille defining the openings therein may be defined by a nonabsorbent part of the grille.

[0208] The grille is preferably removable, in other words it can be easily detached by the user of the device, preferably without the use of a tool. This makes it easier to clean and allows it to be replaced between uses, or even, if so desired, allows several grilles to be interchanged depending on the use, for example by selecting the type of grille best suited to the morphology of the area to be treated.

[0209] The contact surface defined by the grille may be substantially flat, in order for example to keep a substantially constant distance between the transducer and the surface to be treated located facing the surface for emission of the acoustic waves.

[0210] As a variant, the grille may define a contact surface adapted to the morphology of the area to be treated, of domed shape for example.

[0211] The grille may also have, where applicable, an adjustable working diameter. The device may comprise a mechanical element of variable opening such as a diaphragm, arranged in front of or behind the grille, in such a way 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.

[0212] Some or all of the openings in the grille may be closed fully or partially in a controlled manner. This makes it possible, according to the area to be treated, and in particular for more sensitive areas such as areas around the eyes, to limit the surface area and the intensity of treatment, if desired. The device may comprise a shutter that is movable between a position in which it does not cover one or more openings in the grille and a covering position in which the opening(s) are covered at least partially, or even fully. This shutter is for example adjusted manually by the user as needed.

[0213] Preferably, the grille has a thickness of between 0.1 and 10 mm, better still between 0.5 and 5 mm. This ensures a minimum distance of at least this thickness between the transducer and the surface to be treated, regardless of the position of the grille relative to the transducer.

[0214] The grille may be attached to a fixed or movable spacer, the spacer being attached to the device and making it possible in particular to keep a space between the grille and the surface of the transducer. It may form a chamber with the surface of the transducer or the attachment part from which it protrudes from the surface of the transducer.

[0215] The grille is preferably made of a rigid or semi-rigid material, for example metal, or rigid plastic. The grille is for example produced from a material selected from a metal, in particular steel, stainless steel, an alloy, silicone, a polymer, notably of polyurethane (PU), polyethylene terephthalate (PET) or polythiophene (PT) type, or a combination of several of these elements.

[0216] The grille may not deform visibly to the naked eye during normal use, owing to its rigidity. As a variant, the grille may be deformable. Its diameter may be reduced for example by applying mechanical pressure to its contour.

[0217] The grille may comprise recesses, in particular extending in its thickness. The grille comprises deformable channels for example, the diameter of which may vary depending on the pressure applied, extending for example in a non-longitudinal direction. As a variant, the channels may be rigid to allow fluid to pass through even when pressure is applied to the grille. The surface of the channels may be variable and their shape different, for example round, square, or triangular.

[0218] The grille may also have reliefs or be flocked, or not. The grille may be produced with reliefs or from a material that is intrinsically rough, so that it has a non-smooth surface for contact with the keratin material. Such a surface finish makes it possible to achieve a mechanical abrasive effect that can participate in the exfoliation when the device is moved over the area to be treated during use. The grille may comprise several materials with varying degrees of abrasiveness, for example a more abrasive material at the center of the grille and a less abrasive material on the edges of the grille, or vice versa.

[0219] The device may comprise an element for driving the grille, configured to generate a movement of oscillation, vibration and / or rotation of the grille. For example, the device comprises a motor for driving the grille in movement, for example rotary, linear, eccentric or the like, alternating or otherwise. The device may comprise a vibrator, where applicable, for vibrating the grille. The amplitude of the movement may be fixed or adjustable.

[0220] The mechanical abrasive effect may thus be obtained automatically by virtue of the movement imparted by the device to the grille, and impurities may be cleansed more effectively.

[0221] The grille may be produced in various ways.

[0222] The grille may comprise a peripheral frame, which defines the outer contour of the grille when seen face on. This frame may be rigid, in particular more rigid than a central part of the grille, which is perforated.

[0223] The contour of the grille, when seen face on, may have a circular, oval, polygonal, etc. shape, and preferably the grille has a closed contour.

[0224] The opening(s) in the grille may have substantially the same size. The grille may comprise a plurality of openings arranged in a regular grid, for example in rows or in columns.

[0225] As a variant, the opening(s) may be arranged concentrically.

[0226] The openings may have various shapes, in particular portions of disk(s) or ring(s).

[0227] The grille may have a single opening, in particular of non-circular contour, for example in the shape of a slot, cross, polygon, regular or non-regular, or oval. Preferably, the grille has at least two openings, in particular two openings of substantially the same size.

[0228] When there is a single opening, this may be centered or not. A grille having a fine mesh improves the retention of the surface to be treated during use of the device, which allows better control over a constant distance between said surface to be treated and the surface for emission of the acoustic waves, and thus over the phenomenon of cavitation.

[0229] An opening in the grille may have an area of at least 1 mm2. A smaller dimension of an opening in the grille, when seen face on, is for example at least 0.5 mm.

[0230] Preferably, the grille has a ratio of the total surface area of the openings relative to the surface area of the grille for contact with the keratin material of greater than or equal to 0.3, better still 0.5, even better still 0.8.

[0231] Such a ratio makes it possible to prevent the keratin material from coming into contact with the transducer or from being deformed, while still having enough openings for the ultrasonic waves to reach the area to be treated or its vicinity over a sufficient extent to obtain the desired result.

[0232] The acoustic waves may propagate through at least one or two openings in the grille.

[0233] The grille may be moved during exfoliation, for example intermittently, remaining stationary for a certain time and then being moved incrementally, along the surface to be treated. The grille may also be moved continuously over the surface to be treated.

[0234] Circulation of the composition in the grille

[0235] The device may further comprise at least one duct extending in the grille.

[0236] Such a device makes it possible to apply the first cosmetic composition continuously or non-continuously, or alternately with the application of the ultrasound, i.e. circulation of the first composition is established in contact with the surface to be treated, this circulation taking place, for example, in a closed or open circuit.

[0237] When circulation is established in a closed circuit, the device may comprise at least one return duct connected to a suction pump, making it possible to recover at least partially the first composition in the vicinity of the surface to be treated, in particular at least one duct extending in the grille.

[0238] Method The process according to the invention may be performed on naked skin, on the scalp, on the nails or on the hair.

[0239] Step (a) of the process may comprise passing the device, in particular vertically from top to bottom in the case of the facial skin, one or more times over the surface of the skin. The device may be passed over a horizontal surface, in particular in several back and forth movements.

[0240] The transducer may be moved with a translational and / or rotational movement relative to said surface.

[0241] The transducer may be moving for the whole duration of the treatment of step (a), or if not, static relative to said surface for a duration not exceeding 0.5 s, better still 10 seconds.

[0242] The speed of sweeping of the surface by the transducer, in step (a), may be between 5 and 15 cm2 / s.

[0243] The contact pressure of the device on the skin to be treated may be greater than or equal to 0.1 N / cm2during step (a).

[0244] The second composition may be applied in step b) as soon as the treatment of step a) is finished, or as a variant, a little later, preferably less than 10 min after the end of step a), better still less than 5 min after the end of step a).

[0245] The surface to which the second composition is applied in step b) is preferably dry.

[0246] The second composition may be applied in step b) by hand or using an applicator, including an applicator forming part of the device used for the treatment in step a). The second composition may be applied in step b) using the device with which the first composition is delivered or with another hand-operated device, and the device applying the second composition may be motorized or non-motorized. The second composition may be contained in a container, such as a cartridge, forming part of the device for applying the second composition, or in attached packaging.

[0247] The process may include a step consisting in rinsing said surface of the keratin material between step (a) and step (b). Said surface is notably rinsed with water.

[0248] The process may include an additional step of pretreatment of said surface of the keratin material, upstream of step (a), in particular a step comprising the application of an additional cosmetic composition to said surface and / or rinsing said surface. An additional step of preparation of the skin after step (a) may be performed before step (b).

[0249] Treatment kit

[0250] The invention also relates to a treatment assembly (kit) for performing the process according to the invention, as defined above.

[0251] This assembly advantageously comprises, in particular within the same packaging: the first cosmetic composition comprising a surfactant and / or an active agent selected from fruit acids, hydrochloric acid, citric acid, acetic acid, keratolytic compounds, in particular salicylic acid, a device for exposing the first cosmetic composition to acoustic waves in the vicinity of the surface to be prepared, and the second cosmetic composition for treating said surface.

[0252] The compositions may or may not be packaged with the device in the same packaging. The compositions may be packaged in packaging that is separate, or secondary, with respect to the packaging of the device.

[0253] Where appropriate, the first composition is contained in a container arranged to be mounted on the device, this container constituting, for example, a cartridge arranged to be fully or partially fitted in a corresponding housing of the device, or to be connected to the device via a suitable connection such as a hose. This container may be used alone in the device for delivering the first composition.

[0254] Brief description of the drawings

[0255] A clearer understanding of the invention may be gained from reading the following detailed description of non-limiting examples of embodiments, and from studying the appended drawing, in which:

[0256] [Fig 1] schematically and partially depicts an example of a device for treating human skin implementing the process according to the invention,

[0257] [Fig 2] schematically and partially depicts a handpiece of the device of figure 1,

[0258] [Fig 3] schematically and partially depicts the device of figure 1 with a reservoir detached from the handpiece,

[0259] [Fig 4] schematically and partially depicts the device of figure 1 in the form of a block diagram,

[0260] [Fig 5] schematically and partially depicts a treatment head of the device of figure 1 comprising a grille,

[0261] [Fig 6A], [Fig 6B], [Fib 6C], [Fig 6D], [Fig 6E] and [Fig 6F] schematically and partially depict variant embodiments of the grille of figure 5,

[0262] [Fig 7] shows the skin exfoliation performance under various conditions,

[0263] [Fig 8] depicts the various strata of the skin,

[0264] [Fig 9A] to [Fig 9D] show the performance in terms of absorption of a cosmetic composition by the skin after various pretreatment conditions.

[0265] Detailed description

[0266] Figures 1 to 4 depict a treatment device 1 for exfoliating the skin K, designed to implement the process according to the invention, comprising a handpiece 2 and a cradle 3.

[0267] Handpiece

[0268] The handpiece 2 comprises a handle 4, a treatment head 5, a circuit 6 for circulating a composition C and at least one reservoir 7 containing this composition C.

[0269] The reservoir 7 makes it possible, during the operation of the device, to compensate for any losses of composition, in the event that a portion thereof is not recycled. The reservoir 7 is preferably detachable from the handpiece, as shown in figure 3. As a variant, the reservoir 7 is not detachable from the handpiece.

[0270] The reservoir preferably comprises an at least partially transparent wall 15 allowing a user to see how much cosmetic composition is in the reservoir 7.

[0271] The circuit 6 comprises a forcing pump 11 schematically depicted in figure 4. The pump 11 may have any type of drive, notably manual or electric, and preferably electric. It may be of varying type. The pump 11 is for example a positive-displacement pump or centrifugal pump, notably a peristaltic pump, diaphragm pump, or piston pump, or a combination of several types of pump. The pump 11 may be powered by direct current or alternating current. As a preference, the power supply voltage of the pump 11 is less than 50 V, being for example powered at a voltage ranging from 5 to 12 V. The pump 11 is preferably compatible with liquids of varying nature, notably aqueous, oily, mixed liquids containing particles or fillers in suspension, or even polymers. The mechanism of the pump 11 may be driven as direct drive from a motor or via a reduction gear. When the drive is a manual drive, the device 1 may comprise a handle that the user actuates in order to operate the pump 11. As a preference, the pump 11 is configured to provide a fluid flow rate of between 0.01 ml and 15 ml per second. The pump 11 may or may not be removable. The pump 11 may generate a negative and / or positive pressure on the fluid in order to cause the fluid to circulate and bring it into contact with the skin. The pump may also be used for the internal cleaning of all or part of the device. The pump 11 may contain a single-part or multipart filter. The pump 11 can be mechanically or electrically isolated in the device 1, for example so that it can be removed from the device 1 for cleaning.

[0272] The treatment head 5 comprises a surface 10 in contact with the composition C, the treatment head 5 being designed to deliver the composition C to an area of the skin K that is to be treated.

[0273] 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 defined for example by a free end of the sonotrode. Bubbles may be generated in the composition C as a result of the acoustic waves owing to the power and frequency of the acoustic waves.

[0274] The transducer 13 may be powered with direct current or alternating current from an electric power source. The acoustic power delivered by the transducer 13 may vary according to the supply voltage of the transducer and / or according to the current with which the transducer is powered, notably according to whether it is a direct current or an alternating current.

[0275] The emission surface 10 for emitting the acoustic waves toward the liquid medium may comprise reliefs or etchings from which the bubbles may originate at different levels along the longitudinal axis of the transducer 13. In particular, these reliefs may offer nucleation sites at their tip and at their base. The reliefs may allow a more uniform production of bubbles. These reliefs may also encourage bursting of the bubbles because the differences in level along the longitudinal axis make it possible to generate relatively extensive cavitation zones that are not restricted to a single plane. In addition to the reliefs on the emission surface 10, which contribute to improving the production of bubbles, the emission surface may have reliefs that pursue another goal, for example that of retaining the fluid or of cleaning the area that is to be treated. These for example are reliefs made of a flexible material, for example bristles, notably flocking.

[0276] The handpiece 2 comprises an electronic circuit 14 notably comprising a control unit 19.

[0277] The control unit 19 has control over the operation of the pump 11, of a battery 18 powering the device (notably the charging thereof) and of the transducer 13.

[0278] The control unit 19 is connected by connections to an electronic generator 16 notably powering the transducer 13. This generator 16 comprises for example an oscillator and a power stage.

[0279] The battery 18 may be removable; it may be used for powering the entirety of the device 1, or just part, notably the pump 11. The battery 18 may be of varying type, for example Li-ion or NiMH, preferably of a type suited to wet conditions or which can be at least partially immersed in a liquid. The battery 18 is preferably rechargeable. The battery 18 is preferably selected to be able, without needing to be recharged, to power the device 1 for a number of consecutive exfoliation sessions, or even several exfoliation sessions and one cleaning of the device 1.

[0280] The handpiece 2 may comprise a grille 20 in contact with the skin to be treated, comprising for example regular openings arranged in rows and in columns, as shown in figure 5. The grille 20 may be produced in various ways.

[0281] The grille 20 comprises at least one opening 300; it may comprise exactly one opening, as shown in figure 6F, or exactly two openings, as shown in figure 6A, or more.

[0282] Most, or all, of the openings may have a similar size, as shown in figure 6B, figure 6D or figure 6E. They may have various shapes, for example square, round, or a portion of a disk or ring, as shown in figure 6C.

[0283] The grille 20 preferably has a ratio of the total surface area of the openings relative to the surface area for contact with the skin of greater than or equal to 0.5, which offers openings large enough for the shock wave generated by the bursting of the bubbles to reach the skin K over a suitable surface area.

[0284] The grille 20 may have a circular contour, as shown in figures 6A to 6F, or a contour having another shape, for example polygonal.

[0285] The outer face of the grille 20 may be flat, and oriented for example parallel to the surface 10.

[0286] The grille 20 may be made in one piece, produced by machining or injection moulding for example.

[0287] Its thickness may be selected in such a way as to ensure it has the desired rigidity.

[0288] The grille 20 may be made of metal, with a smooth or rough surface finish on its face that comes into contact with the skin. The grille 20 is for example made of aluminum or aluminum alloy, or of stainless steel. The grille 20 may also be made of rigid plastic, or of ceramic. The grille 20 may also be a composite, and comprise for example a framework embedded in a plastic matrix.

[0289] The grille 20 may be made of a deformable and / or compressible material. The grille 20 may thus be compressed during use to a thickness that ensures a minimum distance between the emission surface and the surface of the skin to be treated.

[0290] A smooth surface finish of the grille 20 can facilitate movement over the skin in particular, while a rough surface finish may exert a mechanical action contributing toward exfoliation of the skin.

[0291] Each opening in the grille 20 may be delimited by a sharp edge, on the face applied to the skin. Such a sharp edge may promote exfoliation, by scraping the skin as the grille is moved while they are in contact.

[0292] Cosmetic composition supply and return ducts may extend in the grille 20. Cradle

[0293] The cradle 3 comprises, as shown in figure 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 oriented downward. The reservoir 7 may be received in the housing 9 of the cradle, while the handpiece 2 detached from the reservoir 7 is received in the housing 8 of the cradle 3.

[0294] The cradle 3 may accommodate other accessories necessary for the operation of or for recharging the device. The cradle 3 may notably accommodate accessories, such as a thin brush, a key or a screwdriver, necessary for dismantling and / or cleaning internal or removable parts of the device.

[0295] The device is for example charged via a USB port (not depicted) notably sited on the cradle 3. The cradle 3 comprises, for example, as shown, a first connector 32 and the handpiece 2 a second connector 22 which is designed to connect with the first connector 32 when the handpiece 2 is received on the cradle 3, this connection enabling the handpiece 2 to be charged. The connectors 22 and 32 may be connectors at least one of which is spring- loaded.

[0296] As a variant, the handpiece 2 may be charged by induction when received in the cradle 3.

[0297] The battery 18 may also be removed and charged separately.

[0298] Process for exfoliating the skin K

[0299] The device 1 may be used for exfoliating the skin K.

[0300] The treatment head 5 is thus brought into proximity with the skin K by the user manipulating the handpiece 2, and this user may switch the device 1 on while the treatment head is pressed against the skin K.

[0301] Preferably, the acoustic waves are emitted without the sonotrode emission surface coming into contact with the area to be treated. The grille 20 makes it possible to maintain a minimum distance between the acoustic wave emission surface 10 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. The composition C coming from the reservoir 7 then circulates in the circuit 6, being driven by the pump 11. The composition C is released in contact with the skin.

[0302] The cosmetic composition C preferably comprises a concentration by mass of surfactants of less than or equal to 1%.

[0303] The transducer 13 generates acoustic waves enabling the formation of bubbles within the cosmetic composition C and bursting of said bubbles, thus enabling the desired exfoliation of the skin.

[0304] The frequency of the acoustic waves is preferably between 30 kHz and 45 kHz. Such a frequency allows both the generation and satisfactory bursting of the bubbles in the composition C, and only bursting of any bubbles already present in the medium in the composition.

[0305] The electrical signal exciting the transducer 13 may be pulsed, with a pulse duration preferably of between 0.01 s and 0.09 s, in particular equal to 0.03 s or 0.08 s. The cyclic ratio, when the signal is pulsed, is preferably between 30% and 80%, notably equal to 50%.

[0306] The acoustic intensity Isata of the acoustic waves on the surface of the skin K to be treated is preferably between 0.3 W / cm2and 10 W / cm2, better still between 3 W / cm2and 4 W / cm2, notably equal to 3.18 W / cm2or 3.50 W / cm2.

[0307] The control unit 19 may start the pump 11 and the emission of the acoustic waves only when the area to be treated is in contact with the grille 20, notably in such a way as to allow the composition to be recycled.

[0308] The composition C is, at least partially, reinjected into the circuit 6, notably by virtue of a suction pump 30. The composition C then re-enters the treatment head 5 so as to be sent to a treatment and purification unit 40.

[0309] On leaving the treatment and purification unit 40, the composition C is sent back to the reservoir 7.

[0310] During use of the device 1, the handpiece is moved by the user with a translational and / or rotational movement relative to the surface of the skin K to be treated.

[0311] During use of the device 1, the user preferably manipulates the handpiece 2 in such a way that a skin surface area measuring 5.309 mm2is exfoliated for a time of between 1 s and 60 s, better still for a time of between 7 s and 20 s. The surface 10 is preferably moved relative to the skin at an average sweeping speed of between 7 cm2 / s and 9.9 cm2 / s for the duration of treatment.

[0312] Comparative examples

[0313] Figure 7 shows the performance of various exfoliation techniques. The graph shows the quantity of proteins released by the corneocytes tom from the skin under various conditions.

[0314] The various exfoliation conditions, tested on similar skin samples, are as follows:

[0315] Cl (non-in vention): a transparent adhesive disk is stuck to and kept on the surface of the skin for 5 s with a weight of 2 kg then detached; it removes all of the corneocytes;

[0316] C2 (non-in vention): 100 mg of a scrubbing solution for the skin purchased commercially is applied by rotational motions on the skin using the finger for 7s;

[0317] C3 (non-in vention): 0.5 mL of a peeling solution comprising 30% glycolic acid is applied by rotational motions on the skin using the finger for 7s, then left to rest for 20 min;

[0318] 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 device 1 for treating the skin, without the grille 20, described above, for approximately 7 s, passing over the skin sample five times, with a sweeping speed of approximately 7 cm2 / s;

[0319] 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 device 1 for treating the skin, without the grille 20, described above, for 30 s, passing over the skin sample approximately twenty times, with a sweeping speed of approximately 10 cm2 / s;

[0320] C6 (non-in vention): a quantity of 1.5 mL of the peeling solution is applied to the skin in combination with ultrasonic waves emitted by the device 1 for treating the skin, without the grille 20, described above, for approximately 7 s, passing over the skin sample five times, with a sweeping speed of approximately 7 cm2 / s;

[0321] 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 device 1 for treating the skin, with the grille 20, described above, for approximately 7 s, passing over the skin sample five times, with a sweeping speed of approximately 7 cm2 / s;

[0322] 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 emitted by the device 1 for treating the skin, with the grille 20, described above, for 30 s, passing over the skin sample approximately twenty times, with a sweeping speed of approximately 10 cm2 / s;

[0323] C9 (non-in vention): a quantity of 1.5 mL of the peeling solution is applied to the skin in combination with ultrasonic waves emitted by the device 1 for treating the skin, with the grille 20, described above, for approximately 7 s, passing over the skin sample five times, with a sweeping speed of approximately 7 cm2 / s;

[0324] CIO (non-in vention): 0.25 mL of the cosmetic composition is applied to the skin in combination with a commercially available electric cleansing brush, passing over the skin sample five times;

[0325] Cl 1 (non-in vention): 0.5 mL of the peeling solution is applied to the skin in combination with the cleansing brush, passing over the skin sample five times;

[0326] C12 (non-in vention): 0.25 mL of a gel designed for use with the cleansing brush is applied to the skin in combination with the brush, passing over the skin sample five times.

[0327] As can be seen in figure 7, the results obtained with the scrubbing solution (C2) are on average slightly better than those obtained with the ultrasound combined with the grille and the cosmetic composition (C7 and C8). Without the grille 20, the results obtained with the ultrasound are not quite as good but equivalent to those obtained with the brush combined with gel. The peeling solution alone (C3) is more effective than when it is used with ultrasound (C6 and C9) or the brush (C12).

[0328] To allow effective cleansing, the brush must be used with the associated gel, which has a high content of surfactants (9%). Combined with the cosmetic composition and with the peeling solution (CIO and C12), the brush is the least effective technology.

[0329] Lastly, for the process according to the invention, the following was found:

[0330] - the use of the grille improves the removal of corneocytes (C7 > C4; C8 > C5 and C9 > C6);

[0331] - with or without the grille, a longer exfoliation time (30 s) gives better results (C5 > C4 and C8 > C7).

[0332] The peeling solution with 30% glycolic acid has little effect on the stratum corneum, whether it is used alone or in combination with ultrasound.

[0333] The use of ultrasound with the grille for 30 seconds, combined with the cosmetic composition, gives results equivalent to those obtained with a commercial scrubbing solution (mechanical scrubbing). The use of ultrasound with the grille combined with the cosmetic composition gives better results than obtained using the brush with the associated gel (9% surfactants), with 9 times less surfactants.

[0334] The ultrasound combined with the grille improve the performance of the products (even with a low concentration of surfactants) thanks to synergy between ultrasonic action and mechanical action.

[0335] The treatment device 1 shown in figures 1 to 4 may also be a device for preparing the skin K, designed to implement the process according to the invention, comprising a handpiece 2 and a cradle 3.

[0336] In this case, the reservoir 7 may be designed to deliver the first composition manually or with motorized delivery.

[0337] The battery 18 may be removable; it may be used for powering the entirety of the device 1, or just part, notably the pump 11 and / or the reservoir 7. The battery 18 may be of varying type, for example Li-ion or NiMH, preferably of a type suited to wet conditions or which can be at least partially immersed in a liquid. The battery 18 is preferably rechargeable. The battery 18 is preferably selected to be able, without needing to be recharged, to power the device 1 for a number of consecutive exfoliation sessions, or even several exfoliation sessions and one cleaning of the device 1.

[0338] The cradle 3 may also accommodate secondary or additional reservoirs containing other cosmetic compositions and / or a supplement to the first composition and / or a product for cleaning internal parts of the device.

[0339] The device is for example charged via a USB port (not depicted) notably sited on the cradle 3. The cradle 3 comprises, for example, as shown, a first connector 32 and the handpiece 2 a second connector 22 which is designed to connect with the first connector 32 when the handpiece 2 is received on the cradle 3, this connection enabling the handpiece 2 to be charged. The connectors 22 and 32 may be connectors at least one of which is spring- loaded.

[0340] As a variant, the device may be charged by induction or by photovoltaic components.

[0341] Process for preparing and treating the skin K

[0342] The device 1 may be used for preparing the skin K to receive treatment.

[0343] In a first step of the process, the treatment head 5 is thus brought into proximity with the skin K by the user manipulating the handpiece 2, and this user may switch the device 1 on while the treatment head is pressed against the skin K.

[0344] Preferably, the acoustic waves are emitted without the sonotrode emission surface coming into contact with the area to be treated. The grille 20 makes it possible to maintain a minimum distance between the acoustic wave emission surface 10 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.

[0345] The composition C coming from the reservoir 7 then circulates in the circuit 6, being driven by the pump 11. The composition C is released in contact with the skin.

[0346] The cosmetic composition C preferably comprises a concentration by mass of surfactants of less than or equal to 1%, and / or an active agent referred to as a peeling agent, selected from fruit acids, hydrochloric acid, citric acid, acetic acid, keratolytic compounds, in particular salicylic acid. The transducer 13 generates acoustic waves enabling the formation of bubbles within the cosmetic composition C and bursting of said bubbles, thus enabling the desired exfoliation of the skin.

[0347] The frequency of the acoustic waves is preferably between 30 kHz and 45 kHz. Such a frequency allows both the generation and satisfactory bursting of the bubbles in the composition C, and only bursting of any bubbles already present in the medium in the composition.

[0348] The electrical signal exciting the transducer 13 may be pulsed, with a pulse duration preferably of between 0.01 s and 0.09 s, in particular equal to 0.03 s or 0.08 s. The cyclic ratio, when the signal is pulsed, is preferably between 30% and 80%, notably equal to 50%.

[0349] The acoustic intensity Isata of the acoustic waves on the surface of the skin K to be treated is preferably between 3 W / cm2and 4 W / cm2.

[0350] The control unit 19 may start the pump 11 and the emission of the acoustic waves only when the area to be treated is in contact with the grille 20, notably in such a way as to allow the composition to be recycled.

[0351] The composition C is, at least partially, reinjected into the circuit 6, notably by virtue of a suction pump 30. The composition C then re-enters the treatment head 5 so as to be sent to a treatment and purification unit 40.

[0352] On leaving the treatment and purification unit 40, the composition C is sent back to the reservoir 7.

[0353] During use of the device 1, the handpiece is moved by the user with a translational and / or rotational movement relative to the surface of the skin K to be treated.

[0354] During use of the device 1, the user preferably manipulates the handpiece 2 in such a way that a skin surface area measuring 5.309 mm2is exfoliated for a time of between 1 s and 60 s, better still for a time of between 7 s and 20 s.

[0355] The surface 10 is preferably moved relative to the skin at an average sweeping speed of between 5 cm2 / s and 10 cm2 / s for the duration of treatment.

[0356] In a second step of the process, a cosmetic treatment composition is applied to the skin K, prepared in the first step to receive this composition.

[0357] The second cosmetic composition comprises for example at least one active agent selected from moisturizers, desquamating agents, humectants, anti-aging agents, mattifying agents, cicatrizing agents, antibacterial agents, vitamins and derivatives or precursors thereof, antioxidants, sunscreens, free-radical scavengers; anti-pollutants; selftanning agents; anti-glycation agents; calmatives; deodorant agents; essential oils; NO- synthase inhibitors; agents for stimulating the synthesis of dermal or epidermal macromolecules and / or for preventing degradation thereof; agents for stimulating fibroblast proliferation; agents for stimulating keratinocyte proliferation; muscle relaxants; refreshing agents; tensioning agents; depigmenting agents; propigmenting agents; keratolytic agents; thinning agents; agents which act on cell energy metabolism; insect repellents; substance P antagonists or CRGP antagonists; agents for preventing hair loss; and mixtures thereof.

[0358] Comparative examples

[0359] Figures 9A to 9D show the performance in terms of absorption of a cosmetic product by the skin after various skin pretreatment techniques. The graphs in figures 9 A to 9D show the percentage absorption of four different active agents (A, B, C and D) in various strata of the skin (ST, EP, D and LR), after various pretreatment conditions.

[0360] The four active agents (A, B, C and D) are active agents commonly found in cosmetic compositions; for example active agent A is caffeine and active agent C is Minoxidil.

[0361] Figure 6 shows the strata of the skin in question: the stratum corneum (ST), the epidermis (EP), the dermis (D) and the receptor liquid (LR).

[0362] The various pretreatment conditions, tested on similar skin samples, are as follows:

[0363] Cl (non-in vention): a quantity of 0.5 mL of a scrubbing solution for the skin with a pH of 1.2 and comprising 10% glycolic acid is applied to the skin for 20 min, then the skin is dried;

[0364] C2 (non-in vention): a quantity of 0.25 mL of a commercial composition comprising surfactants is applied to the skin in combination with a commercially available electric cleansing brush, for 5 seconds, then the skin is rinsed and dried;

[0365] C3 (non-in vention): no pretreatment performed, the skin is dried;

[0366] C4 (non-in vention): the stratum corneum is entirely removed using adhesive strips, then the skin is dried; C5 (example according to the invention): a quantity of 1.5 mL of a foaming cosmetic composition comprising 1% surfactants is applied in combination with ultrasonic waves emitted by the device 1 for treating the skin, with the grille 20, described above, for approximately 30 s, then the skin is rinsed and dried;

[0367] C6 (example according to the invention): a quantity of 1.5 mL of the scrubbing solution for the skin with a pH of 1.2, comprising 10% glycolic acid, is applied in combination with ultrasonic waves emitted by the device 1 for treating the skin, with the grille 20, described above, for approximately 30 s, then the skin is dried;

[0368] C7 (non-in vention): a quantity of 1.5 mL of a cosmetic composition comprising the four active agents described above is applied in combination with ultrasonic waves emitted by the device 1 for treating the skin, with the grille 20, described above, for approximately 30 s, then the skin is dried; this is a co-treatment.

[0369] For each of these conditions Cl to C6, the pretreatment is followed by the application of 10 mg of the cosmetic composition comprising the four active agents described above, then the skin is washed after one hour of application.

[0370] As can be seen in figures 9A to 9D, when the device is used under the pretreatment condition (C5), preparation of the skin combining the device with the foaming cosmetic composition, it allows an increase in cutaneous absorption of active agents A and B compared to conventional topical application (C3) or the use of the electric cleansing brush (C2).

[0371] However, when the device is used directly with the cosmetic composition comprising the active agents, co-treatment (C7), this does not allow an increase in cutaneous absorption.

[0372] As regards scrubbing (Cl), used alone with topical application for 20 min, it performs with regard to the condition of conventional topical application (C3).

[0373] After 30 seconds of pretreatment combining the device and scrubbing (C6), an increase an absorption can be seen compared to conventional topical application (C3). These results show that the use of cavitation in combination with a first cosmetic cleansing composition, in particular foaming, promotes the action of active agents contained in the second composition subsequently applied, in particular their absorption by the skin.

[0374] Needless to say, the invention is not limited to the examples that have just been described.

[0375] It is possible for the handpiece to comprise just one single pump which circulates the fluid in the exfoliation area and returns it to a reservoir intended to recover the used fluid.

Claims

Claims1. A cosmetic, and non-therapeutic, process for exfoliating the skin, including the scalp, and / or the nails, comprising the step consisting in subjecting a surface of said skin (K), or 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 in the region exposed to the acoustic waves that is at least equal to 0.1 W / cm2, i) the transducer (13) being moved relative to said surface (K) at an average sweeping speed of between 0.01 cm2 / s and 15 cm2 / s for the duration of treatment of said surface, and / or ii) the device (1) being applied to a location on the keratin material (K), then moved away from the latter and applied to a different location.

2. The process as claimed in claim 1, the energy delivered by the device (1) onto said surface (K) being between 0.1 J / cm2and 15 J / cm2.

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

4. The process as claimed in either of claims 1 and 2, the cosmetic composition (C) containing at least one surfactant, the concentration by mass of surfactant(s) being between 0.1% and 1.5%.

5. The process as claimed in 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 different from the abovementioned polyoxyalkylenated alkyl(amido) ether carboxylic acids, nonionic surfactants, amphoteric and zwitterionic surfactants, and mixtures thereof, and / or chosen from the compounds conventionally present in makeup-removing compositions such as alkylpolysaccharides, fatty alcohol polyethylene glycols, oils, and mixtures thereof.

6. The process as claimed in any one of the preceding claims, being performed on naked skin (K).

7. The process as claimed in any one of the preceding claims, the device (1) emitting the ultrasonic acoustic waves comprising a grille (20) defining a surface for contact with the skin (K) to be treated, the grille (20) having at least one opening (300) through which the waves emitted by the transducer (13) may propagate toward the skin (K) to be treated, the process comprising the step consisting in exposing said surface (K) to acoustic waves while it is at least partially in contact with the grille (20).

8. The process as claimed in the preceding claim, the grille (20) having a ratio of the total surface area of the openings (300) relative to the surface area for contact of greater than or equal to 0.3, better still 0.8.

9. The process as claimed in any one of the preceding claims, comprising passing the device (1), in particular vertically from top to bottom in the case of the facial skin, one or more times over said surface (K) during exfoliation.

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

11. The process as claimed in any one of the preceding claims, the transducer (13) being moving for the whole duration of the treatment, or if not, static relative to said surface (K) for a duration not exceeding 0.5 s, better still 1 s.

12. The process as claimed in 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 / cm2during exfoliation, this contact pressure being in particular the pressure of the grille (20) on the skin (K), or the pressure of another element of the device (1) in contact with the skin (K), in particular a non- smooth or rough element.

13. The process as claimed in any one of the preceding claims, the only bubbles of air present in the composition (C) being those generated by the acoustic waves,14. The process as claimed in any one of the preceding claims, the cosmetic composition (C) being applied continuously to said surface (K) during exfoliation.

15. The process as claimed in any one of the preceding claims, the cosmetic composition (C) placed in contact with the skin (K) during exfoliation being at least partially recovered and / or recycled.

16. The process as claimed in any one of the preceding claims, the acoustic waves having at least one frequency component between 30 and 55 kHz.

17. The process as claimed in any one of the claims, the electrical supply of the transducer (13) being pulsed, the cyclic ratio 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 for which the transducer (13) is supplied with power during a cycle and Toff the duration for which it is switched off.

18. The process as claimed in any one of the preceding claims, the distance between the acoustic wave emission surface (10) 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. The process as claimed in any one of the preceding claims, the sweeping speed being between 5 and 15 cm2 / s.

20. The process as claimed in any one of the preceding claims, the exfoliation corresponding to a dose of proteins of at least 0.4 micrograms in the dead skin removed per cm2of skin treated.

21. A process for preparing and treating human keratin material (K), in particular the skin or the scalp, comprising the steps consisting in:(a) pretreating a surface of said keratin material (K) by subjecting it to a first 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 in the region exposed to the acoustic waves that is at least equal to 0.1 W / cm2, i) the transducer (13) being moved relative to said surface at an average sweeping speed of between 0.01 cm2 / s and 15 cm2 / s for the duration of treatment of said surface, and / or ii) the device (1) being applied to a location on the keratin material (K), then moved away from the latter and applied to a different location, and(b) applying a second cosmetic composition to said surface of the keratin material (K).

22. The process as claimed in claim 21, comprising only the method of application of step i).

23. The process as claimed in claim 21, comprising only the method of application of step ii).

24. The process as claimed in claim 21, comprising both the method of application of step i) and the method of application of step ii).

25. The process as claimed in any one of claims 20 to 24, the keratin material (K) treated being the skin.

26. The process as claimed in any one of claims 20 to 25, the first cosmetic composition (C) containing at least one surfactant, preferably with a total concentration by mass of surfactant(s) in the composition of less than or equal to 3%, better still less than or equal to 1%.

27. The process as claimed in any one of claims 20 to 26, the first composition (C) comprising at least one surfactant chosen from foaming surfactants such as polyoxy alky lenated alkyl(amido) ether carboxylic acid anionic surfactants, anionic surfactants different from the abovementioned polyoxyalkylenated alkyl(amido) ether carboxylic acids, nonionic surfactants, amphoteric and zwitterionic surfactants, and mixturesthereof, and / or chosen from the compounds conventionally present in makeup-removing compositions such as alkylpolysaccharides, fatty alcohol polyethylene glycols, oils, and mixtures thereof.

28. The process as claimed in any one of claims 20 to 27, the first composition (C) comprising at least one active agent selected from fruit acids, hydrochloric acid, citric acid, acetic acid, keratolytic compounds, in particular salicylic acid.

29. The process as claimed in any one of claims 20 to 28, step (a) being performed on naked skin.

30. The process as claimed in any one of claims 20 to 29, step (a) comprising passing the device (1), in particular vertically from top to bottom in the case of the facial skin, one or more times over said surface (K).

31. The process as claimed in any one of claims 20 to 30, the transducer (13) being moved in step (a) with a translational and / or rotational movement relative to said surface (K).

32. The process as claimed in any one of claims 20 to 31, the transducer (13) being moving for the whole duration of the treatment of step (a), or if not, static relative to said surface (K) for a duration not exceeding 0.5 s, better still 1 s.

33. The process as claimed in any one of claims 20 to 32, the first cosmetic composition (C) being applied continuously to said surface (K) in step (a).

34. The process as claimed in any one of claims 20 to 33, the first cosmetic composition (C) placed in contact with the skin (K) during step (a) being at least partially recovered and / or recycled, or the first cosmetic composition (C) not being refreshed in the area subjected to the acoustic waves during step (a).

35. The process as claimed in any one of claims 20 to 34, the energy delivered by the device (1) onto said surface (K) in step (a) being between 0.1 J / cm2and 15 J / cm2.

36. The process as claimed in any one of claims 20 to 35, the acoustic waves emitted in step (a) having at least one frequency component between 30 and 55 kHz.

37. The process as claimed in any one of claims 20 to 36, the electrical supply of the transducer (13) in step (a) being pulsed or not pulsed, the cyclic ratio Ton / Toff when the signal is pulsed being between 1% and 99%, better still between 10% and 90%, and / or the pulse duration Ton being between 0.01 s and 0.09 s Ton designating the duration for which the transducer (13) is supplied with power during a cycle and Toff the duration for which it is switched off.

38. The process as claimed in any one of claims 20 to 37, the distance between the acoustic wave emission surface (10) of the transducer (13) and said surface (K) to be treated in step (a) being between 0.1 mm and 30 mm when the surface is exposed to the acoustic waves.

39. The process as claimed in any one of claims 20 to 38, the speed of sweeping of the surface by the transducer (13), in step (a), being between 5 and 15 cm2 / s.

40. The process as claimed in any one of claims 20 to 39, the second cosmetic composition comprising at least one cosmetic active agent selected from moisturizers, desquamating agents, humectants, anti-aging agents, mattifying agents, cicatrizing agents, antibacterial agents, vitamins and derivatives or precursors thereof, antioxidants, sunscreens, free-radical scavengers; anti-pollutants; self-tanning agents; antiglycation agents; calmatives; deodorant agents; essential oils; NO-synthase inhibitors; agents for stimulating the synthesis of dermal or epidermal macromolecules and / or for preventing degradation thereof; agents for stimulating fibroblast proliferation; agents for stimulating keratinocyte proliferation; muscle relaxants; refreshing agents; tensioning agents; depigmenting agents; propigmenting agents; keratolytic agents; thinning agents; agents which act on cell energy metabolism; insect repellents; substance P antagonists or CRGP antagonists; agents for preventing hair loss; and mixtures thereof.

41. The process as claimed in any one of claims 20 to 40, the second composition being applied in step b) as soon as the treatment of step a) is finished, or as a variant, a little later, preferably less than 5 min after the end of step a).

42. The process as claimed in any one of claims 20 to 41, including a step consisting in rinsing said surface of the keratin material (K), between step (a) and step (b).

43. The process as claimed in any one of claims 20 to 42, including a step of pretreatment of said surface of the keratin material (K), upstream of step (a).

44. Treatment assembly for performing the process as claimed in any one of claims 20 to 43, comprising, in particular within the same packaging: the first cosmetic composition comprising a surfactant and / or an active agent selected from fruit acids, hydrochloric acid, citric acid, acetic acid, keratolytic compounds, in particular salicylic acid, - a device for exposing the first cosmetic composition to acoustic waves in the vicinity of the surface to be prepared, and the second cosmetic composition for treating said surface.

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