Process for the preparation and treatment of keratinous materials

Abstract

Method for preparing and treating keratinous materials. A method for preparing and treating human keratinous materials, including skin or scalp, comprising the steps of: (a) pretreating a surface of said keratinous materials 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 at the level of the region exposed to the acoustic waves of at least 0.1 W / cm², (i) the transducer being moved relative to said surface at an average scanning speed of between 0.01 cm² / s and 15 cm² / s during the time of treatment of said surface, and / or (ii) the device being applied in one location on the keratinous materials, then moved away from them and applied in a different location, and (b) applying a second cosmetic composition to said surface of the keratinous materials.Figure for the abridged version: Fig. 1.

Description

Title of the invention: Process for the preparation and treatment of keratin materials Technical field

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

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

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

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

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

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

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

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

[0009] There is a need to improve the effectiveness of a treatment using a cosmetic product applied to keratin materials, for example to allow, with constant effectiveness, to reduce the quantity of active ingredient by facilitating its action, or with equal quantity, to increase its action. Summary of the invention

[0010] The invention aims to meet this need and thus has as its subject, according to a first of its aspects, a process for preparing and treating human keratin materials, in particular the skin or scalp, comprising the steps of: (a) pretreating a surface of said keratin materials 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 at the region exposed to the acoustic waves at least equal to 0.1 W / cm2, i) the transducer being moved relative to said surface at an average scanning speed of between 0.01 cm2 / s and 15 cm2 / s during the treatment time of said surface, and / or (ii) the device being applied to one location on the keratin materials, then moved away from them and applied to a different location, and (b) applying a second cosmetic composition to said surface of the keratin materials.

[0011] The method of application of step ii) corresponds to what is called a “tapping” movement, where the device is applied to the keratin materials by a succession of movements of bringing said materials closer and further apart, shifting it each time. There may be a greater or lesser overlap of the treated area between two successive contacts; for example, between 10 and 90% of the area treated during one contact may be treated during the following contact.

[0012] The method of application of step i) can be carried out without loss of contact of the device with the keratin materials.

[0013] The method may comprise only the mode of application of step i). Alternatively, the method comprises only the mode of application of step ii).

[0014] It is also possible to have a hybrid operation, combining tapping and scanning in contact with said materials, that is to say that when the device comes into contact with said materials the device is moved into contact with them and phases of contact of the device with said materials are alternated with phases of shifting of the device without contact with said materials. The method can therefore comprise both the application mode of step i) and that of step ii).

[0015] In this way, in step (a), bubbles can be generated within the first cosmetic composition in the vicinity of the surface of the keratin materials to be treated and caused to collapse, which is accompanied by a shock wave. This makes it possible to prepare the keratin materials for better and faster absorption of the second composition by them.

[0016] The choice of acoustic intensity and speed ensures a good compromise between comfort of use and the efficiency of the preparation of said keratin materials.

[0017] The method according to the invention is in particular implemented as a cosmetic method for non-therapeutic purposes in order to improve the effects of any type of treatment allowing the improvement of the surface of keratin materials but also of their biology.

[0018] By "cosmetic composition" is meant a composition containing at least one cosmetic active ingredient, as defined in the Cosmetics Directive 76 / 768 / EEC. According to the invention, mineral or tap water does not constitute a cosmetic composition.

[0019] The preparation and treatment can in particular be carried out on the superficial layers of the skin. The area of ​​skin which is prepared and treated according to the invention can be the skin of the face, the bust, the back, the arms, the legs, the hands and / or the feet, the scalp, the nails. The method according to the invention is particularly suitable for the preparation and treatment of the skin of the face, in particular the forehead, the cheeks, the chin, the neck, the nose, the scalp.

[0020] Step (a) according to the invention makes it possible in particular to effectively eliminate or treat impurities, in particular endogenous impurities and / or exogenous impurities, and step (a) consists, for example, of exfoliation of the keratin materials.

[0021] Endogenous impurities include dead cells, dead skin, dandruff, excess sebum, sweat, blackheads. Exogenous impurities include makeup, environmental pollution, dust, microorganisms, or any type of preparation.

[0022] Thus, the treated surface is more receptive to the second composition which is applied in step b) and the method can improve the absorption of the active ingredient(s) contained in the second composition. The treated surface is also more receptive to the first composition.

[0023] 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 materials to be prepared.

[0024] By "complete cavitation" is meant here both the generation and the collapse of bubbles causing a mechanical shock on the surrounding surfaces. The first cosmetic composition may, or may not, have bubbles already present within it before the application of the acoustic waves. The first composition may also comprise a gas dissolved therein, for example carbon dioxide, nitrogen, oxygen, or any gas capable of solubilizing in the composition. The first composition may comprise cosmetic active ingredients capable of penetrating the keratin materials and / or participating in the preparation of the keratin materials with the bubbles.

[0025] The bubbles generated and / or present may also contribute to the release of chemical species contributing to the preparation of keratin materials, such as free radicals.

[0026] The scanning speed corresponds to the surface area per unit time arriving in the area below the surface of emission of acoustic waves and not previously there. First cosmetic composition

[0027] Preferably, the first cosmetic composition contains at least one surfactant, in particular with a total mass concentration of surfactant(s) in the first composition of less than or equal to 3%, or even less than or equal to 1%.

[0028] The surfactant(s) contribute in particular to the suspension of impurities by the formation of micelles, and thus contribute to their elimination.

[0029] A relatively low total level 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 irritations and allergies.

[0030] The first cosmetic composition preferably has a total mass concentration of surfactant(s) of between 0.01% and 20% by weight relative to the total mass of the composition, better still between 0.01% and 5%, even better still 0.01% and 1.5%, even better still between 0.01% and 1%.

[0031] The surfactants may contribute to the formation of bubbles and / or to their stabilization, being for example chosen from foaming surfactants such as polyoxyalkylenated alkyl(amido) ether carboxylic acid anionic surfactants, anionic surfactants other than the aforementioned polyoxyalkylenated alkyl(amido) ether carboxylic acids, non-ionic surfactants, amphoteric and zwitterionic surfactants, and mixtures thereof and / or are chosen from compounds conventionally present in makeup remover compositions such as alkylpolysaccharides, fatty alcohol polyethylene glycols, oils, and mixtures thereof. Any surfactant capable of generating micelles in the medium may be used.

[0032] The first composition may comprise at least one so-called “peeling” active ingredient chosen from acids, in particular fruit acids, strong acids, in particular hydrochloric acid, weak acids, in particular citric acid, acetic acid, keratolytic compounds, in particular salicylic acid. This active ingredient may be in a mass concentration of between 0.01% and 10% by mass, for example.

[0033] The first cosmetic composition sent into contact with the keratin materials can be at least partially recovered and / or recycled.

[0034] The first cosmetic composition can be applied continuously, that is to say that a circulation of the composition is established in contact with the keratin materials, this circulation being for example in a closed or open circuit.

[0035] The first composition may generally comprise any compound conventionally included in the formulation of compositions for cleaning and / or caring for human keratin materials, compatible with the generation of sufficiently large bubbles stable during the application of acoustic waves. Second cosmetic composition

[0036] The second cosmetic composition may comprise all the constituents usually used in the topical application and administration envisaged.

[0037] 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 which may be used in a composition in accordance with the invention, mention may in particular be made of lower monoalcohols having from 1 to 5 carbon atoms such as ethanol and isopropanol, C2-C32 polyols, C3 and C4 ketones and C2-C4 aldehydes.

[0038] The second cosmetic composition may comprise at least one fatty phase, in particular an oily phase. The fatty phase may in particular comprise oils, waxes or pasty fatty substances. Preferably, the fatty phase comprises at least one oil, in particular a cosmetic oil. For example, the fatty phase may comprise at least hydrocarbon, silicone, fluorinated or non-fluorinated oils, or mixtures thereof. The oils may be volatile or non-volatile.

[0039] The second cosmetic composition may be aqueous, and / or comprise hydrophilic active agents.

[0040] The second cosmetic composition may be anhydrous, for example an oil or a balm, and / or contain lipophilic active ingredients.

[0041] The second cosmetic composition may comprise at least one usual cosmetic ingredient which may be chosen in particular from sunscreens, gelling agents and thickeners, hydrophilic or lipophilic cosmetic active ingredients, coloring materials, fillers, dispersing agents, surfactants, and mixtures thereof.

[0042] As cosmetic active ingredients, mention may be made, for example, of moisturizing agents, desquamating agents, humectants, anti-aging agents, mattifying agents, healing agents, anti-bacterial agents, vitamins and their derivatives or precursors, antioxidant compounds, sunscreens, anti-free radical agents, anti-polluting agents, self-tanning agents, anti-glycation agents, soothing agents, deodorant agents, essential oils, NO-synthase inhibitors, agents stimulating the synthesis of dermal or epidermal macromolecules and / or preventing their degradation, agents stimulating the proliferation of fibroblasts, agents stimulating the proliferation of keratinocytes, muscle relaxants, refreshing agents, tightening agents, depigmenting agents, propigmenting agents, keratolytic agents, slimming agents, agents acting on the energy metabolism of cells,insect repellents, substance P or CRGP antagonists, anti-hair loss agents, and their , mixtures.

[0043] The second cosmetic composition may further comprise at least one adjuvant customary in the cosmetic field chosen from perfumes, film-forming polymers, pH adjusters (acids or bases), for example citric acid, tartaric acid or oxalic acid, chelating agents, preservatives, softeners, sweeteners, anti-foaming agents, trace elements, propellants, and mixtures thereof.

[0044] Of course, a person skilled in the art will take care to choose the compound(s) and / or their quantity in such a way that the advantageous properties of a composition according to the invention are not, or not substantially, altered by the envisaged addition.

[0045] The second composition is preferably suitable for topical application to keratin materials and therefore generally comprises a physiologically acceptable medium, i.e. compatible with keratin materials.

[0046] It is preferably a cosmetically acceptable medium, that is to say which has a pleasant color, odor and feel and does not generate unacceptable discomfort, that is to say tingling, tightness, likely to discourage the user from applying this composition.

[0047] The second cosmetic composition can be prepared according to techniques well known to those skilled in the art.

[0048] It can be presented in any conventional galenic form depending on the applications envisaged and is suitable for topical application, that is to say for application to the surface of the keratin materials considered.

[0049] The second composition may be in the form of an aqueous or hydroalcoholic gel. It may be in the form of an emulsion, simple or complex (O / W, W / O, O / W / O or W / O / W), such as a cream, a milk, or a cream gel. They may also be in anhydrous form, for example in the form of an oil.

[0050] The second cosmetic composition may, for example, be used as a makeup product. The second cosmetic composition may, for example, be used as a care and / or sun protection product for the face and / or body of liquid to semi-liquid consistency, and have the appearance of a white or colored cream, more or less creamy, an ointment, a milk, a gel-cream, a lotion, a serum, a paste or a mousse. It may optionally be applied to keratin materials in the form of an aerosol. It may also be in solid form, for example in the form of a stick.

[0051] The second cosmetic composition may be in the form of a product for caring for keratinous materials or semi-mucous membranes, such as a protective composition, cosmetic care for the face, for the lips, for the hands, for the feet, for anatomical folds or for the body (for example day cream, cream night, day serum, night serum, makeup remover cream, makeup base, protective or care body milk, after-sun milk, lotion, gel or mousse for skin or scalp care, serum, mask or after-shave composition).

[0052] More particularly, the second cosmetic composition is intended for topical application. Preferably, such a composition is not intended to be rinsed after application.

[0053] The second cosmetic composition may advantageously have a firm and compact feel when taken. It may be thick upon application and then transform, melt and release freshness.

[0054] The second cosmetic composition may alternatively have the form of a care or makeup product for the face and / or body, and be packaged for example in the form of a cream in a pot or a fluid in a tube or in a pump bottle or in a dropper bottle.

[0055] The second cosmetic composition may comprise one or more molecules having a logP of between -0.5 and 15. The logP must be understood as the logarithm of the ratio of the concentrations of the molecule studied in octanol and in water.

[0056] 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

[0057] The acoustic intensity Lata can be defined as the average acoustic power on the surface subjected to the acoustic waves, divided by said surface: I s ata Pmoy IS, the average acoustic power taking into account the duty cycle when the electrical signal supplying the transducer is pulsed.

[0058] The acoustic intensity Lata is preferably between 0.1 and 10 W / cm2, better still between 1 and 5 W / cm2, even better still between 2.5 and 5 W / cm2, even better still between 3 and 4 W / cm2

[0059] The energy delivered by the device on said surface is preferably between 0.1 J / cm2 and 15 J / cm2, better between 0.1 J / cm2 and 10 J / cm2, during the pretreatment step (a).

[0060] The acoustic waves can be generated by a single transducer, or alternatively by at least two transducers.

[0061] The only air bubbles present in the first composition may be those generated by acoustic waves.

[0062] Each transducer comprises one or more electroactive elements for transforming an electric current into mechanical vibrations, this or these electroactive elements being for example based on piezoelectric materials, as detailed below.

[0063] This or these electroactive elements can be coupled to a sonotrode which can be put into mechanical resonance by the electroactive element(s) and serves to define a surface of emission of acoustic waves towards the target surface or volume.

[0064] The acoustic waves can be generated permanently as soon as the treatment device is put into operation, or alternatively can only be generated when certain operating conditions are met, such as for example 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 the area contains dirt.

[0065] Alternatively, the acoustic waves can be generated only when the quantity 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 temperature of first composition or transducer within a given range, or other.

[0066] The surface area for emitting the acoustic waves ranges, for example, from the surface area of ​​a circle with a diameter of 2 mm to a circle with a diameter of 100 mm, better still from the surface area of ​​a circle with a diameter of 5 mm to that of a circle with a diameter of 50 mm, even better still from the surface area of ​​a circle with a diameter of 5 mm to that of a circle with a diameter of 40 mm, in particular the surface area for emitting the acoustic waves is substantially equal to the surface area of ​​a circle with a diameter of 12 mm.

[0067] They can be generated by a sinusoidal or non-sinusoidal electrical signal, or by a signal of more complex shape, for example frequency modulated or amplitude modulated. The acoustic waves are preferably emitted at a single frequency, which can allow them to be focused more precisely in a given area, but alternatively they can be emitted at several different frequencies.

[0068] Said frequency is preferably between 10 and 500 kHz, better between 30 and 100 kHz, in particular between 30 and 55 kHz. The acoustic waves are for example generated by a transducer with a nominal frequency of approximately 34 kHz.

[0069] The supply voltage of the transducer is preferably between 50 mVpp and 500 mVpp, this voltage is preferably amplified between 95 mVpp and 265 mVpp. The supply voltage of the transducer is for example between 130 mVpp and 160 mVpp, amplified between 248 mVpp and 331 mVpp.

[0070] Said frequency associated with said supply voltage allows both the generation and a satisfactory collapse of the bubbles in the first composition, as well as a collapse alone of any bubbles already present in the medium in the first composition.

[0071] The electrical signal exciting the transducer(s) may be pulsed, with a pulse duration preferably between 0.01 s and 0.09 s, in particular equal to 0.03 s or 0.08 s. Alternatively, the electrical signal exciting the transducer(s) is not pulsed.

[0072] The duty cycle Ton / Toff, when the signal is pulsed, is preferably between between 1% and 99%, better between 5% and 95%, better between 10% and 90%, better between 30% and 80%, even better between 50% and 70%, for example approximately equal to 50%, Ton designating the duration during which the transducer is powered during a cycle and Toff the duration during which it is switched off.

[0073] The method may include a step of detecting the presence of the first cosmetic composition in contact with the sonotrode, and conditioning the operation of the transducer on this detection. This detection is done for example by measuring the impedance of the system.

[0074] This avoids the emission of acoustic waves in the absence of a first composition or when the device is not in a situation of treating keratin materials.

[0075] Preferably, the acoustic waves are emitted without the emission surface of the sonotrode coming into contact with the area to be treated. The distance between the transducer and the surface to be treated is for example between 0.1 mm and 30 mm, more particularly between 3 and 5 mm, when the keratin materials are exposed to the acoustic waves, which makes it possible to limit the acoustic energy emitted in the keratin materials, and to promote the cavitation of the bubbles in the first composition.

[0076] The distance between the transducer and the surface to be treated must be understood as the distance between the emission surface of the sonotrode and the surface to be treated.

[0077] The first composition can be circulated continuously in contact with the sonotrode, with continuous operation of the transducer(s), or alternatively, pulsed operation of the transducer(s). The supply of the first composition can also be done in a pulsed manner. Advantageously, a supply of a zone subjected to the acoustic waves is discontinuous, for example with a period of supply of the zone while the acoustic waves are not generated, then a period where the first composition present in the zone is subjected to the acoustic waves without being renewed during this exposure. This can prevent the bubbles present in the first composition before entering said zone from being repelled by the acoustic waves present therein.Alternatively, the first composition may not be renewed in the area subjected to the acoustic waves during step (a), that is to say that in the presence of a supply circuit, the latter no longer delivers composition. The supply of first composition, for its recycling for example, may thus be temporarily interrupted during the exposure of the surface to be treated to the acoustic waves.

[0078] It is thus possible to control the supply of first composition to the exfoliation zone to the operation of the transducer(s) for producing acoustic waves or vice versa, and to have a pulsed operation of the transducer(s) and / or the supply of first composition. In other words, it is possible to carry out a supply of first composition with a time lag compared to the period of emission of acoustic waves in the area of ​​contribution of the first composition.

[0079] The propagation of acoustic waves is facilitated by the presence of liquid in the first composition. The gas / liquid mass ratio within the first composition can thus benefit from not being too high, and the first composition can advantageously contain a thickener, or any other compound making it possible to increase the temporal stability of the bubbles. Abrasion

[0080] The method may comprise abrasion, prior to or simultaneously with the pretreatment step (a), of the keratin materials using abrasive particles and / or by a part of the device in contact with the surface to be treated.

[0081] This abrasion can be carried out 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 grid, a blade, a scraper, granules stuck on the device, such as diamond or silica particles, or any other suitable accessory.

[0082] The part allowing the abrasion to be carried out is for example put in place to carry out the abrasion, then removed at the time of exfoliation by the bubbles and acoustic waves, being for example interchangeable with a part of the device used for exfoliation by the acoustic waves and bubbles.

[0083] The part allowing the abrasion to be carried out may still be present during the exfoliation of the bubbles and acoustic waves, as will be described below. This part may then have the form of a grid, among other possibilities.

[0084] The abrasion may be carried out prior to the exposure of the cosmetic composition and the bubbles to the acoustic waves, or alternatively concomitantly. When the abrasion is prior, it may be carried out by any means, in particular by mechanical or chemical action. Grid

[0085] The ultrasonic transducer preferably belongs to a device further comprising a grid defining a contact surface with said surface to be treated, the grid having at least one opening, preferably at least two openings, through which the waves emitted by the transducer can propagate in the direction of the surface to be treated.

[0086] The method according to the invention may comprise the step of exposing at least part of the surface of the keratin materials to acoustic waves while it is in contact with the grid.

[0087] Thanks to the grid, it is possible to control more precisely the distance between the transducer and the surface to be treated, which makes it possible to improve the action of the bubbles at vicinity of said surface, while avoiding direct contact of the transducer with this surface.

[0088] The grid is preferably non-absorbent, i.e. it is not porous.

[0089] The grid may in particular not have the capacity to soak up water when immersed in water, and retain for example less than 10% of water, better still less than 5% of its water weight. The grid may have undergone a treatment improving its wettability in the first composition.

[0090] The grid can in particular be made from a solid material, therefore different from foam, fabric or felt.

[0091] The contact surface of the device with the keratin materials can be defined by a non-absorbent surface of the grid.

[0092] The region of the grid defining the openings thereof may be defined by a non-absorbent portion of the grid.

[0093] The grid is preferably removable, that is to say it can be easily detached by the user of the device, preferably without using a tool. This facilitates cleaning and allows it to be replaced between uses, or, if desired, to interchange several grids depending on the use, for example by choosing the type of grid best suited to the morphology of the area to be treated.

[0094] The contact surface defined by the grid may be substantially flat, for example in order to maintain a substantially constant distance between the transducer and the surface to be treated located opposite the surface emitting the acoustic waves.

[0095] Alternatively, the grid may define a contact surface adapted to the morphology of the area to be treated, for example of a curved shape.

[0096] The grid may further have, where appropriate, an adjustable effective diameter. The device may comprise a variable aperture mechanical element such as a diaphragm, arranged in front of or behind the grid, so as to adjust the accessible diameter of the opening(s). For example, the device comprises a diaphragm centered on the longitudinal axis of the transducer.

[0097] Some or all of the openings of the grid can be closed in whole or in part in a controlled manner. This makes it possible, depending on the area to be treated, and in particular for more sensitive areas such as those located in the vicinity of the eyes, to limit the surface area and intensity of treatment, if desired. The device may comprise a shutter movable between a position of non-occultation of one or more openings of the grid and a occultation position where the opening(s) are occulted at least partially, or even totally. This shutter is for example adjusted manually by the user as required.

[0098] Preferably, the grid has a thickness of between 0.1 and 10 mm, better still between 0.5 and 5 mm. Thus, a minimum distance of at least this thickness is ensured between the transducer and the surface to be treated, regardless of the position of the grid relative to the transducer.

[0099] The grid may be fixed to a movable or fixed spacer, the spacer being fixed to the device and in particular making it possible to maintain a space between the grid and the surface of the transducer. It may form a chamber with the surface of the transducer or the fixing part from which it projects from the surface of the transducer.

[0100] The grid is preferably formed from a rigid or semi-rigid material, for example metal, or rigid plastic. The grid is for example made from a material chosen from a metal, in particular steel, stainless steel, an alloy, silicone, a polymer, in particular of the polyurethane (PU), polyethylene terephthalate (PET) or polythiophene (PT) type, or a combination of several of these elements.

[0101] The grid may not deform visibly to the naked eye during normal use, due to its rigidity. Alternatively, the grid may be deformable. For example, its diameter may be reduced by applying mechanical pressure to its contour.

[0102] The grid may comprise recesses, in particular extending along its thickness. The grid comprises, for example, deformable channels, the diameter of which may vary depending on the pressure applied, extending, for example, in a non-longitudinal direction. Alternatively, the channels may be rigid in order to allow the passage of fluid even if pressure is applied to the grid. The surface area of ​​the channels may be variable and their shape different, for example round, square, or triangular.

[0103] The grid may still have reliefs or be flocked, or not.

[0104] The grid can be made with reliefs or in an intrinsically rough, in order to have a non-smooth contact surface with keratinous materials. Such a surface condition makes it possible to obtain a mechanical abrasive effect which can participate in exfoliation when the device is moved over the area to be treated during use. The grid may contain several materials of varying abrasiveness, for example a more abrasive material in the center of the grid and a less abrasive material on the edges of the grid, or vice versa.

[0105] The device may comprise a gate drive element configured to generate an oscillating, vibrating and / or rotating movement of the grid. For example, the device comprises a motor for driving the grid into motion, for example rotary, linear, eccentric or other, reciprocating or not. The device may comprise a vibrator, if necessary, to vibrate the grid. The amplitude of the movement may be fixed or adjustable.

[0106] The mechanical abrasive effect can thus be obtained automatically due to the movement imposed by the device on the grid, and the impurities cleaned more efficiently.

[0107] The grid can be made in different ways.

[0108] The grid may comprise a peripheral frame, which defines the outer contour of the grid in front view. This frame may be rigid, in particular more rigid than a central part of the grid, openwork.

[0109] The outline of the grid, in front view, may be circular, oval, polygonal or other in shape, and preferably the grid has a closed outline.

[0110] The opening(s) of the grid may be substantially the same size. The grid may comprise a plurality of openings arranged in a regular array, for example in rows or columns.

[0111] Alternatively, the opening(s) may be arranged concentrically.

[0112] The openings may have various shapes, in particular shapes in the form of portions of disc(s) or ring(s).

[0113] The grid may have a single opening, in particular of non-circular outline, for example in the form of a slot, a cross, a polygon, regular or not, or an oval. Preferably, the grid has at least two openings, in particular two openings having substantially the same size.

[0114] In the presence of a single opening, this may or may not be centered.

[0115] A grid having a fine mesh improves the maintenance of the surface to be treated when using the device, which allows better control of a constant distance between said surface to be treated and the surface of emission of the acoustic waves, and thus of the cavitation phenomenon.

[0116] An opening of the grid may have an area of ​​at least 1 mm2. A smallest dimension of an opening of the grid, in front view, is for example at least 0.5 mm.

[0117] Preferably, the grid has a ratio of the total surface area of ​​the openings relative to the contact surface area of ​​the grid with the keratin materials greater than or equal to 0.3, better still 0.5, even better still 0.8.

[0118] Such a ratio makes it possible to prevent the keratin materials from rising up on contact with the transducer or from becoming deformed, while maintaining enough openings for the ultrasonic waves to reach the area to be treated or its vicinity over a sufficient extent with regard to the desired result.

[0119] Acoustic waves can propagate through at least one or two openings in the grid.

[0120] The grid may be moved during exfoliation, for example intermittently, remaining stationary for a certain period of time, then moved in increments, along the surface to be treated. The grid may still be moved continuously over the surface to be treated. Circulation of the composition in the grid

[0121] The device may further comprise at least one conduit extending into the grid.

[0122] Such a device makes it possible to apply the first cosmetic composition continuously or not, or in an alternating manner with the application of ultrasound, that is to say that a circulation of the first composition is established in contact with the surface to be treated, this circulation being carried out for example in a closed or open circuit.

[0123] When the circulation is established in a closed circuit, the device may comprise at least one return conduit connected to a suction pump, making it possible to recover at least partially the first composition in the vicinity of the surface to be treated, in particular at least one conduit extending into the grid. Process

[0124] The method according to the invention can be carried out on bare skin, on the scalp, on the nails or even on the hair.

[0125] Step (a) of the method may comprise one or more passes of the device, in particular vertically from top to bottom in the case of facial skin, over the surface of the skin. The passage of the device may be carried out over a horizontal surface, in particular in several back-and-forth movements.

[0126] The transducer can be moved in a translational and / or rotational movement relative to said surface.

[0127] The transducer may be mobile throughout the duration of the treatment of step (a), otherwise static relative to said surface for a duration not exceeding 0.5 s, better still 10 seconds.

[0128] The scanning speed of the surface by the transducer, in step (a), can be between 5 and 15 cm2 / s.

[0129] The contact pressure of the device on the skin to be treated may be greater than or equal to 0.1 N / cm2 during step (a).

[0130] The application of the second composition in step b) can take place as soon as the treatment of step a) is finished, or alternatively 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).

[0131] The surface on which the second composition is applied in step b) is preferably dry.

[0132] The application of the second composition in step b) may be carried out by hand or by means of an applicator, or even an applicator forming part of the device used for the treatment in step a). The application of the second composition in step (b) may be carried out with the device via which the first composition is delivered or via another hand-held device, the device applying the second composition possibly being motorized or not. 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 an additional package.

[0133] The method may comprise a step of rinsing said surface of keratin materials between step (a) and step (b). The rinsing of said surface is carried out in particular with water.

[0134] The method may comprise an additional step of pretreatment of said surface of keratin materials, upstream of step (a), in particular a step comprising the application of an additional cosmetic composition to said surface and / or rinsing of said surface.

[0135] An additional step of preparing the skin after step (a) can be carried out before step (b). Treatment kit

[0136] The invention also relates to a treatment assembly (kit) for implementing the method according to the invention, as defined above.

[0137] This set advantageously includes, in particular within the same packaging: - the first cosmetic composition comprising a surfactant and / or an active agent chosen 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 the treatment of said surface.

[0138] The compositions may or may not be packaged with the device in the same packaging. The compositions may be packaged in separate, or secondary, packaging from the device packaging.

[0139] 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 fixed in whole or in part in a corresponding housing of the device, or to be connected to the device by a suitable connection such as a pipe. This container can be used alone in the device to deliver the first composition. Brief description of the drawings

[0140] The invention may be better understood by reading the detailed description which follows, non-limiting examples of its implementation, and by examining the attached drawing, in which:

[0141] [Fig-1] illustrates in a schematic and partial manner, an example of a pre-device preparation of human skin using the method according to the invention,

[0142] [Fig.2] schematically and partially illustrates a handpiece of the device of [Fig.l],

[0143] [Fig.3] illustrates schematically and partially the device of [Fig.l] with a tank separate from the handpiece,

[0144] [Fig.4] illustrates schematically and partially the device of [Fig.l] in the form of a block diagram,

[0145] [Fig.5] illustrates in a partial and schematic manner, a treatment head of the device of [Fig.l] comprising a grid,

[0146] [Fig.6] illustrates the different layers of the skin,

[0147] [Fig.7A] to [Fig.7D] illustrate the absorption performance of a cosmetic composition by the skin after different pretreatment conditions. Detailed description

[0148] Figures 1 to 4 illustrate a device 1 for preparing the skin K, arranged to implement the method according to the invention, comprising a handpiece 2 and a support 3. Handpiece

[0149] The handpiece 2 comprises a handle 4, a treatment head 5, a circuit 6 for the circulation of a composition C and at least one reservoir 7 containing this composition C.

[0150] The reservoir 7 makes it possible, during operation of the device, to compensate for any losses in composition, in the event of non-recycling of part of it.

[0151] The reservoir 7 is preferably separable from the handpiece, as illustrated in [Fig. 3]. Alternatively, the reservoir 7 is not separable from the handpiece.

[0152] The reservoir 7 preferably comprises a wall 15 which is at least partly transparent, allowing a user to determine the level of cosmetic composition present in the reservoir 7.

[0153] The reservoir can be arranged to deliver the first composition manually or by motor.

[0154] The circuit 6 comprises a delivery pump 11, shown schematically in [Fig. 4]. The pump 11 may have any type of drive, in particular manual or electric, preferably electric. It may be of various types. The pump 11 is for example a volumetric or centrifugal pump, in particular peristaltic, diaphragm, piston, or a combination of several types. The pump 11 may be powered by direct or alternating current. Preferably, the supply voltage of the pump 11 is less than 50V, being for example powered at a voltage ranging from 5 to 12V. The pump 11 is preferably compatible with liquids of various types, in particular aqueous, oily, mixed liquids, liquids containing particles or suspended charges, or even polymers. The drive of the mechanism of the pump 11 may be done directly by a motor or in a reduced manner. When the drive is manual, the device 1 may comprise a handle that is operated by the user to operate the pump 11. Preferably, the pump 11 is configured to provide a fluid flow rate between 0.01 mL and 15 mL per second. The pump 11 may be removable, or not. The pump 11 may generate negative and / or positive pressure on the fluid to allow the circulation of the fluid and its contact with the skin. The pump may also be used for internal cleaning of all or part of the device. The pump 11 may contain a filter in one or more parts. The pump 11 may be mechanically or electrically isolated in the device 1, for example to be removed from the device 1 for cleaning.

[0155] The treatment head 5 comprises a surface 10 in contact with the composition C, the treatment head 5 being arranged to deliver the composition C to an area of ​​the skin K to be treated.

[0156] The treatment head 5 comprises at least one transducer 13 emitting acoustic waves and a sonotrode, the surface 10 in contact with the composition being for example defined by a free end of the sonotrode. Bubbles can be generated in the composition C thanks to the acoustic waves due to the power and frequency of the acoustic waves.

[0157] The transducer 13 may be powered by an electrical source with direct or alternating current. The acoustic power delivered by the transducer 13 may vary depending on the supply voltage of the transducer and / or depending on the current supplying the transducer, in particular depending on its direct or alternating state.

[0158] The emission surface 10 of the acoustic waves towards the liquid medium may comprise reliefs or engravings where the bubbles can originate at different levels along the longitudinal axis of the transducer 13. In particular, these reliefs may offer nucleation sites at their top and at their base. The reliefs may allow a more homogeneous production of the bubbles. These reliefs may also promote the collapse of the bubbles, because the differences in levels along the longitudinal axis make it possible to generate relatively extensive cavitation zones, not limited to a single plane. In addition to the reliefs of the emission surface 10 which contribute to improving the production of the bubbles, the emission surface may have reliefs which pursue another purpose, for example exercising an action of retaining the fluid or cleaning the zone to be treated.These are, for example, reliefs made of a flexible material, for example hairs, in particular flocking hairs.

[0159] The handpiece 2 comprises an electronic circuit 14 comprising in particular a control unit 19.

[0160] The control unit 19 controls the operation of the pump 11, of a battery 18 supplying the device (in particular its load), of the transducer 13.

[0161] The control unit 19 is connected by a connector to an electronic generator 16, supplying in particular the transducer 13. This generator 16 comprises for example an oscillator and a power stage.

[0162] The battery 18 may be removable, it may be used to power the entire device 1, or only a part, in particular the pump 11, and / or the reservoir 7. The battery 18 may be of various types, for example Li-ion or NiMH, preferably of a type suitable for humid conditions or which can be immersed in a liquid at least partially. The battery 18 is preferably rechargeable. The battery 18 is preferably selected to ensure, without having to be recharged, the power supply of the device 1 during several consecutive exfoliations, or even several exfoliations and cleaning of the device 1.

[0163] The handpiece 2 may comprise a grid 20 in contact with the skin to be treated, comprising for example regular openings arranged in rows and columns, as shown in [Fig.5]. Support

[0164] The support 3 comprises, as illustrated in [Fig. 3], a first housing 8 for receiving the handpiece 2 and a second housing 9 for receiving the reservoir with an opening of the reservoir 7 facing downwards. The reservoir 7 can be received in the housing 9 of the support, while the handpiece 2 separated from the reservoir 7 is received in the housing 8 of the support 3.

[0165] The support 3 can accommodate other accessories necessary for the operation or recharging of the device. The support 3 can in particular accommodate accessories, such as a brush, a key, a screwdriver, necessary for the disassembly and / or cleaning of internal or removable parts of the device.

[0166] The support 3 can also accommodate secondary or additional reservoirs containing other cosmetic compositions and / or a complement to the first composition and / or a product for cleaning the internal parts of the device.

[0167] The device is for example charged using a USB port (not shown), in particular arranged on the support 3. The support 3 comprises for example, as illustrated, a first connector 32 and the handpiece 2 a second connector 22 arranged to connect to the first connector 32 when the handpiece 2 is received on the support 3, this connection allowing the handpiece 2 to be charged. The connectors 22 and 32 may be connectors of which at least one is spring-loaded.

[0168] Alternatively, the device may be charged by induction or by photovoltaic parts.

[0169] Alternatively, the handpiece 2 can be charged by induction when it is received on the support 3.

[0170] The battery 18 can also be removed and charged separately.

[0171] Process for the preparation and treatment of K skin

[0172] The device 1 can be used for preparing the skin K to receive treatment.

[0173] In a first step of the method, the treatment head 5 is thus brought close to the skin K by the user manipulating the handpiece 2, and the latter can start the device 1 while the treatment head is applied against the skin K.

[0174] Preferably, the acoustic waves are emitted without the emission surface of the sonotrode coming into contact with the area to be treated. The grid 20 makes it possible to maintain a minimum distance between the surface 10 for emitting the acoustic waves and the surface of the skin K to be treated. The distance between the surface 10 and the surface to be treated is for example between 3 mm and 5 mm, in particular equal to 3 mm.

[0175] Composition C from reservoir 7 then circulates in circuit 6 by driving pump 11. Composition C is released on contact with the skin.

[0176] Cosmetic composition C preferably comprises a mass concentration of surfactants less than or equal to 1%, and / or a so-called peeling active ingredient chosen from fruit acids, hydrochloric acid, citric acid, acetic acid, keratolytic compounds, in particular salicylic acid.

[0177] The transducer 13 generates acoustic waves allowing the formation of bubbles within the cosmetic composition C, and their collapse, thus allowing the desired exfoliation of the skin.

[0178] The frequency of the acoustic waves is preferably between 30 kHz and 45 kHz. Such a frequency allows both the generation and satisfactory collapse of the bubbles in composition C, as well as a collapse alone of any bubbles already present in the medium in the composition.

[0179] The electrical signal exciting the transducer 13 may be pulsed with a pulse duration preferably between 0.01 s and 0.09 s, in particular equal to 0.03 s or 0.08 s. The duty cycle, when the signal is pulsed, is preferably between 30% and 80%, in particular equal to 50%.

[0180] The acoustic intensity Isata of the acoustic waves on the surface of the skin K to be treated is preferably between 3 W / cm2 and 4 W / cm2.

[0181] The control unit 19 may only start the pump 11 and the emission of acoustic waves when the area to be treated is in contact with the grid 20, in particular in a manner which allows the composition to be recycled.

[0182] Composition C is reinjected, at least in part, into circuit 6, in particular using a suction pump 30. Composition C then enters treatment head 5 to be sent to a treatment and purification unit 40.

[0183] At the outlet of the treatment and purification unit 40, the composition C is returned in tank 7.

[0184] During use of the device 1, the handpiece is moved by the user in a translational and / or rotational movement relative to the surface of the skin K to be treated.

[0185] During use of the device 1, the user preferably manipulates the handpiece 2, so that a skin surface of 5.309 mm2 is exfoliated for a duration of between 1 s and 60 s, better for a duration of between 7 s and 20 s.

[0186] The surface 10 is preferably moved relative to the skin at an average scanning speed of between 5 cm2 / s and 10 cm2 / s during the treatment period.

[0187] In a second step of the method, a cosmetic treatment composition is applied to the skin K, prepared to receive this composition during the first step.

[0188] The second cosmetic composition comprises, for example, at least one active agent chosen from moisturizing agents, desquamating agents, humectants, anti-aging agents, mattifying agents, healing agents, anti-bacterial agents, vitamins and their derivatives or precursors, antioxidant compounds, sunscreens, anti-free radical agents, anti-polluting agents, self-tanning agents, anti-glycation agents, soothing agents, deodorant agents, essential oils, NO-synthase inhibitors, agents stimulating the synthesis of dermal or epidermal macromolecules and / or preventing their degradation, agents stimulating the proliferation of fibroblasts, agents stimulating the proliferation of keratinocytes, muscle relaxants, refreshing agents, tightening agents, depigmenting agents, pro-pigmenting agents, keratolytic agents, slimming agents,agents acting on the energy metabolism of cells, insect repellents, antagonists of substances P or CRGP, anti-hair loss agents, and mixtures thereof. Comparative examples

[0189] Figures 7A to 7D illustrate the absorption performance of cosmetic product by the skin after different skin pretreatment techniques. The graphs in Figures 7A to 7D represent the absorption percentage of four different active ingredients (A, B, C and D) at different skin strata (ST, EP, D and LR), after different pretreatment conditions.

[0190] The four active ingredients (A, B, C and D) are active ingredients commonly found in cosmetic compositions, for example active ingredient A is caffeine and active ingredient C is Minoxidil.

[0191] [Fig.6] illustrates the skin strata studied: the stratum corneum (ST), the epidermis (EP), the dermis (D) and the receptor fluid (RL).

[0192] The different pretreatment conditions, tested on skin samples si- military, are as follows: - Cl (outside the invention): a quantity of 0.5 mL of a skin scrub solution having a pH of 1.2 and comprising 10% glycolic acid is applied for 20 min to the skin, then the skin is wiped off; - C2 (outside the invention): a quantity of 0.25 mL of a commercial composition comprising surfactants is applied to the skin in combination with a commercial electric cleansing brush, for 5 seconds, then the skin is rinsed and wiped; - C3 (outside the invention): no pretreatment is carried out, the skin is wiped, - C4 (outside the invention): the stratum corneum is completely removed using adhesive strips, then the skin is wiped, - 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 skin treatment device 1 with grid 20, described above, for approximately 30 s, then the skin is rinsed and wiped; - C6 (example according to the invention): a quantity of 1.5 mL of the skin scrub solution of pH 1.2 comprising 10% glycolic acid is applied in combination with ultrasonic waves emitted by the skin treatment device 1 with grid 20, described above, for approximately 30 s, then the skin is wiped; - C7 (outside the invention): a quantity of 1.5 mL of a cosmetic composition comprising the four active ingredients described above is applied in combination with ultrasonic waves emitted by the skin treatment device 1 with grid 20, described above, for approximately 30 s, then the skin is wiped; this is a co-treatment.

[0193] For each of these conditions C1 to C6, the pretreatment is followed by the application of 10 mg of the cosmetic composition comprising the four active ingredients described above, then the skin is washed after one hour of application.

[0194] As can be seen in Figures 7A to 7D, when the device is used in the pretreatment condition (C5), in preparation of the skin by combining the device with the foaming cosmetic composition, it allows an increase in the cutaneous absorption of the active ingredients A and B compared to a conventional topical deposition (C3) or the use of the electric cleansing brush (C2).

[0195] On the other hand, when the device is used directly with the cosmetic composition comprising the active ingredients, in co-treatment (C7), it does not allow an increase in cutaneous absorption.

[0196] As for the scrub (Cl), used alone in topical application for 20 min, it performs against the condition of classic topical application (C3).

[0197] After 30 seconds of pretreatment by combining the device and the scrub (C6) an increase in absorption is noted compared to the classic topical application (C3).

[0198] These results show that the use of cavitation associated with a first cosmetic cleaning composition, in particular foaming, promotes the action of active ingredients contained in the second composition applied subsequently, in particular their absorption by the skin.

[0199] Of course, the invention is not limited to the examples which have just been described.

[0200] The handpiece may have only one pump which ensures the circulation of the fluid in the exfoliation zone, and its return to a reservoir intended to recover the used fluid.

Claims

Claims

1. Process for the preparation and treatment of human keratin materials (K), in particular the skin or the scalp, comprising the steps of: (a) pretreating a surface of said keratin materials (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 I sata at the region exposed to the acoustic waves at least equal to 0.1 W / cm2, i) the transducer (13) being moved relative to said surface at an average scanning speed of between 0.01 cm2 / s and 15 cm2 / s during the treatment time of said surface, and / or ii) the device (1) being applied to one location on the keratin materials (K), then moved away from them and applied to a different location, and (b) applying a second cosmetic composition to said surface of the keratin materials (K).

2. A method according to claim 1, comprising only the mode of application of step i).

3. A method according to claim 1, comprising only the method of applying step ii).

4. A method according to claim 1, comprising both the mode of application of step i) and that of step ii).

5. Method according to any one of the preceding claims, the keratin materials (K) treated being the skin.

6. Method according to any one of the preceding claims, the first cosmetic composition (C) containing at least one surfactant, preferably with a total mass concentration of surfactant(s) in the composition less than or equal to 3%, better still less than or equal to 1%.

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

8. Method according to any one of the preceding claims, the first composition (C) comprising at least one active agent chosen from fruit acids, hydrochloric acid, citric acid, acetic acid, keratolytic compounds, in particular salicylic acid.

9. A method according to any preceding claim, wherein step (a) is performed on bare skin.

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

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

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

13. Method according to any one of the preceding claims, the first cosmetic composition (C) being continuously applied to said surface (K) in step (a).

14. Method according to any one of the preceding claims, the first cosmetic composition (C) sent into contact with the skin (K) during step (a) being at least partially recovered and / or recycled, or the first cosmetic composition (C) not being renewed in the area subjected to the acoustic waves during step (a).

15. Method according to any one of the preceding claims, the energy delivered by the device (1) on said surface (K) in step (a) being between 0.1 J / cm2 and 15 J / cm2.

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

17. A method according to any one of the claims, the power supply to the transducer (13) in step (a) being pulsed or not, the duty cycle Ton / Toff when the signal is pulsed being comprised between 1% and 99%, better between 10% and 90%, and / or the pulse duration Ton being between 0.01 s and 0.09 s, Ton designating the duration during which the transducer (13) is powered during a cycle and Toff the duration during which it is switched off.

18. Method according to any one of the preceding claims, the distance between the emission surface (10) of the acoustic waves of the transducer (13) and 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.

19. A method according to any preceding claim, the scanning speed of the surface by the transducer (13), in step (a), being between 5 and 15 cm2 / s.

20. Method according to any one of the preceding claims, the second cosmetic composition comprising at least one cosmetic active agent chosen from moisturizing agents, desquamating agents, humectants, anti-aging agents, mattifying agents, healing agents, anti-bacterial agents, vitamins and their derivatives or precursors, antioxidant compounds, sunscreens, anti-free radical agents, anti-polluting agents, self-tanning agents, anti-glycation agents, soothing agents, deodorant agents, essential oils, NO-synthase inhibitors, agents stimulating the synthesis of dermal or epidermal macromolecules and / or preventing their degradation, agents stimulating the proliferation of fibroblasts, agents stimulating the proliferation of keratinocytes, muscle relaxants, refreshing agents, tensing agents, depigmenting agents, pro-pigmenting agents,keratolytic agents, slimming agents, agents acting on the energy metabolism of cells, insect repellents, substance P or CRGP antagonists, anti-hair loss agents, and mixtures thereof.

21. A method according to any one of the preceding claims, the application of the second composition in step b) taking place as soon as the treatment of step a) is completed, or alternatively a little later, preferably less than 5 min after the end of step a).

22. A method according to any one of the preceding claims, comprising a step of rinsing said surface of keratin materials (K), between step (a) and step (b).

23. A method according to any preceding claim, comprising a step of pretreatment of said surface of the keratin materials (K), upstream of step (a).

24. Treatment assembly for implementing the method according to any one of the preceding claims, comprising, in particular within the same packaging: - the first cosmetic composition comprising a surfactant and / or an active agent chosen 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 the treatment of said surface.

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