Hair dyeing method

Abstract

The present invention relates to a cosmetic hair dyeing process comprising at least the following steps: (a) applying an aqueous dyeing composition comprising one or more ionic direct dyes to at least one strand of hair, (b) exposing the hair impregnated with the dyeing composition to microwave radiation.

Description

Technical Field

[0001] The present invention relates to a method for dyeing hair. Background Art

[0002] Many techniques have been proposed for dyeing hair, using different types of dyeing compositions.

[0003] Furthermore, the use of microwave radiation to increase the effect of detergents is known in the field of surface care. In particular, patent applications WO 98 / 03621, WO 98 / 03622, WO 98 / 03623, WO 99 / 25802 and WO 99 / 37745 describe the treatment of hard surfaces by combining exposure to microwave radiation with detergents containing bleach.

[0004] In the field of hair shaping, patent applications DE 3148538, US 2006 / 0108358, US 2010 / 0006116 or US 2007 / 056860 disclose the use of microwave radiation directly on the hair.

[0005] Document US 2006 / 042649 and US 6079422 describe heatable curling irons that can be placed in a microwave oven before being used to curl hair. In these documents, the heating aspect of microwaves is used, but these microwaves are not in direct contact with the hair.

[0006] Patent application WO 2013 / 183021 discloses a method for treating keratin fibers comprising applying a shaping composition, followed by mechanical tension, and then exposure to microwave radiation.

[0007] Patent applications WO 2011 / 141882 and FR 3062786 describe hair treatment methods having a step of placing under mechanical tension and a step of exposure to microwave radiation.

[0008] Patent application WO 2013 / 125052 describes a method for coloring hair using synthetic direct dyes and heating keratin fibers.

[0009] Patent application WO 2019 / 122850 discloses a method for dyeing hair using a dye composition and simultaneously treating with radio wave radiation having a frequency between 1 MHz and 300 MHz.

[0010] Shaping the hair and coloring the same hair usually require two different operations, which on the one hand cumulatively result in having to remain still for a long time and on the other hand, immediate successive applications are not recommended due to the risk of denaturation of the color obtained on the hair and, moreover, a significantly increased risk of damaging the keratin fibers.

[0011] Consequently, there remains a need to improve hair colouring methods by increasing their effectiveness while preserving as much of the hair fibre as possible, and in particular to provide more effective direct colouring, i.e. with enhanced colour intensity and / or reduced selectivity and / or improved permanence, in particular relative to shampoo washing.

[0012] There is also a need for a method for simultaneous coloring and shaping of hair. Summary of the Invention

[0013] Dyeing method The present invention aims to meet this need and the subject of the invention is a cosmetic hair coloring process comprising at least the steps consisting of: (a) applying an aqueous dyeing composition comprising one or more ionic direct dyes to at least one lock of hair, (b) exposing the hair impregnated with the dyeing composition to microwave radiation.

[0014] The method according to the invention makes it possible to obtain an improved hair coloring process due to the specific combination of ionic direct dyes and microwave radiation. The use of microwave radiation while the coloring composition is still present on the hair provides targeted excitation of the molecules, making it possible to reduce the exposure time for equivalent results.

[0015] It is also possible to reduce the concentration of ionic direct dyes used to achieve a given level of coloration.

[0016] The dyeing results are very good, in particular with good dye accumulation, good permanence and low selectivity, while limiting the damage caused to the hair.

[0017] Compositions having a pH lower than that of known dyeing compositions may also be used.

[0018] The use of microwave radiation makes it possible to accelerate the dyeing reaction and thus reduce the residence time required for the composition.

[0019] The durability and uniformity of the results obtained from the method according to the invention are very good and reduce the damage experienced by the hair and limit the risk of irritation.

[0020] Depending on the duration of exposure to microwave radiation, and in particular on the base colour of the lock of hair, different results are obtained.

[0021] The duration of exposure to microwave radiation may range from 1 second to 30 minutes, better from 1 second to 10 minutes, even better from 1 second to 5 minutes, very preferably from 1 second to 3 minutes.

[0022] The method according to the invention may additionally comprise a hair shaping step (d), in particular a step of winding the lock of hair onto a curler, said step (d) in particular comprising applying mechanical tension to said lock of hair via a device in particular for applying mechanical tension, said device having a receiving surface intended to receive the lock of hair.

[0023] The method according to the invention can thus simultaneously contribute to a certain shaping of the hair and also offers the possibility of performing a coloring and shaping treatment simultaneously in a durable, rapid and satisfactory manner. The curls are well-defined and sufficiently durable with limited damage.

[0024] In this variant, the shaping step (d) may be carried out before step (a) of applying the composition or between step (a) and step (b) of exposing to microwave radiation.

[0025] The method according to the present invention may additionally comprise one or more pre-treatment steps occurring before steps (a) and (b) and / or before or after step (d) (if applicable).

[0026] The process according to the present invention may additionally comprise one or more post-treatment steps taking place after step (b) and / or after step (c) (if applicable).

[0027] These additional pre- or post-treatment steps may comprise applying one or more additional compositions in addition to the composition present during step (a).The microwave treatment may or may not be performed immediately after the application of these additional compositions.

[0028] In the case where the shaping step (d) is carried out, the method according to the invention may comprise a step (e) of applying a hair shaping composition comprising one or more fixing polymers or one or more agents that disrupt the disulfide bonds of keratin, such as thiol-containing reducing agents. Preferably, the method according to the invention does not comprise such a step (e).

[0029] The method according to the invention may additionally comprise one or more steps (c) of rinsing the hair after one or other of steps (a), (b) and (d), preferably a single rinsing step performed after step (b) of exposure to microwave radiation.

[0030] Composition The dyeing composition preferably comprises at least 5% by weight of water at ambient temperature (25° C.) and atmospheric pressure (760 mm Hg).

[0031] The dyeing composition can be produced from a mixture of several compositions, in particular a mixture of a composition comprising one or more ionic direct dyes (a1*) and an aqueous composition (a1**) comprising, in particular, at least one oxidizing agent. The aqueous composition (a1**) itself can be produced by mixing two or more compositions. The compositions are preferably mixed when the dyeing composition is used.

[0032] The dyeing composition (a1) may comprise at least one oxidizing agent.

[0033] Composition (a1) may include hydrogen peroxide. The hydrogen peroxide may be derived from an anhydrous hydrogen peroxide precursor such as urea peroxide, which is then present in the composition hydrolyzed in composition (a1**), or directly in composition (a1). More preferably, the hydrogen peroxide may be in the form of an aqueous hydrogen peroxide solution present in composition (a1**).

[0034] In one variant, composition (a1) does not contain any oxidizing agent. In this variant, the method according to the invention can comprise, after step (b), a step (f) of applying an oxidizing composition, said oxidizing composition thus preferably comprising hydrogen peroxide in an aqueous medium. Preferably, the method according to the invention does not comprise this step (f).

[0035] Preferably, the dyeing composition (a1) has a pH ranging from 1 to 13, better still from 1.5 to 12, even better still from 2.5 to 11.

[0036] The dyeing composition (a1) may include one or more pH agents, which may be alkaline agents or acidic agents.

[0037] Preferably, when composition (a1 ) comprises one or more direct acid dyes, it also comprises one or more acidic pH agents.

[0038] Preferably, when composition (a1 ) comprises one or more direct basic dyes, it also comprises one or more alkaline pH agents.

[0039] An agent is considered alkaline when, upon introduction into water at ambient temperature and atmospheric pressure at a concentration of 1% by weight, it results in a pH greater than 7. An agent is considered acidic when, upon introduction into water at ambient temperature and atmospheric pressure at a concentration of 1% by weight, it results in a pH less than 7.

[0040] The alkaline agent is preferably selected from alkali metal or alkaline earth metal hydroxides, alkali metal or alkaline earth metal carbonates, ammonia and alkanolamines. Among the alkanolamines, monoethanolamine is preferred.

[0041] The acidic agent is preferably selected from inorganic acids such as hydrochloric acid or phosphoric acid, organic acids and in particular hydroxy acids such as citric acid or lactic acid.

[0042] The concentration of the pH agent in the dyeing composition (a1 ) varies preferably from 0.01 % to 20%, better still from 0.01 % to 10%, even better still from 0.1 % to 5% by weight relative to the total weight of the composition.

[0043] The dyeing composition (a1 ) comprises one or more ionic direct dyes. By ionic direct dye is meant a dye bearing one or more permanent positive or negative charges. The ionic direct dyes can be anionic or cationic. They are in particular direct "acid" dyes and direct "basic" dyes.

[0044] The direct "acid" dyes bear at least one sulfonic or carboxylic group, in salt or non-salt form, in their structure. The direct "basic" dyes bear at least one quaternized nitrogen atom in the presence of at least one counterion in their structure.

[0045] As direct acid dyes, mention can be made of the dyes described in the Colour Index under the names Acid Yellow 1, Acid Orange 3, Acid Black 1, Acid Black 52, Acid Orange 7, Acid Red 33, Acid Yellow 23, Acid Blue 9, Acid Violet 43, Acid Blue 62, Acid Blue 25, Acid Red 4.

[0046] As direct basic dyes, mention can be made of the dyes described in the Colour Index under the names Basic Brown 17, Basic Red 118, Basic Orange 69, Basic Red 76, Basic Brown 16, Basic Yellow 57, Basic Violet 14, Basic Blue 7, Basic Blue 26, Basic Red 2, Basic Blue 99, Basic Yellow 29, Basic Red 51, Basic Orange 31, Basic Yellow 87, Basic Blue 124.

[0047] In the dyeing composition (a1 ), the concentration of ionic direct dyes can vary from 0.001 % to 20% by weight, better still from 0.01 % to 15% by weight, even better still from 0.1 % to 10% by weight, relative to the total weight of the composition.

[0048] The cosmetic composition used in the process according to the application can also comprise at least one compound chosen from solvents, silicone or non-silicone fatty substances, silicone or non-silicone anionic, cationic, nonionic or amphoteric surfactants, polymers, and in particular anionic, cationic, nonionic or amphoteric treatment or thickening polymers, antidandruff agents or agents for combating hair loss.

[0049] microwave radiation The term "microwaves" should be understood as meaning electromagnetic radiation having a frequency ranging from 500 MHz to 300 GHz.

[0050] Preferably, the frequency of the microwave radiation used in the process of the invention is in the range from 500 MHz to 300 GHz, better from 500 MHz to 10 GHz, even better from 900 MHz to 5 GHz, very preferably from 2 GHz to 3 GHz.

[0051] The power of the microwaves used during step (b) may be less than or equal to 500 W, preferably ranging from 10 W to 300 W, better still from 100 W to 250 W, even better still from 10 W to 50 W.

[0052] Preferably, the surface power density on the hair caused by microwave radiation can be from 0.1 W / cm 2 Up to 100 W / cm 2 within the range.

[0053] The exposure to microwave radiation can be performed by means of a microwave-emitting antenna, said antenna and at least a portion of the lock of hair to be treated being preferably inserted into an enclosure sealed against microwaves.

[0054] If applicable, at least during step (b), the capsule contains the hair to be treated, which is impregnated with the dyeing composition. The term "containing the hair" should be understood to mean containing the hair over all or part of its length and over a given width. The capsule can cover the hair, for example, over a length of 5 cm or more. Thus, a length of hair of at least 5 cm can be treated in the capsule at one time.

[0055] The enclosure may be at least partially defined by a housing having a shell configured to receive at least a portion of the hair to be treated and, if applicable, a hair shaping tool, and a cover that pivots relative to the shell between an open position permitting access to the shell and a closed position, the microwave transmitting antenna being positioned within the shell.

[0056] In one variant, the enclosure is in the form of a hood.

[0057] The capsule may not move relative to the hair being treated during emission of the microwaves or may move relative to the hair, thereby making it possible to treat hair of greater length.

[0058] The enclosure may comprise at least one seal of electrically conductive material, for example elastically deformable, making it possible to shield the microwaves used during step (b) while allowing the hair to escape from the enclosure. The seal may comprise a foam filled with electrically conductive particles, a brush formed of electrically conductive bristles or a comb comprising metal teeth.

[0059] In the case where the enclosure is in the form of a hood, the enclosure may have an electromagnetic shield through which the treated hair can pass. Such a shield makes it possible to treat the user's hair while protecting the user's head from the emitted microwaves. The electromagnetic shield is formed, for example, by a metal grid or mesh.

[0060] Components According to another of its aspects, another subject of the invention is an assembly for dyeing hair comprising: at least one dyeing composition comprising one or more ionic direct dyes; and means suitable for exposing the hair to microwave radiation as previously defined.

[0061] The device may comprise a microwave-emitting antenna, said antenna and at least a portion of the hair lock to be treated being inserted in particular into an enclosure sealed against microwaves as described above.

[0062] The microwaves may be generated internally in the device adapted to expose the hair to microwave radiation, or externally by a microwave generator, for example a solid-state generator such as a magnetron.

[0063] In one variation, the generator is located inside the enclosure.

[0064] Microwaves can be transmitted by non-linear antennas (such as helical antennas).

[0065] The antenna can be formed from a sufficiently rigid wire (e.g., having a diameter in the range of 1 mm to 3 mm) so as not to require maintenance or a support rod for the turns. In an alternative form, the antenna comprises a flexible wire or conductive trace positioned on a support structure (particularly a helical support structure). The support structure can be made of any dielectric material, preferably PTFE or glass.

[0066] When the antenna is helical, it preferably has a fixed helical pitch, for example in the range of 4 mm to 5 mm. The radius of the helix is ​​preferably constant, for example in the range of 4 mm to 10 mm. The diameter of the antenna is, for example, from 8 mm to 10 mm.

[0067] The axial extension of the antenna may vary from 50 mm to 80 mm, preferably from 65 mm to 75 mm.

[0068] The antenna may be positioned in a tube, in particular closed at one end. The tube may be made of PTFE or another dielectric material.

[0069] The antenna may also be embedded in a dielectric material, preferably a flexible dielectric material, in particular silicone.

[0070] The device suitable for exposing the hair to microwave radiation can comprise a hair shaping tool, in particular a tool for applying a mechanical tension, in particular a curling iron. The term "curling iron" denotes a tool which makes it possible to wrap the hair around the longitudinal axis of the device according to a defined diameter, thereby creating a mechanical tension based on this diameter. The diameter of the curling iron can be based on the desired curling effect.

[0071] The curling iron can have teeth at the end of the arm laterally delimiting the surface for receiving the hair, said teeth of the curling iron being advantageously positioned around the antenna.

[0072] The shaping tool, if applicable, can be configured to straighten the treated hair during exposure to microwaves.

[0073] The removal of the mechanical tension on the lock of hair is preferably carried out after step (b) of exposure to microwave radiation.

[0074] The device can comprise a housing able to receive the shaping tool. The housing can be coated with an electrically conductive foam positioned to overflow into the hair outlet slot. This makes it possible to obtain a good seal of closure by virtue of the deformability of the foam at the slot.

[0075] The shaping tool and the antenna, if applicable, form an integral assembly which is introduced into the enclosure.

[0076] The shaping tool can be made of PTFE or other dielectric material, in particular a thermoplastic dielectric material.

[0077] The device for implementing the method according to the application can comprise a sound and / or light warning system, for example to warn the user of a microwave leak out of the enclosure and / or of an excessive temperature inside the enclosure.

[0078] The device advantageously comprises a safety system which prevents the emission of microwaves when the enclosure is not closed and / or in the event of abnormal operation, for example in the event of a microwave leak and / or an excessive temperature.

[0079] The device can be configured to control the duration of the emission of microwaves so as not to reach a treatment duration which is liable to damage the hair.

[0080] The method according to the application can comprise a step of detecting the closure of the enclosure before step (b). For example, a contactor is actuated when the enclosure is closed.

[0081] The start of the emission of microwaves can depend on the detection of the closure of the enclosure. The continued emission of microwaves after the start of the emission of microwaves can depend on the absence of detection of a microwave leak, in particular by means of a sensor sensitive to microwaves and placed outside the enclosure.

[0082] The method according to the present invention may additionally include a step of detecting the positioning of the hair to be processed before step (b). This detection step can be performed, for example, by an optical sensor and / or a mechanical sensor. If applicable, detection can be performed indirectly by detecting the positioning of the shaping tool.

[0083] The method according to the invention may comprise a step of measuring the temperature to which the treated hair is subjected, for example during step (b).This step of measuring the temperature may be performed by a thermometer without contact with the hair.

[0084] The device may comprise the microwave generator and the shaping tool in the same handpiece.The term "handpiece" denotes the part which is manipulated by a user with one hand during treatment of the hair.

[0085] The device may comprise a sensor that is sensitive to a property of the individual hair (e.g. colour, mechanical strength, surface condition or moisture) and the device may control at least one parameter of the treatment based on the property thus detected, e.g. the energy of the microwaves, the temperature of the solvent, the duration of the treatment and / or the applied mechanical stress (if applicable).

[0086] The above-stated features of the method apply to the assembly, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] A better understanding of the present invention will be gained by reading the following description and examining the accompanying drawings, which are presented by way of illustration only and do not limit the present invention in any way.

[0088] Figure 1 The diagram shows various steps of an example of a hair dyeing method according to the present invention, Figure 2 An example of an apparatus suitable for implementing the method according to the invention is shown diagrammatically and partially, Figure 3 shows a handpiece in an open position of an example of a device suitable for implementing the method according to the invention, Figure 4 Shown in closed position Figure 3 The handpiece, Figure 5 shows the shaping tool once it has been removed from a handpiece of a variant of the device suitable for implementing the method according to the invention, and Figure 6 is suitable for carrying out the method according to the invention when the capsule is closed and comprises Figure 5 Cross-sectional and side views of the device of the forming tool. DETAILED DESCRIPTION

[0089] The various steps of an example of a hair dyeing method according to the present invention are Figure 1 and will be described in detail below.

[0090] In this example, during step 11 , an aqueous dyeing composition (a1 ) comprising one or more ionic direct dyes is applied to at least one lock of hair.

[0091] In step 12, the hair in contact with the dyeing composition is exposed to microwave radiation having a frequency greater than or equal to 500 MHz, preferably in the range of from 900 MHz to 5 GHz. The duration of exposure to microwave radiation is preferably in the range of from 1 second to 3 minutes. The surface power density on the hair caused by the microwave radiation may be in the range of from 0.1 W / cm 2 Up to 100W / cm 2 within the range.

[0092] In the example described, the method according to the invention additionally comprises one or more hair rinsing steps 13 , preferably a single hair rinsing step 13 , performed after the step 12 of exposing to microwave radiation.

[0093] The method according to the invention may additionally comprise a hair shaping step 14, in particular a step of winding the lock of hair onto a curling iron, said step 14 in particular comprising applying mechanical tension to said at least one lock of hair via a device for applying mechanical tension, said device having a receiving surface intended to receive said lock of hair. This shaping step 14 is carried out before step 11 of applying the dyeing composition or between steps 11 and 12.

[0094] The method according to the invention may additionally comprise one or more pretreatment steps 15 carried out before steps 11 and 12 , comprising, for example, the application of one or more additional compositions in addition to the composition used during step 11 .

[0095] One or more post-treatment steps 16 may be performed after step 12 and / or after step 13 , comprising, for example, the application of one or more additional compositions in addition to the composition used during step 11 .

[0096] Preferably, and as in the example described, the dyeing composition (a1) may be a mixture of several compositions, in the example in question a mixture of a composition (a1*) comprising one or more ionic direct dyes and an aqueous composition (a1**) comprising hydrogen peroxide, the mixing of the compositions being carried out when the dyeing composition is used. The pH of the dyeing composition (a1), the ionic direct dyes included in the dyeing composition (a1), and the optional pH agent, as well as their concentrations, are as described above.

[0097] Figure 2A device 100 suitable for implementing the method according to the present invention is shown, comprising a handpiece 3 connected to a base unit 1 comprising a microwave generator via a flexible waveguide 2. As illustrated, the handpiece 3 is arranged to be manipulated by a user so as to be placed close to a person's head in order to treat at least one lock of hair H. The handpiece 3 can be made in various ways and defines a treatment enclosure 4 that is sealed against microwaves.

[0098] exist Figure 3 In the example shown in FIG, the handpiece 3 comprises a housing 10 defining a casing 6, to which a cover 11 is hinged by means of a pin 12. Figure 4 The flexible waveguide 2 is shown as closed. Figure 3 and subsequent figures are only very partially shown 。

[0099] The housing 10 carries an antenna 30 which, in the example shown, has a helical shape with a longitudinal axis X.

[0100] In the example discussed, the antenna 30 consists of a helical metal wire positioned in a tube 32 of dielectric material, such as silicone or PTFE.

[0101] The antenna 30 is supported at one axial end of the housing 10 by an end plate 14 of the housing 10 , the end plate having a semicircular profile.

[0102] The cover 11 has a similar end plate 15 on the opposite side in order to close the opening 5 of the housing 6 , via which the shaping tool can be introduced into the handpiece 3 .

[0103] The inner surface of the housing 6 is defined by a conductive coating 7 which makes it possible to reflect microwaves and to seal the enclosure 4 against them. This coating 7 can be formed on the cover and the outer shell by conductive foam, for example in the form of a disk for the end plate 15 and a ring for the end plate 14, for example in the form of a semi-cylindrical shape.

[0104] The housing 10 and the cover 11 define an exit slot 19 for the hair, which is located at the bottom of the recess 18, on the opposite side of the pin 12 of the hinge.

[0105] like Figure 6 As seen in FIG, coating 7 preferably protrudes into groove 19, so that although hair passes, still produce the good sealing property of closure. Therefore, at 17 places, the edge of coating can slightly exceed the edge of the body of cover and the edge of shell, to close groove 19.

[0106] The handpiece 3 comprises means (not shown) for locking the lid in the closed position and an opening detector.

[0107] A temperature detector may be present inside the enclosure 4, for example on its inner surface, in order to measure the temperature of the strand of hair being treated, and a control system, for example with a microprocessor, may make it possible to interrupt or modulate the emission of microwaves if the detected temperature is greater than a predetermined threshold.

[0108] In the particular embodiment, the housing 10 defines a casing 6 for receiving a forming tool which, in the example in question, consists of Figure 5 The curling iron 20 shown in FIG. Figure 3 Insertion of the antenna into the interior of the curler 20 is facilitated by the presence of the tube 32 shown in FIG, in which the wire of the antenna 30 is positioned.

[0109] The curler comprises several arms 21 defining a surface for receiving the hairs H having a width L measured along the longitudinal axis X of the curler 20 .

[0110] In this example, the axis X is parallel to the axis of rotation of the cover 11 and coincides with the longitudinal axis 7 of the antenna 30 .

[0111] In the example in question, the curling iron 20 comprises four arms 21 slightly curved towards the axis X and having their smallest distance from the axis X at approximately mid-length.

[0112] The arms 21 may have ribs 23 oriented perpendicularly to the axis X in order to help keep the locks of hair spread out on the arms 21 , preferably occupying the entire width L as evenly as possible.

[0113] The arms 21 are connected at their ends to the annular portion 25 .

[0114] The curler 20 has teeth 26 at the end of the arms 21 which laterally delimit a surface for receiving the hair.

[0115] The curler 20 may be made of any dielectric material, preferably PTFE.

[0116] The curling iron 20 preferably has a rotationally symmetrical shape relative to a median plane of symmetry perpendicular to the axis X.

[0117] The curling iron 20 comprises a short post 27 with an enlarged head, which is connected at its base to the corresponding annular portion 25 and is supported on the coating 7, as shown. Figure 6 , so as to keep the curling iron centered in the housing 6.

[0118] The studs 27 are located, for example, between the teeth 26 , as shown.

[0119] The width W of the outlet slot 19 for the hair may be slightly greater than L, the length of the housing 6 being substantially equal to the length of the curler 20, so that the curler is fixed both axially and radially in the housing 6 except for a slight play.

[0120] To use the handpiece 3, a lock of hair impregnated with the dyeing composition is rolled onto the curler 20 and then placed inside the housing 10 by moving it sideways relative to the housing and introducing it through the opening 5. Subsequently, the lid 11 is closed again and the hair comes out through the slot 19. Once the microwave exposure has taken place, the lock of hair is extracted by performing the operations in the reverse order.

[0121] Example Examples of results obtained by the method according to the invention are summarized in Table 4 below.

[0122] In this example, coloration tests were performed on SA50 type sensitized Caucasian hair.

[0123] The composition used according to the invention in this example is a dyeing composition (a1) comprising a basic blue 99 cationic direct dye (C1). This is compared with another dyeing composition not covered by the present invention, which comprises a nonionic direct dye HC blue 14 (C2). Both of these dyeing compositions produce a blue hue.

[0124] The composition is as follows: [Table 1] C1 ingredients %concentration Basic Blue 99 0.3 CHROMACARE Matrix 75 water QSP 100

[0125] [Table 2] C2 ingredients %concentration HC Blue 14 1.5 CHROMACARE Matrix 75 water QSP 100

[0126] [Table 3] 75% CHROMACARE base ingredients %concentration Cetyl Alcohol 1.333 Cetearyl Alcohol 5 Guar Hydroxypropyltrimonium Chloride 0.133 Hydroxyethyl cellulose 0.267 Behenyltrimethylammonium chloride 3.467 Chlorhexidine digluconate 0.267 Citric acid 0.033 C12-15 alkyl benzoate 0.667 Amodimethicone (and) Trideceth-6 (and) Cetrimonium Chloride 2.667 water QSP 100

[0127] The two dye compositions were applied to both sides of a strand of hair using a brush. The impregnated strands were then exposed to microwave radiation at a power setting of 100 W for 3 minutes.

[0128] The color parameters observed are L, a, b and ΔE. The ΔE parameter corresponds to the measurement of the change in the visual perception of two given colors before and after treatment by the method of the invention, similar to an increase in coloration.

[0129] The results obtained by implementing the method according to the invention were compared with the results obtained by implementing a dyeing method of the prior art without using microwave radiation, in which the hair impregnated with the dyeing composition was heated to 90° C. for 3 minutes.

[0130] [Table 4] Hair and how to use L a b ΔE Untreated hair (SA50) 67.55 +5.16 +26.46 - The present invention: SA50 cationic dye C1 MO 100W 3mn 30.12 -6.07 -9.17 52.86 Existing technology SA50 cationic dye C1 90℃ 3mn 32.68 -8.65 -8.39 51.20 SA50 Nonionic Dye C2 MO 100W 3mn 46.01 -14.70 -7.88 45.14 Existing technology: SA50 nonionic dye C2 90°C 3mn 34.41 -11.61 -21.99 61.04

[0131] Compared to the prior art process, the color rise is higher in the case of the direct cationic dye C1 when microwaves are used. However, in the case of the nonionic direct dye C2, the color rise is greatly reduced by using microwaves.

[0132] Many modifications may be made to the methods and apparatus just described without departing from the scope of the present invention.

[0133] The present invention is not limited to a particular type of forming tool or a particular type of microwave transmitting antenna.

Claims

1. A method for coloring hair, comprising at least the following steps: (a) applying an aqueous dyeing composition (a1) comprising one or more ionic direct dyes to at least one lock of hair, (b) exposing the hair impregnated with the dyeing composition to microwave radiation.

2. The method according to claim 1, wherein The frequency of the microwave radiation used in the method of the invention is in the range from 500 MHz to 300 GHz, better still from 500 MHz to 10 GHz, even better still from 900 MHz to 5 GHz, very preferably from 2 GHz to 3 GHz.

3. The method according to claim 1 , further comprising a hair shaping step (d), in particular a step of winding the hair lock on a curler, said hair shaping step (d) in particular comprising applying mechanical tension to said at least one hair lock via a device specifically for applying mechanical tension, said device having a receiving surface intended to receive said hair lock, said shaping step (d) preferably being carried out before step (a) of applying said composition or between step (a) and step (b) of exposing to microwave radiation.

4. A method according to any one of the preceding claims, wherein The dyeing composition (a1) results from a mixture of several compositions, in particular a mixture of a composition comprising one or more ionic direct dyes (a1*) and an aqueous composition (a1**) comprising in particular at least one oxidizing agent, said mixing of said compositions being carried out in particular at the time of use of the dyeing composition.

5. A method according to any one of the preceding claims, wherein The dyeing composition (a1) comprises at least one oxidizing agent.

6. The method according to the preceding claim, wherein: The dyeing composition (a1) comprises hydrogen peroxide, in particular in the form of an aqueous hydrogen peroxide solution present in the composition (a1**).

7. The method according to any one of claims 1 to 4, wherein The dyeing composition (a1) does not have any oxidizing agent.

8. A method according to any one of the preceding claims, wherein The dyeing composition (a1) has a pH ranging from 1 to 13, better still from 1.5 to 12, even better still from 2.5 to 11.

9. A method according to any one of the preceding claims, wherein The dyeing composition (a1) comprises one or more pH agents, in particular alkaline agents or acidic agents.

10. The method according to the preceding claim, wherein In the dyeing composition (a1), the concentration of the pH agent varies from 0.01% to 20% by weight, better still from 0.01% to 10% by weight, better still from 0.1% to 5% by weight relative to the total weight of the composition.

11. A method according to any one of the preceding claims, wherein In the dyeing composition (a1), the concentration of ionic direct dyes varies from 0.001% to 20% by weight, better still from 0.01% to 15% by weight, and even better still from 0.1% to 10% by weight relative to the total weight of the composition.

12. A method according to any one of the preceding claims, wherein Said exposure to microwave radiation is carried out by means of a microwave-emitting antenna, said antenna and at least a portion of said lock of hair to be treated being inserted into an enclosure sealed against microwaves.

13. The method according to any one of the preceding claims, wherein The surface power density on the hair caused by the microwave radiation is from 0.1 W / cm 2 Up to 100 W / cm 2 within the range.

14. A method according to any one of the preceding claims, wherein The duration of said exposure to said microwave radiation ranges from 1 second to 30 minutes, better still from 1 second to 10 minutes, even better still from 1 second to 5 minutes, very preferably from 1 second to 3 minutes.

15. An assembly for dyeing hair, comprising: at least one dyeing composition comprising one or more ionic direct dyes; And means suitable for exposing said hair to microwave radiation having a frequency ranging from 500 MHz to 300 GHz, better from 500 MHz to 10 GHz, even better from 900 Mhz to 5 Ghz, very preferably from 2 Ghz to 3 GHz.

16. Assembly according to the preceding claim, wherein The device comprises a microwave-emitting antenna (30), which and at least a portion of the hair strand to be treated are inserted into a microwave-tight enclosure (4).

17. An assembly according to claim 15 or 16, wherein The device comprises a hair shaping tool, in particular a tool for applying mechanical tension, in particular a curling iron.

Images