Cosmetic treatment process for keratin fibers

Abstract

Cosmetic Treatment Process for Keratin Fibers. The invention relates to a cosmetic treatment process for keratin fibers (12), comprising the following steps: a) application to the keratin fibers of a cosmetic composition (14) comprising at least 5% by mass of water; then b) exposure of said keratin fibers to microwave radiation. The cosmetic composition (14) comprises at least one compound of general formula (I) in salified or non-salted form, with (I): R=C(NR1R2)(NR3R4), where R denotes α =O or α =NH₄⁺; and each of the substituents R1, R2, R3, R4 being selected from hydrogen and an alkyl substituent; and a total thiol concentration of the cosmetic composition is less than 10% by mass, preferably less than 5% by mass, more preferably less than 1% by mass, and even more preferably less than 0.1% by mass relative to the total mass of said cosmetic composition. Figure for the abbreviation: Figure 1

Description

Title of the invention: Method for the cosmetic treatment of keratin fibers

[0001] The present invention relates to a method for the cosmetic treatment of keratin fibers, preferably hair, said method comprising the following steps: a) application to the keratin fibers of a cosmetic composition comprising at least 5% by mass of water; then b) exposure of said keratin fibers to microwave radiation.

[0002] Such a method, for example described in document WO2011 / 141882 in the name of the Applicant, aims in particular to shape keratin fibers. Such a method aims, for example, to shape hair in a curly, wavy or straightened form.

[0003] Known methods of this type do not always allow rapid and effective shaping of the hair, nor lasting retention of the shape obtained.

[0004] Document WO2011 / 141882 also cites hair shaping techniques based on breaking disulfide bonds -SS- present in keratin. These techniques, particularly based on compositions comprising thiols, can cause degradation of keratin fibers.

[0005] The aim of the present invention is to propose a method of the aforementioned type, leading to rapid, efficient and lasting shaping of keratin fibers, while preserving the integrity of said fibers.

[0006] To this end, the invention relates to a cosmetic treatment process of the aforementioned type, in which the cosmetic composition comprises at least one compound of general formula (I) in salified or non-salified form, with

[0007] (I): R=C(NRiR2)(NR3R4),

[0008] =R denoting =0 or =NH; and

[0009] each of the substituents Rb R2, R3, R4 being chosen from hydrogen and an alkyl substituent; and

[0010] a total concentration of thiols in the cosmetic composition is less than 10% by mass, preferably less than 5% by mass, more preferably less than 1% by mass, even more preferably less than 0.1% by mass relative to a total mass of said cosmetic composition.

[0011] According to other advantageous aspects of the invention, the cosmetic treatment method comprises one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0012] - the compound of general formula (I) is urea;

[0013] - the compound of general formula (I) is in the form of a salt, said salt being preferred optionally selected from chlorides, hydrochlorides, acetates, carbonates, hydrogen carbonates, phosphates and citrates;

[0014] - a total concentration of compounds of general formula (I), in salified form or not, in the cosmetic composition is between 1% and 40% by mass, preferably between 3% and 30% by mass, more preferably between 5% and 25% by mass, relative to a total mass of said cosmetic composition;

[0015] - the pH of the cosmetic composition is between 3 and 12, preferably between 5 and 10;

[0016] - step b) of exposure to microwave radiation is carried out at a radiation power between 10 W and 300 W, preferably between 20 W and 100 W;

[0017] - step b) of exposure to microwave radiation is carried out at a radiation frequency between 500 MHz and 300 GHz, preferably between 500 MHz and 10 GHz, more preferably between 900 MHz and 5 GHz, even more preferably between 2 GHz and 3 GHz;

[0018] - a duration of step b) of exposure to microwave radiation is between 5 mins and 30 mins, preferably between 10 mins and 20 mins;

[0019] - the cosmetic treatment process further comprises a step c) of placing under tensioning of the keratin fibers, step b) of exposure to microwave radiation being carried out on the keratin fibers under tension;

[0020] - step c) of tensioning the keratin fibers is carried out by rolling said keratin fibers on a support;

[0021] - the keratin fibers under tension are arranged in a closed enclosure during step b) of exposure to microwave radiation.

[0022] The invention will be better understood on reading the description which follows, given solely by way of non-limiting example and made with reference to the drawings in which:

[0023] [Fig-1] [Fig. 1] is a schematic view of an assembly for implementing a method according to one embodiment of the invention.

[0024] [Fig.l] shows an assembly 10 for implementing a method according to one embodiment of the invention. The method relates to the cosmetic treatment of keratin fibers such as a lock 12 of hair.

[0025] The assembly 10 comprises in particular: a cosmetic composition 14; a device 16 for exposure to microwave radiation; and possibly a support 18 for the keratin fibers.

[0026] The cosmetic composition 14 is an aqueous composition. By aqueous is meant that it comprises at least 5% by mass of water relative to a total mass of the composition. The total mass of the composition is for example determined by considering a weight of said composition at a temperature of 25°C and at a pressure of 1 atm.

[0027] More preferably, the cosmetic composition 14 comprises at least 25% by mass of water, even more preferably at least 50% by mass of water, relative to a total mass of the composition.

[0028] Cosmetic composition 14 comprises at least one compound of general formula (I) in salified or non-salified form, with

[0029] (I): R=C(NR1R2)(NR3R4),

[0030] =R representing =0 or =NH; and

[0031] each of the substituents RB R2, R3, R4 being chosen from hydrogen and an alkyl substituent.

[0032] Preferably, at least one of the substituents RB R2, R3, R4 is hydrogen. More preferably, formula (I) denotes R=C(NH2)2, =R representing =0 or =NH.

[0033] Furthermore, a total concentration of thiols in the cosmetic composition is less than 10% by mass, preferably less than 5% by mass, more preferably less than 1% by mass, even more preferably less than 0.1% by mass, relative to a total mass of said cosmetic composition. A thiol is defined as an organic compound comprising a -SH group.

[0034] More generally, the cosmetic composition 14 does not contain a significant quantity of disulfide bond reducing agent.

[0035] The at least one compound of general formula (I) is chosen from: urea, with =R denoting =0; guanidine, with =R denoting =NH; and their salts. By "salt", it is meant that the compound is in ionic form and associated with a counter-ion, mineral or organic.

[0036] The salts are for example chosen from salts of mineral or organic acids, in particular: halides and in particular chlorides or hydrochlorides; acetates; carbonates; hydrogen carbonates; phosphates; citrates.

[0037] Preferably, the at least one compound of general formula (I) is chosen from urea and its salts.

[0038] Preferably, a total concentration of compounds of general formula (I), in salified form or not, in the cosmetic composition 14 is between 1% and 40% by mass relative to a total mass of said cosmetic composition. More preferably, said total concentration is between 3% and 30% by mass, even more preferably between 5% and 25% by mass, relative to the total mass of said cosmetic composition.

[0039] Preferably, the pH of the cosmetic composition 14 is between 3 and 12, more preferably between 5 and 10.

[0040] Preferably, the cosmetic composition 14 further comprises one or more compounds chosen from: solvents; silicone or non-silicone fatty substances; anionic, cationic, non-ionic or amphoteric surfactants, silicone or non-silicone; polymers, preferably anionic, cationic, non-ionic or amphoteric treating or thickening polymers; anti-dandruff agents; anti-hair loss agents.

[0041] Preferably, the cosmetic composition 14 is in liquid or viscous form, for example in the form of a serum, gel or cream.

[0042] The device 16 for exposure to microwave radiation comprises a microwave generator 20. In the embodiment of the invention visible in [Fig.l], the device 16 further comprises an antenna 22 and an enclosure 24.

[0043] In the embodiment shown, the generator 20 is capable of implementing an exposure of the keratin fibers to microwave radiation at a radiation power of between 10 W and 300 W, preferably between 20 W and 100 W.

[0044] In the embodiment shown, the generator 20 is capable of implementing an exposure of the keratin fibers to microwave radiation at a radiation frequency of between 500 MHz and 300 GHz, preferably between 500 MHz and 10 GHz, more preferably between 900 MHz and 5 GHz, even more preferably between 2 GHz and 3 GHz.

[0045] Preferably, the generator 20 comprises an electronic module storing a program in which the power and frequency of the microwaves are set, as well as possibly an exposure duration. Preferably, the generator 20 further comprises an interface allowing a user to select parameters for exposing the keratin fibers to the microwaves.

[0046] In the embodiment shown, the antenna 22 comprises a rod 26 and a base 28. The rod 26 forms a free end of the antenna 22. The base 28 extends the rod 26 and is connected to the generator 20 by an electrical connection cable 30.

[0047] The enclosure 24 is intended to contain the keratin fibers, in particular the lock 12 of hair, during exposure to microwave radiation. For this purpose, the enclosure 24 is configured to receive the antenna 22, as detailed below.

[0048] For example, the assembly 10 comprises a housing 32 comprising two similar elements 34, hinged to one another. Each element 34 comprises a cavity 36 delimited by an edge 38. The enclosure 24 is materialized by the housing 32 arranged in a closed configuration, the edges 38 of the two cavities 36 being in contact with one another, said cavities 36 forming the enclosure 24.

[0049] One end of each cavity is extended by a groove 40. In the closed configuration, the grooves 40 form an orifice for the passage of the cable 30.

[0050] Preferably, each cavity 36 comprises walls 42 coated with a material insulation, allowing the microwaves to be contained inside the enclosure 24.

[0051] In the embodiment shown, the edge 38 of at least one of the cavities 36 comprises a series of notches 44 capable of receiving keratin fibers, as detailed below.

[0052] Other enclosures that can be used in the context of the present invention are described in the document WO2011 / 141882 cited above.

[0053] The support 18 is intended to tension the keratin fibers during their exposure to microwave radiation. In the embodiment shown, the support 18 has a tubular shape. More precisely, the support 18 is of the roller or curler type.

[0054] In particular, the support 18 is intended to be received in the enclosure 24 during the exposure of the keratin fibers to microwave radiation. More precisely, the support 18 comprises: an external surface 46 of revolution, capable of allowing the lock 12 of hair to be wound; and an internal space 48, open at at least one end, capable of allowing the rod 26 of the antenna 22 to be inserted into said internal space.

[0055] In the embodiment shown, the device 16 and the support 18 are configured for shaping the lock 12 of hair in a curly or wavy form. In a variant not shown, the support is intended to tension the keratin fibers in an elongated or flattened configuration, to allow them to be smoothed. Similarly, the device for exposure to microwave radiation, in particular the enclosure, is configured to receive such a support.

[0056] A cosmetic treatment method according to one embodiment of the invention, implemented using the assembly 10 described above, will now be described.

[0057] We consider a lock 12 of hair forming part of a user's hair.

[0058] In a first step of the method, the lock 12 of hair is impregnated with a dose of cosmetic composition 14.

[0059] In a second step, the strand 12 is wound around the support 18, so as to be put under tension. In particular, a first part 50 of the strand 12, comprising the tips of the hair, is in contact with the external surface 46 of the support; and a second part 52 of said strand 12, located on the side of the user's skull, is kept under tension at a distance from said external surface 46.

[0060] The second winding step can be carried out before, after or simultaneously with the first impregnation step.

[0061] In a third step, the wick 12 and the support 18 are assembled to the device 16. More precisely, the rod 26 of the antenna 22 is inserted into the support 18. Then, said antenna 22 is arranged in the cavity 36 of a first element 34 of the housing, the cable 30 being arranged in the groove 40. The wick 12 is arranged so that the second part 52 of said wick 12 is arranged in the notches 44 of the edge 38 of the cavity 36. Then, the second element 34 of the housing is folded down, so as to place said housing in the closed configuration and to form the enclosure 24. The second part 52 of the wick 12 emerges outside of said enclosure, through openings formed by the notches 44.

[0062] In a fourth step, the generator 20 emits microwaves, at a configured power and frequency. Via the antenna 22, the first part 50 of the wick 12, arranged inside the enclosure 24, is thus exposed to microwave radiation.

[0063] The microwaves, in reaction with the water contained in the cosmetic composition 14, allow in particular the generation of heat at the heart of the keratin fibers and generate chemical reactions between said fibers and compounds present in the cosmetic composition 14.

[0064] The duration of the fourth step of exposure to microwaves is for example of the order of a few minutes. Preferably, the duration of the fourth step of exposure to microwaves is between 5 minutes and 30 minutes, more preferably between 10 and 20 minutes.

[0065] According to one embodiment, the cosmetic treatment method then comprises a step of rinsing the lock 12 of hair, preferably with water.

[0066] The cosmetic treatment process described above allows rapid and effective shaping of the hair, in particular in curly, wavy or straightened form. The shaping has a satisfactory duration, in particular of the order of several months.

[0067] In addition, the treated hair is not or only slightly degraded by the cosmetic treatment, which makes it possible to repeat said treatment frequently.

[0068] Such a cosmetic treatment is therefore suitable for frequent hair reshaping, in order to vary the physical appearance of users on demand.

Claims

Claims

1. Process for the cosmetic treatment of keratin fibers (12), preferably hair, said process comprising the following steps: a) application to the keratin fibers of a cosmetic composition (14) comprising at least 5% by mass of water; then b) exposure of said keratin fibers to microwave radiation; the process being characterized in that: the cosmetic composition (14) comprises at least one compound of general formula (I) in salified or non-salified form, with (I): R=C(NRiR2)(NR3R4), =R denoting =0 or =NH; and each of the substituents RB R2, R3, R4 being chosen from hydrogen and an alkyl substituent; and a total concentration of thiols in the cosmetic composition is less than 10% by mass, preferably less than 5% by mass, more preferably less than 1% by mass, even more preferably less than 0.1% by mass relative to a total mass of said cosmetic composition.

2. Cosmetic treatment method according to claim 1, wherein the compound of general formula (I) is urea.

3. Cosmetic treatment method according to claim 1 or 2, in which the compound of general formula (I) is in the form of a salt, said salt being preferentially chosen from chlorides, hydrochlorides, acetates, carbonates, hydrogen carbonates, phosphates and citrates.

4. Cosmetic treatment method according to one of the preceding claims, in which a total concentration of compounds of general formula (I), in salified form or not, in the cosmetic composition (14) is between 1% and 40% by mass, preferably between 3% and 30% by mass, more preferably between 5% and 25% by mass, relative to a total mass of said cosmetic composition.

5. Cosmetic treatment method according to one of the preceding claims, in which the pH of the cosmetic composition (14) is between 3 and 12, preferably between 5 and 10.

6. Cosmetic treatment method according to one of the preceding claims, in which step b) of exposure to microwave radiation is carried out at a radiation power of between 10 W and 300 W, preferably between 20 W and 100 W.

7. Cosmetic treatment method according to one of the preceding claims, in which step b) of exposure to microwave radiation is carried out at a radiation frequency of between 500 MHz and 300 GHz, preferably between 500 MHz and 10 GHz, more preferably between 900 MHz and 5 GHz, even more preferably between 2 GHz and 3 GHz.

8. Cosmetic treatment method according to one of the preceding claims, in which a duration of step b) of exposure to microwave radiation is between 5 min and 30 min, preferably between 10 min and 20 min.

9. Cosmetic treatment method according to one of the preceding claims, further comprising a step c) of tensioning the keratin fibers (12), step b) of exposure to microwave radiation being carried out on the tensioned keratin fibers.

10. Cosmetic treatment method according to claim 9, in which step c) of tensioning the keratin fibers is carried out by winding said keratin fibers (12) on a support (18).

11. Cosmetic treatment method according to claim 9 or 10, in which the keratin fibers under tension are arranged in a closed enclosure (24) during step b) of exposure to microwave radiation.