Hair treatment method
The present invention relates to a cosmetic hair treatment method comprising at least the steps consisting of: a) applying a mechanical tension to said hair, b) exposing said hair under mechanical tension to microwaves, in the presence of a solvent in vapor form in contact with said hair, without complete drying of the hair during microwave exposure, the solvent in vapor form being entirely generated by the evaporation of a compound which is present, before emission of the microwaves, in contact with the treated hair.
1. A cosmetic hair treatment method comprising:
a) applying a mechanical tension to the hair to be treated,
b) exposing the hair under the mechanical tension to microwaves, while contacting the hair with a solvent vapour, without complete drying of the hair during the microwave exposure, to obtain the treated hair;
wherein
the solvent vapour is generated by evaporation of a solvent which is in contact with the hair to be treated before the exposure to the microwaves, the solvent vapour having, in the vicinity of and/or in contact with the hair, in step b), a temperature of between 100 and 150° C.; and
after step b) the hair retains at least 5% of the weight of liquid compounds present before step b), in contact therewith, the liquid compound adding to natural moisture of the hair before treatment,
and wherein a frequency of the microwaves is between 500 MHz and 10 GHz,
the method further comprising c) applying to the treated hair at least one composition for durable shaping of the hair, the composition being a reducing composition comprising one or more reducing agents, the pH of the reducing composition being between 7 and 11, the reducing composition comprising at least one alkalifying agent, the alkalifying agent being selected from:
aqueous ammonia,
alkanolamines and derivatives thereof,
ethoxylated and/or propoxylated ethylenediamines,
alkali metal silicates,
amino acids,
compounds of formula (II):
wherein
W is a propylene residue which is optionally substituted by a hydroxyl group, or a C1-C4 alkyl radical, and
Ra, Rb, Rc and Rd are identical or different and may be a hydrogen atom or a C1-C4 alkyl or C1-C4 hydroxyalkyl radical.
2. The method according to claim 1 , wherein a) and b) are successive or simultaneous.
3. The method according to claim 1 , wherein the at least one composition for durable shaping of the hair comprises at least one selected from the group consisting of a reducing agent, an alkali metal hydroxide and an alkaline earth metal hydroxide.
4. The method according to claim 1 , wherein the shaping composition is applied to the hair before a), after b) or both before a) and after b).
5. The method according to claim 1 , further comprising applying to the treated hair at least one fixing composition comprising one or more oxidizing agents.
6. The method according to claim 5 , wherein the fixing composition is applied to the hair before a), after b) and after c) or after b) and after c).
7. The method according to claim 1 wherein the mechanical tension in a) comprises application to the hair to be treated of at least one selected from the group consisting of a torsional stress, a tensile stress and a compressive stress.
8. The method according to claim 1 , wherein a duration of b) is between 1 s and 30 min.
9. The method according to claim 1 , wherein the microwaves having a power of the microwaves is less than 500 W.
10. The method according to claim 1 , wherein the solvent comprises a polar protic liquid having a dielectric constant at 20° C. greater than or equal to 8.
11. The method according to claim 1 , wherein the solvent vapour comprises at least one of water and propanol.
12. The method according to claim 1 wherein b) takes place in an enclosure which is impervious to microwaves.
13. The method according to claim 1 , further comprising recovering the solvent vapour during b), after b) or both during and after b).
14. The method according to claim 1 , wherein during part or a total of b), the hair is in a volume defined by at least a wall of a material which allows passage of microwaves and limits evaporation of the solvent in contact with the treated hair before emission of the microwaves.
15. The method according to claim 14 , wherein the material comprises cellophane.
16. The method according to claim 1 , wherein the solvent vapour is entirely generated by said evaporation of said solvent which is in contact with the hair to be treated before the exposure to the microwaves.
17. The method according to claim 1 , wherein the solvent vapour comprises propanol.
18. The method according to claim 1 , wherein step b) is repeated between 2 and 10 times.
19. The method according to claim 1 , wherein the alkalifying agent is an alkanolamine selected from the group consisting of monoethanolamine, diethanolamine and triethanolamine and derivatives thereof.
20. The method according to claim 1 , wherein the alkalifying agent is an alkali metal silicate, which is a sodium metasilicate.
21. The method according to claim 1 , wherein the alkalifying agent is an amino acid selected from the group consisting of arginine, lysine, ornithine, citrulline and histidine.