PROCESS FOR CURLING KERATIN FIBRES COMPRISING THE APPLICATION TO THE FIBRES OF A COMPOSITION CONTAINING THIOLACTIC ACID

Abstract

The present invention relates to a process for curling keratin fibres, such as the hair, which comprises at least the rolling of said fibres around one or more curling means, the application of a reductive acidic cosmetic composition, and a step of heating said fibres. The invention also relates to the use of said cosmetic composition for curling keratin fibres which have been dyed and/or lightened beforehand.

Claims

1. Process for curling keratin fibres, in particular human keratin fibres such as the hair, comprising at least the following steps: i) rolling said fibres around one or more keratin fibre curling means; ii) applying to said fibres an aqueous cosmetic composition: a. comprising at least one reducing agent chosen from thiolactic acid, salts thereof, and mixtures thereof, and b. with a pH between 2.5 and 6; iii) heating said fibres to a temperature of greater than or equal to 35° C.; it being understood that step iii) is performed after steps i) and ii).

2. Process according to the preceding claim, characterized in that there is no step of rinsing said keratin fibres between the implementation of step ii) and the implementation of step iii).

3. Process according to either of the preceding claims, characterized in that the curling means are chosen from curlers and heated curlers.

4. Process according to any one of the preceding claims, characterized in that the content of reducing agent(s) chosen from thiolactic acid, salts thereof, and mixtures thereof, is between 1% and 15% by weight, preferably between 2% and 13% by weight, more preferentially between 3% and 12%, and even more preferentially between 4% and 10% by weight, relative to the total weight of the composition.

5. Process according to any one of the preceding claims, characterized in that said composition also comprises one or more additional agents chosen from one or more nonionic surfactants, one or more cationic surfactants, one or more anionic surfactants, one or more thickening polymers, one or more silicones, one or more alkaline agents, and/or one or more non-silicone fatty substances.

6. Process according to the preceding claim, characterized in that: the total content of nonionic surfactant(s) is between 0.01% and 20% by weight, better still between 0.1% and 15% by weight, even better still between 0.2% and 10% by weight, or even between 0.5% and 6% by weight, relative to the total weight of the composition; and/or the total content of cationic surfactant(s) is between 0.1% and 10% by weight, better still between 0.5% and 8% by weight, even better still between 1% and 5% by weight, relative to the total weight of the composition; and/or the total content of anionic surfactant(s) is between 0.10% and 10% by weight, better still between 0.5% and 8% by weight, even better still between 1% and 5% by weight, relative to the total weight of the composition; and/or the total content of thickening polymer(s) is between 0.01% and 10% by weight, better still between 0.05% and 8% by weight, even better still between 0.1% and 5% by weight, or even between 0.4% and 2% by weight, relative to the total weight of the composition; and/or the total content of silicone(s) is between 0.01% and 15% by weight, better still between 0.05% and 10% by weight, even better still between 0.1% and 5% by weight, relative to the total weight of the composition; and/or the total content of alkaline agent(s) is between 0.1% and 10% by weight, better still between 0.3% and 10% by weight and even better still between 0.4% and 5% by weight, relative to the total weight of the composition; and/or the total content of fatty substance(s) is between 0.010% and 20% by weight, better still between 0.1% and 15% by weight, even better still between 0.5% and 10% by weight, relative to the total weight of the composition.

7. Process according to any one of the preceding claims, characterized in that the pH of said composition between 3 and 5, preferentially between 3 and 4.

8. Process according to any one of the preceding claims, characterized in that step i) is performed before step ii); preferably, said composition is liquid; more preferentially, the viscosity of said composition is less than 500 mPa.Math.s, better still less than 250 mPa.Math.s, even better still less than 100 mPa.Math.s.

9. Process according to any one of claims 1 to 7, characterized in that step ii) is performed before step i); preferably, said composition is in thickened form; more preferentially in the form of a cream or a gel; even more preferentially, the viscosity of said composition is greater than 500 mPa.Math.s, even better still between 550 and 2000 mPa.Math.s.

10. Process according to any one of the preceding claims, characterized in that said fibres are heated to a temperature of between 35 and 210° C.; preferably between 35 and 100° C. and more preferentially between 40 and 80° C.

11. Process according to any one of the preceding claims, characterized in that step iii) of heating said fibres lasts for between 10 and 45 minutes; preferably between 15 and 30 minutes.

12. Process according to any one of the preceding claims, characterized in that it comprises a step v) of applying to said fibres an oxidizing composition comprising one or more chemical oxidizing agents, performed after step iii); preferably, said oxidizing composition comprises hydrogen peroxide and/or persalts.

13. Process according to any one of the preceding claims, characterized in that it comprises a step vi) of rinsing said keratin fibres, performed after step iii), and before the optional step v).

14. Use of the cosmetic composition as defined in any one of claims 1 and 4 to 7 for curling keratin fibres, in particular human keratin fibres such as the hair, which have been dyed and/or lightened beforehand.

Description

EXAMPLES

Example 1

[0584] The cosmetic composition A that may be used in the process according to the invention is prepared from the ingredients shown in the table below, the amounts of which are expressed as weight percentages of active material (AM).

TABLE-US-00001 A INGREDIENTS (invention) Thiolactic acid 8 PEG-12 Dimethicone 2 Polysorbate 20 1 2-Amino-2-methylpropan-1-ol 2 Water qs 100 pH 3.5 ± 0.2

Tensile Test:

[0585] 2.7 g locks of hair 26 cm long, which have been highly sensitized by bleaching, washed beforehand with a standard shampoo (Pro-Classique from L'Oreal Professionnel), are wound while wet onto curlers.
The locks are then treated according to processes 1 and 2 below:

Process 1 (Invention):

[0586] In the following order: [0587] Application of composition A according to the invention, in a proportion of 5.4 g of composition per lock, [0588] Heating of the locks for 15 minutes at a temperature of 40° C. (Climazon infrared lamp), and the locks are covered with a stretchable plastic film, [0589] Rinsing of the locks with water, [0590] Application of an oxidizing composition comprising 2.4% by weight of H.sub.2O.sub.2, relative to the total weight of the oxidizing composition. The locks are then left to stand for 10 minutes at room temperature (25° C.), [0591] Rinsing of the locks with water, [0592] Natural drying.

Process 2 (Comparative):

[0593] In the following order: [0594] Application of a conventional permanent-waving reducing composition (notably comprising 6.7% by weight of ammonium thioglycolate and 0.01% by weight of cysteine, relative to the total weight of the composition, pH 8.5±0.2), in a proportion of 5.4 g of composition per lock, [0595] The locks are left to stand for 10 minutes at room temperature (25° C.), [0596] Rinsing of the locks with water, [0597] Application of an oxidizing composition comprising 2.4% by weight of H.sub.2O.sub.2, relative to the total weight of the oxidizing composition. The locks are then left to stand for 10 minutes at room temperature (25° C.), [0598] Rinsing of the locks with water, [0599] Natural drying.

[0600] On conclusion of the various processes and removal of the curlers, 33 hair strands are taken from each of the locks thus treated with composition A or the comparative composition. 33 hair strands are also taken from a lock of untreated hair which has been highly sensitized by bleaching.

[0601] Tensile tests are then performed on each of the fibres: the tensile strength is measured during the elongation of the fibre to the point of rupture, using a Dia-stron tensile testing machine. The breaking strength of the hair is then calculated. The higher the breaking strength, the more resistant the hair is to breaking, and thus the more its integrity is conserved.

The mean breaking strength values (MPa) are given below:

TABLE-US-00002 Protocol Breaking strength (MPa) Control 118.5 ± 9.9 Process 1 (invention) 110.3 ± 7.2 Process 2 (comparative)  80.3 ± 4.6

[0602] It is observed that process 1 according to the invention leads to higher breaking strengths, and thus to better conservation of the integrity of the hair, relative to the comparative process 2.

[0603] Other examples of cosmetic compositions that may be used in the process according to the invention were prepared from the ingredients shown in the table below, the amounts of which are expressed as weight percentages of active material (AM).

TABLE-US-00003 B INGREDIENTS (invention) Thiolactic acid 8 Dimethicone and amodimethicone 2 Steareth-20 1 Cetearyl alcohol 5 Behentrimonium chloride 3.2 Scleroglucan gum 0.46 Xanthan gum 0.15 2-Amino-2-methylpropan-1-ol 3 Water qs 100 pH 3.5 ± 0.2

TABLE-US-00004 C INGREDIENTS (invention) Thiolactic acid 8 PEG-12 Dimethicone 2 Polysorbate 20 1 Hydroxyethylcellulose 0.75 2-Amino-2-methylpropan-1-ol 2 Water qs 100 pH 3.5 ± 0.2

Example 2

[0604] The cosmetic compositions A and B are prepared from the ingredients shown in the table below, the amounts of which are expressed as weight percentages of active material (AM).

TABLE-US-00005 A B INGREDIENTS (invention) (Comparative) Thiolactic acid 8 — Thioglycolic acid — 8 PEG-12 Dimethicone 2 2 Polysorbate 20 1 1 2-Amino-2-methylpropan-1-ol 2 2 Water qs 100 qs 100 pH 3.5 ± 0.2 3.5 ± 0.2
2.7 g locks of hair 26 cm long, which have been highly sensitized by bleaching, washed beforehand with a standard shampoo (Pro-Classique from L'Oreal Professionnel), are wound while wet onto curlers according to a standardised protocol.

[0605] The locks are then treated according to the following process: [0606] Application of respectively composition A or composition B, in a proportion of 5.4 g of composition per lock, [0607] Heating of the locks for 15 minutes at a temperature of 40° C. (Climazon infrared lamp), and the locks are covered with a stretchable plastic film, [0608] Rinsing of the locks with water, [0609] Application of an oxidizing composition comprising 2.4% by weight of H.sub.2O.sub.2, relative to the total weight of the oxidizing composition. [0610] The locks are then left to stand for 10 minutes at room temperature (25° C.), [0611] Rinsing of the locks with water and wrung out.

[0612] In order to evaluate the preservation of the integrity of the fibre, the elasticity of the wet hair is evaluated by stretching it on both sides: the more elastic it is, the more it returns to its original shape and its integrity is preserved.

[0613] If the hair breaks after stretching, it is no longer elastic and its integrity has not been preserved.

[0614] The results performed by a trained expert are given below:

TABLE-US-00006 A B (invention) (Comparative) The hair is elastic, it returns The hair breaks quickly to its original shape Integrity is conserved Integrity is not conserved

[0615] We can observe that the locks treated with the composition A (invention) present a better conservation of their integrity than the locks treated with the composition B (comparative).