WO2016146225A1 - Hair dyeing method using natural pigments - Google Patents

Abstract

The present invention relates to a method of hair dyeing characterised in that it comprises the steps of successive applications on keratin fibres a) of a first hair dye composition comprising at least one henna, and c) of a second hair dye composition comprising at least one plant extract being preferably indigo, each of said steps being followed by a rinsing step of said fibres; the entire method allowing dyeing to be obtained that benefits from very good retention and depth. The present invention also relates to a hair dyeing kit for implementing the method: said kit contains i) at least one first henna extract, allowing preparation of a first dyeing composition; ii) at least one second plant extract selected from particular plants, which allows preparation of a second dyeing composition; iii) a base and/or an acid; iv) optionally, an applicator brush; and v) optionally, disposable gloves.

Description

 CAPDLLAD3E COLORING PROCESS USING

 NATURAL PIGMENTS

The present patent application claims the priority of the French patent application FR 15/00530 filed on 17/03/2015, which is hereby incorporated by reference.

The present invention relates to the field of hair dyeing and, more specifically, a method for varying the dye intensity of a hair dye without resorting to aggressive chemical agents for the scalp. Nowadays, fashion leads women and men to resort to hair coloring, either to give reflections or shades to the original color of their hair, to change the color completely, or even for the purpose to mask the signs of aging associated with gray hair.

Now, and before addressing the issue of coloring, it is necessary to recall the structure of the hair, whose visible outer part has a cylindrical structure composed of three distinct layers. In the center, we find the marrow (also called medulla), the cortex that surrounds it and gives the hair its natural color and finally the cuticle, which consists of horny plates in the form of scales that partially overlap and which form the outermost layer. Now, there is also a thin layer of fatty acids ensures the natural hydration of the hair. As far as inter-individual variability is concerned, it is the cortex, and more specifically its thickness, that plays a determining role. This thickness can thus vary from 15 (very fine hair) to 170 microns (very thick hair).

As for the natural color of the hair, it results from its pigmentation The pigmentation associated with the natural color of the layer of the cortex is defined by melanin. It can only be modified by intense oxidation or concentrated alkaline solutions. In terms of coloring, we distinguish the permanent coloring (the dyes penetrate into the hair) of the temporary or semi-permanent coloring (deposition of dyes on the surface of the hair).

Permanent coloring uses oxidation bases generally associated with couplers (FR 2729565 B1). These colorless or weakly colored compounds, combined with oxidizing agents provide access to colored compounds that remain trapped inside the hair fiber. This is explained by the fact that under the action of suspended oxidation bases, the swelling of the hair fiber which results in the separation of the scales of the cuticle. Thus open, the cuticle then allows the penetration of precursors. When they have revealed the desired color that depends on the molecule and the exposure time, an appropriate shampoo or cream closes the scales of the cuticle. The variety of oxidizing bases and associated couplers makes it possible to vary the dyeing tones and the color palette. The permanent color is resistant to external aggressions (light, bad weather, washing, perspiration and friction) because the color is protected by the cuticle as are natural melanin pigments. However, the oxidizing agents of the compositions used for permanent coloring can cause allergic reactions in the scalp as well as degradation of the hair fiber.

Temporary or semi-permanent staining uses colored and coloring molecules which have variable affinities with respect to the hair fiber. These colored molecules are chemical compounds of nitro type benzene (US 3,973,900), anthraquinone, nitropyridine, azo (FR 2570946 A1), xanthene, acridine, azine, triarylmethane (FR 2848839 B1). Due to their desorption of the hair fiber and their poor resistance to washing, these compounds have a low dyeing power. On the other hand, the low resistance of the chromophore to light leads to a fading of the color over time.

The colored and coloring molecules can also be natural compounds derived from plants or trees. A list of natural dyes is given in the table on page 12 of application FR 2549721 A1. The hair dyeing method described in this document comprises two steps, the first of which consists of the application of a solution containing no dye while the second stage requires the application of a solution containing the natural dye. However, the method described does not allow to consider all the dyeing, especially on a white hair basis.

There is therefore a real need to develop hair dyeing processes from natural products which make it possible to obtain powerful, stable and resistant to external attack colorations, offering varied and reproducible dyeing shades, regardless of the nature and original color of the hair.

Surprisingly, the inventors have developed a method for qualifying and / or increasing the dye intensity of a hair dye which overcomes the aforementioned drawbacks. Thus, the process of the invention makes it possible to obtain a color palette as well as complete and reproducible tint marks. In addition, the method of the invention is made from 100% natural compounds that do not cause allergic skin reactions or alteration of the hair fiber. Finally, the process of the invention meets the new standards for cosmetic products (Cosmetic Directive 76/768 / EEC and COMMISSION REGULATION (EU) No 358/2014 of 9 April 2014).

Accordingly, a first object of the invention relates to a hair dyeing process characterized in that it comprises the successive steps of: a) application to keratinous fibers of a first dye composition comprising at least henna;

 b) rinsing said fibers, optionally accompanied by washing;

 c) applying, on these same fibers, a second coloring composition comprising at least one plant extract selected from the group comprising indigo, henna, rhapontic, rosemary, birch, reseda, chestnut, logwood, madder, dyer's broom, coreopsis, dyer's sorghum, alfalfa, cochineal, cachou or a mixture of these; and

d) rinsing said fibers, optionally accompanied by washing. In the prior art, manufacturers used metal salts in dye compositions based on plant extracts used as natural pigments to obtain a satisfactory color. The inventors have demonstrated that it is possible to obtain, using the method according to the invention, deep and durable hair colorations, and this despite the absence of metal salts such as sodium picramate in the compositions used.

Preferably, therefore, neither the first nor the second coloring composition of the process according to the invention comprises metal salts, in particular based on lead, silver, copper or even sodium (e.g. sodium picramate). In any event, neither the first nor the second aqueous composition of the process according to the invention comprises sodium picramate.

As a preliminary to the detail of the process, we specify that by keratin fibers, hair is preferably meant. Similarly, we specify that, in the context of the present invention, we speak of natural pigment (s), not for "dyes" as such but to speak of plant extracts having coloring properties.

In connection with step a), and as a follow-up to the above, we speak of henna for dyeing obtained from the powdered leaves of a thorny shrub of the family Lythraceae, which leaves contain a particular molecule (2-hydroxy-1,4-naphthoquinone, called lawsone). Still for step a), the first coloring composition used is an aqueous composition. This first coloring composition may comprise, in addition to henna, one or more plant extracts selected from the group comprising indigo, rhapontic, rosemary, birch, reseda, chestnut, logwood, madder extract, of broom dyers, coreopsis, sorghum dyers, alfalfa, cochineal, cachou or a mixture thereof.

Now, with regard to the specific coloring properties of the process according to the invention, the percentage (weight / weight) of henna of this first coloring composition, relative to the total of the plant extracts present in it, will be at least 50%, preferably greater than or equal to 60%, and in most cases greater than or equal to 75%.

As regards the content of plant extracts of this first coloring composition, it is broadly comprised between 5 and 50%, but it is more generally between 10 and 40%, or even between 10 and 35% with a preference for a content of between 10 and 20%.

This first staining composition is preferably prepared extemporaneously. Indeed, such coloring compositions have a strong tendency to lose their coloring quality over time. Blame it on well-known oxidation mechanisms. Also, is it better to prepare them at the last minute.

This coloring composition can thus be prepared according to methods well known in the art. Generally, the coloring powder comprising henna and optionally other plant extracts is incorporated with stirring with water, which water may have been heated to further facilitate the dissolution of the powder. It is also possible to modify the pH of the water so as to improve the dissolution of the plant extracts. Now, the inventors have been able to demonstrate that, depending on the pH used, the color of the first coloring composition was likely to vary. Thus, it is possible to obtain a first coloring composition which is all the redder as the pH is acidic and, consequently, a "reddening" of the coloration of the keratin fibers obtained at the end of the process according to the invention.

Conversely, the use of a very basic pH makes it possible to obtain a first thinned color composition, corresponding to a "yellowing" of the coloration of the keratin fibers obtained at the end of the process according to the invention.

Also, if the first coloring composition has a pH of, for the total of the invention, between 3 and 12, its pH will depend on the targeted final coloring. More specifically, it touches on a critical aspect of the process according to the invention and that this first dyeing composition provides the "background" of the final coloration of keratin fibers subjected to the process according to the invention. In a first embodiment, the first coloring composition will have a pH of between 3.5 and 8, preferably between 3.5 and 7. Therefore, this composition will provide a "redness" of keratin fibers. In general, this acidification is carried out using common acids such as citric acid or acetic acid.

In a second embodiment, the first coloring composition will have a pH of between 8.5 and 12, preferably between 9 and 11. Therefore, this composition will allow this to obtain a "yellowing" of the same keratinous fibers. Generally speaking, this basification is carried out by means of common bases such as soda.

As for the application, it is also performed using techniques well known in the art. Now, the application time will allow to play on the final coloring. In general, the application time of the first coloring composition is between 15 and 60 minutes, in particular 20 and 50 minutes, more particularly between 30 and 40 minutes.

Still in connection with this application step, the inventors have shown that a hot application makes it possible to intensify the coloring.

Consequently, the application step a) is advantageously carried out at a temperature of between 40 and 55 ° C., preferably at a temperature of the order of 50 ° C.

In connection with the rinsing step b), it is carried out with water, warm preferably, and most simply of the world. As for the washing, it of course corresponds to the use of a surfactant, especially in the form of a shampoo.

In connection with step c) this time, the second staining composition is, here again, an aqueous composition. Now, it differs from the first in that it does not necessarily include henna but at least one plant extract selected from the group consisting of indigo, henna, rhapontic, rosemary, birch, reseda extracts. , chestnut, logwood, madder, broom dyers, corseopsis, dyers' sorghum, alfalfa, cochineal, cachou or a mixture thereof.

Preferably, this second staining composition will also comprise at least indigo. With regard to this second coloring composition and when it comprises indigo, its percentage (weight / weight) of indigo of this second coloring composition relative to the total of the plant extracts present in it is to at least 10%, preferably equal to or greater than 20% and, in the majority of cases, equal to or greater than 25%.

As regards the content of natural pigments of this second coloring composition, this is broadly comprised between 5 and 50%, but is more generally between 20 and 40%, with a preference for a content between 20 and 30%.

As for the first staining composition, the second staining composition is preferably prepared extemporaneously. This coloring composition may be prepared according to methods well known in the art. Generally, the coloring powder preferably comprising indigo and optionally other plant extracts is incorporated with stirring with water, which water may have been heated to further facilitate the dissolution of the powder.

Here again, it is also possible to modify the pH of the water so as to improve the dissolution of the plant extracts. Now, the inventors have been able to demonstrate that, when indigo was used and according to the pH used, the color of the second coloring composition was likely to vary, but above all, the nature of the keratin fiber reflections in the end process.

Thus, and when the second coloring composition comprises indigo, it is possible to obtain keratin fibers with reflections even more yellow that the pH is basic or reflections even redder than the pH is acidic .

Also, if the second coloring composition again has a pH included, for the overall of the invention, between 3 and 12, its pH will depend on the coloration of the targeted highlights. More specifically, we again touch on a critical aspect of the process according to the invention and that this second staining composition makes it possible to obtain the "reflections" associated with the final staining of the keratinous fibers subjected to the process according to the invention.

In a first embodiment, the second coloring composition will have a pH of between 7.5 and 12, preferably between 8.5 and 1 1. Therefore, this composition will make it possible to obtain "yellow" reflections of the same keratinous fibers. Here again, this basification is achieved by means of common bases such as soda.

In a second embodiment, the second coloring composition will have a pH of between 3.0 and 7, preferably between 3.5 and 6.5. Therefore, this composition will provide "red" reflections on keratin fibers. This acidification will be carried out using common acids such as acetic acid or citric acid.

As for the application of this second coloring composition, it is also carried out using techniques well known in the art and similar to those used for the first coloring composition. Now, the application time will allow to play on the final coloration depth. In general, the application time of this second coloring composition is between 15 and 60 minutes, in particular 20 and 50 minutes, more particularly between 30 and 40 minutes.

Still in relation with this application step c), the inventors have also demonstrated that a hot application of this second coloring composition makes it possible to intensify the depth of the reflections of the final coloration of the keratinous fibers. Accordingly, the application step c) is again advantageously carried out at a temperature between 40 and 55 ° C, preferably at a temperature of the order of 50 ° C.

In connection with step d) rinsing, this is performed identically in step b) previously described. In view of the specific properties of the first and second staining composition, it is quite possible to reverse steps a) and c) in order to obtain the same final staining of the keratinous fibers.

Note that in connection with the process according to the invention, it is possible to integrate a wetting step, or even washing, prior to step a)

A second subject of the invention relates to a hair dyeing kit comprising: i) at least one first henna extract, which makes it possible to prepare a first dyeing composition;

 (ii) at least one second plant extract selected from the group consisting of indigo, henna, rhapontic, rosemary, birch, reseda, chestnut, logwood, madder, dyeing broom extracts, corseopsis, sorghum dyers, alfalfa, cochineal, cachou or a mixture thereof, preferably an indigo extract and which makes it possible to prepare a second coloring composition; iii) a base and / or an acid for adapting the pH of the coloring compositions;

 iv) optionally an applicator brush; and

 v) possibly disposable gloves.

The following examples are provided to illustrate the invention and should in no way be considered as a limit to the scope of the invention.

1) Study of the behavior of a henna-based stain

In this first series of experiments, the influence of the application temperature and the pH on the final coloration of 80% gray locks with a henna-based coloring composition was tested.

At first, the locks are wetted with warm tap water and quickly squeezed between two sheets of absorbent paper. At the same time, different coloring compositions are made by mixing 4 grams of henna with 20 ml of water whose pH has been adjusted or not with acetic acid (pH 3.5) or sodium hydroxide (pH 11). . As a result, these compositions are applied to the locks which are then wrapped in stretchable film. A pose of 30min is then performed, either at room temperature or at 50 ° C.

At the end of the protocol, rinsing of the locks is then performed and the coloration obtained is noted.

The results showed that the coloration obtained was much more intense, more coppery or even more opaque when the application of the composition was carried out hot.

In addition, the results also showed that the pH of the formulation has a significant effect on the coloration obtained with an acidification resulting in a redness of the locks and a basification resulting in a slight lightening, or yellowing of the final coloration obtained. 2) Study of the behavior of an indigo-based stain

In this second series of experiments, the influence of the application temperature and the pH on the final coloration of 80% gray wicks was tested with a henna-based coloring composition.

At first, the locks are wetted with warm tap water and quickly squeezed between two sheets of absorbent paper.

Simultaneously, various coloring compositions are produced by mixing 4 grams of indigo with 20 ml of water whose pH has been adjusted or not with acetic acid (pH 3.5) or sodium hydroxide (pH 1). 1). As a result, these compositions are applied to the locks which are then wrapped in stretchable film. A pose of 30min is then performed, either at room temperature or at 50 ° C.

At the end of the protocol, rinsing of the locks is then performed and the coloration obtained is noted. The results showed, as for henna, that the coloration obtained was much more intense, more covering when the application of the composition was carried out hot.

In addition, the results also showed that the pH of the formulation has a significant effect on the reflections of the coloration obtained with a water basification resulting in the presence of yellow reflections and red reflections with water or water. acidified water.

The use of heat also appears once again as important in limiting the variability between two colorations. 3) Realization of a process allowing in two stages, to obtain a wide

 possible range of colorations and having characteristics of appearance and satisfactory behavior

In this third series of experiments, the influence of staining in two successive stages was tested, again modulating the application temperature and the pH on the final staining of 80% gray wicks.

The tests with two-step application were carried out as follows with coloring compositions prepared with 4 g of paste for 20 g of water:

No. Step 1 Step 2 Coloring

Extracts (%) PH Tps ^" PC Extracts pH Tps T ° C Dark Blonde

 (min) (min)

 1 Henna (100) 8 30 50 indigo (100) 6.5 30 50 -

2 Henna (100) 8 30 50 indigo (100) 6.5 60 50 -

3 Henna (100) 6.5 30 50 indigo (100) 6.5 60 50 -

4 Henna (100) 3.5 30 50 indigo (100) 6.5 30 50 -

5 Henna (100) 3.5 30 50 indigo (100) 3.5 30 50 hazelnut

6 Henna (60) + 6.5 30 50 indigo (80) + 6.5 30 50 - Indigo (40) henna (20) 7 Henna (75) + 6.5 30 Ambi indigo (100) 6.5 60 Am

 Indigo (25) ante bia

 nte

 8 Henna (75) + 6.5 30 50 indigo (100) 6.5 60 50 Brown Indigo (25) glossy

9 Henna (75) + 6.5 30 50 indigo (100) 6.5 30 50 - Indigo (25)

 10 Henna (75) + 6.5 30 50 indigo (95) + 6.5 40 50 Indigo Brown (25) logwood (5)

 11 Henna (75) + 6.5 30 50 indigo (95) + 6.5 40 50 Indigo Brown (25) madder (5)

The results showed that the combination of the two staining steps finally resulted in very good intensity, well-covering stains and in addition to a very good reproducibility and stability, and that none of the compositions used contained metal salts. In addition, this stability and reproducibility was significantly improved with the completion of the hot application steps.

Finally, the inventors have been able to develop an innovative dyeing process using no metal salts but with a more than satisfactory result.

Claims

A hair dyeing process characterized in that it comprises the successive steps of:  a) application on keratin fibers of a first coloring composition comprising at least henna;  b) rinsing said fibers, optionally accompanied by washing;  c) applying, on these same fibers, a second coloring composition comprising at least one plant extract selected from the group comprising indigo, henna, rhapontic, rosemary, birch, reseda, chestnut, logwood, madder, dyer's broom, coreopsis, dyer's sorghum, alfalfa, cochineal, cachou or a mixture of these; and  d) rinsing said fibers, optionally accompanied by washing. 2. The method according to claim 1, characterized in that neither the first nor the second coloring composition comprises metal salts, preferably sodium picramate. 3. The method according to any one of claims 1 or 2, characterized in that the percentage (weight / weight) of henna of this first coloring composition relative to the total of the plant extracts present in it will be from minus 50%, preferably greater than or equal to 60%, and in most cases greater than or equal to 75%. 4. The process according to any one of claims 1 to 3, characterized in that the first dyeing composition will have a pH of between: i) 3.5 and 8, preferably 3.5 and 7 for obtaining a reddening of the keratinous fibers, or ii) 8.5 and 12, preferably 9 and 11, to obtain a yellowing of the keratinous fibers. 5. The method according to any one of claims 1 to 4, characterized in that the second coloring composition comprises at least one indigo extract. 6. The process as claimed in claim 5, characterized in that the percentage (weight / weight) of indigo of this second coloring composition relative to the total of the plant extracts present in it is at least 10%, preferably equal to or greater than 20% and in the majority of cases equal to or greater than 25%. 7. The method according to any one of claims 1 to 6, characterized in that the second coloring composition will have a pH of between: i) 7.5 and 12, preferably 8.5 and 11 for obtaining "yellow" reflections on keratinous fibers, or  ii) 3.0 and 7 for obtaining "red" reflections on the keratinous fibers, preferably 3.5 and 6.5 8. The process according to any one of claims 1 to 7, characterized in that step a) and / or c) of application is carried out at a temperature between 40 and 55 ° C, preferably at a temperature of the order of 50 ° C. 9. The method according to any one of claims 1 to 8, characterized in that the time of application of the coloring compositions in step a) and / or c) is between 15 and 60 minutes, in particular of 20 and 50 minutes, even more particularly between 30 and 40 minutes. 10. A hair dye kit comprising: i) at least one first henna extract, which makes it possible to prepare a first coloring composition; At least one second plant extract selected from the group consisting of indigo, henna, rhapontic, rosemary, birch, reseda, chestnut, logwood, madder, dyer's broom, coreopsis, sorghum of dyers, alfalfa, cochineal, cachou or a mixture thereof, preferably an indigo extract and which makes it possible to prepare a second coloring composition; a base and / or an acid for adapting the pH of the coloring compositions; possibly an applicator brush; and possibly disposable gloves