Improvement of the wash fastness of keratin fibers dyed with oxidative dyes by sealing with chitosan

Abstract

The present invention relates to a method for dyeing keratinous fibers, in particular human hair, comprising the following steps: - Application of a dye (F) to the keratinous fibers, which (F-1) at least one oxidation dye precursor and (F-2) contains at least one oxidizing agent, preferably hydrogen peroxide, and - application of a post-treatment agent (N) to the keratinous fibers, which (N-1) contains at least one chitosan and / or one chitosan derivative.

Description

[0001] The subject matter of the present application is a cosmetic process for dyeing keratinous fibers, in particular human hair, comprising the application of a dyeing agent containing at least one oxidation dye precursor and an oxidizing agent, and the application of a post-treatment agent containing at least one chitosan and / or a chitosan derivative.

[0002] A second object is a process for improving the wash fastness of dyed keratinous fibers which have been dyed by applying a dye containing at least one oxidation dye precursor and an oxidizing agent, wherein a post-treatment agent is applied to the dyed keratinous fibers which contains at least one chitosan and / or a chitosan derivative.

[0003] A third subject is the use of the post-treatment agent (N) to improve the wash fastness of keratinous fibers dyed with a dye containing at least one oxidation dye precursor and an oxidizing agent.

[0004] Altering the shape and color of keratinous material, especially human hair, is an important area of ​​modern cosmetics. Depending on the desired color, professionals are familiar with various dyeing systems for changing hair color. For permanent, intense colorations with good colorfastness and gray coverage, oxidative dyes are typically used. These dyes contain oxidative dye precursors, so-called developer components and coupler components, which react with oxidizing agents such as hydrogen peroxide to form the actual dyes. Oxidative dyes, especially natural shades, are characterized by very long-lasting color results.

[0005] Despite the numerous optimization attempts already undertaken, there is still room for improvement in the colorfastness of oxidatively dyed keratin fibers – especially when dyed in fashionable shades of red or reddish-brown. In particular, the washfastness of red, copper, and reddish-brown shades cannot yet be considered optimal.

[0006] The object of the present invention was therefore to provide oxidative dyes with improved wash fastness. In particular, the wash fastness of the red, copper, and reddish-brown shades produced with oxidative dyes was to be improved.

[0007] Surprisingly, it has now been found that this task can be solved if a conventional dye based on oxidative dyes (F) is first used to color the keratinous fibers and then, in a subsequent step, a post-treatment agent containing at least one chitosan and / or a chitosan derivative is applied.

[0008] A first object of the present invention is a method for dyeing keratinous fibers, in particular human hair, comprising the following steps: - Application of a dye (F) to the keratinous fibers, which contains (F-1) at least one oxidation dye precursor and (F-2) at least one oxidizing agent, preferably hydrogen peroxide, and - Application of a post-treatment agent (N) to the keratinous fibers which (N-1) contains at least one chitosan and / or one chitosan derivative.

[0009] Hair dyed using the above method was characterized by an intense color result with improved wash fastness. Furthermore, the dyed hair was very evenly colored and possessed a beautiful, natural shine without feeling greasy or coated.

[0010] The advantage of the method according to the invention lies primarily in the fact that the user can continue using their usual hair color in their preferred shade and improve its wash fastness by applying the after-treatment product. In particular, if the after-treatment product is applied during the usual hair washing process after shampooing, the user can extend the time between hair colorings. This allows the user to improve the longevity of the hair color with a very quick, easy, and convenient application, and ultimately reduces the frequency of hair coloring. Since the chitosans or chitosane derivatives contained in the after-treatment product are also of natural origin and biodegradable, this form of after-treatment represents a very sustainable and environmentally friendly way of keeping the amount of oxidative dyes used to a minimum.

[0011] In one embodiment, the applicant can therefore either carry out a successive dyeing process in which the keratin fibers are dyed with the oxidative dye (F) and then, preferably after the dye (F) has been rinsed off, treated with the after-treatment agent (N). In this embodiment, the dye (F) and the after-treatment agent (N) are preferably supplied to the user together in an outer package.

[0012] In another embodiment, the user can also treat their already dyed keratin fibers with the post-treatment agent. In this application, the dye can be a standard, commercially available oxidative dye, and the post-treatment can, but does not necessarily have to, be carried out directly after the oxidative dyeing. In this embodiment, the post-treatment agent can also be provided as a separate product with appropriate instructions for use.

[0013] A second object of the present invention is therefore a method for improving the wash fastness of dyed keratinous fibers which have been dyed by applying a dyeing agent (F) containing at least one oxidation dye precursor (F-1) and at least one oxidizing agent (F-2), preferably hydrogen peroxide, wherein a post-treatment agent (N) is applied to the dyed keratinous fibers which contains at least one chitosan and / or a chitosan derivative (N-1).

[0014] In this embodiment, the after-treatment agent can, for example, be formulated in the form of a shampoo, which is preferably used regularly for washing the dyed keratin fibers, or the after-treatment agent can be applied to the dyed and washed keratin fibers after washing the hair, for example in the form of a spray. Keratinous fibers

[0015] Keratinous fibers include hair, wool, and fur. Human hair is particularly often considered a keratinous fiber.

[0016] In the context of this invention, "dyed keratin fibers or hair" refers to keratin fibers that have been previously dyed with an oxidative dye containing at least one oxidation dye precursor and at least one oxidizing agent. "Dyed" in this context means that the coloration produced by the dyes must still be visible. While the coloration may be diminished—for example, by previous washing—it will still be perceived by the user as a color shift compared to the hair's color before dyeing. This color shift can be quantified, for example, by colorimetric measurement of the keratin fibers or hair (measuring the Lab values) before and after dyeing (or dyeing and washing). Dyeing agent (F)

[0017] Before applying the after-treatment agent (N), the keratinous fibers, preferably human hair, are dyed with a dye (F).

[0018] The dye (F) can be applied to moistened or dry keratin fibers. Application can be carried out, for example, using a brush, applicator, or nozzle, or the user can apply it using their gloved hand. After an exposure time of 5 to 60 minutes, preferably 10 to 45 minutes, the dye can be rinsed off with water or with water and a shampoo. Preferably, the dye (F) is rinsed off before the after-treatment agent (N) is applied.

[0019] The oxidative dye (F) is understood to be the ready-to-use dye containing both the oxidation dye precursor(s) (F-1) and the oxidizing agent (F-2), preferably adjusted to an alkaline pH value and thus able to be applied to the keratinous fibers in the form in which it is available. Oxidation dye precursors (F-1) in the dye

[0020] The dye (F) contains at least one oxidation dye precursor (F-1). The oxidation dye precursors include developer-type and coupler-type oxidation dye precursors.

[0021] Suitable developer-type oxidation dye precursors are selected from at least one compound from the group consisting of p-phenylenediamine, p-toluenediamine, 2-(2-hydroxyethyl)-p-phenylenediamine (alternatively also referred to as 2-(2,5-diaminophenyl)ethanol), 2-(1,2-dihydroxyethyl)-p-phenylenediamine, N,N-bis-(2-hydroxyethyl)-p-phenylenediamine, 2-methoxymethyl-p-phenylenediamine, N-(4-amino-3-methylphenyl)-N-[3-(1H-imidazol-1-yl)propyl]amine, N,N'-bis-(2-hydroxyethyl)-N,N'-bis-(4-aminophenyl)-1,3-diamino-propan-2-ol, bis-(2-hydroxy-5-aminophenyl)-methane, 1,3-bis-(2,5-diaminophenoxy)propan-2-ol, N,N'-bis-(4-aminophenyl)-1,4-diazacyclo-heptane, 1,10-bis-(2,5-diaminophenyl)-1,4,7,10-tetraoxadecane, p-aminophenol, 4-amino-3-methylphenol, 4-Amino-2-aminomethylphenol, 4-amino-2-(1,2-dihydroxyethyl)phenol, 4-amino-2-(diethyl-aminomethyl)phenol, 4,5-diamino-1-(2-hydroxyethyl)pyrazole, 2,4,5,6-tetraaminopyrimidine, 4-hydroxy-2,5,6-triaminopyrimidine, 2-Hydroxy-4,5,6-triaminopyrimidine, 2,3-Diamino-6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-one and its physiologically acceptable salts.

[0022] The developer-type oxidation dye precursors (F-1) selected from the group consisting of p-toluenediamine, 2-methoxymethyl-p-phenylenediamine, (2-hydroxyethyl)-p-phenylenediamine, N,N-bis-(2-hydroxyethyl)-p-phenylenediamine, p-phenylenediamine, 4-amino-3-methylphenol, p-aminophenol, 4,5-diamino-1-(2-hydroxyethyl)pyrazole and their physiologically acceptable salts have proven to be particularly suitable for solving the problem according to the invention.

[0023] In a preferred embodiment, the inventive method for dyeing keratin fibers or for improving the wash fastness of the dyed keratin fibers is characterized in that the dyeing agent (F)) contains at least one developer-type oxidation dye precursor (F-1) selected from the group consisting of p-toluenediamine, 2-methoxymethyl-p-phenylenediamine, (2-hydroxyethyl)-p-phenylenediamine, N,N-bis-(2-hydroxyethyl)-p-phenylenediamine, p-phenylenediamine, 4-amino-3-methylphenol, p-aminophenol, 4,5-diamino-1-(2-hydroxyethyl)pyrazole, 2,4,5,6-tetraaminopyrimidine and their physiologically acceptable salts.

[0024] Physiologically compatible salts are the protonated oxidation dyes that possess a physiologically compatible counterion to maintain their electroneutrality. Examples of physiologically compatible counterions include halide ions, sulfate ions, hydrogen sulfate ions, phosphate ions, methosulfate ions, and organic ions such as lactate, citrate, tartrate, and acetate ions. Halide ions, especially chloride and sulfate, are preferred.

[0025] Besonders geeignete Oxidationsfarbstoffvorprodukte vom Kuppler-Typ sind ausgewählt aus der Gruppe, die gebildet wird aus 3-Aminophenol, 5-Amino-2-methylphenol, 3-Amino-2-chlor-6-methylphenol, 2-Hydroxy-4-aminophenoxyethanol, 5-Amino-4-chlor-2-methylphenol, 5-(2-Hydroxyethyl)-amino-2-methylphenol, 2,4-Dichlor-3-aminophenol, 2-Aminophenol, 3-Phenylendiamin, 2-(2,4-Diaminophenoxy)ethanol, 1,3-Bis(2,4-diaminophenoxy)propan, 1-Methoxy-2-amino-4-(2-hydroxyethylamino)benzol, 1,3-Bis(2,4-diaminophenyl)propan, 2,6-Bis(2'-hydroxyethylamino)-1-methylbenzol, 2-({3-[(2-Hydroxyethyl)amino]-4-methoxy-5-methylphenyl}amino)ethanol, 2-({3-[(2-Hydroxyethyl)amino]-2-methoxy-5-methylphenyl}amino)ethanol, 2-({3-[(2-Hydroxyethyl)amino]-4,5-dimethylphenyl}amino)ethanol, 2-[3-Morpholin-4-ylphenyl)amino]ethanol, 3-Amino-4-(2-methoxy-ethoxy)-5-methylphenylamin, 1-Amino-3-bis-(2-hydroxyethyl)aminobenzol, Resorcin, 2-Methylresorcin, 4-Chlorresorcin, 1,2,4-Trihydroxybenzol, 2-Amino-3-hydroxypyridin,3-Amino-2-methylamino-6-methoxypyridine, 2,6-Dihydroxy-3,4-dimethylpyridine, 3,5-Diamino-2,6-dimethoxypyridine, 1-Phenyl-3-methylpyrazol-5-one, 1-Naphthol, 1,5-Dihydroxynaphthalene, 2,7-Dihydroxynaphthalene, 1,7-Dihydroxynaphthalene, 1,8-Dihydroxynaphthalene, 4-Hydroxyindole, 6-Hydroxyindole, 7-Hydroxyindole, 4-Hydroxyindolin, 6-Hydroxyindolin, 7-Hydroxyindolin or mixtures of these compounds or their physiologically acceptable salts.

[0026] In a further preferred embodiment, the inventive process for dyeing keratin fibers or for improving the wash fastness of the dyed keratin fibers is characterized in that the dyeing agent (F) contains at least one coupler-type oxidation dye precursor (F-1) selected from the group consisting of 3-aminophenol, 5-amino-2-methylphenol, 3-amino-2-chloro-6-methylphenol, 2-hydroxy-4-amino-phenoxyethanol, 5-amino-4-chloro-2-methylphenol, 5-(2-hydroxyethyl)-amino-2-methylphenol, 2,4-dichloro-3-aminophenol, 2-aminophenol, 3-phenylenediamine, resorcinol, 2-methylresorcinol, 4-chlororesorcinol, 2-(2,4-diamino-phenoxy)ethanol, 1,3-bis(2,4-diaminophenoxy)propane, 1-Methoxy-2-amino-4-(2-hydroxyethylamino)benzene, 1,3-bis(2,4-diaminophenyl)propane, 2,6-bis(2'-hydroxyethyl-amino)-1-methylbenzene, 1-amino-3-bis-(2-hydroxyethyl)aminobenzene, 2-amino-3-hydroxypyridine, 3-Amino-2-methylamino-6-methoxypyridine, 2,6-dihydroxy-3,4-dimethylpyridine, 3,5-diamino-2,6-dimethoxypyridine, 1-phenyl-3-methylpyrazol-5-one, 1-naphthol, 1,5-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 4-hydroxyindole, 6-hydroxyindole, 7-hydroxyindole, 4-hydroxyindolin, 6-hydroxyindolin, 7-hydroxyindolin and their physiologically acceptable salts.

[0027] A method for dyeing keratinous fibers, especially human hair, is particularly preferred, comprising the following steps: - Application of a dye (F) to the keratinous fibers, which contains: (F-11) at least one developer-type oxidation dye precursor selected from the group consisting of p-toluenediamine, 2-methoxymethyl-p-phenylenediamine, (2-hydroxyethyl)-p-phenylenediamine, N,N-bis-(2-hydroxyethyl)-p-phenylenediamine, p-phenylenediamine, 4-amino-3-methylphenol, p-aminophenol, 4,5-diamino-1-(2-hydroxyethyl)pyrazole and their physiologically acceptable salts, and (F-12) mindestens ein Oxidationsfarbstoffvorprodukt vom Kupplertyp, das ausgewählt ist aus der Gruppe aus 3-Aminophenol, 5-Amino-2-methylphenol, 3-Amino-2-chlor-6-methylphenol, 2-Hydroxy-4-aminophenoxyethanol, 5-Amino-4-chlor-2-methylphenol, 5-(2-Hydroxyethyl)-amino-2-methylphenol, 2,4-Dichlor-3-aminophenol, 2-Aminophenol, 3-Phenylendiamin, Resorcin, 2-Methylresorcin, 4-Chlorresorcin, 2-(2,4-Diamino-phenoxy)ethanol, 1,3-Bis(2,4-di-aminophenoxy)propan, 1-Methoxy-2-amino-4-(2-hydroxyethylamino)benzol, 1,3-Bis(2,4-diamino-phenyl)propan, 2,6-Bis(2'-hydroxyethylamino)-1-methylbenzol, 1-Amino-3-bis-(2-hydroxyethyl)-aminobenzol, 2-Amino-3-hydroxypyridin, 3-Amino-2-methylamino-6-methoxypyridin, 2,6-Dihydroxy-3,4-dimethylpyridin, 3,5-Diamino-2,6-dimethoxypyridin, 1-Phenyl-3-methylpyrazol-5-on, 1-Naphthol, 1,5-Dihydroxynaphthalin, 2,7-Dihydroxynaphthalin, 1,7-Dihydroxynaphthalin, 1,8-Dihydroxynaphthalin, 4-Hydroxyindol, 6-Hydroxyindol, 7-Hydroxyindol, 4-Hydroxy-indolin, 6-Hydroxyindolin,7-Hydroxyindoline and its physiologically acceptable salts, and (F-2) hydrogen peroxide, and, - Application of a post-treatment agent (N) to the keratinous fibers, which contains at least one chitosan and / or one chitosan derivative (N-1).

[0028] The oxidation dye precursors (F-1) (or (F-11) and (F-12)) are preferably used in the dye in specific quantity ranges. Preferably, the dye (F) contains – based on the total weight of the dye (F) – one or more oxidation dye precursors (F-1) in a total amount of 0.0001 to 10.0 wt.%, preferably 0.01 to 7.5 wt.%, more preferably 0.1 to 5.0 wt.%, and most preferably 0.2 to 1.5 wt.%.

[0029] In a further preferred embodiment, the inventive method for dyeing keratin fibers or for improving the wash fastness of the dyed keratin fibers is characterized in that the dyeing agent (F) - based on the total weight of the dyeing agent (F) - contains one or more oxidation dye precursors (F-1) in a total amount of 0.0001 to 10.0 wt.%, preferably 0.01 to 7.5 wt.%, more preferably 0.1 to 5.0 wt.% and most preferably 0.2 to 1.5 wt.%.

[0030] In a further preferred embodiment, the inventive method for dyeing keratin fibers or for improving the wash fastness of the dyed keratin fibers is characterized in that the dyeing agent (F) - based on the total weight of the dyeing agent (F) - contains one or more oxidation dye precursors of the developer type (F-11) and / or of the coupler type (F-12) in a total amount of 0.0001 to 10.0 wt.%, preferably 0.01 to 7.5 wt.%, more preferably 0.1 to 5.0 wt.% and most preferably 0.2 to 1.5 wt.%. Oxidizing agent (F-2) in the dye

[0031] The oxidative dye (F) contains at least one oxidizing agent (F-2). Preferably, hydrogen peroxide and / or one of its solid adsorption products to organic or inorganic compounds is used as the oxidizing agent. Examples of such adsorption products are adsorption products to urea, melamine, and sodium borate.

[0032] In a preferred embodiment, hydrogen peroxide itself is used as an aqueous solution. The concentration of a hydrogen peroxide solution in the composition according to the invention is determined on the one hand by legal requirements and on the other hand by the desired effect; preferably, solutions of 6 to 12 wt% in water are used.

[0033] According to the invention, preferred oxidative dyes (F) contain the oxidizing agent (F-2), in particular hydrogen peroxide, in an amount of 0.1 to 20 wt.%, preferably 1 to 12.5 wt.%, more preferably 2.5 to 10 wt.% and most preferably 3.0 to 8.0 wt.% - based on the total weight of the oxidative dye.

[0034] In a further preferred embodiment, the inventive method for dyeing the keratin fibers or for improving the wash fastness of the dyed keratin fibers is characterized in that the dyeing agent (F) - based on the total weight of the dyeing agent (F) - contains 0.1 to 20 wt.%, preferably 1 to 12.5 wt.%, more preferably 2.5 to 10 wt.% and most preferably 3.0 to 8.0 wt.% hydrogen peroxide. Direct dyes in the dyeing agent (F)

[0035] As a further optional component, the colorants (F) used in the processes according to the invention can also contain at least one direct dye. These are dyes that adhere directly to the hair and do not require an oxidative process to form the color. Direct dyes are typically nitrophenylenediamines, nitroaminophenols, azo dyes, anthraquinones, triarylmethane dyes, or indophenols.

[0036] The direct-acting dyes according to the present invention have a solubility in water (760 mmHg) at 25 °C of more than 0.5 g / L and are therefore not to be considered pigments. Preferably, the direct-acting dyes according to the present invention have a solubility in water (760 mmHg) at 25 °C of more than 1.0 g / L.

[0037] The water solubility of direct-acting dyes can be determined, for example, using the following method. Place 0.1 g of the direct-acting dye into a beaker. Add a magnetic stir bar. Then add 100 ml of water. Heat this mixture to 25 °C on a magnetic stirrer while stirring. Stir for 60 minutes. Afterward, visually inspect the aqueous mixture. If undissolved dye remains, increase the amount of water—for example, in 10 ml increments. Continue adding water until the dye is completely dissolved. If the dye-water mixture cannot be visually assessed due to the high intensity of the dye, filter the mixture. If some undissolved dye remains on the filter paper, repeat the solubility test with a larger amount of water.If 0.1 g of the anionic direct-drawing dye dissolves in 100 ml of water at 25 °C, the solubility of the dye is 1.0 g / L.

[0038] Direct dyes can be divided into cationic, anionic, and nonionic direct dyes. When used in the process according to the invention, particularly with nonionic and cationic dyes (F-1), good color results with outstanding fastness properties were achieved. The greatest improvement in wash fastness was observed when the after-treatment agent (N) was applied to hair that had previously been dyed with at least one nonionic direct dye. Therefore, it is especially preferred if the dye (F) additionally contains at least one nonionic direct dye.

[0039] In a further embodiment, the inventive method for dyeing the keratin fibers or for improving the wash fastness of the dyed keratin fibers is characterized in that the dyeing agent (F) additionally contains at least one direct dye, preferably at least one non-ionic direct dye.

[0040] Suitable nonionic direct-drawing dyes include, for example, nonionic nitro and quinone dyes and neutral azo dyes. Particularly suitable nonionic direct-drawing dyes are those known by their international names, or...Handelsnamen HC Yellow 2, HC Yellow 4, HC Yellow 5, HC Yellow 6, HC Yellow 12, HC Orange 1, Disperse Orange 3, HC Red 1, HC Red 3, HC Red 10, HC Red 11, HC Red 13, HC Red BN, HC Blue 2, HC Blue 11, HC Blue 12, Disperse Blue 3, HC Violet 1, Disperse Violet 1, Disperse Violet 4, Disperse Black 9 bekannten Verbindungen, sowie 1,4-Diamino-2-nitrobenzol, 2-Amino-4-nitrophenol, 1,4-Bis-(2-hydroxyethyl)-amino-2-nitrobenzol, 3-Nitro-4-(2-hydroxyethyl)-aminophenol, 2-(2-Hydroxyethyl)amino-4,6-dinitrophenol, 4-[(2-Hydroxyethyl)amino]-3-nitro-1-methylbenzol, 1-Amino-4-(2-hydroxyethyl)-amino-5-chlor-2-nitrobenzol, 4-Amino-3-nitrophenol, 1-(2'-Ureidoethyl)amino-4-nitrobenzol, 2-[(4-Amino-2-nitrophenyl)amino]-benzoesäure, 6-Nitro-1,2,3,4-tetrahydrochinoxalin, 2-Hydroxy-1,4-naphthochinon, Pikraminsäure und deren Salze, 2-Amino-6-chloro-4-nitrophenol, 4-Ethylamino-3-nitrobenzoesäure und 2-Chlor-6-ethylamino-4-nitrophenol.

[0041] Suitable cationic direct dyes are HC Blue 16, Basic Blue 7, Basic Blue 26, Basic Violet 2 and Basic Violet 14, Basic Yellow 57, Basic Red 76, Basic Blue 16, Basic Blue 347 (Cationic Blue 347 / Dystar), HC Blue No. 16, Basic Blue 99, Basic Brown 16, Basic Brown 17, Yellow 87, Basic Orange 31 and Basic Red 51.

[0042] Suitable anionic direct dyes are the compounds known under the international names or trade names Bromophenol Blue, Tetrabromophenol Blue, Acid Yellow 1, Yellow 10, Acid Yellow 23, Acid Yellow 36, Acid Orange 7, Acid Red 33, Acid Red 52, Pigment Red 57:1, Acid Blue 7, Acid Green 50, Acid Violet 43, Acid Black 1 and Acid Black 52.

[0043] The direct dye(s) can be used in varying amounts in the dye (F) depending on the desired color intensity. Particularly good results were obtained when the dye (F) – based on the total weight of the dye (F) – - containing one or more direct-drawing dyes in a total amount of 0.0001 to 10.0 wt.%, preferably 0.01 to 7.5 wt.%, more preferably 0.1 to 5.0 wt.% and most preferably 0.2 to 1.5 wt.%.

[0044] In a further embodiment, a method according to the invention is characterized in that the dyeing agent (F) - based on the total weight of the dyeing agent (F) - contains one or more direct dyes (F-1) in a total amount of 0.0001 to 10.0 wt.%, preferably 0.01 to 7.5 wt.%, more preferably 0.1 to 5.0 wt.% and most preferably 0.2 to 1.5 wt.%. other ingredients in the dye (F)

[0045] In addition to the direct dye(s) (F-1), the dye (F) may optionally also contain other ingredients.

[0046] Dyeing and lightening processes on keratin fibers typically take place in an alkaline environment. However, to protect the keratin fibers and the skin as much as possible, setting the pH too high is undesirable. Therefore, it is preferred that the pH of the ready-to-use agent be between 6 and 12, particularly between 7 and 10.5. The pH values ​​referred to in the present invention are those measured at a temperature of 22 °C.

[0047] Organic alkalizing agents that can be used according to the invention are preferably selected from alkanolamines of primary, secondary, or tertiary amines with a C2-C6 alkyl backbone bearing at least one hydroxyl group. Particularly preferred alkanolamines are selected from the group consisting of 2-aminoethanol-1-ol (monoethanolamine), 2-amino-2-methylpropan-1-ol, 2-amino-2-methylpropane-1,3-diol, and triethanolamine. However, it has been found during investigations relating to the present invention that further preferred agents according to the invention are characterized by the additional inclusion of an inorganic alkalizing agent. The inorganic alkalizing agent according to the invention is preferably selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, sodium phosphate, potassium phosphate, sodium silicate, potassium silicate, sodium carbonate, and potassium carbonate.Sodium hydroxide and / or potassium hydroxide are particularly preferred. The basic amino acids that can be used as alkalizing agents according to the invention are preferably selected from the group consisting of L-arginine, D-arginine, D / L-arginine, L-lysine, D-lysine, D / L-lysine, with L-arginine, D-arginine, and D / L-arginine being particularly preferred as alkalizing agents according to the invention. Finally, ammonia is another preferred alkalizing agent.

[0048] Furthermore, the coloring agent (F) may also contain other active ingredients, excipients and additives, such as cationic, non-ionic, amphoteric, zwitterionic and / or anionic surfactants, thickening polymers, film-forming polymers, structuring agents such as glucose, maleic acid and lactic acid, hair-conditioning compounds such as phospholipids, for example lecithin and cephalins; perfume oils, dimethyl isosorbide and cyclodextrins; fiber-improving agents, in particular mono-, di- and oligosaccharides such as glucose, galactose, fructose, fruit sugar and lactose; colorants for coloring the agent; anti-dandruff agents such as piroctone olamines, zinc omadine and climbazole; amino acids and oligopeptides; protein hydrolysates of animal and / or plant origin, as well as in the form of their fatty acid condensation products or, where applicable, anionically or cationically modified derivatives; Sunscreen and UV blockers;Active ingredients such as panthenol, pantothenic acid, pantolactone, allantoin, pyrrolidone carboxylic acids and their salts, and bisabolol; polyphenols, in particular hydroxycinnamic acids, 6,7-dihydroxycoumarins, hydroxybenzoic acids, catechins, tannins, leucoanthocyanidins, anthocyanidins, flavanones, flavones, and flavonols; ceramides or pseudoceramides; vitamins, provitamins, and vitamin precursors; plant extracts; fats and waxes such as fatty alcohols, beeswax, montan wax, and paraffins; swelling and penetrating agents such as glycerin, propylene glycol monoethyl ether, carbonates, hydrogen carbonates, guanidines, ureas, and primary, secondary, and tertiary phosphates; opacifying agents such as latex, styrene / PVP, and styrene / acrylamide copolymers; Pearlescent agents such as ethylene glycol mono- and distearate as well as PEG-3 distearate; and propellants such as propane-butane mixtures, N2O, dimethyl ether, CO2 and air.;

[0049] The expert will select these additional substances based on the desired properties of the agent. Regarding further optional components and the amounts of these components used, reference is expressly made to the relevant manuals known to the expert. The additional active ingredients and excipients are preferably used in the preparations according to the invention in amounts of 0.0001 to 25 wt.%, in particular 0.0005 to 15 wt.%, based on the total weight of the respective agent. Medication for aftercare

[0050] Following the application of the oxidative dye (F), the post-treatment agent (N) is applied to the keratin fibers. The post-treatment agent (N) contains at least one chitosan and / or a chitosan derivative (N-1), which forms a uniform and smooth film around the surface of the dyed keratin fibers, thus preventing the dyes formed during the oxidative dyeing process from washing out.

[0051] The post-treatment agent (N) can be applied, for example, to the keratin fibers while they are still damp from the dye wash (F) or to the dried fibers. It is also possible to apply the post-treatment agent (N) to the dyed keratin fibers after washing, either while they are still damp or after they have dried. Chitosans (N-1) in the post-treatment agent (N)

[0052] The post-treatment agent used in the process according to the invention contains as an essential component at least one chitosan or a derivative of chitosan (N-1).

[0053] Chitosan, also known as polyglucosamine or poly-D-glucosamine, is a naturally occurring biopolymer derived from chitin, which is composed of β-1,4-glycosidically linked N-acetylglucosamine residues (specifically, 2-acetamido-2-deoxy-β-D-glucopyranose residues). Like chitin, it is a polyaminosaccharide. Chitosan is produced by deacetylating chitin, resulting in a molecule consisting of approximately 2000 linearly linked 2-amino-2-deoxy-β-D-glucopyranose or glucosamine monomers. Chitosan has the CAS number 9012-76-4.

[0054] Chitosan is preferably produced from chitin, which is found in shellfish or crustaceans. Chitosan is industrially produced from chitin by deacetylation. This can be achieved, for example, using (hot) sodium hydroxide or enzymatically. Both processes are used industrially, but the alkaline method is clearly the most prevalent in terms of volume. The degree of deacetylation can vary considerably: deacetylation can be complete or partial, resulting in a distribution of strongly deacetylated areas alongside weakly deacetylated areas, or a homogeneous deacetylation distribution. Simultaneously, this chemical process can decrease the polymer chain length (depolymerization). The molecular weight of chitosan can range over a wide spectrum, for example, from 20,000 to approximately 5 million g / mol.

[0055] Chitosan derivatives are compounds with a chitosan core structure in which at least some of the existing functional groups have been chemically modified. Chitosan derivatives also possess a poly-D-glucosamine or polyglucosamine structure.

[0056] For example, a chitosan with a molecular weight of 20,000 to 800,000 g / mol is very suitable, preferably 50,000 to 600,000 g / mol, more preferably 80,000 to 450,000 g / mol and most preferably 100,000 to 300,000 g / mol.

[0057] In a further particularly preferred embodiment, a method according to the invention is characterized in that the post-treatment agent (N) contains at least one chitosan and / or one chitosan derivative (N-1) with a molecular weight of 20,000 to 800,000 g / mol, preferably of 50,000 to 600,000 g / mol, more preferably of 80,000 to 450,000 g / mol and most preferably of 100,000 to 300,000 g / mol.

[0058] In a further particularly preferred embodiment, a method according to the invention is characterized in that the post-treatment agent (N) contains at least one chitosan (N-1) with a molecular weight of 20,000 to 800,000 g / mol, preferably of 50,000 to 600,000 g / mol, more preferably of 80,000 to 450,000 g / mol and most preferably of 100,000 to 300,000 g / mol.

[0059] Chitosan with a molecular weight of 100,000 to 300,000 g / mol can be purchased commercially from the company Sigma Aldrich, for example.

[0060] A chitosan with a lower molecular weight of 10,000 to 30,000 g / mol (or Daltons) is, for example, commercially available in pharmaceutical purity from BioLog Heppe (Kraeber). The degree of deacetylation of this chitosan is 88–95%.

[0061] Chitosan in the form of its hydrochloride can be obtained as vegan chitosan from the company Sandream Impact. The hydrochloride of chitosan is a chitosan derivative according to the invention.

[0062] Chitosan 027 is a suitable, commercially available, high-molecular-weight chitosan from the company Polymar, which has a molecular weight of 100,000 - 2,000,000 g / mol.

[0063] It has proven particularly advantageous if the post-treatment agent according to the invention contains the chitosans and / or chitosane derivatives (N-1) in certain quantity ranges. Particularly good results were obtained when the post-treatment agent contained one or more chitosans and / or chitosane derivatives in a total amount of 0.1 to 10.0 wt.%, preferably 0.2 to 8.0 wt.%, more preferably 0.5 to 6.0 wt.%, and most preferably 0.7 to 2.0 wt.%.

[0064] In a further particularly preferred embodiment, a method according to the invention for dyeing the keratinous fibers or for improving the wash fastness of the dyed keratinous fibers is characterized in that the post-treatment agent (N) - based on the total weight of the post-treatment agent (N) - contains one or more chitosans and / or chitosane derivatives (N-1) in a total amount of 0.1 to 10.0 wt.%, preferably 0.2 to 8.0 wt.%, more preferably 0.5 to 6.0 wt.% and most preferably 0.7 to 2.0 wt.%.

[0065] In a further particularly preferred embodiment, a method according to the invention is characterized in that the post-treatment agent (N) - based on the total weight of the post-treatment agent (N) - contains one or more chitosans (N-1) in a total amount of 0.1 to 10.0 wt.%, preferably 0.2 to 8.0 wt.%, more preferably 0.5 to 6.0 wt.% and most preferably 0.7 to 2.0 wt.%. organic and / or inorganic acids (N-2) in the post-treatment agent

[0066] As a further optional component (N-2), the post-treatment agent (N) used in the process according to the invention may contain at least one organic and / or inorganic acid (N-2).

[0067] The use of one or more acids can lower the pH of the post-treatment solution (N), thereby protonating the chitosan completely or partially, thus improving its solubility. Macroscopically, the protonation of chitosan in water is observed as swelling, from which, when the preferred or highly preferred pH is achieved, a particularly uniform and thin film is deposited on the dyed keratin fibers, such as hair. It has been shown that the more uniformly the film forms on the hair, the better its durability. Forming a particularly uniform film has also resulted in dyes with exceptionally good wash fastness. Furthermore, the presence of the acid(s) (N-2) in the post-treatment solution also enables the chitosan to form a particularly thin film on the hair.Comparative studies have shown that a uniformly thin film has better resistance to external mechanical influences.

[0068] Particularly suitable organic acids include, for example, acetic acid, citric acid, succinic acid, tartaric acid, lactic acid, malic acid, malonic acid, maleic acid and benzoic acid.

[0069] Formic acid and propanoic acid are also suitable acids (N-2).

[0070] In a further particularly preferred embodiment, a method according to the invention is therefore characterized in that the post-treatment agent (N) contains one or more organic acids (N-2) from the group consisting of acetic acid, citric acid, succinic acid, tartaric acid, lactic acid, malic acid, malonic acid, maleic acid and benzoic acid.

[0071] Acetic acid dissolves chitosan particularly well and leads to very thin and uniform films; therefore, a post-treatment agent (N) containing acetic acid is particularly preferred.

[0072] In a further explicitly preferred embodiment, a method according to the invention is therefore characterized in that the post-treatment agent (N) contains acetic acid (N-2).

[0073] By using the acid(s) in suitable quantities, the pH of the post-treatment agent can be adjusted to the desired pH range. Particularly thin and uniform films were obtained when the post-treatment agent (N) was adjusted to a pH in the range of 2.0 to 7.5, preferably 3.0 to 7.0, more preferably 3.5 to 6.5, and most preferably 4.0 to 6.0.

[0074] In a further particularly preferred embodiment, a method according to the invention is therefore characterized in that the post-treatment agent (N) has a pH value of 2.0 to 7.5, preferably of 3.0 to 7.0, more preferably of 3.5 to 6.5 and most preferably of 4.0 to 6.0. Water content in the post-treatment agent (N)

[0075] In order to further support the uniform distribution of the film, it has also proven particularly advantageous to adjust the water content of the post-treatment agent (N) to a range of 50.0 to 99.5 wt.%, preferably 65.0 to 99.5 wt.%, more preferably 80.0 to 99.5 wt.% and most preferably 90.0 to 99.5 wt.%.

[0076] In a further particularly preferred embodiment, a method according to the invention is therefore characterized in that the post-treatment agent (N) - based on the total weight of the post-treatment agent (N) - contains 50.0 to 99.5 wt.%, preferably 65.0 to 99.5 wt.%, more preferably 80.0 to 99.5 wt.% and most preferably 90.0 to 99.5 wt.% water (N-3).

[0077] Furthermore, particularly good results were obtained when the post-treatment agent (N) contained water and acids in a specific weight ratio. It has proven particularly advantageous to adjust the weight ratio of the water (N-3) to the acids (N-2) contained in the post-treatment agent (N), i.e., the weight ratio (N-3) / (N-2), to a value of 1000 to 10, preferably 500 to 40, more preferably 200 to 60, and most preferably 150 to 85.

[0078] In a further particularly preferred embodiment, a method according to the invention is therefore characterized in that the weight ratio of the water (N-3) contained in the post-treatment agent (N) to the acids (N-2), i.e. the weight ratio (N-3) / (N-2), is in a value of 1000 to 10, preferably from 500 to 40, more preferably from 200 to 60 and most preferably from 150 to 85. Quantity fraction of components (N-1), (N-2) and (N-3) in the post-treatment agent (N)

[0079] During the work leading to this invention, microscopic images were taken which showed that a thin, uniform film on the keratin fibers possesses particularly good resistance to external influences such as mechanical friction or hair washing. The smoother and more continuous the film, the less surface area it offers to external forces. Once the film is broken in one place, it can be completely removed very quickly by the constant movement of the keratin fibers.

[0080] It was found that the films produced with the post-treatment agent (N) were particularly thin, uniform, and stable when the post-treatment agent consisted largely of components (N-1), (N-2), and (N-3). It is suspected that other components could disrupt the uniformity of the film because they could become embedded in the film, weaken it at that point, or create a point of attack for external forces. For this reason, it is especially preferred that components (N-1), (N-2), and (N-3) are present together in the post-treatment agent (N) in a proportion of at least 90.0 wt.%, preferably at least 93 wt.%, more preferably at least 96 wt.%, and most preferably at least 99 wt.%.

[0081] If the components (N-1), (N-2) and (N-3) together constitute a quantity of at least 90.0 wt.% in the post-treatment compound, then the post-treatment compound consists of - based on its total weight - at least 90 wt% of components (N-1), (N-2) and (N-3). In other words, other substances or ingredients different from (N-1) to (N-3) are present in the post-treatment agent (N) only in a quantity of a maximum of 10 wt%, but preferably in even smaller quantities.

[0082] In a further particularly preferred embodiment, a method according to the invention is therefore characterized in that the post-treatment agent (N) contains the components (N-1), (N-2) and (N-3) together in a quantity of at least 90.0 wt.%, preferably at least 93 wt.%, more preferably at least 96 wt.% and most preferably at least 99 wt.%. No solvent in the post-treatment agent (N)

[0083] Furthermore, it has also proven advantageous if no solvents other than water are added to the post-treatment agent (N). Here too, it was observed that the film produced on the keratin fibers was very thin and uniform when the dye did not contain a solvent from the group consisting of ethanol, isopropanol, 1,2-propylene glycol, 1,3-propanediol, glycerol, 1-butanol, and / or polyethylene glycols.

[0084] In a further particularly preferred embodiment, a process according to the invention is therefore characterized in that the post-treatment agent (N) is essentially free of solvents from the group consisting of ethanol, isopropanol, 1,2-propylene glycol, 1,3-propanediol, glycerol, 1-butanol, phenoxyethanol, benzyl alcohol and / or polyethylene glycols.

[0085] Some raw materials may contain one or more of the aforementioned solvents in small quantities as a minor component, so that when this raw material is to be used, marginal amounts of this solvent will be introduced along with it. However, it has been found that the presence of such small amounts of solvent does not unduly impair film formation.

[0086] In a further particularly preferred embodiment, a process according to the invention is therefore characterized in that the post-treatment agent (N) is essentially free of solvents from the group consisting of ethanol, isopropanol, 1,2-propylene glycol, 1,3-propanediol, glycerol, 1-butanol, phenoxyethanol, benzyl alcohol and polyethylene glycols.

[0087] In a further particularly preferred embodiment, a process according to the invention is therefore characterized in that the post-treatment agent (N) is free of solvents from the group consisting of ethanol, isopropanol, 1,2-propylene glycol, 1,3-propanediol, glycerol, 1-butanol, phenoxyethanol, benzyl alcohol and polyethylene glycols. Ethanol has the Cas number 64-17-5.

[0088] Isopropanol is also alternatively called 2-propanol and has the CAS number 67-63-0. 1,2-Propylene glycol is also alternatively called 1,2-propanediol and has the CAS numbers 57-55-6 [(RS)-1,2-dihydroxypropane], 4254-14-2 [(R)-1,2-dihydroxypropane] and 4254-15-3 [(S)-1,2-dihydroxypropane].

[0089] 1,3-Propanediol or 1,3-dihydroxypropane has the CAS number 504-63-2. Glycerol is alternatively known as 1,2,3-propanetriol and has the CAS number 56-81-5. 1-Butanol can also be called n-butanol or butyl alcohol and has the CAS number 71-36-3.

[0090] Phenoxyethanol has the Cas number 122-99-6.

[0091] Benzyl alcohol is also known as phenylmethanol and has the CAS number 100-51-6.

[0092] Polyethylene glycols according to the present invention are polymers of the general formula C that are liquid at room temperature (25 °C). 2n H 4n+2 O n+1 The repeating unit of the linearly structured polymer is (-CH2-CH2-O-), with a molar mass of approximately 44 g / mol. -1 Chemically, it is a polyether. Polyethylene glycols are therefore understood to be ethylene glycols of the formula (EG), where x represents an integer from 2 to 10000. Viscosity of the post-treatment agent (N)

[0093] The work carried out within the scope of this application has shown that particularly thin films could be formed even when the post-treatment agent (N) itself was low in viscosity and spread quickly and with good spreading action on the keratin material. Therefore, it is further preferred if the post-treatment agent (N) has a viscosity of 10 to 10,000 mPas, preferably 10 to 5,000 mPas, more preferably 100 to 3,000 mPas, and most preferably 100 to 2,000 mPas (22 °C / Brookfield viscometer / spindle 3 / 30 rpm = revolutions per minute).

[0094] In a further particularly preferred embodiment, a method according to the invention for dyeing the keratin fibers or for improving the wash fastness of the dyed keratin fibers is characterized in that the post-treatment agent (N) has a viscosity of 10 to 10,000 mPas, preferably of 10 to 5,000 mPas, more preferably of 100 to 3,000 mPas and most preferably of 100 to 2,000 mPas (22 °C / Brookfield viscometer / spindle 3 / 30 rpm). Pigments in the post-treatment agent (N)

[0095] Optionally, the post-treatment agent (N) used in the process according to the invention can contain at least one pigment. For the purposes of this invention, pigments are understood to be coloring compounds which have a solubility in water at 25 °C of less than 0.5 g / L, preferably less than 0.1 g / L, and even more preferably less than 0.05 g / L. The water solubility can be determined, for example, by the method described below: 0.5 g of the pigment is weighed into a beaker. A magnetic stir bar is added. Then one liter of distilled water is added. This mixture is heated to 25 °C for one hour while stirring on a magnetic stirrer. If undissolved components of the pigment are still visible in the mixture after this period, the solubility of the pigment is below 0.5 g / L.If the pigment-water mixture cannot be visually assessed due to the high intensity of the potentially finely dispersed pigment, the mixture is filtered. If a proportion of undissolved pigment remains on the filter paper, the pigment's solubility is below 0.5 g / L.

[0096] Suitable color pigments can be of inorganic and / or organic origin.

[0097] In a preferred embodiment, a method according to the invention is characterized in that the post-treatment agent (N) contains at least one pigment, preferably at least one pigment from the group consisting of inorganic and / or organic pigments.

[0098] The pigment(s) color the film formed from the chitosans and can thus provide an additional color refreshment or - if desired - also a nuance of the previously oxidatively colored keratin fibers.

[0099] Preferred color pigments are selected from synthetic or natural inorganic pigments. Inorganic color pigments of natural origin can be produced, for example, from chalk, ochre, umber, green earth, burnt sienna, or graphite. Furthermore, black pigments such as iron oxide black, colored pigments such as ultramarine or iron oxide red, as well as fluorescent or phosphorescent pigments can be used as inorganic color pigments.

[0100] Particularly suitable are colored metal oxides, hydroxides and oxide hydrates, mixed-phase pigments, sulfur-containing silicates, silicates, metal sulfides, complex metal cyanides, metal sulfates, chromates and / or molybdates. Especially preferred color pigments are black iron oxide (CI 77499), yellow iron oxide (CI 77492), red and brown iron oxide (CI 77491), manganese violet (CI 77742), ultramarine (sodium aluminum sulfosilicates, CI 77007, Pigment Blue 29), chromium oxide hydrate (CI 77289), iron blue (ferric ferrocyanide, CI 77510) and / or carmine (cochineal).

[0101] Colored pearlescent pigments are also particularly preferred according to the invention. These are typically mica- and / or micaceous and can be coated with one or more metal oxides. Mica belongs to the layered silicates. The most important representatives of these silicates are muscovite, phlogopite, paragonite, biotite, lepidolite, and margarite. To produce the pearlescent pigments in combination with metal oxides, the mica, predominantly muscovite or phlogopite, is coated with a metal oxide.

[0102] As an alternative to natural mica, synthetic mica coated with one or more metal oxides can also be used as a pearlescent pigment. Particularly favored pearlescent pigments are based on natural or synthetic mica and coated with one or more of the aforementioned metal oxides. The color of the respective pigments can be varied by changing the thickness of the metal oxide layer(s).

[0103] In a further preferred embodiment, a method according to the invention is characterized in that the post-treatment agent (N) contains at least inorganic pigment, which is preferably selected from the group consisting of colored metal oxides, metal hydroxides, metal oxide hydrates, silicates, metal sulfides, complex metal cyanides, metal sulfates, bronze pigments and / or colored pigments based on mica or micaceous oxide, which are coated with at least one metal oxide and / or one metal oxychloride.

[0104] In a further preferred embodiment, a method according to the invention is characterized in that the post-treatment agent (N) contains at least one pigment selected from mica- or micaceous-based pigments coated with one or more metal oxides from the group consisting of titanium dioxide (CI 77891), black iron oxide (CI 77499), yellow iron oxide (CI 77492), red and / or brown iron oxide (CI 77491, CI 77499), manganese violet (CI 77742), ultramarines (sodium aluminum sulfosilicates, CI 77007, Pigment Blue 29), chromium oxide hydrate (CI 77289), chromium oxide (CI 77288) and / or iron blue (ferric ferrocyanide, CI 77510).

[0105] Examples of particularly suitable color pigments are available commercially under the trade names Rona®, Colorona®, Xirona®, Dichrona® and Timiron® from Merck, Ariabel® and Unipure® from Sensient, Prestige® from Eckart Cosmetic Colors and Sunshine® from Sunstar.

[0106] Particularly favored color pigments with the trade name Colorona® include, for example: Colorona Copper, Merck, MICA, CI 77491 (IRON OXIDES) Colorona Passion Orange, Merck, Mica, CI 77491 (Iron Oxides), Alumina Colorona Patina Silver, Merck, MICA, CI 77499 (IRON OXIDES), CI 77891 (TITANIUM DIOXIDE) Colorona RY, Merck, CI 77891 (TITANIUM DIOXIDE), MICA, CI 75470 (CARMINE) Colorona Oriental Beige, Merck, MICA, CI 77891 (TITANIUM DIOXIDE), CI 77491 (IRON OXIDES) Colorona Dark Blue, Merck, MICA, TITANIUM DIOXIDE, FERRIC FERROCYANIDE Colorona Chameleon, Merck, CI 77491 (IRON OXIDES), MICA Colorona Aborigine Amber, Merck, MICA, CI 77499 (IRON OXIDES), CI 77891 (TITANIUM DIOXIDE) Colorona Blackstar Blue, Merck, CI 77499 (IRON OXIDES), MICA Colorona Patagonian Purple, Merck, MICA, CI 77491 (IRON OXIDES), CI 77891 (TITANIUM DIOXIDE), CI 77510 (FERRIC FERROCYANIDE) Colorona Red Brown, Merck, MICA, CI 77491 (IRON OXIDES), CI 77891 (TITANIUM DIOXIDE) Colorona Russet, Merck, CI 77491 (TITANIUM DIOXIDE), MICA, CI 77891 (IRON OXIDES) Colorona Imperial Red, Merck, MICA, TITANIUM DIOXIDE (CI 77891), D&C RED NO. 30 (CI 73360) Colorona Majestic Green, Merck, CI 77891 (TITANIUM DIOXIDE), MICA, CI 77288 (CHROMIUM OXIDE GREENS) Colorona Light Blue, Merck, MICA, TITANIUM DIOXIDE (CI 77891), FERRIC FERROCYANIDE (CI 77510) Colorona Red Gold, Merck, MICA, CI 77891 (TITANIUM DIOXIDE), CI 77491 (IRON OXIDES) Colorona Gold Plus MP 25, Merck, MICA, TITANIUM DIOXIDE (CI 77891), IRON OXIDES (CI 77491) Colorona Carmine Red, Merck, MICA, TITANIUM DIOXIDE, CARMINE Colorona Blackstar Green, Merck, MICA, CI 77499 (IRON OXIDES) Colorona Bordeaux, Merck, MICA, CI 77491 (IRON OXIDES) Colorona Bronze, Merck, MICA, CI 77491 (IRON OXIDES) Colorona Bronze Fine, Merck, MICA, CI 77491 (IRON OXIDES) Colorona Fine Gold MP 20, Merck, MICA, CI 77891 (TITANIUM DIOXIDE), CI 77491 (IRON OXIDES) Colorona Sienna Fine, Merck, CI 77491 (IRON OXIDES), MICA Colorona Sienna, Merck, MICA, CI 77491 (IRON OXIDES) Colorona Precious Gold, Merck, Mica, CI 77891 (Titanium dioxide), Silica, CI 77491(Iron oxides), Tin oxide Colorona Sun Gold Sparkle MP 29, Merck, MICA, TITANIUM DIOXIDE, IRON OXIDES, MICA, CI 77891, CI 77491 (EU) Colorona Mica Black, Merck, CI 77499 (Iron oxides), Mica, CI 77891 (Titanium dioxide) Colorona Bright Gold, Merck, Mica, CI 77891 (Titanium dioxide), CI 77491(Iron oxides) Colorona Blackstar Gold, Merck, MICA, CI 77499 (IRON OXIDES)

[0107] Other particularly preferred color pigments with the trade name Xirona® include, for example: Xirona Golden Sky, Merck, Silica, CI 77891 (Titanium Dioxide), Tin Oxide Xirona Caribbean Blue, Merck, Mica, CI 77891 (Titanium Dioxide), Silica, Tin Oxide Xirona Kiwi Rose, Merck, Silica, CI 77891 (Titanium Dioxide), Tin Oxide Xirona Magic Mauve, Merck, Silica, CI 77891 (Titanium Dioxide), Tin Oxide.

[0108] In addition, particularly preferred color pigments with the trade name Unipure® include, for example: Unipure Red LC 381 EM, Sensient CI 77491 (Iron Oxides), Silica Unipure Black LC 989 EM, Sensient, CI 77499 (Iron Oxides), Silica Unipure Yellow LC 182 EM, Sensient, CI 77492 (Iron Oxides), Silica

[0109] In a further embodiment, the post-treatment agent (N) according to the invention can also contain one or more organic pigments.

[0110] The organic pigments according to the invention are correspondingly insoluble organic dyes or color lakes, which may be selected, for example, from the group of nitroso, nitro-azo, xanthene, anthraquinone, isoindolinone, isoindolin, quinacridone, perinone, perylene, diketopyrrolopyorrole, indigo, thioindido, dioxazine, and / or triarylmethane compounds.

[0111] Particularly suitable organic pigments include, for example, carmine, quinacridone, phthalocyanine, sorghum, blue pigments with the Color Index numbers CI 42090, CI 69800, CI 69825, CI 73000, CI 74100, CI 74160, yellow pigments with the Color Index numbers CI 11680, CI 11710, CI 15985, CI 19140, CI 20040, CI 21100, CI 21108, CI 47000, CI 47005, green pigments with the Color Index numbers CI 61565, CI 61570, CI 74260, orange pigments with the Color Index numbers CI 11725, CI 15510, CI 45370, CI 71105, and red pigments with the Color Index Numbers CI 12085, CI 12120, CI 12370, CI 12420, CI 12490, CI 14700, CI 15525, CI 15580, CI 15620, CI 15630, CI 15800, CI 15850, CI 15865, CI 15880, CI 17200, CI 26100, CI 45380, CI 45410, CI 58000, CI 73360, CI 73915 and / or CI 75470.

[0112] In a further particularly preferred embodiment, a process according to the invention is characterized in that the post-treatment agent (N) contains at least one organic pigment, preferably selected from the group consisting of carmine, quinacridone, phthalocyanine, sorghum, blue pigments with the color index numbers CI 42090, CI 69800, CI 69825, CI 73000, CI 74100, CI 74160, yellow pigments with the color index numbers CI 11680, CI 11710, CI 15985, CI 19140, CI 20040, CI 21100, CI 21108, CI 47000, CI 47005, green pigments with the color index numbers CI 61565, CI 61570, CI 74260, and orange pigments with the color index numbers CI 11725, CI 15510, CI 45370, CI 71105, red pigments with the color index numbers CI 12085, CI 12120, CI 12370, CI 12420, CI 12490, CI 14700, CI 15525, CI 15580, CI 15620, CI 15630, CI 15800, CI 15850, CI 15865, CI 15880, CI 17200, CI 26100, CI 45380, CI 45410, CI 58000, CI 73360, CI 73915 and / or CI 75470.

[0113] The organic pigment can also be a paint lake. For the purposes of this invention, the term "paint lake" refers to particles comprising a layer of absorbed dyes, wherein the particle-dye unit is insoluble under the aforementioned conditions. These particles can be, for example, inorganic substrates such as aluminum, silica, calcium borosilicate, calcium aluminum borosilicate, or even aluminum itself.

[0114] For example, alizarin lacquer can be used as a colored lacquer.

[0115] Due to their excellent light and temperature resistance, the use of the aforementioned pigments in the post-treatment agent (N) of the process according to the invention is particularly preferred. Furthermore, it is preferred if the pigments used have a specific particle size. Therefore, according to the invention, it is advantageous if the at least one pigment has an average particle size D. 50 The particle size ranges from 1.0 to 50 µm, preferably from 5.0 to 45 µm, preferably from 10 to 40 µm, and particularly from 14 to 30 µm. The mean particle size D 50 can be determined, for example, using dynamic light scattering (DLS).

[0116] Pigments with a specific shape can also be used to stain keratin fibers. For example, a pigment based on a lamellar and / or lenticular substrate platelet can be used. Furthermore, staining based on a substrate platelet containing a vacuum-metallized pigment is also possible.

[0117] In a further preferred embodiment, a means according to the invention is characterized in that it contains at least one pigment selected from the group consisting of pigments based on a lamellar substrate platelet, pigments based on a lenticular substrate platelet, and vacuum metallized pigments.

[0118] The substrate platelets of this type have an average thickness of at most 50 nm, preferably less than 30 nm, particularly preferably at most 25 nm, for example at most 20 nm. The average thickness of the substrate platelets is at least 1 nm, preferably at least 2.5 nm, particularly preferably at least 5 nm, for example at least 10 nm. Preferred thickness ranges for the substrate platelets are 2.5 to 50 nm, 5 to 50 nm, 10 to 50 nm; 2.5 to 30 nm, 5 to 30 nm, 10 to 30 nm; 2.5 to 25 nm, 5 to 25 nm, 10 to 25 nm; 2.5 to 20 nm, 5 to 20 nm, and 10 to 20 nm. Preferably, each substrate platelet has as uniform a thickness as possible. Due to the small thickness of the substrate platelets, the pigment exhibits particularly high opacity.

[0119] The substrate platelets are preferably monolithic. In this context, monolithic means consisting of a single, closed unit without fractures, layering, or inclusions, although structural changes may occur within the substrate platelets. The substrate platelets are preferably homogeneous, meaning that no concentration gradient exists within the platelets. In particular, the substrate platelets are not layered and do not contain any particles or other distributed particles.

[0120] The size of the substrate platelet can be tailored to the specific application, particularly the desired effect on the keratinous material. Typically, the substrate platelets have a mean maximum diameter of approximately 2 to 200 µm, especially approximately 5 to 100 µm.

[0121] In a preferred embodiment, the aspect ratio, expressed as the ratio of the mean size to the mean thickness, is at least 80, preferably at least 200, more preferably at least 500, and particularly preferably more than 750. The mean size of the uncoated substrate platelets is defined as the d50 value of the uncoated substrate platelets. Unless otherwise specified, the d50 value was determined using a Sympatec Helos instrument with Quixel wet dispersion. For sample preparation, the sample to be tested was pre-dispersed in isopropanol for 3 minutes.

[0122] The substrate plates can be made from any material that can be formed into platelet form.

[0123] They can be of natural origin or synthetically produced. Materials from which the substrate plates can be constructed include, for example, metals and metal alloys, metal oxides, preferably aluminum oxide, inorganic compounds and minerals such as mica and (semi-)precious stones, as well as plastics. Preferably, the substrate plates are composed of metal (alloys).

[0124] Any metal suitable for metallic luster pigments can be used. Such metals include iron and steel, as well as all air- and water-resistant (semi-)metals such as platinum, zinc, chromium, molybdenum, and silicon, and their alloys such as aluminum bronzes and brass. Preferred metals are aluminum, copper, silver, and gold. Preferred substrate platelets are aluminum and brass platelets, with aluminum substrate platelets being particularly preferred.

[0125] Lamellar substrate platelets are characterized by an irregularly structured edge and are also referred to as "cornflakes" due to their appearance.

[0126] Due to their irregular structure, pigments based on lamellar substrate platelets produce a high proportion of scattered light. Furthermore, these pigments do not completely mask the existing color of a keratinous material, and effects similar to natural graying can be achieved.

[0127] Lenticular (lens-shaped) substrate platelets have a generally regular, rounded edge and are also referred to as "silver dollars" due to their appearance. Because of their regular structure, pigments based on lenticular substrate platelets have a high proportion of reflected light.

[0128] Vacuum metallized pigments (VMPs) can be obtained, for example, by releasing metals, metal alloys, or metal oxides from appropriately coated films. They are characterized by a particularly thin substrate platelet thickness in the range of 5 to 50 nm and by a particularly smooth surface with increased reflectivity. Substrate platelets comprising a vacuum metallized pigment are also referred to as VMP substrate platelets within the scope of this application. Aluminum VMP substrate platelets can be obtained, for example, by releasing aluminum from metallized films.

[0129] The substrate plates made of metal or metal alloy can be passivated, for example by anodizing (oxide layer) or chromating.

[0130] Uncoated lamellar, lenticular, and / or VPM substrate platelets, especially those made of metal or metal alloy, reflect incident light to a high degree and produce a light-dark flop. These have proven particularly advantageous for use in post-treatment compounds.

[0131] Suitable pigments based on a lamellar substrate platelet include, for example, the VISIONAIRE series pigments from Eckart.

[0132] Pigments based on a lenticular substrate platelet are available, for example, under the name Alegrace® Gorgeous from the company Schlenk Metallic Pigments GmbH.

[0133] Pigments based on a substrate platelet comprising a vacuum metallized pigment are available, for example, under the name Alegrace® Marvelous or Alegrace® Aurous from Schlenk Metallic Pigments GmbH.

[0134] The pigment(s) are preferably used in certain quantity ranges on average.

[0135] Particularly good results were obtained when the post-treatment agent contained one or more pigments in a total amount of 0.01 to 10.0 wt.%, preferably 0.1 to 5.0 wt.%, more preferably 0.2 to 2.5 wt.% and most preferably 0.25 to 1.5 wt.%.

[0136] In a further particularly preferred embodiment, a method according to the invention is characterized in that the post-treatment agent (N) - based on the total weight of the post-treatment agent (N) - contains one or more pigments in a total amount of 0.01 to 10.0 wt.%, preferably 0.1 to 5.0 wt.%, more preferably 0.2 to 2.5 wt.% and most preferably 0.25 to 1.5 wt.%. Steps in the process

[0137] The process for dyeing keratinous fibers, especially human hair, includes the - Application of a dye (F) to the keratinous fibers, which contains (F-1) at least one oxidation dye precursor and (F-2) at least one oxidizing agent, preferably hydrogen peroxide, and which - Application of a post-treatment agent (N) to the keratinous fibers which (N-1) contains at least one chitosan and / or one chitosan derivative.

[0138] The process for improving the wash fastness of dyed keratinous fibers, which have been dyed by applying a dyeing agent (F) containing at least one oxidation dye precursor (F-1) and at least one oxidizing agent, preferably hydrogen peroxide (F-2), comprises the application of a post-treatment agent (N) to the dyed keratinous fiber, which contains at least one chitosan and / or one chitosan derivative (N-1).

[0139] In both processes, which are basically structured the same, the dye (F) is first applied to the keratinous fibers, and then the post-treatment agent (N) is applied.

[0140] In a further explicitly preferred embodiment, the inventive method for dyeing the keratin fibers or for improving the wash fastness of the dyed keratin fibers is characterized in that the dyeing agent (F) is applied before the post-treatment agent (N).

[0141] The washing out of the oxidatively produced dyes can be reduced or prevented by the application of the after-treatment agent (N). To take advantage of this effect as early as possible, the after-treatment agent (N) is therefore preferably applied either directly after application—and preferably after rinsing—of the dye (F), or before, during, or after the first hair wash. Depending on the user's habits, hair is typically washed every one to four days. The interval between the application of the dye (F) and the application of the after-treatment agent (N) is therefore preferably a maximum of 96 hours, more preferably a maximum of 72 hours, even more preferably a maximum of 48 hours, even more preferably a maximum of 12 hours, and most preferably a maximum of 3 hours. The best results were obtained when the after-treatment agent (N) was applied for the first time before the first wash of the dyed keratin fibers.

[0142] In a further particularly preferred embodiment, a method according to the invention is therefore characterized in that the dyeing agent (F) is applied before the post-treatment agent (N) and that a period of at most 96 hours, preferably at most 72 hours, more preferably at most 48 hours, even more preferably at most 12 hours and most preferably at most 3 hours lies between the application of the dyeing agent (F) and the application of the post-treatment agent (N).

[0143] Since the post-treatment agent (N) is preferably formulated as a water-rich and / or low-viscosity formulation as described above, it can be particularly well sprayed onto the keratinous fibers.

[0144] In a further explicitly preferred embodiment, a method according to the invention is therefore characterized in that the post-treatment agent (N) is sprayed onto the keratinous fibers.

[0145] The post-treatment agent (N) can, for example, be supplied in a dispenser container with a spray valve. A particularly fine distribution of the post-treatment agent (N) can be achieved, for example, with an aerosol spray. Aerosol sprays were particularly popular for a long time due to their ease of use. However, due to the environmental concerns of fluorocarbon propellants and the flammability of, for example, hydrocarbons and dimethyl ether, propellant-free dispenser containers with spray valves have also become increasingly important.

[0146] Such systems have so far found practical applications in the form of balloon pumps for perfume atomization, flexible squeeze bottles, and rigid spray bottles with finger or hand-operated pumps. Propellant-free spray systems also include elastomer pressure spray systems, in which an elastomer pouch within a rigid housing is connected to a spray valve and filled with a liquid product under pressure. The spray pressure energy is stored in the elastomer pouch. Pump spray bottles with finger or hand pumps have achieved the greatest importance to date. These dispenser containers with spray valves are commercially available from various suppliers, for example, transparent glass bottles (75 ml) with a pump atomizer attachment.

[0147] After application, the after-treatment agent (N) can be left to act for a period of, for example, 1 to 60 minutes, preferably 5 to 45 minutes. In principle, the after-treatment agent (N) can be rinsed off after this period. However, a particularly good improvement in wash fastness was achieved when the after-treatment agent (N) was designed as a leave-on product, in which the keratin fibers still covered with the after-treatment agent (N) were dried. Since the after-treatment agent (N) preferably has a high to very high water content, it is advantageous to shorten the drying time by heat treatment.

[0148] In a further explicitly preferred embodiment, a method according to the invention is therefore characterized by heating the keratinous fibers covered with the post-treatment agent (N) to a temperature of more than 40 °C.

[0149] Heating accelerates the evaporation of the water present in the post-treatment agent (N), allowing the chitosan film to form. Since the post-treatment agent is not washed out before drying, this embodiment of the process is a leave-on staining method.

[0150] Heating or heat treatment refers to the process of bringing the keratin material into contact with a heated device, or applying this heated device to or on the keratin material. Furthermore, the keratin material can also be exposed to warm / hot air for heat treatment. Examples of such devices include a hairdryer, a heat cap, a flat iron, a curling iron, or an infrared lamp.

[0151] In a particularly preferred embodiment, a method according to the invention is characterized in that the heating to more than 40 °C is carried out by using a hairdryer, a hair dryer, a heat cap, a flat iron, a curling iron or an infrared lamp.

[0152] Furthermore, it was found that it is preferred if the treatment temperature during the heat treatment is between 40 °C and 210 °C, preferably between 40 °C and 190 °C, more preferably between 45 °C and 170 °C, even more preferably between 45 °C and 100 °C, and most preferably between 50 °C and 80 °C. In other words, it has proven particularly preferred if the heat treatment is carried out with a device that is heated to a temperature of 40 °C to 210 °C, preferably between 40 °C and 190 °C, more preferably between 45 °C and 170 °C, even more preferably between 45 °C and 100 °C, and most preferably between 50 °C and 80 °C.

[0153] In a further particularly preferred embodiment, a method according to the invention is characterized by heating the keratinous fibers covered with the post-treatment agent (N) to a temperature of 40 °C to 210 °C, preferably from 40 °C to 190 °C, more preferably from 45 °C to 170 °C, even more preferably from 45 °C to 100 °C and most preferably from 50 °C to 80 °C.

[0154] The duration of the heat treatment can be adjusted to the selected temperature range. For example, heat treatment can be carried out for a duration of 5 seconds to 60 minutes, preferably from 15 seconds to 45 minutes, more preferably from 15 seconds to 30 minutes, and most preferably from 15 seconds to 15 minutes.

[0155] In the course of the process according to the invention, the keratin fibers can be completely subjected to heat treatment, but the treatment of partial areas of the keratin fibers can also be included. Complete heat treatment of the keratin fibers is preferred, i.e., preferably all keratin fibers to which the post-treatment agent (N) has also been applied are heat treated.

[0156] During heat treatment or heating, the keratin fibers can also be combed or brushed.

[0157] For example, the keratin fibers or the hair, possibly under combs or brushes, can be treated with a hairdryer that blows warm or hot air onto the fibers. This air is preferably between 50 and 80 °C. Alternatively, the keratin material or the hair can be held under an infrared lamp, preferably set to a temperature of 50 to 80 °C. For heat treatment, hair can also be pressed between two appropriately heated plates of a flat iron, which can simultaneously be moved along the hair fiber. The plates of the flat iron can, for example, be set to a temperature of up to 210 °C.

[0158] In a further particularly preferred embodiment, a method according to the invention is characterized in that the heat treatment is carried out by using a hairdryer, a hair dryer, a heat cap, a flat iron, a curling iron or an infrared lamp. Furthermore, a procedure encompassing the following steps is particularly preferred. (1) Applying the dye (F) as previously described to the keratinous fibers, (2) Action of the dye applied in step (1), (3) Rinsing out the dye, (4) Applying the post-treatment agent (N) as previously described to the dyed keratinous fibers, preferably in the form of a spray, (5) Action of the post-treatment agent (N) applied in step (4), and (6) Heating the keratin fibers covered with the post-treatment agent (N) to a temperature above 40 °C.

[0159] In the particularly preferred leave-on method, the after-treatment agent (N) is applied to or sprayed onto the keratin fibers (step (4)), followed by the reaction period (step (5)). During the reaction period, the after-treatment agent (N) is distributed evenly over the keratin fibers. Since the after-treatment agent (N) is no longer rinsed off the keratin fibers in this embodiment, the reaction period cannot be precisely defined, but essentially lasts until the dried after-treatment agent is removed from the keratin fibers (e.g., by shampooing or mechanical abrasion). The reaction period (step (5)) and the heating or drying of the keratin fibers (step (6)) can therefore overlap.According to the invention, the action of the liquid post-treatment agent can, for example, last until the post-treatment agent in step (6) is completely dry, which, depending on the temperature, can take, for example, 5 to 60 minutes. repeated application of the after-treatment agent (N)

[0160] Good improvements in wash fastness were also observed when the after-treatment agent (N) was repeatedly applied to the dyed keratin fibers. Repeated application is conceivable, for example, before, during, or, particularly preferably, after each hair wash. The user can thus wash their hair as usual with shampoo, rinse the shampoo, then apply or spray the after-treatment agent (N) onto the still damp, partially dried, or dry hair, and then dry the hair treated with the after-treatment agent. Application of the after-treatment agent (N) after every second, third, fourth, fifth, or sixth hair wash is also in accordance with the invention. Improved wash fastness

[0161] The previously described post-treatment agents (N) are used to improve the wash fastness of keratin fibers or hair that has been dyed with an oxidative dye (F).

[0162] The wash fastness of an oxidative hair color refers to the color change of a strand of hair dyed with that shade after several washes. This color change can manifest as a shift towards a different shade or as a fading of the color. Both color changes are equally undesirable for the user. Hair colors with good wash fastness do not change color, or only minimally, even after repeated washes.

[0163] For the purposes of the present invention, an improvement in wash fastness means that keratin fibers previously dyed with the oxidative dye (F) retain a higher color intensity after a defined number of hair washes when the after-treatment agent (N) is applied than without the application of the after-treatment agent (N).

[0164] The improvement in wash fastness can be quantified, for example, through colorimetric measurements (measuring the L, a, and b values) and calculating the color difference. The smaller the color difference between the washed and unwashed hair, the better the wash fastness or color retention.

[0165] A third subject matter of the present application is the use of a post-treatment agent (N), as disclosed in detail in the description of the first and second subject matter of the invention, for improving the wash fastness of keratinous fibers dyed with a dye containing at least one oxidation dye precursor (F-1) and at least one oxidizing agent (F-2).

[0166] Regarding the other preferred embodiments of the use according to the invention, what has been said about the methods according to the invention applies mutatis mutantis. Examples 1. Formulations

[0167] The following dyes were produced (all values, unless otherwise stated, are in wt.%): Color cream Colour cream 1 (wt%) brown-orange Colour cream 2 (wt%) light brown Cetearyl alcohol 9,00 9,00 Ceteareth-20 0,60 0,60 Ceteareth-12 0,60 0,60 Coco-glucoside, glyceryl oleate, water (Lamesoft PO 65) 2,00 2,00 Sodium Laureth-6 Carboxylate 10,00 10,00 Sodium myrethsulfate (Texapon K 14 S Special) 2,80 2,80 1-Propanaminium, N,N,N-trimethyl-3-[(1-oxo-2-propenyl)amino]-, chloride, polymer with sodium 2-propenoate 3,75 3,75 Toluene-2,5-diamine sulfate --- 0,20 2,4,5,6-Tetraaminopyrimidine, sulfate 0,22 --- (2-Hydroxyethyl)-p-phenylenediamine, sulfate 0,73 --- 2-Methylresorcin --- 0,06 Resorcin 0,17 - 4-Chlorresorcin - 0,1 m-Aminophenol - 0,06 2-Amino-3-hydroxypyridine 0,15 2-Amino-6-chloro-4-nitrophenol 0,30 0,20 2,7-Dihydroxynaphthalene 0,16 - Vitamin C 0,60 0,60 Hydroxyethane-1,1-diphosphonic acid (60% aqueous solution) 0,20 0,20 Monoethanolamine 6,30 --- Sodium silicate 0,50 0,50 Ammonia (25% aqueous solution) --- 6,00 Water (distilled) ad 100 ad 100 Oxidizing agent preparation (OX) OX (wt%) Dipicolic acid 0,10 Disodium pyrophosphate 0,10 Sodium hydroxide 50% aqueous solution 0,78 Hydroxyethane-1,1-diphosphonic acid (60% aqueous solution) 1,50 Sodium C12-14 alkyl ether sulfate (2 EO) 0,50 Acrylates Copolymer 2,50 Hydrogen peroxide 50% aqueous solution 12,00 Water ad 100

[0168] The following post-treatment agent was produced: Post-treatment agent (N) (N) (wt%) Chitosan (MW = 100,000 - 300,000 g / mol, Sigma Aldrich) 1,0 acetic acid to pH 4.5 Water (distilled) ad 100 2. Application

[0169] The coloring cream 1 and the coloring cream 2 were mixed immediately before application with the oxidizing agent preparation (OX) in a ratio of 1:1 to the ready-to-use coloring agent (F1 and F2, respectively).

[0170] The ready-to-use dyes (F1 = Color Cream 1 + OX) and (F2 = Color Cream 2 + OX) were each applied to strands of hair (Kerling Euronatur hair white, approximately 5 cm long). For this, the hair strands were moistened, then the dye was applied (0.4 g of dye per 1 g of hair strand) and left to process for 30 minutes at 30 °C. Afterwards, the hair strands were rinsed under running water for 1 minute.

[0171] The after-treatment product was filled into a transparent glass bottle (75 ml) with a pump spray attachment, sprayed onto the colored, still towel-damp hair strands (0.4 g after-treatment product per 1 g hair strand) and massaged in.

[0172] After a processing time of 5 minutes, the strands still treated with the after-treatment agent (N) were dried at 50 °C. The hair strands were then measured colorimetrically. 3. Measurement of wash fastness after a single post-treatment

[0173] Following coloring and aftercare, each colored strand was subjected to 6, 12, or 24 manual washes. For each wash, the strand was moistened, then a standard shampoo (Schwarzkopf, Schauma 7 Herbs) was massaged into the strand for 25 seconds (0.25 g of shampoo per gram of hair). The strand was then rinsed with lukewarm tap water for 30 seconds and dried. After 6, 12, and 24 washes, the strands were again measured using colorimetric analysis.

[0174] For comparison, strands of hair were treated with the dye (F1) or (F2) as described above, but were not subjected to any further treatment and were then washed 6, 12 or 24 times respectively.

[0175] The dE value used to assess the color difference is derived from the L*a*b* color measurements taken on the respective strand as follows: dE=[(Li−L0)2+(ai−a0)2+(bi−b0)2]1 / 2 L0, a0 and b0 = measured values ​​of the dyed strand L i , a i and b i = Measurements of the dyed and washed strand

[0176] The higher the dE value, the greater the color difference between the dyed hair and the dyed and washed hair, and the stronger the color change (i.e., the worse the wash fastness).

[0177] HW = Hair washes Comparison, shade brownish-orange (F1 = color cream 1 + OX) coloring without after-treatment L a b dE compared to 0 HW V1 Staining with (F1), no post-treatment, directly after staining (0 HW) 27,95 28,03 23,37 --- V2 Staining with (F1), no post-treatment, 6 HW 35,46 21,21 26,33 10,57 V3 Staining with (F1), no post-treatment, 12 HW 39,06 18,36 22,92 14,74 V4 Staining with (F1), no post-treatment 24 HW 41,48 16,12 21,47 18,13 Invention, shade brown-orange (F1 = color cream 1 + OX) coloring with 1x after-treatment (directly after coloring) L a b dE compared to 0 HW E1 Staining with (F1), post-treatment with (N), directly after staining (0 HW) 27,97 25,74 23,19 --- E2 Staining with (F1), post-treatment with (N), 6 HW 31,59 21,11 24,34 5,99 E3 Staining with (F1), post-treatment with (N), 12 HW 39,06 18,36 22,92 13,32 E4 Staining with (F1) Post-treatment with (N) 24 HW 37,74 16,54 22,79 13,43

[0178] Hair strands dyed in the brown-orange shade (F1) using the inventive method showed improved wash fastness (lower dE value) compared to the dyeing method without post-treatment. This effect was visible after 6 washes (E2 versus V2), after 12 washes (E3 versus V3), and after 24 washes (E4 versus V4). Comparison, shade light brown (F2 = color cream 2 + OX) coloring without after-treatment L a b dE compared to 0 HW V5 Staining with (F2), no post-treatment, directly after staining (0 HW) 30,87 6,98 2,98 --- V6 Staining with (F2), no aftertreatment, 6 HW 41,31 4,79 7,05 11,42 V7 Staining with (F2), no post-treatment, 12 HW 42,61 4,13 9,02 13,51 V8 Staining with (F2), no aftertreatment 24 HW 43,88 3,86 9,59 14,92 Light brown shade (F2 = Color Cream 2 + OX) Coloring with 1x follow-up treatment (directly after coloring) L a b dE compared to 0 HW E5 Staining with (F2), post-treatment with (N), directly after staining (0 HW) 32,86 7,26 4,53 - E6 Staining with (F2), post-treatment with (N), 6 HW 37,99 5,84 6,69 5,74 E7 Staining with (F2), post-treatment with (N), 12 HW 39,42 5,06 8,65 8,05 E8 Staining with (F2), post-treatment with (N), 24 HW 43,88 3,36 9,59 12,59

[0179] Hair strands dyed in the shade light brown (F2) using the inventive method showed improved wash fastness (lower dE value) compared to the dyeing method without post-treatment. This effect was visible after 6 washes (E6 versus V6), after 12 washes (E7 versus V7), and after 24 washes (E8 versus V8).

Claims

[1] Process for dyeing keratin fibres, in particular human hair, comprising the following steps: - application of a dyeing agent (F) to the keratin fibers, which contains (F-1) at least one oxidation dye precursor and (F-2) at least one oxidizing agent, preferably hydrogen peroxide, and - Application of a post-treatment agent (N) to the keratin fibers, which contains (N-1) at least one chitosan and / or a chitosan derivative. [2] Process for improving the wash fastness of dyed keratinic fibers which have been dyed by applying a coloring agent (F) containing at least one oxidation dye precursor (F-1) and at least one oxidizing agent (F-2), preferably hydrogen peroxide, wherein a post-treatment agent (N) is applied to the dyed keratinic fibers which contains at least one chitosan and / or a chitosan derivative (N-1). [3] Method according to claim 1 or 2, characterized by that the colorant (F) contains at least one oxidation dye precursor (F-1) of the developer type which is selected from the group consisting of p-toluenediamine, 2-methoxymethyl-p-phenylenediamine, (2-hydroxyethyl)-p-phenylenediamine, N,N-bis-(2-hydroxyethyl)-p-phenylenediamine, p-phenylenediamine, 4-amino-3-methylphenol, p-aminophenol, 4,5-diamino-1-(2-hydroxyethyl)-pyrazole, 2,4,5,6-tetraaminopyrimidine and their physiologically acceptable salts. [4] Method according to one of claims 1 to 3, characterized by, dass das Färbemittel (F) mindestens ein Oxidationsfarbstoffvorprodukt (F-1) vom Kupplertyp enthält, das ausgewählt ist aus der Gruppe aus 3-Aminophenol, 5-Amino-2-methylphenol, 3-Amino-2-chlor-6-methylphenol, 2-Hydroxy-4-aminophenoxyethanol, 5-Amino-4-chlor-2-methylphenol, 5-(2-Hydroxyethyl)-amino-2-methylphenol, 2,4-Dichlor-3-aminophenol, 2-Aminophenol, 3-Phenylendiamin, Resorcin, 2-Methylresorcin, 4-Chlorresorcin, 2-(2,4-Diamino-phenoxy)ethanol, 1,3-Bis(2,4-diaminophenoxy)propan, 1-Methoxy-2-amino-4-(2-hydroxyethylamino)benzol, 1,3-Bis(2,4-diaminophenyl)propan, 2,6-Bis(2'-hydroxyethyl-amino)-1-methylbenzol, 1-Amino-3-bis-(2-hydroxyethyl)aminobenzol, 2-Amino-3-hydroxy-pyridin, 3-Amino-2-methylamino-6-methoxypyridin, 2,6-Dihydroxy-3,4-dimethylpyridin, 3,5-Diamino-2,6-dimethoxypyridin, 1-Phenyl-3-methylpyrazol-5-on, 1-Naphthol, 1,5-Dihydroxynaphthalin, 2,7-Dihydroxynaphthalin, 1,7-Dihydroxynaphthalin, 1,8-Dihydroxynaphthalin, 4-Hydroxyindol, 6-Hydroxyindol, 7-Hydroxyindol,4-Hydroxyindoline, 6-Hydroxyindoline, 7-Hydroxyindoline and their physiologically acceptable salts. [5] Method according to one of claims 1 to 4, characterized by that the aftertreatment agent (N) contains at least one chitosan and / or one chitosan derivative (N-1) having a molecular weight of 20,000 to 800,000 g / mol, preferably of 50,000 to 600,000 g / mol, more preferably of 80,000 to 450,000 g / mol and most preferably of 100,000 to 300,000 g / mol. [6] Method according to one of claims 1 to 5, characterized by that the aftertreatment agent (N) - based on the total weight of the aftertreatment agent (N) - contains one or more chitosans and / or chitosan derivatives (N-1) in a total amount of 0.1 to 10.0 wt.%, preferably 0.2 to 8.0 wt.%, more preferably 0.5 to 6.0 wt.% and most preferably 0.7 to 2.0 wt.%. [7] Method according to one of claims 1 to 6, characterized bythat the aftertreatment agent (N) contains one or more organic acids (N-2) from the group consisting of acetic acid, citric acid, succinic acid, tartaric acid, lactic acid, malic acid, malonic acid, maleic acid and benzoic acid. [8] Method according to one of claims 1 to 7, characterized by that the aftertreatment agent (N) - based on the total weight of the aftertreatment agent (N) - contains 50.0 to 99.5 wt.%, preferably 65.0 to 99.5 wt.%, more preferably 80.0 to 99.5 wt.% and most preferably 90.0 to 99.5 wt.% water (N-3). [9] Method according to one of claims 1 to 8, characterized by that the aftertreatment agent (N) contains the components (N-1), (N-2) and (N-3) together in a proportion of at least 90.0 wt.%, preferably at least 93.0 wt.%, more preferably at least 96.0 wt.% and most preferably at least 99.0 wt.%. [10] Method according to one of claims 1 to 9, characterized bythat the aftertreatment agent (N) has a viscosity of 10 to 10,000 mPas, preferably of 10 to 5,000 mPas, more preferably of 100 to 3,000 mPas and most preferably of 100 to 2,000 mPas (22 °C / Brookfield viscometer / spindle 3 / 30 rpm). [11] Method according to one of claims 1 to 10, characterized by that the aftertreatment agent (N) contains at least one pigment, preferably at least one pigment from the group of inorganic and / or organic pigments. [12] Method according to one of claims 1 to 11, characterized by that the colorant (F) is applied before the after-treatment agent (N) and that between the application of the colorant (F) and the application of the after-treatment agent (N) there is a period of maximum 96 hours, preferably maximum 72 hours, more preferably maximum 48 hours, even more preferably maximum 12 hours and most preferably maximum 3 hours. [13] Method according to one of claims 1 to 12, characterized by that the after-treatment agent (N) is sprayed onto the keratin fibers. [14] Method according to one of claims 1 to 13, comprising heating the keratin fibers covered with the after-treatment agent (N) to a temperature of more than 40 °C. [15] Use of a post-treatment agent (N) as defined in claims 1 to 14 for improving the washfastness of keratin fibers dyed with a dyeing agent containing at least one oxidation dye precursor (F-1) and at least one oxidizing agent (F-2).