Improvement of the washing fastness of keratin fibers dyed with direct dyes by means of a sealing process using chitosan

Abstract

The invention relates to a method for dyeing keratin fibers, in particular human hair, having the following steps: - applying a dye (F) onto the keratin fibers, said dye containing at least one direct dye (F-1), and - applying a post-treatment agent (N) onto the keratin fibers, said post-treatment agent containing at least one chitosan and / or a chitosan derivative (N-1).

Description

[0001] Improving the washfastness of keratin fibers dyed with direct dyes by sealing with chitosan

[0002] The present application relates to a cosmetic method for dyeing keratin fibers, in particular human hair, comprising the application of a dyeing agent containing at least one direct dye and the application of an aftertreatment agent containing at least one chitosan and / or a chitosan derivative.

[0003] A second subject matter is a method for improving the washfastness of dyed keratin fibers which have been dyed by applying a colorant containing at least one direct dye, wherein a post-treatment agent containing at least one chitosan and / or a chitosan derivative is applied to the dyed keratin fibers.

[0004] A third object is the use of the after-treatment agent (N) for improving the washfastness of keratin fibers that have been dyed with a dye containing at least one direct dye.

[0005] Altering the shape and color of keratinous material, especially human hair, represents an important area of ​​modern cosmetics. Depending on the coloring requirements, hair coloring specialists are familiar with various coloring systems. For permanent, intense colorings with good fastness properties and good gray coverage, oxidation dyes are typically used. Such dyes contain oxidation dye precursors, so-called developer components, and coupler components, which, under the influence of oxidizing agents such as hydrogen peroxide, form the actual dyes. Oxidation dyes are characterized by very long-lasting coloring results.

[0006] When using direct dyes, already fully formed dyes diffuse from the dyeing agent into the hair fiber. Compared to oxidative hair coloring, the colors obtained with direct dyes are less durable and wash out more quickly. Colorations with direct dyes typically remain on the hair for a period of between 5 and 20 washes. Therefore, there is still room for improvement regarding the fastness properties of colorations produced with direct dyes. The object of the present invention was to find a dyeing process based on direct dyes that produces colorations with improved washfastness and improved leveling power. Furthermore, the shine of the colored keratin fibers should be increased.

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

[0008] A first object of the present invention is a process for dyeing keratin fibers, in particular human hair, comprising the following steps:

[0009] - applying a dye (F) to the keratin fibers, which contains at least one direct dye (F-1), and

[0010] - Application of a post-treatment agent (N) to the keratin fibers, which contains at least one chitosan and / or a chitosan derivative (N-1).

[0011] Hair dyed using the above-mentioned method was characterized by an intense color result with improved washfastness. Furthermore, the hair dyed this way was very evenly colored and possessed a beautiful, natural shine without feeling greasy or coated.

[0012] The advantage of the method according to the invention lies primarily in the fact that the user can continue to use their usual colorant in their preferred shade and, by applying the aftercare product, improve its washfastness. Particularly when the aftercare product is applied as part of the usual hair washing routine after shampooing, the user can delay the time until the next hair coloring. This gives the user the opportunity to improve the durability of the colorant with a very quick, simple, and convenient application, and they also need to color their hair less frequently overall. Since the chitosans or chitosan derivatives contained in the aftercare product are also of natural origin and biodegradable, this form of aftercare represents a highly sustainable and environmentally friendly way to keep the amount of dye used as low as possible.

[0013] Within the scope of one embodiment, the applicant can therefore either carry out a successive dyeing process in which they dye the keratin fibers with the dye (F) and then, preferably after the dye (F) has been rinsed out, treat them with the after-treatment agent (N). Within the scope of this embodiment, the dye (F) and the after-treatment agent (N) are preferably provided to the user together in an outer packaging.

[0014] In another embodiment, the user can also treat their already colored keratin fibers with the aftercare product. In this application, the colorant can be a standard, commercially available colorant with direct dyes, and the aftercare can, but does not necessarily have to, be performed immediately after coloring. Within this embodiment, the aftercare product can also be provided as a separate product with appropriate instructions for use.

[0015] A second subject of the present invention is therefore a process for improving the wash fastness of dyed keratinic fibers which have been dyed by using a coloring agent (F) containing at least one direct dye (F-1), wherein a post-treatment agent (N) containing at least one chitosan and / or a chitosan derivative (N-1) is applied to the dyed keratinic fibers.

[0016] Within the scope of this embodiment, the after-treatment agent can be formulated in the form of a shampoo, which is preferably used regularly to wash the colored keratin fibers, or the after-treatment agent can be applied, for example in the form of a spray, to the colored and washed keratin fibers after washing the hair.

[0017] Keratin fibers

[0018] Keratin fibers include hair, wool, and fur. Human hair is particularly preferred as keratin fibers.

[0019] For the purposes of this invention, colored keratin fibers or hair are understood to mean keratin fibers that have previously been colored with a colorant containing at least one direct dye. "Colored" means that the coloration caused by the dyes must still be visible. The coloration produced by the dyes may thus be attenuated—for example, by previous hair washes—but is still perceived by the user as a color shift. The color shift can be quantified, for example, by colorimetric measurement of the keratin fibers (measurement of the Lab values) before and after coloring.

[0020] Dye (F)

[0021] Before applying the aftercare product (N), the keratin fibers, preferably human hair, are colored with a colorant (F). The colorant (F) can be applied to moistened or dry keratin fibers. The application can be carried out using a brush, a brush nozzle, or the user can use their gloved hand. After a contact time of 5 to 60 minutes, preferably 10 to 45 minutes, the colorant can be rinsed out with water or with water and shampoo.

[0022] Direct dyes (F-1) in the dye

[0023] The colorant (F) contains at least one direct dye (F-1). These are dyes that are absorbed directly into the hair and do not require an oxidative process to develop the color. Direct dyes are typically nitrophenylenediamines, nitroaminophenols, azo dyes, anthraquinones, triarylmethane dyes, or indophenols.

[0024] The direct 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 considered pigments. Preferably, the direct dyes according to the present invention have a solubility in water (760 mmHg) at 25°C of more than 1.0 g / L.

[0025] The water solubility of direct dyes can be determined, for example, as follows: 0.1 g of the direct dye is placed in a beaker. A stir bar is attached. Then 100 ml of water is added. This mixture is heated to 25 °C on a magnetic stirrer while stirring. It is stirred for 60 minutes. The aqueous mixture is then visually assessed. If undissolved residues remain, the amount of water is increased – for example, in 10 ml increments. Water is added until the used amount of dye has completely dissolved. If the dye-water mixture cannot be assessed visually due to the high intensity of the dye, the mixture is filtered. If a portion of undissolved dye remains on the filter paper, the solubility test is repeated using a larger amount of water.If 0.1 g of the anionic direct dye dissolves in 100 ml of water at 25 °C, the solubility of the dye is 1.0 g / L.

[0026] Direct dyes can be divided into cationic, anionic, and non-ionic direct dyes. When used in the process according to the invention, good color results with outstanding fastness properties were achieved, particularly with non-ionic and cationic dyes (F-1). The greatest improvement in washfastness was observed when the aftertreatment agent (N) was applied to hair that had previously been colored with at least one cationic direct dye. It is therefore very particularly preferred if the coloring agent (F) contains at least one cationic direct dye. Within the scope of a further embodiment, the process according to the invention is for coloring the keratin fibers orfor improving the washfastness of the dyed keratinic fibers, characterized in that the coloring agent (F) contains at least one direct dye (F-1) from the group of cationic, non-ionic and / or anionic direct dyes, preferably from the group of cationic and / or non-ionic direct dyes, very particularly preferably from the group of cationic direct dyes.

[0027] Therefore, a method for improving the wash fastness of dyed keratin fibers which have been dyed by using a coloring agent (F) containing at least one cationic direct dye (F-1) is also particularly preferred, wherein a post-treatment agent (N) is applied to the dyed keratin fibers which contains at least one chitosan and / or a chitosan derivative (N-1).

[0028] Preferred 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.

[0029] In a further particularly preferred embodiment, a process according to the invention is characterized in that the colorant (F) contains at least one cationic direct dye (F-1) which is selected from the group consisting of 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.

[0030] Dyes containing at least one non-ionic direct dye (F-1) could also be improved with regard to their wash fastness by using the aftertreatment agent (N).

[0031] Suitable non-ionic direct dyes include non-ionic nitro and quinone dyes and neutral azo dyes. Suitable non-ionic direct dyes are those known under the international designations "Dye Dye" and "Dye Dye" respectively.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 1 1 , 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-nitro- benzol, 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-naphtho- chinon, Pikraminsäure und deren Salze, 2-Amino-6-chloro-4-nitrophenol, 4-Ethylamino-3-nitro- benzoesäure und 2-Chlor-6-ethylamino-4-nitrophenol.

[0032] 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.

[0033] The direct dye(s), in particular the cationic direct dye(s), can be used in the colorant (F) in various amounts depending on the desired color intensity. Particularly good results have been obtained when the colorant (F) contains one or more direct 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. %, based on the total weight of the colorant (F).

[0034] In a further embodiment, a process according to the invention is characterized in that the colorant (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. %, based on the total weight of the colorant (F). Other ingredients in the colorant (F)

[0035] In addition to the direct dye(s) (F-1), the colorant (F) may optionally also contain other ingredients.

[0036] Thus, the coloring agent (F) can also contain further active ingredients, auxiliaries and additives, such as, for example, 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 structure-improving active ingredients, in particular mono-, di- and oligosaccharides such as, for example, glucose, galactose, fructose, fructose and lactose; dyes for coloring the agent; anti-dandruff active ingredients such as piroctone olamine, 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, if appropriate, anionically or cationically modified derivatives; Sunscreens and UV blockers;Active ingredients such as panthenol, pantothenic acid, pantolactone, allantoin, pyrrolidinone 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; opacifiers such as latex, styrene / PVP and styrene / acrylamide copolymers; Pearlescent agents such as ethylene glycol mono- and distearate and PEG-3 distearate; as well as propellants such as propane-butane mixtures, N2O, dimethyl ether, CO2 and air.

[0037] 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.

[0038] Aftercare products

[0039] Following the application of the 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 leaching of the direct dyes that have diffused into the keratin fibers.

[0040] The after-treatment agent (N) can, for example, be applied to the keratin fibers that are still damp after washing out the coloring agent (F) or to the dried keratin fibers. It is also possible to apply the after-treatment agent (N) to the still damp or dried keratin fibers after washing the colored keratin fibers. Preferably, the application of the after-treatment agent (N) can also be repeated.

[0041] Chitosans (N-1) in the post-treatment agent (N)

[0042] As an essential component, the post-treatment agent used in the process according to the invention contains at least one chitosan or a derivative of chitosan (N-1).

[0043] Chitosan, also known as polyglusam, poly-D-glucosamine, or polyglucosamine, is a naturally occurring biopolymer derived from chitin, which is composed of ß-1,4-glycosidically linked N-acetylglucosamine residues (more precisely, 2-acetamido-2-deoxy-ß-D-glucopyranose residues), and is thus, like chitin, a polyaminosaccharide. To produce chitosan, chitin is deacetylated, so that the molecule consists of only approximately 2,000 linearly linked 2-amino-2-deoxy-ß-D-glucopyranose or glucosamine monomers. Chitosan has the CAS number 9012-76-4.

[0044] Chitosan is preferably produced from the chitin found in shellfish or crustaceans. Chitosan is industrially obtained from chitin by deacetylation. This can be achieved, for example, using (hot) sodium hydroxide solution or enzymatically. Both processes are used industrially, but the alkaline procedure is clearly the most widely used. The degree of resulting deacetylation can vary considerably: deacetylation can be complete or partial, resulting in a distribution of highly deacetylated regions alongside less deacetylated regions, or a homogeneous deacetylation distribution. At the same time, this chemical intervention can decrease the chain length of the polymer (depolymerization). The molecular weight of chitosan can vary over a wide range, for example, from 20,000 to approximately 5 million g / mol.

[0045] Chitosan derivatives are compounds with a chitosan base structure in which at least some of the functional groups present have been chemically modified. Chitosan derivatives also possess a poly-D-glucosamine or polyglucosamine structure.

[0046] For example, a chitosan with a molecular weight of 20,000 to 800,000 g / mol, 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 is very suitable.

[0047] In a further very particularly preferred embodiment, a process according to the invention is characterized in that the aftertreatment agent (N) contains at least one chitosan and / or a 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 very particularly preferably of 100,000 to 300,000 g / mol.

[0048] In a further very particularly preferred embodiment, a process according to the invention is characterized in that the aftertreatment agent (N) contains at least one chitosan (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 very particularly preferably of 100,000 to 300,000 g / mol.

[0049] Chitosan with a molecular weight of 100,000 to 300,000 g / mol can be purchased commercially from Sigma-Aldrich, for example. Chitosan with a lower molecular weight of 10,000 to 30,000 g / mol (or Daltons) is available in pharmaceutical grade from BioLog Heppe (Kraeber), for example. The degree of deacetylation of this chitosan is 88-95%.

[0050] Chitosan in the form of its hydrochloride can be purchased as vegan chitosan from Sandream Impact. The chitosan hydrochloride is a chitosan derivative according to the invention.

[0051] Chitosan 027 is a suitable, commercially available, high-molecular chitosan from Polymar, which has a molecular weight of 100,000 - 2,000,000 g / mol.

[0052] It has proven particularly advantageous if the post-treatment agent according to the invention contains the chitosan(s) and / or chitosan derivative(s) (N-1) in specific quantity ranges. Particularly good results were obtained when the post-treatment agent contained one or more chitosans and / or chitosan 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.%, based on the total weight of the post-treatment agent.

[0053] Within the scope of a further particularly preferred embodiment, a method according to the invention for dyeing the keratinic fibers or for improving the washfastness of the dyed keratinic fibers is characterized in that the aftertreatment agent (N) - based on the total weight of the aftertreatment agent (N) - contains one or more chitosans and / or chitosan 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.%.

[0054] In a further particularly preferred embodiment, a process according to the invention is characterized in that the aftertreatment agent (N) - based on the total weight of the aftertreatment agent (N) - contains one or more chitosans 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 aftertreatment agent

[0055] As a further optional component (N-2), the post-treatment agent (N) used in the process according to the invention can contain at least one organic and / or inorganic acid (N-2). By using one or more acids, the pH of the post-treatment agent (N) can be lowered, whereby the chitosan is completely or partially profaned and dissolves more easily. Macroscopically, the protonation of the chitosan in water is perceived as swelling, from which, upon adjustment of the preferred or particularly preferred pH, a particularly uniform and thin film is deposited on the dyed keratin fibers such as hair. It has been shown that the more uniform the film forms on the hair, the better the durability of the film. By forming a particularly uniform film, dyeings with particularly good washfastness could also be obtained.Furthermore, the presence of the acid(s) (N-2) in the after-treatment agent also allows the chitosan to form a particularly thin film on the hair. Comparative studies have shown that a uniformly thin film offers better resistance to external mechanical influences.

[0056] Particularly suitable organic acids include acetic acid, citric acid, succinic acid, tartaric acid, lactic acid, malic acid, malonic acid, maleic acid and benzoic acid.

[0057] Formic acid and propanoic acid are also suitable acids (N-2).

[0058] In a further particularly preferred embodiment, a process according to the invention is therefore characterized in that 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.

[0059] Acetic acid dissolves chitosan particularly well and leads to particularly thin and uniform films, therefore a post-treatment agent (N) containing acetic acid is particularly preferred.

[0060] Within the scope of a further explicitly particularly preferred embodiment, a process according to the invention is therefore characterized in that the aftertreatment agent (N) contains acetic acid (N-2).

[0061] By using the acid(s) in appropriate amounts, 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.

[0062] In a further particularly preferred embodiment, a process according to the invention is therefore characterized in that the aftertreatment agent (N) has a pH 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.

[0063] Water content in the post-treatment agent (N)

[0064] In order to further support the uniform distribution of the film, it has also been found to be particularly advantageous to adjust the water content of the aftertreatment 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.%.

[0065] In a further particularly preferred embodiment, a process according to the invention is therefore characterized in 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 very particularly preferably 90.0 to 99.5 wt.% water (N-3).

[0066] Furthermore, particularly good results were also obtained when the post-treatment agent (N) contained water and acids in a specific weight ratio. It has been found to be particularly preferable to set 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), to a value of 1000 to 10, preferably 500 to 40, more preferably 200 to 60, and most preferably 150 to 85.

[0067] In a further particularly preferred embodiment, a process according to the invention is therefore characterized in that the weight ratio of the water (N-3) contained in the aftertreatment agent (N) to the acids (N-2), ie the weight ratio (N-3) / (N-2), is from 1000 to 10, preferably from 500 to 40, more preferably from 200 to 60 and most preferably from 150 to 85.

[0068] Amount of components (N-1), (N-2) and (F-3) in the aftertreatment agent (N)

[0069] As part of the work leading to this invention, microscopic images were taken that showed that a thin, uniform film on the keratin fibers exhibits particularly good resistance to external influences such as mechanical friction or hair washing. The smoother and more cohesive the film, the less surface area it has to resist external forces. Once the film has been broken at one point, it can be completely removed very quickly due to the constant movement of the keratin fibers.

[0070] It was found that the films produced with the aftertreatment agent (N) were particularly thin, uniform, and stable when the aftertreatment agent consisted largely of components (N-1), (N-2), and (N-3). It is suspected that additional components could impair the uniformity of the film by embedding themselves in the film, weakening the film at this point, or forming a surface vulnerable to external forces. For this reason, it is particularly preferred for components (N-1), (N-2), and (N-3) to be present together in the aftertreatment agent (N) in a proportion of at least 90.0% by weight, preferably at least 93% by weight, more preferably at least 96% by weight, and most preferably at least 99% by weight.

[0071] If components (N-1), (N-2), and (N-3) together constitute a proportion of at least 90.0 wt.% in the post-treatment agent (N), then the post-treatment agent (N) consists of at least 90 wt.% of components (N-1), (N-2), and (N-3) based on its total weight. In other words, in this case, other substances or ingredients other than (N-1) to (N-3) are only contained in the post-treatment agent (N) in a proportion of a maximum of 10 wt.%, but preferably in even smaller proportions.

[0072] In a further particularly preferred embodiment, a process according to the invention is therefore characterized in 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 wt.%, more preferably at least 96 wt.% and most preferably at least 99 wt.%.

[0073] No solvents in the post-treatment agent (N)

[0074] Furthermore, it has also proven preferable if no solvents other than water are added to the after-treatment agent (N). Here, too, it was observed that the film produced on the keratin fibers was very thin and uniform when the colorant did not contain any solvent from the group consisting of ethanol, isopropanol, 1,2-propylene glycol, 1,3-propanediol, glycerin, 1-butanol, and / or polyethylene glycols.

[0075] In a further particularly preferred embodiment, a process according to the invention is therefore characterized in that the aftertreatment agent (N) is substantially 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.

[0076] Some raw materials may contain one or more of the above-mentioned solvents in small amounts as a minor component, so that if this raw material is to be used, marginal amounts of this solvent are introduced. However, it has been found that the presence of such small amounts of solvent does not unduly impair film formation. In a further particularly preferred embodiment, a process according to the invention is therefore characterized in that the aftertreatment 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.

[0077] In a further very particularly preferred embodiment, a process according to the invention is therefore characterized in that the aftertreatment agent (N) is free from solvents from the group consisting of ethanol, isopropanol, 1,2-propylene glycol, 1,3-propanediol, glycerol, 1-butanol, phenoxyethanol, benzyl alcohol and polyethylene glycols.

[0078] Ethanol has the Cas number 64-17-5.

[0079] Isopropanol is also known as 2-propanol and has the CAS number 67-63-0.

[0080] 1,2-Propylene glycol is alternatively also 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],

[0081] 1,3-Propanediol or 1,3-Dihydroxypropane has the CAS number 504-63-2.

[0082] Glycerin is also known as 1,2,3-propanetriol and has the CAS number 56-81-5. 1-Butanol can also be known as n-butanol or butyl alcohol and has the CAS number 71-36-3.

[0083] Phenoxyethanol has the Cas number 122-99-6.

[0084] Benzyl alcohol is also known as phenylmethanol and has the CAS number 100-51-6.

[0085] Polyethylene glycols in the sense of the present invention are liquid polymers at room temperature (25 °C) of the general molecular formula C2nH4n+2O n +i. The repeating unit of the linear polymer is (-CH2-CH2-O-), with a molar mass of about 44 g mol -1 Chemically, it is a polyether. Polyethylene glycols are therefore ethylene glycols of the formula (EG) where x is an integer from 2 to 10000.

[0086] Viscosity of the post-treatment agent (N)

[0087] The work conducted within the scope of this application has shown that particularly thin films could be formed even when the post-treatment agent (N) was inherently thin and distributed 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).

[0088] Within the scope of a further particularly preferred embodiment, a method according to the invention for dyeing the keratinous fibers or for improving the washfastness of the dyed keratinous fibers is characterized in that 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 very particularly preferably of 100 to 2,000 mPas (22 °C / Brookfield viscometer / spindle 3 / 30 rpm).

[0089] Pigments in the aftertreatment agent (N)

[0090] Optionally, the post-treatment agent (N) used in the process according to the invention can contain at least one pigment. Pigments within the meaning of the present invention are understood to mean color-imparting compounds which have a solubility in water at 25°C of less than 0.5 g / L, preferably less than 0.1 g / L, even more preferably less than 0.05 g / L. The water solubility can be determined, for example, using the method described below: 0.5 g of the pigment is weighed into a beaker. A 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 finely dispersed pigment, the mixture is filtered. If a portion of undissolved pigment remains on the filter paper, the pigment's solubility is below 0.5 g / L.

[0091] Suitable color pigments can be of inorganic and / or organic origin.

[0092] In a preferred embodiment, a process according to the invention is characterized in that the aftertreatment agent (N) contains at least one pigment, preferably at least one pigment from the group of inorganic and / or organic pigments.

[0093] The pigment(s) color the film formed from the chitosans and can thus provide additional color refreshment or - if desired - also a nuance of the keratin fibers previously colored with a direct dye.

[0094] Preferred color pigments are selected from synthetic or natural inorganic pigments. Inorganic color pigments of natural origin can be made from chalk, ochre, umber, green earth, burnt sienna, or graphite, for example. Other inorganic color pigments that can be used include black pigments such as iron oxide black, colored pigments such as ultramarine or iron oxide red, as well as fluorescent or phosphorescent pigments.

[0095] 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. Particularly 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), ultramarines (sodium aluminum sulfosilicates, CI 77007, Pigment Blue 29), chromium oxide hydrate (CI 77289), iron blue (ferric ferrocyanide, CI 77510), and / or carmine (cochineal).

[0096] Also particularly preferred color pigments according to the invention are colored pearlescent pigments. These are typically based on mica and / or mica and can be coated with one or more metal oxides. Mica belongs to the class of layered silicates. The most important representatives of these silicates are muscovite, phlogopite, paragonite, biotite, lepidolite, and margarite. To produce pearlescent pigments in combination with metal oxides, the mica, predominantly muscovite or phlogopite, is coated with a metal oxide.

[0097] As an alternative to natural mica, synthetic mica, optionally coated with one or more metal oxides, can also be used as a pearlescent pigment. Particularly preferred 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 varying the layer thickness of the metal oxide(s).

[0098] In a further preferred embodiment, a process according to the invention is characterized in that the aftertreatment agent (N) contains at least one inorganic pigment, which is preferably selected from the group 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 mica, which are coated with at least one metal oxide and / or one metal oxychloride.

[0099] In a further preferred embodiment, a process according to the invention is characterized in that the aftertreatment agent (N) contains at least one pigment which is selected from mica- or mica-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).

[0100] Examples of particularly suitable color pigments are commercially available 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.

[0101] Particularly preferred color pigments with the trade name Colorona® are, for example:

[0102] Colorona Copper, Merck, MICA, CI 77491 (IRON OXIDES)

[0103] Colorona Passion Orange, Merck, Mica, CI 77491 (Iron Oxides), Alumina

[0104] Colorona Patina Silver, Merck, MICA, CI 77499 (IRON OXIDES), CI 77891 (TITANIUM DIOXIDE)

[0105] Colorona RY, Merck, CI 77891 (TITANIUM DIOXIDE), MICA, CI 75470 (CARMINE)

[0106] Colorona Oriental Beige, Merck, MICA, CI 77891 (TITANIUM DIOXIDE), CI 77491 (IRON OXIDES)

[0107] Colorona Dark Blue, Merck, MICA, TITANIUM DIOXIDE, FERRIC FERROCYANIDE

[0108] Colorona Chameleon, Merck, CI 77491 (IRON OXIDES), MICA

[0109] Colorona Aborigine Amber, Merck, MICA, CI 77499 (IRON OXIDES), CI 77891 (TITANIUM DIOXIDE)

[0110] Colorona Blackstar Blue, Merck, CI 77499 (IRON OXIDES), MICA

[0111] Colorona Patagonian Purple, Merck, MICA, CI 77491 (IRON OXIDES), CI 77891 (TITANIUM

[0112] DIOXIDE), CI 77510 (FERRIC FERROCYANIDE)

[0113] Colorona Red Brown, Merck, MICA, CI 77491 (IRON OXIDES), CI 77891 (TITANIUM DIOXIDE)

[0114] Colorona Russet, Merck, CI 77491 (TITANIUM DIOXIDE), MICA, CI 77891 (IRON OXIDES)

[0115] Colorona Imperial Red, Merck, MICA, TITANIUM DIOXIDE (CI 77891), D&C RED NO. 30 (CI 73360)

[0116] Colorona Majestic Green, Merck, CI 77891 (TITANIUM DIOXIDE), MICA, CI 77288 (CHROMIUM OXIDE GREENS)

[0117] Colorona Light Blue, Merck, MICA, TITANIUM DIOXIDE (CI 77891), FERRIC FERROCYANIDE (Cl 77510)

[0118] Colorona Red Gold, Merck, MICA, Cl 77891 (TITANIUM DIOXIDE), Cl 77491 (IRON OXIDES)

[0119] Colorona Gold Plus MP 25, Merck, MICA, TITANIUM DIOXIDE (Cl 77891), IRON OXIDES (Cl 77491)

[0120] Colorona Carmine Red, Merck, MICA, TITANIUM DIOXIDE, CARMINE

[0121] Colorona Blackstar Green, Merck, MICA, Cl 77499 (IRON OXIDES)

[0122] Colorona Bordeaux, Merck, MICA, Cl 77491 (IRON OXIDES)

[0123] Colorona Bronze, Merck, MICA, Cl 77491 (IRON OXIDES)

[0124] Colorona Bronze Fine, Merck, MICA, Cl 77491 (IRON OXIDES)

[0125] Colorona Fine Gold MP 20, Merck, MICA, Cl 77891 (TITANIUM DIOXIDE), Cl 77491 (IRON OXIDES) Colorona Sienna Fine, Merck, Cl 77491 (IRON OXIDES), MICA

[0126] Colorona Sienna, Merck, MICA, Cl 77491 (IRON OXIDES)

[0127] Colorona Precious Gold, Merck, Mica, Cl 77891 (Titanium dioxide), Silica, Cl 77491 (Iron oxides), Tin oxide

[0128] Colorona Sun Gold Sparkle MP 29, Merck, MICA, TITANIUM DIOXIDE, IRON OXIDES, MICA, Cl 77891 , Cl 77491 (EU)

[0129] Colorona Mica Black, Merck, Cl 77499 (Iron oxides), Mica, Cl 77891 (Titanium dioxide)

[0130] Colorona Bright Gold, Merck, Mica, Cl 77891 (Titanium dioxide), Cl 77491 (Iron oxides)

[0131] Colorona Blackstar Gold, Merck, MICA, Cl 77499 (IRON OXIDES)

[0132] Weiterhin besonders bevorzugte Farbpigmente mit der Handelsbezeichnung Xirona® sind beispielsweise:

[0133] Xirona Golden Sky, Merck, Silica, CI 77891 (Titanium Dioxide), Tin Oxide

[0134] Xirona Caribbean Blue, Merck, Mica, CI 77891 (Titanium Dioxide), Silica, Tin Oxide

[0135] Xirona Kiwi Rose, Merck, Silica, CI 77891 (Titanium Dioxide), Tin Oxide

[0136] Xirona Magic Mauve, Merck, Silica, CI 77891 (Titanium Dioxide), Tin Oxide.

[0137] In addition, particularly preferred color pigments with the trade name Unipure® are, for example:

[0138] Unipure Red LC 381 EM, Sensient CI 77491 (Iron Oxides), Silica

[0139] Unipure Black LC 989 EM, Sensient, CI 77499 (Iron Oxides), Silica

[0140] Unipure Yellow LC 182 EM, Sensient, CI 77492 (Iron Oxides), Silica

[0141] In a further embodiment, the aftertreatment agent (N) according to the invention may also contain one or more organic pigments

[0142] The organic pigments according to the invention are correspondingly insoluble, organic dyes or lakes which can be selected, for example, from the group of nitroso, nitro-azo, xanthene, anthraquinone, isoindolinone, isoindoline, quinacridone, perinone, perylene, diketopyrrolopyorrole, indigo, thioindido, dioxazine and / or triarylmethane compounds.

[0143] Particularly suitable organic pigments are, 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 1 1710, 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 1 1725, 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, Cl 15800, Cl 15850, Cl 15865, Cl 15880, Cl 17200, Cl 26100, Cl 45380, Cl 45410, Cl 58000, Cl 73360, Cl 73915 and / or Cl 75470.

[0144] In a further particularly preferred embodiment, a process according to the invention is characterized in that the aftertreatment agent (N) contains at least one organic pigment which is 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 1 1680, 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 C1 11725, CI 15510, CI 45370, CI 71 105, 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.

[0145] The organic pigment can also be a colored lake. For the purposes of the invention, the term colored lake refers to particles comprising a layer of absorbed dyes, the particle-dye unit being insoluble under the aforementioned conditions. The particles can be, for example, inorganic substrates, which can be aluminum, silica, calcium borosilicate, calcium aluminum borosilicate, or even aluminum.

[0146] Alizarin lake, for example, can be used as a colored varnish.

[0147] Due to their excellent light and temperature stability, the use of the aforementioned pigments in the aftertreatment agent (N) is very particularly preferred. Furthermore, it is preferred if the pigments used have a specific particle size. It is therefore advantageous according to the invention if the at least one pigment has an average particle size D50 of 1.0 to 50 pm, preferably of 5.0 to 45 pm, more preferably of 10 to 40 pm, in particular of 14 to 30 pm. The average particle size D50 can be determined, for example, using dynamic light scattering (DLS).

[0148] Pigments with a specific shape can also be used to color the keratin fibers. For example, a pigment based on a lamellar and / or lenticular substrate plate can be used. Furthermore, coloring based on a substrate plate containing a vacuum-metallized pigment is also possible.

[0149] In a further preferred embodiment, an agent according to the invention is characterized in that it contains at least one pigment which is selected from the group of pigments based on a lamellar substrate platelet, pigments based on a lenticular substrate platelet and vacuum metallized pigments.

[0150] The substrate platelets of this type have an average thickness of at most 50 nm, preferably less than 30 nm, more 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, more preferably at least 5 nm, for example at least 10 nm. Preferred ranges for the thickness of 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. Each substrate platelet preferably has a thickness that is as uniform as possible. Due to the low thickness of the substrate platelets, the pigment has particularly high hiding power.

[0151] The substrate platelets are preferably monolithic in structure. Monolithic in this context means consisting of a single, closed unit without fractures, stratification, or inclusions, although structural changes may occur within the substrate platelets. The substrate platelets are preferably homogeneous in structure, meaning that no concentration gradient occurs within the platelets. In particular, the substrate platelets are not layered and do not contain any particles or particles distributed within them.

[0152] The size of the substrate platelet can be tailored to the specific application, especially the desired effect on the keratin material. Typically, the substrate platelets have an average diameter of approximately 2 to 200 pm, particularly approximately 5 to 100 pm.

[0153] In a preferred embodiment, the aspect ratio, expressed as the ratio of the average size to the average thickness, is at least 80, preferably at least 200, more preferably at least 500, and particularly preferably more than 750. The average size of the uncoated substrate platelets is understood to be the d50 value of the uncoated substrate platelets. Unless otherwise stated, the d50 value was determined using a Sympatec Heios device with Quixel wet dispersion. For sample preparation, the sample to be tested was predispersed in isopropanol for 3 minutes.

[0154] The substrate platelets can be made of any material that can be formed into platelets.

[0155] They can be of natural origin or synthetically produced. Materials from which the substrate platelets can be constructed include metals and metal alloys, metal oxides, preferably aluminum oxide, inorganic compounds and minerals such as mica and (semi-)precious stones, as well as plastics. The substrate platelets are preferably made of metal alloys.

[0156] Any metal suitable for metallic luster pigments can be considered. Such metals include iron and steel, as well as all air- and water-resistant (semi)metals such as platinum, zinc, chromium, molybdenum, and silicon, as well as their alloys such as aluminum bronze and brass. Preferred metals are aluminum, copper, silver, and gold. Preferred substrate platelets are aluminum platelets and brass platelets, with aluminum platelets being particularly preferred.

[0157] Lamellar substrate platelets are characterized by an irregularly structured edge and are also called "cornflakes" due to their appearance.

[0158] Due to their irregular structure, pigments based on lamellar substrate platelets generate a high degree of scattered light. Furthermore, pigments based on lamellar substrate platelets do not completely cover the existing color of a keratinous material, and effects similar to natural graying can be achieved, for example.

[0159] Lenticular (= lens-shaped) substrate platelets have a generally regular, round edge and are also called "silver dollars" due to their appearance. Due to their regular structure, the proportion of reflected light predominates in pigments based on lenticular substrate platelets.

[0160] Vacuum metallized pigments (VMPs) can be obtained, for example, by releasing metals, metal alloys, or metal oxides from appropriately coated foils. They are characterized by a particularly thin substrate platelet thickness in the range of 5 to 50 nm and a particularly smooth surface with increased reflectivity. Substrate platelets comprising a vacuum-metallized pigment are also referred to as VMP substrate platelets in this application. VMP substrate platelets made of aluminum can be obtained, for example, by releasing aluminum from metallized foils.

[0161] The substrate plates made of metal or metal alloy can be passivated, for example by anodizing (oxide layer) or chromating.

[0162] Uncoated lamellar, lenticular, and / or VPM substrate plates, especially those made of metal or metal alloy, reflect incident light to a high degree and create a light-dark flop. These have proven particularly preferred for use in the aftertreatment agent.

[0163] Suitable pigments based on a lamellar substrate platelet include, for example, the pigments of the VISIONAIRE series from Eckart.

[0164] Pigments based on a lenticular substrate platelet are available, for example, under the name Alegrace® Gorgeous from Schlenk Metallic Pigments GmbH.

[0165] 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.

[0166] The pigment(s) are preferably used in specific quantity ranges on average. Particularly good results were obtained when the aftertreatment 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.%, based on the total weight of the aftertreatment agent.

[0167] In a further very particularly preferred embodiment, a process according to the invention is characterized in that the aftertreatment agent (N) - based on the total weight of the aftertreatment 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 from 0.2 to 2.5 wt.% and very particularly preferably from 0.25 to 1.5 wt.%.

[0168] Steps in the process

[0169] The process for dyeing keratin fibers, especially human hair, comprises

[0170] - applying a dye (F) to the keratin fibers, which contains at least one direct dye (F-1), and

[0171] - Application of a post-treatment agent (N) to the keratin fibers, which contains at least one chitosan and / or a chitosan derivative (N-1).

[0172] The process for improving the washfastness of dyed keratin fibers, which were dyed by applying a dyeing agent (F) containing at least one direct dye (F-1), comprises applying a post-treatment agent (N) to the dyed keratin fibers, which contains at least one chitosan and / or a chitosan derivative (N-1). In both processes, which are essentially identical, the dyeing agent (F) is first applied to the keratin fibers, followed by the application of the post-treatment agent (N).

[0173] In a further explicitly particularly preferred embodiment, the method according to the invention for dyeing the keratin fibers or for improving the washfastness of the dyed keratin fibers is characterized in that the dyeing agent (F) is applied before the after-treatment agent (N).

[0174] The washout of the direct dye(s) (F-1) can be reduced or prevented by applying the after-treatment agent (N). To utilize this effect as early as possible, the after-treatment agent (N) is therefore preferably applied either directly after application—and preferably after washout—of the colorant (F) or before, during, or after the first hair wash. Depending on the user's habits, the hair is usually washed every one to four days. The period between the application of the colorant (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 colored keratin fibers were washed for the first time.

[0175] In a further particularly preferred embodiment, a process according to the invention is therefore characterized in 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 not more than 96 hours, preferably not more than 72 hours, more preferably not more than 48 hours, even more preferably not more than 12 hours and most preferably not more than 3 hours.

[0176] Since the after-treatment agent (N), as described above, is particularly preferably formulated as a water-rich and / or low-viscosity formulation, it can be particularly well sprayed onto the keratin fibers in the form of a spray.

[0177] In an explicitly particularly preferred embodiment, a method according to the invention is therefore characterized in that the after-treatment agent (N) is sprayed onto the keratin fibers.

[0178] For example, the post-treatment agent (N) can be provided 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 have long been particularly popular due to their ease of use. However, due to the environmental concerns of fluorocarbon propellants and the flammability of hydrocarbons and dimethyl ether, propellant-free dispenser containers with spray valves have also become increasingly popular.

[0179] 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-lever pumps. Propellant-free spray systems also include elastomer pressure spray systems, in which an elastomer bag in 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 bag. The most important systems to date have been pump spray bottles with finger or hand pumps. These dispenser containers with a spray valve can be purchased commercially from various suppliers, for example in the form of transparent glass bottles (75 ml, 100 ml, or 250 ml) with a pump spray attachment.

[0180] After application, the aftertreatment agent (N) can be left on for a period of, for example, 1 to 60 minutes, preferably 5 to 45 minutes. In principle, the aftertreatment agent (N) can be rinsed out after application. However, a particularly significant improvement in washfastness was achieved when the aftertreatment agent (N) was designed as a leave-on product, in which the keratin fibers still covered with the aftertreatment agent (N) were dried. Since the aftertreatment agent (N) preferably has a high to very high water content, it is advantageous to shorten the drying time through heat treatment.

[0181] In a further explicitly particularly preferred embodiment, a method according to the invention is therefore characterized by heating the keratin fibers covered with the aftertreatment agent (N) to a temperature of more than 40 °C.

[0182] 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, the process in this embodiment is a leave-on dyeing process.

[0183] Heating or heat treatment involves 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 devices used include a hairdryer, a blow dryer, a thermal cap, a flat iron, a curling iron, or an infrared lamp.

[0184] 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 hair dryer, a blow dryer, a heat cap, a straightening iron, a curling iron or an infrared lamp.

[0185] Furthermore, it has been found that it is preferred if the treatment temperature during the heat treatment is between 40 °C and 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. In other words, it has proven particularly preferred if the heat treatment is carried out using a device that is heated 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.

[0186] In a further particularly preferred embodiment, a method according to the invention is characterized by heating the keratin fibers covered with the aftertreatment 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.

[0187] The duration of the heat treatment can be adapted to the selected temperature range. For example, a 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.

[0188] In the course of the method according to the invention, the keratin fibers can be subjected to a heat treatment entirely, but the treatment of partial areas of the keratin fibers can also be included. Complete heat treatment of the keratin fibers is preferred, ie, preferably all keratin fibers to which the post-treatment agent (N) has been applied are treated with heat.

[0189] During heat treatment or heating, the keratin fibers can also be combed or brushed.

[0190] For example, the keratin fibers or the hair can be treated with a hairdryer that blows warm or hot air onto the fibers, possibly while combing or brushing. This air is particularly preferably between 50 and 80°C. Alternatively, the keratin material or the hair can be held under an infrared lamp, which is particularly preferably set to a temperature of 50 to 80°C. For the purpose of heat treatment, hair can also be pressed between two appropriately temperature-controlled plates of a straightening iron, with the plates simultaneously moving along the fiber. The straightening iron plates can, for example, be set to a temperature of up to 210°C.

[0191] 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 hair dryer, a blow dryer, a heat cap, a straightening iron, a curling iron or an infrared lamp.

[0192] Furthermore, a method comprising the following steps is particularly preferred

[0193] (1) Applying the coloring agent (F) as previously described to the keratin fibers,

[0194] (2) exposure to the dye applied in step (1),

[0195] (3) Rinsing out the dye,

[0196] (4) Applying the after-treatment agent (N) as previously described to the keratin fibers, preferably in the form of a spray,

[0197] (5) exposure to the after-treatment agent (N) used in step (4), and

[0198] (6) Heating the keratin fibres covered with the after-treatment agent (N) to a temperature of more than 40 °C.

[0199] In the particularly preferred leave-on process, the aftertreatment agent (N) is applied to the keratin fibers or sprayed onto the fibers (step (4)), followed by the exposure (step (5)). During the exposure, the aftertreatment agent (N) is evenly distributed over the keratin fibers. Since the aftertreatment agent (N) is no longer rinsed out of the keratin fibers in this embodiment, the exposure time cannot be precisely defined, but in principle lasts at most until the dried aftertreatment agent is removed from the keratin fibers again (e.g. by shampooing or mechanical abrasion). The exposure (step (5)) and the heating or drying of the keratin fibers (step (6)) can therefore also overlap in time.According to the invention, the action of the liquid aftertreatment agent can last at least until the aftertreatment agent has completely dried on the keratin fibers in step (6), which, depending on the temperature, can take, for example, 5 to 60 minutes. Repeated application of the aftertreatment agent (N).

[0200] Very good improvements in washfastness were also observed when the aftertreatment agent (N) was repeatedly applied to the colored keratin fibers. Repeated application is conceivable, for example, before, during, or particularly preferably after each hair wash. The user can wash their hair as usual with shampoo, rinse out the shampoo, then apply or spray the aftertreatment agent (N) to the still damp, slightly dried, or dry hair, and then dry the hair treated with the aftertreatment agent. Application of the aftertreatment agent (N) after every second, third, fourth, fifth, or sixth hair wash is also according to the invention.

[0201] Improvement of wash fastness

[0202] The after-treatment agents (N) described above are used to improve the washfastness of keratin fibers or hair that has been dyed with a dye containing at least one direct dye.

[0203] For the purposes of the present invention, an improvement in wash fastness means that keratin fibers which have previously been dyed with the coloring agent (F) have a higher color intensity when using the after-treatment agent (N) after a defined number of hair washes than without using the after-treatment agent (N).

[0204] The improvement in washfastness can be quantified, for example, through colorimetric measurements (measurement of L, a, and b values) and calculation of the color difference. The smaller the color difference between washed and unwashed hair, the better the washfastness or color retention.

[0205] 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 or second subject matter of the invention, for improving the washfastness of keratinic fibers which have been dyed with a dyeing agent containing at least one direct dye.

[0206] With regard to the further preferred embodiments of the use according to the invention, what has been said regarding the methods according to the invention applies mutatis mutantis.

[0207] Examples

[0208] 1 . Formulations

[0209] The following dyes were prepared (all data in wt.% unless otherwise stated):

[0210] The following aftertreatment agent was prepared:

[0211] 2. Application

[0212] The dyes (F1) and (F2) were each applied to strands of hair (Kerling Euronaturhaarweiß, length approx. 5 cm). For this, the strands were moistened, then the dye was applied (0.4 g of dye per 1 g of strand) and left to work for 15 minutes at 30°C. The strands were then rinsed under running water for 1 minute.

[0213] 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.

[0214] After a 5-minute exposure time, the strands still treated with the after-treatment agent (N) were dried at 50 °C. The strands were then colorimetrically measured.

[0215] 3. Measurement of wash fastness after a single post-treatment

[0216] Following coloring and aftercare, each colored strand underwent 6 or 12 manual hair washes. For each wash, the strand was moistened, then a commercially available shampoo (Schwarzkopf, Schauma 7 Kräuter) was massaged into the strand for 25 seconds (0.25 g of shampoo per gram of hair). Following this, the strand was rinsed with lukewarm tap water for 30 seconds and dried. The strands were colorimetrically measured again after 6 and 12 strands, respectively.

[0217] For comparison, hair strands were treated with the dye (F1) or (F2) as previously described, but were not subjected to any post-treatment and then washed 6 or 12 times.

[0218] The dE value used to assess the color difference is calculated from the L*a*b* color values ​​measured on the respective strand as follows: dE = [ (Li - Lo) 2 + (ai - ao) 2 + (bi - bo) 2 ] 1 / 2

[0219] Lo, ao and bo = measurements of the dyed strand

[0220] Li, ai and bi = measurements of the dyed and washed strand

[0221] The larger the dE value, the greater the color difference between the colored hair and the colored and washed hair and the greater the color change (i.e., the worse the washfastness).

[0222] HW = hair washing

[0223]

[0224] Hair strands dyed in the shade autumn orange using the process according to the invention showed significantly improved washfastness after 6 washes (E2 versus V2). Even after 12 washes, washfastness was still slightly improved compared to dyeing without aftertreatment (E3 versus V3).

[0225]

[0226] Hair strands dyed in the shade sea blue using the process according to the invention showed significantly improved washfastness after 6 washes (E5 versus V5). Even after 12 washes, washfastness was still significantly improved compared to the dyeing process without post-treatment (E6 versus V6).

[0227] A particularly strong improvement in washfastness was achieved after post-treatment when the hair strands had previously been dyed with cationic dyes. 4. Measurement of washfastness after repeated post-treatment

[0228] A further series of experiments was conducted in which the hair strands were repeatedly treated with the after-treatment agent (N). Following the coloring and after-treatment described under point 2, each colored strand was subjected to 6 or 12 manual hair washes, with every sixth wash followed by a treatment with the after-treatment agent (N).

[0229] For each wash, the strand was moistened, then a commercially available shampoo (Schwarzkopf, Schauma 7 Kräuter) 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. After every 6 washes, the after-treatment product was sprayed from a pump-type spray bottle onto the still-towel-damp strands of hair (0.4 g of after-treatment product per 1 g of hair strand) and massaged in. After a contact time of 5 minutes, the strands still treated with the after-treatment product (N) were dried at 50°C.

[0230] The shampooing was repeated for the next wash. After 6 or 12 strands of hair, the strands were colorimetrically measured again.

[0231] For comparison, hair strands were treated with the dye (F1) or (F2) as previously described, but were not subjected to any post-treatment and then washed 6 or 12 times.

[0232]

[0233] Hair strands dyed in the shade autumn orange using the process according to the invention showed significantly improved washfastness (E8 versus V2) after 6 washes (plus one after-treatment immediately after coloring and one after 6 washes). Even after 12 washes (plus one after-treatment immediately after coloring and two after-treatments after 6 and 12 washes), washfastness was still significantly improved (E9 versus V3).

[0234]

[0235] Hair strands dyed in the shade sea blue using the process according to the invention showed significantly improved washfastness (E11 versus V5) after 6 washes (plus one after-treatment immediately after coloring and one after 6 washes). Even after 12 washes (plus one after-treatment immediately after coloring and two after-treatments after 6 and 12 washes), washfastness was still significantly improved compared to the dyeing process without after-treatment (E12 versus V6).

[0236] Compared to a single after-treatment, the washfastness of the colorations was further improved by repeated applications of the after-treatment product. This effect was particularly evident after 12 washes and was particularly pronounced when dyeing with cationic direct dyes.

Claims

Patent claims 1. A process for dyeing keratin fibers, in particular human hair, comprising the following steps: - applying a dye (F) to the keratin fibers, which contains at least one direct dye (F-1), and - Application of a post-treatment agent (N) to the keratin fibers, which contains at least one chitosan and / or a chitosan derivative (N-1).

2. A process for improving the washfastness of dyed keratin fibers which have been dyed by applying a colorant (F) containing at least one direct dye (F-1), wherein a post-treatment agent (N) containing at least one chitosan and / or a chitosan derivative (N-1) is applied to the dyed keratin fibers.

3. Process according to claim 1 or claim 2, characterized in that the colorant (F) contains at least one direct dye (F-1) from the group of cationic, non-ionic and / or anionic direct dyes, preferably from the group of cationic and / or non-ionic direct dyes, very particularly preferably from the group of cationic direct dyes.

4. The method according to any one of claims 1 to 3, characterized in that the aftertreatment agent (N) contains at least one chitosan and / or a 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.

5. Process according to one of claims 1 to 4, characterized in that the aftertreatment agent (N) - based on the total weight of the aftertreatment agent (N) - contains one or more chitosans and / or chitosan derivatives in a total amount of 0.1 to 10.0 wt.%, preferably of 0.2 to 8.0 wt.%, more preferably of 0.5 to 6.0 wt.% and most preferably of 0.7 to 2.0 wt.%.

6. Process according to one of claims 1 to 5, characterized in that 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.

7. The method according to any one of claims 1 to 6, characterized in 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).

8. The method according to any one of claims 1 to 7, characterized in 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 wt.%, more preferably at least 96 wt.% and most preferably at least 99 wt.%.

9. Process according to one of claims 1 to 8, characterized in that 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 very particularly preferably of 100 to 2,000 mPas (22 °C / Brookfield viscometer / spindle 3 / 30 rpm).

10. The method according to any one of claims 1 to 9, characterized in that the aftertreatment agent (N) contains at least one pigment, preferably at least one pigment from the group of inorganic and / or organic pigments.

11. Method according to one of claims 1 to 10, characterized in 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 48 hours, preferably maximum 24 hours, more preferably maximum 12 hours, even more preferably maximum 6 hours and most preferably maximum 3 hours.

12. Method according to one of claims 1 to 11, characterized in that the after-treatment agent (N) is sprayed onto the keratin fibers.

13. Method according to one of claims 1 to 12, comprising heating the keratin fibers covered with the after-treatment agent (N) to a temperature of more than 40°C.

14. Method according to one of claims 1 to 13, comprising the following steps (1) Applying the colorant (F) to the keratin fibers, (2) exposure to the dye applied in step (1), (3) Rinsing out the dye, (4) Applying the after-treatment agent (N) to the keratin fibres, preferably in the form of a spray, (5) exposure to the after-treatment agent (N) used in step (4), and (6) Heating the keratin fibres 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 direct dye.

Images