WO2001080815A1

WO2001080815A1 - Hair coloring method

Info

Publication number: WO2001080815A1
Application number: PCT/EP2001/004156
Authority: WO
Inventors: Thomas Otto Gassenmeier; Josefine Schröder; Peter Busch
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 2000-04-19
Filing date: 2001-04-11
Publication date: 2001-11-01
Also published as: DE10019404A1; AU2001262192A1

Abstract

The invention relates to a method for coloring hair according to which the hair is firstly pretreated with an aqueous preparation (A), which contains a protein, protein hydrolysate or protein derivative that is dissolved therein. The hair is then brought into contact with a coloring preparation (B) and, after an exposure time, is washed using water or an aqueous shampoo. A hair color set is suited for carrying out the inventive method and consists of two separately packaged components (A) and (B) which are placed together to form a unit for sale. Component (A) is an aqueous preparation having preferably 1-20 wt. % of a protein, protein hydrolysate or protein derivative that is dissolved therein, and component (B) is a coloring preparation having at least one hair colorant or colorant intermediate product.

Description

.Haarfärbeverfahren "

The invention relates to a two-stage process for dyeing keratin fibers, in which the hair is pretreated with a preparation which contains a dissolved protein or protein derivative before the actual dyeing.

Processes for tinting and coloring the hair serve to specifically change the natural hair color according to the wishes of the customer. Such methods are used either for general aesthetic reasons or to achieve a younger appearance by covering gray hair with hair dyes.

Usual hair dyes can either be produced with direct hair dyes, but particularly durable, lightfast and washable dyeings are mainly achieved using oxidation dyes.

To produce oxidation colorations, preparations of oxidation dye precursors are either applied directly to the hair and develop the dye there under the oxidative influence of atmospheric oxygen, or they are mixed with an oxidizing agent immediately before use on the hair and then applied to the hair. Instead of an oxidizing agent, a catalyst can also be added which catalyzes the air oxidation, e.g. B. a transition metal salt or an enzyme.

The color intensities achieved during hair dyeing and the resistance of the dye to light and hair washing are unfortunately often unsatisfactory. This can be due to the fact that dyes which are particularly favorable in terms of toxicology but only moderate in terms of application technology are used, or that, for reasons of protecting the hair, one works at neutral or only weakly alkaline pH values which are not optimal for the color absorption. Too low a color intensity is also achieved when the dye concentrations are too low or when the hair to be colored is completely undamaged, since it has not been subjected to any coloring or chemical deformation. Attempts have therefore always been made to improve the intensity and authenticity of hair coloring by means of a wide variety of measures which can be taken without increasing the damage to the hair. From WO 93/19722 AI z. B. a method for improving the intensity and wash fastness of hair dyeing is known, in which one treats the colored hair with an aqueous solution of a protein or protein hydrolyzate and a metal salt which forms an insoluble precipitate with the protein.

From EP 0 357 351 B1 hair conditioning agents containing quaternary ammonium polymers are known which are used as pretreatment agents before chemical hair treatment such as. B. a hair color, can be used to reduce hair damage from this treatment.

From JP 01/275 519 AI it was known to add quaternary ammonium derivatives of protein hydrolyzates to hair colorants in order to reduce hair damage by dyeing and to achieve good fastness properties.

It has now been found that pretreatment of the hair with a preparation which contains a dissolved protein, protein hydrolyzate or protein derivative increases the intensity and authenticity of a subsequent dyeing of the hair and furthermore significantly improves the sensory, cosmetic properties of the dyed hair can.

The invention therefore relates to a process for dyeing hair, characterized in that the hair

- pretreated with an aqueous preparation (A) which contains a protein, protein hydrolyzate or protein derivative dissolved therein,

- in contact with a dye preparation (B) and after an exposure time

- Washes with water or an aqueous shampoo.

Suitable water-soluble proteins come e.g. B. egg albumin or casein in question. As water-soluble protein hydrolyzates come e.g. B. of collagen (gelatin), keratin, elastin or vegetable proteins such. B. soy protein, wheat gluten, legume protein, almond protein and algae protein in the form of their alkali or alkaline earth salts. Protein hydrolyzates are preferably not to be understood as so-called full hydrolyzates, but rather those which still have considerable proportions of oligo- and polypeptide molecules.

Other protein derivatives which are suitable for the purposes of the invention would be e.g. B. those obtained by reductive or oxidative protein degradation, e.g. B. keratosis or keratein. Water-soluble condensation products from protein hydrolyzates and fatty acids, from protein hydrosates and rosin or adducts of ethylene oxide or propylene oxide with protein fractions or protein degradation products are also suitable.

Cationic protein derivatives are particularly suitable. These include those protein derivatives which can be obtained by condensation with cationic alkylating agents. Such alkylating agents are e.g. B. the glycidyl-trialkylammoniumchloride or the 3-CMor-2-hydroxypropyl-trialkylammoniumchloride. These compounds preferably contain three methyl groups or a long-chain alkyl or acylarnidopropyl group and two methyl groups in the quaternary ammonium group. By condensation with the proteins or protein hydrolyzates, products are then obtained, the names of which, for. B. N, N-Dimethyl-N-cocoalkyl-hydroypropyl collagen hydrolyzate (INCI: Cocodimonium Hydroxypropyl Hydrolyzed Collagen) or N, N-Dimethyl ~ N-stearyl-hydroxypropyl Wheat Protein Hydrolyzate (INCI: Steardimonium Hydrosypropyl Hydrolyzed Wheat Protein).

The aqueous preparation (A) preferably contains 1 to 20% by weight of a dissolved protein, protein hydrolyzate or protein derivative, in particular 1 to 5% by weight. The water solubility of the protein, protein hydrolyzate or protein derivative should therefore be at least so high that at least 1% by weight of the protein, protein hydrolyzate or protein derivative dissolves in the aqueous preparation (A). In a preferred embodiment of the method according to the invention, the aqueous preparation (A) contains a protein hydrolyzate or a quaternized protein hydrolyzate and has a pH of 4 to 6.5. The aqueous preparation (A) for pretreating the hair can be in the form of a lotion, a gel or an oil-in-water emulsion and therefore in addition to the protein derivative contain further components which are known and customary for the formulation of such preparations.

The preparation can be spread on the hair by hand or applied to the hair as an aerosol spray or aerosol using a pump spray or propellant. In particular, preparation (A) can contain surface-active substances (surfactants). Care must be taken to ensure that there are no incompatibilities or the formation of precipitates between the surfactant and protein derivatives. When using cationic protein derivatives, the use of nonionic, ampholytic, zwitterionic or cationic surfactants is therefore preferred.

Water-soluble polymers can, for. B. as a thickener, the preparation (A) with the dissolved protein, protein hydrolyzate or protein derivative. Here too, the compatibility of the product used with the protein or protein derivative must be taken into account. So z. B. aniomic polymers with cationic protein derivatives or cationic polymers with anionic protein derivatives form precipitates.

Finally, oil or fat components in finely dispersed or emulsified form can also be present in the aqueous preparation (A). As oil or fat components such. B. hydrocarbons, silicones, esters, fats and oils (triglycerides) liquid and solid waxes, fatty alcohols, di-n-alkyl ethers with 12-40 C atoms, (free) fatty acids, fatty acid amides or fatty acid alkanolamides, fatty acid partial glycerides, sorbitan fatty acid partial esters and others serve water-insoluble oil and fat components.

In addition to the constituents mentioned, the aqueous preparation (A) can also contain other hair cosmetically interesting components, in particular those which promote the application of color or the authenticity of the color or the oxidative development of oxidation dyes during the subsequent dyeing process. Such substances can e.g. These can be, for example, catalysts which promote the oxidation of the dye precursors to the dye on the hair or which activate the atmospheric oxygen to form peroxides for the oxidation of the dye precursors. Suitable catalysts are e.g. B. transition metal salts, iodides and enzymes such. B. oxidoreductases, catalases and peroxidases. The dye preparation (B) contains dyes or dye precursors which either dye the hair directly or which develop a dye suitable for hair dyeing in the presence of atmospheric oxygen or suitable oxidizing agents.

Certain natural dyes such as e.g. B. henna and extracts or ground plant parts of strongly coloring plants such. B. indigo, madder, chamomile, walnut shells, black tea and also synthetic dyes, e.g. B. pyrogallol, nitroaromatics, azo dyes, triphenylmethane dyes, anthraquinone dyes or indophenols. Preferred direct dyes are those with the international names or trade names HC Yellow 2, HC Yellow 4, HC Yellow 5, HC Yelow 6, HC Yellow 12, Basic Yellow 57, Acid Yellow 1 (CI 10316), Disperse Orange 3, HC Red 3, HC Red BN, Basic Red 2, Basic Red 76, Acid Red 87 (CI 45380), HC Blue 2, HC Blue 12, Disperse Blue 3, Basic Blue 7, Basic Blue 99, FD&C Green 3 (CI 42053 ), D&C Green No. 8 (CI 59040), HC Violet 1, Basic Violet 14, Disperse Violet 1, Disperse Violet 4, Disperse Black 9, Acid Black 52, Basic Brown 16 and Basic Brown 17 known compounds as well as 1,4-bis- (ß-hydroxyethyl ) -amino-2-nitrobenzene, 4-amino-2-nitrodiphenylamine-2 '-carboxylic acid, 6-nitro-l, 2,3,4-tetrahydroquinoxaline, hydroxyethyl-2-nitro-toluidine, picramic acid, sodium picramate, 2-amino -6-chloro-4-nitrophenol, 4-ethylamino-3-nitrobenzoic acid and 2-chloro-6-ethylamino-1-hydroxy-4-nitrobenzene. Particularly preferred direct dyes are the nitroaromatics, the basic direct dyes and triphenylmethane derivatives. 3-Nitro-4-aminophenol, 4- (3'-hydroxypropylamino) -3-nitrophenol (HC Red BN), 1,4-bis (β-hydroxyethyl) amino-2- nitrobenzene, l- (ß-hydroxyethylamino) -2-nitro-4-aminobenzene (HC RedNo. 3), l- (ß-hydroxyethylamino) - 2-nitrobenzene (HC Yellow No. 2), 4- (ß-hydroxyethylamino) -3-nitrophenol, HC Blue 2, Basic Blue 99, Basic Red 76, Basic Brown 16 and Basic Brown 17.

The dyeing preparation (B) preferably contains the substantive dyes in an amount of 0.001-20% by weight and very particularly preferably in an amount of 0.01 to 5% by weight, based on the entire dyeing preparation (B) in an aqueous carrier. However, the dye preparation (B) preferably contains oxidation dye precursors and, if appropriate, oxidizing agents or an oxidation catalyst. The oxidation dye precursors include at least those of the developer type, that is to say products which, under the influence of air or chemical oxidizing agents, form reactive, polymerizable intermediates which polymerize to give dyes. However, dye precursors of the coupler type are also preferably present, which do not themselves polymerize to dyes, but which also react with the dye development of the developer compounds and modify the dyes formed. Primary aromatic amines with a further free or substituted hydroxy or amino group in the para or ortho position, diaminopyridine derivatives, heterocyclic hydrazones, 4-aminopyrazole derivatives and 2,4,5,6-tetraaminopyrimidine are usually used as oxidation dye precursors of the developer type and its derivatives used. Suitable developer components are, for example, p-phenylenediamine, p-toluenediamine, p-aminophenol, o-aminophenol, 1- (2'-hydroxyethyl) -2,5-diaminobenzene, N, N-bis (2-hydroxyethyl) -p-phenylenediamine, 2- (2,5-diaminophenoxy) ethanol, 4-amino-3-methylphenol, 2,4,5, 6-tetraaminopyrimidine, 2-hydroxy-4,5,6-triaminopyrimidine, 4-hydroxy -2,5,6-triaminopyrimidine, 2,4-dihydroxy-5,6-diaminopyrimidine, 2-dimethylamino-4,5,6-triaminopyrimidine, 2-hydroxymethylamino-4-amino-phenol, bis- (4-aminophenyl) amine, 4-amino-3-fluorophenol, 2-aminomethyl-4-aminophenol, 2-hydroxymethyl-4-aminophenol, 4-amino-2 - ((diethylamino) methyl) phenol, bis (2-hydroxy-5 -aminophenyl) -methane, 1,4-bis- (4-aminophenyl) -diazacycloheptan, 1,3-bis (N (2-hydroxyethyl) -N (4-aminophenylamino)) -2-propanol, 4- amino- 2- (2-hydroxyethoxy) phenol, 1, 10-bis (2,5-diaminophenyl) -1, 4.7, 10-tetraoxadecane and 4,5-diaminopyrazole derivatives according to EP 0 740 741 or WO 94 / 08970 such as B. 4,5-diamino-l- (2'-hydroxyethyl) pyrazole. Particularly advantageous developer components are p-phenylenediamine, p-toluenediamine, p-aminophenol, 1- (2'-hydroxyethyl) -2,5-diaminobenzene, 4-amino-3-methylphenol, 2-aminomethyl-4-aminophenol, 2,4 , 5, 6-tetraaminopyrimidine, 2-hydroxy-4,5,6-triaminopyrimidine, 4-hydroxy-2,5,6-triaminopyrimidine.

The developer components p-phenylenediamine, p-toluenediamine, p-aminophenol, 1- (2'-hydroxyethyl) -2,5-diaminobenzene, 4-amino-3-methylphenol, 2-aminomethyl-4- aminophenol and 2,4,5,6-tetraaminopyrimidine have proven to be particularly preferred, in particular to achieve the fashion nuances.

M-Phenylenediamine derivatives, naphthols, resorcinol and resorcinol derivatives, pyrazolones and m-aminophenol derivatives are generally used as oxidation dye precursors of the coupler type. Examples of such coupler components are m-aminophenol and its derivatives such as 5-amino-2-methylphenol, 5- (3- hy droxypropylamino) -2-methyphenol, 3 - amino-2-chloro-6-methyphenol, 2- Hydroxy-4-aminophenoxyethanol, 2,6-dimethyl-3-aminophenol, 3-trifluoroacetylamino-2-chloro-6-methylphenol, 5-amino-4-chloro-2-methylphenol, 5-amino-4-methoxy-2 -methylphenol, 5- (2 ^ς -hydroxyethyl) -amino-2-methylphenol, 3- (diethylamino) phenol, N-cyclopentyl-3-aminophenol, 1, 3-dihydroxy-5- (methylamino) -benzene, 3- (Ethylamino) -4-methylphenol and 2,4-dichloro-3-aminophenol, o-aminophenol and its derivatives, m-diaminobenzene and its derivatives such as, for example, 2,4-diaminophenoxyethanol, 1,3-bis- (2, 4-diaminophenoxy) propane, l-methoxy-2-amino-4- (2'-hydroxyethylamino) benzene, 1,3-bis (2,4-diaminophenyl) propane, 2,6-bis- ( 2-hydroxyethylamino) -l-methylbenzene and l-amino-3-bis (2'-hydroxyethyl) aminobenzene, o-diaminobenzene and its derivatives such as 3,4-diaminobenzoic acid and 2,3-diamino-l-methylbenzene,

- Di- or trihydroxybenzene derivatives such as resorcinol, resorcinol monomethyl ether, 2-methylresorcinol, 5-methylresorcinol, 2,5-dimethylresorein, 2-chlororresorcinol, 4-chlororesorcinol, pyrogallol and 1,2,4-trihydroxybenzene, pyridine derivatives such as 2, 6-dihydroxypyridine, 2-amino-3-hydroxypyridine, 2-amino-5-chloro-3-hydroxypyridine, 3-amino-2-methylamino-6-methoxypyridine, 2,6-dihydroxy-3, 4-dimethylpyridine, 2, 6-dihydroxy-4-methylpyridine, 2,6-diaminopyridine, 2,3-diamino-6-methoxypyridine and 3,5-diamino-2,6-dimethoxypyridine,

Naphthalene derivatives such as 1-naphthol, 2-methyl-1-naphthol, 2-hydroxymethyl-1-naphthol, 2-hydroxyethyl-1-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxy naphthalene, 1, 7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,7-dihydroxynaphthalene and 2,3-dihydroxynaphthalene, Morpholine derivatives such as 6-hydroxybenzomorpholine and 6-aminobenzomo holin,

Quinoxaline derivatives such as 6-methyl-1, 2,3,4-tetrahydroquinoxaline, pyrazole derivatives such as l-phenyl-3-methylpyrazol-5-one, indole derivatives such as 4-hydroxyindole, 6-hydroxyindole and 7-hydroxyindole,

Methylenedioxybenzene derivatives such as l-hydroxy-3,4-methylenedioxybenzene, l-amino-3,4-methylenedioxybenzene and l- (2'-hydroxyethyl) amino-3,4-methylenedioxybenzene.

Particularly suitable coupler components are 1-naphthol, 1,5-, 2,7- and 1,7-dihydroxynaphthalene, 3-aminophenol, 5-amino-2-methylphenol, 2-amino-3-hydroxypyridine, resorcinol, 4-chlororesorcinol, 2-chloro-6-methy 1-3 -aminophenol, 2-methylresorcinol, 5-methylresorcinol, 2,5-dimethylresorcinol, 2,6-di- (ß-hydroxyethylamino) -toluene and 2,6-dihydroxy-3 , 4-dimethylpyridine.

Very particularly preferred coupler components, in particular to achieve the modern shades in the red area, are 2-chloro-6-methyl-3-aminophenol, 5-amino-2-methylphenol, 2-amino-3-hydroxypyridine, 2,6-di- (ß -hydroxyethylamino) toluene, 2-methylresorcinol and 1-naphthol.

The developer / coupler combination 2,4,5,6-tetraaminopyrimidine and 2-methylresorcinol is particularly preferred for achieving reddish shades. Very interesting dye precursors for the dye preparation (B) according to the invention are also the indole and indoline derivatives, in particular 5,6-dihydroxyindoline, which is a precursor of nature-analogous melanin dyes, but also the role of a coupler in mixtures with other oxidation dye precursors (color modifier) can take over. Other compounds suitable as precursors of natural analog dyes are e.g. B. the N-methyl-5,6-dihydroxyindoline, the N-ethyl-5,6-dihydrosyindoline, the 5,6-dihydroxyindoline-2-carboxylic acid, the 6-hydroxyindoline, the 6-aminoindoline and the 4-aminoindoline. The corresponding indole derivatives can also be used as dye precursors. All of the oxidation dye precursors mentioned which contain aromatic amino groups can be used in the process according to the invention both as free bases and in the form of their physiologically tolerable salts with inorganic or organic acids, for. B. be used as hydrochlorides, hydrobromides or sulfates. The oxidation dye precursors are contained in the dye preparation (B) in amounts of 0.05-10% by weight, preferably 0.2-5% by weight.

The dye preparation (B), in particular if oxidation dye precursors are present, becomes slightly acidic to alkaline, i.e. H. adjusted to pH values in the range from about 5 to 11. For this purpose, the coloring preparation contains alkalizing agents, usually alkali or alkaline earth metal hydroxides, ammonia or organic amines. Preferred alkalizing agents are monoefhanolamine, monoisopropanolamine, 2-amino-2-methyl-propanol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, 2-amino-2 -methylbutanol and triethanolamine as well as alkali and alkaline earth metal hydroxides. Monoethanolamine, triethanolamine and 2-amino-2-methyl-propanol and 2-amino-2-methyl-1,3-propanediol are particularly preferred in this group. It is also possible to use ω-amino acids such as ω-aminocaproic acid as an alkalizing agent.

If the development of the color is not already under the influence of atmospheric oxygen, this can be done using conventional oxidizing agents such as e.g. B. hydrogen peroxide or its adducts with urea, melamine or sodium borate can be used. In this case, the oxidizing agent must be added to the hair immediately before the dye preparation is used in order to prevent it from developing prematurely into a high-molecular dye which is then no longer solid. The oxidizing agent may also only be applied to the hair after the coloring agent has been prepared. However, it is preferred that the coloring preparation (B) which is brought into contact with the hair according to the invention contains oxidation dye precursors and, if appropriate, an oxidizing agent or an oxidation catalyst. The transition metal compounds, iodides or enzymes already mentioned are suitable as oxidation catalysts. These catalysts are also used if they are not mixed with the aqueous protein are applied to the hair (A), added to the dye preparation (B) only immediately before use on the hair.

The dyeing preparation (B) is brought into contact with the hair for a period of time which is sufficient for the hair fiber to be colored. This exposure time can range from a few seconds to 20 minutes, depending on the degree of absorption of the dyes on the hair. An exposure time of 1 to 5 minutes at a temperature of 20 to 35 ° C is usually sufficient.

After dyeing, the hair is washed with water or an aqueous shampoo to rinse off excess dye preparation from the hair.

The hair dyeing method according to the invention is suitable both for home use and for professional use by the hairdresser. For home use, however, it is advisable to offer the user the preparations required for the proper implementation of the procedure with detailed instructions in a sales unit for single or repeated use as a "hair dye set". This enables pretreatment preparation (A) and dye preparation ( B) optimally match each other in quantity and concentration so that the user cannot fail.

Another object of the invention is therefore a hair dye set consisting of at least two separately packaged components (A) and (B) combined to form a sales unit, characterized in that component (A) is an aqueous preparation with a protein dissolved therein, Protein hydrolyzate or protein derivative and component (B) is a dye preparation with at least one hair dye or dye precursor. If the dye preparation is to contain oxidation dyes which require an oxidizing agent in order to develop the color, it is necessary that component (B) comprises an aqueous dye preparation (B1) containing oxidation dye precursors and a further component (B2) which comprises a Contains oxidizing agents. These components are also packaged separately in the hair coloring set according to the invention and are used by the user immediately before use on the hair for ready-to-use dye preparation (B). The oxidizing agent preparation (B2) can, for. B. an aqueous solution of hydrogen peroxide, optionally with additions of surfactants, emulsified oil components, water-soluble thickeners, complexing agents and buffer salts, adjusted to a weakly acidic pH. The oxidizing agent preparation (B2) can also, for. B. a powdered preparation of an HO ₂ adduct, for. B. of urea perhydrate or melamine perhydrate with powdered carriers, thickeners or buffer salts.

The hair dye set according to the invention may also contain other separately packaged components, e.g. B. a care shampoo or conditioner that is used after the exposure time of the colorant to rinse out excess dye preparation from the hair.

The following examples are intended to explain the subject matter of the invention in more detail:

Examples:

1. Pretreatment with gelatin

Approximately Strands of hair 12 cm long (from Alkinco, New York) were pretreated with a solution of 5% by weight gelatin (type A, pH = 5.5-6.0) in water at 25 ° C. for 10 minutes. The tresses were then rinsed with water for 2 minutes and colored with commercially available oxidation colorants. After 30 minutes of exposure, the coloring batch was rinsed out of the hair. The locks of hair were then washed 10 times with a shampoo (10% by weight Na lauryl ether sulfate), rinsed and dried.

In parallel, untreated hair strands of the same hair sample were dyed, shampooed and rinsed in the same way.

Hair dye Color intensity without pretreatment with pretreatment

Poly Color Brilliance Dark Brown 3,375 4,250

Poly Color Brilliance Autumn Brown 3,625 4,500

Poly Color Brilliance mahogany 3.75 4,500

Poly Color Brilliance Sweet Chestnut 3,500 4,060

Poly Color Brilliance Bordeaux Red 4,000 4,625

The color intensity was assessed by eight test subjects on a scale from 1 (weak) to 5 (very intensive) and the mean values were formed.

Pretreatment with Gluadin WQ (wheat protein hydrolyzate, quaternized)

The experiment was carried out in the same way as for gelatin (see FIG. 1). More intensive colorations were also achieved when pretreatment was carried out with an aqueous solution of 10% by weight Gluadin WQ.

Hair dye Color intensity without pretreatment with pretreatment

Poly Color Brilliance Dark Brown 3.250 4.125

Poly Color Brilliance autumn brown 3,550 4,300

Poly Color Brilliance mahogany 3.5 4.1

Poly Color Brilliance sweet chestnut 3.60 4,400

Poly Color Brilliance Bordeaux Red 3.85 4.550

Claims

claims

1. A process for dyeing hair, characterized in that the hair is pretreated with an aqueous preparation (A) which contains a protein, protein hydrolyzate or protein derivative dissolved therein, is brought into contact with a coloring preparation (B) and after an exposure time with Washes water and / or an aqueous shampoo.

2. The method according to claim 1, characterized in that the aqueous preparation (A) contains 1 - 20 wt .-% of a dissolved protein, protein hydrolyzate or protein derivative.

3. The method according to claim 1 or 2, characterized in that the dye preparation (B) contains oxidation dye precursors and, if appropriate, an oxidizing agent or an oxidation catalyst.

4. The method according to any one of claims 1-3, characterized in that the aqueous preparation (A) contains a protein hydrolyzate or a quaternized protein hydrolyzate and has a pH of 4-6.5.

5. hair dye set, consisting of at least two separately packaged, combined into a sales unit components (A) and (B), characterized in that component (A) is an aqueous preparation with a protein, protein hydrolyzate or protein derivative dissolved therein and the components (B) is a dye preparation with at least one hair dye or dye precursor.

6. Hair dye set according to claim 5, characterized in that component (B) comprises an aqueous dye preparation (B1) containing oxidation dye products and a further component (B2) which contains an oxidizing agent.