Improved indigo-based dye

Abstract

The invention relates to a product and a method for dyeing keratin fibers, in particular human hair, using an indigo or indirubin producing plant powder, isatin and cysteine.

Description

[0001] Improved indigo-based dye

[0002] The invention relates to an agent and a method for coloring keratin-containing fibers, in particular human hair, using an indigo or indirubin-producing plant powder in combination with isatin and cysteine.

[0003] The desire to change one's hair color is a major need for many consumers. To satisfy this need, the cosmetics industry offers a diverse range of products. Hair dyes that achieve particularly long-lasting color with high coverage are usually oxidation dyes. These use oxidizing agents that can damage the hair structure. Certain cationic direct azo dyes are also capable of achieving hair color changes with excellent color fastness properties. However, these azo dyes are synthetic dyes.

[0004] A growing number of consumers are demanding hair dyes and hair coloring processes based on natural dyes, even though these products and processes are often inferior to the aforementioned products and processes in terms of authenticity, coverage and color variety.

[0005] In addition to dyeing with henna, which is obtained from the plant Lawsonia inermis, hair dyeing with plants from which indigo or indirubin can be produced has also been known for a long time.

[0006] State of the art

[0007] There has been no lack of efforts in the state of the art to improve the coloring of keratin fibers, especially human hair, with indigo.

[0008] The addition of natural dyes to oxidative hair dyes is also popular. This involves mixing the coloring cream with an aqueous preparation containing hydrogen peroxide shortly before application to the hair. The coloring cream primarily contains oxidation dye precursors, such as toluene-2,5-diamine sulfate, 4-chlororesorcinol, 2-methylresorcinol, 2-amino-4-hydroxyethylaminoanisole sulfate, 4-amino-2-hydroxytoluene, 4-amino-m-cresol, and m-aminophenol; the natural dye content serves only to provide nuance. The resulting color is essentially a standard oxidative dye with high fastness properties. The problem of poor adhesion of the natural dye plays a minor role with such products.WO2015082482A1 discloses a process for oxidative hair coloring in which pulverized plant parts from indigo-producing plants are used in the presence of hydrogen peroxide, but not oxidation dye precursors. In any case, the hair is damaged by the oxidizing agent.

[0009] When dyeing keratin fibers with indigo, without creating special conditions such as pre- or post-treatment or adding certain active ingredients, a color shift from an initial turquoise-blue tone to a redder and darker tone, creating a purple color impression, has been observed from a concentration of 2% by weight of indigo-producing plant powder in water approximately two weeks after dyeing.

[0010] From DE4211450A1, non-oxidative hair dyes are known which contain isatin in combination with at least one amino acid, for example cysteine, or a water-soluble oligopeptide composed of 2 to 9 amino acids in an aqueous carrier.

[0011] Task

[0012] One object was to provide agents and methods for coloring keratin-containing fibers, particularly human hair, using plants that produce indigo or indirubin, with which a broader range of colorations can be achieved. In particular, colorations beyond the typical indigo blue, especially colorations with a shift into warmer color ranges, were to be provided. A further object of the present invention was to provide agents and methods for coloring keratin-containing fibers, particularly human hair, using plants that produce indigo or indirubin, with which the final color result is obtained as soon as possible after completion of the actual coloring process.

[0013] Surprisingly, it was discovered that, using the dyeing agents described in the patent claims and the dyeing process described in the patent claims, using plants that produce indigo or indirubin in combination with cysteine ​​and isatin, an intense magenta hair color could be achieved directly after the dyeing procedure. Furthermore, the final color result was achieved shortly after completion of the actual dyeing process, and this color result—unlike what is often typical for indigo dyeing—did not change in the days following completion of the dyeing process. Neither the initial turquoise-blue color tone characteristic of indigo nor the final purple tone were formed on the hair fiber.A first subject of the present invention is therefore an agent for the non-oxidative coloring of keratinic fibers, in particular human hair, containing water, cysteine, isatin and at least one indigo or indirubin-producing plant powder i), wherein the agent has a pH of 2.0 to less than 10.0, preferably of 4.0 to 9.0, particularly preferably of 5.0 to 8.0, extraordinarily preferably of 6.7 to less than 7.5, in each case measured at 20°C.

[0014] The terms “colorant according to the invention” and coloring composition (A) are used synonymously in the present application.

[0015] Unless otherwise stated, room temperature refers to a temperature of 20°C.

[0016] All pH values ​​refer to measurements at 20°C.

[0017] Preferred dyes according to the invention are characterized in that the indigo or indirubin producing plant(s) is / are selected from at least one species of the following genera:

[0018] - Indigofera, in particular Indigofera tinctoria, Indigo suffruticosa, Indigofera articulata, Indigofera arrecta, Indigofera heterantha “Gerardiana”, Indigofera argentea or Indigofera longiracemosa;

[0019] - Isatis, especially Isatis tinctoria (woad);

[0020] - Persicaria, especially Persicaria tinctoria (dyer's knotweed);

[0021] - Wrightia, especially Wrightia tinctoria;

[0022] - Calanthe, especially Calanthe veratrifolia; and

[0023] - Baphicacanthus cusia, synonym Strobilanthes cusia.

[0024] Particularly preferred plants producing indigo or indirubin are selected from the genus Indigofera and in particular from Indigofera tinctoria.

[0025] The plants of the aforementioned genera and species contain no or only small amounts of indigo and indirubin. Instead, the plants contain the compound indican, a precursor to indigo and indirubin. The parts of the aforementioned plant genera and species that are rich in indican and also contain indigo or indirubin are the leaves of these plants. For use as dyes for keratin fibers, the plant leaves of the aforementioned plant genera and species are dried and ground, and used as plant powder.

[0026] Plant powders preferred according to the invention have a particle size of less than 500 pm, particularly preferably in the range of 120 pm - 200 pm, extremely preferably in the range of 150 pm - 180 pm. Further plant powders preferred according to the invention have a bulk density in the range of 0.20 - 0.60 g / cm 3, particularly preferably in the range of 0.25 - 0.40 g / cm 3 Other plant powders preferred according to the invention have, based on their weight, a moisture content of less than 10% by weight, preferably 0.1-6.0% by weight, particularly preferably 0.2-3.0% by weight. The moisture content is determined after 3 hours of drying at 105°C.

[0027] According to the invention, it is preferred that the powder of the indigo- or indirubin-producing plant, based on its weight, consists of at least 50 wt.%, preferably at least 80 wt.%, particularly preferably more than 80-100 wt.%, of the leaves of the plant. Further colorants preferred according to the invention are characterized in that the powder of the indigo- or indirubin-producing plant has a particle size of less than 500 pm, particularly preferably in the range of 120 pm-200 pm, extremely preferably in the range of 150 pm-180 pm, and also a bulk density in the range of 0.20-0.60 g / cm 3 , particularly preferably in the range of 0.25 - 0.40 g / cm 3 and, based on its weight, has a moisture content of less than 10 wt.%, preferably 0.1 - 6.0 wt.%, particularly preferably 0.2 - 3.0 wt.%.

[0028] Further preferred colorants according to the invention are characterized in that the powder of the indigo or indirubin-producing plant contains the compound indican in an amount of 2-5% by weight, preferably 2.5-4.5% by weight, particularly preferably 3-4.1% by weight, based on the weight of the powder.

[0029] Further coloring agents preferred according to the invention are characterized in that at least one indigo or indirubin-producing plant powder i) is contained in a total amount of 1 - 80 wt.%, preferably 2 - 50 wt.%, particularly preferably 3 - 25 wt.%, extraordinarily preferably 4 - 15 wt.%, further extraordinarily preferably 5 - 10 wt.%, further extraordinarily preferably 6 - 7 wt.%, based on the weight of the agent.

[0030] Further coloring agents preferred according to the invention are characterized in that powdered leaves of Indigofera tinctoria are contained in an amount of 1-80 wt.%, preferably 2-50 wt.%, particularly preferably 3-25 wt.%, extraordinarily preferably 4-15 wt.%, further extraordinarily preferably 5-10 wt.%, further extraordinarily preferably 6-7 wt.%, based on the weight of the agent.

[0031] Colorants preferred according to the invention are characterized in that cysteine ​​is contained in an amount of 0.1 - 5.0 wt.%, preferably 0.5 - 3.0 wt.%, particularly preferably 0.8 - 2.0 wt.%, extraordinarily preferably 1.0 - 1.5 wt.%, based on the weight of the agent.

[0032] Cysteine, as a chiral amino acid, possesses a stereogenic center and can occur in mirror-image form, namely in the form of L-cysteine ​​and D-cysteine. Both L-cysteine ​​and D-cysteine, as well as mixtures thereof, are encompassed by the present invention. Within the scope of the present invention, both possible enantiomers can therefore be used equally as specific compounds or as mixtures thereof, particularly as racemates. However, it is particularly advantageous according to the invention to use the naturally occurring isomer form, in this case L-cysteine.

[0033] Colouring agents which are extraordinarily preferred according to the invention are characterized in that L-cysteine ​​is contained in an amount of 0.1 - 5.0% by weight, preferably 0.5 - 3.0% by weight, particularly preferably 0.8 - 2.0% by weight, extraordinarily preferably 1.0 - 1.5% by weight, based on the weight of the agent.

[0034] An aqueous solution of cysteine ​​reacts acidically. A 1 wt% solution of L-cysteine ​​in deionized water has a pH of 6.49, measured at 20°C. Cysteine ​​is therefore not an alkalizing agent.

[0035] Powders from the leaves of Indigofera tinctoria, which are preferably used according to the invention, react approximately neutrally in aqueous dispersion, with slight deviations between a slightly acidic and a slightly alkaline pH range. A 5 wt. % dispersion of ground leaves of Indigofera tinctoria in deionized water has a pH of 6.6 to 7.4, preferably 6.8 to 7.2, particularly preferably 6.9 to 7.1, each measured at 20°C.

[0036] Further coloring agents preferred according to the invention are characterized in that isatin is contained in an amount of 0.01 - 1.0 wt.%, preferably 0.05 - 0.5 wt.%, particularly preferably 0.08 - 0.3 wt.%, extraordinarily preferably 0.1 - 0.2 wt.%, based on the weight of the agent.

[0037] For the effects according to the invention, it has proven particularly advantageous if cysteine ​​is present in molar excess to isatin.

[0038] Further preferred coloring agents according to the invention are therefore characterized in that cysteine ​​is contained in molar excess to isatin.

[0039] Particularly preferred colorants according to the invention are characterized in that the molar ratio of cysteine ​​to isatin is 1.5 to 20, preferably 3 to 18, particularly preferably 5 to 15, extremely preferably 10 to 13.

[0040] The dyes according to the invention also contain water. The water serves to disperse the plant powder and to dissolve the indican contained therein, making it accessible for reaction to form indigo and indirubin. Preferred dyes according to the invention are characterized by the presence of water in an amount of 19.9-95.0 wt.%, preferably 30.0-90.0 wt.%, particularly preferably 50.0-88.0 wt.%, and extremely preferably 60.0-85.0 wt.%, based on the weight of the dye.

[0041] The colorants according to the invention have a pH of 2.0 to less than 10.0, preferably from 4.0 to 9.0, particularly preferably from 5.0 to 8.0, extraordinarily preferably from 6.7 to less than 7.5, in each case measured at 20°C.

[0042] A dispersion of 5 wt.% ground leaves of Indigofera tinctoria in deionized water, in which 1 wt.% L-cysteine ​​and 0.1 wt.% isatin are also dissolved, has a pH of 7.4, measured at 20°C, whereby the quantities refer to the weight of the total aqueous preparation.

[0043] Very good dyeing results are already achieved in the pH range around the pH spontaneously established in the mixture of ground leaves of Indigofera tinctoria, cysteine ​​and isatin in deionized water of 7.0 to 7.4, i.e. in particular from 5.0 to 8.0, preferably from 6.7 to less than 7.5, each measured at 20°C.

[0044] In a preferred embodiment of the dyeing process according to the invention, the desired pH of the aqueous dyeing composition (A) is adjusted using an acid or a base. Preferred acids are selected from citric acid, lactic acid, gluconic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, galactaric acid (mucous acid), tartaric acid, malic acid, sulfuric acid, and phosphoric acid, as well as mixtures of these acids. Preferred bases are sodium hydroxide, potassium hydroxide, arginine, lysine, monoethanolamine, triethanolamine, 2-amino-2-methylpropan-1-ol, and mixtures of these bases.

[0045] In a further preferred embodiment of the dyeing process according to the invention, the desired pH of the aqueous dyeing composition (A) is adjusted with the aid of a buffer system selected from a mixture of a medium-strength or weak acid with its conjugate or corresponding base (or the respective salt) and a mixture of a medium-strength or weak base with its conjugate or corresponding acid.

[0046] According to the invention, preferred suitable corresponding acid-base pairs are those which stabilize the aqueous dyeing composition (A) used according to the invention in the pH range from 2.0 to less than 10.0, preferably from 4.0 to 9.0, particularly preferably from 5.0 to 8.0, extraordinarily preferably from 6.7 to less than 7.5, in each case measured at 20°C.

[0047] Particularly preferred buffer systems according to the invention for the aqueous dyeing composition (A) used according to the invention are selected from

[0048] - Ammonia / ammonium salt mixtures, wherein the ammonium salt is preferably selected from ammonium chloride, ammonium bromide, ammonium hydrogen sulfate, ammonium sulfate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, ammonium bicarbonate, ammonium carbonate, ammonium nitrate, ammonium acetate, ammonium glycolate, ammonium gluconate, ammonium tartrate, ammonium lactate, and mixtures of these ammonium salts, particularly preferably selected from ammonium chloride, ammonium hydrogen sulfate, ammonium sulfate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, ammonium bicarbonate, and ammonium carbonate, extremely preferably selected from ammonium chloride,

[0049] - mixtures of hydrogen phosphate and dihydrogen phosphate, in particular the alkali metal salts of hydrogen phosphate and dihydrogen phosphate, particularly preferably the sodium salts and / or the potassium salts of hydrogen phosphate and dihydrogen phosphate,

[0050] - mixtures of alkali metal bicarbonate with alkali metal carbonate, in particular mixtures of sodium or potassium bicarbonate with sodium or potassium carbonate,

[0051] - mixtures of citric acid and its salts, in particular the alkali metal citrates, in particular the sodium salts, in particular trisodium citrate,

[0052] - mixtures of tartaric acid and its salts, in particular alkali metal tartrates, in particular potassium salts, in particular potassium hydrogen tartrate,

[0053] - mixtures of phthalic acid and its salts, in particular potassium salts, in particular potassium hydrogen phthalate,

[0054] - mixtures of lactic acid and its salts, in particular lactic acid / sodium lactate mixtures,

[0055] - mixtures of gluconic acid and its salts, in particular gluconic acid / sodium gluconate mixtures,

[0056] - mixtures of succinic acid and its salts, in particular the sodium salts, in particular sodium hydrogen succinate and disodium succinate, and

[0057] - mixtures of malic acid and its salts, in particular the sodium salts, in particular sodium hydrogen malate and disodium malate, and

[0058] - Ammonia / ammonium salt mixtures, wherein the ammonium salt is preferably selected from ammonium chloride, ammonium bromide, ammonium hydrogen sulfate, ammonium sulfate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, ammonium bicarbonate, ammonium carbonate, ammonium nitrate, ammonium acetate, ammonium glycolate, ammonium gluconate, ammonium tartrate, ammonium lactate, and mixtures of these ammonium salts, particularly preferably selected from ammonium chloride, ammonium hydrogen sulfate, ammonium sulfate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, ammonium bicarbonate, and ammonium carbonate, extremely preferably selected from ammonium chloride.

[0059] Other buffer systems, such as acetic acid / sodium acetate, are also suitable in principle according to the invention. However, due to the vinegar odor, such a buffer is not acceptable for the production of a commercial cosmetic product.

[0060] For varying the pH value, further preferred dyeing agents and dyeing processes according to the invention are characterized in that the aqueous dyeing composition (A) contains a buffer system for pH adjustment, selected from a mixture of a medium-strength or weak acid or base with its conjugate or corresponding base or corresponding acid.

[0061] Further dyeing processes preferred according to the invention are characterized in that the aqueous dyeing composition (A) contains a buffer system selected from an ammonia / ammonium salt mixture for pH adjustment in the basic range. Preferred ammonium salts that buffer the strongly basic pH of the aqueous ammonia solution to a less basic pH are selected from ammonium chloride, ammonium bromide, ammonium hydrogen sulfate, ammonium sulfate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, ammonium bicarbonate, ammonium carbonate, ammonium nitrate, ammonium acetate, ammonium glycolate, ammonium gluconate, ammonium tartrate, ammonium lactate, and mixtures of these ammonium salts. Ammonium chloride, ammonium hydrogen sulfate, ammonium sulfate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, ammonium bicarbonate, and ammonium carbonate are particularly preferred. Ammonium chloride is extremely preferred.

[0062] In principle, other buffer systems are also suitable.

[0063] Further dyeing processes preferred according to the invention are characterized in that the aqueous dyeing composition (A) contains a buffer system selected from a hydrogen phosphate salt / dihydrogen phosphate salt mixture for pH adjustment. Suitable salts are the sodium salts and the potassium salts of hydrogen phosphate and dihydrogen phosphate. With hydrogen phosphate salt / dihydrogen phosphate salt mixtures, pH values ​​in the range from 7.1 to about 8.2 can be adjusted.

[0064] For higher pH values ​​up to pH < 10.0, mixtures of sodium or potassium bicarbonate with sodium or potassium carbonate are suitable. Further dyeing processes preferred according to the invention are therefore characterized in that the aqueous dyeing composition (A) contains a buffer system selected from a mixture of sodium or potassium bicarbonate with sodium or potassium carbonate for pH adjustment. Suitable salts are the sodium salts and the potassium salts of bicarbonate and carbonate. With bicarbonate salt / carbonate salt mixtures, pH values ​​in the range from approximately 9.0 to < 10.0 can be adjusted.

[0065] The specialist can obtain the appropriate weights of buffer salts to adjust the desired pH value from the relevant manuals.

[0066] Preferred dyeing agents and dyeing processes according to the invention are further characterized in that no hydrogen peroxide is used in them.

[0067] Preferred dyes and dyeing processes according to the invention are further characterized in that they do not contain any ions or compounds of metals other than alkali metals and alkaline earth metals. The content of metal ions other than alkali metal ions and alkaline earth metal ions, which are present in trace amounts in the water used, e.g., in tap water or municipal water, is not taken into account. Tap water can contain an average of 2 mg of copper ions per liter, i.e., approximately 0.0002 wt.% copper ions. The maximum concentration of metal ions other than alkali metal ions and alkaline earth metal ions in preferred dyes according to the invention is 0.00001 to 0.002 wt.%, preferably 0.0001 to 0.001 wt.%, particularly preferably a maximum of 0.0007 wt.%, in each case based on the dye.

[0068] If salts are to be present, the salts of alkali metals and alkaline earth metals, in particular the salts of sodium, potassium and magnesium, preferably the salts of sodium and potassium, are suitable according to the invention.

[0069] According to the invention, salts and compounds of aluminum, transition metals, and lanthanides are particularly undesirable. These metals, even in their elemental form, are not used in the dyeing agents and dyeing processes according to the invention.

[0070] Conventional dyes and dyeing processes using natural dyes often use compounds, especially salts, of metals other than alkali metals and alkaline earth metals to improve the adhesion of the natural dye to the keratin fibers. The present dyes and dyeing processes according to the invention can dispense with the use of ions and compounds of metals other than alkali metals and alkaline earth metals.The present invention further provides a method for the non-oxidative coloring of keratin fibers, in particular human hair, which comprises the following process steps in the given order: a) providing an aqueous coloring composition (A) which contains at least one indigo or indirubin-producing plant powder i), further cysteine ​​and further isatin and has a pH of 2.0 to less than 10.0, preferably from 4.0 to 9.0, particularly preferably from 5.0 to 8.0, extraordinarily preferably from 6.7 to less than 7.5, in each case measured at 20°C, b) applying the aqueous coloring composition (A) to the keratin fibers, c) allowing it to act for a time of 30 seconds to 60 minutes, preferably 5 to 45 minutes, particularly preferably 15 to 30 minutes, d) rinsing the keratin fibers with water, e) optionally drying the keratin fibers, wherein no hydrogen peroxide is used in the process becomes.

[0071] "Non-oxidative" is understood according to the invention to mean that no oxidizing agents other than atmospheric oxygen are used in the agents, kits, and methods according to the invention. In particular, the oxidizing agents hydrogen peroxide, persulfates, perbromates, percarbonates, perborates, and percarbamides are excluded. Atmospheric oxygen does not constitute an oxidizing agent in the context of the invention.

[0072] In process step b), an aqueous dyeing composition (A) is applied to the keratin fibers to be dyed, which are preferably dry, which has a pH in the range from 2.0 to less than 10.0, preferably from 4.0 to 9.0, particularly preferably from 5.0 to 8.0, extraordinarily preferably from 6.7 to less than 7.5, in each case measured at 20°C.

[0073] Surprisingly, it was found that the temporal development of the coloring result on the keratin fibers can be accelerated if the coloring composition (A) is allowed to act with the addition of heat, for example, using a heat lamp, a hairdryer, or a hairdryer. Preferred coloring methods according to the invention are therefore characterized in that the coloring composition (A) is allowed to act with the addition of heat. Particularly preferred coloring methods according to the invention are characterized in that the coloring composition (A) is allowed to act with the addition of heat at a temperature of 25-60°C, particularly preferably at a temperature of 30-50°C, extremely preferably at a temperature of 35-40°C.

[0074] With regard to further preferred embodiments of the dyeing processes according to the invention, what has been said regarding the dyeing agents and dyeing compositions (A) according to the invention applies mutatis mutandis.

[0075] In order to preserve the hair-protecting potential of natural dyes, the claimed method is preferably limited to those methods in which the keratin fibers have not been treated with an oxidizing agent within a period of up to 7 days prior to the application of the dyeing composition (A) according to the invention.

[0076] Oxidizing agents commonly used in hair cosmetics, but which are not intended to be used in hair treatments according to the invention, even as pretreatments, include hydrogen peroxide, persulfates, perbromates, percarbonates, perborates, and percarbamides. The oxygen contained in ambient air does not constitute an oxidizing agent in the context of the invention.

[0077] In order to preserve the hair-protecting potential of natural dyes, preferred methods according to the invention are limited to those methods in which the keratin fibers have not been treated with a keratin-reducing compound within a period of up to 7 days prior to the application of the coloring composition (A) according to the invention.

[0078] The keratin fibers are preferably dried after rinsing out the coloring composition (A). Drying can be carried out without actively applying heat. However, drying can also be carried out with the application of heat at a temperature of 25–120°C, particularly preferably at a temperature of 30–80°C, and extremely preferably at a temperature of 35–60°C. Heat is preferably applied using a heat lamp, a drying rod, a hair dryer, a straightening iron, or a hair dryer.

[0079] A further feature of the dyeing process according to the invention is that the dyeing composition (A) is allowed to act on the keratin fibers after application thereto for a time of 30 seconds to 60 minutes, preferably 5 to 45 minutes, particularly preferably 20 to 35 minutes, extraordinarily preferably 25 to 30 minutes.

[0080] After the exposure time for the coloring composition (A) has elapsed, the keratin fibers are rinsed with water to wash out the coloring composition (S).

[0081] Optionally, the keratin fibers can be dried after this rinsing step. Drying can be done with an absorbent cloth, such as a towel. Towel-dried hair can optionally be partially or completely dried with a hairdryer or other heat source. Allowing the keratin fibers to air dry is also possible. Other preferred coloring methods according to the invention are characterized by the fact that they do not use oxidation dye precursors. Typical oxidation dye precursors are p-aminophenol, 4-amino-3-methylphenol, 4-amino-2-aminomethylphenol, 4-amino-2-(1,2-dihydroxyethyl)phenol, 4-amino-2-(diethylaminomethyl)phenol, 2-(2,5-diaminophenyl)ethanol, 2-(1,2-dihydroxyethyl)-p-phenylenediamine, N,N-bis-(2-hydroxyethyl)-p-phenylenediamine, N-(4-amino-3-methylphenyl)-N-[3-(1H-imidazol-1-yl)propyl]amine, N,N'-bis-(2-hydroxyethyl)-N,N'-bis-(4-aminophenyl)-1,3-diamino-propan-2-ol,Bis-(2-hydroxy-5-aminophenyl)methan, 1 ,3-Bis-(2,5-diaminophen- oxy)propan-2-ol, N,N’-Bis-(4-aminophenyl)-1 ,4-diazacycloheptan, 1 ,10-Bis-(2,5-diaminophenyl)- 1 ,4,7,10-tetraoxadecan, 2,4,5,6-Tetraaminopyrimidin, 4-Hydroxy-2,5,6-triaminopyrimidin, 2-Hydro- xy-4,5,6-triaminopyrimidin, 2,3-Diamino-6,7-dihydro-1 H,5H-pyrazolo-[1 ,2-a]-pyrazol-1-on, 3-Amino- phenol, 5-Amino-2-methylphenol, 3-Amino-2-chlor-6-methylphenol, 2-Hydroxy-4-aminophenoxy- ethanol, 5-Amino-4-chlor-2-methylphenol, 5-(2-Hydroxyethyl)-amino-2-methylphenol, 2,4-Dichlor-3- aminophenol, 2-Aminophenol, 3-Phenylendiamin, 2-(2,4-Diaminophenoxy)ethanol, 1 ,3-Bis(2,4-di- aminophenoxy)propan, 1-Methoxy-2-amino-4-(2-hydroxyethylamino)benzol, 1 ,3-Bis(2,4-diamino- phenyl)propan, 2, 6-Bis(2'-hydroxyethylamino)-1 -methylbenzol, 2-({3-[(2-Hydroxyethyl)amino]-4- methoxy-5-methylphenyl}amino)ethanol, 2-({3-[(2-Hydroxyethyl)amino]-2-methoxy-5-methyl- phenyl}amino)ethanol, 2-({3-[(2-Hydroxyethyl)amino]-4,5-dimethylphenyl}amino)ethanol,2-[3-morpholin-4-ylphenyl)amino]ethanol, 3-amino-4-(2-methoxyethoxy)-5-methylphenylamine, 1-amino-3-bis-(2-hydroxyethyl)aminobenzene, resorcinol, 2-methylresorcinol, 4-chlororesorcinol, 1,2,4-trihydroxybenzene, 2-amino-3-hydroxypyridine, 3-amino-2-methylamino-6-methoxypyridine, 2,6-dihydroxy-3,4-di-methylpyridine, 3,5-diamino-2,6-dimethoxypyridine, 1-phenyl-3-methylpyrazol-5-one, 1-naphthol, 1,5-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 4-Hydroxyindole, 6-Hydroxyindole, 7-Hydroxyindole, 4-Hydroxyindoline, 6-Hydroxyindoline and 7-Hydroxyindoline.,

[0082] The dye compositions (A) according to the invention and those preferred according to the invention may optionally contain further additives to optimize the application properties of these compositions. Preferred additives are, in particular, thickeners, which ensure that the dye composition (A) adheres better to the hair during application.

[0083] Coloring compositions (A) used particularly preferably according to the invention contain at least one or more hydrophilic thickeners, which are preferably selected from polysaccharides that may be chemically and / or physically modified. Compounds from the group of polysaccharides are particularly preferred as hydrophilic thickeners according to the invention, since the basic structures of the polysaccharides are of natural origin and biodegradable. Preferred hydrophilic polysaccharide thickeners are selected from celluloses, cellulose ethers of C1-C4 alcohols, cellulose esters, xanthan gum, alginic acids (and their corresponding physiologically acceptable salts, the alginates), agar agar (with the polysaccharide agarose present in agar agar as the main constituent), starch fractions and starch derivatives such as amylose, amylopectin and dextrins, karaya gum, locust bean gum, gum arabic, pectins, dextrans and guar gum, and mixtures thereof.

[0084] Cellulose ethers of C1-C4 alcohols and cellulose esters preferred according to the invention are selected from methylcelluloses, ethylcelluloses, hydroxyalkylcelluloses (such as hydroxyethylcellulose), methylhydroxyalkylcelluloses and carboxymethylcelluloses (such as those with the INCI name Cellulose Gum) and their physiologically acceptable salts.

[0085] In preferred embodiments, xanthan gum is included as a hydrophilic thickener for reliable viscosity adjustment and residue-free application to keratin fibers and the scalp. In further preferred embodiments, carboxymethylcellulose (preferably carboxymethylcellulose with the INCI name Cellulose Gum) is included as a hydrophilic thickener for reliable viscosity adjustment and residue-free application to keratin fibers and the scalp. In a preferred embodiment, carboxymethylcellulose can be included as the sole hydrophilic thickener. A combination of carboxymethylcellulose and hydroxyethylcellulose is particularly preferred.

[0086] A combination of carboxymethylcellulose and xanthan (preferably xanthan with the INCI name Xanthan Gum) may also be preferred according to the invention.

[0087] Particularly preferred dyeing compositions (A) according to the invention contain at least one hydrophilic thickener in a total amount of 0.1 to 5 wt.%, preferably 0.5 to 4 wt.%, more preferably 1 to 3.5 wt.% and most preferably 1.2 to 2 wt.%, in each case based on the weight of the respective dyeing composition (A).

[0088] In a further preferred embodiment of the present invention, the coloring compositions (A) according to the invention contain, in each case based on their weight, 0.1 to 3% by weight, preferably 0.5 to 2.5% by weight, more preferably 1.2 to 2.0% by weight, of xanthan gum.

[0089] In a further preferred embodiment of the present invention, the dyeing compositions (A) according to the invention contain, in each case based on their weight, 0.1 to 4% by weight, preferably 1 to 2.8% by weight, of carboxymethylcellulose.

[0090] In a further preferred embodiment of the present invention, the dyeing compositions (A) according to the invention contain, in each case based on their weight, 0.1 to 3% by weight, preferably 0.5 to 2.5% by weight, more preferably 1.2 to 2.0% by weight, of hydroxyethylcellulose.

[0091] Particularly preferred dyeing compositions (A) according to the invention contain at least one organic solvent having a phenyl group in the molecule. This solvent is preferably selected from phenoxyethanol, benzyl alcohol, and mixtures thereof. Surprisingly, it has been found that such aromatic solvents can have a positive effect on the dyeing results of the dyeing process according to the invention; this was observed in particular when the dyeing composition (A) contains such an aromatic solvent. In a further preferred embodiment of the present invention, the dyeing compositions (A) preferred according to the invention contain, in each case based on their weight, 0.1 to 3 wt. %, preferably 0.5 to 2.5 wt. %, more preferably 0.8 to 1.0 wt. %, of at least one organic solvent having a phenyl group in the molecule.In a further preferred embodiment of the present invention, the dyeing compositions (A) according to the invention contain, in each case based on their weight, 0.1 to 3% by weight, preferably 0.5 to 2.5% by weight, more preferably 0.8 to 1.0% by weight, of at least one organic solvent selected from phenoxyethanol, benzyl alcohol and mixtures thereof.

[0092] Particularly preferred dyeing compositions (A) according to the invention are characterized in that they contain at least one aliphatic solvent selected from C1-C4 alkanols and C2-C4 polyols, in particular selected from ethanol, isopropanol, n-propanol, ethylene glycol, 1,2-propanediol, glycerol and 1,3-butylene glycol, and mixtures of these solvents, but only in a total amount of 0.01-8 wt.%, preferably 0.1-6 wt.%, particularly preferably 0.5-4 wt.%, in each case based on the weight of the dyeing composition (A).

[0093] Other dyeing compositions (A) which are particularly preferred according to the invention are characterized in that they do not contain an aliphatic solvent selected from C1-C4 alkanols and C2-C4 polyols.

[0094] In order to make the coloring compositions (A) according to the invention also sensorially attractive for the user, further coloring compositions (A) which are particularly preferred according to the invention are characterized in that they contain at least one perfume oil which contains at least one fragrance compound or odoriferous compound.

[0095] Dyeing compositions (A) which are extraordinarily preferred according to the invention are characterized in that they contain at least one fragrance in a total amount of 0.01 - 5 wt.%, preferably 0.1 - 3 wt.%, particularly preferably 0.5 - 2 wt.%, extraordinarily preferably 1 - 1.5 wt.%, in each case based on the weight of the dyeing composition (A).

[0096] Implementation examples

[0097] The exemplary embodiments presented below are intended to explain the subject matter of the invention in more detail without limiting it thereto.

[0098] As an example of the invention, the following inventive dyeing composition (A) was prepared: Table 1: Inventive dyeing composition (A-1)

[0099] * powdered leaves of Indigofera tinctoria, pH of the 5 wt% dispersion in water:

[0100] 6.8 to 7.2 (20°C)

[0101] 2.5 g of indigo powder were dispersed in 46.95 grams of demineralized water, and 0.5 g of L-cysteine ​​and 0.05 g of isatin were added and dissolved. While stirring, this dispersion was heated on a stir plate to approximately 37 °C ± 1 °C. Once this temperature was reached, a strand of buffalo belly hair (round-tied, approximately 8 cm of free hair) was placed in this dispersion (dye composition (A-1)) for 30 minutes while stirring.

[0102] The liquor ratio, i.e. the weight of dye per gram of hair, was 50 g of dye per 1 g of hair (50:1).

[0103] After the dyeing process, the hair strands were rinsed under running deionized water for 30 seconds and combed 20 times (20°C).

[0104] The hair strands were then dried with a commercially available hair dryer at a defined distance (d = 10 cm) and a defined temperature (T = 80 ± 5 °C) with 20 combs.

[0105] Determination of staining results using spectrophotometric measurements

[0106] All colorimetric measurements were performed using the Spectraflash SF 600 colorimetric device from Datacolor.

[0107] The color difference, also known as dE or AE, can be easily determined colorimetrically using a colorimeter that measures colors in the L*, a*, b* color space, for example a Datacolor Spectraflash SF 600 colorimeter.

[0108] The L*,a*,b* color space refers to the CIELAB color space. The L value represents the brightness of the color (black-white axis); the higher the L value, the brighter the color. The a value represents the red-green axis of the system; the higher this value, the more the color is shifted toward red. The b value represents the yellow-blue axis of the system; the higher this value, the more the color is shifted toward yellow.

[0109] The color shift AE, i.e. the color difference between two (hair) colors, for each of which an L*, a*, b* value combination has been determined, is calculated according to the following formula:

[0110] AE = (AL 2 + Aa2 + From 2 ) 05

[0111] The larger the value for AE, the more pronounced the color difference.

[0112] A D65 illuminant and a diffuse / 8° optical configuration were used for the spectrophotometer measurements. The spectral reflectance data for each sample from 380 nm to 700 nm were converted to colorimetric data using DCI Color software. Reflectance measurements were determined for each hair sample, with the average of four measurements recorded.

[0113] The color difference (AE) between undyed strand and dyed strand (with indigo / cysteine / isatin or with indigo alone) was calculated according to the following formula:

[0114] Lv, av, bv: colorimetric values ​​for dyed strands

[0115] Ln, an, bn: Colorimetric values ​​for undyed strands

[0116] In order to further understand the temporal development of the final color, measurements were taken on day 0 directly after coloring and 14 days after coloring and compared.

[0117] Table 2: L*, a*, b*, AE values ​​of indigo stains with cysteine / isatin and indigo alone

[0118] The differences between the control strand and the strands with the addition of cysteine / isatin immediately after staining at 37 °C (day 0) and 14 days after staining are shown below (mean values).

[0119] The addition of cysteine ​​and isatin to the dispersion of Indigofera tinctoria leaf powder results in an intense magenta tone on the hair fiber after coloring, rather than a blue-turquoise tone (see Table 2). The change in the color tone of this strand in the two weeks after coloring becomes even more uniform overall, but is negligible (AE of approximately 1 to 3).

[0120] In the coloring according to the invention described above, in contrast to the control, the magenta tone can be observed on the hair strand directly after the treatment.

[0121] Influence of dyeing temperature

[0122] The same coloring, performed at 20°C, shows a pinkish tint immediately after treatment. This was not quantifiable due to residual moisture. However, an irregular, stronger red-magenta tone developed during subsequent blow-drying (temperature at 5 cm from the hair dryer: 96°C, at 15 cm from the hair dryer: 79°C). The color difference between coloring at 37°C followed by blow-drying and coloring at 20°C followed by blow-drying was AE = 12.7.

[0123] Table 3: L*, a*, b*, AE values ​​of indigo stains with cysteine / isatin and indigo alone, staining at 20°C and blow-drying

[0124] The differences between the control strand and the strands with addition of cysteine / isatin immediately after staining at 20 °C (day 0) after staining are shown below (mean values). Influence of the pH value of the dye on the color result

[0125] The following shows how the pH value of the dye dispersion affects the color result.

[0126] The dyes are prepared and the strands are dyed according to the process described above. A pH of 7.4 is spontaneously established in the dispersion (A-1) of indigo leaves, 1 wt.% cysteine, and 0.1 wt.% isatin in water. The pH of other dye dispersions according to the invention was adjusted to 3, 5, 8, and 10 with sodium hydroxide solution or hydrochloric acid, each measured at 20°C. The dyeing was carried out at 37°C. Following dyeing, all strands were washed and dried according to the usual protocol (see above). The color results were compared with those achieved at the "spontaneous" pH of 7.4. The dye dispersion with a pH of 10 is not according to the invention (V-1).

[0127] Table 4: L*, a*, b*, AE values ​​of indigo stains with cysteine ​​and isatin at 37 °C and different pH values ​​directly after staining (day 0)

[0128] It can be observed that the color intensity and magenta tone increase at pH 5. The result of the dyeing dispersion at pH 3, with an AE of 5.8, loses both darkness (intensity) and redness compared to the dispersion with the spontaneous pH of 7.4. At pH 8, only the darkness (intensity) increases – the a* value, which represents the red intensity, decreases slightly compared to the strand dyed at pH 7.4. At pH 10 (not according to the invention), the desired color is not visible on the hair fiber.

[0129] The data presented suggest that indigo, in combination with cysteine ​​and isatin in the dye dispersion at pH 5, produces the darkest, most intense, and most reddish color. The dye dispersion in the slightly alkaline range (pH 8) is closest to the color result at the spontaneous pH value (7.4) (ΔE = 2.9). At a pH of 10, the dispersion does not produce a color result comparable to the spontaneously occurring pH value of 7.4. Comparison of the dyes according to the invention with the teaching of DE4211450A1

[0130] The difference between a dye known from DE4211450A1, containing isatin and cysteine, and a dye according to the invention, containing indigo plant leaves, isatin and cysteine, will be illustrated by the following series of measurements.

[0131] To prepare the reference dye according to DE4211450A1, 0.5 g of (R)-(+)-cysteine ​​(1 wt% of the total solution) and 0.05 g of isatin (0.1 wt% of the total solution) were dissolved in 49.45 grams of demineralized water.

[0132] Test series A: This solution was then heated to 37 °C, a strand of hair was placed in the solution for 30 minutes and stirred constantly at 37 °C ± 1 °C (liquor ratio: 50 ml for 1 g of hair strand; pH: approx. 6.7, measured at 20 °C).

[0133] Experimental series B: A strand of hair was placed in another previously described, unheated cysteine-isatin solution for 30 minutes and stirred constantly at 20 °C (liquor ratio: 50 ml for 1 g of hair strand; pH: approx. 6.7, measured at 20 °C).

[0134] After dyeing processes A or B, the solution was washed off the strand (30 seconds under running deionized water, twenty combs at 20°C) and the strand was dried (hair dryer, distance d = 10 cm, temperature: T = 80 ± 5 °C, twenty combs).

[0135] The result is compared with the color result of the strand treated with the colorant A-1 according to the invention at 37 °C or at 20 °C, see Tables 5 and 6.

[0136] Table 5: Comparison between indigo and cysteine ​​and isatin treatment according to the invention at 37 °C and non-inventive treatment with cysteine ​​and isatin at 37 °C immediately after rinsing and blow-drying (L*, a*, b* values ​​are shown)

[0137] The non-inventive treatment of the strand results in a significantly lighter color (higher L* value) that tends less toward reddish and more toward yellow (AE = 36.3). Table 6: Comparison between the inventive treatment with indigo, cysteine, and isatin at 20°C and the non-inventive treatment with cysteine ​​and isatin at 20°C immediately after rinsing and blow-drying (L*, a*, b* values ​​are shown).

[0138] The treatment of the strand not according to the invention results in a coloration with a significantly lighter shade (higher L* value) that tends less towards the reddish-magenta direction (AE = 33.6).

[0139] Influence of the reducing agent

[0140] The following shows how replacing cysteine ​​with another reducing agent affects the color result.

[0141] The dyes were prepared and the strands were dyed according to the process described above. In addition to the inventive dispersion (A-1) consisting of 5 wt.% indigo leaves, 1 wt.% cysteine, and 0.1 wt.% isatin in water, a comparison dispersion (V-2) consisting of 5 wt.% indigo leaves, 1 wt.% ascorbic acid, and 0.1 wt.% isatin in water was prepared. One batch was dyed onto strands of hair at 20°C and another batch at 37°C. Both strands were then washed and dried according to the usual protocol (see above). The pH of the dispersion containing indigo, ascorbic acid, and isatin was 5.0 (measured at 20°C) spontaneously, i.e., without the addition of additional pH adjusters. The color results achieved are summarized in Table 7 and Table 8.

[0142] Table 7: Comparison between indigo, cysteine, and isatin treatment according to the invention at 37 °C and non-inventive treatment with indigo, ascorbic acid, and isatin at 37 °C immediately after rinsing and blow-drying (L*, a*, and b* values ​​are shown) Using ascorbic acid instead of cysteine ​​results in a slightly less dark, redder, and more bluish color when stained at 37 °C. The two color results differ by AE = 8.1.

[0143] Table 8: Comparison between treatment according to the invention with indigo and cysteine ​​and isatin at 20 °C and non-treatment according to the invention with indigo and ascorbic acid and isatin at 20 °C directly after rinsing and blow-drying (L*, a*, b* values ​​are shown)

[0144] The difference between the color results according to the invention and those not according to the invention is greater when dyed at 20°C than when dyed at 37°C: AE = 19.6 instead of 8.1. The strand treated with ascorbic acid (not according to the invention) is significantly lighter, less red, and more yellow than the strand dyed according to the invention.

Claims

Patent claims 1. An agent for the non-oxidative coloring of keratin fibers, in particular human hair, containing water, cysteine, isatin and at least one indigo or indirubin-producing plant powder i), wherein the agent has a pH of 2.0 to less than 10.0, preferably of 4.0 to 9.0, particularly preferably of 5.0 to 8.0, extraordinarily preferably of 6.7 to less than 7.5, in each case measured at 20°C.

2. Agent for non-oxidative staining according to claim 1, characterized in that cysteine ​​is contained in molar excess to isatin.

3. A non-oxidative dyeing agent according to claim 2 or 3, characterized in that the indigo or indirubin producing plant(s) is / are selected from at least one species of the following genera: - Indigofera, in particular Indigofera tinctoria, Indigo suffruticosa, Indigofera articulata, Indigofera arrecta, Indigofera heterantha “Gerardiana”, Indigofera argentea or Indigofera longiracemosa; - Isatis, especially Isatis tinctoria (woad); - Persicaria, especially Persicaria tinctoria (dyer's knotweed); - Wrightia, especially Wrightia tinctoria; - Calanthe, especially Calanthe veratrifolia; and - Baphicacanthus cusia, synonym Strobilanthes cusia, wherein the indigo or indirubin producing plant(s) is / are preferably selected from the genus Indigofera and in particular from Indigofera tinctoria.

4. Agent according to one of claims 1-3, characterized in that the powder of the indigo or indirubin-producing plant consists, based on its weight, of at least 50% by weight, preferably at least 80% by weight, particularly preferably more than 80-100% by weight, of the leaves of the plant.

5. Agent according to one of claims 1 to 4, characterized in that the powder of the indigo or indirubin-producing plant contains indican in an amount of 2 - 5 wt.%, preferably 2.5 - 4.5 wt.%, particularly preferably 3 - 4.1 wt.%, based on the weight of the powder.

6. Agent according to one of claims 1 - 5, characterized in that at least one indigo or indirubin producing plant powder i) in a total amount of 1 - 80 wt.%, preferably 2 - 50 wt.%, particularly preferably 3 - 25 wt.%, extraordinarily preferably 4 - 15 wt.%, further extraordinarily preferably 5 - 10 wt.%, further extraordinarily preferably 6 - 7 wt.%, based on the weight of the agent.

7. Agent according to one of claims 1-6, characterized in that powdered leaves of Indigofera tinctoria are contained in an amount of 1-80 wt.%, preferably 2-50 wt.%, particularly preferably 3-25 wt.%, extraordinarily preferably 4-15 wt.%, further extraordinarily preferably 5-10 wt.%, further extraordinarily preferably 6-7 wt.%, based on the weight of the agent.

8. Agent according to one of claims 1-7, characterized in that cysteine ​​is contained in an amount of 0.1-5.0 wt.%, preferably 0.5-3.0 wt.%, particularly preferably 0.8-2.0 wt.%, extraordinarily preferably 1.0-1.5 wt.%, based on the weight of the agent.

9. Agent according to one of claims 1 - 8, characterized in that isatin is contained in an amount of 0.01 - 1.0 wt.%, preferably 0.05 - 0.5 wt.%, particularly preferably 0.08 - 0.3 wt.%, extraordinarily preferably 0.1 - 0.2 wt.%, based on the weight of the agent.

10. Agent according to one of claims 1-9, characterized in that water is contained in an amount of 19.9-95.0 wt.%, preferably 30.0-90.0 wt.%, particularly preferably 50.0-88.0 wt.%, extraordinarily preferably 60.0-85.0 wt.%, based on the weight of the agent.

11. Agent according to one of claims 1-10, characterized in that it does not contain hydrogen peroxide.

12. Agent according to one of claims 1-11, characterized in that the molar ratio of cysteine ​​to isatin is 1.5 to 20, preferably 3 to 18, particularly preferably 5 to 15, extraordinarily preferably 10 to 13.

13. A process for the non-oxidative coloring of keratin fibers, in particular human hair, comprising the following process steps in the given order: a) providing an aqueous coloring composition (A) which contains at least one indigo or indirubin-producing plant powder i), further cysteine ​​and isatin and has a pH of 2.0 to less than 10.0, preferably from 4.0 to 9.0, particularly preferably from 5.0 to 8.0, extremely preferably from 6.7 to less than 7.5, in each case measured at 20°C, b) applying the aqueous dyeing composition (A) to the keratin fibers, c) leaving to act for a time of 30 seconds to 60 minutes, preferably 5 to 45 minutes, particularly preferably 15 to 30 minutes, d) rinsing the keratin fibers with water, e) optionally drying the keratin fibers, wherein no hydrogen peroxide is used in the process.

14. Dyeing process according to claim 13, characterized in that the dyeing composition (A) is allowed to act with the addition of heat, preferably at a temperature of 25 - 60 °C, particularly preferably at a temperature of 30 - 50 °C, extremely preferably at a temperature of 35 - 40 °C.

15. Dyeing process according to one of claims 13 or 14, characterized in that the dyeing composition (A) is an agent according to one of claims 2-12.

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