EP4182034A1

EP4182034A1 - Products for treating keratinous fibers, containing complexing agent and amino acid and/or protein hydrolysate

Info

Publication number: EP4182034A1
Application number: EP21728233.4A
Authority: EP
Inventors: Konstantin Goutsis; Daniela Kessler-Becker
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 2020-07-20
Filing date: 2021-05-26
Publication date: 2023-05-24
Also published as: WO2022017665A1; DE102020209041A1

Abstract

The invention relates to products for treating keratinous fibers, in particular human hair, containing (a) at least one complexing agent of the general formula (I), (I) wherein n is an integer from 1 to 6, X1, X2 independently of each other represent a hydrogen atom or an equivalent of an alkali ion, alkaline earth ion or metal ion, preferably sodium, potassium, ½ magnesium, ½ calcium, ½ zinc, or an ammonium ion (NH₄+), and (b) at least one amino acid and/or a protein hydrolysate.

Description

"Means for the treatment of keratin fibers with complexing agent and amino acid and/or protein hydrolyzate"

The present invention is in the field of cosmetics and relates to agents for the treatment of keratin fibers, in particular human hair, which are particularly suitable for lightening or bleaching the keratin fibers.

Changing the shape and color of the hair is an important area of modern cosmetics. In addition to coloring, many consumers want their hair to be lightened or bleached, since a blonde hair color is considered attractive and desirable from a fashion point of view . Various bleaching agents with different bleaching performance are available on the market for this purpose.

The oxidizing agents contained in bleaching agents are able to lighten the hair fiber through the oxidative destruction of the hair's own pigment, melanin. For a moderate bleaching effect, the use of hydrogen peroxide - optionally with the use of ammonia or other alkalizing agents - as the oxidizing agent alone is sufficient. A mixture of hydrogen peroxide and peroxodisulfate salts and/or peroxomonosulfate salts is usually used to achieve a stronger bleaching effect.

If the original hair is dark, longer application times and/or repeated bleaching processes are usually necessary in order to lighten the hair over several shades. However, this is also accompanied by greater damage to the hair, since not only the dyes of the hair but also the other structural components of the hair are damaged by oxidation. Depending on the extent of the damage, it ranges from rough, brittle hair that is difficult to comb through to reduced resistance and tear resistance of the hair to hair breakage.

The use of complexing agents in the case of oxidative color changes in keratin fibers is known in the prior art. The complexing agents should, among other things, prevent the decomposition of the hydrogen peroxide by metal ions accumulated in the hair fibers.

Thus, EP 1714634 A1 describes a hair treatment kit for coloring human hair, comprising a first compartment containing a complexing agent and a second compartment containing agents for coloring. By using a complexing agent unwanted reactions on and with hair, which lead to unwanted heating, are prevented.

In many bleaching products on the market, HEDP (etidronic acid) or its salts or EDTA (ethylenediamine tetraacetate) or its salts are used as complexing agents. Both HEDP and EDTA stabilize hydrogen peroxide in an effective manner and complex existing metal ions so efficiently that an undesirable temperature increase occurring during use is almost completely avoided. However, the major disadvantage of HEDP and EDTA is their poor biodegradability. Particularly in recent times, users have been paying increasing attention to the ecological profile of the cosmetic products they use. The user prefers cosmetics that are as sustainable as possible with biodegradable ingredients.

The use of substances of natural origin as complexing agents is also already known in the literature. For example, EP 1462090 A1 describes agents for bleaching, coloring or shaping hair, which contain the combination of at least one oxidizing agent and at least one polyhydroxycarboxylic acid. Even if the polyhydroxycarboxylic acids of EP 1462090 A1 are readily biodegradable, the performance properties of the agents described in this document are still in need of improvement, and the bleaching performance in particular cannot yet be regarded as optimal.

It was the object of the present invention to find bleaching agents with biodegradable complexing agents which, with regard to their bleaching performance, are superior to the bleaching or lightening agents known from the prior art. Furthermore, the bleaching agents should have a sufficiently high stability and should not heat up too much even when used on hair with a higher metal or heavy metal content. In addition, hair damage should be reduced when using the complexing agents in lightening or bleaching agents.

Surprisingly, it has now turned out that this problem can be solved in full if an agent is used on the keratin fibers which, in addition to at least one special complexing agent (a) of the formula (I), also contains at least one amino acid and/or a protein hydrolyzate ( b) contains.

A first subject matter of the present invention is a composition for treating keratin fibers, in particular human hair

(a) at least one complexing agent of the general formula (I), x _! OOC - (CHOH)n - COOX ₂

(l) where n is an integer from 1 to 6, and

X1, X2 independently represent a hydrogen atom or an equivalent of an alkali, alkaline earth or metal ion, preferably sodium, potassium, 1 magnesium, 14 calcium, 14 zinc, or an ammonium ion (NhV), and (b) at least one Amino acid and/or a protein hydrolyzate.

keratin fibers

Keratin fibers or keratin fibers are to be understood as meaning fur, wool, feathers and, in particular, human hair. Although the agents are primarily suitable for treating or lightening keratin fibers, in principle there is nothing to prevent them from being used in other areas as well.

Means for treating keratin fibers

The term "treatment of keratin fibers" used according to the invention includes in principle every possible form of treatment, i.e. shampoos, conditioners and styling agents as well as colorants, bleaching agents and permanent wave agents. However, the combination of ingredients (a) and (b) shows particularly good suitability in agents for lightening the keratin fibers. A lightening is to be understood as meaning any form of color change in the fibers in which the keratin fibers have a lighter color compared to the color present before the application of the agent. In particular, the color changes covered by the terms lightening, bleaching and bleaching are included. The hair is lightened by at least one oxidizing agent present in the composition. In addition to the oxidizing agent or agents, the agents according to the invention can also contain coloring components, such as oxidation dye precursors and/or substantive dyes, for the purpose of shading. The coloring components can be used to slightly modify the color of the resulting coloring. However, these coloring components are preferably present in the agent in such small amounts that the color impression of the keratin fibers treated with the agent is nevertheless lighter than their original color. Corresponding coloring techniques can be referred to as coloring bleaching or as nuanced bleaching.

The agent contains the components (a) and (b) essential to the invention, preferably in a cosmetic carrier. For example, a suitable aqueous, alcoholic or aqueous-alcoholic carrier can be used as a cosmetic carrier for the agent. For the purpose of hair coloring, such carriers are, for example, creams, emulsions, gels, pastes or foaming solutions containing surfactants, such as shampoos, foam aerosols, foam formulations or other preparations which are suitable for use on the hair. Within the scope of this embodiment, a composition for lightening keratinic fibers, in particular human hair, contained in a cosmetic carrier is therefore particularly preferred

(a) at least one complexing agent of the general formula (I),

Xi OOC — (CHOH) n — COOX ₂

(l) where n is an integer from 1 to 6, and

X1, X2 independently represent a hydrogen atom or an equivalent of an alkali, alkaline earth or metal ion, preferably sodium, potassium, magnesium, calcium, zinc, or an ammonium ion (NH ₄ ⁺ ), and

(b) at least one amino acid and/or a protein hydrolyzate.

This agent according to the invention is a ready-to-use agent that can be applied in this form to the keratin fibers for the purpose of bleaching or lightening.

complexing agent (a)

As the first ingredient essential to the invention, the agent according to the invention contains at least one complexing agent (a) of the general formula (I),

Xi OOC — (CHOH) n — COOX ₂

(l) where n is an integer from 1 to 6, and

X1, X2 independently represent a hydrogen atom or an equivalent of an alkali, alkaline earth or metal ion, preferably sodium, potassium, magnesium, calcium, zinc, or an ammonium ion (NH ₄ ⁺ ).

The complexing agents of the formula (I) are described as being biodegradable and therefore represent an ecologically advantageous replacement for HEDP and EDTA in bleaching or lightening agents, the bleaching performance could also be greatly improved. The complexing agents of the formula (I) are alkane diacids which—depending on the number of structural units (CHOH) present in the middle part of the molecule—are substituted with one to six hydroxy groups. The number of structural units (CHOH) is given by the index number n, which stands for an integer from 1 to 6.

In principle, n can stand for the numbers 1, 2, 3, 4, 5 or 6. However, a particularly strong improvement in bleaching performance was observed when n is an integer from 2 to 5, preferably an integer from 3 to 4 and very particularly preferably the number 4.

In a particularly preferred embodiment, an agent according to the invention is characterized in that it contains at least one complexing agent (a) of the general formula (I), where n is an integer from 2 to 5, preferably an integer from 3 to 4 and very particularly preferably the number 4.

The radicals X1 and X2 independently represent a hydrogen atom or an equivalent of an alkali metal, alkaline earth metal or metal ion, preferably sodium, potassium, 1 magnesium, 14 calcium, 14 zinc, or an ammonium ion (NH ₄ ⁺ ).

When X1 and X2 are both hydrogen, the compound of formula (I) is in the form of its free diacid HOOC-(CHOH) _n -COOH.

When X1 and X2 are both sodium ions, the compound of formula (I) is in the form of its sodium salt, NaOOC-(CHOH) _n -COONa.

When X1 and X2 both represent a potassium ion, the compound of formula (I) is in the form of its potassium salt KOOC-(CHOH) _n -COOK.

When X1 and X2 are each one equivalent of a calcium salt, the compound of formula (I) is in the form of its calcium salt Ca[OOC-(CHOH) _n -COO].

When X1 and X2 are each one equivalent of a magnesium salt, the compound of formula (I) is in the form of its magnesium salt Mg[OOC-(CHOH) _n -COO].

When both X1 and X2 are an ammonium ion, the compound of formula (I) is in the form of its ammonium salt, (NH4)OOC-(CHOH) _n -COO(NH4).

Furthermore, it is also possible for the radicals X1 and X2 to stand for different radicals from the group consisting of a hydrogen atom or the corresponding equivalent of an alkali metal, alkaline earth metal or metal ion. The complexing agents of the formula (I) can have one or more stereogenic centers. Both the D forms of the compounds and their L forms and mixtures thereof are encompassed by the present compound. The meso forms are also covered by the invention.

In bleaching experiments, particularly good results were also achieved when at least one complexing agent (a) of the formula (I) selected from the group consisting of galactaric acid, glucaric acid, mannaric acid, altaric acid, idaric acid, talaric acid, gularic acid and allaric acid was used in the agent according to the invention and their salts.

In a particularly preferred embodiment, an agent according to the invention is characterized in that it contains at least one complexing agent (a) of the general formula (I), which is selected from the group consisting of galactaric acid, glucaric acid, mannoic acid, altraric acid, idaric acid, talaric acid, gularic acid, allaric acid and its salts.

The above compounds belong to the group of aldar acids, i.e. acids derived from sugars that carry two carboxy groups.

Alternatively, galactaric acid is also referred to as mucic acid or mucic acid and is one of the polyhydroxy dicarboxylic acids. Other alternative names for galactaric acid are (2R,3S,4R,5S)-2,3,4,5-tetrahydroxyadipic acid, (2R,3S,4R,5S)-2,3,4,5-tetrahydroxyhexane-1,6-dioic acid , D-galactaric acid (IUPAC). It belongs to the sugar dicarboxylic acids (aldar acids). It shows no optical activity and has the CAS number 526-99-8.

Galactaric acid can be purchased commercially, for example, in the form of the raw material Muciliance® Fruit; this raw material is galactaric acid or mucaric acid in powder form and is sold by the Givaudan company. Furthermore, galactaric acid can also be purchased commercially from fine chemical suppliers such as Sigma Aldrich or Merck.

Alternatively, glucaric acid may also be referred to as D-glucaric acid or and is a polyhydroxy dicarboxylic acid. Other alternative names for glucaric acid are (2S,3S,4S,5R)-2,3,4,5-tetrahydroxyhexane-1,6-dioic acid and (2S,3S,4S,5R)-2,3,4,5-tetrahydroxyadipic acid . Glucaric acid has the CAS number 87-73-0.

Alternatively, mannonic acid can also be referred to as D-mannonic acid or as (2S,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexane-1,6-dioic acid.

Very particularly good results were obtained when using galactaric acid as complexing agent (a). Within the scope of an explicitly very particularly preferred embodiment, an agent according to the invention is characterized in that it contains (a) galactaric acid.

By using the complexing agent or complexing agents (a) in certain ranges of amounts, the performance properties of the agents according to the invention can be further optimized. If the combination of (a) and (b) is used in a composition for lightening keratin fibers, the lightening performance can be further improved by choosing suitable ranges of amounts. It is therefore particularly preferred if the agent - based on its total weight - contains one or more complexing agents (a) of the formula (I) in a total amount of from 0.01 to 10.0% by weight, preferably from 0.05 to 5 0.0% by weight, more preferably from 0.1 to 2.0% by weight and most preferably from 0.15 to 0.5% by weight.

In a particularly preferred embodiment, a composition according to the invention is characterized in that it contains one or more complexing agents (a) of the formula (I) in a total amount of from 0.01 to 10.0% by weight, based on the total weight of the composition. , preferably from 0.05 to 5.0% by weight, more preferably from 0.1 to 2.0% by weight and very particularly preferably from 0.15 to 0.5% by weight.

Amino acid and/or protein hydrolyzate (bl

The middle according to the invention contains at least one amino acid and/or a protein hydrolyzate (b) as the second essential component of the invention.

An amino acid means a chemical compound with an amino group and a carboxylic acid group. The class of amino acids includes organic compounds that contain at least one amino group (-NH2 or substituted -NR2) and one carboxy group (-COOH) as functional groups, i.e. have structural features of amines and carboxylic acids. Chemically, they can be distinguished according to the position of their amino group in relation to the carboxy group - _{if the amino group on the C a} atom is immediately adjacent to the terminal carboxy group, this is called the a position and is referred to as a-amino acids. Preference is given to using carboxylic acids having a total number of carbon atoms from C2-C20, more preferably from C2-C15, particularly preferably from C2-C10.

In a further embodiment, an agent according to the invention is characterized in that it contains at least one amino acid (b) from the group consisting of lysine, arginine, histidine, asparagine, glutamine, cysteine, methionine, tryptophan, serine, alanine, aspartic acid, glutamic acid, glycine, Contains isoleucine, leucine, phenylalanine, proline, threonine, tyrosine and valine.

Preferred amino acids are selected from lysine, arginine, histidine, asparagine, glutamine, cysteine, methionine, tryptophan, serine, alanine, aspartic acid, glutamic acid, glycine, isoleucine, leucine, phenylalanine, proline, threonine, tyrosine and valine and mixtures of these amino acids.

Particularly good results were obtained when arginine or lysine was used as the amino acid.

Likewise, particularly good values with regard to the lightening performance and the heat development when using the bleaching agent could be found when the combination of arginine and lysine was contained in the agent according to the invention.

Bleaching agents containing valine, glycine, serine and/or glutamic acid as amino acids also showed improved bleaching performance.

Chiral amino acids have a sterogenic center and can exist in mirror-image forms. For example, arginine occurs in the form of L-arginine and D-arginine. Both the L-form of an amino acid and its D-form and mixtures thereof are encompassed by the present invention. Accordingly, within the scope of the present invention, both possible enantiomers can be used equally as a specific compound or mixtures thereof, in particular as racemates. However, it is particularly advantageous to use the naturally occurring isomer form, usually in the L configuration.

In order to achieve the best possible results, in particular good lightening results, the amino acid(s) (b) are preferably used in specific quantity ranges. It has proven to be particularly advantageous if the agent - based on its total weight - contains one or more amino acids (b) in a total amount of 0.1 to 10.0% by weight, preferably 0.2 to 5.0% by weight. -% contains, more preferably from 0.3 to 2.5% by weight and very particularly preferably from 0.4 to 1.0% by weight.

Within the scope of a further particularly preferred embodiment, an agent according to the invention is characterized in that it contains one or more amino acids (b) in a total amount of from 0.1 to 10.0% by weight, preferably 0, based on the total weight of the agent. 2 to 5.0% by weight, more preferably from 0.3 to 2.5% by weight and very particularly preferably from 0.4 to 1.0% by weight.

Furthermore, good results can be obtained if, on average, at least one protein hydrolyzate was used in addition to or instead of the amino acid.

According to the invention, protein hydrolyzates are degradation products of proteins which are produced by acidic, basic or enzymatic reactions. Due to the manufacturing process, protein hydrolysates have a distribution of molecular weights. To those according to the invention Protein hydrolyzates also include oligopeptides, since these can also be produced from proteins by appropriate reactions. According to the invention, individual amino acids which are present as discrete individual compounds are not among the protein hydrolyzates in the context of this invention. According to the invention, protein hydrolyzates of both plant and animal or marine or synthetic origin can be used.

For the purposes of the present invention, protein hydrolyzates are understood to mean at most oligomeric compounds composed of a maximum of 10 amino acids.

Animal protein hydrolysates are, for example, elastin, collagen, keratin, silk and milk protein hydrolysates, which can also be present in the form of salts. Such products are sold, for example, under the trademarks Dehylan ^® (Cognis), Promois ^® (Interorgana), Collapuron ^® (Cognis), Nutrilan ^® (Cognis), Gelita-Sol ^® (Deutsche Gelatine Fabriken Stoess & Co), Lexein ^® (Index), ProSina ^® (Croda) and kerasol tm ^® (Croda) sold.

Furthermore, vegetable protein hydrolysates which are preferred according to the invention are, for example, soybean, almond, pea, moringa, potato and wheat protein hydrolysates. Such products are, for example, under the trademarks Gluadin ^® (Cognis), diamine ^® (Diamalt) ^® (Index) Hydrosoy ^® (Croda), hydro Lupine ^® (Croda), hydro Sesame ^® (Croda), Hydro tritium ^® (Croda), Crotein ^® (Croda) and Puricare ^® LS 9658 from Laboratoires Serobiologiques.

Further protein hydrolyzates preferred according to the invention are of maritime origin. These include, for example, collagen hydrolysates from fish or algae and protein hydrolysates from mussels or pearl hydrolysates. Examples of pearl extracts according to the invention are the commercial products Pearl Protein Extract BG ^® or Crodarom ^® Pearl.

Furthermore, cationized protein hydrolyzates are among the protein hydrolyzates, the underlying protein hydrolyzate from animals, for example from collagen, milk or keratin, from plants, for example from wheat, corn, rice, potatoes, soybeans or almonds, from marine life forms, for example from fish collagen or algae, or biotechnologically obtained protein hydrolyzates. As typical examples of the inventive cationic protein hydrolysates and derivatives are under the INCI - ^th names in the "International Cosmetic Ingredient Dictionary and Handbook" (seventh edition 1997, The Cosmetic, Toiletry, and Fragrance Association 1101 17 Street, NW, Suite 300 , Washington, DC 20036-4702) and commercially available products.

Good results were observed when preparation (B) contained at least one protein hydrolyzate selected from elastin hydrolyzates, collagen hydrolyzates, of keratin, silk, milk protein, as well as soy, almond, pea, moringa, potato and wheat protein hydrolysates.

In a further particularly preferred embodiment, an agent according to the invention is characterized in that it contains at least one protein hydrolyzate (b) selected from the group consisting of protein hydrolyzates of elastin, collagen, keratin, silk, milk protein, soybean, Almond, Pea, Moringa, Potato and Wheat Protein Hydrolysates.

In order to achieve the best possible results, in particular good lightening results, the protein hydrolyzates (b) are preferably used in specific quantity ranges. It has turned out to be particularly advantageous if the agent contains one or more protein hydrolyzates (c) in a total amount of 0.1 to 10.0% by weight, preferably 0.2 to 5.0% by weight preferably from 0.3 to 2.5% by weight and very particularly preferably from 0.4 to 1.0% by weight.

In a further particularly preferred embodiment, an agent according to the invention is characterized in that it - based on its total weight - one or more protein hydrolyzates (c) in a total amount of 0.1 to 10.0 wt .-%, preferably 0.2 to 5.0% by weight, more preferably from 0.3 to 2.5% by weight and very particularly preferably from 0.4 to 1.0% by weight.

Protein hydrolyzates according to the invention are also oligopeptides. Oligopeptides can be preferred in the hair treatment agents according to the invention because of their defined amino acid sequence.

An oligopeptide having at least one amino acid sequence Glu-Glu-Glu has, where the amino group can be free or protonated and the carboxy groups can be free or deprotonated, can be particularly preferred according to the invention. In this, as in all the following formulas, the bracketed hydrogen atom of the amino group as well as the bracketed hydroxy group of the acid function means that the relevant groups can be present as such (then it is an oligopeptide with the relevant number of amino acids as in the above formula, or that the amino acid sequence in an oligopeptide is present which comprises further amino acids - depending on where the further amino acid(s) is/are bound, the components in brackets of the above formula are replaced by the further amino acid residue(s).

For the purposes of the present application, oligopeptides are condensation products of amino acids linked by peptide bonds in the manner of acid amides, which comprise at least 3 and at most 25 amino acids. In hair treatment compositions preferred according to the invention, the oligopeptide comprises 5 to 15 amino acids, preferably 6 to 13 amino acids, particularly preferably 7 to 12 amino acids and in particular 8, 9 or 10 amino acids. Depending on whether other amino acids are bound to the Glu-Glu-Glu sequence and depending on the type of these amino acids, the molar mass of the oligopeptide contained in the agents according to the invention can vary. Hair treatment agents preferred according to the invention are characterized in that the oligopeptide has a molar mass of 650 to 3000 Da, preferably 750 to 2500 Da, particularly preferably 850 to 2000 Da and in particular 1000 to 1600 Da. As can be seen from the preferred number of amino acids in the oligopeptides and the preferred molar mass range, oligopeptides are preferably used which do not consist solely of the three glutamic acids but also have other amino acids bound to this sequence. These further amino acids are preferably selected from certain amino acids, while certain other representatives are less preferred according to the invention. A particularly preferred oligopeptide additionally contains tyrosine, which is preferably linked to the Glu-Glu-Glu sequence via its acid function. Hair treatment agents which are preferred according to the invention are therefore characterized in that the oligopeptide contained in them contains at least one amino acid sequence Tyr-Glu-Glu-Glu has, wherein the amino group can be free or protonated and the carboxy groups can be free or deprotonated.

Another particularly preferred oligopeptide additionally contains isoleucine, which is preferably bound to the Glu-Glu-Glu sequence via its amino function. Hair treatment agents which are preferred according to the invention are therefore characterized in that the oligopeptide contained in them has at least one amino acid sequence Glu-Glu-Glu-Ile has, wherein the amino group can be free or protonated and the carboxy groups can be free or deprotonated.

According to the invention, preference is given to oligopeptides which contain both of the aforementioned amino acids (tyrosine and isoleucine). Hair treatment agents according to the invention in which the oligopeptide contained in them has at least one amino acid sequence Tyr-Glu-Glu-Glu-Ile has, wherein the amino group can be free or protonated and the carboxy groups can be free or deprotonated.

Further preferred oligopeptides additionally contain arginine, which is preferably present bound to isoleucine

Even more preferred oligopeptides additionally contain valine, which is preferably bound to the arginine. Hair treatment agents that are further preferred according to the invention are therefore characterized in that the oligopeptide contained in them contains at least one amino acid sequence Tyr-Glu-Glu-Glu-Glu-Ile-Arg-Val has, wherein the amino

Groups can be free or protonated and the carboxy groups can be free or deprotonated. Even more preferred oligopeptides additionally contain leucine, which is preferably bound to the valine. Hair treatment agents which are further preferred according to the invention are characterized in that the oligopeptide contained in them contains at least one amino acid sequence Tyr- Glu-Glu-Glu-Ile-Arg-Val-Leu where the amino groups can be free or protonated and the carboxy groups can be free or deprotonated.

Particularly preferred oligopeptides additionally contain leucine, which is preferably present bound to the tyrosine. Hair treatment agents which are further preferred according to the invention are characterized in that the oligopeptide contained in them contains at least one amino acid sequence Leu-Tyr-Glu-Glu-Glu-Ile-Arg-Val-Leu has, wherein the amino groups can be free or protonated and the carboxy groups can be free or deprotonated.

Weight ratio (aV(b ^' )

The work leading to this invention has shown that there appears to be a synergistic effect between components (a) and (b). In particular, when both components (a) and (b) are used in an agent for oxidative color change, it has been shown that (a) and (b) together improve the lightening performance particularly greatly if they are present in a specific weight ratio to one another in the funds are available.

For this reason, it has been found to be particularly preferred if the weight ratio of all complexing agents (a) of the formula (I) contained in the agent to all compounds from the group of amino acids and protein hydrolyzates (b) contained in the agent, i.e. the Weight ratio (a)/(b), at a value from 0.1 to 10, preferably from 0.2 to 5, more preferably from 0.25 to 4.0, and very particularly preferably from 0.3 to 1.0 located.

In a further preferred embodiment, a composition according to the invention is characterized in that the weight ratio of all complexing agents (a) contained in the composition to all compounds from the group of amino acids and protein hydrolyzates (b) contained in the composition, ie the weight ratio (a)/(b ), at a value from 0.1 to 10, preferably from 0.2 to 5, more preferably from 0.25 to 4.0, and very particularly preferably from 0.3 to 1.0.

In a very preferred embodiment, a composition according to the invention is characterized in that the weight ratio of all complexing agents (a) contained in the composition to all compounds from the group of amino acids (b) contained in the composition, ie the weight ratio (a)/(b), is from 0.1 to 10, preferably from 0.2 to 5, more preferably from 0.25 to 4.0, and very particularly preferably from 0.3 to 1.0.

Composition for lightening keratin fibers with oxidizing agent (c)

As already described above, the combination of ingredients (a) and (b) shows its potential particularly when used in agents for lightening or bleaching hair.

To achieve moderate whitening effects, hydrogen peroxide is the oxidizing agent of choice. As bleaching and bleaching agents, preferred agents are further characterized in that they contain hydrogen peroxide and/or one of its solid adducts with organic or inorganic compounds. However, if stronger lightening or bleaching is desired, hydrogen peroxide is used together with stronger oxidizing agents such as persulphates (sodium persulphate, potassium persulphate or ammonium persulphate).

In a particularly preferred embodiment, an agent according to the invention is characterized in that it

(c) contains at least one oxidizing agent from the group consisting of hydrogen peroxide, ammonium peroxodisulphate, potassium peroxodisulphate and sodium peroxodisulphate.

Within the scope of this embodiment, a composition for lightening keratinic fibers, in particular human hair, contained in a cosmetic carrier is therefore particularly preferred

(a) at least one complexing agent of the general formula (I),

X, OOC - (CHOH) n - COOX ₂

(I) where n is an integer from 1 to 6, and

X1, X2 independently represent a hydrogen atom or an equivalent of an alkali, alkaline earth or metal ion, preferably sodium, potassium, 1 magnesium, 14 calcium, 14 zinc, or an ammonium ion (NH ₄ ⁺ ), and

(b) at least one amino acid and/or a protein hydrolyzate, and

(c) at least one oxidizing agent from the group consisting of hydrogen peroxide, ammonium peroxodisulphate, potassium peroxodisulphate and sodium peroxodisulphate.

Ammonium peroxodisulfate, which can alternatively also be referred to as ammonium persulfate, is understood as meaning the persulfate with the empirical formula (NH ₄ ) ₂ S ₂ O 8 .

Potassium peroxodisulfate, which can alternatively also be referred to as potassium persulfate, means the persulfate with the molecular formula K2S2O8.

Sodium peroxodisulfate, which can alternatively also be referred to as sodium persulfate, is understood as meaning the persulfate with the molecular formula Na ₂ S ₂ Os.

In a particularly preferred embodiment, an agent according to the invention is characterized in that it contains (c1) hydrogen peroxide and

(c2) at least one persulphate from the group consisting of ammonium persulphate, potassium persulphate and sodium persulphate.

In another preferred embodiment, hydrogen peroxide itself is used as an aqueous solution. The concentration of a hydrogen peroxide solution in the agent according to the invention is determined on the one hand by the legal requirements and on the other hand by the desired effect; preferably 3 to 12% by weight solutions in water are used. Agents preferred according to the invention of the first subject matter of the invention are characterized in that, based on the total weight of the agent, they contain (a) 0.1 to 12.0% by weight, preferably 0.5 to 10.5% by weight, more preferably 1 0 to 8.5% by weight, more preferably from 1.5 to 7.0% by weight and very particularly preferably 1.5 to 6.0% by weight, of hydrogen peroxide.

In a particularly preferred embodiment, a composition according to the invention is characterized in that it contains (c) 0.1 to 12.0% by weight, preferably 0.5 to 10.5% by weight, based on the total weight of the composition preferably 1.0 to 8.5% by weight, even more preferably from 1.5 to 7.0% by weight and very particularly preferably 1.5 to 6.0% by weight hydrogen peroxide.

The persulfate or persulfates are also preferably used in specific quantity ranges in the agent according to the invention. It turned out to be preferable if the means - based on the total weight of the agent - (c) one or more persulfates from the group consisting of ammonium peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate in a total amount of 2.0 to 40.0% by weight, preferably 4.0 to 30.0% by weight. -%, more preferably from 6.0 to 20.0% by weight and most preferably from 8.0 to 15.0% by weight.

In a particularly preferred embodiment, an agent according to the invention is characterized in that - based on the total weight of the agent - (c) one or more persulfates from the group consisting of ammonium peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate in a total amount of 2.0 to 40.0 % by weight, preferably from 4.0 to 30.0% by weight, more preferably from 6.0 to 20.0% by weight and very particularly from 8.0 to 15.0% by weight.

Within the scope of a further embodiment, a composition for lightening keratinic fibers, in particular human hair, contained in a cosmetic carrier is therefore particularly preferred

(a) at least one complexing agent of the general formula (I),

Xi OOC — (CHOH) n — COOX ₂

(l) where n is an integer from 1 to 6, and

(b) at least one amino acid and/or a protein hydrolyzate, and (c1) hydrogen peroxide and

alkalizing agents

As already described above, the agent according to the first subject matter of the invention is a ready-to-use agent for lightening or bleaching keratin fibers. In order to achieve an adequate bleaching effect, such agents are usually made highly alkaline, with the pH preferably being between 9 and 10.5. Such high pH values are necessary in order to ensure that the outer cuticle layer (cuticle) opens and thus allows penetration of the active species (hydrogen peroxide and persulphates) into the hair. For this reason it has turned out to be very particularly preferred if the agent according to the invention additionally contains at least one alkalizing agent.

Within the scope of a further preferred embodiment, an agent according to the invention is characterized in that it contains at least one alkalizing agent.

Preferred alkalizing agents are, for example, ammonia, alkanolamines, basic amino acids, and inorganic alkalizing agents such as (earth) alkali metal hydroxides (earth) - alkali metal metasilicates (earth) alkali metal silicates (earth) alkali metal phosphates and (earth) - alkali metal hydrogen phosphates. Lithium, sodium and/or potassium preferably serve as metal ions. Preferred alkalizing agents are (earth) alkali metal metasilicates and (earth) alkali metal silicates.

Suitable inorganic alkalizing agents are preferably selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, sodium phosphate, potassium phosphate, sodium silicate, potassium silicate, magnesium silicate, sodium carbonate and potassium carbonate. Sodium hydroxide and/or potassium hydroxide are particularly preferred.

Alkanolamines used as alkalizing agents are preferably selected from primary, secondary or tertiary amines with a C2-C6-alkyl skeleton which carries at least one hydroxyl group. Particularly preferred alkanolamines are selected from the group formed from 2-aminoethan-1-ol (monoethanolamine), 3-aminopropan-1-ol, 4-aminobutan-1-ol, 5-aminopentan-1-ol, 1 -aminopropan-2-ol (monoisopropanolamine), 1-aminobutan-2-ol, 1-aminopentan-2-ol, 1-aminopentan-3-ol, 1-aminopentan-4-ol, 2-amino-2-methyl- propanol, 2-amino-2-methylbutanol, 3-amino-2-methylpropan-1-ol, 1-amino-2-methylpropan-2-ol, 3-aminopropan-1,2-diol, 2-amino-2- methylpropane-1,3-diol, 2-amino-2-ethyl-1,3-propanediol, N,N-dimethylethanolamine, methylglucamine, triethanolamine, diethanolamine and triisopropanolamine. Particularly preferred alkanolamines are monoethanolamine, 2-amino-2-methylpropanol and triethanolamine.

Basic amino acids as alkalizing agents are preferably selected from the group consisting of L-arginine, D-arginine, D/L-arginine, L-lysine, D-lysine, D/L-lysine, L-ornithine, D-ornithine , D/L-ornithine, L-histidine, D-histidine and/or D/L-histidine. L-arginine, D-arginine and/or D/L-arginine are particularly preferably used as an alkalizing agent.

No HEDP or EDTA

The aim of the present application is in particular to dispense with the non-biodegradable complexing agents HEDP and EDTA. For this reason, the agents according to the invention preferably contain these two complexing agents in particularly small amounts. The agents are very particularly preferably free of these two substances. Most preferably, the agent is also essentially free of the salts of HEDP and EDTA. In a further preferred embodiment, an agent according to the invention is characterized in that - based on the total weight of the agent - the total content of the etidronic acid and the salts of etidronic acid contained in the agent is below 0.2% by weight, preferably below 0.1% by weight %, more preferably below 0.05% by weight and very particularly preferably below 0.001% by weight.

In a further preferred embodiment, an agent according to the invention is characterized in that - based on the total weight of the agent - the total content of the EDTA contained in the agent and the salts of EDTA is less than 0.2% by weight, preferably less than 0.1% by weight %, more preferably below 0.05% by weight and very particularly preferably below 0.001% by weight

Etidronic acid is alternatively also referred to as hydroxyethane-1,1-diphosphonic acid and has the CAS number 2809-21-4.

EDTA is alternatively referred to as ethylenediamine tetraacetate and has CAS numbers 6381-92-6 and 139-33-3 (anhydrous). other ingredients

In addition to the ingredients (a), (b) and (c) that are essential to the invention—and optionally the alkalizing agents—the agent according to the invention can also contain other active ingredients and auxiliaries as optional ingredients. These are described below.

The agents can also contain other active ingredients, auxiliaries and additives, such as solvents, fatty components such as Cs-Cso fatty alcohols, C8-C30 fatty acid triglycerides, C8-C30 fatty acid monoglycerides, C8-C30 fatty acid diglycerides and/or hydrocarbons; nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric and/or zwitterionic surfactants, polymers; structurants such as glucose, maleic acid and lactic acid, hair conditioning compounds such as phospholipids, e.g. lecithin and cephalins; perfume oils, dimethylisosorbide and cyclodextrins; fiber structure-improving active ingredients, in particular mono-, di- and oligosaccharides such as glucose, galactose, fructose, fructose and lactose; dyes for coloring the agent; anti-dandruff agents such as Piroctone Olamine, Zinc Omadine and Climbazole; amino acids and oligopeptides; Protein hydrolyzates based on animals and/or plants, and in the form of their fatty acid condensation products or optionally anionically or cationically modified derivatives; vegetable oils; 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, plant extracts; fats and waxes such as fatty alcohols, beeswax, montan wax and paraffins; Swelling and penetrating substances such as glycerol, 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; and propellants such as propane-butane mixtures, N2O, dimethyl ether, CO2 and air.

The person skilled in the art will select these further substances in accordance with the desired properties of the agents. With regard to other optional components and the amounts of these components used, express reference is made to the relevant handbooks known to those skilled in the art. The additional active ingredients and auxiliaries are preferably used in the preparations according to the invention in amounts of 0.0001 to 25% by weight, in particular 0.0005 to 15% by weight, based on the total weight of the respective composition.

Process Treatment of keratin fibers, preferably for lightening keratin fibers As already described above, the agent of the first subject matter of the invention is an agent for treating keratin fibers. The agent is very particularly preferably a lightening or bleaching agent. Bleaching agent is a ready-to-use agent.

Accordingly, the agents can be used in a method for treating, in particular for lightening, the keratin fibers.

A second subject of the present invention is a method for treating keratin fibers, in which an agent, as disclosed in detail in the description of the first subject of the invention, is applied to the keratin fibers and rinsed out again after an exposure time.

In a very particularly preferred embodiment, the method is characterized in that it is a method for lightening keratin fibers.

Oxidizing agents such as hydrogen oxide and persulfates are highly reactive compounds that have only limited stability, especially in an alkaline environment. For this reason, the ready-to-use bleaching agent is usually produced shortly before use by mixing two or more separately packaged preparations.

The oxidizing agent (a) and the alkalizing agent are usually made up separately from one another. Various types of packaging are now conceivable for the complexing agent (a) and the amino acid and/or a protein hydrolyzate (b). For example, complexing agent (a) and amino acid/protein hydrolyzate (b) can be formulated together with one or more persulfates and separately from the hydrogen peroxide. This embodiment is particularly preferred when only two different preparations are to be mixed together to produce the ready-to-use agent.

In a preferred embodiment, a method for lightening keratin fibers, characterized in that at least two separately packaged preparations (A) and (B) are mixed to form an application mixture, which is applied to the fibers and rinsed off again after an exposure time, wherein

- the preparation (A) contains hydrogen peroxide (c1), and

- the preparation (B) contains

- at least one complexing agent (a) of general formula (I), and

- at least one amino acid and/or a protein hydrolyzate (b), and

- at least one persulfate (c2) from the group consisting of ammonium peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate, the complexing agent (a) and the amino acid/protein hydrolyzate (b) having already been disclosed in detail in the description of the first subject of the invention.

The preparations (A) and (B) can be mixed either with each other or with other separately packaged preparations immediately before use to form an application mixture.

If three different preparations are to be mixed together to produce the ready-to-use agent, it may be preferable to provide the first oxidizing agent hydrogen peroxide separately in a first preparation (A), to provide the persulfates as the second oxidizing agent separately in a second preparation (B) and furthermore to provide a third preparation (C) which comprises complexing agent (a) and amino acid/protein hydrolyzate (b).

In a further preferred embodiment, a method for lightening keratinic fibers is characterized in that at least three separately packaged preparations (A) and (B) and (C) are mixed to form an application mixture, which is applied to the fibers and rinsed off again after an exposure time will, where

- the preparation (A) contains hydrogen peroxide (c1), and

- the preparation (B) contains at least one persulfate (c2) from the group consisting of ammonium peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate, and

- the preparation (C) contains at least one complexing agent (a) of the general formula (I) and contains at least one amino acid and/or a protein hydrolyzate (b), wherein the complexing agent (a) and the amino acid/protein hydrolyzate (b) have already been disclosed in detail in the description of the first subject of the invention.

The preparations (B) containing the persulfates are preferably in powder form. Powders made from solid components with different particle sizes can be used here. However, it can usually be preferred if the powders have a particle size which is as homogeneous as possible, in particular in order to facilitate uniform dispersion or dissolution of the powders in the preparations (B).

Furthermore, the preparations (B) can also contain the persulfates in a solid cosmetic carrier. A solid cosmetic carrier can contain salts of silicic acid, in particular salts of silicates and metasilicates with ammonium, alkali metals and alkaline earth metals. In particular metasilicates, which are characterized according to formula (Si0 ₂ ) n (M ₂ 0) _m , where M is an ammonium ion, an alkali metal or a half stoichiometry equivalent of an alkaline earth metal, by the ratio between n and m of <1 and as chain-like polymeric structures of the anion [SiC>3] ² can be used with preference. Sodium metasilicate of the formula [Na ₂ SiO 3 ]- is particularly preferred. Likewise preferred are those silicates which are formed from a silicate of the formula (Si0 ₂ )n(Na ₂ 0) _m (K ₂ 0) _P , where n is a positive rational number and m and p are independently positive rational numbers or 0, with the proviso that at least one of m or p is different from 0 and the ratio of n to the sum of m and p is between 2:1 and 4:1.

Furthermore, the solid preparations (B) can contain so-called flow aids, which are intended to prevent the powder components from clumping or caking. Such flow aids are preferably water-insoluble, hydrophobic or moisture-absorbing powders of kieselguhr, pyrogenic silica, calcium phosphate, calcium silicates, aluminum oxide, magnesium oxide, magnesium carbonate, zinc oxide, stearates, fatty amines and the like.

Finally, preparations (B) can additionally contain a dedusting agent, which prevents the formation of dust from the pulverulent components. In particular, inert oils can be used for this purpose. The solid cosmetic carriers preferably contain ester oils or mineral oils, preferably hydrocarbon oils, such as liquid paraffin oil, as dust-removing agents.

The ready-to-use agents are prepared immediately before use on the hair by mixing the two preparations (A) and (B) or by mixing the three preparations (A) and (B) and (C). In the case of ready-to-use agents that are mixed from more than two preparations to form a ready-to-use mixture, it may be irrelevant whether two preparations are first mixed together and then the third preparation is added and mixed in, or whether all preparations are combined together and then mixed. Mixing can be accomplished by stirring in a bowl or beaker, or by shaking in a sealable container.

The term "immediately" is to be understood as a period of a few seconds to an hour, preferably up to 30 minutes, in particular up to 15 minutes.

The preparations (A), (B) and optionally (C) are used in a method for lightening keratin fibers, in particular human hair, in which the agent is applied to the keratin-containing fibers for an exposure time of 10 to 60 minutes on the Leave the fiber and then rinse it out with water or wash it out with a shampoo.

The exposure time of the ready-to-use lightening agent is preferably 10 to 60 minutes, in particular 15 to 50 minutes, particularly preferably 20 to 45 minutes. While the agent is acting on the fiber, it can be advantageous to support the lightening process by applying little heat. The heat can be supplied by an external heat source, such as with the aid of a warm air blower, and also, particularly in the case of hair lightening on living subjects, by the subject's body temperature. With the latter option, the area to be lightened is usually covered with a hood. An exposure phase at room temperature is preferred. After the exposure time has ended, the remaining lightening preparation is rinsed out of the hair with water or a cleaning agent. In particular, commercial shampoo can be used as the cleaning agent, in which case the cleaning agent can be dispensed with and the rinsing process can be carried out with tap water if the lightening agent has a carrier with a high surfactant content.

The preferred embodiments of the agent described above also apply mutatis mutandis to the method.

Examples 1 . preparations

The following ready-to-use bleaching agents were produced (all data in % by weight unless otherwise stated).

Table 1: ready-to-use bleaching agents 1 to 8, with 0.2% by weight of galactaric acid

Table 2: ready-to-use bleaching agents 9 to 12, with 3.0% by weight of galactaric acid

2. Coloration

Hair tresses (Kerling, Euronaturhaar 4-0) were colorimetrically measured (Datacolor Spectraflash SF 450), preshampooed and dried.

The previously prepared, ready-to-use bleaching agents were applied to the strands of hair, left there for 45 minutes and then rinsed out again with water. The hair tresses were then measured colorimetrically again. Each formulation was colored on two tresses of hair and these were measured. The average value was calculated from the measured values.

The higher the AL value, the greater the lightening of the strands compared to untreated hair. The higher the DE value, the greater the color shift of the strands compared to untreated hair. The bleaching performance is the better, the higher the DE value and in particular the AL value.

Table 3: colorimetric measurement of bleaching agents 1 to 8, with 0.2% by weight of galactaric acid

UB = Kerling 4-0 strands of hair untreated

Table 4: colorimetric measurement of bleaching agents 9 to 12, with 3.0% by weight of galactaric acid in preparation (C)

UB = Kerling 4-0 strands of hair untreated

3. Measurement of the temperature profile during the brightening

Strands with a high metal content were used to measure the temperatures occurring during bleaching. To produce this hair, strands of hair were treated as follows: strands of hair (Kerling, European natural hair white, 6-0) were pre-shampooed and then pre-bleached once with a commercially available bleaching agent. The pre-bleaching was done to increase the copper uptake in the hair. The pre-bleached strand was doped with copper:

For this purpose, 1 g strand was dipped into 40 g of a copper solution (50 ppm copper in water, 16.8° dH) and left there for 1 minute. Then the tress was taken out of the solution, squeezed out slightly and dried at room temperature. This dipping process was repeated three times for each tress.

Thereafter, the copper content of each strand of hair was determined analytically. The determination was made after mineralization of the sample (one strand each) in the microwave digestion system HN03/HCL by atomic emission spectrometry (ICP-OES). The average was formed from 12 measurements. The average copper content of each strand of hair was 3900 mg/kg.

The previously prepared, ready-to-use bleaching agents 1 to 8 were applied to the hair treated in this way. The strands were fitted with a Pt100 sensor and wrapped in aluminum foil. The reaction temperature was measured and documented every minute.

Table 5: Temperature of the ready-to-use bleaching agent on the hair, at 0.2% by weight

galactaric acid

All temperature curves measured on the hair when bleaching agents 1 to 8 were used were classified as acceptable. Particularly advantageous temperature profiles, i.e. a particularly low generation of heat, were found when using example formulations 3, 4 and 5.

4. Formulation examples

4.1 . Bleaching agents which are produced by mixing three preparations (A), (Bf and (Q).

To produce the ready-to-use lightening or bleaching agent, 60 g of preparation (A) were mixed with 20 g of preparation (B) and 60 g each of preparations (C1) to (C10).

4.2. Bleaching agents which are produced by mixing two preparations (A) and CB).

A ready-to-use bleaching agent was produced by mixing preparation (A) with one of each of preparations (B1) to (B8).

4.3. Bleaching agents that are produced by mixing two preparations (AI and (Bl

A ready-to-use bleaching agent was produced by mixing preparation (A) with one of each of preparations (B1) to (B4).

4.4. Lightening colorants obtained by mixing two formulations (A) and (B).

Preparation (A) was mixed with preparation (B) in a ratio of 1:1 in each case.

Claims

patent claims

1. Means for the treatment of keratin fibers, in particular human hair containing

(a) at least one complexing agent of the general formula (I),

Xi OOC — (CHOH) n — COOX ₂

(l) where n is an integer from 1 to 6, and

(b) at least one amino acid and/or a protein hydrolyzate.

2. Composition according to claim 1, characterized in that it contains at least one complexing agent (a) of the general formula (I), where n is an integer from 2 to 5, preferably an integer from 3 to 4 and very particularly preferably stands for the number 4.

3. Agent according to one of Claims 1 to 2, characterized in that it contains at least one complexing agent (a) of the general formula (I) which is selected from the group consisting of galactaric acid, glucaric acid, mannoic acid, altraric acid, idaric acid, talaric acid and gularic acid , allaric acid and their salts.

4. Agent according to one of claims 1 to 3, characterized in that it - based on the total weight of the agent - one or more complexing agents (a) of the formula (I) in a total amount of 0.01 to 10.0 wt. %, preferably from 0.05 to 5.0% by weight, more preferably from 0.1 to 2.0% by weight and very particularly preferably from 0.15 to 0.5% by weight.

5. Agent according to one of Claims 1 to 4, characterized in that it contains at least one amino acid (b) from the group consisting of lysine, arginine, histidine, asparagine, glutamine, cysteine, methionine, tryptophan, serine, alanine, aspartic acid, glutamic acid, Contains glycine, isoleucine, leucine, phenylalanine, proline, threonine, tyrosine and valine.

6. Agent according to one of claims 1 to 5, characterized in that it - based on the total weight of the agent - one or more amino acids (b) in a total amount from 0.1 to 10.0% by weight, preferably from 0.2 to 5.0% by weight, more preferably from 0.3 to 2.5% by weight and very particularly preferably from 0.4 to 1.0% by weight.

7. Agent according to one of claims 1 to 6, characterized in that it contains at least one protein hydrolyzate (b) which is selected from the group consisting of protein hydrolyzates of elastin, collagen, keratin, silk, milk protein, soybean, Almond, Pea, Moringa, Potato and Wheat Protein Hydrolysates.

8. Composition according to one of claims 1 to 7, characterized in that it - based on its total weight - one or more protein hydrolyzates (c) in a total amount of 0.1 to 10.0 wt .-%, preferably 0.2 to 5.0% by weight, more preferably from 0.3 to 2.5% by weight and very particularly preferably from 0.4 to 1.0% by weight.

9. Agent according to one of Claims 1 to 8, characterized in that the weight ratio of all complexing agents (a) contained in the agent to all compounds from the group of amino acids and protein hydrolyzates (b) contained in the agent, ie the weight ratio (a)/ (b) has a value of from 0.1 to 10, preferably from 0.2 to 5, more preferably from 0.25 to 4.0, and very particularly preferably from 0.3 to 1.0.

10. Composition according to one of claims 1 to 9, characterized in that it

11. Agent according to one of Claims 1 to 10, characterized in that - based on the total weight of the agent - (c) 0.1 to 12.0% by weight, preferably 0.5 to 10.5% by weight , more preferably 1.0 to 8.5% by weight, even more preferably from 1.5 to 7.0% by weight and very particularly preferably 1.5 to 6.0% by weight hydrogen peroxide.

12. Agent according to one of claims 1 to 11, characterized in that - based on the total weight of the agent - (c) one or more persulfates from the group consisting of ammonium peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate in a total amount of 2.0 to 40, 0% by weight, preferably from 4.0 to 30.0% by weight, more preferably from 6.0 to 20.0% by weight and very particularly from 8.0 to 15.0% by weight .

13. A method for treating keratin fibers, wherein an agent according to any one of claims 1 to 12 is applied to the keratin fibers and rinsed out again after a contact time.

14. The method according to claim 13, characterized in that it is a method for lightening keratin fibers.