AU2005251434A1 - Mild bleaching agent with an improved bleaching capacity - Google Patents

Description

IN THE MATTER OF an Australian Application corresponding to PCT Application PCT/EP2005/005231 RWS Group Ltd, of Europa House, Marsham Way, Gerrards Cross, Buckinghamshire, England, hereby solemnly and sincerely declares that, to the best of its knowledge and belief, the following document, prepared by one of its translators competent in the art and conversant with the English and German languages, is a true and correct translation of the PCT Application filed under No. PCT/EP2005/00523 1. Date: 14 November 2006 N. T. SIMPKIN Acting Deputy Managing Director For and on behalf of RWS Group Ltd H0608OPCT "Mild bleaching agents with increased lightening power" [0001] The present invention relates to bleaching agents for keratin containing fibers which, besides at least one oxidizing agent, additionally comprises imidazole or specific derivatives thereof as bleach enhancers, to the use of imidazole or specific derivatives thereof for increasing the lightening power of bleaching agents for keratin-containing fibers and to the use of imidazole or specific derivatives thereof for reducing the destructuring of keratin-containing fibers by oxidative processes, and to a method of lightening keratin-containing fibers using the bleaching agents according to the invention. [0002] Human hair is nowadays treated in diverse ways with hair cosmetic preparations. These include, for example, cleansing the hair with shampoos, care and regeneration with rinses and treatments, and bleaching, coloring and shaping the hair using colorants, tints, waving compositions and styling preparations. In this connection, agents for changing or nuancing the color of head hair play a prominent role. [0003] For permanent, intense colorations with corresponding fastness properties, so-called oxidation colorants are used. Such colorants usually comprise oxidation dye precursors, so-called developer components and coupler components. The developer components form the actual dyes under the influence of oxidizing agents with one another or with coupling with one or more coupler components. The oxidation colorants are characterized by excellent, long-lasting coloring results. [0004] In addition, lightening processes, so-called bleaching processes, are often used. The oxidizing agents present in the bleaching agents have an oxidative effect on the natural hair dye melanin and, if appropriate, on synthetic dyes present in the fiber and thereby cause a lightening of the hair -2- H0608OPCT color. The principles of bleaching and oxidative coloring processes are known to the person skilled in the art and summarized in relevant monographs, e.g. by K. Schrader, Grundlagen und Rezepturen der Kosmetika [Fundamentals and formulations of cosmetics], 2 nd Edition, 1989, Dr. Alfred HOthig Verlag, Heidelberg, or W. Umbach (Ed.), Kosmetik [Cosmetics], 2 nd Edition, 1995, Georg Thieme Verlag, Stuttgart, New York. [0005] For the lightening or bleaching of human hair - particularly for strand application, solid or paste-like preparations with solid oxidizing agents are usually mixed with a dilute hydrogen peroxide solution directly prior to use. This mixture is then applied to the hair and rinsed out again after a certain contact time. [0006] The abovementioned application mixture is referred to below as "bleaching agent". Unless stated otherwise, all of the quantities given refer exclusively to these application mixtures. [0007] Besides hydrogen peroxide, most of the conventional ready-to-use bleaching agents for keratin-containing fibers comprise peroxodisulfate compounds for increasing the lightening power and, upon application to the fibers, have a pH of greater than pH 9. The lightening power is optimal at this basic pH. However, under these conditions, firstly damage of the keratin containing fibers through destructuring of the fiber structure and secondly, upon application to the subject, skin irritations arise. Lowering the pH is accompanied by less hair damage and skin irritation, but also inevitably by a reduction in the lightening power. [0008] The laid-open specification JP-A-04 279514 relates to hair bleaching agents which have a mild effect on the keratin-containing fibers and the skin at a pH of from 5 to 8. These bleaching agents comprise hydrogen -3- H0608OPCT peroxide, persulfate and hydrogen carbonate. However, the lightening power of these bleaching agents does not satisfy the requirements of a high performance bleaching agent. [0009] An object of the present invention is therefore to improve the lightening power of bleaching agents for keratin-containing fibers, in order to provide more powerful bleaching agents with increased compatibility for the keratin-containing fibers. [0010] Surprisingly, it has now been found that the lightening power of bleaching agents for keratin-containing fibers, in particular in a pH range from 2.5 to 12.0, can be increased by adding imidazole or specific derivatives thereof and, moreover, the fiber structure of the keratin-containing fibers is destructured to a lesser degree during the lightening process. [0011] According to the invention, keratin-containing fibers are understood as meaning furs, wool, feathers and, in particular, human hair. [0012] The present invention therefore firstly provides the use of imidazole compounds according to formula I and/or physiologically acceptable salts thereof, (R) in which R1 is a hydrogen atom, an optionally substituted aryl group or a

(C

1

-C

6 )-alkyl group, -4- H0608OPCT R2 is a hydrogen atom, a carboxaldehyde group, a (C 1 -Cs)-alkyl group or a nitro group, R 3 is a hydrogen atom, a carboxy-(Cl-C6)-alkyl group, an amino

(C

1 -Cs)-alkyl group, a carboxyl group, a carboxaldehyde group, a

(C

1 -C)-alkyl group, a nitro group, a 2-amino-3-hydroxypropyl group or a group -CH 2

-CH(NH

2 )-COOH, R 4 is a hydrogen atom, a carboxaldehyde group or a carboxyl group, for increasing the lightening power of bleaching agents for keratin-containing fibers, in particular human hair. [0013] The imidazole compounds of formula I are used in particular at a pH in the range from pH 2.5 to 12.0, particularly preferably in the range from pH 4.5 to 10.0, for increasing the lightening power of bleaching agents. [0014] Preferably, the imidazole compounds according to formula I are chosen from a group formed from histamine, D-histidine, L-histidine, DL-histidine, D-histidinol, L-histidinol, DL-histidinol, imidazole, imidazole 4-acetic acid, imidazole-4-carboxylic acid, imidazole-4,5-dicarboxylic acid, imidazole-2-carboxaldehyde, imidazole-4-carboxaldehyde, imidazole 5-carboxaldehyde, 2-nitroimidazole, 4-nitroimidazole, 4-methylimidazole 5-carboxaldehyde, N-methylimidazole-2-carboxaldehyde, 4-methylimidazole, 2-methylimidazole, N-methylimidazole, N-(4-aminophenyl)imidazole, and the physiologically compatible salts of the abovementioned compounds. [0015] The invention secondly provides the use of imidazole compounds according to formula I and/or physiologically compatible salts thereof, -5- H0608OPCT R N (I) in which R', R 2 , R 3 and R 4 are as defined above, for reducing the destructuring of keratin-containing fibers, in particular human hair, through an oxidative treatment of the fibers. The oxidative treatment of the fibers can take place in the course of an oxidative coloration, but in particular in the course of an oxidative lightening (bleaching) and in the oxidative neutralizing step during a permanent shaping of keratin-containing fibers. [0016] The imidazole compounds of the first subject-matter are preferred. [0017] The degree of destructuring of the keratin-containing fibers can be determined experimentally by means of wet combability force measurement. The procedure for this measurement method is described in the experimental section of this application under point 3.0. [0018] The present invention thirdly provides agents for lightening keratin containing fibers comprising a combination of (a) at least one oxidizing agent and (b) an imidazole compound according to formula I and/or physiologically compatible salts thereof,

R

3 N R2 R1 -6- H06080PCT in which R 1 , R 2 , R 3 and R 4 are as defined above. [0019] The bleaching agents according to the invention comprise at least one oxidizing agent as a first important component. Hydrogen peroxide is preferably used as oxidizing agent according to the invention. The hydrogen peroxide is added to the bleaching agent according to the invention as a solution or in the form of a solid addition compound of hydrogen peroxide onto inorganic or organic compounds, such as, for example, sodium perborate, sodium percarbonate, magnesium percarbonate, sodium percarbamide, polyvinylpyrrolidone-nH 2

O

2 (n is a positive integer greater than 0), urea peroxide and melamine peroxide. [0020] As a further component essential to the invention, the bleaching agents of this invention comprise at least one imidazole compound according to formula I, preferably in an amount of from 0.1 to 10.0% by weight, particularly preferably in an amount of from 0.5 to 5.0% by weight, in each case based on the weight of the bleaching agent. [0021] The preferred imidazole compounds of the first subject-matter are preferred. [0022] Preferably, the agents according to the invention are free from oxidation dye precursors of the developer or coupler type. [0023] To further increase the lightening power, at least one optionally hydrated SiO 2 compound is added to the agent according to the invention. Although even small amounts of the optionally hydrated SiO 2 compounds increase the lightening power again, it may be preferred according to the invention to use the optionally hydrated SiO 2 compounds in amounts of from 0.05% by weight to 15% by weight, particularly preferably in amounts of from -7- H0608OPCT 0.15% by weight to 10% by weight and very particularly preferably in amounts of from 0.2% by weight to 5% by weight, in each case based on the total agent according to the invention. The quantitative data here in each case give the content of the SiO 2 compounds (without their water content) in the agents. [0024] With regard to the optionally hydrated SiO 2 compounds, the present invention is in principle subject to no limitations. Preference is given to salicic acids, oligomers and polymers thereof, and also salts thereof. Preferred salts are the alkali metal salts, in particular the potassium and sodium salts. The sodium salts are very particularly preferred. [0025] The optionally hydrated SiO 2 compounds can be present in different forms. According to the invention, preference is given to using the SiO 2 compounds in the form of silica gels or, particularly and preferably as waterglass. These SiO 2 compounds may sometimes be present in aqueous solution. [0026] According to the invention, very particular preference is given to waterglasses which are formed from a silicate of the formula (SiO 2 )n(Na2O)m(K20)p, where n is a positive rational number and m and p, independently of one another, are a positive rational number or are 0, with the provisos that at least one of the parameters m or p is different from 0 and the ratio between n and the sum of m and p is between 1:4 and 4:1. [0027] Besides the components described by the empirical formula, the waterglasses may also comprise further additives, such as, for example, phosphates or magnesium salts, in small amounts. [0028] Waterglasses which are particularly preferred according to the invention are sold, inter alia, by Henkel under the names Ferrosil* 119, -8- H0608OPCT Natronwasserglas 40/42, Portil* A, Portil* AW and Portil* W and by Akzo under the name Britesil* C20. [0029] Furthermore, the bleaching effect of the hydrogen peroxide can additionally be increased by peroxo compounds. These are usually peroxo compounds of the type which do not represent addition products of hydrogen peroxide onto other components. The choice of peroxo compounds potentially present in the agents according to the invention is subject in principle to no limitations; customary peroxo compounds known to the person skilled in the art are, for example, ammonium peroxydisulfate, potassium peroxydisulfate, sodium peroxydisulfate, ammonium persulfate, potassium persulfate, sodium persulfate, potassium peroxydiphosphate and peroxides, such as magnesium peroxide and barium peroxide. Among these peroxo compounds, which can also be used in combination, the inorganic compounds are preferred according to the invention. Particular preference is given to the peroxydisulfates, in particular ammonium peroxydisulfate. [0030] The peroxo compounds are present in the bleaching agents according to the invention preferably in amounts of 1-40% by weight, in particular in amounts of 2-30% by weight. [0031] The pH of the agents according to the invention is preferably in a pH range from pH 2.5 to 12.0, particularly preferably from pH 4.5 to 10.0. [0032] In a further embodiment, the bleaching agents according to the invention comprise at least one alkalinizing agent. According to the invention the customary alkalinizing agents known to the person skilled in the art for bleaching agents, such as ammonium, alkali metal and alkaline earth metal hydroxides, carbonates, hydrogen carbonates, hydroxycarbonates and carbamides, and also alkali metal phosphates can be used. The alkalinizing -9- H0608OPCT agent is preferably present in component A. [0033] In a preferred embodiment, the bleaching agents according to the invention comprise at least one alkalinizing agent chosen from ammonium, alkali metal and alkaline earth metal carbonates, hydrogen carbonates and carbamides. In this embodiment, the pH of the bleaching agent is preferably in a range from pH 7.5 to 12.0, particularly preferably in a range from pH 7.5 to 9.5, very particularly preferably in a range from 7.9 to 8.5. The addition of the selected alkalinizing agents of this embodiment again has a boosting effect on the degree of lightening of the keratin-containing fibers. [0034] The bleaching agents according to the invention comprise the alkalinizing agents preferably in amounts of from 0.2 to 25% by weight, in particular 0.5 to 10% by weight. [0035] As additional bleach boosters, the agents according to the invention can preferably comprise at least one organic compound with a carboxyl group, preferably chosen from acetic acid, lactic acid, tartaric acid, citric acid, salicylic acid and ortho-phthalic acid. [0036] In a further embodiment, the bleaching agents according to the invention additionally comprise further structure-improving active ingredients. Such active ingredients which improve the hair structure are vitamins and derivatives or precursors thereof. According to the invention, particular preference is given to panthenol and its physiologically compatible derivatives. Such derivatives are, in particular, the esters and ethers of panthenol, and cationically derivatized panthenols. Individual representatives are, for example, panthenol triacetate, panthenol monoethyl ether and its monoacetate, and also the cationic panthenol derivatives disclosed in WO 92/13829 Al. A panthenol derivative preferred according to the invention -10- H0608OPCT is also its precursor pantolactone. Panthenol is preferred within this group. A further example of a structure-improving vitamin is pyridoxine (vitamin B6). [0037] In addition, polyvinylpyrrolidone (PVP) is also known for its fiber structure-improving properties and is preferred according to the invention. [0038] Further structure-improving compounds which are particularly effective according to the invention are the aldehydes. Particularly preferred examples are formaldehyde and formaldehyde-cleaving compounds, such as, for example, methoxymethyl esters, dimethylol(thio)urea derivatives, oxazolidine derivatives, N-hydroxymethylmaleimide, hexamethylenetetramine and its derivatives, hydantoin derivatives, pyridinium-substituted dimethyl ethers, imidozolidenylurea derivatives, isothiazolinones, 2-bromo-2 nitropropanediol and 5-bromo-5-nitro-1,3-dioxane. Further particularly preferred aldehydes are acetaldehyde, glyoxal, glycerin aldehyde and glutardialdehyde. [0039] A further suitable group of structure-improving active ingredients are plant extracts. [0040] Usually, these extracts are prepared by extraction of the total plant. In individual cases, however, it may also be preferred to produce the extracts exclusively from flowers and/or leaves of the plant. [0041] With regard to the plant extracts which can be used according to the invention, reference is made in particular to the extracts which are listed in the table starting on page 44 of the third edition of the introduction to the ingredients declaration of cosmetic compositions, published by the Industrieverband K6rperpflege- und Waschmittel e.V. [German Cosmetic, Toiletry, Perfumery and Detergent Association] (IKW), Frankfurt.

-11 - H0608OPCT [0042] According to the invention, the extracts of oak bark, stinging nettle, hamamelis, hops, chamomile, burdock, horsetail, hawthorn, linden blossom, almond, aloe vera, fir needle, roast chestnut, sandalwood, juniper, coconut, mango, apricot, lemon, wheat, kiwi, melon, orange, grapefruit, sage, rosemary, birch, mallow, lady's smock, wild thyme, yarrow, thyme, Melissa, restharrow, coltsfoot, marshmallow, meristem, green tea, ginseng and ginger root are particularly preferred. [0043] Particular preference is given to the extracts from oak bark, stinging nettle, hamamelis, hops, chamomile, burdock, horsetail, linden blossom, almond, aloe vera, coconut, mango, apricot, lemon, wheat, kiwi, melon, orange, grapefruit, sage, rosemary, birch, lady's smock, wild thyme, yarrow, restharrow, meristem, green tea, ginseng and ginger root. [0044] Of very particular suitability for the compositions according to the invention are the extracts of almond, aloe vera, coconut, mango, apricot, lemon, wheat, kiwi, melon and green tea. [0045] Extractants which can be used for producing the specified plant extracts are water, alcohols, and mixtures thereof. Among the alcohols, preference is given here to lower alcohols, such as ethanol and isopropanol, but in particular polyhydric alcohols, such as ethylene glycol and propylene glycol, either as the sole extractant or in a mixture with water. Plant extracts based on water/propylene glycol in the ratio 1:10 to 10:1 have proven to be particularly suitable. [0046] According to the invention, the plant extracts can either be used in pure form or in dilute form. If they are used in dilute form, they usually comprise about 2-80% by weight of active substance and, as solvent, the extractant or extractant mixture used during their extraction.

-12- H06080PCT [0047] In addition, it may be preferred to use mixtures of two or more, in particular of two, different plant extracts in the agents according to the invention. [0048] According to the invention, as structure-improving active ingredients, preference is likewise given to honey extracts. These extracts are obtained in an analogous way to the plant extracts and comprise usually 1-10% by weight, in particular 3-5% by weight, of active substance. Water/propylene glycol mixtures may also be extractants which are preferred here. [0049] Further structure-improving active ingredients are protein hydrolysates, in particular elastin, collagen, keratin, milk protein, soya protein, almond protein and wheat protein hydrolysates, their condensation products with fatty acids, and also quaternized protein hydrolysates. Particular preference is given to greatly degraded keratin hydrolysates with molar masses in the range from 400 to 800. In addition, quaternized protein hydrolysates, as are sold, for example, under the trade names Gluadin* WQ (INCI name: Laurdimonium Hydroxypropyl Hydrolyzed Wheat Protein) and Crotein* Q (INCI name: Hydroxypropyltrimonium Hydrolyzed Collagen), are particularly preferred according to the invention. [0050] Besides the quaternized protein hydrolysates, quaternary polymers also represent structure-improving compounds preferred according to the invention. Particular preference is given to the polymers which are sold under the trade names Mirapol* A15 (INCI name: Polyquaternium-2), Onamer* M (INCI name: Polyquaternium-1) and Merquat* 100 (INCI name: Polyquaternium-6), Polymer JR 400 (INCI name: Polyquaternium-1 0). [0051] Further fiber structure-improving active ingredients are mono-, di and oligosaccharides, such as, for example, glucose, galactose, fructose, fruit -13- H0608OPCT sugar, sucrose and lactose. In addition, according to the invention, it is also possible to use derivatives of these pentoses, hexoses and heptoses, such as the corresponding aldonic and uronic acids (sugar acids), sugar alcohols, sugar amines, such as, for example, N-glucosamine, and glycosides, and also pentoses, hexoses and heptoses etherified with C 4

-C

3 0-fatty alcohols. According to the invention, the sugar acids can be used in free form, in the form of their salts, preference being given to calcium, magnesium and zinc salts, and in the form of their esters or lactones. Preferred sugar acids are gluconic acid, glucono-y-lactone, lactobionic acid, glucuronic acid and its mono- or dilactones, pangamic acid, sugar acid, mannosaccharic acid and its mono- or dilactones, and mucic acid and its mono- or dilactones. Preferred sugar alcohols are sorbitol, mannitol and dulcitol. Preferred glycosides are the methylglucosides. Glucose, N-glucosamine and gluconic acid are particularly preferred from this group. [0052] For the purposes of the present invention, certain amino acids can also be used as active ingredients which improve hair structure. Examples are the amino acids serine, threonine and tyrosine described in DE-195 22 569, which is hereby expressly incorporated by reference. In addition, derivatives of serine, such as, for example, serine phosphate, are also preferred according to the invention. A further structure-improving amino acid is lysine. Serine is a particularly preferred active ingredient which improves fiber structure. [0053] Certain acids, in particular a-hydroxycarboxylic acids, and their salts can likewise be used for improving structure. Structure-improving acids preferred according to the invention are lactic acid, malic acid, tartaric acid, glyceric acid and maleic acid. Lactic acid and glyceric acid are particularly preferred. In addition, specific phosphonic acids and their salts improve the structure of keratin-containing fibers. Phosphonic acids preferred according to the invention are n-octylphosphonic acid and n-decylphosphonic acid.

-14- H0608OPCT [0054] Furthermore, lipid-soluble ester alcohols or ester polyols are known for their structure-improving effect. They are regarded as being lipid-soluble if 5% by weight of these products dissolve in cetyl alcohol at 80 0 C to give a clear solution. [0055] The ester alcohols or ester polyols suitable according to the invention are obtainable by reacting an epoxy fatty acid ester with water for mono- or polyhydric alcohols having 1-10 carbon atoms with opening of the epoxide ring and formation of a vicinal dihydroxyethyl or hydroxyalkoxyethyl group. The epoxy fatty acid ester here can also be an epoxidation product of a technical-grade fatty acid ester with fractions of saturated fatty acids. The epoxide oxygen content should, however, be at least 3% by weight, preferably 5-10% by weight. [0056] The epoxy fatty acid esters here are either epoxidized fatty acid esters of monohydric alcohols, i.e., for example, epoxidized oleic acid methyl ester, linoleic acid methyl ester, ricinoleic acid methyl ester or epoxidized fatty acid esters of polyhydric alcohols, e.g. glycerol monooleate or propylene glycol monooleate or epoxidized fatty acid triglycerides, e.g. oleic acid triglyceride or unsaturated oils, such as, for example, olive oil, soya oil, sunflower oil, linseed oil, rapeseed oil. [0057] Of particular interest from an industrial point of view are primarily unsaturated fatty acid methyl ester epoxides of unsaturated plant fatty acids. Thus, as ester polyol, the reaction product of a plant oil fatty acid methyl ester epoxidate with a polyol having 2-6 carbon atoms and 2-6 hydroxyl groups is particularly preferred. Polyols which may be present here are, for example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, butanediol, pentanediol, hexanediol, glycerol, trimethylolpropane, pentaerythritol, sorbitol or diglycerol.

-15- H06080PCT [0058] Of particularly good suitability here for the bleaching agents according to the invention as ester polyol is the reaction product of a plant fatty acid methyl ester epoxidate with trimethylpropane and with a hydroxyl number of 350-450. Such a product based on soya oil fatty acid methyl ester epoxide and trimethylolpropane is available under the trade name Sovermol* 760. [0059] In addition, vitamin B3 can be used as structure-improving active ingredient. This name often covers the compounds nicotinic acid and nicotinamide (niacinamide). According to the invention, preference is given to nicotinamide. [0060] For the purposes of the present invention, it is also possible to use vitamin H as structure-improving active ingredient. Vitamin H refers to the compound (3aS, 4S, 6aR)-2-oxohexahydrothienol[3,4-d]imidazole-4-valeric acid, for which, however, the trivial name biotin has in the meantime become accepted. [0061] Structure-improving active ingredients which are particularly preferred according to the invention are chosen from panthenol, physiologically compatible panthenol derivatives, mono-, di- and oligosaccharides, serine, lactic acid, glyceric acid, niacinamide, vitamin B6, polyvinylpyrrolidone, glucose, gluconic acid, biotin and the lipid-soluble ester alcohols or ester polyols. [0062] The agents according to the invention comprise the structure improving active ingredients preferably in amounts of from 0.1 to 5% by weight, particularly preferably in amounts of from 0.2 to 2% by weight. [0063] In a preferred embodiment of the present invention, the agents -16 - H0608OPCT further comprise a magnesium compound. The agents according to the invention can be further optimized with regard to their structure-retaining properties by adding Mg2+ cations. Preferred magnesium compounds are inorganic and organic Mg 2 + salts, such as, for example, the halides, the carbonates and hydrogen carbonates, the acetate and the citrate. [0064] The agents according to the invention can furthermore comprise all active ingredients, additives and auxiliaries known for such preparations. In many cases, the bleaching agents comprise at least one surfactant, where in principle either anionic or zwitterionic, ampholytic, nonionic and cationic surfactants are suitable. In many cases, however, it has proven to be advantageous to choose the surfactant from anionic, zwitterionic or nonionic surfactants. [0065] Suitable anionic surfactants in preparations according to the invention are all anionic surface-active substances suitable for use on the human body. These are characterized by a water-solubilizing, anionic group, such as, for example, a carboxylate, sulfate, sulfonate or phosphate group, and a lipophilic alkyl group having about 10 to 22 carbon atoms. In addition, glycol or polyglycol ether groups, ester, ether and amide groups, and hydroxyl groups may be present in the molecule. Examples of suitable anionic surfactants are, in each case in the form of the sodium, potassium and ammonium and the mono-, di- and trialkanolammonium salts having 2 or 3 carbon atoms in the alkanol group, - linear fatty acids having 10 to 22 carbon atoms (soaps), - ethercarboxylic acids of the formula R-O-(CH 2

-CH

2 0)x-CH 2 -COOH, in which R is a linear alkyl group having 10 to 22 carbon atoms and x = 0 or 1 to 16, - acyl sarcosides having 10 to 18 carbon atoms in the acyl group, - acyl taurides having 10 to 18 carbon atoms in the acyl group, -17- H0608OPCT - acyl isothionates having 10 to 18 carbon atoms in the acyl group, - sulfosuccinic mono- and dialkyl esters having 8 to 18 carbon atoms in the alkyl group and sulfosuccinic monoalkyl polyoxyethyl esters having 8 to 18 carbon atoms in the alkyl group and 1 to 6 oxyethyl groups, - linear alkanesulfonates having 12 to 18 carbon atoms, - linear alpha-olefinsulfonates having 12 to 18 carbon atoms, - alpha-sulfo fatty acid methyl esters of fatty acids having 12 to 18 carbon atoms, - alkyl sulfates and alkyl polyglycol ether sulfates of the formula

R-O(CH

2

-CH

2

O)-SO

3 H, in which R is a preferably linear alkyl group having 10 to 18 carbon atoms and x = 0 or 1 to 12, - mixtures of surface-active hydroxysulfonates as in DE-A-37 25 030, - sulfated hydroxyalkyl polyethylene and/or hydroxyalkylene propylene glycol ethers as in DE-A-37 23 354, - sulfonates of unsaturated fatty acids having 12 to 24 carbon atoms and 1 to 6 double bonds as in DE-A-39 26 344, - esters of tartaric acid and citric acid with alcohols, which constitute addition products of about 2-15 molecules of ethylene oxide and/or propylene oxide onto fatty alcohols having 8 to 22 carbon atoms. [0066] Preferred anionic surfactants are alkyl sulfates, alkyl polyglycol ether sulfates and ethercarboxylic acids having 10 to 18 carbon atoms in the alkyl group and up to 12 glycol ether groups in the molecule, and in particular salts of saturated and in particular unsaturated C 8

-C

22 -carboxylic acids, such as oleic acid, stearic acid, isostearic acid and palmitic acid. [0067] Zwitterionic surfactants is the term used to refer to those surface active compounds which carry in the molecule at least one quaternary ammonium group and at least one -COO( or -SO3( group. Particularly -18- H0608OPCT suitable zwitterionic surfactants are the so-called betaines, such as the N-alkyl-N,N-dimethylammonium glycinates, for example cocoalkyldimethyl ammonium glycinate, N-acylaminopropyl-N,N-dimethylammonium glycinate, for example cocoacylaminopropyldimethylammonium glycinate, and 2-alkyl-3 carboxymethyl-3-hydroxyethylimidazolines having in each case 8 to 18 carbon atoms in the alkyl or acyl group, and cocoacylaminoethyl hydroxyethylcarboxy methyl glycinate. A preferred zwitterionic surfactant is the fatty acid amide derivative known under the INCI name Cocamidopropyl Betaine. [0068] Ampholytic surfactants are understood as meaning those surface active compounds which, apart from a C8.

18 -alkyl or acyl group in the molecule, contain at least one free amino group and at least one -COOH or

-SO

3 H group and are capable of forming internal salts. Examples of suitable ampholytic surfactants are N-alkylglycines, N-alkylpropionic acids, N-alkyl aminobutyric acids, N-alkylaminodipropionic acids, N-hydroxyethyl-N-alkyl propylglycines, N-alkyltaurines, N-alkylsarcosines, 2-alkylaminopropionic acids and alkylaminoacetic acids having in each case about 8 to 18 carbon atoms in the alkyl group. Particularly preferred ampholytic surfactants are N-coco alkylaminopropionate, cocoacylaminoethylaminopropionate and C 1 2-1 8 -acyl sarcosine. [0069] Nonionic surfactants comprise, as hydrophilic group, e.g. a polyol group, a polyalkylene glycol ether group or a combination of polyol and polyglycol ether group. Such compounds are, for example, - addition products of from 2 to 30 mol of ethylene oxide and/or 0 to 5 mol of propylene oxide onto linear fatty alcohols having 8 to 22 carbon atoms, onto fatty acids having 12 to 22 carbon atoms and onto alkylphenols having 8 to 15 carbon atoms in the alkyl group, - C 12

-

2 2 fatty acid mono- and diesters of addition products of from I to 30 mol of ethylene oxide onto glycerol, -19- H0608OPCT - C 8

-

22 -alkyl mono- and oligoglycosides and ethoxylated analogues thereof, - addition products of from 5 to 60 mol of ethylene oxide onto castor oil and hydrogenated castor oil, - addition products of ethylene oxide onto sorbitan fatty acid esters - addition products of ethylene oxide onto fatty acid alkanolamides. [0070] Examples of the cationic surfactants which can be used in the bleaching agents according to the invention are, in particular, quaternary ammonium compounds. Preference is given to ammonium halides, such as alkyltrimethylammonium chlorides, dialkyldimethylammonium chlorides and trialkylmethylammonium chlorides, e.g. cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, distearyldimethylammonium chloride, lauryldimethylammonium chloride, lauryldimethylbenzylammonium chloride and tricetylmethylammonium chloride. Further cationic surfactants which can be used according to the invention constitute the quaternized protein hydrolysates. [0071] Likewise suitable according to the invention are cationic silicone oils, such as, for example, the commercially available products Q2-7224 (manufacturer: Dow Corning; a stabilized trimethylsilylamodimethicone), Dow Corning 929 emulsion (comprising a hydroxylamino-modified silicone, which is also referred to as amodimethicone), SM-2059 (manufacturer: General Electric), SLM-55067 (manufacturer: Wacker), and Abil*-Quat 3270 and 3272 (manufacturer: Th. Goldschmidt; diquaternary polydimethylsiloxanes, quaternium-80). [0072] Alkylamidoamines, in particular fatty acid amidoamines, such as the stearylamidopropyldimethylamine obtainable under the name Tego Amid* S 18, are characterized not only by a good conditioning effect, but specifically by -20- H06080PCT their good biodegradability. Likewise of very good biodegradability are quaternary ester compounds, so-called "ester quats", such as the methyl hydroxyalkyldialkoyloxyalkylammonium methosulfates sold under the trade name Stepantex*, and also the products sold under the trade name Dehyquart*, such as Dehyquart* AU-46. [0073] One example of a quaternary sugar derivative which can be used as cationic surfactant is the commercial product Glucquat*100, according to INCI nomenclature a "Lauryl Methyl Gluceth-10 Hydroxypropyl Dimonium Chloride". [0074] The compounds with alkyl groups used as surfactants may in each case be uniform substances. It is, however, usually preferred when preparing these substances to start from native vegetable or animal raw materials, giving mixtures of substances with varying alkyl chain lengths which depend on the particular raw material. [0075] Surfactants which constitute addition products of ethylene oxide and/or propylene oxide onto fatty alcohols or derivatives of these addition products which may be used are either products with a "normal" homologue distribution, or those with a narrowed homologue distribution. In this connection, "normal" homologue distribution is understood as meaning mixtures of homologues which are obtained during the reaction of fatty alcohol and alkylene oxide using alkali metals, alkali metal hydroxides or alkali metal alkoxides as catalysts. By contrast, narrowed homologue distributions are obtained if, for example, hydrotalcites, alkaline earth metal salts of ether carboxylic acids, alkaline earth metal oxides, hydroxides or alkoxides are used as catalysts. The use of products with a narrowed homologue distribution may be preferred. [0076] In addition, the bleaching agents according to the invention can -21 - H06080PCT preferably also comprise a conditioning active ingredient chosen from the group which is formed by cationic surfactants, cationic polymers, alkylamido amines, paraffin oils, vegetable oils and synthetic oils. [0077] As conditioning active ingredients, cationic polymers may be preferred. These are generally polymers which comprise a quaternary nitrogen atom, for example in the form of an ammonium group. [0078] Preferred cationic polymers are, for example, - quaternized cellulose derivatives, as are commercially available under the names Celquat* and Polymer JR*. The compounds Celquat* H 100, Celquat* L200 and Polymer JR* 400 are preferred quaternized cellulose derivatives. - Polymeric dimethyldiallylammonium salts and copolymers thereof with acrylic acid, and esters and amides of acrylic acid and methacrylic acid. The products available commercially under the names Merquat* 100 (poly(dimethyldiallylammonium chloride)), Merquat* 550 (dimethyldiallylammonium chloride-acrylamide copolymer) and Merquat* 280 (dimethyldiallylammonium chloride acrylic acid copolymer are examples of such cationic polymers. - Copolymers of vinylpyrrolidone with quaternized derivatives of dialkylaminoacrylate and -methacrylate, such as, for example, vinylpyrrolidone-dimethylaminomethacrylate copolymers quaternized with diethyl sulfate. Such compounds are commercially available under the names Gafquat* 734 and Gafquat* 755. - Vinylpyrrolidone-methoimidazolinium chloride copolymers, as are supplied under the name Luviquat*. - Quaternized polyvinyl alcohol and the polymers known under the names - Polyquaternium 2, -22- H0608OPCT - Polyquaternium 17, - Polyquaternium 18 and - Polyquaternium 27 with quaternary nitrogen atoms in the polymer main chain. [0079] Particular preference is given to cationic polymer from the first four groups, and very particular preference is given to polyquaternium-2, polyquaternium-10 and polyquaternium-22. [0080] Also suitable as conditioning active ingredients are silicone oils, in particular dialkyl- and alkylarylsiloxanes, such as, for example, dimethylpoly siloxane and methylphenylpolysiloxane, and alkoxylated and quaternized analogues thereof. Examples of such silicones are the products sold by Dow Corning under the names DC 190, DC 200, DC 344, DC 345 and DC 1401, and the commercial products Q2-7224 (manufacturer: Dow Corning; a stabilized trimethylsilylamodimethicone), Dow Corning* 929 emulsion (comprising a hydroxylamino-modified silicone, which is also referred to as amodimethicone), SM-2059 (manufacturer: General Electric), SLM-55067 (manufacturer: Wacker), and Abil*-Quat 3270 and 3272 (manufacturer: Th. Goldschmidt; diquaternary polydimethylsiloxanes, quaternium-80). [0081] As conditioning active ingredients it is likewise possible to use paraffin oils, synthetically prepared oligomeric alkenes, and vegetable oils, such as jojoba oil, sunflower oil, orange oil, almond oil, wheatgerm oil and peach kernel oil, and also tocopherol acetate. [0082] Equally suitable hair-conditioning compounds are phospholipids, for example soya lecithin, egg lecithin and cephalins. [0083] Further active ingredients, auxiliaries and additives are, for example, -23- H06080PCT - nonionic polymers, such as, for example, vinylpyrrolidone/vinyl acrylate copolymers, polyvinylpyrrolidone and vinyl pyrrolidone/vinyl acetate copolymers and polysiloxanes, - zwitterionic and amphoteric polymers, such as, for example, acrylamidopropyltrimethylammonium chloride/acrylate copolymers and octylacrylamide/methyl methacrylate/tert-butylaminoethyl methacrylate/2-hydroxypropyl methacrylate copolymers, - anionic polymers, such as, for example, polyacrylic acids, crosslinked polyacrylic acids, vinyl acetate/crotonic acid copolymers, vinylpyrrolidone/vinyl acrylate copolymers, vinyl acetate/butyl maleate/isobornyl acrylate copolymers, methyl vinyl ether/maleic anhydride copolymers and acrylic acid/ethyl acrylate/N-tert butylacrylamide terpolymers, - thickeners, such as agar agar, guar gum, alginates, xanthan gum, gum Arabic, karaya gum, carob seed grain, linseed gums, dextrans, cellulose derivatives, e.g. methylcellulose, hydroxyalkylcellulose and carboxymethylcellulose, starch fractions and derivatives, such as amylose, amylopectin and dextrins, clays, such as, for example, bentonite or completely synthetic hydrocolloids, such as, for example, polyvinyl alcohol, - structurants, such as maleic acid and lactic acid, - protein hydrolysates, in particular elastin, collagen, keratin, milk protein, soya protein and wheat protein hydrolysates, condensation products thereof with fatty acids, and quaternized protein hydrolysates, - perfume oils, - cyclodextrins, - solvents and solubility promoters, such as ethanol, isopropanol, ethylene glycol, propylene glycol, glycerol, dimethyl isosorbide and diethylene glycol, -24- H0608OPCT - quaternized amines, such as methyl-1-alkylamidoethyl-2-alkylimida zolinium methosulfate - antifoams, such as silicones, - dyes for coloring the agent, - antidandruff active ingredients, such as piroctone olamine, zinc omadine and climbazole, - photoprotective agents, in particular derivatized benzophenones, cinnamic acid derivatives and triazines, - substances for adjusting the pH, such as, for example, customary acids, in particular food acids and bases, - active ingredients, such as allantoin, pyrrolidonecarboxylic acids and salts thereof, and bisabolol, - cholesterol, - consistency regulators, such as sugar esters, polyol esters or polyol alkyl ethers, - fats and waxes, such as spermaceti, beeswax, montan wax and paraffins, - fatty acid alkanolamides, - complexing agents, such as EDTA, NTA, p-alaninediacetic acid and phosphonic acids, - swelling and penetration 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, - pearlizing agents, such as ethylene glycol mono- and stearate, and PEG-3 distearate, - pigments, - stabilizers for hydrogen peroxide and other oxidizing agents, - propellants, such as propane/butane mixtures, N 2 0, dimethyl ether, -25- H0608OPCT

CO

2 and air, - antioxidants. [0084] With regard to further optional components and the amounts of these components used, reference is expressly made to the relevant handbooks known to the person skilled in the art, e.g. Kh. Schrader, Grundlagen und Rezepturen der Kosmetika [Fundamentals and formulations of cosmetics], 2 nd Edition, H(thig Buch Verlag, Heidelberg, 1989. [0085] The present invention fourthly provides a method of lightening keratin-containing fibers, in which the fibers are treated with the agent of the third subject-matter of the invention described above. [0086] Within the context of this process, the bleaching agents according to the invention of the third subject-matter of the invention are prepared preferably just prior to use on the fibers by combining at least two components. For this purpose, one component A which may optionally comprise a peroxo compound is mixed with a hydrogen peroxide solution as component B, the mixture preferably having the abovementioned pH. The imidazole compound according to formula I is a constituent of at least one of components A and B. However, it is preferably present in component A. Component A is preferably present as a cream, paste, a W/O emulsion, an O/W emulsion or an oil. [0087] Component A in turn can, however, in a further variant according to the invention of this embodiment, also be prepared from a component Al and a component A2 comprising at least one peroxo compound by mixing. In this connection, component Al is preferably in the form of a W/O or O/W emulsion, and component A2 is in the form of a solid.

-26- H06080PCT [0088] The concentration of the hydrogen peroxide solution in component B is determined firstly by the legal provisions and secondly by the desired effect; as a rule, 6 to 12% strength solutions in water are used. The quantitative ratios of component A and of component B are here usually in the range 1.5:1 to 1:2, an excess of component A being chosen particularly if the desired bleaching effect is not to be too marked. [0089] The examples below serve to illustrate the subject-matter of the present invention, but without limiting it. E example s 1.0 Preparation of the bleaching agents [0090] The following cream base A and B as in table 1 was prepared: Table 1: Formulation of the cream base Hydrenol* D' 12.00% by wt. Kokoslorol* C12-18 2 2.40% by wt. Texapon* NSO F 3 26.50% by wt. Methyl paraben 0.20% by wt. Propyl paraben 0.20% by wt. Ammonium sulfate 1.00% by wt. Sodium waterglass 40/424 0.50% by wt. Phenoxyethanol 0.40% by wt. Water ad 100 1 C 1 6

-C

1 8 -fatty alcohol (INCI name: Cetearyl alcohol) (COGNIS) 2 C 1 2

-C

1 8 -fatty alcohol (INCI name: Coconut alcohol) (COGNIS) 3 Lauryl ether sulfate, sodium salt (about 27.5% active substance; (INC[ name: Sodium Laureth Sulfate) (COGNIS) -27- H0608OPCT 4 INCI name: Sodium Silicate (COGNIS) [0091] The ready-to-use bleaching agents were prepared by mixing the components from table 2 with stirring. Formulations El to E4 are in accordance with the invention, formulations V1 to V4 are comparison formulations. Table 2: Formulation No. El E2 E3 E4 V1 V2 V3 V4 [g] [g] [g] [g] [g] [g] [g] [g] Cream base 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 (as in table 1) Imidazole 3.00 3.00 3.00 3.00 - - - (NH4)2CO 3 - 2.00 - 2.00 - - - (NH 4

)

2

S

2 0 8 - - 12.50 12.50 - 12.50 - 12.50 Developer 50.00 50.00 50.00 50.00 50.00 50.00 50.00 50.00 (as in table 3) Ammonia - - 0.35 - 0.90 1.30 3.20 8.80 (25% strength aqueous solution) pH 8.0 8.0 8.0 8.0 8.0 8.0 9.5 9.5 Table 3: Developer formulation Dipicolinic acid 0.10% by wt. Na 2

H

2

P

2 0 7 0.03% by wt. Turpinal* SL 5 1.50% by wt. Texapon* N 286 2.00% by wt. Dow Corning DB 110 7 0.07% by wt. Aculyn* 338 12.00% by wt. Hydrogen peroxide 12.00% by wt. Ammonia (25% strength aqueous solution) 0.65% by wt. Water ad 100 -28- H06080PCT 5 1-Hydroxyethane-1,1-diphosphonic acid (about 60% active substance; INCI name: Etidronic Acid) (Cognis) 6 Sodium lauryl ether sulfate (about 28% active substance; INCI name: Sodium Laureth Sulfate) (Cognis) Nonionogenic silicone emulsion (about 10% active substance; INCI name: Dimethicone) (Dow Corning) 8 Aqueous acrylate dispersion (about 28% active substance; INCI name: Acrylates Copolymer) (Rohm & Haas) 2.0 Application and colorimetry measurements [0092] The degree of lightening was determined on standardized hair swatches (Fischbach & Miller 6923) by colorimetric measurements of the fibers. In each case, for every 1 g of hair swatch, 4 g of a bleaching agent prepared in point 1.0 of table 2 are applied to the hair swatch and left there for 45 minutes at a temperature of 32*C. The agent was then rinsed from the swatch with water. The hair was finally dried and measured colorimetrically using the Texflash DC 3881 instrument from Datacolor to determine the CIE Lab values. [0093] Table 4 summarizes the measured L value of the CIE-lab values. The greater the L value, the higher the lightening power. Table 4: L value Bleaching agent El 39.30 Bleaching agent E2 44.02 Bleaching agent E3 52.83 Bleaching agent E4 56.59 Bleaching agent V1 35.17 -29- H0608OPCT Bleaching agent V2 48.76 Bleaching agent V3 37.19 Bleaching agent V4 60.10 3.0 Carrying out the wet combing force measurements 3.1 Pretreatment of the test hair swatches [0094] For each bleaching agent to be tested and for the blank determination, in each case 20 hair swatches, prewashed with a 2% strength by weight Texapon NSO solution (Alkinco 6634, natural dark European from Alkinco) were used. 3.2 Incubation with the test solution [0095] The bleaching agent E3 according to the invention was tested in comparison to the noninventive bleaching agent V2. [0096] Per bleaching agent, 20 hair swatches were incubated over a period of 45 minutes in the bleaching agent to be tested and then rinsed with tap water (water temperature 38 0 C, flow rate 1 I/minute) under standard conditions. The hair swatches were stored after bleaching for 48 hours before measuring the wet combing work. 3.3 Measurement of the wet combing work [0097] Before the wet combing work of the hair swatches was measured, the hair swatches were precombed in a precombing apparatus over a period of 105 seconds. During this, the hair swatch is wetted with tap water (water temperature 32*C, flow rate 0.5 I/minute). Then, for each swatch, the work which has to be applied for 10 combing operations is determined in the measuring apparatus by means of a dynamometer. The value from the measured combing work averaged over the -30- H0608OPCT 20 swatches gives the respective wet combing work. 3.4 Test results [0098] The blank is the averaged measurements from point 3.3 of 20 hair swatches which have only been pretreated according to point 3.1. [0099] The percentages given in table 5 represent the increase in the wet combing work compared to the wet combing work of the blank determined as described above. The higher the value, the more the hair fiber was destructured by the bleaching agent. The L values in table 5 were taken from table 4 (see point 2.0). Table 5: E3 V2 Increase in the wet 26.0% 32.1% combing work [%] L value as in table 4 52.83 48.76 [0100] As has been demonstrated, the bleaching agents according to the invention have a higher lightening power coupled with lower destructuring of the hair fiber.

Claims (19)

1. 2. The use of imidazole compounds according to formula I and/or physiologically compatible salts thereof, -32- H0608OPCT R 3 N R (I) in which R 1 , R 2 , R 3 and R 4 are as defined in claim 1, for reducing the destructuring of keratin-containing fibers, in particular human hair, by oxidative processes.
2. 3. An agent for lightening keratin-containing fibers, in particular human hair, comprising (a) at least one oxidizing agent and (b) at least one imidazole compound according to formula I and/or physiologically compatible salts thereof 2 R1 (1) in which R 1 , R 2 , R 3 and R 4 are as defined in claim 1.
3. 4. The agent as claimed in claim 3, characterized in that it comprises the imidazole compounds of the formula I in an amount of from 0.1 to 10% by weight, based on the weight of the total agent.
4. 5. The agent as claimed in claim 3, characterized in that it has a pH of from 4.5 to 12.0.
5. 6. The agent as claimed in one of claims 3 to 5, characterized in that it -33- H06080PCT additionally comprises at least one optionally hydrated SiO 2 compound.
6. 7. The agent as claimed in claim 6, characterized in that the optionally hydrated SiO 2 compound is a silicate of the formula (SiO 2 )n(Na 2 O)m(K20)p, where n is a positive rational number and m and p, independently of one another, are a positive rational number or are 0, with the provisos that at least one of the parameters m or p is different from 0 and the ratio between n and the sum of m and p is between 1:4 and 4:1.
7. 8. The agent as claimed in either of claims 6 and 7, characterized in that the optionally hydrated SiO 2 compound is an aqueous solution of the silicate of the formula (SiO 2 )n(Na 2 O)m(K 2 0)p, in which n, m and p are as defined in claim 8.
8. 9. The agent as claimed in one of claims 6 to 8, characterized in that the optionally hydrated SiO 2 compound is a silica gel.
9. 10. The agent as claimed in one of claims 6 to 9, characterized in that it comprises the optionally hydrated SiO 2 compounds in an amount of from 0.05 to 15% by weight.
10. 11. The agent as claimed in one of claims 3 to 10, characterized in that it additionally comprises at least one alkalinizing agent.
11. 12. The agent as claimed in one of claims 3 to 11, characterized in that the alkalinizing agent is chosen from ammonium, alkali metal and alkaline earth metal carbonates, hydrogen carbonates and carbamides.
12. 13. The agent as claimed in claim 12, characterized in that it has a pH of -34- H0608OPCT from 7.5 to 12.0.
13. 14. The agent as claimed in one of claims 3 to 13, characterized in that a structure-improving active ingredient chosen from panthenol, physiologically compatible panthenol derivatives, mono-, di- and oligosaccharides, serine, glyceric acid, niacinamide, vitamin B6, polyvinylpyrrolidone, gluconic acid, biotin and the lipid-soluble ester alcohols or ester polyols is additionally present.
14. 15. The agent as claimed in claim 14, characterized in that it comprises the structure-improving active ingredient in amounts of from 0.1 to 5% by weight.
15. 16. The agent as claimed in one of claims 3 to 15, characterized in that it further comprises a magnesium compound.
16. 17. The agent as claimed in one of claims 3 to 16, characterized in that it additionally comprises at least one peroxo compound.
17. 18. The agent as claimed in claim 17, characterized in that the peroxo compound is chosen from ammonium peroxydisulfate, potassium peroxydisulfate, sodium peroxydisulfate, ammonium persulfate, potassium persulfate, sodium persulfate, potassium peroxydiphosphate, magnesium peroxide and barium peroxide.
18. 19. The agent as claimed in one of claims 3 to 18, characterized in that at least one organic compound with a carboxyl group, in particular chosen from acetic acid, lactic acid, tartaric acid, citric acid, salicylic acid and ortho-phthalic acid is additionally present. -35- H0608OPCT
19. 20. A method of lightening keratin-containing fibers, characterized in that the fibers are treated with an agent as claimed in one of claims 3 to 19.