Bleaching method and bleaching kit with improved lightening result

Abstract

The present invention relates to a method for oxidatively lightening keratin fibers, in particular human hair, and to a kit for carrying out the lightening method. The method according to the invention allows, without the use of additional oxidant, an increase in lightening power and a reduction in an undesired shift towards red of the bleaching result.

Description

[0001] “Bleaching process and bleaching kit with improved lightening results”

[0002] The invention relates to a method for the oxidative lightening of keratin fibers, in particular human hair, as well as a kit for carrying out this lightening process. The method according to the invention allows the lightening performance to be increased without the need for additional oxidizing agents and reduces the undesirable red shift in the bleaching result.

[0003] Changing the shape and color of hair represents an important area of ​​modern cosmetics. This allows the appearance of hair to be adapted both to current fashion trends and the individual's wishes. Permanent waving and other hair-shaping procedures can be used almost independently of the type of hair being treated. In contrast, coloring and especially bleaching procedures are limited to certain original hair colors. For example, lightening procedures, known as bleaching, essentially only work with dark blonde or lighter hair. There is still a need for effective methods, especially for bleaching darker original hair colors.

[0004] To bleach human hair, solid or paste-like preparations containing solid oxidizing agents are usually mixed with a diluted hydrogen peroxide solution immediately before use. This mixture is then applied to the hair and rinsed out after a certain exposure time.

[0005] To achieve sufficient lightening performance, such products are typically highly alkaline, with a pH value between 9 and 10.5. Such high pH values ​​are necessary to ensure the opening of the outer cuticle layer and thus allow the active species (hydrogen peroxide) to penetrate the hair.

[0006] In order to achieve large color differences during the bleaching process, i.e. in particular to decolorize dark or black hair, bleach activators such as persalts as additional peroxide sources and / or carbonates as additional alkalizing agents are usually required in addition to the hydrogen peroxide preparations already mentioned.

[0007] Bleaching hair with a dark base color presents a particular challenge. Natural hair color is determined by melamine in the cortex of the hair fiber, with the ratio of the two pigment classes, eumelanin with brownish-black tones and pheomelanin with reddish-orange tones, determining the actual hair color. Typically, the bleaching process destroys the natural melanin pigments through oxidative action, thus leading to decolorization of the fibers. However, due to the different oxidative destruction rates of the various melanin pigment classes, hair is not decolorized evenly. In darker fibers with a high melanin content, a certain amount of pigment usually remains, which is often reflected in reddish nuances. Therefore, a color shift towards warmer tones occurs, particularly when bleaching darker hair.Typically, such color shifts toward warmer tones are undesirable for the user. Therefore, this color shift is usually counteracted by tinting with the corresponding complementary color according to color theory. The goal is to achieve a silvery-cool impression of the bleaching result. In this context, experts refer to this as matting. Depending on the original hair color, an adapted tinting agent mixture must be used to compensate for redder color shifts caused by greener tinting agents. Direct dyes and pigments are used as tinting agents.

[0008] Under the aggressive conditions (strong oxidizing agents, high pH value) of the lightening preparation, the commonly used tinting agents are usually not sufficiently stable. Therefore, the bleaching and tinting steps usually have to be performed sequentially. For reasons of ease of use, however, a one-step bleaching process that already includes the matting color balance of unwanted warm tones is particularly advantageous. Therefore, there is a need for bleaching agents that achieve good color balance and thus a high level of matting even without the addition of tinting components to the application preparation.

[0009] In the course of its research, the applicant has now surprisingly discovered that pretreating the keratin fibers with a riboflavin derivative in combination with an alpha-hydroxycarboxylic acid and a selected polyol, followed by irradiation with blue light or UVB light, increases the lightening performance at the same oxidant concentration. The red shift of the bleaching result was also reduced.

[0010] State of the art

[0011] WO 2019 / 121941 A1 discloses a method in which keratin fibers, in particular human hair, are first treated with a flavin derivative, in particular riboflavin, and then irradiated with light having a wavelength in the range of 360 to 600 nm to condition the hair and repair hair damage. This document applies the teaching that riboflavin is suitable for cross-linking the protein collagen in the human cornea as a treatment for keratoconus to the cross-linking of the hair protein keratin. US2015 / 0224041 A1 and WO 2013 / 174871 A1 disclose a method for coloring hair with direct dyes or pigments, in which these are applied to the hair together with a photoactivator, such as riboflavin, and then irradiated. The direct dyes can be optical brighteners, so that the keratin fibers appear optically brightened.However, this process does not oxidatively break down the hair’s natural melanin pigments.

[0012] Task

[0013] The object of the present invention was to provide a method for the oxidative lightening of keratin-containing fibers, in particular human hair, with an improved lightening result. According to the invention, the term "lightening of keratin fibers" refers only to the lightening commonly referred to as bleaching, in which the keratin fibers are lightened and bleached by the oxidative destruction of the natural or artificial pigments, in particular the natural melanin pigments, but also artificial oxidation colorants. A purely optical lightening through the application of direct optical brighteners does not constitute lightening within the meaning of the present invention. An improved lightening result is understood according to the invention to mean that the achieved color tone has a higher L value in the colorimetric measured values ​​of the L ab color space.According to the invention, an improved lightening result also includes reducing the undesirable red tone that can arise during the oxidative degradation of natural melanin pigments. In the L ab color space, this corresponds to a lower a-value.

[0014] Riboflavin, riboflavin esters, the salts of riboflavin and the salts of riboflavin esters are not considered to be direct dyes or pigments according to the invention.

[0015] Surprisingly, it has been found that with the lightening methods and kits described in the patent claims using a combination of riboflavin, riboflavin esters, the salts of riboflavin or the salts of riboflavin esters, at least one alpha-hydroxycarboxylic acid and a selected polyol as a pretreatment before bleaching with an intermediate step of irradiation with light of the wavelength in the range from 400 to 460 nm or in the range from 280 to 315 nm (UVB) from a non-natural source, an improved lightening result is achieved according to the invention.

[0016] A first subject of the present invention is therefore a process for the oxidative lightening of keratin fibers, in particular human hair, which comprises the following process steps in the given order: i. Application of a composition R, which

[0017] - Water,

[0018] - Riboflavin or an ester or a salt of riboflavin, - furthermore at least one alpha-hydroxycarboxylic acid and

[0019] - at least one polyol selected from polyhydric C2 - C8 alkanols having 2 - 6 hydroxyl groups and polyethylene glycols having 3 - 20 ethylene oxide units, and mixtures thereof, onto the keratin fibers to be lightened, ii. allowing the composition R to act for a time of 1 to 60 minutes, iii. irradiating the moist keratin fibers with light having a wavelength in the range from 400 to 460 nm or in the range from 280 to 315 nm (UVB) from a non-natural source for a period of 30 to 600 seconds, iv. within 1 second to 30 minutes after completion of step iii. applying a bleaching composition L to the keratin fibers and allowing the composition L to act for a time of 5 to 60 minutes, v. rinsing the keratin fibers and vi. Optional drying of the keratin fibers, whereby no direct dyes or pigments are applied at any step of the process.Another object of the present invention is a kit for the oxidative lightening of keratin fibers, in particular human hair, comprising a composition R.

[0020] - Water,

[0021] - Riboflavin or an ester or salt of riboflavin,

[0022] - furthermore at least one alpha-hydroxycarboxylic acid and

[0023] - at least one polyol selected from polyhydric C2 - C8 alkanols having 2 - 6 hydroxyl groups and polyethylene glycols having 3 - 20 ethylene oxide units and mixtures thereof, an anhydrous oxidative hair treatment agent (B) comprising at least one oxidizing agent which is solid under normal conditions, and optionally an oxidizing composition (Ox) which, in each case based on its weight, contains 50 - 96% by weight, preferably 70 - 93% by weight, particularly preferably 80 - 90% by weight, of water and 0.5 - 20% by weight of hydrogen peroxide and furthermore at least one pH adjuster in an amount such that it has a pH in the range from 1.5 to 5.5, measured at 20°C.

[0024] A third object of the present invention is the use of a composition R which

[0025] - Water,

[0026] - Riboflavin or an ester or salt of riboflavin,

[0027] - furthermore at least one alpha-hydroxycarboxylic acid and

[0028] - at least one polyol selected from polyhydric C2 - C8 alkanols having 2 - 6 hydroxyl groups and polyethylene glycols having 3 - 20 ethylene oxide units and mixtures thereof, for enhancing the lightening effect of an oxidative lightening agent for keratinic fibers, in particular human hair, and / or for reducing the red shift during melanin degradation.

[0029] All information on the physical states of substances (solid, liquid, gaseous) in this application refers to standard conditions. "Standard conditions" for the purposes of this application are a temperature of 20°C and a pressure of 1013.25 mbar.

[0030] Exposure to blue light (wavelength range from 400 to 460 nm) or UVB radiation (280 to 315 nm) on the keratin fibers treated with riboflavin, alpha-hydroxycarboxylic acid and polyol

[0031] An essential step of the lightening processes according to the invention and preferred according to the invention is that, following the application and action of the composition R, which contains riboflavin or one of the riboflavin derivatives specified below in combination with at least one alpha-hydroxycarboxylic acid (AHA) and at least one selected polyol, the keratin fibers are irradiated with light having a wavelength in the range of 400 to 460 nm or in the range of 280 to 315 nm (UVB) from a non-natural source for a period of 30 to 600 seconds, preferably 1 to 8 minutes, extremely preferably 2 to 5 minutes. Riboflavin has an absorption maximum at 430 nm, and therefore a violet or blue light source is used to activate the riboflavin.

[0032] In the bleaching process preferred according to the invention, the keratin fibers to be treated are successively first treated with the aqueous riboflavin / AHA / polyol composition R, then irradiated as described above and treated with a bleaching composition L within 1 second to 30 minutes after completion of the irradiation, wherein the composition L remains on the keratin fibers for a period of 5 to 60 minutes and is then rinsed out with water, wherein no direct dyes or pigments are applied in any step of the process.

[0033] It is preferred that the keratin fibers are dried after the final rinsing step, preferably first with a towel, then if necessary with a hair dryer or a hair dryer hood, or left to air dry.

[0034] It is further preferred that the keratin fibers are dabbed with a cloth after allowing the composition R to act. Particularly preferably, the keratin fibers have a water content of 1-42 wt.%, preferably 3-30 wt.%, particularly preferably 5-25 wt.%, extremely preferably 8-15 wt.%, based on their weight, before irradiation.

[0035] Further lightening processes which are particularly preferred according to the invention are characterized in that the keratin fibers, after completion of process step vi., have a water content of 1-42% by weight, preferably 3-30% by weight, particularly preferably 5-25% by weight, extraordinarily preferably 8-15% by weight of water, in each case based on their weight.

[0036] The source of the radiation is artificial. The artificial radiation can be continuous or discontinuous. For the purposes of the present invention, the term "artificial light radiation" means light radiation that is different from natural daylight, i.e., light generated by the sun. In other words, natural daylight, i.e., light generated by the sun, is not artificial light radiation.

[0037] The term "natural light radiation" means radiation whose only source of light is daylight produced by the sun.

[0038] Preferably, the artificial light radiation used has an energy quantity per unit area of ​​up to or equal to 1 J / cm 2 , more preferably greater than 1 J / cm 2 , even more preferably in the range of 1,001 and 100 J / cm 2 , even more preferably in the range of 2 to 50 J / cm 2 , particularly preferably in the range of 3 to 10 J / cm 2 on.

[0039] Preferably, the artificial light radiation used has a luminous efficacy of 50 to 100 lm / W (lumens per watt), preferably 70 to 85 lm / W.

[0040] The artificial light radiation used preferably has a luminous flux of 3500 to 8000 lumens, more preferably 4000 to 6000 lumens. The artificial light radiation is preferably generated using a device selected from arc lamps such as xenon lamps and mercury lamps, fluorescent lamps, incandescent lamps such as halogen lamps, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), and lasers.

[0041] Examples include Golite BLU products from Philips, the Energylight HF 3319 / 01 lamp from Philips, the Dayvia White and Messa lamps from Solvital, the Lumino Plus lamp from Laanaform, the Medibeam lamp from Medibeam, the M-LED 01 lamp from Meimed, the Lifemax Light Pod lamp from Lifemax, the Lite-Pad lamp from Reicorp, the Omnilux Clear-U and New-U lamps from Omnilux, the 1000 W xenon arc lamp from Lot-Oriel and the Camag Box 3 (4x8 W) lamp from Camag.

[0042] Ingredients in the composition R

[0043] Preferred whitening methods and whitening kits according to the invention are characterized in that the composition R contains water in an amount of 30.0 - 97.0 wt.%, preferably 50.0 - 95.0 wt.%, particularly preferably 70.0 - 93.0 wt.%, extraordinarily preferably 80.0 - 91.0 wt.%, based on the weight of the composition R.

[0044] Further whitening methods and whitening kits preferred according to the invention are characterized in that the composition R contains at least one substance selected from riboflavin, riboflavin esters, the salts of riboflavin and the salts of riboflavin esters, in a total amount of 0.1 - 5 wt.%, preferably 0.2 - 3 wt.%, particularly preferably 0.5 - 1 wt.%, in each case based on the weight of the composition R.

[0045] Further lightening methods and lightening kits preferred according to the invention are characterized in that the at least one alpha-hydroxycarboxylic acid in the composition R is selected from citric acid, lactic acid, malic acid, glycolic acid, tartaric acid, gluconic acid, glutaric acid, galactaric acid, tartronic acid, mandelic acid, isocitric acid and mixtures of these acids, with citric acid, lactic acid, malic acid, gluconic acid, glycolic acid and tartaric acid being preferred.

[0046] Further lightening methods and lightening kits preferred according to the invention are characterized in that the at least one alpha-hydroxycarboxylic acid is contained in the composition R in a total amount of 0.1 - 10.0 wt.%, preferably 0.5 - 5.0 wt.%, particularly preferably 1.0 - 3.0 wt.%, in each case based on the weight of the composition R.

[0047] Further whitening methods and whitening kits preferred according to the invention are characterized in that the composition R has a pH of 1.5 to 8.0, preferably of 2.0 to 7.0, particularly preferably of 2.2 to 6.5, extraordinarily preferably of 3.0 to 5.5, in each case measured at 20°C.Further whitening methods and whitening kits preferred according to the invention are characterized in that the at least one polyol, selected from polyhydric C2 - C8 alkanols having 2 - 6 hydroxyl groups and polyethylene glycols having 3 - 20 ethylene oxide units and mixtures thereof, is selected from 3-methyl-1,3-butanediol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 1,2-propylene glycol, 1,3-propanediol, glycerin, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2,6-hexanetriol, 1 ,2-octanediol, 1,8-octanediol, dipropylene glycol, tripropylene glycol, diglycerin, triglycerin, PEG-3, PEG-4, PEG-6, PEG-7, PEG-8, PEG-9, PEG-10, PEG-12, PEG-14, PEG-16, PEG-18 and PEG-20, and mixtures of these polyols, with the branched polyols 3-methyl-1,3-butanediol, 2-methyl-1,3-propanediol and 2-methyl-2,4-pentanediol and mixtures of these branched polyols being preferred.

[0048] Further whitening processes and whitening kits preferred according to the invention are characterized in that the at least one polyol, selected from polyhydric C2 - C8 alkanols having 2 - 6 hydroxyl groups and polyethylene glycols having 3 - 20 ethylene oxide units and mixtures thereof, is present in a total amount of 0.05 - 20 wt.%, preferably 0.1 - 15 wt.%, particularly preferably 1.0 - 10.0 wt.%, extraordinarily preferably 3.0 - 5.0 wt.%, in each case based on the weight of the composition R.

[0049] Anhydrous oxidative hair treatment agent (B)

[0050] Lightening kits according to the invention are characterized in that, in addition to the composition R containing water, a riboflavin derivative according to the claims, at least one alpha-hydroxycarboxylic acid and at least one selected polyol according to the claims, they further comprise an anhydrous oxidative hair treatment agent (B) containing at least one oxidizing agent which is solid under normal conditions.

[0051] Preferably, the at least one oxidizing agent which is solid under normal conditions is selected from the inorganic salts of a peroxosulfuric acid, mixtures of these salts, sodium percarbonate, sodium percarbamide, sodium perborate and mixtures of at least one salt of a peroxosulfuric acid and an oxidizing agent selected from sodium percarbonate, sodium percarbamide, sodium perborate and mixtures thereof.

[0052] Peroxosulfuric acids include peroxodisulfuric acid and peroxomonosulfuric acid (Caro's acid).

[0053] According to the invention, the at least one inorganic salt of a peroxosulfuric acid is preferably selected from ammonium peroxodisulfate, ammonium peroxomonosulfate, alkali metal peroxodisulfates, alkali metal peroxomonosulfates, and alkali metal hydrogen peroxomonosulfates. Particular preference is given to potassium peroxodisulfate, sodium peroxodisulfate, ammonium peroxodisulfate, and potassium hydrogen peroxomonosulfate, as well as mixtures thereof. Furthermore, it has proven particularly preferred in the work on the present invention if the anhydrous oxidative hair treatment agent (B) according to the invention contains at least two different peroxodisulfates. Preferred peroxodisulfate salts are potassium peroxodisulfate-ammonium peroxodisulfate mixtures, potassium peroxodisulfate-ammonium peroxodisulfate-sodium peroxodisulfate mixtures, and potassium peroxodisulfate-sodium peroxodisulfate mixtures.Particularly preferred are mixtures of potassium peroxodisulfate and ammonium peroxodisulfate, and extremely preferred are mixtures of potassium peroxodisulfate and ammonium peroxodisulfate with an excess of potassium peroxodisulfate, which are free of sodium peroxodisulfate. Particularly preferred mixtures of potassium peroxodisulfate (KPS) and ammonium peroxodisulfate (APS) according to the invention, which are free of sodium peroxodisulfate, are those with a KPS / APS weight ratio in the range of 4:1-2:1, preferably 3.5:1-2.5:1, particularly preferably 3.2:1-2.8:1.

[0054] Preferred anhydrous oxidative hair treatment agents (B) according to the invention contain at least one oxidizing agent selected from inorganic salts of a peroxosulfuric acid and mixtures thereof, in a total amount of 5-85% by weight, preferably 10-70% by weight, particularly preferably 17-55% by weight, extraordinarily preferably 22-45% by weight, in each case based on the weight of the oxidative hair treatment agent (B).

[0055] The oxidative hair treatment agents (B) according to the invention are anhydrous, which in the sense of the present invention means that they contain, in each case based on their weight, 0 to 12 wt.%, preferably 0.1 to 10 wt.%, particularly preferably 0.5 to 9 wt.% of water.

[0056] This information refers to the free water content. The content of molecularly bound water or water of crystallization, which individual powder components may contain, is not taken into account. The water content can be determined, for example, using Karl Fischer titration based on ISO 4317 (version 2011-12).

[0057] Alkalizing agent

[0058] For the melanin-degrading effect of the hydrogen peroxide and the bleaching effect on the keratin fiber, it is advantageous if the application mixture of hydrogen peroxide solution and persalt-containing oxidative hair treatment agent (B) has an alkaline pH value which is in the range from 8.0 to 11.5, preferably in the range from 8.5 to 11.0, particularly preferably 9.0 - 10.5, extremely preferably 9.5 - 10.3, in each case measured at 20°C.

[0059] To establish an alkaline pH of the lightening bleaching composition L, preferred oxidative hair treatment agents (B) according to the invention can contain, in addition to the at least one persalt that is solid under normal conditions, at least one alkalizing agent that is solid under normal conditions in a total amount such that the bleaching composition L has the desired alkaline pH. Alternatively, a further composition (Alk) can be added to the application mixture of oxidative hair treatment agent (B) according to the invention and hydrogen peroxide solution (Ox), which further composition contains one or more alkalizing agents in an amount such that the application mixture has an alkaline pH that is in the range from 8.0 to 11.5, preferably in the range from 8.5 to 11.0, particularly preferably 9.0 - 10.5, extraordinarily preferably 9.5 - 10.3, in each case measured at 20°C.

[0060] Oxidative hair treatment agents (B) preferred according to the invention are therefore characterized by containing at least one inorganic alkalizing agent that is solid at 20°C and 1013 mbar. Particularly preferred oxidative hair treatment agents (B) according to the invention contain at least one inorganic alkalizing agent that is solid at 20°C and 1013 mbar in a total amount of 4-70 wt.%, preferably 10-65 wt.%, particularly preferably 15-60 wt.%, extremely preferably 20-55 wt.%, in each case based on the weight of the oxidative hair treatment agent (B).

[0061] Further oxidative hair treatment agents (B) preferred according to the invention contain at least one inorganic alkalizing agent which is solid at 20 °C and 1013 mbar, including, in a total amount of 0.1 to 50 wt. %, preferably 4 to 30 wt. %, particularly preferably 15-25 wt. %, in each case based on the weight of the oxidative hair treatment agent, at least one sodium silicate or sodium metasilicate having a molar SiO2 / Na2O ratio of > 2, preferably 2.5-3.5.

[0062] In addition to the at least one sodium silicate or sodium metasilicate with a molar SiO2 / Na2O ratio of > 2, preferably 2.5-3.5, in a total amount of 0.1-50 wt.%, preferably 4-30 wt.%, particularly preferably 15-25 wt.%, in each case based on the weight of the oxidative hair treatment agent (B), as optional alkalizing agent, further inorganic alkalizing agents which are particularly preferred according to the invention and are solid at 20 °C and 1013 mbar are selected from alkaline earth metal silicates, alkaline earth metal hydroxide carbonates, alkaline earth metal carbonates, alkaline earth metal metasilicates, alkali metal hydroxides, alkaline earth metal hydroxides, (alkali) earth metal phosphates and (alkali) earth metal hydrogen phosphates and mixtures of these substances.Particularly preferred inorganic alkalizing agents according to the invention, which are solid at 20°C and 1013 mbar, are, in addition to the at least one obligatory sodium silicate or sodium metasilicate, each with a molar SiO2 / Na2O ratio of > 2, preferably from 2.5 to 3.5, selected from magnesium hydroxide carbonates and mixtures of these alkalizing agents. Magnesium hydroxide carbonates preferred according to the invention are those with the formula MgCOs ■ Mg(OH)2 ■ 2 H2O and those with the formula MgCOs ■ Mg(OH)2. Magnesium hydroxide carbonate with the formula MgCOs ■ Mg(OH)2 is particularly preferred according to the invention.

[0063] Particularly preferred oxidative hair treatment agents (B) according to the invention contain, in each case based on their total weight, 0.1 to 50 wt.%, preferably 4 - 30 wt.%, particularly preferably 15 - 25 wt.%, of sodium silicates with a molar SiO2 / Na2O ratio of > 2, preferably from 2.5 to 3.5, and 2 - 40 wt.%, preferably 5 - 35 wt.%, particularly preferably 10 - 32 wt.% of magnesium hydroxide carbonate as inorganic alkalizing agents which are solid at 20 °C and 1013 mbar.

[0064] Depending on the type of oxidizing agent which is solid under normal conditions and which is contained in the anhydrous oxidative hair treatment agent (B), the lightening process according to the invention or the lightening kits according to the invention use either an oxidizing composition (Ox) which, in each case based on its weight, contains 50 - 96% by weight, preferably 70 - 93% by weight, particularly preferably 80 - 90% by weight, water and 0.5 - 20% by weight of hydrogen peroxide and furthermore at least one pH adjuster in an amount such that it has a pH in the range from 1.5 to 5.5, measured at 20°C, or oxidizing agent-free water.A first preferred method for the oxidative lightening of keratin fibers, in particular human hair, is therefore characterized in that the bleaching composition L is prepared immediately before its application to the keratin-containing fibers by mixing an anhydrous oxidative hair treatment agent (B) containing at least one oxidizing agent which is solid under normal conditions and is selected from the inorganic salts of a peroxosulfuric acid, and mixtures of these salts, with an oxidizing composition (Ox) which, in each case based on its weight, contains 50-96% by weight, preferably 70-93% by weight, particularly preferably 80-90% by weight, of water and 0.5-20% by weight of hydrogen peroxide and further contains at least one pH adjuster in an amount such that the oxidizing composition has a pH in the range from 1.5 to 5.5, measured at 20°C.

[0065] Likewise, a first preferred kit for the oxidative lightening of keratin fibers, in particular human hair, is characterized in that it comprises a composition R containing

[0066] - Water,

[0067] - Riboflavin or an ester or salt of riboflavin,

[0068] - furthermore at least one alpha-hydroxycarboxylic acid and

[0069] - at least one polyol selected from polyhydric C2 - C8 alkanols having 2 - 6 hydroxyl groups and polyethylene glycols having 3 - 20 ethylene oxide units, and mixtures thereof, furthermore an anhydrous oxidative hair treatment agent (B) containing at least one oxidizing agent which is solid under normal conditions and is selected from the inorganic salts of a peroxosulfuric acid, and mixtures of these salts, and an oxidation composition (Ox) which, in each case based on its weight, 50 - 96% by weight, preferably 70 - 93% by weight, particularly preferably 80 - 90% by weight, of water and 0.5 - 20% by weight of hydrogen peroxide and furthermore at least one pH adjuster in an amount such that it has a pH in the range from 1.5 to 5.5, measured at 20°C.

[0070] Another preferred method for the oxidative lightening of keratin fibers, in particular human hair, is characterized in that the bleaching composition L is prepared immediately before its application to the keratin-containing fibers by mixing an anhydrous oxidative hair treatment agent (B) containing at least one oxidizing agent which is solid under normal conditions and is selected from sodium percarbonate, sodium percarbamide and sodium perborate and mixtures thereof, with oxidizing agent-free water.

[0071] Another preferred kit for the oxidative lightening of keratin fibers, in particular human hair, is characterized in that it comprises a composition R containing

[0072] - Water,

[0073] - Riboflavin or an ester or a salt of riboflavin, - furthermore at least one alpha-hydroxycarboxylic acid and

[0074] - at least one polyol selected from polyhydric C2-C8 alkanols having 2-6 hydroxyl groups and polyethylene glycols having 3-20 ethylene oxide units, as well as mixtures thereof, and further comprising an anhydrous oxidative hair treatment agent (B) containing at least one oxidizing agent that is solid under normal conditions and selected from sodium percarbonate, sodium percarbamide, and sodium perborate, as well as mixtures thereof. In this case, the oxidizing agent-free water sufficient to activate sodium percarbonate, sodium percarbamide, and sodium perborate is not provided in separate packaging, but can be provided by the user at the time of application, preferably as tap water from a faucet.

[0075] With regard to further preferred embodiments of the kits and uses according to the invention, what has been said regarding the bleaching methods according to the invention applies mutatis mutandis.

[0076] To optimize the applicability of composition R and its retention time on the keratin fibers, it is preferred that the composition R has a thickened consistency. Preferably, compositions R are in the form of a gel, cream, or paste. Such carriers ensure a homogeneous distribution and a sufficient retention time of the composition R on the keratin fibers.

[0077] The compositions R used according to the invention and preferably according to the invention may optionally contain further additives to optimize the application properties of these compositions. Preferred additives are, in particular, thickeners, which ensure that the composition R adheres better to the hair during application.

[0078] Compositions R used with particular preference according to the invention contain at least one or more hydrophilic thickeners, which are preferably selected from polysaccharides that may be chemically and / or physically modified. Compounds from the group of polysaccharides are particularly preferred as hydrophilic thickeners according to the invention, since the basic structures of the polysaccharides are of natural origin and biodegradable. Preferred hydrophilic polysaccharide thickeners are selected from celluloses, cellulose ethers of C1-C4 alcohols, cellulose esters, xanthan gum, alginic acids (and their corresponding physiologically acceptable salts, the alginates), agar agar (with the polysaccharide agarose present in agar agar as the main constituent), starch fractions and starch derivatives such as amylose, amylopectin and dextrins, karaya gum, locust bean gum, gum arabic, pectins, dextrans and guar gum, and mixtures thereof.Cellulose ethers of C1-C4 alcohols and cellulose esters preferred according to the invention are selected from methylcelluloses, ethylcelluloses, hydroxyalkylcelluloses (such as hydroxyethylcellulose), methylhydroxyalkylcelluloses and carboxymethylcelluloses (such as those with the INCI name Cellulose Gum) and their physiologically acceptable salts.

[0079] In preferred embodiments, xanthan gum is included as a hydrophilic thickener for reliable viscosity adjustment and residue-free application to keratin fibers and the scalp. In further preferred embodiments, carboxymethylcellulose (preferably sodium carboxymethylcellulose with the INCI name Cellulose Gum) is included as a hydrophilic thickener for reliable viscosity adjustment and residue-free application to keratin fibers and the scalp. In a preferred embodiment, carboxymethylcellulose can be included as the sole hydrophilic thickener. A combination of sodium carboxymethylcellulose and hydroxyethylcellulose is particularly preferred. The combination of sodium carboxymethylcellulose and xanthan gum can also be preferred according to the invention.

[0080] Compositions R used with particular preference according to the invention contain at least one hydrophilic thickener in a total amount of 0.1 to 5% by weight, preferably 0.5 to 4% by weight, more preferably 1 to 3.5% by weight and most preferably 1.2 to 2% by weight, in each case based on the weight of the composition R.

[0081] Compositions R which are particularly preferably used according to the invention contain at least one oil. Preferred cosmetic oils are selected from natural and synthetic hydrocarbons, particularly preferably from paraffin oils, C1a-C10-isoparaffins, in particular isoeicosane, polyisobutenes and polydecenes, Cs-C1e-isoparaffins, and also 1,3-di-(2-ethylhexyl)-cyclohexane; the benzoic acid esters of linear or branched Cs-22-alkanols; fatty alcohols having 6-30 carbon atoms which are unsaturated or branched and saturated or branched and unsaturated; triglycerides of linear or branched, saturated or unsaturated, optionally hydroxylated Cs-10-fatty acids, in particular natural oils; the dicarboxylic acid esters of linear or branched C2-C10-alkanols;the esters of linear or branched saturated or unsaturated fatty alcohols with 2 - 30 carbon atoms with linear or branched saturated or unsaturated fatty acids with 2 - 30 carbon atoms, which may be hydroxylated; the addition products of 1 to 5 propylene oxide units with mono- or polyhydric C8-22 alkanols; the addition products of at least 6 ethylene oxide and / or propylene oxide units with mono- or polyhydric C8-22 alkanols; the C8-C22 fatty alcohol esters of monohydric or polyhydric C2-C7 hydroxycarboxylic acids; the symmetrical, asymmetrical or cyclic esters of carbonic acid with C8-22 alkanols, C8-22 alkanediols or C8-22 alkanetriols; the esters of dimers of unsaturated C12-C22 fatty acids (dimer fatty acids) with monohydric linear, branched, or cyclic C2-C18 alkanols or with polyhydric linear or branched C2-C18 alkanols; silicone oils, and mixtures of the aforementioned substances.

[0082] Further compositions R used particularly preferably according to the invention contain at least one surfactant or one emulsifier.

[0083] Surfactants and emulsifiers within the meaning of the present application are amphiphilic (bifunctional) compounds consisting of at least one hydrophobic and at least one hydrophilic molecular moiety. The hydrophobic radical is preferably a hydrocarbon chain having 8-28 carbon atoms, which may be saturated or unsaturated, linear or branched. This C8-028 alkyl chain is particularly preferably linear. Basic properties of the surfactants and emulsifiers are oriented absorption at interfaces, aggregation into micelles, and the formation of lyotropic phases. When selecting surfactants suitable according to the invention, it may be preferable to use a mixture of surfactants in order to optimally adjust the stability of the compositions R used according to the invention. Preferred surfactants and emulsifiers are selected from anionic, cationic, zwitterionic, amphoteric, and nonionic surfactants and emulsifiers, as well as mixtures of these substances.

[0084] The keratin fibers are preferably dried after rinsing out composition L. Drying can be carried out without actively applying heat. However, drying can also be carried out with the application of heat at a temperature of 25–120°C, particularly preferably at a temperature of 30–80°C, and extremely preferably at a temperature of 35–60°C. Heat is preferably applied using a heat lamp, a drying rod, a hair dryer, a straightening iron, or a hair dryer.

[0085] The keratin fibers can be dried with an absorbent cloth, such as a towel. Towel-dried hair can optionally be partially or completely dried with a hairdryer or other heat source. It is also possible to let the keratin fibers air dry.

[0086] Compositions R used with exceptional preference according to the invention are characterized in that they contain at least one fragrance in a total amount of 0.01 - 5% by weight, preferably 0.1 - 3% by weight, particularly preferably 0.5 - 2% by weight, exceptionally preferably 1 - 1.5% by weight, in each case based on the weight of the composition R.

[0087] Implementation examples

[0088] The exemplary embodiments presented below are intended to explain the subject matter of the invention in more detail without limiting it thereto.

[0089] The lightening process according to the invention was carried out on Kerling brand hair strands, shade 4-0. Composition R used according to the invention was a 1 wt.% aqueous solution of riboflavin 5'monophosphate sodium salt in water, which also contained 3 wt.% citric acid monohydrate and 5 wt.% of the polyol 3-methyl-1,3-butanediol.

[0090] Table 1 : Composition R (pH of the composition: 2.2 (measured at 20°C)) The Kerling strands were immersed in this solution for 60 minutes while stirring. The liquor ratio was 2 grams of hair to 8 grams of composition R.

[0091] After completion of the treatment with composition R, the hair strands were squeezed and then irradiated with blue light of wavelength 450 nm for 5 minutes.

[0092] In the subsequent step of the lightening process according to the invention, the strands were treated with a lightening composition L, which was prepared from 1 part by weight of oxidative hair treatment agent (B) (see Table 2) and 2 parts by weight of oxidation composition (Ox) (see Table 3) by mixing (B) and (Ox) immediately before application to the test strands. After a 45-minute exposure time, the agent L was rinsed out of the hair, washed and dried, and colorimetrically analyzed.

[0093] Table 2: Bleaching powder (oxidative hair treatment agent B)

[0094] Table 3: Oxidant-containing developer (Ox) for bleaching powder from Table 2

[0095] Determination of the color shade achieved by the process according to the invention

[0096] All colorimetric measurements were performed using the Spectraflash SF 600 colorimetric device from Datacolor.

[0097] The color difference, also known as dE or AE, can be easily determined colorimetrically using a colorimeter that measures colors in the L*, a*, b* color space, for example a Datacolor Spectraflash SF 600 colorimeter.

[0098] The L*,a*,b* color space refers to the CIELAB color space. The L value represents the brightness of the color (black-white axis); the higher the L value, the brighter the color. The a value represents the red-green axis of the system; the higher this value, the more the color is shifted toward red. The b value represents the yellow-blue axis of the system; the higher this value, the more the color is shifted toward yellow.

[0099] The color shift AE, i.e. the color difference between two (hair) colors, for each of which an L*, a*, b* value combination has been determined, is calculated according to the following formula:

[0100] AE = (AL 2 + Aa 2 + From 2 ) 05

[0101] The larger the value for AE, the more pronounced the color difference.

[0102] A D65 illuminant and a diffuse / 8° optical configuration were used for the spectrophotometer measurements. The spectral reflectance data for each sample from 380 nm to 700 nm were converted to colorimetric data using DCI Color software. Reflectance measurements were determined for each hair sample, with the average of four measurements recorded.

[0103] The color difference (AE) between the uncolored strand and the colored strand was calculated according to the following formula:

[0104] Lv, av, bv: Colorimetric values ​​for treated strand

[0105] Ln, an, bn: Colorimetric values ​​for unbleached, untreated strands Table 4: Results of the colorimetric measurements

[0106]

Claims

Patent claims 1. A process for the oxidative lightening of keratin fibres, in particular human hair, comprising the following process steps in the order given: i. Application of a composition R which - Water, - Riboflavin or an ester or a salt of riboflavin, - furthermore at least one alpha-hydroxycarboxylic acid and - at least one polyol selected from polyhydric C2 - C8 alkanols having 2 - 6 hydroxyl groups and polyethylene glycols having 3 - 20 ethylene oxide units, and mixtures thereof, onto the keratin fibers to be lightened, ii. allowing the composition R to act for a time of 1 to 60 minutes, iii. irradiating the moist keratin fibers with light having a wavelength in the range from 400 to 460 nm or in the range from 280 to 315 nm (UVB) from a non-natural source for a period of 30 to 600 seconds, iv. within 1 second to 30 minutes after completion of step iii. applying a bleaching composition L to the keratin fibers and allowing the composition L to act for a time of 5 to 60 minutes, v. rinsing the keratin fibers and vi. Optional drying of the keratin fibers, whereby no direct dyes or pigments are applied at any step of the process.

2. A process for the oxidative lightening of keratinous fibers, in particular human hair, according to claim 1, characterized in that the bleaching composition L is prepared immediately before its application to the keratin-containing fibers by mixing an anhydrous oxidative hair treatment agent (B) containing at least one oxidizing agent which is solid under normal conditions and is selected from the inorganic salts of a peroxosulfuric acid, and mixtures of these salts, with an oxidizing composition (Ox) which, in each case based on its weight, contains 50-96% by weight, preferably 70-93% by weight, particularly preferably 80-90% by weight, of water and 0.5-20% by weight of hydrogen peroxide and further contains at least one pH adjuster in an amount such that the oxidizing composition has a pH in the range from 1.5 to 5.5, measured at 20°C.

3. A process for the oxidative lightening of keratinous fibers, in particular human hair, according to claim 1, characterized in that the bleaching composition L is prepared immediately before its application to the keratin-containing fibers by mixing an anhydrous oxidative hair treatment agent (B) containing at least one under normal conditions, solid oxidizing agent selected from sodium percarbonate, sodium percarbamide and sodium perborate and mixtures thereof, with oxidizing agent-free water.

4. Process according to one of claims 1-3, characterized in that the composition R contains water in an amount of 30.0-97.0 wt.%, preferably 50.0-95.0 wt.%, particularly preferably 70.0-93.0 wt.%, extraordinarily preferably 80.0-91.0 wt.%, based on the weight of the composition R.

5. The method according to any one of claims 1 to 4, characterized in that the composition R contains the at least one substance selected from riboflavin, riboflavin esters, the salts of riboflavin and the salts of riboflavin esters, in a total amount of 0.1 - 5 wt.%, preferably 0.2 - 3 wt.%, particularly preferably 0.5 - 1 wt.%, in each case based on the weight of the composition R.

6. The method according to any one of claims 1-5, characterized in that the at least one alpha-hydroxycarboxylic acid in the composition R is selected from citric acid, lactic acid, malic acid, glycolic acid, tartaric acid, gluconic acid, glutaric acid, galactaric acid, tartronic acid, mandelic acid, isocitric acid and mixtures of these acids, with citric acid, lactic acid, malic acid, gluconic acid, glycolic acid and tartaric acid being preferred.

7. Process according to one of claims 1-6, characterized in that the composition R contains the at least one alpha-hydroxycarboxylic acid in a total amount of 0.1-10.0% by weight, preferably 0.5-5.0% by weight, particularly preferably 1.0-3.0% by weight, in each case based on the weight of the composition R.

8. Process according to one of claims 1-7, characterized in that the composition R has a pH of 1.5 to 8.0, preferably of 2.0 to 7.0, particularly preferably of 2.2 to 6.5, extraordinarily preferably of 3.0 to 5.5, in each case measured at 20°C.

9. The method according to any one of claims 1-8, characterized in that the at least one polyol selected from polyhydric C2-C8 alkanols having 2-6 hydroxyl groups and polyethylene glycols having 3-20 ethylene oxide units and mixtures thereof is selected from 3-methyl-1,3-butanediol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 1,2-propylene glycol, 1,3-propanediol, glycerol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2,6-hexanetriol, 1,2-octanediol, 1,8-octanediol, dipropylene glycol, tripropylene glycol, diglycerin, triglycerin, PEG-3, PEG-4, PEG-6, PEG-7, PEG-8, PEG-9, PEG-10, PEG-12, PEG-14, PEG-16, PEG-18 and PEG-20, as well as mixtures of these polyols, wherein the branched polyols are 3-methyl-1,3-butanediol, 2-methyl-1,3-propane- diol and 2-methyl-2,4-pentanediol and mixtures of these branched polyols are preferred.

10. The method according to any one of claims 1-9, characterized in that the at least one polyol selected from polyhydric C2-C8 alkanols having 2-6 hydroxyl groups and polyethylene glycols having 3-20 ethylene oxide units and mixtures thereof is present in a total amount of 0.05-20 wt.%, preferably 0.1-15 wt.%, particularly preferably 1.0-10.0 wt.%, extraordinarily preferably 3.0-5.0 wt.%, in each case based on the weight of the composition R.

11. Kit for the oxidative lightening of keratin fibers, in particular human hair, comprising a composition R containing - Water, - Riboflavin or an ester or a salt of riboflavin, - furthermore at least one alpha-hydroxycarboxylic acid and - at least one polyol selected from polyhydric C2 - C8 alkanols having 2 - 6 hydroxyl groups and polyethylene glycols having 3 - 20 ethylene oxide units and mixtures thereof, an anhydrous oxidative hair treatment agent (B) comprising at least one oxidizing agent which is solid under normal conditions, and optionally an oxidizing composition (Ox) which, in each case based on its weight, contains 50 - 96% by weight, preferably 70 - 93% by weight, particularly preferably 80 - 90% by weight, of water and 0.5 - 20% by weight of hydrogen peroxide and furthermore at least one pH adjuster in an amount such that it has a pH in the range from 1.5 to 5.5, measured at 20°C.

12. Kit for oxidative lightening according to claim 11, characterized in that the oxidizing agent which is solid under normal conditions and which is contained in the anhydrous oxidative hair treatment agent (B) is selected from the inorganic salts of a peroxosulfuric acid, as well as mixtures of these salts and the oxidizing composition (Ox) is necessarily included.

13. Kit for oxidative lightening according to claim 11, characterized in that the at least one oxidizing agent which is solid under normal conditions and which is contained in the anhydrous oxidative hair treatment agent (B) is selected from sodium percarbonate, sodium percarbamide and sodium perborate and mixtures thereof, and no oxidizing composition (Ox) is included.

14. Use of a composition R which - Water, - Riboflavin or an ester or salt of riboflavin, - furthermore at least one alpha-hydroxycarboxylic acid and - at least one polyol selected from polyhydric C2 - C8 alkanols having 2 - 6 hydroxyl groups and polyethylene glycols having 3 - 20 ethylene oxide units and mixtures thereof, for enhancing the lightening effect of an oxidative lightening agent for keratinic fibers, in particular human hair, and / or for reducing the red shift during melanin degradation.

15. Use according to claim 14 or kit according to claim 11, characterized in that the composition R is as in any one of claims 4 to 10.

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