[0001] [The present invention is related to the products for dyeing/bleaching hair, and more specifically it concerns a new method for dyeing/bleaching hair and for treating hair in general by using a coloured hydrogen peroxide solution hereinafter referred to as coloured oxidizing solution.

[0002] The patent concerns also a new oxidizing solution for dyeing/bleaching hair and for hair treatments in general, and a new mixture in two phases for dyeing/bleaching hair and for hair treatments in general.

[0003] 1 . PERMANENT CHANGE OF HAIR COLOUR

[0004] It is known that in hair bleaching and dyeing processes it is necessary, from a chemical point of view, to use a hydrogen peroxide solution combined with other products and to use different techniques for the purpose of changing the hair colour, be it natural or artificial.

[0005] According to official statistics, hair dyes are used by more than 60% of the female population and by 5-10% of the male population for different purposes such as for covering grey hair or for changing the natural or artificial colour of the hair.

[0006] The average frequency with which people bleach and/or dye their hair is 6/8 times per year.

[0007] The natural colour of hair is determined by melanin, a polymer with high molecular weight, insoluble in water and in many solvents, with very low chemical reactivity. Melanin is present in dark hair in the form of larger or smaller granules and in blond-red hair in the form of micro granules.

[0008] 1 .a CHEMICAL DYEING

[0009] The artificial dye which is most resistant to deterioration and change over time is the permanent dye resulting from oxidation, the so-called oxidative dye due to the type of chemical reaction involved. The hair dyeing mechanism is complicated and involves the use of precursors, that is, of uncolored chemical substances which during the oxidative polycondensation process are capable of producing, through oxidation, a polymer pigment that adheres to keratin.

[0010] For example, on the occasion of the "CIR Expert Panel Meeting December 4, 2017", Carsten Goebel, Ph. D. Cosmetic Europe Hair Colorant Product Safety, in his presentation "Chemistry of Hair Coloring" described an oxidation chemical reaction (Chemistry of Oxidative Coupling Reaction) in which molecules suited to produce a condensation reaction in the presence of hydrogen peroxide combine producing the dyeing of the hair.

[0011] The diagram below exemplifies the process.

[0012] Reaction speed. Oxidation reaction k1 < Condensation reaction k2 «

Oxidation reaction k3.

[0013] The resulting colour depends on the combination of the precursors used.

[0014] Various types of hair dyes are known in the market, all of which consist of two separate phases: a first phase containing the dye precursors and a second phase containing the oxidants, that is, a hydrogen peroxide solution.

[0015] The two phases must be mixed together at the moment of application to the hair.

[0016] Some examples of precursors capable of oxidizing in the presence of hydrogen peroxide are illustrated below.

[0017] Here below, instead, are some examples of couplers, that is, molecules which can react (through condensation) with the oxidized precursors to produce the polymer pigment.

[0018] 1 .b BLEACHING

[0019] Hair bleaching is a chemical treatment suited to remove from the hair the colouring substances which can be of natural origin, like melanin, or of artificial origin, that is, deriving from previous oxidative dyeing treatments.

[0020] Bleaching agents generally contain peroxide salts: ammonium persulfate, sodium persulfate, potassium persulfate and the like. When said peroxide salts are mixed with water or with aqueous hydrogen peroxide solutions, they develop a high concentration of oxidants and a high pH, generally higher than 9 and more often included between 10 and 11 , generally due to the presence of sodium metasilicate.

[0021] Below is the formula of a hydrolysis reaction of ammonium peroxydisulfate producing hydrogen peroxide:

[0022] (NH4)2S ₂ 0 ₈ + 2 H2O ® 2 (NH ) HS0 ₄ + H2O2

[0023] Artificial hair bleaching is therefore an intense oxidation process in concentrated alkaline solutions.

[0024] The degradation of eumelanin and pheomelanin, which are sub-components of melanin, in a basic environment and in the presence of hydrogen peroxide is a known process, even if not completely characterized. [0025] The process of degradation of the natural hair colour takes place also during a normal oxidation dyeing process and the greater the quantity of hydrogen peroxide in the solution, the more evident the lightening effects deriving from the oxidation dyeing process.

[0026] According to the regulations currently in force in the EU, the maximum concentration of hydrogen peroxide allowed for hair products is equal to 12%.

[0027] In oxidation dyeing processes, the use of dyes that are different from the products with precursors and couplers is also known, in particular direct dyes, which are used to improve the hair colour tone obtained through oxidation processes.

[0028] Said direct dyes, which are included in the same phase containing the precursors, generally belong to the families described below.

Disperse Black 9 Disperse Viofet 1

[0029] Said dyes do not participate in the oxidative condensation reactions but affect the final colour of the hair.

[0030] Said dyes cannot be added to the phase containing the oxidants as they are not stable and are quickly affected by the oxidizing action, thus reducing the effectiveness of the product.

[0031] Dyes which are stable in hydrogen peroxide are known but their use in hair products in combination with the oxidizing agent is forbidden.

[0032] The subject of the present invention is a new method for dyeing/bleaching and for treating hair in general by means of a coloured hydrogen peroxide solution, hereinafter referred to as coloured oxidizing solution, that is, a solution containing hydrogen peroxide and at least one dye belonging to at least one class of polymer azo dyes.

[0033] The patent concerns also the new oxidizing solution for hair dyeing/bleaching and for hair treatments in general as well as a new mixture in two phases for hair dyeing/bleaching and for hair treatments in general, wherein the first phase comprises said oxidizing solution and the second phase comprises the precursors, and wherein said two phases must be mixed together at the moment of application to the hair.

[0034] The dye differs both from direct dyes and from the precursors currently used in hair dyeing/bleaching products, being a polymer dye which does not react with hydrogen peroxide, and therefore can be included in the oxidizing solution, which in fact contains hydrogen peroxide, and remain stable.

[0035] An example of a polymer dye used and having specific proven effectiveness is the dye classified with the following INCI name: Bis-Hydroxyethyl/PPG-7/PEG-4 Dicyanomethylthiophene Azotoluidine. The specified INCI name describes a compound containing the dyeing pigment and substances with stabilizing and preserving properties.

[0036] More specifically, said coloured oxidizing solution can be used in hair bleaching and/or dyeing treatments.

[0037] The dye, therefore, is not included in the phase containing the precursor but rather in the phase containing hydrogen peroxide.

[0038] The present invention ensures more versatility of use since the implementation of the new method makes it possible to change the colour hue through several techniques and products used in combination with them.

[0039] For example, said coloured oxidizing solution can be mixed with other compounds in turn containing the precursor and the couplers normally used in oxidation dyeing processes.

[0040] Said coloured oxidizing solution comprises a concentration of hydrogen peroxide which is variable and in any case within the limit value established by the regulations in force, currently 12%. [0041] Said coloured oxidizing solution can be used in combination with bleaching compounds in the form of powder, cream, or oil.

[0042] Said coloured oxidizing solution, furthermore, can also be used alone on the hair for post-straightening or post-waving fixing treatments with a neutralizing/toning effect, to fix the hair style and/or to counteract the yellow hues of the hair.

[0043] The effectiveness of the coloured oxidizing solution and its versatility have been verified through experimental applications, wherein said coloured oxidizing solution has been used in combination with several compounds to carry out hair bleaching and dyeing tests.

[0044] The tests carried out are described below.

[0045] OBJECT OF THE TEST

[0046] The object of the test is to assess the neutralizing effectiveness of the dyeing pigment contained in the coloured oxidizing solution on a hair lock. Neutralizing effectiveness generically means the ability to mitigate some undesired hues which emerge during the hair bleaching and/or dyeing operations and tend to produce a colour change towards yellow and reddish tones, which generally takes place in the case of very dark hair.

[0047] Said test is carried out by varying the concentration of dyeing pigment and hydrogen peroxide in the coloured oxidizing solution.

[0048] TESTED SAMPLES:

[0049] Sample 1

[0050] Name: STD oxygen 20 Vol.

[0051] where STD oxygen indicates a water-based stabilized oxidizing emulsion containing emulsifiers and waxes of plant origin, with viscosity included between 900 and 1200 cps.

[0052] This emulsion has been tested with three different concentrations of dyeing pigment: A=0.005 %, B=0.01 %, C=0.1 %.

[0053] Sample 2

[0054] Name: STD oxygen 40 Vol. [0055] This emulsion has been tested with three different concentrations of dyeing pigment: A=0.005 %, B=0.01 %, C=0.1 %.

[0056] Sample 3

[0057] Name: Coactivator 20 Vol.

[0058] where Coactivator indicates a water-based stabilized emulsion containing emulsifiers and waxes of plant origin, with viscosity included between 8000 and 120000 cps.

[0059] This emulsion has been tested with three different concentrations of dyeing pigment: A=0.005 %, B=0.01 %, C=0.01 %.

[0060] Sample 4

[0061] Name: Coactivator 40 Vol.

[0062] This emulsion has been tested with three different concentrations of dyeing pigment: A=0.005 %, B= 0.01 %, C= 0.01 %.

[0063] The dye mentioned above, whose INCI name is Bis-Hydroxyethyl/PPG-7/PEG- 4 Dicyanomethylthiophene Azotoluidine, is used in all samples.

[0064] TEST PROTOCOL

[0065] Test 1 : BLEACHING

[0066] Each sample has been mixed with a bleaching powder in the ratio 1 :2 (powdersample), applied to a hair lock in a natural colour (tone 6 - dark blond) and left on for 45 minutes.

[0067] Test 2: DYEING with super liqhtener

[0068] Each sample has been mixed with an oxidative dye in the ratio 1 :2 (dye: sample), applied to a hair lock in a natural colour (tone 6) and left on for 45 minutes.

[0069] Test 3: TONER (toning with dye)

[0070] Each sample has been mixed with a dye in the ratio 1 :2 (dye:sarmple), applied to a bleached hair lock (tone 9-10) and left on for 20 minutes.

[0071] The attached [Fig. 1] shows the results of the bleaching test 1 carried out using sample 1 with the three different concentrations of dyeing pigment: [0072] A = 0.005%, B = 0.01%, C = 0.1 %.

[0073] The attached [Fig. 2] shows the results of the bleaching test 1 carried out using sample 2 with the three different concentrations of dyeing pigment A, B, C.

[0074] In both figures it is possible to observe that an increase in the concentration of dyeing pigment is accompanied by an increasing development of a rose-orange tone on the hair, which darkens the hair colour, thus reducing the lightening effect.

[0075] It can be deduced that the lightening process, that is, the bleaching process, is more effective with lower concentrations of dyeing pigment.

[0076] The attached [Fig. 3] shows the results of the dyeing test 2 with super lightener carried out using sample 1 with the three different concentrations of dyeing pigment A, B, C.

[0077] The attached [Fig. 4] shows the results of the dyeing test 2 with super lightener carried out using sample 2 with the three different concentrations of dyeing pigment A, B, C.

[0078] Also in this case it is possible to observe in both figures that the lightening process is more effective with lower concentrations of dyeing pigment.

[0079] The attached [Fig. 5] shows the results of the toning test 3 with dye carried out using sample 1 with the three different concentrations of dyeing pigment A, B, C.

[0080] The toner is neutral.

[0081] It is possible to observe that an increase in the concentration of dyeing pigment in sample 1 is accompanied by an increasing development of a slight rose-orange colour on the hair, which interferes with the toning action. Consequently, also in this case it can be deduced that the toning process is more effective with lower concentrations of dyeing pigment.

[0082] The attached [Fig. 6] shows the results of the bleaching test 1 carried out using sample 3 with the three different concentrations of dyeing pigment A, B, C.

[0083] The attached [Fig. 7] shows the results of the bleaching test 1 carried out using sample 4 with the three different concentrations of dyeing pigment A, B, C. [0084] In both figures it is possible to observe that an increase in the concentration of dyeing pigment is accompanied by an increasing development of a rose-orange tone on the hair, which darkens the hair colour, thus reducing the lightening effect.

[0085] It can be deduced that the lightening process, that is, the bleaching process, is more effective with lower concentrations of dyeing pigment.

[0086] The attached [Fig. 8] shows the results of the dyeing test 2 with super lightener carried out using sample 4 with the three different concentrations of dyeing pigment A, B, C.

[0087] Also in this case it is possible to observe in both figures that the lightening process is more effective with lower concentrations of dyeing pigment. On the contrary, with higher concentrations the hair colour tends to darken.

[0088] The attached [Fig. 9] shows the results of the toning test 3 with dye carried out using sample 3 with the three different concentrations of dyeing pigment A, B, C.

[0089] The toner is neutral.

[0090] It is possible to observe that an increase in the concentration of dyeing pigment in sample 3 is accompanied by an increasing development of a slight rose-orange colour on the hair, which interferes with the toning action. Consequently, also in this case it can be deduced that the toning process is more effective with lower concentrations of dyeing pigment.

[0091] The protocols followed to carry out tests 1 , 2 and 3 are described in greater detail below.

[0092] Test 1

[0093] Protocol of application of coloured oxidizing solution with bleaching powder

1. The mixing ratio for using the powder mixed with the coloured oxidizing solution is 1 :2: 1 :1 .5 for dyes with tones from 3/ to 10/ (on a scale from 1/, corresponding to the darkest tone, that is, black, to 10/, corresponding to the lighest blonde tone), while for super lighteners it is 1 :2.

2. Use a plastic or glass bowl to mix the powder with the coloured oxidizing solution. 3. Use a scale to weigh first the powder and then the coloured oxidizing solution according to the selected ratio.

4. Mix for 2-3 minutes until the mixture is perfectly homogeneous and without lumps.

5. Wait a few minutes before applying the product to the head.

6. Apply the product to the dry hair.

7. Leave it on for 45 to 50 minutes.

8. Periodically check the bleaching result while the mixture is on, handling the hair lock with the fingers.

[0094] Test 2

[0095] Protocol for the application of coloured oxidizing solution with oxidative dyes

1 . The mixing ratio for using oxidative dyes mixed with the coloured oxidizing solution is 1 :1.5 for dyes from 3/ to 10/, while for super lighteners it is 1 :2.

2. Use a plastic or glass bowl to mix the dye with the coloured oxidizing solution.

3. Use a scale to weigh first the dye and then the coloured oxidizing solution according to the selected ratio.

4. Mix for 2-3 minutes until the mixture is perfectly homogeneous and without lumps.

5. Wait 1 minute before applying the product to the head.

6. Apply the mixture to the dry hair.

7. Leave it on for 45 to 50 minutes according to the dye used.

8. Periodically check the dyeing result while the mixture is on, handling the hair lock with the fingers.

[0096] Test 3

[0097] Protocol for the application of coloured oxidizing solution with toner

1 . The mixing ratio for using oxidative toners mixed with the coloured oxidizing solution is 1 :2.

2. Use a plastic or glass bowl to mix the dye with the coloured oxidizing solution. 3. Use a scale to weigh first the dye and then the coloured oxidizing solution according to the selected ratio.

4. Mix for 2-3 minutes until the mixture is perfectly homogeneous and without lumps.

5. Wait 1 minute before applying the product to the head.

6. Apply the mixture to the dry hair.

7. Leave it on for 20 minutes.

8. Periodically check the dyeing result while the mixture is on, handling the hair lock with the fingers.

[0098] Therefore, with reference to the description provided above and the attached drawings, the following claims are expressed.