Non-oxidative hair dye composition and non-oxidative hair dyeing method

Abstract

The present invention relates to a non-oxidative hair dye composition, a non-oxidative hair dyeing method, and the use of said composition. The composition contains a specific direct dye, a fatty alcohol, a surfactant, and a buffer system.

Description

Technical Field

[0001] The present invention relates to a non-oxidative hair dye composition, a non-oxidative hair dyeing method, and use for improving the uptake of a specific hair direct dye into hair.

Background Art

[0002] Today, customers in the cosmetics industry are seeking hair color products that can dye hair without damaging it and without the need to visit a beauty salon for a long time. At the same time, bright, shiny, long-lasting, and color-uniform hair coloring is also desired. Usually, to quickly change the color of hair, hair direct dyes have become a common means for customer satisfaction. However, since customer satisfaction with the dyeing results is often not high, the prior art has tried to solve these problems.

[0003] Patent Documents 1 and 2 disclose a buffer system with a pH of less than 6 and a two-step hair treatment process for anionic direct dyes. In contrast to these disclosures, the present invention utilizes a different pH range and employs a one-step treatment with a ready-to-use composition. Patent Document 3 discloses a hair direct dye composition that is mixed with an oxidative or non-oxidative second composition at a pH of less than 4 or greater than 9. However, in order to further improve non-oxidative dyeing, which is an object of the present invention, not only a buffer system but also different pHs are required. Non-Patent Documents 1 and 2 disclose hair dye products containing hair direct dyes, surfactants, and aliphatic alcohols, but these products do not employ the buffer system of the present invention.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Document

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The inventors have unexpectedly found that a composition containing a surfactant, an aliphatic alcohol, and a buffer system in the pH range of 6 to 8.5 improves the uptake of hair direct dyes into hair. Although many attempts have been made in the prior art, there is no disclosure of the configuration and technical effects of the present invention. The present invention provides a hair color that is dark, bright, shiny, does not fade, and has no color unevenness, and this hair color can be applied to hair quickly.

Means for Solving the Problems

[0007] That is, the first object of the present invention is a non-oxidative hair dye composition having a pH in the range of 6 to 8.5, a) one or more surfactants selected preferably from anionic surfactants, amphoteric / bzwitterionic surfactants and / or nonionic surfactants and / or mixtures thereof, b) one or more aliphatic alcohols having a linear or branched, saturated or unsaturated C 12 ~C 22 hydrocarbon chain and / or mixtures thereof, c) one or more hair direct dyes selected from anionic and / or nonionic hair direct dyes and / or mixtures thereof, d) one or more buffer systems having a buffering capacity of 0.002 g-equivalent / L to 0.5 g-equivalent / L in the pH range of 6 to 8.5, wherein the buffering capacity is measured by acid-base titration of the composition diluted 1:10 with water under the atmosphere at 25°C A composition comprising

[0008] A second object of the present invention is a method for producing a non-oxidizing hair color composition, comprising the following steps: i) Providing a first composition comprising at least one hair direct dye selected from anionic and / or nonionic direct dyes of compound c) defined above; ii) - At least one surfactant of compound a) defined above, - At least one aliphatic alcohol of compound b) defined above, - At least one buffer system having a buffering capacity of 0.002 g-equiv / L to 0.5 g-equiv / L in the range of pH 6 to 8.5 of feature d) defined above, the buffering capacity being measured by titrating the composition having an effective content of 10% by weight in the atmosphere at 25°C Providing a second composition comprising; iii) Mixing the compositions of steps i) and ii) to produce a ready-to-use composition having a pH in the range of 6 to 8.5; A production method comprising.

[0009] A third object of the present invention is - At least one surfactant of compound a) defined above, - At least one aliphatic alcohol of compound b) defined above, - At least one buffer system having a buffering capacity of 0.002 g-equiv / L to 0.5 g-equiv / L in the range of pH 6 to 8.5 of feature d) defined above, the buffering capacity being measured by titrating the composition having an effective content of 10% by weight in the atmosphere at 25°C Use of the composition comprising for improving the uptake of anionic and / or nonionic direct dyes of compound c) defined above into hair.

[0010] Another object of the present invention is the following steps: iv) Applying the ready-to-use mixture defined above to the hair for 1 to 60 minutes. v) optionally rinsing the hair A non-oxidative hair coloring method comprising:

[0011] A further object of the present invention is Part A comprising one or more anionic and / or nonionic dyes of compound c) as defined above, - one or more surfactants of compound a) as defined above, - a linear or branched, saturated or unsaturated C 12 ~C 22 one or more aliphatic alcohols having a hydrocarbon chain, - one or more buffer systems having a buffering capacity of 0.002 g-equivalent / L to 0.5 g-equivalent / L in the pH range of 6 to 8.5 of feature d) as defined above, the buffering capacity being measured by titrating the composition having an effective content of 10% by weight in the atmosphere at 25°C Part B comprising: A two-component non-oxidative dyeing composition.

[0012] A further object of the present invention is a kit of parts comprising two compositions that are stored separately until immediately before use, wherein the first separate composition comprises one or more anionic and / or nonionic dyes of compound c) as defined above, and the second separate composition comprises - one or more surfactants of compound a) as defined above, - one or more aliphatic alcohols of compound b) as defined above, - one or more buffer systems having a buffering capacity of 0.002 g-equivalent / L to 0.5 g-equivalent / L in the pH range of 6 to 8.5 of feature d) as defined above, the buffering capacity being measured by titrating the composition having an effective content of 10% by weight in the atmosphere at 25°C, a kit of parts.

Embodiments for Carrying Out the Invention

[0013] The present invention improves the adhesion of anionic and / or nonionic direct hair dyes to hair fibers. Without wishing to be bound by any theory, it is believed that this buffering composition provides a formulation medium, thereby stably accommodating the direct hair dye in solution and thus achieving the affinity of the hair dye for hair. In particular, this buffering system facilitates the uptake of the hair dye into the hair fibers.

[0014] the compound of (a) The composition according to the present invention preferably comprises one or more surfactants selected from anionic surfactants, cationic surfactants, amphoteric / zwitterionic surfactants and / or nonionic surfactants and / or mixtures thereof, more preferably one or more surfactants selected from anionic surfactants, amphoteric / zwitterionic surfactants and / or nonionic surfactants and / or mixtures thereof.

[0015] Suitable anionic surfactants include alkylbenzene sulfonates, alkyl or alkenyl ether sulfates, alkyl or alkenyl sulfates, olefin sulfonates, alkane sulfonates, saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates, α-sulfo fatty acid salts, N-acyl amino acids, mono- or diesters of phosphoric acid, and sulfosuccinate esters. Examples of anionic surfactants include sodium cetearyl phosphate and sodium lauryl sulfate.

[0016] Suitable cationic surfactants include monoalkyltrimethylammonium chloride, dialkyldimethylammonium chloride, and monoalkyltrimethylammonium bromide. Examples of cationic surfactants include cetrimonium chloride and behentrimonium chloride.

[0017] Suitable nonionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, higher fatty acid sucrose esters, polyglycerin fatty acid esters, higher fatty acid mono- or diethanolamides, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, alkyl saccharides, alkylamine oxides, and alkylamide amine oxides. Examples of nonionic surfactants include cetareth-30 and PEG-40 hydrogenated castor oil.

[0018] Suitable amphoteric surfactants include imidazolines, carbobetaines, amidobetaines, sulfobetaines, hydroxysulfobetaines, and amidosulfobetaines. Examples of amphoteric surfactants include coco betaine and cocoamidopropyl betaine.

[0019] From the viewpoint of imparting color intensity to hair, an anionic surfactant is preferred as surfactant a).

[0020] From the viewpoints of emulsion stability and imparting color intensity to hair, the most preferred anionic surfactant is sodium cetearyl phosphate.

[0021] In principle, the composition of the present invention can contain one or more cationic surfactants and / or cationic polymers. However, from the viewpoint of imparting color intensity to hair, the total equivalent molar ratio of the cationic surfactant and / or cationic polymer to one or more direct hair dyes of compound c) is preferably 15 or less, more preferably 10 or less, and still more preferably 5 or less.

[0022] In short, from the viewpoint of improving color intensity, it is preferable to make the molar concentration of the dye excessive compared to the cationic surfactant and / or polymer.

[0023] In a more preferred embodiment of the present invention, from the viewpoint of improving color intensity, the composition of the present invention does not contain a cationic polymer and / or a cationic surfactant.

[0024] From the perspective of the stability of the composition, the total concentration of compound a) calculated based on the entire composition is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and still more preferably 0.3% by weight or more.

[0025] From the perspective of product cost, the total concentration of compound a) calculated based on the entire composition is preferably 10% by weight or less, more preferably 8% by weight or less, still more preferably 5% by weight or less, and still more preferably 3% by weight or less.

[0026] To achieve the above effects, the total concentration of compound a) calculated based on the total weight of the composition is preferably in the range of 0.1% by weight to 10% by weight, more preferably in the range of 0.2% by weight to 8% by weight, still more preferably in the range of 0.3% by weight to 5% by weight, and still more preferably in the range of 0.3% by weight to 3% by weight.

[0027] In a preferred embodiment of the present invention, from the perspective of the stability of the composition, the surfactant of compound a) is preferably an anionic surfactant, and the total concentration of the anionic surfactant calculated based on the total weight of the composition is preferably in the range of 0.1% by weight to 10% by weight, more preferably in the range of 0.2% by weight to 8% by weight, still more preferably in the range of 0.3% by weight to 5% by weight, and still more preferably in the range of 0.3% by weight to 3% by weight.

[0028] Compound of b) The composition of the present invention contains, as the compound of b), one or more aliphatic alcohols having a linear or branched, saturated or unsaturated C 12 ~C 22 hydrocarbon chain and / or mixtures thereof.

[0029] Linear or branched, saturated or unsaturated C 12 ~C 22Suitable aliphatic alcohols having an alkyl chain include, for example, lauryl alcohol, tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, palmitoleyl alcohol, heptadecyl alcohol, stearyl alcohol, oleyl alcohol, nonadecyl alcohol, arachidyl alcohol, behenyl alcohol and / or mixtures thereof.

[0030] From the viewpoints of imparting color intensity to hair and providing a conditioning effect, one or more aliphatic alcohols are branched or straight-chain, saturated or unsaturated C 14 ~C 18 aliphatic alcohols having an alkyl chain (preferably saturated C 14 ~C 18 alkyl chains) and / or mixtures thereof. More preferably, they are mixtures of straight-chain, saturated C 16 and C 18 aliphatic alcohols having an alkyl chain.

[0031] From the viewpoints of compatibility as a cosmetic, imparting color intensity to hair, and providing a conditioning effect, cetearyl alcohol is preferred as the aliphatic alcohol.

[0032] From the viewpoints of imparting color intensity to hair and providing a conditioning effect to dyed hair, the preferred total concentration of aliphatic alcohol b) calculated based on the total weight of the composition is preferably 1% by weight or more, more preferably 2% by weight or more, and even more preferably 3% by weight or more.

[0033] From the viewpoints of imparting color intensity to hair, providing a conditioning effect to dyed hair, and realizing a composition with storage stability, the total concentration of aliphatic alcohol b) calculated based on the total weight of the composition is preferably 20% by weight or less, more preferably 15% by weight or less, and even more preferably 10% by weight or less.

[0034] Preferably, in order to achieve the above effects, the total concentration of the aliphatic alcohol b), calculated based on the total weight of the composition, is in the range of 1% to 20% by weight, more preferably in the range of 2% to 15% by weight, and still more preferably in the range of 3% to 10% by weight.

[0035] Compound of c) The composition of the present invention contains, as the compound of c), one or more hair direct dyes selected from anionic and / or nonionic hair direct dyes.

[0036] In the scope of meaning of the present invention, "anionic and / or nonionic hair direct dyes" means the ionic properties of the dyes under the conditions of pH 6 to 8.5.

[0037] From the viewpoint of imparting color intensity to the hair, it is preferable that one or more hair direct dyes of the compound c) are selected from nonionic hair direct dyes. Therefore, each dye is nonionic at pH 6 to 8.5.

[0038] All suitable dyes that satisfy the above definitions can be used for the purposes of the present invention.

[0039] Suitable anionic direct dyes include Acid Black 1, Acid Blue 1, Acid Blue 3, Food Blue 5, Acid Blue 7, Acid Blue 9, Acid Blue 74, Acid Orange 3, Acid Orange 6, Acid Orange 7, Acid Orange 10, Acid Red 1, Acid Red 14, Acid Red 18, Acid Red 27, Acid Red 50, Acid Red 52, Acid Red 73, Acid Red 87, Acid Red 88, Acid Red 92, Acid Red 155, Acid Red 180, Acid Violet 9, Acid Violet 43, Acid Violet 49, Acid Yellow 1, Acid Yellow 23, Acid Yellow 3, Food Yellow No. 8, D&C Brown No. 1, D&C Green No. 5, D&C Green No. 8, D&C Orange No. 4, D&C Orange No. 10, D&C Orange No. 11, D&C Red No. 21, D&C Red No. 27, D&C Red No. 33, D&C Violet 2, D&C Yellow No. 7, D&C Yellow No. 8, D&C Yellow No. 10, FD&C Red 2, FD&C Red 40, FD&C Red No. 4, FD&C Yellow No. 6, FD&C Blue 1, Food Black 1, Food Black 2, Disperse Black 9, Disperse Violet 1 and their alkali metal (sodium, potassium, etc.) salts. Among these, the most preferred anionic dyes are Acid Red 52, DC Violet 2, DC Red 33, DC Orange 4, DC Red 27, DC Yellow 10, HC Blue 18, HC Red 18 and HC Yellow 16.

[0040] Suitable nonionic dyes containing nitro dyes are HC Blue No. 2, HC Blue No. 4, HC Blue No. 5, HC Blue No. 6, HC Blue No. 7, HC Blue No. 8, HC Blue No. 9, HC Blue No. 10, HC Blue No. 11, HC Blue No. 12, HC Blue No. 13, HC Brown No. 1, HC Brown No. 2, HC Green No. 1, HC Orange No. 1, HC Orange No. 2, HC Orange No. 3, HC Orange No. 5, HC Red BN, HC Red No. 1, HC Red No. 3, HC Red No. 7, HC Red No. 8, HC Red No. 9, HC Red No. 10, HC Red No. 11, HC Red No. 13, HC Red No. 54, HC Red No. 14, HC Violet BS, HC Violet No. 1, HC Violet No. 2, HC Yellow No. 2, HC Yellow No. 4, HC Yellow No. 5, HC Yellow No. 6, HC Yellow No. 7, HC Yellow No. 8, HC Yellow No. 9, HC Yellow No. 10, HC Yellow No. 11, HC Yellow No. 12, HC Yellow No. 13, HC Yellow No. 14, HC Yellow No. 15, 2-amino-6-chloro-4-nitrophenol, picramic acid, 1,2-diamino-4-nitrobenzene, 1,4-diamino-2-nitrobenzene, 3-nitro-4-aminophenol, 1-hydroxy-2-amino-3-nitrobenzene and 2-hydroxyethyl picramic acid.

[0041] However, from the viewpoint of color strength, the most preferred direct hair dyes of compound c) are selected from HC Blue 18, HC Red 18, HC Yellow 16 and / or mixtures thereof.

[0042] From the viewpoint of imparting sufficient color strength to the hair, the total concentration of direct dye c) calculated based on the total weight of the composition is preferably 0.01% by weight or more, more preferably 0.02% by weight or more.

[0043] From the viewpoint of product cost, the total concentration of direct dye c) calculated based on the total weight of the composition is preferably 0.8% by weight or less, more preferably 0.25% by weight or less.

[0044] Preferably, in order to achieve the above effects, the total concentration of direct dye c calculated based on the total weight of the composition is 0.01% to 0.8% by weight, more preferably 0.02% to 0.25% by weight.

[0045] In one aspect of the present invention, from the perspective of product cost, the total concentration of the direct dye selected from HC Blue 18, HC Red 18, HC Yellow 16 and / or mixtures thereof, calculated based on the total weight of the composition, is preferably 0.01% to 0.8% by weight, more preferably 0.02% to 0.25% by weight.

[0046] Feature of d) The composition of the present invention is one or more buffer systems having a buffering capacity of 0.002 g - equivalent / L to 0.5 g - equivalent / L in the pH range of 6 to 8.5 of feature d), and the buffering capacity is measured by acid - base titration of the composition diluted 1:10 with water in the atmosphere at 25°C, and includes a buffer system.

[0047] The measurement of the buffering capacity is carried out as follows. Dilute 10 mL of the hair dye composition with water to 100 mL. Measure the pH of the resulting solution by appropriate means such as a pH electrode. Subsequently, dropwise add and titrate 1N hydrochloric acid or sodium hydroxide aqueous solution to the target solution to determine the volume (x [mL]) of acid / base required to decrease / increase the pH of the hair dye composition solution by 1 unit. Since the density of the hydrochloric acid / sodium hydroxide solution can be regarded as 1 g / cm 3 and the volume is expressed in [g]. The buffering capacity is calculated by the following formula. Buffering capacity = x [g] * 10 / 1000 [gram - equivalent / L]

[0048] From the viewpoints of the degree of freedom in formulation and imparting color intensity to hair, the buffering capacity in d) is preferably 0.003 g - equivalent / L to 0.25 g - equivalent / L, more preferably 0.003 g - equivalent / L to 0.1 g - equivalent / L, and still more preferably 0.003 g - equivalent / L to 0.05 g - equivalent / L in the pH range of 6 to 8.5. The buffering capacity is measured by acid - base titration of the composition diluted 1:10 with water in the atmosphere at 25°C.

[0049] Examples of suitable buffer systems in the pH range of 6 to 8.5 include disodium hydrogen phosphate and sodium dihydrogen phosphate; dipotassium hydrogen phosphate and potassium dihydrogen phosphate; disodium hydrogen phosphate and citric acid; and boric acid and sodium hydroxide.

[0050] From the viewpoint of compatibility as a cosmetic, a phosphate buffer system is preferred as the buffer system in d). The phosphate buffer system contains at least one phosphate as in the first three buffer systems exemplified above. The most preferred buffer systems are disodium hydrogen phosphate and sodium dihydrogen phosphate, and dipotassium hydrogen phosphate and potassium dihydrogen phosphate.

[0051] From the viewpoint of the buffering capacity of the phosphate buffer system, the pH of the composition of the present invention is preferably 6 to 8.

[0052] From the viewpoint of providing sufficient buffering capacity, the total concentration of the buffer salts calculated based on the total weight of the composition is preferably 0.1% by weight or more, more preferably 0.25% by weight or more, and still more preferably 0.5% by weight or more.

[0053] From the viewpoint of acceptability as a cosmetic, the total concentration of the buffer salts calculated based on the total weight of the composition is preferably 10% by weight or less, more preferably 8% by weight or less, and still more preferably 5% by weight or less.

[0054] Preferably, in order to achieve the above effects, the total concentration of the buffer salt calculated based on the total weight of the composition is 0.1% by weight to 10% by weight, more preferably 0.25% by weight to 8% by weight, and still more preferably 0.5% by weight to 5% by weight.

[0055] The total molar concentration of the buffer salt is preferably 0.01 M to 0.5 M.

[0056] In one aspect of the present invention, the total concentration of the phosphate of the phosphate buffer system calculated based on the total weight of the composition is 0.1% by weight to 10% by weight, more preferably 0.25% by weight to 8% by weight, and still more preferably 0.5% by weight to 5% by weight.

[0057] pH adjustment From the viewpoint of adjusting the pH to a desirable range of 6 to 8.5, it should be noted that those skilled in the art will select appropriate acids and bases based on their compatibility with the composition of the present invention. Suitable acids are hydrochloric acid and phosphoric acid, and suitable bases are sodium hydroxide and potassium hydroxide.

[0058] Method for producing non-oxidative hair dye composition and hair dyeing method The present invention also relates to a method for producing a non-oxidative hair dye composition, the method comprising the following steps: i) providing a first composition comprising one or more hair direct dyes selected from the anionic and / or nonionic direct dyes of compound c) defined above; ii) - one or more surfactants of compound a) defined above, - one or more aliphatic alcohols of compound b) defined above, - one or more buffer systems having a buffering capacity of 0.002 g-equivalent / L to 0.5 g-equivalent / L in the pH range of 6 to 8.5 of feature d) defined above, the buffering capacity being measured by titrating the composition having an effective content of 10% by weight in the atmosphere at 25°C providing a second composition comprising; iii) mixing the compositions of steps i) and ii) to produce a ready-to-use composition having a pH range of 6 to 8.5. Relates to a manufacturing method including

[0059] This immediately available composition preferably contains one or more cationic surfactants and / or cationic polymers at a total equivalent molar ratio of 15 or less, preferably 10 or less, more preferably 5 or less, to one or more direct hair dyes of compound c) in the immediately available composition, from the viewpoint of color strength.

[0060] More preferably from the viewpoint of color strength, the immediately available composition does not contain a cationic polymer and / or a cationic surfactant.

[0061] The present invention is a non-oxidative hair coloring method, comprising the following steps: iv) applying the immediately available mixture defined above to the hair for 1 minute to 60 minutes, v) optionally rinsing the hair Relates to a method including

[0062] From the viewpoint of imparting high color strength and user convenience to the hair, the immediately available mixture in step iv) preferably remains on the hair for 5 minutes to 20 minutes.

[0063] According to step v) of the method, the immediately available mixture can be a leave-in type composition and is not washed off the hair. This is particularly preferred for customers who want to thoroughly condition their hair.

[0064] Similarly, the immediately available mixture in step v) is preferably a rinse-off type composition and is washed off the hair. This is particularly preferred for customers who do not want the drooping effect due to the weight of the leave-in type composition.

[0065] From the viewpoint of improving the hair color intensity, in one embodiment of the method of the present invention described above, the immediately usable composition in step iv) contains one or more cationic surfactants and / or cationic polymers in a total equivalent molar ratio of 15 or less, preferably 10 or less, more preferably 5 or less, relative to one or more direct dyes for hair of compound c).

[0066] From the viewpoint of improving the hair color intensity, in a preferred embodiment of the method of the present invention described above, the immediately usable composition in step iv) does not contain a cationic surfactant and / or a cationic polymer.

[0067] Use of the composition As defined above, one object of the present invention is also the use of the composition of the present invention for improving the uptake of the anionic and / or nonionic direct dyes of compound c) as defined above into the hair.

[0068] From the viewpoint of improving the color intensity, in one embodiment of the use of the present composition as defined above, the present composition contains one or more cationic surfactants and / or cationic polymers in a total equivalent molar ratio of 15 or less, preferably 10 or less, more preferably 5 or less, relative to one or more direct dyes for hair of compound c).

[0069] From the viewpoint of the color uptake of the composition as defined above, it is a preferred embodiment of the present use that the present composition does not contain a cationic surfactant and / or a cationic polymer.

[0070] Two-component dyeing composition As defined above, the present invention comprises part A containing one or more anionic and / or nonionic dyes of compound c) as defined above, - one or more surfactants of compound a) as defined above, - a linear or branched, saturated or unsaturated C 12 ~C 22 one or more aliphatic alcohols having a hydrocarbon chain, - One or more buffer systems having a buffering capacity of 0.002 g - equivalent / L to 0.5 g - equivalent / L in the pH range of 6 to 8.5 of the feature d) defined above, wherein the buffering capacity is measured by titrating the composition having an effective content of 10% by weight in the atmosphere at 25°C A two - part non - oxidative hair dye composition containing part B is one of the objects of the present invention.

[0071] The part A and part B of this two - part composition are kept separate until immediately before application to the hair.

[0072] In the present invention, when incompatibility is expected with components other than the components defined above, it is preferable to use a two - part composition. Such lack of compatibility may occur during storage of the composition.

[0073] Kit of parts As defined above, one object of the present invention relates to a kit of parts containing two compositions that are stored separately until immediately before use. Here, the first independent composition contains one or more anionic and / or non - ionic dyes defined as compound c) above, and the second independent composition contains - One or more surfactants of compound a) defined above, - One or more aliphatic alcohols of compound b) defined above, - One or more buffer systems having a buffering capacity of 0.002 g - equivalent / L to 0.5 g - equivalent / L in the pH range of 6 to 8.5 of the feature d) defined above, wherein the buffering capacity is measured by titrating the composition having an effective content of 10% by weight in the atmosphere at 25°C

Examples

[0074] Examples, Comparative Examples The hair dye compositions shown in Table 1 were prepared as described below. For the obtained hair dye compositions, "buffering capacity" and "C*" were evaluated in the following "Method" section. These results are summarized in Table 1 below. Examples 13 - 22 obtained by the same method are shown in Table 2.

[0075] Method for preparing a hair dye composition Compound c) was dissolved in water. This solution was stirred for a predetermined time to prepare a first composition. Separately, component a), component b), disodium hydrogen phosphate and sodium dihydrogen phosphate were dissolved in water to prepare a second composition. Subsequently, this second composition was mixed with the first composition, and the resulting mixture was stirred for a predetermined time to obtain a hair dye composition.

[0076] [Table 1]

[0077] [Table 2]

[0078] Example 22 First composition wt% Aminomethylpropanol 5.0 HC Red 18 2.0 HC Yellow 16 0.5 Fragrance appropriate amount 1,2 - Propylene glycol total amount to 100.0

[0079] Second composition wt% Sodium lauryl sulfate 3.0 Stearyl alcohol 2.0 Disodium hydrogen phosphate 2.5 Sodium dihydrogen phosphate 0.3 NaOH / HCl appropriate amount to adjust pH to 8.0 Water total amount to 100.0

[0080] Mix 0.5 mL of the first composition with 20 mL of the second composition to obtain a mixture that can be used immediately. Examples 22is a specific example of the second object of the present invention, and further a two-component composition and a kit of parts.

[0081] Method Measurement of buffering capacity In the present invention, the buffering capacity means a numerical value determined from the following formula, using the concentration of acid required to lower the pH of a 10% aqueous solution of the target composition by 1 unit from the initial value at 25°C as the measured value. Buffering capacity = ΔC a / ΔpH (In the formula, C a is the ionic concentration of the acid (abbreviated as gram equivalent / L, g equivalent / L).)

[0082] In the above examples, the buffering capacity of each composition was determined as follows. 10 mL of the hair dye composition was diluted with water to 100 mL, and the pH of the resulting solution was measured. 1N hydrochloric acid aqueous solution was dropped into the target solution for titration, and the volume of acid (x [mL]) required to lower the pH of the hair dye composition solution by 1 unit was determined. Since the density of the hydrochloric acid solution can be regarded as 1 g / cm 3 , the volume is expressed in [g]. The buffering capacity is calculated by the following formula. Buffering capacity = x [g] * 10 / 1000 [gram equivalent / L]

[0083] Hair dyeing experiment Yak hair (a hair bundle with 2 g of hair fibers per strand) was purchased from International Hair Importer (Glendale, NY, USA). This hair was bleached at 40°C for 30 minutes with a commercially available bleach (trade name Goldwell Silkift Control). After shampooing this hair bundle, it was dried with a blow dryer. Subsequently, 1 g of the above hair dye composition was applied to the decolorized yak hair and left on the hair at room temperature for 3 minutes. This hair bundle was rinsed once with water at 37°C for 1 minute. The color strength was measured with DataColor 45G (equipment of DataColor). The chroma according to the CIE*lab system was measured and shown as C* above. The chroma corresponds to the color strength.

Claims

1. A non-oxidative hair dye composition having a pH in the range of 6 to 8.5, a) an anionic surfactant in an amount of 0.3% by weight or more and 5% by weight or less, b) cetearyl alcohol in an amount of 2% by weight or more and 10% by weight or less, c) one or more direct hair dyes selected from HC Blue 18, HC Red 18, HC Yellow 16, and mixtures thereof in an amount of 0.01% by weight or more and 0.25% by weight or less, d) a buffer system of disodium hydrogen phosphate and sodium dihydrogen phosphate having a buffering capacity of 0.003 g-equivalent / L to 0.05 g-equivalent / L in the pH range of 6 to 8.5, the buffering capacity being measured by acid-base titration of the composition diluted with water at a volume ratio of 1:10 in the atmosphere at 25°C, The non-oxidative hair dye composition comprising the above components.

2. The composition according to claim 1, wherein the surfactant in a) is sodium cetearyl phosphate and / or sodium lauryl sulfate.

3. The composition according to claim 1 or 2, comprising one or more cationic surfactants and / or cationic polymers, and the total equivalent molar ratio of the cationic surfactant and / or cationic polymer to one or more direct hair dyes in c) being 15 or less.

4. The composition according to claim 1 or 2, not containing a cationic surfactant and / or a cationic polymer.

5. The composition according to any one of claims 1 to 4, wherein the total concentration of the buffer salts calculated based on the total weight of the composition is 0.1% by weight to 10% by weight.

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