Oxidation hair dye

Abstract

To provide an oxidation hair dye that enables hair to be dyed in a dark tone close to black, while reducing damage to the hair and preventing significant color unevenness.SOLUTION: The present invention provides an oxidation hair dye comprising a first agent comprising an oxidation dye and an alkali agent, and a second agent comprising an oxidizing agent, wherein the two agents are mixed at a weight ratio of 1:1 to 1:3, the oxidation dye is comprised in an amount of 0.1 to 7.0 wt.% relative to the total amount of the two agents mixed together, wherein p-methylaminophenol and 2,2'-[(4-aminophenyl)imino]bisethanol are used as precursors, while resorcinol, meta-aminophenol, and 5-amino-o-cresol are used as couplers.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an oxidation hair dye suitable for dyeing hair, for example, to a dark color tone close to black hair (value of 3.5 or less and chroma of 3 or less in the JIS color name book (based on JIS Z 8102)). [Background technology]

[0002] In Japan, when people dye their hair to darken the color of their bleached hair or to make gray hair less noticeable for special occasions such as weddings, funerals, and job hunting, they often dye their hair a dark color close to the black hair characteristic of Japanese people (a hue relatively close to black hair, such as black or dark brown). For such coloring, oxidative hair dyes (hair colors that develop color through the oxidative polymerization of oxidative dyes) are generally used.

[0003] Oxidative hair dyes are dyes that penetrate the hair with an oxidative dye and oxidatively polymerize the oxidative dye with an oxidizing agent to develop color, and two-part oxidative hair dyes are widely used, in which a first part containing an oxidative dye and an alkaline agent is mixed with a second part containing hydrogen peroxide (an example of an oxidizing agent).The alkaline agent is mixed into the first part to swell the hair and promote the penetration of the oxidative dye into the hair, as well as to activate the hydrogen peroxide.

[0004] And, a precursor (dye intermediate) and a coupler (toning agent) are mixed in the oxidation dye. When the precursor is oxidized by an oxidizing agent, it polymerizes and develops a color, and when the coupler is oxidized alone, it hardly develops a color, but when it is oxidized together with the precursor, it develops a color different from the color developed by the precursor alone, and the combination of the precursor and the coupler is determined according to the desired color. Also, for example, when dyeing hair in a blue color, only the precursor and the coupler that develop a blue color are used, and the precursor and the coupler that develop a color other than blue can be unnecessary. In this way, depending on the desired color, only the combination of the precursor and the coupler that develops a single color can be used, but when a dark color tone close to black hair is developed, the oxidation dye is made by combining the precursor and the coupler that develops a plurality of colors such as yellow, brown, purple, and blue. In general, the color development tends to be more unstable when a combination of a precursor and a coupler that develops a plurality of color systems is used compared to when only a combination of a precursor and a coupler that develops a single color system is used. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-057165 A [Patent Document 2] JP 2016-088891 A Summary of the Invention [Problem to be solved by the invention]

[0006] Oxidation dyes with strong dyeing power are used when trying to obtain stable dyeing power that is not affected by differences in hair quality due to gender, age, etc. Conventionally, when making oxidation dyes that can produce dark colors close to black hair and have strong dyeing power, paraphenylenediamine or toluene-2,5-diamine have been selected as precursors, and in these cases, resorcinol and meta-aminophenol are indispensable couplers.

[0007] Here, when paraphenylenediamine or toluene-2,5-diamine is selected as a precursor, resorcinol as a coupler (in this case, a coupler that produces a yellow color) requires a certain level of pH value and alkalinity to produce color, and the color becomes significantly weaker as the pH value or the amount of alkali decreases, and the balance of the color produced by the oxidative hair dye containing this is lost.

[0008] In addition, when paraphenylenediamine or toluene-2,5-diamine is selected as a precursor, meta-aminophenol as a coupler (in this case, it is a coupler that develops a brown color) takes a certain amount of time to develop color. Therefore, if the time left is short, the brown color will become lighter, and hair dyed with an oxidation hair dye containing this will not be as dark as black hair.

[0009] Incidentally, when it comes to hair that has been repeatedly colored, the new growth (mainly the part near the roots of the hair) that has not been colored tends to be more difficult to dye than the already dyed parts (mainly the part from the middle to the ends of the hair) that have been colored. In addition, oxidative hair dyes that have increased dyeing power so that the new growth can be dyed thoroughly are excessive for the already dyed parts and also cause extra damage to the hair. The longer the hair, the greater the volume of the already dyed parts in the entire hair, which causes a problem of increased burden on the entire hair.

[0010] Therefore, in beauty salons, different treatment methods are sometimes used for dyed and new hair growth areas. In other words, in oxidative hair dyes consisting of a first agent and a second agent, the mixing ratio of the two agents is basically 1:1, and is set so that sufficient dyeing effect can be achieved at this time. Therefore, the oxidative hair dye with this mixing ratio (1:1) is applied to the new hair growth area, and an oxidative hair dye with a mixing ratio of the first agent and the second agent changed to 1:2-3 (1:2-1:3) is applied to the dyed area. In this method, the burden on the dyed area is reduced by reducing the amount of alkali, but in the above-mentioned conventional oxidative hair dyes that use resorcin as a coupler, the color development of resorcin becomes significantly weaker as the amount of alkali decreases, making it difficult to develop a dark color tone close to black hair.

[0011] Another method is to apply an oxidative hair dye with a 1:1 mixture ratio to the new hair growth, and then apply the same agent to the already dyed hair after a certain period of time. In other words, the burden on the hair can be reduced to some extent by shortening the contact time of the oxidative hair dye with the already dyed hair, but with the above-mentioned conventional oxidative hair dyes that use meta-aminophenol as a coupler, the color development of meta-aminophenol becomes insufficient as the time left for the dye is shortened, and it is still not possible to develop a dark color close to that of black hair.

[0012] In recent years, the use of a second agent containing an acid has become common. This lowers the alkalinity and pH value of the mixture of the first and second agents, and certainly reduces the burden on the hair, but even in this case, there are drawbacks such as unstable color development and weak dyeing power.

[0013] There are also agents for damaged areas that reduce the amount of alkali in the first agent as much as possible and adjust the balance of the oxidative dyes to achieve the same color as the first agent for new growth. However, when this agent comes into contact with the agent for new growth on the hair, the color of that area is not stable.

[0014] Patent documents 1 and 2 report oxidative hair dyes for dyeing gray hair, but neither of them improves the unstable color development that occurs when considering reducing the burden on damaged areas (already dyed areas).

[0015] As a result of research into achieving both dyeability and reduced burden on hair, the inventors have discovered that by using paramethylaminophenol and 2,2'-[(4-aminophenyl)imino]bisethanol, which have traditionally been used as auxiliary agents, as precursors instead of paraphenylenediamine or toluene-2,5-diamine, it is possible to dye hair without significant color variation to dark shades close to black hair, such as the desired dark brown or a similar black, even while reducing the burden on the hair (already dyed areas) by selecting resorcinol or meta-aminophenol as a coupler and changing the mixing ratio of the first and second agents to 1:2-3.

[0016] The present invention has been made in consideration of the above-mentioned matters, and an object of the present invention is to provide an oxidation hair dye that can dye hair in a dark color tone close to black without significant color variation while reducing the burden on hair. [Means for solving the problem]

[0017] In order to achieve the above object, the oxidation hair dye of the present invention is an oxidation hair dye using a mixture of a first agent containing an oxidation dye and an alkali agent and a second agent containing an oxidizing agent, the first agent and the second agent being mixed in a weight ratio of 1:1 to 1:3, The pH of the mixture is 7.2 to 9.3. For the total mixture of the first and second agents, the oxidation dye is 0.82~1.64% by weight, using paramethylaminophenol and / or its salts and 2,2'-[(4-aminophenyl)imino]bisethanol and / or its salts as precursors, and using resorcinol, meta-aminophenol, and 5-aminoorthocresol as couplers, the composition contains more resorcinol by weight than the total of meta-aminophenol and 5-aminoorthocresol, and more paramethylaminophenol and / or its salts, and is used for dyeing hair that has lost its melanin pigment or gray hair to a dark shade close to black hair (Claim 1).

[0018] In the above oxidation hair dye, para-aminophenol may also be used as a precursor (claim 2).

[0019] In the above-mentioned oxidation hair dye, one or more of ammonia and monoethanolamine may be blended as the alkaline agent (claim 3).

[0020] The above-mentioned oxidation hair dye may not contain paraphenylenediamine, toluene-2,5-diamine or salts thereof as a precursor (claim 4).

[0021] Effect of the Invention

[0022] The present invention provides an oxidation hair dye that reduces the burden on hair and allows dyeing hair in dark shades close to black without significant color variation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] An embodiment of the present invention will be described below.

[0024] The oxidative hair dye of the present invention is used to dye hair from which melanin pigment has been removed or gray hair in a dark color tone close to black hair (lightness 3.5 or less, chroma 3 or less in the JIS color name book, or lightness 4 or less, chroma 4 or less in the Munsell color system), and is composed of a first agent containing an oxidative dye and an alkaline agent, and a second agent containing an oxidizing agent, and is used, for example, by mixing the first agent and the second agent immediately before use and then applying it to the hair.

[0025] Furthermore, in order to reduce the burden on damaged hair areas when applied (applied) to those areas, the first and second agents of the present invention can be used to reduce the amount of alkaline agent in the mixture of the first and second agents by changing the mixing ratio (weight ratio) of the first and second agents from 1:1 to 1:2 to 3, by adding an acid agent to the second agent, which partially neutralizes the first and second agents when they are mixed and adjusts the pH value of the system at the time of mixing from alkaline to near neutral, and by shortening the usual leaving time of 30 minutes to half (15 minutes) to reduce the contact time of the mixture.

[0026] The couplers to be blended with the oxidation dye of the first agent are resorcinol, meta-aminophenol, and 5-amino-orthocresol, and may be used in combination with 2,6-diaminopyridine, 2,4-diaminophenoxyethanol hydrochloride, 5-(2-hydroxyethylamino)-2-methylphenol, and α-naphthol within a blending range that is not particularly limited as long as the effects of the present invention are achieved.

[0027] Also, a direct dye such as paranitroorthophenylenediamine may be blended with the oxidation dye of the first agent.

[0028] The precursors to be blended in the oxidation dye of the first agent are paramethylaminophenol and / or its salts, and 2,2'-[(4-aminophenyl)imino]bisethanol and / or its salts, and paraaminophenol may be used in combination within an unrestricted blending range as long as the effects of the present invention are exhibited. As described above, when resorcinol and meta-aminophenol are used as couplers, if paraphenylenediamine or toluene-2,5-diamine is selected as a precursor, there is a risk that the desired color development will not be achieved, so paraphenylenediamine, toluene-2,5-diamine, and their salts are not included as precursors.

[0029] Resorcin (coupler) produces a yellow color when combined with paramethylaminophenol (precursor), and a red color when combined with 2,2'-[(4-aminophenyl)imino]bisethanol (precursor). Metaaminophenol (coupler) produces a yellow color when combined with paramethylaminophenol (precursor), and a blue color when combined with 2,2'-[(4-aminophenyl)imino]bisethanol (precursor). 5-aminoorthocresol (coupler) produces a yellow color when combined with paramethylaminophenol (precursor), and a purple color when combined with 2,2'-[(4-aminophenyl)imino]bisethanol (precursor). And by combining paramethylaminophenol and / or its salts and 2,2'-[(4-aminophenyl)imino]bisethanol and / or its salts as precursors, and resorcinol, metaaminophenol and 5-aminoorthocresol as couplers, the desired dark color tone close to black hair can basically be achieved.

[0030] On the other hand, paraaminophenol (precursor) develops yellow, orange, and orange colors in combination with resorcin (coupler), metaaminophenol (coupler), and 5-aminoorthocresol (coupler), respectively, and by using this, it becomes easier to develop a color such as dark brown, which is a dark color close to the desired black hair. However, instead of using this paraaminophenol (precursor), it is possible to use paranitroorthophenylenediamine, which is a direct dye that develops orange by itself. In this way, if the desired hair color cannot be achieved by the color development only of the combination of the precursor and the coupler, a color that is close to the desired hair color in relation to the color development (a complementary color if the desired hair color is black) or a direct dye that develops a color close to that may be used.

[0031] The content of the oxidation dye is preferably 0.1 to 7.0% by weight, and more preferably 0.5 to 3.5% by weight, based on the total mixture of the first and second agents. If the content of the oxidation dye is less than 0.1% by weight, it is difficult to obtain sufficient hair dyeing power to achieve the object of the present invention, and even if it exceeds 7.0% by weight, it is difficult to obtain any greater hair dyeing power.

[0032] From the viewpoint of dyeing lightened hair or gray hair due to bleaching of melanin pigment to a dark color close to black hair, the total amount of paramethylaminophenol and / or a salt thereof, 2,2'-[(4-aminophenyl)imino]bisethanol and / or a salt thereof as precursors, and resorcinol, metaaminophenol and 5-aminoorthocresol as couplers is preferably 70% by weight or more, more preferably 80% by weight or more, of the total amount of the oxidation dye.

[0033] In addition, the blending ratio of paramethylaminophenol and / or a salt thereof (A) to 2,2'-[(4-aminophenyl)imino]bisethanol and / or a salt thereof (B) is not particularly limited as long as the effects of the present invention are exhibited. From the viewpoint of dyeing lightened hair or gray hair that has been bleached of melanin pigment to a dark color close to black hair, the weight percentage ratio of A:B is preferably 1:4 to 1:13, and more preferably 1:7 to 1:11.

[0034] Furthermore, the blending ratio of all precursors (III) to all couplers (IV) is not particularly limited as long as the effects of the present invention are exhibited, but from the viewpoint of dyeing lightened hair or gray hair that has been bleached of melanin pigment to a dark color close to black hair, the blending ratio by weight of III:IV is preferably 4:1 to 1:3, and more preferably 3:1 to 1:2.

[0035] The alkaline agent to be blended in the first agent is not particularly limited as long as it can be blended in the first agent, but from the viewpoint of dyeing light hair, particularly gray hair, to a dark tone close to black hair, it is preferable to use ammonia, monoethanolamine, ammonium bicarbonate, etc.

[0036] The content of the alkaline agent in the first agent is not particularly limited as long as it is sufficient to swell the hair to be dyed and promote the penetration of the oxidation dye into the hair, but from the viewpoint of dyeability of the hair, the alkalinity is preferably 1 mL or more, and more preferably 3 mL or more. The alkalinity refers to the number of mL of 0.1 mol / L hydrochloric acid solution required to neutralize 1 g of the sample.

[0037] From the viewpoint of irritation when the oxidative hair dye adheres to the scalp during hair dyeing, the alkalinity is preferably 15 mL or less, more preferably 12 mL or less. For these reasons, the content of the alkaline agent in the first agent is 1 to 15 mL, more preferably 3 to 12 mL, in terms of alkalinity.

[0038] On the other hand, the second agent contains an oxidizing agent as an essential component in order to exert the effects of the present invention. As the oxidizing agent, it is considered to use hydrogen peroxide.

[0039] The content of the oxidizing agent (hydrogen peroxide) in the second agent is not particularly limited as long as it exerts the effects of the present invention. From the viewpoint of dyeability, the content of the oxidizing agent (hydrogen peroxide) is preferably 0.5 to 5.0% by weight, and more preferably 2 to 3.5% by weight, based on the total mixture of the first agent and the second agent. If the content is less than 0.5% by weight, it is difficult to obtain sufficient hair dyeing power to achieve the object of the present invention, and even if it is blended in more than 5.0% by weight, it is difficult to obtain any more hair dyeing power.

[0040] From the viewpoint of reducing the burden on damaged hair (already dyed parts), in particular, an acid (acidic substance) may be blended in the second agent within the scope of the present invention. Specific examples of acids include phosphoric acid, glyoxylic acid, citric acid, malic acid, maleic acid, pyrrolidone carboxylic acid, tartaric acid, succinic acid, levulinic acid, lactic acid, malonic acid, glycolic acid, glutaric acid, adipic acid, fumaric acid, etc., and these may be used alone or in combination of two or more.

[0041] The acid content is preferably in the range of 0.1 to 7% by weight, more preferably in the range of 0.5 to 5% by weight. If it is less than 0.1% by weight, it becomes difficult to obtain the effect of lowering the alkalinity of the first agent (partially neutralizing the alkaline agent), and if the mixing ratio of the second agent is increased to increase the amount of neutralization, the content of the oxidation dye in the mixed solution decreases, and the desired dyeing cannot be obtained. If it exceeds 7% by weight, the alkalinity of the system when the first agent and the second agent are mixed decreases drastically, and stable color development cannot be obtained.

[0042] The first and second agents according to the present invention can be used in various dosage forms such as liquid, gel, cream, etc., and are used by mixing the first and second agents. The mixing ratio of the first and second agents is usually about 1:1 to 1:3 by weight.

[0043] The pH value of the system when the first and second agents are mixed is not particularly limited as long as it exerts the effects of the present invention; however, from the viewpoint of dyeing lightened hair or gray hair due to bleaching of melanin pigment to a dark color close to black hair, a pH of 6 to 11 is preferable, and a pH of 7 to 10 is more preferable.

[0044] The present invention will be explained below by showing examples of formulations and examples that meet the conditions of the present invention and comparative examples that do not meet the conditions by their application methods. The amounts of the formulations shown in the examples are expressed in weight % unless otherwise specified. In addition, alkalinity as an index of properties refers to the number of mL of 0.1 mol / L hydrochloric acid solution required to neutralize 1 g of sample, and acidity refers to the number of mL of 0.1 mol / L sodium hydroxide solution required to neutralize 1 g of sample.

[0045] [Table 1]

[0046] [Table 2]

[0047] [Table 3]

[0048] [Table 4]

[0049] The pH values ​​in Tables 1 to 4 were measured using a pH meter (F-52, manufactured by Horiba, Ltd.), and the alkalinity and acidity shown in Tables 1 and 2 were measured using an automatic potentiometric titrator (AT-710, manufactured by Kyoto Electronics Manufacturing Co., Ltd.). The alkalinity values ​​in Tables 3 and 4 are theoretical values ​​calculated from the measurements in Tables 1 and 2, because the alkalinity is consumed when the first and second agents are mixed.

[0050] From Table 3, it can be seen that the pH values ​​of Comparative Example 2 and Comparative Example 3 are almost the same as Comparative Example 1, but the alkalinity is lower, so it is considered that the burden on hair is reduced. Moreover, the pH values ​​and alkalinity of Comparative Examples 4, 5, and 6 are lower than those of Comparative Examples 1, 2, and 3, respectively, so it is considered that the burden on hair is further reduced.

[0051] From Table 4, it can be seen that the pH values ​​of Examples 2 and 3 are almost the same as those of Example 1, but the alkalinity is lower, so the burden on hair is thought to be reduced. Moreover, the pH values ​​and alkalinity of Examples 4, 5, and 6 are lower than those of Examples 1, 2, and 3, respectively, so it is thought that the burden on hair is further reduced, and the oxidative hair dye of the present invention can be used in a way that reduces the burden on hair.

[0052] Next, using the chemicals shown in Tables 3 and 4, dye four types of hair strands of different brightness (see "Hair Dyeing Method" below), and compare the abilities of the chemicals as hair dyes based on their dye absorption. [Hair dyeing method] Hair bundles (yak hair (level 20), level 15 human hair, level 10 human hair, level 5 human hair) manufactured by George Matai Japan Co., Ltd., 1.2 g per strand, 120 mm long, were used. A mixture of the first agent shown in Table 1 and the second agent shown in Table 2, prepared in the ratios shown in Tables 3 and 4, was applied at 2 g per strand of hair bundle, and then left at 30°C for 15 or 30 minutes. The hair was then washed with warm water, shampooed, and treated with a conditioner to complete the dyeing process. Level 15 human hair, level 10 human hair, and level 5 human hair are human hairs with brightness levels of 15, 10, and 5, respectively, measured on our tone scale (a level scale created by Tamarikaku Co., Ltd.), and the brightness of the yak hair was level 20.

[0053] Here, our tone scale is a 15-level brightness number system, with the starting point being level 4, which represents the darkness of Japanese black hair, and the brightness of white being level 20. Below are the results of determining which scale numbers (4 to 20) of our tone scale (a nylon scale) correspond (match or are most similar) to which color name in the JIS color name book (based on JIS Z 8102). [Table 5]

[0054] [Test to confirm dark hair color close to black hair] For each hair bundle that had been dyed as described above, it was confirmed using the JIS color book whether it had been dyed a dark color close to black (JIS color book lightness 3.5 or less, chroma 3 or less). ○: According to the JIS color book, "Lightness 3.5 or less, chroma 3 or less." ×: The above conditions are not met.

[0055] [Table 6]

[0056] [Table 7]

[0057] From Table 6, it can be seen that with the formulations of the oxidative hair dyes of Comparative Examples 1 to 8, when the hair brightness becomes lighter, or when the dye concentration (the concentration of the oxidative dye in the total mixture of the first and second agents) becomes lower, or when the time required for dyeing is shortened (the usual 30 minutes left after application of the agent is shortened by 15 minutes), it tends to become more difficult to dye hair in a dark tone close to black hair (brightness of 3.5 or less, saturation of 3 or less in the JIS color book). On the other hand, from Table 7, it can be seen that when the oxidative hair dye compositions of the present invention according to Examples 1 to 8 are used, even if the lightness of the hair becomes lighter, or the dye concentration becomes lower to a certain extent, or even if the time required for dyeing is shortened to a certain extent, the hair is dyed in a dark tone close to black hair (lightness of 3.5 or less and saturation of 3 or less in the JIS color name book). In other words, it can be confirmed that even under conditions unfavorable for dyeing due to damaged hair, the composition has the effect of dyeing light hair or gray hair in a dark tone close to black hair due to bleaching of melanin pigment.

[0058] [Brightness verification test] In order to more strictly evaluate the lightness of each hair bundle that had been dyed as described above, we measured the lightness of each using our tone scale. The results of these measurements are shown in Tables 8 and 9. When dyeing hair that has differences in lightness, it is difficult to perfectly match the lightness after dyeing, but if the hair is dyed a dark color tone close to black (lightness 3.5 or less, chroma 3 or less in the JIS color name book) and the lightness difference (level difference) is kept to less than 2 on our tone scale, the lightness difference becomes very inconspicuous, resulting in a finish without large color variations due to lightness differences (color variations due to lightness differences are not noticeable).

[0059] [Table 8]

[0060] [Table 9]

[0061] As shown in Table 8, in Comparative Examples 2 to 8 (agents for damaged areas), when hair with a lightness level of 15 or higher was dyed, the lightness level was 6 or higher, except for Comparative Example 4. If the dyed lightness level (level 4) of Comparative Example 1, which has the lowest lightness, for level 5 hair is used as the standard, the difference in lightness from this standard is 2 levels or more (underlined parts in the table), which means that the lightness is not uniform and an unnatural feeling can occur.

[0062] In contrast, in Examples 2 to 8 (medicines for damaged areas) shown in Table 9, when the dyed hair brightness (level 4) of level 5 hair in Example 1, which has the lowest brightness, is used as the standard, in all Examples, the dyed hair results in a brightness of less than level 2. As described above, this, combined with the fact that the hair is dyed in a dark color tone close to black hair (brightness 3.5 or less, saturation 3 or less in the JIS color name book), makes the brightness difference very difficult to notice, resulting in a finish without large color variation due to brightness difference (color variation due to brightness difference is not noticeable).

[0063] [Test to check color variation] When dyed in a dark color tone close to black hair (JIS color name book lightness 3.5 or less, saturation 3 or less) and the lightness difference (level difference) is suppressed to less than 2 in our tone scale, the finish will be free of large color variations due to lightness differences (color variations due to lightness differences are not noticeable), but even in this case, theoretically, the difference in color tone may be noticeable. This tendency becomes stronger as lightness and saturation increase, and it is considered that when the difference in color tone is noticeable, if the hue system is different, it may cause discomfort, which may greatly affect the hair dyeing result. Therefore, for each hair bundle subjected to the above hair dyeing treatment, the difference in color tone between Comparative Examples 2 to 8 and Comparative Example 1, and the difference in color tone between Examples 2 to 8 and Example 1 were visually evaluated on the following four levels, and the results are shown in Tables 10 and 11. The difference in color tone here refers to a comprehensive evaluation of the difference in color tone (balance of lightness and saturation) and the difference in hue (unnaturalness). ◎: No noticeable difference in color tone, no discomfort ○: The color tone is slightly different, but it doesn't feel strange. △: The color tone is slightly different and feels a bit strange. ×: The color tone is completely different or slightly different, causing a strong sense of incongruity.

[0064] [Table 10]

[0065] [Table 11]

[0066] From Table 10, it can be said that, when Comparative Example 1 is used as a standard, Comparative Examples 2 to 8 (drugs for damaged areas) tend to show differences in the dyed hair color when the lightness of the hair becomes brighter or the dye concentration (the concentration of the oxidative dye in the total mixture of the first and second agents) becomes lower. On the other hand, when Example 1 is used as a standard, Examples 2 to 8 shown in Table 11 show hair dyeing results similar to Example 1, and it was confirmed from the viewpoint of variation in color tone (tone and hue) that they have the effect of dyeing lightened hair and gray hair that has been bleached of melanin pigment in a dark tone close to black hair without large color variation.

[0067] As can be seen from Tables 6 and 7, which show the results of the test to confirm a dark color tone close to black hair, Tables 8 and 9, which show the results of the test to confirm the lightness, and Tables 10 and 11, which show the results of the test to confirm the variation in color tone, by blending the oxidative hair dyes of Examples 1 to 8 according to the present invention, even hair with a lightness difference can be dyed a dark color tone close to black hair, achieving the desired lightness while suppressing the lightness difference, and also suppressing the variation in color tone (variation in color tone and hue), and it can be seen that this has a superior effect to the blends of the oxidative hair dyes of Comparative Examples 1 to 8.

[0068] Also, from Tables 7, 9, and 11, it can be seen that stable dyeing can be achieved even when treatment is performed under dyeing conditions that take damaged hair into consideration, such as reducing the amount of alkali by changing the mixing ratio of the first and second agents from 1:1 to 1:2-3, reducing the usual leaving time of 30 minutes to half (15 minutes), using an agent containing an acid (phosphoric acid in the above example) as the second agent, and making the mixed agent of the first and second agents closer to neutral. Of course, for example, if the second agent does not contain an acid and the mixed agent of the first and second agents is not made closer to neutral, the conditions are more favorable for dyeing, and it is clear that more stable dyeing can be achieved by performing treatment under conditions that do not take such damaged hair into consideration.

[0069] The recipe for Example 1 above is designed to dye yak hair dark gray-purple (color name "5P 3.5 / 3" in the JIS color book), and the recipe for Example 8, which is the condition most likely to cause color change among Examples 2 to 8, dyes yak hair dark gray-blue-purple (color name "10PB 3 / 3" in the JIS color book), and no significant change in the dyeing results (color tone, etc.) is observed between Examples 1 to 8.

[0070] It is to be noted that the present invention is not limited to the above-described embodiment, and can be modified in various ways without departing from the spirit and scope of the present invention. For example, the following modifications can be mentioned.

[0071] In the above embodiment, the case where the hair treatment agent is a two-component type has been described, however, the hair treatment agent is not limited to a two-component type and may be a multi-component type, for example, a three-component or more component type.

[0072] It goes without saying that the modified examples given in this specification may be combined as appropriate.

Claims

1. An oxidation hair dye comprising a first agent containing an oxidation dye and an alkali agent and a second agent containing an oxidizing agent, The first agent and the second agent are mixed in a weight ratio of 1:1 to 1:3, The oxidation dye is contained in an amount of 0.1 to 7.0% by weight based on the total weight of the first and second agents, The oxidation hair dye uses paramethylaminophenol and / or a salt thereof and 2,2'-[(4-aminophenyl)imino]bisethanol and / or a salt thereof as precursors, and uses resorcin, metaaminophenol and 5-aminoorthocresol as couplers.

2. 2. The oxidation hair dye composition according to claim 1, further comprising para-aminophenol as a precursor.

3. 3. The oxidative hair dye composition according to claim 1, further comprising at least one alkaline agent selected from the group consisting of ammonia and monoethanolamine.

4. 4. The oxidation hair dye composition according to claim 3, which contains, as a precursor, neither paraphenylenediamine nor toluene-2,5-diamine or its salts.

5. 5. The oxidative hair dye composition according to claim 4, which is used to dye hair from which melanin has been removed or gray hair to a dark color close to black hair.

Images