Chinese gall plant hair dye with low reducing agent content and hair dyeing method thereof

Abstract

The invention discloses a Chinese gall plant hair dye with low reducing agent content and a hair dyeing method thereof, and the hair dyeing method comprises the following steps: S1, uniformly smearing the Chinese gall plant hair dye with low reducing agent content on the surface of hair by using a dyeing brush, coating with a preservative film, and keeping for 10-30 minutes at the temperature of 20-50 DEG C; s2, after the treatment in the step S1 is finished, removing the preservative film, rinsing the surface of the hair cleanly, and wiping off floating water; s3, taking a color developing agent, uniformly smearing the color developing agent on the hair treated in the step S2 by using a dyeing comb, coating with a preservative film, and keeping mordanting color development for 5-8 minutes at room temperature; s4, after the treatment in the step S3 is finished, removing the preservative film, rinsing the hair, and wiping off floating water; and S5, repeating the steps S1 to S4 for 1-2 times. According to the hair dyeing method, the use amount of the reducing agent in the gallnut plant hair dye can be effectively reduced, the hair dyeing effect is guaranteed mainly through multiple mordanting, and the content of the reducing agent in the gallnut plant hair dye formula can be reduced to a great extent.

Description

Technical Field

[0001] The invention relates to the technical field of hair dyeing, and in particular to a gallnut plant hair dye with low reducing agent content and a hair dyeing method thereof. Background Art

[0002] People have developed hair dyes from various sources of dyes for the purpose of pursuing beauty or covering gray hair, but these hair dyes mostly rely on dyes directly attached to the hair for dyeing, and often have problems such as insufficient dyeing rate and low color fastness. Since the advent of synthetic oxidative hair dyes, they have been rapidly promoted worldwide for their advantages such as easy dyeing, high color fastness, and convenient use. However, in recent years, more and more studies have shown that synthetic oxidative hair dyes containing aniline substances have clear risks such as sensitization and carcinogenicity, as well as potential risks such as teratogenicity. Today, when the safety of beauty and hairdressing daily chemical products is increasingly concerned, the research and development of healthy and mild hair dyes has become a hot spot in the hair dyeing industry.

[0003] As a natural dye, plant hair dyes have attracted extensive attention from the industry and consumers due to their high safety. The dyeing principle of plant hair dyes such as gallnut is to rely on the redox reaction of reducing agents with disulfide bonds in the hair to open the hair scales, allowing the polyphenol plant dye molecules with larger molecular weight to enter the hair, form color complexes with the metal ions of the developer to show the color, and form a certain combination with the anion groups such as carboxyl groups on the hair keratin molecules through the metal cations to achieve the durability of the dyeing. The dyeing process of plant hair dyes occurs inside the hair, and the plant pigments and metal ions are complexed very quickly, so the dyeing rate, color fastness, and hair dyeing effect have reached the level of synthetic oxidative hair dyes.

[0004] In the dyeing process of this type of plant hair dye, the speed at which dye molecules penetrate the hair scales into the inner cortex of the hair is a key factor limiting the dyeing effect, dyeing speed, and color fastness of the hair dye. Reducing agents need to be added to the formula of plant hair dyes to open the hair scales through their chemical action to accelerate the penetration of dye molecules. Studies have shown that the content of reducing agents has a significant positive correlation with the dyeing effect and dyeing efficiency. In order to ensure the dyeing effect, plant hair dye formulas often contain up to about 10% of reducing agents such as L-cysteine, L-cysteine ​​hydrochloride, and ammonium thioglycolate.

[0005] While a large amount of reducing agents in plant hair dye formulas can bring ideal hair dyeing effects, they can also easily damage the hair and act on the scalp, causing irritation to the scalp. Reducing the content of reducing agents in the formula can greatly reduce the negative effects it brings and improve the safety of the product. However, with the current one-time hair dyeing process, reducing the content of reducing agents will greatly affect the hair dyeing effect. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a gallnut plant hair dye with a low reducing agent content and a hair dyeing method matched therewith. The application of the hair dye and the new process greatly reduces the content of the reducing agent, greatly alleviates the negative effects brought by the high content of the reducing agent, and can ensure the hair dyeing effect, and can effectively reduce the dependence of the hair dyeing effect on the hair dyeing temperature and hair dyeing time.

[0007] To achieve the above purpose, the present invention provides a gallnut plant hair dye with low reducing agent content, which comprises the following components in parts by mass: 20-30 parts of gallnut water extract, 0-10 parts of clove water extract, 0-10 parts of terminalia chebula water extract, 0.5-1 part of reducing agent, 1-2 parts of sodium dodecyl sulfate, 2-4 parts of 1,3-butanediol, 1-2 parts of sodium hydroxymethyl cellulose, 1 part of phenoxyethanol, and the balance is water, totaling 100 parts.

[0008] Furthermore, the Galla chinensis water extract is prepared by the following method:

[0009] S1: Weigh 5-10 parts of gallnut powder and mix them evenly with 90-95 parts of water, and let them stand for 24-48 hours;

[0010] S2: placing the mixed solution after the static treatment in step S1 in a constant temperature water bath oscillator and oscillating and extracting at 80-85°C for 1-2 hours;

[0011] S3: centrifuging the mixed solution after the oscillation extraction in step S2 at a speed of 4000-4500 rpm for 30-40 minutes;

[0012] S4: taking the supernatant after the centrifugation in step S3, which is the water extract of Galla chinensis.

[0013] Furthermore, the clove water extract is prepared by the following method:

[0014] S1: Weigh 5-10 parts of clove powder and mix them evenly with 90-95 parts of water, and let them stand for 24-48 hours;

[0015] S2: placing the mixed solution after the static treatment in step S1 in a constant temperature water bath oscillator and oscillating and extracting at 80-85°C for 1-2 hours;

[0016] S3: centrifuging the mixed solution after the oscillation extraction in step S2 at a speed of 4000-4500 rpm for 30-40 minutes;

[0017] S4: Take the supernatant after the centrifugation in step S3, which is the clove water extract.

[0018] Furthermore, the terminalia chebula water extract is prepared by the following method:

[0019] S1: Weigh 5-10 parts of Terminalia chebula powder and mix them evenly with 90-95 parts of water, and let them stand for 24-48 hours;

[0020] S2: placing the mixed solution after the static treatment in step S1 in a constant temperature water bath oscillator and oscillating and extracting at 80-85° C. for 1-2 hours;

[0021] S3: centrifuging the mixed solution after the oscillation extraction in step S2 at a speed of 4000-4500 rpm for 30-40 minutes;

[0022] S4: taking the supernatant after the centrifugation in step S3, which is the terminalia chebula water extract.

[0023] Furthermore, the reducing agent is selected from sodium thioglycolate, ammonium thioglycolate, L-cysteine, L-cysteine ​​hydrochloride, N-acetylcysteine, potassium thiocyanate, sodium sulfite, and sodium nitrite.

[0024] The present invention also provides a method for dyeing hair using the gallnut plant hair dye with low reducing agent content, comprising the following steps:

[0025] S1: applying the gallnut plant hair dye with low reducing agent content evenly on the hair surface with a dye brush, covering with plastic wrap, and keeping at a temperature of 20-50° C. for 10-30 minutes;

[0026] S2: After the treatment in step S1 is completed, remove the plastic wrap, rinse the hair surface, and wipe off the floating water;

[0027] S3: Take a developer, apply the developer evenly on the hair treated in step S2 using a dye comb, cover with plastic wrap, and keep at room temperature for 5-8 minutes for mordanting;

[0028] S4: After the treatment in step S3 is completed, the plastic wrap is removed, the hair is rinsed clean, and the floating water is wiped off;

[0029] S5: Repeat steps S1-S4 1-2 times.

[0030] Furthermore, in the step S1, the temperature is maintained at 20-50° C. for 20-30 minutes.

[0031] Furthermore, the developer comprises the following components in parts by mass: 3.5-7.5 parts of ferrous salt, 0.01-0.05 parts of L(+)-ascorbic acid, 3-5 parts of polyquaternium-7, and the remainder is water, totaling 100 parts.

[0032] Furthermore, in step S3, the mordanting is maintained at room temperature for 5 minutes.

[0033] Furthermore, in step S5, when step S1 is repeated, the temperature is maintained at 20-50° C. for 10 minutes.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] First, the multiple dyeing process studied in the present invention replaces the existing one-time hair dyeing method, and can reduce the amount of reducing agent in the gallnut plant hair dye from 10% to 0.5-1%. Relying on this dyeing method can not only ensure the hair dyeing effect, but also minimize the irritation to the scalp caused by the reducing agent in the gallnut plant hair dye formula.

[0036] Secondly, according to the results of volunteer subjects, the hair dyeing method of the present invention has an ideal effect when dyeing hair with a gallnut plant hair dye with a low reducing agent content, is less affected by the dyeing temperature and dyeing time, has a stable effect, and has no obvious tingling sensation on the scalp.

[0037] Thirdly, the hair dyeing method of the present invention effectively overcomes the problem of poor hair dyeing effect caused by the difficulty of dye molecules entering the hair when the reducing agent content of the gallnut plant hair dye is low by increasing the number of hair dyeing times. Compared with prolonging the residence time of the colorant on the hair, the new process of repeated dyeing provided by the present invention can more obviously improve the hair dyeing effect of the gallnut plant hair dye with low concentration of reducing agent.

[0038] Fourthly, the present invention relies on repeated dyeing to ensure the hair dyeing effect, which can greatly reduce the reducing agent content in the gallnut plant hair dye formula, thereby effectively reducing the damage to the hair and the scalp irritation problem that is easily caused during the hair dyeing process.

[0039] Fifthly, the hair dyeing method provided by the present invention does not require a high content of reducing agent in the gallnut plant hair dye, and only a small amount of reducing agent needs to be added to obtain an ideal hair dyeing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a sample picture of undyed white yak hair;

[0041] Figure 2 This is a picture showing the effect of dyeing the hair sample in Example 1;

[0042] Figure 3 This is a picture showing the effect of dyeing the hair sample in Example 2;

[0043] Figure 4 This is a picture showing the effect of dyeing the hair sample in Example 3;

[0044] Figure 5 This is a picture showing the effect of dyeing the hair sample in Example 4;

[0045] Figure 6 This is a picture showing the effect of dyeing the hair sample in Example 5;

[0046] Figure 7 This is a picture showing the effect of dyeing the hair sample in Example 6;

[0047] Figure 8 This is a picture showing the effect of dyeing the hair sample in Example 7;

[0048] Fig. 9 This is a picture showing the effect of dyeing the hair sample in Example 8;

[0049] Fig.10 This is a picture of the effect of dyeing the hair sample of Comparative Example 1;

[0050] Fig.11 This is a picture of the effect of dyeing the hair sample of Comparative Example 2;

[0051] Fig.12 This is a picture of the effect of dyeing the hair sample of Comparative Example 3. DETAILED DESCRIPTION

[0052] The following is a detailed description of the implementation of the present invention in conjunction with the implementation cases, but they do not constitute a limitation of the present invention and are only given as examples. At the same time, the advantages of the present invention will become clearer and easier to understand through the description.

[0053] The present invention provides a method for dyeing hair using a gallnut plant hair dye with a low reducing agent content, comprising the following steps:

[0054] S1: Apply the gallnut plant hair dye evenly on the hair surface with a dye brush, cover with plastic wrap, and keep at a temperature of 20-50°C for 20-30 minutes;

[0055] S2: After the treatment in step S1 is completed, remove the plastic wrap, rinse the hair surface, and wipe off the floating water;

[0056] S3: Take a developer, apply the developer evenly on the hair treated in step S2 using a dye comb, cover with plastic wrap, and keep at room temperature for 5-8 minutes for mordanting;

[0057] S4: After the treatment in step S3 is completed, the plastic wrap is removed, the hair is rinsed clean, and the floating water is wiped off;

[0058] S5: Repeat steps S1-S4 1-2 times, and keep the time for repeating step S1 for 10 minutes.

[0059] The formulas of the gallnut plant hair dyes with low reducing agent content according to various embodiments of the present invention are shown in Table 1.

[0060] Table 1 Formula of each embodiment of the gallnut plant hair dye

[0061]

[0062] The gallnut water extract is prepared by the following method:

[0063] S1: Weigh 5-10 parts of gallnut powder and mix them evenly with 90-95 parts of water, and let them stand for 24-48 hours;

[0064] S2: placing the mixed solution after the static treatment in step S1 in a constant temperature water bath oscillator and oscillating and extracting at 80-85°C for 1-2 hours;

[0065] S3: centrifuging the mixed solution after the oscillation extraction in step S2 at a speed of 4000-4500 rpm for 30-40 minutes;

[0066] S4: taking the supernatant after the centrifugation in step S3, which is the water extract of Galla chinensis.

[0067] The clove water extract is prepared by the following method:

[0068] S1: Weigh 5-10 parts of clove powder and mix them evenly with 90-95 parts of water, and let them stand for 24-48 hours;

[0069] S2: placing the mixed solution after the static treatment in step S1 in a constant temperature water bath oscillator and oscillating and extracting at 80-85°C for 1-2 hours;

[0070] S3: centrifuging the mixed solution after the oscillation extraction in step S2 at a speed of 4000-4500 rpm for 30-40 minutes;

[0071] S4: Take the supernatant after the centrifugation in step S3, which is the clove water extract.

[0072] The terminalia chebula water extract is prepared by the following method:

[0073] S1: Weigh 5-10 parts of Terminalia chebula powder and mix them evenly with 90-95 parts of water, and let them stand for 24-48 hours;

[0074] S2: placing the mixed solution after the static treatment in step S1 in a constant temperature water bath oscillator and oscillating and extracting at 80-85°C for 1-2 hours;

[0075] S3: centrifuging the mixed solution after the oscillation extraction in step S2 at a speed of 4000-4500 rpm for 30-40 minutes;

[0076] S4: taking the supernatant after the centrifugation in step S3, which is the terminalia chebula water extract.

[0077] The reducing agent in each embodiment is selected from sodium thioglycolate, ammonium thioglycolate, L-cysteine, L-cysteine ​​hydrochloride, N-acetylcysteine, potassium thiocyanate, sodium sulfite, and sodium nitrite.

[0078] The developer formulations of various embodiments of the present invention are shown in Table 2.

[0079] Table 2: Developer formulations for each example

[0080]

[0081] White yak hair is used as the sample material to be dyed. The process conditions of the dyeing methods of Examples 1-8 are detailed in Table 3 below, where:

[0082] Hair dyeing temperature: refers to the temperature at which the gallnut plant hair dye stays during each hair dyeing process;

[0083] First hair dyeing time: refers to the time the gallnut plant hair dye stays during the first hair dyeing process;

[0084] Second hair dyeing time: refers to the time the gallnut plant hair dye stays during the second hair dyeing process;

[0085] The third hair dyeing time: refers to the time that the gallnut plant hair dye stays during the third hair dyeing process.

[0086] Table 3 Dyeing process conditions of each embodiment

[0087]

[0088] The specific hair dyeing methods of various embodiments are the same except for the above conditions. Each hair dyeing process includes a mordanting process, and the specific process conditions are mordanting at room temperature for 5-8 minutes.

[0089] In order to intuitively demonstrate the hair dyeing effect and color fastness of each embodiment, two commercially available synthetic oxidative hair dyes were selected for hair dyeing as Comparative Examples 1 and 2, and a gallnut plant hair dye with a high reducing agent content was selected for hair dyeing under optimal conditions as Comparative Example 3. Comparative Examples 1, 2, and 3 are described below:

[0090] Comparative Example 1:

[0091] 1. Hair dye brand: Schwarzkopf Yiran hair dye cream

[0092] 2. Hair dyeing temperature: room temperature

[0093] 3. Operation steps: follow the product instructions

[0094] (1) Take equal amounts of A and B in a container, mix and stir evenly for later use.

[0095] (2) Use a brush to evenly apply the stirred hair dye onto the hair surface.

[0096] (3) Wrap the hair treated in step (2) with plastic wrap and place at room temperature for 30 minutes.

[0097] (4) After the timing of step (3) is over, rinse the hair with clean water and let it dry naturally.

[0098] Comparative Example 2:

[0099] 1. Hair dye brand: Hanbang Wubeizi Color Dye

[0100] 2. Hair dyeing temperature: room temperature

[0101] 3. Hair dyeing steps: follow the product instructions

[0102] (1) Take equal amounts of A and B in a container, mix and stir evenly for later use.

[0103] (2) Use a brush to evenly apply the stirred hair dye onto the hair surface.

[0104] (3) Wrap the hair treated in step (2) with plastic wrap and place at room temperature for 30 minutes.

[0105] (4) After the timing of step (3) is over, rinse the hair with clean water and let it dry naturally.

[0106] Comparative Example 3:

[0107] 1. The formulas of the gallnut plant hair dye and developer involved in Comparative Example 3 are detailed in Tables 4 and 5 below.

[0108] Table 4 Comparative Example 3 Galla chinensis plant hair dye formula

[0109] Components Content (mass fraction) / % Components Content (mass fraction) / % Gallnut water extract 30 Cocamidopropyl Betaine 1 Clove water extract 10 1,3-Butanediol 4 Terminalia chebula water extract 10 Sodium Carboxymethyl Cellulose 1 reducing agent 9 Phenoxyethanol 1 Sodium Lauryl Sulfate 1 Deionized water 33

[0110] Table 5 Comparative Example 3 Developer Formula

[0111] Components Content (mass fraction) / % Ferrous salt 4.5 L(+)-Ascorbic Acid 0.05 Polyquaternium-7 5 Deionized water 90.45

[0112] 2. Hair dyeing process:

[0113] (1) Use a dye brush to evenly apply the gallnut plant hair dye on the hair surface and cover it with plastic wrap.

[0114] (2) Stain at 35°C for 45 min.

[0115] (3) After the timing of step (2) is over, rinse the hair with clean water and wipe off the floating water on the surface.

[0116] (4) After step (3), apply the developer evenly to the hair surface and cover it with plastic wrap.

[0117] (5) Leave the color developer at room temperature for 5 minutes.

[0118] (6) After the timing of step (5) is over, rinse the hair with clean water and let it dry naturally.

[0119] After the hair dyed in each embodiment and comparative example is dried, relevant data are tested, the dyeing effect is observed and photographed, and multiple groups of test data and pictures of the dyed hair are used to intuitively and comprehensively demonstrate the hair dyeing effect of each embodiment and comparative example. The following will describe in detail each group of test data of the dyed hair.

[0120] Hair dyeing effect:

[0121] The hair dyeing effect is reflected by pictures and data. The actual effect pictures of hair dyeing of the embodiment and the comparative example are shown in Figure 1-12 .

[0122] 1. Color difference value:

[0123] Sucolor's SC-20 ultra-high precision colorimeter was used to test the L, a, and b values ​​of the dyed hair in Examples 1-8 and Comparative Examples 1-3. The L value represents the brightness of the color being measured. The larger the L value, the whiter the color. L=100 represents pure white. Conversely, the smaller the L value, the darker the color. L=0 represents pure black. The a value represents the change from green to gray and then to red. A negative a value represents that the color is more inclined to green, and a positive a value represents that the color is more inclined to red. 0 represents 50% gray. The b value represents the change from blue to gray and then to yellow. A negative b value represents that the color is more inclined to blue, and a positive b value represents that the color is more inclined to yellow. 0 represents 50% gray. The △E value is obtained by performing a difference fitting calculation on the L, a, and b values ​​measured before and after the sample is dyed. The △E value is used to represent the change in hair color before and after dyeing. The calculation formula is:

[0124]

[0125] Among them, ΔL represents the change of the L value of the hair before and after dyeing, Δa represents the change of the a value of the hair before and after dyeing, and Δb represents the change of the b value of the hair before and after dyeing. The larger the ΔE, the greater the color difference before and after hair dyeing. The hair dyes involved in the present invention are all black hair dyes. By comparing the L value and ΔE value of the experimental hair, the quality of the dyeing effect of the hair dye can be intuitively indicated through data.

[0126] Table 6 Hair dyeing sample data of each embodiment and comparative example

[0127]

[0128] As can be seen from the table, the ΔL and ΔE of the eight examples are similar to those of the comparative example, indicating that the hair dyeing method provided by the present invention can achieve an ideal hair dyeing effect even if the reducing agent content in the hair dye is as low as 0.5-1%. The hair dyed by the eight examples is observed with the naked eye, and there is no significant difference in the depth of hair color and glossiness between the eight examples and the hair dyed by the commercially available synthetic oxidative hair dye.

[0129] 2. Tensile strength:

[0130] The tensile strength of the dyed hair of each embodiment and comparative example was measured using a tensile meter, and the magnitude thereof was used to measure the degree of damage to the experimental hair by the hair dye used in each embodiment and comparative example. The greater the tensile strength of the experimental hair, the less the degree of damage. For each group of experimental samples, 30 dyed hairs were taken to measure the tensile strength, and the average value was taken.

[0131] Table 7 Tensile strength of hair after dyeing in each embodiment and comparative example

[0132]

[0133] The data in Table 7 show that compared to the undyed blank control hair, the tensile strength of the hair after dyeing in each embodiment and comparative example all decreases, indicating that the hair dye used in each embodiment and comparative example has different degrees of damage to the hair. Except for Example 4 and Example 7, the tensile strength of each embodiment is greater than that of the commercially available synthetic oxidative hair dye, which indicates that when the low-concentration reducing agent gallnut plant hair dye uses the present invention to dye hair, the degree of damage to the hair is similar to that of the commercially available synthetic oxidative hair dye, or even less than that of the commercially available synthetic oxidative hair dye. The tensile strength of the hair after dyeing in Comparative Example 3, i.e., the gallnut plant hair dye with high reducing agent content, is the lowest, indicating that the degree of damage to the hair is the greatest.

[0134] 3. Washing fastness:

[0135] Washing fastness is one of the indicators to measure the color fastness of hair dye after dyeing. It reflects the adhesion of the dye on the hair, indicates the durability of the coloring, and is an important performance indicator. It is expressed by the difference in color difference values ​​after washing the dyed hair several times. The larger the difference in color difference value, the lower the washing fastness of the hair dye and the worse the durability of the coloring. The specific operation is: after dyeing, measure the L, a, and b values ​​of the hair, calculate the color difference value △E, wash 25 times, measure the L, a, and b values ​​of the hair again, calculate the color difference value △E, subtract the color difference value △E of the hair before washing from the color difference value △E after washing 25 times to obtain the difference in color difference value of the hair before and after dyeing with the hair dye of each embodiment and comparative example. The larger the difference in color difference value, the worse the washing fastness. The washing method is similar to daily hair washing: wet the hair to be tested with clean water, take an appropriate amount of shampoo on the hair to be tested, rub the hair to be tested evenly for 1 minute, rinse with clean water, and dry naturally. This is one wash, and repeat this 25 times. The results are shown in Table 8.

[0136] Table 8 Washing fastness of each embodiment and comparative example

[0137]

[0138] As can be seen from Table 8, the color difference before and after washing of Comparative Example 1, a commercially available oxidative hair dye, is the largest, and its washing fastness is the worst. The low-reducing-agent gallnut plant hair dyes of Examples 1-8 use multiple dyeing processes and the gallnut plant hair dye with a high reducing agent content in Comparative Example 3 have no significant difference in washing fastness after dyeing with Comparative Example 2, another commercially available oxidative hair dye. After dyeing using the process of the present invention, its washing fastness is excellent, reaching or even better than the level of commercially available synthetic oxidative hair dyes. The color difference change value of all examples after dyeing hair is less than 2 after washing 25 times, and this degree of change is difficult to be clearly perceived by the naked eye.

[0139] The above is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention. Any changes or replacements that can be easily thought of by any technician familiar with the field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention, and the rest that are not described in detail belong to the prior art.

Claims

1. A gallnut plant hair dye with low reducing agent content, characterized in that: The invention comprises the following components by weight: 20-30 parts of gallnut water extract, 0-10 parts of clove water extract, 0-10 parts of terminalia chebula water extract, 0.5-1 parts of reducing agent, 1-2 parts of sodium dodecyl sulfate, 2-4 parts of 1,3-butanediol, 1-2 parts of sodium hydroxymethylcellulose, 1 part of phenoxyethanol, and the balance is water, totaling 100 parts.

2. The gallnut plant hair dye with low reducing agent content according to claim 1, characterized in that: The gallnut water extract is prepared by the following method: S1: Weigh 5-10 parts of gallnut powder and mix them evenly with 90-95 parts of water, and let them stand for 24-48 hours; S2: placing the mixed solution after the static treatment in step S1 in a constant temperature water bath oscillator and oscillating and extracting at 80-85°C for 1-2 hours; S3: centrifuging the mixed solution after the oscillation extraction in step S2 at a speed of 4000-4500 rpm for 30-40 minutes; S4: taking the supernatant after the centrifugation in step S3, which is the water extract of Galla chinensis.

3. The gallnut plant hair dye with low reducing agent content according to claim 1, characterized in that: The clove water extract is prepared by the following method: S1: Weigh 5-10 parts of clove powder and mix them evenly with 90-95 parts of water, and let them stand for 24-48 hours; S2: placing the mixed solution after the static treatment in step S1 in a constant temperature water bath oscillator and oscillating and extracting at 80-85°C for 1-2 hours; S3: centrifuging the mixed solution after the oscillation extraction in step S2 at a speed of 4000-4500 rpm for 30-40 minutes; S4: Take the supernatant after the centrifugation in step S3, which is the clove water extract.

4. The gallnut plant hair dye with low reducing agent content according to claim 1, characterized in that: The terminalia chebula water extract is prepared by the following method: S1: Weigh 5-10 parts of Terminalia chebula powder and mix them evenly with 90-95 parts of water, and let them stand for 24-48 hours; S2: placing the mixed solution after the static treatment in step S1 in a constant temperature water bath oscillator and oscillating and extracting at 80-85°C for 1-2 hours; S3: centrifuging the mixed solution after the oscillation extraction in step S2 at a speed of 4000-4500 rpm for 30-40 minutes; S4: taking the supernatant after the centrifugation in step S3, which is the terminalia chebula water extract.

5. The gallnut plant hair dye with low reducing agent content according to claim 1, characterized in that: The reducing agent is selected from sodium thioglycolate, ammonium thioglycolate, L-cysteine, L-cysteine ​​hydrochloride, N-acetylcysteine, potassium thiocyanate, sodium sulfite, and sodium nitrite.

6. A method for dyeing hair using the gallnut plant hair dye with low reducing agent content according to any one of claims 1 to 5, characterized in that: The steps include: S1: Apply the gallnut plant hair dye with low reducing agent content as claimed in any one of claims 1 to 5 evenly on the hair surface with a dye brush, cover with plastic wrap, and keep at a temperature of 20-50° C. for 10-30 minutes; S2: After the treatment in step S1 is completed, remove the plastic wrap, rinse the hair surface, and wipe off the floating water; S3: Take a developer, apply the developer evenly on the hair treated in step S2 using a dye comb, cover with plastic wrap, and keep at room temperature for 5-8 minutes for mordanting; S4: After the treatment in step S3 is completed, the plastic wrap is removed, the hair is rinsed clean, and the floating water is wiped off; S5: Repeat steps S1-S4 1-2 times.

7. The hair dyeing method according to claim 6, characterized in that: In the step S1, the temperature is maintained at 20-50° C. for 20-30 minutes.

8. The hair dyeing method according to claim 6, characterized in that: The developer comprises the following components by weight: 3.5-7.5 parts of ferrous salt, 0.01-0.05 parts of L(+)-ascorbic acid, 3-5 parts of polyquaternium-7, and the balance is water, which is 100 parts in total.

9. The hair dyeing method according to claim 6, characterized in that: In the step S3, the mordanting is maintained at room temperature for 5 minutes.

10. The hair dyeing method according to claim 6, characterized in that: In step S5, when step S1 is repeated, the temperature is maintained at 20-50° C. for 10 minutes.

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