A black hair dye based on plant extracts and a method of preparation

Abstract

This invention provides a black hair dye based on plant extracts and its preparation method. Effective components are extracted from plants such as rice roots, ginkgo leaves, arborvitae, rhubarb, cockscomb, chrysanthemum, mulberry, black tea, green tea, gentian, lichen, and catechu. It contains no harmful chemicals such as common paraphenylenediamine or ammonia. This hair dye enables even coloring of hair. The surfactant reduces the surface tension of the dye system, allowing the plant extracts and other components to disperse more evenly in the solution and better contact with the hair. During the dyeing process, it ensures that each hair strand fully absorbs the dyeing components, achieving a uniform coloring effect and avoiding uneven coloring. The color produced by this invention is natural and long-lasting, which is closely related to the synergistic effect of the plant extracts and the mordant ferrous sulfate. The hair dye of this invention performs better in maintaining color stability, allowing consumers to maintain their ideal hair color for a longer period.

Description

Technical Field

[0001] This invention relates to the field of essential technologies for human life, specifically to a black hair dye based on plant extracts and its preparation method. Background Technology

[0002] Currently, there are many types of hair dyes on the market, widely used in the hairdressing industry and in consumers' daily lives. However, these traditional hair dyes have many drawbacks. In terms of their impact on hair, the chemicals in most hair dyes damage the protein structure of the hair, leading to the loss of moisture and nutrients. This makes the hair dry, lacking in moisture, rough to the touch, and loses its original shine, appearing dull and lifeless. It also becomes less elastic, brittle, and prone to breakage when combing, seriously affecting the health and appearance of the hair. For example, ammonia, a common permanent hair dye, is highly alkaline and can open the hair cuticle, making it easier for the dye to penetrate. However, it also causes irreversible damage to the hair's protein structure, and long-term use will severely degrade hair quality.

[0003] In terms of irritation, some ingredients in hair dye, such as paraphenylenediamine, can easily trigger allergic reactions. Many consumers experience discomfort such as redness, swelling, and itching on their scalp after using hair dye; in severe cases, blisters and oozing may occur, affecting the normal physiological function of the scalp. Furthermore, the pungent odor of hair dye can also create an unpleasant experience for users. These odors usually come from volatile gases produced during the oxidation or other reactions of chemicals, such as ammonia. Not only are they pungent and unpleasant, but they can also irritate the respiratory tract, causing problems such as coughing and difficulty breathing.

[0004] More seriously, some hair dyes contain harmful chemicals, such as benzene compounds and heavy metals. Benzene compounds, as solvents, have potential carcinogenicity, and long-term exposure may increase the risk of cancer. Heavy metals such as lead and mercury, although present in low concentrations in hair dyes, can gradually accumulate in the hair and scalp with prolonged use. They can be absorbed into the body through the scalp, damaging the nervous system, circulatory system, kidneys, and other organs, thus affecting overall health. These problems mean that while traditional hair dyes meet consumers' hair-dyeing needs, they also pose potential health risks.

[0005] Therefore, a hair dye that does not contain irritating ingredients or harmful chemicals is needed. Summary of the Invention

[0006] This invention addresses the problem of irritating ingredients and harmful chemicals in hair dyes by providing a black hair dye based on plant extracts and its preparation method. The invention extracts effective components from plants such as rice roots, ginkgo leaves, arborvitae, rhubarb, cockscomb, chrysanthemum, mulberry, black tea, green tea, gentian, lichen, and catechu, combined with ferrous sulfate mordant. It is free of phenylenediamine, benzene compounds, and heavy metals. Using a pre-dyeing followed by mordant method, it achieves a natural hair color change during the dyeing process, resulting in good color and a natural, long-lasting color.

[0007] This invention provides a black hair dye based on plant extracts, which consists of hair dye agent A and hair dye agent B. Hair dye agent A contains plant extracts, which are obtained by adjusting the pH of rice roots and plant raw material A, stewing, dissolving, precipitating and separating, complexing and re-dissolving the precipitate, removing impurities, filtering, concentrating and drying. Plant ingredient A consists of any one or more of the following: ginkgo leaves, arborvitae, rhubarb, cockscomb flower, chrysanthemum, mulberry, black tea, green tea, gentian, lichen, and catechu; Hair dye B includes ferrous sulfate, emulsifiers, and surfactants.

[0008] The present invention discloses a black hair dye based on plant extracts. In a preferred embodiment, the plant extracts are obtained by reacting unsaturated phenolic acids from rice roots with flavonoids in plant raw material A, followed by reaction with amines and subsequent oxidative polymerization. The extracts are then complexed with ferrous sulfate to obtain oligomers. These oligomers undergo exchange reactions with disulfide bonds in hair keratin to form covalent bonds. The flavonoids include flavones, isoflavones, diflavones, and anthocyanins. The oligomers are indole derivatives and are macromolecular melanin. Plant extracts are solid; Hair dye Agent A also includes emulsifiers, surfactants, thioglycolic acid, and water; Black hair dye does not contain phenylenediamine, benzene compounds, or heavy metals.

[0009] The present invention discloses a black hair dye based on plant extracts. As a preferred embodiment, the hair dye A component comprises the following mass percentage composition: plant extracts: 1%~3.75%, cetearyl alcohol: 2.5%~5%, ethoxylated C16~18-ol: 1%~3%; hexadecyltrimethylammonium chloride: 0.5%~1%, oleyl alcohol: 0.5%~1%, propylene glycol: 1%~3%; PEG-40 hydrogenated castor oil: 0.5%~1%, thioglycolic acid: 1%~1.5%, polylysine: 0.1%~0.2%, disodium EDTA: 0.05%~1%, sodium sulfite: 0.1%~0.4%, ethanolamine: 0.1%~3%, and water: 76.15%~91.75%. The mass percentage composition of hair dye agent B is as follows: ferrous sulfate: 1%~3.75%, cetearyl alcohol: 3%~5%, ethoxylated C16~18-ol: 1%~3%, hexadecyltrimethylammonium chloride: 0.5%~1%, oleyl alcohol: 0.5%~1%, propylene glycol: 1%~3%, PEG~40 hydrogenated castor oil: 0.5%~1%, and water: 82.25%~92.5%.

[0010] This invention provides a method for preparing a black hair dye based on plant extracts, comprising the following steps: S1. Mix the plant raw materials and grind them to obtain plant powder. Dissolve the plant powder in water and adjust the pH value to 9-11. Add the extractant, boil and keep warm, filter to obtain the first solution. Use a precipitant to precipitate the first solution, and then use a cosolvent to complex and dissolve the precipitate. After the adsorbent adsorbs the impurities in the solution, filter, concentrate and dry to obtain the plant extract. The plant material consists of rice roots and plant material A, which is a substance containing flavonoids and / or isoflavones and / or diflavonoids and / or anthocyanins. The extractant is any one of the following: formaldehyde, acetaldehyde, propionaldehyde, sodium formaldehyde sulfoxylate, benzaldehyde, acetone, and cyclohexanone; The precipitant can be any one of the following: phenol, p-methylphenol, urea, and ammonia. The cosolvent is any one of the following: tartaric acid, tartrate, citric acid, and disodium EDTA; S2. Add the plant extract to water, heat and stir to dissolve, then add the surfactant and continue stirring. Then add any one or more of the following: humectant, reducing agent, solubilizer, pH adjuster B, chelating agent, and preservative. Add water again and continue heating and stirring. After mixing completely, let it cool naturally to obtain hair dye agent A. S3. Ferrous sulfate is mixed with any one or more of emulsifiers, surfactants, humectants, and solubilizers, and then water is added and stirred evenly to obtain hair dye agent B. A method for preparing a black hair dye based on plant extracts is completed.

[0011] In a preferred embodiment of the method for preparing a black hair dye based on plant extracts according to the present invention, in step S1, the mass ratio of plant powder, extractant, and precipitant is (0.5~5):(0.1~5):(0.5~2); the mass ratio of precipitate, co-solvent, and adsorbent is 1(0.5~2):(1~3). When plant powder is dissolved in water, the solid-liquid ratio is (0.5~5):20.

[0012] The method for preparing a black hair dye based on plant extracts according to the present invention, in a preferred embodiment, includes the following steps in step S1: S11. Mix the various plants in the plant raw material in equal mass ratio and grind them to obtain plant powder. Add 0.5 to 5 parts by mass of the plant powder to 20 parts by mass of water, then add 0.1 to 5 parts by mass of extractant, 0.1 to 2 parts by mass of stabilizer, and add pH adjuster A to adjust the pH to 9 to 11. Stir and mix evenly, then place in a sealed container and heat to boiling. After boiling, continue to simmer for 16 to 36 hours. Plant ingredient A consists of any one or more of the following: ginkgo leaves, arborvitae, rhubarb, cockscomb flower, chrysanthemum, mulberry, black tea, green tea, gentian, lichen, and catechu; The stabilizer is any one of the following: ascorbic acid and ascorbate, vitamin E, glutamic acid and glutamate, nicotinic acid and nicotinate; pH adjuster A is any one of the following: sodium hydroxide, potassium hydroxide, ammonia, triethylamine ammonium chloride, ethanolamine, sodium bicarbonate, sodium carbonate, ammonium citrate, and sodium sulfide; S12. After filtering and separating the insoluble residue, rinse the residue at least three times, discard the filter residue, collect all the filtrate and combine it with the stewing solution, cool to room temperature, and obtain the first solution. S13. Add 0.5 to 2 parts by weight of precipitant to the first solution, stir well, let stand at room temperature for 10 to 20 hours, filter to separate the precipitate and obtain the precipitate. S14. Add water and 0.5 to 2 parts by weight of co-solvent to the precipitate, and stir until the filter residue is completely dissolved to obtain the second solution; S15. Add 1 to 3 parts by mass of adsorbent to the second solution, let it stand for 10 to 20 hours, and then filter to obtain the third solution. The adsorbent can be any one of the following: magnesium hydroxide, magnesium oxide, and activated carbon; S16. The third solution is concentrated under reduced pressure and dried to obtain the plant extract.

[0013] In a preferred embodiment of the method for preparing a black hair dye based on plant extracts according to the present invention, in step S2, the plant extract is added to water in a mass ratio of 1 to 10 parts and pH adjuster B in a mass ratio of 0.1 to 1 part. After heating and stirring to dissolve, a surfactant is added and stirring is continued. Then, any one or more of a humectant, reducing agent, solubilizer, chelating agent, and preservative are added.

[0014] In a preferred embodiment of the method for preparing a black hair dye based on plant extracts according to the present invention, in steps S2 and S3, the surfactant is one or more of cetearyl alcohol, fatty alcohol polyether ~20, ethoxylated C16~18-alcohol, oleyl alcohol, and hexadecyltrimethylammonium chloride; the reducing agent is mercaptoacetic acid; the pH adjuster B is ethanolamine; the solubilizer is PEG-40 hydrogenated castor oil; and the preservative is polylysine.

[0015] The present invention discloses a method for preparing a black hair dye based on plant extracts. In a preferred embodiment, in step S2, the hair dye A component comprises the following mass percentages: plant extracts: 1%~3.75%, cetearyl alcohol: 2.5%~5%, ethoxylated C16~18-ol: 1%~3%; hexadecyltrimethylammonium chloride: 0.5%~1%, oleyl alcohol: 0.5%~1%, propylene glycol: 1%~3%; PEG-40 hydrogenated castor oil: 0.5%~1%, thioglycolic acid: 1%~1.5%, polylysine: 0.1%~0.2%, disodium EDTA: 0.05%~1%, sodium sulfite: 0.1%~0.4%, ethanolamine: 0.1%~3%, and water: 76.15%~91.75%. In step S3, the mass percentage of hair dye agent B is as follows: ferrous sulfate: 1%~3.75%, cetearyl alcohol: 3%~5%, ethoxylated C16~18-ol: 1%~3%, hexadecyltrimethylammonium chloride: 0.5%~1%, oleyl alcohol: 0.5%~1%, propylene glycol: 1%~3%, PEG~40 hydrogenated castor oil: 0.5%~1%, and water: 82.25%~92.5%.

[0016] The present invention discloses a method for preparing a black hair dye based on plant extracts. As a preferred method, the method of using the black hair dye is as follows: after washing and drying the hair, apply hair dye A evenly to the hair. After 10 to 30 minutes, apply an equal amount of hair dye B evenly to the hair. After 5 to 10 minutes, wash and dry the hair with shampoo. The hair dyeing is then complete.

[0017] This invention selects one or more of the following as raw materials for the extract: rice root and ginkgo leaf, arborvitae, rice root, rhubarb, cockscomb flower, chrysanthemum, mulberry, black tea, green tea, cockscomb flower, gentian, lichen, and catechu.

[0018] Rice roots (also known as rice rootlets, glutinous rice roots, or dried roots and rhizomes of rice) are rich in unsaturated phenolic acids. Other plant extracts mainly contain flavonoids, isoflavones, diflavonoids, and anthocyanins, where R1, R2 = H, OH (glycosides); and R3, R4, R5, R6 = H, OH. In natural plant extracts, these substances are usually in a mixed state, and for hair dyeing purposes, further purification is unnecessary; they can be used directly in the next reaction.

[0019]

[0020] The aforementioned natural flavonoids, isoflavones, diflavonoids, and anthocyanins require the following reaction (condensation of amines and ketones):

[0021] The amino group in this compound is weakly basic, making it prone to protonation and forming intramolecular and intermolecular hydrogen bonds and electrostatic interactions. This reduces its water solubility and makes it more likely to aggregate in water.

[0022] Meanwhile, the iron in ferrous sulfate readily forms complexes with phenolic hydroxyl groups, causing multiple molecules with phenolic hydroxyl groups to chain together to form oligomers and produce extremely strong visible light absorption (darkening).

[0023] These complex oligomers, possessing both hydrogen bonds and electrostatic forces, can form numerous hydrogen bonds and electrostatic interactions with keratin (hair), generating extremely strong adsorption. Simultaneously, the thiol groups within them can exchange with disulfide bonds in keratin to form covalent bonds, ensuring colorfastness and wash resistance.

[0024] After the hair dye is applied to the hair surface, it gradually increases its contact with air, causing the phenols in it to be gradually oxidized by oxygen. This process is catalyzed by iron, because iron has a mixed oxidation state of +2 and +3, which can help transfer electrons and accelerate the oxidation process.

[0025] As oxidation proceeds, the number of hydroxyl groups gradually decreases, the molecular weight increases, the range of intermolecular conjugation increases, the color becomes darker, and the water solubility is lower, thus achieving effective binding and color fixation of the hair dye on the hair surface.

[0026]

[0027] Furthermore, the unsaturated phenolic acids in this product undergo addition reactions with amines (ethanolamine, cysteine) to form dopamine analogs, which can oxidize and cyclize in air to form indole derivatives, i.e., melanin-like substances. This process can react and condense simultaneously with the various flavonoid polyphenols mentioned above, effectively improving hair color and colorfastness. Simultaneously, the substituents in this melanin contain thiol groups derived from cysteine, which can form disulfide bonds with hair, thereby improving wash resistance.

[0028] Cetearyl alcohol, fatty alcohol polyethers (~20), and ethoxylated C16~18-ols, among others, act as surfactants. These surfactants reduce the surface tension of hair dye systems, allowing dyes and other components to disperse better in the solution, thus improving the dyeing effect. Surfactants help the hair dye contact the hair more evenly, promoting the dyeing reaction and resulting in a more uniform color. Simultaneously, surfactants also have emulsifying properties, enabling the oily and watery components in the hair dye to mix evenly, forming a stable emulsion system.

[0029] Thioglycolic acid is the main reducing agent. It can break the disulfide bonds that maintain the structure of hair, causing the hair fiber to soften and swell, making it easier for subsequent dye molecules to enter the hair shaft. At the same time, it can also prevent the dye from oxidizing and becoming ineffective prematurely.

[0030] Ethanolamine, as a pH adjuster B, helps open the hair cuticles, enhances the reduction efficiency of thioglycolic acid, and provides a stable alkaline environment for dye molecules, ensuring a uniform hair dyeing effect.

[0031] Cetyltrimethylammonium chloride (cationic surfactant): It has softening, emulsifying, antistatic and bactericidal properties. When added to the oil phase, it helps the oil phase to disperse in the aqueous phase. At the same time, it acts as a hair conditioner to make hair smoother after dyeing.

[0032] Sodium oleate (oleyl alcohol): As an anionic surfactant, it is a compound composed of hydrophobic and hydrophilic groups. It has excellent emulsifying, penetrating and detergency properties. In hair dyes, it plays a role in thickening, emulsifying and improving the texture of the paste.

[0033] PEG-40 hydrogenated castor oil: acts as an emulsifier and solubilizer, allowing oil-soluble components to dissolve in water and stabilizing the system.

[0034] Polylysine: used as a preservative and antibacterial agent.

[0035] Sodium sulfite: a reducing agent and antioxidant, it prevents plant extracts from oxidizing and changing color, and stabilizes the effective ingredients in hair dye.

[0036] Ferrous sulfate plays a crucial role as a mordant in hair dyeing. After plant extracts interact with hair to color it, ferrous sulfate binds to the dye within the hair fibers, forming a more stable complex. This complex fixes the dye within the hair fibers, thereby improving colorfastness and making the dyed color last longer and less prone to fading. Ferrous sulfate may also have a certain color-adjusting effect on hair, making black appear deeper and more natural.

[0037] In addition to the ingredients mentioned above, other ingredients are added to hair dyes. For example, moisturizers such as propylene glycol can retain hair moisture during the dyeing process, preventing hair from becoming dry and brittle. Chelating agents such as ethylenediaminetetraacetic acid can capture metal ions such as calcium and magnesium in water, preventing these ions from reacting with other ingredients and causing the product to change color or deteriorate, while also reducing the damage of metal ions to the hair.

[0038] The present invention has the following advantages: (1) High safety. The black hair dye of the present invention uses plant extracts as the core ingredients and does not contain harmful chemicals such as common paraphenylenediamine and ammonia. Plant extracts cause minimal damage to hair and scalp, effectively reducing the damage to hair protein structure caused by chemicals in traditional hair dyes, preventing hair from becoming dry, brittle, and prone to breakage, maintaining hair moisture and nutrients, and keeping hair healthy after dyeing.

[0039] (2) Excellent hair dyeing effect. This hair dye can color hair evenly, thanks to the action of surfactants. Surfactants reduce the surface tension of the hair dye system, allowing plant extracts and other ingredients to be more evenly dispersed in the solution and to better contact the hair. During the dyeing process, it ensures that each hair can fully absorb the dyeing ingredients, thereby achieving a uniform dyeing effect and avoiding uneven coloring.

[0040] (3) The natural and long-lasting color after dyeing is closely related to the synergistic effect of plant extracts and ferrous sulfate mordant. Plant extracts participate in the chemical reaction during the dyeing process, and the resulting pigments can naturally adhere to the hair fibers, presenting a natural black color. Ferrous sulfate, as a mordant, forms a stable complex with the dye in the hair fibers, greatly enhancing color fastness. Even after multiple washes, the hair color remains vibrant and long-lasting, and is not easily faded. Compared with traditional hair dyes, the hair dye of this invention performs better in maintaining color stability, allowing consumers to maintain their ideal hair color for a long time. Attached Figure Description

[0041] Figure 1 This is a flowchart of a method for preparing a black hair dye based on plant extracts; Figure 2 Example 1 shows the dyeing effect of a plant extract-based black hair dye on 9-degree bleached hair. Figure 3 Example 2 shows the dyeing effect of a black hair dye based on plant extracts and its preparation method on hair bleached to level 9. Figure 4 A schematic diagram of the dyeing effect on 9-degree bleached hair, comparing a black hair dye based on plant extracts and its preparation method to Example 1. Figure 5 Example 3 shows the dyeing effect of a plant extract-based black hair dye on 9-degree bleached hair. Figure 6 Example 4 shows the dyeing effect of a black hair dye based on plant extracts and its preparation method on hair bleached to level 9. Figure 7This is a schematic diagram of the dyeing effect on 9-degree bleached hair, as shown in Comparative Example 2, of a black hair dye based on plant extracts and its preparation method. Figure 8 Example 5 shows the dyeing effect of a plant extract-based black hair dye on 9-degree bleached hair. Figure 9 Example 6 illustrates the dyeing effect of a plant extract-based black hair dye on 9-degree bleached hair. Figure 10 This is a schematic diagram of the dyeing effect on 9-degree bleached hair, as shown in Comparative Example 3, of a black hair dye based on plant extracts and its preparation method. Figure 11 Example 7 illustrates the dyeing effect of a plant extract-based black hair dye on 9-degree bleached hair. Figure 12 Example 8 shows the dyeing effect of a black hair dye based on plant extracts and its preparation method on 9-degree bleached hair. Figure 13 Example 4 shows the dyeing effect of a plant extract-based black hair dye and its preparation method on hair bleached to level 9. Detailed Implementation

[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example 1

[0043] like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method include the following steps: S11. Select multiple plants from the following: ginkgo leaves, arborvitae, rice roots, rhubarb, cockscomb, chrysanthemum, mulberry, black tea, green tea, gentian, lichen, and catechu. Mix the plant raw materials in equal mass ratios and perform pulverization and grinding. Add 1 part by mass of the obtained plant powder to 30 parts by mass of water (solid-liquid ratio 1:30), then add 1 part by mass of extractant, 0.1 part by mass of stabilizer, and pH adjuster A to adjust the pH to 9-11. Stir thoroughly to ensure uniform mixing of all components. Place the mixed material in a sealed container and heat to boiling. After boiling, maintain low power and continue simmering for approximately 24 hours. Those skilled in the art should understand that the purpose of simmering is to promote the full dissolution of the effective components in the plant powder; therefore, the simmering power and duration can be reasonably adjusted according to actual conditions.

[0044] Plant-based raw materials also include a preliminary preparation process: washing the purchased plant materials to remove surface impurities, dirt, and dust. Washing with running water is recommended to ensure the cleanliness of the plant materials. Then, further processing is carried out according to the characteristics of different plants and the selected extraction method.

[0045] S12. Filter the above mixture to separate insoluble residues, and wash the residues at least three times. Collect all the filtrates and combine them. Discard the filter residues and cool the resulting solution to ambient temperature to obtain the first solution.

[0046] S13. Add 1 part by mass of precipitant (based on the mass of plant extract) to the first solution, stir quickly to mix evenly, and then let stand at room temperature for 12 hours. After the precipitate in the first solution has completely formed, separate the precipitate by filtration to obtain filter residue (precipitate).

[0047] S14. Add water and 1 part of co-solvent (based on the mass fraction of the precipitate) to the filter residue obtained by filtration, and stir until the filter residue is completely dissolved to obtain the second solution.

[0048] S15. Add 2 parts by mass (based on the mass of the precipitate) of adsorbent to the second solution to adsorb the impurities therein. After standing for 12 hours, filter the solution and take the filtrate, which is the third solution.

[0049] S16. The third solution is concentrated under reduced pressure (by reducing the pressure of the sealed container through vacuum, the third solution is evaporated at a temperature below the boiling point of normal pressure), and then dried to finally obtain the plant extract.

[0050] Wherein: pH adjuster A is, for example, sodium hydroxide, ammonia, ammonium chloride, potassium dihydrogen phosphate, or ammonium bicarbonate; preferably, the concentration of ammonia is 20-30%.

[0051] Extractants may be one or more of the following: formaldehyde, acetaldehyde, propionaldehyde, sodium formaldehyde sulfoxylate, benzaldehyde, acetone, cyclohexanone.

[0052] The co-solvents may be one or more of the following: tartaric acid (and its salts), citric acid, disodium EDTA.

[0053] The precipitant may be one or more of the following: phenol, p-methylphenol, urea, ammonia.

[0054] The adsorbent may be one or more of the following: magnesium hydroxide, magnesium oxide, activated carbon.

[0055] Stewing allows the active ingredients in the plants to dissolve into the water, and the rinsing liquid used to wash away residue is also added to the stewing solution.

[0056] The extractant utilizes the principle of similarity and miscibility with the target substance to dissolve and separate the active ingredient from the mixture.

[0057] The precipitant interacts with the target substance through intermolecular hydrogen bonding and co-crystallization, promoting the formation of an insoluble substance and thus achieving separation.

[0058] The cosolvent forms a complex or double salt with the target substance, which has higher solubility, thereby improving its solubility in the solvent.

[0059] S2. Add the weighed plant extract to an appropriate amount of water, heat and stir until fully dissolved. Add the surfactant and continue stirring to ensure the surfactant and plant extract powder are thoroughly mixed to form a uniform dispersion. Next, add the humectant, reducing agent, and pH adjuster B in sequence. Water can be added to the required mass percentage. Continue heating and stirring to ensure all components are fully mixed. After natural cooling, this is hair dye agent A.

[0060] This also includes reagent testing. For other ingredients such as surfactants, ferrous sulfate, humectants, reducing agents, and pH adjusters, quality testing is required to ensure they meet the corresponding quality standards. Surfactants need to be checked for purity and active ingredient content; ferrous sulfate needs to be checked for iron content and impurity content; humectants, reducing agents, and pH adjusters need to be checked for active ingredient content and stability. After passing the tests, each ingredient is accurately weighed according to the formula proportions.

[0061] The specific method is as follows: plant extracts are mixed with emulsifiers, surfactants, reducing agents, pH adjuster B, moisturizers, and chelating agents in a certain proportion, stirred evenly, and hair dye agent A is prepared. The specific mass percentage and composition range of hair dye agent A are as follows: plant extract powder (1%~3.75%), cetearyl alcohol (2.5%~5%), ethoxylated C16~18-ol (1%~3%), hexadecyltrimethylammonium chloride (0.5%~1%), oleyl alcohol (0.5%~1%), propylene glycol (1%~3%), PEG-40 hydrogenated castor oil (0.5%~1%), thioglycolic acid (1%~1.5%), polylysine (0.1%~0.2%), disodium ethylenediaminetetraacetate (0.05%~1%), sodium sulfite (0.1%~0.4%), ethanolamine (0.1%~3%), and the remainder is water.

[0062] S3. Weigh ferrous sulfate, surfactant, etc. according to the proportion, add an appropriate amount of water, heat and stir evenly to fully dissolve in water, continue heating and stirring for 30 minutes to ensure that all components are fully mixed, and after natural cooling, it is agent B. The specific mass percentage and composition of hair dye agent B are as follows: ferrous sulfate (1%~3.75%), cetearyl alcohol (3%~5%), ethoxylated C16~18-ol (1%~3%), hexadecyltrimethylammonium chloride (0.5%~1%), oleyl alcohol (0.5%~1%), propylene glycol (1%~3%), PEG~40 hydrogenated castor oil (0.5%~1%), and the remainder is water.

[0063] Steps S2 and S3 also include reagent testing: For other ingredients such as surfactants, ferrous sulfate, humectants, reducing agents, and pH adjusters, quality testing is required to ensure they meet the corresponding quality standards. Surfactants should be checked for purity and active ingredient content; ferrous sulfate should be checked for iron content and impurity content; humectants, reducing agents, and pH adjusters should be checked for active ingredient content and stability. After passing the tests, each ingredient should be accurately weighed according to the formula proportions.

[0064] S4. Before dyeing your hair, wash it thoroughly with a mild shampoo, avoiding those containing excessive chemicals to prevent affecting the dyeing results. After washing, gently towel dry your hair, keeping it slightly damp. Apply the prepared hair dye (A) evenly to your hair. You can use a hair dye brush to ensure even coverage of each strand. The application time for A is 15 minutes.

[0065] After the hair dyeing process is complete, prepare a mordant solution with a concentration of 1% to 5% using ferrous sulfate and apply it evenly to the hair, ensuring full contact with the mordant. Mordant treatment should last for 5 minutes. During the mordant process, gently massage the hair to help the mordant better bind with the dye in the hair. After mordant treatment, rinse the hair thoroughly with clean water to remove any remaining mordant. Finally, wash the hair with shampoo and rinse thoroughly with clean water.

[0066] Complete the "dye first, then mordant" hair dyeing process.

[0067] Weigh out ferrous sulfate, surfactant, etc. according to the specified proportions, add an appropriate amount of water, heat and stir until fully dissolved in the water, continue heating and stirring for 30 minutes, and then let it cool naturally to obtain agent B.

[0068] In this embodiment, step S11 uses ginkgo leaves, arborvitae, rice roots, rhubarb and cockscomb flowers as plant raw materials, formaldehyde as the extractant, ascorbic acid as the stabilizer, sodium hydroxide as the pH adjuster A, and the pH value is adjusted to 10; in step S13, phenol is the precipitant; in step S14, tartaric acid (and its salt) is the co-solvent; and in step S15, magnesium hydroxide is the adsorbent.

[0069] In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract powder (1%) + cetearyl alcohol (3%) + ethoxylated C16~18-ol (3%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%) + mercaptoacetic acid (1.5%) + disodium EDTA (0.1%) + sodium sulfite (0.4%) + ethanolamine (3%), with the remainder being water.

[0070] In step S3, the specific mass percentage and composition of hair dye agent B are as follows: ferrous sulfate (3.75%) + cetearyl alcohol (3.5%) + ethoxylated C16~18-ol (1.6%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%), with the remainder being water.

[0071] The dyeing effect of this embodiment on hair bleached to level 9 is as follows: Figure 2 As shown, after dyeing, the color fully develops in 25-30 minutes, resulting in an even, light brown hair color (due to a slightly lower content of plant extract powder, less large-molecule melanin is formed). After 50 washes, the hair color shows no fading, demonstrating good colorfastness.

[0072] Example 2 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are identical to those in Example 1. The same plant extract is used in Example 1, except that the components in steps S2-S4 differ from those in Example 1. The specific components are as follows: In step S2, the specific mass percentage and composition of hair dye A are as follows: plant extract A (2.14%) + cetearyl alcohol (5%) + ethoxylated C16-18-ol (3%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG-40 hydrogenated castor oil (1%) + mercaptoacetic acid (1.5%) + disodium EDTA (0.1%) + sodium sulfite (0.4%) + ethanolamine (3%), with the remainder being water.

[0073] In step S3, the specific mass percentage and composition of hair dye agent B are as follows: Raw material formula of agent B: ferrous sulfate (1%) + cetearyl alcohol (3.5%) + ethoxylated C16-18-ol (1.6%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG-40 hydrogenated castor oil (1%), with the remainder being water.

[0074] The dyeing effect of this embodiment on hair bleached to level 9 is as follows: Figure 3As shown, the color fully develops within 25-30 minutes after dyeing, resulting in an even, jet-black hair color. After 50 washes, the hair color shows no fading, demonstrating good colorfastness.

[0075] Compare with Example 1 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are identical to those in Example 1. The only difference between the plant extracts and Example 1 is the raw materials used; the plant raw materials are only ginkgo leaves, arborvitae, rhubarb, and cockscomb flowers. The components and preparation methods of steps S2 to S4 are exactly the same as in Example 2. In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract powder (2.14%) + cetearyl alcohol (5%) + ethoxylated C16~18-ol (3%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%) + mercaptoacetic acid (1.5%) + disodium EDTA (0.1%) + sodium sulfite (0.4%) + ethanolamine (3%), with the remainder being water.

[0076] In step S3, the specific mass percentage and composition of hair dye agent B are as follows: Raw material formula of agent B: ferrous sulfate (1%) + cetearyl alcohol (3.5%) + ethoxylated C16~18-ol (1.6%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%), with the remainder being water.

[0077] This comparative example shows the dyeing effect on hair bleached to level 9. Figure 4 As shown, the left side shows hair before dyeing, the middle side shows hair after dyeing, and the right side shows hair after 50 washes. It can be seen that the color uniformity after dyeing is generally poor, appearing as a dark gray (meaning that the plant extracts did not use rice root; they relied solely on the self-oxidation and polymerization of flavonoids, isoflavones, diflavonoids, anthocyanins, etc., mainly forming oligomeric brown products, making it difficult to form large black molecules). After 50 washes, the hair showed fading, indicating poor colorfastness.

[0078] Example 3 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are identical to those in Example 1, except that: in step S11, the raw materials for the plant extracts are chrysanthemum, mulberry, rice root, and black tea in equal mass ratios; the extractant is acetaldehyde; the stabilizer (glutamate nicotinic acid) is 1.5 parts by mass; and the pH adjuster A is ammonium bicarbonate, adjusting the pH to 9; in step S13, the precipitant is p-methylphenol, and the mixture is allowed to stand for 10 hours; in step S14, the co-solvent is citric acid; and in step S15, the adsorbent is activated carbon, and the mixture is allowed to stand for 10 hours. The components in steps S2 to S4 are different from those in Example 1, and the specific components are as follows: In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract powder (1%) + cetearyl alcohol (2.5%) + ethoxylated C16~18-ol (1%) + hexadecyltrimethylammonium chloride (0.5%) + oleyl alcohol (0.8%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%) + mercaptoacetic acid (1.5%) + sodium sulfite (0.4%) + ethanolamine (3%), with the remainder being water.

[0079] In step S3, the specific mass percentage and composition of hair dye agent B are as follows: Raw material formula of agent B: ferrous sulfate (2.25%) + cetearyl alcohol (5%) + ethoxylated C16~18-ol (3%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%), with the remainder being water.

[0080] The dyeing effect of this embodiment on hair bleached to level 9 is as follows: Figure 5 As shown, the color fully develops within 30-40 minutes after dyeing, resulting in an even brown color (due to the relatively small amount of plant extract powder used). After 50 washes, the hair color shows no significant fading, indicating good colorfastness.

[0081] Example 4 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are exactly the same as those in Example 3, using the same plant extracts as in Example 3. The components in steps S2 to S4 are different from those in Example 3, and the specific components are as follows: In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract powder (1.5%) + cetearyl alcohol (2.5%) + ethoxylated C16~18-ol (2%) + hexadecyltrimethylammonium chloride (0.5%) + oleyl alcohol (1%) + propylene glycol (2%) + PEG~40 hydrogenated castor oil (1%) + mercaptoacetic acid (1.5%) + sodium sulfite (0.1%) + ethanolamine (2%), with the remainder being water.

[0082] In step S3, the specific mass percentage and composition of hair dye agent B are as follows: Raw material formula of agent B: ferrous sulfate (2.25%) + cetearyl alcohol (5%) + ethoxylated C16~18-ol (3%) + hexadecyltrimethylammonium chloride (0.5%) + oleyl alcohol (0.5%) + propylene glycol (1%) + PEG~40 hydrogenated castor oil (1%), with the remainder being water.

[0083] The dyeing effect of this embodiment on hair bleached to level 9 is as follows: Figure 6As shown, the color develops within 30-40 minutes after dyeing, resulting in an even and rich natural black. After 50 washes, the hair color showed no fading, demonstrating good colorfastness.

[0084] Compare with Example 2 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are identical to those in Example 3. The only difference between the plant extracts and Example 3 is the raw materials used; the plant raw materials are chrysanthemum, mulberry, and black tea. The preparation methods for steps S2 to S4 are exactly the same as in Example 3. In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract (2.14%) + cetearyl alcohol (5%) + ethoxylated C16~18-ol (3%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%) + mercaptoacetic acid (1.5%) + disodium EDTA (0.1%) + sodium sulfite (0.4%) + ethanolamine (3%), with the remainder being water.

[0085] In step S3, the specific mass percentage and composition of hair dye agent B are as follows: ferrous sulfate (1%) + cetearyl alcohol (3.5%) + ethoxylated C16~18-ol (1.6%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%), with the remainder being water.

[0086] This comparative example shows the dyeing effect on hair bleached to level 9. Figure 7 As shown, the color fully develops in 25-30 minutes after dyeing, with average color uniformity and a grayish hue. After 50 washes, the hair shows signs of fading, indicating poor colorfastness.

[0087] Example 5 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are identical to those in Example 1, except that: in step S11, the raw materials for the plant extracts are green tea, gentian, and rice root in equal mass ratios; the extractant is propionaldehyde; the stabilizer (vitamin E) is 1 part by mass; the pH adjuster A is ammonia water with a concentration of 20-30%; the pH is adjusted to 9.5; and after boiling, the mixture is continuously simmered at low power for about 24 hours; in step S13, the precipitant is urea; and the mixture is allowed to stand for 11 hours; in step S14, the co-solvent is polyphosphoric acid; and in step S15, the adsorbent is aluminum hydroxide; and the mixture is allowed to stand for 11 hours. The components in steps S2 to S4 are different from those in Example 1, and the specific components are as follows: In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract (2.14%) + cetearyl alcohol (5%) + ethoxylated C16~18-ol (3%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%) + mercaptoacetic acid (1.5%) + polylysine (0.2%) + disodium EDTA (0.1%) + sodium sulfite (0.4%) + ethanolamine (3%), with the remainder being water.

[0088] In step S3, the specific mass percentage and composition of hair dye agent B are as follows: ferrous sulfate (3.75%) + cetearyl alcohol (3.5%) + ethoxylated C16~18-ol (1.6%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%), with the remainder being water.

[0089] The dyeing effect of this embodiment on hair bleached to level 9 is as follows: Figure 8 As shown, the color fully develops within 20-25 minutes after dyeing, resulting in an even, natural black color. After 50 washes, the hair color shows no fading, demonstrating good colorfastness.

[0090] Example 6 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are exactly the same as those in Example 5, using the same plant extracts as in Example 5. The components in steps S2 to S4 are different from those in Example 5, and the specific components are as follows: In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract (2%) + cetearyl alcohol (5%) + ethoxylated C16~18-ol (3%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (0.5%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (0.5%) + mercaptoacetic acid (1%) + polylysine (0.1%) + disodium ethylenediaminetetraacetate (0.5%) + sodium sulfite (0.2%) + ethanolamine (0.5%), with the remainder being water.

[0091] In step S3, the specific mass percentage and composition of hair dye agent B are as follows: ferrous sulfate (3.75%) + cetearyl alcohol (3.5%) + ethoxylated C16~18-ol (1.6%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (0.5%), with the remainder being water.

[0092] The dyeing effect of this embodiment on hair bleached to level 9 is as follows: Figure 9As shown, the color fully develops within 20-25 minutes after dyeing, resulting in an even color and a soft, translucent natural black. The rightmost image shows the hair after 50 washes; the color shows no fading, indicating good colorfastness.

[0093] Compare with Example 3 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are identical to those in Example 5. The only difference between the plant extracts and Example 5 is the raw materials used; the plant raw materials are only green tea, gentian, and rice root. The components and preparation methods of steps S2 to S4 are exactly the same as in Example 5. In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract (2.14%) + cetearyl alcohol (5%) + ethoxylated C16~18-ol (3%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%) + mercaptoacetic acid (1.5%) + polylysine (0.2%) + disodium EDTA (0.1%) + sodium sulfite (0.4%) + ethanolamine (3%), with the remainder being water.

[0094] Agent B's raw material formula: ferrous sulfate (3.75%) + cetearyl alcohol (3.5%) + ethoxylated C16~18-ol (1.6%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (1%), with the remainder being water.

[0095] This comparative example shows the dyeing effect on hair bleached to level 9. Figure 10 As shown, Figure 10 From left to right: the original 9-degree bleached hair, the hair of this control example after dyeing, and the hair after dyeing and washing 50 times. After dyeing, the color fully developed in 25-30 minutes, with average color uniformity, appearing as a brownish-gray. After 50 washes, the hair showed fading, indicating poor color fastness.

[0096] Example 7 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are identical to those in Example 1, except that: in step S11, the raw materials for the plant extracts are rice roots, lichens, and catechu in equal mass ratios; the extractant is propionaldehyde; the stabilizer (nicotinic acid salt) is 2 parts by mass; the pH adjuster A is sodium hydroxide; the pH is adjusted to 11; and after boiling, the mixture is continuously simmered at low power for about 24 hours; in step S13, the precipitant is p-methylphenol; and the mixture is allowed to stand for 12 hours; in step S14, the co-solvent is disodium EDTA; and in step S15, the adsorbent is activated carbon; and the mixture is allowed to stand for 12 hours. The components in steps S2 to S4 are different from those in Example 1, and the specific components are as follows: In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract (1.5%) + cetearyl alcohol (2.5%) + ethoxylated C16~18-ol (1%) + hexadecyltrimethylammonium chloride (0.5%) + oleyl alcohol (1%) + propylene glycol (1%) + PEG~40 hydrogenated castor oil (1%) + mercaptoacetic acid (1%) + sodium sulfite (0.4%) + ethanolamine (0.1%), with the remainder being water.

[0097] In step S3, the specific mass percentage and composition of hair dye agent B are as follows: ferrous sulfate (2.25%) + cetearyl alcohol (5%) + ethoxylated C16~18-ol (1%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (1%) + PEG~40 hydrogenated castor oil (1%), with the remainder being water.

[0098] The dyeing effect of this embodiment on hair bleached to level 9 is as follows: Figure 11 As shown, the color fully develops within 25-30 minutes after dyeing, resulting in an even, natural black color. After 50 washes, the hair color shows no fading, demonstrating good colorfastness.

[0099] Example 8 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are identical to those in Example 7, using the same plant extracts as in Example 7. The components in steps S2 to S4 are different from those in Example 7, and the specific components are as follows: In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract (3.75%) + cetearyl alcohol (5%) + ethoxylated C16~18-ol (1%) + hexadecyltrimethylammonium chloride (0.5%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (0.5%) + mercaptoacetic acid (1.5%) + sodium sulfite (0.4%) + ethanolamine (3%), with the remainder being water.

[0100] In step S3, the specific mass percentage and composition of hair dye agent B are as follows: ferrous sulfate (2.25%) + cetearyl alcohol (3%) + ethoxylated C16~18-ol (3%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (1%) + PEG~40 hydrogenated castor oil (1%), with the remainder being water.

[0101] The dyeing effect of this embodiment on hair bleached to level 9 is as follows: Figure 12 As shown, the color fully develops within 25-30 minutes after dyeing, resulting in an even, natural black color. After 50 washes, the hair color shows no fading, demonstrating good colorfastness.

[0102] Compare with Example 4 like Figure 1 As shown, a black hair dye based on plant extracts and its preparation method are identical to those in Example 8. The only difference between the plant extracts and Example 8 is the raw materials; the plant raw materials are simply lichen and catechu in equal mass ratios. The components and preparation methods of steps S2 to S4 are exactly the same as in Example 8. In step S2, the specific mass percentage and composition of hair dye agent A are as follows: plant extract (3.75%) + cetearyl alcohol (5%) + ethoxylated C16~18-ol (1%) + hexadecyltrimethylammonium chloride (0.5%) + oleyl alcohol (1%) + propylene glycol (3%) + PEG~40 hydrogenated castor oil (0.5%) + mercaptoacetic acid (1.5%) + sodium sulfite (0.4%) + ethanolamine (3%), with the remainder being water.

[0103] Agent B's raw material formula: ferrous sulfate (2.25%) + cetearyl alcohol (3%) + ethoxylated C16~18-ol (3%) + hexadecyltrimethylammonium chloride (1%) + oleyl alcohol (1%) + propylene glycol (1%) + PEG~40 hydrogenated castor oil (1%), with the remainder being water.

[0104] The dyeing effect of this embodiment on hair bleached to level 9 is as follows: Figure 13 As shown, the color fully develops in 25-30 minutes after dyeing, appearing as a brownish-green. After 50 washes, the hair color fades slightly, indicating moderate colorfastness.

[0105] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A black hair dye based on plant extracts, characterized in that: It consists of hair dye A and hair dye B. Hair dye A contains plant extracts. The plant extracts are obtained by adjusting the pH of rice roots and plant raw material A, stewing, dissolving, precipitating and separating, complexing and re-dissolving the precipitate, removing impurities, filtering, concentrating and drying. The plant material A is any one or more of the following: ginkgo leaves, arborvitae, rhubarb, cockscomb flower, chrysanthemum, mulberry, black tea, green tea, gentian, lichen and catechu; The hair dye B includes ferrous sulfate, emulsifier, and surfactant.

2. The black hair dye based on plant extracts according to claim 1, characterized in that: The plant extract is obtained by reacting unsaturated phenolic acids from rice roots with flavonoids in plant raw material A, followed by reaction with amines and subsequent oxidative polymerization. It is then complexed with ferrous sulfate to obtain oligomers. These oligomers undergo exchange reactions with disulfide bonds in hair keratin to form covalent bonds. The flavonoids include flavonoids, isoflavones, diflavonoids, and anthocyanins. The oligomers are indole derivatives and are macromolecular melanin. The plant extract is in a solid state; The hair dye agent A also includes emulsifiers, surfactants, thioglycolic acid, and water; The black hair dye does not contain phenylenediamine, benzene compounds, or heavy metals.

3. The black hair dye based on plant extracts according to claim 1, characterized in that: The hair dye A component comprises the following by weight percentage: plant extract: 1%~3.75%, cetearyl alcohol: 2.5%~5%, ethoxylated C16~18-ol: 1%~3%; hexadecyltrimethylammonium chloride: 0.5%~1%, oleyl alcohol: 0.5%~1%, propylene glycol: 1%~3%; PEG-40 hydrogenated castor oil: 0.5%~1%, thioglycolic acid: 1%~1.5%, polylysine: 0.1%~0.2%, disodium EDTA: 0.05%~1%, sodium sulfite: 0.1%~0.4%, ethanolamine: 0.1%~3%, and water: 76.15%~91.75%. The hair dye agent B has the following mass percentage composition: ferrous sulfate: 1%~3.75%, cetearyl alcohol: 3%~5%, ethoxylated C16~18-ol: 1%~3%, hexadecyltrimethylammonium chloride: 0.5%~1%, oleyl alcohol: 0.5%~1%, propylene glycol: 1%~3%, PEG~40 hydrogenated castor oil: 0.5%~1%, and water: 82.25%~92.5%.

4. A method for preparing a black hair dye based on plant extracts, characterized in that: Includes the following steps: S1. Mix the plant raw materials and grind them to obtain plant powder. Dissolve the plant powder in water and adjust the pH value to 9-11. Add the extractant, boil and keep warm, filter to obtain the first solution. Use a precipitant to precipitate the first solution, and then use a cosolvent to complex and dissolve the precipitate. After the adsorbent adsorbs the impurities in the solution, filter, concentrate and dry to obtain the plant extract. The plant material consists of rice roots and plant material A, wherein plant material A is a substance containing flavonoids and / or isoflavones and / or diflavonoids and / or anthocyanins. The extractant is any one of the following: formaldehyde, acetaldehyde, propionaldehyde, sodium formaldehyde sulfoxylate, benzaldehyde, acetone, and cyclohexanone; The precipitant is any one of the following: phenol, p-methylphenol, urea, and ammonia; The co-solvent is any one of the following: tartaric acid, tartrate, citric acid, and disodium EDTA; S2. Add the plant extract to water, heat and stir to dissolve, then add surfactant and continue stirring. Then add any one or more of moisturizer, reducing agent, solubilizer, pH adjuster B, chelating agent, and preservative. Add water again and continue heating and stirring. After mixing completely, let it cool naturally to obtain hair dye agent A. S3. Ferrous sulfate is mixed with any one or more of emulsifiers, surfactants, humectants, and solubilizers, and then water is added and stirred evenly to obtain hair dye agent B. A method for preparing a black hair dye based on plant extracts is completed.

5. The method for preparing a black hair dye based on plant extracts according to claim 4, characterized in that: In step S1, the mass ratio of the plant powder, the extractant, and the precipitant is (0.5~5):(0.1~5):(0.5~2). The mass ratio of the precipitate, the co-solvent, and the adsorbent is 1 (0.5~2): (1~3). The solid-liquid ratio of the plant powder when dissolved in water is (0.5~5):

20.

6. The method for preparing a black hair dye based on plant extracts according to claim 4, characterized in that: Step S1 includes the following steps: S11. Mix the various plants in the plant raw material in equal mass ratio and grind them to obtain the plant powder. Add 0.5 to 5 parts by mass of the plant powder to 20 parts by mass of water, then add 0.1 to 5 parts by mass of the extractant, 0.1 to 2 parts by mass of the stabilizer, and add pH adjuster A to adjust the pH to 9 to 11. After stirring and mixing evenly, place it in a sealed container and heat it to boiling. After boiling, continue to simmer for 16 to 36 hours. The plant material A is any one or more of the following: ginkgo leaves, arborvitae, rhubarb, cockscomb flower, chrysanthemum, mulberry, black tea, green tea, gentian, lichen and catechu; The stabilizer is any one of the following: ascorbic acid and ascorbate, vitamin E, glutamic acid and glutamate, nicotinic acid and nicotinate; The pH adjuster A is any one of the following: sodium hydroxide, potassium hydroxide, ammonia, triethylamine ammonium chloride, ethanolamine, sodium bicarbonate, sodium carbonate, ammonium citrate, and sodium sulfide; S12. After filtering and separating the insoluble residue, the residue is rinsed at least three times, the filter residue is discarded, all the filtrate is collected and combined with the stewing solution, and cooled to room temperature to obtain the first solution. S13. Add 0.5 to 2 parts by weight of the precipitant to the first solution, stir well, let stand at room temperature for 10 to 20 hours, and filter to separate the precipitate. S14. Add water and 0.5 to 2 parts by weight of the co-solvent to the precipitate, and stir until the filter residue is completely dissolved to obtain the second solution; S15. Add 1 to 3 parts by weight of adsorbent to the second solution, let it stand for 10 to 20 hours, and then filter to obtain the third solution. The adsorbent is any one of the following: magnesium hydroxide, magnesium oxide, and activated carbon; S16. The third solution is concentrated under reduced pressure and dried to obtain the plant extract.

7. The method for preparing a black hair dye based on plant extracts according to claim 4, characterized in that: In step S2, the plant extract is added to water in a mass ratio of 1 to 10 parts and pH adjuster B in a mass ratio of 0.1 to 1 part. After heating and stirring to dissolve, the surfactant is added and stirring is continued. Then, any one or more of the humectant, the reducing agent, the solubilizer, the chelating agent, and the preservative are added.

8. The method for preparing a black hair dye based on plant extracts according to claim 4, characterized in that: In steps S2 and S3, the surfactant is one or more of cetearyl alcohol, fatty alcohol polyether ~20, ethoxylated C16~18-alcohol, oleyl alcohol, and hexadecyltrimethylammonium chloride; the reducing agent is mercaptoacetic acid; the pH adjuster B is ethanolamine; the solubilizer is PEG-40 hydrogenated castor oil; and the preservative is polylysine.

9. The method for preparing a black hair dye based on plant extracts according to claim 4, characterized in that: In step S2, the mass percentage of hair dye agent A is as follows: plant extract: 1%~3.75%, cetearyl alcohol: 2.5%~5%, ethoxylated C16~18-ol: 1%~3%; hexadecyltrimethylammonium chloride: 0.5%~1%, oleyl alcohol: 0.5%~1%, propylene glycol: 1%~3%; PEG~40 hydrogenated castor oil: 0.5%~1%, thioglycolic acid: 1%~1.5%, polylysine: 0.1%~0.2%, disodium EDTA: 0.05%~1%, sodium sulfite: 0.1%~0.4%, ethanolamine: 0.1%~3%, water: 76.15%~91.75%; In step S3, the hair dye agent B has the following mass percentages: ferrous sulfate: 1%~3.75%, cetearyl alcohol: 3%~5%, ethoxylated C16~18-ol: 1%~3%, hexadecyltrimethylammonium chloride: 0.5%~1%, oleyl alcohol: 0.5%~1%, propylene glycol: 1%~3%, PEG~40 hydrogenated castor oil: 0.5%~1%, and water: 82.25%~92.5%.

10. The method for preparing a black hair dye based on plant extracts according to claim 4, characterized in that: The method of using the black hair dye is as follows: After washing and drying the hair, apply the hair dye A evenly to the hair. After 10-30 minutes, apply the same amount of hair dye B evenly to the hair. After 5-10 minutes, wash and dry the hair with shampoo. The hair dyeing is now complete.

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