Multi-color plant hair dyeing cream and preparation method thereof

Abstract

The invention provides a multi-color plant hair dyeing cream and a preparation method thereof. The hair dyeing cream contains a water phase, an oil phase and an active phase, and is prepared by taking sodium alginate as a thickening agent / film-forming agent, sorbitol as a humectant / stabilizer, juglone as a color fixing agent, indigo blue, carmine, curcumin and sodium chlorophyllin as plant pigments, cationic guar gum, ferrous sulfate and tannic acid as a color fixing enhancer and absolute ethyl alcohol and deionized water as solvents. After a water phase, an oil phase and an active phase are respectively prepared, the water phase, the oil phase and the active phase are fully mixed, and the composite material is prepared. The multi-color plant hair dyeing cream prepared by the invention does not contain phenylenediamine and other components, and shows better multi-color dyeing effect and color stability.

Description

Technical Field

[0001] This invention relates to the field of the cosmetics industry, and more specifically, to a multi-color plant-based hair dye and its preparation method. Background Technology

[0002] Hair dyeing is becoming increasingly popular as a cosmetic procedure. It effectively conceals gray hair caused by factors such as genetics, disease, nutrition, or aging, making one appear younger and has become an important way for contemporary young people to express their fashion sense (color dyeing). However, most commercially available chemical hair dyes currently use phenylenediamine as their main ingredient, and phenylenediamine is classified as a Group 3 carcinogen by the International Agency for Research on Cancer. With increasing awareness of health and environmental protection, research into the application of plant-based hair dyes is becoming more in-depth, and hair dye oils derived from natural plants are becoming a more ideal choice.

[0003] Plant-based hair dyes use plant pigments as their main active ingredient. These pigments are environmentally friendly and biodegradable, offering a significant advantage in terms of environmental protection compared to the pollution problems caused by chemical hair dyes. Furthermore, plant-based ingredients typically do not cause primary irritation or hair damage, resulting in a lower risk of sensitization. It's worth noting that many of the plant ingredients used also possess medicinal value, thus the resulting hair dyes often offer comprehensive benefits beyond just coloring, including hair nourishment, conditioning, and scalp care. In addition, the unique natural colors of plant-based hair dyes are difficult to replicate with chemical products. With environmental awareness increasingly prevalent, plant-based hair dyes will undoubtedly become the mainstream development direction of the future hair dyeing market.

[0004] Walnuts, belonging to the Juglandaceae family, are among the world's four major nuts. Their thick, green outer husk is called the husk or green rind. my country has the world's largest walnut planting area, with an annual green husk production exceeding 3.5 million tons. Walnut husks are rich in polyphenols, naphthoquinones (such as juglone), and flavonoids. Juglone is the main active coloring ingredient; its structure is similar to intermediates in some synthetic hair dyes, and it has the ability to bind to hair keratin. Current patented hair dyeing technologies based on juglone generally use a combination of its powder or extract with other raw materials. However, this method has significant limitations: low pigment utilization, requiring multiple applications, and offering too limited a color range, failing to meet the diverse needs of consumers, especially fashion-conscious young and middle-aged individuals. Therefore, developing a safe, multi-colored plant-based hair dye free of toxic / allergenic phenylenediamine-like ingredients is crucial. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a multi-color plant-based hair dye and its preparation method, which is a multi-color hair dye and dyeing method for various hair types.

[0006] This invention provides a multi-color plant-based hair dye and its preparation method. The hair dye contains an aqueous phase, an oil phase, and an active phase. The components of each phase are as follows: the aqueous phase consists of a thickener / film-forming agent, a moisturizer / stabilizer, and the remainder is deionized water; the oil phase consists of a color-fixing agent, a color-fixing enhancer, plant pigments, and the remainder is deionized water and anhydrous ethanol; the active phase consists of a color-fixing enhancer and the remainder is deionized water.

[0007] The thickener / film-forming agent in the aqueous phase is sodium alginate, which forms a film in the acidic environment of the scalp, protecting the scalp during the dyeing process. The moisturizer / stabilizer is sorbitol, which helps make the hair feel light and smooth after dyeing, maintaining a natural and moderate level of moisture on the hair surface without burdening the scalp. The color-fixing agent in the oil phase is juglone; the color-fixing enhancer is cationic guar gum, which uses its positive charge to adsorb onto the negatively charged hair cuticle, repairing the hair cuticle, enhancing color fastness, and reducing fading; the plant pigment is one of indigo, carmine, curcumin, or sodium chlorophyll. The color-fixing enhancers in the active phase are ferrous sulfate and tannic acid.

[0008] The structural formula of juglone is shown in Formula I: Formula I.

[0009] Preferably, the color-fixing agent juglone is obtained by extraction, separation, and purification of walnut green husk.

[0010] Preferably, the green walnut skin is freeze-dried under vacuum for 36 hours, pulverized and passed through an 80-mesh sieve, and then extracted, separated and purified by solvent-dependent and heat-dependent auxiliary factors such as microwave extraction to obtain juglone.

[0011] In some specific embodiments of the present invention, the microwave extraction and purification process is as follows: Take 2g of green tangerine peel powder, add 30mL of 90% ethanol, and sonicate at 30℃ (200W) for 40min. Then, seal the solution and place it in a microwave oven, heating on low for 25s. Concentrate the extract under reduced pressure at 65℃ until no alcohol odor remains, recover the ethanol, add one volume of deionized water to the concentrate, and mix well. Extract twice with an equal volume of ethyl acetate, and combine the ethyl acetate phases. Evaporate the ethyl acetate phase to dryness, and adsorb the obtained concentrate with an appropriate amount of silica gel, drying it into a powder. Load the sample dry and separate using silica gel column chromatography. Elute with petroleum ether (boiling range 30-60℃) and ethyl acetate, collect the eluents in fractions, combine the eluents containing juglone, and concentrate under reduced pressure to dryness to obtain the final product.

[0012] Preferably, the ratio of the aqueous thickener / film-forming agent, humectant / stabilizer, aqueous deionized water, oil-phase fixing agent, oil-phase fixing enhancer, plant pigment, anhydrous ethanol, oil-phase deionized water, active phase fixing enhancer, and active phase deionized water is (1.5%–3%):(2–5%):(5–15) ml:(0.1%–1%):(0.1–0.5%):(0–1%):(3–8) ml:(1–4) ml:(0.5–1.5%):(1–5) ml.

[0013] A further preferred ratio is 2.5%:4%:10ml:0.5%:0.2%:1%:5ml:2ml:0.9%:2ml.

[0014] In a preferred embodiment of the present invention, an aqueous phase, an oil phase, and an active phase are first prepared. Then, the oil phase is slowly added to the aqueous phase and mixed thoroughly. After the mixture is cooled to room temperature, the active phase is added. Once all phases are mixed thoroughly, the preparation of the hair dye is complete.

[0015] Preferably, in the oil phase preparation process, 5 mL of anhydrous ethanol is first taken, and juglone and plant pigments (indigo, curcumin, carmine, sodium chlorophyll) are added; then cationic guar gum is dissolved in 2 mL of distilled water; the cationic guar gum solution is added to the juglone and plant pigment solution, and ultrasonic dissolution is assisted.

[0016] Preferably, the mass ratio of the color-fixing enhancer ferrous sulfate to tannic acid is 1:0.8.

[0017] This invention provides a method for preparing a multi-color plant-based hair dye, comprising the following steps: S1) Thickener / film-forming agent and humectant / stabilizer are heated and dissolved in deionized water to prepare an aqueous phase, wherein the thickener / film-forming agent is sodium alginate and the humectant / stabilizer is sorbitol; S2) The color-fixing agent and plant pigment are dissolved in anhydrous ethanol and added to an aqueous solution of color-fixing enhancer to prepare an oil phase. The color-fixing agent is juglone, the plant pigment is one of indigo, curcumin, carmine, and sodium chlorophyll, and the color-fixing enhancer is cationic guar gum. S3) The color-fixing enhancer is ultrasonically dissolved in deionized water to prepare the active phase, wherein the color-fixing enhancer is tannic acid and ferrous sulfate; S4) Slowly add the oil phase to the water phase and mix thoroughly. Then add the active phase and mix thoroughly to complete the preparation of the multi-color hair dye. S5) Take the hair to be dyed, wash it with warm water, shake off the water, and then soak it in the hair dye. Make sure the hair dye is evenly applied to the hair surface and let it stand at 40℃ for 30-60 minutes to dye. S6) Take out the dyed hair and rinse and dry it repeatedly more than 8 times.

[0018] In step S1), the preferred heating and melting temperature is 60°C.

[0019] In step S2), the color-fixing agent juglone is obtained by extracting, separating and purifying walnut green skin through microwave extraction and other solvent-dependent and heat-dependent auxiliary factors.

[0020] In step S3), the mass ratio of tannic acid to ferrous sulfate is 1:0.8.

[0021] Preferably, in this invention, the oil phase is slowly added to the aqueous phase while increasing the speed of magnetic stirring. After complete and uniform mixing, the mixture is cooled to room temperature. The active phase is then slowly added while maintaining high-speed magnetic stirring. Once completely and uniformly mixed, the preparation of the hair dye is complete.

[0022] Experimental results show that the multi-color plant-based hair dye prepared in this invention can evenly dye hair of various colors. The components have good affinity with the human body, and the dyeing effect can be maintained for 2 to 3 months. Sodium alginate forms a film in the acidic environment of the scalp, protecting the scalp during the dyeing process. Sorbitol helps to make dyed hair feel light and smooth, maintaining a natural and moderate level of moisture on the hair surface without burdening the scalp. Cationic guar gum, with its positive charge, adsorbs onto the negatively charged hair cuticle, repairing the hair cuticle, enhancing color fastness, and reducing fading. Ferrous sulfate and tannic acid, in the form of a complex, enhance the adsorption of plant pigments, strengthen the interaction between juglone and hair keratin, and improve dyeing performance and color fastness.

[0023] Compared with existing technologies, this invention provides a multi-color plant-based hair dye, formulated with juglone, a natural plant extract from walnut husk, combined with natural plant pigments such as indigo, carmine, curcumin, and sodium chlorophyll. It is completely free of toxic or irritating ingredients such as phenylenediamine, resorcinol, and ammonium hydroxide. The synergistic chemical-physical action of multiple color-fixing agents, plant pigments, and color-enhancing agents dyes hair into a series of colors, resulting in a natural and even color without altering hair quality. The product is safe, reliable, and non-irritating. Attached Figure Description

[0024] Figure 1 Image showing the effect of hair dye coloring; Figure 1 a represents the hair dyeing effect of a 0.25% juglone solution. Figure 1 b represents the hair dyeing effect of a hair dye containing 0.5% juglone. Figure 2 Before and after photos of the effects of multi-color hair dyes; Figure 2 a is a control for white hair; Figure 2b represents the hair dyeing effect of the juglone group hair dye; Figure 2 c represents the hair dyeing effect of the juglone + curcumin combination hair dye; Figure 2 d represents the hair dyeing effect of the juglone + indigo hair dye. Figure 2 e represents the hair dyeing effect of the juglone + carmine hair dye; Figure 2 f represents the hair dyeing effect of the hair dye without juglone and plant pigments; Figure 2 g represents the hair dyeing effect of the juglone + sodium chlorophyll group hair dye; Figure 3 A bar chart showing the stability of hair dyeing effects. Detailed Implementation

[0025] To further illustrate the present invention, the following describes in detail the multi-color plant-based hair dye and its preparation method provided by the present invention with reference to embodiments.

[0026] Example 1: Preparation of Multi-Color Plant-Based Hair Dye (1) Extraction, separation and purification of natural plant color-fixing agents Walnut green husks were freeze-dried under vacuum for 36 hours, pulverized, and passed through an 80-mesh sieve. 2g of the green husk powder was added to 30mL of 90% ethanol and sonicated at 30℃ (200W) for 40min. The solution was then sealed and placed in a microwave oven and heated on low for 25s. The extract was concentrated under reduced pressure at 65℃ until no alcohol odor remained, the ethanol was recovered, and an equal volume of water was added to the concentrate and mixed well. The extract was then extracted twice with an equal volume of ethyl acetate, and the ethyl acetate phases were combined. The ethyl acetate phase was evaporated to dryness, and the resulting concentrate was adsorbed onto a suitable amount of silica gel and dried into a powder. The powder was then loaded onto a silica gel column for separation. Elution was performed with petroleum ether (boiling range 30–60℃) and ethyl acetate, and the eluents were collected fractionally. The eluents containing juglone were combined and concentrated to dryness under reduced pressure to obtain the final product.

[0027] (2) Preparation of aqueous phase, oil phase and active phase Aqueous phase: Place 10 mL of deionized water in a water bath and add 0.25 g of sodium alginate and 0.4 g of sorbitol under magnetic stirring at 60 °C.

[0028] Oil phase: Take 0.05g of juglone and 0.1g of plant pigment (one of indigo, curcumin, carmine, or sodium chlorophyll) and place them in 5mL of anhydrous ethanol. Take 0.02g of cationic guar gum, dissolve it in 2mL of deionized water, and pour it into the solution containing juglone and pigment. Sonicate to dissolve for 30min.

[0029] Active phase: Add 0.05g tannic acid and 0.04g ferrous sulfate to 2mL of deionized water and sonicate for 30min.

[0030] (3) Preparation and dyeing process of multi-color plant-based hair dye The oil phase is slowly added to the aqueous phase under magnetic stirring. During the process, the magnetic stirring speed is increased. After mixing evenly, the mixture is cooled to room temperature, and the active phase is added drop by drop while maintaining high-speed magnetic stirring. After mixing evenly, the preparation of the hair dye is complete.

[0031] Take a section of hair to be dyed and wash it three times with warm water. Shake off the excess water, then apply the prepared hair dye evenly to the hair and heat it at 40℃ for 40 minutes. Afterward, rinse the hair dye with clean water and rinse and dry it repeatedly eight times.

[0032] Example 2: Effect of sodium alginate, juglone, and plant pigment dosage The hair dye was prepared using the same steps as in Example 1, with sodium alginate dosages of 1.5%, 2%, 2.5%, and 3%, respectively.

[0033] The prepared hair dye was evaluated using the following viscosity grading criteria: Grade A: After standing for 5 minutes, it is completely fluid, unformed, and flows rapidly like water when poured, without resistance, and cannot adhere to the hair; Grade B: After standing for 5 minutes, it slightly swells, flows slowly at the edges, and forms a thin thread when poured, with slight stringing when stirred; Grade C: After standing for 5 minutes, it is stably piled up, with a smooth, non-flowing surface, and forms a continuous ribbon when poured, with obvious elastic stringing when stirred; Grade D: After standing for 5 minutes, it solidifies and bulges, with no fluidity on the surface, requiring force to flow out, the strings break easily, and it is difficult to apply evenly; Grade E: After standing for 5 minutes, it becomes solid, does not deform, cannot be poured naturally, and needs to be scraped for use. The experimental results are shown in Table 1.

[0034] Table 1. Effect of different doses of sodium alginate on the viscosity of hair dye. Sodium alginate dosage static state Flow patterns Viscosity grade Operational Evaluation 1.5% Completely flat Water droplets A Unable to attach hair 2% Slight buildup fine thread B Difficult to adhere evenly 2.5% Stable stacking Continuous strip C Easy to apply without dripping 3% solid bulge illiquid D The comb is hard to push open The results showed that the hair dye prepared with 2.5% sodium alginate had a moderate viscosity, reaching grade C, making it easy to apply and preventing dripping. Therefore, 2.5% is the optimal dosage of sodium alginate.

[0035] The hair dye was prepared and dyeing experiments were conducted following the same steps as in Example 1, with juglone dosages of 0.25%, 0.5%, 0.75%, and 1%. In the 0.75% and 1% groups, the juglone was not completely dissolved, while the dyeing effects in the 0.25% and 0.5% groups were as shown. Figure 1 As shown. Figure 1 Figure a shows the hair dyeing effect of using a 0.25% juglone solution. Figure 1 Figure b shows the hair dyeing effect of a 0.5% juglone solution. The results indicate that the 0.5% group has a significant coloring effect, while the 0.25% group has a lighter effect. Therefore, the optimal juglone solution dosage is 0.5%.

[0036] The hair dye was prepared and dyeing experiments were conducted following the same steps as in Example 1, with plant pigment amounts of 0.5% and 1%, respectively. The experimental results showed that when the plant pigment amount was 0.5%, the hair color after dyeing was a mixture of juglone orange and the pigment; when the plant pigment amount was 1.0%, the hair color after dyeing was clearly the original pigment color. Therefore, by adjusting the type and amount of juglone and plant pigment, hair dyes with multi-color dyeing effects can be easily obtained.

[0037] Example 3: Preparation of hair dye (juglone) The hair dye consists of an aqueous phase, an oil phase, and an active phase. The aqueous phase is prepared by placing 10 mL of deionized water in a water bath at 60°C with magnetic stirring, then adding 0.25 g of sodium alginate and 0.4 g of sorbitol. The oil phase is prepared by dissolving 0.05 g of juglone in 5 mL of anhydrous ethanol, then adding 0.02 g of cationic guar gum dissolved in 2 mL of deionized water to the juglone solution and sonicating for 30 min. The active phase is prepared by adding 0.05 g of tannic acid and 0.04 g of ferrous sulfate to 2 mL of deionized water and sonicating for 30 min.

[0038] The oil phase is slowly added to the aqueous phase under magnetic stirring. During the process, the magnetic stirring speed is increased. After mixing evenly, the mixture is cooled to room temperature, and the active phase is added drop by drop while maintaining high-speed magnetic stirring. After mixing evenly, the preparation of the hair dye is complete.

[0039] Example 4: Preparation of hair dye (juglone + curcumin) The hair dye consists of an aqueous phase, an oil phase, and an active phase. The aqueous phase is prepared by placing 10 mL of deionized water in a water bath at 60°C with magnetic stirring, then adding 0.25 g of sodium alginate and 0.4 g of sorbitol. The oil phase is prepared by dissolving 0.05 g of juglone and 0.1 g of curcumin in 5 mL of anhydrous ethanol, then adding 0.02 g of cationic guar gum dissolved in 2 mL of deionized water to the solution containing juglone and the dye, and sonicating for 30 min. The active phase is prepared by adding 0.05 g of tannic acid and 0.04 g of ferrous sulfate to 2 mL of deionized water, and sonicating for 30 min.

[0040] The oil phase is slowly added to the aqueous phase under magnetic stirring. During the process, the magnetic stirring speed is increased. After mixing evenly, the mixture is cooled to room temperature, and the active phase is added drop by drop while maintaining high-speed magnetic stirring. After mixing evenly, the preparation of the hair dye is complete.

[0041] Example 5: Preparation of hair dye (juglone + indigo) The hair dye consists of an aqueous phase, an oil phase, and an active phase. The aqueous phase is prepared by placing 10 mL of deionized water in a water bath at 60°C with magnetic stirring, then adding 0.25 g of sodium alginate and 0.4 g of sorbitol. The oil phase is prepared by dissolving 0.05 g of juglone and 0.1 g of indigo in 5 mL of anhydrous ethanol, then adding 0.02 g of cationic guar gum dissolved in 2 mL of deionized water to the solution containing juglone and the dye, and sonicating for 30 min. The active phase is prepared by adding 0.05 g of tannic acid and 0.04 g of ferrous sulfate to 2 mL of deionized water, and sonicating for 30 min.

[0042] The oil phase is slowly added to the aqueous phase under magnetic stirring. During the process, the magnetic stirring speed is increased. After mixing evenly, the mixture is cooled to room temperature, and the active phase is added drop by drop while maintaining high-speed magnetic stirring. After mixing evenly, the preparation of the hair dye is complete.

[0043] Example 6: Preparation of hair dye (juglone + carmine) The hair dye consists of an aqueous phase, an oil phase, and an active phase. The aqueous phase is prepared by placing 10 mL of deionized water in a water bath at 60°C with magnetic stirring, then adding 0.25 g of sodium alginate and 0.4 g of sorbitol. The oil phase is prepared by dissolving 0.05 g of juglone and 0.1 g of carmine in 5 mL of anhydrous ethanol, then adding 0.02 g of cationic guar gum dissolved in 2 mL of deionized water to the solution containing juglone and the pigment, and sonicating for 30 min. The active phase is prepared by adding 0.05 g of tannic acid and 0.04 g of ferrous sulfate to 2 mL of deionized water, and sonicating for 30 min.

[0044] The oil phase is slowly added to the aqueous phase under magnetic stirring. During the process, the magnetic stirring speed is increased. After mixing evenly, the mixture is cooled to room temperature, and the active phase is added drop by drop while maintaining high-speed magnetic stirring. After mixing evenly, the preparation of the hair dye is complete.

[0045] Example 7: Preparation of hair dye (without juglone and plant pigments) The hair dye consists of an aqueous phase, an oil phase, and an active phase. The aqueous phase is prepared by placing 10 mL of deionized water in a water bath at 60°C with magnetic stirring, then adding 0.25 g of sodium alginate and 0.4 g of sorbitol. The oil phase is prepared by dissolving 0.02 g of cationic guar gum in 2 mL of deionized water and then adding the dissolved guar gum to the ethanol solution, followed by ultrasonic dissolution for 30 min. The active phase is prepared by adding 0.05 g of tannic acid and 0.04 g of ferrous sulfate to 2 mL of deionized water, followed by ultrasonic reaction for 30 min.

[0046] The oil phase is slowly added to the aqueous phase under magnetic stirring. During the process, the magnetic stirring speed is increased. After mixing evenly, the mixture is cooled to room temperature, and the active phase is added drop by drop while maintaining high-speed magnetic stirring. After mixing evenly, the preparation of the hair dye is complete.

[0047] Example 8: Preparation of hair dye (juglone + sodium chlorophyll) The hair dye consists of an aqueous phase, an oil phase, and an active phase. The aqueous phase is prepared by placing 10 mL of deionized water in a water bath at 60°C with magnetic stirring, then adding 0.25 g of sodium alginate and 0.4 g of sorbitol. The oil phase is prepared by dissolving 0.05 g of juglone and 0.1 g of sodium chlorophyll in 5 mL of anhydrous ethanol, then adding 0.02 g of cationic guar gum dissolved in 2 mL of deionized water to the solution containing juglone and the dye, and sonicating for 30 min. The active phase is prepared by adding 0.05 g of tannic acid and 0.04 g of ferrous sulfate to 2 mL of deionized water, and sonicating for 30 min.

[0048] The oil phase is slowly added to the aqueous phase under magnetic stirring. During the process, the magnetic stirring speed is increased. After mixing evenly, the mixture is cooled to room temperature, and the active phase is added drop by drop while maintaining high-speed magnetic stirring. After mixing evenly, the preparation of the hair dye is complete.

[0049] Example 9: Evaluation of the dyeing effect of multi-color hair dye.

[0050] Six groups of hair dyes prepared in Examples 3-8 were used in hair dyeing experiments. The color-fixing agents and plant pigments used were juglone, juglone + curcumin, juglone + indigo, juglone + carmine, no juglone or plant pigments, and juglone + sodium chlorophyll, respectively. Gray hair was washed three times with warm water, spun dry, and the prepared hair dye was evenly applied to the hair. The hair was then heated at 40°C for 40 minutes. The hair dye was then rinsed off with water, and the hair was rinsed and dried repeatedly eight times. Each experiment was repeated three times. The dyeing results were as follows: Figure 2 As shown, Figure 2 Image a shows a control sample with white hair. Figure 2 Figure b in the middle represents the juglone group. Figure 2 Figure c in the middle represents the juglone + curcumin group. Figure 2 Figure d in the middle represents the juglone + indigo group. Figure 2 Figure e in the middle represents the juglone + carmine group. Figure 2 Figure f in the middle represents the group without juglone and plant pigments. Figure 2 Figure g in the middle represents the group consisting of juglone and sodium chlorophyll. Figure 2 The dyeing effects shown in the images are all the result of drying after dyeing and rinsing eight times.

[0051] The results showed that juglone, combined with the color-fixing enhancers ferrous sulfate and tannic acid, could effectively and evenly dye hair black; the combination of juglone and curcumin could dye hair bright yellow; the combination of juglone and indigo could dye hair blue-black; the combination of juglone and carmine could dye hair orange-red; without juglone and plant pigments, the combination of ferrous sulfate and tannic acid could dye hair light black; and the combination of juglone and sodium chlorophyll could dye hair brown. This demonstrates that the color-fixing effect met expectations, and the prepared multi-color plant-based hair dye can be used to dye hair black, bright yellow, blue-black, orange-red, light black, or brown.

[0052] Example 10: Evaluation of the stability of the dyeing effect of multi-color hair dye. The hair dye was prepared following the same steps as in Example 1. After dyeing, the hair samples were washed with 100 mL of a 5% (w / v) shampoo solution with a pH of 6 at room temperature (5°C) with continuous stirring for 4 minutes. The washed hair samples were then rinsed in 300 mL of deionized water for 3 minutes and finally air-dried. Color fastness testing was performed on all samples obtained after the shampooing treatment.

[0053] The color parameters of hair before and after washing were measured using a colorimeter. Measured parameter: L * a * b * The hair sample is laid flat on the instrument, and the hair samples from different areas are measured repeatedly. The color difference ΔE value is calculated according to the following formula to evaluate the color change before and after washing.

[0054] △E=[(△L * ) 2 +(△a * ) 2 +(△b * ) 2 ] 1 / 2 In the formula, △L * , △a * , △b * L represents before and after hair dyeing. * a * b * The difference. The result is as follows. Figure 3 As shown.

[0055] The results showed that no significant change in hair color occurred when the number of washes did not exceed 20, and all ΔE values ​​were less than 3, indicating that the color change caused by this washing was imperceptible to the human eye. This demonstrates that the prepared hair dye has good color-fixing properties and exhibits good stability when used for hair dyeing.

[0056] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A multi-color plant-based hair dye and its preparation method, comprising an aqueous phase, an oil phase and an active phase, using sodium alginate as a thickener / film-forming agent, sorbitol as a moisturizer / stabilizer, juglone as a color-fixing agent, plant pigments including indigo, carmine, curcumin and sodium chlorophyll, and cationic guar gum, ferrous sulfate and tannic acid as color-fixing enhancers, and anhydrous ethanol and deionized water as solvents; Juglone is obtained by extraction, separation and purification of walnut green husk using microwave extraction and other solvent-dependent and heat-energy-dependent auxiliary factors. The ratio of the aqueous phase thickener / film-forming agent, moisturizer / stabilizer, aqueous phase deionized water, oil phase fixing agent, oil phase fixing enhancer, plant pigment, anhydrous ethanol, oil phase deionized water, active phase fixing enhancer, and active phase deionized water is (1.5%~3%):(2~5%):(5~15)ml:(0.1%~1%):(0.1~0.5%):(0~1%):(3~8)ml:(1~4)ml:(0.5~1.5%):(1~5)ml; The mass ratio of the color-fixing reinforcing agent ferrous sulfate to tannic acid is 1:0.

8.

2. The multi-color plant-based hair dye according to claim 1 and its preparation method, comprising the following steps: S1) Thickener / film-forming agent and humectant / stabilizer are heated and dissolved in deionized water to prepare an aqueous phase, wherein the thickener / film-forming agent is sodium alginate and the humectant / stabilizer is sorbitol; S2) The color-fixing agent and plant pigment are dissolved in anhydrous ethanol and added to an aqueous solution of color-fixing enhancer to prepare an oil phase. The color-fixing agent is juglone, the plant pigment is one of indigo, curcumin, carmine, and sodium chlorophyll, and the color-fixing enhancer is cationic guar gum. S3) The color-fixing enhancer is ultrasonically dissolved in deionized water to prepare the active phase, wherein the color-fixing enhancer is tannic acid and ferrous sulfate; S4) Slowly add the oil phase to the water phase and mix thoroughly. Then add the active phase and mix thoroughly to complete the preparation of the multi-color hair dye. S5) Take the hair to be dyed, wash it with warm water, shake off the water, and then soak it in the hair dye. Make sure the hair dye is evenly applied to the hair surface and let it stand at 40℃ for 30-60 minutes to dye. S6) Take out the dyed hair and rinse and dry it repeatedly more than 8 times.

3. The application of the multi-color plant-based hair dye according to claim 1 or the multi-color plant-based hair dye prepared by the preparation method according to claim 2 in multi-color dyeing of various hair types.

4. The application according to claim 3, characterized in that, The multi-color plant-based hair dye is used to dye hair of various colors, including black, bright yellow, blue-black, orange-red, light black, and brown.

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