Compositions for covering gray hair and methods for their preparation, shampoos

Abstract

This application relates to the field of daily chemical products, specifically a composition for covering gray hair, its preparation method, and a shampoo. The composition for covering gray hair comprises: 0.05%-1% polydihydroxyindole, 0.05%-1% purulent melanin, 0.02%-0.1% sodium isoascorbate, 12%-18% of surfactant (solid content), 0.1%-0.2% oil-controlling active ingredient, 0.5%-1.5% hair conditioner, and the balance being water. Polydihydroxyindole and purulent melanin replace aniline substances (such as p-phenylenediamine) in traditional hair dyes, avoiding strong allergenicity and potential carcinogenicity. Polydihydroxyindole naturally oxidizes in air to form a black substance that directly adheres to gray hair; purulent melanin is modified to carry a positive charge and has a small particle size, making it easy to penetrate and adsorb onto the hair cuticle, enhancing its coloring power. The synergistic effect of these two components achieves gradual coverage of gray hair under mild conditions (such as in a shampoo environment), rather than a one-time strong dyeing.

Description

Technical Field

[0001] This application relates to the field of daily chemical products, and more specifically, to a composition for covering gray hair, a method for preparing the same, and a shampoo. Background Technology

[0002] Current shampoos generally achieve their claimed core effects by adding active ingredients with cleansing, dandruff-removing, anti-hair loss, and oil-controlling properties. Cleansing agents are surfactants, such as sodium lauryl ether sulfate (SLES), cocamidopropyl betaine (CABP), amino acid surfactants (such as potassium cocoyl glycinate, sodium lauroyl glutamate, etc.), and alkyl glucoside (APG) surfactants; anti-dandruff agents include piroctone ketone ethanolamine salt (OCTO, highly effective and broad-spectrum, but relatively expensive), clomiphene, salicylic acid, sulfur, and natural extracts (tea tree oil, rosemary, etc.); anti-hair loss ingredients mainly include arborvitae leaf extract, saw palmetto fruit extract, biotin, adenosine, and certain peptides (such as myristoyl pentapeptide-17); oil-controlling active ingredients include zinc PCA, capryloyl glycine, plant astringents, and certain absorbent powders (kaolin clay), etc. Existing technologies for covering gray hair typically involve hair dyes containing p-phenylenediamine (PPD), p-aminophenol, and peroxides, which are prone to causing allergies and may be carcinogenic. Currently, there is no shampoo that can combine the effects of traditional shampoo with the ability to gradually cover gray hair. Summary of the Invention

[0003] The purpose of this application is to provide a composition for covering gray hair, a method for preparing the same, and a shampoo.

[0004] In a first aspect, this application provides a composition for covering gray hair, wherein the composition for covering gray hair comprises, by weight percentage: Polydihydroxyindole 0.05%-1%, melanin 0.05%-1%, sodium isoascorbate 0.02%-0.1%, surfactant solid content 12%-18%, oil-controlling active ingredient 0.1%-0.2%, hair conditioner 0.5%-1.5%, balance water.

[0005] In the above technical solution, polydihydroxyindole and purulent melanin replace aniline substances (such as p-phenylenediamine) in traditional hair dyes, avoiding strong allergenicity and potential carcinogenicity. Polydihydroxyindole naturally oxidizes in the air to form black substances that directly adhere to gray hair; purulent melanin is modified to carry a positive charge and has a small particle size, making it easy to penetrate and adsorb onto the hair cuticle, enhancing its coloring power. The two work synergistically to achieve gradual coverage of gray hair under gentle conditions (such as in a shampoo environment), rather than a one-time strong dyeing. Sodium isoascorbate, as an antioxidant, crucially balances the oxidation rate of polydihydroxyindole: too low a content (e.g., below 0.02%) leads to excessively rapid oxidation, unstable coloring, and easy degradation; too high a content (e.g., above 0.1%) inhibits oxidation, affecting the coverage effect. This ingredient ensures the stability of artificial melanin during storage and use without affecting its coloring function. Within the above-mentioned ratio range, polydihydroxyindole and purulent melanin can effectively guarantee the effect and durability of covering gray hair. Furthermore, this surfactant content range ensures the composition has sufficient cleaning power (removing grease and dirt) while maintaining system viscosity and foam stability. Content below 12% will result in insufficient cleaning effect, while content above 18% may cause scalp dryness or formulation imbalance. The surfactant is compatible with artificial melanin and will not interfere with the coloring process. The oil-controlling active ingredient is formulated with natural extracts (such as zucchini seed extract and rosemary extract), which inhibits sebum secretion and addresses the oily scalp problem often associated with gray hair. Content within this range effectively controls oil without irritating the scalp, complementing the coverage function. Hair conditioning agents such as hydrolyzed keratin and natural kelp extract repair hair damage and enhance smoothness. This content ensures conditioning effects without affecting the composition's flowability or coloring properties. As a solvent, water maintains the liquid phase environment of the composition, allowing for uniform dispersion of the artificial melanin and active ingredients, ensuring ease of use and stability.

[0006] In other embodiments of this application, the composition for covering gray hair, by weight percentage, comprises: Polydihydroxyindole 0.1%-0.9%, melanin 0.1%-0.9%, sodium isoascorbate 0.02%-0.1%, surfactant solid content 12%-18%, oil-controlling active ingredient 0.1%-0.2%, hair conditioner 0.5%-1.5%, balance water.

[0007] In other embodiments of this application, the composition for covering gray hair, by weight percentage, comprises: Polydihydroxyindole 0.1%-0.8%, melanin 0.1%-0.8%, sodium isoascorbate 0.02%-0.1%, surfactant solid content 12%-18%, oil-controlling active ingredient 0.1%-0.2%, hair conditioner 0.5%-1.5%, balance water.

[0008] In other embodiments of this application, the ratio of the polydihydroxyindole to the purulent melanin is 0.1%: (0.1%~0.8%).

[0009] In other embodiments of this application, the ratio of the polydihydroxyindole to the purulent melanin is 0.6%: (0.5%~0.6%).

[0010] In other embodiments of this application, the surfactant includes at least one of sodium C14-16 olefin sulfonate, sodium methyl cocoyl taurate, sodium lauroyl amphoteric acetate, or cocoamide.

[0011] In other embodiments of this application, the oil-controlling active ingredients include at least one of the following: zucchini seed extract, rosemary extract, tea tree oil, Melaleuca alternifolia leaf oil, or sunflower seed oil.

[0012] In other embodiments of this application, the hair conditioning agent includes at least one of natural kelp extract or hydrolyzed keratin.

[0013] In other embodiments of this application, the composition for covering gray hair also includes a pH adjuster.

[0014] In other embodiments of this application, the amount of pH adjuster added is 0.1% to 1% by mass percentage.

[0015] Secondly, this application provides a method for preparing a composition for covering gray hair, comprising: Mix 0.05%-1% polydihydroxyindole, 0.05%-1% purulent melanin, 0.02%-0.1% sodium isoascorbate, 12%-18% of surfactant solids, 0.1%-0.2% oil-controlling active ingredient, 0.5%-1.5% hair conditioner, and the remainder water thoroughly.

[0016] Thirdly, this application provides a shampoo comprising the composition for covering gray hair provided in any of the first aspects above; Optionally, the amount of the composition for covering gray hair in the shampoo is 1 wt% to 25 wt%. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1These are the experimental results of the flocculation effect in the examples and comparative examples; Figure 2 These are the results of foam experiments for examples and comparative examples; Figure 3 The images show the results of covering gray hair in both the example and comparative versions. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0020] Therefore, the following detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0021] This application provides a composition for covering gray hair, wherein the composition for covering gray hair comprises, by weight percentage: Polydihydroxyindole 0.05%-1%, melanin 0.05%-1%, sodium isoascorbate 0.02%-0.1%, surfactant solid content 12%-18%, oil-controlling active ingredient 0.1%-0.2%, hair conditioner 0.5%-1.5%, balance water.

[0022] In the above technical solution, polydihydroxyindole and purulent melanin replace aniline substances (such as p-phenylenediamine) in traditional hair dyes, avoiding strong allergenicity and potential carcinogenicity. Polydihydroxyindole naturally oxidizes in the air to form black substances that directly adhere to gray hair; purulent melanin is modified to carry a positive charge and has a small particle size, making it easy to penetrate and adsorb onto the hair cuticle, enhancing its coloring power. The two work synergistically to achieve gradual coverage of gray hair under gentle conditions (such as in a shampoo environment), rather than a one-time strong dyeing. Sodium isoascorbate, as an antioxidant, crucially balances the oxidation rate of polydihydroxyindole: too low a content (e.g., below 0.02%) leads to excessively rapid oxidation, unstable coloring, and easy degradation; too high a content (e.g., above 0.1%) inhibits oxidation, affecting the coverage effect. This ingredient ensures the stability of artificial melanin during storage and use without affecting its coloring function. Within the above-mentioned ratio range, polydihydroxyindole and purulent melanin can effectively guarantee the effect and durability of covering gray hair. Furthermore, this surfactant content range ensures the composition has sufficient cleaning power (removing grease and dirt) while maintaining system viscosity and foam stability. Content below 12% will result in insufficient cleaning effect, while content above 18% may cause scalp dryness or formulation imbalance. The surfactant is compatible with artificial melanin and will not interfere with the coloring process. The oil-controlling active ingredient is formulated with natural extracts (such as zucchini seed extract and rosemary extract), which inhibits sebum secretion and addresses the oily scalp problem often associated with gray hair. Content within this range effectively controls oil without irritating the scalp, complementing the coverage function. Hair conditioning agents such as hydrolyzed keratin and natural kelp extract repair hair damage and enhance smoothness. This content ensures conditioning effects without affecting the composition's flowability or coloring properties. As a solvent, water maintains the liquid phase environment of the composition, allowing for uniform dispersion of the artificial melanin and active ingredients, ensuring ease of use and stability.

[0023] The above-mentioned technical solution provides a composition for covering gray hair that combines cleaning, oil control, and conditioning functions, meeting the market demand for "washing, conditioning, and dyeing all in one" products.

[0024] Further optionally, and exemplaryly, in some embodiments of this application, the composition for covering gray hair, by weight percentage, comprises: Polydihydroxyindole 0.05%, 0.06%, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.55%, 0.56%, 0.58%, 0.6%, 0.65%, 0.68%, 0.7%, 0.75%, 0.78%, 0.8%, 0.82%, 0.85%, 0.88%, 0.90%, 0.92%, 0.95%, 0.98%, 1% or any range between two of the aforementioned values; purulent melanin 0.05 %, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.55%, 0.56%, 0.58%, 0.6%, 0.65%, 0.68%, 0.7%, 0.75%, 0.78%, 0.8%, 0.82%, 0.85%, 0.88%, 0.90%, 0.92%, 0.95%, 0.98%, 1% or any range between two of the aforementioned values; sodium isoascorbate 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, 0.05%, 0.055%, 0.06%, 0.065%, 0.07%, 0.075%, 0.08%, 0.085%, 0.09%, 0.095%, 0.1%, or a range between any two of the aforementioned values; the surfactant solid content is 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%. 18%, oil-controlling active ingredients 0.1%, 0.11%, 0.12%, 0.13%, 0.15%, 0.18%, 0.2% or any two of the aforementioned values; hair conditioner 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5% or any two of the aforementioned values, and the balance being water.

[0025] Further, optionally, in some embodiments of this application, the composition for covering gray hair, by weight percentage, comprises: Polydihydroxyindole 0.1%-0.9%, melanin 0.1%-0.9%, sodium isoascorbate 0.02%-0.1%, surfactant solid content 12%-18%, oil-controlling active ingredient 0.1%-0.2%, hair conditioner 0.5%-1.5%, balance water.

[0026] Further, optionally, in some embodiments of this application, the composition for covering gray hair, by weight percentage, comprises: Polydihydroxyindole 0.1%-0.8%, melanin 0.1%-0.8%, sodium isoascorbate 0.02%-0.1%, surfactant solid content 12%-18%, oil-controlling active ingredient 0.1%-0.2%, hair conditioner 0.5%-1.5%, balance water.

[0027] Further, optionally, and exemplary, in some embodiments of this application, the composition for covering gray hair, by weight percentage, comprises: Polydihydroxyindole 0.5%-1%, melanin 0.5%-1%, sodium isoascorbate 0.02%-0.1%, surfactant solid content 12%-18%, oil-controlling active ingredient 0.1%-0.2%, hair conditioner 0.5%-1.5%, balance water.

[0028] Further optionally, in some embodiments of this application, the ratio of the polydihydroxyindole to the purulent melanin is 0.1%: (0.1%~0.8%).

[0029] For example, in some embodiments of this application, the ratio of the polydihydroxyindole to the purulent melanin is 0.1% (0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, or any two of the aforementioned values).

[0030] Further optionally, in some embodiments of this application, the ratio of the polydihydroxyindole to the purulent melanin is 0.1% : (0.2%~0.7%). Further optionally, in some embodiments of this application, the ratio of the polydihydroxyindole to the purulent melanin is 0.1% : (0.3%~0.5%). Further optionally, in some embodiments of this application, the surfactant includes at least one of sodium C14-16 olefin sulfonate, sodium methyl cocoyl taurate, sodium lauroyl amphoteric acetate, or cocoamide.

[0031] Exemplarily, in some embodiments of this application, the surfactant is any one of sodium C14-16 olefin sulfonate, sodium methyl cocoyl taurate, sodium lauroyl amphoteric acetate, or cocamide. Alternatively, in some embodiments of this application, the surfactant is a mixture of sodium C14-16 olefin sulfonate and sodium methyl cocoyl taurate; or in some embodiments of this application, the surfactant is a mixture of sodium lauroyl amphoteric acetate and cocamide; the raw materials in each of the above mixtures can be mixed in any proportion.

[0032] Furthermore, in some embodiments of this application, the oil-controlling active ingredient includes at least one of the following: zucchini seed extract, rosemary extract, tea tree oil, Melaleuca alternifolia leaf oil, or sunflower seed oil.

[0033] For example, in some embodiments of this application, the oil-controlling active ingredient is any one of zucchini seed extract, rosemary extract, tea tree oil, Melaleuca alternifolia leaf oil, or sunflower seed oil. Alternatively, in some embodiments of this application, the oil-controlling active ingredient is a mixture of zucchini seed extract and rosemary extract; or in some embodiments of this application, the oil-controlling active ingredient is a mixture of tea tree oil and Melaleuca alternifolia leaf oil; or in some embodiments of this application, the oil-controlling active ingredient is a mixture of Melaleuca alternifolia leaf oil and sunflower seed oil. The raw materials in each of the above mixtures can be mixed in any proportion.

[0034] Furthermore, in some embodiments of this application, the hair conditioning agent includes at least one of natural kelp extract or hydrolyzed keratin.

[0035] For example, in some embodiments of this application, the hair conditioner is either natural kelp extract or hydrolyzed keratin. Alternatively, in some embodiments of this application, the hair conditioner is a mixture of natural kelp extract and hydrolyzed keratin; the raw materials in the above mixtures can be mixed in any proportion.

[0036] Furthermore, in some embodiments of this application, the composition for covering gray hair also includes a pH adjuster.

[0037] Furthermore, in some embodiments of this application, the amount of pH adjuster added is 0.1% to 1% by mass percentage.

[0038] For example, in some embodiments of this application, the amount of pH adjuster added, by mass percentage, is 0.1%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25%, 0.28%, 0.3%, 0.32%, 0.35%, 0.38%, 0.4%, 0.42%, 0.45%, 0.48%, 0.5%, 0.52%, 0.55%, 0.58%, 0.6%, 0.62%, 0.65%, 0.68%, 0.7%, 0.72%, 0.75%, 0.78%, 0.8%, 0.82%, 0.85%, 0.88%, 0.9%, 0.92%, 0.95%, 0.98%, 1%, or any range between any two of the aforementioned values.

[0039] The above technical solution uses a specific ratio of polydihydroxyindole, sodium isoascorbate, and purulent melanin to effectively cover gray hair, avoiding the use of strongly alkaline hair dyes containing aniline and peroxides. Polydihydroxyindole is easily oxidized in air to form a black substance; an appropriate amount of sodium isoascorbate balances the oxidation rate and dyeing effect; and the modified purulent melanin, with a positive charge and smaller particle size, enhances color absorption. Another advantage of this technical solution is that by combining the main and auxiliary surfactants, adding natural kelp extract and hydrolyzed keratin, and incorporating appropriate amounts of oil-controlling active ingredients, it can achieve both scalp and hair cleansing while effectively controlling scalp oil and conditioning and smoothing hair, thus creating a gentle shampoo that provides excellent cleansing and oil control while also covering gray hair.

[0040] Further optionally, in some embodiments of this application, polydihydroxyindole was purchased from Sichuan Melanin Polymer Materials Co., Ltd., purulent melanin was developed by Guangdong Marubi Biotechnology Co., Ltd., sodium isoascorbate was purchased from Guangzhou Zhaotian Biotechnology Co., Ltd., sodium C14-16 olefin sulfonate was purchased from Stepan Chemical (Shanghai) Co., Ltd., Eversoft™ ACS was purchased from Nanjing Huashi New Materials Co., Ltd., sodium methyl cocoyl taurate was purchased from Innospec Chemical (Beijing) Co., Ltd., sodium lauroyl amphoteric acid was purchased from Guangzhou Xingye Technology Co., Ltd., cocoamide MEA was purchased from Clariant Chemical Technology (Shanghai) Co., Ltd., rosemary (ROSMARINUS OFFICINALIS) extract was purchased from Sabinsa Corporation, zucchini (CUCURBITA PEPO) seed extract was purchased from Givaudan, Melaleuca alternifolia (MELALEUCAALTERNIFOLIA) leaf oil was purchased from Nanjing Spaco Biotechnology Co., Ltd., and sunflower (HELIANTHUS ANNUUS) seed oil was purchased from ALDIVIA SAS. X6™ Bio-Lamina Extract was purchased from Draco Natural Products Inc., KERESTORE 2.0 SB-LQ-(WD) was purchased from Croda Europe Ltd., euxyl™pe 9010 preservative was purchased from Ashland LLC, citric acid monohydrate was purchased from Weifang Yingxuan Industrial Co., Ltd., sodium chloride was purchased from Fuchen (Tianjin) Chemical Reagent Co., Ltd., and fragrance was purchased from Givaudan.

[0041] Some embodiments of this application provide a method for preparing a composition for covering gray hair, comprising: Mix 0.05%-1% polydihydroxyindole, 0.05%-1% purulent melanin, 0.02%-0.1% sodium isoascorbate, 12%-18% of surfactant solids, 0.1%-0.2% oil-controlling active ingredient, 0.5%-1.5% hair conditioner, and the remainder water thoroughly.

[0042] Exemplarily, in some embodiments of this application, a method for preparing a composition for covering gray hair includes: Step S1, Aqueous Phase Preparation Stage: Step S101: In the main mixing pot, add purified water (temperature controlled at 70-75℃) to about 70%-80% of the formula amount, and start stirring (speed 200-300 rpm).

[0043] Step S102: Slowly add surfactants, including but not limited to sodium C14-16 olefin sulfonate, sodium methyl cocoyl taurate, sodium lauroamphoacetate, and cocamide MEA. Continue stirring until all surfactants are completely dissolved and the system is a homogeneous, transparent, viscous liquid.

[0044] Step S103: Add hair conditioning agents, such as natural kelp extract, hydrolyzed keratin, etc., and stir until completely dispersed and evenly mixed.

[0045] Step S104: Add oil-controlling active ingredients, including but not limited to zucchini seed extract, rosemary extract, Melaleuca alternifolia leaf oil, sunflower seed oil, etc., and stir until they are evenly emulsified in the aqueous phase.

[0046] Step S2, Cooling and Homogenization Stage: Step S201: Turn on the jacket cooling water to cool the aqueous phase material to 40-45℃. This temperature range is beneficial for the subsequent addition of heat-sensitive components and prevents degradation of active substances caused by high temperatures.

[0047] Step S202: Add preservative (such as euxyl™PE 9010) and stir well.

[0048] Step S203: Homogenize at 1500-2500 rpm for 3-5 minutes using a homogenizer to ensure that the system particles are fine and free of oil droplets or clumps, so as to obtain a uniform aqueous matrix.

[0049] Step S3, Pretreatment and addition of coloring components: Step S301: In a separate pre-dispersion container, add approximately 10%-15% of the formulation amount of room temperature purified water.

[0050] Step S302: First, add sodium isoascorbate to water and stir at low speed until completely dissolved.

[0051] Step S303: Under low-speed stirring, slowly and in batches add polydihydroxyindole and purulent melanin, stirring until they are completely dispersed to form a uniform coloring slurry. This step avoids introducing too many air bubbles through high-speed stirring and ensures that the coloring particles are fully wetted and dispersed.

[0052] Step S4, Mixing and Conditioning Stage: Step S401: Slowly add the coloring slurry prepared in step S303 into the aqueous phase matrix of the main preparation pot at 40-45℃, wash the pre-dispersion container with the remaining purified water and add it to the main pot to ensure complete transfer.

[0053] Step S402: Maintain 40-45℃ and stir continuously (300-400 rpm) for 10-15 minutes to ensure that the coloring components are fully and evenly mixed with the entire system.

[0054] Step S403: Add flavoring and stir well.

[0055] Step S404: Adjust the pH of the composition to a weakly acidic range of 5.5-6.5 using a pH adjuster (such as an aqueous solution of citric acid monohydrate), which is close to the scalp environment and is gentle and non-irritating.

[0056] Step S405: Add an emulsifying stabilizer (such as sodium chloride) to adjust to a suitable viscosity and stir until homogeneous.

[0057] Step S5, Degassing and Discharge: Step S501: Allow the composition to stand or degas it under vacuum to eliminate air bubbles introduced during stirring.

[0058] Step S502: Take samples for quality inspection (such as pH value, viscosity, color, heat and cold resistance, etc.).

[0059] Step S503: After passing the inspection, cool the material down to below 30℃ before discharging and filling.

[0060] In the above preparation method, the aqueous phase preparation uses a high temperature of 70℃-75℃, which is beneficial for the dissolution of surfactants and conditioning agents; while the coloring component addition stage is controlled at a low temperature of 40-45℃, effectively protecting the heat sensitivity of polydihydroxyindole and purulent melanin and preventing premature oxidation or deactivation. The easily oxidized coloring component is pre-dispersed with an antioxidant (sodium isoascorbate) in a small amount of water. This step ensures that sodium isoascorbate can uniformly coat the coloring particles, providing immediate protection during preparation and storage. This avoids the dust, clumping, and uneven dispersion problems that may occur when dry powder coloring agents are directly added to the main pot.

[0061] Some embodiments of this application provide a shampoo comprising the composition for covering gray hair provided in any of the foregoing embodiments.

[0062] For example, in some embodiments of this application, the amount of the composition for covering gray hair in the shampoo is 1wt% to 25wt%.

[0063] For example, the amount of the composition for covering gray hair in the shampoo is 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, or any two of the aforementioned values.

[0064] The features and performance of this application will be further described in detail below with reference to embodiments: The following raw materials were used in the examples and comparative examples: Polydihydroxyindole was purchased from Sichuan Melanin Polymer Materials Co., Ltd.; purulent melanin was developed by Guangdong Marubi Biotechnology Co., Ltd.; sodium isoascorbate was purchased from Guangzhou Zhaotian Biotechnology Co., Ltd.; sodium C14-16 olefin sulfonate was purchased from Stepan Chemical (Shanghai) Co., Ltd.; Eversoft™ ACS was purchased from Nanjing Huashi New Materials Co., Ltd.; sodium methyl cocoyl taurate was purchased from Innospec Chemical (Beijing) Co., Ltd.; sodium lauroyl amphoteric acid was purchased from Guangzhou Xingye Technology Co., Ltd.; cocoamide MEA was purchased from Clariant Chemical Technology (Shanghai) Co., Ltd.; rosemary (ROSMARINUS OFFICINALIS) extract was purchased from Sabinsa Corporation; zucchini (CUCURBITA PEPO) seed extract was purchased from Givaudan; Melaleuca alternifolia (MELALEUCAALTERNIFOLIA) leaf oil was purchased from Nanjing Spaco Biotechnology Co., Ltd.; and sunflower (HELIANTHUS ANNUUS) seed oil was purchased from ALDIVIA SAS. Draco X6™ Bio-Lamina Extract was purchased from Draco Natural Products Inc., KERESTORE 2.0 SB-LQ-(WD) was purchased from Croda Europe Ltd., euxyl™pe 9010 preservative was purchased from Ashland LLC, citric acid monohydrate was purchased from Weifang Yingxuan Industrial Co., Ltd., sodium chloride was purchased from Fuchen (Tianjin) Chemical Reagent Co., Ltd., and fragrance was purchased from Givaudan.

[0065] Example 1-Example 2 provides a composition for covering gray hair, the specific composition of which is shown in Table 1.

[0066] Table 1

[0067] Examples 3 and 4 provide a composition, the specific composition of which is shown in Table 2.

[0068] Table 2

[0069] Comparative Example 1 provides a composition, the specific composition of which is shown in Table 3.

[0070] Table 3

[0071] Comparative Example 2 Offers commercially available OFF&Relax Revitalizing & Strengthening Shampoo.

[0072] The performance of the samples provided in the above embodiments and comparative examples was tested.

[0073] 1. Light transmittance experiment Transmittance testing is commonly used to assess the flocculation behavior or dispersion stability of shampoo samples. Lower transmittance indicates higher turbidity, meaning that flocs formed during dilution, which is related to the smoothing properties of the shampoo during rinsing.

[0074] The experimental method is as follows: Experimental principle: Transmittance measurement is based on spectrophotometry: when light passes through a sample, some light is absorbed or scattered, and the ratio of transmitted light intensity to incident light intensity is the transmittance. In shampoo testing, transmittance reflects changes in the turbidity of the sample. Increased transmittance after dilution indicates good sample dispersibility; however, excessively low transmittance may indicate flocculent formation, affecting product stability.

[0075] Experimental instruments and reagents: Instruments: Spectrophotometer (such as UV-Vis spectrophotometer), vortex mixer, analytical balance, pipette, cuvette (usually 1 cm path length), constant temperature water bath.

[0076] Reagents: purified water (as diluent and blank), shampoo samples to be tested (Examples 1-2, Examples 3-4, Comparative Example 1, commercially available Off&Relax Revitalizing and Strengthening Shampoo).

[0077] Experimental steps: Step 1: Instrument Calibration Turn on the spectrophotometer and preheat for 30 minutes.

[0078] Set the measurement wavelength to 650 nm (common in turbidity testing, but the specific wavelength may be adjusted according to laboratory standards).

[0079] Rinse the cuvette with purified water, add purified water as a blank control, and adjust the transmittance to 100%.

[0080] Step 2: Sample dilution series preparation Take the shampoo sample to be tested and perform serial volume dilutions with purified water. The dilution ratios range from 1:1 to 1:100 (as shown in Table 1). The specific preparation methods are as follows: 1:1 dilution: Take 1.0 mL of sample + 1.0 mL of purified water.

[0081] 1:2 dilution: Take 1.0 mL of sample + 2.0 mL of purified water.

[0082] 1:3 dilution: Take 1.0 mL of sample + 3.0 mL of purified water. ... 1:100 dilution: Take 0.1 mL of sample + 10.0 mL of purified water (or scale proportionally).

[0084] After each dilution ratio is prepared, immediately vortex the mixture vigorously for 30 seconds to ensure uniform mixing.

[0085] All dilution operations were performed at a constant temperature of 25°C to eliminate the influence of temperature.

[0086] Step 3: Transmittance Measurement Pour each diluted sample into a cuvette, avoiding air bubbles.

[0087] Place it in a spectrophotometer and measure the transmittance (%).

[0088] Each sample was measured three times, and the average value was taken as the final result (the data in Table 1 should be the average value).

[0089] Measurements were taken in order of low dilution to high dilution to reduce cross-contamination.

[0090] Step 4: Data Recording and Analysis Record the transmittance values ​​at each dilution ratio and generate a summary table in Table 1.

[0091] The trend of transmittance with dilution ratio was analyzed: the higher the transmittance, the more transparent the sample; the lower the transmittance, the more flocculent matter there is, which may correspond to better conditioning performance (as in the embodiments of this technical solution).

[0092] Temperature control: The entire experiment was conducted at a constant temperature (25°C) because temperature may affect flocculation behavior.

[0093] Time factor: Measurement should be taken immediately after dilution to avoid settling or changes in flocculents caused by standing.

[0094] Instrument accuracy: Spectrophotometers need to be calibrated regularly to ensure accurate transmittance readings.

[0095] Dilution consistency: All samples were diluted using the same batch of purified water, and the dilution process was performed by the same person to reduce errors.

[0096] The experimental results are shown in Table 4 and Appendix. Figure 1 As shown.

[0097] Table 4

[0098] The experimental data in Table 4 above show that: The transmittance of the samples in Examples 1-4 was generally low (approximately 21.7%-24.9% at a 1:1 dilution) and increased slowly with increasing dilution ratio, indicating that the samples had moderate flocculation, which is consistent with the smoothing properties of shampoo.

[0099] Commercially available products (Off & Relax): have higher transmittance (e.g., 72.7% at a 1:1 dilution), indicating that the sample is more transparent, has less flocculation, and may have weaker conditioning properties.

[0100] Comparative Example 1: Lacking purulent melanin, the light transmittance was slightly higher, indicating that the white hair covering components affected the flocculation behavior.

[0101] The experimental procedure was designed to simulate the dilution process of shampoo during use (such as rinsing), and the change in light transmittance reflects the product's deposition and conditioning effect on the hair. This experiment demonstrates that the technical solution of this application possesses good conditioning properties while maintaining its cleaning function.

[0102] From the instruction manual Figure 1 It can be seen that: Compared with commercially available competitor Off&Relax Revitalizing and Strengthening Shampoo, the technical solution of this application can achieve the smoothing and conditioning properties of normal shampoo during the rinsing process (1:100).

[0103] 2. Foam Experiment The foaming properties of shampoo (including foaming power and foam stability) are determined using the shaking / stirring method. Experimental principle: The shampoo sample solution was foamed by simulating mechanical actions (such as shaking or stirring) in actual use. The immediate foaming ability and foam stability of the product were evaluated by measuring the foam volume at different time points.

[0104] Experimental instruments and reagents: Instruments: stoppered graduated cylinder (e.g., 100mL or 250mL, with an accuracy of 1mL), constant temperature water bath, stopwatch, electronic balance, pipette.

[0105] Reagents: Shampoo sample to be tested, hard water with a hardness of 150 ppm (or hard water as specified in the standard to simulate actual water quality).

[0106] Experimental steps: Step S1: Sample solution preparation: Dilute the shampoo sample with hard water to a 1% aqueous solution (this is a common test concentration, for example: 1.0g sample + 99.0g hard water).

[0107] Place the diluted sample solution in a 40°C constant temperature water bath for at least 30 minutes to ensure that the test temperature is close to the water temperature when a person washes their hair.

[0108] Step S2: Initial foam generation: Take 50 mL of the above-preserved sample solution and pour it into a clean 250 mL stoppered graduated cylinder.

[0109] Vibrate the graduated cylinder vertically 10 times (or use a mechanical oscillator to oscillate at a fixed frequency and amplitude for a fixed time, such as 30 seconds).

[0110] Immediately place the graduated cylinder on the experimental table and start timing with a stopwatch.

[0111] Step S3: Foam height measurement and recording (corresponding to "Number of measurements") At the instant the timing begins (0 seconds), read and record the total volume of the foam layer (including liquid and foam), but usually record the height of the pure foam (mL). This corresponds to "Number of Measurements 1" in the table.

[0112] Subsequently, the foam height was read and recorded again at fixed time intervals (e.g., minutes 1, 2, 3, 4, and 5). These correspond to "Number of Measurements 2 to 7" in the table.

[0113] The entire observation period is typically 5 minutes to assess the decay of the foam.

[0114] Step S4: Repeat the experiment Each sample was tested at least three times in parallel, and the final result was averaged to ensure the reliability of the data.

[0115] The test results are shown in Table 5 and the instruction manual appendix. Figure 2 .

[0116] Table 5

[0117] From the instruction manual Figure 2 As can be seen from Table 5: The initial foam height (first measurement) of the samples in Examples 1-4 was higher than that of the commercially available competitor Off&Relax.

[0118] The foam height increased rapidly and continuously during the first five measurements (e.g., within the first five minutes), indicating that the formulation of this invention has strong foaming potential and can continuously produce rich foam under mechanical action. At the fifth measurement, the foam height of all sample examples reached its peak (276-284 mL), significantly higher than the peak value of commercially available products (257 mL).

[0119] Foam stability was determined by the degree of foam decay after the peak value. From the 5th to the 7th measurement, the foam height of all samples decreased only slightly. Example 1: decreased from 284 mL to 273 mL (only a 3.9% decrease); Example 2: decreased from 281 mL to 275 mL (only a 2.1% decrease). Off & Relax: decreased from 257 mL to 251 mL (a 2.3% decrease).

[0120] The foam stability of the samples from this invention is comparable to or even better than that of commercially available products. The dense and stable foam provides a more pleasant user experience and better encapsulates and removes dirt from the scalp and hair during the cleaning process.

[0121] Comparative Example 1 (without purulent melanin) had the highest foam height at all measurement points. This indicates that the addition of purulent melanin may have a slight inhibitory effect on foam performance, but this inhibition is minor, as the foam performance of Examples 1-4 is still comprehensively superior to commercially available products.

[0122] This demonstrates that the surfactant system of the present invention (sodium C14-16 olefin sulfonate, sodium methyl cocoyl taurate, etc.) is highly efficient, and even with the addition of ingredients to cover gray hair, it can still provide and maintain foam performance that surpasses that of products on the market.

[0123] The gray hair-covering shampoo described in this application not only does not sacrifice its foaming performance due to the addition of artificial melanin, but also reaches or even exceeds the level of commercially available shampoos in terms of foam richness (foaming power) and persistence (stability). This demonstrates that the technical solution has excellent cleaning and foaming performance.

[0124] 3. Oil control performance test Experimental Principle The Sebumeter® sebum meter works on the principle of photometry. The instrument's special abrasive tape becomes translucent after absorbing sebum from the skin's surface. By measuring changes in the tape's transmittance, the sebum content on the skin's surface can be accurately and objectively calculated, in μg / cm².

[0125] Main instrument: Sebum secretion measuring instrument (such as Sebumeter SM 815 from Courage & Khazaka).

[0126] Auxiliary materials: standard cleaning solvent (such as ether), sterile cotton swabs, timer.

[0127] Test samples: Shampoos from Examples 1 and 2, Examples 3 and 4, and Comparative Example 1.

[0128] Test environment: constant temperature and humidity laboratory (usually temperature 22±2℃, humidity 50±10%), subjects need to adapt to this environment for at least 30 minutes.

[0129] Experimental steps: Step S1: Subject Screening and Grouping We recruited a group of healthy subjects with oily or combination scalps.

[0130] Subjects were randomly divided into several groups, each using a test sample (example or comparative example), and it was ensured that there was no significant difference in initial sebum levels between the groups.

[0131] Step S2: Baseline Measurement (Day 0) Use a cotton swab soaked in cleaning solvent to thoroughly clean the designated test area on the subject's scalp (usually the top of the head) to remove all surface sebum.

[0132] Wait 30 minutes (to allow the sebaceous glands to resume their natural secretion).

[0133] The sebum content of this area was measured using a Sebumeter and recorded as the initial value (T0).

[0134] Step S3: Product Use and Tracking Measurement The subjects were given a designated sample and the usage method was standardized: 5g each time, massage the scalp for 1 minute, and rinse thoroughly.

[0135] Subjects were instructed to use the product at a fixed frequency: 3-5 times per week.

[0136] Follow-up measurements were taken on days 1, 7, 14, and 28. Subjects did not use any shampoo products within 24 hours before the test, allowing their sebum to be secreted naturally.

[0137] After acclimatization in a constant temperature and humidity environment, the sebum content of the same test area was directly measured using a Sebumeter and recorded as Tn (e.g., T1, T7...).

[0138] Step S4: Data Processing The formula for calculating the sebum secretion reduction rate is: Reduction rate (%) = [(T0 - Tn) / T0] × 100% Where T0 is the initial value and Tn is the measurement value after using the product on day n.

[0139] The data from all subjects were statistically averaged, and the final results are shown in Table 6.

[0140] Table 6

[0141] The data in the table above shows that: The samples in this application took effect rapidly; after only one day of use, the sebum secretion reduction rate of all samples reached more than 30%, which indicates that the oil-controlling active ingredients can work quickly, possibly by instantly absorbing oil or shrinking hair follicles.

[0142] The effects of the samples in this application's embodiments continued to improve: with the extension of the usage time (days 7, 14, and 28), the oil control effect steadily increased, and by day 28, the reduction rate of all samples reached over 70%. This indicates that the formula not only controls oil immediately but also regulates sebum secretion at the mechanistic level, achieving long-term care effects.

[0143] Furthermore, compared to the example, Comparative Example 1, which does not contain purulent melanin, showed slightly higher oil control data at all time points (especially on day 1 and day 28). This indicates that the addition of purulent melanin also has a certain effect on improving oil control.

[0144] The oil-control effects of Examples 1-4 were on par with Comparative Example 1 (without purulent melanin) and other comparative examples, and were far superior to the baseline (0%). This demonstrates that the present invention successfully integrates gray hair-covering ingredients into the shampoo system without sacrificing its core oil-control efficacy.

[0145] Furthermore, the oil-controlling effect trends and final results of all embodiments are highly consistent. This indicates that the oil-controlling active ingredient system of the present invention (zucchini seed extract, rosemary extract, etc.) is very effective and stable, and its efficacy is not significantly affected by minor changes in the masking ingredients.

[0146] More importantly, these data demonstrate that the two functions of "covering gray hair" and "controlling scalp oil" are compatible and synergistic in the formulation system of this application. This solves the problem in existing technologies where functional shampoos struggle to achieve multiple effects simultaneously.

[0147] 4. Gray hair cover test: Experimental principle: Untreated standard white human hair strands were used as the test matrix to simulate human gray hair. The shampoo sample to be tested was applied to the hair strands according to a prescribed procedure, and the ability of the sample to cover (color) gray hair after a certain number of uses was evaluated by visual assessment or colorimeter measurement.

[0148] Experimental instruments and materials: Main material: Standard white human hair bundles (from the same batch to ensure consistency).

[0149] Test samples: Shampoos from Examples 1 and 2, Examples 3-4, and Comparative Example 1.

[0150] Auxiliary equipment: constant temperature water bath, beaker, glass rod, electronic balance, timer, plastic clamp, drying rack.

[0151] Evaluation tools: digital camera (taking pictures under standard light and background), color chart, or a more precise colorimeter / spectrometer.

[0152] Experimental steps: Step S1: Hair Bundle Preparation Cut white human hair bundles into samples of the same weight (e.g., 3g) and length.

[0153] Thoroughly wet the hair strands with warm water and squeeze out any excess water.

[0154] Step S2: Product application Weigh out a sufficient and equal amount of test sample (5g) and apply it evenly to a wet hair strand.

[0155] Simulate the real shampooing process by gently massaging your hair strands with your fingers for 1-2 minutes to ensure the product evenly covers all hair strands.

[0156] Rinse with warm water (about 40°C) for 30 seconds to remove excess product.

[0157] Gently pat dry with a towel, then hang the hair on a drying rack to air dry at room temperature.

[0158] Step S3: Repeat Processing and Evaluation "Wash twice" process: After the hair strands are completely dry, repeat step S2 to complete the second shampoo.

[0159] Data collection: After the second shampoo and drying, all treated hair strands were arranged side by side with one untreated blank white hair strand.

[0160] Under a standard light source (such as a D65 light source), trained evaluators visually observe and record color changes, and / or use a colorimeter to measure the L* value (lightness) of the hair strand. The lower the L* value, the darker the color and the better the coverage.

[0161] Test results are attached to the instruction manual. Figure 3 .

[0162] As can be seen from the accompanying drawings, Embodiments 1 and 2 of this technical solution can provide some color coverage to the original white hair strands (blank areas) after two uses, but the color is very light and cannot completely cover the white hair. Embodiments 3 and 4 of this technical solution can provide a deeper color coverage and have a better effect on covering white hair. The comparison between Examples 1 and 2 and Examples 3 and 4 shows that a concentration of 0.6% polydihydroxyindole and 0.5%–0.6% purulent melanin provides superior coverage of gray hair. This indicates that a synergistic effect is better achieved within this ratio range. The positive charge and small particle size of purulent melanin may help polydihydroxyindole to better adsorb and fix onto negatively charged hair, resulting in a deeper color.

[0163] Furthermore, the formulation of Comparative Example 1 contains no purulent melanin at all, and it is closest to the blank group in the image, which also proves that purulent melanin and polydihydroxyindole produced a gray hair covering effect in the examples.

[0164] Furthermore, this technical solution is designed for "gradual coverage," rather than a one-time strong hair dyeing. Therefore, even in the best-performing embodiments 3 and 4, achieving "deeper color coverage" after two uses is a very ideal gradual effect. This aligns with the product's positioning as a daily shampoo; with continued use, the color gradually accumulates and deepens, avoiding the abruptness and unnaturalness of traditional hair dyes.

[0165] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A composition for covering gray hair, characterized by comprising, The composition for covering gray hair, by weight percentage, comprises: Polydihydroxyindole 0.05%-1%, melanin 0.05%-1%, sodium isoascorbate 0.02%-0.1%, surfactant 12%-18% (based on solids content), oil-controlling active ingredient 0.1%-0.2%, hair conditioner 0.5%-1.5%, balance water.

2. The composition for covering gray hair according to claim 1, characterized in that, The composition for covering gray hair, by weight percentage, comprises: Polydihydroxyindole 0.1%-0.9%, melanin 0.1%-0.9%, sodium isoascorbate 0.02%-0.1%, surfactant 12%-18% (based on solids content), oil-controlling active ingredient 0.1%-0.2%, hair conditioner 0.5%-1.5%, balance water.

3. The composition for covering gray hair according to claim 1, characterized in that, The composition for covering gray hair, by weight percentage, comprises: Polydihydroxyindole 0.1%-0.8%, melanin 0.1%-0.8%, sodium isoascorbate 0.02%-0.1%, surfactant 12%-18% (based on solids content), oil-controlling active ingredient 0.1%-0.2%, hair conditioner 0.5%-1.5%, balance water.

4. The composition for covering gray hair according to any one of claims 1-3, characterized in that, The ratio of the polydihydroxyindole to the purulent melanin is 0.1%: (0.1%~0.8%).

5. The composition for covering gray hair according to any one of claims 1 to 3, characterized by, The surfactant includes at least one of sodium C14-16 olefin sulfonate, sodium methyl cocoyl taurate, or sodium lauroyl amphoteric acetate.

6. The composition for covering gray hair according to any one of claims 1-3, characterized in that, The oil-controlling active ingredients include at least one of the following: zucchini seed extract, rosemary extract, tea tree oil, Melaleuca alternifolia leaf oil, or sunflower seed oil.

7. The composition for covering gray hair according to any one of claims 1-3, characterized in that, The hair conditioning agent includes at least one of the following: natural kelp extract or hydrolyzed keratin.

8. The composition for covering gray hair according to any one of claims 1-3, characterized in that, The composition for covering gray hair also includes a pH adjuster.

9. The composition for covering gray hair according to claim 8, characterized in that, The amount of the pH adjuster added is 0.1% to 1% by mass percentage.

10. A method for preparing the composition for covering gray hair according to any one of claims 1-9, characterized in that, include: Mix 0.05%-1% polydihydroxyindole, 0.05%-1% purulent melanin, 0.02%-0.1% sodium isoascorbate, 12%-18% surfactant (based on solid content), 0.1%-0.2% oil-controlling active ingredient, 0.5%-1.5% hair conditioner, and the remainder water thoroughly.

11. A shampoo, characterized in that, The composition for covering gray hair as described in any one of claims 1-9.

12. The shampoo according to claim 11, characterized in that, include: The amount of the composition for covering gray hair added to the shampoo is 1wt% to 25wt%.

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