A hair dyeing composition, its preparation and use

Abstract

The application discloses a hair dyeing composition, a preparation method and application thereof, and belongs to the field of hair dyeing. The hair dyeing composition comprises a synergist part, a silver-ammonia complex part and water. The synergist part comprises the following components in percentage by mass: a complex reducing agent 2-25%, ammonia water 3-5%, and a soluble copper salt 2-16%. The complex reducing agent is at least two of amino acid, a chelating agent, a carboxylic acid and a reducing sugar. The silver-ammonia complex part comprises the following components in percentage by mass: silver sulfate 1-6%, ammonia water 1-13%, and the balance is water. The hair dyeing composition has the effects of black hair protection and color protection, can make white hair turn black, keep the hair color after dyeing persistent and bright, and can avoid too deep or uneven color. The formula is safe and stable, and has excellent persistence.

Description

Technical Field

[0001] This invention relates to the field of cosmetic technology, and in particular to a hair dyeing composition, its preparation method, and its application. Background Technology

[0002] In recent years, silver ion hair dyeing has become increasingly popular. Silver ions have a smaller volume and can penetrate the hair cortex more easily. Utilizing the properties of silver ions, after repeated exposure to ultraviolet rays from sunlight, the silver ions gain electrons and undergo a reduction reaction, being reduced to nano-silver elemental. The black nano-silver elemental attaches to the hair cuticle, making the hair appear black, thus achieving the purpose of hair dyeing.

[0003] Because the size and shape of nano-silver vary, their scattering and absorption of light also differ, resulting in a color ranging from yellowish-brown to dark brown. The color gradually deepens as the concentration of silver ions increases, causing uncertainty in the color. On the other hand, due to the poor solubility of silver salts, the concentration of silver ions is low, or the stability of silver ions is poor. Coloring can only be achieved by repeated use; otherwise, uneven coloring and poor color fastness are likely to occur.

[0004] Currently, many hair dye products on the market illegally use silver nitrate as the main dyeing ingredient. For example, the literature "Analysis of the Efficacy Ingredients of 'White to Black' Hair Dye Products Based on Multispectral Technology" found that the actual effective ingredient in many such hair dye products is silver nitrate, which can easily pose serious safety risks to consumers. Based on the above risks, the development direction of many hair dye products has gradually shifted to other silver salts that are allowed to be added in the cosmetic field. For example, CN108697605B explored the use of silver salts such as silver sulfate, silver lactate, silver citrate, and silver oxide in hair dye products. By compounding silver sulfate with N-acetylsethionine in a certain proportion, the final coloring effect can be improved. However, it relies on increasing the concentration of silver ions to achieve a significant color deepening effect, which is not safe and stable enough. Summary of the Invention

[0005] The main objective of this invention is to provide a hair dye composition, its preparation method, and its application, aiming to solve the technical problem that the concentration of silver ions in existing hair dye products is too high and not safe and stable.

[0006] To achieve the above objectives, the first aspect of the present invention provides a hair dyeing composition comprising an synergist portion, a silver ammonia complex portion, and water;

[0007] The synergistic component comprises the following components by mass percentage: 2-25% complexing reducing agent, 3-5% ammonia, and 2-16% soluble copper salt; wherein the complexing reducing agent is at least two of amino acids, chelating agents, carboxylic acids, and reducing sugars;

[0008] The silver ammonia complex comprises the following components by mass percentage: 1-6% silver sulfate and 1-13% ammonia.

[0009] The remainder is water.

[0010] Further, it includes the following components by mass percentage: 3-6% silver sulfate, 3-12% soluble copper salt, 7-16% ammonia, 4-10% reducing agent, and the balance being water.

[0011] Furthermore, the reducing agent is at least two of the following: aspartic acid and its salts, glutamic acid and its salts, hydroxyethyl phosphate and its salts, citric acid and its salts, malic acid, glucose, dihydroxyacetone, and erythritol.

[0012] Furthermore, the reducing agent is a mixture of glutamic acid and citric acid in a mass ratio of 2:1 to 1:2.

[0013] Furthermore, the soluble copper salt is one or more of copper sulfate, sodium copper pyrrolidone carboxylate, copper gluconate, copper acetate, and copper acetylmethionine.

[0014] Another aspect of the present invention provides a method for preparing a hair dye composition, comprising the following steps:

[0015] S1: Mix the complexing reducing agent with a portion of ammonia water to obtain a mixture;

[0016] S2: Dissolve the soluble copper salt in water and mix it with the mixture to obtain the synergistic component;

[0017] S3: Disperse the silver sulfate in water, and add the remaining ammonia while stirring, until the silver sulfate is dissolved and transparent, to obtain the silver ammonia complex.

[0018] Another aspect of the present invention proposes the application of the hair dye composition in the preparation of hair darkening products.

[0019] Another aspect of the present invention provides a hair-darkening product, comprising the hair dyeing composition, and further comprising: water, glycerin, thickener, emulsifier, dispersant, surfactant, lubricant, fragrance and preservative;

[0020] The hair dye composition accounts for 5-10% of the mass of the hair darkening product.

[0021] Another aspect of the present invention provides a method for preparing a hair-darkening product, comprising the following steps:

[0022] (1) Add emulsifier, dispersant, surfactant and lubricant to oil phase pot, heat to 85°C, and stir evenly after dissolving;

[0023] (2) Add water, glycerin and thickener to the main pot, heat to 85°C, and stir well after dissolving;

[0024] (3) While stirring, draw the oil phase from step (1) into the main pot, keep it warm and stir for 30 minutes, then vacuum it, stir and cool it to 60°C.

[0025] (4) Add the combined reducing agent and ammonia water to the main pot, stir for 20 minutes, vacuum, stir and cool to 40°C, and then add the dissolved soluble copper salt.

[0026] (5) Add the premixed silver ammonia complex, water, flavoring and preservative to the main pot, stir evenly, and cool to obtain the final product.

[0027] Beneficial effects:

[0028] This invention discloses a hair dyeing composition in which silver sulfate and ammonia form a silver-ammonia complex, increasing the solubility of silver ions. Even at lower concentrations, silver sulfate can exert its hair-darkening and color-protecting effects, improving safety and stability. The reducing agents, including amino acids, carboxylic acids, and reducing sugars, possess reducing properties, reducing silver ions to elemental silver and promoting darker hair color. The chelating agent forms chelates with silver ions, stabilizing them and preventing precipitation. The amino acids, carboxylic acids, and ammonia work together to adjust the pH value, making the scalp feel gentle and non-irritating. Furthermore, the amino acids and carboxylic acids not only possess reducing properties, promoting the catalytic reduction of silver ions under light, but also act as complexing and stabilizing agents, forming complexes with silver ions or adsorbing onto the surface of silver particles to prevent aggregation. This limits the rate and quantity of silver particle formation on the hair, avoiding excessively dark or uneven color. The copper ions in the soluble copper salt have a catalytic effect in the hair dyeing composition, shortening the reaction time, accelerating coloring, and deepening the color.

[0029] The hair dyeing composition of the present invention contains silver sulfate, which can be stably present in the formula after being treated with ammonia water to form a silver ammonia complex. At the same time, by combining it with soluble copper salt and a coordinating reducing agent, the hair darkening speed and effect can be improved. Furthermore, the present invention has found that the ammonia water, coordinating reducing agent and soluble copper salt in the formula have a special ratio that makes the effect optimal and the formula most stable. The reducing property of the coordinating reducing agent and the soluble copper salt promote the reduction of silver ions to elemental silver.

[0030] The present invention discloses a method for preparing a hair dye composition. First, a reducing agent and a portion of ammonia are added to form a buffer system. Then, silver sulfate and the remaining ammonia are added to form a silver ammonia complex with a high pH value. The solubility of silver ions is maintained and stabilized, so that the highly reactive silver ammonia complex will not be quickly reduced to elemental silver after contact with other raw materials in the product, thus preventing the hair dye composition from failing. Attached Figure Description

[0031] Figure 1 This is a before-and-after comparison image of a test subject using the no-rinse hair conditioner prepared in Example 1 in this invention.

[0032] Figure 2 This is a before-and-after comparison image of another tester using the no-rinse hair conditioner prepared in Example 1 in this invention;

[0033] Figure 3 This is a before-and-after comparison image of a test subject using the no-rinse hair conditioner prepared in Example 3 in this invention;

[0034] Figure 4 This is a before-and-after comparison of the no-rinse hair conditioner prepared in Example 3 by another tester in this invention.

[0035] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0036] Unless otherwise specified, the experimental methods described in the following embodiments of the present invention are generally performed under conventional conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the embodiments are commercially available products.

[0037] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0038] The terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product, or device that includes a series of steps is not limited to the steps or modules listed, but may optionally include steps not listed, or may optionally include other steps inherent to such process, method, product, or device.

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of the invention.

[0040] The following embodiments further describe the present invention, but these embodiments are not intended to limit the scope of protection of the present invention.

[0041] An embodiment of the present invention provides a hair dyeing composition comprising an synergist portion, a silver ammonia complex portion, and water; the synergist portion comprises the following components by mass percentage: 2-25% complex reducing agent, 3-5% ammonia water, and 2-16% soluble copper salt; wherein the complex reducing agent is at least two of amino acids, chelating agents, carboxylic acids, and reducing sugars; the silver ammonia complex portion comprises the following components by mass percentage: 1-6% silver sulfate, 1-13% ammonia water; the balance being water.

[0042] Silver sulfate has a solubility of about 8 g / L in water at 20°C. The amount used in this invention can be effectively dissolved at room temperature, but the dissolution efficiency is low and requires long-term stirring, which is not conducive to actual production.

[0043] This invention discloses a hair dyeing composition in which silver sulfate and ammonia form a silver-ammonia complex, increasing the solubility of silver ions. Even at lower concentrations, silver sulfate can exert its hair-darkening and color-protecting effects, improving safety and stability. The reducing agents, including amino acids, carboxylic acids, and reducing sugars, possess reducing properties, reducing silver ions to elemental silver and promoting darker hair color. The chelating agent forms chelates with silver ions, stabilizing them and preventing precipitation. The amino acids, carboxylic acids, and ammonia work together to adjust the pH value, making the scalp feel gentle and non-irritating. Furthermore, the amino acids and carboxylic acids not only possess reducing properties, promoting the catalytic reduction of silver ions under light, but also act as complexing and stabilizing agents, forming complexes with silver ions or adsorbing onto the surface of silver particles to prevent aggregation. This limits the rate and quantity of silver particle formation on the hair, avoiding excessively dark or uneven color. The copper ions in the soluble copper salt have a catalytic effect in the hair dyeing composition, shortening the reaction time, accelerating coloring, and deepening the color.

[0044] The hair dyeing composition of the present invention contains silver sulfate, which can be stably present in the formula after being treated with ammonia water to form a silver ammonia complex. At the same time, by combining it with soluble copper salt and a coordinating reducing agent, the speed and effect of hair darkening can be improved. Furthermore, the present invention has discovered that there is a special ratio of ammonia water, coordinating reducing agent and soluble copper salt in the formula to achieve the best effect and the most stable formula. The reducing property of the coordinating reducing agent and the soluble copper salt promote the reduction of silver ions to elemental silver.

[0045] In one embodiment, the hair dye composition comprises the following components by mass percentage: 3-6% silver sulfate, 3-12% soluble copper salt, 7-16% ammonia, 4-10% reducing agent, and the balance being water.

[0046] In one embodiment, the reducing agent is at least two of the following: aspartic acid and its salts, glutamic acid and its salts, hydroxyethyl phosphate and its salts, citric acid and its salts, malic acid, glucose, dihydroxyacetone, and erythritol.

[0047] In the above embodiments, the reducing agent is a mixture of glutamic acid and citric acid in a mass ratio of 2:1 to 1:2. The acidic reducing agent resulting from the mixture of glutamic acid and citric acid can promote the photocatalytic reduction of silver ions, further improving the hair-darkening efficiency.

[0048] Preferably, the pH value is adjusted to 6-8.5 by combining ammonia with glutamic acid and citric acid, resulting in a mild and non-irritating product.

[0049] In one embodiment, the soluble copper salt is one or more selected from copper sulfate, sodium copper pyrrolidone carboxylate, copper gluconate, copper acetate, and copper acetylmethionine. The type of soluble copper salt is not limited, as long as it can ionize to produce copper ions.

[0050] Another aspect of the present invention provides a method for preparing a hair dye composition, the method comprising the following steps:

[0051] S1: The complex reducing agent is mixed with a portion of ammonia water at 75-85°C to obtain a mixture;

[0052] S2: Dissolve the soluble copper salt in water and mix it with the mixture to obtain the synergistic component;

[0053] S3: Disperse the silver sulfate in water, and add the remaining ammonia while stirring, until the silver sulfate is dissolved and transparent, to obtain the silver ammonia complex.

[0054] The present invention discloses a method for preparing a hair dye composition. First, a reducing agent and a portion of ammonia are added to form a buffer system with a pH value of 6 to 8.5. Then, silver sulfate and the remaining ammonia are added to form a silver ammonia complex with a relatively high pH value. The solubility of silver ions is maintained and they exist stably, so that the highly reactive silver ammonia complex will not be quickly reduced to elemental silver after contact with other raw materials in the product, thus causing the hair dye composition to fail.

[0055] In another aspect, this invention proposes the application of the hair dyeing composition in the preparation of hair-darkening products. Preferably, the dosage form of the hair-darkening product includes solutions, creams, gels, lotions, etc.

[0056] The present invention also proposes a hair-darkening product, comprising the hair dyeing composition, and further comprising: water, glycerin, thickener, emulsifier, dispersant, surfactant, lubricant, fragrance and preservative;

[0057] The hair dye composition accounts for 5-10% of the mass of the hair darkening product.

[0058] Another aspect of the present invention provides a method for preparing a hair-darkening product, the method comprising the following steps:

[0059] (1) Add emulsifier, dispersant, surfactant and lubricant to oil phase pot, heat to 85°C, and stir evenly after dissolving;

[0060] (2) Add water, glycerin and thickener to the main pot, heat to 85°C, and stir well after dissolving;

[0061] (3) While stirring, draw the oil phase from step (1) into the main pot, keep it warm and stir for 30 minutes, then vacuum it, stir and cool it to 60°C.

[0062] (4) Add the combined reducing agent and ammonia water to the main pot, stir for 20 minutes, vacuum, stir and cool to 40°C, and then add the dissolved soluble copper salt.

[0063] (5) Add the premixed silver ammonia complex, water, flavoring and preservative to the main pot, stir evenly, and cool to obtain the final product.

[0064] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments are merely illustrative of the present invention and should not be construed as limiting the invention.

[0065] The following sources of raw materials are for illustrative purposes only:

[0066] Analytical grade silver sulfate: Guangdong Xilong Chemical Co., Ltd.;

[0067] Analytical pure ammonia solution: Guangdong Xilong Chemical Co., Ltd.;

[0068] Analytical grade copper sulfate: Guangdong Xilong Chemical Co., Ltd.;

[0069] Citric acid: Weifang Yingxuan New Materials Co., Ltd.;

[0070] Glutamic acid: Changsha Kesaiqi Biotechnology Co., Ltd.;

[0071] Exfoliated Asian natural gray hair bundles: Shanghai Canyu Trading Co., Ltd.;

[0072] All other raw materials can be purchased through legitimate commercial channels.

[0073] The raw materials and components used in the hair dyeing composition in the examples are shown in Table 1:

[0074] Table 1. Raw materials and components used in hair dyeing compositions.

[0075]

[0076] Comparative Example 1

[0077] The difference between this comparative example and Example 1 is that copper sulfate is replaced with ferrous sulfate.

[0078] Comparative Example 2

[0079] The difference between this comparative example and Example 1 is that all glutamic acid was replaced with citric acid.

[0080] Comparative Example 3

[0081] The difference between this comparative example and Example 1 is that citric acid was completely replaced with glutamic acid.

[0082] Comparative Example 4

[0083] The difference between this comparative example and Example 1 is that it does not contain ammonia, and sodium hydroxide is used to adjust the pH to be consistent with that of Example 1.

[0084] Comparative Example 5

[0085] The difference between this comparative example and Example 1 is that the amount of copper sulfate added is 15% and the amount of silver sulfate added is 0.5%.

[0086] Comparative Example 6

[0087] The difference between this comparative example and Example 1 is that the mass fraction of citric acid and glutamic acid added is 1%.

[0088] Comparative Example 7

[0089] The difference between this comparative example and Example 1 is that glutamic acid is not added to the C-phase synergist portion.

[0090] Comparative Example 8

[0091] The formulation of this comparative example is no different from that of Example 1. The difference is that both the C-phase synergist and the D-phase complex were added at 75-85°C when preparing the leave-in conditioner.

[0092] Except for Comparative Example 8, the other comparative examples and Examples 1-7 were prepared using the corresponding proportions of raw materials according to the preparation method of leave-in conditioner. The basic formula of the leave-in conditioner is shown in Table 2 below:

[0093] Table 2 Basic Formula of Leave-in Conditioner

[0094]

[0095]

[0096] The leave-in hair conditioners prepared in Examples 1-7 and the samples obtained in Comparative Examples 1-8 were subjected to the following experiments:

[0097] Experiment 1 Stability Experiment

[0098] The leave-in conditioners prepared in Examples 1-7 and the samples obtained in Comparative Examples 1-8 were placed in environments of room temperature, -18℃, and 50℃, respectively. If, within one month, phenomena such as layering, seepage, emulsification, significant color changes, and deterioration in the hairspring test results occurred, the stability was deemed unqualified. The stability results are shown in the table below:

[0099] Table 3 Stability Test Results

[0100]

[0101]

[0102] The experimental results above show that the sample in Comparative Example 1 exhibited significant discoloration and decreased effectiveness at room temperature, possibly due to the reducing properties of ferrous sulfate, which directly reduced silver ions to elemental silver in the material, resulting in poorer performance. Comparative Examples 3, 5, and 6 showed significant discoloration and decreased effectiveness in the high-temperature stability test, possibly because the amount and type of reducing agent affected the ease of reaction with silver ions. When the amount of reducing agent was relatively high, some excess reducing agent readily reacted with silver ions at high temperatures, reducing them to elemental silver and thus rendering the solution ineffective. However, a decrease in citric acid content also reduced effectiveness. Combining the results from Comparative Example 3 (containing only glutamic acid), Comparative Example 2 (containing only citric acid), and Comparative Example 7 (without glutamic acid), it can be seen that: a suitable amount of citric acid provides a stabilizing effect; while glutamic acid alone, due to its strong reducing properties, caused severe discoloration and rapid ineffectiveness. Comparative Example 4 demonstrates that sodium hydroxide cannot completely dissolve silver sulfate, and even with the same pH value, it cannot replace ammonia.

[0103] The leave-in hair conditioner prepared from the dyeing compositions used in Examples 1 to 7 of the present invention has all key components that can remain stable in the system for a long time and does not have high requirements for ambient temperature.

[0104] Experiment 2: In vitro hair bundle test

[0105] 1. The leave-in conditioner prepared in Examples 1 to 7 and the samples obtained in Comparative Examples 1 to 8 were used to dye isolated natural Asian white hair strands. The single dyeing process was as follows: 1g of leave-in conditioner or sample that had been left at room temperature for 30 days was applied to the white hair strands, and then placed outdoors in sunlight for 20 minutes. After rinsing with clean water and drying the hair, the coloring effect was observed.

[0106] Record the coloring and rinsing of each leave-in conditioner and sample, repeating 5 times and comparing the colors. Use a numerical value from 0 to 5: 0 represents white, 1 represents off-white, 2 represents light brown, 3 represents reddish-brown, 4 represents dark brown, and 5 represents brownish-black. The results are shown in Table 4. If the effect after one dyeing session reaches 2 (brown), the coloring is considered successful; if the effect after dyeing is 0 or 1, the coloring effect is considered poor and unsuccessful.

[0107] II. The hair samples obtained from Examples 1-7 and Comparative Examples 1-8 after being dyed 20 times were washed separately. The washing process for each wash was as follows: the hair was washed with water at 40°C and regular shampoo, with 1g of shampoo used per strand. After washing for 2 minutes, the hair was rinsed clean and dried. The color of the hair after washing was recorded using a numerical value from 0 to 5: 0 represents white, 1 represents grayish-white, 2 represents light brown, 3 represents reddish-brown, 4 represents dark brown, and 5 represents brownish-black. The observation results are shown in Table 4.

[0108] Table 4. Scoring of hair coloring effect for each example and comparative example.

[0109]

[0110] As can be seen from the table above, the concentration of silver sulfate, copper sulfate, reducing agent, and ammonia are all key factors in solving the technical problems of this invention. The components in this invention have a mutual constraint relationship through special proportions, and the hair dyeing effect can be improved within a suitable proportion range.

[0111] Comparisons of Examples 1 and 7 and Comparative Examples 2 and 3 show that replacing the same type of coordination reducing agent has no effect on the system. However, removing any coordination reducing agent significantly reduces the hair dyeing effect, and removing carboxylic acids and retaining only amino acids results in a more severe decrease. It is speculated that this is because citric acid has a weaker reducing power for silver ions than glutamic acid, leading to premature reaction and a decrease in effect. Furthermore, in Comparative Examples 6 and 7, increasing or decreasing the amount of coordination reducing agent weakens the effect, with a mechanism similar to that of Comparative Examples 2 and 3.

[0112] In Comparative Example 4, silver sulfate turned into black silver oxide under alkaline conditions. Silver oxide is almost insoluble in the system and cannot form a soluble silver ammonia complex due to the lack of ammonium ions, thus resulting in a poorer effect.

[0113] In Comparative Example 5, the excessive copper sulfate content reduced the hair dyeing effect. This may be because excess copper sulfate competes with silver ions for adsorption sites on the hair, resulting in a decrease in the actual amount of silver ions bound to the hair and ultimately a poorer effect. Comparative Example 8 shows that the preparation method of the hair dyeing composition of this invention is unique in practical applications. Direct addition at high temperatures leads to a poorer effect, possibly because the high temperature results in higher activity of the reducing agent, prematurely reducing the silver ions.

[0114] The leave-in hair conditioner prepared from the dyeing compositions used in Examples 1 to 7 of the present invention is superior in terms of coloring effect, durability and stability. Among them, Examples 1 and 7 have the best effect.

[0115] Experiment 3 Human Effect Test

[0116] Twenty participants with gray hair and twenty with brown hair were selected, all using the leave-in conditioner from Example 1. The two groups rated the color-enhancing effect of the leave-in conditioner from Example 1 or the color-protecting effect of the leave-in conditioner from Example 3, on a scale of 1 to 10, where 1 represents very poor and 10 represents very good. Participants were required to use the conditioner continuously for two weeks as part of their daily routine, following the instructions for use as a leave-in conditioner. Follow-up visits were conducted after two weeks to collect scores and photos. During the treatment period, participants were not allowed to change the shampoo sample and were prohibited from using hair care products such as conditioner. The scoring results are shown in Table 5.

[0117] Table 5. Human Effect Test Scoring Results

[0118]

[0119]

[0120] As can be seen from the table above, the leave-in conditioner made with the composition obtained by the technical solution of the present invention has obvious effects on white-to-black coloring and brown color protection. (Refer to the accompanying drawings.) Figure 1 and Figure 2 The photos show before and after comparisons of test subjects 6 and 13 using the leave-in conditioner prepared in Example 1. Figure 3 and Figure 4 Before and after comparison images of test subjects 22 and 35 using the leave-in conditioner prepared in Example 3, it can be seen that the leave-in conditioner prepared using the hair dyeing composition of the present invention can achieve obvious white-to-black and brown color protection effects.

[0121] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A hair dyeing composition, characterized in that, It includes the synergist component, the silver ammonia complex component, and water; The synergistic component comprises the following components by mass percentage: 2-25% complexing reducing agent, 3-5% ammonia, and 2-16% soluble copper salt; wherein the complexing reducing agent is at least two of amino acids, chelating agents, carboxylic acids, and reducing sugars; The silver ammonia complex comprises the following components by mass percentage: 1-6% silver sulfate and 1-13% ammonia. The remainder is water.

2. The hair dyeing composition according to claim 1, characterized in that, It includes the following components by mass percentage: 3-6% silver sulfate, 3-12% soluble copper salt, 7-16% ammonia, 4-10% reducing agent, and the balance being water.

3. The hair dyeing composition according to claim 1 or 2, characterized in that, The reducing agent is at least two of the following: aspartic acid and its salts, glutamic acid and its salts, hydroxyethyl phosphate and its salts, citric acid and its salts, malic acid, glucose, dihydroxyacetone, and erythritol.

4. The hair dyeing composition according to claim 3, characterized in that, The reducing agent is a mixture of glutamic acid and citric acid in a mass ratio of 2:1 to 1:

2.

5. The hair dyeing composition according to claim 1, characterized in that, The soluble copper salt is one or more of copper sulfate, sodium copper pyrrolidone carboxylate, copper gluconate, copper acetate, and copper acetylmethionine.

6. A method for preparing a hair dye composition according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Mix the complexing reducing agent with a portion of ammonia water to obtain a mixture; S2: Dissolve the soluble copper salt in water and mix it with the mixture to obtain the synergistic component; S3: Disperse the silver sulfate in water, and add the remaining ammonia while stirring, until the silver sulfate is dissolved and transparent, to obtain the silver ammonia complex.

7. The use of the hair dye composition according to any one of claims 1 to 5 in the preparation of hair darkening products.

8. A hair-darkening product, characterized in that, The hair dye composition comprising any one of claims 1 to 5 further comprises water, glycerin, thickener, emulsifier, dispersant, surfactant, lubricant, fragrance and preservative; The hair dye composition accounts for 5-10% of the mass of the hair darkening product.

9. A method for preparing a hair-darkening product according to claim 8, characterized in that, Includes the following steps: (1) Add emulsifier, dispersant, surfactant and lubricant to oil phase pot, heat to 85°C, and stir evenly after dissolving; (2) Add water, glycerin and thickener to the main pot, heat to 85°C, and stir well after dissolving; (3) While stirring, draw the oil phase from step (1) into the main pot, keep it warm and stir for 30 minutes, then vacuum it, stir and cool it to 60°C. (4) Add the combined reducing agent and ammonia water to the main pot, stir for 20 minutes, vacuum, stir and cool to 40°C, and then add the dissolved soluble copper salt. (5) Add the premixed silver ammonia complex, water, flavoring and preservative to the main pot, stir evenly, and cool to obtain the final product.

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