Reactive dyeing method for black protein fibers based on coupled color development

Abstract

The present invention belongs to the field of dyeing and finishing. Disclosed is a reactive dyeing method for black protein fibers based on coupled color development. The method comprises the following steps: modifying protein fibers by using isatoic anhydride; diazotizing the obtained modified protein fibers by using nitrous acid, so as to obtain diazotized protein fibers; and reacting the diazotized protein fibers with an acidic solution containing a coupling component, so as to generate a colored substance containing an azo structure. Black protein fibers dyed by using the method exhibit a good relative fixation rate, up to 95%; and the dyed fibers have good color fastness and durability.

Description

Reactive staining method for black protein fibers based on coupling color development Technical Field

[0001] This invention belongs to the field of dyeing and finishing, and specifically relates to a reactive dyeing method for black protein fibers based on coupling color development. Background Technology

[0002] In the fashion and apparel industry, black is often an important color choice due to its classic and versatile nature. Black fabrics absorb almost all wavelengths of visible light and absorb more heat, making them ideal for insulation in cold environments. Ultraviolet (UV) rays have short wavelengths and high energy; prolonged exposure can damage the skin, so black fabrics provide protection by absorbing UV rays.

[0003] Currently, reactive dyes and acid dyes are commonly used for dyeing protein fibers such as silk and wool. Reactive dyes form covalent bonds with protein fibers, giving the dyed fabrics good wash and rubbing fastness. However, reactive dyes require high temperature and alkaline conditions for dyeing, which can damage protein fibers and affect fiber strength. Acid dyes bind to fibers through weak forces such as van der Waals forces, hydrogen bonds, and ionic bonds, resulting in lower wet treatment fastness. Since black is a composite color, it is difficult to achieve a deep, rich black effect on protein fiber fabrics using a single dye; usually, multiple dyes need to be used in combination.

[0004] The invention, "In-situ Diazotization-Coupling Staining Method for Indorubicin-Modified Protein Materials," patent number CN2023108126596, was an early patent application and authorization granted by the inventor's research team. This method involves a specific aromatic primary amination modification treatment of protein materials using indorubicin. The modified protein material undergoes an in-situ diazotization reaction in a nitrite environment, followed by a reaction with a specific coupling agent under alkaline conditions, resulting in the in-situ generation of an azo dye on the protein material, thus achieving coloring. The staining process is characterized by its near-room temperature reaction and low energy consumption.

[0005] The patent uses the following two coupling components:

[0006] The green coupling component is H-acid derivative 2, and its structure is as follows:

[0007] The black coupling component is H-acid derivative 3, and its structure is as follows:

[0008] Example 5 and corresponding Experiment 5 of the patent indicate that the color of the dyed castor silk fabric obtained by using H acid derivative 2 is dark green.

[0009] Example 6 and corresponding Experiment 6 of the patent indicate that using H-acid derivative 3, the dyed wool fabric is a light black color. The stripped dyed fabric has a K / S value of 16.5, which is an important indicator used to measure dyeing depth. Therefore, a deep black fabric cannot be obtained. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a reactive staining method for black protein fibers based on coupling color development.

[0011] To address the aforementioned technical problems, this invention provides a reactive staining method for black protein fibers based on coupling staining, comprising the following steps:

[0012] 1) Protein fiber modification:

[0013] Protein fibers are modified by indocyanine anhydride (resulting in the conversion of aliphatic amino groups in the protein fibers into aromatic primary amino groups), thereby obtaining modified protein fibers; the amount of indocyanine anhydride used is 7.5-8.5% (preferably 8%) of the mass of the protein fibers.

[0014] 2) Diazotization:

[0015] The modified protein fibers obtained in step 1) are diazotized with nitrous acid to obtain diazotized protein fibers.

[0016] 3) Coupling color development:

[0017] The diazotized protein fibers obtained in step 2) are reacted with an acidic solution containing coupling components (coupling component concentration 10±1 mmol / L) to generate a colored substance containing an azo structure; the coupling staining bath ratio is 1:20-100 (i.e., protein fibers in step 1: acidic solution containing coupling components = 1 g: 20-100 mL).

[0018] The pH of the acidic solution containing the coupling component is 2 ± 0.2;

[0019] The coupling components are H acid derivative 2 and H acid derivative 3;

[0020] H acid derivative 2:

[0021] H acid derivative 3:

[0022] As an improvement to the reactive staining method for black protein fibers based on coupling color development of the present invention, step 3) is as follows:

[0023] The coupling component, HCl, and water are mixed to form an acidic solution containing the coupling component, wherein the pH of the acidic solution containing the coupling component is 2±0.2 and the concentration of the coupling component is 10±1 mmol / L.

[0024] Under continuous oscillation, the diazotized protein fibers obtained in step 2) are immersed in an acidic solution containing coupling components at 0–35°C (preferably room temperature) for 20–40 min to achieve staining;

[0025] Then, the fibers are successively washed with soap (to remove various substances adsorbed on the protein fibers) and washed with water (to wash away the soap solution), followed by drying (drying at 40-60℃ for 20-40 minutes) to obtain black protein fibers.

[0026] As a further improvement to the reactive staining method for black protein fibers based on coupling color development of the present invention, the soaping in step 3) is as follows:

[0027] According to the bath ratio of 1:40-60 (i.e., 1g of protein fiber is used to wash 40-60mL of soap solution), the dyed protein fiber is placed in the soap solution and shaken and washed at 50-70℃ for 20-40 minutes.

[0028] The formula for the soaping solution is: sodium dodecylbenzenesulfonate 0.9-1.1 g / L, NaHCO3 0.9-1.1 g / L, and the balance is water.

[0029] As a further improvement to the reactive staining method for black protein fibers based on coupling color development of the present invention, step 1) is as follows:

[0030] Immerse 1g of protein fiber in 50±5ml of water, add Na2CO3 aqueous solution to adjust the pH to 8±0.2, then add DMF solution containing 0.075~0.085g (preferably 0.08g) of indomethacin anhydride, and shake the modification reaction at room temperature for 15~25min.

[0031] During the above modification reaction, the pH was maintained at 8 ± 0.2 by adding Na2CO3 aqueous solution dropwise.

[0032] Then remove and wash with water (to remove indigo anhydride from the protein fibers); the modified protein fibers are obtained.

[0033] Note: DMF can increase the solubility of indomethacin and thus improve leveling properties.

[0034] As a further improvement to the reactive staining method for black protein fibers based on coupling color development of the present invention, the DMF solution containing 0.075-0.085g (preferably 0.08g) indomethacin is composed of 0.075-0.085g (preferably 0.08g) indomethacin and 2±0.2mL of DMF.

[0035] The concentration of the Na2CO3 aqueous solution is 0.4–0.6 mol / L (preferably 0.5 mol / L).

[0036] As a further improvement to the reactive staining method for black protein fibers based on coupling color development of the present invention, step 2) is as follows:

[0037] The modified protein fibers obtained in step 1) are placed in an aqueous nitrite solution and stirred at room temperature for 15-25 minutes to carry out a diazotization reaction; the aqueous nitrite solution used for each 1g of protein fibers consists of 5.6-6.0 mmol HCl, 0.23-0.27 mmol NaNO2 and 28-31 mL water.

[0038] Then, remove and wash with water, and then dry (dry at 40-60℃ for 20-40 minutes) to obtain diazotized protein fibers.

[0039] As a further improvement to the reactive staining method for black protein fibers based on coupling color development of the present invention, the protein fibers are silk (mulberry silk) and wool.

[0040] For protein fibers obtained by the dyeing method provided by the present invention, the tests of their dry and wet rubbing fastness and soaping fastness shall be conducted in accordance with the national standards commonly used in the field.

[0041] This invention utilizes two coupling components mentioned in CN2023108126596—a green coupling component (H acid derivative 2) and a black coupling component (H acid derivative 3)—to couple with diazotized protein fibers under acidic conditions. By changing the coupling conditions, fabrics that were originally green (G1) and light black (B1) can be transformed into a deep black fabric while maintaining the structure of the coupling components. This innovative method not only improves the dyeing effect but also enhances the market competitiveness of dyed fabrics by using a single coupling component to dye the fabric black.

[0042] The reactive staining method for black protein fibers based on coupling color development of the present invention has the following technical advantages:

[0043] 1. This invention provides an innovative dyeing method that offers significant advantages over existing commercial black dyeing techniques for protein fibers. The method utilizes covalent bonds to ensure a strong bond between the dye and the protein fibers. More importantly, this method requires only one coupling component to achieve a deep, rich black dyeing effect, simplifying the dyeing process and reducing costs.

[0044] 2. The black protein fibers dyed using the method of this invention exhibit excellent relative fixation rate, up to 95%, and the dyed fibers possess outstanding color fastness and durability. The dyeing process is carried out under near-room temperature conditions. This mild dyeing environment reduces damage to the protein fibers during the dyeing process, protecting the natural structure and properties of the fibers. Attached Figure Description

[0045] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0046] Figure 1 shows the K / S curves and fabric pattern of the black mulberry silk fabric obtained in Example 1 and the black mulberry silk fabric after stripping.

[0047] Figure 2 shows the K / S curves and fabric sample diagrams of the black mulberry silk fabric and the black mulberry silk fabric after stripping color obtained in Example 2.

[0048] Figure 3 shows the K / S curves and fabric sample diagrams of the black mercerized wool fabric and the black mercerized wool fabric after stripping color obtained in Example 3.

[0049] Figure 4 shows the K / S curves and fabric sample diagrams of the black mercerized wool fabric and the black mercerized wool fabric after stripping color obtained in Example 4.

[0050] Figure 5 shows the K / S curves and fabric sample diagrams of the silk fabric before and after color removal obtained in Comparative Example 1.

[0051] Figure 6 shows the K / S curves and fabric sample diagrams of the wool fabric before and after stripping obtained in Comparative Example 2.

[0052] Figure 7 shows the K / S curves and fabric sample diagrams of the wool fabric before and after stripping obtained in Comparative Example 3.

[0053] Figure 8 shows a comparison of the K / S curves of the wool fabrics obtained in Example 4 and Comparative Example 3 after stripping. Detailed Implementation

[0054] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0055] The room temperature in this invention refers to 20–30°C (e.g., 25°C).

[0056] Example 1: A reactive dyeing method for black protein fiber fabrics based on coupling color development, comprising the following steps:

[0057] 1) Protein fiber modification, that is, modifying mulberry silk fabrics with indigo anhydride:

[0058] Immerse 1g of mulberry silk fabric in 50ml of water, add Na2CO3 aqueous solution (0.5mol / L) dropwise to make the solution pH 8, then add DMF solution containing indigo anhydride (0.08g indigo anhydride, 2ml DMF), and shake the reaction at room temperature for 20min.

[0059] During the above modification reaction, the pH of the reaction system was maintained at 8 by adding Na2CO3 aqueous solution (0.5 mol / L);

[0060] After the modification reaction is complete, the fabric is removed and washed with water (to remove indigo anhydride from the mulberry silk fabric); the modified mulberry silk fabric is obtained.

[0061] 2) Diazotization, that is, diazotizing the modified mulberry silk fabric:

[0062] At room temperature (25℃), 28 mL of water and 0.5 mL of hydrochloric acid aqueous solution (11.6 mol / L) were added to an Erlenmeyer flask. Then, 1 mL of sodium nitrite solution (0.25 mol / L) was added to the hydrochloric acid aqueous solution. After stirring evenly, the modified mulberry silk fabric obtained in step 1) was quickly immersed in the above solution and shaken for 20 min. Excess nitrite was removed with urea. Then, the fabric was taken out, washed with water, and dried in an oven at 50℃ for about 40 min to obtain diazotized mulberry silk fabric.

[0063] Instructions: Slowly add urea, then apply a small amount to potassium iodide test paper. If the paper does not change color within 1-2 seconds, it indicates that the excess nitrite has been removed.

[0064] 3) Coupling color development:

[0065] Choose H acid derivative 2, whose structural formula is:

[0066] Add 0.5 mmol of the coupling component H acid derivative 2 to 50 mL of water, and adjust the pH of the solution to 2 with hydrochloric acid aqueous solution (11.6 mol / L) to obtain an acidic solution containing the coupling component.

[0067] Under continuous oscillation, the diazotized modified silk fabric obtained in step 2) is immersed in an acidic solution containing coupling components, and shaken at room temperature (25℃) for 30 minutes to allow for a full coupling reaction, thereby achieving dyeing.

[0068] After the coupling reaction was completed, the dyed silk was removed, rinsed with water, and then soaped and washed with water. The soaping ratio was 1:50 (i.e., 1g of mulberry silk with 50mL of soaping solution), the soaping solution contained 1g / L NaHCO3 and 1g / L sodium dodecylbenzenesulfonate (the remainder being water), the soaping temperature was 60℃, and the soaping time was 30min. After washing with water at room temperature until the eluent was colorless (approximately 2min), the silk was placed in a 50℃ oven and dried for approximately 40min. This yielded a black mulberry silk fabric (Black 1).

[0069] Note: The above soaping and rinsing are to remove various substances that are freely adsorbed on the fabric until the washing solution is colorless, at which point the washing process ends.

[0070] Experiment 1: The black mulberry silk fabric (Black 1) obtained after treatment in Example 1 was subjected to DMF stripping. 1g of black mulberry silk fabric (Black 1) was placed in 100mL of DMF, heated to 100℃, and stripped for 30min. After stripping, the DMF on the fabric was washed with water, and dried in an oven at 50℃ for 40min. The stripped black mulberry silk fabric (Black 1 DMF stripped) was tested according to "Color fastness to washing GB / T3921—2008" and "Color fastness to rubbing GB / T 3920—2008".

[0071] Figure 1 shows the K / S curves and fabric sample diagrams of black mulberry silk fabric (Black 1) and black mulberry silk fabric after color stripping (Black 1DMF stripped). The wavelength corresponding to the maximum K / S value point of the fabric sample in the curve diagram is 610nm. The maximum K / S value of Black 1 is 16.5, and the maximum K / S value of Black 1DMF stripped is 16.1.

[0072] The dyed fabric has a dry rubbing color fastness of 4-5, a wet rubbing color fastness of 4-5, and a soap washing color fastness of 5, with a relative fixation rate of 97.58%. It can be seen that the black fabric dyed using this method has excellent color fastness.

[0073] Based on the comparison of the DMF stripping of Black 1 and Black 1 in Figure 1, it can be seen that a black dye is generated in situ on the silk. The dye forms a covalent bond with the silk and cannot be removed by the high temperature of DMF.

[0074] Example 2: A reactive staining method for black protein fibers based on coupling staining:

[0075] Replace 0.5 mmol of H acid derivative 2 in step 3) of Example 1 with 0.5 mmol of H acid derivative 3, and keep the rest the same as in Example 1; to obtain black mulberry silk fabric (black 2).

[0076] The structural formula of H acid derivative 3 is:

[0077] Experiment 2: The black mulberry silk fabric (Black 2) obtained after treatment in Example 2 was subjected to DMF stripping as described in Experiment 1; the stripped black mulberry silk fabric (Black 2 DMF stripped) was then tested as described in Experiment 1.

[0078] Figure 2 shows the K / S curves and fabric samples of black mulberry silk fabric (Black 2) and stripped black mulberry silk fabric (Black 2DMF stripped). The wavelength corresponding to the maximum K / S value of the fabric sample in the curve is 610nm. The maximum K / S value of Black 2 is 16.0, and the maximum K / S value of Black 2DMF stripped is 15.1. The color fastness to dry rubbing of the dyed fabric is grade 4-5, the color fastness to wet rubbing is grade 4-5, the color fastness to soaping is grade 5, and the relative fixation rate reaches 94.38%. It can be seen that the black fabric dyed using this method has excellent color fastness.

[0079] Based on the comparison of the DMF stripping of Black 2 and Black 2 in Figure 2, it can be seen that a black dye is generated in situ on the silk. The dye forms a covalent bond with the silk and cannot be removed by the high temperature of DMF.

[0080] Example 3: A reactive dyeing method for black protein fiber fabrics based on coupling color development:

[0081] Replace 1g of mulberry silk fabric in step 1) of Example 1 with 1g of mercerized wool fabric, and the rest is the same as in Example 1; to obtain black mercerized wool fabric (Black 3).

[0082] Experiment 3: The black mercerized wool fabric (Black 3) obtained after treatment in Example 3 was subjected to DMF stripping as described in Experiment 1; the stripped black mercerized wool fabric (Black 3 DMF stripped) was then tested as described in Experiment 1.

[0083] Figure 3 shows the K / S curves and fabric samples of black mercerized wool fabric (Black 3) and black mercerized wool fabric after stripping (Black 3DMF stripping). The wavelength corresponding to the maximum K / S value of the fabric sample in the curve is 610nm. The maximum K / S value of Black 3 is 31, and the maximum K / S value of Black 3DMF stripping is 29.5. The color fastness of the dyed fabric to dry rubbing is grade 4-5, the color fastness to wet rubbing is grade 4, and the color fastness to soaping is grade 5. The relative fixation rate reaches 95.16%, indicating that the black fabric dyed using this method has excellent color fastness.

[0084] Based on the comparison of the DMF stripping of Black 3 and Black 3 in Figure 3, it can be seen that a black dye is generated in situ on the silk. The dye forms a covalent bond with the silk and cannot be removed by the high temperature of DMF.

[0085] Example 4: A reactive dyeing method for black protein fiber fabrics based on coupling color development:

[0086] Replace 1g of mulberry silk fabric in step 1) of Example 2 with 1g of mercerized wool fabric, and the rest is the same as in Example 2; to obtain black mercerized wool fabric (black 4).

[0087] Experiment 4: The black mercerized wool fabric (Black 4) obtained after treatment in Example 4 was subjected to DMF stripping as described in Experiment 1; the stripped black mercerized wool fabric (Black 4 DMF stripped) was then tested as described in Experiment 1.

[0088] Figure 4 shows the K / S curves and fabric samples of black mercerized wool fabric (Black 4) and black mercerized wool fabric after stripping (Black 4 DMF stripping). The wavelength corresponding to the maximum K / S value of the fabric sample in the curve is 610 nm. The maximum K / S value of Black 4 is 27.7, and the maximum K / S value of Black 4 DMF stripping is 27.2. The color fastness of the dyed fabric to dry rubbing is grade 4-5, the color fastness to wet rubbing is grade 4, and the color fastness to soaping is grade 5. The relative fixation rate reaches 98.19%, indicating that the black fabric dyed using this method has excellent color fastness.

[0089] Based on the comparison of the DMF stripping of Black 4 and Black 4 in Figure 4, it can be seen that a black dye is generated in situ on the silk. The dye forms a covalent bond with the silk and cannot be removed by the high temperature of DMF.

[0090] Comparative Example 1:

[0091] The mulberry silk fabric (the same original mulberry silk fabric used in Example 1) was dyed using a reactive dye via conventional dyeing methods. The selected reactive dye was Reactive Black 5, whose structural formula is as follows:

[0092] The dyeing process is as follows: dye concentration 2.5 g / L, sodium sulfate 60 g / L, sodium carbonate 30 g / L, liquor ratio 1:20, dyeing at 30℃, heating to 70℃ at a certain rate (heating time 20 min), holding at 70℃ for 60 min, after which the silk fabric is removed, it is repeatedly soaped and washed with water, and dried in a 50℃ oven for 40 min to obtain black mulberry silk fabric (Black 5).

[0093] The black mulberry silk fabric (Black 5) obtained after treatment in Comparative Example 1 was subjected to DMF stripping as described in Experiment 1; the stripped black mulberry silk fabric (Black 5 DMF stripped) was then tested as described in Experiment 1.

[0094] The K / S curve of the silk fabric treated by the method described in Comparative Example 1 is shown in Figure 5. The wavelength corresponding to the maximum K / S value of the fabric sample in the curve is 580nm. The maximum K / S value after dyeing is 16.1, and the K / S value after stripping is 15.0. The dry rubbing fastness of the dyed fabric is grade 4-5, the wet rubbing fastness is grade 4-5, the soap washing fastness is grade 5, and the relative fixation rate reaches 93.17%.

[0095] Note: Changing the above "dyeing temperature is 70℃" to "dyeing temperature is room temperature" will result in a significant decrease in both the depth of color and the dye uptake rate.

[0096] It can be seen that the dyeing temperature required by this method is much higher than that of the present invention, resulting in high energy consumption. A large amount of alkali and salt need to be added during the dyeing process. Furthermore, the fabric dyed by the present invention has stronger absorption at short wavelengths (wider absorption peak) and a color that is more inclined towards black.

[0097] Comparative Example 2

[0098] Mercerized wool fabric (the same original mercerized wool fabric used in Example 3) was dyed using reactive dyes via conventional dyeing methods. The reactive dye selected was Reactive Black 5.

[0099] The dyeing process is as follows: dye concentration 2.5 g / L, sodium sulfate 60 g / L, sodium carbonate 30 g / L, liquor ratio 1:20, dyeing at 30℃, heating to 70℃ at a certain rate (heating time 20 min), holding at 70℃ for 60 min, after which the silk fabric is removed, it is soaped and washed several times, and dried in an oven at 50℃ for 40 min to obtain black mulberry silk fabric (Black 6).

[0100] The K / S curve of the wool fabric treated by the method described in Comparative Example 2 is shown in Figure 6. The wavelength corresponding to the maximum K / S value of the fabric sample in the curve is 570 nm. The maximum K / S value after dyeing is 29.8, and the K / S value after stripping is 29.6. According to the national standards "Color Fastness to Washing GB / T3921-2008" and "Color Fastness to Rubbing GB / T 3920-2008", the dyed fabric has a dry rubbing fastness of 4-5, a wet rubbing fastness of 4, a soap washing fastness of 5, and a relative fixation rate of 99.33%.

[0101] Note: Changing the above "dyeing temperature is 70℃" to "dyeing temperature is room temperature" will result in a significant decrease in both the depth of color and the dye uptake rate.

[0102] It can be seen that the dyeing temperature required by this method is much higher than that of the present invention, resulting in high energy consumption. A large amount of alkali and salt need to be added during the dyeing process. Furthermore, the fabric dyed by the present invention absorbs more strongly at short wavelengths and the color is more inclined towards black.

[0103] Table 1

[0104] The invention process also included the following comparisons:

[0105] Compared to step 3) of Example 4, the following changes are made: Step 3) is modified to be as described in CN2023108126596:

[0106] Specifically:

[0107] A coupling component solution is formed by mixing a black coupling component, sodium hydroxide, sodium carbonate, and water. The concentration of the black coupling component in the coupling component solution is 2 g / L, the concentration of sodium hydroxide is 0.2 g / L, and the concentration of sodium carbonate is 5 g / L.

[0108] Under continuous oscillation, the diazotized mercerized wool fabric obtained in step 2) is immersed in 500 mL of coupling component solution and reacted at room temperature for 30 min to achieve dyeing. Then, hot water washing and cold water washing are performed alternately, and finally, the fabric is dried to obtain the dyed mercerized wool fabric.

[0109] The rest is the same as in Example 4.

[0110] The subsequent testing methods were the same as in Experiment 4. The K / S curve of the wool fabric treated by the method described in Comparative Example 3 is shown in Figure 7. A comparison with Example 4 is shown in Table 2 below:

[0111] Table 2

[0112] It can be seen that the color depth of the acid-coupled dyed fabric of the present invention is much higher than that of the comparative example of the coupled dyed fabric. Moreover, the absorption of the present invention in 350-650nm exceeds 20, and the K / S curve is smoother. The comparison of the K / S curves of the two is shown in Figure 8.

[0113] Finally, it should be noted that the above examples are merely some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A reactive staining method for black protein fibers based on coupling staining, characterized in that... Includes the following steps: 1) Protein fiber modification: Protein fibers were modified with indocyanine anhydride to obtain modified protein fibers; the amount of indocyanine anhydride used was 7.5-8.5% of the mass of the protein fibers. 2) Diazotization: The modified protein fibers obtained in step 1) are diazotized with nitrous acid to obtain diazotized protein fibers. 3) Coupling color development: The diazotized protein fibers obtained in step 2) are reacted with an acidic solution containing coupling components to generate a colored substance containing an azo structure; the coupling staining bath ratio is 1:20 to 100. The pH of the acidic solution containing the coupling component is 2 ± 0.2; The coupling components are H acid derivative 2 and H acid derivative 3; H acid derivative 2: H acid derivative 3:

2. The reactive staining method for black protein fibers based on coupling color development according to claim 1, characterized in that... Step 3) is as follows: The coupling component, HCl, and water are mixed to form an acidic solution containing the coupling component, wherein the pH of the acidic solution containing the coupling component is 2±0.2 and the concentration of the coupling component is 10±1 mmol / L. Under continuous oscillation, the diazotized protein fibers obtained in step 2) are immersed in an acidic solution containing coupling components at 0–35°C for 20–40 min to achieve staining. Then, after being washed with soap and water, and subsequently dried, black protein fibers are obtained.

3. The reactive staining method for black protein fibers based on coupling color development according to claim 2, characterized in that... The soap washing in step 3) is as follows: At a liquor ratio of 1:40-60, the dyed protein fibers are placed in the soaping solution and washed with shaking at 50-70°C for 20-40 minutes. The formula for the soap washing solution is: sodium dodecylbenzenesulfonate 0.9-1.1 g / L, NaHCO3 0.9-1.1 g / L, and the balance is water.

4. The reactive staining method for black protein fibers based on coupling color development according to any one of claims 1 to 3, characterized in that... Step 1) is as follows: Immerse 1g of protein fiber in 50±5ml of water, add Na2CO3 aqueous solution to adjust the pH to 8±0.2, then add DMF solution containing 0.075~0.085g of indomethacin anhydride, and shake the modification reaction at room temperature for 15~25min. During the above modification reaction, the pH was maintained at 8 ± 0.2 by adding Na2CO3 aqueous solution dropwise. Then remove it and wash it with clean water; the modified protein fiber is obtained.

5. The reactive staining method for black protein fibers based on coupling color development according to claim 4, characterized in that: The DMF solution containing 0.075–0.085 g indomethacin is composed of 0.075–0.085 g indomethacin and 2 ± 0.2 mL of DMF. The concentration of the Na2CO3 aqueous solution is 0.4–0.6 mol / L.

6. The reactive staining method for black protein fibers based on coupling color development according to claim 5, characterized in that... Step 2) is as follows: The modified protein fibers obtained in step 1) are placed in an aqueous nitrite solution and stirred at room temperature for 15-25 minutes to carry out a diazotization reaction; the aqueous nitrite solution used for each 1g of protein fibers consists of 5.6-6.0 mmol HCl, 0.23-0.27 mmol NaNO2 and 28-31 mL water. After being removed, washed with water, and dried, diazotized protein fibers are obtained.

7. The reactive staining method for black protein fibers based on coupling color development according to any one of claims 1 to 6, characterized in that: The protein fibers are silk and wool.

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