Aromatic Amination Modification and Dyeing Methods for Cellulose Fibers

Abstract

This invention belongs to the field of dyeing and finishing, specifically relating to an aromatic amination modification method for cellulose fibers and its dyeing method, comprising the following steps: 1) Indocyanine anhydride modification of cellulose fibers: In a solvent, cellulose fibers undergo a modification reaction with indocyanine anhydride, followed by post-treatment to obtain indocyanine anhydride-modified cellulose; 2) Diazotization of indocyanine anhydride-modified cellulose: The indocyanine anhydride-modified cellulose obtained in step 1) is diazotized to obtain diazotized cellulose; 3) Coupling dyeing of diazotized cellulose: A coupling component solution is formed by mixing coupling components, sodium hydroxide, sodium carbonate, and water, and the diazotized cellulose fibers obtained in step 2) react with the coupling component solution to generate coupled dyed fibers. The dyeing method of this invention is suitable for dyeing cellulose fiber fabrics such as cotton, linen, bamboo, and viscose. It features low dyeing energy consumption, short dyeing time, bright colors, high wet fastness, and strong practicality.

Description

Technical Field

[0001] This invention belongs to the field of dyeing and finishing, specifically relating to an aromatic amination modification and dyeing method suitable for cellulose fibers. Background Technology

[0002] In the textile industry, cellulose fibers are one of the important raw materials. Cotton, linen, bamboo, and viscose fibers, in particular, contain a large number of hydroxyl groups in their molecular structure, which can undergo substitution reactions with reactive dyes to achieve reactive dyeing of fabrics. Meanwhile, in recent years, digital inkjet printing technology has developed rapidly, meeting market demands with its advantages of simple process, high printing precision, low energy consumption, and small footprint.

[0003] Reactive dyes are widely used for dyeing cellulosic fibers due to their comprehensive color spectrum, high wet fastness, and ease of use. However, the dyeing process involves high temperatures and energy consumption, and to achieve high dye exhaustion rates, a large amount of electrolyte (such as sodium chloride) is required for dyeing accelerators, resulting in a large amount of saline colored wastewater. Furthermore, when dyeing cellulosic fabrics, alkaline substances (such as sodium carbonate) are usually added for color fixation to promote the formation of covalent bonds between the dye and the fiber, thereby improving color fastness. However, the reactive groups of reactive dyes also suffer from problems such as easy hydrolysis and poor storage stability, with a fixation rate of only 50%-80%. The large amount of hydrolyzed dye entering the dyeing wastewater increases the difficulty of wastewater treatment and is detrimental to environmental protection. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an aromatic amination modification of cellulose fibers and a dyeing method thereof, namely, a diazotization-coupling dyeing method for cellulose fibers modified with indigo anhydride.

[0005] To address the aforementioned technical problems, this invention provides an aromatic amination modification and dyeing method suitable for cellulose fibers, comprising the following steps:

[0006] 1) Indigo anhydride-modified cellulose fibers:

[0007] Cellulose fibers were modified with indomethacin anhydride in a solvent. The amount of indomethacin anhydride was 1% to 10% of the mass of the cellulose fibers. The reaction temperature was 100±10℃ and the reaction time was 6±0.5h.

[0008] Then, post-processing is performed to obtain indigo anhydride-modified cellulose;

[0009] 2) Diazotization of cellulose modified with indomethacin:

[0010] The indocyanine anhydride-modified cellulose obtained in step 1) is diazotized to obtain diazotized cellulose;

[0011] 3) Coupling staining of diazotized cellulose:

[0012] A coupling component solution is formed by mixing a coupling component, sodium hydroxide, sodium carbonate, and water. The concentration of the coupling component solution is 2 ± 0.2 g / L, the concentration of sodium hydroxide is 0.1–2 g / L, and the concentration of sodium carbonate is 0.5–5 g / L.

[0013] The diazotized cellulose fibers obtained in step 2) are reacted with the coupling component solution to generate coupled dyed fibers; the coupling dyeing bath ratio is 1:20-100, that is, the cellulose fibers in step 1) : coupling component solution = 1g : 20-100mL.

[0014] Note that in this invention:

[0015] Cellulose fibers are modified by indocyanine anhydride. The hydroxyl groups on the cellulose fibers react with the indocyanine anhydride to introduce an aromatic primary amine structure into the cellulose fibers, resulting in indocyanine anhydride-modified cellulose. Subsequently, the indocyanine anhydride-modified cellulose is diazotized and directly reacts with the coupling component to generate a colored substance containing an azo structure, thereby achieving reactive staining of cellulose fibers.

[0016] As an improvement of the present invention on the aromatic amination modification of cellulose fibers and its dyeing method:

[0017] The coupling components are yellow coupling components, red coupling components, and blue coupling components;

[0018] The yellow coupling component is 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone, and its structural formula is:

[0019]

[0020] The red coupling component is an H acid, and its structural formula is:

[0021]

[0022] The blue coupling component is a disodium salt derivative of H acid, and its structural formula is:

[0023]

[0024] illustrate:

[0025] Of the above coupling components:

[0026] The yellow coupling component 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone and the red coupling component (H acid) are available through conventional commercial means.

[0027] The preparation method of the blue coupling component (H acid disodium salt derivative) includes the following steps:

[0028] (1) Diazotization reaction

[0029] Dissolve 1.38 g, 0.01 mol of m-nitroaniline in hydrochloric acid (10 mL, 0.015 mol); cool the mixture in an ice-water bath, then quickly add 0.012 mol, 2 mL of NaNO2 aqueous solution to the mixture, stir the mixture for 30 minutes, and stop the reaction when no color reaction occurs with Erich reagent, to obtain a diazonium salt solution;

[0030] (2) Coupling reaction

[0031] Add 0.015 mol of H acid monosodium salt and 1 g NaOH to 100 mL of water, filter to remove insoluble solids, and then add alkali to adjust the pH of the solution to 9-10 to obtain the coupling component;

[0032] The diazonium salt solution obtained in step (1) was slowly added to the above coupling component; then 1% NaOH aqueous solution was added to stir the reaction for 2 hours under pH 9-10 conditions; after the reaction was completed, HCl was added to adjust the pH to 1-2 to acidify the coupling product to form a precipitate, filtered, and the precipitate was washed 3 times, and then vacuum dried to constant weight to obtain the blue coupling component.

[0033]

[0034] As a further improvement to the aromatic amination modification and dyeing method of cellulose fibers of the present invention: the solvent in step 1) is N,N-dimethylformamide (DMF).

[0035] As a further improvement to the aromatic amination modification and dyeing method of cellulose fibers of the present invention: the post-treatment in step 1) is as follows:

[0036] First, the cellulose fibers are washed in hot water at 60±10℃ (for about 0.5 hours to remove indigo anhydride and its hydrolysis products adhering to the surface of the cellulose fibers), and then washed with cold water at 5-10℃ to obtain indigo anhydride-modified cellulose.

[0037] As a further improvement to the aromatic amination modification and dyeing method of cellulose fibers of the present invention, step 2):

[0038] The indocyanine anhydride-modified cellulose obtained in step 1) was placed in hydrochloric acid aqueous solution, and then NaNO2 aqueous solution was added (dropwise, with a dropwise addition time of about 5±1 min). The mixture was stirred at room temperature for 10 to 30 min. The molar ratio of HCl to NaNO2 was 1:(1.01±0.01), and (0.001±0.0001) mol of HCl was used for every 1 g of cellulose fiber.

[0039] Remove the reacted cellulose, wash it with water (until there are no solid particles on the fiber surface), and blow it dry to obtain diazotized cellulose for later use.

[0040] As a further improvement to the aromatic amination modification and dyeing method of cellulose fibers of the present invention, step 3):

[0041] Under continuous shaking, the diazotized cellulose obtained in step 2) is placed in the coupling component solution and soaked at room temperature for 10-20 minutes to achieve dyeing and generate coupled dyed fibers.

[0042] Then, the coupled dyed fibers are washed with water (to remove various substances adsorbed on the cellulose fibers) and dried to obtain dyed cellulose fibers.

[0043] As a further improvement to the aromatic amination modification and dyeing method of cellulose fibers applicable to the present invention, the cellulose fibers are any of the following:

[0044] Fabrics made from natural fibers, synthetic fibers, or blends of natural and synthetic fibers.

[0045] The natural fiber is any one of the following: cotton, linen, or bamboo fiber;

[0046] The artificial fiber is viscose fiber.

[0047] As a further improvement to the aromatic amination modification and dyeing method of cellulose fibers of the present invention, the water washing in step 3) is to alternately perform hot water washing at 60±10℃ and cold water washing at 5~10℃.

[0048] In this invention:

[0049] Step 1): Use 500±100ml of solvent for every 10g of cellulose fiber.

[0050] Concentrated hydrochloric acid containing 0.01 mol HCl was mixed with 15 ± 2 g of water to obtain a hydrochloric acid solution.

[0051] The amount of water used in the NaNO2 aqueous solution should be sufficient to dissolve the NaNO2.

[0052] Cellulose macromolecules are composed of β-D-glucose residues linked together by 1,4-glycosidic bonds. The two terminal glucose residues of the cellulose macromolecule contain a large number of hydroxyl groups. By modifying cellulose fibers with indocyanine anhydride, sufficient aromatic primary amine groups can be introduced into the cellulose fibers. Indocyanine anhydride-modified cellulose can be prepared into diazotized cellulose through a diazotization reaction, and then dyed with coupling components to achieve diazotization-coupling staining of indocyanine anhydride-modified cellulose fibers.

[0053] The diazotization-coupling staining mechanism of indigo anhydride-modified cellulose fibers is as follows:

[0054]

[0055] In this invention, the fabrics woven from natural fibers such as cotton, hemp, bamboo fiber, and artificial fibers such as viscose fiber, as well as the blended fabrics made from these fibers and the blended fabrics made from these fibers with chemical fibers or other types of natural fibers, are all commonly known fabrics and can be purchased on the market.

[0056] In this invention, the indocyanine anhydride (CAS: 118-48-9) used is commercially available.

[0057] In this invention, the hydrochloric acid, sodium nitrite, urea, sodium hydroxide, and sodium carbonate used are all commonly known chemical products that can be purchased commercially.

[0058] For cellulose fibers obtained by the dyeing method provided in this invention, the tests of their dry and wet rubbing fastness, washing fastness, and sublimation fastness shall be conducted in accordance with national standards commonly used in the field.

[0059] In this invention:

[0060] Modifying cellulose fibers with indigo anhydride allows for rapid dyeing at room temperature via a further diazotization coupling reaction; whereas existing reactive dye dyeing techniques require a longer reaction time.

[0061] Indigo anhydride-modified cellulose is diazotized, and the resulting diazotized cellulose forms a diazonium salt that is relatively stable and can be stored at room temperature. In contrast, existing technologies require diazonium salts to be stored at 0–5°C and cannot be stored for long periods; they must be prepared and used immediately.

[0062] Coupling dyeing can covalently bind with cellulose fibers under alkaline conditions at room temperature; while existing techniques require 0–5°C and alkaline conditions to achieve covalent bonding.

[0063] The beneficial effects of this invention are:

[0064] This invention successfully diazotizes cellulose fibers and then couples them with a coupling component for dyeing. In effect, it combines the synthesis process of azo dyes with the dyeing process of cellulose fibers, achieving near-room temperature dyeing, which greatly reduces dyeing energy consumption and avoids the discharge of colored wastewater during the dyeing process. This realizes an environmentally friendly green dyeing method, while also improving the rubbing fastness, washing fastness, and sublimation fastness of the dyed cellulose fibers, thereby enhancing the application performance of the products. It also provides a brand-new dyeing method for cellulose fibers.

[0065] The dyeing method provided by this invention can be used to dye cellulose fiber fabrics such as cotton, linen, bamboo, and viscose. The dyeing energy consumption is low, the dyeing time is short, the dyed fabrics have bright colors, high wet fastness, and strong practicality. Attached Figure Description

[0066] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0067] Figure 1 The image shows the yellow cellulose fabric (1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone) obtained in Example 1 and its K / S curve.

[0068] Figure 2 The image shows the red cellulose fabric (H acid) obtained in Example 2 and its K / S curve.

[0069] Figure 3 The image shows the blue cellulose fabric (disodium H-acid salt derivative) obtained in Example 3 and its K / S curve.

[0070] Figure 4 The K / S curve of the reactive dye-dyed cellulose fabric in Comparative Example 1 is shown.

[0071] Figure 5 The diagram shows the yellow cellulose fabric (1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone) of Comparative Example 2 and its K / S curve.

[0072] Figure 6 The image shows the yellow cellulose fabric (1-(4-sulfonophenyl)-3-methyl-5-pyrazolone) and its K / S curve for Comparative Example 3-1.

[0073] Figure 7 The red cellulose fabric (γ acid) of Comparative Example 3-2 and its K / S curve are shown.

[0074] Figure 8 The image shows the blue cellulose fabric (H acid derivative 1) of Comparative Example 3-3 and its K / S curve. Detailed Implementation

[0075] 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:

[0076] The room temperature in this invention refers to 20-30°C (preferably 25°C). The concentration of concentrated hydrochloric acid is 36% to 38%.

[0077] Example 1: An aromatic amination modification and dyeing method suitable for cellulose fibers:

[0078] The cellulose fiber is 10g of cotton fabric, and the dyeing bath ratio is 1:20. The following steps are performed in sequence:

[0079] 1) Cellulose fiber modification (using indigo anhydride to modify cotton fabrics):

[0080] 10g of cotton fabric was immersed in 500mL of N,N-dimethylformamide (DMF) solution containing 0.3g (0.0018mol) indomethacin anhydride and reacted at 100℃ for 6h to complete the modification. Then, it was washed in hot water at 60±10℃ for 0.5h, followed by washing with cold water at 5-10℃ to obtain the indomethacin anhydride-modified cotton fabric.

[0081] Note: The purpose of washing with hot and cold water is to remove unreacted indigo anhydride and its hydrolysis products from the cellulose fibers.

[0082] 2) Diazotization of indigo anhydride-modified cotton fabrics:

[0083] A hydrochloric acid solution is obtained by mixing concentrated hydrochloric acid containing 0.01 mol HCl with 15 g of water.

[0084] Prepare an aqueous solution of sodium nitrite by dissolving 0.0101 mol of sodium nitrite in 1 g of water;

[0085] The indocyanine anhydride-modified cotton fabric obtained in step 1) was dissolved in the above hydrochloric acid solution, and then an aqueous solution of sodium nitrite was slowly added dropwise (about 5 min). After stirring and reacting at room temperature for 10 min, excess nitrite was removed with urea. Then the fabric was taken out and washed with water (the washing was stopped when there were no solid particles on the surface of the cotton fabric). Then it was dried (until it was basically water-free, i.e., the moisture content was ≤2%) to obtain the diazotized cotton fabric.

[0086] Removing excess nitrite with urea is a standard technique. The method involves slowly adding urea, taking a small amount, and applying it to potassium iodide test paper. If the urea does not change color within 1-2 seconds, the excess nitrite has been removed.

[0087] 3) Coupling staining:

[0088] 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone was selected as the yellow coupling component, and its structural formula is as follows:

[0089]

[0090] A coupling component solution is formed by mixing 1-(2,5-dichloro-4-sulfonylphenyl)-3-methyl-5-pyrazolone, sodium hydroxide, sodium carbonate, and water. The concentration of 1-(2,5-dichloro-4-sulfonylphenyl)-3-methyl-5-pyrazolone 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.

[0091] Under continuous shaking, the diazotized cotton fabric obtained in step 2) is placed in 200 mL of coupling component solution and soaked at room temperature for 10 min to achieve dyeing. Then, it is alternately washed with hot water at 60±10℃ and cold water at 5~10℃, and finally dried (to constant weight) to obtain dyed cotton fabric A1.

[0092] Note: The above alternating hot and cold water washing is to remove various impurities that are easily adsorbed on the fabric, until the washing solution is colorless, at which point the washing process ends.

[0093] Experiment 1: The cotton fabric A1 used in Example 1 was tested according to the standards of "Color fastness to washing" (GB / T 3921-2008), "Color fastness to rubbing" (GB / T 3920-2008), and "Color fastness to dry heat" (GB / T 5718-1997).

[0094] K / S curve and fabric pattern diagram as follows Figure 1 The wavelength corresponding to the maximum K / S value point in the curve is 390nm, and the maximum K / S value for dyeing is 6.72. The dyed fabric has a dry rubbing fastness of 4-5, a wet rubbing fastness of 4-5, a soap washing fastness of 4-5, and a dry heat fastness of 4-5, with a relative fixation rate of 95.6%. This indicates that the fabric dyed using this method has excellent color fastness. The resulting dyed cotton fabric is a pale yellow.

[0095] Example 2: An aromatic amination modification and dyeing method suitable for cellulose fibers:

[0096] The cellulose fiber is 10g of hemp, and the dyeing bath ratio is 1:40. The following steps are performed in sequence:

[0097] 1) Cellulose fiber modification:

[0098] 10g of linen fabric was immersed in 500mL of N,N-dimethylformamide (DMF) solution containing 0.6g of indocyanine anhydride and reacted at 100℃ for 6h to complete the modification. Then, it was washed in hot water at 60±10℃ for 0.5h, followed by washing with cold water at 5~10℃ to obtain indocyanine anhydride modified linen fabric.

[0099] 2) Diazotization of indigo anhydride-modified linen fabrics:

[0100] The indigo anhydride-modified linen fabric obtained in step 1) was diazotized according to step 2) of Example 1 to obtain diazotized linen fabric.

[0101] 3) Coupling staining:

[0102] H acid was chosen as the red coupling component, and its structural formula is as follows:

[0103]

[0104] A coupling component solution is formed by mixing H acid, sodium hydroxide, sodium carbonate and water. The concentration of H acid 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.

[0105] Under continuous shaking, the diazotized linen fabric obtained in step 2) is placed in 400 mL of coupling component solution and soaked at room temperature for 10 min to achieve dyeing. Then, it is alternately washed with hot water at 60±10℃ and cold water at 5~10℃, and finally dried to obtain dyed linen fabric B1.

[0106] Experiment 2: The original linen fabric B1 used in Example 2 was tested according to the method described in Experiment 1:

[0107] K / S curve and fabric pattern diagram as follows Figure 2 The maximum K / S value point in the curve corresponds to a wavelength of 540 nm, and the maximum K / S value for dyeing is 6.78. The dyed fabric exhibits a dry rubbing fastness of 4-5, a wet rubbing fastness of 4-5, a soap washing fastness of 4-5, and a dry heat fastness of 4-5, with a relative fixation rate reaching 92.2%. This indicates that the fabric dyed using this method has excellent color fastness. The resulting dyed linen fabric is a rose-red color.

[0108] Example 3: An aromatic amination modification and dyeing method suitable for cellulose fibers:

[0109] The cellulose fiber is 10g of bamboo fiber, and the dyeing bath ratio is 1:50. The following steps are performed in sequence:

[0110] 1) Cellulose fiber modification:

[0111] 10g of bamboo fiber was immersed in 500mL of N,N-dimethylformamide (DMF) solution containing 0.9g of indocyanine anhydride and reacted at 100℃ for 6h to complete the modification. Then, it was washed in hot water at 60±10℃ for 0.5h, followed by washing with cold water at 5~10℃ to obtain indocyanine anhydride modified bamboo fiber.

[0112] 2) Diazotization of bamboo fibers by modifying them with indigo anhydride:

[0113] The bamboo fiber modified with indigo anhydride obtained in step 1) was diazotized according to step 2) of Example 1 to obtain diazotized bamboo fiber.

[0114] 3) Coupling staining:

[0115] The disodium salt derivative of H acid was selected as the blue coupling component, and its structural formula is as follows:

[0116]

[0117] A coupling component solution is formed by mixing a blue coupling component, sodium hydroxide, sodium carbonate, and water. The concentration of the blue 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.

[0118] Under continuous shaking, the diazotized bamboo fiber obtained in step 2) is placed in 500 mL of coupling component solution and soaked at room temperature for 10 min to achieve dyeing. Then, it is alternately washed with hot water at 60±10℃ and cold water at 5~10℃, and finally dried to obtain dyed bamboo fiber C1.

[0119] Experiment 3: The original bamboo fiber C1 used in Example 3 was tested according to the method described in Experiment 1:

[0120] K / S curve and fabric pattern diagram as follows Figure 3 The maximum K / S value point in the curve corresponds to a wavelength of 600 nm, and the maximum K / S value for dyeing is 6.21. The dyed fabric exhibits a dry rubbing fastness of 4-5, a wet rubbing fastness of 4-5, a soap washing fastness of 4-5, and a dry heat fastness of 4-5, with a relative fixation rate of 96.1%. This indicates that the fabric dyed using this method has excellent color fastness. The resulting dyed bamboo fiber is a deep blue color.

[0121] Comparative Example 1:

[0122] The cotton fabric (the same original cotton fabric used in Example 1) was dyed using a conventional dyeing method with reactive dyes. The reactive dye selected was Reactive Red KE-3B, whose structural formula is as follows:

[0123]

[0124] Dyeing is carried out according to the following process: dye concentration is 0.2g / L, sodium chloride is 70g / L, sodium carbonate is 10g / L, liquor ratio is 1:100, dyeing is carried out at room temperature, the temperature is increased to 70℃ at a rate of 1℃ / min and then held for 60min. After the holding is completed, the cotton fabric is taken out, washed with water and soaped several times, and then dried.

[0125] The K / S curve of the cotton fabric treated by the method described in Comparative Example 1 is as follows: Figure 4The wavelength corresponding to the maximum K / S value of the fabric sample in the curve graph is 540nm, and the maximum K / S value for dyeing is 8.04. Tested according to the method described in Experiment 1, the dyed fabric has a dry rubbing fastness of grade 4-5, a wet rubbing fastness of grade 4, a soap washing fastness of grade 4-5, a dry heat fastness of grade 4, and a relative fixation rate of 61.8%.

[0126] Note: If the dyeing temperature is changed from 70℃ to room temperature, the dyeing depth K / S will be only 1.42 and the dyeing rate will be only 28.92%.

[0127] The dye solution in Comparative Example 1 not only contains dye, but also contains a large amount of electrolytes (NaCl and Na2CO3), resulting in the discharge of colored saline wastewater and increasing the difficulty of wastewater treatment.

[0128] It can be seen that the temperature required for conventional reactive dyeing is much higher than that of the present invention, resulting in high energy consumption. Furthermore, the various properties of the fabric dyed by the present invention are superior to those of conventional reactive dyeing methods.

[0129] Comparative Example 2: The reaction temperature in step 1) of Example 1 was changed from "100℃" to "70℃", and the reaction time was changed from "6h" to "9h", with the rest being the same as in Example 1.

[0130] The test was conducted according to the method described in Experiment 1 above, and the results obtained are as follows: K / S curve and fabric pattern are shown below. Figure 5 The wavelength corresponding to the maximum K / S value point of the fabric sample in the curve is 390nm, and the maximum K / S value for dyeing is 5.51. The dyed fabric has a dry rubbing fastness of 4-5, a wet rubbing fastness of 4, a soap washing fastness of 4-5, a dry heat fastness of 4, and a relative fixation rate of 85.4%.

[0131] It can be seen that although the temperature was lowered by the method of Comparative Example 2, the reaction time was extended, and the various indicators of the dyed fabric of the present invention were better than those of the method described in Comparative Example 2.

[0132] Comparative Example 3-1: The yellow coupling component in Example 1 was changed from 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone to 1-(4-sulfonic acid phenyl)-3-methyl-5-pyrazolone, with the following structural formula; the rest was the same as in Example 1.

[0133]

[0134] The test was conducted according to the method described in Experiment 1 above, and the results obtained are as follows: K / S curve and fabric pattern are shown below. Figure 6The maximum K / S value point in the curve corresponds to a wavelength of 400 nm, and the maximum K / S value for dyeing is 5.77. The dyed fabric exhibits a dry rubbing fastness of 4-5, a wet rubbing fastness of 4, a soaping fastness of 4, a dry heat fastness of 4, and a relative fixation rate of 87.6%.

[0135] It can be seen that, although the coupling components used are different, the yellow coupling component used in Example 1 has better K / S, color fastness to soap washing, and color fixation rate than the yellow coupling component used in Comparative Example 3-1.

[0136] Comparative Example 3-2: The red coupling component in Example 2 was changed from H acid to γ ​​acid, with the following structural formula; the rest is the same as in Example 2.

[0137]

[0138] The test was conducted according to the method described in Experiment 2 above, and the results are as follows: K / S curve and fabric pattern are shown below. Figure 7 The maximum K / S value point of the fabric sample in the curve corresponds to a wavelength of 530nm, and the maximum K / S value for dyeing is 3.94. The dyed fabric has a dry rubbing fastness of 4-5, a wet rubbing fastness of 4, a soaping fastness of 4, a dry heat fastness of 4, and a relative fixation rate of 84.6%.

[0139] It can be seen that, although the coupling components used are different, the red coupling component used in Example 2 has better K / S, color fastness to soap washing, and color fixation rate than the red coupling component used in Comparative Example 3-2.

[0140] Comparative Example 3-3: The blue coupling component in Example 3 was changed from the disodium salt derivative of H acid to H acid derivative 1, with the following structural formula; the rest is the same as in Example 3.

[0141]

[0142] The test was conducted according to the method described in Experiment 3 above, and the results are as follows: K / S curve and fabric pattern are shown below. Figure 8 The maximum K / S value point in the curve corresponds to a wavelength of 600 nm, and the maximum K / S value for dyeing is 4.78. The dyed fabric has a dry rubbing fastness of 4-5, a wet rubbing fastness of 4, a soap washing fastness of 4, a dry heat fastness of 4, and a relative fixation rate of 85.1%.

[0143] It can be seen that, although the coupling components used are different, the blue coupling component used in Example 3 has better K / S, soap fastness, and fixation rate than the blue coupling component used in Comparative Example 3-3.

[0144] The comparison of the above cases is shown in Table 1 below.

[0145] Table 1

[0146]

[0147]

[0148] 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 dyeing method suitable for cellulose fibers, characterized in that... Includes the following steps: 1) Indocyanine anhydride-modified cellulose fibers: Cellulose fibers were modified with indomethacin anhydride in a solvent, with the amount of indomethacin anhydride being 1% to 10% of the mass of the cellulose fibers; the reaction temperature was 100±10℃ and the reaction time was 6±0.5h. Then, post-processing is performed to obtain indigo anhydride-modified cellulose fibers. The solvent is N,N-dimethylformamide; 2) Diazotization of cellulose fibers modified with indomethacin: The indocyanine anhydride obtained in step 1) was modified with diazotized cellulose fibers to obtain diazotized cellulose fibers. 3) Coupling staining of diazotized cellulose fibers: A coupling component solution is formed by mixing a coupling component, sodium hydroxide, sodium carbonate, and water. The concentration of the coupling component solution is 2 ± 0.2 g / L, the concentration of sodium hydroxide is 0.1–2 g / L, and the concentration of sodium carbonate is 0.5–5 g / L. The coupling component is a yellow coupling component, a red coupling component, or a blue coupling component; The yellow coupling component is 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone, and its structural formula is: ; The red coupling component is an H acid, and its structural formula is: ; The blue coupling component is a disodium salt derivative of H acid, and its structural formula is: ; The diazotized cellulose fibers obtained in step 2) are reacted with the coupling component solution to generate coupled dyed fibers; the coupling dyeing bath ratio is 1:20 to 100.

2. The dyeing method for cellulose fibers according to claim 1, characterized in that... The post-processing in step 1) is as follows: First, wash in hot water at 60±10℃, then wash in cold water at 5~10℃; to obtain indigo anhydride modified cellulose fibers.

3. The dyeing method for cellulose fibers according to claim 1 or 2, characterized in that... Step 2): The indocyanine anhydride-modified cellulose fibers obtained in step 1) were placed in an aqueous HCl solution, and then an aqueous NaNO2 solution was added. The mixture was stirred at room temperature for 10–30 min. The molar ratio of HCl to NaNO2 was 1:(1.01±0.01), and (0.001±0.0001) mol of HCl was used for every 1 g of cellulose fibers. The reacted cellulose fibers are removed, washed with water, and dried to obtain diazotized cellulose fibers.

4. The dyeing method for cellulose fibers according to claim 3, characterized in that... Step 3): Under continuous shaking, the diazotized cellulose fibers obtained in step 2) are placed in the coupling component solution and soaked at room temperature for 10-20 minutes to achieve dyeing and generate coupled dyed fibers. Then, the coupled dyed fibers are washed with water and dried to obtain dyed cellulose fibers.

5. The dyeing method for cellulose fibers according to claim 4, characterized in that... The cellulose fiber is any of the following fibers: Natural fibers and synthetic fibers.

6. The dyeing method for cellulose fibers according to claim 5, characterized in that: The natural fiber is any one of the following: cotton, linen, or bamboo fiber; The artificial fiber is viscose fiber.

7. The dyeing method for cellulose fibers according to claim 6, characterized in that... The water washing in step 3) consists of alternating hot water washing at 60±10℃ and cold water washing at 5~10℃.

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