Aryl primary amination modification and diazotization-coupling dyeing method of cellulose fiber

Abstract

The invention belongs to the field of dyeing and finishing, and particularly relates to an aromatic primary amination modification and diazotization-coupling dyeing method of cellulosic fibers. Comprising the following steps: 1) modifying cellulose fibers by using an ester-type primary aromatic amination reagent: in water containing sodium carbonate, carrying out primary aromatic amination modification reaction on the cellulose fibers by using the ester-type primary aromatic amination reagent to obtain primary aromatic aminated cellulose; (2) diazotization of the primary aromatic aminated cellulose: diazotizing the primary aromatic aminated cellulose obtained in the step (1) to obtain diazotized cellulose; and 3) coupling dyeing of the diazotized cellulose: adding the diazotized cellulose into the coupling component solution to carry out a coupling chromogenic reaction so as to generate the coupling chromogenic fiber. The dyeing method provided by the invention can be used for dyeing cellulose fiber fabrics such as cotton, hemp, bamboo, viscose and the like, the dyeing energy consumption is low, the time is short, and the dyed fabrics are bright in colored light, relatively high in moisture-proof treatment color fastness and strong in practicability. The alkali resistance of the dyed fabric is high.

Description

Technical Field

[0001] The invention belongs to the field of dyeing and finishing, and particularly relates to a method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof. Background Art

[0002] Cellulose fibers (including cotton, linen, viscose, etc.) are important textile raw materials. The hydroxyl groups present in large quantities in their molecular structures can undergo electrophilic substitution reactions with the reactive groups in reactive dyes, thereby achieving reactive dyeing of fabrics. Reactive dyes are widely used in the dyeing of cellulose fibers because they have advantages such as a complete color spectrum, high wet fastness, and ease of use. Due to the repulsive force between the reactive dyes and the fibers, a large amount of salt needs to be added during the dyeing process to promote dyeing, thereby producing colored wastewater with a high salt content. In addition, reactive dyes need to undergo a fixation reaction with the fibers under high temperature alkaline conditions to form covalent bonds to improve color fastness, thus also causing high energy consumption problems. In addition, the active groups of reactive dyes also have the problems of easy hydrolysis and poor storage stability, resulting in low dye utilization rates. A large amount of hydrolyzed dyes increase the difficulty of wastewater treatment.

[0003] In the early work of this industry, a diazotization-coupling dyeing method for isatoic anhydride-modified cellulose fibers was developed, and a corresponding invention patent "Aromatic Amination Modification and Dyeing Method for Cellulose Fibers" (CN117306277A) was applied for. This method still has shortcomings such as the high modification temperature of the aromatic amination reagent isatoic anhydride (100±10°C, resulting in high energy consumption), low modification rate (related to K / S, its value is generally lower than 8), and long modification time (6±0.5 h). In addition, the dyed fabric obtained by this method has a dyed chromogen connected to the cotton fiber through an ester bond, and the alkali stability is relatively low, resulting in poor alkali resistance of the final dyed fabric. Explanation: Since detergents are mostly alkaline during the washing process and the washing process requires heating, it is necessary to ensure the alkali resistance of the dyed fabric. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof, namely, a method for aromatic primary amination modification of cellulose fibers using an ester-type aromatic primary amination reagent and diazotization-coupling dyeing thereof.

[0005] In order to solve the above technical problems, the present invention provides a method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof, comprising the following steps:

[0006] 1) Ester-type aromatic amination reagent modified cellulose fiber:

[0007] In water containing sodium carbonate, the cellulose fibers are subjected to an aromatic amination modification reaction using an ester-type aromatic amination reagent, wherein the amount of the ester-type aromatic amination reagent is 0.5-5% of the mass of the cellulose fibers, the ratio of sodium carbonate to water is 5-10 g / L, the reaction temperature is 60±10° C., and the reaction time is 0.5-2 h;

[0008] The cellulose fibers after the reaction are washed and named as aromatic primary aminated cellulose;

[0009] Note: The above washing is: first clean in 40±10℃ hot water, then rinse with 5~10℃ clean water;

[0010] 2) Diazotization of aromatic aminated cellulose:

[0011] Diazotizing the aromatic primary aminated cellulose obtained in step 1) to obtain diazotized cellulose;

[0012] 3) Coupled dyeing of diazotized cellulose;

[0013] The coupling component is placed in water, and then a buffer solution with a pH of 9±0.2 is added to form a coupling component solution; in the coupling component solution, the concentration of the coupling component is 2±0.2 g / L;

[0014] The diazotized cellulose obtained in step 2) is added to the coupling component solution to carry out a coupling color reaction, thereby generating a coupled color fiber; the coupling color bath ratio is 1:20-100 (i.e., cellulose fiber in step 1: coupling component solution = 1 g: 20-100 mL), and the color reaction is carried out for 0.5-1 h.

[0015] It is explained that in the present invention: cellulose fibers are subjected to aromatic amination modification using an ester-type aromatic amination reagent, and the hydroxyl groups on the cellulose fibers react with the ester-type aromatic amination reagent, thereby introducing an aromatic amine structure into the cellulose fibers to obtain aromatic aminated cellulose; subsequently, the aromatic aminated cellulose is directly reacted with a coupling component after diazotization to form a colored substance containing an azo structure, thereby achieving reactive dyeing of the cellulose fibers.

[0016] As an improvement of the aromatic primary amination modification of cellulose fibers and the diazotization-coupling dyeing method thereof of the present invention:

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

[0018] The yellow coupling component is 1-(4-sulfonate phenyl)-3-carboxy-5-pyrazolone, and its structure is:

[0019]

[0020] The red coupling component is acetyl H acid, and its structure is:

[0021]

[0022] The blue coupling component is an H acid couple, and its structure is:

[0023]

[0024] illustrate:

[0025] The above coupling components are all known compounds;

[0026] The yellow coupling component (1-(4-sulfonic acid phenyl)-3-carboxy-5-pyrazolone) and the red coupling component (acetyl H acid) can be obtained in conventional commercial forms.

[0027] The blue coupling component (H acid couple) is disclosed in the published "Coloration Technology. 2020; 136: 288-295." The preparation method can be, for example, the following steps:

[0028] (1) Diazotization reaction

[0029] Dissolve p-cyanoaniline (0.01 mol) in hydrochloric acid solution (10 mL, 0.015 mol); cool in an ice-water bath, then quickly add aqueous NaNO2 solution (0.012 mol, 2 mL) and stir for 30 minutes to complete the reaction to obtain a diazonium salt solution;

[0030] (2) Coupling reaction

[0031] Add 0.015 mol of H acid monosodium salt to 100 mL of water, and then adjust the solution pH to 4-5 to obtain the coupling component;

[0032] The diazonium salt solution obtained in step (1) was slowly added (addition time was about 5 minutes) to the above coupling component; 1% NaOH aqueous solution was then added to adjust the pH to 4-5 and stirred for 2 hours; after the reaction was completed, HCl was added to adjust the pH to 1-2 to acidify the coupling product to form a precipitate, which was filtered and washed with water 3 times, and then dried at 60°C to constant weight to obtain a blue coupling component.

[0033]

[0034] As a further improvement of the aromatic primary amination modification of cellulose fibers and the diazotization-coupling dyeing method thereof of the present invention, the step 1):

[0035] The ester-type aromatic primary amination reagent is any of the following:

[0036] Meta-ester, its structural formula is:

[0037] Para-ester, its structural formula is:

[0038] The above-mentioned ester-type primary aromatic amination reagents can all be purchased commercially.

[0039] As a further improvement of the aromatic primary amination modification of cellulose fibers and the diazotization-coupling dyeing method thereof of the present invention, the step 2):

[0040] The aromatic aminated cellulose obtained in step 1) is placed in an aqueous solution containing hydrochloric acid, and then an aqueous NaNO2 solution is added (dropwise for about 5±1 min), and the reaction is stirred at room temperature for 10 to 30 min; the molar ratio of HCl to NaNO2 is 1:(1.01±0.01), and the amount ratio of NaNO2 to the ester-type aromatic amination reagent in step 1) is: 0.012 to 0.02 mol NaNO2 / 0.3 to 0.5 g ester-type aromatic amination reagent; that is, about 0.012 to 0.02 mol NaNO2 / 0.0011 to 0.0018 mol ester-type aromatic amination reagent;

[0041] The aromatic aminated cellulose after the reaction is taken out, washed with water (until there are no solid particles on the fiber surface), and dried (dried with cold air) to obtain diazotized cellulose for later use.

[0042] As a further improvement of the aromatic primary amination modification and diazotization-coupling dyeing method of the cellulose fiber of the present invention, the step 3):

[0043] The buffer solution is a sodium carbonate-sodium bicarbonate buffer solution with a pH of 9, and the volume ratio of the buffer solution to water is 1:3.5-4.5.

[0044] As a further improvement of the aromatic primary amination modification and diazotization-coupling dyeing method of the cellulose fiber of the present invention, the step 3):

[0045] Under continuous shaking, the diazotized cellulose obtained in step 2) is placed in the coupling component solution and soaked at room temperature for 0.5 to 1 hour, thereby dyeing to obtain coupled dyed fibers;

[0046] 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.

[0047] Note: The above water washing is performed alternately with hot water washing at 40±10℃ and cold water washing at 5-10℃.

[0048] As a further improvement of the aromatic primary amination modification of cellulose fibers and the diazotization-coupling dyeing method thereof of the present invention, the cellulose fibers are any of the following:

[0049] Natural fibers, man-made fibers, and blends of natural and man-made fibers.

[0050] The natural fiber is any of the following: cotton, linen, bamboo fiber;

[0051] The artificial fiber is viscose fiber.

[0052] Cellulose macromolecules are composed of β-D-glucose residues linked to each other by 1,4-glycosidic bonds. There are a large number of hydroxyl groups on the two terminal glucose residues of the cellulose macromolecule. By modifying the cellulose fibers with ester-type aromatic primary amination reagents, a sufficient amount of aromatic primary amine groups can be introduced into the cellulose fibers. The aromatic primary aminated cellulose can be prepared into diazotized cellulose through a diazotization reaction, and then dyed with a coupling component, thereby realizing diazotization-coupling dyeing of the aromatic primary aminated modified cellulose fibers.

[0053] The diazotization-coupling dyeing mechanism of cellulose fibers modified by aromatic primary amination is as follows:

[0054]

[0055] In the present invention, the fabrics woven from the natural fibers of cotton, hemp, bamboo fiber and artificial fiber viscose fiber, as well as the blended fabrics made from these fibers, can be purchased on the market.

[0056] In the present invention, the substances used, such as concentrated hydrochloric acid, sodium nitrite, urea, sodium hydroxide, sodium carbonate and sodium bicarbonate, are all commonly known chemical products and can be purchased commercially.

[0057] For the cellulose fibers obtained by the dyeing method provided in the present invention, the color fastness to dry and wet rubbing and the color fastness to washing are tested according to the national standards commonly used in this field.

[0058] In the present invention:

[0059] Cellulose fibers are modified with ester-type aromatic amination reagents for aromatic amination, and then dyed quickly at room temperature through a further diazotization coupling reaction; whereas existing technologies for reactive dyeing require longer reaction times.

[0060] The coupled dye can be covalently bonded to the diazotized cellulose under alkaline conditions at room temperature; while the existing technology requires covalent bonding at 0-5°C and alkaline conditions.

[0061] The present invention has the following beneficial effects:

[0062] The present invention successfully subjects cellulose fibers to primary aromatic amination, followed by diazotization, and then further coupling dyeing with a coupling component. This effectively combines the synthesis process of an azo dye with the dyeing process of cellulose fibers, achieving a novel reactive dyeing method. This significantly reduces energy consumption throughout the dyeing process, avoids the discharge of colored wastewater during the dyeing process, and realizes an environmentally friendly green dyeing method. Furthermore, the color fastness to rubbing and washing of the dyed cellulose fibers is also improved. Furthermore, in the present invention, the azo dye (formed by the reaction of the coupling component with the aromatic diazonium salt in the diazotized cellulose structure in step 3) is connected to the fibers via an ether bond, resulting in excellent alkali resistance and stability, thereby improving the product's application performance and providing a novel dyeing method for cellulose fibers.

[0063] The main technical advantage of the present invention over "Aromatic Amination Modification and Dyeing Method for Cellulose Fibers" (CN 117306277A) is that the fiber and the pigment are connected through an ether bond, thereby improving the alkali resistance stability.

[0064] The dyeing method provided by the present invention can be used to dye cellulose fiber fabrics such as cotton, linen, bamboo, and viscose fibers. The dyeing process has low energy consumption and short dyeing time. The dyed fabrics have bright colors, high color fastness to wet treatment, and strong practicality. The dyed fabrics also have high alkali resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0066] Figure 1 The meta-ester modified yellow cellulose fabric (1-(4-sulfonic acid phenyl)-3-carboxyl-5-pyrazolone) obtained in Example 1 and its K / S curve;

[0067] Figure 2 The para-ester modified yellow cellulose fabric (1-(4-sulfonic acid phenyl)-3-carboxyl-5-pyrazolone) obtained in Example 2 and its K / S curve;

[0068] Figure 3 The meta-ester modified red cellulose fabric (acetyl H acid) obtained in Example 3 and its K / S curve;

[0069] Figure 4 The para-ester modified blue cellulose fabric (H acid couple) obtained in Example 4 and its K / S curve;

[0070] Figure 5 The isatoic anhydride-modified yellow cellulose fabric (1-(4-sulfonate phenyl)-3-carboxyl-5-pyrazolone) obtained in Comparative Example 1 and its K / S curve;

[0071] Figure 6 The K / S curves and fabric samples of the yellow cellulose fabrics of Example 1, Example 2 and Comparative Example 1 before and after alkali washing are shown;

[0072] Figure 7 The yellow cellulose fabric modified with sulfonated para-ester obtained in Comparative Example 2 and its K / S curve are shown. DETAILED DESCRIPTION

[0073] The present invention is further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto:

[0074] The room temperature in the present invention refers to 20-30° C. (preferably 25° C.) The concentration of concentrated hydrochloric acid is 36% to 38%.

[0075] Meta-ester:

[0076] Para esters are:

[0077] The pH 9 buffer solution is a conventional pH 9 sodium carbonate-sodium bicarbonate buffer solution.

[0078] Example 1: A method for aromatic amination modification of cellulose fibers and diazotization-coupling dyeing thereof:

[0079] The cellulose fiber is 10 g of cotton fabric, the dyeing bath ratio is 1:20, and the following steps are carried out in sequence:

[0080] 1) Aromatic amination modification of cellulose fibers:

[0081] Aromatic amination modification was achieved by immersing 10 g of cotton fabric in 200 mL of an aqueous solution containing 0.05 g of a meta-ester, adding 1 g of Na₂CO₃, and reacting at 50°C for 0.5 h. The fabric was then washed in hot water at 40 ± 10°C for 0.5 h, rinsed with clean water at 5–10°C, and air-dried to constant weight to obtain the aromatic amination-modified cotton fabric.

[0082] That is, the amount of the meta-ester used was 0.5% owf relative to the cotton fabric.

[0083] Note: The purpose of washing with hot water and 5-10℃ water is to remove unreacted ester-type aromatic amination reagent and its hydrolysis products on the cellulose fibers.

[0084] 2) Diazotization of aromatic amination cotton fabrics:

[0085] Mix concentrated hydrochloric acid containing 0.002 mol of HCl with 50 mL of water to obtain a hydrochloric acid solution;

[0086] Prepare an aqueous solution of sodium nitrite by mixing 0.00201 mol of sodium nitrite with 5 mL of water;

[0087] The aromatic aminated cotton fabric obtained in step 1) is placed in the above-mentioned hydrochloric acid solution, and then an aqueous solution of sodium nitrite is slowly added dropwise (for about 5 minutes). After stirring and reacting at room temperature for 10 minutes, excess nitrous acid is removed with urea; then the fabric is taken out and washed with water (when there are no solid particles on the surface of the cotton fabric, the washing is completed), and then blown dry (until it is substantially free of water, that is, the moisture content is ≤2%) to obtain a diazotized cotton fabric.

[0088] Using urea to remove excess nitrous acid is a conventional technique, for example, see CN 117306277 A.

[0089] 3) Coupling dyeing of diazotized cotton fabrics:

[0090] 1-(4-sulfonic acid phenyl)-3-carboxyl-5-pyrazolone was selected as the yellow coupling component, and its structural formula is:

[0091]

[0092] 1-(4-sulfonic acid phenyl)-3-carboxy-5-pyrazolone, a buffer solution with a pH of 9, and water are mixed to form a coupling component solution, wherein the concentration of 1-(2,5-dichloro-4-sulfonic acid phenyl)-3-methyl-5-pyrazolone in the coupling component solution is 2 g / L, and the buffer solution:water ratio is 1:4.

[0093] Under constant shaking, the diazotized cotton fabric obtained in step 2) was placed in 200 mL of the coupling component solution and soaked at room temperature for 30 min to achieve dyeing. The fabric was then washed alternately with hot water at 40±10°C and cold water at 5-10°C, and finally dried to constant weight to obtain dyed cotton fabric A1.

[0094] Note: The purpose of alternating hot water washing and cold water washing is to remove various impurities adsorbed on the fabric. The washing is terminated when the eluent has no color.

[0095] Experiment 1: The dyed cotton fabric A1 obtained in Example 1 was tested according to the "Color fastness to washing GB / T 3921-2008" and "Color fastness to rubbing GB / T 3920-2008":

[0096] K / S curve and fabric sample diagram Figure 1 As shown, the maximum K / S value for dyeing is 10.63. The dyed fabric exhibits color fastness to dry rubbing of level 5, color fastness to wet rubbing of level 4-5, and color fastness to soaping of level 4-5. The relative color fastness reaches 96.9%, demonstrating that the dyed fabric using this method exhibits excellent color fastness. The resulting dyed cotton fabric A1 is bright yellow.

[0097] Example 2: A method for aromatic primary amination modification and diazotization-coupling dyeing of cellulose fibers, which differs from Example 1 only in that the meta-ester is replaced by the para-ester;

[0098] Specifically, perform the following steps in sequence:

[0099] 1) Aromatic amination modification of cellulose fibers:

[0100] The meta-ester in step 1) of Example 1 was replaced with the para-ester, and the amount used remained unchanged (ie, 0.5% owf). The rest was the same as step 1) of Example 1.

[0101] 2) Diazotization of aromatic amination cotton fabrics:

[0102] The aromatic aminated cotton fabric obtained in step 1) is diazotized according to step 2) of Example 1) to obtain diazotized cotton fabric.

[0103] 3) Coupling dyeing of diazotized cotton fabrics:

[0104] The diazotized cotton fabric obtained in step 2) was subjected to coupling dyeing according to step 3) of Example 1) to obtain dyed cotton fabric A2.

[0105] Experiment 2: The dyed cotton fabric A2 obtained in Example 2 was tested according to the method described in Experiment 1:

[0106] K / S curve and fabric sample diagram Figure 2 As shown, the maximum K / S value of the dyeing was 9.87. The dyed fabric had a color fastness to dry rubbing of 4-5, a color fastness to wet rubbing of 4-5, and a color fastness to soaping of 5. The relative color fastness reached 96.1%, demonstrating that the dyeing method exhibits excellent color fastness. The resulting dyed cotton fabric A2 was a bright yellow.

[0107] Example 3: A method for aromatic amination modification of cellulose fibers and diazotization-coupling dyeing thereof:

[0108] The cellulose fiber is 10 g of linen fabric, the dyeing bath ratio is 1:20, and the following steps are carried out in sequence:

[0109] 1) Aromatic amination modification of cellulose fibers:

[0110] A 10-gram hemp fabric was immersed in a 200-mL aqueous solution containing 0.50 g (i.e., 5% owf) of a meta-ester. 2 g of Na₂CO₃ was added and the mixture was reacted at 70°C for 2 h to complete the aromatic primary amination modification. The fabric was then washed in hot water at 40±10°C for 0.5 h, rinsed with clean water at 5-10°C, and air-dried to constant weight to obtain the aromatic primary amination hemp fabric.

[0111] 2) Diazotization of aromatic amination linen fabric:

[0112] Mix concentrated hydrochloric acid containing 0.02 mol of HCl with 50 mL of water to obtain a hydrochloric acid solution;

[0113] Prepare an aqueous solution of sodium nitrite by mixing 0.0201 mol of sodium nitrite with 5 mL of water;

[0114] The aromatic primary aminated linen fabric obtained in step 1) is placed in the above-mentioned hydrochloric acid solution, and then an aqueous solution of sodium nitrite is slowly added dropwise (about 5 minutes). After stirring and reacting at room temperature for 30 minutes, excess nitrous acid is removed with urea; then the fabric is taken out, washed with water, and then blown dry to obtain a diazotized linen fabric.

[0115] 3) Coupling dyeing of diazotized linen fabric:

[0116] Acetyl H acid was selected as the red coupling component, and its structural formula is:

[0117]

[0118] A coupling component solution is formed by mixing acetyl H acid, a buffer solution with a pH of 9, and water. In the coupling component solution, the concentration of acetyl H acid is 2 g / L, and the ratio of buffer solution to water is 1:4.

[0119] Under constant shaking, the diazotized linen fabric obtained in step 2) was placed in 200 mL of the coupling component solution and soaked at room temperature for 1 h to achieve dyeing. The fabric was then washed alternately with hot water at 40±10°C and cold water at 5-10°C, and finally dried to constant weight to obtain dyed linen fabric B1.

[0120] Experiment 3: The dyed linen fabric B1 obtained in Example 3 was tested according to the method described in Experiment 1:

[0121] K / S curve and fabric sample diagram Figure 3 As shown, the maximum K / S value for dyeing is 20.78. The dyed fabric has a color fastness of 4-5 to dry rubbing, 4-5 to wet rubbing, and 4-5 to soaping. The relative color fastness reaches 95.4%, demonstrating that the dyed fabric using this method exhibits excellent color fastness. The resulting dyed linen fabric B1 is a deep red.

[0122] Example 4: A method for aromatic amination modification of cellulose fibers and diazotization-coupling dyeing thereof:

[0123] The cellulose fiber is 10 g of viscose fiber fabric, the dyeing bath ratio is 1:20, and the following steps are carried out in sequence:

[0124] 1) Aromatic amination modification of cellulose fibers:

[0125] A 10-gram viscose fabric was immersed in a 200-mL aqueous solution containing 0.30 g (i.e., 3% owf) of a para-ester. 2 g of NaCO₃ was added and the reaction was carried out at 60°C for 1 hour to complete the aromatic amination modification. The fabric was then washed in hot water at 40±10°C for 0.5 hour, rinsed with clean water at 5-10°C, and air-dried to constant weight to obtain the aromatic amination viscose fabric.

[0126] 2) Diazotization of aromatic amination viscose fiber fabrics:

[0127] Mix concentrated hydrochloric acid containing 0.012 mol of HCl with 50 mL of water to obtain a hydrochloric acid solution;

[0128] Prepare an aqueous solution of sodium nitrite by mixing 0.0121 mol of sodium nitrite with 5 mL of water;

[0129] The aromatic aminated viscose fiber fabric obtained in step 1) is placed in the above-mentioned hydrochloric acid solution, and then an aqueous solution of sodium nitrite is slowly added dropwise (about 5 minutes). After stirring and reacting at room temperature for 20 minutes, excess nitrous acid is removed with urea; then the fabric is taken out, washed with water, and then blown dry to obtain a diazotized viscose fiber fabric.

[0130] 3) Coupling dyeing of diazotized viscose fiber fabrics:

[0131] Select H acid couple as the blue coupling component, and its structural formula is:

[0132]

[0133] The H acid-acid couple, a buffer solution with a pH of 9, and water are mixed to form a coupling component solution, wherein the concentration of the H acid-acid couple is 2 g / L, and the buffer solution:water ratio is 1:4.

[0134] Under constant shaking, the diazotized viscose fiber fabric obtained in step 2) was placed in 200 mL of the coupling component solution and soaked at room temperature for 1 h to achieve dyeing. The fabric was then alternately washed with hot water at 40±10°C and cold water at 5-10°C, and finally dried to constant weight to obtain dyed viscose fiber fabric C1.

[0135] Experiment 4: The dyed viscose fiber fabric C1 obtained in Example 4 was tested according to the method described in Experiment 1:

[0136] K / S curve and fabric sample diagram Figure 4As shown, the maximum K / S value for dyeing is 16.42. The dyed fabric has a color fastness of 5 to dry rubbing, 4-5 to wet rubbing, and 4-5 to soaping. The relative color fastness reaches 96.5%, demonstrating that the dyed fabric using this method exhibits excellent color fastness. The resulting dyed viscose fabric C1 is dark blue.

[0137] Comparative Example 1: Using the method mentioned in patent CN 117306277 A, cellulose fibers were subjected to aromatic primary amination modification and diazotization-coupling dyeing using isatoic anhydride:

[0138] The cellulose fiber is 10 g of cotton fabric, the dyeing bath ratio is 1:20, and the following steps are carried out in sequence:

[0139] 1) Cellulose fiber modification (using isatoic anhydride to modify cotton fabric):

[0140] 10 g of cotton fabric (the same original cotton fabric used in Example 1) was immersed in 500 mL of a solution of 0.3 g (0.0018 mol) of isatoic anhydride in N,N-dimethylformamide (DMF) and reacted at 100°C for 6 h to achieve aromatic primary amination modification. The fabric was then washed in hot water at 60±10°C for 0.5 h, followed by a cold wash at 5-10°C to obtain isatoic anhydride-modified cotton fabric.

[0141] 2) Diazotization of isatoic anhydride modified cotton fabric:

[0142] Mix concentrated hydrochloric acid containing 0.01 mol of HCl with 15 g of water to obtain a hydrochloric acid solution;

[0143] Prepare an aqueous solution of sodium nitrite by mixing 0.0101 mol of sodium nitrite with 1 g of water;

[0144] The isatoic anhydride-modified cotton fabric obtained in step 1) is placed in the above-mentioned hydrochloric acid solution, and then an aqueous solution of sodium nitrite is slowly added dropwise (about 5 minutes). After stirring and reacting at room temperature for 10 minutes, excess nitrous acid is removed with urea; then the fabric is taken out, washed with water, and then blown dry to obtain a diazotized cotton fabric.

[0145] Note: The above steps 1) and 2) are completely the same as steps 1) and 2) of patent CN 117306277 A.

[0146] 3) Coupled dyeing:

[0147] 1-(4-sulfonic acid phenyl)-3-carboxyl-5-pyrazolone was selected as the yellow coupling component, and its structural formula is:

[0148]

[0149] 1-(4-sulfonic acid phenyl)-3-carboxy-5-pyrazolone, sodium hydroxide, sodium carbonate and water are mixed to form a coupling component solution, wherein the concentration of 1-(4-sulfonic acid phenyl)-3-carboxy-5-pyrazolone is 2 g / L, the concentration of sodium hydroxide is 0.2 g / L, and the concentration of sodium carbonate is 5 g / L.

[0150] Under constant shaking, the diazotized cotton fabric obtained in step 2) is placed in 200 mL of the coupling component solution, soaked and reacted at room temperature for 10 min to achieve dyeing, then alternately washed with hot water at 60±10°C and cold water at 5-10°C, and finally dried to constant weight to obtain dyed cotton fabric a1.

[0151] The K / S curve of the cotton fabric treated by the method described in Comparative Example 1 is as follows: Figure 5 The maximum K / S value of dyeing is 6.33. According to the method described in Experiment 1, the color fastness of the dyed fabric to dry friction is 4-5, the color fastness to wet friction is 4-5, the color fastness to soaping is 4-5, and the relative color fastness rate reaches 96.2%.

[0152] By comparing Example 1 and Comparative Example 1, it can be found that, when the coupling components remain unchanged, the amount of aromatic amination reagent used in the method of the present invention is less, and the color depth of the dyed fabric obtained is higher under the condition of shorter aromatic amination modification time, and the color fastness of the dyed fabric can reach the same or even higher level.

[0153] Comparative Example 2: The meta-ester in step 1) of Example 1 was replaced with a sulfonated para-ester. The structural formula of the sulfonated para-ester is as follows: The remaining steps are the same as those in Example 1 to obtain dyed cotton fabric A3.

[0154] The test was carried out according to the method described in Experiment 1. The results were as follows: K / S curve and fabric sample diagram are shown in Figure 1. Figure 7 As shown, the maximum K / S value of dyeing is 2.70. The color fastness of the dyed fabric to dry friction is level 4-5, the color fastness to wet friction is level 4-5, the color fastness to soaping is level 4-5, and the relative color fixation rate reaches 97.4%.

[0155] This indicates that, despite the structure of the aromatic primary aminated modifier used in Comparative Example 2, the resulting dyed cotton fabric A3 exhibits a lighter color depth, i.e., a lower K / S value, than A1 and A2. This may be due to the sulfonic acid groups on the para-ester sulfonate increasing its solubility in water, resulting in a weaker attraction to the fiber and a lower modification rate.

[0156] The comparison of the above cases is shown in Table 1 below.

[0157] Table 1

[0158]

[0159]

[0160] Experiment 5: The dyed cotton fabrics A1 and A2 obtained in Examples 1 and 2 and the dyed cotton fabric a1 obtained in Comparative Example 1 were subjected to an alkali resistance test using the following method:

[0161] 10 g of each dyed cotton fabric was placed in 200 mL of a sodium hydroxide aqueous solution with a concentration of 5 g / L and boiled for 30 min. The fabric was then washed alternately with hot water at 60 ± 10°C and cold water at 5-10°C, and finally air-dried to constant weight.

[0162] Note: The above-mentioned alternating hot water washing and cold water washing is to remove the sodium hydroxide and various impurities adsorbed on the fabric, and the washing is terminated until the eluent has no color.

[0163] K / S curve and fabric sample before and after alkali washing are as follows Figure 6 The fading rates are shown in Table 2. The results show that the fading rate of a1 is much greater than that of A1 and A2. This indicates that the dyed cotton fabric obtained by the present invention possesses superior alkali resistance compared to the dyed cotton fabric obtained by the isatoic anhydride modification method. This is attributed to the fact that during isatoic anhydride modification, the azo pigment and cellulose fiber are bonded via ester bonds, while in the present invention, the azo pigment and cellulose fiber are bonded via ether bonds, which have superior alkali resistance stability compared to ester bonds.

[0164] Table 2

[0165] sample K / S before alkali washing K / S after alkali washing Fading rate / % A1 10.63 8.41 20.9 A2 9.87 7.93 19.6 a1 6.33 1.69 73.3

[0166] Finally, it should be noted that the above examples are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples and is subject to numerous variations. All variations that can be directly derived or conceived by a person of ordinary skill in the art from the disclosure of the present invention are considered to be within the scope of protection of the present invention.

Claims

1. Aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing method thereof, characterized in that The following steps are involved: 1) Modify cellulose fiber with an ester-type aromatic amination reagent to obtain aromatic amination cellulose; 2) Diazotization of aromatic aminated cellulose: Diazotizing the aromatic primary aminated cellulose obtained in step 1) to obtain diazotized cellulose; 3) Coupled dyeing of diazotized cellulose; The diazotized cellulose obtained in step 2) is added to the coupling component solution to carry out a coupling color development reaction, thereby generating a coupled color development fiber.

2. The method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof according to claim 1, characterized in that: 1) Ester-type aromatic amination reagent modified cellulose fiber: In water containing sodium carbonate, cellulose fibers are subjected to an aromatic amination modification reaction using an ester-type aromatic amination reagent, wherein the amount of the ester-type aromatic amination reagent is 0.5-5% of the mass of the cellulose fibers, the ratio of sodium carbonate to water is 5-10 g / L, the reaction temperature is 60±10° C., and the reaction time is 0.5-2 h; The cellulose fibers after the reaction are washed and named as aromatic primary aminated cellulose; 2) Diazotization of aromatic aminated cellulose: Diazotizing the aromatic primary aminated cellulose obtained in step 1) to obtain diazotized cellulose; 3) Coupled dyeing of diazotized cellulose; The coupling components are placed in water, and then a buffer solution with a pH of 9±0.2 is added to form a coupling component solution; In the coupling component solution, the concentration of the coupling component is 2±0.2 g / L; The diazotized cellulose obtained in step 2) is added to the coupling component solution to carry out a coupling color reaction, thereby generating a coupled color fiber; the coupling color bath ratio is 1:20-100, and the color reaction is 0.5-1h.

3. The method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof according to claim 2, characterized in that: The coupling components are yellow coupling components, red coupling components, and blue coupling components; The yellow coupling component is 1-(4-sulfonate phenyl)-3-carboxy-5-pyrazolone; The red coupling component is acetyl H acid; The blue coupling component is an H acid couple.

4. The method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof according to claim 3, characterized in that Step 1): The ester-type primary aromatic amination reagent is any one of the following: meta-ester and para-ester.

5. The method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof according to claim 4, characterized in that Step 2): The aromatic aminated modified cellulose fiber obtained in step 1) is placed in an aqueous solution containing hydrochloric acid, and then an aqueous solution of NaNO2 is added, and the mixture is stirred and reacted at room temperature for 10 to 30 minutes; the molar ratio of HCl to NaNO2 is 1: (1.01 ± 0.01), The usage ratio of NaNO2 to the ester type aromatic primary amination reagent in step 1) is: 0.012-0.02 mol NaNO2 / 0.3-0.5 g ester-type aromatic amination reagent; The aromatic aminated modified cellulose fibers after the reaction are taken out, washed with water, and dried to obtain diazotized cellulose.

6. The method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof according to claim 5, characterized in that Step 3): The buffer solution is a sodium carbonate-sodium bicarbonate buffer solution with a pH of 9, and the volume ratio of the buffer solution to water is 1:3.5-4.

5.

7. The method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof according to claim 6, characterized in that Step 3): Under continuous shaking, the diazotized cellulose obtained in step 2) is placed in the coupling component solution and soaked at room temperature for 0.5 to 1 hour, thereby dyeing to obtain coupled dyed fibers; Then, the coupled dyed fibers are washed and dried to obtain dyed cellulose fibers.

8. The method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof according to claim 7, characterized in that The cellulose fiber is any one of the following: Natural fibers, man-made fibers, and blends of natural and man-made fibers.

9. The method for aromatic primary amination modification of cellulose fibers and diazotization-coupling dyeing thereof according to claim 8, characterized in that: The natural fiber is any of the following: cotton, linen, bamboo fiber; The artificial fiber is viscose fiber.

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