Room temperature salt-free rapid reactive dyeing and recycling method for cellulose fibers

Abstract

The present invention belongs to the field of dyeing and finishing and corresponding recycling, and specifically relates to a room temperature salt-free rapid reactive dyeing and recycling method applicable to cellulose fibers, which has the advantages of reducing environmental pollution and being green and environmentally friendly. The present invention discloses a room temperature salt-free rapid reactive dyeing and recycling method applicable to cellulose fibers, comprising the following steps: modifying cellulose fibers with isatoic anhydride derivatives; diazotizing the obtained isatoic anhydride modified cellulose with a diazotizing agent at room temperature to obtain diazotized cellulose; mixing a coupling component and water to form a coupling component solution, mixing the diazotized cellulose fibers with the coupling component solution, and then performing a coupling color development reaction at room temperature, and then soaping to obtain soaped coupled dyed fibers. The present invention can also use an alkali boiling method to remove dyes from cellulose fibers to achieve recycling and reuse of cellulose fibers.

Description

Technical Field

[0001] The invention belongs to the field of dyeing and finishing and corresponding recycling, and specifically relates to a room temperature salt-free rapid reactive dyeing and recycling method suitable for cellulose fibers, which has the advantages of reducing environmental pollution and being environmentally friendly. Background Art

[0002] Cellulose fiber is one of the important raw materials in the textile industry. Cotton fiber, linen fiber, bamboo fiber, and viscose fiber contain a large number of hydroxyl groups in their molecular structure and can undergo substitution reactions with electrophilic dyes to achieve reactive dyeing of fabrics.

[0003] Reactive dyes have excellent electrophilic active groups and are widely used in cellulose fiber dyeing because of their advantages such as complete color spectrum, high wet fastness, and ease of use. However, the temperature is high and the energy consumption is large during dyeing, and in order to obtain a high dye exhaustion rate, a large amount of electrolyte (such as sodium chloride) is required to promote dyeing. In addition, when dyeing cellulose fiber fabrics, it is usually necessary to add alkaline substances (such as sodium carbonate) for high-temperature fixation treatment to promote the formation of covalent bonds between the dye and the fiber and improve color fastness. However, the active groups of reactive dyes also have problems such as easy hydrolysis and poor storage stability. The fixation rate is only 50%-80%. A large amount of hydrolyzed dyes enter the dyeing wastewater, so a large amount of salt-containing colored wastewater will be produced, which increases the difficulty and cost of wastewater treatment and is not conducive to environmental protection.

[0004] The covalent bonds formed between reactive dyes and cellulose fibers are mostly ester or ether bonds, which have a certain degree of alkali stability. Therefore, it is difficult to achieve good decolorization in alkaline solutions, making it difficult to recycle and reuse dyed cellulose fibers, which is not conducive to the recycling of cellulose fibers in the textile field.

[0005] The invention of CN 117306277 A "Aromatic amination modification and dyeing method for cellulose fibers" reports a diazotization-coupling dyeing method for cellulose fibers modified with isatoic anhydride. However, this method still has the disadvantages of high isatoic anhydride modification temperature, low modification rate (related to K / S), and long modification time. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a room temperature salt-free rapid reactive dyeing and recycling method suitable for cellulose fibers, that is, the present invention provides a diazotization-coupling dyeing method for cellulose fibers modified with isocyanate anhydride, and uses an alkali solution boiling method to remove the dye on the cellulose fibers, thereby realizing the recycling and reuse of the cellulose fibers.

[0007] In order to solve the above technical problems, the present invention provides a room temperature salt-free rapid reactive dyeing and recycling method applicable to cellulose fibers, comprising the following steps:

[0008] 1) Cellulose fibers modified with isatoic anhydride derivatives:

[0009] Add cellulose fiber, isocyanate and its derivatives (i.e., isocyanate or isocyanate derivatives) and a catalyst to a solvent to form a modification system, and then add a base to adjust and maintain the pH of the modification system at 7.5 to 9.0, and perform a modification reaction at a reaction temperature of 20 to 40° C. for a reaction time of 0.5 to 5 h (preferably 30° C. for 2 h);

[0010] The amount of isatoic anhydride and its derivatives is 0.01% to 10% (preferably 2.5% to 3.5%) of the mass of the cellulose fiber;

[0011] The catalyst is 4-dimethylaminopyridine (DMAP); the dosage of 4-dimethylaminopyridine (DMAP) is 1% to 10% of the mass of isatoic anhydride and its derivatives;

[0012] After the reaction is completed, post-treatment is performed to obtain isatoic anhydride-modified cellulose;

[0013] 2) Diazotization of isatoic anhydride modified cellulose:

[0014] At room temperature, diazotizing the isatoic anhydride-modified cellulose obtained in step 1) using a diazotizing agent to obtain diazotized cellulose;

[0015] 3) Coupling dyeing of diazotized cellulose:

[0016] Mixing the coupling component and water to form a coupling component solution, wherein the concentration of the coupling component in the coupling component solution is 2±0.2 g / L;

[0017] Under constant shaking, the diazotized cellulose fiber obtained in step 2) is mixed with the coupling component solution at a coupling dyeing bath ratio of 1 g: 5 to 100 mL (i.e., the coupling dyeing bath ratio is 1: 5 to 100, preferably 1: 15 to 25, and more preferably 1: 20), and a coupling color reaction is performed at room temperature, and the pH is controlled to be 4 to 10 during the reaction, thereby generating coupled dyed fibers; and then soaping (conventional soaping) is performed to obtain soaped coupled dyed fibers;

[0018] Note: As a matter of common sense, pH adjustment can be achieved with conventional sodium carbonate and dilute hydrochloric acid;

[0019] Specifically: the coupling color reaction is divided into two situations. The first is the ortho-coupling of phenolic hydroxyl, which requires alkaline conditions, pH 7-10; the second is the ortho-coupling of amino group, which requires acidic conditions, pH 4-7.

[0020] As an improvement of the room temperature salt-free rapid reactive dyeing and recycling method applicable to cellulose fibers of the present invention, the method further includes the following step 4):

[0021] 4) The dye on the soap-washed coupled-dyed fiber obtained in step 3) is removed by boiling with alkali solution to achieve the recycling and reuse of the cellulose fiber.

[0022] As a further improvement of the room temperature salt-free rapid reactive dyeing and recycling method suitable for cellulose fibers of the present invention, in step 1): the isatoic anhydride derivatives include isatoic anhydride, 4-chloroisatoic anhydride, 4-bromoisatoic anhydride, 4-nitroisatoic anhydride, 3-chloroisatoic anhydride, 6-methylisatoic anhydride, 4-methylisatoic anhydride, 5-fluoroisatoic anhydride, 5-nitroisatoic anhydride, 5-bromoisatoic anhydride, 5-chloroisatoic anhydride, and 4,5-dimethoxyisatoic anhydride.

[0023] The details are shown in Table 1 below:

[0024] Table 1

[0025]

[0026]

[0027] As a further improvement of the room temperature salt-free rapid reactive dyeing and recycling method applicable to cellulose fibers of the present invention, in step 1):

[0028] The solvent is composed of a co-solvent and water, wherein the volume ratio of the co-solvent to water is 2% to 60% (preferably 4 to 5%); the co-solvent is N,N-dimethylformamide (DMF), DMSO or dioxane;

[0029] The base is sodium carbonate or potassium acetate;

[0030] The usage ratio of cellulose fiber to solvent is 1g:5-100ml (preferably 1g:40-60ml).

[0031] As a further improvement of the room temperature salt-free rapid reactive dyeing and recycling method suitable for cellulose fibers of the present invention, the post-treatment in step 1) is: first washing in hot water at 60±10°C (the washing time is about 10 to 30 minutes, so as to remove the isatoic anhydride derivatives and their hydrolysis products attached to the surface of the cellulose fibers), and then washing with cold water at 5 to 10°C; obtaining isatoic anhydride modified cellulose.

[0032] As a further improvement of the room temperature salt-free rapid reactive dyeing and recycling method applicable to cellulose fibers of the present invention, step 2): the diazotization reagent is composed of sodium nitrite and acid;

[0033] The isatoic anhydride modified cellulose obtained in step 1) is placed in an acid aqueous solution, 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 the acid to NaNO2 is 1:(1.01±0.01), and (0.002±0.0001) mol of acid is added for every 10 g of cellulose fiber;

[0034] The cellulose after the reaction is taken out, washed with water (washed with cold water at 5-10°C) and then blown dry to obtain diazotized cellulose.

[0035] Generally speaking, 0.002 mol of acid is mixed with 14-16 mL of water to make an acid solution; 0.002 mol of sodium nitrite is mixed with 0.8-1.2 mL of water to make a NaNO2 aqueous solution;

[0036] As a further improvement of the room temperature salt-free rapid reactive dyeing and recycling method applicable to cellulose fibers of the present invention:

[0037] In step 2): the acid is hydrochloric acid, sulfuric acid, or glacial acetic acid;

[0038] In the step 3), the coupling component is an aromatic amine compound, a phenolic compound, an active methylene compound, and a monoazo dye containing a coupling site;

[0039] Specifically:

[0040] Aromatic amine compounds (i.e., compounds containing both phenol and aromatic amine structures) are H acids, J acids, and γ acids;

[0041] The phenolic compounds are N-acetyl H acid, 2-naphthol, chromotropic acid, p-phenylphenol, G salt, Schaffer acid, R acid, N-acetyl gamma acid, NW acid, FC acid, 2,3-acid, salicylic acid, N-acetyl J acid;

[0042] Active methylene compounds are pyrazolone, pyridone and their derivatives;

[0043] Pyrazolone derivatives include 1-phenyl-3-methyl-5-pyrazolone, 1-(4-sulfonate phenyl)-3-methyl-5-pyrazolone, 1-(2,5-dichloro-4-sulfonate phenyl)-3-methyl-5-pyrazolone, 3-carboxy-1-(4-sulfonate phenyl)-5-pyrazolone;

[0044] Pyridone derivatives include 3-cyano-1,4-dimethyl-6-hydroxy-2-pyridone, N-ethyl-3-cyano-4-methyl-6-hydroxy-2-pyridone;

[0045] The monoazo dyes containing coupling sites include H acid-acid coupling monocoupling compounds, H acid-base coupling monocoupling compounds, and color-changing acid-base coupling monocoupling compounds.

[0046] In the present invention, the optional coupling components and the final cellulose fiber color (isatoic anhydride is the amination agent) are specifically shown in Table 3 below.

[0047] As a further improved step 3) of the room temperature salt-free rapid reactive dyeing and recycling method applicable to cellulose fibers of the present invention, the method comprises:

[0048] Under constant shaking, the diazotized cellulose obtained in step 2) is placed in the coupling component solution and soaked at room temperature for 10 to 20 minutes to achieve coupling color development and generate coupled dyed fibers;

[0049] Then, the coupled dyed fiber is subjected to conventional soap washing to remove floating color (remove various substances adsorbed on the cellulose fiber), and dried to obtain dyed cellulose fiber;

[0050] The conventional soap washing to remove floating color is as follows: 1g of cloth, 0.25g of soap flakes, washing at 50°C for 45min.

[0051] As a further improvement of the room temperature salt-free rapid reactive dyeing and recycling method suitable for cellulose fibers of the present invention, step 4) is: prepare 10-70 g / L (preferably 35-45 g / L) NaOH solution as alkali solution, put the soaped coupled dyed fiber obtained in step 3) into the alkali solution at a bath ratio of 1:30, and decolorize at 95-100°C for 20-40 minutes.

[0052] Description: After being treated by the above-mentioned high-temperature hydrolysis decolorization method, decolorized cellulose fibers with higher whiteness can be obtained, which is conducive to the recycling and reuse of cellulose fibers.

[0053] As a further improvement of the room temperature salt-free rapid reactive dyeing and recycling method applicable to cellulose fibers of the present invention, the cellulose fibers are any of the following:

[0054] Natural fibers, artificial fibers, natural fibers and artificial fiber bulk fibers and fabrics and blended fabrics made therefrom.

[0055] The natural fiber is any of the following: cotton, linen, bamboo fiber;

[0056] The man-made fiber is viscose fiber.

[0057] Description, in the present invention:

[0058] Cellulose fibers are modified with isatoic anhydride derivatives, and the hydroxyl groups on the cellulose fibers react with isatoic anhydride derivatives, thereby introducing aromatic primary amine structures on the cellulose fibers to obtain isatoic anhydride-modified cellulose; the reaction temperature of the "modification" in step 1) of the present invention is 20-40°C, without the need for high temperature, and the modification rate is significantly improved (as reflected by the final coupled color-developing fabric K / S value). Subsequently, the isatoic anhydride-modified cellulose is directly reacted with the coupling component after diazotization to generate a colored substance containing an azo structure, thereby achieving room temperature salt-free rapid reactive dyeing of the cellulose fibers. The alkali solution boiling method is further used to remove the dye on the cellulose fibers to achieve the recycling and reuse of the cellulose fibers.

[0059] Cellulose macromolecules are composed of β-D-glucose residues linked to each other 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 isatoic anhydride derivatives, sufficient aromatic primary amine groups can be introduced into the cellulose fibers. Isatoic anhydride-modified cellulose can be prepared into diazotized cellulose through a diazotization reaction, and then undergo a color development reaction with a coupling component, thereby realizing room temperature salt-free rapid diazotization-coupling dyeing of isatoic anhydride-modified cellulose fibers.

[0060] By using the alkali boiling method to remove the dyes on the cellulose fibers, decolorized cellulose fibers with higher whiteness can be obtained, which is conducive to the recycling and reuse of cellulose fibers. Decolorization conditions: NaOH 10-70g / L, temperature 100℃, 20-40min.

[0061] The room temperature salt-free rapid diazotization-coupling dyeing and hydrolysis decolorization mechanism of isatoic anhydride modified cellulose fibers are as follows:

[0062]

[0063] In the present invention, the natural fiber cotton, linen, bamboo fiber and artificial fiber viscose fiber bulk fibers and fabrics woven therefrom, as well as blended fabrics made from these fibers, and blended fabrics made from these fibers and chemical fibers or other types of natural fibers are all commonly known fabrics and can be purchased on the market.

[0064] In the present invention, the isatoic anhydride derivatives (CAS: 118-48-9, etc.) used can be commercially available.

[0065] In the present invention, the hydrochloric acid, glacial acetic acid, sodium nitrite, urea, sodium hydroxide, sodium carbonate, coupling components and other substances used are all commonly known chemical products, which can be purchased commercially or synthesized according to literature methods (such as coupling components containing monoazo structures).

[0066] For the cellulose fibers obtained by the dyeing method provided in the present invention, the washing fastness, rubbing fastness and light fastness are tested according to the national standards commonly used in this field.

[0067] In the present invention, cellulose fibers are modified at room temperature using isatoic anhydride derivatives, and dyeing can be completed quickly at room temperature through further diazotization coupling reaction; whereas the reactive dye dyeing in the prior art requires a longer reaction time and a higher temperature;

[0068] The isatoic anhydride-modified cellulose modified by isatoic anhydride derivatives is diazotized, and the diazonium salt formed by the diazotized cellulose is relatively stable and can be stored at room temperature; however, in the prior art, the diazonium salt needs to be stored at 0-5°C and cannot be stored for a long time, and must be prepared and used immediately;

[0069] Coupled dyeing can covalently bond with cellulose fibers at room temperature; however, the existing technology requires covalent bonding at 0 to 5°C.

[0070] The present invention has the following beneficial effects:

[0071] The present invention successfully realizes efficient primary aromatic amination modification of cellulose fiber under room temperature by changing solvent, adding alkali and adding catalyst, and further merges the synthesis process of azo dye with the dyeing process of cellulose fiber through room temperature diazotization and coupling dyeing, realizes the whole process room temperature operation of the three-step chemical modification process of primary aromatic amination modification→diazotization→coupling dyeing, greatly reduces dyeing energy consumption, shortens the total time of dye production and dyeing, and also avoids the discharge of high-salt colored wastewater caused by the addition of a large amount of dyeing salt in the dyeing process, realizes an environmentally friendly green dyeing method, and also improves the dyeing depth, washing fastness, rubbing fastness, light fastness, etc. of the dyed cellulose fiber, so that the application performance of the product is improved, and also provides a new energy-saving and emission-reducing type cellulose fiber reactive dyeing method for cellulose fiber. In addition, the dyed cellulose fiber obtained by the method adopts an alkali solution boiling method to easily remove the dye on the cellulose fiber, obtain a higher whiteness, and maintain a good fiber strength, which is conducive to the recycling and reuse of the cellulose fiber.

[0072] The present invention can utilize less diazotization reagent to achieve a good diazotization conversion rate.

[0073] The invention can realize recycling, and the coupling component solution after coupling dyeing can be recycled, that is, the coupling component is supplemented to the coupling component solution after coupling dyeing to the required concentration, and can be used for the next batch of coupling dyeing, thereby having the advantages of reducing environmental pollution and being green and environmentally friendly.

[0074] The dyeing method provided by the invention is used to dye cellulose fiber fabrics such as cotton, linen, bamboo, and viscose, with low dyeing energy consumption and short dyeing time. The dyed fabrics have bright color, high color depth, good color fastness, and strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0076] Figure 1 The K / S curve of the coupled dyed cotton fabric obtained in Example 1 and DMF stripping is shown;

[0077] Figure 2 The K / S curve of the coupled dyed cotton fabric obtained in Example 2 and DMF stripping is shown;

[0078] Figure 3 The K / S curve of the coupled dyed cotton fabric obtained in Example 3 and DMF stripping is shown. DETAILED DESCRIPTION

[0079] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0080] The room temperature in the present invention refers to 20 to 40° C. (preferably 30° C.) The concentration of concentrated hydrochloric acid is 36% to 38%.

[0081] Example 1: A room temperature salt-free rapid reactive dyeing and recycling method for cellulose fibers:

[0082] The cellulose fiber is 10 g of cotton fabric, the dyeing bath ratio of step 3) is 1:20, and the following steps are performed in sequence:

[0083] 1) Aromatic amination modification of cotton fabric with isatoic anhydride:

[0084] DMF (N,N-dimethylformamide) and water were mixed in a volume ratio of 1:24 as a solvent;

[0085] 10g of cotton fabric was immersed in 500mL of solvent containing 0.3g (0.0018mol) of isatoic anhydride, 0.03g of DMAP was added, and sodium carbonate solution was added to adjust the pH of the reaction system to 9.0, and the reaction was carried out at 30°C for 2h to complete the modification. Then, the fabric was washed in hot water at 60±10°C for 10min, and then washed in cold water at 5-10°C to obtain isatoic anhydride modified cotton fabric.

[0086] Note: The purpose of hot water and cold water washing is to remove unreacted isatoic anhydride and its hydrolysis products on cellulose fibers.

[0087] 2) Diazotization of isatin anhydride modified cotton fabric:

[0088] Mix concentrated hydrochloric acid containing 0.002 mol of HCl with 15 mL of water to obtain a hydrochloric acid solution;

[0089] Mix 0.002 mol of sodium nitrite with 1 mL of water to make an aqueous solution of sodium nitrite;

[0090] The isocyanate anhydride modified cotton fabric obtained in step 1) is placed in the above 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, urea can be used to remove excess nitrous acid; then the fabric is taken out, washed with cold water, and then blown dry (until it is basically free of water, that is, the moisture content is ≤2%) to obtain a diazotized cotton fabric.

[0091] It is a common technique to remove excess nitrous acid using urea.

[0092] 3) Coupling dyeing of diazotized cotton fabric:

[0093] 1-Phenyl-3-methyl-5-pyrazolone was selected as the yellow coupling component, and its structural formula is:

[0094]

[0095] 1-phenyl-3-methyl-5-pyrazolone and water are mixed to form a coupling component solution, in which the concentration of 1-phenyl-3-methyl-5-pyrazolone is 2 g / L.

[0096] Under continuous shaking, the diazotized cotton fabric obtained in step 2) is placed in the coupling component solution and immersed in the reaction (coupling color development reaction) at room temperature for 10 minutes to achieve dyeing. During the reaction, the pH of the system is always controlled to be 8-9.

[0097] After the set reaction time is up, the fabric is taken out and then the surface floating color is removed by soap washing (1g of cloth, 0.25g of soap flakes, 50°C for 45min), then washed alternately 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.

[0098] 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.

[0099] Verification experiment: DMF high temperature stripping method (110℃, 30min) was used to bond the dyes on the coupled dyed cotton fabric. Figure 1 It can be seen that the K / S value of the dyed cotton fabric (i.e., K / S before DMF stripping) is 17.2, and the K / S value after DMF stripping is 17.8, with little change, thus proving that the dye forms a covalent bond with the fiber.

[0100] 4) The dye on the coupled dyed cotton fabric obtained in step 3) is removed by boiling with alkali solution to achieve the recycling and reuse of cotton fibers.

[0101] The decolorization process using the alkali boiling method is as follows: according to the bath ratio of 1:30, the dyed cotton fabric is placed in an alkali solution with a NaOH concentration of 40g / L and boiled (about 100°C) for 40 minutes. After decolorization, the K / S ratio drops to 0.02, the blue light whiteness reaches 71.3, and the fiber strength loss rate is only 4.2%. Therefore, it is proved that the present invention can realize the recycling and reuse of cellulose fibers.

[0102] The blue light whiteness is tested using a conventional testing instrument - a blue light whiteness meter, and the fabric breaking strength loss rate is tested in accordance with GB / T3923.1-2013 Textile fabrics tensile properties Part 1: Determination of breaking strength and elongation at break (strip method).

[0103] Note: The cotton fabric in Example 1 was changed into the sample shown in Table 2 below, and the results obtained were as shown in Table 2 below:

[0104] Table 2

[0105] sample K / S before bleaching After decolorization K / S Blue light whiteness Breaking strength loss rate / % Cotton fabric 17.2 0.02 71.3 4.2 Viscose fabric 15.5 0.11 64.8 4.9 Cotton and viscose blended fabric 16.3 0.08 68.7 4.4

[0106] Embodiment 2,

[0107] The coupling component in step 3) of Example 1 was changed to γ ​​acid: The pH of the system was controlled to be 4-5, and the rest was the same as in Example 1.

[0108] Embodiment 3,

[0109] The coupling component in step 3) of Example 1 was changed to γ ​​acid: The pH of the system was controlled to be 8-9, and the rest was the same as in Example 1.

[0110] It should be noted that: Example 2 belongs to amino ortho-coupling, which is an acidic condition; Example 3 belongs to phenolic hydroxyl ortho-coupling, which is an alkaline condition.

[0111] Similarly, in Examples 4 to 61, the coupling components in Example 1 are changed as described in Table 3 below, and the pH of the system is controlled as described in Table 3 below, and the rest is the same as in Example 1.

[0112] Table 3

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119] Note: γ acid, J acid, H acid, these three acids contain both amino groups and hydroxyl groups, so the coupling pH can be acidic or alkaline, that is, the coupling sites are different, acidic coupling is at the position adjacent to the amino group, and alkaline coupling is at the position adjacent to the hydroxyl group.

[0120] In the above Table 3: most of the H acid-acidic single coupling compounds, H acid-base single coupling compounds, and color-changing acid-base single coupling compounds are known compounds (CAS numbers are as described in Table 3), and the rest can be prepared by referring to the existing technology.

[0121] The breaking strength loss rates of the above-mentioned Examples 2 to 61 are all lower than 6%.

[0122] In Example 62 to Example 71, the isatoic anhydride in step 1) of Example was replaced with the isatoic anhydride derivatives described in Table 4 below, and the rest was the same as in Example 1. The final results of the cotton fabric are shown in Table 4 below.

[0123] Table 4

[0124]

[0125]

[0126] Note: The fibers of Examples 62 to 71 are all yellow in color, and the breaking strength loss rates are all lower than 6%.

[0127] Due to the shrinkage of the fabric structure after DMF stripping, the K / S after DMF stripping in Example 1 is slightly greater than the K / S before DMF stripping, while the K / S after DMF stripping in Examples 62 to 71 are all ≤ their corresponding K / S before DMF stripping.

[0128] Comparative Example 1-1, the use of the catalyst 4-dimethylaminopyridine (DMAP) in step 1) of Example 1 was eliminated, and the step of "adding sodium carbonate solution to adjust the pH of the reaction system to 9.0" was eliminated, and the reaction was carried out at 100° C. for 6 hours to complete the modification.

[0129] The rest is the same as Example 1.

[0130] The K / S value of the dyed cotton fabric (ie, K / S before DMF stripping) is 8.7, which is much lower than 17.2 corresponding to Example 1.

[0131] In Comparative Example 1-1, the modification rate was low due to the hydrolysis of isatoic anhydride and the like.

[0132] Comparative Example 1-2: Changing the reaction temperature in Comparative Example 1-1 from "100°C" to 30°C as in the present invention requires at least 12 hours to complete the modification.

[0133] The rest is the same as Example 1.

[0134] The K / S value of dyed cotton fabric is 10.4.

[0135] In Comparative Example 1-2, the modification rate was low due to the hydrolysis of isatoic anhydride.

[0136] Comparative Example 2-1: The solvent in Example 1 was changed from "DMF and water mixed in a volume ratio of 1:24" to all DMF, and the rest was the same as Example 1.

[0137] The K / S value of dyed cotton fabric is 13.4.

[0138] Comparative Example 2-2: The solvent in Example 1 was changed from "DMF and water mixed in a volume ratio of 1:24" to "DMF and water mixed in a volume ratio of 1:1", and the rest was the same as Example 1.

[0139] The K / S value of the dyed cotton fabric is 17.0. Although the K / S value of the dyed cotton fabric in this case is close to that in Example 1, the addition of excessive DMF is disadvantageous to cost and environmental protection, and therefore it is not recommended.

[0140] Experiment 1: The cotton fabric A1 used in Example 1 and the above four comparative examples was tested according to the color fastness to soaping "GB / T3921-2008", the color fastness to rubbing "GB / T 3920-2008" and the color fastness to light "GB / T 8427-2019":

[0141] The results are shown in Table 5 below:

[0142] Table 5

[0143] Dry rubbing fastness Wet rubbing fastness Color fastness to soap washing Color fastness to light Example 1 4-5 4 4-5 6-7 Comparative Example 1-1 4-5 4 4-5 5-6 Comparative Example 1-2 4-5 4 4-5 6 Comparative Example 2-1 4-5 4 4-5 6 Comparative Example 2-2 4-5 3-4 4-5 6-7

[0144] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A room temperature salt-free rapid reactive dyeing method for cellulose fibers, characterized in that The following steps are involved: 1) Cellulose fibers modified with isatoic anhydride derivatives: Add cellulose fiber, isocyanate anhydride and its derivatives and catalyst into the solvent to form a modification system, then add alkali to adjust and maintain the pH of the modification system at 7.5-9.0, and carry out modification reaction at a reaction temperature of 20-40°C and a reaction time of 0.5-5h; The amount of isatoic anhydride and its derivatives is 0.01% to 10% of the mass of the cellulose fiber; The catalyst is 4-dimethylaminopyridine; the amount of 4-dimethylaminopyridine used is 1% to 10% of the mass of isatoic anhydride and its derivatives; After the reaction is completed, post-treatment is performed to obtain isatoic anhydride-modified cellulose; The solvent is composed of a co-solvent and water, wherein the volume ratio of the co-solvent to water is 2% to 60%; the co-solvent is N,N-dimethylformamide, DMSO or dioxane; The base is sodium carbonate or potassium acetate; The usage ratio of cellulose fiber to solvent is 1g:5-100ml; 2) Diazotization of isatoic anhydride modified cellulose: At room temperature, diazotizing the isatoic anhydride-modified cellulose obtained in step 1) using a diazotizing agent to obtain diazotized cellulose; 3) Coupling dyeing of diazotized cellulose: Mixing the coupling component and water to form a coupling component solution, wherein the concentration of the coupling component in the coupling component solution is 2±0.2 g / L; The diazotized cellulose fiber obtained in step 2) is mixed with the coupling component solution according to a coupling dyeing bath ratio of 1 g: 5 to 100 mL, and a coupling color development reaction is carried out at room temperature. During the reaction, the pH is controlled to be 4 to 10, thereby generating coupled dyed fibers; and then soap washing is carried out to obtain soap washed coupled dyed fibers.

2. The room temperature salt-free rapid reactive dyeing method for cellulose fibers according to claim 1, characterized in that: It also includes the following step 4): 4) The dye on the soap-washed coupled-dyed fiber obtained in step 3) is removed by boiling with alkali solution to achieve the recycling and reuse of the cellulose fiber.

3. The room temperature salt-free rapid reactive dyeing method for cellulose fibers according to claim 1 or 2, characterized in that In the step 1), the isatoic anhydride derivatives include isatoic anhydride, 4-chloroisatoic anhydride, 4-bromoisatoic anhydride, 4-nitroisatoic anhydride, 3-chloroisatoic anhydride, 6-methylisatoic anhydride, 4-methylisatoic anhydride, 5-fluoroisatoic anhydride, 5-nitroisatoic anhydride, 5-bromoisatoic anhydride, 5-chloroisatoic anhydride, and 4,5-dimethoxyisatoic anhydride.

4. The room temperature salt-free rapid reactive dyeing method for cellulose fibers according to claim 3, characterized in that The post-treatment in step 1) is: firstly washing in hot water at 60±10° C., and then washing in cold water at 5-10° C.; to obtain isatoic anhydride modified cellulose.

5. The room temperature salt-free rapid reactive dyeing method for cellulose fibers according to claim 4, characterized in that The step 2): the diazotization reagent is composed of sodium nitrite and acid; The isatoic anhydride modified cellulose obtained in step 1) is placed in an acid aqueous solution, and then a NaNO2 aqueous solution is added, and the mixture is stirred and reacted at room temperature for 10 to 30 minutes; the molar ratio of the acid to NaNO2 is 1:(1.01±0.01), and (0.002±0.0001) mol of acid is used for every 10 g of cellulose fiber; The cellulose after the reaction is taken out, washed with water and then blown dry to obtain diazotized cellulose.

6. The room temperature salt-free rapid reactive dyeing method for cellulose fibers according to claim 5, characterized in that: In step 2), the acid is hydrochloric acid, sulfuric acid, or glacial acetic acid; In the step 3), the coupling components are aromatic amine compounds, phenolic compounds, active methylene compounds, and monoazo dyes containing coupling sites.

7. The room temperature salt-free rapid reactive dyeing method for cellulose fibers according to claim 6, characterized in that In the step 3): Aromatic amine compounds are H acid, J acid, and γ acid; The phenolic compounds are N-acetyl H acid, 2-naphthol, chromotropic acid, p-phenylphenol, G salt, Schaffer acid, R acid, N-acetyl gamma acid, NW acid, FC acid, 2,3-acid, salicylic acid, N-acetyl J acid; Active methylene compounds are pyrazolone, pyridone and their derivatives; Pyrazolone derivatives include 1-phenyl-3-methyl-5-pyrazolone, 1-(4-sulfonate phenyl)-3-methyl-5-pyrazolone, 1-(2,5-dichloro-4-sulfonate phenyl)-3-methyl-5-pyrazolone, 3-carboxy-1-(4-sulfonate phenyl)-5-pyrazolone; Pyridone derivatives include 3-cyano-1,4-dimethyl-6-hydroxy-2-pyridone, N-ethyl-3-cyano-4-methyl-6-hydroxy-2-pyridone; The monoazo dyes containing coupling sites include H acid-acidic coupling monocoupling compounds, H acid-base coupling monocoupling compounds, and color-changing acid-base coupling monocoupling compounds.

8. The room temperature salt-free rapid reactive dyeing method for cellulose fibers according to claim 7, characterized in that The step 3) is: Under constant shaking, the diazotized cellulose obtained in step 2) is placed in the coupling component solution and soaked at room temperature for 10 to 20 minutes to achieve coupling color development and generate coupled dyed fibers; Then, the coupled dyed fiber is soaped to remove the floating color and dried to obtain the dyed cellulose fiber; The soap washing method for removing floating color is as follows: 1g of cloth and 0.25g of soap flakes are washed at 50°C for 45min.

9. The room temperature salt-free rapid reactive dyeing method for cellulose fibers according to claim 8, characterized in that The step 4) is as follows: prepare 10-70 g / L NaOH solution as alkali solution, put the soap-washed coupled dyed fiber obtained in step 3) into the alkali solution at a bath ratio of 1:30, and decolorize at 95-100° C. for 20-40 minutes.

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