Wool fibers and their dyeing methods, ionic liquids and their preparation methods

Abstract

This disclosure relates to the field of fiber dyeing technology, and in particular to a wool fiber and its dyeing method, an ionic liquid and its preparation method. The dyeing method includes: S1, mixing compound X, CH3Br, and an aromatic hydrocarbon solvent according to a first preset molar ratio, reacting at a first preset temperature for a first preset time under inert gas protection, extracting the product after the reaction with an extractant, distilling the lower viscous liquid after extraction, and then drying at a second preset temperature for a second preset time to obtain an ionic liquid, wherein the structural formula of compound X is [insert structural formula here], and R1 is ethyl, n-propyl, or n-butyl; S2, dissolving a bio-derived dye in the ionic liquid to form a dye solution; then completely immersing the wool fiber raw material in the dye solution, dyeing at a third preset temperature for a third preset time, washing the dyed wool fiber raw material with ethanol a preset number of times, and then vacuum drying at a fourth preset temperature for a fourth preset time to obtain wool fiber.

Description

Technical Field

[0001] This disclosure relates to the field of fiber dyeing technology, and in particular to a wool fiber and its dyeing method, an ionic liquid and its preparation method. Background Technology

[0002] Wool fibers are primarily composed of protein, with a unique scaly layer structure on their outermost layer. This structure presents numerous challenges to wool dyeing, finishing, and its performance in use. On one hand, the presence of the scaly layer creates a "directional friction effect," making wool prone to felting and shrinkage. On the other hand, the presence of highly hydrophobic lipid structures, along with numerous amide and disulfide crosslinks, within the scaly layer results in an exceptionally dense structure. This severely hinders the spreading and adsorption of various chemical finishing agents on the fiber surface, impacting dyeing, printing, and other finishing processes. Traditional physical methods, such as ultrasonic treatment, are ineffective at damaging the dense wool scales and can only be used as supplementary methods. Plasma treatment can improve the hydrophilicity of wool, but its application is limited by equipment issues. Chemical methods primarily involve oxidation, with chlorine-containing oxidants showing the best results. Oxidation of disulfide bonds within the fiber produces a large number of sulfonic acid groups, causing some of the scaly layer to swell and soften, improving dyeing performance. However, residual chlorine reacts with amino acids in the cortex, damaging the main body of the wool fiber. Furthermore, commonly used biological methods suffer from high costs and require combination with physical or chemical methods to achieve optimal results. Currently, due to the dense and complex structure of wool scales, the aforementioned processing typically requires high temperatures, high concentrations of processing agents, and high solid-liquid ratios, leading to significant pollution from waste gas, wastewater, and solid waste. Moreover, various methods developed to date, including enzymatic and non-aqueous solvent methods, still suffer from low efficiency, the need for auxiliary agents or demanding conditions, and potential environmental hazards.

[0003] To address the aforementioned issues, existing technologies typically employ non-aqueous systems such as supercritical carbon dioxide solvents and ionic liquids to color wool fibers. This method involves pretreating the wool fibers with ionic liquids during the dyeing process to improve surface properties, thereby achieving the desired dyeing effect. It is characterized by its environmental friendliness and high dyeing performance. Reference 1 (Anecofriendly dyeing of wool with supercritical carbon dioxide fluid[J]. Journal of Cleaner Production, 2017, 143: 269) studied the dyeing performance of wool fibers in supercritical carbon dioxide and found that the dyeing rate and fixation rate of CI Disperse Red 153 and CI Disperse Blue 148 were superior to other disperse dyes. Furthermore, wool fibers dyed with supercritical carbon dioxide exhibited good air permeability and color fastness, but their breaking strength and tensile strength were slightly reduced, limiting its practical application.

[0004] As a green solvent, ionic liquids are typically colorless and odorless, non-volatile, have a wide liquid range, high thermal stability, and broad solubility and miscibility compared to traditional organic solvents. They can be designed as solvents by adjusting the combination of anions and cations, and are easy to recycle. Therefore, they have applications in many fields such as chemistry, materials, and environment. Reference 2 (Hydrophilic modification treatment of wool with ionic liquid BmimCl / DMSO[J]. Dyeing and Printing, 2019, 20: 1) introduces the co-solvent DMSO to reduce its viscosity. The strong dissolving ability of the ionic liquid can dissolve and swell the wool scale layer, effectively remove lipids and high-sulfur proteins from the scale layer, reduce the density of the scale, improve the hydrophilicity of wool, and break the barrier of bio-derived dye molecules to enter the wool fiber, thereby improving the wearing performance of wool. However, a co-solvent needs to be introduced, which will lead to a significant decrease in wool strength and no antibacterial function of the fiber. In addition, nitrogen-containing substances in wool will react with chlorine, causing the fiber to turn yellow, and the wastewater after treatment contains a large amount of organic halides, which are carcinogenic and easily cause environmental pollution; Reference 3 (Influence of Acetate-Based and Bromo-Based Ionic Liquids Treatment on Wool Dyeing with Acid Blue 7[J]. Journal of Applied Polymer Science, 2012, 123 (6): 3283) The dyeing properties of wool fibers treated with ionic liquids and their acid dyes were studied. The results showed that wool samples treated with acetate-based ionic liquids, especially wool samples treated with 1-ethyl-3-methylimidazolium acetate, had higher initial dyeing rate and equilibrium dyeing rate than wool samples treated with bromine-based ionic liquids. However, the color fastness of the wool fibers was not high and they had no antibacterial ability.

[0005] Therefore, it is of great significance to study an efficient and environmentally friendly dyeing method for wool fibers to solve the above problems. Summary of the Invention

[0006] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a wool fiber and a dyeing method thereof, an ionic liquid and a preparation method thereof.

[0007] This disclosure provides a method for dyeing wool fibers, the dyeing method comprising the following steps: S1. Preparation of ionic liquid: Compound X, CH3Br, and an aromatic hydrocarbon solvent are mixed according to a first preset molar ratio and reacted at a first preset temperature for a first preset time under inert gas protection. The product after reaction is extracted with an extractant, and the lower viscous layer after extraction is distilled and then dried at a second preset temperature for a second preset time to obtain the ionic liquid. The structural formula of compound X is as follows: R1 is ethyl, n-propyl, or n-butyl; S2. Ionic liquid dyeing: Dissolve the bio-derived dye in an ionic liquid to form a dye solution; then completely immerse the wool fiber raw material in the dye solution and dye it at a third preset temperature for a third preset time. After dyeing, the wool fiber raw material is washed with ethanol a preset number of times and then vacuum dried at a fourth preset temperature for a fourth preset time to obtain wool fiber.

[0008] In one embodiment of this disclosure, the inert gas is one of nitrogen, helium, and argon; The aromatic hydrocarbon solvent is one of toluene, p-xylene, m-xylene, o-xylene, and mesitylene; The extractant is one of methyl acetate, ethyl acetate, or propyl acetate.

[0009] In one embodiment of this disclosure, the first preset molar ratio of compound X, CH3Br, and aromatic hydrocarbon solvent is 1:1.1-1.3:100-1000.

[0010] In one embodiment of this disclosure, compound X is obtained by reacting SO2F2, 1-methylimidazol-2-thiol, thiol Y, triethylamine, and acetonitrile at a second preset molar ratio and a fifth preset temperature, wherein the thiol Y is one of ethanethiol, 1-propanethiol, and 1-butanethiol.

[0011] In one embodiment of this disclosure, the second preset molar ratio of SO2F2, 1-methylimidazol-2-thiol, thiol Y, triethylamine, and acetonitrile is 0.1-0.5:1:1.5-3:10-30:100-1000.

[0012] In one embodiment of this disclosure, the fifth preset temperature is 40-60°C.

[0013] In one embodiment of this disclosure, the first preset temperature is 80-90°C and the first preset duration is 3-6 hours.

[0014] In one embodiment of this disclosure, the second preset temperature is 70-85°C, and the second preset duration is 12-24h.

[0015] In one embodiment of this disclosure, the recovery rate of the ionic liquid is 95.5%-99.5%.

[0016] In one embodiment of this disclosure, the mass ratio of the wool fiber raw material, the bio-derived dye, and the ionic liquid is 1:0.1-0.5:50-200.

[0017] In one embodiment of this disclosure, the bio-derived dye is one of naringenin, epicatechin, natural indigo, carmine, and tannic acid.

[0018] In one embodiment of this disclosure, the third preset temperature is 50-70°C and the third preset duration is 20-40 minutes.

[0019] In one embodiment of this disclosure, the pH value of the ionic liquid is 4-5.

[0020] In one embodiment of this disclosure, the preset number of ethanol washes is 3-5 times.

[0021] In one embodiment of this disclosure, the fourth preset temperature is 60~80℃, and the fourth preset duration is 60~120min.

[0022] This disclosure also provides a wool fiber obtained by the dyeing method of wool fiber described in any of the above embodiments.

[0023] This disclosure also provides a method for preparing an ionic liquid, comprising: Compound X, CH3Br, and an aromatic hydrocarbon solvent are mixed in a first preset molar ratio and reacted at a first preset temperature for a first preset time under an inert gas atmosphere. The reaction product is extracted with an extractant, and the lower viscous layer after extraction is distilled and then dried at a second preset temperature for a second preset time to obtain an ionic liquid. The structural formula of compound X is as follows: R1 is ethyl, n-propyl, or n-butyl.

[0024] In one embodiment of this disclosure, the inert gas is one of nitrogen, helium, and argon; The aromatic hydrocarbon solvent is one of toluene, p-xylene, m-xylene, o-xylene, and mesitylene; The extractant is one of methyl acetate, ethyl acetate, or propyl acetate.

[0025] In one embodiment of this disclosure, the first preset molar ratio of compound X, CH3Br, and aromatic hydrocarbon solvent is 1:1.1-1.3:100-1000.

[0026] In one embodiment of this disclosure, compound X is obtained by reacting SO2F2, 1-methylimidazol-2-thiol, thiol Y, triethylamine, and acetonitrile at a second preset molar ratio and a fifth preset temperature, wherein the thiol Y is one of ethanethiol, 1-propanethiol, and 1-butanethiol.

[0027] In one embodiment of this disclosure, the second preset molar ratio of SO2F2, 1-methylimidazol-2-thiol, thiol Y, triethylamine, and acetonitrile is 0.1-0.5:1:1.5-3:10-30:100-1000.

[0028] In one embodiment of this disclosure, the fifth preset temperature is 40-60°C.

[0029] In one embodiment of this disclosure, the first preset temperature is 80-90°C and the first preset duration is 3-6 hours.

[0030] In one embodiment of this disclosure, the second preset temperature is 70-85°C, and the second preset duration is 12-24h.

[0031] This disclosure also provides an ionic liquid, which is prepared by the ionic liquid preparation method described in the above embodiments.

[0032] One beneficial effect of the wool fiber dyeing method disclosed herein is that the ionic liquid prepared in this method not only acts as a dyeing bath during the dyeing process but also as an auxiliary reagent. On the one hand, it can form hydrogen bonds and dynamic covalent bonds with the wool fibers. On the other hand, the ionic liquid aligns in an orderly manner through newly formed hydrogen bonds with bio-based dye molecules, thereby promoting the directional adsorption of bio-based dye molecules by the wool fibers, resulting in better dyeing effects and achieving high dyeing rate and high color fastness. The selected bio-based dyes, due to their aromatic and highly conjugated structure, can insert their conjugated rigid groups into the cell walls of bacteria, giving the dyed wool fibers excellent antibacterial properties. Furthermore, bio-based dyes also have the advantages of being green and environmentally friendly. Attached Figure Description

[0033] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the present disclosure and, together with their description, serve to explain the principles of the present disclosure.

[0034] Figure 1 This is a flowchart of a method for dyeing wool fibers provided in one embodiment of this disclosure; Figure 2 As in Example 1 The hydrogen spectrum ( 1 H NMR), the horizontal axis PPM represents displacement; Figure 3 As in Example 1 carbon spectrum ( 13 (C NMR). Figure 4 As in Example 1 The hydrogen spectrum ( 1 H NMR), the horizontal axis PPM represents displacement; Figure 5 As in Example 1 carbon spectrum ( 13 (C NMR). Figure 6 Example 4 The hydrogen spectrum ( 1 H NMR), the horizontal axis PPM represents displacement; Figure 7 Example 4 carbon spectrum ( 13 (C NMR). Figure 8 Example 4 The hydrogen spectrum ( 1 H NMR), the horizontal axis PPM represents displacement; Figure 9 Example 4 carbon spectrum ( 13 (C NMR). Figure 10 Example 7 The hydrogen spectrum ( 1 H NMR), the horizontal axis PPM represents displacement; Figure 11 Example 7 carbon spectrum ( 13 (C NMR). Figure 12 Example 7 The hydrogen spectrum ( 1 H NMR), the horizontal axis PPM represents displacement; Figure 13 Example 7 carbon spectrum ( 13 C NMR). Detailed Implementation

[0035] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0036] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0037] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0038] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0040] In this article, terms such as "up," "down," "front," "back," "left," and "right" are used only to indicate the relative positional relationship between related parts, rather than to define the absolute position of these related parts.

[0041] In this article, "first," "second," etc., are used only to distinguish one another, and not to indicate degree of importance, order, or prerequisite for each other.

[0042] In this document, terms such as “equal” and “same” are not strict mathematical and / or geometric limitations, but also include errors that are understandable to those skilled in the art and permissible in manufacturing or use.

[0043] Because the outermost layer of wool fiber has a special scaly structure, it severely hinders the spreading and adsorption of various chemical finishing agents on the fiber surface, affecting wool dyeing, printing, and various finishing processes. Existing technologies use non-aqueous systems such as supercritical carbon dioxide solvents and ionic liquids to color wool fibers. This method involves pre-treating the wool fibers with ionic liquids during the dyeing process to improve surface properties, thereby achieving the dyeing effect. However, the breaking strength and tensile strength of the dyed wool fibers are slightly reduced, limiting its practical application, and the fibers lack antibacterial properties. Therefore, this disclosure provides a wool fiber and its dyeing method, as well as an ionic liquid and its preparation method. For ease of understanding, please refer to the following... Figures 1-13 The present invention will be described in detail with reference to the embodiments, including wool fibers and dyeing methods thereof, ionic liquids and preparation methods thereof.

[0044] The test methods for the relevant performance indicators in the following embodiments and comparative examples are as follows: K / S value and color difference: The K / S value of the wool fibers prepared in each example was tested using a colorimeter under a D65 light source and a 10° viewing angle. , , The value is calculated, and the color difference ΔE is calculated according to the formula. Five points are randomly tested on each wool fiber, and the average value is taken. The formula for calculating the color difference ΔE is: In the formula, For changes in brightness; For changes in red-green hue; This represents the variation in yellow-blue tint.

[0045] Dye uptake rate: The absorbance of the dye liquor was measured using a spectrophotometer to determine the maximum absorption wavelength. Then, the absorbance of the dye liquor before dyeing and the residual liquor after dyeing were measured at the maximum absorption wavelength. Dye uptake rate = (1-Ai / A0)×100%, where: A0 is the absorbance of the dye liquor before dyeing and Ai is the absorbance of the residual liquor after dyeing.

[0046] Color fastness to sunlight: The high color fastness antibacterial wool fibers prepared in each example were tested according to GB / T 8426—1998 "Textiles - Tests for color fastness to light - Color fastness to sunlight".

[0047] Color fastness to washing: The high color fastness antibacterial wool fibers prepared in each example were tested according to GB / T 3921—2008 "Textiles - Tests for color fastness to washing".

[0048] Color fastness to dry rubbing: The high color fastness antibacterial wool fibers prepared in each example were tested according to GB / T 3920—2008 "Textiles - Tests for color fastness to rubbing".

[0049] Color fastness to perspiration: The high color fastness antibacterial wool fibers prepared in each example were tested according to GB / T 3922—2013 "Textiles - Tests for color fastness to perspiration".

[0050] Breaking strength: The high color fastness antibacterial wool fibers prepared in each embodiment were tested according to GB / T 27629-2011 standard.

[0051] Elongation at break: The high color fastness antibacterial wool fibers prepared in each example were measured according to GB / T 3923.1-2013 standard.

[0052] Antibacterial rate: The high color fastness antibacterial wool fibers prepared in each example were tested according to GB / T 20944.3-2008 standard.

[0053] Recovery rate: The ionic liquid used before dyeing wool fibers is called m1; the ILs separated from the dyed wool fibers by filtration are called m2. Recovery rate = m2 / m1.

[0054] The sources of some of the materials disclosed herein are as follows: Naringenin: CAS: 67604-48-2; Epicatechin: CAS: 490-46-0; Natural indigo: CAS: 482-89-3; Carmine: CAS: 1390-65-4; Tannic acid: CAS: 1401-55-4; 1-Methylimidazol-2-thiol: CAS: 60-56-0; SO2F2: CAS: 2699-79-8.

[0055] Reference Figure 1 This disclosure provides a method for dyeing wool fibers, the dyeing method comprising the following steps: S1, preparing an ionic liquid: mixing compound X, CH3Br, and an aromatic hydrocarbon solvent according to a first preset molar ratio, reacting under an inert gas protection at a first preset temperature for a first preset time, extracting the product after the reaction with an extractant, distilling the lower viscous layer after extraction, and then drying at a second preset temperature for a second preset time to obtain an ionic liquid, wherein the structural formula of compound X is as follows: R1 is ethyl, n-propyl, or n-butyl; S2, ionic liquid dyeing: the bio-derived dye is dissolved in an ionic liquid to form a dye solution; the wool fiber raw material is then completely immersed in the dye solution and dyed at a third preset temperature for a third preset time. After the dyed wool fiber raw material is washed with ethanol a preset number of times, it is vacuum dried at a fourth preset temperature for a fourth preset time to obtain wool fiber.

[0056] Specifically, the ionic liquid prepared in this disclosure not only acts as a dyeing bath during the dyeing process but also as an auxiliary reagent. On the one hand, it can form hydrogen bonds and dynamic covalent bonds with wool fibers. On the other hand, the ionic liquid arranges itself in an orderly manner through newly formed hydrogen bonds with bio-derived dye molecules, thereby promoting the directional adsorption of bio-derived dye molecules by wool fibers and producing better dyeing effects, achieving high dyeing rate and high color fastness. The selected bio-derived dyes, due to their aromatic and highly conjugated structure, can insert their conjugated rigid groups into the cell walls of bacteria, giving the dyed wool fibers excellent antibacterial properties. Furthermore, bio-derived dyes also have the advantages of being green and environmentally friendly. The resulting wool fibers not only have improved mechanical properties but also exhibit high dyeing rate, high color fastness, and good antibacterial properties.

[0057] Furthermore, dyeing performance is improved: On the one hand, during the dyeing process, the cations of the bio-derived dye molecules can first bind to the anions of the ionic liquid. The anionic strength of the ionic liquid is lower than that of a conventional water bath, and hydrogen bonds also exist within it, which may reduce the competition between the anions of the bio-derived dye molecules and the anions of the ionic liquid. In addition, besides the fact that the binding force between the bio-derived dye molecules and wool keratin in the ionic liquid is the same as that in a conventional bath, other binding forces may also contribute to the interaction between the dye molecules and wool. The first binding force is the hydrogen bond between the nitrogen cation of the ionic liquid and the amino group of the wool keratin molecule; the second binding force is the dynamic covalent bond between the disulfide bond of the ionic liquid and the disulfide bond of the wool keratin; and the last binding force is the ionic bond between the carboxyl group of the wool keratin and the anion of the ionic liquid. In other words, the ionic liquid not only acts as a dyeing bath but also as an auxiliary reagent, thus producing a better dyeing effect. On the other hand, the ionic liquid is composed of an imidazole structure and anions bonded by ionic bonds, while the bio-derived dye molecules contain groups such as phenolic hydroxyl groups, both of which have a relatively strong ability to form hydrogen bonds. After the bio-derived dye molecules are added to the ionic liquid, they are arranged in an orderly manner through newly formed hydrogen bonds with the ionic liquid. This reduces the distance between natural bio-derived dye molecules and increases the probability of polymerization between them. The ionic liquid can also form hydrogen bonds, dynamic covalent bonds and other interactions with wool fibers, shortening the distance between the bio-derived dye molecules and the wool fibers. This can promote the directional adsorption of bio-derived dye molecules by the wool fibers, thereby improving the K / S value, dyeing rate and color fastness.

[0058] The increased elongation at break is mainly due to the improved solubility of the ionic liquid by the short alkyl chains linked by disulfide bonds, effectively reducing the viscosity of the ionic liquid. Furthermore, the ionic liquid binds to cations, releasing more anions and increasing the effective anion content for breaking down hydrogen bonds within the wool, thus disrupting the overall long-range structure of the wool protein. To some extent, the disulfide bonds form dynamic covalent bonds with the disulfide bonds in the wool, converting the α-helix portion into a β-sheet, resulting in a decrease in crystallinity. The strong polarity and permeability of the ionic liquid allow it to effectively penetrate the hydrophobic structure and phospholipid structure of the wool's protein cuticle. This causes the low-crosslinked acidic, basic, and polar amino acids on the inner epidermis of the wool cuticle to swell, opening intramolecular hydrogen bonds and interacting with the cationic components in the ionic liquid. This weakens or disrupts the crosslinking between fiber molecules or helical segments, thereby increasing the elongation of the wool fiber.

[0059] Improved mechanical properties: During the dyeing process, the disulfide bonds of the ionic liquid form dynamic covalent bonds with the disulfide bonds in the keratin of wool fibers. After dyeing, the dynamic covalent bonds break without damaging the structure of the wool fibers. Furthermore, the introduced bio-derived dye molecules form hydrogen bonds between wool molecular chains, which plays a role in molecular chain cross-linking, thereby improving the mechanical properties of wool fibers.

[0060] Antibacterial mechanism: Due to their aromatic and highly conjugated structure, rigid bio-derived dye molecules can insert their conjugated rigid groups into the bacterial cell wall. Through contact reactions, they alter the permeability of the bacterial cell membrane, leading to the loss of nutrients and thus inactivating the bacteria. Alternatively, they can inhibit bacterial reproduction and growth by damaging the bacterial genetic material such as DNA and RNA, or inhibit bacterial cell wall synthesis by blocking transglycosylation and transpeptidation processes, thereby achieving beneficial antibacterial properties.

[0061] In one embodiment, the inert gas is one of nitrogen, helium, or argon; the aromatic hydrocarbon solvent is one of toluene, p-xylene, m-xylene, o-xylene, or mesitylene; and the extractant is one of methyl acetate, ethyl acetate, or propyl acetate.

[0062] Specifically, using nitrogen, helium, or argon as inert protective gases can effectively isolate the reaction system from contact with oxygen and moisture in the air, prevent the dyes, reducing sugars, and other reactants from being oxidized and decomposed under heating or alkaline conditions, inhibit side reactions, and improve reaction selectivity and product yield. At the same time, it can maintain the stability of the reaction system atmosphere, reduce problems such as dye color variation and structural damage, ensure the smooth progress of the modification reaction, and improve the consistency and reproducibility of product performance.

[0063] Using toluene, p-xylene, m-xylene, o-xylene, or mesitylene as reaction solvents can achieve good compatibility with ionic liquid intermediates such as imidazole, ensuring homogeneous stability of the reaction system and improving reaction mass transfer efficiency and reaction rate. These aromatic hydrocarbon solvents have extremely low solubility for by-product inorganic salts, which can be directly separated by filtration, simplifying the purification process. At the same time, their moderate boiling points can meet the requirements of reflux temperature control, avoiding high-temperature decomposition of ionic liquids and reducing side reactions. In addition, these solvents do not react with the cations and anions of ionic liquids, and post-processing can be easily carried out by vacuum distillation for removal and recovery, which is beneficial to improving the purity, yield, and performance stability of ionic liquid products.

[0064] Using methyl acetate, ethyl acetate, or propyl acetate as extractants provides excellent selective solubility for the target product, enabling efficient extraction and separation. These ester solvents have moderate polarity, exhibit clear phase separation with the aqueous phase, and are less prone to emulsification, facilitating subsequent phase separation operations. Furthermore, their moderate volatility allows for rapid removal via distillation, minimizing residues that could affect product purity. They are also chemically stable, do not undergo side reactions with the product, and effectively improve separation efficiency and product yield, ensuring stable product quality.

[0065] In one embodiment, the first preset molar ratio of compound X, CH3Br, and aromatic hydrocarbon solvent is 1:1.1-1.3:100-1000.

[0066] Specifically, the reaction is a matter of numbers between molecules, so controlling the molar ratio is to control the precise dosage of the reaction, determine whether the reaction can occur and to what extent, and at the same time reduce side reactions, reduce raw material consumption, and make the reaction system efficient and stable.

[0067] In one embodiment, compound X is obtained by reacting SO2F2, 1-methylimidazol-2-thiol, thiol Y, triethylamine, and acetonitrile at a second preset molar ratio and a fifth preset temperature, wherein thiol Y is one of ethanethiol, 1-propanethiol, and 1-butanethiol.

[0068] Specifically, the preparation process of the above compound X is represented by the following chemical reaction formula: R1 is ethyl, n-propyl, or n-butyl.

[0069] The preparation process of ionic liquids can be represented by the following chemical reaction equation: R1 is ethyl, n-propyl, or n-butyl.

[0070] Furthermore, compound X used for preparing ionic liquids has three forms, with the following structural formulas: , , The ionic liquids were prepared using ethanethiol, 1-propanethiol, and 1-butanethiol as reactants, respectively. The structural formulas of the further prepared ionic liquids are as follows: , , By using different reaction raw materials, the recovery rate of ionic liquids can be improved.

[0071] In one embodiment, the second preset molar ratio of SO2F2, 1-methylimidazol-2-thiol, thiol Y, triethylamine, and acetonitrile is 0.1-0.5:1:1.5-3:10-30:100-1000.

[0072] Specifically, the reaction is a matter of numbers between molecules, so controlling the molar ratio is to control the precise dosage of the reaction, determine whether the reaction can occur and to what extent, and at the same time reduce side reactions, reduce raw material consumption, and make the reaction system efficient and stable.

[0073] In one embodiment, the fifth preset temperature is 40-60°C.

[0074] Specifically, optimizing the reaction temperature can improve reaction selectivity and product yield, facilitating industrial production and application.

[0075] In one embodiment, the first preset temperature is 80-90℃ and the first preset duration is 3-6h.

[0076] Specifically, precise control of reaction temperature and reaction time can effectively control the reaction rate and reaction process, ensuring that compound X is fully dissolved in the aromatic hydrocarbon solvent and reacts fully with CH3Br.

[0077] In one embodiment, the second preset temperature is 70-85°C and the second preset duration is 12-24h.

[0078] Specifically, drying can completely remove residual trace amounts of solvent, moisture, and volatile impurities from the product, further improving the purity of the ionic liquid and preventing residual solvent or moisture from affecting the subsequent dyeing process.

[0079] In one embodiment, the recovery rate of the ionic liquid is 95.5%-99.5%.

[0080] Specifically, the recovery rate of ionic liquids refers to the percentage of the mass of the ionic liquid recovered after separation and purification to the initial mass of the ionic liquid added to the reaction system. It is used to evaluate the retention rate of the ionic liquid during recycling and the economic efficiency of the process. A higher recovery rate indicates less ionic liquid loss and better recycling performance. The ionic liquid prepared in this disclosure has a recovery rate of 95.5%-99.5% and can be recycled.

[0081] In one embodiment, the mass ratio of wool fiber raw material, bio-derived dye, and ionic liquid is 1:0.1-0.5:50-200.

[0082] Specifically, in the dyeing process of wool fibers, precise control of the mass ratio of wool fibers, bio-based dyes, and ionic liquids is crucial to ensuring dyeing effects and product quality. Its core function lies in regulating the concentration of the dyeing system, ensuring that the bio-based dyes are evenly dispersed in the ionic liquid, avoiding uneven dyeing, color spots, or uneven color due to excessively high dye concentration, or insufficient dyeing rate and dyeing depth due to excessively low concentration; coordinating the interaction ratio of wool fibers and dyes promotes the full binding of bio-based dyes with the active groups on the surface of wool fibers, improving dyeing rate and fixation rate, and enhancing color fastness.

[0083] In one embodiment, the bio-derived dye is one of naringenin, epicatechin, natural indigo, carmine, and tannic acid.

[0084] Specifically, naringenin, epicatechin, natural indigo, carmine, or tannic acid are used as bio-derived dyes. The raw materials are derived from natural plants, animals, and biomass, making them renewable and environmentally friendly, effectively reducing dependence on petroleum-based synthetic dyes. These bio-derived dyes have good biocompatibility, low toxicity, and a gentle dyeing process, making them less likely to produce toxic or harmful substances or recalcitrant wastewater, thus meeting green environmental protection and sustainable development requirements. Simultaneously, their molecular structure is rich in active sites such as hydroxyl groups and conjugated systems, allowing for strong bonding with the fiber matrix, resulting in a natural and soft color. They also possess certain antioxidant and antibacterial properties, enhancing the safety and added functions of dyed products, reducing skin irritation, and improving the ecological performance and application value of the products. In particular, their aromatic, highly conjugated structure allows their conjugated rigid groups to insert into the bacterial cell wall, altering the permeability of the bacterial cell membrane through contact reactions, leading to nutrient loss and bacterial inactivation. Alternatively, they can inhibit bacterial growth by damaging bacterial genetic material such as DNA and RNA, and inhibit bacterial cell wall synthesis by hindering transglycosylation and transpeptidation processes, thus achieving beneficial antibacterial properties.

[0085] In one embodiment, the third preset temperature is 50-70°C and the third preset duration is 20-40 minutes.

[0086] Specifically, precise control of dyeing temperature and duration serves several purposes. First, it regulates the dyeing reaction rate, shortens the reaction cycle, and improves dyeing efficiency. Second, it ensures thorough dyeing; a reasonable dyeing duration guarantees sufficient interaction between the dye and wool fibers, preventing problems such as low dye uptake, uneven dyeing, and light color due to insufficient time, while preventing excessive dye aggregation, color shift, fiber damage, and poor hand feel due to excessive time. Third, it stabilizes the dyeing effect; precise temperature and duration control avoids wool fiber degradation and dye structure damage caused by excessively high temperatures, or dyeing reaction stagnation caused by excessively low temperatures. This ensures uniform color, excellent brightness, and stable fastness of the dyed wool fibers, improving dyeing reproducibility and adapting to large-scale industrial dyeing production, balancing dyeing quality and production efficiency.

[0087] In one embodiment, the pH of the ionic liquid is 4-5.

[0088] Specifically, adjusting the pH value of the dye bath can adapt to the interaction characteristics of dyes and wool fibers, promoting the binding of dyes with active groups such as amino and carboxyl groups on the surface of wool fibers, significantly improving dye uptake and fixation rates, and enhancing color fastness. Furthermore, it can stabilize the dye bath system, preventing dye aggregation, degradation, or color shift due to unsuitable pH, ensuring uniform and stable dye bath performance, and avoiding defects such as uneven dyeing and color variations. In addition, a suitable pH value can regulate the dyeing reaction rate, making the dyeing process stable and controllable, improving dyeing reproducibility, and meeting the needs of large-scale industrial dyeing production.

[0089] In one embodiment, the preset number of ethanol washes is 3-5 times.

[0090] Specifically, washing dyed wool fibers multiple times with ethanol can effectively remove residual unreacted dyes, byproducts, and other impurities. By controlling the number of washes, the amount of residual impurities on the surface of the wool fibers can be significantly reduced, improving the purity and appearance clarity of the product.

[0091] In one embodiment, the fourth preset temperature is 60~80℃ and the fourth preset duration is 60~120min.

[0092] Specifically, after washing, the dyed wool fibers are vacuum dried. Precise control of the temperature and duration of vacuum drying can quickly and gently remove residual impurities from the fabric or product, avoid color shift or decrease in color fastness, and further improve product purity and storage stability.

[0093] This disclosure also provides a wool fiber, which is obtained by the dyeing method of the wool fiber described in the above embodiments.

[0094] Specifically, the disclosed wool fiber has a K / S value of 4.5-6.7, a color difference ΔE of 0-0.5, a dyeing rate of 70%-90%, and color fastness to sunlight, washing, dry rubbing, and perspiration of grade 4-5. Its breaking strength is 2.5-3.2 cN / dtex, its breaking elongation is 45%-60%, and its antibacterial rate against Escherichia coli is 99.2%-99.7%, while its antibacterial rate against Staphylococcus aureus is 99.5%-99.9%. The dyeing properties, mechanical properties, UV resistance, and antibacterial properties of the wool fiber are all improved.

[0095] This disclosure also provides a method for preparing an ionic liquid, comprising: mixing compound X, CH3Br, and an aromatic hydrocarbon solvent in a first preset molar ratio, reacting the mixture at a first preset temperature for a first preset time under an inert gas protection, extracting the product with an extractant, distilling the lower viscous layer after extraction, and then drying the product at a second preset temperature for a second preset time to obtain the ionic liquid, wherein the structural formula of compound X is as follows: R1 is ethyl, n-propyl, or n-butyl.

[0096] Specifically, by preparing ionic liquids with high recovery rates, not only is the recycling of ionic liquids achieved, but also, as a subsequent dyeing system, ionic liquids can form hydrogen bonds, dynamic covalent bonds, and other interactions with wool fibers. The ionic liquids are arranged in an orderly manner through the newly formed hydrogen bonds with bio-derived dye molecules, thereby promoting the directional adsorption of bio-derived dye molecules by wool fibers and producing better dyeing effects.

[0097] This disclosure also provides an ionic liquid, which is prepared by the preparation method of the ionic liquid described in the above embodiments.

[0098] Specifically, the ionic liquid disclosed herein has a high recovery rate, and as a subsequent dyeing system, the ionic liquid can form hydrogen bonds, dynamic covalent bonds and other interactions with wool fibers. The ionic liquid is ordered through the newly formed hydrogen bonds with the bio-derived dye molecules, thereby promoting the directional adsorption of bio-derived dye molecules by the wool fibers and thus producing a better dyeing effect.

[0099] To make the technical solutions and advantages of this disclosure clearer, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments listed in this disclosure are only some embodiments, and other embodiments formed by arranging and combining raw materials and conditions are also within the protection scope of this disclosure.

[0100] Example 1 Reference Figures 2-5 A method for dyeing wool fibers, comprising the following steps: (1) Preparation of ionic liquids: SO2F2, 1-methylimidazolium-2-thiol, ethanethiol, triethylamine, and acetonitrile were reacted at a molar ratio of 0.1:1:1.5:10:100 at 40°C for 24 h to give compound X. The structural formula of compound X is [insert structural formula here]. Compound X, CH3Br, and toluene were added and mixed in a molar ratio of 1:1.1:100 in a three-necked flask and reacted at 80°C for 3 h under nitrogen protection. The product was extracted with methyl acetate, and the lower viscous layer after extraction was distilled and then dried at 70°C for 12 h to obtain an ionic liquid with the following structural formula: .

[0101] (2) Staining with ionic liquids: Naringenin was dissolved in an ionic liquid with a pH of 4 to form a dye solution. Wool fiber raw materials were then completely immersed in the dye solution and dyed at a constant temperature of 50°C for 20 minutes. After dyeing, the wool fiber raw materials were washed three times with ethanol and then vacuum dried at 60°C for 60 minutes to obtain wool fibers. The mass ratio of wool fiber, bio-derived dye, and ionic liquid was 1:0.1:50. The recovery rate of the ionic liquid was 95.5%.

[0102] The final wool fiber has a K / S value of 4.5, a color difference ΔE of 0, a dyeing rate of 70%, a color fastness to sunlight of grade 4, a color fastness to soaping of grade 4, a color fastness to dry rubbing of grade 4, a color fastness to perspiration of grade 4, a breaking strength of 2.5 cN / dtex, a breaking elongation of 45%, an antibacterial rate of 99.2% against Escherichia coli, and an antibacterial rate of 99.5% against Staphylococcus aureus.

[0103] Example 2 A method for dyeing wool fibers, comprising the following steps: (1) Preparation of ionic liquids: SO2F2, 1-methylimidazol-2-thiol, ethanethiol, triethylamine, and acetonitrile were reacted at a molar ratio of 0.15:1:1.7:13:200 at 42°C for 27 h to give compound X. The structural formula of compound X is [insert structural formula here]. Compound X, CH3Br, and p-xylene were added to a three-necked flask in a molar ratio of 1:1.13:200 and reacted at 81°C for 3.5 h under helium protection. The product was extracted with methyl acetate, and the lower viscous layer was distilled and then dried at 72°C for 14 h to obtain an ionic liquid with the following structural formula: .

[0104] (2) Staining with ionic liquids: Naringenin was dissolved in an ionic liquid with a pH of 4.1 to form a dye solution. Wool fiber raw materials were then completely immersed in the dye solution and dyed at a constant temperature of 53℃ for 23 minutes. After dyeing, the wool fiber raw materials were washed three times with ethanol and then vacuum dried at 62℃ for 65 minutes to obtain wool fibers. The mass ratio of wool fiber, bio-derived dye, and ionic liquid was 1:0.15:70. The recovery rate of the ionic liquid was 95.8%.

[0105] The final wool fiber has a K / S value of 4.7, a color difference ΔE of 0.08, a dyeing rate of 73%, a color fastness to sunlight of grade 4, a color fastness to soaping of grade 4, a color fastness to dry rubbing of grade 4-5, a color fastness to perspiration of grade 4-5, a breaking strength of 2.5 cN / dtex, a breaking elongation of 47%, an antibacterial rate of 99.2% against Escherichia coli, and an antibacterial rate of 99.6% against Staphylococcus aureus.

[0106] Example 3 A method for dyeing wool fibers, comprising the following steps: (1) Preparation of ionic liquids: SO2F2, 1-methylimidazolium-2-thiol, ethanethiol, triethylamine, and acetonitrile were reacted at a molar ratio of 0.2:1:1.9:15:300 at 44°C for 30 h to obtain compound X. The structural formula of compound X is [insert structural formula here]. Compound X, CH3Br, and m-xylene were added to a three-necked flask in a molar ratio of 1:1.13:200 and reacted at 82°C for 4 h under argon protection. The product was extracted with methyl acetate, and the lower viscous layer was distilled and then dried at 74°C for 16 h to obtain an ionic liquid with the following structural formula: .

[0107] (2) Staining with ionic liquids: Epicatechin was dissolved in an ionic liquid with a pH of 4.2 to form a dye solution. Wool fiber raw materials were then completely immersed in the dye solution and dyed at a constant temperature of 55°C for 25 minutes. The dyed wool fiber raw materials were washed four times with ethanol and then vacuum dried at 65°C for 70 minutes to obtain wool fiber. The mass ratio of wool fiber, bio-derived dye, and ionic liquid was 1:0.2:90. The recovery rate of the ionic liquid was 96.3%.

[0108] The final wool fiber has a K / S value of 4.9, a color difference ΔE of 0.13, a dyeing rate of 75%, a color fastness to sunlight of grade 4-5, a color fastness to soaping of grade 4, a color fastness to dry rubbing of grade 4-5, a color fastness to perspiration of grade 4-5, a breaking strength of 2.6 cN / dtex, a breaking elongation of 49%, an antibacterial rate of 99.3% against Escherichia coli, and an antibacterial rate of 99.6% against Staphylococcus aureus.

[0109] Example 4 Reference Figures 6-9 A method for dyeing wool fibers, comprising the following steps: (1) Preparation of ionic liquids: SO2F2, 1-methylimidazolium-2-thiol, 1-propanethiol, triethylamine, and acetonitrile were reacted at a molar ratio of 0.25:1:2.1:18:400 at 46 °C for 33 h to give compound X. The structural formula of compound X is [insert structural formula here]. Compound X, CH3Br, and p-xylene were added to a three-necked flask in a molar ratio of 1:1.18:400 and reacted at 83°C for 4.5 h under nitrogen protection. The product was extracted with ethyl acetate, and the lower viscous layer was distilled and then dried at 76°C for 17 h to obtain an ionic liquid with the following structural formula: .

[0110] (2) Staining with ionic liquids: Natural indigo was dissolved in an ionic liquid with a pH of 4.3 to form a dye solution. Wool fiber raw materials were then completely immersed in the dye solution and dyed at a constant temperature of 57°C for 27 minutes. After dyeing, the wool fiber raw materials were washed four times with ethanol and then vacuum dried at 67°C for 80 minutes to obtain wool fibers. The mass ratio of wool fiber, bio-derived dye, and ionic liquid was 1:0.25:110. The recovery rate of the ionic liquid was 96.9%.

[0111] The final wool fiber has a K / S value of 5.3, a color difference ΔE of 0.19, a dyeing rate of 78%, and color fastness to sunlight, soaping, dry rubbing, and perspiration of grade 4-5. Its breaking strength is 2.7 cN / dtex, its breaking elongation is 51%, and its antibacterial rate against Escherichia coli is 99.4%, while its antibacterial rate against Staphylococcus aureus is 99.6%.

[0112] Example 5 A method for dyeing wool fibers, comprising the following steps: (1) Preparation of ionic liquids: SO2F2, 1-methylimidazol-2-thiol, 1-propanethiol, triethylamine, and acetonitrile were reacted at a molar ratio of 0.3:1:2.3:20:500 at 50°C for 36 h to give compound X. The structural formula of compound X is [insert structural formula here]. Compound X, CH3Br, and o-xylene were added to a three-necked flask in a molar ratio of 1:1.2:500 and reacted at 85°C for 5 h under helium protection. The product was extracted with ethyl acetate, and the lower viscous layer was distilled and then dried at 78°C for 18 h to obtain an ionic liquid with the following structural formula: .

[0113] (2) Staining with ionic liquids: Carmine was dissolved in an ionic liquid with a pH of 4.5 to form a dye solution. Wool fiber raw material was then completely immersed in the dye solution and dyed at a constant temperature of 60℃ for 30 minutes. After dyeing, the wool fiber raw material was washed four times with ethanol and then vacuum dried at 70℃ for 90 minutes to obtain wool fiber. The mass ratio of wool fiber, bio-derived dye, and ionic liquid was 1:0.3:130. The recovery rate of the ionic liquid was 97.5%.

[0114] The final wool fiber has a K / S value of 5.6, a color difference ΔE of 0.25, a dyeing rate of 80%, and color fastness to sunlight, soaping, dry rubbing, and perspiration of grade 4-5. Its breaking strength is 2.8 cN / dtex, its breaking elongation is 53%, and it exhibits an antibacterial rate of 99.5% against Escherichia coli and 99.7% against Staphylococcus aureus.

[0115] Example 6 A method for dyeing wool fibers, comprising the following steps: (1) Preparation of ionic liquids: SO2F2, 1-methylimidazol-2-thiol, 1-propanethiol, triethylamine, and acetonitrile were reacted at a molar ratio of 0.35:1:2.5:22:600 at 52 °C for 39 h to give compound X. The structural formula of compound X is [insert structural formula here]. Compound X, CH3Br, and mesitylene were added to a three-necked flask in a molar ratio of 1:1.22:600 and reacted at 86°C for 5 h under argon protection. The product was extracted with ethyl acetate, and the lower viscous layer was distilled and then dried at 80°C for 19 h to obtain an ionic liquid with the following structural formula: .

[0116] (2) Staining with ionic liquids: Epicatechin was dissolved in an ionic liquid with a pH of 4.6 to form a dye solution. Wool fiber raw materials were then completely immersed in the dye solution and dyed at a constant temperature of 62℃ for 32 minutes. The dyed wool fiber raw materials were washed five times with ethanol and then vacuum dried at 73℃ for 100 minutes to obtain wool fibers. The mass ratio of wool fiber, bio-derived dye, and ionic liquid was 1:0.35:150. The recovery rate of the ionic liquid was 98.6%.

[0117] The final wool fiber has a K / S value of 5.9, a color difference ΔE of 0.31, a dyeing rate of 82%, a color fastness to sunlight of grade 4-5, a color fastness to soaping of grade 4-5, a color fastness to dry rubbing of grade 5, a color fastness to perspiration of grade 5, a breaking strength of 2.9 cN / dtex, a breaking elongation of 55%, an antibacterial rate of 99.6% against Escherichia coli, and an antibacterial rate of 99.7% against Staphylococcus aureus.

[0118] Example 7 Reference Figures 10-13 A method for dyeing wool fibers, comprising the following steps: (1) Preparation of ionic liquids: SO2F2, 1-methylimidazol-2-thiol, 1-butanethiol, triethylamine, and acetonitrile were reacted at a molar ratio of 0.4:1:2.7:25:700 at 54 °C for 42 h to give compound X. The structural formula of compound X is [insert structural formula here]. Compound X, CH3Br, and mesitylene were added to a three-necked flask in a molar ratio of 1:1.25:800 and reacted at 87°C for 5.5 h under nitrogen protection. The product was extracted with propyl acetate, and the lower viscous layer was distilled and then dried at 81°C for 20 h to obtain an ionic liquid with the following structural formula: .

[0119] (2) Staining with ionic liquids: Tannic acid was dissolved in an ionic liquid with a pH of 4.7 to form a dye solution. Wool fiber raw materials were then completely immersed in the dye solution and dyed at a constant temperature of 65°C for 35 minutes. The dyed wool fiber raw materials were washed three times with ethanol and then vacuum dried at 75°C for 110 minutes to obtain wool fibers. The mass ratio of wool fiber, bio-derived dye, and ionic liquid was 1:0.4:170. The recovery rate of the ionic liquid was 99.1%.

[0120] The final wool fiber has a K / S value of 6.2, a color difference ΔE of 0.36, a dyeing rate of 85%, and color fastness to sunlight, soaping, dry rubbing, and perspiration of grade 5. Its breaking strength is 3 cN / dtex, its breaking elongation is 57%, and its antibacterial rate against Escherichia coli is 99.6% and against Staphylococcus aureus is 99.8%.

[0121] Example 8 A method for dyeing wool fibers, comprising the following steps: (1) Preparation of ionic liquids: SO2F2, 1-methylimidazol-2-thiol, 1-butanethiol, triethylamine, and acetonitrile were reacted at a molar ratio of 0.45:1:2.8:28:850 at 58°C for 45 h to obtain compound X. The structural formula of compound X is [insert structural formula here]. Compound X, CH3Br, and p-xylene were added to a three-necked flask in a molar ratio of 1:1.27:900 and reacted at 89°C for 6 h under helium protection. The product was extracted with propyl acetate, and the lower viscous layer was distilled and then dried at 83°C for 22 h to obtain an ionic liquid with the following structural formula: .

[0122] (2) Staining with ionic liquids: Natural indigo was dissolved in an ionic liquid with a pH of 4.9 to form a dye solution. Wool fiber raw materials were then completely immersed in the dye solution and dyed at a constant temperature of 68℃ for 38 minutes. After dyeing, the wool fiber raw materials were washed four times with ethanol and then vacuum dried at 78℃ for 115 minutes to obtain wool fibers. The mass ratio of wool fiber, bio-derived dye, and ionic liquid was 1:0.45:190. The recovery rate of the ionic liquid was 99.3%.

[0123] The final wool fiber has a K / S value of 6.5, a color difference ΔE of 0.41, a dyeing rate of 88%, and color fastness to sunlight, soaping, dry rubbing, and perspiration of grade 5. Its breaking strength is 3.1 cN / dtex, its breaking elongation is 58%, and its antibacterial rate against Escherichia coli is 99.7% and against Staphylococcus aureus is 99.9%.

[0124] Example 9 A method for dyeing wool fibers, comprising the following steps: (1) Preparation of ionic liquids: SO2F2, 1-methylimidazol-2-thiol, 1-butanethiol, triethylamine, and acetonitrile were reacted at a molar ratio of 0.5:1:3:30:1000 at 50°C for 48 h to give compound X. The structural formula of compound X is [insert structural formula here]. Compound X, CH3Br, and toluene were added to a three-necked flask in a molar ratio of 1:1.3:1000 and reacted at 90°C for 6 h under argon protection. The product was extracted with propyl acetate, and the lower viscous layer was distilled and then dried at 85°C for 24 h to obtain an ionic liquid with the following structural formula: .

[0125] (2) Staining with ionic liquids: Tannic acid was dissolved in an ionic liquid with a pH of 5 to form a dye solution. Wool fiber raw materials were then completely immersed in the dye solution and dyed at a constant temperature of 70°C for 40 minutes. After dyeing, the wool fiber raw materials were washed five times with ethanol and then vacuum-dried at 80°C for 120 minutes to obtain wool fibers. The mass ratio of wool fiber, bio-derived dye, and ionic liquid was 1:0.5:200. The recovery rate of the ionic liquid was 99.5%.

[0126] The final wool fiber has a K / S value of 6.7, a color difference ΔE of 0.5, a dyeing rate of 90%, a color fastness grade of 5 for light exposure, a color fastness grade of 5 for washing with soap, a color fastness grade of 5 for dry rubbing, a color fastness grade of 5 for perspiration, a breaking strength of 3.2 cN / dtex, a breaking elongation of 60%, an antibacterial rate of 99.7% against Escherichia coli, and an antibacterial rate of 99.9% against Staphylococcus aureus.

[0127] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein. The scope of this disclosure is defined by the appended claims.

Claims

1. A method of dyeing wool fibers, characterized by, The staining method includes the following steps: S1, preparing an ionic liquid: mixing compound X, CH3Br, and an aromatic hydrocarbon solvent according to a first preset molar ratio, reacting under inert gas protection at a first preset temperature for a first preset time, extracting the product after reaction with an extracting agent, distilling the lower mucilage after extraction, and then drying at a second preset temperature for a second preset time to obtain an ionic liquid, wherein the structural formula of the compound X is , R1 is ethyl, n-propyl, or n-butyl; S2. Ionic liquid dyeing: Dissolve the bio-derived dye in an ionic liquid to form a dye solution; then completely immerse the wool fiber raw material in the dye solution and dye it at a third preset temperature for a third preset time. After dyeing, the wool fiber raw material is washed with ethanol a preset number of times and then vacuum dried at a fourth preset temperature for a fourth preset time to obtain wool fiber.

2. The method for dyeing wool fibers according to claim 1, characterized in that, The inert gas is one of nitrogen, helium, or argon; The aromatic hydrocarbon solvent is one of toluene, p-xylene, m-xylene, o-xylene, and mesitylene; The extractant is one of methyl acetate, ethyl acetate, or propyl acetate.

3. The method for dyeing wool fibers according to claim 2, characterized in that, The first preset molar ratio of compound X, CH3Br, and aromatic hydrocarbon solvent is 1:1.1-1.3:100-1000.

4. The method for dyeing wool fibers according to claim 3, characterized in that, Compound X is obtained by reacting SO2F2, 1-methylimidazol-2-thiol, thiol Y, triethylamine, and acetonitrile at a second preset molar ratio and a fifth preset temperature, wherein the thiol Y is one of ethanethiol, 1-propanethiol, and 1-butanethiol.

5. The dyeing method for wool fibers according to claim 4, characterized in that, The second preset molar ratio of SO2F2, 1-methylimidazol-2-thiol, thiol Y, triethylamine, and acetonitrile is 0.1-0.5:1:1.5-3:10-30:100-1000.

6. The method for dyeing wool fibers according to claim 5, characterized in that, The fifth preset temperature is 40-60℃.

7. The method for dyeing wool fibers according to claim 6, characterized in that, The first preset temperature is 80-90℃, and the first preset duration is 3-6h.

8. The method for dyeing wool fibers according to claim 7, characterized in that, The second preset temperature is 70-85℃, and the second preset duration is 12-24h.

9. A method for dyeing wool fibers according to claim 8, characterized in that, The recovery rate of the ionic liquid is 95.5%-99.5%.

10. A method for dyeing wool fibers according to claim 9, characterized in that, The mass ratio of the wool fiber raw material, the bio-derived dye, and the ionic liquid is 1:0.1-0.5:50-200.

11. The method for dyeing wool fibers according to claim 10, characterized in that, The bio-derived dye is one of naringenin, epicatechin, natural indigo, carmine, or tannic acid.

12. The method for dyeing wool fibers according to claim 11, characterized in that, The third preset temperature is 50-70℃, and the third preset duration is 20-40min.

13. The method for dyeing wool fibers according to claim 12, characterized in that, The pH value of the ionic liquid is 4-5.

14. The method for dyeing wool fibers according to claim 13, characterized in that, The preset number of ethanol washes is 3-5 times.

15. A method for dyeing wool fibers according to claim 14, characterized in that, The fourth preset temperature is 60~80℃, and the fourth preset duration is 60~120min.

16. A wool fiber, characterized in that, The wool fiber is obtained by the dyeing method of wool fiber according to any one of claims 1-15.

17. A method for preparing an ionic liquid, characterized in that, include: Compound X, CH3Br, and an aromatic hydrocarbon solvent are mixed in a first preset molar ratio and reacted at a first preset temperature for a first preset time under an inert gas atmosphere. The reaction product is extracted with an extractant, and the lower viscous layer after extraction is distilled and then dried at a second preset temperature for a second preset time to obtain an ionic liquid. The structural formula of compound X is as follows: R1 is ethyl, n-propyl, or n-butyl.

18. The method for preparing an ionic liquid according to claim 17, characterized in that, The inert gas is one of nitrogen, helium, or argon; The aromatic hydrocarbon solvent is one of toluene, p-xylene, m-xylene, o-xylene, and mesitylene; The extractant is one of methyl acetate, ethyl acetate, or propyl acetate.

19. A method for preparing an ionic liquid according to claim 18, characterized in that, The first preset molar ratio of compound X, CH3Br, and aromatic hydrocarbon solvent is 1:1.1-1.3:100-1000.

20. A method for preparing an ionic liquid according to claim 19, characterized in that, Compound X is obtained by reacting SO2F2, 1-methylimidazol-2-thiol, thiol Y, triethylamine, and acetonitrile at a second preset molar ratio and a fifth preset temperature, wherein the thiol Y is one of ethanethiol, 1-propanethiol, and 1-butanethiol.

21. The method for preparing an ionic liquid according to claim 20, characterized in that, The second preset molar ratio of SO2F2, 1-methylimidazol-2-thiol, thiol Y, triethylamine, and acetonitrile is 0.1-0.5:1:1.5-3:10-30:100-1000.

22. The method for preparing an ionic liquid according to claim 21, characterized in that, The fifth preset temperature is 40-60℃.

23. The method for preparing an ionic liquid according to claim 22, characterized in that, The first preset temperature is 80-90℃, and the first preset duration is 3-6h.

24. The method for preparing an ionic liquid according to claim 23, characterized in that, The second preset temperature is 70-85℃, and the second preset duration is 12-24h.

25. An ionic liquid, characterized in that, The ionic liquid is prepared by the method for preparing the ionic liquid according to any one of claims 17-24.

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