A kind of wormwood pigment dye solution and its preparation method and application

Abstract

The invention relates to the technical field of dye production, and in particular to a wormwood pigment dye solution and a preparation method and application thereof, comprising the following steps: washing, drying, crushing and sieving wormwood to obtain wormwood powder; adding the wormwood powder to a low eutectic solvent containing a hydrogen bond acceptor and a hydrogen bond donor to obtain a mixed solution, wherein the hydrogen bond acceptor is choline chloride, and the hydrogen bond donor is lactic acid or oxalic acid; stirring the mixed solution in a water bath, and then centrifuging it, taking a supernatant to obtain a wormwood pigment dye solution. The invention adopts a low eutectic solvent that is non-toxic and harmless and has a simple preparation method, and can directly prepare the wormwood pigment dye solution by a one-bath method, thereby realizing simultaneous extraction of wormwood pigment and preparation of wormwood dye solution.

Description

Technical Field

[0001] The invention relates to the technical field of dye production, and in particular to a wormwood pigment dye solution and a preparation method and application thereof. Background Art

[0002] Wormwood pigments are rich in volatile oils, ketones, glycosides and sugar chemical components, and have antibacterial, insect-resistant, antioxidant, and UV-resistant functions. Extracting wormwood functional pigments and directly using them for dyeing can give yarns or fabrics a natural luster while realizing their multifunctionality, which meets the high-end needs of today's market. Existing methods for extracting wormwood pigment dyes are still based on traditional physical methods such as immersion, percolation, decoction reflux extraction and continuous reflux extraction, or chemical extraction methods such as methanol, ethanol, acetone, oil or alkaline aqueous solution, and corresponding auxiliaries are used when dyeing fabrics to improve the color yield of the fabrics; however, the existing extraction methods have problems such as insufficient extraction of effective pigment components, low color yield, and the generation of chemical waste liquid in the extraction process, which causes certain waste and damage to resources and the environment. Summary of the invention

[0003] In view of the deficiencies of the above-mentioned prior art, the object of the present invention is to provide a wormwood pigment dye solution and a preparation method and application thereof. The present invention adopts a low eutectic solvent which is non-toxic and harmless and has a simple preparation method. It can be directly prepared into wormwood pigment dye solution by a one-bath method, thereby realizing the simultaneous extraction of wormwood pigment and preparation of wormwood dye solution.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A method for preparing a wormwood pigment dye solution comprises the following steps:

[0006] The mugwort is washed, dried, crushed and sieved to obtain mugwort powder.

[0007] The wormwood powder is mixed with a low eutectic solvent containing a hydrogen bond acceptor and a hydrogen bond donor to obtain a mixed solution, wherein the hydrogen bond acceptor is choline chloride and the hydrogen bond donor is lactic acid or oxalic acid.

[0008] The mixed solution is stirred in a water bath, and then centrifuged to obtain the supernatant to obtain the wormwood pigment dye solution.

[0009] The present invention mixes wormwood powder with a low eutectic solvent containing a hydrogen bond acceptor and a hydrogen bond donor, wherein the hydrogen bond acceptor is choline chloride, and the hydrogen bond donor is lactic acid or oxalic acid. Through a one-bath method experiment, wormwood pigment and its own volatile oil, flavonoids and other beneficial chemical components are successfully extracted and retained, and a high-concentration anhydrous wormwood pigment dye solution in a low eutectic solvent bath is also directly prepared. Wormwood contains functional components such as polyphenols and flavonoids. The flavonoid molecules contain functional groups such as hydroxycarbonyl, which can hydrogen bond with the hydrogen bond donors lactic acid or oxalic acid in the low eutectic solvent, so that efficient extraction can be achieved. The invention is an environmentally friendly and novel method for preparing plant pigment dye solution.

[0010] In a preferred embodiment of the present invention, the volume ratio of the mass of the wormwood powder to the low eutectic solvent is 1 g:10 mL~30 mL.

[0011] In a preferred embodiment of the present invention, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor in the deep eutectic solvent is 1:1.

[0012] In a preferred embodiment of the present invention, the water bath temperature is 60° C. to 80° C., and the stirring time is 60 min to 90 min.

[0013] In a preferred embodiment of the present invention, the centrifugal speed is 2500 rpm to 3500 rpm, and the centrifugal time is 8 min to 12 min.

[0014] In a preferred embodiment of the present invention, the mesh size of the sieve after crushing is 30-50 mesh.

[0015] In a preferred embodiment of the present invention, a method for preparing a low eutectic solvent containing a hydrogen bond acceptor and a hydrogen bond donor comprises the following steps: the hydrogen bond acceptor and the hydrogen bond donor are mixed at 90°C to 110°C to obtain a transparent, clear, viscous liquid, and the mixed low eutectic solvent can maintain a stable liquid state at room temperature, has a low melting point, and may crystallize again when the room temperature is below 10°C. It can be restored to a liquid state by continuing to heat at 20°C and can be reused.

[0016] Another object of the present invention is to provide a wormwood pigment dye solution prepared by any of the preparation methods described above.

[0017] The third object of the present invention is to provide an application of the above-mentioned wormwood pigment dye solution in cotton fabric dyeing.

[0018] Deep eutectic solvent, abbreviated as DES, is a degradable ionic solvent with the advantages of strong structural design, convenient synthesis, low cost, and strong biocompatibility. It has been proven to be applicable to nanomaterial synthesis, material surface modification, organic synthesis, biomass catalysis, extraction, purification, etc. In the future, it will have great application prospects in many fields such as clothing, medicine, skin care cosmetics and even food.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention mixes wormwood powder with a low eutectic solvent containing a hydrogen bond acceptor and a hydrogen bond donor, wherein the hydrogen bond acceptor is choline chloride, and the hydrogen bond donor is lactic acid or oxalic acid. Through a one-bath experiment, the wormwood pigment and its own volatile oil, flavonoids and other beneficial chemical components are successfully extracted and retained, and a high-concentration anhydrous wormwood pigment dye solution in a low eutectic solvent bath is directly prepared. Wormwood contains functional components such as polyphenols and flavonoids. The flavonoid molecules contain functional groups such as hydroxycarbonyl, which can hydrogen bond with the hydrogen bond donors lactic acid or oxalic acid in the low eutectic solvent, thereby achieving efficient extraction. The invention is an environmentally friendly and novel method for preparing plant pigment dye solution.

[0021] 2. The high-concentration anhydrous wormwood pigment dye solution in the low eutectic solvent bath prepared by the present invention has the following advantages: single-line short process and simple preparation process; the low eutectic solvent choline chloride itself has certain antibacterial properties, and the fabric dyed with the dye solution has better antibacterial properties; the finished dye solution is anhydrous, easier to preserve, highly stable, and reusable; the prepared wormwood dye solution has a high concentration and can be mixed with a certain concentration of pure water to prepare wormwood liquid dye solutions of different concentrations; the low eutectic solvent in the wormwood dye solution has the effect of micro-etching the fiber. Compared with other commercially available wormwood dyes, the fabric or fiber dyed with the dye solution of the present invention has a better color yield.

[0022] 3. In recent years, the market demand for natural functional colored yarn and its textiles has been rising year by year, such as antibacterial, mosquito repellent, anti-ultraviolet, etc. The products have high added value and have attracted widespread attention from the business community. However, the processing of functional colored yarn and textiles still needs to rely on the effect of chemical finishing agents, and it is impossible to be purely natural. The residue and migration of chemical agents pose certain hidden dangers to the users, and the processing of functional colored yarn also causes certain damage to the natural environment. The present invention will effectively fill the gap in the efficient extraction of natural pigments; the use of the dye solution will realize the gap in the full-line short-process dyeing production technology. Direct dyeing of pigments does not require the addition and residue of chemical agents, and can be used in medical textiles, infant clothing, high-end home textile products, outdoor clothing and other fields, and the demand is large. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The UV-visible spectra of wormwood pigments extracted by different systems of the present invention are shown.

[0024] Figure 2 These are the experimental results of dyeing cotton fabrics with the wormwood pigment dye solutions prepared in Example 1 and Comparative Examples 4-5 of the present invention.

[0025] Figure 3 This is the infrared spectrum of the wormwood pigment extracted by different system solutions of the present invention. DETAILED DESCRIPTION

[0026] The following is a detailed description of the technical solutions in the embodiments of the present invention in combination with the preferred embodiments and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that all professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0028] Example 1

[0029] A method for preparing a wormwood pigment dye solution comprises the following steps:

[0030] (1) Wash the commercially available dried mugwort leaves, remove the surface sediment, and place them in a drying oven to dry until constant weight. Grind the mugwort in a food processor, pass through a 40-mesh sieve, and store in a sealed glass bottle for later use.

[0031] (2) Choline chloride and oxalic acid are mixed at a molar ratio of 1:1 at 100° C. to obtain a transparent, clear, viscous liquid, i.e., a choline chloride / oxalic acid low eutectic solvent.

[0032] (3) 1 g of wormwood powder was placed in the choline chloride / oxalic acid low eutectic solvent, wherein the solid-liquid ratio was 1 g:10.6 mL. After stirring in a 79.3°C magnetic stirring water bath for 82.5 min, the solution was placed in a centrifuge and centrifuged at 3000 rpm for 10 min. The supernatant was taken to finally obtain the wormwood pigment dye solution.

[0033] Example 2

[0034] A method for preparing a wormwood pigment dye solution comprises the following steps:

[0035] (1) Wash the commercially available dried mugwort leaves, remove the surface sediment, and place them in a drying oven to dry until constant weight. Grind the mugwort in a food processor, pass through a 40-mesh sieve, and store in a sealed glass bottle for later use.

[0036] (2) Choline chloride and lactic acid are mixed at a molar ratio of 1:1 at 100° C. to obtain a transparent, clear, viscous liquid, i.e., a choline chloride / lactic acid low eutectic solvent.

[0037] (3) 1 g of wormwood powder was placed in the choline chloride / lactic acid low eutectic solvent, wherein the solid-liquid ratio was 1 g:10.6 mL. After stirring in a 79.3°C magnetic stirring water bath for 82.5 min, the solution was placed in a centrifuge and centrifuged at 3000 rpm for 10 min. The supernatant was taken to obtain the wormwood pigment dye solution.

[0038] Example 3

[0039] A method for preparing a wormwood pigment dye solution comprises the following steps:

[0040] (1) Wash the commercially available dried mugwort leaves, remove the surface sediment, and place them in a drying oven to dry to constant weight. Grind the mugwort in a food processor, pass through a 30-mesh sieve, and store in a sealed glass bottle for later use.

[0041] (2) Choline chloride and oxalic acid are mixed at a molar ratio of 1:1 at 90° C. to obtain a transparent, clear, viscous liquid, i.e., a choline chloride / oxalic acid low eutectic solvent.

[0042] (3) 1 g of wormwood powder was placed in the choline chloride / oxalic acid low eutectic solvent, wherein the solid-liquid ratio was 1 g:10 mL. After stirring in a 60°C magnetic stirring water bath for 90 min, the solution was placed in a centrifuge and centrifuged at 2500 rpm for 12 min. The supernatant was taken to obtain the wormwood pigment dye solution.

[0043] Example 4

[0044] A method for preparing a wormwood pigment dye solution comprises the following steps:

[0045] (1) Wash the commercially available dried mugwort leaves, remove the surface sediment, and place them in a drying oven to dry to constant weight. Grind the mugwort in a food processor, pass through a 50-mesh sieve, and store in a sealed glass bottle for later use.

[0046] (2) Choline chloride and oxalic acid are mixed at a molar ratio of 1:1 at 110° C. to obtain a transparent, clear, viscous liquid, i.e., a choline chloride / oxalic acid low eutectic solvent.

[0047] (3) 1 g of wormwood powder was placed in the choline chloride / oxalic acid low eutectic solvent, wherein the solid-liquid ratio was 1 g:30 mL. After stirring in a magnetic stirring water bath at 80°C for 60 min, the solution was placed in a centrifuge and centrifuged at 3500 rpm for 8 min. The supernatant was taken to finally obtain the wormwood pigment dye solution.

[0048] Comparative Example 1

[0049] A method for preparing a wormwood pigment dye solution comprises the following steps:

[0050] (1) Wash the commercially available dried mugwort leaves, remove the surface sediment, and place them in a drying oven to dry until constant weight. Grind the mugwort in a food processor, pass through a 40-mesh sieve, and store in a sealed glass bottle for later use.

[0051] (2) Choline chloride and urea are mixed at a molar ratio of 1:1 at 100° C. to obtain a transparent, clear, viscous liquid, i.e., a choline chloride / urea low eutectic solvent.

[0052] (3) 1 g of wormwood powder was placed in the choline chloride / urea low eutectic solvent, wherein the solid-liquid ratio was 1:10.6, and the solution was stirred in a magnetic stirring water bath at 79.3°C for 82.5 min. The solution was placed in a centrifuge and centrifuged at 3000 rpm for 10 min. The supernatant was taken to obtain the wormwood pigment dye solution.

[0053] Comparative Example 2

[0054] A method for preparing a wormwood pigment dye solution comprises the following steps:

[0055] (1) Wash the commercially available dried mugwort leaves, remove the surface sediment, and place them in a drying oven to dry until constant weight. Grind the mugwort in a food processor, pass through a 40-mesh sieve, and store in a sealed glass bottle for later use.

[0056] (2) Choline chloride and 1,4-butanediol are mixed at a molar ratio of 1:1 at 100° C. to obtain a transparent, clear, viscous liquid, i.e., a choline chloride / 1,4-butanediol low eutectic solvent.

[0057] (3) Take 1 g of mugwort powder and place it in a choline chloride / 1,4-butanediol low eutectic solvent with a molar ratio of 1:1, where the solid-liquid ratio is 1:10.6. After stirring in a magnetic stirring water bath at 79.3°C for 82.5 min, place the solution in a centrifuge and centrifuge at 3000 rpm for 10 min. Take the supernatant and finally obtain the mugwort pigment dye solution.

[0058] Comparative Example 3

[0059] A method for preparing a wormwood pigment dye solution comprises the following steps:

[0060] (1) Wash the commercially available dried mugwort leaves, remove the surface sediment, and place them in a drying oven to dry until constant weight. Grind the mugwort in a food processor, pass through a 40-mesh sieve, and store in a sealed glass bottle for later use.

[0061] (2) Choline chloride and ethylene glycol are mixed at a molar ratio of 1:1 at 100° C. to obtain a transparent, clear, viscous liquid, i.e., a choline chloride / ethylene glycol low eutectic solvent.

[0062] (3) Take 1 g of mugwort powder and place it in a choline chloride / ethylene glycol low eutectic solvent with a molar ratio of 1:1, where the solid-liquid ratio is 1:10.6. After stirring in a magnetic stirring water bath at 79.3°C for 82.5 min, place the solution in a centrifuge and centrifuge at 3000 rpm for 10 min. Take the supernatant and finally obtain the mugwort pigment dye solution.

[0063] Comparative Example 4

[0064] A method for preparing a wormwood pigment dye solution comprises the following steps:

[0065] (1) Wash the commercially available dried mugwort leaves, remove the surface sediment, and place them in a drying oven to dry until constant weight. Grind the mugwort in a food processor, pass through a 40-mesh sieve, and store in a sealed glass bottle for later use.

[0066] (2) Take 1 g of mugwort powder and place it in pure water, where the solid-liquid ratio is 1:10.6. After stirring in a magnetic stirring water bath at 79.3℃ for 82.5 min, place the solution in a centrifuge and centrifuge at 3000 rpm for 10 min. Take the supernatant and finally obtain the mugwort pigment dye solution.

[0067] Comparative Example 5

[0068] A method for preparing a wormwood pigment dye solution comprises the following steps:

[0069] (1) Wash the commercially available dried mugwort leaves, remove the surface sediment, and place them in a drying oven to dry until constant weight. Grind the mugwort in a food processor, pass through a 40-mesh sieve, and store in a sealed glass bottle for later use.

[0070] (2) Take 1 g of mugwort powder and place it in ethanol with a solid-liquid ratio of 1:10.6. After stirring in a magnetic stirring water bath at 79.3°C for 82.5 min, place the solution in a centrifuge and centrifuge at 3000 rpm for 10 min. Take the supernatant and finally obtain the mugwort pigment dye solution.

[0071] Results Analysis

[0072] Five groups of typical low eutectic solvent systems with different pH values ​​were selected, and the pigment extraction experiment of wormwood powder was carried out under the same experimental parameter conditions. The reaction temperature was 60 °C, the solid-liquid ratio was 1:20, and the reaction time was 40 min. Ethanol and pure water were set as control groups. The absorbance values ​​are shown in Table 1. Choline chloride, abbreviated as ChCl, urea, abbreviated as urea, 1,4-butanediol, abbreviated as 1,4-BDO, ethylene glycol, abbreviated as EG, lactic acid, abbreviated as LAC, oxalic acid, abbreviated as OA.

[0073] Table 1 Absorbance values ​​of wormwood pigment extracts in various systems

[0074]

[0075] The experiment compared five deep eutectic solvents and two control groups of wormwood pigment extraction solutions, such as Figure 1 As shown in the figure, it was found that the wormwood pigment extracted by the choline chloride / oxalic acid system not only had a high absorbance value, but also had no significant shift at the wavelength of 660 nm. The systems of various low eutectic solvents were similar, but there were differences in acidity and alkalinity and the number of oxygen-containing functional groups. The number of oxygen-containing groups determined the hydrogen bonding and series of reactions with polyphenols, flavonoids and other components in wormwood, which affected the extraction rate of wormwood pigment. In summary, it can be confirmed that the low eutectic solvent of the choline chloride / oxalic acid system is the optimal system for extracting wormwood pigment.

[0076] Then, the response surface experiment was carried out using the response surface experimental design software Design-Expert 13. The experimental conditions shown in Tables 2 and 3 were designed and tested one by one. The absorbance value results obtained by the Box-Behnken experimental design of the response surface method were analyzed in series, and SPSS 25 was used for significant difference analysis. P < 0.05 indicated a statistically significant difference, P < 0.05 indicated a significant difference, and P < 0.01 indicated an extremely significant difference. The relevant data were analyzed and processed.

[0077] Table 2 Response surface methodology Box-Behnken experimental design and results

[0078]

[0079] Table 3 Analysis of variance results of Box-Behnken experimental design using response surface methodology

[0080]

[0081] Note: P<0.05 significant difference; When P<0.01, the difference is particularly significant. The F value indicates the F distribution; the P value indicates whether there is a significant difference.

[0082] Finally, the optimal one-bath extraction process of DES for wormwood pigments was determined as follows: wash the commercially available dried wormwood leaves, remove the surface sediments, and place them in a drying oven to dry to constant weight; grind the wormwood with a food processor, pass through a 40-mesh sieve, and store in a sealed glass bottle for later use. Take 1 g of wormwood powder and place it in ChCl / OA DES with a solid-liquid ratio of 1 g:10.6 mL. After stirring in a 79.3℃ magnetic stirring water bath for 82.5 min, place the solution in a centrifuge and centrifuge at 3000 rpm for 10 min. Take the supernatant and finally obtain wormwood pigment@DES liquid dye.

[0083] Figure 2 The dyeing experiment results of cotton fabrics prepared by the wormwood pigment dye solution of Example 1 and Comparative Examples 4-5 of the present invention are shown in FIG. Figure 2 As shown, the cotton cloth dyed with the wormwood liquid dye prepared by extraction with choline chloride / oxalic acid system has the highest color yield and the darkest color.

[0084] The dyeing principle of wormwood dye liquor in the present invention is mainly that small dye molecules are first absorbed and then diffused into a dynamic process inside the fiber on the fiber surface, which is related to the temperature and time of dyeing. Wherein, the optimal dyeing temperature is related to the melting point of the fiber itself, so it is not that the higher the temperature, the better the dyeing effect. Under the most suitable dyeing temperature, the fiber's own molecular chain motion intensifies, and the aperture is opened. The dye molecules are more easily dyed to the inside of the polylactic acid fiber under the effect of the concentration difference, and on the basis of ensuring the dyeing effect, finding a lower dyeing temperature is to improve experimental safety, and the second is to play an energy-saving effect. Fiber is dyed at a higher temperature, and the time is too long to increase the experimental time on the one hand, if applied to an enterprise to increase time and money cost, on the other hand, a certain degree of structural damage will be caused to the fiber itself, affecting the mechanical properties of the fiber, so the shorter the dyeing time is, the better on the basis of ensuring the dyeing effect.

[0085] The water bath temperature, stirring time, rotation speed and centrifugation time in the process of preparing the dye solution affect the quality of the final dye solution to a certain extent. Factors such as temperature and stirring time will determine whether the molecules of wormwood powder and low eutectic solvent are dispersed more evenly in the solvent, the smaller the molecules are, and the more helpful it is to improve the dyeing effect.

[0086] The dyeing temperature was set to 70℃ and the dyeing time was set to 50 min. Three wormwood liquid dyes prepared in the same preparation method and different systems were used to dye cotton fabrics. It was found that the color yield of cotton fabrics dyed with liquid dyes prepared by the ChCl / OA DES system was significantly higher than that of liquid dyes prepared by other systems, and the fabrics were dyed more evenly. Then, the test was carried out according to the national standard GB / T3920-2008 dry and wet friction color fastness test requirements. As shown in Table 4, the dry and wet color fastness of the fabrics dyed with the homemade dye solution also met the national standard requirements, and the dyeing quality was high.

[0087] Table 4 Dry and wet rubbing color fastness of fabrics dyed with the dye liquor of the present invention

[0088]

[0089] The infrared spectra of wormwood pigment extracted by different system solutions are shown in Figure 3 As shown, several extracts all showed C=C stretching vibration of terpenoid compounds in the range of 2900. The extracts except the pure water system all had CC=O stretching vibration at 515 and ester characteristic peak at 1080. At 1600, only the ChCl / OA system and the wormwood pigment extracted by pure water had absorption characteristic peaks, which were the main flavonoids and alcohols of wormwood. In summary, it was shown that the wormwood pigment extracted by the ChCl / OA system still retained the alcohol, esters and flavonoids in wormwood and was evenly mixed.

[0090] In summary, the present invention mixes a low eutectic solvent with wormwood pigment, and through a one-bath method experiment, successfully extracts and retains wormwood pigment and its own volatile oil, flavonoids and other beneficial chemical components, and directly prepares a high-concentration anhydrous wormwood pigment dye solution of a low eutectic solvent bath, which is an environmentally friendly, novel method for preparing a plant pigment dye solution. The high-concentration anhydrous wormwood pigment dye solution of the prepared low eutectic solvent bath has the following advantages: single-line short process, simple preparation process; the low eutectic solvent choline chloride itself has certain antibacterial properties, and the fabric dyed with the dye solution has better antibacterial properties; the finished dye solution is anhydrous, easier to store and has high stability, and can be reused; the prepared wormwood dye solution has a high concentration, and can be mixed with a certain concentration of pure water to prepare wormwood liquid dye solutions of different concentrations; the low eutectic solvent in the wormwood dye solution has the effect of micro-etching the fiber, and compared with other commercially available wormwood dyes, the fabric or fiber dyed with the dye solution of the present invention has a better color yield.

[0091] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the attached claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0092] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the protection scope of the present invention and its equivalent technology, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a wormwood pigment dye solution, characterized in that: The following steps are involved: Washing, drying, crushing and sieving the mugwort to obtain mugwort powder; Adding the wormwood powder to a low eutectic solvent containing a hydrogen bond acceptor and a hydrogen bond donor to obtain a mixed solution, wherein the hydrogen bond acceptor is choline chloride and the hydrogen bond donor is lactic acid or oxalic acid; The mixed solution is stirred in a water bath, then centrifuged, the supernatant is taken, and the wormwood pigment dye solution is obtained by a one-bath method, wherein the water bath temperature is 60° C. to 80° C.; The volume ratio of the wormwood powder to the deep eutectic solvent is 1 g: 10 mL to 30 mL; The molar ratio of the hydrogen bond acceptor to the hydrogen bond donor in the deep eutectic solvent is 1:

1.

2. The method for preparing the wormwood pigment dye solution according to claim 1, wherein The stirring time is 60 min~90 min.

3. The method for preparing the wormwood pigment dye solution according to claim 1, wherein The centrifugal speed is 2500 rpm~3500 rpm, and the centrifugal time is 8 min~12 min.

4. The method for preparing the wormwood pigment dye solution according to claim 1, characterized in that: After crushing, the sieve mesh size is 30 mesh to 50 mesh.

5. A wormwood pigment dye solution obtained by the preparation method according to any one of claims 1 to 4.

6. Use of the wormwood pigment dye solution according to claim 5 in dyeing cotton fabrics.

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