A new dyeing method

Abstract

The application discloses a novel dyeing method, and belongs to the field of yarn dyeing. The steps comprise the following: mixing choline chloride and a first portion of glycerol to form a first mixed system, mixing urea and a second portion of glycerol to form a second mixed system, adding curcumin and water to obtain a dyeing solution, dyeing cotton yarn with the dyeing solution, continuously padding the cotton yarn with a nanocellulose solution, and drying to obtain finished dyed yarn. The method forms a hydrogen bond network with choline chloride, glycerol, urea and water, enhances the interaction between molecules, improves the combination rate of curcumin and cotton fibers through the hydrogen bond network, increases the dyeing rate of curcumin on cotton fibers, and does not need to use heavy metal inorganic salts and rare earth elements. In combination with subsequent padding and drying treatment, a layer of nanocellulose film formed on the surface of the cotton yarn protects the yarn and the dye already combined with the cotton fibers, improves the wear resistance of the yarn, reduces subsequent fading, and comprehensively improves the color fastness of the dyed yarn.

Description

Technical Field

[0001] This invention relates to a novel dyeing method, belonging to the field of yarn dyeing. Background Technology

[0002] As times have changed, people's pursuit of denim clothing is no longer limited to blue; black and colored denim are becoming increasingly popular. Colored denim is generally dyed using plant-based dyes.

[0003] During the dyeing process using natural plant dyes, most natural plant dyes have low solubility in the dye bath. This promotes dye aggregation, reduces the binding rate between the dye and the fiber, and results in yarn with low color fastness and a low dyeing K / S value.

[0004] Curcumin is a natural yellow pigment extracted from plants of the genus Curcuma. It is one of the most vibrant traditional natural yellow dyes, but it is almost insoluble in water, resulting in low dye uptake and poor colorfastness when used to dye fibers. This significantly limits the use of this natural pigment in textiles.

[0005] To address the difficulty of curcumin dyeing, existing technologies often incorporate iron and copper compounds as mordants. While this improves the dyeing rate and colorfastness of natural curcumin, it also leaves residual metal compounds in the garments, potentially exceeding safety standards, causing skin allergies, and harming user health. Furthermore, it can lead to quality issues such as color variations during the dyeing process. Some researchers have explored using low-toxicity rare earth salts to replace traditional heavy metal salts as mordants, but these solutions are extremely expensive and not conducive to sustainable development. Therefore, existing technologies require improvement. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides a novel dyeing method that leaves no heavy metal residue and produces yarn with high color fastness.

[0007] The technical solution adopted by this invention to solve its technical problem is: A novel staining method includes the following steps: Choline chloride and the first part of glycerol are mixed to form a first mixture system, and urea and the second part of glycerol are mixed to form a second mixture system; The first mixture, the second mixture, and curcumin are added to a dyeing tank containing water to prepare a dye solution. The cotton yarn is dyed using the dye solution; The dyed cotton yarn is impregnated with a nanocellulose solution and then subjected to a first drying treatment to obtain the finished dyed yarn.

[0008] This application provides a novel dyeing method that constructs a new solution environment by using choline chloride, glycerol, urea, and water to form a hydrogen bond network, enhancing the intermolecular interactions. This hydrogen bond network increases the binding rate of curcumin to cotton fibers, thereby increasing the dye uptake rate of curcumin on cotton fibers. Furthermore, the method utilizes a nanocellulose solution to impregnate cotton yarn, and after drying, forms a film on the surface of the cotton yarn to bind curcumin, protecting the dye already bound to the cotton fibers. This comprehensively improves the color fastness of the dyed yarn.

[0009] Further, the step of mixing choline chloride and the first portion of glycerol to form a first mixture includes: Weigh out the choline chloride and the first part of glycerol in a mass ratio of 1:1, and mix them at 75°C with a stirring speed of 800 r / min to 1000 r / min to obtain the first mixed system. The step of mixing urea and the second part of glycerol to form a second mixture includes: Weigh out the urea and the second part of glycerol in a mass ratio of 1:1, and mix them at 75°C with a stirring speed of 800 r / min to 1000 r / min to obtain the second mixed system.

[0010] Precise control of the formation conditions of the mixed system can ensure the stability and consistency of the hydrogen bond network construction, thereby steadily improving the staining rate and staining effect of curcumin.

[0011] Furthermore, in the step of adding the first mixed system, the second mixed system, and curcumin to water to prepare the dye solution, 800g~900g of the first mixed system is added per liter of water, and 900g~1000g of the second mixed system is added per liter of water.

[0012] The dye bath environment constructed in this way is conducive to improving the solubility of curcumin, reducing the spontaneous aggregation of curcumin, making it more suitable for the combination of curcumin and cotton fibers, improving dyeing uniformity and stability, and helping to reduce color difference.

[0013] Furthermore, the concentration of curcumin in the dye solution is 0.2 g / L to 0.4 g / L; In the step of dyeing cotton yarn with the dye solution, the temperature is 45℃~55℃, the time is 15min~20min, and the liquor ratio is 25~28:1.

[0014] Using this dye concentration facilitates the full dispersion of curcumin in the solution, enabling it to bind well with cotton fibers and preventing excessive curcumin concentration from accumulating in the dye bath. Furthermore, by combining this with specific dyeing process parameters, dyeing is carried out under suitable conditions, improving dyeing efficiency and ensuring dyeing effect and color fastness.

[0015] Furthermore, the preparation steps of the nanocellulose solution include: Acetic acid was added to the nanocellulose under stirring until the nanocellulose was completely dissolved. Water was then added to dilute the nanocellulose to a mass concentration of 2% to 4% to obtain the nanocellulose solution.

[0016] This preparation step yields a stable nanocellulose solution, which can better coat and protect the yarn and the dye on the yarn surface in subsequent steps. This concentration of nanocellulose solution helps to enhance the binding force between nanocellulose and yarn, while also helping to improve the strength and durability of the dyed yarn.

[0017] Furthermore, the cotton yarn undergoes a pre-washing treatment and a second drying treatment. The pre-washing treatment includes an enzyme washing treatment, and the treatment solution of the enzyme washing treatment contains 0.1g / L~0.5g / L of refining agent, 0.3g / L~1g / L of sodium carboxymethyl starch, and 0.6g / L~1.5g / L of cellulase.

[0018] Enzymatic washing, as a pretreatment, effectively removes oil and impurities from the surface of cotton fibers, reduces surface tension, and provides a better foundation for the dyeing process. Simultaneously, the synergistic effect of the refining agent, enzymes, and sodium carboxymethyl starch enhances the hygroscopic properties of the cotton fibers and the binding force of the dye, thereby improving the dyeing effect.

[0019] Furthermore, the enzyme washing treatment is performed at a temperature of 40℃~50℃ for 5min~10min, and at a pH of 5.0~6.5.

[0020] This treatment ensures the effective removal of oil and impurities from the fiber surface, while optimizing the surface properties of the cotton fibers. This provides a more uniform surface for subsequent dyeing, enhancing the uniformity and effectiveness of the dyeing process.

[0021] Furthermore, the pre-washing treatment also includes an ultrasonic water washing treatment, wherein the frequency of the ultrasonic water washing treatment is 30kHz~45kHz and the time is 6min~10min.

[0022] Ultrasonic washing effectively removes tiny impurities adhering to the surface of cotton fibers. The ultrasound enhances water permeability, making it easier to remove impurities, thus smoothing the dyeing process and improving the dyeing effect.

[0023] Furthermore, the temperature of the second drying process is 100℃~120℃, and the processing speed is 5 minutes.

[0024] This drying process allows pre-treated cotton yarn to be dried while ensuring that enzymes are inactivated at this temperature, preventing adverse effects on subsequent processing steps. This temperature setting guarantees drying efficiency and yarn integrity, while avoiding fiber damage caused by overheating.

[0025] Furthermore, before the step of impregnating the dyed cotton yarn with nanocellulose solution, it is also rinsed with clean water for 5 to 10 minutes at a temperature of 40°C to 45°C.

[0026] Washing with clean water before padding removes any residual dye and other impurities from the cotton yarn surface, providing a cleaner surface for subsequent color-fixing. This process improves dyeing uniformity and quality, and ensures the colorfastness of the final product.

[0027] The beneficial effects of this invention are as follows: The novel dyeing method of this invention uses choline chloride, glycerol, urea, and water to form a hydrogen bond network, which enhances the interaction between molecules. Through the hydrogen bond network, the binding rate of curcumin to cotton fibers is increased, thereby increasing the dyeing rate of curcumin on cotton fibers without the need for heavy metal inorganic salts and rare earth elements. Combined with subsequent padding and drying treatments, a film formed by nanocellulose is formed on the surface of the cotton yarn, which protects the yarn and the dye already bound to the cotton fibers, improves the abrasion resistance of the yarn, and reduces subsequent fading. Overall, the color fastness of the dyed yarn is improved.

[0028] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application can be realized and obtained from the written description. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the steps of a novel staining method provided in an embodiment of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this invention.

[0031] It should be understood that, without conflict, any and all embodiments of the present invention can be combined with technical features of any other embodiment or multiple other embodiments to obtain other embodiments. The present invention includes such combinations to obtain other embodiments.

[0032] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter pertains. Where multiple definitions exist for a term, the definition herein shall prevail.

[0033] In recent years, colored denim fabrics have become increasingly popular. Colored denim is generally dyed using plant-based dyes, with curcumin being one of the commonly used colored dyes. Like most plant dyes, curcumin is difficult to dissolve and tends to aggregate in water, usually requiring the addition of heavy metal inorganic salts, which can easily lead to heavy metal residues. Some methods use rare earth elements, which are very expensive. Moreover, the colorfastness of yarns dyed using current techniques is relatively low.

[0034] This application provides a novel staining method, including the following steps: S1: Mix choline chloride and the first part of glycerol to form a first mixture system, and mix urea and the second part of glycerol to form a second mixture system.

[0035] S2: Add the first mixing system, the second mixing system and curcumin to water to prepare the dye solution.

[0036] S3: Dyeing cotton yarn with dye solution.

[0037] S4: The dyed cotton yarn is impregnated with a nanocellulose solution and then dried to obtain the finished dyed yarn.

[0038] This application embodiment creates a solution environment by mixing choline chloride, glycerol, and urea to enhance intermolecular interactions through a hydrogen bonding network. This solution effectively increases the solubility of curcumin in water, allowing it to bind more easily to cotton fibers and thus improving its dyeing rate. The binding force between curcumin and cotton fibers is significantly enhanced through hydrogen bonding in this solution, avoiding the problem of insufficient dyeing due to low solubility of curcumin in traditional dyeing methods. Subsequently, the dyed cotton yarn is impregnated with a nanocellulose solution to form a thin film. This film not only protects the curcumin already bound to the fibers, preventing its loss, but also enhances the color fastness and durability of the yarn. Furthermore, the presence of the nanocellulose film improves the yarn strength, resulting in better stability and service life during subsequent processing.

[0039] The specific steps of step S1 include: Weigh out choline chloride and glycerol in a mass ratio of 1:1, and mix them at 75°C with a stirring speed of 800 r / min to 1000 r / min to obtain the first mixture system; weigh out urea and glycerol in a mass ratio of 1:1, and mix them at 75°C with a stirring speed of 800 r / min to 1000 r / min to obtain the second mixture system.

[0040] Choline chloride and glycerol, and urea and glycerol were mixed separately at specific temperatures and stirring speeds to ensure the homogeneity and stability of the mixtures, thus providing a stable solution environment for subsequent dyeing. This environment not only improves the solubility of curcumin but also reduces its spontaneous aggregation, allowing the dye to be evenly dispersed in the solution and thus better penetrate the fiber, improving the dyeing effect.

[0041] Step S2 can be prepared in the dye bath, adding 800g~900g of the first mixing system per liter of water and 900g~1000g of the second mixing system per liter of water. This helps improve the solubility of curcumin and allows it to bind well with cotton fibers, ensuring uniformity of the dyeing effect. It avoids the situation in traditional dyeing where the dye cannot fully penetrate the fiber, thus improving the dyeing rate and ensuring uniform color of the final product.

[0042] The concentration of curcumin in the dye solution is 0.2 g / L to 0.4 g / L. An appropriate curcumin concentration can prevent dye waste while ensuring the dyeing effect. It should be noted that "L" in "g / L" refers to the total volume of the water, the first mixing system, and the second mixing system after mixing.

[0043] In step S3, the temperature is 45℃~55℃, the time is 15min~20min, and the liquor ratio is 25~28:1, depending on the dye concentration.

[0044] The relatively mild dyeing temperature promotes the binding of curcumin to cotton fibers while avoiding damage to the fibers and dyes from high temperatures. The liquor ratio during the dyeing process ensures that the dye fully contacts the fiber surface and penetrates evenly into the fiber interior, maximizing the amount of dye that can bind to the cotton yarn. This moderate temperature and time range ensures that curcumin forms a strong bond on the fiber surface, which is beneficial for improving the color fastness and dyeing quality of the finished dyed yarn.

[0045] Nanocellulose can form a film on the surface of yarn, protecting the dye and simultaneously enhancing the yarn strength to some extent. Specifically, the preparation steps for the nanocellulose solution include: Acetic acid was added to the nanocellulose under stirring until the nanocellulose was completely dissolved. Water was then added to dilute the nanocellulose to a mass concentration of 2% to 4% to obtain a nanocellulose solution.

[0046] This solution effectively interacts with the yarn surface, forming a uniform nanocellulose film on the dyed yarn surface. After impregnation, the nanocellulose adheres to the yarn, which is then dried at a temperature of 100℃~120℃. This film not only effectively protects the curcumin dye, preventing dye loss, but also enhances the yarn's durability and strength. The nanocellulose film also exhibits excellent adhesion and protective properties, delaying damage and fading of the yarn due to friction during use, thereby improving the colorfastness of the dyed product.

[0047] Preferably, between steps S3 and S4, a water rinse is performed for 5-10 minutes at a temperature of 40-45°C. This effectively removes loose dye, unfixed dye, and impurities from the yarn surface, ensuring a more uniform and clear color after dyeing and improving colorfastness. Water rinsing removes excess dye that may affect the quality of the finished product, guaranteeing that the dyed yarn meets high colorfastness standards.

[0048] The cotton yarn undergoes a pre-washing treatment S01 and a second drying treatment S02. The pre-washing treatment S01 includes an enzyme washing treatment S011. In step S011, the treatment solution contains 0.1 g / L to 0.5 g / L of refining agent, 0.3 g / L to 1 g / L of sodium carboxymethyl starch, and 0.6 g / L to 1.5 g / L of cellulase.

[0049] Cellulase acts on cotton fibers, disrupting their structure and increasing their moisture absorption. While cellulase breaks down molecular chains and reduces crystallinity, thus improving absorbency, it also lowers fiber strength, affecting subsequent processing. The enzyme washing formula mentioned above includes sodium carboxymethyl starch, which buffers the damage to the internal structure of the cotton yarn caused by cellulase, minimizing the strength loss and meeting the requirements of subsequent processing. The refining agent used is a common textile refining agent to remove oil and impurities from the yarn surface, reduce the surface tension of the cotton fibers, and promote the penetration of the enzyme washing agents into the micropores and cracks of the cotton fibers.

[0050] Accordingly, the temperature in step S011 is 40℃~50℃, the time is 5min~10min, and the pH is 5.0~6.5, which can effectively remove impurities and oil stains from the surface and interior of the cotton fibers, while improving the fiber's hygroscopicity and dye adsorption capacity. By precisely controlling these parameters, excessive damage to the cotton fiber structure can be avoided, preventing excessive decrease in fiber strength during subsequent dyeing and fiber processing, thus ensuring the dyeing effect and smooth progress of subsequent processing.

[0051] In a preferred embodiment, step S01 further includes an ultrasonic water washing treatment S012, in which the ultrasonic frequency is 30kHz~45kHz and the time is 6min~10min. Ultrasonic water washing, following enzyme washing, can effectively remove fine impurities adhering to the surface of cotton fibers, making the impurity removal more thorough.

[0052] In step S012, the temperature is 100℃~120℃, and the processing speed is 5 minutes. During drying, at this temperature, residual enzymes on the yarn are inactivated, preventing them from continuing to chemically react with the fibers in subsequent processing, thus protecting the fiber structure and strength. This temperature setting not only ensures drying efficiency but also allows for rapid removal of moisture from the yarn surface, avoiding fiber damage and strength reduction caused by overheating.

[0053] Example 1 according to Figure 1 Implement this application, Figure 1 In the diagram, ellipses represent materials, hollow arrows indicate material flow direction, squares represent steps to be performed, and solid arrows indicate the sequence of steps. The specific implementation process is as follows: Weigh out choline chloride and glycerol in a 1:1 mass ratio, and mix them at 75°C with a stirring speed of 1000 r / min to obtain the first mixture. Weigh out urea and glycerol in a 1:1 mass ratio, and mix them at 75°C with a stirring speed of 1000 r / min to obtain the second mixture.

[0054] Prepare the dye solution in the dye bath by adding 800g of the first mixing system and 1000g of the second mixing system per liter of water. The final concentration of curcumin is 0.3g / L. Maintain the temperature of the dye solution at 55℃.

[0055] The cotton yarn underwent pretreatment, specifically an enzymatic wash at 45℃ for 10 minutes. The treatment solution contained 0.4 g / L of refining agent (Foshan Chunfeng New Materials CF-4J), 0.5 g / L of sodium carboxymethyl starch (Anhui Weimao Biotechnology Co., Ltd.), and 1.2 g / L of cellulase (Anhui Weimao Biotechnology Co., Ltd.). The pH was maintained at 5.0–6.5 using an acetate-sodium acetate buffer system. Next, an ultrasonic wash was performed at 30 kHz for 6 minutes. Finally, a second drying process was conducted at 120℃ for 5 minutes.

[0056] The pretreated cotton yarn was dyed with the prepared dye solution for 20 minutes at a liquor ratio of 28:1.

[0057] The dyed cotton yarn was rinsed with clean water at a temperature of 40℃ for 5 minutes.

[0058] The cotton yarn, which had been rinsed with water, was impregnated with a nanocellulose solution. The nanocellulose solution (Shanghai Wanzhao Fine Chemical Co., Ltd.) had a mass concentration of 2%.

[0059] Finally, a first drying process is performed at a temperature of 100°C to obtain the finished dyed yarn of Example 1.

[0060] The yarn from Example 1 was used as the warp yarn and woven with the off-white 12S weft yarn to form the fabric of Weaving Example 1. The K / S value of the fabric of Weaving Example 1 was tested to be 14.6 and the wet rubbing color fastness was grade 3.

[0061] Comparative Example The yarn is dyed using traditional plant-based indigo dye: the yarn is first boiled at 90±5℃, then rinsed with clean water; then it undergoes pad dyeing, with the dye bath containing 10g / L curcumin, 12g / L reducing agent, 8g / L caustic soda, and 0.5g / L ferric sulfate mordant. The dyeing process involves padding four times. Finally, it is rinsed three times with clean water and dried to obtain the finished yarn in proportion.

[0062] The comparative yarn was used as the warp yarn and woven with off-white 12S weft yarn to form the fabric of Weaving Example 2. The fabric of Weaving Example 2 had the same density as the fabric of Weaving Example 1. The K / S value of the fabric of Weaving Example 2 was tested to be 7.9, and the wet rubbing color fastness was grade 1-2.

[0063] This invention can greatly improve the dyeing effect of curcumin, reduce the use of heavy metal inorganic salts in the dyeing process, change the traditional dyeing process that uses heavy metal salt chemicals as mordants, and provide a new environmentally friendly dyeing method with good dyeing effect and high color fastness.

[0064] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. "First" and "second" do not correspond to a specific order of execution; for example, "first drying treatment" may actually occur after "second drying treatment"; the order in which the "first mixing system" and "second mixing system" are prepared is not strictly limited.

[0065] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A novel staining method, characterized in that, Includes the following steps: Choline chloride and the first part of glycerol are mixed to form a first mixture system, and urea and the second part of glycerol are mixed to form a second mixture system; The first mixture, the second mixture, and curcumin were added to water to prepare a dye solution. The cotton yarn is dyed using the dye solution; The dyed cotton yarn is impregnated with a nanocellulose solution and then subjected to a first drying treatment to obtain the finished dyed yarn.

2. The novel staining method according to claim 1, characterized in that, The step of mixing choline chloride and the first portion of glycerol to form a first mixture includes: Weigh out the choline chloride and the first part of glycerol in a mass ratio of 1:1, and mix them at 75°C with a stirring speed of 800 r / min to 1000 r / min to obtain the first mixed system. The step of mixing urea and the second part of glycerol to form a second mixture includes: Weigh out the urea and the second part of glycerol in a mass ratio of 1:1, and mix them at 75°C with a stirring speed of 800 r / min to 1000 r / min to obtain the second mixed system.

3. The novel staining method according to claim 2, characterized in that, In the step of adding the first mixed system, the second mixed system, and curcumin to water to prepare the dye solution, 800g~900g of the first mixed system is added per liter of water, and 900g~1000g of the second mixed system is added per liter of water.

4. The novel staining method according to claim 3, characterized in that, In the dye solution, the concentration of curcumin is 0.2 g / L to 0.4 g / L; In the step of dyeing cotton yarn with the dye solution, the temperature is 45℃~55℃, the time is 15min~20min, and the liquor ratio is 25~28:

1.

5. The novel staining method according to claim 1, characterized in that, The preparation steps for the nanocellulose solution include: Acetic acid was added to the nanocellulose under stirring until the nanocellulose was completely dissolved. Water was then added to dilute the nanocellulose to a mass concentration of 2% to 4% to obtain the nanocellulose solution.

6. The novel staining method according to claim 1, characterized in that, The cotton yarn undergoes a pre-washing treatment and a second drying treatment. The pre-washing treatment includes an enzyme washing treatment, and the treatment solution of the enzyme washing treatment contains 0.1g / L~0.5g / L of refining agent, 0.3g / L~1g / L of sodium carboxymethyl starch, and 0.6g / L~1.5g / L of cellulase.

7. A novel staining method according to claim 6, characterized in that, The enzyme washing treatment is performed at a temperature of 40℃~50℃ for 5min~10min, and at a pH of 5.0~6.

5.

8. A novel staining method according to claim 6, characterized in that, The pre-washing process also includes an ultrasonic water washing process, wherein the frequency of the ultrasonic water washing process is 30kHz~45kHz and the time is 6min~10min.

9. A novel staining method according to claim 6, characterized in that, The temperature of the second drying process is 100℃~120℃, and the processing speed is 5 minutes.

10. A novel staining method according to claim 1, characterized in that, Before the step of impregnating the dyed cotton yarn with nanocellulose solution, it is also rinsed with clean water for 5 to 10 minutes at a temperature of 40°C to 45°C.

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