Preparation method of bio-based fiber with high color saturation and dyeing stability

Abstract

The invention discloses a preparation method of bio-based fibers with high color saturation and dyeing stability, and aims to improve the dyeing performance of PA11 fibers, optimize the dyeing process and reduce environmental pollution. The method comprises the following steps: firstly, preparing an acid dye solution, and dissolving an acid dye in water; then, the PA11 fibers are put into the dyeing liquid, the temperature of the dyeing liquid is set to be 70-80 DEG C, and the dyeing time is 10-20 minutes; and finally, cooling, cleaning and drying to obtain the dyed PA11 fiber. The PA11 fiber treated by the method is high in color saturation, good in stability and good in elongation. The dyeing method is easy and convenient to operate and short in dyeing time, has high dyeing efficiency and environmental protection characteristics, does not generate waste water and waste gas, and meets the requirement for environmental protection. Therefore, the dyeing method provided by the invention provides an effective and environment-friendly solution for dyeing the PA11 fiber, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to a method for preparing bio-based fibers with high color saturation and dyeing stability, and in particular to a technology for dyeing bio-based polymer fibers. Background Art

[0002] Polyamide 11 (PA11), a bio-based polymer made from castor oil, boasts excellent mechanical properties, chemical resistance, and weather resistance, making it widely used in the textile, automotive, and aviation industries. As a biodegradable and environmentally friendly material, PA11 has garnered widespread attention in the industry. However, the dyeing process for PA11 fibers presents a number of technical challenges, including difficulty in dyeing, uneven dyeing, and poor color fastness.

[0003] Compared to traditional synthetic fibers such as polyester and polyamide 6, PA11 fibers exhibit lower hydrophilicity during dyeing, making them difficult to combine with conventional dyes. This characteristic complicates the dyeing process for PA11 fibers, requiring specific dyeing conditions and dyes. Furthermore, PA11 fibers have a high melting point and a dense fiber structure, further increasing the difficulty of dyeing. To overcome these issues, traditional dyeing methods typically employ high-temperature, long-term processes, which not only consume significant energy but also cause significant environmental pollution, particularly through the generation of wastewater and exhaust gases during the dyeing process.

[0004] Currently, common PA11 dyeing methods include conventional dyeing and solution dyeing. Conventional dyeing typically uses acid dyes, disperse dyes, and other dyeing methods, requiring higher temperatures and longer dyeing times. Post-processing to remove excess dye is often necessary, resulting in a complex dyeing process and a heavy environmental burden. Furthermore, traditional PA11 dyeing processes often rely on chemical additives to solvents or dyes, which can pollute the environment.

[0005] The solution dyeing method is a relatively new dyeing technology. It involves adding the dye directly to the polymer melt before spinning, allowing the dye to bind to the fibers as they form, resulting in a uniform dyeing effect. This method has the advantage of reducing energy consumption and environmental pollution during the dyeing process while improving color fastness. However, the solution dyeing method also has some challenges, particularly regarding dye selection and dispersibility. Factors such as the dye's particle size, hydrophilicity, and compatibility with the polymer all affect the final dyeing effect.

[0006] Despite numerous attempts to dye PA11 using various dyes, including acid and reactive dyes, current research still presents challenges such as low dyeing efficiency, poor color fastness, and uneven dyeing. Acid dyes, in particular, present significant challenges in dyeing, including solubility, diffusivity, and adsorption, due to their molecular structure and weak affinity for PA11 fibers. Therefore, selecting appropriate acid dyes and optimizing dyeing processes to improve the dyeing performance of PA11 fibers remains a key issue in current dyeing technology research.

[0007] This invention addresses the existing issues of low dyeing efficiency and poor dyeing uniformity for PA11 fibers. By using acid red dye to dye PA11 and optimizing the dyeing process, the goal is to improve dyeing results and reduce environmental pollution. By studying the dyeing properties of acid red dye and PA11 fibers, a new solution is provided that not only improves dyeing efficiency but also achieves environmental friendliness during the dyeing process, promising promising market applications. Summary of the Invention

[0008] The present invention aims to provide a method for producing bio-based fibers with high color saturation and dyeing stability, aiming to overcome the problems of low dyeing efficiency, uneven dyeing, poor color fastness, and environmental pollution associated with existing dyeing processes. By optimizing dyeing conditions and dye selection, the present invention achieves efficient, environmentally friendly, and excellent dyeing results. The resulting fibers also exhibit high breaking strength and excellent mechanical properties.

[0009] To achieve the above objectives, the present invention provides the following technical solutions:

[0010] 1. Staining Method

[0011] A method for preparing bio-based fibers with high color saturation and dyeing stability, comprising the following steps:

[0012] Prepare acid red dye solution: dissolve acid red dye in water according to a predetermined ratio to prepare a dyeing solution, ensuring that the dye is fully dissolved in water to ensure uniformity of the dyeing effect.

[0013] Dyeing process: Place PA11 fiber in the dyeing solution, control the dyeing temperature at 70℃-80℃, and control the dyeing time at 10-20 minutes.

[0014] During the dyeing process, the acid red dye adheres evenly to the fiber surface through its affinity with the PA11 fiber, achieving an ideal dyeing effect.

[0015] Post-treatment: After dyeing, the fiber is cooled and washed to remove excess dye residue, ensuring a uniform color and no attached dye. It is then dried at a temperature not exceeding 80°C to obtain the final dyed PA11 fiber.

[0016] 2. Dye selection

[0017] The present invention uses acid red dye, a water-soluble dye with good dyeing properties and compatibility with PA11 fibers. Acid red dye molecules can form hydrogen bonds or ionic bonds with amino groups in PA11 fibers, ensuring a strong bond between the dye and the fiber, resulting in a more uniform and durable dyeing effect. In the present invention, the acid dye comprises the following components a) and b) mixed in a mass ratio of 80:20 to 95:5:

[0018] a) Benzothiazole dyes or their derivatives, used to form a strong bond with the amino groups in PA11 fibers;

[0019] b) Dye auxiliary agents, including one or more of the following auxiliary agents: dispersants (such as polyvinyl pyrrolidone PVP), solubilizers (such as sulfosuccinates), wetting agents or retarding agents, which are used to improve the solubility of dyes in water and the uniformity of the dyeing process.

[0020] The weight percentage of the acid dye in the dyeing solution is 5% to 10%.

[0021] 3. pH control of staining solution

[0022] The pH value of the dyeing solution in the present invention is controlled between 4.5 and 5.5. This pH range facilitates optimal bonding between the dye and the PA11 fiber, thereby avoiding excessive precipitation of the dye or uneven dyeing during the dyeing process.

[0023] 4. Optimization of dyeing effect

[0024] Under this dyeing method, after controlling the appropriate dyeing temperature (70-80°C) and dyeing time (10-20 minutes), the dyed PA11 fiber can achieve a high color depth and color fastness. Experiments show that the dyed PA11 fiber has a K / S value of 21.223, an L value of 18.79, an a value of 18.76, and a b value of 6.55 at a wavelength of 400 nm, showing good color saturation and brightness.

[0025] 5. Environmental protection and efficiency

[0026] The dyeing method of the present invention is environmentally friendly. During the dyeing process, the dye completely dissolves and evenly adheres, avoiding the wastewater, exhaust gas, and solid waste generated in traditional dyeing processes, thereby reducing environmental pollution. Furthermore, the present invention utilizes a low-temperature dyeing process, significantly reducing energy consumption and improving production efficiency compared to traditional high-temperature dyeing methods.

[0027] 6. Fiber properties after dyeing

[0028] The PA11 fibers obtained using this dyeing method exhibit excellent dyeing results and mechanical properties. The dyed PA11 fibers not only have a uniform color but also maintain their original high ductility and other properties. Experiments have shown that the elongation at break of the dyed PA11 fibers is 314.51%. This dyeing method is suitable for large-scale industrial production and has broad application prospects.

[0029] The technical solution of the present invention can achieve the following advantages:

[0030] 1. Excellent dyeing effect: The present invention optimizes the dyeing conditions to improve the dyeing effect by the following methods:

[0031] ①Select benzothiazole acid red dyes containing sulfonic acid groups to improve the affinity of the dyes with the amino groups of PA11 fibers;

[0032] ②Controlling the pH value of the dyeing solution in the range of 4.5-5.5 is conducive to the charge adsorption balance of the dye on the surface of PA11 fiber;

[0033] ③Control the dyeing temperature at 70℃-80℃ and the dyeing time at 10-20 minutes to achieve effective diffusion and fixation of the dye under medium and low temperature conditions;

[0034] ④ Add appropriate amount of auxiliaries (such as dispersants and retarder) to improve the stability and permeability of the dye in the dye bath.

[0035] 2. Excellent mechanical properties: The PA11 fiber obtained after dyeing has a high elongation at break.

[0036] 3. Environmental protection and energy saving: The low-temperature dyeing process is used to significantly reduce energy consumption, while reducing the discharge of wastewater and exhaust gas, meeting green environmental protection requirements.

[0037] 4. Simplified process: This dyeing method is easy to operate, has a short dyeing time, and is suitable for large-scale production applications.

[0038] 5. Improve dyeing efficiency: By optimizing the ratio of dyeing liquid, temperature and dyeing time, the dyeing efficiency is improved to ensure the color uniformity and dyeing depth of PA11 fiber.

[0039] In summary, the present invention provides a PA11 fiber acid red dyeing method that is efficient, environmentally friendly, has excellent dyeing effect and excellent machine performance, which can meet the modern textile industry's demand for environmentally friendly and efficient dyeing technology and provide a new solution for the widespread application of PA11 fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is an optical photograph of PA11 fiber produced by melt spinning in the examples;

[0041] Figure 2 This is a physical picture of the selected acid red dye (benzothiazole type);

[0042] Figure 3 The PA11 fiber obtained after dyeing in Example 1;

[0043] Figure 4 It is a spectrophotometer used to measure the K / S value after dyeing;

[0044] Figure 5 is the K / S value measured at a wavelength of 400 nm in Example 1, reflecting the depth of dyeing;

[0045] Figure 6 Diagram of the electronic strength tester used to determine the elongation at break;

[0046] Figure 7 This is a graph of the elongation at break of the PA11 fiber of Example 1, wherein the multiple curves correspond to experimental data from different batches. DETAILED DESCRIPTION

[0047] In order to better understand the technical solution of the present invention, the dyeing method of the present invention is described in detail below in conjunction with specific examples. The dyeing process and operating steps involved in the examples are only used to illustrate the application of the present invention and should not be regarded as limiting the present invention.

[0048] Experimental Materials:

[0049] 1. PA11 fiber: PA11 polymer synthesized from castor oil is used to prepare fibers using a melt spinning method with a fiber diameter of 30 μm.

[0050] 2. Acid red dye: Use acid red dye, water-soluble dye with a molecular weight of 500-600, and choose acid dye suitable for combining with PA11 fiber.

[0051] 3. Dyeing solution: Dissolve the acid red dye in deionized water at a ratio of 10% of the dyeing solution mass, ensuring that the dye is completely dissolved and forms a uniform solution.

[0052] 4. Auxiliary reagents: Select and use appropriate amounts of pH regulators and auxiliary agents to optimize the dyeing process and improve the uniformity of the dyeing solution and the dispersibility of the dye.

[0053] Implementation steps:

[0054] 1. PA11 fiber preparation:

[0055] The desired PA11 fibers are cut into segments and pre-treated. The pre-treatment step involves washing the PA11 fibers in warm water to remove surface impurities and dust.

[0056] Subsequently, the PA11 fiber was placed in a vacuum drying oven and dried at 80°C for 24 hours to remove moisture from the fiber to prevent moisture from affecting the dyeing effect.

[0057] 2. Dissolution of acid red dye and preparation of staining solution:

[0058] Take an appropriate amount of acid red dye and auxiliary agent, add them to deionized water, dissolve them at a ratio of 10% (calculated based on the mass of acid red dye and dyeing solution), stir evenly to ensure that the dye is fully dissolved and dispersed in the water to form a dyeing solution.

[0059] Use pH test paper or a pH meter to check the pH value of the dye solution, and adjust the pH value to between 4.5 and 5.5 with acetic acid or sodium hydroxide as needed to ensure that the dye has the best adsorption effect within this pH range.

[0060] 3. Dyeing process:

[0061] Add PA11 fiber to the dyeing solution, making sure the dyeing solution completely covers the fiber. Set the dyeing solution temperature to 70℃-80℃.

[0062] Using the constant temperature dyeing method, soak the PA11 fiber in the dye solution for 10-20 minutes. During the dyeing process, the dye solution should be stirred regularly to ensure that the dye evenly penetrates every part of the fiber to avoid uneven dyeing.

[0063] 4. Post-processing:

[0064] After dyeing is completed, the dyed PA11 fiber is immediately taken out and placed in cold water to cool to room temperature to reduce the temperature and prevent excessive adsorption of the dye.

[0065] The fibers are then rinsed thoroughly in deionized water to remove any excess dye adhering to the surface. During the rinse process, ensure that the water is clear and no dye has escaped.

[0066] To further ensure uniformity of dyeing, rinse with clean water until the water is clear.

[0067] The cleaned fibers should be placed in a cool place to dry and dry to ensure that the fibers are not damaged and the color fastness is guaranteed.

[0068] 5. Dyeing effect evaluation:

[0069] Use a spectrophotometer to measure the K / S value, L value, a value, and b value of the dyed PA11 fiber to evaluate the dyeing effect. Use a fiber strength and elongation meter to test the elongation at break and other values ​​of the dyed PA11 fiber. By measuring these color parameters, we can determine the uniformity, saturation, and color stability of the dyeing.

[0070] Example 1: PA11 fiber dyeing experiment under optimized conditions

[0071] Materials: PA11 granules (Arkema Rilsan AMNO TLD model), drying temperature 80°C, drying time 24h;

[0072] Acid red dye (benzothiazole, molecular weight 550);

[0073] Dispersant: PVP (polyvinyl pyrrolidone);

[0074] pH adjuster: acetic acid / sodium hydroxide;

[0075] Deionized water.

[0076] step:

[0077] 1. Dissolve the dye in deionized water at 10% of the dye liquor mass, add 1% dispersant, and stir evenly;

[0078] 2. Adjust the pH to 4.5-5.0 and prepare the staining solution;

[0079] 3. Place PA11 fiber (melting temperature 250°C, extrusion rate 500 mm / min) produced by melt spinning into the dyeing solution;

[0080] 4. Set the dyeing temperature to 75°C and dye for 15 minutes, stirring to ensure uniformity;

[0081] 5. Cool, wash to remove loose color, and then dry at low temperature.

[0082] 6. Performance results:

[0083] Figure 5 As shown, the K / S value is 21.223, indicating a high depth of staining;

[0084] Figure 7The corresponding sample exhibited an elongation at break of 314.51%, demonstrating excellent mechanical properties after dyeing. Compared to conventional acid dyeing methods, the PA11 fiber produced in this example exhibited a K / S ratio increase of over 20% and an elongation at break of over 15%, demonstrating enhanced color saturation and mechanical properties.

[0085] The embodiments described above are merely some preferred embodiments of the present invention and are not intended to limit the present invention. Persons skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent substitution or equivalent transformation falls within the scope of protection of the present invention.

Claims

1. A method for preparing bio-based fibers with high color saturation and dyeing stability, characterized in that: include: a) preparing a dyeing solution: dissolving an acidic red dye having an affinity structural group in water in a proportion to form a dyeing solution, wherein the dye molecular structure can form a stable bond with the amino group in the PA11 fiber; b) Low-temperature rapid dyeing: Place the PA11 fiber in the dyeing solution and dye it at a temperature range of 70℃-80℃ for 10-20 minutes to allow the dye to fully penetrate and bind to the fiber; c) cooling and washing the PA11 fiber treated in step b) to remove excess dye from the surface; d) Drying treatment: The washed fibers are dried at a low temperature not exceeding 80° C. to obtain PA11 fibers with uniform dyeing and high breaking strength.

2. The method for preparing bio-based fibers with high color saturation and dyeing stability according to claim 1, characterized in that: The acid dye comprises the following components a) and b) mixed in a mass ratio of 80:20 to 95:5: a) Benzothiazole dyes or their derivatives, used to form a strong bond with the amino groups in PA11 fibers; b) Dye auxiliary agents, including one or more of the following auxiliary agents: dispersants, solubilizers, wetting agents, and retarding agents.

3. The method for preparing bio-based fibers with high color saturation and dyeing stability according to claim 1, characterized in that: The dissolution concentration of the acid dye is 5% to 10% of the weight of the dyeing solution.

4. The method for preparing bio-based fibers with high color saturation and dyeing stability according to claim 1, characterized in that: The pH of the dyeing solution is controlled at 4.5-5.

5.

5. The method for preparing bio-based fibers with high color saturation and dyeing stability according to claim 1, characterized in that: The PA11 fiber is prepared by melt spinning of PA11 particles that have been dried.

6. The method for preparing bio-based fibers with high color saturation and dyeing stability according to claim 5, characterized in that: The melt spinning parameters of the material are: melting temperature of 240° C. to 260° C., and melt extrusion speed of 450 mm / min to 550 mm / min.

7. A bio-based fiber with high color saturation and dyeing stability, characterized in that: The method is prepared by the method according to any one of claims 1 to 6.

8. The bio-based fiber with high color saturation and dyeing stability according to claim 7, characterized in that: The red PA11 fiber has the following dyeing properties: K / S value at a wavelength of 400nm is 21.223, L value is 18.79, a value is 18.76, b value is 6.55, and elongation at break is 314.51%; Compared with the existing conventional acid dyeing method, the K / S value is increased by more than 20%, and the elongation at break is increased by more than 15%, showing higher color saturation and mechanical properties.

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