A method of dyeing nylon

Abstract

The present application relates to the technical field of textiles, and particularly provides a nylon dyeing method.In the dyeing method, a dyeing solution solvent is composed of ethanol and water, and the volume percentage of the ethanol is not less than 60%; the nylon material to be dyed is added into the dyeing solution for dyeing, and the dyed nylon is obtained after soaping.The present application does not need to use acid, alkali and salt additives, simplifies the dyeing process, realizes efficient dyeing of the nylon material, significantly improves the dyeing rate of the dye, effectively reduces the water consumption for dyeing, and greatly reduces the treatment difficulty of the dyeing wastewater.

Description

Technical Field

[0001] This invention relates to the field of dyeing technology, and more specifically to a method for dyeing nylon. Background Technology

[0002] Dyeing nylon fiber materials usually requires an acidic or alkaline environment and involves multiple steps and processes. The main dyeing step typically requires the addition of salt auxiliaries, resulting in complex wastewater composition and significant treatment challenges. Summary of the Invention

[0003] Therefore, it is necessary to provide a nylon dyeing method that is more environmentally friendly and can reduce the difficulty of treating dyeing wastewater.

[0004] The present invention adopts the following technical solution: This invention provides a method for dyeing nylon, comprising the following steps: A dyeing solution is prepared using reactive dyes and a solvent, wherein the solvent consists of ethanol and water, and the volume percentage of ethanol is not less than 60%. The nylon material to be dyed is added to the dyeing solution for dyeing, forming bath-dyed nylon material; The bath-dyed nylon material is soap-washed to obtain dyed nylon.

[0005] In some embodiments, the ethanol volume percentage in the dye solution is not less than 60%, the dye concentration is 0.2~4% (owf), the dyeing temperature is 60~110℃, and the dyeing time is 5~50 min, which can achieve effective dyeing of nylon.

[0006] In some embodiments, the ethanol volume percentage in the dyeing solution is not less than 80%, the dye concentration is 1-4% (owf), the dyeing temperature is 80-110℃, and the dyeing time is 5-20 min. After soaping, the K / S value of the dyed nylon is generally greater than 8, the dyeing rate is greater than 50%, and the overall dyeing effect is good.

[0007] In some embodiments, the volume percentage of ethanol in the dyeing solution is not less than 90%, the concentration of the dye is 1-4% (owf), the dyeing temperature is 80-110℃, and the dyeing time is 5-20 min. After soaping, the K / S value of the dyed nylon is generally greater than 10, the dyeing rate is greater than 90%, and the overall dyeing effect is good.

[0008] In some embodiments, the volume percentage of ethanol in the dye solution is not less than 95%, the concentration of the dye is 1-2% (owf), the dyeing temperature is 90-100℃, and the dyeing time is 5-20 min. After soaping, the K / S value of the dyed nylon is generally greater than 20, the dyeing rate is greater than 95%, and the overall dyeing effect is excellent.

[0009] In some embodiments, the dye solution contains 99% ethanol by volume, the dye concentration is 1-2% (owf), the dyeing temperature is 100°C, and the dyeing time is 5-20 min. This results in optimal dyeing effect.

[0010] In some embodiments, the dye solution contains 60-75% ethanol by volume, the dye concentration is 20 g / L, and dyeing is performed at 30°C for 24 h. After soaping, the K / S value of the dyed nylon is generally greater than 10. This method uses cold-pile dyeing and low-temperature soaping, which can significantly save energy costs.

[0011] In some embodiments, the nylon material is at least one selected from PA6, PA6 blends, PA56, PA56 blends, PA66, and PA66 blends. The reactive dye is selected from at least one selected from Reactive Blue 20, Reactive Red 195, and Reactive Yellow 145.

[0012] In some embodiments, the ethanol in the dye solution can be recovered and reused.

[0013] In some embodiments, the soaping step uses a soaping solution containing soap powder and sodium carbonate, with a bath ratio of 1:50, a temperature of 100°C, and a duration of 20 minutes.

[0014] Compared with the prior art, the core technical advantages and beneficial effects of this invention are as follows: The dyeing method of this invention uses a dye bath solvent composed of ethanol and water, with the ethanol volume percentage not less than 60%. The nylon material to be dyed is added to the dye bath for dyeing, and after soaping, dyed nylon is obtained. This method eliminates the need for acid, alkali, and salt auxiliaries, simplifying the dyeing process while achieving efficient dyeing of nylon materials. It significantly improves the dye uptake rate, effectively reduces dyeing water consumption, and greatly alleviates the difficulty of dyeing wastewater treatment. Furthermore, the solution of this application is applicable to various forms of products, such as fibers, yarns, and fabrics.

[0015] Using a high proportion of ethanol as the main solvent has two advantages. First, it reduces the polarity and free water content of the system, weakens the hydration layer around the reactive dye, and reduces competitive hydrolysis between reactive groups and water, allowing more dye to retain its effective activity. Second, ethanol can enter the amorphous region of nylon and form dynamic hydrogen bonds with the amide groups in the polyamide segments, moderately weakening the original hydrogen bond network between nylon molecular chains, increasing the mobility and free volume of the amorphous region segments, thereby forming mass transfer channels conducive to dye diffusion. The small amount of water is not simply used as a diluent, but rather to maintain the necessary environment for the dissolution, dissociation, and activation of the reactive dye, enabling the dye molecules to maintain their migration ability and reactivity in the ethanol system. Therefore, in a mixed solvent system with ethanol as the main component and a small amount of water, reactive dyes no longer rely primarily on salt-induced dyeing or acid-base regulation, but achieve rapid dyeing of nylon materials through a synergistic environment of low hydration, high diffusion, and low hydrolysis. Attached Figure Description

[0016] Figure 1 The image shows the DSC curves before and after nylon PA6 staining in Example 1.

[0017] Figure 2 This is a TG curve before and after nylon PA6 staining in Example 1.

[0018] Figure 3 This is a comparison of the K / S values ​​curves after staining nylon PA6 in different experimental cases.

[0019] Figure 4 This is a picture of the nylon dyed material prepared by cold pile dyeing experiment using ethanol and water in a volume ratio of 75:25 in Example 7.

[0020] Figure 5 This is a photograph of the nylon PA6 dyed with Reactive Blue 20 in Example 8.

[0021] Figure 6 This is a photograph of the dyeing of nylon PA56 with RY145 in Example 9. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention. The following embodiments are only used to illustrate the present invention, and are not intended to limit the scope of the present invention. Based on the specific embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention. In the embodiments of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; in the embodiments of the present invention, unless specifically specified, the technical means used are conventional means well known to those skilled in the art.

[0023] Terminology Explanation: The K / S value is an important indicator of the dyeing depth of a fabric, based on the Kubelka-Munk theory. K is the absorption coefficient, and S is the scattering coefficient. A larger K / S value indicates a darker fabric color, and vice versa. The spectral reflectance of the dyed fabric is measured using a colorimeter (spectral colorimeter), and then converted into a K / S value by a computer program.

[0024] The calculation formula is: Where R represents the observed reflectance value of the dyed fiber at the maximum absorption wavelength.

[0025] Dye uptake rate refers to the percentage of dye adsorbed onto the fiber during the dyeing process relative to the total amount of dye input. The residual liquor method is used, and the absorbance of the dye liquor before and after dyeing is measured using a UV-Vis spectrophotometer. The dye uptake rate (E, %) is calculated based on the change in absorbance.

[0026] The calculation formula is: Among them, A dye-before With A dye-after These represent the absorbance values ​​of the dye solution at the initial staining stage and the residual solution after staining, respectively; while n dye-before With n dye-after This corresponds to the dilution factor for each of the two types of solutions.

[0027] Total fixation refers to the percentage of dye that remains fixed on the fiber after soaping, relative to the initial amount of dye. It reflects the strength of the bond between the dye and the fiber and is an important indicator for evaluating the dyeing effect.

[0028] The calculation formula is: The subscripts soap-before and soap-after represent the K / S values ​​of the dyed textile fiber samples before and after soaping, respectively.

[0029] Key experimental materials: Reactive dyes, available commercially: Reactive Blue 20, Reactive Red 195, Reactive Yellow 145.

[0030] Nylon material to be dyed: Nylon 6 (PA6): Wuxi Ruiqi New Material Technology Co., Ltd., 135 g / m², model RQ-1 knitted fabric.

[0031] Nylon 66 (PA66): Luthai Textile Co., Ltd., 40D yarn.

[0032] Nylon 56 (PA56): Institute of Systems Engineering, Academy of Military Sciences, 194 g / m².

[0033] The following example illustrates this.

[0034] Example 1 This embodiment provides a nylon dyeing method, including the following steps: S1, Prepare the dye solution.

[0035] The reactive dye (Reactive Blue 20, C) 20 H 17 N4Na3O 15 S4) is added to a mixed solvent containing water and ethanol to prepare a dye solution, wherein the amount of dye is 1.00% (owf) and the volume ratio of ethanol to water is 99:1.

[0036] S2, high-temperature staining.

[0037] The nylon to be dyed (PA6, H[-NH-(CH2)5-CO-]) n Add the OH material to the above dyeing solution at a liquor ratio of 1:50, dye at 100℃ for 20 min, remove the fabric, and obtain bath-dyed nylon material.

[0038] S3, soap wash.

[0039] The nylon material was soaped using a soaping solution containing 2 g / L soap powder and 2 g / L sodium carbonate at a liquor ratio of 1:50, a soaping temperature of 100℃, and a time of 20 min to obtain dyed nylon.

[0040] The K / S values ​​of the nylon PA6 material before dyeing and after soaping in this embodiment were tested. The absorbance of the dyeing solution and soaping solution before and after application was measured, and the dyeing rate and total fixation rate were calculated and statistically analyzed.

[0041] The results show: This embodiment focuses on the dyeing treatment of nylon (PA6) material. The K / S value before soaping is 21.08, and the K / S value after soaping is 20.14. The dyeing rate is 99.22%, and the total fixation rate is 94.80%.

[0042] Example 2 Referring to the nylon dyeing method and parameters in Example 1: the amount of Reactive Blue 20 dye is 1.00% (owf), the volume ratio of ethanol to water is 99:1, etc. This example only explores the effect of different solvent ratios on the dyeing treatment of nylon (PA6) materials.

[0043] The test statistics are shown in the table below: Table 1. Statistical table of the influence of different solvent ratios on the dyeing effect of PA6 material. The results in the table above show that using a high proportion of ethanol with 1.00% Reactive Blue 20 dye results in better dyeing of nylon (PA6) materials.

[0044] Example 3 Referring to the nylon dyeing method and parameters in Example 1: the amount of Reactive Blue 20 dye was 1.00% (owf), and the volume ratio of ethanol to water was 99:1, etc. This example only investigates the effect of different dyeing temperatures on the dyeing treatment of nylon (PA6) materials. The test statistical results are shown in the table below: Table 2. Statistical table of the influence of different dyeing temperatures on the dyeing effect of PA6 material. The results in the table above show that using 1.00% Reactive Blue 20 dye with a high proportion of ethanol and high temperature conditions results in better dyeing of nylon (PA6) materials.

[0045] Example 4 Referring to the nylon dyeing method and parameters in Example 1: the volume ratio of ethanol to water is 99:1, and Reactive Blue 20 is dyed at 100℃ for 20 min, etc. This example only explores the effect of different dye concentrations on the dyeing treatment of nylon (PA6) materials.

[0046] The test statistics are shown in the table below: Table 3. Statistical table of the influence of different dye concentrations on the dyeing effect of PA6 material. Example 5 Referring to the nylon dyeing method and parameters in Example 1: the ethanol to water volume ratio was 99:1, and Reactive Blue 20 was used for dyeing at 100℃, this example only investigates the effect of different dyeing times (2.00% owf) on the dyeing treatment of nylon fiber (PA6) material. The test results are shown in the table below: Table 4. Statistical table of the effect of dye concentration of 2.00% and different dyeing time on the dyeing effect of PA6 material. Example 6 This embodiment provides a nylon dyeing method, including the following steps: S1, Prepare the dye solution.

[0047] The reactive dye (Reactive Blue 20, C) 20 H 17 N4Na3O 15S4) Add the dye to a mixed solvent containing water and ethanol to prepare a dyeing solution, wherein the amount of dye is 2.00% (owf), and the volume ratio of ethanol to water is 99:1. The ethanol used in this embodiment is the ethanol recovered from the dyeing waste liquid (the test content is 99% of the content of anhydrous ethanol used).

[0048] S2, high-temperature staining.

[0049] Add the nylon (PA6) material to be dyed to the above dyeing solution and dye at 100℃ for 10 min to obtain bath-dyed nylon.

[0050] S3, soap wash.

[0051] The nylon was soaped using a soaping solution containing 2 g / L soap powder and 2 g / L sodium carbonate at a liquor ratio of 1:50, a soaping temperature of 100℃, and a time of 20 min to obtain dyed nylon.

[0052] The K / S values ​​of the nylon material before dyeing and after soaping in this embodiment were tested, and the absorbance of the dyeing solution and soaping solution was measured. The dyeing rate and total fixation rate were calculated and statistically analyzed.

[0053] The results showed that, in this embodiment, the dyeing treatment of nylon (PA6) material had a K / S value of 30.38 before soaping and a K / S value of 29.23 after soaping, with a dyeing rate of 99.59% and a total fixation rate of 95.83%.

[0054] Comparative Example 1 Referring to the nylon dyeing method, process steps, and parameter conditions in Example 1, this comparative example investigated Reactive Blue 20 dyeing using only pure water as the solvent, with a dye concentration of 2.00% owf, and dyeing at 100°C for 10 min in pure water.

[0055] The K / S values ​​of the comparative nylon (PA6) material before dyeing and after soaping were tested.

[0056] The results showed that the K / S value of Reactive Blue 20 combined with pure water environment dyeing nylon (PA6) material was 6.30 before soaping and 5.41 after soaping.

[0057] Comparative Example 2 Referring to the nylon dyeing method, process steps, and parameters in Example 1, this comparative study only used 10 g / L sodium sulfite aqueous solution as solvent, dye concentration of 2.00% owf, and dyeing at 60℃ for 40 min.

[0058] The K / S values ​​of the comparative nylon (PA6) material before dyeing and after soaping were tested.

[0059] The results showed that when Reactive Blue 20 was combined with sodium sulfite aqueous solution to dye nylon (PA6) material, the K / S value before soaping was 6.30 and the K / S value after soaping was 5.41.

[0060] Comparative Example 3 (Routine Staining): Nylon (PA6) material was dipped and rubbed twice in a 2.00% owf dye bath (Reactive Blue 20 as dye, water as solvent), followed by drying at 100°C for 40 seconds. The resulting nylon fiber fabric was then dipped and rubbed once in a 200 g / L sodium sulfate solution at pH 4.5, and steamed at 100°C for 3 minutes. Finally, it was dipped and rubbed once in a 40 g / L sodium carbonate and 200 g / L sodium sulfate solution, and steamed at 100°C for 3 minutes to obtain conventionally dyed nylon fabric.

[0061] Test results show that the K / S value of conventionally dyed nylon (PA6) with Reactive Blue 20 was 0.37 before soaping and 0.21 after soaping.

[0062] Further integration Figure 3 As can be seen from the comparison between Example 5 and Comparative Examples 1 to 3, the preferred high-temperature dyeing with high proportion of ethanol is a reactive dye concentration of 2.00%, and dyeing at 100°C for 10 minutes is sufficient.

[0063] Example 7 This embodiment investigates the effects of using different solvents in the staining solution for cold pile staining. Specific methods include: S1, Prepare the dye solution.

[0064] The reactive dye (Reactive Red 195, C) 31 H 19 ClN7Na5O 19 S6) is added to different solvents to prepare dyeing solutions with a dye concentration of 20 g / L.

[0065] S2, cold pile staining.

[0066] The nylon (PA6) material to be dyed was added to the above dyeing solution at a liquor ratio of 1:5, and dyed at 30°C for 24 h to obtain bath-dyed nylon material.

[0067] S3, soap wash.

[0068] The dyed nylon was obtained by soaping with a soaping solution containing 2 g / L soap powder at a bath ratio of 1:20, a soaping temperature of 40℃, and a time of 10 min.

[0069] The K / S values ​​of the comparative nylon (PA6) material before dyeing and after soaping were tested. The test results are shown in the table below: Table 4. Statistical table of the influence of cold reactor environment on the staining effect of PA6. The above experiments show that: (1) When a solvent system with a high proportion of ethanol and water is used, high-temperature and high-efficiency dyeing of nylon (PA6) material can be achieved without the need to add acid, alkali and salt auxiliaries.

[0070] (2) In particular, when the volume fraction of ethanol in the dyeing solution reaches 99%, the system exhibits excellent dyeing performance: under the conditions of dye concentration of 2.00% (owf) and dyeing at 100 ℃ for 10 min, the K / S value before soaping reaches 32.09, the K / S value after soaping is 30.48, the dyeing rate reaches 99.09%, and the total fixation rate reaches 94.11%, which is significantly better than the pure water system and the traditional multi-bath dyeing process.

[0071] (3) As the proportion of ethanol in the dye solution decreases, the K / S value, dyeing rate and total fixation rate all decrease significantly, indicating that a high proportion of ethanol solvent is the key factor to obtain excellent high-temperature dyeing effect. At the same time, increasing the dyeing temperature can promote dye diffusion and fixation, while shortening the dyeing time to 5~10 min can still maintain a high dyeing rate and fixation rate.

[0072] (4) The dyeing rate and total fixation rate of recycled ethanol are still above 99% and above 95%, which indicates that the dyeing technology route has good solvent recycling performance and can effectively reduce production costs and environmental impact.

[0073] Additionally, refer to the test Figure 1 and 2 Furthermore, the present invention also conducted thermal stability tests on the nylon (PA6) material before and after dyeing in Example 1, and the results showed that: The DSC test curves show that the melting endothermic peaks of both the original nylon (PA6) material and the dyed nylon (PA6) material are located around 220℃, and the peak positions are basically consistent. This indicates that the high proportion of ethanol-water dyeing system did not damage the nylon crystal structure, nor did it cause degradation of the polyamide main chain. The melting peak of the dyed nylon (PA6) material is still obvious, indicating that the main crystalline structure of the fiber remains stable.

[0074] The TG test curves show that the nylon (PA6) material before and after dyeing undergoes major thermal decomposition in the range of approximately 420–470 °C, and the thermal weight loss behavior is basically the same, indicating that the dyeing process does not reduce the thermal stability of nylon (PA6) fiber.

[0075] The above experimental examples also show that after high-temperature dyeing of nylon (PA6) material, the K / S value of the fabric decreased after soaping at 100℃ compared to before soaping. The reasons are presumably due to two main factors: (1) The soaping solution contains a certain concentration of sodium carbonate, which forms a weak alkaline environment at 100 ℃. Under the action of high temperature and weak alkali, the surface hydrogen bonding and some weak interactions of the amide bonds and terminal amino groups in PA6 material are weakened to a certain extent, making it easier for dyes that rely solely on physical adsorption or are not firmly bound to desorb from the fiber surface.

[0076] (2) During the soaping process, a large amount of hot water continuously acts on the fiber surface. Reactive dyes that have not formed a stable bond with PA6 material, as well as dyes that have undergone hydrolysis but remain on the fiber surface or in the amorphous region, are more easily redissolved and diffused into the soaping solution under high temperature conditions due to the good water solubility of reactive dyes, thus being completely removed. Therefore, it is normal for the K / S value to decrease to a certain extent after soaping. In essence, it removes the surface floating color and dyes that are not firmly fixed, while the dyes that have truly entered the interior of the material and formed a stable physical reaction and partial chemical bond with PA6 are still retained. Although the K / S value after soaping is lower than before soaping, the resulting color is more stable, and the total fixation rate and soaping fastness are further improved.

[0077] Example 8 Referring to the nylon dyeing method process steps in Example 1: the concentration of Reactive Blue 20 dye is 1.00% owf, the volume ratio of ethanol to water is 99:1, and dyeing is carried out at 100℃ for 10 min, etc. This example explores the dyeing effect on different nylon materials.

[0078] The test statistics are shown in the table below: Table 5. Statistical table of the influence of Reactive Blue 20 on the dyeing effect of different nylon materials. Example 9 Referring to the nylon dyeing method and parameters in Example 1: different active dye concentrations were 1.00% owf, the volume ratio of ethanol to water was 99:1, and the dyeing time was 10 min at 100℃, etc. This example explores the dyeing effect of different dyes on different nylon materials.

[0079] The test statistics are shown in the table below: Table 6. Statistical table of the influence of different reactive dyes on the dyeing effect of different nylons. Not limited to the above experimental examples, this invention has discovered through extensive research that: (1) The reactive dyeing process for nylon uses a high proportion of ethanol as the main solvent. On the one hand, this reduces the polarity and free water content of the system, weakens the hydration layer around the reactive dye, reduces the competitive hydrolysis between the reactive groups and water, and allows more dyes to maintain effective activity. On the other hand, ethanol can enter the amorphous region of nylon material and form dynamic hydrogen bonds with the amide groups in the polyamide segments, moderately weakening the original hydrogen bond network between the molecular chains of nylon material, improving the mobility and free volume of the amorphous region segments, thereby forming a mass transfer channel that is conducive to dye diffusion. The small amount of water is not simply used as a diluent, but is used to maintain the necessary dissolution, dissociation, and activation environment for the reactive dye, so that the dye molecules can maintain their migration ability and reactivity in the ethanol system. Therefore, in a mixed solvent system with ethanol as the main component and a small amount of water, the dye no longer mainly relies on salt-induced dyeing or acid-base regulation, but achieves rapid dyeing of nylon fibers through a synergistic environment of low hydration, high diffusion, and low hydrolysis.

[0080] (2) For reactive dyeing of nylon, a dyeing temperature of 100℃ is preferred. This temperature is much lower than the melting temperature and thermal decomposition temperature of nylon, and will not cause damage to the material structure. However, this temperature is sufficient to significantly enhance the movement of chain segments in the amorphous region of nylon, reduce the dye diffusion barrier, and enable reactive dyes to quickly enter the interior of the material. Compared with dyeing conditions of 60℃ and 80℃, the free volume of the amorphous region of the material increases more fully at 100℃, and the dye diffusion rate is significantly improved. Therefore, higher K / S values, dyeing rates, and total fixation rates can be obtained. After the reactive dye enters the interior of nylon, it can first form hydrogen bonds, dipole-dipole interactions, and van der Waals forces with the nylon material chain segments through aromatic conjugated structures, sulfonic acid groups, hydroxyl groups, amide groups, etc., to achieve stable initial adsorption. At the same time, the vinyl sulfone type reactive groups or their precursor structures in the reactive dye maintain a certain reactivity under conditions of small amounts of water and high temperature, and can further bind with nucleophilic sites such as the terminal amino groups of the nylon material, thereby improving the total fixation fastness. Because ethanol significantly reduces the free water content of the system, the hydrolysis reaction of reactive dyes is inhibited. Therefore, even without the addition of alkali, dye deactivation can be reduced. At the same time, because ethanol weakens the hydration layer and promotes the diffusion of dye into the fiber interior, the dye no longer needs to rely on a large amount of inorganic salts to reduce solubility or shield charges to achieve high dye uptake.

[0081] (3) A synergistic dyeing mechanism was formed, which consists of "ethanol reducing free water and hydration - a small amount of water maintaining dye activation - ethanol relaxing the hydrogen bond network in the amorphous region of nylon - 100℃ promoting chain segment movement and dye diffusion - physical adsorption and partial chemical bonding for joint fixation". This mechanism explains why the technical solution can still achieve a high dyeing rate and total fixation rate without the need for acid, alkali and salt auxiliaries. It also shows that this method has advantages over traditional water bath dyeing, vat dyeing and multi-bath reactive dyeing, such as simpler process, higher dye utilization, simpler wastewater composition and recyclable ethanol.

[0082] It should be noted that the above embodiments are only for further elaboration and explanation of the technical solution of the present invention, and are not intended to further limit the technical solution of the present invention. The method of the present invention is only a preferred embodiment and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for dyeing nylon, characterized in that, Includes the following steps: A dyeing solution is prepared using reactive dyes and a solvent, wherein the solvent consists of ethanol and water, and the volume percentage of ethanol is not less than 60%. The nylon material to be dyed is added to the dyeing solution for dyeing, forming bath-dyed nylon material; The bath-dyed nylon material is soap-washed to obtain dyed nylon.

2. The nylon dyeing method according to claim 1, characterized in that, The dye solution contains no less than 80% ethanol by volume, the concentration of the reactive dye is 0.2-4% (owf), the dyeing temperature is 60-110℃, and the dyeing time is 5-50 min.

3. The nylon dyeing method according to claim 2, characterized in that, The dye solution contains ethanol at a volume percentage of not less than 80%, the concentration of the reactive dye is 1-4% (owf), the dyeing temperature is 80-110℃, and the dyeing time is 5-20 min.

4. The nylon dyeing method according to claim 3, characterized in that, The dye solution contains ethanol at a volume percentage of not less than 90%, the concentration of the reactive dye is 1-4% (owf), the dyeing temperature is 80-110℃, and the dyeing time is 5-20 min.

5. The nylon dyeing method according to claim 4, characterized in that, The volume percentage of ethanol in the dye solution is not less than 95%, the concentration of the reactive dye is 1~2% (owf), the dyeing temperature is 90~100℃, and the dyeing time is 5~20 min.

6. The nylon dyeing method according to claim 5, characterized in that, The dye solution contains 99% ethanol by volume, the concentration of the reactive dye is 1-2% (owf), the dyeing temperature is 100℃, and the dyeing time is 5-20 min.

7. The nylon dyeing method according to claim 1, characterized in that, The dye solution contains 60-75% ethanol by volume, the reactive dye concentration is 20 g / L, and the dyeing is carried out at 30°C for 24 h.

8. The nylon dyeing method according to any one of claims 1 to 7, characterized in that, The nylon material is at least one of PA6, PA6 blended material, PA56, PA56 blended material, PA66, and PA66 blended material; and / or The reactive dye is selected from at least one of Reactive Blue 20, Reactive Red 195, and Reactive Yellow 145.

9. The nylon dyeing method according to any one of claims 1 to 7, characterized in that, The ethanol in the dye solution can be recovered and reused.

10. The nylon dyeing method according to any one of claims 1 to 6, characterized in that, The soaping step uses a soaping solution containing soap powder and sodium carbonate, with a bath ratio of 1:50, a temperature of 100℃, and a duration of 20 minutes.

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