Superfine polyester yarn coloring method

Abstract

The invention relates to the technical field of dyeing, and particularly discloses a superfine polyester yarn coloring method. A superfine polyester yarn coloring method comprises the following steps that superfine polyester yarn is soaked in pretreatment liquid to be pretreated, taken out and dried; the preparation method comprises the following steps: dissolving sodium lignosulphonate into deionized water, then adding a dye, and grinding and dispersing to obtain a dye body; the method comprises the following steps: adding sodium lignosulphonate and a dye body into deionized water, introducing nitrogen, heating, adding azobis (2-aminopropylamidine) hydrochloride, then slowly adding a mixture of methyl methacrylate and n-butyl acrylate, stirring for reaction, and cooling to obtain a treated dye; immersing the pretreated polyester yarns in a dye solution for dyeing to obtain dyed polyester yarns; wherein the dye liquid comprises the following raw materials: deionized water, a dispersing agent, a cosolvent, a stabilizer, a pH regulator, a treatment dye, a plasticizer, a softening agent, a defoaming agent and a leveling agent; the dyed polyester yarn is immersed in a color fixing agent solution for aftertreatment, and the dyed polyester yarn is obtained.

Description

Technical Field

[0001] The present application relates to the technical field of dyeing, and in particular to a method for dyeing ultrafine polyester yarn. Background Art

[0002] Currently, ultrafine polyester yarn is widely used in high-end clothing fabrics and special-purpose fabrics due to its unique soft feel and good physical properties. However, due to its small fiber diameter and dense structure, it is difficult for traditional dyeing processes to penetrate the fiber, resulting in problems such as insufficient color depth and poor color uniformity.

[0003] Existing improvement measures include increasing dyeing temperature, extending dyeing time and increasing the amount of auxiliaries, but these methods not only increase production costs, but also fail to effectively alleviate environmental pollution. In addition, over-reliance on chemical auxiliaries can also lead to unstable quality of finished products, such as uneven color and easy fading. Summary of the invention

[0004] In order to improve the coloring effect of polyester yarn, the present application provides a method for coloring ultrafine polyester yarn.

[0005] The present application provides a method for coloring ultrafine polyester yarn, which adopts the following technical solution: A method for coloring ultrafine polyester yarn comprises the following steps: Pretreatment: immersing the ultrafine polyester yarn in a pretreatment solution for pretreatment, taking it out, and drying it to obtain the pretreated polyester yarn; Dye treatment: dissolve sodium lignosulfonate in deionized water, then add the dye, grind and disperse to obtain a dye body; add sodium lignosulfonate and the dye body into deionized water, introduce nitrogen, increase the temperature, add azobis(2-aminopropionamidine) hydrochloride, then slowly add a mixture of methyl methacrylate and n-butyl acrylate, stir to react, cool, and obtain a treated dye; Dyeing: immersing the pre-treated polyester yarn in a dye solution for dyeing to obtain a dyed polyester yarn; the raw materials of the dye solution include: deionized water, a dispersant, a cosolvent, a stabilizer, a pH adjuster, a treated dye, a plasticizer, a softener, a defoamer, and a leveling agent; Post-treatment: The dyed polyester yarn is immersed in a fixing agent solution for post-treatment to obtain colored polyester yarn.

[0006] By adopting the above technical scheme, the dye is modified by using sodium lignosulfonate, methyl methacrylate and n-butyl acrylate, so that the dispersion and adhesion properties of the dye are improved. Then, the dye is combined with a dispersant, a cosolvent, a stabilizer, a pH adjuster, a plasticizer, a softener, a defoamer and a leveling agent to form a dye solution, thereby improving the coloring effect on polyester yarn.

[0007] In a specific implementation scheme, the raw materials of the pretreatment liquid include: deionized water, surfactant, dispersant, chelating agent, pH regulator, and the weight ratio of deionized water, surfactant, dispersant, chelating agent, pH regulator is 100: (1-5): (0.5-2): (0.1-0.5): (0.05-0.2).

[0008] By adopting the above technical scheme, the surfactant can reduce the surface tension of the liquid, promote the dye molecules to better penetrate into the fiber, and enhance the affinity between the dye and the fiber; the dispersant helps to prevent the aggregation of dye particles and ensure the uniform distribution of the dye; the chelating agent can effectively remove metal ions in the water and avoid the interference of metal ions in the dyeing process; the pH adjuster can maintain a stable pH environment of the pretreatment liquid and ensure that the various components of the pretreatment liquid can fully play their role, thereby improving the pretreatment effect on the polyester yarn.

[0009] In a specific implementation scheme, the pretreatment step is: filtering the pretreatment liquid using a filter with a pore size of 0.5-2 μm, then immersing the ultrafine polyester yarn in the pretreatment liquid for pretreatment for 10-30 minutes at a temperature of 30-60°C, taking it out, and drying it at 50-80°C for 10-20 minutes to obtain the pretreated polyester yarn.

[0010] By adopting the above technical solution, the pretreatment liquid is filtered before use, and the pore size of the filter is 0.5-2μm, which can effectively remove impurities and large particles in the pretreatment liquid, ensure the purity of the pretreatment liquid, and further limit the pretreatment conditions, thereby improving the coloring uniformity and dyeing quality of the polyester yarn.

[0011] In a specific embodiment, the surfactant in the pre-treatment solution includes one or more of sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and octylphenol polyoxyethylene ether.

[0012] By adopting the above technical scheme, sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and octylphenol polyoxyethylene ether can effectively reduce the interfacial tension between ultrafine polyester yarn and dyes, and enhance the adsorption capacity of dye molecules on the fiber surface, thereby significantly improving the coloring uniformity and color saturation. It also has good wettability and permeability, which helps the dye penetrate deeper into the fiber and further improve the coloring effect.

[0013] In a specific embodiment, the chelating agent in the pre-treatment solution includes one of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and nitrilotriacetic acid.

[0014] By adopting the above technical solution, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and nitrilotriacetic acid can effectively remove metal ions in water and prevent metal ions from having a negative impact on the adsorption of dyes, thereby significantly improving the color uniformity and brightness of ultrafine polyester. At the same time, these chelating agents also have good stability and compatibility, and will not react adversely with other components in the pretreatment solution, ensuring the overall stability of the pretreatment solution.

[0015] In a specific embodiment, the dyeing step is: immersing the pre-treated polyester yarn in the dye solution, performing double immersion and double rolling, and then drying at 55-65° C. for 5-15 minutes to obtain the dyed polyester yarn.

[0016] By adopting the above technical solution, the dyeing temperature and time are further limited, thereby improving the coloring effect on the polyester yarn.

[0017] In a specific embodiment, the dispersant in the dye solution includes one or more of sodium polyacrylate, polyethylene glycol, polyvinyl alcohol, sodium alkylbenzene sulfonate, and alkylphenol polyoxyethylene ether.

[0018] In a specific embodiment, the plasticizer in the dye liquor comprises phthalate.

[0019] In a specific embodiment, the softener in the dye solution includes one or more of ditallow dimethyl ammonium chloride, dihexadecyl dimethyl ammonium chloride, and dioctadecyl dimethyl ammonium chloride.

[0020] In a specific embodiment, the leveling agent in the dye solution includes one or more of polysorbate 80, peregal O, and octylphenol polyoxyethylene ether.

[0021] By adopting the above technical scheme, polysorbate 80, perchlorethylene O, and octylphenol polyoxyethylene ether can improve the fluidity of the dye solution and reduce the color unevenness caused by excessive local concentration during the dyeing process, thereby ensuring that the color of the dyed polyester fiber is more uniform and consistent; at the same time, these leveling agents also have good permeability and dispersibility, which helps the dye molecules to be more evenly distributed inside the fiber, further improving the dyeing effect.

[0022] In summary, the present application includes at least one of the following beneficial technical effects: 1. In the present application, sodium lignosulfonate, methyl methacrylate and n-butyl acrylate are used to modify the dye, thereby improving the dispersion and adhesion properties of the dye, and then the dye is combined with a dispersant, a cosolvent, a stabilizer, a pH regulator, a plasticizer, a softener, a defoamer and a leveling agent to form a dye solution, thereby improving the coloring effect on polyester yarn; 2. In the pretreatment liquid of the present application, the surfactant can reduce the surface tension of the liquid, promote the better penetration of dye molecules into the fiber, and enhance the affinity between the dye and the fiber; the dispersant helps to prevent the aggregation of dye particles and ensure the uniform distribution of the dye; the chelating agent can effectively remove metal ions in the water to avoid the interference of metal ions in the dyeing process; the pH regulator can maintain a stable pH environment of the pretreatment liquid and ensure that the various components of the pretreatment liquid can fully play their role, thereby improving the pretreatment effect on the polyester yarn; 3. In the present application, the pretreatment liquid is filtered before use, and the pore size of the filter is 0.5-2μm, which can effectively remove impurities and large particles in the pretreatment liquid, ensure the purity of the pretreatment liquid, and further limit the pretreatment conditions, thereby improving the coloring uniformity and dyeing quality of the polyester yarn. DETAILED DESCRIPTION

[0023] The present application is further described in detail below with reference to the embodiments.

[0024] All raw materials in the embodiment can be obtained commercially. The surfactant in the pretreatment liquid includes but is not limited to a mixture of one or more of sodium dodecyl sulfate, hexadecyl trimethyl ammonium bromide, and octylphenol polyoxyethylene ether, preferably sodium dodecyl sulfate in this application; the chelating agent in the pretreatment liquid includes but is not limited to a mixture of one or more of ethylenediaminetetraacetic acid, diethylenetriamine pentaacetic acid, and nitrilotriacetic acid, preferably ethylenediaminetetraacetic acid in this application; the dispersant in the dye solution includes but is not limited to a mixture of one or more of sodium polyacrylate, polyethylene glycol, polyvinyl alcohol, sodium alkylbenzene sulfonate, and alkylphenol polyoxyethylene ether, preferably in this application Sodium polyacrylate is selected; the softener in the dye solution includes but is not limited to a mixture of one or more of ditallow dimethyl ammonium chloride, dihexadecyl dimethyl ammonium chloride, and dioctadecyl dimethyl ammonium chloride, and ditallow dimethyl ammonium chloride is preferred in the present application; the leveling agent in the dye solution includes but is not limited to a mixture of one or more of polysorbate 80, peregal O, and octylphenol polyoxyethylene ether, and peregal O is preferred in the present application; the dye includes but is not limited to a mixture of one or more of disperse violet 93, disperse blue 79, disperse red 60, and disperse yellow 33, and disperse violet 93 is preferred in the present application.

[0025] Preparation Example Preparation Example 1 Preparation Example 1 provides a method for preparing a pretreatment solution, comprising the following steps: Add a surfactant, a dispersant, a chelating agent and a pH regulator into deionized water, stir and mix evenly to obtain a pretreatment solution: wherein the weight ratio of deionized water, the surfactant, the dispersant, the chelating agent and the pH regulator is 100:1:0.5:0.1:0.05; the surfactant is sodium dodecyl sulfate; the dispersant is sodium polyacrylate; the chelating agent is ethylenediaminetetraacetic acid; and the pH regulator is citric acid.

[0026] Preparation Example 2 Preparation Example 2 provides a method for preparing a pretreatment solution, comprising the following steps: Add a surfactant, a dispersant, a chelating agent, and a pH regulator into deionized water, stir and mix evenly, and obtain a pretreatment solution: wherein the weight ratio of deionized water, the surfactant, the dispersant, the chelating agent, and the pH regulator is 100:3:1.5:0.3:0.1; the surfactant is sodium dodecyl sulfate; the dispersant is sodium polyacrylate; the chelating agent is ethylenediaminetetraacetic acid; and the pH regulator is citric acid.

[0027] Preparation Example 3 Preparation Example 3 provides a method for preparing a pretreatment solution, comprising the following steps: Add a surfactant, a dispersant, a chelating agent, and a pH regulator into deionized water, stir and mix evenly, and obtain a pretreatment solution: wherein the weight ratio of deionized water, the surfactant, the dispersant, the chelating agent, and the pH regulator is 100:5:2:0.5:0.2; the surfactant is sodium dodecyl sulfate; the dispersant is sodium polyacrylate; the chelating agent is ethylenediaminetetraacetic acid; and the pH regulator is citric acid.

[0028] Preparation Example 4 Preparation Example 4 provides a method for preparing a dye solution, comprising the following steps: Dissolve sodium lignosulfonate in deionized water, add dye under stirring, and then grind and disperse at a speed of 3500r / min for 2h using a grinder to obtain a dye body; wherein the weight ratio of sodium lignosulfonate to deionized water is 1:5; the dye is disperse violet 93; Add sodium lignosulfonate and dye body to deionized water, introduce nitrogen, heat to 70°C, add azobis(2-aminopropionamidine) hydrochloride during stirring, then slowly add a mixture of methyl methyl ester and n-butyl acrylate, stir and react at 70°C for 11.5h, cool to room temperature, and obtain a treated dye; wherein the weight ratio of sodium lignosulfonate, dye body, deionized water, azobis(2-aminopropionamidine) hydrochloride, methyl methyl ester and n-butyl acrylate is 1:10:35:0.06:1:1; Add dispersant, cosolvent, stabilizer, pH regulator, treated dye, plasticizer, softener, defoamer and leveling agent into deionized water, stir and mix evenly to obtain dye solution; wherein the weight ratio of deionized water, dispersant, cosolvent, stabilizer, pH regulator, treated dye, plasticizer, softener, defoamer and leveling agent is 100:3:2:0.5:0.1:3:0.5:0.2:0.3:0.3; the dispersant is sodium polyacrylate; the cosolvent is ethylene glycol; the stabilizer is sodium citrate; the pH regulator is sodium hydroxide; the plasticizer is phthalate; the softener is ditallow dimethyl ammonium chloride; the defoamer is a silicone defoamer, model number is wh25056; the leveling agent is peregrin O.

[0029] Preparation Example 5 Preparation Example 5 provides a method for preparing a dye solution, comprising the following steps: Dispersant, cosolvent, stabilizer, pH regulator, dye, plasticizer, softener, defoamer and leveling agent are added into deionized water, stirred and mixed evenly to obtain dye solution; wherein the weight ratio of deionized water, dispersant, cosolvent, stabilizer, pH regulator, treated dye, plasticizer, softener, defoamer and leveling agent is 100:3:2:0.5:0.1:3:0.5:0.2:0.3:0.3; the dispersant is sodium polyacrylate; the cosolvent is ethylene glycol; the stabilizer is sodium citrate; the pH regulator is sodium hydroxide; the plasticizer is phthalate; the softener is ditallow dimethyl ammonium chloride; the defoamer is a silicone defoamer with model number wh25056; the leveling agent is peregrin O; and the dye is disperse violet 93.

[0030] Preparation Example 6 Preparation Example 6 provides a method for preparing a color fixing agent solution, comprising the following steps: Cetylpyridinium chloride is added into deionized water, and the mixture is stirred and mixed to obtain a color fixing agent solution; wherein the mass concentration of cetylpyridinium chloride in the color fixing agent solution is 1%. Example

[0031] Example 1 Embodiment 1 provides a method for coloring ultrafine polyester yarn, comprising the following steps: Pretreatment: Filter the pretreatment solution in Preparation Example 1 using a filter with a pore size of 0.5-2 μm, then immerse the ultrafine polyester yarn in the pretreatment solution for pretreatment for 10 minutes, with a bath ratio of 1:12.5 and a temperature of 60°C, take it out, and dry it at 50°C for 20 minutes to obtain the pretreated polyester yarn; Dyeing: Immerse the pre-treated polyester yarn in the dye solution prepared in Example 4 at a bath ratio of 1:20. The yarn was double dipped and double rolled, with a liquid rate of 58%, and then dried at 55°C for 15 minutes to obtain dyed polyester yarn; Post-treatment: The dyed polyester yarn was immersed in the fixing agent solution in Preparation Example 6 for post-treatment for 20 minutes, with a bath ratio of 1:10 and a temperature of 50°C to obtain a colored polyester yarn.

[0032] Example 2 Embodiment 2 provides a method for coloring ultrafine polyester yarn, comprising the following steps: Pretreatment: Filter the pretreatment solution in Preparation Example 2 using a filter with a pore size of 0.5-2 μm, then immerse the ultrafine polyester yarn in the pretreatment solution for pretreatment for 10 minutes, with a bath ratio of 1:12.5 and a temperature of 60°C, take it out, and dry it at 50°C for 20 minutes to obtain the pretreated polyester yarn; Dyeing: Immerse the pre-treated polyester yarn in the dye solution prepared in Example 4 at a bath ratio of 1:20. The yarn was double dipped and double rolled, with a liquid rate of 58%, and then dried at 55°C for 15 minutes to obtain dyed polyester yarn; Post-treatment: The dyed polyester yarn was immersed in the fixing agent solution in Preparation Example 6 for post-treatment for 20 minutes, with a bath ratio of 1:10 and a temperature of 50°C to obtain a colored polyester yarn.

[0033] Example 3 Embodiment 3 provides a method for coloring ultrafine polyester yarn, comprising the following steps: Pretreatment: Filter the pretreatment solution in Preparation Example 3 using a filter with a pore size of 0.5-2 μm, then immerse the ultrafine polyester yarn in the pretreatment solution for pretreatment for 10 minutes, the bath ratio is 1:12.5, the temperature is 60°C, take it out, and dry it at 50°C for 20 minutes to obtain the pretreated polyester yarn; Dyeing: Immerse the pre-treated polyester yarn in the dye solution prepared in Example 4 at a bath ratio of 1:20. The yarn was double dipped and double rolled, with a liquid rate of 58%, and then dried at 55°C for 15 minutes to obtain dyed polyester yarn; Post-treatment: The dyed polyester yarn was immersed in the fixing agent solution in Preparation Example 6 for post-treatment for 20 minutes, with a bath ratio of 1:10 and a temperature of 50°C to obtain a colored polyester yarn.

[0034] Example 4 Embodiment 4 provides a method for coloring ultrafine polyester yarn, comprising the following steps: Pretreatment: Filter the pretreatment solution in Preparation Example 2 using a filter with a pore size of 0.5-2 μm, then immerse the ultrafine polyester yarn in the pretreatment solution for pretreatment for 20 minutes, with a bath ratio of 1:12.5 and a temperature of 45°C, take it out, and dry it at 65°C for 15 minutes to obtain the pretreated polyester yarn; Dyeing: Immerse the pre-treated polyester yarn in the dye solution prepared in Example 4 at a bath ratio of 1:20. The yarn was double dipped and double rolled, with a liquid rate of 58%, and then dried at 55°C for 15 minutes to obtain dyed polyester yarn; Post-treatment: The dyed polyester yarn was immersed in the fixing agent solution in Preparation Example 6 for post-treatment for 20 minutes, with a bath ratio of 1:10 and a temperature of 50°C to obtain a colored polyester yarn.

[0035] Example 5 Embodiment 5 provides a method for coloring ultrafine polyester yarn, comprising the following steps: Pretreatment: Filter the pretreatment solution in Preparation Example 2 using a filter with a pore size of 0.5-2 μm, then immerse the ultrafine polyester yarn in the pretreatment solution for pretreatment for 30 minutes, with a bath ratio of 1:12.5 and a temperature of 30°C, take it out, and dry it at 80°C for 10 minutes to obtain the pretreated polyester yarn; Dyeing: Immerse the pre-treated polyester yarn in the dye solution prepared in Example 4 at a bath ratio of 1:20. The yarn was double dipped and double rolled, with a liquid rate of 58%, and then dried at 55°C for 15 minutes to obtain dyed polyester yarn; Post-treatment: The dyed polyester yarn was immersed in the fixing agent solution in Preparation Example 6 for post-treatment for 20 minutes, with a bath ratio of 1:10 and a temperature of 50°C to obtain a colored polyester yarn.

[0036] Example 6 Embodiment 6 provides a method for coloring ultrafine polyester yarn, comprising the following steps: Pretreatment: Filter the pretreatment solution in Preparation Example 2 using a filter with a pore size of 0.5-2 μm, then immerse the ultrafine polyester yarn in the pretreatment solution for pretreatment for 20 minutes, with a bath ratio of 1:12.5 and a temperature of 45°C, take it out, and dry it at 65°C for 15 minutes to obtain the pretreated polyester yarn; Dyeing: Immerse the pre-treated polyester yarn in the dye solution prepared in Example 4 at a bath ratio of 1:20. The dyed polyester yarn was obtained by double dipping and double rolling, with a liquid carrying rate of 58%, and then drying at 60°C for 10 minutes; Post-treatment: The dyed polyester yarn was immersed in the fixing agent solution in Preparation Example 6 for post-treatment for 20 minutes, with a bath ratio of 1:10 and a temperature of 50°C to obtain a colored polyester yarn.

[0037] Example 7 Embodiment 7 provides a method for coloring ultrafine polyester yarn, comprising the following steps: Pretreatment: Filter the pretreatment solution in Preparation Example 2 using a filter with a pore size of 0.5-2 μm, then immerse the ultrafine polyester yarn in the pretreatment solution for pretreatment for 20 minutes, with a bath ratio of 1:12.5 and a temperature of 45°C, take it out, and dry it at 65°C for 15 minutes to obtain the pretreated polyester yarn; Dyeing: Dyeing: The pretreated polyester yarn is immersed in the dye solution in Preparation Example 4, with a bath ratio of 1:20, and double-immersion and double-rolling are performed, with a liquid rate of 58%, followed by drying at 65°C for 5 minutes to obtain a dyed polyester yarn; Post-treatment: The dyed polyester yarn was immersed in the fixing agent solution in Preparation Example 6 for post-treatment for 20 minutes, with a bath ratio of 1:10 and a temperature of 50°C to obtain a colored polyester yarn.

[0038] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that, dyeing: the pretreated polyester yarn is immersed in the dye solution in Preparation Example 5, the bath ratio is 1:20, and two immersions and two rollings are performed, the liquid carrying rate is 58%, and then baked at 55°C for 15 minutes to obtain dyed polyester yarn; the remaining steps are consistent with Example 1.

[0039] Performance testing of coloring effect: Test the washing fastness, sunlight fastness and K / S value of polyester yarn. The higher the washing fastness and sunlight fastness levels, the better the coloring effect of the polyester yarn. The higher the K / S value, the darker the color of the polyester yarn. The lower the K / S value, the brighter the brightness of the polyester yarn.

[0040] Table 1 Performance test results of polyester yarn sample Soap fastness Light fastness K / S value Example 1 5 4 3.9 Example 2 5 5 4.3 Example 3 5 4 4.1 Example 4 5 6 4.6 Example 5 5 5 4.4 Example 6 5 6 4.7 Example 7 5 6 4.7 Comparative Example 1 4 2 3.2 Combining Example 1 and Comparative Example 1, the coloring effect of the polyester yarn in Example 1 is better. It can be seen that using the coloring method in the present application, the polyester yarn is first pre-treated, and then the dye is modified using sodium lignosulfonate, methyl methacrylate, and n-butyl acrylate to improve the dispersion and adhesion properties of the dye, and then combined with a dispersant, a solvent, a stabilizer, a pH adjuster, a plasticizer, a softener, a defoamer, and a leveling agent to form a dye solution to color the polyester yarn, and finally a color fixing treatment is performed, thereby improving the coloring effect of the polyester yarn.

[0041] In combination with Examples 1-3, the coloring effect of the polyester yarn in Example 2 is the best. It can be seen that when preparing the pretreatment solution, the ratio of deionized water, surfactant, dispersant, chelating agent, and pH adjuster in Preparation Example 2 is optimal, thereby obtaining the best treatment effect of the pretreatment solution.

[0042] Combining Example 2, Example 4 and Example 5, the coloring effect of the polyester yarn in Example 4 is the best. It can be seen that when the polyester yarn is pretreated with the pretreatment liquid, the treatment conditions in Example 4 are the best.

[0043] Combining Example 4, Example 6 and Example 7, it can be seen that when dyeing, the drying conditions in Example 4, Example 6 and Example 7 are better, so the coloring effect on the polyester yarn is better.

[0044] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for coloring ultrafine polyester yarn, characterized in that: The following steps are involved: Pretreatment: immersing the ultrafine polyester yarn in a pretreatment solution for pretreatment, taking it out, and drying it to obtain the pretreated polyester yarn; Dye treatment: dissolve sodium lignosulfonate in deionized water, then add dye, grind and disperse to obtain dye body; add sodium lignosulfonate and dye body into deionized water, introduce nitrogen, increase the temperature, add azobis(2-aminopropionamidine) hydrochloride, then slowly add a mixture of methyl methacrylate and n-butyl acrylate, stir to react, cool, and obtain treated dye; Dyeing: immersing the pre-treated polyester yarn in a dye solution for dyeing to obtain dyed polyester yarn; The raw materials of the dye solution include: deionized water, dispersant, cosolvent, stabilizer, pH adjuster, treated dye, plasticizer, softener, defoamer, leveling agent; Post-treatment: The dyed polyester yarn is immersed in a fixing agent solution for post-treatment to obtain colored polyester yarn.

2. The method for coloring ultrafine polyester yarn according to claim 1, characterized in that: The raw materials of the pretreatment liquid include: deionized water, surfactant, dispersant, chelating agent, pH regulator, and the weight ratio of deionized water, surfactant, dispersant, chelating agent, pH regulator is 100: (1-5): (0.5-2): (0.1-0.5): (0.05-0.2).

3. The method for coloring superfine polyester yarn according to claim 2, characterized in that: The pretreatment step is: filtering the pretreatment liquid with a filter screen with a pore size of 0.5-2 μm, then immersing the ultrafine polyester yarn in the pretreatment liquid for pretreatment for 10-30 minutes at a temperature of 30-60° C., taking it out, and drying it at 50-80° C. for 10-20 minutes to obtain the pretreated polyester yarn.

4. The method for coloring ultrafine polyester yarn according to claim 2, characterized in that: The surfactant in the pretreatment solution includes one or more of sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and octylphenol polyoxyethylene ether.

5. The method for coloring superfine polyester yarn according to claim 2, characterized in that: The chelating agent in the pretreatment solution includes one of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid and nitrilotriacetic acid.

6. The method for coloring superfine polyester yarn according to claim 1, characterized in that: The dyeing step comprises: immersing the pre-treated polyester yarn in the dye solution, performing double immersion and double rolling, and then drying at 55-65° C. for 5-15 minutes to obtain the dyed polyester yarn.

7. A method for coloring ultrafine polyester yarn according to claim 6, characterized in that: The dispersant in the dye solution includes one or more of sodium polyacrylate, polyethylene glycol, polyvinyl alcohol, sodium alkylbenzene sulfonate, and alkylphenol polyoxyethylene ether.

8. The method for coloring superfine polyester yarn according to claim 6, characterized in that: The plasticizer in the dye solution includes phthalates.

9. The method for coloring superfine polyester yarn according to claim 6, characterized in that: The softener in the dye solution includes one or more of ditallow dimethyl ammonium chloride, dihexadecyl dimethyl ammonium chloride, and dioctadecyl dimethyl ammonium chloride.

10. The method for coloring superfine polyester yarn according to claim 6, characterized in that: The leveling agent in the dye solution includes one or more of polysorbate 80, peregal O, and octylphenol polyoxyethylene ether.