Nylon rapid dyeing leveling agent and preparation method and application thereof

Abstract

The invention discloses a nylon rapid dyeing leveling agent and a preparation method and application thereof. The leveling agent comprises water and the following preparation raw materials in percentage by mass: 30-40% of fatty amine polyoxyethylene ether; 2%-10% of succinic anhydride; 0.4%-1% of urea; 5%-10% of castor oil polyoxyethylene ether; 1%-3% of sodium hydroxide; and 2%-6% of a benzotriazole ultraviolet light absorber. The leveling agent has excellent dyeing performance, especially has excellent retarding performance and migration performance, and can realize rapid dyeing and improve the dyeing efficiency. The invention also provides a preparation method and application of the leveling agent.

Description

Technical Field

[0001] The invention relates to the technical field of dyeing auxiliaries, and in particular to a nylon rapid dyeing leveling agent and a preparation method and application thereof. Background Art

[0002] Nylon, or nylon fiber, has good wear resistance, high strength and excellent elasticity. Nylon fiber fabrics are not only light and wrinkle-resistant, but are also widely used in the textile field. However, due to the high crystallinity and relative hydrophobicity of nylon fiber structure, it is difficult to dye nylon, and the requirements for dyeing technology are more stringent.

[0003] In the traditional nylon dyeing process, acid leveling agents are usually used in combination with acid-releasing agents as a buffer system to stabilize the pH value in the dye bath and ensure the dye uptake and dyeing uniformity of nylon fibers. However, there are still many problems with existing nylon leveling agents in practical applications: some leveling agents have a high resistance to fiber dyeing, resulting in unsatisfactory dye uptake and light color; other leveling agents, although they have good affinity for dyes and fibers, require slow heating to control the dyeing process to ensure dyeing uniformity and quality, which makes the dyeing time too long, energy consumption high and the fabric quality unstable.

[0004] Therefore, it is urgent to develop a leveling agent that can achieve rapid dyeing and ensure dyeing effect. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a nylon rapid dyeing leveling agent, which has excellent dyeing performance, especially excellent performance in slow dyeing and dyeing migration, and can achieve rapid dyeing, effectively improving the dyeing efficiency of nylon-containing fabrics.

[0006] The present invention also provides a preparation method using the leveling agent.

[0007] The present invention also provides application of the above-mentioned leveling agent.

[0008] Specifically, the first embodiment of the present invention relates to a leveling agent, comprising water and the following raw materials in percentage by mass:

[0009] Fatty amine polyoxyethylene ether 30%-40%;

[0010] Succinic anhydride 2%-10%;

[0011] Urea 0.4%-1%;

[0012] Castor oil polyoxyethylene ether 5%-10%;

[0013] Sodium hydroxide 1%-3%;

[0014] Benzotriazole UV absorber 2%-6%;

[0015] The fatty amine polyoxyethylene ether and succinic anhydride react to form an amide compound.

[0016] The leveling agent according to the first embodiment of the present invention has at least the following beneficial effects:

[0017] Fatty amine polyoxyethylene ether can react with succinic anhydride to generate amidation products (succinic anhydride has high reactivity and easily undergoes nucleophilic reaction with -NH2. It can react quickly and efficiently under milder conditions to generate amidation products with fewer by-products), and further form fatty amine polyoxyethylene ether succinic acid sodium salt in the presence of alkali (the introduction of urea can effectively promote this reaction). The compound salt shows good affinity for fibers and can significantly improve the solubility of acid dyes. In the initial stage of dyeing, the dyeing rate of acid dyes can be effectively suppressed, ensuring the slow dyeing effect during the dyeing process and significantly improving the uniformity of dyeing.

[0018] Castor oil polyoxyethylene ether has good solubility and dispersion ability for dyes. During the rapid dyeing and heating process, it can ensure the one-time success rate of nylon fabric dyeing. It not only ensures the high efficiency and uniformity of dyeing, but also significantly reduces energy consumption and improves production efficiency while maintaining good dyeing effects.

[0019] Benzotriazole UV absorbers can occupy the NH 3+ site (the amino groups on nylon fibers are protonated to positively charged NH 3+ , these sites are easy to adsorb negatively charged acid dyes), further enhancing the slow dyeing properties, improving the dyeing effect, and enhancing the dyeing durability.

[0020] In summary, this formula successfully achieved a comprehensive improvement in dyeing uniformity and efficiency in the nylon dyeing process through the synergistic effect of various components.

[0021] According to some embodiments of the present invention, the average number of EO segments in the fatty amine polyoxyethylene ether molecule is 12-18, for example, specifically 12, 13, 14, 15, 16, 17 or 18. The average number of EO segments represents the average number of EO units in each molecule.

[0022] The number of EO segments in the fatty amine polyoxyethylene ether is controlled to have moderate hydrophilicity and hydrophobicity, so as to have good water solubility and adsorption to fibers, and improve the uniformity of dyeing. If the number of EO is too low, the lipophilicity will be enhanced, resulting in reduced water solubility, and the improvement of the dispersion and uniformity of the dye is limited. On the contrary, if the number of EO is too high, the hydrophilicity increases, which may affect its adhesion to the fiber.

[0023] The present invention does not impose any restriction on the number of carbon atoms of the fatty amine in the fatty amine polyoxyethylene ether, for example, it can be 16 to 20.

[0024] According to some embodiments of the present invention, the average number of EO segments in the castor oil polyoxyethylene ether molecule is 20-60, for example, specifically 20, 25, 30, 35, 40, 45, 50, 55 or 60. The number of EO segments in the castor oil polyoxyethylene ether is controlled within the above range to achieve a better hydrophilic-lipophilic balance, improve the solubility and dispersion of the dye, ensure good adhesion of the dye to the fiber, achieve a stable and uniform dyeing effect, and improve the dyeing efficiency.

[0025] According to some embodiments of the present invention, the average number of EO segments in the castor oil polyoxyethylene ether molecule is 30-60, for example, 30-40, or 40-60, etc.

[0026] According to some embodiments of the present invention, the mass percentage of the fatty amine polyoxyethylene ether is 30%-35%, specifically about 30%, 31%, 32%, 33%, 34% or 35%. "About" indicates the value after conventional rounding.

[0027] According to some embodiments of the present invention, the mass percentage of the fatty amine polyoxyethylene ether is 30%-32%.

[0028] According to some embodiments of the present invention, the mass percentage of succinic anhydride is 2%-5%, for example, 3%-5%, or 2%-4%, more specifically, about 2%, 3%, 4% or 5%.

[0029] According to some embodiments of the present invention, the mass percentage of urea is 0.4%-0.8%, for example, specifically about 0.4%, 0.5%, 0.6%, 0.7% or 0.8%.

[0030] According to some embodiments of the present invention, the molar ratio of the fatty amine polyoxyethylene ether, succinic anhydride, and urea is 1:0.8-1.5:0.1-0.4, for example, 1:0.8-1:0.1-0.4, or 1:0.8-1:0.1-0.3, more specifically about 1:0.8:0.1, 1:0.8:0.2, 1:0.8:0.3, 1:0.8:0.4, 1:0.9:0.1, 1:0.9:0.2, 1:0.9:0.3, 1:0.9:0.4, 1:1:0.1, 1:1:0.2, 1:1:0.3, 1:1:0.4, etc. The control group distribution ratio is within the above range, which is conducive to achieving full reaction under mild conditions and ensuring reaction efficiency and product quality.

[0031] According to some embodiments of the present invention, the benzotriazole ultraviolet absorber is selected from hydroxyphenylbenzotriazole ultraviolet absorbers, such as the commercially available brand UV-1130, which has better compatibility than other benzotriazole ultraviolet absorbers and can achieve a more stable and uniform dispersion effect.

[0032] According to some embodiments of the present invention, the reaction temperature is 80-120°C, and the reaction time is 1-4h. The reaction process has the advantages of rapid reaction, mild conditions and few side reactions. Specifically, the reaction temperature can be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, and the reaction time can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h. The reaction conditions can be flexibly selected within the temperature and time ranges listed above to meet the process requirements.

[0033] According to some embodiments of the present invention, the pH of the leveling agent is 6-8.

[0034] According to some embodiments of the present invention, the mass percentage of water in the leveling agent is ≥50%. The present invention does not limit the water content in the dye, and the water content can be selected according to actual needs and experience.

[0035] The second embodiment of the present invention relates to a method for preparing the aforementioned leveling agent, comprising the following steps: reacting the fatty amine polyoxyethylene ether and succinic anhydride in the presence of the urea to form an amide compound; and mixing the amide compound with the remaining preparation raw materials.

[0036] This method is easy to operate and suitable for large-scale application.

[0037] According to some embodiments of the present invention, the amide compound is mixed with other preparation raw materials, including: mixing the amide compound with preparation raw materials including water, castor oil polyoxyethylene ether, and benzotriazole ultraviolet absorber, and then adding sodium hydroxide to mix.

[0038] This method is conducive to uniform mixing of the components and improves their dispersibility and stability.

[0039] According to some embodiments of the present invention, the reaction temperature is 80-120° C., and the reaction time is 1-4 h.

[0040] A third aspect of the present invention relates to the use of the above-mentioned leveling agent in dyeing nylon-containing fabrics.

[0041] Since the leveling agent of the present invention has zwitterionic properties and good dye solubility and dispersion properties, it is particularly suitable for use in the nylon dyeing process. Its unique properties can improve the adsorption uniformity of the dye, significantly enhance the dyeing uniformity and slow dyeing effect, and increase the one-time success rate of dyeing, while effectively reducing energy consumption.

[0042] According to some embodiments of the present invention, the heating rate of dyeing is 1.5-3°C / min, specifically 1.5°C / min, 2.0°C / min, 2.5°C / min and 3.0°C / min. A gradient heating method can be adopted, for example, a relatively higher heating rate (such as 2.5°C / min or 3.0°C / min) is selected in the early stage, and a relatively lower heating rate (such as 1.5°C / min or 2.0°C / min) is selected in the later stage to better balance the efficiency and dyeing effect.

[0043] In order to ensure the dyeing effect, conventional dyes usually control the heating rate below 1°C / min, especially in the initial heating stage, the heating rate is usually significantly lower than 1°C / min, for example, 0.6-0.7°C / min. Therefore, this solution significantly improves the dyeing efficiency while ensuring the dyeing effect, and has higher production benefits compared to conventional leveling agents.

[0044] According to some embodiments of the present invention, the dyeing adopts a gradient heating method, including a first heating stage and a second heating stage, wherein the temperature range of the first heating stage is 40-60°C, the temperature range of the second heating stage is 60°C-100°C, and the heating rate of the first stage is greater than the heating rate of the second stage. For example, the heating rate of the first stage is 2.5-3°C / min, and the heating rate of the second stage is 1.5-2°C / min.

[0045] According to some embodiments of the present invention, the nylon-containing fabric includes pure nylon fabric, nylon blended fabric or nylon interwoven fabric. Among them, the nylon blended fabric includes nylon-polyester blend (nylon and polyester blend), nylon-cotton blend (nylon and cotton blend), nylon-wool blend (nylon and wool blend), and nylon-spandex blend (nylon and spandex blend). For non-pure nylon fabric, the content ratio of nylon is not specifically limited and can be selected according to industry experience. The present invention does not limit the fabric form and is applicable to knitted, woven and other fabric types.

[0046] Herein, the numerical ranges involved include the endpoint values ​​and cover any sub-ranges within the range, such as the ranges obtained by any combination of the specifically listed values. In addition, "above" or "below" includes the values ​​themselves.

[0047] "Room temperature" refers to 23±2°C.

[0048] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practicing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The effects of the leveling agents of Inventive Example 1 and Comparative Example 3 in the dye dispersion test are shown.

[0050] Figure 2 The figure is a comparison of the temperature rise and fall curves of the dyeing process of the embodiment of the present invention and the conventional dyeing process during the cloth dyeing process.

[0051] Figure 3 The following is a comparison of the dyeing effects of the leveling agents of Example 1 of the present invention and Comparative Example 5.

[0052] Figure 4 These are the test results of the slow dyeing properties of the leveling agents of Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 5 on knitted fabrics of the present invention.

[0053] Figure 5 The slow dyeing test results of the leveling agents of Examples 1, 2, 3 of the present invention and Comparative Example 5 on knitted fabrics are shown.

[0054] Figure 6 The test results of the slow dyeing properties of the leveling agents of Examples 1, 2, 3 of the present invention and Comparative Example 5 on woven fabrics are shown.

[0055] Figure 7 The slow dyeing test results of the leveling agents of Examples 1, 4, 5 of the present invention and Comparative Example 5 on knitted fabrics are shown.

[0056] Figure 8 The slow dyeing test results of the leveling agents of Examples 1, 6, 7 of the present invention and Comparative Example 4 on knitted fabrics are shown.

[0057] Fig. 9 The test results of dye migration of the leveling agent of Examples 1, 4, 5 of the present invention and Comparative Example 5 on knitted fabrics are shown. DETAILED DESCRIPTION

[0059] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0060] In the following examples, some of the raw materials are described as follows:

[0061] Benzotriazole ultraviolet absorber: UV-1130, purchased from Tianjin Lianlong.

[0062] Fatty amine polyoxyethylene ether: octadecylamine polyoxyethylene ether.

[0063] Unless otherwise specified, the raw materials or equipment involved are commercially available conventional products.

[0064] Example 1

[0065] A leveling agent was prepared, and the weight proportions of the raw materials were as follows: 35% in total of fatty amine polyoxyethylene ether, succinic anhydride, and urea (molar ratio 1:0.8:0.2), 2% sodium hydroxide, 5% castor oil polyoxyethylene ether, 4% benzotriazole ultraviolet absorber, and 54% deionized water.

[0066] The preparation process of the leveling agent is as follows:

[0067] According to the ratio, fatty amine polyoxyethylene ether and succinic anhydride are put into the reactor, urea is added as a catalyst, the temperature is raised to 105°C, and the reaction is kept warm for 2 hours to synthesize fatty amine polyoxyethylene ether succinamide. The temperature is lowered to 60°C, castor oil polyoxyethylene ether, triazole ultraviolet absorber and deionized water are added, stirred for 30-40 minutes, and finally sodium hydroxide is added to adjust the pH to 6.0-8.0.

[0068] Embodiment 2-7

[0069] A leveling agent was prepared, which differed from Example 1 only in the different raw materials used for preparation, as shown in Table 1.

[0070] Comparative Examples 1-4

[0071] A leveling agent was prepared, which differed from Example 1 only in the different raw materials used for preparation, as shown in Table 1.

[0072] Comparative Example 5

[0073] Commercially available conventional leveling agent, purchased from Tuona Chemical, main ingredients: fatty amine, sodium dodecylbenzene sulfonate.

[0074] Table 1

[0075]

[0076] In Table 1, "FAE" stands for fatty amine polyoxyethylene ether (Fatty Amine Polyethylene Glycol Ether), and "COE" stands for castor oil polyoxyethylene ether (Castor Oil Ethoxylate).

[0077] Test Case

[0078] The relevant dye formulas and tested fabrics are shown in Table 2, where the reactive dyes were purchased from Archroma.

[0079] Table 2

[0080]

[0081] 1. Dye dispersion

[0082] Prepare red dye (red MB 0.6% owf, HAC 0.3 g / L) and use 1% owf of leveling agent, and filter.

[0083] The color of the filter paper after filtration is Figure 1 As shown, Figure 1 The left side is the leveling agent of Example 1, and the right side is the leveling agent of Comparative Example 3. It can be seen that castor oil polyoxyethylene ether is not added in Comparative Example 3, resulting in obvious agglomeration of the dye, and the filtration time is significantly increased, indicating that its leveling agent is difficult to effectively disperse the dye. It is difficult to ensure dyeing uniformity after dye agglomeration, so it is not industrially available and no subsequent dyeing effect test is performed. The dye performance of the remaining embodiments is the same as that of Example 1, and is not repeated.

[0084] 2. Cloth effect

[0085] Gray and brilliant blue dyes were prepared according to the ratios in Table 2. A leveling agent (1% owf) was added to the dyes. Taking Example 1 and Comparative Example 5 as examples, Figure 2 The specific operation is as follows: dyeing is carried out at 40℃, heating up to 60℃ at a heating rate of 3℃ / min, when the temperature reaches 60℃, heating up to 98℃ at a heating rate of 1.5℃ / min, keeping at 98℃ for 30min, adding 0.3g / L glacial acetic acid during the heating period, and cooling down to 60℃ at a cooling rate of 1.5℃ / min after the heating ends.

[0086] The effect after dyeing is as follows Figure 3 As shown. It can be seen that the leveling agent of Example 1 dyes the fabric evenly, with full color and no obvious mismatch and step difference. However, the leveling agent of Comparative Example 5 shows slight color fringing on the fabric of gray dye and moderate color fringing on the fabric of brilliant blue dye under the rapid dyeing process. In order to achieve a comparable dyeing effect, Comparative Example 5 needs to use Figure 2 b) is used for dyeing at the conventional heating and cooling rate (1% owf of leveling agent and 0.5 g / L of acid-releasing agent are added to the dye), and the specific operation is as follows: dyeing at 40°C, heating to 60°C at a heating rate of 0.7°C / min, keeping at 60°C for 10 min, then heating to 70°C at a heating rate of 1°C / min, keeping at 70°C for 10 min, then heating to 98°C at a heating rate of 1°C / min, keeping at 98°C for 30 min, and after the end of the insulation, cooling to 60°C at a cooling rate of 1.5°C / min. Obviously, the dyeing efficiency of the leveling agent in the embodiment of the present invention is higher.

[0087] It should be noted that the dyeing effect of the fabric sample can more accurately reflect the application effect of the actual process, while the subsequent slow dyeing test is based on the small sample. Although the difference in the dyed fabric surface of the small sample may not be obvious from a visual inspection, the results of small batch dyeing cannot reflect the difference in dyeing effect in large-scale production.

[0088] 3. Slow-dyeing

[0089] According to the dyeing and finishing technical regulations, dyeing operations are carried out synchronously after the dye solution is prepared. Starting from room temperature, the temperature is heated from room temperature to 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, and 98℃ at a heating rate of 3℃ / min, and kept at 98℃ for 30 minutes. Samples are taken at each stage. After the sample cloth is dried, the Datacolor600 computer color measurement and matching equipment is used, and the wavelength is set to 560nm. The K / S value of each sample cloth is measured to analyze the change of K / S value with time and temperature. If the increase in dyeing rate is small during the process of heating and dyeing time extension, it indicates that the slow dyeing performance is better.

[0090] The formula for calculating dye uptake is as follows:

[0091] Dyeing rate = [(K / S)2 / (K / S)1]*100%;

[0092] Wherein, (K / S)1 is the K / S value of the final dyed cloth, and (K / S)2 is the K / S value of the dyed cloth at each temperature stage during the heating process from 40 to 98°C.

[0093] The slow dyeing performance of Examples 1-7, Comparative Example 1, Comparative Example 2, Comparative Example 4 and Comparative Example 5 of the present invention is as follows: Figure 4-8 As shown, unless otherwise specified, the fabrics used are 30D nylon + 30D spandex knitted double-sided fabrics in Table 2.

[0094] The results show that the leveling agent of Example 1 exhibits the best slow dyeing property. In Comparative Examples 1 and 2, the average number of EO segments of fatty amine polyoxyethylene ether is increased to 20 and 30. In addition, when the molar ratio of fatty amine polyoxyethylene ether, succinic anhydride and urea is the same as that in Example 1, the urea content is too low, and the color reduction after dyeing is large (manifested as a small K / S value), which affects the dyeing quality. In Examples 2 and 3, by adjusting the ratio of fatty amine polyoxyethylene ether, succinic anhydride and urea, although the slow dyeing property is not as good as that of Example 1, it is significantly better than Comparative Example 5, and the same performance trend is shown on nylon-containing woven and knitted fabrics. In Examples 4 and 5, the average number of EO segments of castor oil polyoxyethylene ether is 20 and 60 respectively. Although its slow dyeing property is not as good as that of Example 1, it is still significantly better than Comparative Example 5. In Examples 6 and 7, the addition amount of the benzotriazole ultraviolet absorber is 2% and 6% respectively, and the slow dyeing property thereof is obviously better than the formulation without adding benzotriazole (Comparative Example 4), and is significantly better than Comparative Example 5.

[0095] The above results show that the present invention significantly improves the slow dyeing property of the leveling agent in rapid dyeing based on the reasonable combination of the components, makes the dyeing process more stable and uniform, can reduce color difference, and is more suitable for industrial dyeing process.

[0096] 4. Transmission

[0097] The dyed fabric sample (original fabric) without adding leveling agent is spliced ​​with the same amount of white fabric (transfer dye fabric) of the same material, and the leveling agent (1% owf or 1.5% owf) is added. The dyeing start temperature is 30℃, the temperature is increased at a rate of 3℃ / min, and the temperature is kept at 98℃ for 30min. After the sample fabric is washed and dried, the K / S value of the original fabric and the transfer dye fabric is measured respectively. The transfer dyeing rate (transfer dyeing rate) is calculated according to the following formula. The higher the transfer dyeing rate, the better the transfer dyeing property:

[0098] =[(K / S)2' / (K / S)1']*100%;

[0099] Wherein, (K / S)1' is the K / S value of the original fabric after transfer dyeing; (K / S)2' is the K / S value of the transfer dyed fabric after transfer dyeing.

[0100] Fig. 9 The test results of the transfer properties of Example 1, Example 4, Example 5 and Comparative Example 5 at different dosages of leveling agent are shown. The results show that Example 1 has the best transfer properties. In Example 4, the average number of EO segments of castor oil polyoxyethylene ether is 20, and although the transfer properties are not as good as those of Example 1, they are significantly better than those of Comparative Example 5; in Example 5, the average number of EO segments of castor oil polyoxyethylene ether is 60, and the transfer properties are the best.

[0101] Therefore, the overall dye migration property of the leveling agent in the embodiment is significantly improved, so that the dye can be redistributed more evenly during the dyeing process, thereby significantly improving the dyeing uniformity, enhancing the correction ability of the dyeing process, and improving the quality of the dyed product, which can better meet the industrial batch dyeing needs of nylon-containing fabrics.

[0102] In summary, the leveling agent in the embodiment has excellent slow dyeing and dye migration properties, can better meet the dyeing requirements of nylon-containing fabrics, can improve the one-time dyeing success rate, improve dyeing efficiency, reduce energy consumption, and is suitable for industrial batch application.

[0103] The embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A leveling agent, characterized in that: Including water and the following preparation materials in percentage by mass: Fatty amine polyoxyethylene ether 30%-40%; Succinic anhydride 2%-10%; Urea 0.4%-1%; Castor oil polyoxyethylene ether 5%-10%; Sodium hydroxide 1%-3%; Benzotriazole UV absorber 2%-6%; The fatty amine polyoxyethylene ether and succinic anhydride react to form an amide compound.

2. The leveling agent according to claim 1, characterized in that: The average number of EO segments in the fatty amine polyoxyethylene ether molecules is 12-18; and / or the average number of EO segments in the castor oil polyoxyethylene ether molecules is 20-60.

3. The leveling agent according to claim 1, characterized in that: The molar ratio of the fatty amine polyoxyethylene ether, succinic anhydride and urea is 1.0:0.8-1.5:0.1-0.

4.

4. The leveling agent according to claim 1, characterized in that: The benzotriazole ultraviolet absorber is selected from hydroxyphenylbenzotriazole ultraviolet absorbers; Optionally, the benzotriazole ultraviolet absorber is selected from UV-1130.

5. The leveling agent according to claim 1, characterized in that: The reaction temperature is 80-120° C., and the reaction time is 1-4 hours.

6. The leveling agent according to claim 1, characterized in that: The pH of the leveling agent is 6-8; and / or the mass percentage of water in the leveling agent is ≥50%.

7. The method for preparing a leveling agent according to any one of claims 1 to 6, characterized in that: The following steps are involved: In the presence of the urea, the fatty amine polyoxyethylene ether and succinic anhydride are reacted to form an amide compound; and the amide compound is mixed with other preparation raw materials.

8. Use of the leveling agent according to any one of claims 1 to 6 in dyeing of nylon-containing fabrics.

9. The use according to claim 8, characterized in that: The heating rate of the dyeing is 1.5-3°C / min; Optionally, the dyeing temperature rise process is a gradient temperature rise, including a first stage of temperature rise and a second stage of temperature rise, wherein the temperature range of the first stage of temperature rise is 20-60°C, the temperature range of the second stage of temperature rise is 60°C-100°C, and the first stage of temperature rise rate is greater than the second stage of temperature rise rate.

10. The use according to claim 8, characterized in that: The nylon-containing fabric includes pure nylon fabric, nylon blended fabric or nylon interwoven fabric.

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