A method for purifying aziridine crosslinking agents

Abstract

The application discloses a kind of aziridine crosslinking agent's purification method, belong to chemical industry field.Aziridine crosslinking agent's purification method includes the following steps: with adipoyl chloride and methyl aziridine as raw material, preparation aziridine crosslinking agent oil crude product material;White material is precipitated by slow cooling to the material, stirring, every time interval, add once slightly soluble solvent;Material is filtered, and the crude product is obtained, and dried at low temperature.The application uses the alternate use of slightly soluble solvent and easily soluble solvent, so that the material is precipitated to the maximum extent, solves the problem that the crystallization time is long in traditional process, and the solubility of material is not easy to observe in easily soluble solvent, the product yield is high, and the purity can be maintained.

Description

Technical Field

[0001] This invention belongs to the field of chemical engineering, and specifically relates to a method for purifying aziridine crosslinking agents. Background Technology

[0002] Aziridine crosslinking agents are crosslinking functional materials with aziridine groups at their core. They significantly improve the mechanical properties and stability of polymer materials through efficient covalent crosslinking reactions. Compared to traditional crosslinking systems, aziridine crosslinking agents have unique advantages: they do not produce small molecule byproducts during the crosslinking process, the reaction is highly controllable, and they can be directly applied in aqueous dispersions or solutions. They are widely added to adhesives, resins, and polymer dispersions as adhesive strength enhancers and reinforcing agents, and form a stable crosslinked network after drying or heat treatment. Among them, crosslinking agents represented by 1,1'-adiaziridine are increasingly widely used in the adhesive field due to their high functionality (each molecule contains multiple active groups), high reaction efficiency, and convenient operation.

[0003] However, the industrial production of this compound faces a significant bottleneck: 1,1'-adiazinodiaziridine has a low melting point, making it difficult to form stable crystals during purification and crystallization. Conventional purification processes rely on ultra-low temperature conditions to achieve solidification, but the resulting solid is prone to remelting due to temperature fluctuations during subsequent processing (such as filtration and drying), resulting in insufficient product purity and low yield. For example, in patent application number 201910296900.8, the purification of crude azinodiaziridine requires distillation at 45-95℃ for 4-10 hours, followed by collection of the fraction at 20-60℃ under reduced pressure for 8-12 hours, resulting in long crystallization time and high energy consumption. This defect not only limits its large-scale production efficiency and cost control but may also affect the performance of the final crosslinked product, such as mechanical strength and aging resistance, due to residual impurities. Therefore, developing an efficient and low-cost purification process to overcome the crystallization difficulties in existing technologies is key to promoting the further application of this type of high-performance crosslinking agent. Summary of the Invention

[0004] The purpose of this invention is to provide a purification method for aziridine-based crosslinking agents, using adipyl chloride and methylaziridine as reactants to produce an oily crude product. In the post-processing, to address the issue of difficulty in observing the solubility of the material in readily soluble solvents, a sparingly soluble solvent is first used, followed by heating and then adding the readily soluble solvent to saturate the material. The material is then cooled to allow crystallization, and the sparingly soluble solvent is added in batches to maximize precipitation while maintaining product purity. This purification process avoids the inconveniences of conventional processes involving ultra-low temperatures and prolonged precipitation during crystallization.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for purifying an aziridine-based crosslinking agent includes the following steps: S1: Add aziridine, triethylamine and solvent into the reaction flask, and inertize with nitrogen gas; S2: Under controlled temperature conditions, slowly add adipic acid chloride. After the addition is complete, raise the temperature to room temperature and monitor the reaction until it ends; cool down, filter, and obtain the filtrate. S3: Add stabilizer to filtrate, heat to dryness, add sparingly soluble solvent, filter, and heat filtrate to a certain temperature; S4: Add an easily soluble solvent to the material and stir until the material is completely dissolved; slowly cool down to a certain temperature until a white material precipitates out, stir, and add a sparingly soluble solvent every once in a while; S5: Filter the material to obtain a crude product, and dry it at a low temperature.

[0006] The solvent in S1 is at least one of benzene, dichloromethane, toluene, and tetrahydrofuran, and the amount added is 1.5-3 times the sum of the weights of adipic acid chloride, aziridine, and triethylamine.

[0007] The temperature in S2 is controlled to be -10 to -5℃.

[0008] The molar ratio of adipicoyl chloride to aziridine in S2 is 1:2.0-3.0, and the molar ratio of adipicoyl chloride to triethylamine is 1:2.0-3.0.

[0009] In step S2, the temperature is lowered to below 5°C.

[0010] The stabilizer in S3 is at least one of diethanolamine, 2-amino-2-methyl-1-propanol, polyetheramine, and tetramethylethylenediamine.

[0011] Adding stabilizers can prevent the hydrolysis and ring-opening of aziridine rings; amine stabilizers can also capture free radicals and prevent the product from oxidative degradation during heating. In addition, adding stabilizers can regulate the surface tension of the solution, promote crystal nucleation and growth, and improve the regularity of the product crystal form.

[0012] The sparingly soluble solvent in S3 is at least one of cyclohexane, n-hexane, n-heptane, and petroleum ether.

[0013] The amount of the sparingly soluble solvent added is 1-1.5 times the theoretical yield.

[0014] In step S3, the temperature is raised to no more than 65°C.

[0015] The readily soluble solvent in S4 is at least one of ethyl acetate, dichloromethane, methyl tert-butyl ether, and 1,4-dioxane.

[0016] The temperature in S4 is 5-10℃.

[0017] The interval time in S4 is 2-3 hours.

[0018] The amount of sparingly soluble solvent added in S4 is 0.3-0.8 times the amount of sparingly soluble solvent added in S3.

[0019] This invention uses adipyl chloride and methylaziridine as reactants to produce an oily crude product. Low-polarity solvents such as n-hexane and petroleum ether are added to reduce the polarity of the system, promoting the precipitation of impurities (such as unreacted acyl chlorides and triethylamine hydrochloride), which are then removed by filtration. After heating to 50-60°C, high-polarity solvents such as ethyl acetate are added to increase the solubility of the product, forming a homogeneous solution. Cooling further reduces solubility, bringing the material to saturation. Adding a sparingly soluble solvent further reduces polarity, causing staged crystallization and promoting orderly crystal growth. This effectively reduces impurity entrapment and improves the purity of aziridine-based crosslinking agents.

[0020] Therefore, the present invention has the following beneficial effects: (1) The present invention first prepares an oily crude product of aziridine crosslinking agent, and through the alternating use of sparingly soluble solvents and readily soluble solvents, the material is precipitated to the maximum extent, solving the problems of long crystallization time and difficulty in observing the solubility of the material in readily soluble solvents in traditional processes. (2) The product yield is high, with a yield of up to 94%, and the product purity is maintained at over 99%. Detailed Implementation

[0021] The present invention will be further described below through specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0022] Example 1 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55g of methylaziridine, 50.6g of triethylamine, and 300g of dichloromethane to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5℃. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5℃. Filter to obtain the filtrate; (2) Add a small amount of diethanolamine to the material, heat and evaporate to dryness, then add 60g of n-hexane; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of ethyl acetate to the material to make it clear and transparent; (5) Slowly cool down to about 10°C. Material will precipitate out. Stir for 2 hours, then add 30g of cyclohexane and continue stirring for 3 hours. Cool the material down to 5°C, add 30g of n-hexane again, and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0023] Example 2 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55 g of methylaziridine, 50.6 g of triethylamine, and 300 g of tetrahydrofuran to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6 g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5 °C. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5 °C. Filter to obtain the filtrate; (2) Add a small amount of polyetheramine to the material, heat and evaporate to dryness, then add 50g of n-heptane; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of ethyl acetate to the material to make it clear and transparent; (5) Slowly cool down to about 10°C. Material will precipitate out. Stir for 2 hours, then add 20g of n-heptane and continue stirring for 2 hours. Cool the material down to 5°C, then add 25g of n-heptane again and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0024] Example 3 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55 g of methylaziridine, 50.6 g of triethylamine, and 250 g of toluene to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6 g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5 °C. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is complete. Cool the material to below 5 °C. Filter to obtain filtrate; (2) Add a small amount of 2-amino-2-methyl-1-propanol to the material, heat and evaporate to dryness, then add 60g of petroleum ether; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of ethyl acetate to the material to make it clear and transparent; (5) Slowly cool to about 10°C. Material will precipitate out. Stir for 3 hours, then add 30g of petroleum ether and continue stirring for 3 hours. Cool the material to 5°C and add another 40g of petroleum ether. Continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0025] Example 4 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55g of methylaziridine, 50.6g of triethylamine, and 240g of benzene to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5℃. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5℃. Filter to obtain the filtrate; (2) Add a small amount of tetramethylethylenediamine to the material, heat and evaporate to dryness, then add 60g of cyclohexane; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of ethyl acetate to the material to make it clear and transparent; (5) Slowly cool the material to about 10°C. Material will precipitate out. Stir for 2 hours, then add 35g of cyclohexane and continue stirring for 3 hours. Cool the material to 5°C, add another 30g of cyclohexane, and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0026] Example 5 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55g of methylaziridine, 50.6g of triethylamine, and 280g of dichloromethane to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5℃. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5℃. Filter to obtain the filtrate; (2) Add a small amount of diethanolamine to the material, heat and evaporate to dryness, then add 60g of n-hexane; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of dichloromethane to the material to make it clear and transparent; (5) Slowly cool down to about 10°C. Material will precipitate out. Stir for 3 hours, then add 25g of n-hexane and continue stirring for 3 hours. Cool the material down to 5°C, then add 30g of n-hexane again and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0027] Example 6 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55g of methylaziridine, 50.6g of triethylamine, and 300g of dichloromethane to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5℃. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5℃. Filter to obtain the filtrate; (2) Add a small amount of diethanolamine to the material, heat and evaporate to dryness, then add 50g of n-hexane; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of methyl tert-butyl ether to the material to make the material clear and transparent; (5) Slowly cool down to about 10°C. Material will precipitate out. Stir for 2 hours, then add 35g of n-hexane and continue stirring for 3 hours. Cool the material down to 5°C, then add another 40g of n-hexane and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0028] Example 7 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55g of methylaziridine, 50.6g of triethylamine, and 300g of dichloromethane to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5℃. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5℃. Filter to obtain the filtrate; (2) Add a small amount of diethanolamine to the material, heat and evaporate to dryness, then add 60g of n-hexane; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of 1,4-dioxane to the material to make the material clear and transparent; (5) Slowly cool down to about 10°C. Material will precipitate out. Stir for 3 hours, then add 30g of n-hexane and continue stirring for 2 hours. Cool the material down to 5°C, then add another 40g of n-hexane and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0029] Example 8 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55 g of methylaziridine, 50.6 g of triethylamine, and 290 g of dichloromethane to a reaction flask and inert it twice with nitrogen. Slowly add 36.6 g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5 °C. After the addition is complete, allow it to naturally warm to room temperature until the reaction is finished. Cool the material to below 5 °C. Filter to obtain the filtrate; (2) Add a small amount of diethanolamine to the material, heat and evaporate to dryness, then add 55g of n-heptane; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of ethyl acetate to the material to make it clear and transparent; (5) Slowly cool down to about 10°C. Material will precipitate out. Stir for 2 hours, then add 40g of n-heptane and continue stirring for 3 hours. Cool the material down to 5°C, add another 20g of n-heptane, and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0030] Example 9 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55g of methylaziridine, 50.6g of triethylamine, and 295g of dichloromethane to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5℃. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5℃. Filter to obtain the filtrate; (2) Add a small amount of diethanolamine to the material, heat and evaporate to dryness, then add 50g of petroleum ether; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of ethyl acetate to the material to make it clear and transparent; (5) Slowly cool down to about 10°C. Material will precipitate out. Stir for 3 hours, then add 30g of petroleum ether and continue stirring for 2 hours. Cool the material down to 5°C, add another 30g of petroleum ether, and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0031] Example 10 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55 g of methylaziridine, 50.6 g of triethylamine, and 270 g of dichloromethane to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6 g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5 °C. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5 °C. Filter to obtain the filtrate; (2) Add a small amount of diethanolamine to the material, heat and evaporate to dryness, then add 55g of cyclohexane; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of ethyl acetate to the material to make it clear and transparent; (5) Slowly cool the material to about 10°C. Material will precipitate out. Stir for 2 hours, then add 20g of cyclohexane and continue stirring for 2 hours. Cool the material to 5°C, then add 35g of cyclohexane again and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0032] Comparative Example 1 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55g of methylaziridine, 50.6g of triethylamine, and 300g of dichloromethane to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5℃. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5℃. Filter to obtain the filtrate; (2) Cool to -20℃ to induce crystallization; (3) Filter to obtain a white filter cake.

[0033] The difference between this comparative example and Example 1 is that a traditional purification method was used, in which the prepared crude crosslinking agent was directly cooled to -20°C to crystallize, without the use of stabilizers and alternating solvents.

[0034] Comparative Example 2 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55g of methylaziridine, 50.6g of triethylamine, and 300g of dichloromethane to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5℃. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5℃. Filter to obtain the filtrate; (2) Add a small amount of diethanolamine to the material, heat and evaporate to dryness, then add 120g of n-hexane; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of ethyl acetate to the material to make it clear and transparent; (5) Filter the material at low temperature to obtain a white filter cake.

[0035] The difference between this comparative example and Example 1 is that all the n-hexane was added at once, instead of adding n-hexane at regular intervals.

[0036] Comparative Example 3 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55g of methylaziridine, 50.6g of triethylamine, and 300g of dichloromethane to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5℃. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5℃. Filter to obtain the filtrate; (2) Add a small amount of diethanolamine to the material, heat and evaporate to dryness, then add 60g of n-hexane; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of ethyl acetate to the material to make it clear and transparent; (5) Slowly cool down to about 5°C. Some material will precipitate out. After stirring for 2 hours, add 30g of cyclohexane and continue stirring for 3 hours. Then add 30g of n-hexane again and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0037] The difference between this comparative example and Example 1 is that in step (5), the temperature was lowered to 5°C all at once, without segmented cooling.

[0038] Comparative Example 4 A method for preparing an aziridine-based crosslinking agent includes the following steps: (1) Preparation of crude methylaziridine: a. Add 28.55g of methylaziridine, 50.6g of triethylamine, and 300g of dichloromethane to a reaction flask, and inertize twice with nitrogen. Slowly add 36.6g of adipic acid chloride dropwise to the above system. The material releases a large amount of heat, so control the temperature between -10 and -5℃. After the addition is complete, allow the temperature to rise naturally to room temperature until the reaction is finished. Cool the material to below 5℃. Filter to obtain the filtrate; (2) To Add a small amount of diethanolamine to the material, heat and evaporate to dryness, then add 60g of diethyl ether; (3) Filter the material, heat the filtrate to 60°C, stir, and the material will become turbid; (4) Slowly add a small amount of acetone to the material to make it clear and transparent; (5) Slowly cool down to about 10°C. Material will precipitate out. Stir for 2 hours, then add 25g of cyclohexane and continue stirring for 3 hours. Cool the material down to 5°C, then add 30g of n-hexane again and continue stirring for 1 hour. (6) The material is filtered at low temperature to obtain a white filter cake.

[0039] The difference between this comparative example and Example 1 is that the sparingly soluble solvent used is diethyl ether, and the readily soluble solvent is acetone. All other conditions are the same as in Example 1.

[0040] The materials obtained in each embodiment and comparative example were placed at a temperature below 30°C and dried under high vacuum to obtain a white powder. The powder was weighed and its yield was calculated. Its purity was determined by gas chromatography, and the results are shown in Table 1.

[0041] Table 1 shows the yield, production rate, and purity of each example and comparative example.

[0042] As shown in Table 1, in terms of yield and efficiency, the crosslinking agent yields in Examples 1-10 were all higher than those in Comparative Examples 1-4, reaching over 40g, and the yields were over 90%, reaching a maximum of 94%, indicating higher yields. Compared to Example 1, Comparative Example 1 used a traditional purification method, directly cooling the prepared crude crosslinking agent to -20℃ for crystallization, resulting in a yield of 73%, far lower than that of Example 1. Furthermore, due to the low melting point of aziridine crosslinking agents, they easily remelted during ultra-low temperature crystallization, making the process difficult and the crystallization time longer. In Comparative Examples 2-4, the yields of crosslinking agents obtained by adding all n-hexane at once, cooling to 5℃ at once, and using other readily soluble and sparingly soluble solvents, respectively, were all around 70%, lower than the yields of the examples, indicating poor purification effects. In terms of purity, the purity of Examples 1-10 all reached 99%, with a maximum of 99.99%, while the purity of Comparative Examples 1-4 was around 90%. Therefore, the purification method of the aziridine crosslinking agent of the present invention can maximize the precipitation of materials, and the prepared aziridine crosslinking agent has a high yield and extremely high product purity, avoiding the process inconvenience caused by ultra-low temperature and long precipitation time in conventional processes.

[0043] This invention provides a purification method for aziridine crosslinking agents. First, impurities are removed with a low-polarity solvent. After heating, an easily soluble solvent is introduced to dissolve the product. Then, orderly crystal precipitation is achieved by gradient cooling and batch addition of a poorly soluble solvent. In conjunction with an amine stabilizer, the ring-opening side reaction of aziridine is suppressed. Finally, a high-purity (≥99%) and high-yield (92-94%) 1,1'-adiaziridine crosslinking agent is obtained. This method solves the problems of high energy consumption, low efficiency, and easy remelting of the product caused by the reliance on ultra-low temperature crystallization in traditional processes.

Claims

1. A method for purifying an aziridine-based crosslinking agent, characterized in that, Includes the following steps: S1: Add aziridine, triethylamine and solvent into the reaction flask, and inertize with nitrogen gas; S2: Under controlled temperature conditions, slowly add adipic acid chloride. After the addition is complete, raise the temperature to room temperature and monitor the reaction until it ends; cool down, filter, and obtain the filtrate. S3: Add stabilizer to filtrate, heat and evaporate to dryness, then add sparingly soluble solvent, filter, and heat filtrate; S4: Add an easily soluble solvent to the material and stir until the material is completely dissolved; slowly cool until a white material precipitates out, stir, and add a sparingly soluble solvent every once in a while; S5: Filter the material to obtain a crude product, and dry it at a low temperature.

2. The purification method for aziridine-based crosslinking agents according to claim 1, characterized in that, The solvent in S1 is at least one of benzene, dichloromethane, toluene, and tetrahydrofuran, and the amount added is 1.5-3 times the sum of the weights of adipic acid chloride, aziridine, and triethylamine.

3. The purification method for aziridine-based crosslinking agents according to claim 1, characterized in that, In S2, the temperature is controlled at -10 to -5°C, the molar ratio of adipic acid chloride to aziridine is 1:(2.0-3.0), and the molar ratio of adipic acid chloride to triethylamine is 1:(2.0-3.0).

4. The purification method for aziridine crosslinking agents according to claim 1 or 3, characterized in that, The temperature in S2 is reduced to below 5°C.

5. The purification method for aziridine-based crosslinking agents according to claim 1, characterized in that, The stabilizer in S3 is at least one of diethanolamine, 2-amino-2-methyl-1-propanol, polyetheramine, and tetramethylethylenediamine.

6. The purification method for aziridine-based crosslinking agents according to claim 1, characterized in that, The sparingly soluble solvent in S3 is at least one of cyclohexane, n-hexane, n-heptane, and petroleum ether, and the temperature is raised to no more than 65°C.

7. The purification method for aziridine-based crosslinking agents according to claim 1, characterized in that, The readily soluble solvent in S4 is at least one of ethyl acetate, dichloromethane, methyl tert-butyl ether, and 1,4-dioxane.

8. The purification method for aziridine-based crosslinking agents according to claim 1, characterized in that, The temperature in S4 is 5-10℃.

9. The purification method for aziridine-based crosslinking agents according to claim 1, characterized in that, The interval time in S4 is 2-3 hours.

10. The purification method for the aziridine crosslinking agent according to claim 1 or 7, characterized in that, The amount of sparingly soluble solvent added in S4 is 0.3-0.8 times the amount of sparingly soluble solvent added in S3.

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