Anionic waterborne polyurethane resin as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of high-molecular polymers, and particularly relates to anionic waterborne polyurethane resin as well as a preparation method and application thereof. The invention relates to a high-temperature-resistant polyester polyol, which comprises the following components: 70-85 parts by mass of macromolecular polyol; 20 to 30 parts by mass of polyisocyanate; 4-12 parts by mass of a hydrophilic chain extender; 1-5 parts by mass of a small molecular alcohol chain extender; 1-6 parts by mass of a small molecular alcohol end-capping reagent; 2-10 parts by mass of an amine chain extender; 0.01 to 0.5 part by mass of a catalyst; 3-9 parts by mass of a salt-forming agent; wherein the small molecular alcohol end-capping reagent is hydroxyethyl piperidine carboxylic acid isobutyl ester. According to the invention, hydroxyethyl isobutyl piperidinecarboxylate is adopted as a micromolecular alcohol end-capping reagent, the prepared waterborne polyurethane has mosquito and insect repelling effects after being dried, and the mosquito and insect repelling effects can be more stable and lasting by end capping of hydroxyethyl isobutyl piperidinecarboxylate.

Description

Technical Field

[0001] The invention belongs to the technical field of high molecular polymers, and in particular relates to an anionic waterborne polyurethane resin and a preparation method and application thereof. Background Art

[0002] At present, synthetic leather products are becoming more and more common, and have largely replaced natural leather, which is in short supply, to make boxes, bags, shoes, car interiors and furniture decorations, etc. Waterborne polyurethane is also widely used due to its safety and environmental protection characteristics.

[0003] Traditional methods of repelling mosquitoes include using mosquito nets, burning mosquito coils, spraying mosquito repellent liquids, etc. The use of products such as mosquito coils and mosquito repellent liquids is not suitable for some people with respiratory diseases due to their strong odors. In addition, the duration of mosquito coils and mosquito repellent liquids is limited. As the mosquito coils are extinguished or the mosquito repellent liquid dissipates, the mosquito repellent effect is weakened. In addition, existing water-based polyurethanes do not have the function of repelling mosquitoes and insects. Therefore, an anionic water-based polyurethane resin and its preparation method and application are urgently needed to solve the above problems. Summary of the invention

[0004] In order to overcome the defects in the prior art, the present invention provides an anionic waterborne polyurethane resin and a preparation method and application thereof. The present invention has the advantage of long mosquito and insect repellent time.

[0005] To achieve one of the above purposes, the present invention adopts the following technical solution:

[0006] An anionic waterborne polyurethane resin comprises the following components:

[0007] 70-85 parts by weight of macromolecular polyol;

[0008] 20 to 30 parts by weight of polyisocyanate;

[0009] 4 to 12 parts by weight of a hydrophilic chain extender;

[0010] 1 to 5 parts by weight of small molecule alcohol chain extender;

[0011] 1 to 6 parts by weight of small molecule alcohol capping agent;

[0012] 2 to 10 parts by weight of amine chain extender;

[0013] Catalyst 0.01-0.5 parts by mass;

[0014] 3 to 9 parts by weight of salt-forming agent;

[0015] Among them, the small molecule alcohol capping agent is hydroxyethylpiperidinecarboxylic acid isobutyl ester.

[0016] Preferably, the macromolecular polyol is one or a combination of two or more of polyester polyol, polyether polyol, polycarbonate polyol, polytetramethylene ether polyol, polyethylene oxide polyol, polypropylene oxide polyol, polyester ether polyol, polysiloxane polyol and bio-based polyol; the molecular weight of the macromolecular polyol is 1000-3000.

[0017] Preferably, the polyisocyanate is toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, methylcycloethyl diisocyanate, hexamethylene diisocyanate, dicycloethylmethane diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate, tetramethyl meta-xylylene diisocyanate, norbornane diisocyanate, dimethyl biphenyl diisocyanate, methylcycloethyl diisocyanate and dimethyl diphenylmethane diisocyanate, or a combination of two or more thereof.

[0018] Preferably, the hydrophilic chain extender is one or both of dimethylol propionic acid and dimethylol butyric acid.

[0019] Preferably, the small molecule alcohol chain extender is one or a combination of two or more of ethylene glycol, 1,4-butanediol, 1,2-propylene glycol, neopentyl glycol, methyl propylene glycol, 1,6-hexanediol, 1,3-propylene glycol, butyl ethyl propylene glycol, diethyl pentanediol, trimethyl pentanediol, ethyl hexanediol, dodecanediol and cyclohexanediol.

[0020] Preferably, the amine chain extender is one or a combination of two or more of isophorone diamine, diaminocyclohexylmethane, ethylenediamine, trimethylethylenediamine and hexamethylenediamine.

[0021] Preferably, the catalyst is one or a combination of two or more of an organic bismuth catalyst, an organic tin catalyst and a tertiary amine catalyst; and the salt-forming agent is one or a combination of two or more of triethylamine, ammonia water and sodium hydroxide.

[0022] To achieve the second objective, the present invention provides a method for preparing an anionic waterborne polyurethane resin, comprising the following steps:

[0023] Weigh the raw materials in parts by mass, first react the macromolecular polyol and polyisocyanate at 85-95° C. for 1.5-2 hours; then add a hydrophilic chain extender, a small molecule alcohol chain extender and a catalyst to react at 70-85° C. for 4-5 hours; then add a small molecule alcohol end-capping agent to react at 70-85° C. for 1-2 hours, finally cool to 10-20° C., add a salt-forming agent to neutralize; add low-temperature deionized water for emulsification, then drop an amine chain extender, and perform reduced pressure distillation after the reaction to obtain a waterborne polyurethane resin.

[0024] Preferably, acetone is added at the same time as the hydrophilic chain extender to dissolve the hydrophilic chain extender and reduce viscosity, and the amount of acetone added is 2w% to 3w% of the total amount of raw materials added; before adding the salt-forming agent, acetone is added in an amount of 10w% to 30w% of the total amount of raw materials added; to avoid the high viscosity of the reaction mixture leading to difficulty in emulsification, the amount of acetone can be increased as appropriate according to the viscosity of the system, and the added acetone will be removed after the reaction is completed.

[0025] To achieve the third of the above objectives, the present invention provides an application of an anionic waterborne polyurethane resin, wherein the waterborne polyurethane resin is used to prepare durable leather that repels mosquitoes and insects.

[0026] The advantages of the present invention are:

[0027] (1) The present invention provides a self-repellent mosquito and insect repellent water-based polyurethane resin, wherein hydroxyethyl piperidine carboxylic acid isobutyl ester is reacted onto a polyurethane segment through a chemical reaction to form a polymer, so that hydroxyethyl piperidine carboxylic acid isobutyl ester is converted from a monomer into a part of the polymer, and can be slowly released, thereby greatly improving the durability of mosquito and insect repellent. Different mosquito repellent effects can be achieved according to different added amounts, and a long-lasting mosquito and insect repellent effect can be achieved without adding an external mosquito repellent. The resin can be used to make mosquito repellent leather or mosquito repellent rubber products, etc., and has a wide range of applications.

[0028] (2) The waterborne polyurethane resin of the present invention uses hydroxyethyl piperidine carboxylic acid isobutyl ester as a capping agent. The chemical name of hydroxyethyl piperidine carboxylic acid isobutyl ester is 1-(1-sec-butyl carboxylate)-2-(2-hydroxyethyl) piperidine. It can repel insects safely, effectively and environmentally friendly without directly killing insects. Its principle is to effectively repel insects without harming the health of users through the volatilization of odor, so that users are free from the pain of mosquito bites, and can replace DEET, which has a bad odor and high viscosity.

[0029] (3) The present invention reacts hydroxyethyl piperidine carboxylic acid isobutyl ester to the polyurethane linker through a chemical reaction, which allows it to be slowly released, and compared with the back-end addition, the durability is greatly improved. Hydroxyethyl piperidine carboxylic acid isobutyl ester is easily soluble in organic solvents and has a primary hydroxyl group, which can react with polyisocyanates. The emulsion synthesis process is simple and efficient, and can be widely used in the leather manufacturing field.

[0030] (4) The low-temperature deionized water added in the present invention can reduce the occurrence of side reactions and improve the quality of the prepared waterborne polyurethane resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the structural formula of hydroxyethylpiperidinecarboxylic acid isobutyl ester of the present invention.

[0032] Figure 2 This is a structural formula in which isobutyl hydroxyethylpiperidinylcarboxylate is used as a capping agent to access the main chain. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] 80g of polytetrahydrofuran ether polyol (molecular weight 3000) was dehydrated at 105°C for 1h, then cooled to 50°C, 27g of toluene diisocyanate was added, and the temperature was raised to 85°C for 2 hours. The NCO content was measured after 2 hours. When the theoretical value was reached, the temperature was lowered to 50°C, and then 10g of DMPA (dihydroxymethyl propionic acid), 2g of 1,4-butanediol, 0.4g of organic bismuth catalyst and 20g of acetone were added and reacted at 80°C for 4 hours. h, then add 2g of hydroxyethylpiperidinecarboxylic acid isobutyl ester and react at 70°C for 2h. After the reaction, measure the NCO content, then cool to 20°C, add 40g of acetone to reduce viscosity and 7.3g of triethylamine to neutralize. After 5min, add low-temperature deionized water under high-speed shear. After the prepolymer is opened, slowly add 3g of ethylenediamine dropwise. After reacting for 5min, distill under reduced pressure to remove acetone in the system to obtain waterborne polyurethane resin sample 1 with a solid content of 35%.

[0036] The waterborne polyurethane resin sample 1 was made into a leather sample, and the leather sample was tested with reference to GB / T 30126-2013 "Testing and Evaluation of Mosquito-Repellent Properties of Textiles". The test results showed that the repellency rate reached 93.11%. The leather sample was placed in a 50°C oven for one month and then tested again, and the repellency rate reached 82.67%.

[0037] The emulsion was spread and solidified to obtain a waterborne polyurethane film. The tensile strength and elongation at break of the obtained waterborne polyurethane film were tested according to GB / T 1040-92 "Test Method for Tensile Properties of Plastics". The test results showed that the tensile strength was 12.8 MPa and the elongation at break was 660.2%. The waterborne polyurethane resin was applied to the formulation for preparing leather to obtain leather with excellent mosquito repellent performance.

[0038] Example 2

[0039] 78g of poly (neopentyl adipate glycol) polyol (molecular weight 2000) was dehydrated at 105°C for 1h, then cooled to 50°C, 24g of isophorone diisocyanate was added, the temperature was raised to 90°C and kept for 2 hours, the NCO content was measured after 2 hours, and when the theoretical value was reached, the temperature was lowered to 50°C, and then 6g of DMPA (dihydroxymethyl propionic acid), 2g of methyl propanediol, 0.4g of an organic bismuth catalyst and 20g of acetone were added and reacted at 70°C for 5h , then add 1.5g of hydroxyethylpiperidinecarboxylic acid isobutyl ester and react at 70℃ for 2h. After the reaction, measure the NCO content, then cool to 20℃, add 40g of acetone to reduce viscosity and 7.3g of triethylamine to neutralize. After 5min, add low-temperature deionized water under high-speed shear. After the prepolymer is opened, slowly add 3g of trimethylethylenediamine. After reacting for 5min, distill under reduced pressure to remove acetone in the system to obtain waterborne polyurethane resin sample 2 with a solid content of 34%.

[0040] The waterborne polyurethane resin sample 2 was made into a leather sample, and the leather sample was tested with reference to GB / T 30126-2013 "Testing and Evaluation of Mosquito Repellent Properties of Textiles". The test results showed that the repellency rate reached 86.67%. The leather sample was placed in a 50°C oven for one month and then tested again, and the repellency rate reached 77.47%.

[0041] The emulsion was spread and solidified to obtain a waterborne polyurethane film. The tensile strength and elongation at break of the obtained waterborne polyurethane film were tested according to GB / T 1040-92 "Test Method for Tensile Properties of Plastics". The test results showed that the tensile strength was 23.4 MPa and the elongation at break was 512.2%. The waterborne polyurethane resin was applied to the formulation for preparing leather to obtain leather with excellent mosquito repellent performance.

[0042] Example 3

[0043] 75g of polypropylene glycol polyol (molecular weight 2000) was dehydrated at 105°C for 1h, then cooled to 50°C, 25g of 1,6-hexamethylene diisocyanate (hexamethylene diisocyanate) was added, and the temperature was raised to 90°C for 2 hours. The NCO content was measured after 2 hours. When the theoretical value was reached, the temperature was lowered to 50°C, and then 6g of DMPA (dihydroxymethylbutyric acid), 4g of 1,4-butanediol, 0.4g of an organic tin catalyst and 20g of acetone were added at 7 The mixture was reacted at 5°C for 4h, and then 3g of isobutyl hydroxyethylpiperidinecarboxylate was added and reacted at 70°C for 2h. After the reaction, the NCO content was determined, and then the temperature was lowered to 20°C, 40g of acetone was added to reduce the viscosity and 7.3g of triethylamine was added to neutralize. After 5min, low-temperature deionized water was added under high-speed shear. After the prepolymer was opened, 3g of hexamethylenediamine was slowly added dropwise. After reacting for 5min, the acetone in the system was removed by vacuum distillation to obtain a waterborne polyurethane resin sample 3 with a solid content of 34%.

[0044] The waterborne polyurethane resin sample 3 was made into a leather sample, and the leather sample was tested with reference to GB / T 30126-2013 "Testing and Evaluation of Mosquito-Repellent Properties of Textiles". The test results showed that the repellency rate reached 96.67%. The leather sample was placed in a 50°C oven for one month and then tested again, and the repellency rate reached 86.67%.

[0045] The emulsion was spread and solidified to obtain a waterborne polyurethane film. The tensile strength and elongation at break of the obtained waterborne polyurethane film were tested according to GB / T 1040-92 "Test Method for Tensile Properties of Plastics". The test results showed that the tensile strength was 8.4 MPa and the elongation at break was 960.2%. The waterborne polyurethane resin was applied to the formulation for preparing leather to obtain leather with excellent mosquito repellent performance.

[0046] Example 4

[0047] 40g of polytetrahydrofuran ether polyol (molecular weight 1000) and 40g of polyethylene glycol polyol (molecular weight 1000) were dehydrated at 95°C for 30 minutes, then cooled to 50°C, 30g of toluene diisocyanate was added, the temperature was raised to 85°C for 2 hours, the NCO content was measured after 2 hours, and the temperature was lowered to 50°C when the theoretical value was reached, and then 2g of 1,4-butanediol, 0.4g of organic tin catalyst and 20g of acetone were added to react at 80°C for 4h, and then 2g of hydroxyethyl piperidine carboxylic acid isobutyl ester was added to react at 70°C for 2h, the NCO content was measured after the reaction was completed, 40g of acetone was added to reduce the viscosity, and then the temperature was lowered to 10°C, and low-temperature deionized water was added under high-speed shearing. After the prepolymer was opened, 3g of ethylenediamine was slowly added dropwise, and after reacting for 5min, the acetone in the system was removed by reduced pressure distillation to obtain waterborne polyurethane resin sample 4 with a solid content of 35.2%.

[0048] The waterborne polyurethane resin sample 4 was made into a leather sample, and the leather sample was tested with reference to GB / T 30126-2013 "Testing and Evaluation of Mosquito Repellent Properties of Textiles". The test results showed that the repellency rate reached 91.33%. The leather sample was placed in a 50°C oven for one month and then tested again, and the repellency rate reached 81.00%.

[0049] The emulsion was spread and solidified to obtain a waterborne polyurethane film. The tensile strength and elongation at break of the obtained waterborne polyurethane film were tested according to GB / T 1040-92 "Test Method for Tensile Properties of Plastics". The test results showed that the tensile strength was 10.2 MPa and the elongation at break was 530.2%. The waterborne polyurethane resin was applied to the formulation for preparing leather to obtain leather with excellent mosquito repellent performance.

[0050] Example 5

[0051] 40g of poly(neopentyl adipate) polyol (molecular weight 2000) and 38g of polyethylene glycol polyol (molecular weight 1000) were dehydrated at 95°C for 30min, then cooled to 50°C, 24g of isophorone diisocyanate was added, the temperature was raised to 90°C and kept for reaction for 2 hours, the NCO content was measured after 2 hours, and when the theoretical value was reached, the temperature was lowered to 50°C, and then 6g of DMPA (dihydroxymethyl propionic acid), 0.6g of methyl propanediol, 0.4g of The tertiary amine catalyst and 20g of acetone were reacted at 85°C for 4h, and then 1.5g of isobutyl hydroxyethylpiperidinecarboxylate was added and reacted at 70°C for 2h. After the reaction, the NCO content was measured, 40g of acetone was added to reduce the viscosity, and then the temperature was lowered to 10°C, and low-temperature deionized water was added under high-speed shear. After the prepolymer was opened, 3g of ethylenediamine was slowly added dropwise. After reacting for 5min, the acetone in the system was removed by reduced pressure distillation to obtain a waterborne polyurethane resin sample 5 with a solid content of 34.5%.

[0052] The waterborne polyurethane resin sample 5 was made into a leather sample, and the leather sample was tested with reference to GB / T 30126-2013 "Testing and Evaluation of Mosquito-Repellent Properties of Textiles". The test results showed that the repellency rate reached 85.67%. The leather sample was placed in a 50°C oven for one month and then tested again, and the repellency rate reached 77.67%.

[0053] The emulsion was spread and solidified to obtain a waterborne polyurethane film. The tensile strength and elongation at break of the obtained waterborne polyurethane film were tested according to GB / T 1040-92 "Test Method for Tensile Properties of Plastics". The test results showed that the tensile strength was 16.5 MPa and the elongation at break was 722.2%. The waterborne polyurethane resin was applied to the formulation for preparing leather to obtain leather with excellent mosquito repellent performance.

[0054] Comparative Example 1

[0055] 80g of polytetrahydrofuran ether polyol (molecular weight 3000) was dehydrated at 105°C for 1h, then cooled to 50°C, 27g of toluene diisocyanate was added, the temperature was raised to 85°C and kept for reaction for 2 hours, the NCO content was measured after 2 hours, and the temperature was lowered to 50°C when the theoretical value was reached, and then 10g of DMPA (dihydroxymethyl propionic acid), 3.2g of 1,4-butanediol, 0.4g of organic bismuth catalyst and 20g of acetone were added to react at 80°C for 4h, the NCO content was measured after the reaction was completed, and then the temperature was lowered to 20°C, 40g of acetone was added to reduce viscosity and 7.3g of triethylamine was neutralized, after 5min, deionized water was added under high-speed shear, dispersed for 1min, 3g of ethylenediamine was slowly added dropwise, reacted for 5min, and vacuum distilled to remove acetone in the system to obtain waterborne polyurethane resin sample 6 with a solid content of 34.5%.

[0056] The waterborne polyurethane resin sample 6 was made into a leather sample, and the leather sample was tested with reference to GB / T 30126-2013 "Testing and Evaluation of Mosquito Repellent Properties of Textiles". The test results showed that the repellency rate reached 7.73%. The leather sample was placed in a 50°C oven for one month and then tested again, and the repellency rate reached 6.33%.

[0057] The emulsion was spread and solidified to obtain a waterborne polyurethane film. The tensile strength test and elongation at break test were performed on the obtained waterborne polyurethane film according to GB / T 1040-92 "Test Method for Tensile Properties of Plastics". The test results were: the tensile strength was 20.1 MPa, and the elongation at break was 820.3%.

[0058] Comparative Example 2

[0059] 1.5 g of isobutyl hydroxyethylpiperidinylcarboxylate was added to the waterborne polyurethane resin sample 6, and the mixture was stirred evenly to obtain a waterborne polyurethane sample 7.

[0060] The waterborne polyurethane resin sample 7 was made into a leather sample, and the leather sample was tested with reference to GB / T 30126-2013 "Testing and Evaluation of Mosquito Repellent Properties of Textiles". The test results showed that the repellency rate reached 93.7%. The leather sample was placed in a 50°C oven for one month and then tested again, and the repellency rate reached 6.33%. It can be seen that the mosquito repellent effect has decreased significantly.

[0061] The emulsion was spread and solidified to obtain a waterborne polyurethane film. The tensile strength test and elongation at break test were performed on the obtained waterborne polyurethane film according to GB / T 1040-92 "Test Method for Tensile Properties of Plastics". The test results were: the tensile strength was 19.8 MPa and the elongation at break was 833.2%.

[0062] Through the above comparison, it can be seen that after the waterborne polyurethane resin prepared in Examples 1-5 is prepared into leather, the mosquito repellent durability is significantly higher than the mosquito repellent duration after the waterborne polyurethane resin in Comparative Examples 1-2 is prepared into leather.

[0063] The determination of NCO content in the above examples and comparative examples is used to determine the degree of reaction. Figure 1 is the structural formula of hydroxyethylpiperidinecarboxylic acid isobutyl ester of the present invention; Figure 2 This is the structural formula of Example 1-5, in which isobutyl hydroxyethylpiperidinecarboxylate is used as a capping agent to be connected to the main chain.

[0064] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An anionic waterborne polyurethane resin, characterized in that: Includes the following components: 70-85 parts by weight of macromolecular polyol; 20 to 30 parts by weight of polyisocyanate; 4 to 12 parts by weight of a hydrophilic chain extender; 1 to 5 parts by weight of small molecule alcohol chain extender; 1 to 6 parts by weight of small molecule alcohol capping agent; 2 to 10 parts by weight of amine chain extender; Catalyst 0.01-0.5 parts by mass; 3 to 9 parts by weight of salt-forming agent; Wherein, the small molecule alcohol capping agent is hydroxyethylpiperidinecarboxylic acid isobutyl ester.

2. An anionic waterborne polyurethane resin according to claim 1, characterized in that: The macromolecular polyol is one or a combination of two or more of polyester polyol, polyether polyol, polycarbonate polyol, polytetramethylene ether polyol, polyethylene oxide polyol, polypropylene oxide polyol, polyester ether polyol, polysiloxane polyol and bio-based polyol.

3. An anionic waterborne polyurethane resin according to claim 1, characterized in that: The polyisocyanate is one or a combination of two or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, methylcycloethyl diisocyanate, hexamethylene diisocyanate, dicycloethylmethane diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate, tetramethyl meta-xylylene diisocyanate, norbornane diisocyanate, dimethyl biphenyl diisocyanate, methylcycloethyl diisocyanate and dimethyl diphenylmethane diisocyanate.

4. An anionic waterborne polyurethane resin according to claim 1, characterized in that: The hydrophilic chain extender is one or both of dimethylol propionic acid and dimethylol butyric acid.

5. An anionic waterborne polyurethane resin according to claim 1, characterized in that: The small molecule alcohol chain extender is one or a combination of two or more of ethylene glycol, 1,4-butanediol, 1,2-propylene glycol, neopentyl glycol, methyl propylene glycol, 1,6-hexanediol, 1,3-propylene glycol, butyl ethyl propylene glycol, diethyl pentanediol, trimethyl pentanediol, ethyl hexanediol, dodecanediol and cyclohexanediol.

6. An anionic waterborne polyurethane resin according to claim 1, characterized in that: The amine chain extender is one or a combination of two or more of isophorone diamine, diaminocyclohexylmethane, ethylenediamine, trimethylethylenediamine and hexamethylenediamine.

7. An anionic waterborne polyurethane resin according to claim 1, characterized in that: The catalyst is one or a combination of two or more of an organic bismuth catalyst, an organic tin catalyst and a tertiary amine catalyst; the salt-forming agent is one or a combination of two or more of triethylamine, ammonia water and sodium hydroxide.

8. A method for preparing anionic waterborne polyurethane resin according to any one of claims 1 to 7, characterized in that: The following steps are involved: Weigh the raw materials in parts by mass, first react the macromolecular polyol and the polyisocyanate at 85-95° C. for 1.5-2 hours; then add the hydrophilic chain extender, the small molecule alcohol chain extender and the catalyst to react at 70-85° C. for 4-5 hours; then add the small molecule alcohol end-capping agent to react at 70-85° C. for 1-2 hours, finally cool to 10-20° C., add the salt-forming agent to neutralize; add deionized water for emulsification, then drop the amine chain extender, and perform vacuum distillation after the reaction to obtain a waterborne polyurethane resin.

9. The method for preparing an anionic waterborne polyurethane resin according to claim 8, characterized in that: Acetone is added while adding the hydrophilic chain extender, and the amount of acetone added is 2w% to 3w% of the total amount of raw materials added; acetone is added before adding the salt-forming agent, and the amount of acetone added is 10w% to 30w% of the total amount of raw materials added.

10. Use of the anionic waterborne polyurethane resin according to any one of claims 1 to 7, characterized in that: The waterborne polyurethane resin is used for preparing durable leather capable of repelling mosquitoes and insects.

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