Waterborne polyurethane, wool knitted fabric anti-pilling agent and preparation method and application of wool knitted fabric anti-pilling agent

Abstract

The invention discloses waterborne polyurethane, a wool knitted fabric anti-pilling agent as well as a preparation method and application of the wool knitted fabric anti-pilling agent, and belongs to the technical field of textile finishing. The waterborne polyurethane is prepared from the following raw materials: a prepolymer and a chain extender, the prepolymer is prepared from the following raw materials: polyethylene glycol, an anion regulator with-COOH groups and isophorone diisocyanate, and the molar ratio of the-OH groups in the polyethylene glycol to the-COOH groups in the anion regulator is (10-60): 1; the molar weight of the chain extender is 20%-60% of the molar weight of the residual-NCO groups in the prepolymer. The waterborne polyurethane can be used for preparing the anti-pilling agent for the wool knitted fabric, and has a good effect on improving the anti-pilling performance and durability of the wool knitted fabric.

Description

Technical Field

[0001] The invention belongs to the technical field of textile finishing and relates to a water-based polyurethane, an anti-pilling agent for wool knitted fabrics and a preparation method and application thereof. Background Art

[0002] Wool knitted fabrics offer excellent elasticity, softness, close-fitting properties, breathability, warmth retention, and comfort. However, during wear and washing, the surface of the fabric is prone to pilling due to friction, which reduces its aesthetics and comfort. Furthermore, these pilling surfaces easily attract dust and dirt, affecting both the fabric's appearance and wearability. Therefore, anti-pilling finishing is crucial for wool knitted fabrics.

[0003] At present, the commonly used methods for preventing wool knitted fabrics from pilling include the following three approaches: the first is the physical method, which uses low-temperature plasma, ultraviolet irradiation, etc. to etch the scale layer and reduce the directional friction coefficient to achieve the anti-pilling effect. However, this method has unstable anti-pilling effect and is prone to damage the elasticity of wool knitted fabrics, seriously affecting the feel; the second is the chemical method, which uses sol-gel, polyester compounds, etc. to form a thin film on the surface of wool fibers to achieve the anti-pilling effect, but the durability is average; the third is the biological method, which uses biological enzymes to destroy the scale layer and reduce the elasticity of the fabric to achieve the anti-pilling effect, but this method is also prone to damage the elasticity of wool knitted fabrics, seriously affecting the feel.

[0004] Therefore, it is necessary to provide an anti-pilling agent for wool knitted fabrics which can improve the anti-pilling performance and durability of wool knitted fabrics and has little effect on the hand feel. Summary of the Invention

[0005] In order to improve the anti-pilling performance and durability of wool knitted fabrics, the present invention aims to provide a water-based polyurethane, an anti-pilling agent for wool knitted fabrics, and a preparation method and application thereof.

[0006] The first aspect of the present invention provides a waterborne polyurethane, wherein the raw materials for preparing the waterborne polyurethane include a prepolymer and a chain extender; the raw materials for preparing the prepolymer include polyethylene glycol, an anion regulator having a -COOH group, and isophorone diisocyanate, wherein the molar ratio of the -OH groups in the polyethylene glycol to the -COOH groups in the anion regulator is (10-60):1; and the molar amount of the chain extender is 20% to 60% of the molar amount of the remaining -NCO groups in the prepolymer.

[0007] In some embodiments of the present invention, the water-based polyurethane is used for anti-pilling finishing of wool knitted fabrics.

[0008] In some embodiments of the present invention, the molar amount of the -NCO group in the isophorone diisocyanate is 1.6 to 2.4 times the molar amount of the -OH group.

[0009] In some embodiments of the present invention, the anionic modifier is dimethylolpropionic acid.

[0010] In some embodiments of the present invention, the average molecular weight of the polyethylene glycol is 400-1500.

[0011] In some embodiments of the present invention, the polyethylene glycol is PEG400, PEG600, PEG1000, or PEG1500.

[0012] In some embodiments of the present invention, the chain extender is glycerol.

[0013] The second aspect of the present invention provides a method for preparing the above-mentioned waterborne polyurethane, the preparation method comprising the following steps:

[0014] S1. After mixing polyethylene glycol with an anionic modifier, removing water and small molecules, adding isocyanate under nitrogen protection, and reacting to obtain a prepolymer;

[0015] S2. Add a mixed solution of a chain extender and an organic solvent dropwise to the prepolymer for chain extension. After the addition is completed, the reaction obtains an aqueous polyurethane.

[0016] In some embodiments of the present invention, in step S1 of the above preparation method, the removal of water and small molecules is carried out under vacuum conditions at 110-130°C.

[0017] In some embodiments of the present invention, in step S1 of the above preparation method, the reaction temperature is 60-80° C. and the reaction time is 1-4 h.

[0018] In some embodiments of the present invention, in step S2 of the above preparation method, the dropwise addition is completed within 1-3 hours, and the reaction is continued at 30-50° C. for 1-3 hours.

[0019] In a third aspect of the present invention, there is provided a use of the above-mentioned water-based polyurethane in the preparation of an anti-pilling agent for wool knitted fabrics, wherein the anti-pilling agent for wool knitted fabrics is used for performing anti-pilling finishing on wool knitted fabrics.

[0020] In some embodiments of the present invention, the application is: adding the aqueous polyurethane into water for self-emulsification to obtain an anti-pilling agent for wool knitted fabrics.

[0021] In some embodiments of the present invention, the application is: adding the waterborne polyurethane into water for self-emulsification and then adding K6[P2W 18O 62 ] to obtain an anti-pilling agent for wool knitted fabrics.

[0022] The fourth aspect of the present invention provides an anti-pilling agent for wool knitted fabrics, wherein the raw materials for preparing the anti-pilling agent for wool knitted fabrics include the following components in parts by mass: 1000 parts of the above-mentioned water-based polyurethane, 3000 parts of water, K6[P2W 18 O 62 ]0~12 servings.

[0023] In some embodiments of the present invention, the raw materials for preparing the anti-pilling agent for wool knitted fabrics include the following components in parts by mass: 1000 parts of the above-mentioned water-based polyurethane, 3000 parts of water, K6[P2W 18 O 62 ]4 to 12 servings.

[0024] A fifth aspect of the present invention provides a method for preparing an anti-pilling agent for wool knitted fabrics, comprising the following steps:

[0025] Adding the above water-based polyurethane into water for self-emulsification to obtain a water-based polyurethane emulsion;

[0026] Add K6[P2W 18 O 62 ] to obtain the anti-pilling agent for wool knitted fabrics.

[0027] In some embodiments of the present invention, in the preparation method of the above-mentioned anti-pilling agent for wool knitted fabrics, K6[P2W 18 O 62 ] and the water-based polyurethane in a mass ratio of (0-12):1000.

[0028] A sixth aspect of the present invention provides a method for anti-pilling finishing of wool knitted fabrics, the method comprising the following steps:

[0029] 1) dissolving the wool knitted fabric anti-pilling agent in water to obtain a finishing solution;

[0030] 2) immersing the wool knitted fabric in the finishing liquid for treatment;

[0031] 3) taking out the wool knitted fabric obtained by the treatment in step 2) and drying it.

[0032] In some embodiments of the present invention, the immersion temperature is 30-50° C. and the immersion time is 20-40 min.

[0033] In some embodiments of the present invention, the drying temperature is 80-100°C.

[0034] In some embodiments of the present invention, the amount of the anti-pilling agent for wool knitted fabric is 10% (owf). The bath ratio of the impregnation is preferably (10-30):1.

[0035] Compared with the prior art, the present invention has the following technical effects:

[0036] (1) The present invention adds an anionic modifier to a polyethylene glycol system to form a prepolymer with a polyethylene glycol system (with a relatively large molecular weight) as a soft segment, and then chain-extends to obtain a waterborne polyurethane. When finishing wool knitted fabrics, the waterborne polyurethane forms a thin film on the surface of the wool knitted fabric, thereby achieving the effect of improving the anti-pilling performance of the wool knitted fabric. At the same time, the anionic groups are evenly distributed on the fabric surface and the distribution amount is effectively controlled. The anionic groups in the waterborne polyurethane form ionic bonds with the amino cations in the wool to form cross-linked bonds, thereby improving the durability of the anti-pilling effect. A large number of application experiments and performance tests have proven that the waterborne polyurethane is effective in improving the anti-pilling performance and durability of wool knitted fabrics.

[0037] (2) Experiments have shown that K6[P2W 18 O 62 The addition of ] has a catalytic effect on the formation of ionic bonds and cross-linking between the anions in the water-based polyurethane and the amino cations in the wool, thereby achieving better anti-pilling effect and further improving its durability. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art may make various changes or modifications to the present invention, and equivalent changes or modifications also fall within the scope defined by the claims of the present application.

[0039] In an embodiment of the first aspect of the present invention, a waterborne polyurethane is provided, wherein the raw materials for preparing the prepolymer include a prepolymer and a chain extender; the raw materials for preparing the prepolymer include polyethylene glycol, an anionic regulator having a -COOH group, and isophorone diisocyanate, wherein the molar ratio of the -OH groups in the polyethylene glycol to the -COOH groups in the anionic regulator is (10-60):1; and the molar amount of the chain extender is 20% to 60% of the molar amount of the remaining -NCO groups in the prepolymer.

[0040] In some embodiments of the present invention, the aforementioned waterborne polyurethane is used for anti-pilling finishing of wool knitted fabrics, forming a thin film on the surface of the wool knitted fabric, thereby improving the anti-pilling performance of the wool knitted fabric. This also achieves a uniform distribution of anionic groups on the fabric surface and effective control of their distribution. The anionic groups in the waterborne polyurethane form ionic cross-linking bonds with the amino cations in the wool, thereby improving the durability of the anti-pilling effect.

[0041] In some embodiments of the present invention, the molar amount of the -NCO group in the isophorone diisocyanate is 1.6 to 2.4 times the molar amount of the -OH group.

[0042] In some embodiments of the present invention, the anion regulator is dimethylol propionic acid, and the chain extender is glycerol.

[0043] In some embodiments of the present invention, the average molecular weight of the polyethylene glycol is 400 to 1500, preferably PEG400, PEG600, PEG1000 or PEG1500.

[0044] In an embodiment of the second aspect of the present invention, a method for preparing the above-mentioned waterborne polyurethane is provided, the preparation method comprising the following steps:

[0045] S1. After mixing polyethylene glycol and anionic regulator, remove water and small molecules, add isocyanate under nitrogen protection, and react to obtain a prepolymer.

[0046] S2. Add a mixed solution of a chain extender and an organic solvent dropwise to the prepolymer for chain extension. After the addition is completed, the reaction obtains an aqueous polyurethane.

[0047] In some embodiments of the present invention, in step S1 of the above preparation method, the removal of water and small molecules is carried out under vacuum conditions at 110-130°C.

[0048] In some embodiments of the present invention, step S1 specifically comprises placing polyethylene glycol and an anionic modifier in a three-necked flask, applying vacuum at 110-130°C for 1-3 hours to remove water and small molecules, then cooling to room temperature and filling the flask with nitrogen for protection. Isocyanate is added at 60-80°C and reacted for 1-4 hours to obtain a prepolymer.

[0049] In some embodiments of the present invention, in step S2 of the above preparation method, the dropwise addition is completed within 1-3 hours, and the reaction is continued at 30-50° C. for 1-3 hours.

[0050] In an embodiment of the third aspect of the present invention, there is provided a use of the above-mentioned water-based polyurethane in preparing an anti-pilling agent for wool knitted fabrics, wherein the anti-pilling agent for wool knitted fabrics is used for performing anti-pilling finishing on wool knitted fabrics.

[0051] In some embodiments of the present invention, the application is: adding the aqueous polyurethane into water for self-emulsification to obtain an anti-pilling agent for wool knitted fabrics.

[0052] In some embodiments of the present invention, the application is: adding the waterborne polyurethane into water for self-emulsification and then adding K6[P2W 18 O 62 ], and obtain the anti-pilling agent for wool knitted fabrics. Experiments show that K6[P2W 18 O 62 The addition of ] has a catalytic effect on the formation of ionic bonds and cross-linking between the anions in the water-based polyurethane and the amino cations in the wool, thereby achieving better anti-pilling effect and further improving its durability.

[0053] In an embodiment of the fourth aspect of the present invention, an anti-pilling agent for wool knitted fabrics is provided. The raw materials for preparing the anti-pilling agent for wool knitted fabrics include the following components in parts by mass: 1000 parts of the above-mentioned water-based polyurethane, 3000 parts of water, K6[P2W 18 O 62 ]0~12 servings.

[0054] In some preferred embodiments of the present invention, the raw materials for preparing the anti-pilling agent for wool knitted fabrics include the following components in parts by mass: 1000 parts of the above-mentioned water-based polyurethane, 3000 parts of water, K6[P2W 18 O 62 ]4 to 12 servings.

[0055] In an embodiment of the fifth aspect of the present invention, a method for preparing an anti-pilling agent for wool knitted fabric is provided, comprising the following steps:

[0056] Adding the above water-based polyurethane into water for self-emulsification to obtain a water-based polyurethane emulsion;

[0057] Add K6[P2W 18 O 62 ] to obtain the anti-pilling agent for wool knitted fabrics.

[0058] In some embodiments of the present invention, in the preparation method of the above-mentioned anti-pilling agent for wool knitted fabrics, K6[P2W 18 O 62 ] and the mass ratio of the aqueous polyurethane is (0-12):1000. Preferably, K6[P2W18 O 62 ] and the water-based polyurethane in a mass ratio of (4-12):1000.

[0059] In an embodiment of the sixth aspect of the present invention, a method for anti-pilling finishing of wool knitted fabric is provided, the method comprising the following steps:

[0060] 1) dissolving the wool knitted fabric anti-pilling agent in water to obtain a finishing solution;

[0061] 2) Immersing the wool knitted fabric in the finishing liquid for treatment; preferably, the immersion temperature is 30-50° C. and the time is 20-40 minutes.

[0062] 3) taking out the wool knitted fabric obtained in step 2) and drying it. Preferably, the drying temperature is 80-100°C.

[0063] In some embodiments of the present invention, the amount of the anti-pilling agent for wool knitted fabric is 10% (owf). The bath ratio of the impregnation is preferably (10-30):1.

[0064] Specific embodiments are as follows:

[0065] Example 1

[0066] Step 1: Place 30 g of PEG400 and 1 g of dimethylolpropionic acid in a three-necked flask, evacuate at 110°C for 3 h to remove water and small molecules, then cool to room temperature and fill the three-necked flask with nitrogen for protection.

[0067] Step 2: Add 32.99 g of isophorone diisocyanate to the system in step 1 at 60° C. and react for 4 hours to obtain a prepolymer.

[0068] Step 3: 1.5 g of the prepolymer was reacted with an excess of di-n-butylamine in a toluene solution to generate the corresponding substituted urea. After the reaction was completed, the remaining di-n-butylamine was titrated with a standard HCl solution, and the mass percentage of -NCO in the prepolymer was measured to be 8.57%.

[0069] Step 4: At 30°C, add a mixed solution of 3.52g glycerol and 12g acetone to the prepolymer prepared in step 2 for chain extension. The addition should be completed within 3 hours.

[0070] Step 5: After the dropwise addition is completed, the reaction is continued at 30° C. for 3 hours to prepare a water-based polyurethane with a certain molecular weight.

[0071] Step 6: Add 198 g of deionized water to the waterborne polyurethane prepared in step 5 for self-emulsification to prepare an anti-pilling agent for wool knitted fabrics.

[0072] Example 2

[0073] Step 1: Place 50 g of PEG1000 and 0.8 g of dimethylolpropionic acid in a three-necked flask, evacuate at 120°C for 2 h to remove water and small molecules, then cool to room temperature and fill the three-necked flask with nitrogen for protection.

[0074] Step 2: Add 24.88 g of isophorone diisocyanate to the system in step 1 at 70° C. and react for 2 h to obtain a prepolymer.

[0075] Step 3: 1.5 g of the prepolymer was reacted with an excess of di-n-butylamine in a toluene solution to generate the corresponding substituted urea. After the reaction was completed, the remaining di-n-butylamine was titrated with a standard HCl solution, and the mass percentage of -NCO in the prepolymer was measured to be 6.16%.

[0076] Step 4: At 40°C, a mixed solution of 3.34g glycerol and 10g acetone was added dropwise to the prepolymer prepared in step 2 for chain extension. The addition was completed within 2 hours.

[0077] Step 5: After the dropwise addition is completed, the reaction is continued at 40° C. for 2 hours to prepare a water-based polyurethane with a certain molecular weight.

[0078] Step 6: Add 232.6 g of deionized water to the waterborne polyurethane prepared in step 5 for self-emulsification to prepare an anti-pilling agent for wool knitted fabrics.

[0079] Example 3

[0080] Step 1: Place 80 g of PEG1500 and 0.6 g of dimethylolpropionic acid in a three-necked flask, evacuate at 130°C for 1 hour to remove water and small molecules, then cool to room temperature and fill the three-necked flask with nitrogen for protection.

[0081] Step 2: Add 28.27 g of isophorone diisocyanate to the system in step 1 at 80° C. and react for 1 hour to obtain a prepolymer.

[0082] Step 3: 1.5 g of the prepolymer was reacted with an excess of di-n-butylamine in a toluene solution to generate the corresponding substituted urea. After the reaction was completed, the remaining di-n-butylamine was titrated with a standard HCl solution, and the mass percentage of -NCO in the prepolymer was measured to be 5.29%.

[0083] Step 4: At 50°C, add a mixed solution of 4.98g glycerol and 15g acetone to the prepolymer prepared in step 2 for chain extension. The addition should be completed within 1 hour.

[0084] Step 5: After the dropwise addition is completed, the reaction is continued at 50° C. for 1 hour to prepare a water-based polyurethane with a certain molecular weight.

[0085] Step 6: Add 337.1 g of deionized water to the waterborne polyurethane prepared in step 5 for self-emulsification to prepare an anti-pilling agent for wool knitted fabrics.

[0086] Example 4

[0087] Step 1: Place 50 g of PEG1000 and 0.8 g of dimethylolpropionic acid in a three-necked flask, evacuate at 120°C for 2 h to remove water and small molecules, then cool to room temperature and fill the three-necked flask with nitrogen for protection.

[0088] Step 2: Add 24.88 g of isophorone diisocyanate to the system in step 1 at 70° C. and react for 2 h to obtain a prepolymer.

[0089] Step 3: 1.5 g of the prepolymer was reacted with an excess of di-n-butylamine in a toluene solution to generate the corresponding substituted urea. After the reaction was completed, the remaining di-n-butylamine was titrated with a standard HCl solution, and the mass percentage of -NCO in the prepolymer was measured to be 6.22%.

[0090] Step 4: At 40°C, a mixed solution of 3.37g glycerol and 10g acetone was added dropwise to the prepolymer prepared in step 2 for chain extension. The addition was completed within 2 hours.

[0091] Step 5: After the dropwise addition is completed, the reaction is continued at 40° C. for 2 hours to prepare a water-based polyurethane with a certain molecular weight.

[0092] Step 6: Add 232.7 g of deionized water to the waterborne polyurethane prepared in step 5 for self-emulsification.

[0093] Step 7: At room temperature, 0.35 g K6[P2W 18 O 62 ] is added to the system of step 6, and stirred at a uniform speed to prepare an anti-pilling agent for wool knitted fabrics.

[0094] Example 5

[0095] Step 1: Place 50 g of PEG1000 and 0.8 g of dimethylolpropionic acid in a three-necked flask, evacuate at 120°C for 2 h to remove water and small molecules, then cool to room temperature and fill the three-necked flask with nitrogen for protection.

[0096] Step 2: Add 24.88 g of isophorone diisocyanate to the system in step 1 at 70° C. and react for 2 h to obtain a prepolymer.

[0097] Step 3: 1.5 g of the prepolymer was reacted with an excess of di-n-butylamine in a toluene solution to generate the corresponding substituted urea. After the reaction was completed, the remaining di-n-butylamine was titrated with a standard HCl solution, and the mass percentage of -NCO in the prepolymer was measured to be 6.13%.

[0098] Step 4: At 40°C, add a mixed solution of 3.32g glycerol and 10g acetone to the prepolymer prepared in step 2 for chain extension. The addition should be completed within 2 hours.

[0099] Step 5: After the dropwise addition is completed, the reaction is continued at 40° C. for 2 hours to prepare a water-based polyurethane with a certain molecular weight.

[0100] Step 6: Add 232.5 g of deionized water to the waterborne polyurethane prepared in step 5 for self-emulsification.

[0101] Step 7: At room temperature, 0.35 g of Na7[H4PW 18 O 62 ] is added to the system of step 6, and stirred at a uniform speed to prepare an anti-pilling agent for wool knitted fabrics.

[0102] Example 6

[0103] Step 1: Place 50 g of PEG1000 and 0.8 g of dimethylolpropionic acid in a three-necked flask, evacuate at 120°C for 2 h to remove water and small molecules, then cool to room temperature and fill the three-necked flask with nitrogen for protection.

[0104] Step 2: Add 24.88 g of isophorone diisocyanate to the system in step 1 at 70° C. and react for 2 h to obtain a prepolymer.

[0105] Step 3: 1.5 g of the prepolymer was reacted with an excess of di-n-butylamine in a toluene solution to generate the corresponding substituted urea. After the reaction was completed, the remaining di-n-butylamine was titrated with a standard HCl solution, and the mass percentage of -NCO in the prepolymer was measured to be 6.19%.

[0106] Step 4: At 40°C, a mixed solution of 3.36g glycerol and 10g acetone was added dropwise to the prepolymer prepared in step 2 for chain extension. The addition was completed within 2 hours.

[0107] Step 5: After the dropwise addition is completed, the reaction is continued at 40° C. for 2 hours to prepare a water-based polyurethane with a certain molecular weight.

[0108] Step 6: Add 232.6 g of deionized water to the waterborne polyurethane prepared in step 5 for self-emulsification.

[0109] Step 7: At room temperature, 0.35 g K5[MnV 11 O32 ] is added to the system of step 6, and stirred at a uniform speed to prepare an anti-pilling agent for wool knitted fabrics.

[0110] The anti-pilling agent prepared in Examples 1-6 was used to perform anti-pilling finishing on wool knitted fabrics. The amount of the finishing agent was 10% (owf), the bath ratio was 20:1, and the fabrics were immersed at 40°C for 30 minutes. After that, the immersed wool knitted fabric samples were dehydrated and dried (80-100°C).

[0111] Pilling ratings were tested on both original and finished wool knitted fabric samples according to GB / T 4802.3-1997, "Textile Fabrics: Pilling Test - Pilling Box Method." The finished fabrics were subjectively rated by touch using a five-person rating system. Hand feel was categorized into five levels, with 1 being the worst and 5 being the best. The wool knitted fabrics were laundered according to AATCC 135-2012, "Dimensional Stability of Fabrics After Home Laundering." After 15 washes, the fabrics were tested and rated for pilling and hand feel, assessing the durability of the fabric finishing effect.

[0112] Table 1 Performance test of anti-pilling agent on wool knitted fabric finishing effect

[0113]

[0114] As shown in Table 1, the anti-pilling agents prepared in Examples 1-6 can improve the anti-pilling performance and durability of wool knitted fabrics and have little effect on the hand feel; while the polyacid K6[P2W 18 O 62 ] can make wool knitted fabrics have better anti-pilling performance and durability.

[0115] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined in the claims and their equivalents.

Claims

1. A waterborne polyurethane, characterized in that The raw materials for preparing the waterborne polyurethane include prepolymer and chain extender; The raw materials for preparing the prepolymer include polyethylene glycol, an anion regulator having a -COOH group, and isophorone diisocyanate, wherein the molar ratio of the -OH group in the polyethylene glycol to the -COOH group in the anion regulator is (10-60):1; The molar amount of the chain extender is 20% to 60% of the molar amount of the remaining -NCO groups in the prepolymer.

2. The waterborne polyurethane according to claim 1, wherein The molar amount of the -NCO group in the isophorone diisocyanate is 1.6 to 2.4 times the molar amount of the -OH group.

3. The waterborne polyurethane according to claim 1, wherein The anion regulator is dimethylolpropionic acid.

4. The waterborne polyurethane according to claim 3, wherein The average molecular weight of the polyethylene glycol is 400-1500.

5. The waterborne polyurethane according to claim 1, characterized in that The chain extender is glycerol.

6. A method for preparing the waterborne polyurethane according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: S1. After mixing polyethylene glycol with an anionic modifier, removing water and small molecules, adding isocyanate under nitrogen protection, and reacting to obtain a prepolymer; S2. Add a mixed solution of a chain extender and an organic solvent dropwise to the prepolymer for chain extension. After the addition is completed, the reaction obtains an aqueous polyurethane.

7. The preparation method according to claim 6, characterized in that In step S1, the reaction temperature is 60-80°C and the reaction time is 1-4 hours.

8. The preparation method according to claim 6, characterized in that In step S2, the dropwise addition is completed within 1-3 hours, and the reaction is continued at 30-50°C for 1-3 hours.

9. Use of the aqueous polyurethane according to any one of claims 1 to 5 in the preparation of an anti-pilling agent for wool knitted fabrics.

10. An anti-pilling agent for wool knitted fabrics, characterized in that: The anti-pilling agent for wool knitted fabrics is obtained by adding water to the aqueous polyurethane according to any one of claims 1 to 5 and self-emulsifying the polyurethane.

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