Antifouling antibacterial thermoplastic polyurethane elastomer and preparation method thereof

Abstract

The invention discloses an antifouling and antibacterial thermoplastic polyurethane elastomer and a preparation method thereof, and belongs to the technical field of polyurethane elastomers. The elastomer is composed of polyol, diisocyanate, a composite antibacterial agent and polyethylene glycol, bio-based polyol in the polyol is prepared from castor oil through fluorination modification, anhydride reaction and sulfydryl esterification, and a fluoroalkyl side chain and an amphiphilic group introduced into a molecular structure endow a material body with antifouling performance. Stain adhesion and permeation can be inhibited without relying on a post-treatment coating; the composite antibacterial agent is formed by compounding zwitterionic quaternary ammonium salt, silver nitrate and tannic acid, and has multiple antibacterial mechanisms of electrostatic adsorption, metal ion slow release and biological membrane inhibition. The elastomer realizes excellent antifouling and antibacterial properties through the antifouling design of the bio-based polyol and the synergistic effect of the composite antibacterial agent, has the environmental protection advantage brought by the bio-based component, and is suitable for industrial production of easily polluted scenes such as medical treatment and sports equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane elastomers, and more particularly to an antifouling and antibacterial thermoplastic polyurethane elastomer and a preparation method thereof. Background Art

[0002] Thermoplastic polyurethane (TPU) is a polymer material that combines the elasticity of rubber with the processing properties of plastic. Due to its excellent wear resistance, oil resistance, low-temperature resistance, and mechanical properties, it has been widely used in medical, sports equipment, automotive, and electronic equipment fields. However, with the continuous expansion of application scenarios, higher requirements are being placed on TPU's antibacterial and antifouling properties, especially in the medical and sports equipment fields. The surface of the material is prone to bacterial growth and stains, which not only shortens its service life but also may cause cross-infection and other problems. Therefore, the development of TPU with intrinsic antifouling and antibacterial properties is of great practical significance.

[0003] At present, common antibacterial and antifouling methods mostly rely on surface coating technology, which is achieved by coating a coating with antibacterial and antifouling functions on the surface of the material. However, this type of coating has problems such as poor durability, easy wear, and easy peeling, which limits its long-term application effect. For example, patent CN117210795A discloses a method for low-temperature evaporation coating on the surface of TPU, which improves the stability of the interface between the TPU substrate and the coating by substrate surface treatment, low-temperature evaporation and optimization of coating composition technology, but its preparation process is complicated and the durability of the coating still needs to be improved. Patent CN115044088A proposes a method for preparing a flexible Cu-Ag conductive super-hydrophobic coating on the surface of TPU plastic, which realizes the preparation of super-hydrophobic coating by chemical copper plating and spraying silver-containing solution, but its preparation process involves multi-step chemical treatment, which is difficult to achieve industrial large-scale production. In the field of composite antibacterial agents, patent CN118435941A discloses a lignin-nanosilver composite antibacterial agent, which achieves antibacterial effect through the synergistic effect of lignin and nanosilver, but does not involve antifouling performance. Therefore, the present invention proposes an antifouling and antibacterial thermoplastic polyurethane elastomer and a preparation method thereof to solve the above-mentioned technical problems. Summary of the Invention

[0004] The purpose of the present invention is to provide an antifouling and antibacterial thermoplastic polyurethane elastomer and a preparation method thereof. The elastomer achieves excellent antifouling and antibacterial properties through the antifouling design of bio-based polyols and the synergistic effect of composite antibacterial agents. At the same time, it has the environmental advantages brought by bio-based ingredients and is suitable for industrial production in easily polluted scenarios such as medical and sports equipment.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An antifouling and antibacterial thermoplastic polyurethane elastomer is composed of the following raw materials in parts by weight: 35-40 parts of polyol, 15-20 parts of diphenylmethane diisocyanate, 3-8 parts of a composite antibacterial agent and 5-10 parts of polyethylene glycol.

[0007] Preferably, the polyol is composed of bio-based polyol and petroleum-based polyol in a mass ratio of 1-3:4-6.

[0008] Preferably, the preparation method of the bio-based polyol is:

[0009] A1. Castor oil, dodecafluoroheptyl acrylate, and diisobenzoyl peroxide were mixed and reacted under nitrogen at 70-75°C with stirring for 1-3 hours. After the reaction, the mixture was centrifuged and dried to obtain fluorinated castor oil. The mixture was then mixed with itaconic anhydride and reacted at 100-110°C with stirring for 4-6 hours to obtain modified castor oil.

[0010] A2. Modified castor oil and thiomalic acid were mixed, stirred and reacted at 80-85°C under nitrogen protection for 2-4 hours, and then purified by precipitation with ether and vacuum dried to obtain bio-based polyol.

[0011] Preferably, in step A1, the ingredients are 35-40 parts by weight of castor oil, 15-20 parts by weight of dodecafluoroheptyl acrylate, 1.0-1.5 parts by weight of diisobenzoyl peroxide, and 8-12 parts by weight of itaconic anhydride.

[0012] Preferably, in step A2, 30-35 parts of modified castor oil and 4-8 parts of thiomalic acid are added by weight.

[0013] Preferably, the preparation method of the composite antibacterial agent is:

[0014] S1. Mix N-methyldiethanolamine and 1,3-propane sultone, stir and react at 50-60°C under nitrogen for 1-3 hours, then add dimethyl sulfate, react at room temperature for 2-4 hours, precipitate with ethanol, and vacuum dry to obtain a zwitterionic quaternary ammonium salt;

[0015] S2. Mix silver nitrate, tannic acid and zwitterionic quaternary ammonium salt in deionized water, stir and react at 60-70° C. in the dark for 1-3 hours, centrifuge, wash with water and dry to obtain the composite antibacterial agent.

[0016] Preferably, in step S1, the components comprise, by weight, 10-15 parts of N-methyldiethanolamine, 8-12 parts of 1,3-propane sultone, and 5-10 parts of dimethyl sulfate.

[0017] Preferably, the ingredients in step S2 are 5-10 parts by weight of nitrate, 3-6 parts by weight of tannic acid, 8-14 parts by weight of zwitterionic quaternary ammonium salt, and 80-90 parts by weight of deionized water.

[0018] A method for preparing an antifouling and antibacterial thermoplastic polyurethane elastomer comprises the following steps: mixing polyol, diphenylmethane diisocyanate and polyethylene glycol, stirring and reacting at 80-90°C under nitrogen protection for 2-4 hours to form a prepolymer, adding a composite antibacterial agent, continuing to stir and react at 70-80°C for 1-2 hours to complete chain extension, and finally injecting the reaction product into a mold, hot-pressing at 100-120°C for 10-20 minutes, and demolding after cooling to obtain the finished product.

[0019] In summary, the present invention has the following beneficial effects:

[0020] 1. This invention utilizes fluorination and amphiphilic group modification of castor oil. The fluoroalkyl side chains introduced into the bio-based polyol significantly reduce the surface energy of the material, inhibiting stain adhesion. The carboxylic acid groups formed by anhydride ring opening and the amphiphilic structure introduced by thiol esterification synergistically regulate the surface hydrophilic-hydrophobic balance, forming a dynamic antifouling interface. This effectively blocks the penetration and retention of organic stains such as grease and protein without requiring a post-treatment coating, achieving the material's intrinsic antifouling function. By replacing some petroleum-based polyols with bio-based castor oil derivatives and combining them with biodegradable ester bonds introduced by thiomalic esterification, the material reduces its reliance on non-renewable resources.

[0021] 2. The composite antibacterial agent in the present invention destroys bacterial cell membranes through electrostatic adsorption of zwitterionic quaternary ammonium salts, Ag ions released slowly by silver nitrate interfere with microbial metabolism, and tannic acid inhibits biofilm formation. The three work together to construct a multi-level antibacterial network of "contact killing-ion slow release-biofilm inhibition", which has high-efficiency and broad-spectrum antibacterial activity, and the slow-release characteristics of silver ions give the material long-term antibacterial stability.

[0022] 3. The present invention adopts an integrated prepolymerization-chain extension-hot pressing process, and the composite antibacterial agent is evenly embedded in the polyurethane matrix through chemical bonding, avoiding the risk of interfacial peeling in traditional coating methods; the stable combination of the fluoroalkyl chain segment and the polyurethane hard segment microphase separation structure ensures that the material maintains stable antifouling and antibacterial properties after repeated deformation or mechanical wear. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used are purchased from conventional biochemical reagent stores unless otherwise specified. The quantitative experiments in the following examples were all repeated three times, and the data are the average or mean ± standard deviation of the three repeated experiments.

[0025] Example 1

[0026] Preparation of Bio-Based Polyols: A1. Mix 35 parts of castor oil, 15 parts of dodecafluoroheptyl acrylate, and 1 part of diisobenzoyl peroxide. Stir at 300 rpm and react at 70°C under nitrogen for 3 hours. Centrifuge and dry to obtain fluorinated castor oil. Then, add 8 parts of itaconic anhydride and stir at 100°C for 6 hours to obtain modified castor oil. A2. Combine 30 parts of modified castor oil with 4 parts of thiomalic acid, react at 80°C under nitrogen for 4 hours, precipitate with ether, and dry in vacuo to obtain bio-based polyols.

[0027] Preparation of the composite antimicrobial agent: S1. Under nitrogen protection, react 10 parts of N-methyldiethanolamine and 8 parts of 1,3-propane sultone at 50°C for 3 h with a stirring rate of 300 rpm. Subsequently, add 5 parts of dimethyl sulfate and react at room temperature for 4 h. Precipitate with ethanol to obtain a zwitterionic quaternary ammonium salt. S2. Dissolve 5 parts of silver nitrate, 3 parts of tannic acid, and 8 parts of a zwitterionic quaternary ammonium salt in 80 parts of deionized water. React at 60°C in the dark for 3 h. Wash with water and dry by centrifugation to obtain the composite antimicrobial agent.

[0028] Preparation of antifouling and antibacterial thermoplastic polyurethane elastomer: bio-based polyol and polytetramethylene ether glycol were mixed in a mass ratio of 1:4 (total polyol 35 parts), 15 parts of diphenylmethane diisocyanate and 5 parts of polyethylene glycol were added, the stirring rate was controlled at 320 rpm, and the mixture was stirred at 80°C for 4 hours to form a prepolymer; then 3 parts of a composite antibacterial agent was added, and the mixture was stirred at 70°C for 2 hours to complete the chain extension. Finally, the reaction product was injected into a mold, hot-pressed at 100°C for 20 minutes, and demolded after cooling to obtain the finished product.

[0029] Example 2

[0030] Preparation of Bio-Based Polyols: A1. Combine 38 parts of castor oil, 18 parts of dodecafluoroheptyl acrylate, and 1.3 parts of diisobenzoyl peroxide. Stir at 320 rpm and react at 72°C under nitrogen for 2.8 hours. Centrifuge and dry to obtain fluorinated castor oil. Add 10 parts of itaconic anhydride and stir at 105°C for 5.8 hours to obtain modified castor oil. A2. Combine 33 parts of modified castor oil and 6 parts of thiomalic acid. React at 83°C under nitrogen for 3.8 hours. Purify with ether precipitation and vacuum dry to obtain bio-based polyols.

[0031] Preparation of a composite antimicrobial agent: S1. Under nitrogen protection, react 12 parts of N-methyldiethanolamine and 10 parts of 1,3-propane sultone at 55°C for 2.5 hours with a stirring rate of 320 rpm. Subsequently, add 7 parts of dimethyl sulfate and react at room temperature for 3.5 hours. Precipitate with ethanol to obtain a zwitterionic quaternary ammonium salt. S2. Dissolve 7 parts of silver nitrate, 4 parts of tannic acid, and 11 parts of a zwitterionic quaternary ammonium salt in 85 parts of deionized water. React at 65°C in the dark for 2.7 hours. Wash with water and dry by centrifugation to obtain a composite antimicrobial agent.

[0032] Preparation of antifouling and antibacterial thermoplastic polyurethane elastomer: bio-based polyol and polyethylene adipate glycol were mixed in a mass ratio of 2:5 (total polyol 38 parts), 18 parts of diphenylmethane diisocyanate and 7 parts of polyethylene glycol were added, the stirring rate was controlled at 340 rpm, and the mixture was stirred at 85 ° C for 3.5 hours to form a prepolymer; then 5 parts of composite antibacterial agent were added, and the stirring reaction was continued at 75 ° C for 1.7 hours to complete the chain extension. Finally, the reaction product was injected into the mold, hot-pressed at 105 ° C for 18 minutes, and demolded after cooling to obtain the finished product.

[0033] Example 3

[0034] Preparation of bio-based polyols: A1. Mix 40 parts of castor oil, 20 parts of dodecafluoroheptyl acrylate, and 1.5 parts of diisobenzoyl peroxide. Stir at 350 rpm and react at 75°C under nitrogen for 1 hour. Centrifuge and dry to obtain fluorinated castor oil. Then add 12 parts of itaconic anhydride and stir at 110°C for 4 hours to obtain modified castor oil. A2. Combine 35 parts of modified castor oil and 8 parts of thiomalic acid. React at 85°C under nitrogen for 2 hours. Purify by precipitation with ether and vacuum dry to obtain bio-based polyols.

[0035] Preparation of the composite antimicrobial agent: S1. Under nitrogen protection, react 15 parts of N-methyldiethanolamine and 12 parts of 1,3-propane sultone at 60°C for 1 hour with a stirring rate of 350 rpm. Subsequently, add 10 parts of dimethyl sulfate and react at room temperature for 2 hours. Precipitate with ethanol to obtain a zwitterionic quaternary ammonium salt. S2. Dissolve 10 parts of silver nitrate, 6 parts of tannic acid, and 14 parts of a zwitterionic quaternary ammonium salt in 90 parts of deionized water. React at 70°C in the dark for 1 hour. Wash with water and dry by centrifugation to obtain the composite antimicrobial agent.

[0036] Preparation of antifouling and antibacterial thermoplastic polyurethane elastomer: bio-based polyol and polyethylene adipate glycol were mixed in a mass ratio of 3:6 (total polyol 40 parts), 20 parts of diphenylmethane diisocyanate and 8 parts of polyethylene glycol were added, the stirring rate was controlled at 350 rpm, and the reaction was stirred at 90 ° C for 2 hours to form a prepolymer; then 8 parts of composite antibacterial agent were added, and the stirring reaction was continued at 80 ° C for 1 hour to complete the chain extension. Finally, the reaction product was injected into the mold, hot-pressed at 120 ° C for 10 minutes, and demolded after cooling to obtain the finished product.

[0037] Example 4

[0038] Preparation of Bio-Based Polyols: A1. Combine 38 parts of castor oil, 18 parts of dodecafluoroheptyl acrylate, and 1.3 parts of diisobenzoyl peroxide. Stir at 330 rpm and react at 73°C under nitrogen for 2.5 hours. Centrifuge and dry to obtain fluorinated castor oil. Add 10 parts of itaconic anhydride and stir at 108°C for 5 hours to obtain modified castor oil. A2. Combine 33 parts of modified castor oil and 6 parts of thiomalic acid. React at 82°C under nitrogen for 3.5 hours. Purify by precipitation with ether and vacuum dry to obtain bio-based polyols.

[0039] Preparation of the composite antimicrobial agent: S1. Under nitrogen protection, react 15 parts of N-methyldiethanolamine and 10 parts of 1,3-propane sultone at 58°C for 2.5 hours with a stirring rate of 330 rpm. Subsequently, add 8 parts of dimethyl sulfate and react at room temperature for 3.5 hours. Precipitate with ethanol to obtain a zwitterionic quaternary ammonium salt. S2. Dissolve 8 parts of silver nitrate, 5 parts of tannic acid, and 12 parts of a zwitterionic quaternary ammonium salt in 90 parts of deionized water. React at 68°C in the dark for 2.5 hours. Wash with water and dry by centrifugation to obtain the composite antimicrobial agent.

[0040] Preparation of antifouling and antibacterial thermoplastic polyurethane elastomer: Bio-based polyol and polytetramethylene ether glycol were mixed in a mass ratio of 2.5:5.5 (total polyol 38 parts), 19 parts of diphenylmethane diisocyanate and 8 parts of polyethylene glycol were added, the stirring rate was controlled at 350 rpm, and the reaction was stirred at 88 ° C for 3.5 hours to form a prepolymer; then 6 parts of composite antibacterial agent were added, and the stirring reaction was continued at 78 ° C for 1.8 hours to complete the chain extension. Finally, the reaction product was injected into the mold, hot-pressed at 115 ° C for 15 minutes, and demolded after cooling to obtain the finished product.

[0041] Comparative Example 1

[0042] An antifouling and antibacterial thermoplastic polyurethane elastomer is different from Example 4 in that no bio-based polyol is used. The polyol is entirely composed of petroleum-based polyol, that is, the polyol is entirely polytetramethylene ether glycol. The remaining raw material composition and preparation method are the same as those of Example 4.

[0043] Comparative Example 2

[0044] An antifouling and antibacterial thermoplastic polyurethane elastomer is disclosed. The difference from Example 4 is that the bio-based polyol is not fluorinated. Specifically, in Step A1, the reaction between dodecafluoroheptyl acrylate and diisobenzoyl peroxide is omitted, and castor oil and itaconic anhydride are directly reacted. The remaining raw material composition and preparation method are the same as those in Example 4.

[0045] Comparative Example 3

[0046] An antifouling and antibacterial thermoplastic polyurethane elastomer is prepared. The difference from Example 4 is that the bio-based polyol is not subjected to a thiol esterification reaction. Specifically, the thiomalic acid reaction step is omitted in Step A2, and the modified castor oil obtained in Step A1 is directly used as the bio-based polyol. The remaining raw material composition and preparation method are the same as those in Example 4.

[0047] Comparative Example 4

[0048] An antifouling and antibacterial thermoplastic polyurethane elastomer is prepared. The difference from Example 4 is that no composite antibacterial agent is added, and the step of adding the composite antibacterial agent is omitted during the preparation process. The remaining raw material composition and preparation method are the same as those of Example 4.

[0049] Comparative Example 5

[0050] An antifouling and antibacterial thermoplastic polyurethane elastomer is provided. The difference from Example 4 is that the composite antibacterial agent contains only a zwitterionic quaternary ammonium salt. Specifically, silver nitrate and tannic acid are omitted in step S2, and only the zwitterionic quaternary ammonium salt obtained in step S1 is used as the antibacterial agent. The remaining raw material composition and preparation method are the same as those in Example 4.

[0051] Comparative Example 6

[0052] An antifouling and antibacterial thermoplastic polyurethane elastomer is disclosed, which differs from Example 4 in that no zwitterionic quaternary ammonium salt is used in the composite antibacterial agent. Specifically, the zwitterionic quaternary ammonium salt prepared in step S1 is omitted in step S2, and only silver nitrate and tannic acid are compounded as the antibacterial agent. The remaining raw material composition and preparation method are the same as those in Example 4.

[0053] Performance Testing

[0054] Antifouling performance: The antifouling and antibacterial thermoplastic polyurethane elastomers prepared in Examples 1-4 and Comparative Examples 1-6 were subjected to contact angle tests in accordance with GB / T 30693-2014. The static contact angles of the material surface to soybean oil and deionized water were measured using a contact angle meter. The average of three measurements was taken. The test results are shown in Table 1.

[0055] Antibacterial performance: The antifouling and antibacterial thermoplastic polyurethane elastomers prepared in Examples 1-4 and Comparative Examples 1-6 were tested for their Escherichia coli inhibition rate in accordance with ISO 22196-2011. The test results are shown in Table 1.

[0056] Mechanical properties: The tensile strength and elongation at break of the antifouling and antibacterial thermoplastic polyurethane elastomers prepared in Examples 1-4 and Comparative Examples 1-6 were tested with reference to ASTM D412. The test results are shown in Table 1.

[0057] Table 1

[0058] Test items Contact angle / °(oil / water) Antibacterial rate / % Tensile strength / MPa Elongation at break / % Example 1 128 / 115 95.1 52.5 680 Example 2 132 / 122 96.7 54.2 710 Example 3 135 / 130 98.3 56.8 730 Example 4 138 / 135 82 58.7 750 Comparative Example 1 101 / 93 94.7 53.6 560 Comparative Example 2 106 / 99 96.2 50.5 600 Comparative Example 3 115 / 103 91 51.2 655 Comparative Example 4 120 / 107 75 50.1 580 Comparative Example 5 125 / 110 91 50.4 660 Comparative Example 6 122 / 108 89 52 665

[0059] By testing and analyzing the contact angle, antibacterial rate, tensile strength and elongation at break, the present invention, through the fluorination modification and mercaptoesterification design of bio-based polyols and the synergistic effect of the composite antibacterial agent, has significantly improved the surface antifouling performance, broad-spectrum antibacterial activity and mechanical stability of the material. Compared with the comparative examples lacking key modification steps or components, the embodiments of the present invention all show obvious advantages in contact angle, antibacterial rate and mechanical properties, confirming the key influence of the synergistic effect of each technical feature on the antifouling and antibacterial performance and comprehensive material performance. Among them, the optimal embodiment achieves a good balance between antifouling and antibacterial ability and tensile and fracture performance through parameter optimization. As shown in Table 1 above, the antifouling and antibacterial thermoplastic polyurethane elastomers obtained by Examples 1-4 all show excellent comprehensive performance in terms of antifouling performance, antibacterial performance and mechanical properties. By comparison, the performance of Comparative Examples 1-6 significantly decreases.

[0060] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. An antifouling and antibacterial thermoplastic polyurethane elastomer, characterized in that: The invention is composed of the following raw materials in parts by weight: 35-40 parts of polyol, 15-20 parts of diphenylmethane diisocyanate, 3-8 parts of composite antibacterial agent and 5-10 parts of polyethylene glycol; The polyol is composed of bio-based polyol and petroleum-based polyol in a mass ratio of 1-3:4-6.

2. The antifouling and antibacterial thermoplastic polyurethane elastomer according to claim 1, characterized in that: The preparation method of the bio-based polyol is: A1. Castor oil, dodecafluoroheptyl acrylate, and diisobenzoyl peroxide were mixed and reacted under nitrogen at 70-75°C with stirring for 1-3 hours. After the reaction, the mixture was centrifuged and dried to obtain fluorinated castor oil. The mixture was then mixed with itaconic anhydride and reacted at 100-110°C with stirring for 4-6 hours to obtain modified castor oil. A2. Modified castor oil and thiomalic acid were mixed, stirred and reacted at 80-85°C under nitrogen protection for 2-4 hours, and then purified by precipitation with ether and vacuum dried to obtain bio-based polyol.

3. The antifouling and antibacterial thermoplastic polyurethane elastomer according to claim 2, characterized in that: In step A1, the components include, by weight, 35-40 parts of castor oil, 15-20 parts of dodecafluoroheptyl acrylate, 1.0-1.5 parts of diisobenzoyl peroxide, and 8-12 parts of itaconic anhydride.

4. The antifouling and antibacterial thermoplastic polyurethane elastomer according to claim 2, characterized in that: In step A2, 30-35 parts of modified castor oil and 4-8 parts of thiomalic acid are added by weight.

5. The antifouling and antibacterial thermoplastic polyurethane elastomer according to claim 1, characterized in that: The preparation method of the composite antibacterial agent is as follows: S1. Mix N-methyldiethanolamine and 1,3-propane sultone, stir and react at 50-60°C under nitrogen for 1-3 hours, then add dimethyl sulfate, react at room temperature for 2-4 hours, precipitate with ethanol, and vacuum dry to obtain a zwitterionic quaternary ammonium salt; S2. Mix silver nitrate, tannic acid and zwitterionic quaternary ammonium salt in deionized water, stir and react at 60-70° C. in the dark for 1-3 hours, centrifuge, wash with water and dry to obtain the composite antibacterial agent.

6. The antifouling and antibacterial thermoplastic polyurethane elastomer according to claim 5, characterized in that: In step S1, the components, by weight, include 10-15 parts of N-methyldiethanolamine, 8-12 parts of 1,3-propane sultone, and 5-10 parts of dimethyl sulfate.

7. The antifouling and antibacterial thermoplastic polyurethane elastomer according to claim 5, characterized in that: In step S2, the components include 5-10 parts of nitrate, 3-6 parts of tannic acid, 8-14 parts of zwitterionic quaternary ammonium salt and 80-90 parts of deionized water in parts by weight.

8. A method for preparing the antifouling and antibacterial thermoplastic polyurethane elastomer according to any one of claims 1 to 7, characterized in that: The following steps are involved: Mix polyol, diphenylmethane diisocyanate and polyethylene glycol, stir and react at 80-90°C under nitrogen protection for 2-4 hours to form a prepolymer, then add the composite antibacterial agent, continue stirring and react at 70-80°C for 1-2 hours to complete the chain extension, and finally inject the reaction product into the mold, hot press molding at 100-120°C for 10-20 minutes, and demold after cooling to obtain the finished product.