Self-healing waterborne polyurethane and preparation method and use thereof

Abstract

The application provides a self-healing waterborne polyurethane and a preparation method and use thereof. The method comprises the following steps: (1) reacting 2,6-diacetylpyridine dioxime, a polyhydric alcohol, a diisocyanate, a hydrophilic chain extender and a solvent to obtain a prepolymer of the waterborne polyurethane; (2) reacting the prepolymer of the waterborne polyurethane obtained in step (1) and a neutralizing agent to obtain a reaction solution; and emulsifying the reaction solution and a metal salt solution, and obtaining the self-healing waterborne polyurethane after solidification. The self-healing waterborne polyurethane provided by the application can overcome the shortcomings of other self-healing waterborne polyurethanes, such as high temperature conditions for self-repairing, poor healing efficiency and single function, and endows the waterborne polyurethane material with super room-temperature self-repairing performance and good antibacterial property.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane materials technology, specifically relating to a self-healing waterborne polyurethane, its preparation method, and its applications. Background Technology

[0002] Waterborne polyurethane (WPU) is a polyurethane polymer material that uses water instead of organic solvents as the dispersion medium. However, during use, it is inevitably subjected to mechanical or photothermal stimulation, resulting in various types of damage that significantly affect its performance and lifespan. In nature, organisms possess the ability to self-repair damaged tissues and functions, thereby increasing their chances of survival. Inspired by the self-repair capabilities of organisms, existing technologies have disclosed artificial self-healing materials capable of repairing damage, thereby extending the lifespan of materials and improving the reliability of various materials.

[0003] Polyurethane, with its excellent mechanical strength, good wear resistance, toughness, and low-temperature flexibility, has been widely used in many fields such as coatings, adhesives, textiles, flexible electronics, and biomaterials. In recent years, room-temperature self-healing polyurethane has received particular attention because it can repair cracks and damage and restore its original function under mild conditions, extending the material's service life and reducing maintenance costs. Furthermore, with the adoption of new repair mechanisms and strategies, the mechanical properties and room-temperature self-healing capabilities of polyurethane materials have been significantly improved in recent years.

[0004] However, the synthesis of room-temperature self-healing polyurethanes often involves complex steps and expensive functional monomers. Therefore, developing simple and low-cost methods to prepare room-temperature self-healing polyurethanes is of great significance for future industrial production. Of course, advancements in synthetic chemistry and supramolecular chemistry have provided new opportunities to address these issues. It is also important to note that current single self-healing functions are insufficient to meet the demands of high-value material development.

[0005] Therefore, there is an urgent need in this field to develop a waterborne polyurethane material to solve the technical problems that polyurethane materials cannot simultaneously possess rapid room temperature self-healing and high mechanical properties, as well as the limitation of single performance characteristics. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a self-healing waterborne polyurethane, its preparation method, and its applications. The self-healing waterborne polyurethane provided by this invention overcomes the drawbacks of other self-healing waterborne polyurethanes, such as high self-healing temperature requirements, poor healing efficiency, and limited functionality, thus endowing the waterborne polyurethane material with superior room-temperature self-healing properties and excellent antibacterial properties.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a self-healing waterborne polyurethane, the method comprising the following steps:

[0009] (1) 2,6-Diacetylpyridine dioxime, polyol, diisocyanate, hydrophilic chain extender and solvent are reacted to obtain a prepolymer of waterborne polyurethane;

[0010] (2) React the prepolymer of waterborne polyurethane obtained in step (1) with a neutralizing agent to obtain a reaction solution; emulsify the reaction solution with a metal salt solution and solidify it to obtain the self-healing waterborne polyurethane.

[0011] This invention utilizes 2,6-diacetylpyridine dioxime bonded to the polymer molecular chain of waterborne polyurethane. The 2,6-diacetylpyridine dioxime ester group contains four reversible dynamic bonds, namely two oxime ester bonds and two hydrogen bonds. The 2,6-diacetylpyridine dioxime unit acts as a ligand to coordinate with a metal to form a metal coordination bond. The cross-linked structure composed of multiple reversible dynamic bonds endows the waterborne polyurethane material with excellent room temperature self-healing properties and certain antibacterial properties, while also giving the waterborne polyurethane material good mechanical properties.

[0012] Preferably, the preparation method of 2,6-diacetylpyridine dioxime in step (1) includes the following steps: mixing 2,6-diacetylpyridine, hydroxylamine hydrochloride, sodium acetate and an organic solvent, and reacting to obtain the 2,6-diacetylpyridine dioxime.

[0013] Preferably, the organic solvent comprises a combination of ethanol and deionized water.

[0014] Preferably, the mass ratio of ethanol to deionized water is 1:(2-4), for example, it can be 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5, 1:3.8, 1:4, etc.

[0015] Preferably, the molar ratio of 2,6-diacetylpyridine, hydroxylamine hydrochloride and sodium acetate is 1:(2-4):(4-6), for example, it can be 1:2:4, 1:2.5:4.5, 1:3:5, 1:3.5:4.5, 1:4:5, 1:4:6, 1:2:6, 1:3:6, etc.

[0016] Preferably, the reaction temperature is 90-95℃, for example, 90℃, 91℃, 92℃, 93℃, 94℃, 95℃, etc.; the time is 2-3h, for example, 2h, 2.2h, 2.5h, 2.8h, 3h, etc.

[0017] Preferably, the reaction is followed by cooling, filtration, washing, and drying processes in sequence.

[0018] Preferably, the polyol in step (1) includes polyether polyol and / or polyester polyol.

[0019] Preferably, the polyether polyol includes polypropylene glycol and / or polytetrahydrofuran ether diol.

[0020] Preferably, the polyester polyol comprises polycarbonate diol and / or poly(1,4-butanediol) adipate.

[0021] Preferably, the number average molecular weight of the polyol in step (1) is 1000-2000, for example, it can be 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, etc.

[0022] In this invention, by adjusting the number-average molecular weight of the polyol, the compatibility between the soft and hard segments is improved, thereby obtaining a stable particle size distribution and good mechanical properties. If the molecular weight is too low, the rigid groups of urethane and urea will be more dense, resulting in a harder and more brittle film with poorer flexibility and increased tensile strength. Conversely, if the molecular weight is too high, the water solubility of the polyurethane molecular chain will be reduced, affecting the stability of the polyurethane emulsion, and increasing the flexibility and decreasing the strength of the material.

[0023] Preferably, the diisocyanate in step (1) is isophorone diisocyanate.

[0024] Preferably, the molar ratio of diisocyanate to polyol in step (1) is (2-3):1, for example, it can be 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, etc.

[0025] Preferably, based on the total mass of the prepolymer of the waterborne polyurethane as 100%, the mass percentage of 2,6-diacetylpyridine dioxime in step (1) is 2%-6%, for example, it can be 2%, 3%, 4%, 5%, 6%, etc.

[0026] In this invention, by adjusting the mass percentage of 2,6-diacetylpyridine dioxime, the synthesized waterborne polyurethane membrane has a certain number of dynamic bonds to maintain good healing ability while also having good mechanical properties. If the content is too low, the overall mechanical properties of the polyurethane will be poor, the tensile strain of the membrane material will be relatively high, the tensile strength will be low, and the dynamic healing effect will not be prominent. Conversely, if the content is too high, the tensile strength will be too high, the flexibility of the membrane material will decrease, and the healing ability of the material will be unfavorable.

[0027] Preferably, the hydrophilic chain extender in step (1) includes 2,2-dihydroxymethylpropionic acid.

[0028] Preferably, the solvent in step (1) includes N,N-dimethylpyrrolidone and / or acetone.

[0029] Preferably, the process of reacting 2,6-diacetylpyridine dioxime, polyol, diisocyanate, hydrophilic chain extender and solvent in step (1) is as follows: the polyol, diisocyanate, hydrophilic chain extender and solvent are reacted for the first time, and then 2,6-diacetylpyridine dioxime is added for the second reaction.

[0030] Preferably, a catalyst is added before the first reaction.

[0031] Preferably, the catalyst is stannous octoate.

[0032] Preferably, the first reaction is carried out in an inert atmosphere.

[0033] Preferably, the temperature of the first reaction is 80-85℃, for example, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, etc.; the time is 3-6h, for example, 3h, 4h, 5h, 6h, etc.

[0034] Preferably, the temperature of the second reaction is 60-65℃, for example, 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, etc.; and the time is 1.5-2h, for example, 1.5h, 1.6h, 1.7h, 1.8h, 2h, etc.

[0035] Preferably, the neutralizing agent in step (2) includes triethylamine.

[0036] Preferably, the molar ratio of the hydrophilic chain extender, solvent, and neutralizer is (0.5-1):(1-2):(0.5-1), for example, it can be 0.5:1:0.5, 0.5:1.5:1, 0.5:2:1, 0.8:1.5:0.8, 0.8:2:1, 1:1.5:1, 1:2:1, etc.

[0037] In this invention, by adjusting the molar ratio of the hydrophilic chain extender, solvent and neutralizer, the synthesized waterborne polyurethane emulsion has a more uniform particle size distribution and long-term storage capability. If the molar ratio is too low, the synthesized polyurethane emulsion will be unstable, and if it is too high, the viscosity of the synthesized polyurethane emulsion will increase, the hardness of the emulsion film will increase, and the water resistance of the film will decrease accordingly.

[0038] Preferably, the reaction temperature in step (2) is 45-50℃, for example, 45℃, 46℃, 47℃, 48℃, 49℃, 50℃, etc.; and the time is 30-40min, for example, 30min, 32min, 35min, 38min, 40min, etc.

[0039] Preferably, the stirring rate of the reaction in step (2) is 1900-2000 r / min, for example, it can be 1900 r / min, 1920 r / min, 1950 r / min, 1980 r / min, 2000 r / min, etc.

[0040] Preferably, the metal salt solution in step (2) is a copper chloride solution.

[0041] Preferably, the molar ratio of the metal salt and the 2,6-diacetylpyridine dioxime in the metal salt solution in step (2) is (0.1-1):1, more preferably (0.25-0.5):1, for example, it can be 0.1:1, 0.11:1, 0.12:1, 0.13:1, 0.14:1, 0.15:1, 0.16:1, 0.17:1, 0.18:1, 0.9:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, etc.

[0042] In this invention, by adjusting the molar ratio of metal salt and 2,6-diacetylpyridine dioxime, the modified polyurethane film can comprehensively improve its mechanical properties, self-healing ability and antibacterial ability. If the molar ratio is too low, the improvement effect on its mechanical properties and healing ability will not be obvious, and if it is too high, the mechanical properties and healing ability of the modified polyurethane material will decrease.

[0043] Preferably, the emulsification temperature in step (2) is room temperature, and the time is 30-60 minutes, for example, 30 minutes, 40 minutes, 50 minutes, 60 minutes, etc.

[0044] Preferably, the emulsification rate in step (2) is 1800-2000 r / min, for example, it can be 1800 r / min, 1850 r / min, 1900 r / min, 1920 r / min, 1950 r / min, 1980 r / min, 2000 r / min, etc.

[0045] Preferably, the curing in step (2) includes the following steps: first curing at room temperature for 24-48 hours, for example, 24 hours, 28 hours, 32 hours, 36 hours, 40 hours, 42 hours, 48 ​​hours, etc.; and then curing at 60°C for 24-32 hours, for example, 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, etc.

[0046] In a second aspect, the present invention provides a self-healing waterborne polyurethane, which is prepared by the method for preparing self-healing waterborne polyurethane according to the first aspect.

[0047] Thirdly, the present invention provides a self-healing antibacterial material, said self-healing antibacterial material comprising the self-healing aqueous polyurethane according to the second aspect.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] This invention provides a self-healing waterborne polyurethane that utilizes 2,6-diacetylpyridine dioxime bonded to the polymer molecular chain of the waterborne polyurethane. The 2,6-diacetylpyridine dioxime ester group contains four reversible dynamic bonds: two oxime ester bonds and two hydrogen bonds. The 2,6-diacetylpyridine dioxime unit acts as a ligand, coordinating with a metal to form a metal-metal coordination bond. This cross-linked structure composed of multiple reversible dynamic bonds endows the waterborne polyurethane material with superior room-temperature self-healing properties and certain antibacterial properties, while also giving the waterborne polyurethane material good mechanical properties. Attached Figure Description

[0050] Figure 1 The crack healing diagram provided for Comparative Example 1 shows the material healing at room temperature for 24 hours.

[0051] Figure 2 The image shows the crack healing process of the material provided in Example 1 after 24 hours at room temperature;

[0052] Figure 3 The image shows the crack healing process of the material provided in Example 2 after 24 hours at room temperature;

[0053] Figure 4 The stress-strain curves for Example 1(a) and Example 2(b) after healing at room temperature for different times are shown.

[0054] Figure 5 The diagram shows the inhibition zone experiments of Escherichia coli in Examples 1, 2, and 1 (Comparative Example 1). Detailed Implementation

[0055] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0056] Example 1

[0057] This embodiment provides a self-healing waterborne polyurethane and its preparation method, the preparation method comprising the following steps:

[0058] (1) 2,6-Diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate were mixed with an organic solvent (the organic solvent being composed of ethanol and deionized water in a mass ratio of 1:3), wherein the molar ratio of 2,6-diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate was 1:3:5, and the mixture was heated under reflux at 92°C for 2.5 h. Subsequently, the above reaction system was cooled to room temperature, filtered under reduced pressure, and the crude product was washed four times with a mixed solution of ethanol and deionized water (where the mass ratio of ethanol and deionized water was 1:4). Finally, the washed sample was dried at 40°C for 42 h.

[0059] Under a nitrogen atmosphere, polytetrahydrofuran ether diol (number average molecular weight of 1500) and isophorone diisocyanate in a molar ratio of 1:2.5 were stirred and heated to 82°C. The stirring speed was adjusted to 650 r / min. When the mass fraction of isocyanate functional groups in the above system no longer changed, 2,2-dihydroxymethylpropionic acid, N,N-dimethylpyrrolidone and stannous octoate catalyst were added, and 10 mL of acetone was added to adjust the viscosity. The reaction was continued for 3 h. Then, 2,6-diacetylpyridine dioxime was added, and the reaction was carried out at 62°C for 1.8 h to obtain a prepolymer of waterborne polyurethane. The mass percentage of 2,6-diacetylpyridine dioxime was 4% based on the total mass of the waterborne polyurethane prepolymer (100%).

[0060] (2) The waterborne polyurethane prepolymer obtained in step (1) and triethylamine are reacted for the first time at 48°C for 35 min to obtain a reaction solution; the reaction solution is cooled to room temperature and emulsified with copper chloride aqueous solution for 45 min at an emulsification rate of 1900 r / min. The solution is first cured at room temperature for 36 h, and then cured at 60°C for 28 h to obtain the self-healing waterborne polyurethane, wherein the molar ratio of copper chloride to 2,6-diacetylpyridine dioxime is 0.25:1, and the molar ratio of 2,2-dihydroxymethylpropionic acid, N,N-dimethylpyrrolidone and triethylamine is 1:2:1.

[0061] Example 2

[0062] This embodiment provides a self-healing waterborne polyurethane and its preparation method, the preparation method comprising the following steps:

[0063] (1) 2,6-Diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate were mixed with an organic solvent (the organic solvent being composed of ethanol and deionized water in a mass ratio of 1:2), wherein the molar ratio of 2,6-diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate was 1:3:5, and the mixture was heated under reflux at 90°C for 2.5 h. Subsequently, the above reaction system was cooled to room temperature, filtered under reduced pressure, and the crude product was washed three times with a mixed solution of ethanol and deionized water (where the mass ratio of ethanol and deionized water was 1:4). Finally, the washed sample was dried at 45°C for 48 h.

[0064] Under a nitrogen atmosphere, polytetrahydrofuran ether diol (number average molecular weight of 1000) and isophorone diisocyanate in a molar ratio of 1:2.4 were stirred, heated to 80°C, and the rotation speed was adjusted to 600 r / min. When the mass fraction of isocyanate functional groups in the above system no longer changed, 2,2-dihydroxymethylpropionic acid, N,N-dimethylpyrrolidone and stannous octoate catalyst were added, and 10 mL of acetone was added to adjust the viscosity. The reaction was continued for 3 h, and then 2,6-diacetylpyridine dioxime was added. The reaction was carried out at 60°C for 1.5 h to obtain a prepolymer of waterborne polyurethane, wherein the mass percentage of 2,6-diacetylpyridine dioxime was 3% based on the total mass of the waterborne polyurethane prepolymer as 100%.

[0065] (2) The waterborne polyurethane prepolymer obtained in step (1) and triethylamine are reacted for the first time at 50°C for 30 min to obtain a reaction solution; the reaction solution is cooled to room temperature and emulsified with copper chloride aqueous solution for 60 min at an emulsification rate of 1900 r / min. The solution is first cured at room temperature for 48 h, and then cured at 60°C for 24 h to obtain the self-healing waterborne polyurethane, wherein the molar ratio of copper chloride to 2,6-diacetylpyridine dioxime is 0.25:1, and the molar ratio of 2,2-dihydroxymethylpropionic acid, N,N-dimethylpyrrolidone and triethylamine is 1:2:1.

[0066] Example 3

[0067] This embodiment provides a self-healing waterborne polyurethane and its preparation method, the preparation method comprising the following steps:

[0068] (1) 2,6-Diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate were mixed with an organic solvent (the organic solvent being composed of ethanol and deionized water in a mass ratio of 1:2), wherein the molar ratio of 2,6-diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate was 1:3:5, and the mixture was heated under reflux at 90°C for 2.5 h. Subsequently, the above reaction system was cooled to room temperature, filtered under reduced pressure, and the crude product was washed three times with a mixed solution of ethanol and deionized water (where the mass ratio of ethanol and deionized water was 1:4). Finally, the washed sample was dried at 45°C for 48 h.

[0069] Under a nitrogen atmosphere, polytetrahydrofuran ether diol (number average molecular weight of 1000) and isophorone diisocyanate in a molar ratio of 1:2.4 were stirred, heated to 80°C, and the rotation speed was adjusted to 600 r / min. When the mass fraction of isocyanate functional groups in the above system no longer changed, 2,2-dihydroxymethylpropionic acid, N,N-dimethylpyrrolidone and stannous octoate catalyst were added, and 10 mL of acetone was added to adjust the viscosity. The reaction was continued for 3 h, and then 2,6-diacetylpyridine dioxime was added. The reaction was carried out at 60°C for 1.5 h to obtain a prepolymer of waterborne polyurethane, wherein the mass percentage of 2,6-diacetylpyridine dioxime was 3% based on the total mass of the waterborne polyurethane prepolymer as 100%.

[0070] (2) The waterborne polyurethane prepolymer obtained in step (1) and triethylamine are reacted for the first time at 50°C for 30 min to obtain a reaction solution; the reaction solution is cooled to room temperature and emulsified with copper chloride aqueous solution for 50 min at an emulsification rate of 1900 r / min. The solution is first cured at room temperature for 48 h, and then cured at 60°C for 24 h to obtain the self-healing waterborne polyurethane, wherein the molar ratio of copper chloride to 2,6-diacetylpyridine dioxime is 0.5:1, and the molar ratio of 2,2-dihydroxymethylpropionic acid, N,N-dimethylpyrrolidone and triethylamine is 1:2:1.

[0071] Example 4

[0072] This embodiment provides a self-healing waterborne polyurethane and its preparation method, the preparation method comprising the following steps:

[0073] (1) 2,6-Diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate were mixed with an organic solvent (the organic solvent being composed of ethanol and deionized water in a mass ratio of 1:2), wherein the molar ratio of 2,6-diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate was 1:2:4, and the mixture was heated under reflux at 90°C for 3 h. Subsequently, the above reaction system was cooled to room temperature, filtered under reduced pressure, and the crude product was washed three times with a mixed solution of ethanol and deionized water (where the mass ratio of ethanol and deionized water was 1:4). Finally, the washed sample was dried at 30°C for 48 h.

[0074] Under a nitrogen atmosphere, polytetrahydrofuran ether diol (number average molecular weight of 1000) and isophorone diisocyanate in a molar ratio of 1:2 were stirred, heated to 80°C, and the rotation speed was adjusted to 600 r / min. When the mass fraction of isocyanate functional groups in the above system no longer changed, 2,2-dihydroxymethylpropionic acid, N,N-dimethylpyrrolidone and stannous octoate catalyst were added, and an appropriate amount of acetone was added to adjust the viscosity. The reaction was continued for 2.5 h, and then 2,6-diacetylpyridine dioxime was added. The reaction was carried out at 60°C for 1.5 h to obtain a prepolymer of waterborne polyurethane. The mass percentage of 2,6-diacetylpyridine dioxime was 2% based on the total mass of the waterborne polyurethane prepolymer as 100%.

[0075] (2) The waterborne polyurethane prepolymer obtained in step (1) and triethylamine are reacted for the first time at 45°C for 30 min to obtain a reaction solution; the reaction solution is cooled to room temperature and emulsified with copper chloride aqueous solution for 30 min at an emulsification rate of 1800 r / min. The solution is first cured at room temperature for 24 h, and then cured at 60°C for 24 h to obtain the self-healing waterborne polyurethane, wherein the molar ratio of copper chloride to 2,6-diacetylpyridine dioxime is 0.25:1, and the molar ratio of 2,2-dihydroxymethylpropionic acid, N,N-dimethylpyrrolidone and triethylamine is 1:2:1.

[0076] Example 5

[0077] This embodiment provides a self-healing waterborne polyurethane and its preparation method, the preparation method comprising the following steps:

[0078] (1) 2,6-Diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate were mixed with an organic solvent (the organic solvent being composed of ethanol and deionized water in a mass ratio of 1:4), wherein the molar ratio of 2,6-diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate was 1:4:6, and the mixture was heated under reflux at 95°C for 3 h. Subsequently, the above reaction system was cooled to room temperature, filtered under reduced pressure, and the crude product was washed 5 times with a mixed solution of ethanol and deionized water (where the mass ratio of ethanol and deionized water was 1:4). Finally, the washed sample was dried at 45°C for 32 h.

[0079] Under a nitrogen atmosphere, polytetrahydrofuran ether diol (number average molecular weight of 2000) and isophorone diisocyanate in a molar ratio of 1:3 were stirred, heated to 85°C, and the rotation speed was adjusted to 700 r / min. When the mass fraction of isocyanate functional groups in the above system no longer changed, 2,2-dihydroxymethylpropionic acid, N,N-dimethylpyrrolidone and stannous octoate catalyst were added, and an appropriate amount of acetone was added to adjust the viscosity. The reaction was continued for 3.5 h, and then 2,6-diacetylpyridine dioxime was added. The reaction was carried out at 65°C for 1.5 h to obtain a prepolymer of waterborne polyurethane. The mass percentage of 2,6-diacetylpyridine dioxime was 6% based on the total mass of the waterborne polyurethane prepolymer as 100%.

[0080] (2) The waterborne polyurethane prepolymer obtained in step (1) and triethylamine are reacted for the first time at 50°C for 40 min to obtain a reaction solution; the reaction solution is cooled to room temperature and emulsified with copper chloride aqueous solution for 60 min at an emulsification rate of 2000 r / min. The solution is first cured at room temperature for 48 h, and then cured at 60°C for 32 h to obtain the self-healing waterborne polyurethane, wherein the molar ratio of copper chloride to 2,6-diacetylpyridine dioxime is 0.5:1, and the molar ratio of 2,2-dihydroxymethylpropionic acid, N,N-dimethylpyrrolidone and triethylamine is 1:2:1.

[0081] Example 6

[0082] The difference between this embodiment and Example 1 is that the number average molecular weight of polytetrahydrofuran ether diol in step (1) is 500, while the rest is the same as in Example 1.

[0083] Example 7

[0084] The difference between this embodiment and Example 1 is that the number average molecular weight of polytetrahydrofuran ether diol in step (1) is 2500, while the rest is the same as in Example 1.

[0085] Example 8

[0086] The difference between this embodiment and Example 1 is that, taking the total mass of the waterborne polyurethane prepolymer as 100%, the mass percentage of 2,6-diacetylpyridine dioxime in step (1) is 1%, and all other aspects are the same as in Example 1.

[0087] Example 9

[0088] The difference between this embodiment and Example 1 is that, taking the total mass of the waterborne polyurethane prepolymer as 100%, the mass percentage of 2,6-diacetylpyridine dioxime in step (1) is 10%, and all other aspects are the same as in Example 1.

[0089] Example 10

[0090] The difference between this embodiment and Example 1 is that the molar ratio of copper chloride and 2,6-diacetylpyridine dioxime in the copper chloride aqueous solution in step (2) is 0.05:1, while all other aspects are the same as in Example 1.

[0091] Example 11

[0092] The difference between this embodiment and embodiment 1 is that the molar ratio of copper chloride and 2,6-diacetylpyridine dioxime in the copper chloride aqueous solution in step (2) is 3:1, while all other aspects are the same as in embodiment 1.

[0093] Example 12

[0094] The difference between this embodiment and embodiment 1 is that the copper chloride aqueous solution in step (2) is replaced with ferric chloride solution, while all other aspects are the same as in embodiment 1.

[0095] Comparative Example 1

[0096] The difference between this comparative example and Example 1 is that the copper chloride aqueous solution in step (2) is replaced with an equal amount of deionized water, while everything else is the same as in Example 1.

[0097] Test conditions

[0098] The self-healing waterborne polyurethane provided in Examples 1 to 12 and Comparative Example 1 was tested using the following methods:

[0099] (1) Microscopic testing: Optical microscopic images of the film healing process were monitored in real time using a polarizing microscope (model POM, Axio Imager A2POL, UK) on a heated stage at a magnification of 50. The sample was scraped with a blade to about 50% of its thickness.

[0100] (2) Antibacterial Test: The antibacterial properties of the modified polyurethane film were determined by the inhibition zone test. All experimental equipment was autoclaved before the experiment. 40 μl of activated Escherichia coli (Gram-negative, ATCC 25922) was evenly spread on solid agar medium. Then, a polyurethane film with a diameter of 1 cm was made into a circle and placed on the medium. The film was then incubated in a constant temperature incubator at 37℃. After 24 h of incubation, the presence of an inhibition zone around the polyurethane film on the medium was observed.

[0101] (3) Tensile property test: The sample was cut into dumbbell (2mm×10mm) shaped strips using a mold. The test was conducted at an ambient temperature of 25℃ and a relative humidity of 65%–85%. Tensile stress and tensile strain were measured using a dual-column benchtop testing system to determine the mechanical properties of the polyurethane film. The tensile rate was 20mm / min. The test results are shown in Table 1.

[0102] Table 1

[0103]

[0104]

[0105] As can be seen from Table 1, such as Figures 1-4 As shown, the self-healing waterborne polyurethane provided in Examples 1-2 of this invention not only has excellent room temperature self-healing properties and certain antibacterial properties, but also gives the waterborne polyurethane material good mechanical properties.

[0106] Examples 6-7 show cases where the number-average molecular weight of polytetrahydrofuran ether diol exceeds the preferred range. This indicates that a lower molecular weight leads to a higher density of rigid groups in the urethane and urea groups, resulting in a harder and more brittle synthesized film with poorer flexibility and increased tensile strength. Conversely, a higher molecular weight reduces the water solubility of the polyurethane molecular chain, affecting the stability of the polyurethane emulsion and increasing the material's flexibility while decreasing its strength. Examples 8-9 show cases where the mass percentage content of 2,6-diacetylpyridine dioxime exceeds the preferred range. This indicates that a lower content results in poor overall mechanical properties of the polyurethane, a higher tensile strain ratio in the film material, lower tensile strength, and a less prominent dynamic healing effect. Conversely, a higher content results in excessively high tensile strength, decreased flexibility of the film material, and poor healing ability. Examples 10-11 show cases where the molar ratio of copper chloride to 2,6-diacetylpyridine dioxime exceeds the preferred range. This indicates that a lower molar ratio results in an insignificant improvement in mechanical properties and healing ability. Conversely, a higher molar ratio results in a decrease in the mechanical properties and healing ability of the modified polyurethane material.

[0107] Example 12 illustrates the case where copper chloride solution is replaced with ferric chloride solution. Since divalent copper ions can directly interact with the bacterial cell membrane and enter the bacterial cell, when the intracellular copper ion concentration reaches a certain level, oxidative stress occurs, leading to the breakage of intracellular proteins and DNA, and the gradual loss of the cell membrane's barrier function. Cell membrane permeability gradually increases, cell contents leak out, and the bacterial cell becomes inactive. In contrast, trivalent ferric ions are less likely to exhibit corresponding biological characteristics compared to divalent copper ions. Ferric ions are an essential nutrient for most organisms, including bacteria, and participate in life processes such as electron transport and DNA synthesis. Therefore, bacteria can rely on absorbing iron ions to meet their growth and metabolic needs. Conversely, this lack of antibacterial effect indicates a disadvantage of not being antibacterial.

[0108] like Figure 5 As shown, the material prepared in Comparative Example 1 has poor mechanical properties and no antibacterial zone appears.

[0109] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A self-healing antibacterial material, characterized in that, The self-healing antibacterial material includes self-healing waterborne polyurethane; The self-healing waterborne polyurethane is prepared by the following method, which includes the following steps: (1) 2,6-Diacetylpyridine dioxime, polyol, diisocyanate, hydrophilic chain extender and solvent are reacted to obtain a prepolymer of waterborne polyurethane; (2) React the prepolymer of waterborne polyurethane obtained in step (1) with a neutralizing agent to obtain a reaction solution; emulsify the reaction solution with a metal salt solution and solidify it to obtain the self-healing waterborne polyurethane; The number-average molecular weight of the polyol mentioned in step (1) is 1000-2000; Based on the total mass of the prepolymer of the waterborne polyurethane being 100%, the mass percentage of 2,6-diacetylpyridine dioxime in step (1) is 2%-6%; The metal salt solution mentioned in step (2) is a copper chloride solution; The molar ratio of the metal salt in the metal salt solution and the 2,6-diacetylpyridine dioxime in step (2) is (0.1-1):

1.

2. The self-healing antibacterial material according to claim 1, characterized in that, The preparation method of 2,6-diacetylpyridine dioxime in step (1) includes the following steps: mixing 2,6-diacetylpyridine, hydroxylamine hydrochloride, sodium acetate and organic solvent, and reacting to obtain the 2,6-diacetylpyridine dioxime.

3. The self-healing antibacterial material according to claim 2, characterized in that, The organic solvent includes a combination of ethanol and deionized water.

4. The self-healing antibacterial material according to claim 3, characterized in that, The mass ratio of ethanol to deionized water is 1:(2-4).

5. The self-healing antibacterial material according to claim 2, characterized in that, The molar ratio of 2,6-diacetylpyridine, hydroxylamine hydrochloride, and sodium acetate is 1:(2-4):(4-6).

6. The self-healing antibacterial material according to claim 2, characterized in that, The reaction is carried out at a temperature of 90-95℃ for 2-3 hours.

7. The self-healing antibacterial material according to claim 2, characterized in that, The reaction is followed by cooling, filtration, washing, and drying processes in sequence.

8. The self-healing antibacterial material according to claim 1, characterized in that, The polyols mentioned in step (1) include polyether polyols and / or polyester polyols.

9. The self-healing antibacterial material according to claim 8, characterized in that, The polyether polyols include polypropylene glycol and / or polytetrahydrofuran ether diol.

10. The self-healing antibacterial material according to claim 8, characterized in that, The polyester polyols include polycarbonate diols and / or poly(1,4-butanediol) adipate.

11. The self-healing antibacterial material according to claim 1, characterized in that, The diisocyanate mentioned in step (1) is isophorone diisocyanate.

12. The self-healing antibacterial material according to claim 1, characterized in that, The molar ratio of diisocyanate to polyol in step (1) is (2-3):

1.

13. The self-healing antibacterial material according to claim 1, characterized in that, The hydrophilic chain extender mentioned in step (1) includes 2,2-dihydroxymethylpropionic acid.

14. The self-healing antibacterial material according to claim 1, characterized in that, The solvents mentioned in step (1) include N,N-dimethylpyrrolidone and / or acetone.

15. The self-healing antibacterial material according to claim 1, characterized in that, The process of reacting 2,6-diacetylpyridine dioxime, polyol, diisocyanate, hydrophilic chain extender and solvent in step (1) is as follows: the polyol, diisocyanate, hydrophilic chain extender and solvent are reacted for the first time, and then 2,6-diacetylpyridine dioxime is added for the second reaction.

16. The self-healing antibacterial material according to claim 15, characterized in that, The first reaction also includes the addition of a catalyst.

17. The self-healing antibacterial material according to claim 16, characterized in that, The catalyst is stannous octoate.

18. The self-healing antibacterial material according to claim 15, characterized in that, The first reaction was carried out in an inert atmosphere.

19. The self-healing antibacterial material according to claim 15, characterized in that, The temperature of the first reaction is 80-85℃, and the time is 3-6 hours.

20. The self-healing antibacterial material according to claim 15, characterized in that, The second reaction is carried out at a temperature of 60-65℃ for 1.5-2 hours.

21. The self-healing antibacterial material according to claim 1, characterized in that, The neutralizing agent mentioned in step (2) includes triethylamine.

22. The self-healing antibacterial material according to claim 1, characterized in that, The molar ratio of the hydrophilic chain extender, solvent, and neutralizer is (0.5-1):(1-2):(0.5-1).

23. The self-healing antibacterial material according to claim 1, characterized in that, The reaction in step (2) is carried out at a temperature of 45-50℃ for 30-40 minutes.

24. The self-healing antibacterial material according to claim 1, characterized in that, The stirring rate of the reaction in step (2) is 1900-2000 r / min.

25. The self-healing antibacterial material according to claim 1, characterized in that, The molar ratio of the metal salt in the metal salt solution and the 2,6-diacetylpyridine dioxime in step (2) is (0.25-0.5):

1.

26. The self-healing antibacterial material according to claim 1, characterized in that, The emulsification temperature in step (2) is room temperature, and the time is 30-60 min.

27. The self-healing antibacterial material according to claim 1, characterized in that, The emulsification rate in step (2) is 1800-2000 r / min.

28. The self-healing antibacterial material according to claim 1, characterized in that, The curing process described in step (2) includes the following steps: first curing at room temperature for 24-48 hours, and then curing at 60°C for 24-32 hours.

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