Photo-thermal antibacterial, self-enhanced and self-healing vegetable oil-based waterborne polyurethane as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of waterborne polyurethane, and discloses photo-thermal antibacterial, self-enhanced and self-healing vegetable oil-based waterborne polyurethane. The high-temperature-resistant polyurethane elastomer is prepared from a system consisting of the following raw materials in parts by weight: 80 to 120 parts of castor oil, 60 to 80 parts of dicyclohexylmethane diisocyanate, 20 to 40 parts of hexamethylene diisocyanate, 20 to 40 parts of N-methyldiethanolamine, 20 to 50 parts of protocatechuic acid, 2 to 10 parts of metal ions, 2000 to 3000 parts of water and 0.5 to 1 part of a catalyst. Metal ions in the photo-thermal antibacterial, self-enhanced and self-healing plant oil-based waterborne polyurethane and phenolic hydroxyl groups in protocatechuic acid are coordinated and self-assembled to form metal nanoclusters, and the waterborne polyurethane material has self-enhanced and self-healing properties due to a low-bond-energy coordination aggregation state structure; meanwhile, the waterborne polyurethane film is endowed with photo-thermal antibacterial performance by the metal nanoclusters. The invention further discloses a preparation method and application of the photo-thermal antibacterial, self-enhanced and self-healing plant oil-based waterborne polyurethane.

Description

Technical Field

[0001] The present invention belongs to the technical field of waterborne polyurethane, and particularly relates to a photothermal antibacterial, self-reinforcing, self-healing vegetable oil-based waterborne polyurethane, and a preparation method and application thereof. Background Art

[0002] Polyurethane is a multifunctional polymer material. Due to its excellent mechanical properties, wear resistance, chemical corrosion resistance and controllability, it is widely used in fields such as coatings, adhesives, elastomers, foam materials, etc. However, traditional polyurethane materials usually use organic solvents, resulting in the problem of volatile organic compound (VOC) emissions, which causes harm to the environment and human health.

[0003] Waterborne polyurethane uses water as a dispersion medium, and has the advantages of low VOC, non-toxicity, easy processing, etc., which conforms to the development trend of green chemistry. The currently developed waterborne polyurethane materials mainly rely on petroleum-based raw materials, and there are problems such as dependence on non-renewable resources and poor biodegradability. Although there are already vegetable oil-based waterborne polyurethanes developed based on castor oil and soybean oil, their mechanical properties, especially the elongation at break and tensile strength, are generally lower than those of petroleum-based products. In addition, the developed vegetable oil-based waterborne polyurethanes cannot meet the requirements of current materials for self-healing and antibacterial properties due to their simple composition structure, which limits their application in high-performance fields.

[0004] In the prior art, a rigid structure design is usually adopted to improve the mechanical properties of vegetable oil-based waterborne polyurethane, dynamic chemical bonds are introduced to achieve the self-healing performance of vegetable oil-based waterborne polyurethane, and antibacterial agents are added or antibacterial groups are introduced to achieve the antibacterial performance of vegetable oil-based waterborne polyurethane. However, the scheme of layer-by-layer superposition structure design has contradictions between mechanical properties and self-healing properties, and between mechanical properties and antibacterial properties. It is often difficult to obtain a vegetable oil-based waterborne polyurethane with both mechanical properties, self-healing properties and antibacterial properties through a single simple structure design. Summary of the Invention

[0005] The purpose of the present invention is to provide a photothermal antibacterial, self-reinforcing, self-healing vegetable oil-based waterborne polyurethane, and a preparation method and application thereof, so as to solve the technical problem in the prior art that it is difficult to obtain a vegetable oil-based waterborne polyurethane with both mechanical properties, self-healing properties and antibacterial properties.

[0006] According to the first aspect of the present invention, there is provided a photothermal antibacterial, self-reinforcing, self-healing vegetable oil-based waterborne polyurethane, which is prepared from a system composed of the following raw materials in parts by weight: 80-120 parts of castor oil, 60-80 parts of dicyclohexylmethane diisocyanate, 20-40 parts of hexamethylene diisocyanate, 20-40 parts of N-methyldiethanolamine, 20-50 parts of protocatechuic acid, 2-10 parts of metal ions, 2000-3000 parts of water and 0.5-1 part of catalyst.

[0007] The photothermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethane of the present invention uses protocatechuic acid as a proton molecule to form an ionic bond with the tertiary amine in N-methyldiethanolamine to enhance the hydrophilicity of the waterborne polyurethane segment, ensuring that the polyurethane can smoothly undergo hydrophilic-hydrophobic self-assembly during the emulsification process and transform into a waterborne polyurethane emulsion. At the same time, metal ions are introduced into the emulsion to form a composite emulsion. During the film-forming process, the metal ions and the phenolic hydroxyl groups in protocatechuic acid coordinate and self-assemble to form metal nanoclusters. This low-bond-energy coordination aggregation structure not only endows the waterborne polyurethane material with self-strengthening and self-healing properties, enabling rapid self-healing at room temperature, but also makes the waterborne polyurethane film have excellent photothermal antibacterial properties due to the formation of metal nanoclusters.

[0008] In some embodiments, the molar ratio of protocatechuic acid to metal ions is 1:0.09 to 1:0.5.

[0009] In some embodiments, the metal ions are selected from at least one of copper ions, magnesium ions, zinc ions, iron ions, and calcium ions. Specifically, when the metal ion is a copper ion, the phenolic hydroxyl group of protocatechuic acid can reduce the copper ion to a cuprous ion, and then the cuprous ion and the phenolic hydroxyl group of protocatechuic acid form metal nanoclusters through coordination self-assembly.

[0010] In some embodiments, the metal ions are added to the photothermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethane in the form of inorganic metal salts as raw materials.

[0011] In some embodiments, the inorganic metal salts are selected from at least one of sulfates, carbonates, and hydrochlorides. Specifically, the inorganic metal salts are selected from at least one of copper sulfate pentahydrate, magnesium sulfate, iron sulfate, zinc sulfate, calcium sulfate, copper chloride, iron chloride, magnesium chloride, zinc chloride, calcium chloride, basic copper carbonate, magnesium carbonate, iron carbonate, zinc carbonate, and calcium carbonate.

[0012] In some embodiments, the catalyst is an organotin catalyst; preferably, the catalyst is selected from at least one of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, and dibutyltin dioctoate.

[0013] In some embodiments, the solid content of the photothermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethane is 10% to 30%.

[0014] According to the second aspect of the present invention, there is provided a method for preparing a photothermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethane, comprising the following steps: S1. Dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and N-methyldiethanolamine react to obtain a prepolymer terminated with -NCO groups; S2, adding castor oil to the prepolymer and reacting for 0.5-1.5h to obtain a reaction system; S3, adding a catalyst to the reaction system, and when the viscosity of the prepolymer increases to the point where the prepolymer no longer has fluidity, adding an organic solvent to dilute the viscosity of the prepolymer, and continuing the reaction for 3 to 4 hours; S4, cooling the system after the reaction in S3 to room temperature, adding protocatechuic acid and N-methyldiethanolamine to the reaction system for reaction to form a protonated salt, and obtaining a polyurethane solution system; S5, adding deionized water to the polyurethane solution system for phase inversion to obtain a primary product of waterborne polyurethane; S6. The aqueous polyurethane initial product is subjected to rotary evaporation to remove the organic solvent to obtain an aqueous polyurethane emulsion, and then metal ions are added to the aqueous polyurethane emulsion to form a composite emulsion.

[0015] The preparation method of the photothermal antibacterial, self-enhancing, and self-healing plant oil-based waterborne polyurethane of the present invention utilizes coordination self-assembly to form metal nanoclusters as phase separation structures, while improving the mechanical properties of the material, giving the material rapid self-repair and photothermal antibacterial properties at room temperature. Specifically, N-methyldiethanolamine, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate are first prepolymerized to obtain a prepolymer terminated with an -NCO group, and then the green and environmentally friendly bio-based material castor oil is introduced to react with the prepolymer, and then protocatechuic acid is reacted with N-methyldiethanolamine to protonate into a salt, at which time proton transfer occurs to form an ionic bond, and the hydrophilicity of the polyurethane chain segment is enhanced to facilitate emulsification, and finally metal ions are introduced to coordinate with protocatechuic acid. The preparation method is simple, and the self-enhancement of the mechanical properties of the plant oil-based waterborne polyurethane is achieved through a single and simple structural design, and the self-healing property and photothermal antibacterial property are multi-performance.

[0016] In some embodiments, in step S1, the reaction temperature is 70-90° C., and the reaction time is 1-3 h.

[0017] In some embodiments, in step S3, the organic solvent is selected from at least one of acetone and butanone.

[0018] In some embodiments, in step S3, the amount of the organic solvent used is 30-50 mL.

[0019] In some embodiments, in step S4, the reaction time of protocatechuic acid and N-methyldiethanolamine to form a protonated salt is 0.5 to 1 h.

[0020] In some embodiments, in step S5, the mechanical rotation speed of the phase inversion is 500-700 r / min, and the time used is 2-4 hours. Specifically, the phase inversion can be emulsified by mechanical stirring.

[0021] According to a third aspect of the present invention, there is provided an application of a photothermal antibacterial, self-reinforcing, self-healing vegetable oil-based waterborne polyurethane in preparing a material having at least one of the properties of photothermal antibacterial, self-reinforcing, and self-healing. Specifically, the vegetable oil-based waterborne polyurethane can be used to prepare a wear-resistant, photothermal antibacterial coating.

[0022] The beneficial effects of the present invention are: (1) The photothermal antibacterial, self-reinforcing and self-healing plant oil-based waterborne polyurethane of the present invention uses metal ions and protocatechuic acid as raw materials. During the film-forming process, the metal ions and the phenolic hydroxyl groups in the protocatechuic acid are coordinated and self-assembled to form metal nanoclusters. This low-bond energy coordinated aggregation structure not only makes the waterborne polyurethane material have self-reinforcing and self-healing properties of mechanical properties, but also makes the waterborne polyurethane film have excellent photothermal antibacterial properties due to the formation of metal nanoclusters; (2) The present invention utilizes a simple preparation process and is easy to operate. It realizes the self-enhancement of the mechanical properties of the plant oil-based waterborne polyurethane through a single simple structural design, and has multiple properties such as self-healing properties and photothermal and antibacterial properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The appearance photos of the emulsions of the photothermal antibacterial, self-reinforcing, self-healing plant oil-based waterborne polyurethanes of Examples 1 to 3 of the present invention and the plant oil-based waterborne polyurethane of Comparative Example 1; Figure 2 FT-IR images of the photothermal antibacterial, self-reinforced and self-healing plant oil-based waterborne polyurethanes of Examples 1 to 3 of the present invention and the plant oil-based waterborne polyurethane of Comparative Example 1; Figure 3 TEM images of the photothermal antibacterial, self-reinforced, self-healing plant oil-based waterborne polyurethane of Example 1 of the present invention and the plant oil-based waterborne polyurethane film of Comparative Example 1; Figure 4 It is a mechanical property diagram of the photothermal antibacterial, self-reinforced and self-healing plant oil-based waterborne polyurethanes of Examples 1 to 3 of the present invention and the plant oil-based waterborne polyurethane film of Comparative Example 1; Figure 5 The self-healing performance test results of the photothermal antibacterial, self-reinforced, self-healing plant oil-based waterborne polyurethane film of Example 1 of the present invention and the plant oil-based waterborne polyurethane film of Comparative Example 1; Figure 6 These are the film temperature detection results and photothermal antibacterial performance test results of the photothermal antibacterial, self-reinforced, self-healing plant oil-based waterborne polyurethane film of Example 1 of the present invention and the plant oil-based waterborne polyurethane film of Comparative Example 1 after red light treatment. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings, but the implementation manners of the present invention are not limited thereto. The raw materials and reagents involved in the following examples are all commercially available.

[0025] Example 1 This example provides a photothermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethane, which is prepared through the following steps: Add 4.16 g of dicyclohexylmethane diisocyanate, 1.33 g of hexamethylene diisocyanate, and 1.89 g of N-methyldiethanolamine into a dry two-necked flask, react at 75 °C for 2 h to obtain a prepolymer, add 5.50 g of castor oil to the prepolymer, continue to react for 1 h to obtain a reaction system, then add 0.05 g of dibutyltin dilaurate as a catalyst to the reaction system, react until the reaction system no longer has fluidity, add 40 mL of butanone to dilute the concentration of the reaction system and continue to react for 3 h, then lower the temperature of the system to room temperature and add 1.46 g of protocatechuic acid, react for 1 h to obtain a polyurethane solution system; then add 131.57 g of deionized water to the polyurethane solution system, vigorously stir the polyurethane solution system at a speed of 600 r / min for 3 h to emulsify it, after removing butanone by a rotary evaporator, the obtained waterborne polyurethane emulsion has a solid content of 10%, and finally dissolve 0.23 g of copper sulfate pentahydrate in the waterborne polyurethane emulsion to obtain a photothermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethane.

[0026] Example 2 This example provides a photothermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethane, which is prepared through the following steps: Add 4.16 g of dicyclohexylmethane diisocyanate, 1.33 g of hexamethylene diisocyanate, and 1.89 g of N-methyldiethanolamine into a dry two-necked flask, react at 75 °C for 2 h to obtain a prepolymer, add 5.50 g of castor oil to the prepolymer, continue to react for 1 h to obtain a reaction system, then add 0.05 g of dibutyltin dilaurate as a catalyst to the reaction system, react until the reaction system no longer has fluidity, add 40 mL of butanone to dilute the concentration of the reaction system and continue to react for 3 h, then lower the temperature of the system to room temperature and add 1.46 g of protocatechuic acid, react for 1 h to obtain a polyurethane solution system; then add 131.57 g of deionized water to the polyurethane solution system, vigorously stir the polyurethane solution system at a speed of 600 r / min for 3 h to emulsify it, after removing butanone by a rotary evaporator, the obtained waterborne polyurethane emulsion has a solid content of 10%, and finally dissolve 0.71 g of copper sulfate pentahydrate in the waterborne polyurethane emulsion to obtain a photothermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethane.

[0027] Example 3 This example provides a photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based aqueous polyurethane, which is prepared through the following steps: Add 4.16 g of dicyclohexylmethane diisocyanate, 1.33 g of hexamethylene diisocyanate, and 1.89 g of N-methyldiethanolamine into a dry two-necked flask, react at 75 °C for 2 h to obtain a prepolymer, add 5.50 g of castor oil to the prepolymer, continue to react for 1 h to obtain a reaction system, then add 0.05 g of dibutyltin dilaurate as a catalyst to the reaction system, when the reaction system no longer has fluidity, add 40 mL of butanone to dilute the concentration of the reaction system and continue to react for 3 h, then cool the temperature of the system to room temperature and add 1.46 g of protocatechuic acid, react for 1 h to obtain a polyurethane solution system; then add 131.57 g of deionized water to the polyurethane solution system, vigorously stir at a speed of 600 r / min to emulsify the polyurethane solution system for 3 h, after removing butanone by a rotary evaporator, the solid content of the obtained aqueous polyurethane emulsion is 10%, and finally dissolve 1.18 g of copper sulfate pentahydrate in the aqueous polyurethane emulsion to obtain a photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based aqueous polyurethane.

[0028] Comparative Example 1 This comparative example provides a vegetable oil-based aqueous polyurethane, which is prepared through the following steps: Add 4.16 g of dicyclohexylmethane diisocyanate, 1.33 g of hexamethylene diisocyanate, and 1.89 g of N-methyldiethanolamine into a dry two-necked flask, react at 75 °C for 2 h to obtain a prepolymer, add 5.50 g of castor oil to the prepolymer, continue to react for 1 h to obtain a reaction system, then add 0.05 g of dibutyltin dilaurate as a catalyst to the reaction system, when the reaction system no longer has fluidity, add 40 mL of butanone to dilute the concentration of the reaction system and continue to react for 3 h, then cool the temperature of the system to room temperature and add 1.46 g of protocatechuic acid, react for 1 h to obtain a polyurethane solution system; then add 131.57 g of deionized water to the polyurethane solution system, vigorously stir at a speed of 600 r / min to emulsify the polyurethane solution system for 3 h, after removing butanone by a rotary evaporator, obtain a vegetable oil-based aqueous polyurethane, and the solid content of the obtained aqueous polyurethane emulsion is 10%.

[0029] Experimental Example 1 This experimental example observes the emulsion appearance of the photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based aqueous polyurethanes of Examples 1 to 3 and the vegetable oil-based aqueous polyurethane of Comparative Example 1.

[0030] The emulsion appearance of each vegetable oil-based aqueous polyurethane is shown in Figure 1 . From Figure 1It can be seen that the emulsions of Examples 1 to 3 presented a magenta color, while the emulsion of Comparative Example 1 showed a milky white color. The change in the emulsion color might be caused by the reduction of cupric ions in the emulsions of Examples 1 to 3 to cuprous ions by the phenolic hydroxyl groups in protocatechuic acid. The emulsions of the photo-thermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethanes of Examples 1 to 3 and the vegetable oil-based waterborne polyurethane of Comparative Example 1 all exhibited excellent stability. Among them, the stability of the emulsions of Examples 1 to 3 originated from the hydrogen bond interaction between water molecules and the phenolic hydroxyl groups of protocatechuic acid in the emulsion, which hindered the coordination of cuprous ions with the phenolic hydroxyl groups in the polyurethane molecules and thus prevented the aggregation of the waterborne polyurethane.

[0031] Experimental Example 2 In this experimental example, infrared spectroscopy characterization was performed on the films obtained after the evaporation of water from the photo-thermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethanes of Examples 1 to 3 and the vegetable oil-based waterborne polyurethane of Comparative Example 1.

[0032] The films obtained after the evaporation of water from the photo-thermal antibacterial, self-strengthening, and self-healing vegetable oil-based waterborne polyurethanes of Examples 1 to 3 and the vegetable oil-based waterborne polyurethane of Comparative Example 1 were used as samples respectively, and FT-IR spectral analysis was performed on different samples of Examples 1 to 3, Comparative Example 1, and lactobionic acid. The results are as Figure 2 shown.

[0033] From Figure 2 it can be seen that no characteristic absorption peak corresponding to the -NCO group appeared in the FT-IR spectra of all samples, indicating that the isocyanate groups in all samples had been completely consumed. At the same time, the characteristic absorption peaks of typical waterborne polyurethanes could be observed in the FT-IR spectra. The vibration absorption band at 3344 cm -1 was attributed to the -NH- of the urethane bond. The absorption bands at 2933 cm -1 and 2845 cm -1 were attributed to the vibrations of -CH -1 -CH 2 - and -CH 2 - in the fatty acid chain. The absorption band at 1714 cm 3 corresponded to the C=O stretching vibration of the urethane bond. In addition, the infrared peak at 1603 cm -1 in the infrared spectra of the examples was attributed to the benzene ring of protocatechuic acid, and the infrared peaks at 1383 cm -1 and 942 cm -1 were attributed to the phenolic hydroxyl groups of protocatechuic acid. At the same time, the infrared spectra of the products of Examples 1 to 3 showed an infrared peak at 692 cm -1 -1 ​The infrared peaks at [specific location] are attributed to the coordination structure of cuprous ions and phenolic hydroxyl groups. These typical characteristic absorption bands indicate the successful preparation of the photothermal antibacterial, self-strengthening, self-healing vegetable oil-based waterborne polyurethanes in Examples 1 to 3 and the vegetable oil-based waterborne polyurethane in Comparative Example 1. Moreover, after the copper metal ions in the waterborne polyurethanes of Examples 1 to 3 were reduced to cuprous ions by protocatechuic acid, they successfully coordinated with protocatechuic acid.

[0034] Experimental Example 3 In this experimental example, the photothermal antibacterial, self-strengthening, self-healing vegetable oil-based waterborne polyurethane of Example 1 and the vegetable oil-based waterborne polyurethane of Comparative Example 1 were dried at room temperature, and the obtained films were characterized by transmission electron microscopy (TEM). The results are as Figure 3 shown. Compared with the TEM characterization results of the vegetable oil-based waterborne polyurethane film of Comparative Example 1, it can be clearly observed that copper nanoclusters exist in the film of Example 1. This is because during the film-forming process, metal ions coordinated with protocatechuic acid to self-assemble into a nanocluster structure, and the size of the nanoclusters is between 30 and 40 nm.

[0035] Experimental Example 4 In this experimental example, the mechanical properties of the photothermal antibacterial, self-strengthening, self-healing vegetable oil-based waterborne polyurethanes in Examples 1 to 3 and the vegetable oil-based waterborne polyurethane of Comparative Example 1 were tested after curing and film-forming.

[0036] Sample preparation: The vegetable oil-based waterborne polyurethanes obtained in Examples 1 to 3 and Comparative Example 1 were dried at room temperature, and the obtained films were cut into rectangular samples with a size of 30 mm × 10 mm (length × width).

[0037] Test method: The mechanical properties of the films were measured on a tensile testing machine at an extension rate of 50 mm / min. The indexes include tensile strength, elongation at break, and toughness. In the test, more than three replicates were carried out for all samples, and the data were recorded as the mean ± standard deviation. The test results are shown in Table 1 and Figure 4 .

[0038] Table 1 Mechanical Property Test

[0039] From Table 1 and Figure 4It can be seen that the tensile strengths of the photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based waterborne polyurethanes in Examples 1 to 3 are all superior to those in Comparative Example 1, indicating that the addition of copper sulfate pentahydrate can improve the tensile strength of the vegetable oil-based waterborne polyurethane. Specifically, the tensile strength of the vegetable oil-based waterborne polyurethane film in Comparative Example 1 is 11.78 MPa, and the tensile strength of the photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based waterborne polyurethane in Example 1 is 18.77 MPa. The tensile strength of the vegetable oil-based waterborne polyurethane increases significantly with the increase in the content of copper sulfate pentahydrate. The tensile strength of the photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based waterborne polyurethane in Example 3 is 43.65 MPa, and the tensile strength is increased by 132.55% compared with that in Example 1 and by 270.54% compared with that in Comparative Example 1. Compared with the vegetable oil-based waterborne polyurethane in Comparative Example 1, the improvement in the excellent tensile strength of the photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based waterborne polyurethane films in each example benefits from the hydrogen bond interaction between the waterborne polyurethane chain molecules and the copper nanocluster structure formed by the coordination self-assembly of cuprous ions and protocatechuic acid. This in-situ phase separation structure can act as a reinforcing phase during the stretching process to achieve self-reinforcement of the mechanical properties of the film such as tensile strength.

[0040] Experimental Example 5 In this experimental example, the self-healing performance tests were carried out on the photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based waterborne polyurethane film of Example 1 and the vegetable oil-based waterborne polyurethane film of Comparative Example 1.

[0041] Test method: Cut wounds about 10 μm on the film with a blade respectively, then spray ethanol on the wounds, and finally place the film under an optical electron microscope to observe the self-healing of the film wounds.

[0042] Figure 5 The wound healing conditions of the photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based waterborne polyurethane film of Example 1 and the vegetable oil-based waterborne polyurethane film of Comparative Example 1 after being treated with ethanol are shown respectively. It can be Figure 5 seen that within 10 minutes after the photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based waterborne polyurethane film of Example 1 was treated with ethanol, a process of obvious wounds, adhesion of the wound interface, and complete healing of the wound surface occurred. However, although the width of the material wound of the vegetable oil-based waterborne polyurethane film in Comparative Example 1 gradually decreased under the stimulation of ethanol, it could not achieve complete healing finally, which might be due to the lack of coordination bonds between metal ions and protocatechuic acid in the vegetable oil-based waterborne polyurethane film of Comparative Example 1.

[0043] Experimental Example 6 In this experimental example, the photothermal antibacterial performance tests were carried out on the photothermal antibacterial, self-reinforcing, and self-healing vegetable oil-based waterborne polyurethane film of Example 1 and the vegetable oil-based waterborne polyurethane film of Comparative Example 1.

[0044] Testing method: Escherichia coli and Staphylococcus aureus were separately inoculated on the photothermal antibacterial, self-strengthening, self-healing vegetable oil-based aqueous polyurethane film of Example 1 and the vegetable oil-based aqueous polyurethane film of Comparative Example 1, and irradiated with red light at a power of 1 W / cm 2 and a wavelength of 690 nm for 3 minutes. Then, the film was immersed in sterile broth and cultured for 3.5 hours, and the bacterial solution was filtered and retained. 30 μL of the bacterial solution was evenly spread on the surface of the agar and cultured in an incubator at 37°C for 16 hours to observe the growth of bacteria.

[0045] The results of the film temperature detection and the photothermal antibacterial performance after the red light treatment are shown in Figure 6 . It can be seen from Figure 6 that the temperature of the photothermal antibacterial, self-strengthening, self-healing vegetable oil-based aqueous polyurethane film containing copper nanoclusters (Example 1) increased significantly to 245°C after being irradiated with red light for 3 minutes, and it was observed that there was basically no growth of Escherichia coli and Staphylococcus aureus on the surface of the agar after 16 hours of culture. In contrast, the temperature of the vegetable oil-based aqueous polyurethane film of Comparative Example 1 remained basically unchanged after being irradiated with red light, and Escherichia coli and Staphylococcus aureus grew vigorously on the surface of the agar after 16 hours of culture. This indicates that the copper nanoclusters endow the vegetable oil-based aqueous polyurethane with excellent photothermal conversion performance and photothermal antibacterial performance after curing into a film, and can be used in the field of photothermal antibacterial sterilization.

[0046] The above are only some embodiments of the present invention. For those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. Photothermal antibacterial, self-reinforced, self-healing plant oil-based waterborne polyurethane, characterized in that: The system is prepared from the following raw materials, which are calculated in parts by weight: 80-120 parts of castor oil, 60-80 parts of dicyclohexylmethane diisocyanate, 20-40 parts of hexamethylene diisocyanate, 20-40 parts of N-methyldiethanolamine, 20-50 parts of protocatechuic acid, 2-10 parts of metal ions, 2000-3000 parts of water and 0.5-1 part of a catalyst.

2. The photothermal antibacterial, self-reinforcing, self-healing plant oil-based waterborne polyurethane according to claim 1, characterized in that: The molar ratio of protocatechuic acid to metal ions is 1:0.09 to 1:0.

5.

3. The photothermal antibacterial, self-reinforcing, self-healing plant oil-based waterborne polyurethane according to claim 1 or 2, characterized in that: The metal ions are selected from at least one of copper ions, magnesium ions, zinc ions, iron ions and calcium ions.

4. The photothermal antibacterial, self-reinforcing, self-healing plant oil-based waterborne polyurethane according to claim 1, characterized in that: The catalyst is selected from at least one of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate and dibutyltin dioctoate.

5. The photothermal antibacterial, self-reinforcing, self-healing plant oil-based waterborne polyurethane according to claim 1, characterized in that: The solid content of the photothermal antibacterial, self-reinforcing and self-healing vegetable oil-based waterborne polyurethane is 10% to 30%.

6. The method for preparing the photothermal antibacterial, self-reinforcing and self-healing vegetable oil-based waterborne polyurethane according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and N-methyldiethanolamine are reacted to obtain a prepolymer; S2, adding castor oil to the prepolymer to react and obtain a reaction system; S3, adding a catalyst to the reaction system, and when the viscosity of the prepolymer increases to the point where the prepolymer no longer has fluidity, adding an organic solvent, and continuing the reaction; S4, cooling the system after the reaction in S3 to room temperature, adding protocatechuic acid to the reaction system for reaction, and obtaining a polyurethane solution system; S5, adding deionized water to the polyurethane solution system for phase inversion to obtain a primary product of waterborne polyurethane; S6. Rotary evaporate the initial aqueous polyurethane product to obtain an aqueous polyurethane emulsion, and then add metal ions to the aqueous polyurethane emulsion to obtain.

7. The method for preparing the photothermal antibacterial, self-reinforcing and self-healing vegetable oil-based waterborne polyurethane according to claim 6, characterized in that: In step S1, the reaction temperature is 70-90° C. and the reaction time is 1-3 h.

8. The method for preparing the photothermal antibacterial, self-reinforcing and self-healing vegetable oil-based waterborne polyurethane according to claim 6, characterized in that: In step S4, the reaction time of protocatechuic acid and N-methyldiethanolamine to form a protonated salt is 0.5-1h.

9. The method for preparing the photothermal antibacterial, self-reinforcing and self-healing vegetable oil-based waterborne polyurethane according to claim 6, characterized in that: In step S5, the mechanical rotation speed of the phase rotation is 500-700 r / min, and the time used is 2-4 hours.

10. Use of the photothermal antibacterial, self-reinforcing, self-healing vegetable oil-based waterborne polyurethane according to any one of claims 1 to 5 in the preparation of wear-resistant, photothermal antibacterial coatings.

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