Antibacterial, self-toughening, self-healing and recoverable 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 antibacterial, self-toughening, self-healing and recoverable vegetable oil-based waterborne polyurethane. The high-temperature-resistant polyurethane resin is prepared from a system consisting of the following raw materials in parts by weight: 200 to 400 parts of castor oil, 100 to 300 parts of dicyclohexylmethane diisocyanate, 70 to 150 parts of hexamethylene diisocyanate, 70 to 150 parts of N-methyldiethanolamine, 100 to 400 parts of polyalcohol acid, 7000 to 10000 parts of water and 5 to 15 parts of a catalyst. According to the invention, polyalcohol acid is used for replacing acetic acid to serve as a cationic neutralizer, so that not only can ionic bonds be formed with N-methyldiethanolamine, the hydrophilicity of a polyurethane chain segment be enhanced to ensure that the emulsification process is smoothly carried out, but also the formed quaternary ammonium salt enables the material to have antibacterial property. The polyhydric alcohol acid rich in alcoholic hydroxyl groups and carboxyl groups can be self-assembled into nanoclusters through intermolecular hydrogen bonds, so that the waterborne polyurethane material has self-healing and recoverable properties after film formation, and meanwhile, the material has high toughness and high tensile strength. The invention also discloses a preparation method and application of the vegetable oil-based waterborne polyurethane.

Description

Technical Field

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

[0002] Waterborne polyurethane uses water as the dispersion medium and has the advantages of low VOC, non-toxicity, and easy processing. It conforms to the development trend of green chemistry. The currently developed waterborne polyurethane materials mainly rely on petroleum-based raw materials. With the increasing depletion of petroleum resources and the intensification of environmental problems, the development of sustainable and environmentally friendly alternative materials has become a research hotspot.

[0003] As a renewable resource, vegetable oil has the advantages of wide sources, low price, and biodegradability, making it an ideal choice to replace petroleum-based raw materials. Through chemical modification, vegetable oil can introduce active groups such as hydroxyl groups for the synthesis of waterborne polyurethane. However, vegetable oil-based waterborne polyurethanes are generally inferior to petroleum-based waterborne polyurethanes in terms of mechanical properties, especially low toughness and single functionality, which limits their application in high-performance fields. In order to improve the toughness of vegetable oil-based waterborne polyurethane films, core-shell structured particles such as acrylic core-shell particles are often introduced into waterborne polyurethanes to improve the toughness of the material through a stress dispersion mechanism. However, this method is complicated to operate, and the effect of improving the toughness of vegetable oil-based waterborne polyurethanes is general, and it is difficult to achieve material functional diversity in the design of this method. Therefore, it is urgent to design vegetable oil-based waterborne polyurethanes with improved toughness and multifunctionality. Summary of the invention

[0004] The purpose of the present invention is to provide an antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane and a preparation method and application thereof, so as to solve the technical problems of low toughness and single functionality of vegetable oil-based waterborne polyurethane in the prior art.

[0005] The first aspect of the present invention provides an antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane, which is prepared from a system consisting of the following raw materials in parts by weight: 200-400 parts of castor oil, 100-300 parts of dicyclohexylmethane diisocyanate, 70-150 parts of hexamethylene diisocyanate, 70-150 parts of N-methyldiethanolamine, 100-400 parts of polyol acid, 7000-10000 parts of water and 5-15 parts of catalyst.

[0006] The antibacterial, self-toughening, self-healing and recyclable vegetable oil-based waterborne polyurethane of the present invention uses a polyol acid rich in alcohol hydroxyl groups and carboxyl groups as a raw material. The polyol acid, as a small molecule neutralizer, can not only form an ionic bond with the tertiary amine of N-methyldiethanolamine to enhance the hydrophilicity of the polyurethane chain segment, thereby achieving smooth hydrophilic and hydrophobic assembly of the waterborne polyurethane into a waterborne polyurethane emulsion during the emulsification process, but also the alcohol hydroxyl groups and carboxyl groups on the polyol acid can self-assemble to form nanoclusters through intermolecular hydrogen bonding during the film-forming process of the antibacterial, self-toughening, self-healing and recyclable vegetable oil-based waterborne polyurethane to enhance the toughness of the vegetable oil-based waterborne polyurethane itself.

[0007] In some embodiments, the polyol acid contains 1 to 9 alcoholic hydroxyl groups and 1 to 4 carboxyl groups.

[0008] In some embodiments, the polyol acid includes at least one of lactic acid, mucic acid, sialic acid, tartaric acid, citric acid, and D-gluconic acid.

[0009] In some embodiments, the catalyst is an organic tin catalyst; preferably, the catalyst is selected from at least one of dibutyltin dilaurate, dibutyltin diacetate, and dibutyltin dioctoate.

[0010] In some embodiments, the molar ratio of the polyol acid to N-methyldiethanolamine is 0.6:1 to 1.1:1.

[0011] In some embodiments, the antimicrobial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane has a solid content of 10% to 30%.

[0012] The second aspect of the present invention provides a method for preparing an antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane, comprising the following steps: S1. reacting dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and N-methyldiethanolamine at 80-85° C. for 0.5-2 h to obtain a prepolymer; S2, adding castor oil to the prepolymer, reacting for 1.5-2h to obtain a reaction system; S3, adding a catalyst to the reaction system, and reacting until the reaction system no longer has fluidity; S4, adding an organic solvent to the reaction system, reacting for 1.5-2h, cooling to room temperature, and obtaining a polyurethane solution system; S5. Dissolve the polyol acid in water to obtain an aqueous solution of the polyol acid, add the aqueous solution of the polyol acid into the polyurethane solution system, emulsify, and then remove the organic solvent by rotary evaporation to obtain.

[0013] The antibacterial, self-toughening, self-healing and recyclable vegetable oil-based waterborne polyurethane of the present invention firstly prepolymerizes N-methyldiethanolamine, dicyclohexylmethane diisocyanate and hexamethylene diisocyanate to obtain a prepolymer terminated with -NCO groups, then introduces green and environmentally friendly bio-based material castor oil, and utilizes polyol acid to transfer protons with N-methyldiethanolamine to form ionic bonds, which not only enhances the hydrophilicity of the polyurethane chain segment to facilitate emulsification, but also allows the polyol acid to self-assemble to form nanoclusters, and the preparation method is simple.

[0014] In some embodiments, in step S4, the organic solvent is selected from at least one of acetone and butanone.

[0015] In some embodiments, in step S4, the amount of the organic solvent used is 20-40 mL.

[0016] In some embodiments, in step S5, the rotation speed used for emulsification is 800-1000 r / min, and the emulsification time is 1-2 h.

[0017] The third aspect of the present invention provides the use of antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane, which can be used to prepare coatings, antibacterial materials, and adhesives.

[0018] In some embodiments, the antibacterial, self-toughening, self-healing, recyclable plant oil-based waterborne polyurethane can be used to prepare coatings, antibacterial materials, and adhesives with recyclability, self-healing ability, high tensile strength, and high toughness.

[0019] The beneficial effects of the present invention are: (1) The antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane of the present invention uses polyol acid to replace traditional acetic acid as a cationic neutralizer, which can not only form an ionic bond with N-methyldiethanolamine to enhance the hydrophilicity of the polyurethane chain segment to ensure a smooth emulsification process, but also the polyol acid can self-assemble into nanoclusters through intermolecular hydrogen bonds during the film-forming process due to its rich alcohol hydroxyl and carboxyl groups. This in-situ phase separation structure can improve the toughness of the waterborne polyurethane itself, so that the waterborne polyurethane material has high toughness and high tensile strength; (2) The present invention utilizes a simple preparation process and is easy to operate. The prepared waterborne polyurethane has good antibacterial effect after film formation, and has self-healing and recyclable properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The emulsion appearance photos of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethanes of Examples 1-3 of the present invention and the vegetable oil-based waterborne polyurethane of Comparative Example 1; Figure 2FT-IR images of the antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethanes of Examples 1-3 of the present invention, the vegetable oil-based waterborne polyurethane of Comparative Example 1, and lactobionic acid; Figure 3 TEM images of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane of Example 1 of the present invention and the vegetable oil-based waterborne polyurethane film of Comparative Example 1; Figure 4 The mechanical properties diagram of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethanes of Examples 1-3 of the present invention and the vegetable oil-based waterborne polyurethane film of Comparative Example 1; Figure 5 The self-healing performance test results of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane films of Examples 1-3 of the present invention and the vegetable oil-based waterborne polyurethane film of Comparative Example 1; Figure 6 The recovery of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film of Example 1 of the present invention; Figure 7 This is a diagram showing the antibacterial effect of the antibacterial, self-toughening, self-healing, recyclable plant oil-based waterborne polyurethane of Example 1 of the present invention and the plant oil-based waterborne polyurethane film of Comparative Example 1. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings, but the embodiments of the present invention are not limited thereto. The raw materials and reagents involved in the following examples can all be obtained from commercial channels.

[0022] Example 1 This embodiment provides an antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane, which is prepared by the following steps: At 80°C, 1.70 g of dicyclohexylmethane diisocyanate, 1.09 g of hexamethylene diisocyanate and 1.03 g of N-methyldiethanolamine was added into a dry two-necked flask and reacted for 2 hours to obtain a prepolymer. 3.00 g of castor oil was added to the prepolymer and the reaction was continued for 2 hours to obtain a reaction system. Then 0.05 g of dibutyltin dilaurate was added into the reaction system as a catalyst. When the reaction system no longer had fluidity, 30 mL of butanone was added to dilute the concentration of the reaction system and the reaction was continued for 2 hours. Subsequently, the temperature of the reaction system was lowered from 80°C to room temperature to obtain a polyurethane solution system. Then 1.86 g of lactobionic acid was dissolved in 78.22 g of deionized water to obtain an aqueous solution of lactobionic acid and the aqueous solution of lactobionic acid was added to the polyurethane solution system. The polyurethane solution system was emulsified for 2 hours under vigorous stirring at 800-1000 r / min. After removing the butanone by a rotary evaporator, an antibacterial, self-toughening, self-healing and recyclable vegetable oil-based waterborne polyurethane was obtained. The solid content of the obtained waterborne polyurethane emulsion was 10%.

[0023] Example 2 This embodiment provides an antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane, which is prepared by the following steps: At 80°C, 1.70 g of dicyclohexylmethane diisocyanate, 1.09 g of hexamethylene diisocyanate and 1.03 g of N-methyldiethanolamine was added into a dry two-necked flask, and the reaction was carried out for 2 hours to obtain a prepolymer. 3.00 g of castor oil was added into the prepolymer, and the reaction was continued for 2 hours to obtain a reaction system. Then, 0.05 g of dibutyltin dilaurate was added into the reaction system as a catalyst, and the reaction was continued until the reaction system no longer had fluidity. Then, 30 mL of butanone was added to dilute the concentration of the reaction system and the reaction was continued for 2 hours. Subsequently, the temperature of the reaction system was lowered from 80°C to room temperature to obtain a polyurethane solution system. Then, 2.79 g of lactobionic acid was dissolved in 86.60 g of deionized water to obtain an aqueous solution of lactobionic acid, and the aqueous solution of lactobionic acid was added into the polyurethane solution system. The polyurethane solution system was emulsified for 2 hours under vigorous stirring at 800-1000 r / min. After removing the butanone by a rotary evaporator, an antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane was obtained. The solid content of the obtained waterborne polyurethane emulsion was 10%.

[0024] Example 3 This embodiment provides an antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane, which is prepared by the following steps: At 80°C, 1.70 g of dicyclohexylmethane diisocyanate, 1.09 g of hexamethylene diisocyanate and 1.03 g of N-methyldiethanolamine was added into a dry two-necked flask, and the reaction was carried out for 2 hours to obtain a prepolymer. 3.00 g of castor oil was added into the prepolymer, and the reaction was continued for 2 hours to obtain a reaction system. Then, 0.05 g of dibutyltin dilaurate was added into the reaction system as a catalyst, and the reaction was continued until the reaction system no longer had fluidity. Then, 30 mL of butanone was added to dilute the concentration of the reaction system and the reaction was continued for 2 hours. Subsequently, the temperature of the reaction system was lowered from 80°C to room temperature to obtain a polyurethane solution system. Then, 3.41 g of lactobionic acid was dissolved in 92.19 g of deionized water to obtain an aqueous solution of lactobionic acid, and the aqueous solution of lactobionic acid was added into the polyurethane solution system. The polyurethane solution system was emulsified for 2 hours under vigorous stirring at 800-1000 r / min. After removing the butanone by a rotary evaporator, an antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane was obtained. The solid content of the obtained waterborne polyurethane emulsion was 10%.

[0025] Comparative Example 1 This comparative example provides a vegetable oil-based waterborne polyurethane, which is prepared by the following steps: 1.70 g of dicyclohexylmethane diisocyanate, 1.09 g of hexamethylene diisocyanate and 1.03 g of N-methyldiethanolamine were added to a dry two-necked flask at 80° C., and reacted for 2 h at 80° C. to obtain a prepolymer. 3.00 g of castor oil was added to the prepolymer, and the reaction was continued for 2 h to obtain a reaction system. Then 0.05 g of dibutyltin dilaurate was added to the reaction system as a catalyst, and the reaction was continued until the reaction system no longer had fluidity. 30 mL of butanone was added to dilute the concentration of the reaction system and the reaction was continued for 2 h. Subsequently, the temperature of the reaction system was lowered from 80° C. to room temperature to obtain a polyurethane solution system. Then 0.31 g of acetic acid was dissolved in 64.27 g of deionized water to obtain an aqueous solution of acetic acid, and the aqueous solution of acetic acid was added to the polyurethane solution system. The polyurethane solution system was emulsified for 2 h under vigorous stirring at 800-1000 r / min. After removing the butanone by a rotary evaporator, a vegetable oil-based water-based polyurethane was obtained. The solid content of the obtained water-based polyurethane emulsion was 10%.

[0026] Experimental Example 1 In this experimental example, the antibacterial, self-toughening, self-healing, and recyclable plant oil-based waterborne polyurethanes of Examples 1-3 and the plant oil-based waterborne polyurethane of Comparative Example 1 were observed to study the effect of lactobionic acid content on the appearance of the plant oil-based waterborne polyurethane emulsion.

[0027] The emulsion appearance photos of the antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethanes of Examples 1-3 and the vegetable oil-based waterborne polyurethane of Comparative Example 1 are as follows: Figure 1 As shown. Figure 1It can be seen that the emulsions of Examples 1-3 and Comparative Example 1 all present a translucent or transparent appearance. The aqueous polyurethane emulsions of Example 1 and Comparative Example 1 are prepared from the same molar amount of lactobionic acid and acetic acid, respectively, and the appearance color and transparency of the two emulsions are similar. As the lactobionic acid content increases, the lactobionic acid content in Examples 2 and 3 increases, the hydrophilicity of the polyurethane chain segment increases, and the emulsion particle size is smaller, so the emulsions of Examples 2 and 3 show higher transparency.

[0028] Experimental Example 2 In this experimental example, the antibacterial, self-toughening, self-healing, and recyclable plant oil-based waterborne polyurethanes of Examples 1-3 and the plant oil-based waterborne polyurethane and lactobionic acid of Comparative Example 1 were characterized by infrared spectroscopy.

[0029] The films obtained after evaporation of water from the antibacterial, self-toughening, self-healing, and recyclable plant oil-based waterborne polyurethanes of Examples 1-3 and the plant oil-based waterborne polyurethanes of Comparative Example 1 were used as samples, respectively. FT-IR spectral analysis was performed on the different samples of Examples 1-3, Comparative Example 1, and lactobionic acid. The results are as follows: Figure 2 As shown. Figure 2 It can be seen that the FT-IR spectrum of the sample is at 2270 cm -1 There is no characteristic absorption peak corresponding to the -NCO group at any place, which indicates that the isocyanate group in the reactant has been completely consumed. At the same time, the characteristic absorption peak of typical waterborne polyurethane can be observed in the FT-IR spectrum, 3344 cm -1 The vibration absorption band at 2933 cm-1 is attributed to the -NH- of the carbamate bond. -1 and 2845 cm -1 The absorption band at 1714 cm -1 The absorption band at 3000-3700 cm -1 The broad peak at 1685-1900 cm -1 The infrared peak at 900~1190 cm -1 The large broad peak at belongs to COC, and the infrared peaks of these characteristic groups contained in lactobionic acid all appear in the FT-IR spectra of the samples of Examples 1-3. These typical characteristic absorption bands indicate that the antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethanes of Examples 1-3 and the vegetable oil-based waterborne polyurethane of Comparative Example 1 are successfully prepared.

[0030] Experimental Example 3 In this experimental example, the antibacterial, self-toughening, self-healing, and recyclable plant oil-based waterborne polyurethane of Example 1 and the plant oil-based waterborne polyurethane of Comparative Example 1 were dried at room temperature, and the films obtained after drying were characterized by transmission electron microscopy (TEM). The results are as follows: Figure 3 Compared with the TEM characterization results of the vegetable oil-based waterborne polyurethane film of Comparative Example 1, it can be clearly observed that lactobionic acid clusters exist in the film of Example 1. This is because the lactobionic acid rich in hydroxyl and carboxyl groups self-assembles into nanoclusters through intermolecular hydrogen bonding during the film formation process.

[0031] Experimental Example 4 In this experimental example, mechanical properties of the antibacterial, self-toughening, self-healing, recyclable plant oil-based waterborne polyurethanes of Examples 1-3 and the plant oil-based waterborne polyurethane of Comparative Example 1 were tested after curing into films.

[0032] Sample preparation: The vegetable oil-based waterborne polyurethane obtained in Examples 1-3 and Comparative Example 1 was dried at room temperature, and the film obtained after drying was cut into rectangular samples of 30 mm×10 mm (length×width).

[0033] Test method: The sample was tested on a tensile machine at an extension rate of 50 mm / min to measure the mechanical properties of the film, including tensile strength, elongation at break and toughness. All samples were tested more than three times in the test, and the data were recorded as the average value ± standard deviation. The test results are shown in Table 1 and Figure 4 .

[0034] Table 1 Mechanical properties test

[0035] As shown in Table 1, the tensile strength and toughness of the vegetable oil-based waterborne polyurethane film of Comparative Example 1 are 2.15 MPa and 2.71 MJ·m -3 The mechanical properties test results of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane films of Examples 1-3 are significantly better than those of the film of Comparative Example 1 in all indicators. Compared with the film of Comparative Example 1, the tensile strength of the film obtained from the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane of Example 1 is 13 times that of the film of Comparative Example 1, and the toughness is 43 times that of the film of Comparative Example 1. Among them, with the increase of lactobionic acid content, the elongation at break and toughness of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film decrease, and the tensile strength increases, and the tensile strength reaches more than 40MPa at the highest. The excellent mechanical properties are due to the nanocluster structure formed by the self-assembly of hydroxyl and carboxyl groups of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane during the film-forming process through intermolecular hydrogen bonding. This in-situ phase separation structure can dissipate energy through structural dissociation during the stretching process to achieve the effect of enhancing toughness.

[0036] Experimental Example 5 In this experimental example, the self-healing performance of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane films of Examples 1-3 and the vegetable oil-based waterborne polyurethane film of Comparative Example 1 was tested.

[0037] Test method: Use a blade to cut wounds of about 5 μm on the film, then spray ethanol on the wounds, and finally place the film under an optical electron microscope to observe the self-healing state of the film wounds.

[0038] Figure 5 The wound healing conditions of the antibacterial, self-toughening, self-healing, and recyclable plant oil-based waterborne polyurethane films of Examples 1-3 and the plant oil-based waterborne polyurethane film obtained in Comparative Example 1 after being treated with ethanol are shown respectively. Figure 5 It can be observed that the wound width of the vegetable oil-based waterborne polyurethane film of comparative example 1 will be reduced under the stimulation of ethanol, but it cannot be completely healed in the end. In contrast, the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane films of Examples 1-3 show obvious wound appearance, wound interface adhesion, and complete healing of the wound surface within 15 minutes after ethanol treatment. Specifically, the wound of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film of Example 1 is completely healed after 9 minutes of ethanol treatment, the wound of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film of Example 2 is completely healed after 12 minutes of ethanol treatment, and the wound of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film of Example 3 is completely healed after 15 minutes of ethanol treatment, indicating that with the increase of lactobionic acid content, the wound healing time of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film also increases, which may be related to the compactness of the internal structure of the polyurethane. Thus, the present invention has found that the liquid small molecule solvent ethanol rich in hydrogen bond donors and acceptors has the effect of promoting the rapid healing of wounds in the antibacterial, self-toughening, self-healing and recyclable plant oil-based waterborne polyurethane film. This is because, compared with the plant oil-based waterborne polyurethane film lacking hydrogen bond self-assembled nanoclusters, the antibacterial, self-toughening, self-healing and recyclable plant oil-based waterborne polyurethane films of Examples 1-3 are formed in ethanol through intermolecular hydrogen bonding to self-assemble into nanoclusters to achieve self-healing of wounds. At this time, hydrogen bonds as a unique non-covalent dynamic bond give the film excellent self-healing properties.

[0039] Experimental Example 6 In this experimental example, the antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane film of Example 1 and the vegetable oil-based waterborne polyurethane film of Comparative Example 1 were tested for their recyclability.

[0040] The vegetable oil-based waterborne polyurethane film of Comparative Example 1 was cut into fragments, and then the fragments were hot pressed at 140° C. and 20 MPa. It was found that the vegetable oil-based waterborne polyurethane film was difficult to recover from the fragment state into a complete film by hot pressing.

[0041] The antibacterial, self-toughening, self-healing, recyclable plant oil-based waterborne polyurethane film of Example 1 was cut into pieces, and then the pieces were hot pressed at 140°C and 20MPa, and the above process was repeated 5 times. The recyclability test results of the antibacterial, self-toughening, self-healing, recyclable plant oil-based waterborne polyurethane film of Example 1 are shown in Figure 6 It can be observed that the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film of Example 1 can be transformed from a debris state into a complete film through hot pressing, indicating that the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film of Example 1 has good recyclability compared with the film of Comparative Example 1. After 5 repeated shearing and hot pressing, the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film of Example 1 can still maintain its initial state, which indicates that the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film with hydrogen-bonded self-assembled nanoclusters can still rearrange the polymer molecular chains to restore the initial state through the dissociation and recombination of hydrogen bonds after multiple shearing and hot pressing, showing excellent multiple recycling potential. Therefore, the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film of the present invention can solve the problem that thermosetting materials are difficult to recycle and reuse, and extend the service life of thermosetting polyurethane materials.

[0042] Experimental Example 7 In this experimental example, the antibacterial properties of the antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane film of Example 1 and the vegetable oil-based waterborne polyurethane film of Comparative Example 1 were tested.

[0043] Test method: The antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane film of Example 1 and the vegetable oil-based waterborne polyurethane film of Comparative Example 1 were irradiated under 365nm ultraviolet light for 30 minutes, and then the films were soaked in a PBS solution with a pH of 7 for 30 minutes for use; the films were co-cultured with 1 mL of Staphylococcus aureus solution and Escherichia coli solution (the concentration of the solution was 0.5 McFarland turbidity) for 3.5 hours, respectively, and then filtered, 30 μL of the solution was evenly spread on the agar surface, and cultured in a 37°C incubator for 16 hours to observe the bacterial growth.

[0044] Antibacterial performance test results Figure 7 As shown. Figure 7It can be seen that there are still strains growing on the agar surface treated with the vegetable oil-based waterborne polyurethane film of Comparative Example 1, indicating that the antibacterial effect of the vegetable oil-based waterborne polyurethane film on Escherichia coli and Staphylococcus aureus is weak, which may be because the acetic acid volatilizes during the drying and film-forming process of the vegetable oil-based waterborne polyurethane, and the quaternary ammonium ion pairs inside the material dissociate. No strains are observed on the agar surface treated with the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film of Example 1, indicating that the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film exhibits excellent antibacterial effects on Escherichia coli and Staphylococcus aureus, which is attributed to the fact that the nanoclusters of the antibacterial, self-toughening, self-healing, and recyclable vegetable oil-based waterborne polyurethane film of Example 1 contain a large number of quaternary ammonium ion pairs, and these quaternary ammonium ions have excellent antibacterial effects on Escherichia coli and Staphylococcus aureus.

[0045] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. Antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane, characterized in that: The system is prepared from the following raw materials in parts by weight: 200-400 parts of castor oil, 100-300 parts of dicyclohexylmethane diisocyanate, 70-150 parts of hexamethylene diisocyanate, 70-150 parts of N-methyldiethanolamine, 100-400 parts of polyol acid, 7000-10000 parts of water and 5-15 parts of catalyst.

2. The antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane according to claim 1, characterized in that: The polyol acid includes at least one of lactic acid, mucic acid, sialic acid, tartaric acid, citric acid, and D-gluconic acid.

3. The antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane according to claim 1 or 2, characterized in that: The molar ratio of the polyol acid to the N-methyldiethanolamine is 0.6:1-1.1:

1.

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

5. The antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane according to claim 1, characterized in that: The antibacterial, self-toughening, self-healing and recyclable vegetable oil-based waterborne polyurethane has a solid content of 10%-30%.

6. The method for preparing the antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. reacting dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and N-methyldiethanolamine at 80-85° C. for 0.5-2 h to obtain a prepolymer; S2, adding castor oil to the prepolymer, reacting for 1.5-2h to obtain a reaction system; S3, adding a catalyst to the reaction system, and reacting until the reaction system no longer has fluidity; S4, adding an organic solvent to the reaction system, reacting for 1.5-2h, cooling to room temperature, and obtaining a polyurethane solution system; S5. Dissolve the polyol acid in water to obtain an aqueous solution of the polyol acid, add the aqueous solution of the polyol acid into the polyurethane solution system, emulsify, and then remove the organic solvent by rotary evaporation to obtain.

7. The method for preparing the antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane according to claim 6, characterized in that: In step S4, the organic solvent is selected from at least one of acetone and butanone; the amount of the organic solvent is 20-40 mL.

8. The method for preparing the antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane according to claim 6, characterized in that: In step S5, the rotation speed used for emulsification is 800-1000 r / min, and the emulsification time is 1-2 h.

9. Use of the antibacterial, self-toughening, self-healing, recyclable vegetable oil-based waterborne polyurethane according to any one of claims 1 to 5 in the preparation of coatings, antibacterial materials, and adhesives.

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