Antibacterial and ultraviolet resistant polyurethane coating
By grafting phytic acid and chitosan into polyurethane coatings, and utilizing the complexation and improved compatibility of MXene with Zn ions, the problems of oxidative discoloration and bacterial erosion in polyurethane coatings were solved, achieving long-lasting antibacterial and UV-resistant properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 晋江市福大科教园区发展中心
- Filing Date
- 2023-03-17
- Publication Date
- 2026-05-12
Smart Images
Figure CN118667427B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of materials preparation, specifically relating to an antibacterial and UV-resistant polyurethane coating. Background Technology
[0002] Polyurethane (PU) is a high-performance polymer material with advantages such as a wide hardness range, good mechanical properties, wear resistance, and oil resistance. It is widely used in food packaging, architectural coatings, adhesives, and other fields. However, polyurethane is prone to yellowing due to oxidation during use, and it is also susceptible to bacterial attack in dark and humid environments, causing changes in the appearance of the coating, affecting both aesthetics and performance.
[0003] MXene has a large specific surface area, is easy to chemically manipulate and functionalize, and has the potential to load different antimicrobial functional groups. Therefore, it is regarded as a high-potential antimicrobial agent with high stability and long life cycle.
[0004] ZnO, as an inorganic antibacterial agent, has advantages over similar antibacterial agents due to its non-toxicity, stability, and broad-spectrum and long-lasting antibacterial effects. Simultaneously, ZnO has a strong ability to absorb and scatter ultraviolet light, making it suitable as an anti-UV aging agent. However, pure ZnO has drawbacks such as easy aggregation and difficulty in recycling; therefore, a carrier is usually required during ZnO formation. Phytic acid has excellent metal ion complexing ability and can provide active sites for Zn ions.
[0005] Chitosan, a natural cationic linear polysaccharide, is widely found in the cell walls of algae and fungi, as well as in the shells of crustaceans. Chitosan and its enzymatic degradation products can interact safely with living cells without adverse effects, and can effectively control the growth and reproduction of microorganisms such as bacteria and fungi. Summary of the Invention
[0006] The purpose of this invention is to provide an antibacterial and UV-resistant polyurethane coating, which utilizes the abundant functional groups on the surface of MXene to graft phytic acid. The complexing ability of phytic acid provides a site for Zn ions, and chitosan is then grafted to increase its compatibility with the polyurethane matrix. As a result, the prepared polyurethane coating can effectively mitigate the problem of mechanical property degradation after UV exposure while also having a long-lasting antibacterial effect.
[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:
[0008] An antibacterial and UV-resistant polyurethane coating, by weight, comprises the following raw materials: 30-45 parts of polycaprolactone diol, 10-20 parts of polysorbate adipate diol, 18-25 parts of polytetrahydrofuran diol, 5-25 parts of composite antibacterial agent, 0.05-0.1 parts of antioxidant, 10-20 parts of 4,4'-diphenylmethane diisocyanate (MDI), and 0.5-1 parts of catalyst.
[0009] Furthermore, the number-average molecular weight of the polycaprolactone diol is 200-5000.
[0010] Furthermore, the number-average molecular weight of the poly(ricinoleic adipate) diol is 500-3000.
[0011] Furthermore, the number-average molecular weight of the polytetrahydrofuran diol is 500-3000.
[0012] Furthermore, the antioxidant is designated as 1010 or 1076.
[0013] Furthermore, the catalyst is one of bis(2-morpholinodiethyl) ether, dibutyltin dilaurate, and tin isooctanoate.
[0014] Furthermore, the preparation of the composite antibacterial agent includes the following steps:
[0015] (1) Preparation of monolayer MXene: 1.56g LiF and 20mL HCl solution with a concentration of 9mol / L were added to a polytetrafluoroethylene reactor and reacted at 40℃ for 15min. Then, 1g Ti3AlC2 was slowly added to the reactor in small amounts several times. The reaction was stirred at 40-45℃ and 500rpm for 48h. After centrifugation and washing until pH=6, the precipitate was separated by filtration. The precipitate was further centrifuged and washed until a viscous precipitate appeared and the upper liquid turned black. The viscous precipitate was poured into a three-necked round-bottom flask, deionized water was added and nitrogen was filled and sealed. Then it was placed in an ultrasonic machine at 5℃ and sonicated for 1.5h. After the end, it was centrifuged to obtain a dark green dispersion. The precipitate obtained after filtration was vacuum dried at 40℃ for 2h. After removal, it was ground into powder to obtain monolayer MXene, and then placed in a desiccator and sealed for storage.
[0016] (2) Preparation of composite antibacterial agent: 16 mg of monolayer MXene was placed in 100 mL of deionized water and stirred at 30 °C for 30 min to disperse it evenly. Then, 100 mL of zinc acetate solution with a concentration of 0.06 mol / L was added and stirred for another 30 min. Then, 100 mL of phytic acid solution with a concentration of 0.1 mol / L was added dropwise at a rate of 2 drops / second and stirred for another 6 h. Then, 100 mL of chitosan dispersion with a concentration of 20 g / L was added. The mixture was heated to 40 °C and stirred for 24 h. After filtration, washing and drying, the product was obtained.
[0017] Furthermore, the preparation steps of the polyurethane coating are as follows:
[0018] a) Add polycaprolactone diol, polysorbate ricinoleate diol, polytetrahydrofuran diol and antioxidant to a three-necked flask and stir until homogeneous. Heat to 120℃-130℃ and dehydrate for 2 hours under vacuum <100Pa.
[0019] b) Cool down to 70℃-80℃, add MDI, and stir the reaction for 1-2 hours at 70℃-80℃ and vacuum degree <100Pa.
[0020] c) After releasing the vacuum, add the catalyst and composite antibacterial agent, then heat to 90°C and stir rapidly for 10 minutes under a vacuum of <100Pa.
[0021] d) The material is rapidly discharged and packaged under nitrogen protection.
[0022] The significant advantages of this invention are:
[0023] This invention utilizes the abundant functional groups on the surface of MXene to graft phytic acid. Through the complexation of metal ions by phytic acid, a large number of attachment sites are provided for zinc ions. Then, through ion exchange between chitosan and phytic acid, chitosan is grafted onto the surface of the composite antibacterial agent. With the slow release of zinc ions and the oxidation of MXene, the antibacterial duration is enhanced. At the same time, the abundant hydroxyl and amino groups on the chitosan segments can react and connect with excess isocyanate groups in the polyurethane matrix, improving the compatibility between the antibacterial agent and the matrix. They can also interact with metal ions that play a key role in microbial growth, further effectively inhibiting microbial growth. Thus, the prepared polyurethane coating has both UV aging resistance and good long-lasting antibacterial properties. Attached Figure Description
[0024] Figure 1 This is a SEM image of the MXene prepared in Example 2.
[0025] Figure 2 This is a SEM image of the composite antibacterial agent prepared in Example 2. Figure 1 As can be seen from the comparison, the modified MXene surface is uniformly loaded with a large number of chitosan particles.
[0026] Figure 3 The infrared spectra of the composite antibacterial agents prepared in Example 2 and Comparative Example 1 are shown. In the figure, 1380 cm⁻¹... -1 The characteristic peak at 1022 cm⁻¹ corresponds to the P-OH bond. -1 The characteristic peak at 1600 cm⁻¹ indicates that the reaction between phytic acid and chitosan produces POC bonds. -1The presence of NH bonds indicates that the amino groups on the chitosan segments did not fully participate in the reaction. (549 cm) -1 The presence of Ti-O bonds indicates that MXene successfully complexed with the antibacterial agent. Detailed Implementation
[0027] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.
[0028] Example 1
[0029] The specific preparation steps of an antibacterial and UV-resistant polyurethane coating are as follows:
[0030] (1) Preparation of monolayer MXene: 1.56 g LiF and 20 mL of 9 mol / L HCl solution were added to a polytetrafluoroethylene reactor and reacted at 40 °C for 15 min. Then, 1 g Ti3AlC2 was slowly added to the reactor in small amounts several times and reacted at 40 °C and 500 rpm for 48 h. The resulting slurry was centrifuged and washed until pH=6. The precipitate was then separated by vacuum filtration. The precipitate was then centrifuged and washed again until a viscous precipitate appeared and the upper liquid turned black. The viscous precipitate was poured into a three-necked round-bottom flask, 50 mL of deionized water was added, the flask was filled with nitrogen and sealed, and the flask was placed in an ultrasonic machine at 5 °C for 1.5 h. After the ultrasonic treatment, the flask was centrifuged at 2500 rpm for 30 min to obtain a dark green dispersion. The precipitate was separated by vacuum filtration and dried at 40 °C for 2 h. The precipitate was then ground into powder to obtain monolayer MXene, which was then placed in a desiccator and sealed for storage.
[0031] (2) Preparation of composite antibacterial agent: Take 16 mg of the above monolayer MXene, disperse it in 100 mL of deionized water, stir at 30 °C for 30 min to make it evenly dispersed, then add 100 mL of zinc acetate solution with a concentration of 0.06 mol / L, continue stirring for 30 min, then add 100 mL of phytic acid solution with a concentration of 0.1 mol / L at a rate of 2 drops / second, continue stirring for 6 h, then add 100 mL of chitosan dispersion with a concentration of 20 g / L, heat to 40 °C and stir for 24 h, then filter, wash and dry for later use.
[0032] (3) Preparation of polyurethane coatings:
[0033] a) By weight, add 37 parts of polycaprolactone diol, 15 parts of polysorbate ricinoleate diol, 22 parts of polytetrahydrofuran diol and 0.05 parts of antioxidant 1010 into a three-necked flask and stir until homogeneous. Heat to 120°C and dehydrate for 2 hours under a vacuum of <100Pa.
[0034] b) Cool down to 70°C, add 14 parts of MDI, and stir the reaction for 1 hour at 70°C and a vacuum degree <100Pa.
[0035] c) After releasing the vacuum, add 0.5 parts of bis(2-morpholinodiethyl) ether and 5 parts of compound antibacterial agent, then heat to 90°C and stir rapidly for 10 min under a vacuum of <100 Pa.
[0036] d) The product is obtained by rapid discharge and packaging under nitrogen protection, and the prepared product sample is marked as A1.
[0037] Example 2
[0038] The specific preparation steps of an antibacterial and UV-resistant polyurethane coating are as follows:
[0039] (1) Preparation of monolayer MXene: 1.56 g LiF and 20 mL of 9 mol / L HCl solution were added to a polytetrafluoroethylene reactor and reacted at 40 °C for 15 min. Then, 1 g Ti3AlC2 was slowly added to the reactor in small amounts several times and reacted at 40 °C and 500 rpm for 48 h. The resulting slurry was centrifuged and washed until pH=6. The precipitate was then separated by vacuum filtration. The precipitate was then centrifuged and washed again until a viscous precipitate appeared and the upper liquid turned black. The viscous precipitate was poured into a three-necked round-bottom flask, 50 mL of deionized water was added, the flask was filled with nitrogen and sealed, and the flask was placed in an ultrasonic machine at 5 °C for 1.5 h. After the ultrasonic treatment, the flask was centrifuged at 2500 rpm for 30 min to obtain a dark green dispersion. The precipitate was separated by vacuum filtration and dried at 40 °C for 2 h. The precipitate was then ground into powder to obtain monolayer MXene, which was then placed in a desiccator and sealed for storage.
[0040] (2) Preparation of composite antibacterial agent: Take 16 mg of the above monolayer MXene, disperse it in 100 mL of deionized water, stir at 30 °C for 30 min to make it evenly dispersed, then add 100 mL of zinc acetate solution with a concentration of 0.06 mol / L, continue stirring for 30 min, then add 100 mL of phytic acid solution with a concentration of 0.1 mol / L at a rate of 2 drops / second, continue stirring for 6 h, then add 100 mL of chitosan dispersion with a concentration of 20 g / L, heat to 40 °C and stir for 24 h, then filter, wash and dry for later use.
[0041] (3) Preparation of polyurethane coatings:
[0042] a) By weight, add 37 parts of polycaprolactone diol, 15 parts of polysorbate ricinoleate diol, 22 parts of polytetrahydrofuran diol and 0.05 parts of antioxidant 1010 into a three-necked flask and stir until homogeneous. Heat to 120°C and dehydrate for 2 hours under a vacuum of <100Pa.
[0043] b) Cool down to 70°C, add 14 parts of MDI, and stir the reaction for 1 hour at 70°C and a vacuum degree <100Pa.
[0044] c) After releasing the vacuum, add 0.5 parts of bis(2-morpholinodiethyl) ether and 10 parts of compound antibacterial agent, then heat to 90℃ and stir rapidly for 10 min under vacuum conditions <100Pa.
[0045] d) The product is obtained by rapid discharge and packaging under nitrogen protection, and the prepared product sample is marked as A2.
[0046] Example 3
[0047] The specific preparation steps of an antibacterial and UV-resistant polyurethane coating are as follows:
[0048] (1) Preparation of monolayer MXene: 1.56 g LiF and 20 mL of 9 mol / L HCl solution were added to a polytetrafluoroethylene reactor and reacted at 40 °C for 15 min. Then, 1 g Ti3AlC2 was slowly added to the reactor in small amounts several times and reacted at 40 °C and 500 rpm for 48 h. The resulting slurry was centrifuged and washed until pH=6. The precipitate was then separated by vacuum filtration. The precipitate was then centrifuged and washed again until a viscous precipitate appeared and the upper liquid turned black. The viscous precipitate was poured into a three-necked round-bottom flask, 50 mL of deionized water was added, the flask was filled with nitrogen and sealed, and the flask was placed in an ultrasonic machine at 5 °C for 1.5 h. After the ultrasonic treatment, the flask was centrifuged at 2500 rpm for 30 min to obtain a dark green dispersion. The precipitate was separated by vacuum filtration and dried at 40 °C for 2 h. The precipitate was then ground into powder to obtain monolayer MXene, which was then placed in a desiccator and sealed for storage.
[0049] (2) Preparation of composite antibacterial agent: Take 16 mg of the above monolayer MXene, disperse it in 100 mL of deionized water, stir at 30 °C for 30 min to make it evenly dispersed, then add 100 mL of zinc acetate solution with a concentration of 0.06 mol / L, continue stirring for 30 min, then add 100 mL of phytic acid solution with a concentration of 0.1 mol / L at a rate of 2 drops / second, continue stirring for 6 h, then add 100 mL of chitosan dispersion with a concentration of 20 g / L, heat to 40 °C and stir for 24 h, then filter, wash and dry for later use.
[0050] (3) Preparation of polyurethane coatings:
[0051] a) By weight, add 37 parts of polycaprolactone diol, 15 parts of polysorbate ricinoleate diol, 22 parts of polytetrahydrofuran diol and 0.05 parts of antioxidant 1010 into a three-necked flask and stir until homogeneous. Heat to 120°C and dehydrate for 2 hours under a vacuum of <100Pa.
[0052] b) Cool down to 70°C, add 14 parts of MDI, and stir the reaction for 1 hour at 70°C and a vacuum degree <100Pa.
[0053] c) After releasing the vacuum, add 0.5 parts of bis(2-morpholinodiethyl) ether and 15 parts of compound antibacterial agent, then heat to 90°C and stir rapidly for 10 minutes under a vacuum of <100Pa.
[0054] d) The product is obtained by rapid discharge and packaging under nitrogen protection, and the prepared product sample is marked as A3.
[0055] Example 4
[0056] The specific preparation steps of an antibacterial and UV-resistant polyurethane coating are as follows:
[0057] (1) Preparation of monolayer MXene: 1.56 g LiF and 20 mL of 9 mol / L HCl solution were added to a polytetrafluoroethylene reactor and reacted at 40 °C for 15 min. Then, 1 g Ti3AlC2 was slowly added to the reactor in small amounts several times and reacted at 40 °C and 500 rpm for 48 h. The resulting slurry was centrifuged and washed until pH=6. The precipitate was then separated by vacuum filtration. The precipitate was then centrifuged and washed again until a viscous precipitate appeared and the upper liquid turned black. The viscous precipitate was poured into a three-necked round-bottom flask, 50 mL of deionized water was added, the flask was filled with nitrogen and sealed, and the flask was placed in an ultrasonic machine at 5 °C for 1.5 h. After the ultrasonic treatment, the flask was centrifuged at 2500 rpm for 30 min to obtain a dark green dispersion. The precipitate was separated by vacuum filtration and dried at 40 °C for 2 h. The precipitate was then ground into powder to obtain monolayer MXene, which was then placed in a desiccator and sealed for storage.
[0058] (2) Preparation of composite antibacterial agent: Take 16 mg of the above monolayer MXene, disperse it in 100 mL of deionized water, stir at 30 °C for 30 min to make it evenly dispersed, then add 100 mL of zinc acetate solution with a concentration of 0.06 mol / L, continue stirring for 30 min, then add 100 mL of phytic acid solution with a concentration of 0.1 mol / L at a rate of 2 drops / second, continue stirring for 6 h, then add 100 mL of chitosan dispersion with a concentration of 20 g / L, heat to 40 °C and stir for 24 h, then filter, wash and dry for later use.
[0059] (3) Preparation of polyurethane coatings:
[0060] a) By weight, add 37 parts of polycaprolactone diol, 15 parts of polysorbate ricinoleate diol, 22 parts of polytetrahydrofuran diol and 0.05 parts of antioxidant 1010 into a three-necked flask and stir until homogeneous. Heat to 120°C and dehydrate for 2 hours under a vacuum of <100Pa.
[0061] b) Cool down to 70°C, add 14 parts of MDI, and stir the reaction for 1 hour at 70°C and a vacuum degree <100Pa.
[0062] c) After releasing the vacuum, add 0.5 parts of bis(2-morpholinodiethyl) ether and 20 parts of compound antibacterial agent, then heat to 90℃ and stir rapidly for 10 min under vacuum conditions <100Pa.
[0063] d) The product is obtained by rapid discharge and packaging under nitrogen protection, and the prepared product sample is marked as A4.
[0064] Comparative Example 1
[0065] The specific preparation steps of an antibacterial and UV-resistant polyurethane coating are as follows:
[0066] (1) Preparation of MXene-free composite antibacterial agent: 100 mL of 0.06 mol / L zinc acetate solution was placed in a three-necked flask equipped with a reflux condenser, and then 100 mL of 0.1 mol / L phytic acid solution was added dropwise at a rate of 2 drops / second. After stirring for 6 hours, 100 mL of 20 g / L chitosan dispersion was added, and the mixture was heated to 40 °C and stirred for 24 hours. After filtration, washing, drying and storage were then carried out for later use.
[0067] (2) Preparation of polyurethane coatings:
[0068] a) By weight, add 37 parts of polycaprolactone diol, 15 parts of polysorbate ricinoleate diol, 22 parts of polytetrahydrofuran diol and 0.05 parts of antioxidant 1010 into a three-necked flask and stir until homogeneous. Heat to 120°C and dehydrate for 2 hours under a vacuum of <100Pa.
[0069] b) Cool down to 70°C, add 14 parts of MDI, and stir the reaction for 1 hour at 70°C and a vacuum degree <100Pa.
[0070] c) After releasing the vacuum, add 0.5 parts of bis(2-morpholinodiethyl) ether and 10 parts of MXene-free composite antibacterial agent, then heat to 90°C and stir rapidly for 10 minutes under a vacuum of <100Pa.
[0071] d) The product sample is prepared by rapid discharge and encapsulation under nitrogen protection and labeled as B1.
[0072] Comparative Example 2
[0073] The specific preparation steps of an antibacterial and UV-resistant polyurethane coating are as follows:
[0074] (1) Preparation of monolayer MXene: 1.56 g LiF and 20 mL of 9 mol / L HCl solution were added to a polytetrafluoroethylene reactor and reacted at 40 °C for 15 min. Then, 1 g Ti3AlC2 was slowly added to the reactor in small amounts several times and reacted at 40 °C and 500 rpm for 48 h. The resulting slurry was centrifuged and washed until pH=6. The precipitate was then separated by vacuum filtration. The precipitate was then centrifuged and washed again until a viscous precipitate appeared and the upper liquid turned black. The viscous precipitate was poured into a three-necked round-bottom flask, 50 mL of deionized water was added, the flask was filled with nitrogen and sealed, and the flask was placed in an ultrasonic machine at 5 °C for 1.5 h. After the ultrasonic treatment, the flask was centrifuged at 2500 rpm for 30 min to obtain a dark green dispersion. The precipitate was separated by vacuum filtration and dried at 40 °C for 2 h. The precipitate was then ground into powder to obtain monolayer MXene, which was then placed in a desiccator and sealed for storage.
[0075] (2) Preparation of Zn-free composite antibacterial agent: Take 16 mg of the above monolayer MXene, disperse it in 100 mL of deionized water, stir at 30 °C for 30 min to make it evenly dispersed, then add 100 mL of 0.1 mol / L phytic acid solution at a rate of 2 drops / second, continue stirring for 6 h, then add 100 mL of 20 g / L chitosan dispersion, heat to 40 °C and stir for 24 h, then filter, wash and dry for later use.
[0076] (3) Preparation of polyurethane coatings:
[0077] a) By weight, add 37 parts of polycaprolactone diol, 15 parts of polysorbate ricinoleate diol, 22 parts of polytetrahydrofuran diol and 0.05 parts of antioxidant 1010 into a three-necked flask and stir until homogeneous. Heat to 120°C and dehydrate for 2 hours under a vacuum of <100Pa.
[0078] b) Cool down to 70°C, add 14 parts of MDI, and stir the reaction for 1 hour at 70°C and a vacuum degree <100Pa.
[0079] c) After releasing the vacuum, add 0.5 parts of bis(2-morpholinodiethyl) ether and 10 parts of a Zn-free composite antibacterial agent, then heat to 90°C and stir rapidly for 10 minutes under a vacuum of <100Pa.
[0080] d) The product sample is prepared by rapid discharge and encapsulation under nitrogen protection and labeled as B2.
[0081] Comparative Example 3
[0082] The specific preparation steps of an antibacterial and UV-resistant polyurethane coating are as follows:
[0083] (1) Preparation of monolayer MXene: 1.56 g LiF and 20 mL of 9 mol / L HCl solution were added to a polytetrafluoroethylene reactor and reacted at 40 °C for 15 min. Then, 1 g Ti3AlC2 was slowly added to the reactor in small amounts several times and reacted at 40 °C and 500 rpm for 48 h. The resulting slurry was centrifuged and washed until pH=6. The precipitate was then separated by vacuum filtration. The precipitate was then centrifuged and washed again until a viscous precipitate appeared and the upper liquid turned black. The viscous precipitate was poured into a three-necked round-bottom flask, 50 mL of deionized water was added, the flask was filled with nitrogen and sealed, and the flask was placed in an ultrasonic machine at 5 °C for 1.5 h. After the ultrasonic treatment, the flask was centrifuged at 2500 rpm for 30 min to obtain a dark green dispersion. The precipitate was separated by vacuum filtration and dried at 40 °C for 2 h. The precipitate was then ground into powder to obtain monolayer MXene, which was then placed in a desiccator and sealed for storage.
[0084] (2) Preparation of chitosan-free composite antibacterial agent: Take 16 mg of the above monolayer MXene, disperse it in 100 mL of deionized water, stir at 30 °C for 30 min to make it evenly dispersed, then add 100 mL of 0.06 mol / L zinc acetate solution, continue stirring for 30 min, then add 100 mL of 0.1 mol / L phytic acid solution at a rate of 2 drops / second, continue stirring for 6 h, then add an appropriate amount of 1 mol / L sodium hydroxide solution to adjust the pH to 7, raise the temperature to 40 °C and stir for 24 h, then filter, wash and dry for later use.
[0085] (3) Preparation of polyurethane coatings:
[0086] a) By weight, add 37 parts of polycaprolactone diol, 15 parts of polysorbate ricinoleate diol, 22 parts of polytetrahydrofuran diol and 0.05 parts of antioxidant 1010 into a three-necked flask and stir until homogeneous. Heat to 120°C and dehydrate for 2 hours under a vacuum of <100Pa.
[0087] b) Cool down to 70°C, add 14 parts of MDI, and stir the reaction for 1 hour at 70°C and a vacuum degree <100Pa.
[0088] c) After releasing the vacuum, add 0.5 parts of bis(2-morpholinodiethyl) ether and 10 parts of chitosan-free composite antibacterial agent, then heat to 90°C and stir rapidly for 10 minutes under a vacuum of <100Pa.
[0089] d) The product is obtained by rapid discharge and packaging under nitrogen protection, and the prepared product sample is marked as B3.
[0090] Comparative Example 4
[0091] The specific preparation steps of an antibacterial and UV-resistant polyurethane coating are as follows:
[0092] (1) Preparation of monolayer MXene: 1.56 g LiF and 20 mL of 9 mol / L HCl solution were added to a polytetrafluoroethylene reactor and reacted at 40 °C for 15 min. Then, 1 g Ti3AlC2 was slowly added to the reactor in small amounts several times and reacted at 40 °C and 500 rpm for 48 h. The resulting slurry was centrifuged and washed until pH=6. The precipitate was then separated by vacuum filtration. The precipitate was then centrifuged and washed again until a viscous precipitate appeared and the upper liquid turned black. The viscous precipitate was poured into a three-necked round-bottom flask, 50 mL of deionized water was added, the flask was filled with nitrogen and sealed, and the flask was placed in an ultrasonic machine at 5 °C for 1.5 h. After the ultrasonic treatment, the flask was centrifuged at 2500 rpm for 30 min to obtain a dark green dispersion. The precipitate was separated by vacuum filtration and dried at 40 °C for 2 h. The precipitate was then ground into powder to obtain monolayer MXene, which was then placed in a desiccator and sealed for storage.
[0093] (2) Preparation of phytic acid-free composite antibacterial agent: Take 16 mg of the above monolayer MXene, disperse it in 100 mL of deionized water, stir at 30 °C for 30 min to make it evenly dispersed, then add 100 mL of 0.06 mol / L zinc acetate solution, continue stirring for 30 min, then add 100 mL of 20 g / L chitosan dispersion, heat to 40 °C and stir for 24 h, then filter, wash and dry for later use.
[0094] (3) Preparation of polyurethane coatings:
[0095] a) By weight, add 37 parts of polycaprolactone diol, 15 parts of polysorbate ricinoleate diol, 22 parts of polytetrahydrofuran diol and 0.05 parts of antioxidant 1010 into a three-necked flask and stir until homogeneous. Heat to 120°C and dehydrate for 2 hours under a vacuum of <100Pa.
[0096] b) Cool down to 70°C, add 14 parts of MDI, and stir the reaction for 1 hour at 70°C and a vacuum degree <100Pa.
[0097] c) After releasing the vacuum, add 0.5 parts of bis(2-morpholinodiethyl) ether and 10 parts of phytic acid-free composite antibacterial agent, then heat to 90°C and stir rapidly for 10 minutes under a vacuum of <100Pa.
[0098] d) The product is obtained by rapid discharge and packaging under nitrogen protection, and the prepared product sample is marked as B4.
[0099] Comparative Example 5
[0100] The specific preparation steps of a polyurethane coating are as follows:
[0101] a) By weight, add 37 parts of polycaprolactone diol, 15 parts of polysorbate ricinoleate diol, 22 parts of polytetrahydrofuran diol and 0.05 parts of antioxidant 1010 into a three-necked flask and stir until homogeneous. Heat to 120°C and dehydrate for 2 hours under a vacuum of <100Pa.
[0102] b) Cool down to 70°C, add 14 parts of MDI, and stir the reaction for 1 hour at 70°C and a vacuum degree <100Pa.
[0103] c) After releasing the vacuum, add 0.5 parts of bis(2-morpholinodiethyl) ether, then heat to 90°C and stir rapidly for 10 min under a vacuum of <100 Pa.
[0104] d) The product is obtained by rapid discharge and packaging under nitrogen protection, and the prepared product sample is marked as B5.
[0105] Comparative Example 6
[0106] (1) Preparation of monolayer MXene: 1.56 g LiF and 20 mL of 9 mol / L HCl solution were added to a polytetrafluoroethylene reactor and reacted at 40 °C for 15 min. Then, 1 g Ti3AlC2 was slowly added to the reactor in small amounts several times and reacted at 40 °C and 500 rpm for 48 h. The resulting slurry was centrifuged and washed until pH=6. The precipitate was then separated by vacuum filtration. The precipitate was then centrifuged and washed again until a viscous precipitate appeared and the upper liquid turned black. The viscous precipitate was poured into a three-necked round-bottom flask, 50 mL of deionized water was added, the flask was filled with nitrogen and sealed, and the flask was placed in an ultrasonic machine at 5 °C for 1.5 h. After the ultrasonic treatment, the flask was centrifuged at 2500 rpm for 30 min to obtain a dark green dispersion. The precipitate was separated by vacuum filtration and dried at 40 °C for 2 h. The precipitate was then ground into powder to obtain monolayer MXene, which was then placed in a desiccator and sealed for storage.
[0107] (2) Preparation of polyurethane coatings:
[0108] a) By weight, add 37 parts of polycaprolactone diol, 15 parts of polysorbate ricinoleate diol, 22 parts of polytetrahydrofuran diol and 0.05 parts of antioxidant 1010 into a three-necked flask and stir until homogeneous. Heat to 120°C and dehydrate for 2 hours under a vacuum of <100Pa.
[0109] b) Cool down to 70°C, add 14 parts of MDI, and stir the reaction for 1 hour at 70°C and a vacuum degree <100Pa.
[0110] c) After releasing the vacuum, add 0.5 parts of bis(2-morpholinodiethyl) ether, 0.014 parts of MXene, 0.673 parts of zinc acetate, 1.815 parts of chitosan, and 5.998 parts of phytic acid. Then heat to 90°C and stir rapidly for 10 minutes under a vacuum of <100Pa.
[0111] d) The product is obtained by rapid discharge and packaging under nitrogen protection, and the prepared product sample is marked as A6.
[0112] test:
[0113] The polyurethane coatings obtained in Examples 1-4 and Comparative Examples 1-6 were tested for elongation at break and tensile strength after 72 hours of film formation according to GB / T1040.3-2006. Their film properties after 72 hours of UV irradiation were also measured to characterize their UV aging resistance. Comparative Example 5 was used as a blank control, and the antibacterial effect of the obtained film layer was tested at 12 hours and 168 hours. The results are shown in Table 1.
[0114] Table 1. Comparison of performance of different polyurethane coatings after film formation
[0115]
[0116] As shown in Table 1, a comparison between A1-A4 and B5 reveals that polyurethane coatings prepared with different proportions of composite antibacterial agents exhibit good antibacterial effects, with the antibacterial effect becoming more significant as the proportion of the composite antibacterial agent increases. Simultaneously, the coatings' resistance to ultraviolet aging is also improved. Taking A2, which has better overall performance, as an example, after 72 hours of ultraviolet irradiation, its elongation at break increased from 199.88% to 214.39%, and its tensile strength increased from 1.88 MPa to 2.24 MPa. Compared to the blank control group, its antibacterial rate reached 99.14% after 12 hours, and it maintained a good antibacterial effect even after 168 hours.
[0117] The comparison between A2 and B1 shows that when the composite antibacterial agent does not contain MXene, its antibacterial and anti-UV effects are relatively poor. This is because MXene's high specific surface area and abundant surface functional groups can not only graft phytic acid onto the MXene surface, making it evenly distributed, effectively alleviating the uneven dispersion of phytic acid in the polyurethane matrix, but also bind with hydrogen bonds between lipopolysaccharides on the cell membrane, hindering the intake of bacterial nutrients and thus inhibiting bacterial growth.
[0118] The comparison between A2 and B2 shows that the introduction of Zn ions into the composite antibacterial agent has a significant effect on improving the coating's resistance to ultraviolet aging and antibacterial properties. This is because the nano zinc oxide formed by the oxidation of Zn after release has a strong absorption and scattering ability for ultraviolet light. Moreover, under ultraviolet irradiation, nano zinc oxide will convert the water or hydroxyl groups adsorbed on the surface into hydroxyl radicals, and the adsorbed oxygen into reactive oxygen species, which can react with most organic matter to kill most bacteria and viruses.
[0119] The comparison between A2 and B3 shows that chitosan in the composite antibacterial agent has a significant effect on improving the antibacterial effect and extending the antibacterial and anti-aging effects. This is because the amino groups on the chitosan molecular chain can interact with metal ions that play a key role in the growth of microorganisms, effectively inhibiting the growth of microorganisms. In addition to improving the antibacterial effect of the coating, it can also react with excess isocyanate groups in the coating, enhance the compatibility with the matrix, and reduce the loss of mechanical properties after the coating film is formed.
[0120] Phytic acid's chelating effect can capture more Zn ions and also provide active sites for chitosan ion exchange. A comparison of A2 and B4 shows that in the absence of phytic acid, the binding effect of chitosan with the antibacterial system decreases, which significantly reduces the mechanical properties of the coating, and also reduces the antibacterial effect and duration to varying degrees.
[0121] The comparison between A2 and B6 shows that directly adding the composite antibacterial agent components to the polyurethane coating in a certain proportion results in a significant decrease in the mechanical properties of the polyurethane coating film due to the extremely poor compatibility between phytic acid, zinc acetate and the polyurethane matrix.
[0122] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.
Claims
1. An antibacterial and UV-resistant polyurethane coating, characterized in that, By weight, the raw materials used include: 30-45 parts of polycaprolactone diol, 10-20 parts of polysorbate adipate diol, 18-25 parts of polytetrahydrofuran diol, 5-25 parts of composite antibacterial agent, 0.05-0.1 parts of antioxidant, 10-20 parts of MDI, and 0.5-1 parts of catalyst; The preparation of the composite antibacterial agent includes the following steps: (1) Preparation of monolayer MXene: 1.56g LiF and 20mL HCl solution with a concentration of 9mol / L were mixed and reacted at 40℃ for 15min. Then, 1g Ti3AlC2 was slowly added in small amounts several times. The mixture was stirred at 40-45℃ and 500rpm for 48h. The resulting slurry was centrifuged and washed until pH=6. The precipitate was separated by filtration. The precipitate was centrifuged and washed until a viscous precipitate appeared and the upper liquid turned black. The viscous precipitate was taken, deionized water was added and nitrogen was filled and sealed. The mixture was then sonicated at 5℃ for 1.5h. After the process, it was centrifuged to obtain a dark green dispersion. The precipitate obtained after filtration was vacuum dried at 40℃ for 2h. After drying, it was ground into powder to obtain monolayer MXene. The powder was dried and sealed for storage. (2) Preparation of composite antibacterial agent: 16 mg of monolayer MXene was placed in 100 mL of deionized water and stirred at 30 °C for 30 min to disperse it evenly. Then, 100 mL of zinc acetate solution with a concentration of 0.06 mol / L was added and stirred for another 30 min. Then, 100 mL of phytic acid solution with a concentration of 0.1 mol / L was added dropwise at a rate of 2 drops / second and stirred for another 6 h. Then, 100 mL of chitosan dispersion with a concentration of 20 g / L was added. The mixture was heated to 40 °C and stirred for 24 h. After filtration, washing and drying, the product was obtained.
2. The antibacterial and UV-resistant polyurethane coating according to claim 1, characterized in that: The number-average molecular weight of the polycaprolactone diol is 200-5000.
3. The antibacterial and UV-resistant polyurethane coating according to claim 1, characterized in that: The number-average molecular weight of the poly(ricinoleic adipate) diol is 500-3000.
4. The antibacterial and UV-resistant polyurethane coating according to claim 1, characterized in that: The number-average molecular weight of the polytetrahydrofuran diol is 500-3000.
5. The antibacterial and UV-resistant polyurethane coating according to claim 1, characterized in that: The catalyst is one of bis(2-morpholinodiethyl) ether, dibutyltin dilaurate, and tin isooctanoate.
6. The antibacterial and UV-resistant polyurethane coating according to claim 1, characterized in that, The preparation steps of the polyurethane coating are as follows: a) Add polycaprolactone diol, polysorbate ricinoleate diol, polytetrahydrofuran diol and antioxidant to a three-necked flask and stir until homogeneous. Heat to 120℃-130℃ and dehydrate for 2 hours under vacuum <100Pa. b) Cool down to 70℃-80℃, add MDI, and stir the reaction for 1-2 hours at 70℃-80℃ and vacuum degree <100Pa. c) After releasing the vacuum, add the catalyst and composite antibacterial agent, then heat to 90°C and stir rapidly for 10 minutes under a vacuum of <100Pa. d) The material is rapidly discharged and packaged under nitrogen protection.