Weather-resistant antibacterial polyurethane coating and preparation method thereof

Abstract

The application provides a weather-resistant antibacterial polyurethane coating, raw materials of the polyurethane coating including polyether triols, isophorone diisocyanate, hydroxyethyl methacrylate and nano-silver loaded aliphatic amine modified graphene oxide. The application also provides a preparation method of the weather-resistant antibacterial polyurethane coating. The weather-resistant antibacterial polyurethane coating obtained by the application has good mechanical properties, strong antibacterial property, strong water resistance and strong acid resistance, good high and low temperature aging performance, long service life and wide application scenarios.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a weather-resistant antibacterial polyurethane coating and its preparation method. Background Technology

[0002] Compared to their solvent-based counterparts, polyurethane (PU) emulsions and polyacrylic acid (PAA) emulsions offer advantages such as low cost, safety, non-flammability, non-toxicity, and environmental friendliness. However, pure PAA emulsions suffer from poor abrasion resistance, water resistance, and chemical resistance, and also have high solids content, limiting their application range. Current technology has revealed a complementary relationship between PU and PAA properties. Combining them to form a polyurethane acrylate (PUA) composite emulsion combines the advantages of both, exhibiting good abrasion resistance, corrosion resistance, gloss, and softness and elasticity. This combination is hailed as "third-generation waterborne polyurethane" and represents a current trend in coatings. However, with societal and technological advancements, the application scenarios and environments for coatings are becoming increasingly complex and diverse. Therefore, conventional PUA can no longer meet these demands.

[0003] Graphene possesses excellent comprehensive properties, such as high electrical conductivity, good thermal conductivity, and high strength; nano-silver exhibits strong inhibitory and bactericidal effects against dozens of pathogenic microorganisms, demonstrating excellent antibacterial and deodorizing properties. Graphene, nano-silver, and other materials have been widely used in polymer materials to improve their corrosion resistance, heat resistance, electrical and thermal conductivity, mechanical properties, and antibacterial and deodorizing properties. However, the difficulty in dispersing graphene and nano-silver in polymer systems, leading to aggregation and sedimentation, limits their application. This patent modifies graphene and nano-silver materials to improve their dispersibility in polyurethane materials, resulting in a novel polyurethane coating material. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a weather-resistant antibacterial polyurethane coating and its preparation method. The weather-resistant antibacterial polyurethane coating uses graphene and nano-silver materials, and can have a graphene and nano-silver material system with good dispersibility, thereby achieving the weather resistance and antibacterial effect of the polyurethane coating.

[0005] To achieve the above objectives, the present invention provides a weather-resistant and antibacterial polyurethane coating, wherein the raw materials of the polyurethane coating include polyether triol, isophorone diisocyanate, hydroxyethyl methacrylate, and nano-silver-supported aliphatic amine-modified graphene oxide.

[0006] The aforementioned nano-silver-supported fatty amine-modified graphene oxide is a special functional additive.

[0007] In the above-mentioned weather-resistant and antibacterial polyurethane coating, preferably, the raw materials of the polyurethane coating also include N-methylpyrrolidone, dibutyltin dilaurate and dimethylolpropionic acid.

[0008] In the above-mentioned weather-resistant and antibacterial polyurethane coating, preferably, the molar ratio of the polyether triol to the isophorone diisocyanate can be 2:1 to 1:1.

[0009] In the above-mentioned weather-resistant and antibacterial polyurethane coating, preferably, the amount of nano-silver-supported fatty amine-modified graphene oxide can be 10%-50% of the mass of the polyether triol.

[0010] In the aforementioned weather-resistant and antibacterial polyurethane coating, preferably, the nano-silver-supported aliphatic amine-modified graphene oxide is prepared by the following method:

[0011] Graphene oxide powder was dispersed in deionized water to obtain an aqueous dispersion of graphene oxide.

[0012] A fatty amine is dissolved in an ethanol solution to obtain a fatty amine ethanol solution;

[0013] Aqueous dispersion of graphene oxide and ethanol solution of fatty amine were mixed and reacted. After the reaction was completed, the residue was filtered and dried to obtain fatty amine modified graphene oxide.

[0014] Aliphatic amine-modified graphene oxide was dispersed in a 75-95% ethanol solution, then silver nitrate solution was added, mixed well, and then sodium hydroxide solution was added dropwise. After the addition was completed, the reaction was carried out at 150-180℃ for 20-26 hours. After the reaction was completed, the product was filtered and dried to obtain nano-silver-supported aliphatic amine-modified graphene oxide.

[0015] In the above-mentioned weather-resistant and antibacterial polyurethane coating, in the step of dispersing graphene oxide powder in deionized water, the amount of deionized water can be adjusted as needed to form a suspension. Preferably, the amount of deionized water is 2-10 times the volume of graphene oxide.

[0016] In the above-mentioned weather-resistant and antibacterial polyurethane coating, preferably, in the step of dissolving the fatty amine in an ethanol solution to obtain a fatty amine ethanol solution, the concentration of the ethanol solution is 75%-95%; and the mass-volume ratio of the fatty amine to the ethanol solution is 1:(50-200).

[0017] In the above-mentioned weather-resistant and antibacterial polyurethane coating, preferably, in the step of dispersing aliphatic amine-modified graphene oxide in an ethanol solution with a concentration of 75-95%, the amount of ethanol solution can be adjusted as needed; the standard is to completely disperse the aliphatic amine-modified graphene oxide; preferably, the mass-volume ratio of aliphatic amine-modified graphene oxide to ethanol solution is 1:(100-1000).

[0018] In the above-mentioned weather-resistant and antibacterial polyurethane coating, preferably, in the step of dispersing aliphatic amine-modified graphene oxide in a 75-95% ethanol solution, then adding silver nitrate solution, mixing well, and then adding sodium hydroxide solution dropwise, the concentration of silver nitrate solution can be 0.001-0.005 g / mL; preferably, the concentration of sodium hydroxide can be 0.001-0.005 g / mL; preferably, on a dry weight basis, the mass ratio of the sodium hydroxide solution to the aliphatic amine-modified graphene oxide is 1:(5-10).

[0019] In the above-mentioned weather-resistant and antibacterial polyurethane coating, preferably, the mass ratio of the graphene oxide powder to the fatty amine can be 1:2 to 2:1;

[0020] On a dry weight basis, the mass ratio of the silver nitrate solution to the fatty amine-modified graphene oxide is 1:5 to 1:10.

[0021] In the above-mentioned weather-resistant and antibacterial polyurethane coatings, preferably, the fatty amine is a C8-C18 fatty amine.

[0022] In the above-mentioned weather-resistant and antibacterial polyurethane coating, the fatty amine is further preferably a C8-C12 fatty amine.

[0023] In this invention, after the graphene oxide is modified with aliphatic amines, the number of oxygen-containing groups on the graphene surface is greatly reduced, and a certain amount of long-chain alkanes are grafted on, which promotes its dispersion in polyurethane.

[0024] In the above-mentioned weather-resistant and antibacterial polyurethane coating, preferably, in the step of mixing and reacting the graphene oxide aqueous dispersion and the fatty amine ethanol solution, and filtering and taking the filter residue after the reaction is completed, the reaction temperature is 80-100℃ and the reaction time is 18-24h.

[0025] The present invention also provides a method for preparing the above-mentioned weather-resistant and antibacterial polyurethane coating, comprising the following steps:

[0026] Polyether triol and N-methylpyrrolidone were mixed at 50-60℃, and then a mixture of dibutyltin dilaurate and isophorone diisocyanate was added dropwise. The mixture was heated for 1.5-3 hours and then cooled to below 50℃. Dimethylolpropionic acid was then added to continue the reaction. After the reaction was completed, hydroxyethyl methacrylate was added to continue the reaction to obtain the liquid product of the first reaction.

[0027] Deionized water was added dropwise to the first reaction product liquid for dispersion reaction, and then nano-silver-supported fatty amine-modified graphene oxide was added. The temperature was raised to 40-50℃ and the reaction was carried out for 2-4 hours to obtain weather-resistant antibacterial polyurethane coating.

[0028] In the above preparation method, preferably, the molar ratio of the polyether triol to the N-methylpyrrolidone is 2:1 to 1:2.

[0029] In the above preparation method, preferably, the molar ratio of dimethylolpropionic acid to polyether triol is 2:1 to 1:2.

[0030] In the above preparation method, preferably, in the step of adding deionized water dropwise to the first reaction product liquid for dispersion reaction, the amount of deionized water is such that it can completely disperse the first reaction product liquid; more preferably, the amount of deionized water is 10-20 times the weight of the nano-silver-supported aliphatic amine-modified graphene oxide.

[0031] In the above preparation method, preferably, the reaction temperature for the continued reaction is 55-65℃, and the reaction time is 1-5h;

[0032] The dispersion reaction is carried out at a temperature of 30-40℃ for 0.5-1h.

[0033] The reaction temperature of the heating reaction is 75-85℃.

[0034] In the above preparation method, preferably, the mass of the dibutyltin dilaurate is 0.2-0.5% of the mass of the polyether triol.

[0035] As can be seen from the above, the technical solution provided by the present invention has the following significant beneficial effects:

[0036] The weather-resistant and antibacterial polyurethane coating of this invention uses nano-silver-supported aliphatic amine-modified graphene oxide as a special functional additive. This effectively integrates unstable materials such as graphene and nano-silver into the polyurethane coating system, significantly improving the weather resistance, antibacterial properties, and mechanical properties of the polyurethane coating. The weather-resistant and antibacterial polyurethane coating obtained by this invention exhibits good mechanical properties, strong antibacterial activity, strong water and acid resistance, good high and low temperature aging performance, long service life, and wide range of applications. Detailed Implementation

[0037] To provide a clearer understanding of the technical features, objectives, and beneficial effects of this invention, the technical solution of this invention is described in detail below, but this should not be construed as limiting the scope of implementation of this invention. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; the reagents and materials described, unless otherwise specified, are commercially available.

[0038] In the following examples, the polyether triol was from Jiangsu Haian Petrochemical Plant; dibutyltin dilaurate was from Wuhan Kanos Technology Co., Ltd.; isophorone diisocyanate (IPDI) was from Bayer AG; dodecylamine (DDA) was from Shanghai Maclean Biochemical Technology Co., Ltd.; sodium hydroxide (NaOH) and silver nitrate (AgNO3) were from Tianjin Damao Chemical Reagent Factory; and graphene oxide (GO) was prepared in the laboratory.

[0039] Example 1

[0040] This embodiment provides a weather-resistant and antibacterial polyurethane coating. The raw materials of the polyurethane coating include polyether triol, isophorone diisocyanate, hydroxyethyl methacrylate, and nano-silver-supported aliphatic amine-modified graphene oxide.

[0041] The nano-silver-supported aliphatic amine-modified graphene oxide in this embodiment was prepared as follows:

[0042] 0.6 g of graphene oxide powder was dispersed in 10 mL of deionized water and ultrasonically dispersed for 30 min to obtain an aqueous dispersion of graphene oxide, which was then poured into a three-necked flask.

[0043] Dissolve 0.9g of dodecylamine in 90mL of ethanol solution (concentration 75-80%) to obtain a fatty amine ethanol solution, and pour it into a three-necked flask;

[0044] The aqueous dispersion of graphene oxide was mixed with an ethanol solution of a fatty amine and refluxed at 90°C for 20 h. After the reaction was completed, the product was filtered and washed 3-4 times with anhydrous ethanol. Finally, it was vacuum dried at 60°C for 6-12 h to obtain aliphatic amine modified graphene oxide.

[0045] 0.1 g of aliphatic amine-modified graphene oxide was dispersed in 50 mL of an ethanol solution with an alcohol-to-water ratio of 4:1 and ultrasonically dispersed for 30 min. Then, 10 mL of silver nitrate solution with a concentration of 0.002 g / mL was added, and the mixture was placed in a hydrothermal reactor. 5 mL of sodium hydroxide solution with a concentration of 0.002 g / mL was then added dropwise. After the addition was complete, the hydrothermal reactor was placed in an oven at 160 °C for 24 h. After the reaction was completed, the product was filtered and separated, washed 3-4 times with ethanol, and dried in a vacuum chamber at 60 °C for 6-12 h to obtain nano-silver-supported aliphatic amine-modified graphene oxide.

[0046] The weather-resistant and antibacterial polyurethane coating in this embodiment is prepared as follows:

[0047] Under the condition of 50-60℃ in the reactor, 10g of polyether triol and 10g of N-methylpyrrolidone were added to the reactor and stirred. Then, a mixture of 0.025g of dibutyltin dilaurate and 5.6g of isophorone diisocyanate was added dropwise to the reactor. The temperature was raised to 80℃ and reacted for 2-2.5h. After that, the temperature was lowered to below 50℃, and 10g of dimethylolpropionic acid was added. The reaction was continued at 60℃ for 2-3h. After the reaction was completed, 3.25g of hydroxyethyl methacrylate was added, and the reaction was continued at 60℃ for 4h. After the reaction was completed, the first reaction product liquid was obtained. The first reaction product liquid system was cooled to below 35℃, and 60g of deionized water was added dropwise for dispersion reaction. The reaction was carried out for 0.5h. Then, 5g of nano-silver supported aliphatic amine modified graphene oxide was added, and the temperature was raised to 40-50℃. The reaction was carried out for 2-4h to obtain the final product, weather-resistant antibacterial polyurethane coating.

[0048] Example 2

[0049] This embodiment provides a weather-resistant and antibacterial polyurethane coating. The raw materials of the polyurethane coating include polyether triol, isophorone diisocyanate, hydroxyethyl methacrylate, and nano-silver-supported aliphatic amine-modified graphene oxide.

[0050] The nano-silver-supported aliphatic amine-modified graphene oxide in this embodiment was prepared as follows:

[0051] 0.6 g of graphene oxide powder was dispersed in 10 mL of deionized water and ultrasonically dispersed for 30 min to obtain an aqueous dispersion of graphene oxide, which was then poured into a three-necked flask.

[0052] Dissolve 0.9g of dodecylamine in 90mL of 80% ethanol solution to obtain a fatty amine ethanol solution, and pour it into a three-necked flask;

[0053] The aqueous dispersion of graphene oxide was mixed with an ethanol solution of a fatty amine and refluxed at 90°C for 20 h. After the reaction was completed, the product was filtered and washed 3-4 times with anhydrous ethanol. Finally, it was vacuum dried at 60°C for 6-12 h to obtain aliphatic amine modified graphene oxide.

[0054] 0.1 g of aliphatic amine-modified graphene oxide was dispersed in 50 mL of an ethanol solution with an alcohol-to-water ratio of 4:1 and ultrasonically dispersed for 30 min. Then, 10 mL of silver nitrate solution with a concentration of 0.001 g / mL was added, and the mixture was placed in a hydrothermal reactor. 5 mL of sodium hydroxide solution with a concentration of 0.002 g / mL was then added dropwise. After the addition was complete, the hydrothermal reactor was placed in an oven at 160 °C for 24 h. After the reaction was completed, the product was filtered and separated, washed 3-4 times with ethanol, and dried in a vacuum chamber at 60 °C for 6-12 h to obtain nano-silver-supported aliphatic amine-modified graphene oxide.

[0055] The weather-resistant and antibacterial polyurethane coating in this embodiment is prepared as follows:

[0056] Under conditions of 50-60℃ in the reactor, 10g of polyether triol and 10g of N-methylpyrrolidone were added and stirred. A mixture of 0.025g of dibutyltin dilaurate and 5.6g of isophorone diisocyanate was added dropwise to the reactor. The temperature was raised to 80℃ and reacted for 2-2.5h. The temperature was then lowered to below 50℃, and 10g of dimethylolpropionic acid was added. The reaction was continued at 60℃ for 2-3h. After the reaction was completed, 3.25g of hydroxyethyl methacrylate was added, and the reaction was continued at 60℃ for 4h. After the reaction was completed, the first reaction product liquid was obtained. The first reaction product liquid system was cooled to below 35℃, and 60g of deionized water was added dropwise for dispersion. The reaction was carried out for 0.5h, and 5g of nano-silver-supported aliphatic amine-modified graphene oxide was added. The temperature was raised to 40-50℃ and the reaction was carried out for 2-4h to obtain the final product, weather-resistant antibacterial polyurethane coating.

[0057] Example 3

[0058] This embodiment provides a weather-resistant and antibacterial polyurethane coating. The raw materials of the polyurethane coating include polyether triol, isophorone diisocyanate, hydroxyethyl methacrylate, and nano-silver-supported aliphatic amine-modified graphene oxide.

[0059] The nano-silver-supported aliphatic amine-modified graphene oxide in this embodiment was prepared as follows:

[0060] 0.6 g of graphene oxide powder was dispersed in 12 mL of deionized water and ultrasonically dispersed for 30 min to obtain an aqueous dispersion of graphene oxide, which was then poured into a three-necked flask.

[0061] Dissolve 0.9 g of dodecylamine in 90 mL of 85% ethanol solution to obtain a fatty amine ethanol solution, and pour it into a three-necked flask;

[0062] The aqueous dispersion of graphene oxide was mixed with an ethanol solution of a fatty amine and refluxed at 90°C for 20 h. After the reaction was completed, the product was filtered and washed 3-4 times with anhydrous ethanol. Finally, it was vacuum dried at 60°C for 6-12 h to obtain aliphatic amine modified graphene oxide.

[0063] 0.1 g of aliphatic amine-modified graphene oxide was dispersed in 50 mL of an ethanol solution with an alcohol-to-water ratio of 4:1 and ultrasonically dispersed for 30 min. Then, 10 mL of silver nitrate solution with a concentration of 0.002 g / mL was added, and the mixture was placed in a hydrothermal reactor. 5 mL of sodium hydroxide solution with a concentration of 0.002 g / mL was then added dropwise. After the addition was complete, the hydrothermal reactor was placed in an oven at 160 °C for 24 h. After the reaction was completed, the product was filtered and separated, washed 3-4 times with ethanol, and dried in a vacuum chamber at 60 °C for 6-12 h to obtain nano-silver-supported aliphatic amine-modified graphene oxide.

[0064] The weather-resistant and antibacterial polyurethane coating in this embodiment is prepared as follows:

[0065] Under conditions of 50-60℃ in the reactor, 10g of polyether triol and 10g of N-methylpyrrolidone were added and stirred. A mixture of 0.025g dibutyltin dilaurate and 5.6g isophorone diisocyanate was added dropwise to the reactor. The temperature was raised to 80℃ and reacted for 2-2.5h. The temperature was then lowered to below 50℃, and 10g of dimethylolpropionic acid was added. The reaction was continued at 60℃ for 2-3h. After the reaction was completed, 3.25g of hydroxyethyl methacrylate was added, and the reaction was continued at 60℃ for 4h. After the reaction was completed, the first reaction product liquid was obtained. The first reaction product liquid system was cooled to below 35℃, and 60g of deionized water was added dropwise for dispersion. The reaction was carried out for 0.5h, and 2g of nano-silver-supported aliphatic amine-modified graphene oxide was added. The temperature was raised to 40-50℃ and the reaction was carried out for 2-4h to obtain the final product, weather-resistant antibacterial polyurethane coating.

[0066] Comparative Example 1

[0067] This comparative example provides a polyurethane coating, which is prepared by the following method:

[0068] Maintain the temperature inside the reactor at 50-60℃, add 10g of polyether triol and N-methylpyrrolidone and stir. Add a mixture of 0.025g dibutyltin dilaurate and 5.6g isophorone diisocyanate dropwise to the reactor. Raise the temperature to 80℃ and react for 2-2.5 hours. Cool the temperature to below 50℃, add dimethylolpropionic acid and continue the reaction at 60℃ for 2-3 hours. After the reaction is complete, add 3.25g hydroxyethyl methacrylate and continue the reaction at 60℃ for 4 hours. After the reaction is complete, cool the system to below 35℃, add 60g of deionized water for dispersion, raise the temperature to 40-50℃ and react for 2-4 hours to obtain the final product, polyurethane coating.

[0069] Comparative Example 2

[0070] This comparative example provides a polyurethane coating, which is prepared by the following method:

[0071] Maintain the temperature inside the reactor at 50-60℃, add 10g of polyether triol and N-methylpyrrolidone and stir. Add a mixture of 0.025g dibutyltin dilaurate and 5.6g isophorone diisocyanate dropwise to the reactor. Heat to 80℃ and react for 2-2.5h. Cool down to below 50℃, add dimethylolpropionic acid and continue the reaction at 60℃ for 2-3h. After the reaction is complete, add 3.25g hydroxyethyl methacrylate and continue the reaction at 60℃ for 4h. After the reaction is complete, cool the system to below 35℃, add 60g of deionized water for dispersion, and react for 0.5h. Add 5g of nano silver, heat to 40-50℃, and react for 2-4h to obtain the final product, polyurethane coating.

[0072] Comparative Example 3

[0073] This comparative example provides a polyurethane coating, which is prepared by the following method:

[0074] Maintain the temperature inside the reactor at 50-60℃, add 10g of polyether triol and N-methylpyrrolidone and stir. Add a mixture of 0.025g dibutyltin dilaurate and 5.6g isophorone diisocyanate dropwise to the reactor. Heat to 80℃ and react for 2-2.5h. Cool down to below 50℃, add dimethylolpropionic acid and continue the reaction at 60℃ for 2-3h. After the reaction is complete, add 3.25g hydroxyethyl methacrylate and continue the reaction at 60℃ for 4h. After the reaction is complete, cool the system to below 35℃, add 60g of deionized water for dispersion, and react for 0.5h. Add 5g of graphene oxide, heat to 40-50℃, and react for 2-4h to obtain the final product, polyurethane coating.

[0075] Comparative Example 4

[0076] This comparative example provides a polyurethane coating, which is prepared by the following method:

[0077] (1) 0.1 g of graphene oxide was dispersed in 50 mL of ethanol solution with an alcohol-to-water ratio of 4:1 and ultrasonically dispersed for 30 min. Then, 10 mL of silver nitrate solution with a concentration of 0.002 g / mL was prepared and mixed with the graphene oxide dispersion and placed in a hydrothermal reactor. 5 mL of sodium hydroxide solution with a concentration of 0.002 g / mL was added dropwise. After the addition was completed, the hydrothermal reactor was placed in an oven at 160 °C for 24 h. After the reaction was completed, the product was filtered and separated, washed with ethanol 3-4 times, and dried in a vacuum box at 60 °C for 6-12 h to obtain nano-silver supported graphene oxide, which was stored for later use.

[0078] (2) Keep the temperature inside the reactor at 50-60℃, add 10g of polyether triol and N-methylpyrrolidone and stir. Add a mixture of 0.025g of dibutyltin dilaurate and 5.6g of isophorone diisocyanate to the reactor dropwise. Heat to 80℃ and react for 2-2.5h. Cool down to below 50℃, add dimethylolpropionic acid, and continue to react at 60℃ for 2-3h. After the reaction is complete, add 3.25g of hydroxyethyl methacrylate and continue to react at 60℃ for 4h. After the reaction is complete, cool the system to below 35℃, add 60g of deionized water for dispersion, and react for 0.5h. Add 5g of nano-silver supported graphene oxide, heat to 40-50℃, and react for 2-4h to obtain the final product, polyurethane coating.

[0079] The performance of the polyurethane coatings obtained in Examples 1-3 and Comparative Examples 1-4 was tested.

[0080] The performance testing method is as follows:

[0081] Antibacterial performance: The antibacterial performance of polyurethane coatings against Escherichia coli was tested according to GB / T21866-2008 "Determination of antibacterial properties and antibacterial effects of antibacterial coatings (films)".

[0082] Polyurethane coating is applied onto a clean polytetrafluoroethylene dish to form a coating film. The film is then dried at room temperature and kept clean for performance testing.

[0083] Hardness determination of coating film:

[0084] The hardness of the coating film was determined using a KYLX-A ​​Shore hardness tester according to the GB527 standard method.

[0085] Determination of tensile strength and elongation at break of coating film:

[0086] The test was performed using a KY8000A electronic universal testing machine. The test strips were prepared according to GB / T528-92: the coating film was cut into strips with a length of 5cm and a width of 4cm, and tested under pressure on a tensile testing machine with a clamp separation speed of 50mm / min.

[0087] High and low temperature aging test of coating film:

[0088] The test strips were prepared according to GB / T528-92: the coating film was cut into strips 5cm long and 4cm wide, placed in a high and low temperature chamber, and placed at -50℃ to 50℃ (3℃ / min) for 24 hours. The test strips were then tested on a tensile testing machine according to the standard. Five samples were used for each test, and the median value of the test results was taken.

[0089] Water and acid resistance test of coating film:

[0090] The swelling rate of the coating film after immersion in a solution medium for 24 hours was tested to characterize its water and acid resistance; a lower swelling rate indicates better water and acid resistance. A volume of coating film (ml) was weighed and successively immersed in deionized water and hydrochloric acid solution (pH 5.6). After 24 hours, the film was removed, and the water and hydrochloric acid solution on the surface were wiped off with filter paper. The mass (m2) was then measured. The swelling rate can be calculated using the following formula:

[0091]

[0092] The test results are shown in Table 1 below:

[0093] Table 1

[0094]

[0095]

[0096] As can be seen from the results in Table 1, the polyurethane coating prepared by the method of the present invention has good antibacterial effect, excellent mechanical properties, significantly improved water and acid resistance, and excellent high and low temperature aging performance.

[0097] In summary,

[0098] The weather-resistant and antibacterial polyurethane coating of this invention uses nano-silver-supported aliphatic amine-modified graphene oxide as a special functional additive. This effectively integrates unstable materials such as graphene and nano-silver into the polyurethane coating system, significantly improving the weather resistance, antibacterial properties, and mechanical properties of the polyurethane coating. The weather-resistant and antibacterial polyurethane coating obtained by this invention exhibits good mechanical properties, strong antibacterial activity, strong water and acid resistance, good high and low temperature aging performance, long service life, and wide range of applications.

[0099] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of the invention as described above, which are not provided in the details for the sake of brevity.

[0100] The embodiments of this invention are intended to cover all such substitutions, modifications, and variations falling within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this invention should be included within the protection scope of this invention.

Claims

1. A method for preparing a weather-resistant antibacterial polyurethane coating, characterized in that: The raw materials for this polyurethane coating include polyether triol, isophorone diisocyanate, hydroxyethyl methacrylate, nano-silver supported fatty amine modified graphene oxide, N-methylpyrrolidone, dibutyltin dilaurate, and dimethylolpropionic acid. The nano-silver-supported aliphatic amine-modified graphene oxide was prepared by the following method: Graphene oxide powder was dispersed in deionized water to obtain an aqueous dispersion of graphene oxide. A fatty amine is dissolved in an ethanol solution to obtain a fatty amine ethanol solution; Aqueous dispersion of graphene oxide and ethanol solution of fatty amine were mixed and reacted. After the reaction was completed, the residue was filtered and dried to obtain fatty amine modified graphene oxide. The aliphatic amine-modified graphene oxide was dispersed in a 75-95% ethanol solution, then silver nitrate solution was added, mixed well, and then sodium hydroxide solution was added dropwise. After the addition was completed, the reaction was carried out at 150-180℃ for 20-26 hours. After the reaction was completed, the product was filtered and dried to obtain nano-silver-supported aliphatic amine-modified graphene oxide. The preparation of the weather-resistant antibacterial polyurethane coating includes the following steps: Polyether triol and N-methylpyrrolidone were mixed at 50-60℃, and then a mixture of dibutyltin dilaurate and isophorone diisocyanate was added dropwise. The mixture was heated for 1.5-3 hours and then cooled to below 50℃. Dimethylolpropionic acid was then added to continue the reaction. After the reaction was completed, hydroxyethyl methacrylate was added to continue the reaction to obtain the liquid product of the first reaction. Deionized water was added dropwise to the first reaction product liquid for dispersion reaction, and then nano-silver-supported fatty amine-modified graphene oxide was added. The temperature was raised to 40-50℃ and the reaction was carried out for 2-4 hours to obtain weather-resistant antibacterial polyurethane coating.

2. The method for preparing the weather-resistant antibacterial polyurethane coating according to claim 1, characterized in that: The molar ratio of the polyether triol to the isophorone diisocyanate is 2:1 to 1:

1.

3. The method for preparing the weather-resistant antibacterial polyurethane coating according to claim 1, characterized in that: The amount of the nano-silver-supported fatty amine-modified graphene oxide is 10%-50% of the mass of the polyether triol.

4. The method for preparing the weather-resistant antibacterial polyurethane coating according to claim 1, characterized in that: The mass ratio of the graphene oxide powder to the fatty amine is 1:2-2:1; On a dry weight basis, the mass ratio of the silver nitrate solution to the fatty amine-modified graphene oxide is 1:5 to 1:

10.

5. The method for preparing the weather-resistant antibacterial polyurethane coating according to claim 1, characterized in that: The fatty amine is a C8-C18 fatty amine.

6. The method for preparing the weather-resistant antibacterial polyurethane coating according to claim 1, characterized in that: In the step of mixing and reacting the graphene oxide aqueous dispersion and the fatty amine ethanol solution, and then filtering and collecting the filter residue after the reaction is completed, the reaction temperature is 80-100℃ and the reaction time is 18-24h.

7. The method for preparing the weather-resistant antibacterial polyurethane coating according to claim 1, characterized in that: The reaction temperature for the continued reaction is 55-65℃, and the reaction time is 1-5 hours. The dispersion reaction is carried out at a temperature of 30-40℃ for 0.5-1 hour. The reaction temperature of the heating reaction is 75-85℃; And / or, by weight, the mass of the dibutyltin dilaurate is 0.2-0.5% of the mass of the polyether triol.

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