Process for preparing a weatherable polyurethane coating material

Abstract

This invention discloses a preparation process for a weather-resistant polyurethane coating material, relating to the field of coating material technology. In preparing the weather-resistant polyurethane coating material, sericite is pretreated and then reacted with cinnamaldehyde to obtain modified sericite; a high-efficiency flame retardant is prepared by reacting 3,5-diamino-1,2,4-triazole sequentially with p-methoxybenzaldehyde and dimethyl phosphite using a one-pot method; polytetrahydrofuran diol, benzoyl diols, and 4,4'-dicyclohexylmethane diisocyanate are polymerized to obtain polyurethane; the polyurethane, high-efficiency flame retardant, and modified sericite are mixed using DMF as a solvent to formulate a polyurethane coating, which is then dried to obtain the polyurethane coating material. The polyurethane coating material prepared by the process provided by this invention possesses the advantages of weather resistance, flame retardancy, and antibacterial properties.

Description

Technical Field

[0001] This invention relates to the field of coating materials technology, specifically to a preparation process for a weather-resistant polyurethane coating material. Background Technology

[0002] Polyurethane coatings are used in construction, transportation, energy, marine engineering, electronics, and outdoor facilities. When polyurethane coatings are exposed to outdoor environments for extended periods, they can exhibit powdering, cracking, blistering, and peeling due to UV radiation and thermal cycling, affecting their appearance and lifespan. Furthermore, polyurethane is inherently flammable, posing a fire hazard when used over large areas. In public places such as hospitals, nursing homes, subways, buses, and airplanes, large numbers of microorganisms and bacteria exist, and polyurethane coatings, lacking antibacterial properties or possessing only weak antibacterial capabilities, easily promote bacterial growth and spread. Traditional polyurethane coatings have limited performance characteristics, hindering their widespread application. This application utilizes a simple modification process to prepare a polyurethane coating material that combines weather resistance, flame retardancy, and antibacterial properties, extending its lifespan and improving its safety and reliability, thus meeting the application needs of various fields. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a preparation process for a weather-resistant polyurethane coating material. The polyurethane coating material prepared by the preparation process provided by this invention has excellent weather resistance, antibacterial and flame retardant properties, extends the service life and safety and reliability of the polyurethane coating material, and meets its application needs in various fields.

[0004] A preparation process for a weather-resistant polyurethane coating material, wherein the preparation process for the weather-resistant polyurethane coating material is as follows: S1: Pretreated sericite was prepared by reacting sericite with 3-aminopropyltriethoxysilane, and then reacted with cinnamaldehyde to obtain modified sericite. S2: A highly efficient flame retardant was prepared by reacting 3,5-diamino-1,2,4-triazole with p-methoxybenzaldehyde and dimethyl phosphite in sequence using a one-pot method. S3: Benzoyl diols are prepared by reacting 3,4,5-trimethoxybenzoyl chloride with trimethylolpropane. S4: Polyurethane is prepared by polymerizing polytetrahydrofuran diol, benzoyl diol and 4,4'-dicyclohexylmethane diisocyanate. S5: Polyurethane, high-efficiency flame retardant and modified sericite are mixed with DMF as solvent to prepare polyurethane coating; the polyurethane coating is dried to obtain polyurethane coating material.

[0005] Preferably, the preparation process of the pretreated sericite in step S1 is as follows: sericite and 3-aminopropyltriethoxysilane are weighed at a mass ratio of 1:(0.06~0.08); 3-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water are mixed at a mass ratio of 1:(6~8):(10~14), stirred at 50~60℃ for 10~20 min to prepare a modification solution; sericite and anhydrous ethanol are mixed at a mass ratio of 1:(40~50), sonicated for 10~20 min, the modification solution is added, stirred at 70~80℃ for 2~3 h, filtered, washed with anhydrous ethanol, and dried at 70~80℃ for 5~6 h to obtain the pretreated sericite.

[0006] Preferably, the sericite has a particle size of 800 mesh and a purity of 99%.

[0007] Preferably, the preparation process of the modified sericite in step S1 is as follows: pretreated sericite and anhydrous ethanol are mixed at a mass ratio of 1:(40~50), sonicated for 10~20 min, cinnamaldehyde is added at 0.6~0.8 times the mass of the pretreated sericite, the mixture is heated to 50~60℃ and stirred for 6~8 h, filtered, washed with anhydrous ethanol, and dried at 70~80℃ for 10~14 h to obtain the modified sericite.

[0008] Preferably, the preparation process of the high-efficiency flame retardant in step S2 is as follows: 3,5-diamino-1,2,4-triazole, p-methoxybenzaldehyde, and dimethyl phosphite are weighed in a molar ratio of 1:2:2; 3,5-diamino-1,2,4-triazole and p-methoxybenzaldehyde are dissolved in anhydrous ethanol at 24-30 times the mass of 3,5-diamino-1,2,4-triazole, and the mixture is stirred and reacted at 60-70°C for 8-10 hours; dimethyl phosphite is added, and the mixture is stirred and reacted for another 16-20 hours; the mixture is then evaporated under reduced pressure and dried under vacuum at 50-60°C for 20-24 hours to obtain the high-efficiency flame retardant.

[0009] Preferably, the preparation process of the benzoyl diol in step S3 is as follows: 3,4,5-trimethoxybenzoyl chloride and trimethylolpropane are dissolved in tetrahydrofuran at a molar ratio of 1:1, which is 10 to 14 times the mass of 3,4,5-trimethoxybenzoyl chloride. An equimolar amount of triethylamine is added, and the mixture is heated to 60 to 66°C and reacted for 7 to 8 hours. The mixture is then evaporated under reduced pressure, washed with cold water at 0 to 5°C, and dried under vacuum at 60 to 70°C for 8 to 10 hours to obtain the benzoyl diol.

[0010] Preferably, the reaction principle of the benzoyl diol is as follows: .

[0011] Preferably, the polyurethane preparation process in step S4 is as follows: Weigh polytetrahydrofuran diol, benzoyl diol, and 4,4'-dicyclohexylmethane diisocyanate in a molar ratio of 6:(4~5):(11~13); mix the polytetrahydrofuran diol and benzoyl diol, add 3~4 times the mass of N,N-dimethylformamide to the polytetrahydrofuran diol, stir at 70~80℃ for 10~20 min, and add... 4,4'-Dicyclohexylmethane diisocyanate was reacted with 0.001 to 0.003 times the mass of 4,4'-dicyclohexylmethane diisocyanate in dibutyltin dilaurate. The mixture was stirred at 75 to 85 °C for 2 to 3 hours under nitrogen protection. The reaction was then quenched with 0.2 to 0.3 times the molar mass of 4,4'-dicyclohexylmethane diisocyanate in anhydrous ethanol. The mixture was then vacuum dried at 50 to 60 °C for 20 to 24 hours to obtain polyurethane.

[0012] Preferably, the polytetrahydrofuran diol has a molecular weight of 1000.

[0013] Preferably, the preparation process of the polyurethane coating material in step S5 is as follows: 70-80 parts of polyurethane, 10-14 parts of high-efficiency flame retardant, and 6-7 parts of modified sericite are mixed, and the solid content is adjusted to 50%-60% with the solvent N,N-dimethylformamide to obtain a polyurethane coating; the polyurethane coating is poured into a mold and dried at 80-100℃ for 20-24 hours, and then naturally dried at room temperature for 24 hours to obtain a weather-resistant polyurethane coating material.

[0014] The beneficial effects of this invention are as follows: Pretreated sericite was prepared by reacting sericite with 3-aminopropyltriethoxysilane, resulting in a large amount of amino groups on the pretreated sericite. Modified sericite was then obtained by reacting it with cinnamaldehyde in a Schiff base reaction. Sericite has UV shielding properties, absorbing and reflecting ultraviolet light. Surface pretreatment of sericite with a silane coupling agent can improve its dispersibility in polyurethane coatings. Cinnamaldehyde, with antibacterial properties, is chemically bonded to the surface of the sericite, enhancing the antibacterial ability of the polyurethane coating.

[0015] A high-efficiency flame retardant was prepared by reacting 3,5-diamino-1,2,4-triazole sequentially with p-methoxybenzaldehyde and dimethyl phosphite using a one-pot method. The amino group on 3,5-diamino-1,2,4-triazole reacted with the aldehyde group on p-methoxybenzaldehyde in a Schiff base reaction, followed by an addition reaction with the PH bond on dimethyl phosphite to obtain the high-efficiency flame retardant. The high-efficiency flame retardant contains nitrogen and phosphorus elements in its structure, which gives it a more efficient flame retardant ability compared to flame retardants with single elements, thus improving the flame retardant ability of polyurethane coatings.

[0016] 3,4,5-Trimethoxybenzoyl chloride and trimethylolpropane are reacted to prepare benzoyl diols. The diol on the benzoyl diol can participate in the polymerization reaction of polyurethane. A 3,4,5-trimethoxybenzoic acid ester structure is introduced into the side chain of polyurethane. The 3,4,5-trimethoxybenzoic acid ester structure can absorb ultraviolet rays and work synergistically with sericite, an inorganic ultraviolet protection material, to further enhance the weather resistance of polyurethane coatings. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: A preparation process for a weather-resistant polyurethane coating material, wherein the preparation process for the weather-resistant polyurethane coating material is as follows: S1: Weigh sericite and 3-aminopropyltriethoxysilane at a mass ratio of 1:0.06; mix 3-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water at a mass ratio of 1:6:10, stir at 50℃ for 20 min to prepare a modification solution; mix sericite and anhydrous ethanol at a mass ratio of 1:40, sonicate for 10 min, add the modification solution, stir at 70℃ for 3 h, filter, wash with anhydrous ethanol, and dry at 70℃ for 6 h to obtain pretreated sericite; mix pretreated sericite and anhydrous ethanol at a mass ratio of 1:40, sonicate for 10 min, add 0.6 times the mass of cinnamaldehyde of pretreated sericite, heat to 50℃ and stir for 8 h, filter, wash with anhydrous ethanol, and dry at 70℃ for 14 h to obtain modified sericite; S2: Weigh 3,5-diamino-1,2,4-triazole, p-methoxybenzaldehyde, and dimethyl phosphite in a molar ratio of 1:2:2; dissolve 3,5-diamino-1,2,4-triazole and p-methoxybenzaldehyde in anhydrous ethanol at 24 times the mass of 3,5-diamino-1,2,4-triazole, stir and react at 60°C for 10 h, add dimethyl phosphite, continue stirring and react for 20 h, rotary evaporate under reduced pressure, and vacuum dry at 50°C for 24 h to obtain a high-efficiency flame retardant; S3: 3,4,5-trimethoxybenzoyl chloride and trimethylolpropane were dissolved in tetrahydrofuran at a molar ratio of 1:1, which was 10 times the mass of 3,4,5-trimethoxybenzoyl chloride. An equimolar amount of triethylamine was added, and the mixture was heated to 60°C and reacted for 8 hours. The mixture was then evaporated under reduced pressure, washed with cold water at 0°C, and dried under vacuum at 60°C for 10 hours to obtain benzoyl diols. S4: Weigh out polytetrahydrofurandiol, benzoyl diol, and 4,4'-dicyclohexylmethane diisocyanate in a molar ratio of 6:4:11; mix the polytetrahydrofurandiol and benzoyl diol, add N,N-dimethylformamide in 3 times the mass of the polytetrahydrofurandiol, stir at 70°C for 20 min, add 4,4'-dicyclohexylmethane diisocyanate, add dibutyltin dilaurate in 0.001 times the mass of the 4,4'-dicyclohexylmethane diisocyanate, stir at 75°C for 3 h under nitrogen protection, add anhydrous ethanol in 0.2 times the molar mass of the 4,4'-dicyclohexylmethane diisocyanate to quench the reaction, and vacuum dry at 50°C for 24 h to obtain polyurethane; S5: Mix 70 parts polyurethane, 10 parts high-efficiency flame retardant, and 6 parts modified sericite, and adjust the solid content to 50% with N,N-dimethylformamide solvent to obtain a polyurethane coating; pour the polyurethane coating into a mold, dry at 80℃ for 24 hours, and then allow to air dry at room temperature for 24 hours to obtain a weather-resistant polyurethane coating material.

[0019] Example 2: A preparation process for a weather-resistant polyurethane coating material, wherein the preparation process for the weather-resistant polyurethane coating material is as follows: S1: Weigh sericite and 3-aminopropyltriethoxysilane at a mass ratio of 1:0.07; mix 3-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water at a mass ratio of 1:7:12, stir at 55℃ for 15 min to prepare a modification solution; mix sericite and anhydrous ethanol at a mass ratio of 1:45, sonicate for 15 min, add the modification solution, stir at 75℃ for 2.5 h, filter, wash with anhydrous ethanol, and dry at 75℃ for 5.5 h to obtain pretreated sericite; mix pretreated sericite and anhydrous ethanol at a mass ratio of 1:45, sonicate for 15 min, add 0.7 times the mass of cinnamaldehyde of pretreated sericite, heat to 55℃ and stir for 7 h, filter, wash with anhydrous ethanol, and dry at 75℃ for 12 h to obtain modified sericite; S2: Weigh 3,5-diamino-1,2,4-triazole, p-methoxybenzaldehyde, and dimethyl phosphite in a molar ratio of 1:2:2; dissolve 3,5-diamino-1,2,4-triazole and p-methoxybenzaldehyde in anhydrous ethanol at 27 times the mass of 3,5-diamino-1,2,4-triazole, stir and react at 65°C for 9 hours, add dimethyl phosphite, continue stirring and react for 18 hours, rotary evaporate under reduced pressure, and vacuum dry at 55°C for 22 hours to obtain a high-efficiency flame retardant; S3: 3,4,5-trimethoxybenzoyl chloride and trimethylolpropane were dissolved in tetrahydrofuran at a molar ratio of 1:1, which was 12 times the mass of 3,4,5-trimethoxybenzoyl chloride. An equimolar amount of triethylamine was added, and the mixture was heated to 63°C and reacted for 7.5 h. The mixture was then evaporated under reduced pressure, washed with cold water at 2°C, and dried under vacuum at 65°C for 9 h to obtain benzoyl diols. S4: Weigh out polytetrahydrofurandiol, benzoyl diol, and 4,4'-dicyclohexylmethane diisocyanate in a molar ratio of 6:4.5:12; mix the polytetrahydrofurandiol and benzoyl diol, add N,N-dimethylformamide at 3.5 times the mass of the polytetrahydrofurandiol, stir at 75°C for 15 min, add 4,4'-dicyclohexylmethane diisocyanate, add dibutyltin dilaurate at 0.002 times the mass of the 4,4'-dicyclohexylmethane diisocyanate, stir and react at 80°C for 2.5 h under nitrogen protection, add anhydrous ethanol at 0.25 times the molar mass of the 4,4'-dicyclohexylmethane diisocyanate to quench the reaction, and vacuum dry at 55°C for 22 h to obtain polyurethane; S5: Mix 75 parts polyurethane, 12 parts high-efficiency flame retardant, and 6.5 parts modified sericite, and adjust the solid content to 55% with N,N-dimethylformamide solvent to obtain a polyurethane coating; pour the polyurethane coating into a mold, dry at 90℃ for 22 hours, and then allow to air dry at room temperature for 24 hours to obtain a weather-resistant polyurethane coating material.

[0020] Example 3: A preparation process for a weather-resistant polyurethane coating material, wherein the preparation process for the weather-resistant polyurethane coating material is as follows: S1: Weigh sericite and 3-aminopropyltriethoxysilane at a mass ratio of 1:0.08; mix 3-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water at a mass ratio of 1:8:14, stir at 60℃ for 10 min to prepare a modification solution; mix sericite and anhydrous ethanol at a mass ratio of 1:50, sonicate for 20 min, add the modification solution, stir at 80℃ for 2 h, filter, wash with anhydrous ethanol, and dry at 80℃ for 5 h to obtain pretreated sericite; mix pretreated sericite and anhydrous ethanol at a mass ratio of 1:50, sonicate for 20 min, add 0.8 times the mass of cinnamaldehyde of the pretreated sericite, heat to 60℃ and stir for 6 h, filter, wash with anhydrous ethanol, and dry at 80℃ for 10 h to obtain modified sericite; S2: Weigh 3,5-diamino-1,2,4-triazole, p-methoxybenzaldehyde, and dimethyl phosphite in a molar ratio of 1:2:2; dissolve 3,5-diamino-1,2,4-triazole and p-methoxybenzaldehyde in anhydrous ethanol at 30 times the mass of 3,5-diamino-1,2,4-triazole, stir and react at 70°C for 8 hours, add dimethyl phosphite, continue stirring and react for 16 hours, rotary evaporate under reduced pressure, and vacuum dry at 60°C for 20 hours to obtain a high-efficiency flame retardant; S3: 3,4,5-trimethoxybenzoyl chloride and trimethylolpropane were dissolved in tetrahydrofuran at a molar ratio of 1:1, which was 14 times the mass of 3,4,5-trimethoxybenzoyl chloride. An equimolar amount of triethylamine was added, and the mixture was heated to 66°C and reacted for 7 hours. The mixture was then evaporated under reduced pressure, washed with cold water at 5°C, and dried under vacuum at 70°C for 8 hours to obtain benzoyl diols. S4: Weigh out polytetrahydrofurandiol, benzoyl diol, and 4,4'-dicyclohexylmethane diisocyanate in a molar ratio of 6:5:13; mix the polytetrahydrofurandiol and benzoyl diol, add N,N-dimethylformamide in 4 times the mass of the polytetrahydrofurandiol, stir at 80°C for 10 min, add 4,4'-dicyclohexylmethane diisocyanate, add dibutyltin dilaurate in 0.003 times the mass of the 4,4'-dicyclohexylmethane diisocyanate, stir and react at 85°C for 2 h under nitrogen protection, add anhydrous ethanol in 0.3 times the molar mass of the 4,4'-dicyclohexylmethane diisocyanate to quench the reaction, and vacuum dry at 60°C for 20 h to obtain polyurethane; S5: Mix 80 parts of polyurethane, 14 parts of high-efficiency flame retardant, and 7 parts of modified sericite, and adjust the solid content to 60% with the solvent N,N-dimethylformamide to obtain a polyurethane coating; pour the polyurethane coating into a mold, dry at 100℃ for 20 hours, and then allow to air dry at room temperature for 24 hours to obtain a weather-resistant polyurethane coating material.

[0021] Comparative Example 1: The difference between the preparation process of the weather-resistant polyurethane coating material provided in this embodiment and that in embodiment 2 lies in step S5, where “modified sericite” in step S5 is replaced with “pretreated sericite”.

[0022] Comparative Example 2: The difference between the preparation process of the weather-resistant polyurethane coating material provided in this embodiment and that in embodiment 2 is that step S2 is omitted and "high-efficiency flame retardant" is not added in step S5.

[0023] Comparative Example 3: The difference between the preparation process of the weather-resistant polyurethane coating material provided in this embodiment and that in embodiment 2 is that step S3 is omitted, and "benzoyl diol" in step S4 is replaced with "1,4-butanediol".

[0024] Test case Test Example 1: Weather Resistance Referring to GB / T 1040.3-2006, the examples and comparative examples were prepared into 150 mm × 10 mm × 1 mm specimens, and their tensile strength F0 was tested at a tensile rate of 50 mm / min. The specimens were irradiated with a 200W, 365nm ultraviolet lamp for 10 days. After the irradiation, their tensile strength F1 was tested, and the tensile strength retention rate x (%) of the specimens after ultraviolet aging was calculated.

[0025]

[0026] Test Example 2: Flame Retardant Performance Referring to GB / T 2406.2-2009, the limiting oxygen index (LOI) of the test examples and comparative examples was 100mm×10mm×4mm.

[0027] Test Example 3: Antibacterial Properties The antibacterial properties of the coating were tested using the film application method according to GB / T 21866 standard, with Escherichia coli as the test strain.

[0028] Liquid culture medium: 10g peptone, 3g beef extract powder, 5g sodium chloride, 1L deionized water; Solid culture medium: 10g peptone, 3g beef extract powder, 5g sodium chloride, 15g agar, 1L deionized water; Escherichia coli was activated and diluted with liquid culture medium to a concentration of 5.0 × 10⁻⁶. 5 CFU / mL, use a pipette to take 400 μL of bacterial suspension and spread it on the weather-resistant polyurethane coating material prepared in the examples and comparative examples. Then cover it with a layer of sterile polyethylene film and incubate it in a 37℃ incubator for 12 h. After the incubation, dilute the sample with sterile water for 1 h, take 200 μL and spread it evenly on the solid culture medium. Incubate it in reverse in a 37℃ incubator for 12 h, observe the growth of colonies and calculate the number of colonies, and calculate the antibacterial rate (%).

[0029]

[0030] Data Analysis: The tensile strength retention rates of Examples 1-3 were significantly higher than those of Comparative Example 3, indicating that introducing a 3,4,5-trimethoxybenzoate structure into the polyurethane side chain can improve the weather resistance of the coating. The limiting oxygen index (LOI) values ​​of Examples 1-3 are significantly greater than those of Comparative Example 2, indicating that adding the high-efficiency flame retardant prepared in this application to the polyurethane coating can improve the flame retardant ability of the polyurethane coating.

[0031] The antibacterial rates of Examples 1-3 were significantly greater than those of Comparative Example 1, indicating that loading cinnamaldehyde onto sericite in this application improved the antibacterial ability of the coating.

[0032] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A preparation process for a weather-resistant polyurethane coating material, characterized in that, The preparation process of the weather-resistant polyurethane coating material is as follows: S1: Pretreated sericite was prepared by reacting sericite with 3-aminopropyltriethoxysilane, and then reacted with cinnamaldehyde to obtain modified sericite. S2: A highly efficient flame retardant was prepared by reacting 3,5-diamino-1,2,4-triazole with p-methoxybenzaldehyde and dimethyl phosphite in sequence using a one-pot method. S3: Benzoyl diols are prepared by reacting 3,4,5-trimethoxybenzoyl chloride with trimethylolpropane. S4: Polyurethane is prepared by polymerizing polytetrahydrofuran diol, benzoyl diol and 4,4'-dicyclohexylmethane diisocyanate. S5: Polyurethane, high-efficiency flame retardant and modified sericite are mixed with DMF as solvent to prepare polyurethane coating; the polyurethane coating is dried to obtain polyurethane coating material.

2. The preparation process of the weather-resistant polyurethane coating material according to claim 1, characterized in that, The preparation process of the pretreated sericite in step S1 is as follows: sericite and 3-aminopropyltriethoxysilane are weighed at a mass ratio of 1:(0.06~0.08); 3-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water are mixed at a mass ratio of 1:(6~8):(10~14), stirred at 50~60℃ for 10~20 min to prepare a modification solution; sericite and anhydrous ethanol are mixed at a mass ratio of 1:(40~50), sonicated for 10~20 min, the modification solution is added, stirred at 70~80℃ for 2~3 h, filtered, washed with anhydrous ethanol, and dried at 70~80℃ for 5~6 h to obtain the pretreated sericite.

3. The preparation process of the weather-resistant polyurethane coating material according to claim 2, characterized in that, The sericite has a particle size of 800 mesh and a purity of 99%.

4. The preparation process of the weather-resistant polyurethane coating material according to claim 1, characterized in that, The preparation process of the modified sericite in step S1 is as follows: pretreated sericite and anhydrous ethanol are mixed at a mass ratio of 1:(40~50), sonicated for 10~20 min, cinnamaldehyde of 0.6~0.8 times the mass of the pretreated sericite is added, the mixture is heated to 50~60℃ and stirred for 6~8 h, filtered, washed with anhydrous ethanol, and dried at 70~80℃ for 10~14 h to obtain the modified sericite.

5. The preparation process of the weather-resistant polyurethane coating material according to claim 1, characterized in that, The preparation process of the high-efficiency flame retardant in step S2 is as follows: Weigh 3,5-diamino-1,2,4-triazole, p-methoxybenzaldehyde and dimethyl phosphite in a molar ratio of 1:2:2; Dissolve 3,5-diamino-1,2,4-triazole and p-methoxybenzaldehyde in anhydrous ethanol at 24-30 times the mass of 3,5-diamino-1,2,4-triazole, stir and react at 60-70℃ for 8-10 hours, add dimethyl phosphite, continue stirring and reacting for 16-20 hours, evaporate under reduced pressure, and vacuum dry at 50-60℃ for 20-24 hours to obtain the high-efficiency flame retardant.

6. The preparation process of the weather-resistant polyurethane coating material according to claim 1, characterized in that, The preparation process of the benzoyl diol in step S3 is as follows: 3,4,5-trimethoxybenzoyl chloride and trimethylolpropane are dissolved in tetrahydrofuran at a molar ratio of 1:1, which is 10 to 14 times the mass of 3,4,5-trimethoxybenzoyl chloride. An equimolar amount of triethylamine is added, and the mixture is heated to 60 to 66°C and reacted for 7 to 8 hours. The mixture is then evaporated under reduced pressure, washed with cold water at 0 to 5°C, and dried under vacuum at 60 to 70°C for 8 to 10 hours to obtain the benzoyl diol.

7. The preparation process of the weather-resistant polyurethane coating material according to claim 1, characterized in that, The reaction principle of the benzoyl diols in step S3 is as follows: 。 8. The preparation process of the weather-resistant polyurethane coating material according to claim 1, characterized in that, The preparation process of polyurethane in step S4 is as follows: Weigh polytetrahydrofurandiol, benzoyl diol, and 4,4'-dicyclohexylmethane diisocyanate in a molar ratio of 6:(4~5):(11~13); mix polytetrahydrofurandiol and benzoyl diol, add 3~4 times the mass of N,N-dimethylformamide to polytetrahydrofurandiol, stir at 70~80℃ for 10~20 min, add 4,4'-dicyclohexylmethane diisocyanate, add 0.001~0.003 times the mass of 4,4'-dicyclohexylmethane diisocyanate to dibutyltin dilaurate, stir and react at 75~85℃ for 2~3 h under nitrogen protection, quench the reaction with 0.2~0.3 times the molar amount of anhydrous ethanol to quench the reaction, and vacuum dry at 50~60℃ for 20~24 h to obtain polyurethane.

9. The preparation process of the weather-resistant polyurethane coating material according to claim 8, characterized in that, The polytetrahydrofuran diol has a molecular weight of 1000.

10. The preparation process of the weather-resistant polyurethane coating material according to claim 1, characterized in that, The preparation process of the polyurethane coating material in step S5 is as follows: 70-80 parts of polyurethane, 10-14 parts of high-efficiency flame retardant, and 6-7 parts of modified sericite are mixed, and the solid content is adjusted to 50%-60% with the solvent N,N-dimethylformamide to obtain a polyurethane coating; the polyurethane coating is poured into a mold and dried at 80-100℃ for 20-24 hours, and then naturally dried at room temperature for 24 hours to obtain a weather-resistant polyurethane coating material.

Images