High-weather-resistant flame-retardant powder coating and preparation method thereof

Abstract

The invention discloses a high-weather-resistance flame-retardant powder coating and a preparation method thereof, and belongs to the technical field of powder coatings. The preparation method comprises the following steps: adding epoxy resin, a flame retardant, a modified POSS (Polyhedral Oligomeric Silsesquioxane) material, titanium dioxide, adipic dihydrazide, 2-methylimidazole, a flatting agent and benzoin into a high-speed mixer, stirring at 1200-1500rpm for 5-8min, then extruding and granulating the mixed material through a double-screw extruder at the extrusion temperature of 100-120 DEG C and the screw rotating speed of 200-300rpm, grinding into powder with the particle size of 30-50 microns, and finally, carrying out extrusion granulation on the powder with the particle size of 30-50 microns. The high-weather-resistance flame-retardant powder coating is obtained. The powder coating disclosed by the invention has good weather resistance and flame retardance.

Description

Technical Field

[0001] This invention belongs to the field of powder coating technology, and more specifically, relates to a high weather-resistant and flame-retardant powder coating and its preparation method. Background Technology

[0002] Compared with traditional solvent-based coatings, powder coatings have the advantages of high utilization rate and safety and environmental protection, and are widely used in home appliances, building materials, transportation facilities, automotive parts and other fields. However, as people's requirements for coating performance continue to increase, the limitations of traditional powder coatings have begun to emerge. For example, ordinary powder coatings exposed to the outdoor environment for a long time are easily corroded by natural factors such as sunlight, rain, and ultraviolet radiation, which will lead to a decline in coating performance and affect the service life of the coated object. Therefore, how to avoid this phenomenon is the key to solving the problem. For example, patent application CN117820943A discloses an impact-resistant epoxy powder coating and its preparation method. The coating prepared by this impact-resistant epoxy powder coating and its preparation method has excellent impact resistance, wear resistance and hydrophobicity higher than similar products on the market. While ensuring wear resistance, its toughness and adhesion are also superior. The coupling effect between the modified filler and the resin material is excellent, which can make the filler have reliable molecular structure force in the finished product. Combined with the hardness characteristics of the filler itself, the impact resistance of the epoxy powder coating can be fully utilized. However, the weather resistance needs to be improved. Summary of the Invention

[0003] Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a high weather-resistant and flame-retardant powder coating and its preparation method. The powder coating of this invention has excellent weather resistance and flame-retardant properties.

[0004] Technical solution To solve the above problems, the technical solution adopted by the present invention is as follows: The present invention discloses a method for preparing a high weather-resistant and flame-retardant powder coating, which includes the following steps: (1) Preparation of flame retardants; (2) Preparation of modified POSS materials; (3) Add epoxy resin, flame retardant, modified POSS material, titanium dioxide, adipic acid dihydrazide, 2-methylimidazole, leveling agent and benzoin to a high-speed mixer and stir at 1200-1500 rpm for 5-8 min. Then, extrude and granulate the mixed material through a twin-screw extruder at an extrusion temperature of 100-120℃ and a screw speed of 200-300 rpm. Grind the material into powder with a particle size of 30-50 μm to obtain a high weather-resistant flame-retardant powder coating.

[0005] Furthermore, in step (1), the method for preparing the flame retardant is as follows: Step 1: Under nitrogen protection, add 5-hydroxymethylfurfural and triethylamine to dichloromethane solvent, mix well, and then slowly add phenyl dichloride phosphate dropwise at 0-5℃. After the addition is complete, maintain the reaction at 0-5℃ for 3-5 hours, and then continue the reaction at 45-55℃ for 3-5 hours. After the reaction is completed, filter, wash and dry to obtain intermediate 1. Step 2: Add intermediate 1,2-aminophenyltriazole to acetonitrile solvent, stir and mix, then add anhydrous potassium carbonate, reflux at 60-80℃ for 8-12 hours. After the reaction is complete, filter, wash and dry to obtain flame retardant.

[0006] Furthermore, in step one, the mass ratio of dichloromethane, 5-hydroxymethylfurfural, triethylamine, and phenyl dichloride phosphate is 30-35 mL: 5.96-6 g: 4.84-4.88 g: 4.95-5 g.

[0007] Furthermore, in step two, the mass ratio of acetonitrile, intermediate 1,2-aminophenyltriazole, and anhydrous potassium carbonate is 30-40 mL: 3.95-4 g: 4.05-4.1 g: 2.5-2.6 g.

[0008] Furthermore, in step (2), the method for preparing the modified POSS material is as follows: S1: Deionized water, propanol, acetonitrile, and tetraethylammonium hydroxide are added sequentially to the reactor and mixed evenly. Then, γ-aminopropyltriethoxysilane is slowly added dropwise to the system and stirred at 45-55℃ for 22-26 hours. After the reaction is completed, the solvent is removed by rotary evaporation, water and cyclohexane are added for washing, and the mixture is freeze-dried to obtain the POSS material. S2: Add 2-aminobenzophenone and N,N'-carbonyldiimidazole to dimethyl sulfoxide solvent, mix well, stir and react at 75-85℃ for 2-3h. After the reaction is completed, cool to room temperature, wash with diethyl ether, precipitate, and vacuum dry to obtain intermediate 2. S3: Under nitrogen protection, POSS material is added to dimethyl sulfoxide solvent and ultrasonically treated for 15-20 min. Then intermediate 2 is added and the mixture is stirred at 35-45℃ for 14-18 h. After the reaction is completed, the mixture is centrifuged, washed and dried to obtain modified POSS material.

[0009] In the above steps, 2-aminobenzophenone reacts with N,N'-carbonyldiimidazole. The amino group on 2-aminobenzophenone nucleophilically attacks a carbonyl carbon on N,N'-carbonyldiimidazole, causing an imidazole molecule to leave and generating intermediate 2. Subsequently, the amino group on the POSS material nucleophilically attacks the carbonyl carbon on intermediate 2, releasing a second imidazole molecule and successfully grafting 2-aminobenzophenone onto the POSS material, thus obtaining the modified POSS material.

[0010] Furthermore, the mass ratio of deionized water, propanol, acetonitrile, tetraethylammonium hydroxide, and γ-aminopropyltriethoxysilane in S1 is 22-23 mL: 9.8-10 mL: 2.45-2.5 mL: 0.5-0.6 mL: 53-54 g.

[0011] Furthermore, the mass ratio of dimethyl sulfoxide, 2-aminobenzophenone, and N,N'-carbonyldiimidazole in S2 is 65-70 mL: 2.62-2.66 g: 2.98-3.02 g.

[0012] Furthermore, the mass ratio of dimethyl sulfoxide, POSS material, and intermediate 2 in S3 is 100-120mL:1.38-1.42g:1.5-1.6g.

[0013] Further, in step (3), the weight parts of each component are: 50-60 parts of epoxy resin, 6-8 parts of flame retardant, 3-5 parts of modified POSS material, 10-12 parts of titanium dioxide, 2-4 parts of adipic acid dihydrazide, 0.4-0.6 parts of 2-methylimidazole, 1-2 parts of leveling agent, and 0.3-0.5 parts of benzoin.

[0014] This invention also protects a high weather-resistant and flame-retardant powder coating, which is prepared by any of the preparation methods described above.

[0015] Beneficial technical effects Compared with the prior art, the beneficial effects of the present invention are as follows: (1) 5-hydroxymethylfurfural and phenyl phosphate dichloride were reacted to obtain intermediate 1, which was then reacted with 2-aminobenzotriazole to obtain a flame retardant, thus constructing a phosphorus-nitrogen synergistic flame retardant system. Phosphorus can promote charring of the coating during combustion, forming a heat-insulating and oxygen-barrier char layer. Nitrogen can decompose and release non-flammable gases when heated, playing a gas-phase flame retardant role. The synergistic effect of phosphorus and nitrogen can improve the flame retardant performance of powder coatings. In addition, 2-aminobenzotriazole itself is also a UV absorber. While serving as a nitrogen source for the flame retardant, it also contributes to the coating's UV aging resistance. As a highly efficient UV absorber, ketones can be grafted onto POSS materials to firmly fix them in the coating system, allowing them to absorb UV rays for a long time. This avoids the problem of easy migration of small molecule additives, enhances the weather resistance of powder coatings, and ensures the long-term effectiveness of weather resistance. The stable silicon-oxygen structure in POSS materials is also highly weather-resistant and can achieve a synergistic weather resistance mechanism with 2-aminobenzophenone. Furthermore, POSS materials undergo ceramization during combustion, migrating to the coating surface to form a robust silica ceramic barrier. This physical barrier can further consolidate the flame-retardant properties of powder coatings.

[0016] (2) The high weather-resistant and flame-retardant powder coating of the present invention is obtained by the preparation method of the present invention and has all the beneficial effects of the preparation method of the present invention. Attached Figure Description

[0017] Figure 1 It is the synthesis reaction formula for flame retardants. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0019] To better understand the above technical solutions, the following will provide a detailed description of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0020] The reagents used in the following specific embodiments are of analytical grade. Additionally: Epoxy resin: Grade E51, industrial grade, manufactured by Nantong Xingchen Synthetic Materials Co., Ltd. Titanium dioxide: Grade R-706, rutile type, manufactured by Shanghai Changqi Chemical Co., Ltd. Leveling agent: GLP-588, manufactured by Ningbo Nanhai Chemical Co., Ltd.

[0021] Example 1 This embodiment provides a high weather-resistant and flame-retardant powder coating, the preparation method of which specifically includes the following steps: (1) Under nitrogen protection, 5.96 g of 5-hydroxymethylfurfural and 4.84 g of triethylamine were added to 30 mL of dichloromethane solvent and mixed evenly. Then, 4.95 g of phenyl dichloride phosphate was slowly added dropwise at 0 °C. After the addition was completed, the reaction was maintained at 0 °C for 3 h, and then the reaction was continued at 45 °C for 3 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain intermediate 1. (2) Add 3.95g of intermediate 1 and 4.05g of 2-aminophenyltriazole to 30mL of acetonitrile solvent, stir and mix, then add 2.5g of anhydrous potassium carbonate, reflux at 60-80℃ for 8-12h, filter, wash and dry to obtain flame retardant. (3) Add 22 mL of deionized water, 9.8 mL of propanol, 2.45 mL of acetonitrile and 0.5 mL of tetraethylammonium hydroxide to the reactor in sequence, mix well, and then slowly add 53 g of γ-aminopropyltriethoxysilane to the system. Stir at 45 °C for 22 h. After the reaction is completed, remove the solvent by rotary evaporation, add water and cyclohexane to wash, and freeze dry to obtain POSS material; (4) Add 2.62 g of 2-aminobenzophenone and 2.98 g of N,N'-carbonyldiimidazole to 65 mL of dimethyl sulfoxide solvent, mix well, stir at 75 °C for 2 h, after the reaction is completed, cool to room temperature, wash with diethyl ether, precipitate, and vacuum dry to obtain intermediate 2; (5) Under nitrogen protection, 1.38 g of POSS material was added to 100 mL of dimethyl sulfoxide solvent, ultrasonically treated for 15 min, and then 1.5 g of intermediate 2 was added. The mixture was stirred at 35 °C for 14 h. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain the modified POSS material. (6) 50 parts by weight of epoxy resin, 6 parts by weight of flame retardant, 3 parts by weight of modified POSS material, 10 parts by weight of titanium dioxide, 2 parts by weight of adipic acid dihydrazide, 0.4 parts by weight of 2-methylimidazole, 1 part by weight of leveling agent and 0.3 parts by weight of benzoin are added to a high-speed mixer and stirred at 1200 rpm for 5 min. The mixed material is then extruded and granulated through a twin-screw extruder at an extrusion temperature of 100℃ and a screw speed of 200 rpm. The mixture is then ground into powder with a particle size of 30 μm to obtain a high weather-resistant flame-retardant powder coating.

[0022] Example 2 This embodiment provides a high weather-resistant and flame-retardant powder coating, the preparation method of which specifically includes the following steps: (1) Under nitrogen protection, 6g of 5-hydroxymethylfurfural and 4.88g of triethylamine were added to 35mL of dichloromethane solvent and mixed evenly. Then, 5g of phenyl dichloride phosphate was slowly added dropwise at 5℃. After the addition was completed, the reaction was maintained at 5℃ for 5h and then continued at 55℃ for 5h. After the reaction was completed, the mixture was filtered, washed and dried to obtain intermediate 1. (2) Add 4g of intermediate 1 and 4.1g of 2-aminophenyltriazole to 40mL of acetonitrile solvent, stir and mix, then add 2.6g of anhydrous potassium carbonate, reflux at 80℃ for 12h, after the reaction is completed, filter, wash and dry to obtain flame retardant. (3) Add 23 mL of deionized water, 10 mL of propanol, 2.5 mL of acetonitrile and 0.6 mL of tetraethylammonium hydroxide to the reactor in sequence, mix well, and then slowly add 54 g of γ-aminopropyltriethoxysilane to the system. Stir at 55 °C for 26 h. After the reaction is completed, remove the solvent by rotary evaporation, add water and cyclohexane to wash, and freeze dry to obtain POSS material; (4) Add 2.66 g of 2-aminobenzophenone and 3.02 g of N,N'-carbonyldiimidazole to 70 mL of dimethyl sulfoxide solvent, mix well, stir at 85 °C for 3 h, after the reaction is completed, cool to room temperature, wash with diethyl ether, precipitate, and vacuum dry to obtain intermediate 2; (5) Under nitrogen protection, 1.42 g of POSS material was added to 120 mL of dimethyl sulfoxide solvent, and ultrasonic treatment was performed for 20 min. Then, 1.6 g of intermediate 2 was added, and the mixture was stirred at 45 °C for 18 h. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain the modified POSS material. (6) 60 parts by weight of epoxy resin, 8 parts by weight of flame retardant, 5 parts by weight of modified POSS material, 12 parts by weight of titanium dioxide, 4 parts by weight of adipic acid dihydrazide, 0.6 parts by weight of 2-methylimidazole, 2 parts by weight of leveling agent and 0.5 parts by weight of benzoin are added to a high-speed mixer and stirred at 1500 rpm for 8 min. The mixed material is then extruded and granulated through a twin-screw extruder at an extrusion temperature of 120°C and a screw speed of 300 rpm. The mixture is then ground into powder with a particle size of 50 μm to obtain a high weather-resistant flame-retardant powder coating.

[0023] Example 3 This embodiment provides a high weather-resistant and flame-retardant powder coating, the preparation method of which specifically includes the following steps: (1) Under nitrogen protection, 5.98 g of 5-hydroxymethylfurfural and 4.86 g of triethylamine were added to 33 mL of dichloromethane solvent and mixed evenly. Then, 4.98 g of phenyl dichloride phosphate was slowly added dropwise at 2 °C. After the addition was completed, the reaction was maintained at 2 °C for 4 h and then continued at 50 °C for 4 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain intermediate 1. (2) Add 3.98g of intermediate 1 and 4.08g of 2-aminophenyltriazole to 35mL of acetonitrile solvent, stir and mix, then add 2.55g of anhydrous potassium carbonate, reflux at 70℃ for 10h, filter, wash and dry to obtain flame retardant. (3) Add 22.5 mL of deionized water, 9.9 mL of propanol, 2.48 mL of acetonitrile and 0.55 mL of tetraethylammonium hydroxide to the reactor in sequence, mix well, and then slowly add 53.5 g of γ-aminopropyltriethoxysilane to the system. Stir at 50 °C for 24 h. After the reaction is completed, remove the solvent by rotary evaporation, add water and cyclohexane to wash, and freeze dry to obtain POSS material; (4) Add 2.64 g of 2-aminobenzophenone and 3 g of N,N'-carbonyldiimidazole to 68 mL of dimethyl sulfoxide solvent, mix well, stir at 80 °C for 2 h, after the reaction is completed, cool to room temperature, wash with diethyl ether, precipitate, and vacuum dry to obtain intermediate 2; (5) Under nitrogen protection, 1.4 g of POSS material was added to 110 mL of dimethyl sulfoxide solvent, sonicated for 18 min, and then 1.55 g of intermediate 2 was added. The mixture was stirred at 40 °C for 16 h. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain the modified POSS material. (6) 55 parts by weight of epoxy resin, 7 parts by weight of flame retardant, 4 parts by weight of modified POSS material, 11 parts by weight of titanium dioxide, 3 parts by weight of adipic acid dihydrazide, 0.5 parts by weight of 2-methylimidazole, 1.5 parts by weight of leveling agent and 0.4 parts by weight of benzoin are added to a high-speed mixer and stirred at 1300 rpm for 7 min. The mixed material is then extruded and granulated through a twin-screw extruder at an extrusion temperature of 110°C and a screw speed of 250 rpm. The mixture is then ground into powder with a particle size of 40 μm to obtain a high weather-resistant flame-retardant powder coating.

[0024] Example 4 This embodiment provides a high weather-resistant and flame-retardant powder coating, the preparation method of which specifically includes the following steps: (1) Under nitrogen protection, 5.97 g of 5-hydroxymethylfurfural and 4.85 g of triethylamine were added to 31 mL of dichloromethane solvent and mixed evenly. Then, 4.96 g of phenyl dichloride phosphate was slowly added dropwise at 1 °C. After the addition was completed, the reaction was maintained at 1 °C for 3 h and then continued at 48 °C for 3 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain intermediate 1. (2) Add 3.96g of intermediate 1 and 4.06g of 2-aminophenyltriazole to 32mL of acetonitrile solvent, stir and mix, then add 2.52g of anhydrous potassium carbonate, reflux at 65℃ for 9h, filter, wash and dry to obtain flame retardant; (3) Add 22 mL of deionized water, 9.85 mL of propanol, 2.46 mL of acetonitrile and 0.52 mL of tetraethylammonium hydroxide to the reactor in sequence, mix well, and then slowly add 53.2 g of γ-aminopropyltriethoxysilane to the system. Stir at 48 °C for 23 h. After the reaction is completed, remove the solvent by rotary evaporation, add water and cyclohexane to wash, and freeze dry to obtain POSS material; (4) Add 2.63 g of 2-aminobenzophenone and 2.99 g of N,N'-carbonyldiimidazole to 66 mL of dimethyl sulfoxide solvent, mix well, stir at 78 °C for 2 h, after the reaction is completed, cool to room temperature, wash with diethyl ether, precipitate, and vacuum dry to obtain intermediate 2; (5) Under nitrogen protection, 1.39 g of POSS material was added to 105 mL of dimethyl sulfoxide solvent, sonicated for 16 min, and then 1.52 g of intermediate 2 was added. The mixture was stirred at 38 °C for 15 h. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain the modified POSS material. (6) 52 parts by weight of epoxy resin, 6 parts by weight of flame retardant, 3 parts by weight of modified POSS material, 10 parts by weight of titanium dioxide, 3 parts by weight of adipic acid dihydrazide, 0.4 parts by weight of 2-methylimidazole, 1 part by weight of leveling agent and 0.4 parts by weight of benzoin are added to a high-speed mixer and stirred at 1300 rpm for 6 min. The mixed material is then extruded and granulated through a twin-screw extruder at an extrusion temperature of 105℃ and a screw speed of 210 rpm. The mixture is then ground into powder with a particle size of 35 μm to obtain a high weather-resistant flame-retardant powder coating.

[0025] Example 5 This embodiment provides a high weather-resistant and flame-retardant powder coating, the preparation method of which specifically includes the following steps: (1) Under nitrogen protection, 5.99 g of 5-hydroxymethylfurfural and 4.87 g of triethylamine were added to 34 mL of dichloromethane solvent and mixed evenly. Then, 4.99 g of phenyl dichloride phosphate was slowly added dropwise at 4 °C. After the addition was completed, the reaction was maintained at 4 °C for 5 h and then continued at 52 °C for 5 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain intermediate 1. (2) Add 3.99 g of intermediate 1 and 4.08 g of 2-aminophenyltriazole to 38 mL of acetonitrile solvent, stir and mix, then add 2.58 g of anhydrous potassium carbonate, reflux at 75 °C for 11 h, after the reaction is completed, filter, wash and dry to obtain flame retardant. (3) Add 23 mL of deionized water, 9.95 mL of propanol, 2.5 mL of acetonitrile and 0.58 mL of tetraethylammonium hydroxide to the reactor in sequence, mix well, and then slowly add 53.8 g of γ-aminopropyltriethoxysilane to the system. Stir at 52 °C for 25 h. After the reaction is completed, remove the solvent by rotary evaporation, add water and cyclohexane to wash, and freeze dry to obtain POSS material; (4) Add 2.65 g of 2-aminobenzophenone and 3.01 g of N,N'-carbonyldiimidazole to 69 mL of dimethyl sulfoxide solvent, mix well, stir at 82 °C for 3 h, after the reaction is completed, cool to room temperature, wash with diethyl ether, precipitate, and vacuum dry to obtain intermediate 2. (5) Under nitrogen protection, 1.41 g of POSS material was added to 115 mL of dimethyl sulfoxide solvent, sonicated for 19 min, and then 1.58 g of intermediate 2 was added. The mixture was stirred at 42 °C for 17 h. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain the modified POSS material. (6) 58 parts by weight of epoxy resin, 8 parts by weight of flame retardant, 4 parts by weight of modified POSS material, 11 parts by weight of titanium dioxide, 4 parts by weight of adipic acid dihydrazide, 0.6 parts by weight of 2-methylimidazole, 2 parts by weight of leveling agent and 0.5 parts by weight of benzoin are added to a high-speed mixer and stirred at 1400 rpm for 7 min. The mixed material is then extruded and granulated through a twin-screw extruder at an extrusion temperature of 115℃ and a screw speed of 280 rpm. The mixture is then ground into powder with a particle size of 45 μm to obtain a high weather-resistant flame-retardant powder coating.

[0026] Comparative Example 1 The formulation of the high weather-resistant and flame-retardant powder coating in Comparative Example 1 is basically the same as that in Example 1. The main difference is that intermediate 1 is used instead of flame retardant.

[0027] Comparative Example 2 The formulation of the high weather-resistant and flame-retardant powder coating in Comparative Example 2 is basically the same as that in Example 1. The main difference is that POSS material is used instead of modified POSS material.

[0028] Performance testing (1) Coating preparation: Seven tinplates with a size of 100mm×100mm×5mm were used as substrates. The powder coatings prepared in Examples 1-5 and Comparative Examples 1-2 were uniformly sprayed onto the substrate surface using an electrostatic spray gun. The final thickness of the dried composite coating was controlled to reach 0.5mm±0.001mm by a film thickness gauge. Then the sample was placed in a forced-air drying oven and baked at 180℃ for 15 minutes. After that, it was naturally cooled to room temperature to obtain a standard sample.

[0029] (2) The adhesion of the standard sample was tested according to GB / T9286; the UV aging resistance of the standard sample was tested according to ISO7724; and the flame retardant performance of the standard sample was tested by preparing it to the required standard size according to UL-94 standard. The test results are shown in Table 1.

[0030] Table 1: Performance Tests project Adhesion Resistance to UV aging (1000h, ΔE) Flame retardant rating Example 1 Level 0 2.4 V-0 Example 2 Level 0 2.1 V-0 Example 3 Level 0 2.3 V-0 Example 4 Level 0 2.3 V-0 Example 5 Level 0 2.2 V-0 Comparative Example 1 Level 1 2.9 V-1 Comparative Example 2 Level 0 3.8 V-0 As can be seen from Table 1, the powder coatings prepared in Examples 1-5 and Comparative Examples 1-2 have good adhesion, weather resistance and flame retardant properties.

[0031] The comparison shows that Comparative Example 1 uses intermediate 1 instead of flame retardant, lacking the nitrogen heterocyclic structure introduced after the reaction of 2-aminobenzotriazole. The small molecule intermediate 1 will migrate, resulting in a decrease in coating cohesion. Furthermore, benzotriazole also acts as a nitrogen source in both the UV absorber and the flame retardant. Therefore, the performance of Comparative Example 1 is lower than that of the examples. Comparative Example 2 uses POSS material instead of modified POSS material, lacking the grafting modification of 2-aminobenzophenone. 2-aminobenzophenone has a high UV absorption capacity, but due to the good compatibility and reactivity between the aminopropyl group of POSS material and epoxy resin, the basic adhesion is not affected. Moreover, thanks to the inherent physical shielding effect of the flame retardant and the nanocage of POSS material itself, the flame retardant effect can also reach the V-0 level. Therefore, the performance of Comparative Example 2 only shows a significant decrease in UV aging resistance.

[0032] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0033] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0034] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A method for preparing a high weather-resistant and flame-retardant powder coating, characterized in that, Includes the following steps: (1) Preparation of flame retardants; (2) Preparation of modified POSS materials; (3) Add epoxy resin, flame retardant, modified POSS material, titanium dioxide, adipic acid dihydrazide, 2-methylimidazole, leveling agent and benzoin to a high-speed mixer and stir at 1200-1500 rpm for 5-8 min. Then, extrude and granulate the mixed material through a twin-screw extruder at an extrusion temperature of 100-120℃ and a screw speed of 200-300 rpm. Grind the material into powder with a particle size of 30-50 μm to obtain a high weather-resistant flame-retardant powder coating.

2. The method for preparing high weather-resistant and flame-retardant powder coating according to claim 1, characterized in that, In step (1), the flame retardant is prepared by the following method: Step 1: Under nitrogen protection, add 5-hydroxymethylfurfural and triethylamine to dichloromethane solvent, mix well, and then slowly add phenyl dichloride phosphate dropwise at 0-5℃. After the addition is complete, maintain the reaction at 0-5℃ for 3-5 hours, and then continue the reaction at 45-55℃ for 3-5 hours. After the reaction is completed, filter, wash and dry to obtain intermediate 1. Step 2: Add intermediate 1,2-aminophenyltriazole to acetonitrile solvent, stir and mix, then add anhydrous potassium carbonate, reflux at 60-80℃ for 8-12 hours. After the reaction is complete, filter, wash and dry to obtain flame retardant.

3. The method for preparing high weather-resistant and flame-retardant powder coating according to claim 2, characterized in that, In step one, the mass ratio of dichloromethane, 5-hydroxymethylfurfural, triethylamine, and phenyl dichloride phosphate is 30-35 mL: 5.96-6 g: 4.84-4.88 g: 4.95-5 g.

4. The method for preparing high weather-resistant and flame-retardant powder coating according to claim 2, characterized in that, In step two, the mass ratio of acetonitrile, intermediate 1,2-aminophenyltriazole, and anhydrous potassium carbonate is 30-40 mL: 3.95-4 g: 4.05-4.1 g: 2.5-2.6 g.

5. The method for preparing high weather-resistant and flame-retardant powder coating according to claim 1, characterized in that, In step (2), the method for preparing the modified POSS material is as follows: S1: Deionized water, propanol, acetonitrile, and tetraethylammonium hydroxide are added sequentially to the reactor and mixed evenly. Then, γ-aminopropyltriethoxysilane is slowly added dropwise to the system and stirred at 45-55℃ for 22-26 hours. After the reaction is completed, the solvent is removed by rotary evaporation, water and cyclohexane are added for washing, and the mixture is freeze-dried to obtain the POSS material. S2: Add 2-aminobenzophenone and N,N'-carbonyldiimidazole to dimethyl sulfoxide solvent, mix well, stir and react at 75-85℃ for 2-3h. After the reaction is completed, cool to room temperature, wash with diethyl ether, precipitate, and vacuum dry to obtain intermediate 2. S3: Under nitrogen protection, POSS material is added to dimethyl sulfoxide solvent and ultrasonically treated for 15-20 min. Then intermediate 2 is added and the mixture is stirred at 35-45℃ for 14-18 h. After the reaction is completed, the mixture is centrifuged, washed and dried to obtain modified POSS material.

6. The method for preparing high weather-resistant and flame-retardant powder coating according to claim 5, characterized in that, The mass ratio of deionized water, propanol, acetonitrile, tetraethylammonium hydroxide, and γ-aminopropyltriethoxysilane in S1 is 22-23 mL: 9.8-10 mL: 2.45-2.5 mL: 0.5-0.6 mL: 53-54 g.

7. The method for preparing high weather-resistant and flame-retardant powder coating according to claim 5, characterized in that, The mass ratio of dimethyl sulfoxide, 2-aminobenzophenone, and N,N'-carbonyldiimidazole in S2 is 65-70 mL: 2.62-2.66 g: 2.98-3.02 g.

8. The method for preparing high weather-resistant and flame-retardant powder coating according to claim 5, characterized in that, The mass ratio of dimethyl sulfoxide, POSS material, and intermediate 2 in S3 is 100-120mL:1.38-1.42g:1.5-1.6g.

9. The method for preparing high weather-resistant and flame-retardant powder coating according to claim 1, characterized in that, In step (3), the weight parts of each component are as follows: 50-60 parts of epoxy resin, 6-8 parts of flame retardant, 3-5 parts of modified POSS material, 10-12 parts of titanium dioxide, 2-4 parts of adipic acid dihydrazide, 0.4-0.6 parts of 2-methylimidazole, 1-2 parts of leveling agent, and 0.3-0.5 parts of benzoin.

10. A high weather-resistant and flame-retardant powder coating, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.

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