A flame retardant and highly wear-resistant epoxy powder coating and its preparation method

Abstract

The present invention relates to a flame-retardant, highly wear-resistant epoxy powder coating and a preparation method thereof, belonging to the technical field of powder coatings. The raw materials of the flame-retardant, highly wear-resistant epoxy powder coating include a modified epoxy resin, a composite filler, a curing agent, an imidazole accelerator, a leveling agent, and an anti-caking agent. By modifying the epoxy resin, multi-scale compounding of the composite filler, and modifying the composite filler components, the wear resistance and flame retardancy of the coating are significantly improved, and the service life of the coating is extended.

Description

Technical Field

[0001] The invention belongs to the technical field of powder coatings and relates to a flame-retardant and highly wear-resistant epoxy powder coating and a preparation method thereof. Background Art

[0002] Powder coating is a solvent-free coating made from resins, pigments, fillers, and other additives in powder form. Unlike traditional liquid coatings, powder coating is applied evenly to surfaces through electrostatic spraying. It is then heated, melted, and solidified to form a durable coating. Powder coatings are widely used in a variety of applications, including automotive, home appliances, construction, and home furnishings, and are particularly important in the coating of automotive parts.

[0003] However, during the operation of the car, the parts are always in high-speed operation. Traditional powder coatings may not provide sufficient wear protection, and the wear of the coating will be accelerated, which will affect the service life and performance of the product. In addition, the operation of the car may expose some parts to high temperature environment, which requires powder coatings to have high flame retardant properties to prevent fire hazards. Summary of the Invention

[0004] The purpose of the present invention is to provide a flame-retardant and highly wear-resistant epoxy powder coating and a preparation method thereof. By modifying the epoxy resin, multi-scale composite of composite fillers, and modifying the components of the composite fillers, the wear resistance and flame retardancy of the coating are significantly improved, and the service life of the coating is extended.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A flame retardant and highly wear-resistant epoxy powder coating. The raw materials of the flame retardant and highly wear-resistant epoxy powder coating comprise, by weight, 70-90 parts of modified epoxy resin, 15-21 parts of composite filler, 4.5-5.5 parts of curing agent, 0.4-0.6 parts of imidazole accelerator, 1.5-2.5 parts of leveling agent and 0.8-1.2 parts of anti-caking agent.

[0007] Furthermore, the preparation method of the modified epoxy resin is:

[0008] A. Dissolve bisphenol A epoxy resin in anhydrous ethanol, stir and heat to 75-85°C, maintain the temperature and stir for 4-6 minutes, then add DOPO and polyetheramine, maintain the temperature and stir for 3-4 hours, and remove the anhydrous ethanol by rotary evaporation at 70°C to obtain a modified epoxy resin.

[0009] Furthermore, in step A, the mass ratio of the bisphenol A epoxy resin, anhydrous ethanol, DOPO and polyetheramine is 70-90:180-220:6-10:3-5.

[0010] Furthermore, the preparation method of the composite filler is:

[0011] B. Aluminum oxide, modified nano-silica and modified nano-montmorillonite were mixed and ball-milled in a ball mill at a speed of 300-400 rpm for 5.6-6.4 h. The mixture was passed through a 100 μm sieve to obtain a composite filler.

[0012] Furthermore, in step B, the mass ratio of the aluminum oxide, modified nano-silicon dioxide and modified nano-montmorillonite is 8.9-11.5:3.8-4.4:3.3-3.9; and the average particle size of the aluminum oxide is 1-5 μm.

[0013] Furthermore, the preparation method of the modified nano-silica in step B is:

[0014] C1. Add nano-silica to anhydrous ethanol, set the ultrasonic frequency and power to 20-40 kHz and 100-200 W, respectively, and ultrasonicate for 25-35 minutes. Then, add γ-aminopropyltriethoxysilane, stir at 200-400 rpm at 55-65°C for 1.5-2.5 hours, then wash with deionized water three times, and dry in an oven at 60°C to constant weight to obtain material 1;

[0015] C2. Add material 1 to Tris-HCl buffer with a pH of 8-9, stir at 250-350 rpm for 20-40 min, add dopamine hydrochloride, and stir at room temperature for 10-14 h. After stirring, wash with deionized water three times, and dry in an oven at 50°C to constant weight to obtain modified nano-silica.

[0016] Furthermore, the mass ratio of the nano-silica, anhydrous ethanol, and γ-aminopropyltriethoxysilane in step C1 is 3.8-4.2:95-105:0.3-0.5; the mass ratio of material 1, Tris-HCl buffer, and dopamine hydrochloride in step C2 is 3.5-4.5:100-110:2.8-3.2.

[0017] Furthermore, the preparation method of the modified nano-montmorillonite in step B is:

[0018] D. Add the nano-montmorillonite to deionized water, stir at 400-600 rpm for 20-40 min, add hexamethylenetetramine, stir at 75-85° C. for 2.8-3.4 h, and then centrifuge at 2800-3200 rpm for 8-12 min. Retain the precipitate, wash the precipitate three times with deionized water, and dry it in an oven at 60° C. to constant weight to obtain modified nano-montmorillonite.

[0019] Furthermore, the mass ratio of the nano-montmorillonite, deionized water, and hexamethylenetetramine in step D is 3.7-4.3:90-110:0.7-0.9.

[0020] Furthermore, the preparation method is:

[0021] Prepare the raw materials according to weight parts, mix the modified epoxy resin, composite filler, curing agent, imidazole accelerator and leveling agent in a high-speed mixer at a speed of 800-1200 rpm for 5-11 minutes to obtain a premix, put the premix into a twin-screw extruder, set the extrusion temperature of the extruder to 110-120°C, and the screw speed of the extruder to 200-300 rpm, cool to room temperature after extrusion to obtain an extrudate, crush the extrudate to 1-5 mm, add an anti-caking agent, and mix evenly to obtain a flame-retardant and highly wear-resistant epoxy powder coating.

[0022] Beneficial effects of the present invention:

[0023] (1) DOPO is added to the modified epoxy resin of the present invention. As a highly efficient phosphorus-containing flame retardant, DOPO can quickly form a stable carbonized layer when exposed to flames, which not only isolates oxygen and heat but also inhibits the release of harmful gases, thereby effectively slowing down the spread of flames. Polyetheramine contains a long-chain flexible molecular structure, which can improve the cross-linking density of the epoxy resin, improve the flexibility and crack resistance of the epoxy resin, and make the coating less likely to crack or fall off when subjected to mechanical stress such as temperature changes or high friction, thereby improving the durability of the coating.

[0024] (2) The composite filler of the present invention is obtained by compounding micron-sized aluminum oxide, modified nano-silica and modified nano-montmorillonite. The micropores and voids in the coating are effectively filled by the multi-scale filling effect, and the density of the coating is significantly improved. The aluminum oxide can effectively improve the wear resistance and mechanical strength of the coating due to its high hardness and good chemical stability. The nano-silica in the modified nano-silica is subjected to the action of γ-aminopropyltriethoxysilane, and the surface activity is enhanced, thereby improving the binding force between the nano-silica and the epoxy resin matrix. At the same time, dopamine hydrochloride undergoes an oxidative self-polymerization reaction in Tris-HCl buffer to form a layer of polydopamine coating on the surface of the nano-silica, so that the nano-silica can be more evenly dispersed in the epoxy resin matrix, avoiding filler agglomeration. In addition, the polydopamine coating is A carbonization reaction will occur under the condition of high temperature to generate a dense carbonized protective layer, which effectively blocks the transfer of oxygen and heat, thereby enhancing the flame retardant properties of the coating, thereby further improving the wear resistance and flame retardancy of the coating; the surface treatment of montmorillonite with hexamethylenetetramine significantly improves its dispersibility, interface reinforcement ability and flame retardancy in the epoxy resin matrix. The hexamethylenetetramine decomposes under high temperature conditions to form an expansive carbonized layer on the surface of the coating, and the layered structure of the montmorillonite itself can effectively prevent the diffusion of heat and combustion products, thereby improving the flame retardant properties of the coating. In addition, after the modified nano-montmorillonite is uniformly dispersed in the epoxy resin matrix, its high aspect ratio layered structure can significantly enhance the mechanical reinforcement effect of the coating, play a role in blocking crack propagation, thereby delaying the damage of the coating and extending the service life of the coating. DETAILED DESCRIPTION

[0025] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0026] The bisphenol A epoxy resin in all the embodiments and comparative examples of the present invention was purchased directly from the market and purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; DOPO was purchased directly from the market and purchased from Wuhan Huaxiang Kejie Biotechnology Co., Ltd.; polyetheramine was purchased directly from the market and purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; aluminum oxide was purchased directly from the market and purchased from Jining Tangyi Chemical Co., Ltd.; nano-silica was purchased directly from the market and purchased from Jiangsu Jingshengyuan New Material Technology Co., Ltd.; γ-aminopropyltriethoxysilane was purchased directly from the market and purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; Tris-HCl buffer was purchased directly from the market and purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd. Rich (Shanghai) Trading Co., Ltd.; dopamine hydrochloride was purchased directly from the market and purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; nano-montmorillonite was purchased directly from the market and purchased from Zhejiang Fenghong New Materials Co., Ltd.; hexamethylenetetramine was purchased directly from the market and purchased from Henan Chunqi Chemical Products Co., Ltd.; dicyandiamide was purchased directly from the market and purchased from Jinan Shanhai Chemical Technology Co., Ltd.; triglycidyl isocyanurate was purchased directly from the market and purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; 2-methylimidazole was purchased directly from the market and purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; silicon micropowder was purchased directly from the market and purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0027] Example 1

[0028] A flame-retardant and highly wear-resistant epoxy powder coating. The raw materials of the flame-retardant and highly wear-resistant epoxy powder coating of this embodiment include, by weight, 70 parts of modified epoxy resin, 15 parts of composite filler, 4.5 parts of curing agent, 0.4 parts of imidazole accelerator, 1.5 parts of leveling agent and 0.8 parts of anti-caking agent; wherein the curing agent, imidazole accelerator, leveling agent and anti-caking agent are dicyandiamide, triglycidyl isocyanurate, 2-methylimidazole and silica powder, respectively.

[0029] The preparation method of the modified epoxy resin of this embodiment is:

[0030] A. Dissolve bisphenol A epoxy resin in anhydrous ethanol, stir and heat to 75°C, keep the temperature constant and stir for 4 minutes, then add DOPO and polyetheramine, keep the temperature constant and stir for 3 hours, and remove the anhydrous ethanol by rotary evaporation at 70°C to obtain a modified epoxy resin.

[0031] The mass ratio of bisphenol A epoxy resin, anhydrous ethanol, DOPO and polyetheramine in step A of this embodiment is 70:180:6:3.

[0032] The preparation method of the composite filler of this embodiment is:

[0033] B. Aluminum oxide, modified nano-silica and modified nano-montmorillonite were mixed and ball-milled in a ball mill at a speed of 300 rpm for 5.6 h. The mixture was passed through a 100 μm sieve to obtain a composite filler.

[0034] The mass ratio of aluminum oxide, modified nano-silicon dioxide, and modified nano-montmorillonite in step B of this embodiment is 8.9:3.8:3.3; the average particle size of aluminum oxide is 1 μm.

[0035] The preparation method of the modified nano-silica in step B of this embodiment is:

[0036] C1. Add nano-silica to anhydrous ethanol, set the ultrasonic frequency and power to 20 kHz and 100 W respectively, after ultrasonication for 25 minutes, add γ-aminopropyltriethoxysilane, stir at 200 rpm at 55°C for 1.5 hours, then wash with deionized water three times, and dry in an oven at 60°C to constant weight to obtain material 1;

[0037] C2. Add material 1 into Tris-HCl buffer with a pH of 8, stir at 250 rpm for 20 min, add dopamine hydrochloride, and stir at room temperature for 10 h. After stirring, wash with deionized water three times and dry in an oven at 50°C to constant weight to obtain modified nano-silica.

[0038] In step C1 of this embodiment, the mass ratio of nano-silica, anhydrous ethanol, and γ-aminopropyltriethoxysilane is 3.8:95:0.3; the mass ratio of material 1, Tris-HCl buffer, and dopamine hydrochloride in step C2 is 3.5:100:2.8.

[0039] The preparation method of the modified nano-montmorillonite in step B of this embodiment is:

[0040] D. Add nano-montmorillonite to deionized water, stir at 400 rpm for 20 min, add hexamethylenetetramine, stir at 75°C for 2.8 h, and then centrifuge at 2800 rpm for 8 min. Retain the precipitate, wash the precipitate three times with deionized water, and dry it in an oven at 60°C to constant weight to obtain modified nano-montmorillonite.

[0041] The mass ratio of the nano-montmorillonite, deionized water, and hexamethylenetetramine in step D of this embodiment is 3.7:90:0.7.

[0042] The preparation method of this embodiment is:

[0043] Prepare the raw materials according to weight parts, mix the modified epoxy resin, composite filler, curing agent, imidazole accelerator and leveling agent in a high-speed mixer at a speed of 800 rpm for 5 minutes to obtain a premix, put the premix into a twin-screw extruder, set the extrusion temperature of the extruder to 110°C, and the screw speed of the extruder to 200 rpm. After extrusion, cool to room temperature to obtain an extrudate, crush the extrudate to 1 mm, add an anti-caking agent, and mix evenly to obtain a flame-retardant and highly wear-resistant epoxy powder coating.

[0044] Example 2

[0045] A flame-retardant and highly wear-resistant epoxy powder coating. The raw materials of the flame-retardant and highly wear-resistant epoxy powder coating of this embodiment include, by weight, 90 parts of modified epoxy resin, 21 parts of composite filler, 5.5 parts of curing agent, 0.6 parts of imidazole accelerator, 2.5 parts of leveling agent and 1.2 parts of anti-caking agent; wherein the curing agent, imidazole accelerator, leveling agent and anti-caking agent are dicyandiamide, triglycidyl isocyanurate, 2-methylimidazole and silicon powder, respectively.

[0046] The preparation method of the modified epoxy resin of this embodiment is:

[0047] A. Dissolve bisphenol A epoxy resin in anhydrous ethanol, stir and heat to 85°C, keep the temperature constant and stir for 6 minutes, then add DOPO and polyetheramine, keep the temperature constant and stir for 4 hours, and remove the anhydrous ethanol by rotary evaporation at 70°C to obtain a modified epoxy resin.

[0048] The mass ratio of bisphenol A epoxy resin, anhydrous ethanol, DOPO and polyetheramine in step A of this embodiment is 90:220:10:5.

[0049] The preparation method of the composite filler of this embodiment is:

[0050] B. Aluminum oxide, modified nano-silica and modified nano-montmorillonite were mixed and ball-milled in a ball mill at a speed of 400 rpm for 6.4 h. The mixture was passed through a 100 μm sieve to obtain a composite filler.

[0051] The mass ratio of aluminum oxide, modified nano-silica, and modified nano-montmorillonite in step B of this embodiment is 11.5:4.4:3.9; the average particle size of aluminum oxide is 5 μm.

[0052] The preparation method of the modified nano-silica in step B of this embodiment is:

[0053] C1. Add nano-silica to anhydrous ethanol, set the ultrasonic frequency and power to 40 kHz and 200 W respectively, after ultrasonication for 35 minutes, add γ-aminopropyltriethoxysilane, and stir at 400 rpm at 65°C for 2.5 hours. Then, wash with deionized water three times and dry in an oven at 60°C to constant weight to obtain material 1;

[0054] C2. Add material 1 into Tris-HCl buffer with a pH of 9, stir at 350 rpm for 40 min, add dopamine hydrochloride, stir at room temperature for 14 h, wash with deionized water three times after stirring, and dry in an oven at 50°C to constant weight to obtain modified nano-silica.

[0055] In this embodiment, the mass ratio of nano-silica, anhydrous ethanol, and γ-aminopropyltriethoxysilane in step C1 is 4.2:105:0.5; the mass ratio of material 1, Tris-HCl buffer, and dopamine hydrochloride in step C2 is 4.5:110:3.2.

[0056] The preparation method of the modified nano-montmorillonite in step B of this embodiment is:

[0057] D. Add nano-montmorillonite to deionized water, stir at 600 rpm for 40 min, add hexamethylenetetramine, stir at 85°C for 3.4 h, and then centrifuge at 3200 rpm for 12 min. Retain the precipitate, wash the precipitate three times with deionized water, and dry it in an oven at 60°C to constant weight to obtain modified nano-montmorillonite.

[0058] The mass ratio of the nano-montmorillonite, deionized water, and hexamethylenetetramine in step D of this embodiment is 4.3:110:0.9.

[0059] The preparation method of this embodiment is:

[0060] Prepare the raw materials according to weight parts, mix the modified epoxy resin, composite filler, curing agent, imidazole accelerator and leveling agent in a high-speed mixer at a speed of 1200 rpm for 11 minutes to obtain a premix, put the premix into a twin-screw extruder, set the extrusion temperature of the extruder to 120°C, and the screw speed of the extruder to 300 rpm. After extrusion, cool to room temperature to obtain an extrudate, crush the extrudate to 5 mm, add an anti-caking agent, and mix evenly to obtain a flame-retardant and highly wear-resistant epoxy powder coating.

[0061] Example 3

[0062] A flame-retardant and highly wear-resistant epoxy powder coating. The raw materials of the flame-retardant and highly wear-resistant epoxy powder coating of this embodiment include, by weight, 80 parts of modified epoxy resin, 18 parts of composite filler, 5 parts of curing agent, 0.5 parts of imidazole accelerator, 2 parts of leveling agent and 1 part of anti-caking agent; wherein the curing agent, imidazole accelerator, leveling agent and anti-caking agent are dicyandiamide, triglycidyl isocyanurate, 2-methylimidazole and silicon powder, respectively.

[0063] The preparation method of the modified epoxy resin of this embodiment is:

[0064] A. Dissolve bisphenol A epoxy resin in anhydrous ethanol, stir and heat to 80°C, keep the temperature constant and stir for 5 minutes, then add DOPO and polyetheramine, keep the temperature constant and stir for 3.5 hours, and remove the anhydrous ethanol by rotary evaporation at 70°C to obtain a modified epoxy resin.

[0065] The mass ratio of bisphenol A epoxy resin, anhydrous ethanol, DOPO and polyetheramine in step A of this embodiment is 80:200:8:4.

[0066] The preparation method of the composite filler of this embodiment is:

[0067] B. Aluminum oxide, modified nano-silica and modified nano-montmorillonite were mixed and ball-milled in a ball mill at a speed of 350 rpm for 6 h. The mixture was passed through a 100 μm sieve to obtain a composite filler.

[0068] The mass ratio of aluminum oxide, modified nano-silica, and modified nano-montmorillonite in step B of this embodiment is 10.2:4.1:3.6; the average particle size of aluminum oxide is 3 μm.

[0069] The preparation method of the modified nano-silica in step B of this embodiment is:

[0070] C1. Add nano-silica to anhydrous ethanol, set the ultrasonic frequency and power to 30 kHz and 150 W respectively, after ultrasonication for 30 minutes, add γ-aminopropyltriethoxysilane, and stir at 300 rpm at 60°C for 2 hours. Then, wash with deionized water three times and dry in an oven at 60°C to constant weight to obtain material 1;

[0071] C2. Add material 1 into Tris-HCl buffer with a pH of 8.5, stir at 300 rpm for 30 min, add dopamine hydrochloride, and stir at room temperature for 12 h. After stirring, wash with deionized water three times and dry in an oven at 50°C to constant weight to obtain modified nano-silica.

[0072] In this embodiment, the mass ratio of nano-silica, anhydrous ethanol, and γ-aminopropyltriethoxysilane in step C1 is 4:100:0.4; the mass ratio of material 1, Tris-HCl buffer, and dopamine hydrochloride in step C2 is 4:105:3.

[0073] The preparation method of the modified nano-montmorillonite in step B of this embodiment is:

[0074] D. Add nano-montmorillonite to deionized water, stir at 500 rpm for 30 min, add hexamethylenetetramine, stir at 80°C for 3.1 h, and then centrifuge at 3000 rpm for 10 min. Retain the precipitate, wash the precipitate three times with deionized water, and dry it in an oven at 60°C to constant weight to obtain modified nano-montmorillonite.

[0075] The mass ratio of the nano-montmorillonite, deionized water, and hexamethylenetetramine in step D of this embodiment is 4:100:0.8.

[0076] The preparation method of this embodiment is:

[0077] Prepare the raw materials according to weight parts, mix the modified epoxy resin, composite filler, curing agent, imidazole accelerator and leveling agent in a high-speed mixer at a speed of 1000 rpm for 8 minutes to obtain a premix, put the premix into a twin-screw extruder, set the extrusion temperature of the extruder to 115°C, and the screw speed of the extruder to 250 rpm. After extrusion, cool to room temperature to obtain an extrudate, crush the extrudate to 3 mm, add an anti-caking agent, and mix evenly to obtain a flame-retardant and highly wear-resistant epoxy powder coating.

[0078] Comparative Example 1

[0079] On the basis of Example 3, the modified epoxy resin was removed and replaced with an equal weight of bisphenol A epoxy resin. Other conditions were the same as those in Example 3.

[0080] Comparative Example 2

[0081] On the basis of Example 3, DOPO in the modified epoxy resin was removed and replaced with an equal weight of polyetheramine. Other conditions were the same as those in Example 3.

[0082] Comparative Example 3

[0083] On the basis of Example 3, the polyetheramine in the modified epoxy resin was removed and replaced with an equal weight of DOPO. Other conditions were the same as those in Example 3.

[0084] Comparative Example 4

[0085] On the basis of Example 3, the aluminum oxide in the composite filler was removed and replaced with an equal weight of modified nano-silicon dioxide. Other conditions were the same as those in Example 3.

[0086] Comparative Example 5

[0087] On the basis of Example 3, the modified nano-silica in the composite filler was removed and replaced with an equal weight of modified nano-montmorillonite. Other conditions were the same as those in Example 3.

[0088] Comparative Example 6

[0089] On the basis of Example 3, the modified nano-montmorillonite was removed and replaced with an equal weight of aluminum oxide. Other conditions were the same as those in Example 3.

[0090] Comparative Example 7

[0091] On the basis of Example 3, the average particle size of aluminum oxide was changed to 20 μm, and other conditions were the same as those in Example 3.

[0092] Comparative Example 8

[0093] On the basis of Example 3, keeping other conditions the same, the preparation method of modified nano-silica was changed to:

[0094] Nano-silica was added to anhydrous ethanol, and the ultrasonic frequency and power were set to 20 kHz and 100 W respectively. After ultrasonication for 25 minutes, γ-aminopropyltriethoxysilane was added, and the mixture was stirred at 200 rpm at 55°C for 1.5 hours. The mixture was then washed with deionized water three times and dried in an oven at 60°C to constant weight to obtain modified nano-silica.

[0095] Comparative Example 9

[0096] On the basis of Example 3, the modified nano-silica was removed and replaced with nano-silica of equal weight, and other conditions were consistent with Example 3.

[0097] Comparative Example 10

[0098] On the basis of Example 3, the modified nano-montmorillonite was removed and replaced with an equal weight of nano-montmorillonite, and other conditions were consistent with Example 3.

[0099] The epoxy powder coatings prepared in Examples 1-3 and Comparative Examples 1-10 were used as samples. The samples were sprayed on a substrate using electrostatic spraying technology. The spraying voltage was controlled at 70±0.5kV, the spraying thickness was 2mm, and the samples were cured in an oven at 180°C for 20 minutes. The performance was tested.

[0100] The wear resistance of the specimens was tested according to GB / T 1768-2006, using a 1kg / 1000r test and a CS-17 wheel. The total mass loss (mg) was used to determine the wear resistance. Five parallel tests were performed, and the average values ​​were recorded as shown in Table 1 below. The flame retardancy of the specimens was tested according to MT113-1995, using the flaming combustion time (s) as the test standard to determine the flame retardancy. Five parallel tests were performed, and the average values ​​were recorded as shown in Table 1 below.

[0101] Table 1 Performance test results

[0102]

[0103]

[0104] As can be seen from Table 1, the epoxy powder coatings prepared in Examples 1-3 of the present invention have high wear resistance and flame retardancy, and have good application prospects. However, in Comparative Examples 1-10, the modified epoxy resin and composite filler in the present invention are modified in preparation method or component composition, and the obtained wear resistance and flame retardancy are not as good as those of the present invention, indicating that the solution of the present invention has unique advantages.

[0105] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any indirect modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A flame retardant and highly wear-resistant epoxy powder coating, characterized by: The raw materials of the flame retardant and high wear-resistant epoxy powder coating include, by weight, 70-90 parts of modified epoxy resin, 15-21 parts of composite filler, 4.5-5.5 parts of curing agent, 0.4-0.6 parts of imidazole accelerator, 1.5-2.5 parts of leveling agent and 0.8-1.2 parts of anti-caking agent; The preparation method of the modified epoxy resin is: A. Dissolve bisphenol A epoxy resin in anhydrous ethanol, stir and heat to 75-85°C, maintain the temperature and stir for 4-6 minutes, then add DOPO and polyetheramine, maintain the temperature and stir for 3-4 hours, and remove the anhydrous ethanol by rotary evaporation at 70°C to obtain a modified epoxy resin; The preparation method of the composite filler is as follows: B. Aluminum oxide, modified nano-silica and modified nano-montmorillonite were mixed and ball-milled in a ball mill at a speed of 300-400 rpm for 5.6-6.4 h, and the mixture was passed through a 100 μm sieve to obtain a composite filler; The average particle size of the aluminum oxide is 1-5 μm; The preparation method of the modified nano-silica is: C1. Add nano-silica to anhydrous ethanol, set the ultrasonic frequency and power to 20-40 kHz and 100-200 W, respectively, and ultrasonicate for 25-35 minutes. Then, add γ-aminopropyltriethoxysilane, stir at 200-400 rpm at 55-65°C for 1.5-2.5 hours, then wash with deionized water three times, and dry in an oven at 60°C to constant weight to obtain material 1; C2, adding material 1 to Tris-HCl buffer with a pH of 8-9, stirring at 250-350 rpm for 20-40 min, adding dopamine hydrochloride, stirring at room temperature for 10-14 h, washing with deionized water three times after stirring, and drying in an oven at 50°C to constant weight to obtain modified nano-silica; The preparation method of the modified nano-montmorillonite is: D. Add the nano-montmorillonite to deionized water, stir at 400-600 rpm for 20-40 min, add hexamethylenetetramine, stir at 75-85° C. for 2.8-3.4 h, and then centrifuge at 2800-3200 rpm for 8-12 min. Retain the precipitate, wash the precipitate three times with deionized water, and dry it in an oven at 60° C. to constant weight to obtain modified nano-montmorillonite.

2. The flame retardant and highly wear-resistant epoxy powder coating according to claim 1, characterized in that: The mass ratio of the bisphenol A epoxy resin, anhydrous ethanol, DOPO and polyetheramine in step A is 70-90:180-220:6-10:3-5.

3. The flame retardant and highly wear-resistant epoxy powder coating according to claim 1, characterized in that: The mass ratio of the aluminum oxide, modified nano-silicon dioxide and modified nano-montmorillonite in step B is 8.9-11.5:3.8-4.4:3.3-3.

9.

4. The flame retardant and highly wear-resistant epoxy powder coating according to claim 1, characterized in that: The mass ratio of the nano-silica, anhydrous ethanol, and γ-aminopropyltriethoxysilane in step C1 is 3.8-4.2:95-105:0.3-0.5; the mass ratio of material 1, Tris-HCl buffer, and dopamine hydrochloride in step C2 is 3.5-4.5:100-110:2.8-3.

2.

5. The flame retardant and highly wear-resistant epoxy powder coating according to claim 1, characterized in that: The mass ratio of the nano-montmorillonite, deionized water and hexamethylenetetramine in step D is 3.7-4.3:90-110:0.7-0.

9.

6. A method for preparing the flame-retardant and highly wear-resistant epoxy powder coating according to any one of claims 1 to 5, characterized in that: The preparation method is: Prepare the raw materials according to weight parts, mix the modified epoxy resin, composite filler, curing agent, imidazole accelerator and leveling agent in a high-speed mixer at a speed of 800-1200 rpm for 5-11 minutes to obtain a premix, put the premix into a twin-screw extruder, set the extrusion temperature of the extruder to 110-120°C, and the screw speed of the extruder to 200-300 rpm, cool to room temperature after extrusion to obtain an extrudate, crush the extrudate to 1-5 mm, add an anti-caking agent, and mix evenly to obtain a flame-retardant and highly wear-resistant epoxy powder coating.

Images