A high-hardness and high-temperature resistant powder coating and its preparation method

Abstract

The present invention relates to a high-hardness, high-temperature resistant powder coating and a preparation method thereof, and belongs to the technical field of powder coatings. A high-hardness, high-temperature resistant powder coating comprises the following components: modified acrylic resin, epoxy resin, modified filler, titanium dioxide, curing agent and dispersant; the preparation method comprises the following steps: mixing the modified acrylic resin, epoxy resin and modified filler, placing them in a twin-screw extruder for melt extrusion, granulating, adding titanium dioxide, curing agent and dispersant, extruding granulation, crushing, and screening to obtain. The powder coating prepared by the present invention has excellent high-temperature resistance and mechanical strength after being cured into a paint film.

Description

Technical Field

[0001] The invention belongs to the technical field of powder coatings and relates to a high-hardness and high-temperature resistant powder coating and a preparation method thereof. Background Art

[0002] Powder coating is a solid coating that does not contain organic solvents, has excellent performance and is almost pollution-free to the environment. It is warmly welcomed by the market for its environmentally friendly characteristics, simple use methods and reasonable prices. In recent years, the sales share of powder coatings in the coatings industry has continued to grow. With the continuous research and development of powder coating products, its unique environmental protection, safety, high utilization rate and excellent performance advantages indicate that it will gradually replace traditional liquid coatings.

[0003] Graphene is known for its excellent mechanical, thermal and electrical conductivity, and has the property of being bendable. Therefore, when graphene is combined with an organic polymer system, the resulting graphene-enhanced polymer composite exhibits excellent thermal stability and strength. However, due to the extremely high surface energy of graphene, the dispersion of graphene in the organic polymer system is poor. This uneven dispersion problem in turn affects the thermal stability and mechanical strength of the graphene-enhanced organic polymer composite. Summary of the invention

[0004] The object of the present invention is to provide a high-hardness, high-temperature resistant powder coating and a preparation method thereof. The present invention forms a graphene film on the surface of barium sulfate as a composite filler for the powder coating, and then modifies the graphene / barium sulfate filler by vinyl salicylaldehyde and diaminophenol, and grafts DOPO with significant thermal stability, thereby improving the high-temperature resistance and mechanical properties of the paint film.

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

[0006] A high-hardness and high-temperature resistant powder coating comprises the following components by weight: 62-70 parts of modified acrylic resin, 60-64 parts of epoxy resin, 25-28 parts of modified filler, 1.4-2.0 parts of titanium dioxide, 4-6 parts of curing agent and 2-4 parts of dispersant; the curing agent is an amine curing agent.

[0007] As a preferred technical solution of the present invention, the curing agent is meta-xylylenediamine; and the dispersant is PE wax.

[0008] As a preferred technical solution of the present invention, the epoxy resin is one or both of bisphenol F epoxy resin and bisphenol A epoxy resin.

[0009] As a preferred technical solution of the present invention, the modified acrylic resin is a copolymerization product of glycidyl methacrylate, butyl methacrylate, methacrylic acid and styrene in a mass ratio of 1:2:1:1.

[0010] As a preferred technical solution of the present invention, the preparation method of the modified filler comprises the following steps:

[0011] 1) Under a nitrogen atmosphere, barium sulfate is placed in a microwave generator to increase pressure and temperature, and a reaction gas is introduced to perform vapor deposition to obtain a composite powder;

[0012] 2) placing the composite powder, vinyl salicylaldehyde and isobutyl alcohol in a reaction kettle, mixing and stirring, adding diaminophenol, heating and mixing, centrifuging to remove the solvent, washing with anhydrous ethanol, and vacuum drying to obtain an intermediate;

[0013] 3) Anhydrous ethanol and DOPO are mixed and stirred, and after preheating, an initiator and an intermediate are added, heated and stirred, the solvent is filtered out, and vacuum dried to obtain a modified filler.

[0014] As a preferred technical solution of the present invention, in step 1), the pressurization and heating is to heat the temperature to 730-750°C under a pressure environment of 5.5-6.0 kPa; the reaction gas is a mixed gas composed of methane and hydrogen in a volume ratio of 8.5:1.5, and the flow rate of the reaction gas is 0.3-0.4 L / min; the amount ratio of barium sulfate to reaction gas is 4.8-5.2 g:20-25 L.

[0015] As a preferred technical solution of the present invention, in step 2), the heating and mixing is heating at a temperature of 50-60°C for 5-6h; the washing is performed 3 times; the vacuum drying is vacuum drying at a temperature of 80°C to constant weight; the diaminophenol is 3,4-diaminophenol; and the mass ratio of the composite powder, vinyl salicylaldehyde, diaminophenol and isobutanol is 10-11:1.8-2.2:1.0-1.2:20-25.

[0016] As a preferred technical solution of the present invention, in step 3), the mass ratio of DOPO, initiator, intermediate and anhydrous ethanol is 2.0-2.3:0.09-0.11:15-16:30-40; the initiator is initiator AIBN; the preheating temperature is 50°C; the heating and stirring is stirring at a temperature of 62-72°C for 3-4h; the vacuum drying is vacuum drying at a temperature of 80°C to constant weight; and the DOPO is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0017] The invention discloses a preparation method of a high-hardness and high-temperature resistant powder coating, comprising the following steps: mixing modified acrylic resin, epoxy resin and modified filler at 120° C. for 8-10 minutes, placing in a twin-screw extruder for melt extrusion at 160-180° C., granulating, adding titanium dioxide, a curing agent and a dispersant, extruding granulation, crushing and screening to obtain the coating.

[0018] As a preferred technical solution of the present invention, the preparation method of the modified acrylic resin is: glycidyl methacrylate, butyl methacrylate, methacrylic acid, styrene, benzoyl peroxide and toluene are mixed, heated to 85°C, kept warm for 4 hours, toluene is removed by rotary evaporation, vacuum dried at 80°C for 12 hours, and crushed to obtain the modified acrylic resin.

[0019] Beneficial effects of the present invention:

[0020] The present invention forms a graphene film on the surface of barium sulfate as a composite filler for powder coatings, then modifies the graphene / barium sulfate filler by vinyl salicylaldehyde and diaminophenol, and grafts DOPO with significant thermal stability, thereby improving the high temperature resistance and mechanical properties of the paint film. DETAILED DESCRIPTION

[0021] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0022] Example 1

[0023] A high-hardness, high-temperature-resistant powder coating comprises the following components by weight: 62 parts of modified acrylic resin, 60 parts of epoxy resin, 25 parts of modified filler, 1.4 parts of titanium dioxide, 4 parts of curing agent and 2 parts of dispersing agent; the curing agent is meta-xylylenediamine; the dispersing agent is PE wax.

[0024] The epoxy resin is bisphenol A epoxy resin; the modified acrylic resin is a product of copolymerization of glycidyl methacrylate, butyl methacrylate, methacrylic acid and styrene in a mass ratio of 1:2:1:1.

[0025] Wherein, the preparation method of the modified filler comprises the following steps:

[0026] 1) In a nitrogen atmosphere, barium sulfate is placed in a microwave generator and pressurized and heated, and a reaction gas is introduced for vapor deposition to obtain a composite powder; the pressurization and heating is to heat the mixture to 730° C. under a 5.5 kPa pressure environment; the reaction gas is a mixed gas composed of methane and hydrogen in a volume ratio of 8.5:1.5, and the flow rate of the reaction gas is 0.3 L / min; the amount ratio of the barium sulfate to the reaction gas is 4.8 g:20 L;

[0027] 2) placing the composite powder, vinyl salicylaldehyde and isobutyl alcohol in a reaction kettle, mixing and stirring, adding diaminophenol, heating and mixing, centrifuging to remove the solvent, washing with anhydrous ethanol, and vacuum drying to obtain an intermediate; the heating and mixing is heating at 50° C. for 5 hours; the washing is performed 3 times; the vacuum drying is vacuum drying at 80° C. to constant weight; the diaminophenol is 3,4-diaminophenol; the mass ratio of the composite powder, vinyl salicylaldehyde, diaminophenol and isobutyl alcohol is 10:1.8:1.0:20;

[0028] 3) Mixing anhydrous ethanol and DOPO, stirring, preheating, adding an initiator and an intermediate, heating and stirring, filtering to remove the solvent, and vacuum drying to obtain a modified filler; the mass ratio of DOPO, initiator, intermediate and anhydrous ethanol is 2.0:0.09:15:30; the initiator is initiator AIBN; the preheating temperature is 50°C; the heating and stirring is stirring at 62°C for 3h; the vacuum drying is vacuum drying at 80°C to constant weight; the DOPO is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0029] A preparation method of a high-hardness and high-temperature resistant powder coating comprises the following steps: mixing modified acrylic resin, epoxy resin and modified filler at 120°C for 8 minutes, placing them in a twin-screw extruder for melt extrusion at 160°C, granulating, adding titanium dioxide, a curing agent and a dispersant, extruding granulation, crushing and screening to obtain the coating.

[0030] Example 2

[0031] A high-hardness, high-temperature-resistant powder coating comprises the following components by weight: 64 parts of modified acrylic resin, 61 parts of epoxy resin, 25.8 parts of modified filler, 1.5 parts of titanium dioxide, 4.5 parts of curing agent and 2.5 parts of dispersing agent; the curing agent is meta-xylylenediamine; the dispersing agent is PE wax.

[0032] The epoxy resin is bisphenol A epoxy resin; the modified acrylic resin is a product of copolymerization of glycidyl methacrylate, butyl methacrylate, methacrylic acid and styrene in a mass ratio of 1:2:1:1.

[0033] Wherein, the preparation method of the modified filler comprises the following steps:

[0034] 1) Under a nitrogen atmosphere, barium sulfate is placed in a microwave generator, pressurized and heated, and a reaction gas is introduced for chemical vapor deposition to obtain a composite powder; the pressurized heating is to heat to 735 °C under a pressure environment of 5.5 kPa; the reaction gas is a mixed gas composed of methane and hydrogen in a volume ratio of 8.5:1.5, and the flow rate of the introduced reaction gas is 0.35 L / min; the dosage ratio of barium sulfate to the reaction gas is 4.9 g:21 L;

[0035] 2) The composite powder, vinyl salicylaldehyde and isobutanol are placed in a reaction kettle, mixed and stirred, 3,4-diaminophenol is added and heated and mixed, the solvent is removed by centrifugation, washed with absolute ethanol, and vacuum dried to obtain an intermediate; the heating and mixing is to heat at 52 °C for 5.2 h; the number of washing times is 3 times; the vacuum drying is to vacuum dry at 80 °C to constant weight; the 3,4-diaminophenol is 3,4-diaminophenol; the mass ratio of the composite powder, vinyl salicylaldehyde, 3,4-diaminophenol and isobutanol is 10.2:1.9:1.1:21;

[0036] 3) Absolute ethanol and DOPO are mixed and stirred, an initiator and the intermediate are added after preheating and heated and stirred, the solvent is removed by filtration, and vacuum dried to obtain a modified filler; the mass ratio of DOPO, initiator, intermediate and absolute ethanol is 2.1:0.1:15.2:32; the initiator is initiator AIBN; the preheating temperature is 50 °C; the heating and stirring is to stir at 64 °C for 3.2 h; the vacuum drying is to vacuum dry at 80 °C to constant weight; the DOPO is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0037] A preparation method of a high-hardness and high-temperature-resistant powder coating comprises the following steps: mixing and kneading a modified acrylic resin, an epoxy resin and a modified filler at 120 °C for 8.5 min, melting and extruding at 165 °C in a twin-screw extruder, granulating, adding titanium dioxide, a curing agent and a dispersant, extruding and granulating, pulverizing, and screening to obtain the product.

[0038] Example 3

[0039] A high-hardness and high-temperature-resistant powder coating comprises the following components in parts by weight: 66 parts of a modified acrylic resin, 62 parts of an epoxy resin, 26.5 parts of a modified filler, 1.7 parts of titanium dioxide, 5 parts of a curing agent and 3 parts of a dispersant; the curing agent is m-xylenediamine; the dispersant is PE wax.

[0040] The epoxy resin is bisphenol A epoxy resin; the modified acrylic resin is a copolymerization product of glycidyl methacrylate, butyl methacrylate, methacrylic acid and styrene in a mass ratio of 1:2:1:1.

[0041] Wherein, the preparation method of the modified filler comprises the following steps:

[0042] 1) In a nitrogen atmosphere, barium sulfate is placed in a microwave generator and pressurized and heated, and a reaction gas is introduced for vapor deposition to obtain a composite powder; the pressurization and heating is to heat the barium sulfate to 740° C. under a 5.8 kPa pressure environment; the reaction gas is a mixed gas composed of methane and hydrogen in a volume ratio of 8.5:1.5, and the flow rate of the reaction gas is 0.35 L / min; the amount ratio of the barium sulfate to the reaction gas is 5 g:22 L;

[0043] 2) placing the composite powder, vinyl salicylaldehyde and isobutyl alcohol in a reaction kettle, mixing and stirring, adding diaminophenol, heating and mixing, centrifuging to remove the solvent, washing with anhydrous ethanol, and vacuum drying to obtain an intermediate; the heating and mixing is heating at 55° C. for 5.5 hours; the washing is performed 3 times; the vacuum drying is vacuum drying at 80° C. to constant weight; the diaminophenol is 3,4-diaminophenol; the mass ratio of the composite powder, vinyl salicylaldehyde, diaminophenol and isobutyl alcohol is 10.5:2:1.1:22;

[0044] 3) Mixing anhydrous ethanol and DOPO, stirring, preheating, adding an initiator and an intermediate, heating and stirring, filtering to remove the solvent, and vacuum drying to obtain a modified filler; the mass ratio of DOPO, initiator, intermediate and anhydrous ethanol is 2.2:0.1:15.5:35; the initiator is initiator AIBN; the preheating temperature is 50°C; the heating and stirring is stirring at 65°C for 3.5h; the vacuum drying is vacuum drying at 80°C to constant weight; the DOPO is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0045] A preparation method of a high-hardness and high-temperature resistant powder coating comprises the following steps: mixing modified acrylic resin, epoxy resin and modified filler at 120°C for 9 minutes, placing them in a twin-screw extruder for melt extrusion at 170°C, granulating, adding titanium dioxide, a curing agent and a dispersant, extruding granulation, crushing and screening to obtain the coating.

[0046] Example 4

[0047] A high-hardness, high-temperature-resistant powder coating comprises the following components by weight: 68 parts of modified acrylic resin, 63 parts of epoxy resin, 27 parts of modified filler, 1.8 parts of titanium dioxide, 5.5 parts of curing agent and 3.5 parts of dispersing agent; the curing agent is meta-xylylenediamine; and the dispersing agent is PE wax.

[0048] The epoxy resin is bisphenol A epoxy resin; the modified acrylic resin is a product of copolymerization of glycidyl methacrylate, butyl methacrylate, methacrylic acid and styrene in a mass ratio of 1:2:1:1.

[0049] Wherein, the preparation method of the modified filler comprises the following steps:

[0050] 1) In a nitrogen atmosphere, barium sulfate is placed in a microwave generator and pressurized and heated, and a reaction gas is introduced for vapor deposition to obtain a composite powder; the pressurization and heating is to heat the mixture to 740° C. under a 6 kPa pressure environment; the reaction gas is a mixed gas composed of methane and hydrogen in a volume ratio of 8.5:1.5, and the flow rate of the reaction gas is 0.35 L / min; the amount ratio of the barium sulfate to the reaction gas is 5.1 g:24 L;

[0051] 2) placing the composite powder, vinyl salicylaldehyde and isobutanol in a reaction kettle, mixing and stirring, adding diaminophenol, heating and mixing, centrifuging to remove the solvent, washing with anhydrous ethanol, and vacuum drying to obtain an intermediate; the heating and mixing is heating at 58° C. for 5.8 hours; the washing is performed 3 times; the vacuum drying is vacuum drying at 80° C. to constant weight; the diaminophenol is 3,4-diaminophenol; the mass ratio of the composite powder, vinyl salicylaldehyde, diaminophenol and isobutanol is 10.8:2.1:1.15:24;

[0052] 3) Mixing anhydrous ethanol and DOPO, stirring, preheating, adding an initiator and an intermediate, heating and stirring, filtering to remove the solvent, and vacuum drying to obtain a modified filler; the mass ratio of DOPO, initiator, intermediate and anhydrous ethanol is 2.2:0.11:15.8:38; the initiator is initiator AIBN; the preheating temperature is 50°C; the heating and stirring is stirring at 70°C for 3.8h; the vacuum drying is vacuum drying at 80°C to constant weight; the DOPO is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0053] A preparation method of a high-hardness and high-temperature resistant powder coating comprises the following steps: mixing modified acrylic resin, epoxy resin and modified filler at 120°C for 9 minutes, placing them in a twin-screw extruder for melt extrusion at 175°C, granulating, adding titanium dioxide, a curing agent and a dispersant, extruding granulation, crushing and screening to obtain the coating.

[0054] Example 5

[0055] A high-hardness, high-temperature-resistant powder coating comprises the following components by weight: 70 parts of modified acrylic resin, 64 parts of epoxy resin, 28 parts of modified filler, 2.0 parts of titanium dioxide, 6 parts of curing agent and 4 parts of dispersing agent; the curing agent is meta-xylylenediamine; and the dispersing agent is PE wax.

[0056] The epoxy resin is bisphenol A epoxy resin; the modified acrylic resin is a product of copolymerization of glycidyl methacrylate, butyl methacrylate, methacrylic acid and styrene in a mass ratio of 1:2:1:1.

[0057] Wherein, the preparation method of the modified filler comprises the following steps:

[0058] 1) In a nitrogen atmosphere, barium sulfate is placed in a microwave generator and pressurized and heated, and a reaction gas is introduced for vapor deposition to obtain a composite powder; the pressurization and heating is to heat the barium sulfate to 750° C. under a 6.0 kPa pressure environment; the reaction gas is a mixed gas composed of methane and hydrogen in a volume ratio of 8.5:1.5, and the flow rate of the reaction gas is 0.4 L / min; the amount ratio of the barium sulfate to the reaction gas is 5.2 g:25 L;

[0059] 2) placing the composite powder, vinyl salicylaldehyde and isobutyl alcohol in a reaction kettle, mixing and stirring, adding diaminophenol, heating and mixing, centrifuging to remove the solvent, washing with anhydrous ethanol, and vacuum drying to obtain an intermediate; the heating and mixing is heating at 60° C. for 6 hours; the washing is performed 3 times; the vacuum drying is vacuum drying at 80° C. to constant weight; the diaminophenol is 3,4-diaminophenol; the mass ratio of the composite powder, vinyl salicylaldehyde, diaminophenol and isobutyl alcohol is 11:2.2:1.2:25;

[0060] 3) Mixing anhydrous ethanol and DOPO, stirring, preheating, adding an initiator and an intermediate, heating and stirring, filtering to remove the solvent, and vacuum drying to obtain a modified filler; the mass ratio of DOPO, initiator, intermediate and anhydrous ethanol is 2.3:0.11:16:40; the initiator is initiator AIBN; the preheating temperature is 50°C; the heating and stirring is stirring at 72°C for 4 hours; the vacuum drying is vacuum drying at 80°C to constant weight; the DOPO is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide;

[0061] A preparation method of a high-hardness and high-temperature resistant powder coating comprises the following steps: mixing modified acrylic resin, epoxy resin and modified filler at 120°C for 10 minutes, placing them in a twin-screw extruder for melt extrusion at 180°C, granulating, adding titanium dioxide, a curing agent and a dispersant, extruding granulation, crushing and screening to obtain the coating.

[0062] Comparative Example 1

[0063] Compared with Example 4, Comparative Example 1 is different in that step 1) is not performed, barium sulfate is used instead of the composite powder of step 2), and the remaining components, preparation steps and parameters are uniform.

[0064] Comparative Example 2

[0065] Compared with Example 4, Comparative Example 2 is different in that salicylaldehyde replaces vinyl salicylaldehyde, and the other components, preparation steps and parameters are the same.

[0066] Comparative Example 3

[0067] Compared with Example 4, the difference in Comparative Example 3 is that p-aminophenol replaces diaminophenol, and the other components, preparation steps and parameters are the same.

[0068] Comparative Example 4

[0069] Compared with Example 4, Comparative Example 4 is different in that DOPO is not used, and the other components, preparation steps and parameters are the same.

[0070] Comparative Example 5

[0071] Compared with Example 4, Comparative Example 5 is different in that butyl methacrylate is used instead of methacrylic acid, and the other components, preparation steps and parameters are the same.

[0072] Comparative Example 6

[0073] Compared with Example 4, Comparative Example 6 is different in that butyl methacrylate is used instead of styrene, and the other components, preparation steps and parameters are the same.

[0074] The samples prepared in Examples 1-5 and Comparative Examples 1-6 were subjected to the following performance tests, respectively. The test results are shown in Table 1.

[0075] Hardness test: According to GB / T6739-2006;

[0076] Impact resistance test: According to GB / T1732-2020;

[0077] High temperature resistance test: In a muffle furnace, the test pieces were baked at 350°C for 2h and their appearance was observed.

[0078] Table 1

[0079]

[0080]

[0081] From the test results in Table 1, it can be seen that compared with Comparative Examples 1-6, the powder coatings prepared in Examples 1-5 of the present invention have excellent mechanical strength and high temperature resistance after forming a paint film.

[0082] Through comparative analysis, it can be known that this is because the present invention forms a graphene film on the surface of barium sulfate as a composite filler of powder coating, while reducing the agglomeration of graphene itself, its composite filler can also be embedded between acrylic resin and epoxy resin, achieving the close combination of the two, combined with subsequent organic modification, this structure makes the powder coating after forming a paint film, build a dense three-dimensional network, thereby significantly improving the crosslinking density and hardness of the paint film. The composite of graphene and barium sulfate not only enhances the strength, but also further enhances the thermal stability and mechanical properties of powder coating. Graphene / barium sulfate filler is modified by vinyl salicylaldehyde and diaminophenol, and a benzene ring structure and Schiff base structure with better thermal stability are introduced, while increasing the contact area of ​​the filler and the styrene phase of the modified acrylic resin and the epoxy resin, forming more physical bonding points, and improving compatibility. This further enhances the thermal stability and mechanical properties of powder coating after forming a paint film. In addition, the introduction of phosphorus through carbon-carbon double bond grafting of DOPO with significant thermal stability further improved the high temperature resistance of the paint film, while the DOPO biphenyl structure enhanced the mechanical properties of the paint film.

[0083] Furthermore, the present invention introduces active groups such as carboxyl and epoxy groups into modified acrylic resin, and adopts a physical blending method to enhance the bonding strength between acrylic resin, epoxy resin and modified filler through valence bond bonding. The introduction of styrene phase further improves the compatibility of modified filler in the system and enhances the stability of modified acrylic resin, thereby further improving the high temperature resistance and mechanical properties of the paint film formed by the powder coating.

[0084] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any indirect modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A high-hardness, high-temperature resistant powder coating, characterized in that: The composition comprises the following components by weight: 62-70 parts of modified acrylic resin, 60-64 parts of epoxy resin, 25-28 parts of modified filler, 1.4-2.0 parts of titanium dioxide, 4-6 parts of curing agent and 2-4 parts of dispersant; the curing agent is an amine curing agent; Wherein, the preparation method of the modified filler comprises the following steps: 1) Under a nitrogen atmosphere, barium sulfate is placed in a microwave generator to increase pressure and temperature, and a reaction gas is introduced for vapor deposition to obtain a composite powder; 2) The composite powder, vinyl salicylaldehyde and isobutyl alcohol are placed in a reaction kettle and mixed and stirred, diaminophenol is added and heated and mixed, the solvent is removed by centrifugation, the mixture is washed with anhydrous ethanol, and vacuum dried to obtain an intermediate; 3) Mix anhydrous ethanol and DOPO and stir, add initiator and intermediate after preheating, heat and stir, filter to remove solvent, and vacuum dry to obtain modified filler; The curing agent is m-xylylenediamine; the dispersant is PE wax; The epoxy resin is one or both of bisphenol F epoxy resin and bisphenol A epoxy resin; The modified acrylic resin is a product of copolymerization of glycidyl methacrylate, butyl methacrylate, methacrylic acid and styrene in a mass ratio of 1:2:1:1; In step 1), the pressurization and heating is to heat the mixture to 730-750° C. under a pressure of 5.5-6.0 kPa; the reaction gas is a mixed gas of methane and hydrogen in a volume ratio of 8.5:1.5, and the flow rate of the reaction gas is 0.3-0.4 L / min; the amount ratio of barium sulfate to reaction gas is 4.8-5.2 g:20-25 L.

2. The high-hardness, high-temperature-resistant powder coating according to claim 1, characterized in that: In step 2), the heating and mixing is performed at 50-60°C for 5-6h; the washing is performed 3 times; the vacuum drying is performed at 80°C to constant weight; the mass ratio of the composite powder, vinyl salicylaldehyde, diaminophenol and isobutyl alcohol is 10-11: 1.8-2.2：1.0-1.2：20-25。 3. The high-hardness and high-temperature resistant powder coating according to claim 1, characterized in that: In step 3), the mass ratio of DOPO, initiator, intermediate and anhydrous ethanol is 2.0-2.3:0.09-0.11:15-16:30-40; the initiator is initiator AIBN; the preheating temperature is 50°C; the heating and stirring is stirring at 62-72°C for 3-4h; the vacuum drying is vacuum drying at 80°C to constant weight.

4. A method for preparing a high-hardness, high-temperature resistant powder coating according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: mixing modified acrylic resin, epoxy resin and modified filler at 120° C. for 8-10 minutes, placing in a twin-screw extruder for melt extrusion at 160-180° C., granulating, adding titanium dioxide, a curing agent and a dispersant, extruding granulation, crushing and screening to obtain the product.

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