A nano-ceramic ultra-high hardness powder coating and a preparation method thereof

Abstract

The application discloses a kind of nano ceramic superhard powder coating and preparation method thereof, belong to powder coating preparation technical field.The nano ceramic superhard powder coating described in the application is composed of the following components by weight: 10-20 parts of aluminum oxide, 4-12 parts of zirconium oxide, 5-14 parts of silicon carbide, 2-8 parts of titanium dioxide, 3-7 parts of composite organic auxiliary agent, 53-65 parts of composite resin, 0.5-1.3 parts of dispersing agent, 1-2 parts of anhydrous ethanol, 1-4 parts of leveling agent and 0.4-2.4 parts of coupling agent.The coating prepared by the above method has excellent hardness, chemical corrosion resistance, wear resistance and easy cleaning performance.

Description

Technical Field

[0001] This invention belongs to the field of powder coating preparation technology, specifically relating to a nano-ceramic ultra-high hardness powder coating and its preparation method. Background Technology

[0002] In the field of industrial protection and surface treatment, traditional coating technologies have long faced performance bottlenecks. While conventional products, represented by organic coatings, are widely used, their inherent defects are becoming increasingly apparent: the unsaturated bonds in the molecular structure of organic components are easily damaged by ultraviolet radiation and oxidation, leading to a significant decrease in weather resistance and requiring frequent maintenance for outdoor use. More seriously, in extreme conditions such as aerospace, energy, and chemical industries, traditional coatings cannot withstand high temperatures or rapidly fail under strong acid, alkali, and salt spray corrosion, drastically shortening their protective lifespan. Although engineering ceramic coatings possess a certain degree of high-temperature resistance and corrosion resistance, their high brittleness and low bonding strength limit their application on complex curved surfaces. Against this backdrop, nano-ceramic ultra-high hardness powder coatings have emerged. Through the uniform dispersion of nano-sized ceramic particles and special sintering processes, a composite structure combining ceramic hardness and metallic toughness is formed, effectively breaking through the performance limits of traditional materials in extreme environments and becoming a key technological breakthrough direction in the field of high-end equipment protection.

[0003] Patent CN118791894B discloses a nano-ceramic coating, a nano-ceramic coating method thereof, and its application, relating to the field of coating materials technology. The nano-ceramic coating includes: a silica sol solution, a polysiloxane, and additives; the additives include fillers, which are nanopowders; wherein the weight ratio of the silica sol solution, polysiloxane, and additives is 1:0.5-0.8:1-2. This invention uses silica sol and polysiloxane as film-forming agents. Through the condensation and cross-linking of silica sol and polysiloxane, excessive tensile stress caused by bond shrinkage between sol particles and the substrate surface can be reduced, preventing the coating from self-cracking. Simultaneously, the nanopowder, as a filler, can fill the molecular gaps after the silica sol dehydrates and condenses, and acts as a reinforcement to anchor the relatively formed network structure of the coating, thereby improving the density of the coating, ensuring that the formed coating is free of microcracks, preventing oil and grease residue from remaining in the coating, and ensuring good cleanability and long-lasting durability. Although the aforementioned patents significantly improved the coating density through the condensation crosslinking of silica sol and polysiloxane and the use of nanopowder fillers, there is still potential for optimization in terms of hardness, high temperature resistance, and weather resistance. Currently, the types and particle size distribution of nanopowder fillers may not be fully matched with the crosslinking network structure, resulting in the strengthening effect not reaching the theoretical limit. The crosslinking agent system has limited enhancement of the stability of chemical bonds at high temperatures, and long-term heat resistance depends on the modification depth of the base film-forming agent. Furthermore, there is a lack of active protection mechanisms against ultraviolet radiation and oxidizing atmospheres, and photocatalytic degradation and microcrack propagation may still occur during outdoor aging. Summary of the Invention

[0004] The purpose of this invention is to provide a nano-ceramic ultra-high hardness powder coating and its preparation method, which solves the technical problems of poor hardness, high temperature resistance and easy cleaning performance of existing powder coatings.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a nano-ceramic ultra-high hardness powder coating, which is composed of the following components by weight: 10-20 parts alumina, 4-12 parts zirconium oxide, 5-14 parts silicon carbide, 2-8 parts titanium dioxide, 3-7 parts composite organic additives, 53-65 parts composite resin, 0.5-1.3 parts dispersant, 1-2 parts anhydrous ethanol, 1-4 parts leveling agent and 0.4-2.4 parts coupling agent.

[0007] Preferably, the preparation method of the composite organic additive includes the following steps:

[0008] Q1: 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, lauryl methacrylate, 3-mercaptopropyltriethoxysilane and azobisisobutyronitrile were added to a container containing tetrahydrofuran, argon gas was introduced, and the reaction was heated. After the reaction was completed, the mixture was rotary evaporated, precipitated, and dried under vacuum to obtain a colorless and transparent liquid 1.

[0009] Q2: Add γ-glycidyl etheroxypropyltrimethoxysilane, distilled water and hydrochloric acid to a solution containing ethanol, heat and stir under an argon atmosphere, then add colorless transparent liquid 1, distilled water and hydrochloric acid in sequence, continue stirring and reacting, after the reaction is completed, rotary evaporate and dry to obtain a composite organic auxiliary agent.

[0010] In the above process, in tetrahydrofuran solvent, azobisisobutyronitrile undergoes homolytic cleavage upon heating to generate free radicals, which attack the double bonds to form a growing chain. The thiol group terminates the growing chain through a chain transfer reaction and introduces a silane end group, yielding a colorless and transparent liquid 1. Then, γ-glycidoxypropyltrimethoxysilane is hydrolyzed under acid catalysis to generate silanols. Subsequently, the silanols condense to form a siloxane network structure. At the same time, the colorless and transparent liquid 1 is added, and its silane groups further condense with the silanols to form a cross-linked structure, resulting in a composite organic auxiliary agent.

[0011] Preferably, in Q1, the ratio of 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, lauryl methacrylate, 3-mercaptopropyltriethoxysilane, azobisisobutyronitrile, and tetrahydrofuran is (3.88-4.12) g : (4.12-5.35) g : (1.01-1.39) g : (0.01-0.03) g : (10-20) mL, the reaction temperature is 70-80℃, and the reaction time is 20-24 h.

[0012] Preferably, in Q2, the ratio of γ-glycidyl etheroxypropyltrimethoxysilane to colorless transparent liquid 1 is (21.12-25.45) g: (8.72-9.32) g, the heating and stirring reaction temperature is 60-65℃, the time is 3-5 h, and the stirring reaction time is continued for 4-6 h.

[0013] Preferably, the method for preparing the composite resin includes the following steps:

[0014] S1: Under nitrogen atmosphere, 2-chloro-5-nitrobenzaldehyde, 4,4'-difluorobenzoyl and ammonium acetate were added to a container containing acetic acid, heated and stirred to react, refluxed, cooled, filtered, washed and recrystallized to obtain organic compound a;

[0015] S2: Add organic compound a, potassium carbonate and p-nitrophenol to a container containing N,N-dimethylformamide, heat and stir to react. After the reaction is complete, cool, add deionized water, filter, wash, and filter while hot to obtain organic compound b.

[0016] S3: Under nitrogen atmosphere, organic compound b was added to ethanol, stirred and mixed, Pd / C was added, the mixture was heated and stirred, hydrazine hydrate was added, stirred and mixed, and then refluxed. After the reaction was completed, the mixture was filtered while hot, rotary evaporated, and recrystallized to obtain organic compound c.

[0017] S4: Add organic compound c to a container containing N-methylpyrrolidone, stir and mix, then add 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride, react, and heat to obtain composite resin.

[0018] The synthesis reaction formula for the composite resin in the above process is as follows:

[0019]

[0020] The mass spectrometry analysis results of organic compound a were: m / z: 411.06 (100.0%), 413.06 (32.6%), 412.06 (24.0%), 414.06 (7.4%), 413.07 (2.5%), 415.06 (1.0%); the mass spectrometry analysis results of organic compound b were: m / z: 514.11 (100.0%), 515.11 (30.9%), 516.12 (4.2%), 516.11 (1.5%); and the mass spectrometry analysis results of organic compound c were: m / z: 454.16 (100.0%), 455.16 (30.7%), 456.17 (4.2%).

[0021] Preferably, in S1, the ratio of 2-chloro-5-nitrobenzaldehyde, 4,4'-difluorobenzoyl, ammonium acetate, and acetic acid is (1.483-2.048) g : (2.122-2.894) g : (5.121-5.483) g : (25-35) mL, the heating and stirring reaction temperature is 110-120℃, the time is 1-2 h, and the reflux is condensed for 10-12 h.

[0022] Preferably, in S2, the ratio of organic compound a, potassium carbonate, p-nitrophenol and N,N-dimethylformamide is (4.88-5.32) g : (1.988-2.046) g : (1.923-2.114) g : (48-52) mL, and the mixture is heated to 70-75℃ and stirred for 10-12 h.

[0023] Preferably, in S3, the ratio of organic compound b, ethanol, Pd / C and hydrazine hydrate is (5.48-6.41) g : (125-178) mL : (0.532-0.688) g : (23-28) mL, the temperature is raised to 70-72℃, stirred for 40-45 min, and refluxed for 10-12 h.

[0024] Preferably, in step S4, the ratio of organic compound c, N-methylpyrrolidone, and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride is (2.12-2.78) g : (20-30) mL : (4.23-4.66) g, and the reaction is carried out for 6-8 hours. The heating process is as follows: the temperature is raised to 60℃, 100℃, 150℃, 200℃, 250℃, and 300℃ in sequence, and the reaction is maintained at each temperature for 1 hour. The heating rate is 5℃ / min.

[0025] Preferably, the preparation method of the nano-ceramic ultra-high hardness powder coating includes the following steps:

[0026] Step 1: Add alumina, zirconium oxide, silicon carbide and titanium dioxide to a vacuum drying oven in sequence and dry. Then dilute the coupling agent with anhydrous ethanol, spray it on the surface of the pretreated powder, mix and stir to obtain the pretreated powder.

[0027] Step 2: Mix and stir the composite organic additive, composite resin, dispersant and leveling agent to obtain a composite mixed additive;

[0028] Step 3: Add the pretreated powder and composite additives to a container, mix, melt extrude, plasticize, cool, pulverize, and sieve to obtain a nano-ceramic ultra-high hardness powder coating.

[0029] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0030] 1. The present invention adds the prepared composite organic additives and composite resins to the preparation process of nano-ceramic ultra-high hardness powder coatings, which can effectively improve its thermal stability, adhesion, anti-fouling performance, chemical resistance and hardness.

[0031] 2. This invention adds the obtained composite organic additive to nano-ceramic ultra-high hardness powder coating, which can significantly improve the dispersibility of nano-ceramic particles. The composite organic additive forms strong covalent bonds with the surface of nano-ceramic particles, playing an anchoring role. Furthermore, the long-chain alkyl and fluorocarbon chains it contains form an organic shell layer on the particle surface, generating a steric hindrance effect, preventing particles from approaching each other and agglomerating. This results in more uniform dispersion of nano-ceramic particles in the coating system, forming a stable and homogeneous dispersion, improving the density and smoothness of the coating. The composite organic additive can enhance the adhesion between the coating and the substrate through coupling bridging, interfacial penetration and interweaving. The fluorocarbon chains and long-chain alkyl groups contained in the composite organic additive can effectively reduce the surface energy of the coating, improving its anti-fouling performance. Simultaneously, the long-chain alkyl groups can also be embedded in the inorganic ceramic network, reducing brittleness and improving the flexibility of the coating. The fluorine groups and silane network in the composite organic additive provide excellent chemical resistance, resisting acid, alkali, solvent and UV degradation, maintaining the integrity of the coating, and preventing deterioration during long-term use.

[0032] 3. This invention applies the prepared composite resin to nano-ceramic ultra-high hardness powder coatings, which can effectively improve the coating's hardness, wear resistance, chemical corrosion resistance, and easy-to-clean properties. The conjugated structure of the imide ring and aromatic ring in the polyimide backbone of the composite resin endows the coating with high modulus, forming a three-dimensional network to resist external deformation. The rigid structure of the imidazole ring and the polyimide segments form a hydrogen bond network, which absorbs impact energy through energy dissipation mechanism during crack propagation, thereby improving its hardness and wear resistance. The presence of polyimide and fluorinated groups can also improve the coating's high-temperature resistance and chemical resistance. At the same time, the hydrophobic and oleophobic properties of the fluorinated groups give the coating excellent easy-to-clean properties. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1: This example discloses a method for preparing a composite organic additive, including the following steps:

[0035] Q1: 3.98g of 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, 4.83g of lauryl methacrylate, 1.20g of 3-mercaptopropyltriethoxysilane and 0.02g of azobisisobutyronitrile were added to a container containing 15mL of tetrahydrofuran, argon gas was introduced, and the mixture was heated at 70℃ for 24h. After the reaction was completed, the mixture was rotary evaporated, precipitated, and dried under vacuum to obtain a colorless and transparent liquid 1.

[0036] Q2: Add 25.53g of γ-glycidyl etheroxypropyltrimethoxysilane, 3.1g of distilled water and 0.2g of 1mol / L hydrochloric acid to a solution containing 20mL of ethanol. Under an argon atmosphere, heat and stir at 60℃ for 4h. Then add 8.94g of colorless transparent liquid 1, 0.2g of distilled water and 0.1g of 1mol / L hydrochloric acid in sequence, and continue stirring for 6h. After the reaction is completed, rotary evaporate and dry to obtain the composite organic auxiliary agent.

[0037] This embodiment discloses a method for preparing a composite resin, including the following steps:

[0038] S1: Under nitrogen atmosphere, 1.721 g of 2-chloro-5-nitrobenzaldehyde, 2.453 g of 4,4'-difluorobenzoyl and 5.302 g of ammonium acetate were added to a container containing 30 mL of acetic acid. The mixture was heated and stirred at 110 °C for 2 h, then refluxed for 12 h. After the reaction was completed, the mixture was cooled, filtered, washed, and recrystallized to obtain organic compound a.

[0039] S2: Add 5.05g of organic compound a, 2.012g of potassium carbonate and 2.013g of p-nitrophenol to a container containing 50mL of N,N-dimethylformamide, heat to 75℃ and stir for 12h. After the reaction is complete, cool, add deionized water, filter, wash, and filter while hot to obtain organic compound b.

[0040] S3: Under nitrogen atmosphere, 6.04 g of organic compound b was added to 145 mL of ethanol and stirred. After mixing, 0.605 g of Pd / C was added, the temperature was raised to 70 °C and stirred for 45 min. Then, 25 mL of hydrazine hydrate was added, stirred and mixed, and refluxed for 12 h. After the reaction was completed, the mixture was filtered while hot, rotary evaporated, and recrystallized to obtain organic compound c.

[0041] S4: Add 2.45g of organic compound c to a container containing 25mL of N-methylpyrrolidone, stir and mix, then add 4.44g of 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride, react for 8h, and then heat the mixture. The process is as follows: successively raise the temperature to 60℃, 100℃, 150℃, 200℃, 250℃ and 300℃, and keep the reaction at each temperature for 1h. The heating rate is 5℃ / min, and the composite resin is obtained.

[0042] This embodiment discloses a nano-ceramic ultra-high hardness powder coating, which is composed of the following components by weight: 15 parts alumina, 8 parts zirconium oxide, 9.5 parts silicon carbide, 5 parts titanium dioxide, 5 parts composite organic additives, 59 parts composite resin, 0.9 parts nano zirconium dioxide dispersant, 1.5 parts anhydrous ethanol, 2.5 parts polybutyl acrylate and 1.4 parts coupling agent KH-570.

[0043] This embodiment discloses a method for preparing a nano-ceramic ultra-high hardness powder coating, including the following steps:

[0044] Step 1: Add alumina, zirconium oxide, silicon carbide and titanium dioxide to a vacuum drying oven in sequence and dry. Then dilute the coupling agent KH-570 with anhydrous ethanol, spray it on the surface of the pretreated powder, mix and stir to obtain the pretreated powder.

[0045] Step 2: Mix and stir the composite organic additive, composite resin, nano-zirconia dispersant and polybutyl acrylate to obtain a composite mixed additive;

[0046] Step 3: Add the pretreated powder and composite additives to a container, mix, melt extrude, plasticize, cool, pulverize, and sieve to obtain a nano-ceramic ultra-high hardness powder coating.

[0047] Example 2: This example discloses a method for preparing a composite organic additive, including the following steps:

[0048] Q1: 3.88g of 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, 4.12g of lauryl methacrylate, 1.01g of 3-mercaptopropyltriethoxysilane and 0.01g of azobisisobutyronitrile were added to a container containing 20mL of tetrahydrofuran, argon gas was introduced, and the mixture was heated at 70℃ for 24h. After the reaction was completed, the mixture was rotary evaporated, precipitated, and dried under vacuum to obtain a colorless and transparent liquid 1.

[0049] Q2: 21.12g of γ-glycidyl etheroxypropyltrimethoxysilane, 3.1g of distilled water and 0.2g of 1mol / L hydrochloric acid were added to a solution containing 20mL of ethanol. The mixture was heated and stirred at 60℃ for 4h under an argon atmosphere. Then, 8.72g of colorless transparent liquid 1, 0.2g of distilled water and 0.1g of 1mol / L hydrochloric acid were added sequentially, and the mixture was stirred and stirred for another 6h. After the reaction was completed, the mixture was rotary evaporated and dried to obtain the composite organic auxiliary agent.

[0050] This embodiment discloses a method for preparing a composite resin, including the following steps:

[0051] S1: Under nitrogen atmosphere, 1.483 g of 2-chloro-5-nitrobenzaldehyde, 2.122 g of 4,4'-difluorobenzoyl and 5.121 g of ammonium acetate were added to a container containing 35 mL of acetic acid. The mixture was heated and stirred at 110 °C for 2 h, then refluxed for 12 h. After the reaction was completed, the mixture was cooled, filtered, washed, and recrystallized to obtain organic compound a.

[0052] S2: Add 4.88g of organic compound a, 1.988g of potassium carbonate and 1.923g of p-nitrophenol to a container containing 52mL of N,N-dimethylformamide, heat to 75℃ and stir for 12h. After the reaction is complete, cool, add deionized water, filter, wash, and filter while hot to obtain organic compound b.

[0053] S3: Under nitrogen atmosphere, 5.48 g of organic compound b was added to 125 mL of ethanol and stirred. After mixing, 0.532 g of Pd / C was added, the temperature was raised to 70 °C and stirred for 45 min. Then, 28 mL of hydrazine hydrate was added, stirred and mixed, and refluxed for 12 h. After the reaction was completed, the mixture was filtered while hot, rotary evaporated, and recrystallized to obtain organic compound c.

[0054] S4: Add 2.12g of organic compound c to a container containing 20mL of N-methylpyrrolidone, stir and mix, then add 4.23g of 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride, react for 8h, and then heat the mixture. The process is as follows: successively raise the temperature to 60℃, 100℃, 150℃, 200℃, 250℃ and 300℃, and keep the reaction at each temperature for 1h. The heating rate is 5℃ / min, and the composite resin is obtained.

[0055] This embodiment discloses a nano-ceramic ultra-high hardness powder coating, which is composed of the following components by weight: 10 parts alumina, 12 parts zirconium oxide, 5 parts silicon carbide, 2 parts titanium dioxide, 7 parts composite organic additives, 53 parts composite resin, 0.5 parts dispersant ER60, 2 parts anhydrous ethanol, 1 part ethyl acrylate-butyl acrylate copolymer and 2.4 parts coupling agent A-172.

[0056] This embodiment discloses a method for preparing a nano-ceramic ultra-high hardness powder coating, including the following steps:

[0057] Step 1: Add alumina, zirconium oxide, silicon carbide and titanium dioxide to a vacuum drying oven in sequence and dry. Then dilute coupling agent A-172 with anhydrous ethanol, spray it on the surface of the pretreated powder, mix and stir to obtain the pretreated powder.

[0058] Step 2: Mix and stir the composite organic additive, composite resin, dispersant ER60 and ethyl acrylate-butyl copolymer to obtain a composite mixed additive;

[0059] Step 3: Add the pretreated powder and composite additives to a container, mix, melt extrude, plasticize, cool, pulverize, and sieve to obtain a nano-ceramic ultra-high hardness powder coating.

[0060] Example 3: This example discloses a method for preparing a composite organic additive, including the following steps:

[0061] Q1: 4.12g of 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, 5.35g of lauryl methacrylate, 1.39g of 3-mercaptopropyltriethoxysilane and 0.03g of azobisisobutyronitrile were added to a container containing 10mL of tetrahydrofuran, argon gas was introduced, and the mixture was heated at 70℃ for 24h. After the reaction was completed, the mixture was rotary evaporated, precipitated, and dried under vacuum to obtain a colorless and transparent liquid 1.

[0062] Q2: Add 25.45g of γ-glycidyl etheroxypropyltrimethoxysilane, 3.1g of distilled water and 0.2g of 1mol / L hydrochloric acid to a solution containing 20mL of ethanol. Under an argon atmosphere, heat and stir at 60℃ for 4h. Then add 9.32g of colorless transparent liquid 1, 0.2g of distilled water and 0.1g of 1mol / L hydrochloric acid in sequence, and continue stirring for 6h. After the reaction is completed, rotary evaporate and dry to obtain the composite organic auxiliary agent.

[0063] This embodiment discloses a method for preparing a composite resin, including the following steps:

[0064] S1: Under nitrogen atmosphere, 2.048 g of 2-chloro-5-nitrobenzaldehyde, 2.894 g of 4,4'-difluorobenzoyl and 5.483 g of ammonium acetate were added to a container containing 25 mL of acetic acid. The mixture was heated and stirred at 110 °C for 2 h, then refluxed for 12 h. After the reaction was completed, the mixture was cooled, filtered, washed, and recrystallized to obtain organic compound a.

[0065] S2: Add 5.32g of organic compound a, 2.046g of potassium carbonate and 2.114g of p-nitrophenol to a container containing 48mL of N,N-dimethylformamide, heat to 75℃ and stir for 12h. After the reaction is complete, cool, add deionized water, filter, wash, and filter while hot to obtain organic compound b.

[0066] S3: Under nitrogen atmosphere, 6.41 g of organic compound b was added to 178 mL of ethanol and stirred. After mixing, 0.688 g of Pd / C was added, the temperature was raised to 70 °C and stirred for 45 min. Then, 23 mL of hydrazine hydrate was added, stirred and mixed, and refluxed for 12 h. After the reaction was completed, the mixture was filtered while hot, rotary evaporated, and recrystallized to obtain organic compound c.

[0067] S4: Add 2.78g of organic compound c to a container containing 22mL of N-methylpyrrolidone, stir and mix, then add 4.66g of 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride, react for 8h, and then heat the mixture. The process is as follows: successively raise the temperature to 60℃, 100℃, 150℃, 200℃, 250℃ and 300℃, and keep the reaction at each temperature for 1h. The heating rate is 5℃ / min, and the composite resin is obtained.

[0068] This embodiment discloses a nano-ceramic ultra-high hardness powder coating, which is composed of the following components by weight: 20 parts alumina, 4 parts zirconium oxide, 14 parts silicon carbide, 8 parts titanium dioxide, 3 parts composite organic additives, 65 parts composite resin, 1.3 parts dispersant ER60, 1 part anhydrous ethanol, 4 parts GLP503 and 0.4 parts coupling agent KH-550.

[0069] This embodiment discloses a method for preparing a nano-ceramic ultra-high hardness powder coating, including the following steps:

[0070] Step 1: Add alumina, zirconium oxide, silicon carbide and titanium dioxide to a vacuum drying oven in sequence and dry. Then dilute the coupling agent KH-550 with anhydrous ethanol, spray it on the surface of the pretreated powder, mix and stir to obtain the pretreated powder.

[0071] Step 2: Mix and stir the composite organic additive, composite resin, dispersant ER60 and GLP503 to obtain a composite mixed additive;

[0072] Step 3: Add the pretreated powder and composite additives to a container, mix, melt extrude, plasticize, cool, pulverize, and sieve to obtain a nano-ceramic ultra-high hardness powder coating.

[0073] Example 4: This example discloses a method for preparing a composite organic additive, including the following steps:

[0074] Q1: 3.95g of 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, 4.48g of lauryl methacrylate, 1.11g of 3-mercaptopropyltriethoxysilane and 0.015g of azobisisobutyronitrile were added to a container containing 12mL of tetrahydrofuran, argon gas was introduced, and the mixture was heated at 70℃ for 24h. After the reaction was completed, the mixture was rotary evaporated, precipitated, and dried under vacuum to obtain a colorless and transparent liquid 1.

[0075] Q2: 22.32g of γ-glycidyl etheroxypropyltrimethoxysilane, 3.1g of distilled water and 0.2g of 1mol / L hydrochloric acid were added to a solution containing 20mL of ethanol. The mixture was heated and stirred at 60℃ for 4h under an argon atmosphere. Then, 8.89g of colorless transparent liquid 1, 0.2g of distilled water and 0.1g of 1mol / L hydrochloric acid were added sequentially, and the mixture was stirred and stirred for another 6h. After the reaction was completed, the mixture was rotary evaporated and dried to obtain the composite organic auxiliary agent.

[0076] This embodiment discloses a method for preparing a composite resin, including the following steps:

[0077] S1: Under nitrogen atmosphere, 1.611 g of 2-chloro-5-nitrobenzaldehyde, 2.271 g of 4,4'-difluorobenzoyl and 5.202 g of ammonium acetate were added to a container containing 28 mL of acetic acid. The mixture was heated and stirred at 110 °C for 2 h, then refluxed for 12 h. After the reaction was completed, the mixture was cooled, filtered, washed, and recrystallized to obtain organic compound a.

[0078] S2: Add 4.96g of organic compound a, 2.002g of potassium carbonate and 1.987g of p-nitrophenol to a container containing 49mL of N,N-dimethylformamide, heat to 75℃ and stir for 12h. After the reaction is complete, cool, add deionized water, filter, wash, and filter while hot to obtain organic compound b.

[0079] S3: Under nitrogen atmosphere, 5.72 g of organic compound b was added to 130 mL of ethanol and stirred. After mixing, 0.574 g of Pd / C was added, the temperature was raised to 70 °C and stirred for 45 min. Then, 24 mL of hydrazine hydrate was added, stirred and mixed, and refluxed for 12 h. After the reaction was completed, the mixture was filtered while hot, rotary evaporated, and recrystallized to obtain organic compound c.

[0080] S4: Add 2.28g of organic compound c to a container containing 30mL of N-methylpyrrolidone, stir and mix, then add 4.33g of 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride, react for 8h, and then heat the mixture. The process is as follows: the temperature is raised to 60℃, 100℃, 150℃, 200℃, 250℃ and 300℃ in sequence, and the reaction is maintained at each temperature for 1h. The heating rate is 5℃ / min, and the composite resin is obtained.

[0081] This embodiment discloses a nano-ceramic ultra-high hardness powder coating, which is composed of the following components by weight: 12 parts alumina, 6 parts zirconium oxide, 8 parts silicon carbide, 3 parts titanium dioxide, 4 parts composite organic additives, 55 parts composite resin, 0.7 parts dispersant ER60, 1.2 parts anhydrous ethanol, 2 parts GLP505 and 0.9 parts coupling agent KH-570.

[0082] This embodiment discloses a method for preparing a nano-ceramic ultra-high hardness powder coating, including the following steps:

[0083] Step 1: Add alumina, zirconium oxide, silicon carbide and titanium dioxide to a vacuum drying oven in sequence and dry. Then dilute the coupling agent KH-570 with anhydrous ethanol, spray it on the surface of the pretreated powder, mix and stir to obtain the pretreated powder.

[0084] Step 2: Mix and stir the composite organic additive, composite resin, dispersant ER60 and GLP505 to obtain a composite mixed additive;

[0085] Step 3: Add the pretreated powder and composite additives to a container, mix, melt extrude, plasticize, cool, pulverize, and sieve to obtain a nano-ceramic ultra-high hardness powder coating.

[0086] Example 5: This example discloses a method for preparing a composite organic additive, including the following steps:

[0087] Q1: 4.06 g of 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, 5.12 g of lauryl methacrylate, 1.27 g of 3-mercaptopropyltriethoxysilane and 0.025 g of azobisisobutyronitrile were added to a container containing 18 mL of tetrahydrofuran, argon gas was introduced, and the mixture was heated at 70 °C for 24 h. After the reaction was completed, the mixture was rotary evaporated, precipitated, and dried under vacuum to obtain a colorless and transparent liquid 1.

[0088] Q2: Add 24.48g of γ-glycidyl etheroxypropyltrimethoxysilane, 3.1g of distilled water and 0.2g of 1mol / L hydrochloric acid to a solution containing 20mL of ethanol. Under an argon atmosphere, heat and stir at 60℃ for 4h. Then add 9.15g of colorless transparent liquid 1, 0.2g of distilled water and 0.1g of 1mol / L hydrochloric acid in sequence, and continue stirring for 6h. After the reaction is completed, evaporate by rotary evaporation and dry to obtain the composite organic auxiliary agent.

[0089] This embodiment discloses a method for preparing a composite resin, including the following steps:

[0090] S1: Under nitrogen atmosphere, 1.934 g of 2-chloro-5-nitrobenzaldehyde, 2.636 g of 4,4'-difluorobenzoyl and 5.357 g of ammonium acetate were added to a container containing 32 mL of acetic acid. The mixture was heated and stirred at 110 °C for 2 h, then refluxed for 12 h. After the reaction was completed, the mixture was cooled, filtered, washed, and recrystallized to obtain organic compound a.

[0091] S2: Add 5.16g of organic compound a, 2.029g of potassium carbonate and 2.093g of p-nitrophenol to a container containing 51mL of N,N-dimethylformamide, heat to 75℃ and stir for 12h. After the reaction is completed, cool, add deionized water, filter, wash, and filter while hot to obtain organic compound b.

[0092] S3: Under nitrogen atmosphere, 6.18 g of organic compound b was added to 165 mL of ethanol and stirred. After mixing, 0.623 g of Pd / C was added, the temperature was raised to 70 °C and stirred for 45 min. Then, 27 mL of hydrazine hydrate was added, stirred and mixed, and refluxed for 12 h. After the reaction was completed, the mixture was filtered while hot, rotary evaporated, and recrystallized to obtain organic compound c.

[0093] S4: Add 2.58g of organic compound c to a container containing 28mL of N-methylpyrrolidone, stir and mix, then add 4.57g of 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride, react for 8h, and then heat the mixture. The process is as follows: successively raise the temperature to 60℃, 100℃, 150℃, 200℃, 250℃ and 300℃, and keep the reaction at each temperature for 1h. The heating rate is 5℃ / min, and the composite resin is obtained.

[0094] This embodiment discloses a nano-ceramic ultra-high hardness powder coating, which is composed of the following components by weight: 18 parts alumina, 10 parts zirconium oxide, 12 parts silicon carbide, 7 parts titanium dioxide, 6 parts composite organic additives, 62 parts composite resin, 1.2 parts dispersant ER60, 1.8 parts anhydrous ethanol, 3 parts polybutyl acrylate and 1.9 parts DL-411.

[0095] This embodiment discloses a method for preparing a nano-ceramic ultra-high hardness powder coating, including the following steps:

[0096] Step 1: Add alumina, zirconium oxide, silicon carbide and titanium dioxide to a vacuum drying oven in sequence and dry. Then dilute DL-411 with anhydrous ethanol, spray it on the surface of the pretreated powder, mix and stir to obtain the pretreated powder.

[0097] Step 2: Mix and stir the composite organic additive, composite resin, dispersant ER60 and polybutyl acrylate to obtain a composite mixed additive;

[0098] Step 3: Add the pretreated powder and composite additives to a container, mix, melt extrude, plasticize, cool, pulverize, and sieve to obtain a nano-ceramic ultra-high hardness powder coating.

[0099] Comparative Example 1: Compared with Example 1, Comparative Example 1 did not add composite organic additives in the process of preparing nano-ceramic ultra-high hardness powder coating, and all other conditions remained unchanged.

[0100] Comparative Example 2: Compared with Example 1, Comparative Example 2 used p-phenylenediamine instead of organic compound c to prepare the composite resin in the process of preparing nano-ceramic ultra-high hardness powder coating, while other conditions remained unchanged.

[0101] Comparative Example 3: Compared with Example 1, Comparative Example 3 did not add composite organic additives in the process of preparing nano-ceramic ultra-high hardness powder coating, and used p-phenylenediamine to replace organic compound c to prepare composite resin, while other conditions remained unchanged.

[0102] Performance testing:

[0103] The nano-ceramic ultra-high hardness powder coatings prepared according to Examples 1-5 and Comparative Examples 1-3 were treated by spraying to ensure uniform adhesion to the substrate surface. The spraying environment temperature was 20℃, the humidity was controlled at 60%, the spray gun nozzle diameter was 1mm, the spraying pressure was 0.6MPa, the distance between the spray gun nozzle and the substrate was 20cm, and the coating thickness was 20μm. After spraying, a curing process was performed: first, the sprayed substrate was placed in a low-temperature curing oven at 150℃ for 15min, and then placed in a high-temperature curing oven at 240℃ for 15min to obtain the nano-ceramic ultra-high hardness powder coating. The hardness of the sample was tested according to GB / T 6739-2022, and the wear resistance of the sample was tested according to GB / T 1768-2006. The corrosion resistance of the samples was tested according to standard 30648.1-2014, and the adhesion performance was tested according to GB / T39685-2020. Tomato sauce was placed on the coating surface, then baked at 220℃ for 15 minutes, and then wiped off with a scouring pad to test the easy-to-clean performance of the samples. The test results are shown in Table 1.

[0104] Table 1

[0105]

[0106] As shown in Table 1, the test results indicate that nano-ceramic ultra-high hardness powder coatings with excellent hardness, wear resistance, corrosion resistance, adhesion, and easy cleaning properties can be prepared using the methods of Examples 1-5. The hardness of Examples 1-5 is all 9H, while the hardness of Comparative Example 1 decreases to 8H, and Comparative Examples 2 and 3 both decrease to 7H. Comparative Example 1's hardness decreases due to the lack of interfacial anchoring effect from the composite organic additive. Comparative Example 2's hardness further decreases because the use of p-phenylenediamine to replace organic compound c disrupts the synergistic hardening mechanism of polyimide-fluorinated groups. Comparative Example 3 lacks both, resulting in the lowest hardness. The weight loss rate of Examples 1-5 is all below 0.1%, increasing sequentially from Comparative Example 1 and 2 to the highest in Comparative Example 3. This is mainly due to the presence of polyimide in the composite resin. The energy dissipation mechanism of the hydrogen bond network of imine during crack propagation, and the synergistic effect of long-chain alkyl groups embedded in the inorganic network in the composite organic additive reducing brittleness and fluorocarbon chains reducing surface friction, were observed. Comparative Example 1, due to the steric hindrance effect of the lack of composite organic additives, experienced particle agglomeration leading to increased wear. Comparative Example 2, due to changes in the composite resin structure, had its hydrogen bond network disrupted, resulting in a significant decrease in wear resistance. Comparative Example 3, lacking both, exhibited the highest weight loss rate. In different corrosive solvents, Examples 1-5 showed lower loss rates, while Comparative Examples 1 and 2 had similar but higher mass loss rates than Examples 5. Examples 1-5 show that Comparative Example 3 has the highest resistance, mainly due to the chemical resistance provided by the fluorine groups and silane network in the composite organic additive, and the stabilizing effect of the fluorinated groups in the composite resin. Comparative Example 3, lacking both, has the worst corrosion resistance. Examples 1-5 show higher tensile bond strength in their coatings, while Comparative Examples 1 and 3 show lower strength. Comparative Example 2 is similar to Examples 1-5, mainly due to the coupling bridging effect and interfacial penetration interweaving effect of the composite organic additive. Comparative Example 1, lacking anchoring effect, has reduced bond strength. Although Comparative Example 2 replaced the resin... The composite organic additives were retained in the example, and the bonding strength was close to that of the example, indicating that the composite organic additives played a dominant role in the adhesion. Comparative Example 3 lacked both and had the lowest bonding strength. Examples 1-5 and Comparative Examples 1-2 were all "easy to wipe off", while Comparative Example 3 was "difficult to wipe off". The fluorocarbon chains and long-chain alkyl groups in the composite organic additives reduced the surface energy of the coating, so that the tomato sauce could still be removed by physical wiping after high-temperature baking. Comparative Example 3 had an increased surface energy due to the composite organic additives and composite resin, which enhanced the adhesion between the stain and the coating, resulting in "difficult to wipe off".

[0107] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0108] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A nano-ceramic ultra-high hardness powder coating, characterized in that, It is composed of the following components by weight: 10-20 parts alumina, 4-12 parts zirconium oxide, 5-14 parts silicon carbide, 2-8 parts titanium dioxide, 3-7 parts composite organic additives, 53-65 parts composite resin, 0.5-1.3 parts dispersant, 1-2 parts anhydrous ethanol, 1-4 parts leveling agent and 0.4-2.4 parts coupling agent; The preparation method of the composite organic additive includes the following steps: Q1: 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, lauryl methacrylate, 3-mercaptopropyltriethoxysilane and azobisisobutyronitrile were added to a container containing tetrahydrofuran, argon gas was introduced, and the reaction was heated. After the reaction was completed, the mixture was rotary evaporated, precipitated, and dried under vacuum to obtain a colorless and transparent liquid 1. Q2: Add γ-glycidyl etheroxypropyltrimethoxysilane, distilled water and hydrochloric acid to a container containing ethanol, heat and stir under an argon atmosphere, then add colorless transparent liquid 1, distilled water and hydrochloric acid in sequence, continue stirring and reacting, after the reaction is completed, rotary evaporate and dry to obtain a composite organic auxiliary agent; The method for preparing the composite resin includes the following steps: S1: Under nitrogen atmosphere, 2-chloro-5-nitrobenzaldehyde, 4,4'-difluorobenzoyl and ammonium acetate were added to a container containing acetic acid, heated and stirred to react, refluxed, cooled, filtered, washed and recrystallized to obtain organic compound a; S2: Add organic compound a, potassium carbonate and p-nitrophenol to a container containing N,N-dimethylformamide, heat and stir to react. After the reaction is complete, cool, add deionized water, filter, wash, and filter while hot to obtain organic compound b. S3: Under nitrogen atmosphere, organic compound b was added to ethanol, stirred and mixed, Pd / C was added, the mixture was heated and stirred, hydrazine hydrate was added, stirred and mixed, and then refluxed. After the reaction was completed, the mixture was filtered while hot, rotary evaporated, and recrystallized to obtain organic compound c. S4: Add organic compound c to a container containing N-methylpyrrolidone, stir and mix, then add 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride, react, and heat to obtain composite resin.

2. The nano-ceramic ultra-high hardness powder coating according to claim 1, characterized in that, In Q1, the ratio of 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, lauryl methacrylate, 3-mercaptopropyltriethoxysilane, azobisisobutyronitrile, and tetrahydrofuran is (3.88-4.12) g : (4.12-5.35) g : (1.01-1.39) g : (0.01-0.03) g : (10-20) mL.

3. The nano-ceramic ultra-high hardness powder coating according to claim 1, characterized in that, In Q2, the ratio of γ-glycidyl etheroxypropyltrimethoxysilane to colorless transparent liquid 1 is (21.12-25.45) g : (8.72-9.32) g.

4. The nano-ceramic ultra-high hardness powder coating according to claim 1, characterized in that, In S1, the ratio of 2-chloro-5-nitrobenzaldehyde, 4,4'-difluorobenzoyl, ammonium acetate and acetic acid is (1.483-2.048) g : (2.122-2.894) g : (5.121-5.483) g : (25-35) mL.

5. The nano-ceramic ultra-high hardness powder coating according to claim 1, characterized in that, In S2, the ratio of organic compound a, potassium carbonate, p-nitrophenol and N,N-dimethylformamide is (4.88-5.32) g : (1.988-2.046) g : (1.923-2.114) g : (48-52) mL.

6. The nano-ceramic ultra-high hardness powder coating according to claim 1, characterized in that, In S3, the ratio of organic compound b, ethanol, Pd / C and hydrazine hydrate is (5.48-6.41) g : (125-178) mL : (0.532-0.688) g : (23-28) mL.

7. The nano-ceramic ultra-high hardness powder coating according to claim 1, characterized in that, In S4, the ratio of organic compound c, N-methylpyrrolidone and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride is (2.12-2.78) g : (20-30) mL : (4.23-4.66) g.

8. A method for preparing a nano-ceramic ultra-high hardness powder coating as described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Add alumina, zirconium oxide, silicon carbide and titanium dioxide to a vacuum drying oven in sequence and dry. Then dilute the coupling agent with anhydrous ethanol, spray it on the surface of the pretreated powder, mix and stir to obtain the pretreated powder. Step 2: Mix and stir the composite organic additive, composite resin, dispersant and leveling agent to obtain a composite mixed additive; Step 3: Add the pretreated powder and composite additives to a container, mix, melt extrude, plasticize, cool, pulverize, and sieve to obtain a nano-ceramic ultra-high hardness powder coating.

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