Inorganic copolymer anticorrosive coating and preparation method thereof

Abstract

The application discloses an inorganic copolymer anticorrosive paint and a preparation method thereof, and relates to the technical field of paints. The inorganic copolymer anticorrosive paint comprises the following raw materials in parts by weight: 20-30 parts of silica sol, 8-15 parts of sodium hydroxide, 30-45 parts of metakaolin, 8-20 parts of quartz sand, 15-25 parts of water, 0.3-2 parts of sodium polyacrylate, 0.2-3 parts of polydimethylsiloxane emulsion, 5-12 parts of modified nanometer titanium dioxide, 6-10 parts of modified epoxy resin, 10-25 parts of hydroxyethyl methacrylate, 5-10 parts of zinc phosphate, 3-8 parts of aluminum tripolyphosphate and 2-6 parts of red iron oxide. The inorganic copolymer anticorrosive paint has scientific raw material proportioning, and the anticorrosive performance is enhanced through the modified nanometer titanium dioxide and the epoxy resin. In the preparation, step-by-step feeding and ultrasonic dispersion are adopted to ensure that the materials are uniform, and vacuum degassing and nitrogen protection are adopted to improve the stability. The silica sol, the zinc phosphate and other components have a synergistic effect, a dense coating is formed, the anticorrosive performance is high, the construction performance is good, and the inorganic copolymer anticorrosive paint is suitable for various scenes.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to an inorganic copolymer anticorrosive coating and its preparation method. Background Technology

[0002] In the industrial sector, metallic materials are widely used in construction, shipbuilding, and chemical equipment due to their excellent mechanical properties. However, metal corrosion remains a key factor limiting their service life. Statistics show that global economic losses due to metal corrosion account for 2%-4% of GDP annually. Furthermore, equipment failures caused by corrosion can lead to safety accidents and environmental pollution.

[0003] Traditional anti-corrosion coatings are mostly based on organic polymers. While they offer some corrosion protection, they suffer from poor temperature resistance and are prone to aging, resulting in a significantly shortened service life in harsh environments such as high temperatures, high humidity, and strong acids and alkalis. Inorganic coatings, on the other hand, are gaining attention due to their advantages such as high temperature resistance, chemical corrosion resistance, and environmental friendliness with no volatile organic compounds. However, existing inorganic coatings generally suffer from poor film-forming properties, insufficient flexibility, and susceptibility to cracking, limiting their application range.

[0004] Currently, most inorganic anti-corrosion coatings on the market rely on single inorganic binders, such as silica sol and phosphates, resulting in insufficient coating density and easy penetration by moisture and corrosive media. Simultaneously, the poor compatibility between inorganic fillers and the base material easily leads to uneven dispersion and sedimentation, resulting in unstable coating performance. Furthermore, existing preparation processes lack sufficient control over raw material pretreatment and dispersion, making it difficult to ensure sufficient reaction of the coating components, thus affecting the crosslinking density and anti-corrosion performance of the coating.

[0005] With increasingly stringent environmental protection requirements and more complex industrial environments, there is an urgent need to develop a new type of inorganic anti-corrosion coating that combines excellent anti-corrosion performance, environmental friendliness, and construction stability. This would address the shortcomings of traditional coatings in terms of corrosion resistance, durability, and environmental friendliness, and meet the demand for long-term anti-corrosion in high-end industrial sectors. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an inorganic copolymer anti-corrosion coating and its preparation method, which solves the problems of poor temperature resistance, easy aging and cracking, easy media penetration, and uneven and unstable dispersion of traditional coatings.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An inorganic copolymer anti-corrosion coating comprises the following raw materials in parts by weight: 20-30 parts silica sol, 8-15 parts sodium hydroxide, 30-45 parts metakaolin, 8-20 parts quartz sand, 15-25 parts water, 0.3-2 parts sodium polyacrylate, 0.2-3 parts polydimethylsiloxane emulsion, 5-12 parts modified nano titanium dioxide, 6-10 parts modified epoxy resin, 10-25 parts hydroxyethyl methacrylate, 5-10 parts zinc phosphate, 3-8 parts aluminum tripolyphosphate, and 2-6 parts iron oxide red.

[0009] Furthermore, the silica sol has a solid content of 25%-35% to ensure bonding strength, and a pH value of 9-10 to provide a suitable alkaline environment for the inorganic reaction; the quartz sand has a particle size of 40-80 mesh and is calcined at 800-1000℃ for 2-3 hours before cooling for later use. Calcination removes impurities and moisture, increases hardness and facilitates dispersion, and enhances the wear resistance and density of the coating; the sodium hydroxide is of analytical grade with a purity ≥96% to avoid impurity interference, ensure pH stability of the system, and ensure uniform formation of the inorganic network.

[0010] Furthermore, the modified nano-titanium dioxide is prepared using the following specific steps:

[0011] A1. Add nano-titanium dioxide to anhydrous ethanol and ultrasonically disperse it at 300-400W for 30-40 minutes to ensure uniform suspension of nano-titanium dioxide; then add silane coupling agent KH-550, heat to 80-90℃, and stir at 200-300r / min for 4-6 hours; after the reaction is complete, centrifuge the mixture at 3000-4000r / min for 15-20 minutes, wash the precipitate 3-4 times with anhydrous ethanol, and dry at 60-70℃ for 8-10 hours to obtain the first modified product;

[0012] The alkoxy groups in the silane coupling agent KH-550 undergo a hydrolytic condensation reaction with the hydroxyl groups on the surface of nano-titanium dioxide, forming stable Si-O-Ti chemical bonds and introducing organic amine groups into the surface of the nanoparticles. This process breaks the agglomeration tendency of nano-titanium dioxide and improves its interfacial compatibility with subsequent organic matrix materials through organic groups, laying the foundation for subsequent composites.

[0013] A2. Take the first modified product and add it to toluene. Disperse it ultrasonically at 250-350W for 20-30 minutes. Then add maleic anhydride and benzoyl peroxide. Reflux at 110-120℃ for 6-8 hours. After the reaction is complete, transfer the product to a separatory funnel and wash it 3-5 times with a toluene and ethanol mixture (volume ratio 3:1). Dry it at 80-90℃ for 8-10 hours. Add dichloromethane to the dried product and disperse it ultrasonically for 10-15 minutes. Then add nano-montmorillonite and stir at 300-400r / min at 50-60℃ for 3-4 hours. Filter and wash the residue with dichloromethane. Dry it at 80-90℃ for 2-4 hours to obtain the second modified product.

[0014] Initiated by benzoyl peroxide, maleic anhydride reacts with the amine group introduced in the first step to graft a polar group containing carboxyl groups, further enhancing the chemical bonding force between the nanoparticles and the resin. Subsequently, nano-montmorillonite is added and combines with nano-titanium dioxide through interlayer forces. The layered structure of montmorillonite constructs a physical barrier network, which can delay the penetration path of corrosive media such as water and chloride ions, while improving the dispersion stability of nanoparticles in the system.

[0015] A3. Disperse the secondary modified product in dimethylformamide, sonicate at 200-300W for 15-20 min, add polyvinylpyrrolidone, and stir at 200-300 r / min at 30-40℃ for 6-8 h. After the reaction is complete, add 10% sodium silicate aqueous solution by mass, continue stirring for 2-3 h, then add hollow glass microspheres with a particle size of 20 μm, stir evenly, wash the product with a mixed solution of dimethylformamide and water at a volume ratio of 4:1, and dry at 50-60℃ for 6-8 h to obtain modified nano titanium dioxide.

[0016] Polyvinylpyrrolidone forms steric hindrance on the surface of nanoparticles through adsorption, preventing sedimentation and aggregation during storage; the silicon-oxygen bonds provided by sodium silicate aqueous solution react with inorganic components such as nano-titanium dioxide surface and silica sol, enhancing the continuity of the inorganic network; 20μm hollow glass microspheres fill the pores of the coating, reducing defects and increasing the physical barrier effect, ultimately achieving a synergistic improvement in the "compatibility-dispersion-barrier" properties of nanoparticles.

[0017] Furthermore, the ratio of the amount of nano-titanium dioxide, anhydrous ethanol, and silane coupling agent KH-550 is 500-600g: 800-1000mL: 30-40mL.

[0018] Furthermore, the ratio of the first modified product, toluene, maleic anhydride, benzoyl peroxide, dichloromethane, and nano-montmorillonite in A2 is 200-300g: 500-700mL: 20-30g: 10-15g: 150-250mL: 5-10g.

[0019] Furthermore, the ratio of the secondary modified product, dimethylformamide, polyvinylpyrrolidone, sodium silicate aqueous solution, and hollow glass microspheres in A3 is 150-250g: 400-600mL: 15-25g: 50-80mL: 10-15g.

[0020] Furthermore, the modified epoxy resin is prepared using the following specific steps:

[0021] B1. Dissolve epoxy resin in ethylene glycol monobutyl ether and stir at 200-300 r / min until dissolved. Add polyetheramine D230 and heat to 50-60℃ for 3-5 h. After the reaction is complete, pour the mixture into a rotary evaporator and remove ethylene glycol monobutyl ether by rotary evaporation at 60-70℃ and a vacuum of 0.05-0.07 MPa to obtain the preliminary modified epoxy resin.

[0022] The amino group of polyetheramine D230 undergoes a ring-opening reaction with the epoxy group of the epoxy resin, introducing flexible polyether segments into the epoxy resin molecular chain. This process reduces the brittleness of the epoxy resin, alleviates stress concentration through the deformation of the flexible segments, and provides basic flexibility for the coating.

[0023] B2. Cool the pre-modified epoxy resin to 30-40℃, add multi-walled carbon nanotubes that have undergone surface acidification treatment, and ultrasonically disperse at 350-450W for 30-40 minutes. Then, stir and react at 60-70℃ and 300-400r / min for 4-6 hours. After the reaction is completed, add nano-silica aerogel and continue stirring for 2-3 hours to ensure uniform dispersion, thus obtaining the second-modified epoxy resin.

[0024] The surface of multi-walled carbon nanotubes treated with a mixture of concentrated nitric acid and concentrated sulfuric acid introduces carboxyl and hydroxyl groups, which can chemically react with the hydroxyl and epoxy groups of epoxy resin to achieve "molecular-level bonding". The one-dimensional nanostructure of carbon nanotubes constructs a three-dimensional reinforcing network, which significantly improves the tensile strength and impact resistance of the resin. The subsequently added nano-silica aerogel, due to its high specific surface area and porous structure, can adsorb corrosive media and reduce thermal conductivity, while filling the resin gaps and enhancing the density of the coating.

[0025] B3. Add glycidyl methacrylate and azobisisobutyronitrile to the second modified system, purge the air with nitrogen gas to maintain a nitrogen flow rate of 50-80 mL / min, heat the reaction apparatus to 80-90℃, and react for 5-7 h. After the reaction is completed, cool to room temperature, add hydroxyl-terminated hyperbranched polyester, and stir at 200-300 r / min at 40-50℃ for 3-4 h to obtain the final modified epoxy resin.

[0026] Glycidyl methacrylate undergoes polymerization with epoxy resin segments under the initiation of azobisisobutyronitrile, introducing more epoxy groups and increasing the density of crosslinking sites. After nitrogen protection, a denser three-dimensional network structure is formed. The polyhydroxyl groups of the terminal hydroxyl hyperbranched polyester react with epoxy groups to increase the branching degree of the molecular chain, further disperse stress and improve the adhesion between the coating and the substrate, ultimately achieving synergistic optimization of epoxy resin in terms of "flexibility, mechanical strength and corrosion resistance".

[0027] Furthermore, the ratio of epoxy resin, ethylene glycol monobutyl ether, and polyetheramine D230 in B1 is 400-500g: 600-800mL: 30-40g.

[0028] Furthermore, the ratio of surface-acidified multi-walled carbon nanotubes to nano-silica aerogels in B2 is 20-30g:10-15g.

[0029] Furthermore, the ratio of glycidyl methacrylate, azobisisobutyronitrile, and hydroxyl-terminated hyperbranched polyester in B3 is 15-25g: 5-10g: 20-30g.

[0030] Furthermore, the multi-walled carbon nanotubes in B2 undergo surface acidification treatment. The specific method of acidification treatment is as follows: the multi-walled carbon nanotubes are added to a mixture of concentrated nitric acid and concentrated sulfuric acid at a volume ratio of 1:3, refluxed and stirred at 70°C for 4 hours, then filtered, washed with water until neutral, and dried. The synergistic effect of concentrated nitric acid and concentrated sulfuric acid efficiently introduces active groups such as carboxyl and hydroxyl groups onto the surface of the carbon nanotubes, significantly improving their compatibility and interfacial bonding with epoxy resin, and enhancing the mechanical properties of the coating.

[0031] A method for preparing an inorganic copolymer anticorrosive coating specifically includes the following steps:

[0032] S1. Inject 20-30 parts of silica sol into a stirred tank, then add 8-15 parts of sodium hydroxide and 15-25 parts of water. Set the stirring speed to 600-800 r / min and continue stirring and mixing for 20-30 hours to ensure no precipitation or stratification occurs, and obtain a uniform premixed solution. Ensure that the silica sol and sodium hydroxide react fully to form a uniform inorganic precursor solution, laying the foundation for subsequent network structure construction.

[0033] S2. Transfer the above premixed solution to a high-speed mixer, turn on the mixer, set the speed to 500-600 r / min, and add 30-45 parts of metakaolin in two batches. Stir for 5-10 minutes after each addition before adding the next batch. After all the materials have been added, continue stirring for 30-40 minutes. This step-by-step addition and stirring helps to prevent the metakaolin from agglomerating and ensures that it is evenly dispersed in the premixed solution, thereby improving the uniformity and density of the inorganic network structure.

[0034] S3. Maintain the stirring speed at 400-500 r / min, add 5-12 parts of modified nano titanium dioxide, and stir for 15-20 min; then add 6-10 parts of modified epoxy resin, and continue stirring for 20-25 min; then add 10-25 parts of hydroxyethyl methacrylate, and stir for 10-15 min; subsequently add 5-10 parts of zinc phosphate, 3-8 parts of aluminum tripolyphosphate, and 2-6 parts of iron oxide red, stirring for 10-12 min after each addition; then add 8-20 parts of quartz sand, and stir for 20-25 min; finally add 0.3-2 parts of sodium polyacrylate and 0.2-3 parts of polydimethylsiloxane emulsion, and continue stirring for 1-2 h. Before each addition of raw material, ensure that the previous raw material is completely dispersed to avoid agglomeration; use variable speed stirring to adapt to the characteristics of different raw materials, ensuring uniform dispersion of nanoparticles, fillers, and additives, and avoiding coating performance fluctuations caused by agglomeration; confirm the dispersion state step by step to ensure thorough mixing of each component and improve the storage stability of the coating;

[0035] S4. After stirring, let the material stand for 5-10 minutes, then filter the material using a 200-300 mesh filter. During the filtration process, slowly push the material with a scraper to ensure thorough filtration. The filtered coating needs to undergo vacuum degassing treatment. The degassing pressure is -0.08 to -0.09 MPa, and the degassing time is 15-20 minutes to obtain an inorganic copolymer anti-corrosion coating. Filtration removes large particulate impurities to ensure the fineness of the coating and its leveling properties during application. Vacuum degassing eliminates internal air bubbles to avoid defects such as pinholes and shrinkage cavities after film formation.

[0036] Furthermore, the settling process in S4 must be carried out in a sealed mixing tank, and nitrogen gas is introduced during the settling period to prevent excessive contact between the material and air, maintain the chemical stability of the coating, extend the storage period, and ensure consistent application performance.

[0037] This invention provides an inorganic copolymer anticorrosive coating and its preparation method, which has the following beneficial effects:

[0038] 1. This invention utilizes the synergistic effect of modified nano-titanium dioxide, modified epoxy resin, zinc phosphate, and aluminum tripolyphosphate to form a dense dual-protection system of physical barrier and chemical passivation within the coating. After multiple modifications, including silane coupling agents and maleic anhydride, the modified nano-titanium dioxide exhibits significantly improved compatibility with the base material, uniformly filling the coating pores and preventing the penetration of corrosive media such as moisture and chloride ions. Zinc phosphate and aluminum tripolyphosphate form a passivation film on the metal surface, inhibiting electrochemical corrosion reactions. Furthermore, the organic-inorganic interpenetrating network structure formed by the modified epoxy resin and silica sol further enhances the adhesion between the coating and the substrate, effectively resisting corrosion and erosion under harsh environments such as long-term immersion and alternating wet and dry conditions, significantly extending the coating's service life.

[0039] 2. The scientific ratio of inorganic and organic components in the coating system achieves a balance in mechanical properties. Silica sol and metakaolin form a rigid inorganic network structure during the reaction, endowing the coating with excellent hardness and high-temperature resistance. Modified epoxy resin, after modification with multi-walled carbon nanotubes and terminally hydroxyl hyperbranched polyester, exhibits enhanced molecular chain flexibility, effectively alleviating stress concentration under thermal cycling and mechanical impact, thus avoiding the cracking defects common in traditional inorganic coatings. The introduction of polydimethylsiloxane emulsion reduces the surface friction coefficient of the coating, improving wear resistance and impact resistance, enabling the coating to withstand mechanical wear in industrial environments while adapting to the micro-deformation of the substrate, reducing coating peeling caused by substrate expansion and contraction.

[0040] 3. Through refined preparation processes and synergistic use of additives, the stability of the coating is ensured throughout the entire process of storage, application, and film formation. The preparation process involves step-by-step feeding combined with ultrasonic dispersion and high-speed stirring to ensure uniform dispersion of solid particles such as modified nano-titanium dioxide and quartz sand, preventing agglomeration. Sodium polyacrylate, as a dispersant, effectively prevents raw material sedimentation and extends shelf life. Vacuum degassing and nitrogen protection processes reduce internal air bubbles in the coating, resulting in a more uniform film formation during application, free from defects such as pinholes and shrinkage cavities. Polydimethylsiloxane emulsion reduces the surface tension of the coating and improves leveling properties, enabling the coating to form a continuous and complete film on various substrates such as metal and concrete, ensuring the consistency and reliability of the coating performance after application.

[0041] 4. The coating is primarily composed of inorganic components, supplemented with low-toxicity and highly efficient organic additives, significantly reducing VOC emissions and meeting environmental protection requirements. Simultaneously, due to its inorganic network structure and modified components, the coating exhibits excellent high-temperature resistance and chemical corrosion resistance: the inorganic skeleton formed by silica sol and metakaolin can withstand high temperatures without decomposition, and the modified epoxy resin enhances resistance to acid and alkali media erosion, making it suitable for various harsh environments such as high-temperature equipment, chemical pipelines, and marine engineering. Furthermore, the coating does not exhibit stratification or sedimentation during storage, and it is highly adaptable to environmental temperature and humidity during application, meeting coating needs under different working conditions and significantly broadening the application range of anti-corrosion coatings. Detailed Implementation

[0042] 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.

[0043] Example 1: Preparation of an inorganic copolymer anti-corrosion coating. The specific preparation steps are as follows:

[0044] S1. Pour 20 parts of silica sol into a stirring vessel, then add 8 parts of sodium hydroxide and 15 parts of water. Set the stirring speed to 600 r / min and continue stirring and mixing for 20 hours to ensure no precipitation or stratification, and obtain a uniform premixed solution.

[0045] S2. Transfer the above premixed solution to a high-speed mixer, turn on the mixer, set the speed to 500 r / min, add 30 parts of metakaolin in two batches, stir for 5 minutes after each addition, and continue stirring for 30 minutes after all the materials have been added.

[0046] S3. Maintain the stirring speed at 400 r / min, add 6 parts of epoxy resin, and stir for 20 min; then add 10 parts of hydroxyethyl methacrylate and stir for 10 min; subsequently add 5 parts of zinc phosphate, 3 parts of aluminum tripolyphosphate, and 2 parts of iron oxide red in sequence, stirring for 10 min after each addition; then add 8 parts of quartz sand and stir for 20 min; finally add 0.3 parts of sodium polyacrylate and 0.2 parts of polydimethylsiloxane emulsion, and continue stirring for 1 h. Before each addition of raw material, ensure that the previous raw material has been completely dispersed to avoid agglomeration.

[0047] S4. After stirring, let the material stand for 5 minutes, then filter the material using a 200-mesh filter. During the filtration process, use a scraper to slowly push the material to ensure thorough filtration. The filtered coating needs to be vacuum degassed at a pressure of -0.08 MPa for 15 minutes to obtain the inorganic copolymer anticorrosive coating.

[0048] Example 2: Preparation of inorganic copolymer anti-corrosion coating. The specific preparation steps are as follows:

[0049] S1. Inject 30 parts of silica sol into a stirred tank, then add 15 parts of sodium hydroxide and 25 parts of water. Set the stirring speed to 800 r / min and continue stirring and mixing for 30 hours to ensure no precipitation or stratification, and obtain a uniform premixed solution.

[0050] S2. Transfer the above premixed solution to a high-speed mixer, turn on the mixer, set the speed to 600 r / min, add 45 parts of metakaolin in two batches, stir for 10 minutes after each addition, and continue stirring for 40 minutes after all the materials have been added.

[0051] S3. Keep the stirring equipment speed at 500 r / min, add 10 parts of epoxy resin, and stir for 25 min; then add 25 parts of hydroxyethyl methacrylate and stir for 15 min; then add 10 parts of zinc phosphate, 8 parts of aluminum tripolyphosphate, and 6 parts of iron oxide red in sequence, stirring for 12 min after each addition; then add 20 parts of quartz sand and stir for 25 min; finally add 2 parts of sodium polyacrylate and 3 parts of polydimethylsiloxane emulsion, and continue stirring for 2 h. Before each addition of raw materials, it is necessary to confirm that the previous raw material has been completely dispersed to avoid agglomeration.

[0052] S4. After stirring, let the material stand for 10 minutes, then filter the material using a 300-mesh filter. During the filtration process, use a scraper to slowly push the material to ensure thorough filtration. The filtered coating needs to be vacuum degassed at a pressure of -0.09 MPa for 20 minutes to obtain the inorganic copolymer anticorrosive coating.

[0053] Example 3: Preparation of an inorganic copolymer anti-corrosion coating. The specific preparation steps are as follows:

[0054] S1. Pour 25 parts of silica sol into a stirred tank, then add 11 parts of sodium hydroxide and 20 parts of water. Set the stirring speed to 700 r / min and continue stirring and mixing for 25 hours to ensure no precipitation or stratification, and obtain a uniform premixed solution.

[0055] S2. Transfer the above premixed solution to a high-speed mixer, turn on the mixer, set the speed to 550 r / min, add 38 parts of metakaolin in two batches, stir for 7 minutes after each addition, and continue stirring for 35 minutes after all the materials have been added.

[0056] S3. Maintain the stirring speed at 450 r / min, add 8 parts of epoxy resin, and stir for 22 min; then add 17 parts of hydroxyethyl methacrylate and stir for 12 min; subsequently add 7 parts of zinc phosphate, 5 parts of aluminum tripolyphosphate, and 4 parts of iron oxide red in sequence, stirring for 11 min after each addition; then add 14 parts of quartz sand and stir for 22 min; finally add 1 part of sodium polyacrylate and 1 part of polydimethylsiloxane emulsion, and continue stirring for 1.5 h. Before each addition of raw material, it is necessary to confirm that the previous raw material has been completely dispersed to avoid agglomeration.

[0057] S4. After stirring, let the material stand for 7 minutes, then filter the material using a 250-mesh filter. During the filtration process, use a scraper to slowly push the material to ensure thorough filtration. The filtered coating needs to be vacuum degassed at a pressure of -0.08 MPa for 17 minutes to obtain the inorganic copolymer anti-corrosion coating.

[0058] Example 4: Preparation of modified nano-titanium dioxide. The specific preparation steps are as follows:

[0059] A1. Add 500g of nano-titanium dioxide to 800mL of anhydrous ethanol and sonicate at 300W for 30min to suspend the nano-titanium dioxide uniformly. Then add 30mL of silane coupling agent KH-550, heat to 80℃, and stir at 200r / min for 4h. After the reaction is completed, centrifuge the mixture at 3000r / min for 15min, wash the precipitate three times with anhydrous ethanol, and dry at 60℃ for 8h to obtain the first modified product.

[0060] A2. Take 200g of the first modified product and add it to 500mL of toluene. Disperse it by ultrasonication at 250W for 20min. Then add 20g of maleic anhydride and 10g of benzoyl peroxide. Reflux at 110℃ for 6h. After the reaction is complete, transfer the product to a separatory funnel and wash it three times with a toluene and ethanol mixture at a volume ratio of 3:1. Dry it at 80℃ for 8h. Add 150mL of dichloromethane to the dried product and disperse it by ultrasonication for 10min. Then add 5g of nano-montmorillonite and stir at 300r / min at 50℃ for 3h. Filter and wash the residue with dichloromethane. Dry at 80℃ for 2h to obtain the second modified product.

[0061] A3. Take 150g of the secondary modified product and disperse it in 400mL of dimethylformamide. Sonicate at 200W for 15min. Add 15g of polyvinylpyrrolidone and stir at 200r / min at 30℃ for 6h. After the reaction is completed, add 50mL of 10% sodium silicate aqueous solution and continue stirring for 2h. Then add 10g of hollow glass microspheres with a particle size of 20μm and stir evenly. Wash the product with a mixed solution of dimethylformamide and water with a volume ratio of 4:1 and dry at 50℃ for 6h to obtain modified nano titanium dioxide.

[0062] Example 5: Preparation of modified nano-titanium dioxide. The specific preparation steps are as follows:

[0063] A1. Add 600g of nano-titanium dioxide to 1000mL of anhydrous ethanol and disperse it by ultrasonication at 400W for 30-40min to ensure uniform suspension of nano-titanium dioxide; then add 40mL of silane coupling agent KH-550, heat to 90℃, and stir at 300r / min for 6h; after the reaction is completed, centrifuge the mixture at 4000r / min for 20min, wash the precipitate 4 times with anhydrous ethanol, and dry at 70℃ for 10h to obtain the first modified product;

[0064] A2. Take 300g of the first modified product and add it to 700mL of toluene. Disperse it by ultrasonication at 350W for 30min. Then add 30g of maleic anhydride and 15g of benzoyl peroxide. Reflux at 120℃ for 8h. After the reaction is complete, transfer the product to a separatory funnel and wash it 5 times with a toluene and ethanol mixture at a volume ratio of 3:1. Dry it at 90℃ for 10h. Add 250mL of dichloromethane to the dried product and disperse it by ultrasonication for 15min. Then add 10g of nano-montmorillonite and stir at 400r / min at 60℃ for 4h. Filter and wash the filter residue with dichloromethane. Dry it at 90℃ for 4h to obtain the second modified product.

[0065] A3. Take 250g of the secondary modified product and disperse it in 600mL of dimethylformamide. Sonicate at 300W for 20min. Add 25g of polyvinylpyrrolidone and stir at 300r / min at 40℃ for 8h. After the reaction is completed, add 80mL of 10% sodium silicate aqueous solution and continue stirring for 3h. Then add 15g of hollow glass microspheres with a particle size of 20μm and stir evenly. Wash the product with a mixed solution of dimethylformamide and water with a volume ratio of 4:1 and dry at 60℃ for 8h to obtain modified nano titanium dioxide.

[0066] Example 6: Preparation of modified epoxy resin. The specific preparation steps are as follows:

[0067] B1. Dissolve 400g of epoxy resin in 600mL of ethylene glycol monobutyl ether, stir at 200r / min until dissolved, add 30g of polyetheramine D230, heat to 50℃ and react for 3h; after the reaction is completed, pour the mixture into a rotary evaporator, and remove the ethylene glycol monobutyl ether by rotary evaporation at 60℃ and a vacuum of 0.05MPa to obtain the preliminary modified epoxy resin;

[0068] B2. Cool the pre-modified epoxy resin to 30°C, add 20g of surface-acidified multi-walled carbon nanotubes, ultrasonically disperse at 350W for 30min, and then stir at 300r / min at 60°C for 4h. After the reaction is complete, add 10g of nano silica aerogel and continue stirring for 2h to make it uniformly dispersed to obtain the second modified epoxy resin.

[0069] B3. Add 15g glycidyl methacrylate and 5g azobisisobutyronitrile to the second modified system, purge the air with nitrogen gas and keep the nitrogen flow rate at 50mL / min, heat the reaction apparatus to 80℃ and react for 5h; after the reaction is completed, cool to room temperature, add 20g of hydroxyl-terminated hyperbranched polyester, and stir at 200r / min at 40℃ for 3h to obtain the final modified epoxy resin.

[0070] Example 7: Preparation of modified epoxy resin. The specific preparation steps are as follows:

[0071] B1. Dissolve 500g of epoxy resin in 800mL of ethylene glycol monobutyl ether, stir at 300r / min until dissolved, add 40g of polyetheramine D230, heat to 60℃ and react for 5h; after the reaction is completed, pour the mixture into a rotary evaporator, and remove the ethylene glycol monobutyl ether by rotary evaporation at 70℃ and a vacuum of 0.07MPa to obtain the preliminary modified epoxy resin.

[0072] B2. Cool the pre-modified epoxy resin to 40°C, add 30g of surface-acidified multi-walled carbon nanotubes, ultrasonically disperse at 450W for 40min, and then stir at 70°C at 400r / min for 6h. After the reaction is complete, add 15g of nano silica aerogel and continue stirring for 3h to make it uniformly dispersed to obtain the second modified epoxy resin.

[0073] B3. Add 25g glycidyl methacrylate and 10g azobisisobutyronitrile to the second modified system, purge the air with nitrogen gas and keep the nitrogen flow rate at 80mL / min, heat the reaction apparatus to 90℃ and react for 7h; after the reaction is completed, cool to room temperature, add 30g of hydroxyl-terminated hyperbranched polyester, stir at 300r / min at 50℃ for 4h to obtain the final modified epoxy resin.

[0074] Comparative Example 1: An inorganic copolymer anti-corrosion coating was prepared. The specific preparation steps are as follows:

[0075] The remaining steps remain unchanged, except that 8 parts of the modified nano-titanium dioxide prepared in Example 4 are first added to S3 of Example 3, stirred for 17 minutes, and then the subsequent operations are continued to prepare the inorganic copolymer anti-corrosion coating.

[0076] Comparative Example 2: An inorganic copolymer anti-corrosion coating was prepared. The specific preparation steps are as follows:

[0077] The remaining steps remain unchanged, except that the epoxy resin in Example 3 is replaced with the modified epoxy resin prepared in Example 7 to prepare an inorganic copolymer anti-corrosion coating.

[0078] Comparative Example 3: An inorganic copolymer anti-corrosion coating was prepared. The specific preparation steps are as follows:

[0079] The remaining steps remain unchanged. First, add 8 parts of the modified nano-titanium dioxide prepared in Example 4 to S3 of Example 3, stir for 17 min, then replace the epoxy resin with the modified epoxy resin prepared in Example 7 and continue the subsequent operations to prepare the inorganic copolymer anti-corrosion coating.

[0080] Performance testing

[0081] Test Project Test standards / methods Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Resistance to neutral salt spray GB / T1771-2007 Corrosion grade Ri4 Corrosion grade Ri3 Corrosion grade Ri3 Corrosion grade Ri2 Corrosion grade Ri1 Corrosion grade Ri0 Adhesion (cross-cut test) GB / T9286-2021 Level 3 Level 3 Level 2 Level 2 Level 1 Level 0 Pencil hardness GB / T6739-2022 H H 2H 2H 2H 3H Heat resistance (continuous test in a constant temperature chamber for 1000 hours) GB / T1735-2009 After testing at 150℃, the coating surface turned yellow, grade 3, and the adhesion dropped to grade 4. After testing at 150℃, the coating showed slight yellowing, grade 2, and adhesion decreased to grade 3. After testing at 180℃, the coating showed slight yellowing, grade 2; adhesion showed no significant change, remaining at grade 2. After testing at 200℃, the coating showed no yellowing, achieving grade 1; the adhesion showed no significant change, remaining at grade 2. After testing at 200℃, the coating showed no yellowing, maintaining a grade of 1; adhesion also showed no significant change, remaining at grade 1. After testing at 250℃, the coating showed no yellowing, achieving a grade of 0; adhesion also showed no significant change, remaining at grade 0. <![CDATA[Acid resistance (5% H2SO4, 72 h)]]> GB / T9274-1988 Weight loss 5.2% Weight loss 4.8% Weight loss 4.5% Weight loss 1.8% Weight loss 2.2% Weight loss 0.5% Storage stability (3 months) Let stand and observe whether it separates into layers / sediments. Slight stratification Slight sedimentation Small amount of sediment No layering / precipitation No layering / precipitation No layering / precipitation

[0082] According to the performance test results, the inorganic copolymer anticorrosive coatings of the examples and comparative examples showed significant differences in several properties: In terms of neutral salt spray resistance, the corrosion grade Ri0 of Comparative Example 3, which added modified nano-titanium dioxide and modified epoxy resin, was far superior to that of Examples 1-3 and Comparative Examples 1-2, which added only the modified components; In terms of adhesion, Comparative Example 3 achieved the best grade of 0, Examples 1-2 achieved grade 3, and Comparative Example 2 achieved grade 1; In terms of pencil hardness, Comparative Example 3 achieved 3H, Examples 1-2 achieved H, and the rest achieved 2H; In terms of heat resistance, Comparative Examples 1-3 could withstand 200-250℃ without change, which was better than the yellowing phenomenon of Examples 1-3 at 150-180℃; In terms of acid resistance, the weight loss rate of Comparative Example 3 was only 0.5%, which was significantly lower than the 4.5%-5.2% of the examples and the 1.8%-2.2% of Comparative Examples 1-2; In terms of storage stability, Comparative Examples 1-3 showed no stratification / precipitation, while Examples 1-3 showed slight stratification or precipitation. Overall, Comparative Example 3, which simultaneously added modified nano-titanium dioxide and modified epoxy resin, showed the best performance in all aspects, highlighting the significant improvement in the overall performance of the coating due to the synergistic effect of the two modifying components.

[0083] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. An inorganic copolymer anticorrosive coating, characterized in that: It contains the following raw materials in parts by weight: 20-30 parts silica sol, 8-15 parts sodium hydroxide, 30-45 parts metakaolin, 8-20 parts quartz sand, 15-25 parts water, 0.3-2 parts sodium polyacrylate, 0.2-3 parts polydimethylsiloxane emulsion, 5-12 parts modified nano titanium dioxide, 6-10 parts modified epoxy resin, 10-25 parts hydroxyethyl methacrylate, 5-10 parts zinc phosphate, 3-8 parts aluminum tripolyphosphate, and 2-6 parts iron oxide red; The modified nano-titanium dioxide is prepared using the following specific steps: A1. Add nano-titanium dioxide to anhydrous ethanol and ultrasonically disperse it at 300-400W for 30-40 minutes to ensure uniform suspension of nano-titanium dioxide; then add silane coupling agent KH-550, heat to 80-90℃, and stir at 200-300r / min for 4-6 hours; after the reaction is complete, centrifuge the mixture at 3000-4000r / min for 15-20 minutes, wash the precipitate 3-4 times with anhydrous ethanol, and dry at 60-70℃ for 8-10 hours to obtain the first modified product; A2. Take the first modified product and add it to toluene. Disperse it ultrasonically at 250-350W for 20-30 minutes. Then add maleic anhydride and benzoyl peroxide. Reflux at 110-120℃ for 6-8 hours. After the reaction is complete, transfer the product to a separatory funnel and wash it 3-5 times with a toluene and ethanol mixture (volume ratio 3:1). Dry it at 80-90℃ for 8-10 hours. Add dichloromethane to the dried product and disperse it ultrasonically for 10-15 minutes. Then add nano-montmorillonite and stir at 300-400r / min at 50-60℃ for 3-4 hours. Filter and wash the residue with dichloromethane. Dry it at 80-90℃ for 2-4 hours to obtain the second modified product. A3. Disperse the secondary modified product in dimethylformamide, sonicate at 200-300W for 15-20 min, add polyvinylpyrrolidone, and stir at 200-300 r / min at 30-40℃ for 6-8 h. After the reaction is complete, add 10% sodium silicate aqueous solution dropwise, continue stirring for 2-3 h, then add hollow glass microspheres with a particle size of 20 μm, stir evenly, wash the product with a 4:1 volume ratio of dimethylformamide and water, and dry at 50-60℃ for 6-8 h to obtain modified nano titanium dioxide. The modified epoxy resin is prepared using the following specific steps: B1. Dissolve epoxy resin in ethylene glycol monobutyl ether and stir at 200-300 r / min until dissolved. Add polyetheramine D230 and heat to 50-60℃ for 3-5 h. After the reaction is complete, pour the mixture into a rotary evaporator and remove ethylene glycol monobutyl ether by rotary evaporation at 60-70℃ and a vacuum of 0.05-0.07 MPa to obtain the preliminary modified epoxy resin. B2. Cool the pre-modified epoxy resin to 30-40℃, add multi-walled carbon nanotubes that have undergone surface acidification treatment, and ultrasonically disperse at 350-450W for 30-40 minutes. Then, stir and react at 60-70℃ and 300-400r / min for 4-6 hours. After the reaction is completed, add nano-silica aerogel and continue stirring for 2-3 hours to ensure uniform dispersion, thus obtaining the second-modified epoxy resin. B3. Add glycidyl methacrylate and azobisisobutyronitrile to the second modified system, purge the air with nitrogen gas to maintain a nitrogen flow rate of 50-80 mL / min, heat the reaction apparatus to 80-90℃, and react for 5-7 h. After the reaction is completed, cool to room temperature, add hydroxyl-terminated hyperbranched polyester, and stir at 200-300 r / min at 40-50℃ for 3-4 h to obtain the final modified epoxy resin.

2. The inorganic copolymer anticorrosive coating according to claim 1, characterized in that: The silica sol has a solid content of 25%-35% and a pH value of 9-10; the quartz sand has a particle size of 40-80 mesh and is calcined at 800-1000℃ for 2-3 hours and then cooled for later use; the sodium hydroxide is of analytical grade with a purity ≥96%.

3. The inorganic copolymer anticorrosive coating according to claim 1, characterized in that: The ratio of nano-titanium dioxide, anhydrous ethanol, and silane coupling agent KH-550 in A1 is 500-600g: 800-1000mL: 30-40mL. The ratio of the first modified product, toluene, maleic anhydride, benzoyl peroxide, dichloromethane, and nano-montmorillonite in A2 is 200-300g: 500-700mL: 20-30g: 10-15g: 150-250mL: 5-10g; The ratio of the secondary modified product, dimethylformamide, polyvinylpyrrolidone, sodium silicate aqueous solution, and hollow glass microspheres in A3 is 150-250g: 400-600mL: 15-25g: 50-80mL: 10-15g.

4. The inorganic copolymer anticorrosive coating according to claim 1, characterized in that: The ratio of epoxy resin, ethylene glycol monobutyl ether, and polyetheramine D230 in B1 is 400-500g: 600-800mL: 30-40g; The ratio of surface-acidified multi-walled carbon nanotubes to nano-silica aerogels in B2 is 20-30g: 10-15g. The ratio of glycidyl methacrylate, azobisisobutyronitrile, and hydroxyl-terminated hyperbranched polyester in B3 is 15-25g: 5-10g: 20-30g.

5. The inorganic copolymer anticorrosive coating according to claim 1, characterized in that: The multi-walled carbon nanotubes in B2 have undergone surface acidification treatment. The specific method of acidification treatment is as follows: the multi-walled carbon nanotubes are added to a mixed acid of concentrated nitric acid and concentrated sulfuric acid with a volume ratio of 1:3, refluxed and stirred at 70°C for 4 hours, then filtered, washed with water until neutral, and dried.

6. A method for preparing an inorganic copolymer anticorrosive coating according to any one of claims 1-5, characterized in that: Specifically, it includes the following steps: S1. Pour 20-30 parts of silica sol into a stirred tank, then add 8-15 parts of sodium hydroxide and 15-25 parts of water. Set the stirring speed to 600-800 r / min and continue stirring and mixing for 20-30 hours to ensure no precipitation or stratification, and obtain a uniform premixed solution. S2. Transfer the above premixed solution to a high-speed mixer, turn on the mixer, set the speed to 500-600 r / min, add 30-45 parts of metakaolin in two batches, stir for 5-10 minutes after each addition, and continue stirring for 30-40 minutes after all the materials have been added. S3. Maintain the stirring speed at 400-500 r / min, add 5-12 parts of modified nano titanium dioxide, and stir for 15-20 min; then add 6-10 parts of modified epoxy resin, and continue stirring for 20-25 min; then add 10-25 parts of hydroxyethyl methacrylate, and stir for 10-15 min; subsequently add 5-10 parts of zinc phosphate, 3-8 parts of aluminum tripolyphosphate, and 2-6 parts of iron oxide red, stirring for 10-12 min after each addition; then add 8-20 parts of quartz sand, and stir for 20-25 min; finally add 0.3-2 parts of sodium polyacrylate and 0.2-3 parts of polydimethylsiloxane emulsion, and continue stirring for 1-2 h. Before each addition of raw material, ensure that the previous raw material is completely dispersed to avoid agglomeration. S4. After stirring, let the material stand for 5-10 minutes, then filter the material using a 200-300 mesh filter. During the filtration process, use a scraper to slowly push the material to ensure thorough filtration. The filtered coating needs to be degassed under vacuum. The degassed pressure is -0.08 to -0.09 MPa, and the degassed time is 15-20 minutes to obtain the inorganic copolymer anti-corrosion coating.

7. The method for preparing an inorganic copolymer anticorrosive coating according to claim 6, characterized in that: The settling process in S4 must be carried out in a sealed stirred tank, and nitrogen gas must be introduced during the settling period to prevent the material from excessively contacting the air.