Environment-friendly water-based industrial anticorrosive coating and preparation method thereof

Abstract

The present application relates to an environment-friendly water-based industrial anticorrosive coating and a preparation method thereof, and belongs to the technical field of coating. The coating composition comprises chloroether resin emulsion, corrosion inhibition emulsion, barrier agent, slag composite filler, etc. The corrosion inhibition emulsion is prepared by using hexamethylcyclotrisilazane, glycidyl furfuryl ether and 2-furfurylamine in isopropyl alcohol as raw materials and tetramethylammonium hydroxide as catalyst, and then emulsified with deionized water and composite emulsifier after removing isopropyl alcohol. The barrier agent is prepared by modifying the titanium aluminum carbide sheet layer after acid stripping with 3-aminopropyltriethoxysilane. The slag composite filler is prepared by sintering blast furnace slag powder, zeolite powder and potassium dihydrogen phosphate, etching with citric acid, and then modifying with boron nitride and KH-172 silane coupling agent. The coating uses water as the dispersion medium to reduce VOC emissions, and constructs a protective system in multiple dimensions through chemical active corrosion protection, physical layered barrier, dense film formation and interface covalent bonding, and is suitable for harsh corrosion scenes such as industrial heavy-duty corrosion, ships and marine engineering.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to an environmentally friendly water-based industrial anti-corrosion coating and its preparation method. Background Technology

[0002] Traditional solvent-based industrial anti-corrosion coatings use organic solvents as the dispersion medium, releasing large amounts of volatile organic compounds (VOCs), benzene compounds, and heavy metals during production and application. This not only pollutes the atmosphere and induces photochemical fumes but also endangers the health of construction workers. Furthermore, their flammable and explosive properties significantly increase safety risks during storage and construction. Therefore, limiting VOC emissions from solvent-based coatings is forcing the coating industry to transform towards green, environmentally friendly, and low-toxicity products.

[0003] Environmentally friendly water-based coatings use water as the primary dispersion medium, significantly reducing VOC content. They possess core advantages such as being non-toxic, odorless, non-flammable, easy to apply, and simple to process, perfectly meeting the development needs of green coatings in the industrial sector. They have been widely applied in steel structures, machinery, pipeline corrosion protection, and other applications. After years of technological iteration, mainstream water-based coating systems such as water-based acrylic, water-based epoxy, and water-based polyurethane have matured and achieved large-scale application in general civilian and light-duty corrosion protection fields. This has effectively alleviated the environmental pressure on the coating industry and become the mainstream development trend in industrial anti-corrosion coatings.

[0004] Despite the significant advantages of environmentally friendly water-based coatings, their practical applications in heavy-duty industrial corrosion protection, shipbuilding, and marine engineering still suffer from numerous performance defects that are difficult to overcome, severely hindering their widespread use. Firstly, their corrosion resistance is insufficient. Conventional water-based coatings leave behind a large number of hydrophilic groups after film formation, resulting in low film density. Their resistance to salt spray, acids and alkalis, and damp heat is far inferior to solvent-based coatings, leading to a short rust protection period for metal substrates. Secondly, their water resistance and weather resistance are poor. When the coating is immersed in water or exposed to the outdoors for extended periods, problems such as blistering, peeling, and chalking easily occur. Gloss retention and mechanical properties rapidly decline, making long-term protection difficult to achieve.

[0005] Most water-based anti-corrosion coatings currently on the market can only balance environmental friendliness and basic protection, failing to adequately meet the performance requirements of high corrosion resistance and high weather resistance, and are difficult to replace traditional solvent-based heavy-duty anti-corrosion coatings. Therefore, it is necessary to continuously improve and develop new water-based coating components to enhance film performance while retaining the environmental advantages of water-based systems, achieving a balance between environmental protection and high performance. This would make them suitable for heavy-duty industrial corrosion protection, shipbuilding, marine engineering, and other fields, promoting the green and high-performance development of the coating industry. Summary of the Invention

[0006] To address the shortcomings of existing water-based coatings, such as insufficient anti-corrosion performance and poor water and weather resistance, further improvements are needed. This invention provides an environmentally friendly water-based industrial anti-corrosion coating and its preparation method. It involves preparing synergistic components such as corrosion-inhibiting emulsions, barrier agents, and slag composite fillers, which are then compounded with chlorinated ether resin emulsions, amino-terminated hyperbranched polyamide crosslinking agents, composite film-forming aids, functional additives, and synergistic agents to prepare the coating. Using water as the primary dispersion medium significantly reduces VOC emissions. The coating constructs a long-lasting protective system from multiple dimensions, including active chemical corrosion prevention, physical layered barrier, dense film formation, and interfacial covalent bonding. This solves the core defects of traditional water-based anti-corrosion coatings, such as insufficient anti-corrosion performance and poor water and weather resistance, making it suitable for harsh corrosive environments such as heavy-duty industrial corrosion protection, shipbuilding, and marine engineering. The specific technical solution is as follows:

[0007] An environmentally friendly water-based industrial anti-corrosion coating comprises the following raw materials in parts by weight: 40-45 parts of chlorinated ether resin emulsion, 10-14 parts of corrosion inhibitor emulsion, 5-8 parts of barrier agent, 12-16 parts of slag composite filler, 5-7 parts of amino-terminated hyperbranched polyamide crosslinking agent, 2.0-3.5 parts of composite film-forming aid, 1.5-2.0 parts of functional aid, 0.8-1.3 parts of synergistic aid, and the balance being deionized water; The corrosion-inhibiting emulsion was prepared by reacting hexamethylcyclotrisilazane, glycidyl furfuryl ether, and 2-furanylamine in isopropanol with tetramethylammonium hydroxide as a catalyst. After removing the isopropanol, it was emulsified with deionized water and a composite emulsifier. The barrier agent was prepared by modifying acid-exfoliated titanium aluminum carbide sheets with 3-aminopropyltriethoxysilane. The slag composite filler was prepared by sintering blast furnace slag powder, zeolite powder, and potassium dihydrogen phosphate, followed by citric acid etching, and then modification with boron nitride and KH-172 silane coupling agent.

[0008] The preparation of the corrosion-inhibiting emulsion includes: mixing hexamethylcyclotrisilazane, glycidyl furfuryl ether, 2-furanylamine and isopropanol, reacting at 70-75°C under tetramethylammonium hydroxide catalysis until the epoxy value is below 0.01 mol / 100g, removing isopropanol under reduced pressure to obtain the reaction solution, then mixing and shearing emulsifying with deionized water and a composite emulsifier, adjusting the pH to 7.8-8.2 with dimethylethanolamine, and filtering to obtain the final product.

[0009] In the preparation of the corrosion-inhibiting emulsion, the mass ratio of hexamethylcyclotrisilazane, glycidyl furfur ether, 2-furanmethylamine, isopropanol, tetramethylammonium hydroxide, deionized water, and composite emulsifier is (15-18):(20-25):(8-12):(15-20):(0.15-0.25):(65-75):(2.5-3.5); the composite emulsifier is prepared by mixing sucrose fatty acid ester and chitosan quaternary ammonium salt in a mass ratio of 2:(0.7-1).

[0010] Furthermore, the preparation method of the corrosion-inhibiting emulsion includes: mixing and stirring 15-18 parts by mass of hexamethylcyclotrisilazane, 20-25 parts by mass of glycidyl furfural ether, 8-12 parts by mass of 2-furanylamine, and 15-20 parts by mass of isopropanol, adding 0.15-0.25 parts by mass of tetramethylammonium hydroxide, and reacting at 70-75°C for 5-6 hours; removing isopropanol by vacuum distillation to obtain a reaction solution; mixing and stirring 65-75 parts by mass of deionized water and 2.5-3.5 parts by mass of a composite emulsifier prepared from sucrose fatty acid ester and chitosan quaternary ammonium salt in a mass ratio of 2:0.7-1, adding the reaction solution, shearing emulsification, adjusting the pH to 7.8-8.2 with dimethylethanolamine, filtering, and obtaining the corrosion-inhibiting emulsion.

[0011] The preparation of the barrier agent includes: adding lithium fluoride to hydrochloric acid and stirring, adding titanium aluminum carbide and stirring to remove it, centrifuging, washing the precipitate until neutral, dispersing it in an ethanol aqueous solution, adjusting the pH to 5.5-6.0, adding 3-aminopropyltriethoxysilane and stirring at 45-50°C, centrifuging, washing the precipitate, vacuum drying, and pulverizing through a 325-400 mesh sieve to obtain the barrier agent.

[0012] In the preparation of the barrier agent, the mass ratio of lithium fluoride, hydrochloric acid, titanium aluminum carbide, aqueous ethanol solution, and 3-aminopropyltriethoxysilane is (5-8):(60-80):(8-10):(60-80):(2-4); the concentration of hydrochloric acid is 8.5-9.0 mol / L; and the concentration of aqueous ethanol solution is 50-60 vol.

[0013] Furthermore, the preparation method of the barrier agent includes: adding 5-8 parts by mass of lithium fluoride to 60-80 parts by mass of 8.5-9.0 mol / L hydrochloric acid, stirring at 1-6°C, adding 8-10 parts by mass of titanium aluminum carbide, stirring and exfoliating at 30-35°C for 22-26 h, centrifuging, washing the precipitate with deionized water until neutral to obtain a solid, dispersing it in 60-80 parts by mass of 50-60 vol% ethanol aqueous solution, adjusting the pH to 5.5-6.0 with glacial acetic acid, adding 2-4 parts by mass of 3-aminopropyltriethoxysilane, stirring at 45-50°C for 5.5-6.5 h, centrifuging, washing the precipitate and vacuum drying, pulverizing and passing through a 325-400 mesh sieve to obtain the barrier agent.

[0014] The preparation of the slag composite filler includes: ball milling blast furnace slag powder, zeolite powder and potassium dihydrogen phosphate, sintering at 1000-1100℃ for 1-2 hours, crushing and sieving, dispersing in deionized water, adding citric acid for etching treatment to obtain etched powder; hydrolyzing boron nitride and KH-172 silane coupling agent in ethanol aqueous solution, adding the etched powder and dibutyltin dilaurate for reaction, centrifuging, washing and drying the solid, crushing and sieving to obtain the final product.

[0015] In the preparation of slag composite filler, the mass ratio of blast furnace slag powder, zeolite powder, and potassium dihydrogen phosphate is (20-30):(6-10):(1.2-1.8); the sintering is carried out at 1000-1100℃ for 1-2 hours; the amount of deionized water is 5-6 times the mass of the powder; the amount of citric acid added is 1-3% of the mass of the powder; the etching temperature is 60-65℃; and the amount of boron nitride used is equal to the amount of etching powder. The amount of KH-172 silane coupling agent is 3-5% of the mass of the etching powder; the amount of ethanol aqueous solution is 5-6 times the mass of the etching powder; the concentration of the ethanol aqueous solution is 50-60 vol%; the amount of dibutyltin dilaurate added is 0.05-0.1% of the mass of the etching powder; the reaction temperature is 70-75℃; and the mesh size of the sieve used for sieving is 650-800 mesh.

[0016] Furthermore, the preparation method of the slag composite filler includes: ball milling and mixing 20-30 parts by mass of blast furnace slag powder, 6-10 parts by mass of zeolite powder, and 1.2-1.8 parts by mass of potassium dihydrogen phosphate; sintering at 1000-1100℃ for 1-2 hours; cooling and then pulverizing through a 650-800 mesh sieve to obtain powder; dispersing the powder in 5-6 times its volume of deionized water; heating to 60-65℃; adding 1-3% by mass of citric acid to the powder; stirring and etching; centrifuging; washing the precipitate and then vacuum drying to obtain etched material. Powder: Take 5-8% boron nitride by weight of the etching powder, disperse it in 50-60 vol% ethanol aqueous solution (5-6 times the weight of the etching powder), add 3-5% KH-172 silane coupling agent by weight of the etching powder, adjust the pH to 4.5-5.0 with glacial acetic acid, stir and hydrolyze, then add the etching powder and 0.05-0.1% dibutyltin dilaurate by weight of the etching powder, stir at 70-75℃, centrifuge, wash the precipitate, vacuum dry it, pulverize it through a 650-800 mesh sieve to obtain slag composite filler.

[0017] In the above coating, the composite film-forming aid comprises dodecyl alcohol ester and diethylene glycol dimethyl ether in a mass ratio of 3:(1-1.5).

[0018] In the above coatings, the functional additives include dispersants, defoamers, and leveling agents in a mass ratio of (5-6):(2-3):(3-4).

[0019] In the above coating, the synergistic additives include sodium phytate and ammonium metavanadate in a mass ratio of 2:(1-1.5).

[0020] In the above-mentioned coating, the viscosity of the coating is adjusted with deionized water to a Forte 4 cup viscosity (25°C) of 50-70 s.

[0021] In the above-mentioned coating, the pH of the coating is adjusted to 7.8-8.2 using dimethylethanolamine.

[0022] The preparation method of the above-mentioned environmentally friendly water-based industrial anti-corrosion coating includes the following steps: Functional additives were added to deionized water under stirring, followed by stirring. Slag composite filler was then added and sheared to disperse the coating, controlling the fineness of the coating to below 15 μm. Chlorinated ether resin emulsion, corrosion inhibitor emulsion, and barrier agent were added sequentially under stirring for dispersion. Composite film-forming aid and synergistic agent were added and stirred. Terminal amino hyperbranched polyamide crosslinking agent was added and stirred. The viscosity was adjusted with deionized water until the outflow time of a Forte 4 cup viscometer was 50–70 s. The pH was adjusted to 7.8–8.2 with dimethyl ethanolamine. The coating was degassed under vacuum and filtered to obtain the final coating.

[0023] This invention provides an environmentally friendly water-based industrial anti-corrosion coating and its preparation method, with the following beneficial effects: I. This invention, an environmentally friendly water-based industrial anti-corrosion coating, achieves a high degree of unity between the environmental friendliness of the water-based system and the high performance of heavy-duty industrial anti-corrosion. Using water as the main dispersion medium significantly reduces VOC emissions. It constructs a long-lasting protection system from multiple dimensions, including active chemical corrosion prevention, physical layered barrier, dense film formation, and interfacial covalent bonding. This solves the core defects of traditional water-based anti-corrosion coatings, such as insufficient anti-corrosion performance, poor water resistance, and poor weather resistance. The coating film possesses excellent mechanical properties, acid and alkali resistance, damp heat resistance, salt spray resistance, and other anti-corrosion and weather resistance properties. It is suitable for harsh corrosion scenarios such as heavy-duty industrial anti-corrosion, shipbuilding, and marine engineering, replacing traditional solvent-based heavy-duty anti-corrosion coatings and promoting the green and high-performance development of the coating industry.

[0024] II. In the preparation of the corrosion-inhibiting emulsion, hexamethylcyclotrisilazane, glycidyl furfuryl ether, and 2-furanylamine are used as core raw materials, and sucrose fatty acid ester and chitosan quaternary ammonium salt composite emulsifiers are used as dispersing and stabilizing components. The raw material ratio achieves a dual functional integration of chemical chelation passivation and inorganic hydrophobic network. The nitrogen and oxygen active sites of the furan ring form a stable chelated passivation film with metal ions, inhibiting electrochemical corrosion; the polysilazane hydrolyzes and cross-links to generate a Si-O-Si inorganic rigid network, improving the temperature resistance and media resistance of the coating film; and it forms Si-O-Me covalent bonds with the metal substrate, significantly enhancing the interfacial adhesion between the coating film and the substrate, achieving the dual effects of active chemical corrosion protection and interfacial enhancement.

[0025] III. In the preparation of the barrier agent, lithium fluoride and titanium aluminum carbide are used as basic raw materials, 3-aminopropyltriethoxysilane as a modifier, hydrochloric acid as an etching and stripping agent, and ethanol aqueous solution as a dispersion medium. The raw material ratio achieves a functional combination of layered physical barrier and interfacial covalent bonding. The stripping parameters ensure that titanium aluminum carbide is fully stripped into layered nanosheets. Subsequently, the silane coupling agent is fully aminated to improve dispersibility. The layered nanosheet structure significantly extends the penetration path of corrosive media such as water, oxygen, and chloride ions, forming a highly efficient physical barrier. The active amino groups introduced by the amination modification form covalent bonds with the resin and crosslinking agent, eliminating interfacial voids between inorganic fillers and organic resins, and preventing corrosive media from penetrating along the interface. The acid and alkali resistance and weather resistance of the ceramic substrate further enhance the protective effect of the coating, achieving the dual effects of physical barrier and interface defect elimination.

[0026] IV. In the preparation of slag composite filler, blast furnace slag powder and zeolite powder are used as the matrix, potassium dihydrogen phosphate is used as the mineralizing agent, citric acid is used as the etching agent, boron nitride is used as the shielding layer, KH-172 silane coupling agent is used as the coupling agent, and dibutyltin dilaurate is used as the condensation catalyst. The raw material ratio realizes the triple function integration of microcrystalline chemical inertness, core-shell physical shielding and chemical passivation.

[0027] Sintering parameters ensure the formation of a stable microcrystalline glass phase between blast furnace slag and zeolite powder; etching treatment constructs multi-level micropores on the filler surface, enhancing mechanical bonding with the resin; KH-172 silane coupling agent grafts boron nitride onto the filler surface, forming a core-shell structure. The microcrystalline glass phase possesses extremely high chemical inertness and structural density, improving the filler's corrosion resistance; multi-level micropores enhance the mechanical bonding with the resin; the two-dimensional layered characteristics of boron nitride in the core-shell structure strengthen the physical shielding effect; the phosphate component formed by potassium dihydrogen phosphate sintering achieves chemical passivation of the metal substrate, realizing a triple effect of microcrystalline stabilization, core-shell shielding, and chemical passivation.

[0028] 5. Dodecyl alcohol ester and diethylene glycol dimethyl ether are compounded in a certain proportion to complement each other's film-forming defects. Dodecyl alcohol ester ensures that the emulsion particles are fully fused, while diethylene glycol dimethyl ether controls the film-forming rate. Together, they promote the formation of a continuous, dense coating without microscopic defects from the polymer emulsion particles, laying the structural foundation for all protective properties such as corrosion inhibition, barrier, and crosslinking.

[0029] VI. In the preparation of coating components, the functional additives are first dispersed in deionized water, and then slag composite filler is added for high-speed shear dispersion. The fineness of the coating is controlled to be below 15μm to ensure that the filler is uniformly dispersed in the system, avoid agglomeration, reduce micropores and defects inside the coating film, and improve the density of the coating film. Chlorinated ether resin emulsion, corrosion inhibitor emulsion, and barrier agent are added sequentially for medium-high speed dispersion to ensure that each functional phase is uniformly distributed in the resin matrix, so that the corrosion inhibition and barrier functions can be fully exerted in the coating film and avoid local weak protection. After slowing down, composite film-forming aids and synergistic aids are added, and then terminal amino hyperbranched polyamide crosslinking agent is added to avoid the crosslinking agent reacting prematurely and the film-forming aid volatilizing due to high speed. This ensures that the film-forming aid promotes the fusion of emulsion particles and that the crosslinking agent is fully covalently bonded to the active sites of each component.

[0030] VII. The organic chelation passivation of the corrosion-inhibiting emulsion and the anodic-cathode inorganic corrosion inhibition of the synergistic additives (sodium phytate, ammonium metavanadate) form a full-interface passivation system. The organic corrosion-inhibiting components cover the surface of the metal substrate, while the inorganic corrosion-inhibiting components fill the protective gaps at microscopic defects, achieving comprehensive inhibition of electrochemical corrosion. The layered nanosheet physical barrier of the barrier agent and the core-shell structure physical shielding of the slag composite filler form a multi-level penetration path extension system. The corrosive medium must pass through the core-shell shielding of boron nitride and the layered barrier of titanium aluminum carbide in sequence, significantly extending the penetration path and greatly reducing the probability of the corrosive medium reaching the metal substrate. The chloroether resin emulsion serves as the film-forming matrix. The terminal amino hyperbranched polyamide crosslinking agent covalently bonds with the epoxy groups of the chloroether resin and corrosion-inhibiting emulsion, as well as the amino and hydroxyl groups on the surface of the barrier agent and filler, forming a high crosslinking density network. This not only improves the hardness, flexibility, and impact resistance of the coating film, but also reduces the free volume of the system, reduces hydrophilic channels, and simultaneously improves water resistance, damp heat resistance, and weather resistance. Through multi-dimensional synergistic effects, the components achieve simultaneous improvements in environmental friendliness, mechanical properties, corrosion resistance, and weather resistance, enabling water-based coatings to achieve performance levels comparable to traditional solvent-based heavy-duty anti-corrosion coatings. Detailed Implementation

[0031] Some embodiments are given below, but the present invention is not limited to these embodiments.

[0032] Example 1 An environmentally friendly water-based industrial anti-corrosion coating comprises the following raw materials in parts by weight: 43 parts of chloroethyl ether resin emulsion, 12 parts of corrosion inhibitor emulsion, 6.5 parts of barrier agent, 14 parts of slag composite filler, 6 parts of amino-terminated hyperbranched polyamide crosslinking agent, 2.8 parts of composite film-forming aid, 1.8 parts of functional aid, 1 part of synergistic aid, and the balance being deionized water. The composite film-forming aid includes dodecyl alcohol ester and diethylene glycol dimethyl ether in a mass ratio of 3:1.3. The functional aid includes dispersant, defoamer, and leveling agent in a mass ratio of 5.5:2.5:3.5. The synergistic aid includes sodium phytate and ammonium metavanadate in a mass ratio of 2:1.2.

[0033] The preparation method of the corrosion-inhibiting emulsion includes: mixing 17 parts by mass of hexamethylcyclotrisilazane, 23 parts by glycidyl furfural ether, 10 parts by 2-furanylamine, and 18 parts by mass under nitrogen protection, stirring at 450 r / min, adding 0.2 parts by mass of tetramethylammonium hydroxide, and reacting at 70-75℃ and 450 r / min for 5.5 h until the epoxy value drops below 0.01 mol / 100 g; after the reaction is completed, isopropanol is removed by vacuum distillation at 70-75℃ to obtain the reaction solution. Under nitrogen protection, 70 parts of deionized water and 3 parts of composite emulsifier (sucrose fatty acid ester and chitosan quaternary ammonium salt in a mass ratio of 2:0.85) were mixed and stirred at 620 r / min for 12 min. The reaction solution was then added. The system temperature was controlled to not exceed 30℃, and the mixture was sheared at 3200 r / min for 25 min. The pH was adjusted to 8.0 with dimethylethanolamine while stirring at 320 r / min. The mixture was then filtered through a 150-mesh filter cloth to obtain a corrosion-inhibiting emulsion, specifically a bio-based furan-modified polysilazane corrosion-inhibiting emulsion.

[0034] The preparation method of the barrier agent includes: by mass, under nitrogen protection, adding 6.5 parts of lithium fluoride to 70 parts of 8.8 mol / L hydrochloric acid, stirring at 280 r / min for 30 min in a temperature range of 1-6℃, adding 9 parts of titanium aluminum carbide (Ti3AlC2 passed through a 325-mesh sieve), stirring at 280 r / min for 24 h in a temperature range of 30-35℃, centrifuging at 5000 r / min for 25 min, washing the precipitate with deionized water until neutral, and obtaining a solid. The solid was dispersed in 70 parts of 55 vol% ethanol aqueous solution, the pH was adjusted to 5.8 with glacial acetic acid, 3 parts of 3-aminopropyltriethoxysilane were added, and the mixture was stirred at 320 r / min for 6 h at a temperature range of 45-50 °C. After centrifugation at 5000 r / min for 25 min, the precipitate was washed twice with anhydrous ethanol and then twice with deionized water. The precipitate was dried under vacuum at 55 °C for 18 h and then pulverized through a 325 mesh sieve to obtain the barrier agent, specifically an aminated MAX phase ceramic barrier agent.

[0035] The preparation method of the slag composite filler includes: 25 parts by mass of blast furnace slag powder, 8 parts by mass of zeolite powder, and 1.5 parts by mass of potassium dihydrogen phosphate are ball-milled (ball-to-material ratio 5.5:1, rotation speed 25 r / min) for 1.5 h; sintered at 1050℃ for 1.5 h; cooled and then pulverized through a 650-mesh sieve to obtain powder. The powder is dispersed in 5.5 times its weight of deionized water, heated to 62℃, and 2% by mass of citric acid is added. The mixture is stirred and etched for 2 h, centrifuged at 6500 r / min for 20 min, the precipitate is washed with deionized water until neutral, and then vacuum dried at 80℃ for 4 h to obtain etched powder. Boron nitride of 6.5% by weight of the etching powder was dispersed in a 55 vol% ethanol aqueous solution of 5.5 times the weight of the etching powder. KH-172 silane coupling agent of 4% by weight of the etching powder was added. The pH was adjusted to 4.8 with glacial acetic acid. The mixture was stirred at 250 r / min for 25 min for hydrolysis. Then the etching powder was added, followed by dibutyltin dilaurate of 0.08% by weight of the etching powder. The mixture was stirred at 70-75℃ for 2 h under nitrogen protection, centrifuged at 6500 r / min for 20 min, and the precipitate was washed once with anhydrous ethanol and twice with deionized water. The precipitate was vacuum dried at 85℃ for 6 h and then pulverized through a 650 mesh sieve to obtain the slag composite filler, specifically a slag-based microcrystalline glass passivation composite filler.

[0036] The preparation method of the above-mentioned environmentally friendly water-based industrial anti-corrosion coating includes the following steps: Functional additives were added to deionized water under stirring at 450 r / min for 9 min; slag composite filler was added and sheared at 2200 r / min for 35 min to control the coating fineness to below 15 μm; under stirring at 750 r / min, chloroether resin emulsion, corrosion inhibitor emulsion, and barrier agent were added sequentially, the speed was increased to 1300 r / min and dispersed for 8 min, the speed was reduced to 700 r / min, composite film-forming aid and synergistic aid were added, and stirring was continued for 12 min; terminal amino hyperbranched polyamide crosslinking agent was added and stirring was continued for 12 min; the viscosity was adjusted with deionized water to a flow time of 60 s on a Forte 4 cup viscometer (25℃), the pH was adjusted to 8.0 with dimethyl ethanolamine, and the coating was degassed under vacuum at -0.075 MPa for 12 min and filtered through a 120 mesh to obtain the coating.

[0037] Example 2 An environmentally friendly water-based industrial anti-corrosion coating comprises the following raw materials in parts by weight: 40 parts of chloroethyl ether resin emulsion, 14 parts of corrosion inhibitor emulsion, 5 parts of barrier agent, 16 parts of slag composite filler, 5 parts of amino-terminated hyperbranched polyamide crosslinking agent, 3.5 parts of composite film-forming aid, 1.5 parts of functional aid, 1.3 parts of synergistic aid, and the balance being deionized water. The composite film-forming aid includes dodecyl alcohol ester and diethylene glycol dimethyl ether in a 3:1 mass ratio. The functional aid includes dispersant, defoamer, and leveling agent in a 6:2:4 mass ratio. The synergistic aid includes sodium phytate and ammonium metavanadate in a 2:1 mass ratio.

[0038] The preparation method of the corrosion-inhibiting emulsion includes: mixing 15 parts by mass of hexamethylcyclotrisilazane, 20 parts by glycidyl furfural ether, 8 parts by 2-furanylamine, and 15 parts by mass under nitrogen protection, stirring at 400 r / min, adding 0.15 parts by mass of tetramethylammonium hydroxide, and reacting at 70-75℃ and 400 r / min for 5 h until the epoxy value drops below 0.01 mol / 100 g; after the reaction is completed, removing the isopropanol by vacuum distillation at 70-75℃ to obtain the reaction solution. Under nitrogen protection, 65 parts of deionized water and 2.5 parts of composite emulsifier (sucrose fatty acid ester and chitosan quaternary ammonium salt in a mass ratio of 2:0.7) were mixed and stirred at 600 r / min for 10 min. The reaction solution was then added. The system temperature was controlled to not exceed 30℃, and shear emulsification was performed at 3000 r / min for 20 min. The pH was adjusted to 7.8 with dimethylethanolamine while stirring at 300 r / min. The mixture was then filtered through a 150-mesh filter cloth to obtain a corrosion-inhibiting emulsion, specifically a bio-based furan-modified polysilazane corrosion-inhibiting emulsion.

[0039] The preparation method of the barrier agent includes: by mass, under nitrogen protection, adding 8 parts of lithium fluoride to 80 parts of 9.0 mol / L hydrochloric acid, stirring at 300 r / min for 35 min in a temperature range of 1-6℃, adding 10 parts of titanium aluminum carbide (Ti3AlC2 passed through a 400-mesh sieve), stirring at 300 r / min for 26 h in a temperature range of 30-35℃, centrifuging at 6000 r / min for 15 min, washing the precipitate with deionized water until neutral, and obtaining a solid. The solid was dispersed in 80 parts of 60 vol% ethanol aqueous solution, the pH was adjusted to 6.0 with glacial acetic acid, 4 parts of 3-aminopropyltriethoxysilane were added, and the mixture was stirred at 350 r / min for 6.5 h at a temperature range of 45-50 °C, centrifuged at 6000 r / min for 15 min, the precipitate was washed 3 times with anhydrous ethanol and then washed once with deionized water, dried under vacuum at 60 °C for 12 h, and pulverized through a 400 mesh sieve to obtain the barrier agent, specifically an aminated MAX phase ceramic barrier agent.

[0040] The preparation method of the slag composite filler includes: 20 parts by mass of blast furnace slag powder, 6 parts by mass of zeolite powder, and 1.2 parts by mass of potassium dihydrogen phosphate are ball-milled (ball-to-material ratio 5:1, rotation speed 20 r / min) for 1.5 h; sintered at 1000℃ for 2 h; cooled and then pulverized through a 650-mesh sieve to obtain powder. The powder is dispersed in deionized water at 5 times its weight, heated to 60℃, and 1% by mass of citric acid is added. The mixture is stirred and etched for 1.5 h, centrifuged at 6000 r / min for 30 min, the precipitate is washed with deionized water until neutral, and then vacuum dried at 75℃ for 5 h to obtain etched powder. Take 5% boron nitride by weight of the etching powder and disperse it in 50 vol% ethanol aqueous solution, which is 5 times the weight of the etching powder. Add 3% KH-172 silane coupling agent by weight of the etching powder. Adjust the pH to 4.5 with glacial acetic acid and stir at 200 r / min for 20 min for hydrolysis. Then add the etching powder and 0.05% dibutyltin dilaurate by weight of the etching powder. Stir at 70-75℃ for 1.5 h under nitrogen protection and centrifuge at 6000 r / min for 30 min. Wash the precipitate once with anhydrous ethanol and once with deionized water. Dry it under vacuum at 80℃ for 7 h and pulverize it through a 650 mesh sieve to obtain slag composite filler, specifically slag-based microcrystalline glass passivation composite filler.

[0041] The preparation method of the above-mentioned environmentally friendly water-based industrial anti-corrosion coating includes the following steps: Functional additives were added to deionized water under stirring at 400 rpm for 10 min; slag composite filler was added and sheared at 2000 rpm for 40 min to control the coating fineness to below 15 μm; under stirring at 700 rpm, chloroether resin emulsion, corrosion inhibitor emulsion, and barrier agent were added sequentially, the speed was increased to 1500 rpm for 5 min, the speed was reduced to 800 rpm, composite film-forming aid and synergistic agent were added, and stirring was continued for 10 min; terminal amino hyperbranched polyamide crosslinking agent was added, and stirring was continued for 15 min; the viscosity was adjusted with deionized water to a flow time of 50 s on a Forte 4 cup viscometer (25℃); the pH was adjusted to 7.8 with dimethyl ethanolamine; the coating was degassed under vacuum at -0.07 MPa for 15 min and filtered through a 120 mesh to obtain the coating.

[0042] Example 3 An environmentally friendly water-based industrial anti-corrosion coating comprises the following raw materials in parts by weight: 45 parts of chloroethyl ether resin emulsion, 10 parts of corrosion inhibitor emulsion, 8 parts of barrier agent, 12 parts of slag composite filler, 7 parts of amino-terminated hyperbranched polyamide crosslinking agent, 2.0 parts of composite film-forming aid, 2.0 parts of functional aid, 0.8 parts of synergistic aid, and the balance being deionized water. The composite film-forming aid includes dodecyl alcohol ester and diethylene glycol dimethyl ether in a mass ratio of 3:1.5. The functional aid includes dispersant, defoamer, and leveling agent in a mass ratio of 5:3:3. The synergistic aid includes sodium phytate and ammonium metavanadate in a mass ratio of 2:1.5.

[0043] The preparation method of the corrosion-inhibiting emulsion includes: mixing 18 parts by mass of hexamethylcyclotrisilazane, 25 parts by glycidyl furfural ether, 12 parts by mass of 2-furanmethylamine, and 20 parts by mass of isopropanol under nitrogen protection, stirring at 500 r / min, adding 0.25 parts by mass of tetramethylammonium hydroxide, and reacting at 70-75℃ and 500 r / min for 6 h until the epoxy value drops below 0.01 mol / 100 g; after the reaction is completed, isopropanol is removed by vacuum distillation at 70-75℃ to obtain the reaction solution. Under nitrogen protection, 75 parts of deionized water and 3.5 parts of composite emulsifier (sucrose fatty acid ester and chitosan quaternary ammonium salt in a mass ratio of 2:1) were mixed and stirred at 650 r / min for 15 min. The reaction solution was then added. The system temperature was controlled to not exceed 30℃, and the mixture was sheared at 3500 r / min for 30 min. The pH was adjusted to 8.2 with dimethyl ethanolamine while stirring at 350 r / min. The mixture was then filtered through a 200-mesh filter cloth to obtain a corrosion-inhibiting emulsion, specifically a bio-based furan-modified polysilazane corrosion-inhibiting emulsion.

[0044] The preparation method of the barrier agent includes: by mass, under nitrogen protection, adding 5 parts of lithium fluoride to 60 parts of 8.5 mol / L hydrochloric acid, stirring at 250 r / min for 25 min in a temperature range of 1-6℃, adding 8 parts of titanium aluminum carbide (Ti3AlC2 passed through a 325 mesh sieve), stirring at 250 r / min for 22 h in a temperature range of 30-35℃, centrifuging at 4000 r / min for 30 min, washing the precipitate with deionized water until neutral, and obtaining a solid. The solid was dispersed in 60 parts of 50 vol% ethanol aqueous solution, the pH was adjusted to 5.5 with glacial acetic acid, 2 parts of 3-aminopropyltriethoxysilane were added, and the mixture was stirred at 300 r / min for 5.5 h at a temperature range of 45-50 °C, centrifuged at 4000 r / min for 30 min, the precipitate was washed twice with anhydrous ethanol, then washed twice with deionized water, dried under vacuum at 50 °C for 24 h, and pulverized through a 325 mesh sieve to obtain the barrier agent, specifically an aminated MAX phase ceramic barrier agent.

[0045] The preparation method of the slag composite filler includes: 30 parts by mass of blast furnace slag powder, 10 parts by mass of zeolite powder, and 1.8 parts by mass of potassium dihydrogen phosphate are ball-milled (ball-to-material ratio 6:1, rotation speed 30 r / min) for 2 h; sintered at 1100℃ for 1 h; cooled and pulverized through an 800-mesh sieve to obtain powder. The powder is dispersed in deionized water at 6 times its weight, heated to 65℃, and citric acid at 3% of the powder weight is added. The mixture is stirred and etched for 2.5 h, centrifuged at 7000 r / min for 15 min, the precipitate is washed with deionized water until neutral, and vacuum dried at 85℃ for 3 h to obtain etched powder. Boron nitride at 8% of the etching powder mass was dispersed in a 60 vol% ethanol aqueous solution at 6 times the mass of the etching powder mass. KH-172 silane coupling agent at 5% of the etching powder mass was added, and the pH was adjusted to 5.0 with glacial acetic acid. The mixture was stirred at 300 r / min for 30 min for hydrolysis. Then, the etching powder mass was added, followed by dibutyltin dilaurate at 0.1% of the etching powder mass. The mixture was stirred at 70–75 °C for 2.5 h under nitrogen protection, centrifuged at 7000 r / min for 15 min, and the precipitate was washed twice with anhydrous ethanol and then twice with deionized water. The precipitate was vacuum dried at 90 °C for 5 h and then pulverized through an 800 mesh sieve to obtain the slag composite filler, specifically a slag-based microcrystalline glass passivation composite filler.

[0046] The preparation method of the above-mentioned environmentally friendly water-based industrial anti-corrosion coating includes the following steps: Functional additives were added to deionized water under stirring at 500 rpm for 8 min; slag composite filler was added and sheared at 2500 rpm for 30 min to control the coating fineness to below 15 μm; under stirring at 800 rpm, chloroether resin emulsion, corrosion inhibitor emulsion, and barrier agent were added sequentially, the speed was increased to 1200 rpm for 10 min, the speed was reduced to 600 rpm, composite film-forming aid and synergistic agent were added, and stirring was continued for 15 min; terminal amino hyperbranched polyamide crosslinking agent was added, and stirring was continued for 10 min; the viscosity was adjusted with deionized water to a flow time of 70 s on a Forte 4 cup viscometer (25℃); the pH was adjusted to 8.2 with dimethyl ethanolamine; the coating was degassed under vacuum at -0.08 MPa for 10 min and filtered through a 150 mesh to obtain the coating.

[0047] The raw material specifications and sources involved in the above embodiments are as follows: The chloroether resin emulsion is an aqueous chloroether resin emulsion sourced from Jiangyin Huitong Fine Chemical Co., Ltd., with a solid content of 40 wt% and a viscosity of 10 mPa·s. The terminal amino hyperbranched polyamide crosslinking agent is sourced from Qingdao Haisu New Material Technology Co., Ltd., model HD03, with a molecular weight of 1900-2200 and an amino number / mol of 12-16. The dispersant is Anjeka-6871 dispersant sourced from Ezhou Anjikang Technology Co., Ltd. The defoamer is TEGO Foamex 812 sourced from Evonik Specialty Chemicals (Shanghai) Co., Ltd. The leveling agent is a fluorinated modified acrylate leveling agent sourced from Ezhou Anjikang Technology Co., Ltd., model Anjeka 7377. The sucrose fatty acid ester is sourced from Zhengzhou Longsheng Chemical Products Co., Ltd. The chitosan quaternary ammonium salt is sourced from Shandong Yatu Biotechnology Co., Ltd. The blast furnace slag powder is S105 grade slag powder with a particle size passing through a 650-800 mesh sieve, sourced from Lingshou County Fuda Mineral Products Processing Plant. The zeolite powder, with a particle size passing through a 325-400 mesh sieve, was sourced from Shifeng Mining Processing Plant in Lingshou County; it was white zeolite powder. The titanium aluminum carbide (Ti3AlC2), with a particle size passing through a 325-400 mesh sieve, was sourced from Zhejiang Yamei Nanotechnology Co., Ltd. The boron nitride, with a particle size passing through a 650-800 mesh sieve, was sourced from Zhejiang Yamei Nanotechnology Co., Ltd.; it was hexagonal boron nitride. The KH-172 silane coupling agent was sourced from Hubei Chushengwei Chemical Co., Ltd. The tetramethylammonium hydroxide was a 25wt% tetramethylammonium hydroxide aqueous solution, sourced from Hubei Xinjiecheng Chemical Technology Co., Ltd. The purity of all other unlisted raw materials was above 99%.

[0048] Comparative Example 1 The difference from Example 1 is that the corrosion-inhibiting emulsion is changed to 5 parts.

[0049] Comparative Example 2 The difference from Example 1 is that the barrier agent is changed to 1.5 parts and the slag composite filler is changed to 19 parts.

[0050] Comparative Example 3 The difference from Example 1 is that no composite film-forming aid is added.

[0051] Comparative Example 4 The difference from Example 1 is that all composite film-forming aids are made of dodecyl alcohol esters.

[0052] Comparative Example 5 The difference from Example 1 is that all composite film-forming aids are diethylene glycol dimethyl ether.

[0053] Comparative Example 6 The difference from Example 1 is that 2-furan methylamine is not added in the preparation of the corrosion-inhibiting emulsion.

[0054] Comparative Example 7 The difference from Example 1 is that hexamethylcyclotrisilazane is not added in the preparation of the corrosion-inhibiting emulsion.

[0055] Comparative Example 8 The difference from Example 1 is that potassium dihydrogen phosphate is not added in the preparation of the slag composite filler; and the sintering temperature is changed to 800℃.

[0056] Comparative Example 9 The difference from Example 1 is that the slag composite filler is directly replaced by etched powder.

[0057] Comparative Example 10 The difference from Example 1 is that boron nitride and dibutyltin dilaurate are not added in the preparation of the slag composite filler.

[0058] Recommended curing methods for the above coatings: For conventional corrosion protection, room temperature curing is required: single coat 40μm~80μm, 23±2℃, relative humidity 50±5%, curing time 10~14 days.

[0059] Conventional corrosion protection uses low-temperature baking curing: single pass 40μm~80μm, bake at 60~80℃ for 60~90min for curing.

[0060] High-temperature curing for heavy-duty corrosion protection: single-pass 40μm~120μm, pre-baking at 55~60℃ for 30~40min, melting film at 90~100℃ for 25~35min, cross-linking and curing at 140~150℃ for 40~50min, and constant temperature curing at 100~120℃ for 20~30min.

[0061] The following curing conditions were uniformly adopted for the following tests: pre-baking at 55℃ for 30 min, melting at 90℃ for 30 min, cross-linking and curing at 140℃ for 40 min, and constant temperature curing at 120℃ for 20 min.

[0062] I. VOC content detection: Reference standard: GB / T 23986.2-2023 "Determination of volatile organic compounds (VOCs) and / or semi-volatile organic compounds (SVOCs) in paints and varnishes - Part 2: Gas chromatography".

[0063] Sample specifications: liquid coating, 3 parallel samples per group.

[0064] Detection parameters: Weigh 1.0 g of sample into a headspace vial, add 5 mL of chromatographically pure methanol, seal and ultrasonically extract for 30 min; detect using gas chromatography, with a DB-WAX capillary column (30 m × 0.25 mm × 0.25 μm), injection port temperature 200℃, detector temperature 250℃; column temperature program: 40℃ for 2 min, increase to 180℃ at 10℃ / min and hold for 5 min; calculate content using external standard method. Detection results: The VOC content of the coatings in all examples and comparative examples was below 25 g / L.

[0065] II. Pencil Hardness Test of Paint Film: Reference standard: GB / T 6739-2022 "Determination of Hardness of Paints and Varnishes by Pencil Method".

[0066] Sample specifications: Tinplate conforming to GB / T 9271-2008 standard, dry film thickness 40±2μm, 3 parallel samples per group.

[0067] Test parameters: A pencil hardness tester was used, with 2B-6H pencils sharpened into a cylindrical shape. The pencil was run across the paint film at a 45° angle and 1kg pressure at a constant speed, starting with the hardest pencil. The hardness of the paint film was determined by the highest pencil hardness that left no scratch.

[0068] III. Coating adhesion test: Reference standard: GB / T 9286-2021 "Cross-cut test for paints and varnishes".

[0069] Sample specifications: Tinplate conforming to GB / T 9271-2008 standard, dry film thickness 40±2μm, 3 parallel samples per group.

[0070] Testing parameters: The cross-cut test is performed, using a cross-cutting tool to draw 25 1mm x 1mm squares on the paint film. Remove loose debris with a brush, apply 3M 600 tape, and quickly peel it off. Rate the peeling level from 0 to 5.

[0071] IV. Coating film flexibility test: Reference standard: GB / T 1731-2020 "Determination of flexibility of paint film and putty film".

[0072] Sample specifications: Tinplate conforming to GB / T 9271-2008 standard (thickness 0.2mm), dry film thickness 40±2μm, 3 parallel samples per group.

[0073] Test parameters: Bend the painted tinplate on a 1mm diameter shaft and observe whether there are cracks in the paint film. Record the smallest shaft diameter without cracks.

[0074] V. Impact resistance test of paint film: Reference standard: GB / T 1732-2020 "Test method for impact resistance of paint film".

[0075] Sample specifications: Tinplate conforming to GB / T 9271-2008 standard, dry film thickness 40±2μm, 3 parallel samples per group.

[0076] Test parameters: Using an impact tester, a 1kg hammer is dropped freely from a height of 40cm, increasing by 5cm each time, to impact the paint film surface. The paint film is observed for cracks, wrinkles, or peeling. If there are no abnormalities, it is considered a pass; otherwise, it is considered a fail. The maximum impact height that passes is recorded.

[0077] VI. Neutral Salt Spray Resistance Test: Reference standard: GB / T 10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test".

[0078] Sample specifications: 150mm×75mm×1.0mm Q235 cold-rolled steel sheet, sandblasted to Sa2.5 grade according to GB / T 8923.1-2011 standard, with a surface roughness of 50μm, a dry film thickness of 80±2μm, and the paint film cross lines reaching the substrate with a scratch angle of 45°. The edges are sealed with paraffin wax, and 3 parallel samples are used in each group.

[0079] Test parameters: Salt spray chamber temperature 35±1℃, saturation tower temperature 47±1℃, continuous spraying of 5.0wt% NaCl solution (pH 6.8), test duration 1000h. After the test, rinse with clean water, dry, and observe for blistering, rusting, peeling, and corrosion at the scratched areas. Rust at the scratched areas <1mm, with no blistering or rust on the plate surface, is considered a pass; otherwise, it is a fail.

[0080] VII. Acid and alkali resistance test: Reference standard: GB / T 9274-1988 "Determination of resistance to liquid media for paints and varnishes".

[0081] Sample specifications: 150mm×75mm×1.0mm Q235 cold-rolled steel sheet, sandblasted to Sa2.5 grade according to GB / T 8923.1-2011 standard, surface roughness 50μm, dry film thickness 45±2μm, edge sealed, 3 parallel samples per group.

[0082] Test parameters: Acid resistance: 2 / 3 of the test panel area was immersed in a 5wt% H2SO4 solution at 23±2℃ for 30 consecutive days; Alkali resistance: 2 / 3 of the test panel area was immersed in a 5wt% NaOH solution at 23±2℃ for 30 consecutive days. After immersion, the panels were rinsed with clean water and dried, and the paint film condition was observed.

[0083] 8. Damp heat resistance test: Reference standard: GB / T 1740-2007 "Determination of resistance to damp heat of paint film".

[0084] Sample specifications: 150mm×75mm×1.0mm Q235 cold-rolled steel sheet, sandblasted to Sa2.5 grade according to GB / T 8923.1-2011 standard, with a surface roughness of 50μm, a dry film thickness of 80±2μm, and edge sealing, with 3 parallel samples per group.

[0085] Test parameters: Humidity chamber temperature 47±1℃, relative humidity 96±2%, continuous test for 480 hours. After the test, remove and dry for 24 hours to observe the paint film condition.

[0086] IX. Water resistance test: Reference standard: GB / T 1733-1993 "Determination of water resistance of paint film".

[0087] Sample specifications: 150mm×75mm×1.0mm Q235 cold-rolled steel sheet, sandblasted to Sa2.5 grade according to GB / T 8923.1-2011 standard, surface roughness 50μm, dry film thickness 45±2μm, edge sealed, 3 parallel samples per group.

[0088] Test parameters: Immerse 2 / 3 of the test panel in deionized water at 23±2℃ for 60 consecutive days. After the test, remove the panel and dry it for 24 hours to observe the condition of the paint film.

[0089] 10. Artificial accelerated weathering test: Reference standard: GB / T 1865-2009 Paints and varnishes - Artificial weathering and artificial radiation exposure - Filtered xenon arc radiation.

[0090] Sample specifications: 150mm×75mm×1.0mm Q235 cold-rolled steel sheet, sandblasted to Sa2.5 grade according to GB / T 8923.1-2011 standard, with a surface roughness of 50μm and a dry film thickness of 80±2μm. Three parallel samples were used in each group.

[0091] Test parameters: Xenon arc lamp weathering test chamber, irradiance 0.51W / m² 2 (340nm), blackboard temperature 65±2℃, relative humidity 50±10%. Cyclic conditions: 102min light exposure + 18min spraying, total test duration 2000h. After the test, the coating film was removed and observed.

[0092] The paint film condition ratings for test items seven to ten are conducted in accordance with GB / T 1766-2008: individual ratings for gloss loss, discoloration, chalking, blistering, cracking, and peeling are each from 0 to 5. Finally, a comprehensive rating is given based on the overall aging of the paint film.

[0093] The results of tests two through ten are shown in Table 1 below.

[0094] Table 1. Test Results (Average Values) The coating test results from Examples 1 to 3 above show that the coating uses water as a dispersant, achieving a balance between low VOC environmental friendliness and high-performance heavy-duty corrosion protection. The corrosion-inhibiting emulsion has corrosion-inhibiting and interface-enhancing effects: the nitrogen and oxygen active sites of the furan ring can form a stable chelated passivation film with metal ions, inhibiting the electrochemical corrosion reactions of anodic dissolution and cathodic hydrogen evolution; the polysilazane hydrolysis crosslinks to generate a Si-O-Si inorganic rigid network, improving the coating's temperature and media resistance, while simultaneously forming Si-O-Me covalent bonds with the metal substrate, significantly enhancing the interfacial adhesion between the coating and the substrate, thus achieving active corrosion protection from a chemical perspective. The barrier agent achieves layered physical barrier and eliminates interface defects: Ti3AlC2 is etched by acid to form a layered nanosheet structure, which greatly extends the penetration path of corrosive media such as water, oxygen, and chloride ions, forming a highly efficient physical barrier; the amination modification of 3-aminopropyltriethoxysilane introduces active amino groups on the surface of the barrier agent, which can form covalent bonds with resin and crosslinking agent, eliminate the interfacial gaps between inorganic fillers and organic resin, and prevent corrosive media from penetrating along the interface. At the same time, the acid and alkali resistance and weather resistance of the ceramic itself further enhance the protective effect. Slag composite fillers possess microcrystalline stabilization, core-shell shielding, and chemical passivation properties: blast furnace slag and zeolite powder, after high-temperature sintering and potassium dihydrogen phosphate mineralization, form a microcrystalline glass phase with extremely high chemical inertness and structural density. Citric acid etching constructs multi-level micropores on the filler surface, enhancing mechanical interlocking with the resin. KH-172 silane coupling agent grafts boron nitride onto the filler surface, forming a core-shell structure. The two-dimensional layered characteristics of boron nitride further strengthen the physical shielding effect, and the phosphate components formed during sintering by potassium dihydrogen phosphate can also chemically passivate the metal substrate. Amino-terminated hyperbranched polyamide crosslinking agents can covalently bond at multiple points with the epoxy groups of chloroether resin emulsions and corrosion inhibitor emulsions, as well as the amino and hydroxyl groups on the surface of barrier agents and fillers, forming a high-crosslink density network. This not only restricts polymer chain movement, improving the hardness, flexibility, and impact resistance of the coating, but also reduces the free volume of the system, decreases hydrophilic channels, and improves the water resistance, damp heat resistance, and weather resistance of the coating. The combination of dodecyl alcohol ester and diethylene glycol dimethyl ether can efficiently promote the fusion and aggregation of polymer emulsion particles, forming a continuous, dense coating free of microscopic defects, laying the foundation for all protective properties. The synergistic additives composed of sodium phytate and ammonium metavanadate form an anodic-cathode synergistic corrosion inhibition system, complementing the organic corrosion inhibitors to achieve full-interface passivation protection of the metal surface.

[0095] In Comparative Example 1, the amount of corrosion-inhibiting emulsion was reduced. The corrosion-inhibiting emulsion is the core component of chemical active corrosion inhibition and Si-O-Si hydrophobic network. Insufficient dosage resulted in the inability to form a complete chelated passivation film on the metal surface, making electrochemical corrosion easier to trigger. The number of cross-linking points in the Si-O-Si network in the coating film decreased, the structure became loose, and the permeability of the corrosive medium increased. At the same time, the covalent bonding sites with the resin and filler were missing, and the interfacial compatibility decreased. Ultimately, this resulted in the simultaneous decline of anti-corrosion performance and interfacial performance.

[0096] In Comparative Example 2, the amount of barrier agent was reduced while the amount of slag composite filler was excessive. The barrier agent is the core of the layered physical barrier. The reduction directly led to a significant shortening of the penetration path of the corrosive medium and a significant decrease in the physical barrier effect. The excessive amount of slag was insufficient to compensate for the defects caused by the reduction of the barrier agent. Furthermore, the excessive amount of composite filler led to an increase in defects such as micropores and interfacial voids inside the coating, resulting in a decrease in film density. Corrosive media could easily penetrate along the defects. At the same time, the agglomeration of filler caused stress concentration and a decrease in performance.

[0097] In Comparative Example 3, no composite film-forming aid was added. Composite film-forming aid is the key to the dense film formation of water-based emulsions. Without film-forming aid, the water evaporates too quickly, causing the emulsion particles to solidify before they are fully fused. This results in the formation of a large number of micropores, gaps, and interface defects in the coating, which constitute continuous hydrophilic channels. Incomplete film formation directly leads to a decrease in mechanical properties, and corrosive media can easily pass through the defects to reach the metal substrate, causing various corrosion resistance properties to deteriorate.

[0098] In Comparative Example 4, the composite film-forming aid used only dodecyl alcohol ester. Dodecyl alcohol ester has a high boiling point and a slow evaporation rate. When used alone, it is easy to remain in the coating film under baking and curing conditions, acting as a plasticizer, reducing the glass transition temperature of the coating film, and causing a decrease in hardness. At the same time, the residual aid forms hydrophilic micro-regions, prolonging the open time of the coating film, affecting the initial water resistance and anti-corrosion performance. Moreover, the slow film-forming rate can easily lead to an increase in internal stress in the coating film and insufficient local density.

[0099] In Comparative Example 5, the composite film-forming aid used only was diethylene glycol dimethyl ether. Diethylene glycol dimethyl ether has a low boiling point and evaporates too quickly, resulting in insufficient fusion time for emulsion particles, forming a porous and loose coating film with numerous microscopic defects. Its strong polarity also causes excessive swelling of polymer emulsion particles, damaging emulsion stability, leading to local demulsification and uneven coating film, weak interfacial adhesion, and ultimately, lower anti-corrosion performance and mechanical properties compared to the compound system.

[0100] In Comparative Example 6, the corrosion-inhibiting emulsion did not contain 2-furan methylamine. 2-furan methylamine is the core source of the furan ring functional group. Without it, the corrosion-inhibiting emulsion loses its ability to chelate with metal ions to form a passivation film. The chemical active corrosion inhibition effect is completely lost, and it can only rely on polysilazane to provide a limited physical barrier and hydrophobicity. Under harsh corrosive environments, electrochemical corrosion at micro-defects is prone to occur and spread, and the corrosion protection performance is reduced.

[0101] In Comparative Example 7, the corrosion-inhibiting emulsion did not contain hexamethylcyclotrisilazane. Hexamethylcyclotrisilazane is the basic unit for constructing the polysilazane Si-O-Si three-dimensional network. Without it, a hydrophobic inorganic network cannot be formed, resulting in a decrease in the hydrophobicity and media resistance of the coating film. At the same time, it cannot form Si-O-Me covalent bonds with the metal substrate, leading to a sharp decrease in interfacial adhesion. The polymer formed by the remaining components has low cross-linking degree and is hydrophilic. The overall protection system degrades from dual chemical and physical protection to a single weak chemical corrosion inhibitor, with a greater performance degradation than in Comparative Example 6.

[0102] In Comparative Example 8, the slag filler preparation lacked potassium dihydrogen phosphate and the sintering temperature was insufficient. Potassium dihydrogen phosphate is a mineralizer and nucleating agent for the formation of microcrystalline glass phase. Insufficient sintering temperature prevents the densification of the phase structure. Both factors combined prevent the blast furnace slag and zeolite powder from forming a stable microcrystalline glass phase, resulting in a significant decrease in the chemical inertness and corrosion resistance of the filler itself. At the same time, the lack of phosphate passivation components leads to the loss of chemical passivation of the metal substrate. The filler will also undergo dissolution and pulverization in corrosive media, becoming a source of corrosion and causing the overall coating to break down and fall off.

[0103] In Comparative Example 9, the slag filler only uses etched powder. Boron nitride is the core of the shielding layer of the core-shell structure of the filler. Without it, the layered shielding effect cannot be formed, and the density and weather resistance of the coating surface decrease. At the same time, without the coupling and synergistic reinforcement of etched powder and boron nitride, the interface bonding between the filler and the resin is only physical interlocking. The interface bonding force is weak and interface separation is easy to occur. Moreover, the microporous structure of the etched powder is easy to absorb water and moisture, and the water resistance and damp heat resistance are further degraded.

[0104] In Comparative Example 10, the slag filler was prepared without boron nitride and dibutyltin dilaurate. The absence of boron nitride caused the filler to lose its layered shielding and weather-resistant reinforcement effect, resulting in a decrease in the UV resistance and damp heat resistance of the coating. Dibutyltin dilaurate is a catalyst for the condensation reaction between the KH-172 silane coupling agent and the hydroxyl groups on the filler surface after hydrolysis. Its absence resulted in extremely low modification efficiency of the coupling agent, making it impossible to form effective chemical bonds on the filler surface, leading to decreased interfacial compatibility and dispersibility, and an increase in internal defects in the coating. However, due to the partial physical interaction between the etching powder and the coupling agent, the performance degradation was relatively small.

Claims

1. An environmentally friendly water-based industrial anti-corrosion coating, characterized in that, The coating comprises the following raw materials in parts by weight: 40-45 parts of chlorinated ether resin emulsion, 10-14 parts of corrosion inhibitor emulsion, 5-8 parts of barrier agent, 12-16 parts of slag composite filler, 5-7 parts of amino-terminated hyperbranched polyamide crosslinking agent, 2.0-3.5 parts of composite film-forming aid, 1.5-2.0 parts of functional aid, 0.8-1.3 parts of synergistic aid, and the balance being deionized water; The preparation of the corrosion-inhibiting emulsion includes: mixing hexamethylcyclotrisilazane, glycidyl furfural ether, 2-furanylamine and isopropanol, reacting at 70-75°C under tetramethylammonium hydroxide catalysis until the epoxy value is below 0.01 mol / 100g, removing isopropanol under reduced pressure to obtain the reaction solution, then mixing and shearing emulsifying with deionized water and a composite emulsifier, adjusting the pH to 7.8-8.2 with dimethylethanolamine, and filtering to obtain the final product; The preparation of the barrier agent includes: adding lithium fluoride to hydrochloric acid and stirring, adding titanium aluminum carbide and stirring to peel off, centrifuging, washing the precipitate until neutral, dispersing it in an ethanol aqueous solution, adjusting the pH to 5.5-6.0, adding 3-aminopropyltriethoxysilane and stirring at 45-50°C, centrifuging, washing the precipitate, vacuum drying, and pulverizing through a 325-400 mesh sieve to obtain the barrier agent; The preparation of the slag composite filler includes: ball milling blast furnace slag powder, zeolite powder and potassium dihydrogen phosphate, sintering at 1000-1100℃ for 1-2 hours, crushing and sieving, dispersing in deionized water, adding citric acid for etching treatment to obtain etched powder; hydrolyzing boron nitride and KH-172 silane coupling agent in ethanol aqueous solution, adding the etched powder and dibutyltin dilaurate for reaction, centrifuging, washing and drying the solid, crushing and sieving to obtain the final product.

2. The environmentally friendly water-based industrial anti-corrosion coating according to claim 1, characterized in that, The composite film-forming aid includes dodecyl alcohol ester and diethylene glycol dimethyl ether in a mass ratio of 3:(1-1.5); the functional aid includes dispersant, defoamer and leveling agent in a mass ratio of (5-6):(2-3):(3-4); the synergistic aid includes sodium phytate and ammonium metavanadate in a mass ratio of 2:(1-1.5).

3. The environmentally friendly water-based industrial anti-corrosion coating according to claim 1, characterized in that, The viscosity of the coating is adjusted to 50-70 s using deionized water at a Forte 4 cup viscosity (25°C); the pH of the coating is adjusted to 7.8-8.2 using dimethylethanolamine.

4. The environmentally friendly water-based industrial anti-corrosion coating according to claim 1, characterized in that, In the preparation of the corrosion-inhibiting emulsion, the mass ratio of hexamethylcyclotrisilazane, glycidyl furfur ether, 2-furanmethylamine, isopropanol, tetramethylammonium hydroxide, deionized water, and composite emulsifier is (15-18):(20-25):(8-12):(15-20):(0.15-0.25):(65-75):(2.5-3.5); the composite emulsifier is prepared by mixing sucrose fatty acid ester and chitosan quaternary ammonium salt in a mass ratio of 2:(0.7-1).

5. An environmentally friendly water-based industrial anti-corrosion coating according to claim 1 or 4, characterized in that, The method for preparing the corrosion-inhibiting emulsion includes: mixing and stirring 15-18 parts by mass of hexamethylcyclotrisilazane, 20-25 parts by mass of glycidyl furfural ether, 8-12 parts by mass of 2-furanylamine, and 15-20 parts by mass of isopropanol; adding 0.15-0.25 parts by mass of tetramethylammonium hydroxide; reacting at 70-75°C for 5-6 hours; removing isopropanol by vacuum distillation to obtain a reaction solution; mixing and stirring 65-75 parts by mass of deionized water and 2.5-3.5 parts by mass of a composite emulsifier prepared from sucrose fatty acid ester and chitosan quaternary ammonium salt in a mass ratio of 2:0.7-1; adding the reaction solution; shear emulsifying; adjusting the pH to 7.8-8.2 with dimethylethanolamine; and filtering to obtain the corrosion-inhibiting emulsion.

6. The environmentally friendly water-based industrial anti-corrosion coating according to claim 1, characterized in that, In the preparation of the barrier agent, the mass ratio of lithium fluoride, hydrochloric acid, titanium aluminum carbide, aqueous ethanol solution, and 3-aminopropyltriethoxysilane is (5-8):(60-80):(8-10):(60-80):(2-4); the concentration of hydrochloric acid is 8.5-9.0 mol / L; and the concentration of aqueous ethanol solution is 50-60 vol.

7. An environmentally friendly water-based industrial anti-corrosion coating according to claim 1 or 6, characterized in that, The preparation method of the barrier agent includes: adding 5-8 parts by mass of lithium fluoride to 60-80 parts by mass of 8.5-9.0 mol / L hydrochloric acid, stirring at 1-6℃, adding 8-10 parts by mass of titanium aluminum carbide, stirring and exfoliating at 30-35℃ for 22-26 h, centrifuging, washing the precipitate with deionized water until neutral to obtain a solid, dispersing it in 60-80 parts by mass of 50-60 vol% ethanol aqueous solution, adjusting the pH to 5.5-6.0 with glacial acetic acid, adding 2-4 parts by mass of 3-aminopropyltriethoxysilane, stirring at 45-50℃ for 5.5-6.5 h, centrifuging, washing the precipitate and vacuum drying, pulverizing and passing through a 325-400 mesh sieve to obtain the barrier agent.

8. The environmentally friendly water-based industrial anti-corrosion coating according to claim 1, characterized in that, In the preparation of slag composite filler, the mass ratio of blast furnace slag powder, zeolite powder, and potassium dihydrogen phosphate is (20-30):(6-10):(1.2-1.8); the sintering is carried out at 1000-1100℃ for 1-2 hours; the amount of deionized water is 5-6 times the mass of the powder; the amount of citric acid added is 1-3% of the mass of the powder; the etching temperature is 60-65℃; and the amount of boron nitride used is equal to the amount of etching powder. The amount of KH-172 silane coupling agent is 3-5% of the mass of the etching powder; the amount of ethanol aqueous solution is 5-6 times the mass of the etching powder; the concentration of the ethanol aqueous solution is 50-60 vol%; the amount of dibutyltin dilaurate added is 0.05-0.1% of the mass of the etching powder; the reaction temperature is 70-75℃; and the mesh size of the sieve used for sieving is 650-800 mesh.

9. An environmentally friendly water-based industrial anti-corrosion coating according to claim 1 or 8, characterized in that, The preparation method of the slag composite filler includes: ball milling and mixing 20-30 parts by mass of blast furnace slag powder, 6-10 parts by mass of zeolite powder, and 1.2-1.8 parts by mass of potassium dihydrogen phosphate; sintering at 1000-1100℃ for 1-2 hours; cooling and then pulverizing through a 650-800 mesh sieve to obtain powder; dispersing the powder in 5-6 times its weight of deionized water; heating to 60-65℃; adding 1-3% by mass of citric acid to the powder; stirring and etching; centrifuging; washing the precipitate and then vacuum drying to obtain etched powder; Take 5-8% boron nitride by weight of the etching powder and disperse it in 50-60 vol% ethanol aqueous solution (5-6 times the weight of the etching powder). Add 3-5% KH-172 silane coupling agent by weight of the etching powder. Adjust the pH to 4.5-5.0 with glacial acetic acid and stir to hydrolyze. Then add the etching powder and 0.05-0.1% dibutyltin dilaurate by weight of the etching powder. Stir at 70-75℃, centrifuge, wash the precipitate, vacuum dry it, and pulverize it through a 650-800 mesh sieve to obtain slag composite filler.

10. The method for preparing an environmentally friendly water-based industrial anti-corrosion coating as described in claim 1, characterized in that, Includes the following steps: Functional additives were added to deionized water under stirring, followed by stirring. Slag composite filler was then added and sheared to disperse the coating, controlling the fineness of the coating to below 15 μm. Chlorinated ether resin emulsion, corrosion inhibitor emulsion, and barrier agent were added sequentially under stirring for dispersion. Composite film-forming aid and synergistic agent were added and stirred. Terminal amino hyperbranched polyamide crosslinking agent was added and stirred. The viscosity was adjusted with deionized water until the outflow time of a Forte 4 cup viscometer was 50–70 s. The pH was adjusted to 7.8–8.2 with dimethyl ethanolamine. The coating was degassed under vacuum and filtered to obtain the final coating.

Images