A water-based industrial anti-rust paint for steel components and its preparation method

Abstract

This invention relates to the field of waterborne coatings technology, specifically to a waterborne industrial anti-rust paint for steel components and its preparation method. This invention overcomes the problems of insufficient anti-rust performance and weak mechanical properties of existing waterborne industrial anti-rust paints. This invention achieves a synergistic effect of chemical anchoring and physical shielding by simultaneously bonding phosphate groups and graphene to the epoxy resin molecular chain; it significantly improves the mechanical properties of the coating film by using an organosilane coupling agent-modified waterborne polyamide curing agent to form an organic-inorganic interpenetrating network structure; it avoids the brittleness problem of pure epoxy systems by introducing a core-shell structured self-crosslinking acrylate emulsion, and the formed interpenetrating polymer network structure further enhances the density of the coating film; it forms an active-passive electrochemical synergistic protection with zinc-aluminum phosphate composite pigments by adding functionalized conductive polymer aqueous dispersions; and it enhances anti-rust performance by compounding zinc-aluminum phosphate composite pigments with glass powder.

Description

Technical Field

[0001] This invention relates to the field of water-based coatings technology, specifically to a water-based industrial anti-rust paint for steel components and its preparation method. Background Technology

[0002] Steel, as the most important structural material, is widely used in bridges, ships, vehicles, buildings, and machinery. However, it is highly susceptible to corrosion in complex environments such as humidity, acids, alkalis, and salt spray, which not only shortens the service life of components but can also lead to safety accidents and economic losses. Currently, commonly used anti-rust coatings for steel in the industrial field are mainly divided into two categories: solvent-based and water-based. Although solvent-based anti-rust paints have good anti-rust performance, they contain a large amount of volatile organic compounds, which can easily cause environmental pollution and harm the health of operators, failing to meet the current requirements of green and environmentally friendly industrial development. Water-based industrial anti-rust paints, due to their low VOC content and excellent environmental performance, are gradually becoming the mainstream development direction, but they still face two major technical challenges in practical applications.

[0003] First, their rust-preventive performance is insufficient. Traditional water-based rust-preventive paints mostly rely on single rust-preventive pigments (such as zinc phosphate and aluminum tripolyphosphate). These pigments have poor dispersion in the coating and are prone to uneven local concentrations, resulting in insufficient passivation of the steel surface by the coating. Rust spots appear in a short period of time under salt spray conditions, making it difficult to meet the rust prevention requirements of marine engineering, heavy machinery, and other long-term outdoor or harsh environments. Second, their mechanical properties are weak. The film-forming substances of water-based paints are mostly acrylic emulsions and epoxy resin emulsions. Coatings formed by these resins have problems such as low hardness, poor adhesion, and insufficient impact resistance. During the transportation, installation, and use of components, the coating is prone to scratches and peeling, thus losing its rust-preventive protection.

[0004] To address these issues, existing technologies often employ methods such as increasing the amount of rust-preventive pigments or using composite resins. However, the former leads to increased coating viscosity and decreased workability, and excessive pigments can cause stress concentration within the coating, further reducing mechanical properties. The latter, due to poor compatibility between different resins, is prone to delamination and uneven film formation, failing to achieve a synergistic improvement in rust prevention and mechanical properties. Furthermore, some technologies attempt to introduce nano-modified materials, but nanoparticles tend to agglomerate, making uniform dispersion in aqueous systems difficult and hindering their ability to fully enhance coating performance. Therefore, developing a water-based industrial rust-preventive paint for steel components that combines excellent rust prevention and mechanical properties with environmental friendliness and good workability has become a critical issue urgently needing resolution in this field. To this end, a water-based industrial rust-preventive paint for steel components and its preparation method are proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a water-based industrial anti-rust paint for steel components and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] Unless otherwise specified, all “parts” in this invention refer to “parts by weight”.

[0008] This invention provides a method for preparing a water-based industrial anti-rust paint for steel components. The preparation method is as follows: 20 parts of deionized water, 1.5 parts of wetting and dispersing agent, and 0.8 parts of defoamer are added sequentially to a dispersion vessel and stirred evenly. Then, 8-20 parts of zinc aluminum phosphate composite pigment and 2-8 parts of glass powder are added and dispersed at 2000 rpm for 30-45 minutes to obtain a pigment slurry. Under stirring at 1000 rpm, 30-50 parts of water-based resin emulsion, 5-15 parts of core-shell self-crosslinking acrylate emulsion, 1-5 parts of conductive polymer aqueous dispersion, 0.5 parts of leveling agent, and 0.4 parts of thickener are added sequentially and stirred for 30 minutes to obtain component A. Component A is mixed with 10-20 parts of component B at a mass ratio to obtain the water-based industrial anti-rust paint. The glass powder is B1000A glass powder, the wetting and dispersing agent is BYK-190, the defoamer is BYK-024, the leveling agent is BYK-346, and the thickener is RM-8W.

[0009] The core-shell self-crosslinking acrylate emulsion was prepared according to the method in Example 4 of CN113292682B;

[0010] Component B is a curing agent, which is obtained by modifying waterborne polyamide with a silane coupling agent;

[0011] The conductive polymer aqueous dispersion was prepared from aniline and polystyrene sulfonic acid.

[0012] Preferably, the aqueous resin emulsion is one of the following: modified aqueous epoxy resin emulsion, aqueous acrylic copolymer emulsion, and aqueous alkyd resin emulsion; the aqueous acrylic copolymer emulsion is model WANTIPRO-0620, and the aqueous alkyd resin emulsion is model 3AK0240B.

[0013] The preferred method for preparing the modified waterborne epoxy resin emulsion is as follows: 1.2 parts of graphene oxide are dispersed in 20 parts of deionized water and ultrasonically treated at 300-350W for 50 min to obtain a graphene oxide dispersion; under nitrogen protection, 45 parts of epoxy resin and 3.5-4.5 parts of phosphoric acid are subjected to ring-opening esterification reaction in 15 parts of propylene glycol methyl ether acetate to generate a phosphorus-containing epoxy prepolymer; the graphene oxide dispersion is added to the phosphorus-containing epoxy prepolymer, and the mixture is heated to 80℃ and reacted for 1.5-2 h to allow the oxygen-containing functional groups on the graphene surface to react with the epoxy groups, chemically bonding the graphene to the epoxy resin chain; 3 parts of emulsifier and 25 parts of deionized water are added, and the mixture is subjected to reverse emulsification under high-speed shearing, followed by vacuum distillation to obtain the modified waterborne epoxy resin emulsion; the epoxy resin type is 3EE104W.

[0014] Preferably, the emulsifier is obtained by compounding a nonionic emulsifier and anionic emulsifier at a mass ratio of 3:1; the nonionic emulsifier is OP-10; and the anionic emulsifier is sodium dodecylbenzenesulfonate.

[0015] The preferred method for preparing the zinc-aluminum phosphate composite pigment is as follows: Dissolve 18 parts zinc sulfate and 9 parts aluminum sulfate in 70 parts deionized water to obtain a metal salt solution; add 0.4 parts hexadecyltrimethylammonium bromide to 50 parts deionized water, heat to 40°C and stir for 25 minutes, cool to room temperature, and then add 10 parts phosphoric acid dropwise. After the addition is complete, continue stirring for 10 minutes to obtain a phosphate solution; simultaneously add the metal salt solution and the phosphate solution dropwise into the deionized water, while dynamically adjusting the pH of the system using 3M sodium hydroxide solution to maintain it between 6.0 and 7.0. After stirring for 30 minutes, a precipitate slurry is formed. The precipitate slurry is transferred to a high-pressure reactor, sealed, and placed in an oven for hydrothermal reaction at 160-200℃ for 12-24 hours. After the reactor cools naturally to room temperature, the solid product is collected by centrifugation at 8000rpm for 15 minutes. The product is washed three times alternately with deionized water and anhydrous ethanol and then dried in a vacuum drying oven at 70℃ for 12 hours. Finally, the product is pulverized for 5 minutes using an air jet mill (air pressure 0.6-0.8MPa, feed rate 50g / min) to obtain zinc aluminum phosphate composite pigment.

[0016] Preferably, the preparation method of the conductive polymer aqueous dispersion is as follows: 6-8 parts of aniline are added to a distillation flask, and the fraction is collected by vacuum distillation to obtain distilled aniline; 8-10 parts of polystyrene sulfonic acid are dissolved in 40 parts of deionized water to obtain a template solution, which is cooled to 0-5℃ in an ice-water bath; distilled aniline is added dropwise at 1000 rpm and stirred for 30 min to obtain a mixed solution; ammonium persulfate aqueous solution is added to the mixed solution and stirred for 12-20 h to obtain a complex. During the dropwise addition, the solution color gradually changes from colorless to light blue, and finally to dark green; the complex is transferred to a dialysis bag and dialyzed in deionized water to obtain the conductive polymer aqueous dispersion.

[0017] Preferably, the curing agent is prepared as follows: 10-15 parts of silane coupling agent KH560 are mixed with 8 parts of anhydrous ethanol to obtain a mixture; 80 parts of aqueous polyamide are added to a reaction vessel, heated to 40°C, stirred at 400 rpm for 10 min, and then the mixture is added dropwise at a rate of 2 mL / min; after the dropwise addition is completed, the temperature is raised to 50-60°C, 5 parts of deionized water are added and stirring is continued for 1.8-2.5 h, then the temperature is lowered to 25°C, and the curing agent is obtained by filtration.

[0018] Another aspect of the present invention provides a water-based industrial anti-rust paint for steel components, wherein the water-based industrial anti-rust paint is prepared by any of the above preparation methods; the raw materials for preparing the water-based industrial anti-rust paint include water-based resin emulsion, core-shell structure self-crosslinking acrylate emulsion, conductive polymer aqueous dispersion, zinc aluminum phosphate composite pigment, glass powder and curing agent.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. This invention simultaneously bonds phosphate groups and graphene to the epoxy resin molecular chain. The introduction of phosphate groups, on the one hand, utilizes their acidity to react with the oxides on the surface of the steel substrate to form a dense phosphate complex layer, which greatly enhances the chemical adhesion between the coating and the substrate; on the other hand, phosphate ions themselves are excellent anodic corrosion inhibitors, while the two-dimensional sheet-like graphene can form a "maze effect" in the resin matrix, which physically greatly extends the penetration path of corrosive media (water, oxygen, chloride ions, etc.); and the chemical anchoring effect provided by phosphate groups and the physical shielding effect provided by graphene are superimposed to form a chemical-physical dual protection system: phosphate groups enhance interfacial bonding and avoid interfacial corrosion caused by insufficient adhesion; graphene blocks the intrusion of external corrosive media. The synergistic effect of the two achieves a rust prevention effect of 1+1>2.

[0021] 2. This invention utilizes an organosilane coupling agent-modified waterborne polyamide curing agent. During the curing process, the amine groups of the polyamide react with the epoxy groups of the modified epoxy resin to form a basic cross-linked network. Simultaneously, the silane groups grafted onto the polyamide hydrolyze into active silanol groups. These silanol groups can undergo dehydration condensation reactions with the hydroxyl groups on the surface of the steel substrate to form strong chemical bonds, further enhancing the coating adhesion. Furthermore, the silanol groups can also self-condense, interpenetrating within the epoxy-polyamide network to form a rigid silicon-oxygen inorganic network structure. This organic-inorganic interpenetrating network structure significantly improves the cross-linking density and hardness of the coating.

[0022] 3. This invention introduces a core-shell structured self-crosslinking acrylate emulsion. During film formation, the emulsion particles are uniformly distributed in the epoxy curing network as a toughening dispersed phase. Its soft-shell structure endows the coating with excellent flexibility and elasticity, enabling it to absorb and dissipate impact energy, significantly improving the impact resistance and crack resistance of the coating, and effectively overcoming the brittleness problem of the pure epoxy system. In addition, the emulsion, through its own silane functional groups, undergoes hydrolysis and self-crosslinking under the action of water to form a highly stable -Si-O-Si-inorganic network. This network interpenetrates with the external epoxy-polyamide curing network, forming an interpenetrating polymer network structure, which can further enhance the density of the coating, reduce water absorption, and thus strengthen the physical barrier against corrosion.

[0023] 4. The formulation of this invention incorporates a functionalized conductive polymer aqueous dispersion, which possesses certain conductivity and redox reversibility. When a micro-corrosion cell forms on the steel surface, the conductive polymer can rapidly transfer electrons and passivate the steel substrate within a potential range that is less prone to corrosion. It works synergistically with the zinc-aluminum phosphate composite pigment, which acts as a corrosion inhibitor: the zinc-aluminum phosphate slowly hydrolyzes to release phosphate and zinc ions, providing corrosion inhibition in both the anodic and cathodic regions, while the conductive polymer provides electrochemical passivation protection. When minor damage occurs to the coating, the conductive polymer can "sensor" the potential change and passivate a large area of ​​the substrate, while the zinc-aluminum phosphate provides localized chemical corrosion inhibition at the damage point. This synergistic mechanism of "active passivation" and "passive corrosion inhibition" significantly enhances the coating's salt spray resistance and long-term corrosion protection.

[0024] 5. This invention employs two fillers with different forms and properties: zinc aluminum phosphate composite pigment and glass powder. During the coating drying process, both align parallel to the substrate surface due to surface tension. The zinc aluminum phosphate flakes are larger in diameter and primarily function as corrosion inhibitors and initial shielding agents; while the smaller glass powder fills the gaps between the larger pigment flakes, forming a multi-scale, high-density overlapping structure of "large flakes bridging and small flakes filling." This structure significantly reduces the porosity of the coating, forming a denser and more tortuous physical shielding layer than a single filler, thus improving rust prevention performance; simultaneously, the high hardness of the glass powder itself further enhances the scratch and wear resistance of the coating. Attached Figure Description

[0025] Figure 1 The figures show the hardness test results of Examples 4, 6-7, and Comparative Examples 3-5 of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0027] Please see Figure 1 This invention provides a water-based industrial anti-rust paint for steel components and its preparation method. The technical solution is as follows:

[0028] Preparation Example 1

[0029] 1.2 parts of graphene oxide were dispersed in 20 parts of deionized water and sonicated at 300W for 50 min to obtain a graphene oxide dispersion. Under nitrogen protection, 45 parts of epoxy resin were added to 15 parts of propylene glycol methyl ether acetate, the mixture was heated to 70℃ and stirred for 30 min at a stirring rate of 300 rpm. 3.5 parts of phosphoric acid were added dropwise at a dropping rate of 0.8 mL / min, with the stirring rate increased to 500 rpm during the addition. After the addition was completed, the temperature was raised to 85℃ and the reaction was maintained at this temperature for 2 minutes. h, a phosphorus-containing epoxy prepolymer is generated; the graphene oxide dispersion is added to the phosphorus-containing epoxy prepolymer, the temperature is raised to 80℃ and reacted for 1.5h, the temperature is lowered to 50℃, the stirring speed is adjusted to 600rpm, 3 parts of emulsifier are added and stirred for 30min, the stirring speed is increased to 1000rpm, 25 parts of deionized water are added for reverse emulsification, and the modified waterborne epoxy resin emulsion is obtained by vacuum distillation; the emulsifier is obtained by compounding OP-10 and sodium dodecylbenzenesulfonate at a mass ratio of 3:1.

[0030] Preparation Example 2

[0031] A modified waterborne epoxy resin emulsion was prepared according to the method of Preparation Example 1, except that the ultrasonic power was 320W, the amount of phosphoric acid was 4 parts, the graphene oxide dispersion was added to the phosphorus-containing epoxy prepolymer, and the temperature was raised to 80°C and reacted for 1.8h.

[0032] Preparation Example 3

[0033] A modified waterborne epoxy resin emulsion was prepared according to the method of Preparation Example 1, except that the ultrasonic power was 350W, the amount of phosphoric acid was 4.5 parts, the graphene oxide dispersion was added to the phosphorus-containing epoxy prepolymer, and the temperature was raised to 80°C and reacted for 2 hours.

[0034] Example 1

[0035] 18 parts zinc sulfate and 9 parts aluminum sulfate were dissolved in 70 parts deionized water to obtain a metal salt solution. 0.4 parts hexadecyltrimethylammonium bromide were added to 50 parts deionized water, the mixture was heated to 40°C and stirred for 25 min, cooled to room temperature, and then 10 parts phosphoric acid were added dropwise. After the addition was complete, stirring was continued for 10 min to obtain a phosphate solution. The metal salt solution and phosphate solution were simultaneously added dropwise to deionized water, while the pH of the system was dynamically adjusted using 3M sodium hydroxide solution to maintain it between 6.0 and 7.0. After the addition was complete, stirring was continued for 30 min to form a precipitate slurry. The precipitate slurry was transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, sealed, and placed in an oven for hydrothermal reaction at 160°C for 12 h. After the reactor cooled naturally to room temperature, the solid product was collected by centrifugation at 8000 rpm for 15 min, washed three times alternately with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven at 70°C for 12 h. Finally, the product was pulverized for 5 min using an air jet mill to obtain a zinc-aluminum phosphate composite pigment.

[0036] Six parts of aniline were added to a distillation flask and distilled under reduced pressure at 0.08 MPa and 60 °C to collect the distillate, yielding distilled aniline. Eight parts of polystyrene sulfonic acid were dissolved in 40 parts of deionized water to obtain a template solution, which was cooled to 0-5 °C in an ice-water bath (maintained at this temperature until polymerization was complete). Distilled aniline was added dropwise at 1000 rpm and stirred for 30 min to obtain a mixed solution. An ammonium persulfate aqueous solution was added to the mixed solution and stirred for 12 h to obtain a composite. The composite was transferred to a dialysis bag and dialyzed in deionized water until the dialyzed water was neutral and its conductivity remained unchanged, yielding a conductive polymer aqueous dispersion. The ammonium persulfate aqueous solution was obtained by dissolving 7 parts of ammonium persulfate in 20 parts of deionized water. The dropping rate of the ammonium persulfate aqueous solution was 0.5 mL / min.

[0037] Ten parts of silane coupling agent KH560 were mixed with eight parts of anhydrous ethanol to obtain a mixture. Eighty parts of aqueous polyamide were added to a reaction vessel, heated to 40°C, and stirred at 400 rpm for 10 min. The mixture was then added dropwise at a rate of 2 mL / min, and the stirring rate was increased to 500 rpm. After the dropwise addition was completed, the temperature was raised to 50°C, five parts of deionized water were added, and stirring was continued for 1.8 h. The temperature was then lowered to 25°C, and the mixture was filtered through a 100-mesh filter to obtain the curing agent.

[0038] 20 parts deionized water, 1.5 parts wetting and dispersing agent, and 0.8 parts defoamer were added sequentially to a dispersion vessel and stirred evenly. Then, 8 parts zinc aluminum phosphate composite pigment and 2 parts glass powder were added and dispersed at 2000 rpm for 30 minutes to obtain a pigment slurry. Under stirring at 1000 rpm, 30 parts waterborne resin emulsion, 5 parts core-shell self-crosslinking acrylate emulsion, 1 part conductive polymer aqueous dispersion, 0.5 parts leveling agent, and 0.4 parts thickener were added sequentially and stirred for 30 minutes to obtain component A. Component A was mixed with 10 parts of component B at a mass ratio to obtain a waterborne industrial anti-rust paint. Component B is a curing agent. The waterborne resin emulsion is a waterborne acrylic copolymer emulsion, model WANTIPRO-0620.

[0039] Example 2

[0040] The preparation method and parameters were the same as in Experiment 1, except that the amount of waterborne resin emulsion was 40 parts, the type of waterborne resin was waterborne alkyd resin emulsion, model 3AK0240B, and the amount of core-shell self-crosslinking acrylate emulsion was 8 parts.

[0041] Example 3

[0042] The preparation method and parameters were the same as in Experimental Example 1, except that the amount of waterborne resin emulsion was 50 parts, the type of waterborne resin was modified waterborne epoxy resin emulsion, which was prepared in Preparation Example 1, and the amount of core-shell self-crosslinking acrylate emulsion was 10 parts.

[0043] Example 4

[0044] The preparation method and parameters were the same as in Experimental Example 1, except that the amount of waterborne resin emulsion was 45 parts, the type of waterborne resin was modified waterborne epoxy resin emulsion, which was prepared in Preparation Example 2, and the amount of core-shell self-crosslinking acrylate emulsion was 12 parts.

[0045] Example 5

[0046] The preparation method and parameters were the same as in Experimental Example 1, except that the amount of waterborne resin emulsion was 45 parts, the type of waterborne resin was modified waterborne epoxy resin emulsion, which was prepared in Preparation Example 3, and the amount of core-shell self-crosslinking acrylate emulsion was 15 parts.

[0047] Comparative Example 1

[0048] The preparation method and parameters were the same as in Experiment 4, except that the waterborne epoxy resin emulsion was not modified.

[0049] Comparative Example 2

[0050] The preparation method and parameters of Example 4 were used, except that no core-shell self-crosslinking acrylate emulsion was added.

[0051] Experiment Example 1: Mechanical Properties and Rust Prevention Test

[0052] Salt water resistance was tested according to GB / T9274 standard; salt spray resistance was tested according to GB / T1771 standard; adhesion was tested according to GB / T1720 standard; impact strength was tested according to GB / T1732 standard; the results are shown in Table 1.

[0053] Table 1 Mechanical and rust-preventive performance tests of Examples 1-5 and Comparative Examples 1-2

[0054] Group Salt water resistance (3% NaCl), 480h Salt spray resistance, 480h Adhesion / Grade Impact strength / cm Example 1 No bubbling, no wrinkling, no peeling, slight discoloration No bubbling, no wrinkling, no peeling, slight discoloration 1 50 Example 2 No bubbling, no wrinkling, no peeling, slight discoloration No bubbling, no wrinkling, no peeling, slight discoloration 1 50 Example 3 No bubbling, no wrinkling, no peeling, slight discoloration No bubbling, no wrinkling, no peeling, slight discoloration 1 50 Example 4 No abnormalities No abnormalities 1 55 Example 5 No abnormalities No bubbling, no wrinkling, no peeling, slight discoloration 1 55 Comparative Example 1 Pitting and bubbling Slight discoloration 3 25 Comparative Example 2 Rust and wrinkles A few white spots 2 35

[0055] As shown in Table 1, the water-based industrial anti-rust paints prepared in Examples 1-5 all exhibited superior mechanical and anti-rust properties compared to the comparative examples. Among them, the water-based industrial anti-rust paint prepared in Example 4 showed the best performance, exhibiting no abnormalities in a 3% NaCl-containing salt solution for 480 hours, no abnormalities in a salt spray test for 480 hours, an adhesion grade of 1, and an impact strength of 50 cm. In the modified water-based epoxy resin emulsion, the physical barrier layer structure of graphene oxide can block water, oxygen, and Cl-. -The penetration pathways of corrosive media; phosphorus can react with the surface of metal substrates (such as steel) to form a phosphate passivation film, inhibiting anodic dissolution; and the nano-reinforcing effect of graphene oxide can improve the mechanical strength of epoxy resin, and its surface hydroxyl groups can form hydrogen bonds with the curing agent to enhance the crosslinking density inside the paint film. The flexible segments of phosphorus-containing epoxy prepolymer can alleviate impact stress; in Comparative Example 1, the waterborne epoxy resin emulsion was not modified, which made it easy for corrosive media to penetrate the paint film, and the crosslinking density was low, the interfacial bonding was weak, and the mechanical properties decreased significantly. The flexible core of the core-shell self-crosslinking acrylic emulsion can absorb impact energy, preventing the paint film from failing due to brittle fracture. The rigid shell can form an interpenetrating network with waterborne epoxy resin and curing agent, improving the overall crosslinking degree and adhesion of the paint film. Furthermore, the emulsion, through its own silane functional groups, undergoes hydrolysis and self-crosslinking under the action of water, forming a highly stable -Si-O-Si-inorganic network. This network interpenetrates with the external epoxy-polyamide curing network, constituting an interpenetrating polymer network structure, which can further enhance the density of the coating film, reduce water absorption, and thus strengthen the physical barrier against corrosion. In Comparative Example 2, without the addition of the core-shell self-crosslinking acrylic emulsion, the paint film brittleness increased, density decreased, and rust prevention durability weakened. However, due to the presence of graphene oxide and phosphorus modification, its performance was better than that of Comparative Example 1.

[0056] Example 6

[0057] Referring to the preparation method and parameters of Experiment Example 4, the difference is that when preparing the curing agent, the amount of silane coupling agent KH560 is 12 parts, the temperature is raised to 55°C after the mixture is added dropwise, 5 parts of deionized water are added and stirring is continued for 2.2 hours; the amount of curing agent is 15 parts.

[0058] Example 7

[0059] Referring to the preparation method and parameters of Experiment 4, the difference is that when preparing the curing agent, the amount of silane coupling agent KH560 is 15 parts, the temperature is raised to 60°C after the mixture is added dropwise, 5 parts of deionized water are added and stirring is continued for 2.5 hours; the amount of curing agent is 20 parts.

[0060] Comparative Example 3

[0061] The preparation method and parameters were the same as in Experiment 4, except that no silane coupling agent was used to modify the waterborne polyamide.

[0062] Comparative Example 4

[0063] Referring to the preparation method and parameters of Experiment Example 4, the difference is that component A was not prepared in steps, but all components were mixed at the same time, and then stirred at 2000 rpm for 30 min to obtain water-based industrial anti-rust paint.

[0064] Comparative Example 5

[0065] Referring to the preparation method and parameters of Experiment Example 4, the difference is that component A and component B were not prepared separately. Instead, when preparing component A, the curing agent, leveling agent, and thickener were added together.

[0066] Experiment Example 2 Mechanical Performance Testing

[0067] The adhesion was tested according to GB / T1720 standard; the hardness was tested according to GB / T1730 standard; the results are shown in Table 2.

[0068] Table 2 Mechanical property tests of Examples 4, 6-7 and Comparative Examples 3-5

[0069] Group Adhesion / Grade hardness Example 4 1 0.46 Example 6 1 0.50 Example 7 1 0.49 Comparative Example 3 3 0.36 Comparative Example 4 2 0.42 Comparative Example 5 4 0.30

[0070] As shown in Table 2, in Examples 4 and 6-7, by using an organosilane coupling agent-modified waterborne polyamide curing agent, during the curing process, the amine groups of the polyamide react with the epoxy groups of the modified epoxy resin to form a basic crosslinking network. Simultaneously, the silane groups grafted onto the polyamide hydrolyze into active silanol groups. These silanol groups can undergo dehydration condensation with the hydroxyl groups on the surface of the steel substrate to form strong chemical bonds, further enhancing the coating adhesion. Furthermore, the silanol groups can also self-condense, interpenetrating within the epoxy-polyamide network to form a rigid silicon-oxygen inorganic network structure. This organic-inorganic interpenetrating network structure significantly improves the crosslinking density and hardness of the coating, resulting in improved mechanical properties of the rust-preventive paint. The adhesion is grade 1, and the hardness is 0.46-0.50. In Comparative Example 3, the waterborne polyamide was not modified with a silane coupling agent, making it unable to form chemical bonds with the pigments and substrate. It relied solely on physical adsorption for bonding, resulting in decreased interfacial adhesion between the paint film and the substrate, fewer crosslinking points, a loose internal structure, and reduced resistance to hard object indentation and deformation. In Comparative Example 4, component A was not prepared in steps; instead, all components were mixed simultaneously, followed by stirring at 2000 rpm for 30 minutes. This resulted in insufficient dispersion of the pigments at high speeds, leading to the formation of agglomerated particles. These particles created stress concentration points within the paint film, making it prone to breaking the interface between the paint film and the substrate under stress, thus reducing adhesion. Furthermore, the high speed directly acting on the resin emulsion damaged the resin molecular chain structure, leading to incomplete crosslinking reactions. Simultaneously, pigment agglomeration caused uneven density within the paint film, reducing its resistance to deformation. In Comparative Example 5, components A and B were not prepared separately. Instead, the curing agent, leveling agent, and thickener were added together when preparing component A. This resulted in partial pre-crosslinking during the preparation stage, forming "partially crosslinked gel particles." These particles could not fully wet and bond with the substrate surface, leading to a significant decrease in interfacial bonding. Furthermore, the premature pre-crosslinking consumed some of the curing agent, resulting in incomplete crosslinking reaction after the subsequent mixing of A and B, and a decrease in the crosslinking density inside the paint film.

[0071] Example 8

[0072] Referring to the preparation method and parameters of Experiment 6, the difference is that when preparing the conductive polymer aqueous dispersion, the amount of aniline is 7 parts, the amount of polystyrene sulfonic acid is 9 parts, and the ammonium persulfate aqueous solution is added to the mixed solution and stirred for 16 hours to obtain the composite; the amount of zinc aluminum phosphate composite pigment is 14 parts, the amount of glass powder is 5 parts, and it is dispersed at 2000 rpm for 40 minutes to obtain the pigment slurry; the amount of conductive polymer aqueous dispersion is 3 parts.

[0073] Example 9

[0074] Referring to the preparation method and parameters of Experiment 6, the difference is that when preparing the conductive polymer aqueous dispersion, the amount of aniline is 8 parts, the amount of polystyrene sulfonic acid is 10 parts, and the ammonium persulfate aqueous solution is added to the mixed solution and stirred for 20 hours to obtain the composite; the amount of zinc aluminum phosphate composite pigment is 20 parts, the amount of glass powder is 8 parts, and the pigment slurry is obtained by dispersing at 2000 rpm for 45 minutes; the amount of conductive polymer aqueous dispersion is 5 parts.

[0075] Comparative Example 6

[0076] The preparation method and parameters were the same as in Experiment 6, except that no conductive polymer aqueous dispersion was added.

[0077] Comparative Example 7

[0078] The preparation method and parameters were the same as in Experiment 6, except that no glass powder was added.

[0079] Comparative Example 8

[0080] The preparation method and parameters were the same as in Experiment 6, except that the zinc aluminum phosphate composite pigment was replaced with zinc phosphate and aluminum tripolyphosphate in a ratio of 2:1, while the total amount of pigment remained the same.

[0081] Experiment Example 3: Rust Prevention Performance Test

[0082] Salt spray resistance was tested according to the method in Experiment Example 1; the results are shown in Table 3.

[0083] Table 3 Rust prevention performance tests of Examples 6, 8-9 and Comparative Examples 6-8

[0084] Group Acid resistance (5% HCl) 25℃, 30 days Alkali resistance (5% NaOH) 25℃, 30d Salt spray resistance Example 6 No bubbling or peeling No bubbling or peeling No abnormalities Example 8 No bubbling or peeling No bubbling or peeling No abnormalities Example 9 No bubbling or peeling No bubbling or peeling No abnormalities Comparative Example 6 Localized detachment Localized blistering Localized wrinkling and peeling Comparative Example 7 flakes Large area of ​​bubbles wrinkling and peeling Comparative Example 8 Localized detachment Localized blistering Localized wrinkling

[0085] As shown in Table 3, in Examples 6 and 8-9, a functionalized conductive polymer aqueous dispersion was added to the formulation, which possesses certain conductivity and redox reversibility. When a micro-corrosion cell forms on the steel surface, the conductive polymer can rapidly transfer electrons and passivate the steel substrate within a potential range that is not easily corroded. It forms a synergistic mechanism of "active passivation" and "passive corrosion inhibition" with the zinc aluminum phosphate composite pigment, which acts as a corrosion inhibitor. Simultaneously, the zinc aluminum phosphate composite pigment and glass powder, two fillers with different forms and properties, form a multi-scale, high-density overlapping structure of "large-area bridging and small-area filling," reducing the porosity of the coating film and forming a denser and more tortuous physical shielding layer than a single filler, thus improving rust prevention performance. The resulting rust-preventive paint exhibits excellent resistance to acid and alkali corrosion. Conductive polymers can regulate the surface potential of metal substrates through electron transfer, inhibiting anodic oxidation. Furthermore, their polymer chains can fill the pores in the paint film, reducing the penetration of corrosive media. In Comparative Example 6, without the addition of a conductive polymer aqueous dispersion, the dual effect of the paint film's "electrochemical protection" and "physical barrier" is weakened. In a 5% HCl solution, H... + It easily penetrates the paint film and reacts with the metal substrate to generate H2. Without the potential-modulating effect of the conductive polymer, the anodic dissolution rate is accelerated. In a 5% NaOH solution, the paint film without the added conductive polymer has higher porosity. - Easy penetration leads to swelling of the paint film, and it also fails to help the substrate form a stable passivation film; in a neutral salt spray environment, Cl - Increased penetration rate.

[0086] In Comparative Example 7, without the addition of glass powder, the physical barrier effect of the paint film was significantly weakened, allowing corrosive media to easily penetrate the paint film and contact the substrate. In a 5% HCl solution, the pores of the paint film without glass powder exhibited a "linear" shape. + The penetration distance is shortened; in 5% NaOH solution, the anti-swelling ability of the paint film without glass powder decreases, and at the same time, OH... - The permeation rate is accelerated; in a neutral salt spray environment, there is no "labyrinth barrier" without glass powder, Cl - Moisture can quickly reach the substrate surface. Zinc-aluminum phosphate is a single composite phase with synergistic passivation function: zinc ions and aluminum ions react together with the substrate to form a dense zinc-aluminum phosphate composite passivation film. In Comparative Example 8, the zinc-aluminum phosphate composite pigment was replaced with zinc phosphate and aluminum tripolyphosphate in a ratio of 2:1. The total amount of pigment remained unchanged. The mixed pigments were physically mixed and had no synergistic effect. Furthermore, the passivation film was not dense enough, resulting in a decrease in rust prevention performance.

[0087] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a water-based industrial anti-rust paint for steel components, characterized in that: The preparation method is as follows: Deionized water, wetting and dispersing agent, and defoamer are mixed and stirred evenly. Zinc aluminum phosphate composite pigment and glass powder are added and dispersed to obtain a pigment slurry. Aqueous resin emulsion, core-shell self-crosslinking acrylate emulsion, and conductive polymer aqueous dispersion are added and stirred to obtain component A. Component A is mixed with component B to obtain the water-based industrial anti-rust paint. Component B is a curing agent, obtained by modifying water-based polyamide with a silane coupling agent. The conductive polymer aqueous dispersion was prepared from aniline and polystyrene sulfonic acid; The aqueous resin emulsion is a modified aqueous epoxy resin emulsion. The preparation method of the modified aqueous epoxy resin emulsion is as follows: 1.2 parts of graphene oxide are dispersed in 20 parts of deionized water and ultrasonically treated at 300-350W for 50 min to obtain a graphene oxide dispersion; under nitrogen protection, 45 parts of epoxy resin and 3.5-4.5 parts of phosphoric acid are reacted in 15 parts of propylene glycol methyl ether acetate to generate a phosphorus-containing epoxy prepolymer; the graphene oxide dispersion is added to the phosphorus-containing epoxy prepolymer, and the mixture is heated to 80℃ and reacted for 1.5-2 h; after the reaction, 3 parts of emulsifier and 25 parts of deionized water are added for reverse emulsification, and the modified aqueous epoxy resin emulsion is obtained by vacuum distillation. The conductive polymer aqueous dispersion is prepared as follows: 6-8 parts of the aniline are distilled under reduced pressure to collect the fraction, obtaining distilled aniline; 8-10 parts of the polystyrene sulfonic acid are dissolved in 40 parts of deionized water to obtain a template solution; after cooling, the distilled aniline is added dropwise at 1000 rpm and stirred for 30 min to obtain a mixed solution; an ammonium persulfate aqueous solution is added to the mixed solution and stirred for 12-20 h to obtain a complex; the complex is dialyzed to obtain the conductive polymer aqueous dispersion.

2. The method for preparing a water-based industrial anti-rust paint for steel components according to claim 1, characterized in that: The emulsifier is obtained by compounding a nonionic emulsifier and anionic emulsifier at a mass ratio of 3:1; the nonionic emulsifier is OP-10; and the anionic emulsifier is sodium dodecylbenzenesulfonate.

3. The method for preparing a water-based industrial anti-rust paint for steel components according to claim 1, characterized in that: The preparation method of the zinc-aluminum phosphate composite pigment is as follows: 18 parts of zinc sulfate and 9 parts of aluminum sulfate are dissolved in 70 parts of deionized water to obtain a metal salt solution; 0.4 parts of hexadecyltrimethylammonium bromide are added to 50 parts of deionized water, the temperature is raised to 40℃ and stirred for 25 min, and after cooling to room temperature, 10 parts of phosphoric acid are added dropwise. After the addition is completed, stirring is continued for 10 min to obtain a phosphate solution; the metal salt solution and the phosphate solution are simultaneously added dropwise to deionized water, and the pH value of the system is adjusted using 3M sodium hydroxide solution to maintain it between 6.0 and 7.

0. After the addition is completed, stirring is carried out for 30 min to obtain a precipitate slurry; the precipitate slurry is transferred to a high-pressure reactor, sealed, and placed in an oven for hydrothermal reaction at 160-200℃ for 12-24 h, centrifuged, washed, and dried to obtain the zinc-aluminum phosphate composite pigment.

4. The method for preparing a water-based industrial anti-rust paint for steel components according to claim 1, characterized in that: The curing agent is prepared as follows: 10-15 parts of the silane coupling agent are mixed with 8 parts of anhydrous ethanol to obtain a mixture; 80 parts of the aqueous polyamide are added to a reaction vessel, heated to 40°C, stirred at 400 rpm for 10 min, and then the mixture is added dropwise at a rate of 2 mL / min; after the dropwise addition is completed, the temperature is raised to 50-60°C, 5 parts of deionized water are added and stirring is continued for 1.8-2.5 h, then the temperature is lowered to 25°C, and the curing agent is obtained by filtration.

5. A water-based industrial anti-rust paint for steel components, characterized in that: The water-based industrial anti-rust paint is prepared by the preparation method described in any one of claims 1-4; the raw materials for preparing the water-based industrial anti-rust paint include water-based resin emulsion, core-shell self-crosslinking acrylate emulsion, conductive polymer aqueous dispersion, zinc aluminum phosphate composite pigment, glass powder, and curing agent.

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