Water-based anticorrosive primer and preparation method thereof

Abstract

The invention relates to the technical field of water-based anticorrosive primer coating, in particular to water-based anticorrosive primer and a preparation method thereof. The water-based anticorrosive primer is prepared from the following preparation raw materials in parts by mass: 45 to 50 parts of water-based epoxy resin emulsion, 15 to 18 parts of curing agent, 0.2 to 0.5 part of wetting agent, 8 to 12 parts of surface calcium ionization modified anti-rust pigment, 1.2 to 1.5 parts of anti-settling agent, 0.4 to 0.6 part of defoaming agent, 20 to 22 parts of superfine precipitated barium sulfate, 0.3 to 0.5 part of coupling agent and 8 to 10 parts of deionized water. The water-based anti-corrosion primer has remarkable advantages in the aspects of anti-corrosion performance, adhesive force, stability, drying speed and the like, can be effectively applied to anti-corrosion coating of metal substrates, and provides a product solution with excellent performance for the coating industry.

Description

Technical Field

[0001] The present application relates to the technical field of coating water-based anti-corrosion primers, and in particular to a water-based anti-corrosion primer and a preparation method thereof. Background Art

[0002] Currently, most of the anti-corrosion primers on the market are solvent-based, which release a large amount of volatile organic compounds (VOCs) during use, causing serious impacts on the environment and human health. With increasingly stringent environmental regulations, water-based coatings have received widespread attention due to their low VOCs emission characteristics.

[0003] Although existing water-based anti-corrosion primers have reduced VOCs emissions to a certain extent, due to their formulation and process limitations, they often have problems such as slow drying, poor adhesion, and insufficient corrosion resistance, making it difficult to meet the application needs of the high-end market. Summary of the invention

[0004] The purpose of this application is to provide a water-based anti-corrosion primer and a preparation method thereof in view of the deficiencies in current technology. The water-based anti-corrosion primer prepared in this application has excellent adhesion, salt spray resistance, impact resistance and fast drying of the paint layer.

[0005] In the first aspect, the present application provides a water-based anticorrosive primer, which adopts the following technical solution: A water-based anticorrosive primer comprises the following raw materials, measured by weight: 45-50 parts of water-based epoxy resin emulsion, 15-18 parts of curing agent, 0.2-0.5 parts of wetting agent, 8-12 parts of surface calcium ion modified antirust pigment, 1.2-1.5 parts of anti-settling agent, 0.4-0.6 parts of defoaming agent, 20-22 parts of ultrafine precipitated barium sulfate, 0.3-0.5 parts of coupling agent and 8-10 parts of deionized water.

[0006] By adopting the above technical scheme, water-based epoxy resin emulsion: as the main film-forming substance of the paint film, it has excellent adhesion and corrosion resistance. Curing agent: reacts with water-based epoxy resin emulsion to form a hard cross-linked structure of the paint film, improving the hardness and corrosion resistance of the paint film. Wetting agent: reduces the surface tension between the paint and the substrate, which helps to improve the adhesion of the coating. Surface calcium ionized modified anti-rust pigment: provides excellent anti-corrosion performance, forms a dense protective film, and effectively protects the metal substrate. Anti-precipitation agent: prevents the precipitation of anti-rust pigment and maintains the stability of water-based anti-corrosion primer. Defoaming agent: reduces bubbles on the surface of the paint and ensures smooth coating of the paint. Ultrafine precipitated barium sulfate: as a filler, it also has the function of increasing the hardness and corrosion resistance of the paint film. Coupling agent: can improve the compatibility between different components and improve the adhesion and durability of the paint film. Deionized water: as a diluent, adjusts the viscosity and fluidity of the water-based anti-corrosion primer. The synergistic effect of these raw materials makes the water-based anti-corrosion primer have excellent properties, including adhesion, salt spray resistance, impact resistance, etc., which effectively prolongs the service life of the metal surface and improves the drying performance and stability of the coating.

[0007] Preferably, the method for preparing the waterborne epoxy resin emulsion comprises the following steps: S21. Add 296.3 parts of phthalic anhydride, 4000 parts of polyethylene glycol 4000, 216 parts of n-butanol and 240 parts of ethylene glycol butyl ether into a reactor according to their mass fractions, stir for 5-10 minutes, add 21.5 parts of tetrabutylammonium bromide as a reaction catalyst, pass nitrogen, adjust the stirrer speed to 50-60 rpm, raise the temperature to 105-110° C., maintain condensation reflux reaction for 4-5 hours, and synthesize a prepolymer; S22, according to the mass fractions, add 8000-9000 parts of epoxy resin E-51 and 35-38 parts of triphenylphosphine to the prepolymer, continue to protect under nitrogen, adjust the stirrer speed to 50-60rpm, raise the temperature to 95-98°C, maintain condensation reflux reaction for 4-5h, that is, synthesize epoxy emulsifier; S23. Weigh 100 parts of epoxy resin E-51 in a container according to the mass fraction, add 30 parts of ethylene glycol butyl ether to dissolve it, then add 20 parts of epoxy emulsifier, slowly heat the system to 70°C-80°C, gradually add 120 parts of deionized water under the shearing action of a high-speed disperser until the phase is reversed, stir at a high speed for 10-15 minutes, and cool to room temperature to obtain a water-based epoxy resin emulsion.

[0008] By adopting the above technical scheme, the prepared waterborne epoxy resin emulsion plays a vital role in waterborne anticorrosive primer. The waterborne epoxy resin emulsion plays a major film-forming role in the coating, forming a coating covering the surface of the substrate, providing good adhesion and protection. The waterborne epoxy resin emulsion can form a solid paint film, provide good corrosion resistance, and effectively protect the metal substrate from external corrosives. It is environmentally friendly. Because it is a water-based system, it is conducive to reducing harmful gas emissions and environmental pollution. Synergistic effect with other raw materials: combined with a curing agent, a cross-linked structure can be formed to improve the hardness and durability of the paint film; interact with anti-rust pigments to enhance anticorrosion performance; and work together with wetting agents and coupling agents to improve adhesion and the quality of the coating. The waterborne epoxy resin emulsion can adjust the viscosity, rheology and drying speed of the coating, thereby optimizing the coating performance and use experience of the coating. The waterborne epoxy resin emulsion can improve the hardness, wear resistance and impact resistance of the coating film and extend the service life of the coating. In short, as one of the main components of water-based anti-corrosion primers, water-based epoxy resin emulsion not only has excellent properties, but also can work synergistically with other raw materials to achieve the best effect of the coating.

[0009] Preferably, the method for preparing the surface calcium ion modified rust-proof pigment comprises the following steps: S31, dispersing 10 parts of anti-rust pigment in a mixture of 25 parts of ethanol and 5 parts of deionized water according to the mass fraction, then adding 0.2 parts of 3-aminopropyltriethoxysilane, heating to 35° C. and stirring for 12-15 hours, filtering, washing, and vacuum drying for 10 hours to obtain a silane-modified anti-rust pigment; S32, dispersing 10 parts of silane-modified anti-rust pigment in 25 parts of dichloromethane solution according to mass fractions, adding 3 parts of polyacrylic acid bromide, then heating to 30°C, stirring for 10-12 hours, centrifuging, washing, and vacuum drying for 10-12 hours to obtain an anti-rust pigment with COOH coated on the surface; S33. Disperse 10 parts of surface-coated COOH anti-rust pigment in 30 parts of deionized water according to mass fractions, add 1 part of CaCl2, stir for 12-14 hours, centrifuge, wash, and vacuum dry for 10-12 hours to obtain surface calcium ionized modified anti-rust pigment.

[0010] By adopting the above technical scheme, the surface calcium ion modified anti-rust pigment prepared plays an important role in water-based anti-corrosion primer and synergizes with other raw materials to exert its effect: Surface modification effect: Through silane modification, surface coating COOH and calcium ion modification treatment, the surface of the anti-rust pigment has different functional groups, which increases the interaction with other raw materials and improves the adsorption and adhesion to the metal substrate. Protecting the substrate: The functional groups on the surface of the surface calcium ion modified anti-rust pigment, such as COOH, can interact with the metal surface through chemical bonds to form a dense passivation film, provide good anti-corrosion protection, and bond more firmly with the substrate. Synergistic effect: It interacts with other raw materials in the water-based epoxy resin emulsion, such as wetting agents, curing agents, etc., to jointly improve the adhesion, salt spray resistance and sealing of the coating, thereby improving the overall anti-corrosion effect. Improve stability: After the surface calcium ion modified anti-rust pigment is modified, it can be better dispersed and stabilized in the formula, avoid precipitation and agglomeration, and improve the consistency and coating of the coating. Improve coating performance: By modifying the surface calcium ionization, the anti-rust pigment can better bond with the substrate, improve the wear resistance and impact resistance of the coating, and extend the service life of the coating. In general, surface calcium ionized modified anti-rust pigments play a key role in water-based anti-corrosion primers. Through surface modification and synergy with other raw materials, they can improve the anti-corrosion performance of the coating and the overall performance of the coating, and provide reliable protection for the coating.

[0011] Preferably, the anti-rust pigment is prepared by mixing zinc powder with a particle size of 800 mesh, aluminum zinc phosphomolybdate and basic zinc molybdenum phosphate in a mass ratio of 1:5:8.

[0012] By adopting the above technical scheme, zinc powder: as a traditional anti-rust component, it can provide cathodic protection effect, reduce the corrosion rate of metal, and reduce the occurrence of oxidation and corrosion. Aluminum zinc phosphomolybdate: contains phosphate ions and molybdate ions, which can be adsorbed on the metal surface to form a dense passivation film and an oxide film with repair function, providing good anti-corrosion protection. Basic zinc molybdenum phosphate: has strong anti-corrosion properties, and by forming dense phosphates, it reduces the redox potential, prevents oxidation and the release of metal ions, thereby improving the corrosion resistance of the metal surface. Synergistic effect: these three components work together, such as phosphate ions and molybdate ions can jointly form an effective protective film on the metal surface, repair and inhibit corrosion, and improve anti-corrosion performance. Zinc powder forms a synergistic effect with aluminum zinc phosphomolybdate and basic zinc molybdenum phosphate, which improves the protective performance of the coating on the metal substrate. In the water-based anti-corrosion primer, the combination and ratio of these anti-rust pigments enable the coating to provide excellent anti-corrosion protection, enhance adhesion, salt spray resistance and impact resistance through their respective effects and mutual synergy, and provide comprehensive protection for the metal substrate. At the same time, the combination of these anti-rust pigments also interacts with other ingredients such as water-based epoxy resin emulsion, curing agent, etc. to jointly promote the improvement of the performance of water-based anti-corrosion primer.

[0013] Preferably, the anti-settling agent is prepared by mixing fumed silica and polyamide wax in a mass ratio of 3:1.

[0014] By adopting the above technical scheme, fumed silica: as an auxiliary filler, can effectively inhibit the sedimentation of anti-rust pigments in water-based anti-corrosion primers, improve the dispersibility and stability of the coating, and enable the anti-rust pigments to be evenly distributed throughout the coating system. Polyamide wax: has good lubrication and thickening properties, can improve the coating performance and rheology of water-based anti-corrosion primers, prevent uneven thickness or blistering of the paint film during coating, and enhance the coating and surface quality of the coating. The synergistic effect of fumed silica and polyamide wax can effectively improve the anti-sedimentation performance of water-based anti-corrosion primers in the coating system. Fumed silica reduces the precipitation of anti-rust pigments by increasing the effectiveness of fillers, while polyamide wax improves the rheology and lubricity of the coating, making the coating easier to apply and maintain uniformity, and also helps to enhance the gloss and wear resistance of the coating film. Therefore, the addition of anti-settling agents helps to disperse and stabilize anti-rust pigments in water-based anti-corrosion primers, improve the coating performance of the coating and the quality of the coating film, thereby comprehensively improving the use effect and anti-corrosion performance of water-based anti-corrosion primers.

[0015] Preferably, the coupling agent is composed of dodecyltrimethoxysilane, 3-aminopropyltriethoxysilane and methyltrimethoxysilane in a mass ratio of 1:5:3.

[0016] By adopting the above technical scheme, dodecyl trimethoxysilane: as a hydrophobic coupling agent, it can enhance the bonding between filler and resin in the coating, improve the water resistance and corrosion resistance of the coating, improve the adhesion of the coating to the metal substrate, and also help to improve the hardness and scratch resistance of the coating. 3-aminopropyl triethoxysilane: has hydrophilic and amine functional groups, can react chemically with functional groups such as carboxyl in the resin, improve the compatibility of the resin with pigments, fillers, etc., and can also improve the rheological properties of the coating, reduce the surface tension during coating, and make the coating easier to apply and evenly distribute. Methyl trimethoxysilane: as a weather-resistant coupling agent, it has good high temperature resistance and weather resistance, can form a tough silicon oxygen network structure in the coating, increase the flexibility and wear resistance of the coating, and also help to improve the UV resistance of the coating and extend the service life of the coating. The mixed use of these three components in the coating system can achieve a comprehensive improvement in many aspects of performance, such as improving the adhesion, corrosion resistance and weather resistance of the coating. The structural differences between dodecyltrimethoxysilane and methyltrimethoxysilane can achieve different effects, while 3-aminopropyltriethoxysilane can promote the reaction and improve the compatibility in the coating formulation, thereby acting together on the physical and chemical properties of the coating to achieve a comprehensive improvement in the coating performance. Therefore, the addition of coupling agents to water-based anticorrosive primers helps to improve the performance and stability of the coating, and can also strengthen the bonding between the coating and the substrate, improving the overall quality of the coating.

[0017] Preferably, the wetting agent is wetting agent SN-4575 from Shanghai Shenzhu Chemical Technology Co., Ltd.

[0018] Preferably, the curing agent is the curing agent BS-725 produced by Bass Synthetic New Materials (Shenzhen) Co., Ltd.

[0019] Preferably, the defoamer is BYK-024 produced by BYK Chemical Company.

[0020] In a second aspect, the present application provides a method for preparing a water-based anticorrosive primer, using the following technical solution: As a general technical concept, the present application also provides a method for preparing the above-mentioned water-based anti-corrosion primer, comprising the following steps: mixing deionized water and an anti-settling agent according to their mass fractions, and dispersing and activating them at high speed; then adding a defoaming agent, a surface calcium ionized modified anti-rust pigment, and ultrafine precipitated barium sulfate in sequence, dispersing or sand-grinding to a suitable fineness at high speed, and then adding a wetting agent, a coupling agent, and a water-based epoxy resin and mixing them evenly; finally, adding a curing agent, and then fully mixing them to obtain a water-based anti-corrosion primer.

[0021] In summary, the beneficial technical effects of this application are: 1. Excellent anti-corrosion performance: By using surface calcium ionized modified anti-rust pigments and the design of anti-rust mechanism, a dense passivation film and oxide film can be formed to effectively prevent corrosion of the metal substrate. This layer-by-layer protection mechanism not only enhances the resistance of the coating to the corrosive environment, but also reduces the corrosion effect of salt spray on the metal substrate, thereby improving the anti-corrosion performance of the water-based anti-corrosion primer.

[0022] 2. Excellent adhesion: Through the application of wetting agents and coupling agents, the surface tension between the coating and the metal substrate can be reduced, the bonding strength between the coating and the substrate can be improved, and the adhesion of the coating can be enhanced. This improvement in adhesion helps ensure that the coating adheres firmly to the surface of the substrate and permanently protects the substrate from external erosion.

[0023] 3. Improved stability: By adding anti-settling agents, the precipitation of anti-rust pigments in the primer is effectively avoided, the stability and uniformity of the water-based anti-corrosion primer are improved, and the consistency of the coating during preparation and use is ensured.

[0024] 4. Quick drying performance: The specific materials and process optimization used in the formula make the water-based anti-corrosion primer have a faster drying speed, improving the production efficiency and construction convenience of the coating. DETAILED DESCRIPTION

[0025] The embodiments of the present application will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present application and should not be considered to limit the scope of the present application. If the specific conditions are not specified in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially. The wetting agent is the wetting agent SN-4575 of Shanghai Shenzhu Chemical Technology Co., Ltd., the curing agent is the curing agent BS-725 of Bath Synthetic New Materials (Shenzhen) Co., Ltd., and the defoamer is the defoamer BYK-024 of BYK Chemical.

[0026] Preparation Example 1 Preparation of waterborne epoxy resin emulsion The preparation method of water-based epoxy resin emulsion comprises the following steps: S21. According to the mass fractions, 296.3 g of phthalic anhydride, 4000 g of polyethylene glycol 4000, 216 g of n-butanol and 240 g of ethylene glycol butyl ether were added into the reactor, stirred for 8 minutes, and then 21.5 g of tetrabutylammonium bromide was added as a reaction catalyst. Nitrogen was introduced, the stirrer speed was adjusted to 55 rpm, the temperature was raised to 110° C., and the condensation reflux reaction was maintained for 4.5 hours to synthesize the prepolymer; S22. According to the mass fractions, 8500g of epoxy resin E-51 and 36g of triphenylphosphine are added to the prepolymer, and the stirring speed is adjusted to 55rpm under nitrogen protection, and the temperature is raised to 97°C. The condensation reflux reaction is maintained for 4.5h to synthesize the epoxy emulsifier. S23. According to the mass fractions, 10kg of epoxy resin E-51 is weighed into a container, 3kg of ethylene glycol butyl ether is added to dissolve it, and then 2kg of epoxy emulsifier is added. The system is slowly heated to 78°C. Under the shearing action of a high-speed disperser, 12kg of deionized water is gradually added until the phase is reversed. The mixture is stirred at a high speed for 13 minutes, and cooled to room temperature to obtain a water-based epoxy resin emulsion.

[0027] The aqueous epoxy resin emulsion prepared above was applied to each embodiment.

[0028] Preparation Example 2 Preparation of surface calcium ion modified anti-rust pigment The preparation method of the surface calcium ion modified rust-proof pigment comprises the following steps: S31. Disperse 10 kg of antirust pigment in a mixed solution consisting of 25 kg of ethanol and 5 kg of deionized water according to mass fractions, then add 0.2 kg of 3-aminopropyltriethoxysilane, heat to 35 ° C. and stir for 13 hours, filter, wash, and vacuum dry for 10 hours to obtain a silane-modified antirust pigment, wherein the antirust pigment is prepared by mixing zinc powder with a particle size of 800 mesh, aluminum zinc phosphomolybdate, and basic zinc molybdenum phosphate in a mass fraction ratio of 1:5:8; S32, according to the mass fraction, disperse 10 kg of silane-modified anti-rust pigment in 25 kg of dichloromethane solution, add 3 kg of polyacrylic acid bromide, then heat to 30° C., stir for 11 h, centrifuge, wash, and vacuum dry for 11 h to obtain an anti-rust pigment with COOH coated on the surface; S33. Disperse 10 kg of anti-rust pigment coated with COOH on the surface in 30 kg of deionized water according to the mass fraction, add 1 kg of CaCl2, stir for 13 h, centrifuge, wash, and vacuum dry for 11 h to obtain a surface calcium ionized modified anti-rust pigment.

[0029] The surface calcium ionized modified antirust pigment prepared as above is applied to various examples.

[0030] Preparation of Comparative Example 1 Preparation of Surface Calcium Ionized Modified Antirust Pigment The same as Preparation Example 2, except that: the anti-rust pigment is aluminum zinc phosphomolybdate with a particle size of .

[0031] Preparation of Comparative Example 2 Preparation of Surface Calcium Ion Modified Antirust Pigment The same as Preparation Example 2, except that the anti-rust pigment is zinc powder with a particle size of 800 meshes.

[0032] Preparation of Comparative Example 3 Preparation of Surface Calcium Ionized Modified Antirust Pigment The same as Preparation Example 2, except that: the anti-rust pigment is basic zinc molybdenum phosphate with a particle size of .

[0033] Example 1 A water-based anticorrosive primer comprises the following raw materials, measured by weight: 4.5 kg of water-based epoxy resin emulsion, 1.5 kg of curing agent BS-725, 0.02 kg of wetting agent SN-4575, 0.8 kg of surface calcium ion modified antirust pigment, 0.12 kg of anti-settling agent, 0.04 kg of defoaming agent BYK-024, 2.0 kg of ultrafine precipitated barium sulfate, 0.03 kg of coupling agent, and 0.8 kg of deionized water. The anti-settling agent is prepared by mixing fumed silica and polyamide wax in a weight ratio of 3:1, and the coupling agent is composed of dodecyltrimethoxysilane, 3-aminopropyltriethoxysilane and methyltrimethoxysilane in a weight ratio of 1:5:3.

[0034] The preparation method of the above-mentioned water-based anticorrosive primer comprises the following steps: Deionized water and anti-settling agent are mixed according to the mass fractions, and activated by high-speed dispersion; then defoamer BYK-024, surface calcium ionization modified anti-rust pigment and ultrafine precipitated barium sulfate are added in sequence, and dispersed or sand-milled to a suitable fineness at high speed, and then wetting agent SN-4575, coupling agent and water-based epoxy resin are added and mixed evenly, and finally curing agent BS-725 is added and mixed evenly to obtain a water-based anticorrosive primer.

[0035] Example 2 A water-based anticorrosive primer comprises the following raw materials, measured by weight: 5.0 kg of water-based epoxy resin emulsion, 1.8 kg of curing agent BS-725, 0.05 kg of wetting agent SN-4575, 1.2 kg of surface calcium ion modified antirust pigment, 0.15 kg of anti-settling agent, 0.06 kg of defoaming agent BYK-024, 2.2 kg of ultrafine precipitated barium sulfate, 0.05 kg of coupling agent, and 1 kg of deionized water. The anti-settling agent is prepared by mixing fumed silica and polyamide wax in a weight ratio of 3:1, and the coupling agent is composed of dodecyltrimethoxysilane, 3-aminopropyltriethoxysilane and methyltrimethoxysilane in a weight ratio of 1:5:3.

[0036] The preparation method of the above-mentioned water-based anticorrosive primer comprises the following steps: Deionized water and anti-settling agent are mixed according to the mass fractions, and activated by high-speed dispersion; then defoamer BYK-024, surface calcium ionization modified anti-rust pigment and ultrafine precipitated barium sulfate are added in sequence, and dispersed or sand-milled to a suitable fineness at high speed, and then wetting agent SN-4575, coupling agent and water-based epoxy resin are added and mixed evenly, and finally curing agent BS-725 is added and mixed evenly to obtain a water-based anticorrosive primer.

[0037] Example 3 A water-based anticorrosive primer comprises the following raw materials, measured by weight: 4.8 kg of water-based epoxy resin emulsion, 1.6 kg of curing agent BS-725, 0.03 kg of wetting agent SN-4575, 1 kg of surface calcium ion modified antirust pigment, 0.13 kg of anti-settling agent, 0.05 kg of defoaming agent BYK-024, 2.1 kg of ultrafine precipitated barium sulfate, 0.04 kg of coupling agent, and 0.9 kg of deionized water, wherein the anti-settling agent is prepared by mixing fumed silica and polyamide wax in a weight ratio of 3:1, and the coupling agent is composed of dodecyltrimethoxysilane, 3-aminopropyltriethoxysilane and methyltrimethoxysilane in a weight ratio of 1:5:3.

[0038] The preparation method of the above-mentioned water-based anticorrosive primer comprises the following steps: Deionized water and anti-settling agent are mixed according to the mass fractions, and activated by high-speed dispersion; then defoamer BYK-024, surface calcium ionization modified anti-rust pigment and ultrafine precipitated barium sulfate are added in sequence, and dispersed or sand-milled to a suitable fineness at high speed, and then wetting agent SN-4575, coupling agent and water-based epoxy resin are added and mixed evenly, and finally curing agent BS-725 is added and mixed evenly to obtain a water-based anticorrosive primer.

[0039] Comparative Example 1 The same as Example 3, except that the surface calcium ion modified antirust pigment is the surface calcium ion modified antirust pigment prepared in Comparative Example 1.

[0040] Comparative Example 2 The same as Example 3, except that the surface calcium ion modified antirust pigment is the surface calcium ion modified antirust pigment prepared in Comparative Example 2.

[0041] Comparative Example 3 The same as Example 3, except that the surface calcium ion modified antirust pigment is the surface calcium ion modified antirust pigment prepared in Comparative Example 3.

[0042] Comparative Example 4 The same as Example 3, except that the coupling agent is dodecyltrimethoxysilane.

[0043] Comparative Example 5 The same as Example 3, except that the coupling agent is 3-aminopropyltriethoxysilane.

[0044] Comparative Example 6 The same as Example 3, except that the coupling agent is methyltrimethoxysilane.

[0045] Performance Testing The water-based anticorrosive primers prepared in Examples 1 to 3 and Comparative Examples 1 to 6 were sampled, and a 5 cm x 5 cm x 0.2 cm iron plate was dip-coated with the corresponding water-based anticorrosive primers, and forced dried at low temperature (80°C / 30 min). After standing for 3 days, the following performance tests were performed. The test results are shown in Table 1; Surface drying time: measured according to the provisions of GB / T 1728-2020; Adhesion: Use the 100-grid method to test adhesion, and use a magnifying glass to observe whether the cut part of the coating is smooth and has not fallen off; Neutral salt spray resistance: measured in accordance with the provisions of GB / T1771-2007; Impact resistance: According to GB / T1732-2007, the weight height is 50cm, whether it is positive impact or negative impact, observe whether the coating is damaged; Table 1 Performance test project Adhesion Neutral salt spray resistance / h Impact resistance / 50cm Surface drying time / min Example 1 Level 0 965 No damage 18 Example 2 Level 0 987 No damage 20 Example 3 Level 0 975 No damage 18 Comparative Example 1 Level 0 805 No damage 19 Comparative Example 2 Level 0 847 No damage 18 Comparative Example 3 Level 0 817 No damage 20 Comparative Example 4 Level 1 895 No damage 23 Comparative Example 5 Level 1 884 No damage 24 Comparative Example 6 Level 1 891 No damage 23 Analyzing the data in Table 1, we can see that: 1) The water-based anticorrosive primers prepared in Examples 1 to 3 have excellent adhesion, salt spray resistance, impact resistance and fast drying of the paint layer.

[0046] 2) The performance comparison analysis of the water-based anticorrosive primer prepared in combination with Example 3 and Comparative Examples 1-3 shows that the anti-rust pigment is prepared by mixing zinc powder with a particle size of 800 mesh, aluminum zinc phosphomolybdate and basic zinc molybdenum phosphate in a mass fraction ratio of 1:5:8, and the synergistic effect between them is utilized, such as phosphate ions and molybdate ions can form an effective protective film on the metal surface together, repair and inhibit corrosion, and improve anti-corrosion performance. Zinc powder forms a synergistic effect with aluminum zinc phosphomolybdate and basic zinc molybdenum phosphate, which improves the protective performance of the coating to the metal substrate. In the water-based anti-corrosion primer, the combination and proportion of these anti-rust pigments enable the coating to provide excellent anti-corrosion protection, enhance adhesion, salt spray resistance and impact resistance through their respective effects and mutual synergy, and provide comprehensive protection for the metal substrate. At the same time, through silane modification, surface coating COOH and calcium ionization modification, the surface of the anti-rust pigment has different functional groups, which increases the interaction with other raw materials and improves the adsorption and adhesion to the metal substrate. Protecting the substrate: The functional groups on the surface of the surface calcium ion modified anti-rust pigment, such as COOH, can react with the metal surface through chemical bonds to form a dense passivation film, provide good anti-corrosion protection, and bond more firmly with the substrate. Improving stability: After the surface calcium ion modified anti-rust pigment is modified, it can be better dispersed and stabilized in the formula, avoid precipitation and agglomeration, and improve the consistency and coating of the coating. Improving coating performance: By modifying the surface calcium ionization, the anti-rust pigment can better bond with the substrate, improve the wear resistance and impact resistance of the coating, and extend the service life of the coating.

[0047] 3) The performance comparison analysis of the water-based anticorrosive primers prepared in combination with Example 3 and Comparative Examples 4-6 shows that the coupling agent is composed of dodecyltrimethoxysilane, 3-aminopropyltriethoxysilane and methyltrimethoxysilane in a mass ratio of 1:5:3. By utilizing the synergistic effect between them, comprehensive improvement of various performances can be achieved, such as improving the adhesion, corrosion resistance and drying speed of the coating. The physical and chemical properties of the coating are acted together to achieve a comprehensive improvement in the coating performance. Therefore, the addition of the coupling agent to the water-based anticorrosive primer helps to improve the performance and stability of the coating, and can also strengthen the bonding between the coating and the substrate, thereby improving the overall quality of the coating.

[0048] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation modes of the present invention can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the scope of protection of the present application.

Claims

1. A water-based anticorrosive primer, characterized in that: The preparation raw materials include the following by weight: 45-50 parts of waterborne epoxy resin emulsion, 15-18 parts of curing agent, 0.2-0.5 parts of wetting agent, 8-12 parts of surface calcium ion modified anti-rust pigment, 1.2-1.5 parts of anti-settling agent, 0.4-0.6 parts of defoaming agent, 20-22 parts of ultrafine precipitated barium sulfate, 0.3-0.5 parts of coupling agent and 8-10 parts of deionized water.

2. A water-based anticorrosive primer according to claim 1, characterized in that: The preparation method of the water-based epoxy resin emulsion comprises the following steps: S21. Add 296.3 parts of phthalic anhydride, 4000 parts of polyethylene glycol 4000, 216 parts of n-butanol and 240 parts of ethylene glycol butyl ether into a reactor according to their mass fractions, stir for 5-10 minutes, add 21.5 parts of tetrabutylammonium bromide as a reaction catalyst, pass nitrogen, adjust the stirrer speed to 50-60 rpm, raise the temperature to 105-110° C., maintain condensation reflux reaction for 4-5 hours, and synthesize a prepolymer; S22, according to the mass fractions, add 8000-9000 parts of epoxy resin E-51 and 35-38 parts of triphenylphosphine to the prepolymer, continue to protect under nitrogen, adjust the stirrer speed to 50-60rpm, raise the temperature to 95-98°C, maintain condensation reflux reaction for 4-5h, that is, synthesize epoxy emulsifier; S23. Weigh 100 parts of epoxy resin E-51 in a container according to the mass fraction, add 30 parts of ethylene glycol butyl ether to dissolve it, then add 20 parts of epoxy emulsifier, slowly heat the system to 70°C-80°C, gradually add 120 parts of deionized water under the shearing action of a high-speed disperser until the phase is reversed, stir at a high speed for 10-15 minutes, and cool to room temperature to obtain a water-based epoxy resin emulsion.

3. A water-based anticorrosive primer according to claim 1, characterized in that: The preparation method of the surface calcium ion modified rust-proof pigment comprises the following steps: S31, dispersing 10 parts of anti-rust pigment in a mixture of 25 parts of ethanol and 5 parts of deionized water according to the mass fraction, then adding 0.2 parts of 3-aminopropyltriethoxysilane, heating to 35° C. and stirring for 12-15 hours, filtering, washing, and vacuum drying for 10 hours to obtain a silane-modified anti-rust pigment; S32, dispersing 10 parts of silane-modified anti-rust pigment in 25 parts of dichloromethane solution according to mass fractions, adding 3 parts of polyacrylic acid bromide, then heating to 30°C, stirring for 10-12 hours, centrifuging, washing, and vacuum drying for 10-12 hours to obtain an anti-rust pigment with COOH coated on the surface; S33. Disperse 10 parts of surface-coated COOH anti-rust pigment in 30 parts of deionized water according to mass fractions, add 1 part of CaCl2, stir for 12-14 hours, centrifuge, wash, and vacuum dry for 10-12 hours to obtain surface calcium ionized modified anti-rust pigment.

4. A water-based anticorrosive primer according to claim 3, characterized in that: The anti-rust pigment is prepared by mixing zinc powder with a particle size of 800 meshes, aluminum zinc phosphomolybdate and basic zinc molybdenum phosphate in a mass ratio of 1:5:

8.

5. A water-based anticorrosive primer according to claim 1, characterized in that: The anti-settling agent is prepared by mixing fumed silica and polyamide wax in a mass ratio of 3:

1.

6. A water-based anticorrosive primer according to claim 1, characterized in that: The coupling agent is composed of dodecyltrimethoxysilane, 3-aminopropyltriethoxysilane and methyltrimethoxysilane in a mass ratio of 1:5:

3.

7. A water-based anticorrosive primer according to claim 1, characterized in that: The wetting agent is the wetting agent SN-4575 produced by Shanghai Shenzhu Chemical Technology Co., Ltd.

8. A water-based anticorrosive primer according to claim 1, characterized in that: The curing agent is the curing agent BS-725 produced by Bass Synthetic New Materials (Shenzhen) Co., Ltd.

9. A water-based anticorrosive primer according to claim 1, characterized in that: The defoamer is BYK-024 from BYK Chemicals.

10. A method for preparing a water-based anticorrosive primer according to any one of claims 1 to 9, characterized in that: The following steps are involved: Deionized water and anti-settling agent are mixed according to the mass proportions, and activated by high-speed dispersion; then defoamer, surface calcium ionized modified anti-rust pigment and ultrafine precipitated barium sulfate are added in sequence, and dispersed or sand-milled to a suitable fineness at high speed; then wetting agent, coupling agent and water-based epoxy resin are added and mixed evenly; finally, curing agent is added and mixed evenly to obtain a water-based anti-corrosion primer.