A water-based organic-inorganic hybrid zinc-rich coating and its preparation method

Abstract

This invention belongs to the field of coating technology and discloses a water-based organic-inorganic hybrid zinc-rich coating and its preparation method. The coating components include water-soluble acrylic resin, dispersant, substrate wetting agent, defoamer, co-solvent, anti-settling agent, zinc powder, water-based inorganic resin, and aminosilane coupling agent. The coating prepared by this invention utilizes organic-inorganic hybrid crosslinking, resulting in a denser coating with long-lasting corrosion resistance and durability. Furthermore, it effectively solves the problems of cracking and sagging during application of existing water-based inorganic zinc-rich coatings, as well as the difficulties in zinc powder dispersion and dust pollution during use.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a water-based organic-inorganic hybrid zinc-rich coating and its preparation method. Background Technology

[0002] Water-based inorganic zinc-rich coatings are commonly used heavy-duty anti-corrosion coatings in fields such as containers, bridges, and petrochemicals. They exhibit excellent salt spray resistance and are typically used as anti-corrosion primers. However, water-based inorganic zinc-rich coatings have two main drawbacks in practical application: Firstly, as an inorganic coating, they require precise application. The substrate must be sandblasted, and the thickness of a single coat cannot be too high (dry film thickness ≤ 70μm). Unclean substrates, incomplete sandblasting, or excessively thick coats can lead to coating cracking and sagging. Secondly, most water-based inorganic zinc-rich coatings on the market are currently packaged as two components, with the zinc powder (a mixture of zinc powder and other rust-inhibiting pigments) packaged separately in powder form. When adding the zinc powder to the water-based inorganic emulsion, thorough mechanical stirring is necessary, leading to dust pollution at the application site. Insufficient stirring can cause zinc powder particles to clump, significantly affecting the coating's appearance and anti-corrosion performance.

[0003] Currently, there are several existing technologies to address the cracking problem during the application of water-based inorganic zinc-rich coatings. For example, Chinese patent CN 114574014A uses a modified silicone resin emulsion and a composite anti-settling system and zinc powder corrosion inhibition method to solve the cracking problem during coating application. Because water-based inorganic lithium (potassium) silicate resin has a high alkalinity (pH≥11), ordinary water-based emulsions (silicone emulsions, silicone-acrylic emulsions, etc.) are usually unstable under strong alkalinity, resulting in problems such as colloid formation and precipitation, which is detrimental to the storage of the resin components in the coating. Moreover, silicone emulsions and silicone-acrylic emulsions do not participate in the cross-linking of the coating; they are essentially physical modifications of the water-based inorganic lithium (potassium) silicate resin, resulting in weak coating density and even reducing the coating's salt spray resistance. Chinese patent CN 115785708A uses a technology of adding conductive modified potassium titanate whiskers to the zinc powder component to solve the cracking problem of water-based inorganic zinc-rich coatings. However, these technologies all involve packaging zinc powder individually in powder form, which does not fundamentally solve the problems of difficulty in dispersion and dust pollution during construction. Furthermore, zinc powder is a potentially explosive chemical with flammability, posing a fire or explosion hazard. Special protective measures must be taken for the transportation, storage, and use of zinc powder in powder form. Therefore, adopting new coating technologies to improve the workability of water-based inorganic zinc-rich coatings and solve the problems of cracking, sagging, difficulty in zinc powder dispersion, and dust pollution during application has become an urgent priority. Summary of the Invention

[0004] This invention provides a water-based organic-inorganic hybrid zinc-rich coating and its preparation method, aiming to solve the problems of easy cracking, sagging, and difficulty in zinc powder dispersion and dust pollution caused by existing water-based inorganic zinc-rich coatings during construction and use.

[0005] The technical solution for which this invention seeks protection is as follows:

[0006] A water-based organic-inorganic hybrid zinc-rich coating, characterized in that: the coating is composed of three components, A, B, and C; by weight, the coating comprises the following components: Component A comprises 4-6 parts of water-soluble acrylic resin, 1.0-3.0 parts of dispersant, 0.2-0.5 parts of substrate wetting agent, 0.1-0.2 parts of defoamer, 8-12 parts of cosolvent, 2.0-3.0 parts of anti-settling agent, and 70-80 parts of zinc powder; Component B comprises 20-25 parts of water-based inorganic resin; Component C comprises 3-10 parts of a mixed solution of aminosilane coupling agent and analytical grade ethanol.

[0007] The weight mixing ratio of components A, B and C is 100:(20-25):(3-10), preferably 100:25:5.

[0008] Furthermore, the water-soluble acrylic resin is a water-soluble acrylic resin containing hydroxyl groups, with a hydroxyl content of 1.0%–1.2%, a solids content of 45%–50%, a viscosity of 300–1000 mPa·s, and a pH value of 7–8. The selection of the above parameters will affect the performance of the coating. ① Hydroxyl content: If the hydroxyl value is too low, the degree of cross-linking of the paint film will decrease, resulting in a less dense paint film; if the hydroxyl value is too high, the residual hydroxyl groups that have not participated in the reaction will affect the salt spray resistance and water resistance of the coating. ② pH value: The pH value is selected as neutral because the other raw materials of component A can remain stable in the coating under neutral conditions; otherwise, problems such as layering, precipitation, and gelation will occur. For example, zinc powder is prone to reaction under acidic conditions, and under alkaline conditions, the stability of water-soluble acrylic resin and other additives is poor, resulting in poor stability of component A of the coating. ③ Solids content and viscosity: Solids content and viscosity ensure the overall viscosity stability of the zinc powder component of the coating, and also ensure that the viscosity of the prepared component A is moderate after mixing with components B and C, which is convenient for construction.

[0009] Furthermore, the anti-settling agent is one or a mixture of two of bentonite and fumed silica, preferably in a mass ratio of 1:2.

[0010] Furthermore, the zinc powder is spherical zinc powder with a particle size of 600 mesh to 800 mesh.

[0011] Furthermore, the co-solvent is an alcohol ether solvent, including one or a mixture of several of propylene glycol methyl ether, ethylene glycol butyl ether, and dipropylene glycol methyl ether.

[0012] Furthermore, the aqueous inorganic resin is aqueous potassium silicate resin and / or aqueous lithium silicate resin, with a modulus ≥ 4.9 and pH ≥ 11. The aqueous inorganic resin chosen in this invention is aqueous potassium silicate resin and / or aqueous lithium silicate resin because, based on the film-forming mechanism of this invention, the aqueous potassium silicate resin and / or aqueous lithium silicate resin will crosslink with zinc powder, thereby achieving organic-inorganic hybrid crosslinking. However, other types of aqueous inorganic resins in the prior art do not react with zinc powder and cannot achieve the effects of this invention. Modulus is an important parameter reflecting the crosslinking reaction between aqueous inorganic potassium silicate resin and / or aqueous lithium silicate resin and zinc powder. As the modulus increases, the concentration of active silanol in the solution increases, the silanol dehydration condensation rate accelerates, and the storage stability of the potassium silicate solution decreases. With the increase of modulus, the adhesion of the paint film increases because a higher modulus leads to a higher silanol concentration and a faster curing speed with zinc powder. A low modulus can cause air bubbles to form during the wetting process of zinc powder and easily lead to paint film sagging, as well as poor cross-linking density of the paint film. In this invention, a modulus between 4.9 and 5.5 is more suitable. When the modulus is between 4.9 and 5.5, the pH is ≥11.

[0013] Although silane coupling agents are common reagents in coating preparation, in existing technologies, they are usually used to directly modify organic resins or as adhesion promoters. This invention, however, utilizes silane coupling agents to crosslink with zinc powder. Water-soluble acrylic resin, with the aid of an aminosilane coupling agent and zinc powder as a "bridge," forms a large-molecule spatial network structure with water-based inorganic potassium (lithium) silicate resin, achieving organic-inorganic hybrid crosslinking. The aminosilane coupling agent is one of the important film-forming agents in this invention. In a preferred embodiment, the amino group in the aminosilane coupling agent can be a primary amino group, a secondary amino group, or both, preferably γ-aminopropyltriethoxysilane.

[0014] Analytical grade ethanol is used as the solvent, with a preferred dissolution concentration of 20%. This concentration allows the prepared component C to be more easily and evenly mixed with other components. Since the formulation provided in this invention involves a small amount of aminosilane coupling agent, unlike conventional addition methods, dilution before addition is preferable for ease of weighing and packaging. However, if the concentration is below 20%, it will affect the application viscosity of the coating; a 20% dissolution concentration is therefore more suitable.

[0015] Furthermore, the dispersant is a nonionic dispersant, preferably Zhanxin Company's 6208 / 60 dispersant; the defoamer is a polyether siloxane defoamer, preferably Digo Company's T-810 defoamer; and the substrate wetting agent is an organosilicon twin structure surfactant, preferably Digo Company's T-4100 substrate wetting agent.

[0016] This invention also claims protection for the preparation method of the above-mentioned waterborne organic-inorganic hybrid zinc-rich coating, the specific steps of which are as follows:

[0017] S1. Preparation of zinc powder dispersion slurry components;

[0018] ① Add 4-6 parts of water-soluble acrylic resin to the mixing tank. While stirring at a low speed of 500-800 rpm, add 1.0-3.0 parts of water-based dispersant, 0.2-0.5 parts of substrate wetting agent, 0.1-0.2 parts of water-based defoamer, and 8-12 parts of cosolvent in sequence. After the addition is complete, disperse at a medium speed of 800-1000 rpm for 20-30 minutes.

[0019] ② While the above resin solution is being stirred, add 2.0 to 3.0 parts of anti-settling agent and disperse it at a high speed of 1000 to 1500 rpm for 20 to 30 minutes;

[0020] ③ Add 70-80 parts of zinc powder to the above-mentioned mixing tank and disperse at a high speed of 1000-1500 rpm for 40-50 minutes, requiring a fineness of ≤70μm;

[0021] ④ The above-mentioned well-stirred paint is filtered and packaged to obtain component A of the water-based organic-inorganic hybrid zinc-rich coating;

[0022] S2. The organic-inorganic hybrid zinc-rich coating component B is obtained by treating water-based inorganic potassium silicate resin;

[0023] S3. After treatment with an aminosilane coupling agent, component C of the organic-inorganic hybrid zinc-rich coating is obtained;

[0024] S4. Mix the three components A, B, and C of the water-based organic-inorganic hybrid zinc-rich coating in the specified proportions, stir evenly, apply the coating, and allow it to dry naturally.

[0025] Furthermore, step S2 specifically includes:

[0026] Filter and package 20-25 parts of water-based inorganic potassium silicate and / or water-based inorganic lithium silicate resin to obtain component B of organic-inorganic hybrid zinc-rich coating.

[0027] Furthermore, step S3 specifically includes:

[0028] Dissolve 20 parts of aminosilane coupling agent in 80 parts of analytical grade ethanol, stir until homogeneous, the solution is transparent, weigh 3 to 10 parts, filter and package to obtain component C of organic-inorganic hybrid zinc-rich coating.

[0029] Furthermore, step S4 specifically includes:

[0030] When using, mix the three components A, B, and C of the prepared waterborne organic-inorganic hybrid zinc-rich coating at a weight ratio of 100:(20-25):(3-10). After mixing by hand or mechanical means, apply the coating. The thickness of a single dry film coating can reach 150-200μm. Allow the coating to dry naturally after application.

[0031] Compared with the prior art, the beneficial effects of this invention are:

[0032] 1. The present invention provides a water-based organic-inorganic hybrid zinc-rich coating, wherein a water-based inorganic potassium silicate (lithium) resin is chemically modified using a hydroxyl-containing water-soluble acrylic acid and aminosilane coupling agent.

[0033] This invention differs entirely from existing technologies in its coating reaction mechanism. Traditional methods typically use common aqueous emulsions (such as silicone-acrylic emulsions, styrene-acrylic emulsions, and organosilicon emulsions) to physically modify aqueous inorganic potassium (lithium) silicate resins. However, this invention employs chemical modification, resulting in enhanced density of the coating's molecular structure after drying. Consequently, the coating exhibits significantly improved performance in areas such as salt spray resistance compared to existing technologies.

[0034] 2. This invention differs from existing technologies in that it does not package zinc powder in single-component powder form. Instead, it uses water-soluble acrylic resin, co-solvents, anti-settling agents, and additives to pre-disperse the zinc powder, packaging it as a liquid zinc powder dispersion slurry. During use, it is mixed with other coating components in liquid form. This mixing method has three advantages: ① Using liquid form effectively reduces dust pollution during zinc powder mixing at the construction site, positively impacting the health of construction workers and reducing environmental pollution; ② Pre-preparing the zinc powder into a pre-dispersed slurry makes mixing easier during application, eliminating the need for prolonged mechanical mixing and allowing for easy manual mixing to ensure uniform mixing with other components, facilitating coating operations; ③ Zinc powder is a potentially explosive chemical with flammability, posing a fire or explosion hazard. Transporting, storing, and using zinc powder in powder form requires special protective measures. However, transporting, storing, and using zinc powder in pre-dispersed slurry liquid form significantly reduces the risk of fire and explosion.

[0035] 3. The water-soluble acrylic resin used in this invention exhibits a certain degree of viscosity increase when mixed with water and water-based inorganic potassium (lithium) silicate resin. This is beneficial for improving the anti-sagging properties of the prepared water-based organic-inorganic hybrid zinc-rich coating during application. Currently, the single-coat thickness of existing water-based inorganic zinc-rich coatings is 50–70 μm; otherwise, sagging and cracking of the paint film are easily encountered. However, the water-based organic-inorganic hybrid zinc-rich coating prepared by this invention can achieve a single-coat thickness of 150–200 μm during application without cracking, significantly improving coating efficiency.

[0036] 4. Waterborne inorganic potassium silicate (lithium) resin is strongly alkaline (pH≥11), while waterborne emulsions and other waterborne coating liquid raw materials are generally neutral (pH 7-8). In a strongly alkaline environment, waterborne coating emulsions (including other waterborne liquid raw materials) are difficult to disperse stably in waterborne inorganic potassium silicate (lithium) resin for extended periods, easily leading to problems such as particle formation, demulsification, precipitation, and gelation, which are detrimental to storage. This invention uses a three-component packaging method, effectively avoiding the above problems. The three components of the waterborne organic-inorganic hybrid zinc-rich coating prepared by this invention can be stored independently and stably for a long period. After storage at room temperature for one year and at 50°C for 30 days, no problems of particle formation, demulsification, precipitation, or gelation were observed in any of the three components. After mixing the three components, the usable time is ≥6 hours, fully meeting the requirements for coating application.

[0037] 5. The water-based organic-inorganic hybrid zinc-rich coating prepared by this invention is a water-based coating product. Water is used as a diluent during construction, resulting in minimal harm to human health and the environment. The coating prepared by this invention has long-lasting corrosion resistance and durability, with a designed service life of 10-15 years, fully meeting the long-lasting, economical, and safe corrosion protection requirements of industries such as bridges and petrochemicals. Attached Figure Description

[0038] Figure 1 Reaction mechanism diagram of the present invention

[0039] Figure 2 Test photos of the waterborne organic-inorganic hybrid zinc-rich coating prepared by this invention. Detailed Implementation

[0040] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0041] To facilitate understanding of the invention, certain technical and scientific terms are specifically defined below. Unless otherwise expressly defined elsewhere in this document, all other technical and scientific terms used herein have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains.

[0042] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0043] Table 1 shows the corresponding manufacturers for some of the raw material product numbers involved in this invention:

[0044] Table 1. Raw materials, models, and manufacturers of this invention.

[0045]

[0046]

[0047] To further elaborate on the invention, the appendix is ​​now attached. Figure 1 The reaction mechanism of this invention will be explained as follows:

[0048] ① During the coating drying process, the hydroxyl groups of the water-soluble acrylic resin can react with the amino functional groups of the aminosilane coupling agent; ② The silanol groups (Si-OH) generated after the aminosilane coupling agent is hydrolyzed under alkaline conditions (the water-based inorganic resin is strongly alkaline) react with zinc powder; ③ The Si-OH in the water-based inorganic potassium silicate (lithium) resin undergoes a cross-linking reaction with the zinc powder; ④ With the aminosilane coupling agent and zinc powder as "bridges," the water-soluble acrylic resin forms a large molecular spatial network structure with the water-based inorganic potassium silicate (lithium) resin, achieving organic-inorganic hybrid cross-linking. Therefore, this invention is completely different from the physical modification methods used in the prior art to prepare water-based coatings. Instead, it utilizes hydroxyl-containing water-soluble acrylic acid and aminosilane coupling agents to chemically modify the water-based inorganic potassium silicate (lithium) resin. The following embodiments of this invention are all based on the above reaction mechanism.

[0049] Examples 1-3

[0050] (1) Preparation of zinc powder dispersion slurry components:

[0051] ① Add water-soluble acrylic resin to the mixing tank, and add water-based dispersant, substrate wetting agent, water-based defoamer and cosolvent in sequence while stirring at a low speed of 500-800 rpm. After the addition is completed, disperse at a medium speed of 800-1000 rpm for 20-30 minutes.

[0052] ② While the above resin solution is being stirred, an anti-settling agent is added, and the solution is dispersed at a high speed of 1000-1500 rpm for 20-30 minutes;

[0053] ③ Add zinc powder to the above-mentioned mixing tank and disperse it at a high speed of 1000-1500 rpm for 40-50 minutes, requiring a fineness of ≤70μm;

[0054] ④ The above-mentioned well-stirred paint is filtered and packaged to obtain component A of the water-based organic-inorganic hybrid zinc-rich coating;

[0055] (2) The water-based inorganic potassium silicate resin is filtered (to remove impurities) and packaged to obtain component B of the organic-inorganic hybrid zinc-rich coating;

[0056] (3) Dissolve the aminosilane coupling agent in analytical grade ethanol, stir until homogeneous, and the solution is transparent.

[0057] The organic-inorganic hybrid zinc-rich coating component C was obtained by filtration (removing impurities) and packaging.

[0058] (4) When using, mix the three components A, B and C of the prepared water-based organic-inorganic hybrid zinc-rich coating in proportion. After stirring manually or mechanically, apply the coating. The thickness of a single dry film coating can reach 150-200μm. Allow the coating to dry naturally after application.

[0059] Comparative Examples 1-3

[0060] The operating steps for Comparative Examples 1-3 were the same as those for Example 1, and the raw material ratios are shown in Table 2, resulting in water-based inorganic zinc-rich coatings. Comparative Example 4 used a commercially available water-based inorganic zinc-rich coating (modified with silicone-acrylic emulsion), and the coating film performance test results are shown in Table 3.

[0061] Table 2

[0062]

[0063] Table 3

[0064]

[0065]

[0066] Comparative analysis of results:

[0067] 1. The coating prepared by this invention exhibits superior performance compared to Comparative Examples 1 to 4 in terms of pull-off adhesion, MEK wiping resistance, and salt spray resistance. This indicates that the coating prepared by this invention utilizes a hydroxyl-containing water-soluble acrylic acid and aminosilane coupling agent. After chemically modifying the water-based inorganic potassium silicate resin, the corrosion resistance of the coating is significantly improved. The coating employs organic-inorganic hybrid crosslinking, further increasing the crosslinking density of the prepared film and resulting in a denser coating. Comparative Examples 1-2 showed unsatisfactory pull-off adhesion, MEK wiping resistance, and salt spray resistance, indicating that the water-soluble acrylic resin did not participate in the crosslinking of the coating due to the absence of aminosilane as a "bridge." The performance test results of Comparative Example 3 show that, without the participation of hydroxyl-containing water-soluble acrylic resin in the crosslinking reaction, Comparative Example 3 is not significantly different from Comparative Example 4 (pre-existing technology) in terms of pull-off adhesion, MEK wiping resistance, and salt spray resistance. It has been fully demonstrated that the components of this invention, namely water-soluble acrylic resin, aminosilane, water-based inorganic potassium silicate resin, and zinc powder, produce a synergistic effect after chemical cross-linking, which greatly improves the density, adhesion, and salt spray resistance of the paint film.

[0068] 2. The coating prepared by this invention exhibits superior storage stability compared to Comparative Examples 2-4. Comparative test results show that: ① The coating prepared by this invention demonstrates ideal storage stability for all components, regardless of whether it is stored at room temperature or under a 50°C heat storage environment; ② Due to the strong alkalinity of the water-based inorganic potassium silicate resin, its stability is unsatisfactory when mixed with ordinary water-based organic resin emulsions, easily leading to the formation of particles, precipitation, and gelation.

[0069] Problems include: ③ If zinc powder is not stored properly, it is prone to react with moisture in the air, resulting in clumping.

[0070] 3. The coating prepared by this invention exhibits superior dispersibility compared to Comparative Examples 3 and 4 (existing technologies) after the components are mixed. Comparative test results show that: ① By preparing the zinc powder into a dispersion slurry and mixing the components in liquid form, stirring is easier during use. It eliminates the need for prolonged stirring with mechanical tools; manual stirring easily mixes the zinc powder pre-dispersion slurry with the other components, facilitating coating operations. ② The coating prepared by this invention does not produce zinc powder dust during stirring. Comparative Examples 3 and 4, however, exhibit dust pollution, which may have some impact on the health of operators.

[0071] 4. The coating prepared by this invention is superior to Comparative Examples 3 and 4 (existing technologies) in terms of anti-sagging and anti-cracking properties. The water-soluble acrylic resin used in this invention exhibits a certain degree of viscosity increase after mixing with water (water-based inorganic resin). The coating's anti-sagging properties meet the requirement of a dry film thickness of 150–200 μm without sagging, and the paint film shows no cracking. Comparative Examples 3 and 4 only achieve an anti-sagging property of 70 μm dry film thickness, and slight cracking occurs at the edges of the paint film. This clearly demonstrates that the coating prepared by this invention can significantly improve coating efficiency during application.

[0072] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An aqueous organic-inorganic hybrid zinc-rich coating, characterized in that, The paint contains A, B, C three components; by weight, the paint includes the following components: A component includes water-soluble acrylic resin 4-6 parts, dispersing agent 1.0-3.0 parts, base material wetting agent 0.2-0.5 parts, defoaming agent 0.1-0.2 parts, cosolvent 8-12 parts, anti-settling agent 2.0-3.0 parts, zinc powder 70-80 parts; B component includes water-based inorganic resin 20-25 parts; C component includes amino silane coupling agent and analytical grade ethanol mixed solution 3-10 parts; the weight mixing ratio of the components A, B, C is 100: (20-25): (3-10); the water-soluble acrylic resin is a water-soluble acrylic resin containing hydroxyl, the hydroxyl content is 1.0%-1.2%, the mass solid content is 45%-50%, the viscosity is 300-1000 mPa·s, and the pH value is 7-8; the water-based inorganic resin is water-based potassium silicate resin, the modulus is ≥4.9, and the pH is ≥11.

2. The aqueous organic-inorganic hybrid zinc-rich coating according to claim 1, characterized in that, The amino group in the amino silane coupling agent is primary amino group, secondary amino group or both primary amino group and secondary amino group.

3. The aqueous organic-inorganic hybrid zinc-rich coating of claim 1, wherein, The amino silane coupling agent is gamma-aminopropyl triethoxysilane, and the solvent is analytical grade ethanol with a dissolution concentration of 20%.

4. The aqueous organic-inorganic hybrid zinc-rich coating of claim 1, wherein, The anti-settling agent is one or a mixture of both of bentonite and fumed silica, and the mixing ratio is 1:

2.

5. The aqueous organic-inorganic hybrid zinc-rich coating of claim 1, wherein, The zinc powder is spherical zinc powder, and the particle size of the zinc powder is 600-800 mesh.

6. The aqueous organic-inorganic hybrid zinc-rich coating of claim 1, wherein, The cosolvent is an alcohol ether solvent, including one or a mixture of several of propylene glycol methyl ether, ethylene glycol butyl ether, and dipropylene glycol methyl ether.

7. The aqueous organic-inorganic hybrid zinc-rich coating of claim 1, wherein, The dispersing agent is a non-ionic dispersing agent; the defoaming agent is a polyether siloxane defoaming agent; and the base material wetting agent is an organosilicon twin structure surfactant.

8. The method for preparing the waterborne organic-inorganic hybrid zinc-rich coating according to claim 1, characterized in that, The steps are: S1. Preparing zinc powder dispersion slurry component: ①In a batching tank, add water-soluble acrylic resin, and then add dispersing agent, base material wetting agent, defoaming agent, and cosolvent under low-speed stirring at a speed of 500-800 rpm; after the addition is completed, disperse at a speed of 800-1000 rpm for 20-30 minutes; ②Under stirring, add anti-settling agent to the resin liquid, and disperse at a speed of 1000-1500 rpm for 20-30 minutes; ③Add zinc powder to the above-mentioned batching tank, and disperse at a speed of 1000-1500 rpm for 40-50 minutes, and the fineness is required to be ≤70 μm; ④Filter and package the uniformly stirred paint to obtain water-based organic-inorganic hybrid zinc-rich paint A component; S2. After treating water-based inorganic potassium silicate resin, obtain organic-inorganic hybrid zinc-rich paint B component; S3. After treating amino silane coupling agent, obtain organic-inorganic hybrid zinc-rich paint C component; S4. Mix water-based organic-inorganic hybrid zinc-rich paint A, B, and C components in proportion, stir uniformly, and perform coating construction and natural drying.

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