A rust-proof material having hydrophobicity and easy dispersibility, a paint, and a production method

Abstract

The application provides a rust-proof material with hydrophobicity and dispersibility, a coating and a preparation method, and the preparation method comprises the following steps: S1, adding calcium carbonate powder into a stearic acid modifier solution and stirring and reacting; S2, adding a silane coupling agent and stirring and reacting; and S3, filtering and separating and evaporating to remove the solvent. The material obtained by the application has good hydrophobicity, is uniformly dispersed in the resin without agglomeration, and can significantly improve the rust-proof property, corrosion resistance and adhesion of the coating; the preparation method has mild conditions, is simple and convenient to operate, is low in cost, is environment-friendly, and is easy to scale up.

Description

Technical Field

[0001] This invention relates to the field of materials chemistry, and more specifically, to a rust-preventive material, coating, and preparation method that are hydrophobic and easily dispersible. Background Technology

[0002] Metal corrosion is a significant problem causing enormous economic losses and resource waste worldwide, especially in marine engineering, transportation, energy equipment, and infrastructure, where the demand for long-lasting, environmentally friendly, and high-performance rust-preventive materials is increasingly urgent. Currently, coating corrosion protection remains the most widely used and cost-effective protective method. Among these, rust-inhibiting fillers, as key functional components, directly affect the barrier properties, interfacial compatibility, dispersion stability, and long-term corrosion resistance of the coating.

[0003] Traditional inorganic rust-inhibiting fillers such as red lead and chromates, while possessing excellent rust-preventive effects, are strictly restricted or banned by regulations in many countries due to their heavy metal content, high toxicity, and environmental unfriendliness. In recent years, inorganic mineral fillers, represented by calcium carbonate, have become a research hotspot for green alternative rust-inhibiting fillers due to their wide availability, low price, non-toxicity, and renewability. However, natural or ordinary precipitated calcium carbonate has a surface rich in hydroxyl groups, exhibiting strong hydrophilicity and poor compatibility with hydrophobic organic resin matrices (such as epoxy, acrylic, and polyurethane). In coating systems, it easily aggregates and settles, leading to uneven dispersion, increased film defects, and weakened interfacial bonding, thus significantly reducing coating density, adhesion, and long-term rust prevention capabilities. Furthermore, unmodified calcium carbonate has a wide particle size distribution and high surface energy, making stable dispersion in water-based or solvent-based systems difficult, and exhibiting poor storage stability, severely limiting its practical application in high-end environmentally friendly rust-inhibiting coatings.

[0004] Chinese patent CN119662048A discloses a method for modifying calcium carbonate, a superhydrophobic coating, and its preparation method. Using γ-mercaptopropyltriethoxysilane (KH580) as a modifier, calcium carbonate is modified using a specific method, resulting in modified calcium carbonate with excellent hydrophobicity and a contact angle exceeding 120°. These methods use a single surface modifier (such as stearic acid, titanate, or silane coupling agents) to improve the hydrophobicity or dispersibility of calcium carbonate, but generally suffer from insufficient modification, weak interfacial bonding, and difficulty in achieving both hydrophobic and compatibility properties. While modification with stearic acid alone can improve hydrophobicity, insufficient chemical bonding with the resin limits the improvement in coating adhesion. Using silane coupling agents alone results in low modification coverage due to the limited number of active sites on the calcium carbonate surface and low reaction efficiency, and it is difficult to effectively reduce surface energy to achieve a strong hydrophobic effect.

[0005] Therefore, there is an urgent need to develop a new type of calcium carbonate-based rust inhibitor that combines excellent hydrophobicity, good dispersion stability, strong resin interfacial bonding and environmental friendliness, and to establish a green preparation technology with mild process and controllable cost to meet the urgent needs of the modern environmentally friendly functional coatings industry. Summary of the Invention

[0006] The purpose of this invention is to provide a rust-preventive material, coating, and preparation method with hydrophobicity and easy dispersibility. The obtained material has good hydrophobicity and is uniformly dispersed in resin without agglomeration, which can significantly improve the rust prevention, corrosion resistance and adhesion of the coating. The preparation method is mild, easy to operate, low in cost and environmentally friendly, and easy to scale up production. It is suitable for the field of environmentally friendly rust-preventive coatings and functional coatings.

[0007] To achieve the above objectives, this invention provides a rust-preventive material, coating, and preparation method with hydrophobic and easily dispersible properties. The technical solution of this invention is implemented as follows:

[0008] A method for preparing an environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility includes the following steps:

[0009] S1, Add calcium carbonate powder to a stearic acid modifier solution and stir to react;

[0010] S2, add silane coupling agent and stir to react;

[0011] S3, filtration separation, and evaporation to remove solvent.

[0012] Furthermore, the stearic acid modifier is at least one of stearic acid, sodium stearate, and potassium stearate.

[0013] Furthermore, the silane coupling agent is at least one selected from γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

[0014] Furthermore, the concentration of the stearic acid modifier is 0.01~0.2 mol / L.

[0015] Furthermore, the mass of the silane coupling agent is 5% to 15% of the calcium carbonate.

[0016] Furthermore, in step S1, the reaction temperature is 20℃~60℃, and the stirring reaction time is 10min~60min.

[0017] Furthermore, in step S2, the reaction temperature is 40℃~70℃, and the stirring reaction time is 10min~60min.

[0018] Furthermore, the solvent is ethanol, and the amount used is 10~30mL per gram of calcium carbonate.

[0019] An environmentally friendly rust-preventive material with hydrophobic and easily dispersible properties is prepared by the preparation method described above.

[0020] A rust-preventive coating includes the aforementioned rust-preventive material as a functional filler, the amount of which is added to the total mass of the coating at 5-20 wt%, wherein the coating matrix is ​​any one of waterborne acrylic emulsion, waterborne epoxy ester, waterborne polyurethane, or solvent-free epoxy resin.

[0021] Compared with existing technologies, the rust-preventive material, coating, and preparation method with hydrophobicity and easy dispersibility described in this invention have the following advantages:

[0022] 1. In terms of performance, it exhibits significant hydrophobicity, excellent dispersibility, and enhanced rust prevention. With a water contact angle ≥120°, it effectively blocks moisture penetration; the micro / nano-sized particle size and uniform surface modification completely prevent agglomeration, ensuring stable dispersion and no sedimentation in the resin; stearic acid provides a hydrophobic barrier, and the silane coupling agent constructs Si-OC / Si-O-Ca covalent bonds, significantly improving the coating's corrosion resistance, adhesion, and interfacial bonding strength.

[0023] 2. In terms of process, the conditions are mild, the steps are controllable, and the operation is simple. The entire process is carried out in an ethanol system at 20~70℃, without the need for high temperature, high pressure, or strong acids and bases; the two-step sequential modification has a short reaction time and the parameters are easy to control; the finished product is obtained by filtration and drying, without the need for complex purification or special equipment.

[0024] 3. In terms of economy and environmental protection, the raw materials are green, the cost is low, and the environment is friendly. It uses inexpensive, non-toxic, and renewable calcium carbonate as the base material, and the amount of stearic acid and silane coupling agent used is small, resulting in low residue; it avoids precious metals / toxic additives, the ethanol is recyclable, and the energy consumption is low; there are no harmful by-products in the whole process, which meets the requirements of environmental protection regulations, and it is suitable for both water-based and solvent-based dual systems.

[0025] 4. In terms of application and industrialization, it has strong compatibility, is feasible for large-scale production, and yields significant benefits. It is suitable for various mainstream anti-rust resin matrices such as epoxy, acrylic, and polyurethane; the process is simple, reproducible, and easy to scale up to industrial-grade production; it has the dual value of improving coating performance and promoting the upgrading of green coatings, emphasizing both social and economic benefits. Attached Figure Description

[0026] Figure 1 The image shows the infrared spectrum of the modified calcium carbonate described in this embodiment of the invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are only some, not all, of the embodiments of this invention. The specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0028] This invention provides an environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility, and its preparation method, addressing the problems of traditional calcium carbonate rust-preventive materials, such as uneven particle size, strong hydrophilicity, easy agglomeration, poor dispersibility in coatings, and unstable rust-preventive performance. This invention uses inexpensive, non-toxic, and readily available calcium carbonate as the base material and employs a two-step synergistic surface modification strategy of "stearic acid modifier + silane coupling agent." The preparation steps are as follows:

[0029] S1, Add calcium carbonate powder to a stearic acid modifier solution and stir to react. This step is for hydrophobic modification.

[0030] The stearic acid modifier is at least one of stearic acid, sodium stearate, and potassium stearate. The concentration of the stearic acid modifier is 0.01~0.2 mol / L.

[0031] Calcium carbonate can be any one of light calcium carbonate, heavy calcium carbonate, or biological calcium carbonate.

[0032] The reaction temperature is 20℃~60℃, the stirring reaction time is 10min~60min, and the stirring speed is 300~800rpm.

[0033] The solvent is ethanol, and the amount used is 10~30mL per gram of calcium carbonate.

[0034] Calcium carbonate surface is rich in active Ca 2+ Site. In ethanol solvent, stearic acid modifiers (taking sodium stearate as an example) dissociate to release stearate anions, which then interact with Ca through coordinate / ionic bonds. 2+ An in-situ complexation reaction occurs. This reaction can proceed efficiently under mild conditions of 20℃ to 60℃, generating a water-insoluble calcium stearate coating. The generated calcium stearate coating significantly reduces the surface hydroxyl density and polarity, inhibiting the disordered hydrolysis and self-polymerization of silanes on the CaCO3 surface. A concentration of 0.01~0.2 mol / L ensures sufficient anion flux to cover the calcium carbonate; too low a concentration results in incomplete coating, while too high a concentration easily leads to the formation of free micelles, resulting in waste.

[0035] When using weakly acidic stearic acid, it is partially protonated in ethanol medium, via Ca... 2+ -OH -Proton transfer induced by the interfacial microenvironment leads to solid-liquid interfacial reactions; the generation of CO2 bubbles can disturb the particle interface, promoting the exposure of new surfaces and improving the uniformity of modification. Ethanol solvent ensures proper dissociation of stearate while avoiding water-induced CaCO3 dissolution side reactions. A dosage of 10–30 mL / g ensures sufficient particle wetting (capillary penetration) and prevents solvent residue from interfering with subsequent silane grafting.

[0036] Step S1 is a crucial prerequisite for constructing a hydrophobic substrate. If this step is skipped, the silane coupling agent will hydrolyze unevenly due to the strong hydrophilicity of calcium carbonate, resulting in ineffective coupling.

[0037] S2, add silane coupling agent and stir to react. This step is for compatibility enhancement modification.

[0038] The organic ends of silanes can covalently crosslink or strongly polarly interact with coating resins (such as acrylates, epoxy, and polyurethane), improving coating adhesion and salt spray resistance. At the same time, the silane layer further reduces surface energy and introduces steric hindrance; it also works synergistically with the stearic acid layer to compress the thickness of the electrical double layer, forming stable dispersion.

[0039] The silane coupling agent is at least one of γ-aminopropyltriethoxysilane (KH550), γ-glycidoxypropyltrimethoxysilane (KH560), and γ-mercaptopropyltrimethoxysilane (KH580).

[0040] The mass of the silane coupling agent is 5% to 15% of that of calcium carbonate. If it is too low, the grafting will be insufficient, and the improvement in adhesion will be limited; if it is too high, it will easily self-aggregate into a gel, which will reduce the dispersibility.

[0041] The reaction temperature is 40℃~70℃ to ensure complete hydrolysis of silane while preventing thermal decomposition of the stearic acid layer. The stirring reaction time is 10min~60min to achieve the optimal time window.

[0042] S3, filtration separation, and evaporation to remove solvent.

[0043] After filtration and separation, the material is placed in an oven at 60°C until completely dry, resulting in a low-cost modified environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility.

[0044] The rust-preventive material prepared by the above method was characterized by infrared spectroscopy, which confirmed that the stearic acid alkyl chain was successfully grafted and the silane coupling agent was effectively bonded.

[0045] The present invention also provides a rust-preventive coating, wherein the above-mentioned rust-preventive material is used as a functional filler, and its addition amount in the total mass of the coating is 5~20wt%. The coating matrix is ​​any one of water-based acrylic emulsion, water-based epoxy ester, water-based polyurethane or solvent-free epoxy resin.

[0046] The coating, after being applied and cured, forms a dry film with a thickness of 30~80μm. It exhibits no red rust after more than 1000 hours of salt spray testing, has an adhesion level of 0 according to GB / T9286-1998 standard, and a water contact angle of ≥120° on the coating surface.

[0047] Comparative Example 1

[0048] Unmodified calcium carbonate powder.

[0049] Comparative Example 2

[0050] Take 10g of calcium carbonate powder and 1g of KH560 coupling agent and place them in a 200ml three-necked flask. Add 100ml of anhydrous ethanol and stir for 10min. After the reaction is complete, filter, wash and separate the product. Place it in an oven at 60℃ until it is completely dry to obtain the material.

[0051] Example 1

[0052] 10g of calcium carbonate powder was placed in a 200ml three-necked flask. The temperature of the magnetic stirrer was adjusted to 30℃. Under stirring conditions, 100ml of 0.1mol / L stearic acid solution was slowly added dropwise. The mixture was stirred in the magnetic stirrer for 10min. Then, 1g of KH560 coupling agent was added and the mixture was stirred for another 10min. After the reaction was completed, the mixture was filtered, washed and separated. It was then placed in a 60℃ oven until completely dry to obtain a low-cost modified environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility.

[0053] The structures of Comparative Example 1 (which underwent only stearic acid hydrophobic modification) and the modified calcium carbonate prepared in Example 1 were characterized using Fourier transform spectroscopy. The results are as follows: Figure 1 As shown, these correspond to three sets of data, A, B, and C, respectively. In Example 1 (Data C), 1139cm -1 This is an antisymmetric stretching peak for carbonate, 873–917 cm⁻¹. -1 The peak represents the stretching vibration of carbonate ions, 710–760 cm⁻¹. -1 The peaks represent the in-plane and out-of-plane bending vibrations of the carbonate group. These peaks were retained after modification, indicating that stearic acid modification did not destroy the calcium carbonate crystal structure; 2850~2930 cm⁻¹ -1 The absorption enhancement is located near the -CH2- stretching vibration peak, 1450~1470 cm⁻¹. -1 These are shear vibration stretching peaks of CH2, which are the main characteristic peaks of stearic acid, indicating that stearic acid is linked to the calcium carbonate surface. After adding KH560, the peak value is 1078 cm⁻¹. -1 The appearance of the Si-OC / Si-O-Ca vibrational stretching peak indicates that KH560 has been successfully grafted onto the surface of stearic acid-modified calcium carbonate.

[0054] Example 2

[0055] 10g of calcium carbonate powder was placed in a 200ml three-necked flask. The temperature of the magnetic stirrer was adjusted to 30℃. Under stirring conditions, 100ml of 0.1mol / L sodium stearate solution was slowly added dropwise. The mixture was stirred in the magnetic stirrer for 10min. Then, 1g of KH560 coupling agent was added and the mixture was stirred for another 10min. After the reaction was completed, the mixture was filtered, washed and separated. It was then placed in a 60℃ oven until completely dry to obtain a low-cost modified environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility.

[0056] Example 3

[0057] 10g of calcium carbonate powder was placed in a 200ml three-necked flask. The temperature of the magnetic stirrer was adjusted to 30℃. Under stirring conditions, 100ml of sodium stearate solution with a concentration of 0.2mol / L was slowly added dropwise. The mixture was stirred in the magnetic stirrer for 10min. Then, 1g of KH560 coupling agent was added and the mixture was stirred for another 10min. After the reaction was completed, the mixture was filtered, washed and separated. It was then placed in a 60℃ oven until completely dry to obtain a low-cost modified environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility.

[0058] Example 4

[0059] 10g of calcium carbonate powder was placed in a 200ml three-necked flask. The temperature of the magnetic stirrer was adjusted to 30℃. Under stirring, 100ml of 0.2mol / L sodium stearate solution was slowly added dropwise. The mixture was stirred in the magnetic stirrer for 30min. Then, 1g of KH560 coupling agent was added and the mixture was stirred for another 10min. After the reaction was completed, the mixture was filtered, washed and separated. It was then placed in a 60℃ oven until completely dry to obtain a low-cost modified environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility.

[0060] Example 5

[0061] 10g of calcium carbonate powder was placed in a 200ml three-necked flask. The temperature of the magnetic stirrer was adjusted to 50℃. Under stirring, 100ml of 0.2mol / L sodium stearate solution was slowly added dropwise. The mixture was stirred in the magnetic stirrer for 30min. Then, 1g of KH560 coupling agent was added and the mixture was stirred for another 10min. After the reaction was completed, the mixture was filtered, washed and separated. It was then placed in a 60℃ oven until completely dry to obtain a low-cost modified environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility.

[0062] Example 6

[0063] 10g of calcium carbonate powder was placed in a 200ml three-necked flask. The temperature of the magnetic stirrer was adjusted to 50℃. Under stirring, 100ml of 0.2mol / L sodium stearate solution was slowly added dropwise. The mixture was stirred in the magnetic stirrer for 30min. Then, 1g of KH580 coupling agent was added and the mixture was stirred for another 10min. After the reaction was completed, the mixture was filtered, washed and separated. It was then placed in a 60℃ oven until completely dry to obtain a low-cost modified environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility.

[0064] Example 7

[0065] 10g of calcium carbonate powder was placed in a 200ml three-necked flask. The temperature of the magnetic stirrer was adjusted to 50℃. Under stirring conditions, 100ml of 0.2mol / L sodium stearate solution was slowly added dropwise. The mixture was reacted in the magnetic stirrer for 30min. Then, 2g of KH580 coupling agent was added and the mixture was stirred for another 10min. After the reaction was completed, the mixture was filtered, washed and separated. It was then placed in a 60℃ oven until completely dry to obtain a low-cost modified environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility.

[0066] Example 8

[0067] 10g of calcium carbonate powder was placed in a 200ml three-necked flask. The temperature of the magnetic stirrer was adjusted to 50℃. Under stirring conditions, 100ml of 0.2mol / L sodium stearate solution was slowly added dropwise. The mixture was reacted in the magnetic stirrer for 30min. Then, 2g of KH580 coupling agent was added and the mixture was stirred for another 20min. After the reaction was completed, the mixture was filtered, washed and separated. It was then placed in a 60℃ oven until completely dry to obtain a low-cost modified environmentally friendly rust-preventive material with hydrophobicity and easy dispersibility.

[0068] To verify the hydrophobic properties of the modified calcium carbonate of this invention, static water contact angle tests were performed on the samples obtained from Comparative Examples 1 and 2, as well as Examples 1-8. During the test, the samples were pressed into tablets and placed on the sample stage of the contact angle measuring instrument. 5 μL of deionized water was added, and the test was conducted at room temperature. Each sample was measured in triplicate, and the average value was taken. The results are shown in Table 1.

[0069] Table 1 Comparison of water contact angles

[0070] sample Handling method Static water contact angle (°) Comparative Example 1 Unmodified calcium carbonate 24.6±2.1 Comparative Example 2 Calcium carbonate treated with KH560 only 67.8±2.5 Example 1 100 mL of 0.1 mol / L stearic acid, 30 °C, stirred for 10 min; 1 g of KH560, stirred for 10 min. 118.4±1.7 Example 2 100 mL of 0.1 mol / L sodium stearate, 30 °C, stirred for 10 min; 1 g of KH560, stirred for 10 min. 121.6±1.8 Example 3 100 mL of 0.2 mol / L sodium stearate, 30 °C, stirred for 10 min; 1 g of KH560, stirred for 10 min. 126.9±1.6 Example 4 100 mL of 0.2 mol / L sodium stearate, 30 °C, stirred for 30 min; 1 g of KH560, stirred for 10 min. 130.7±1.5 Example 5 100 mL of 0.2 mol / L sodium stearate, 50 °C, stirred for 30 min; 1 g of KH560, stirred for 10 min. 134.2±1.4 Example 6 100 mL of 0.2 mol / L sodium stearate, 50 °C, stirred for 30 min; 1 g of KH580, stirred for 10 min. 132.8±1.6 Example 7 100 mL of 0.2 mol / L sodium stearate, 50 °C, stirred for 30 min; 2 g of KH580, stirred for 10 min. 137.3±1.3 Example 8 100 mL of 0.2 mol / L sodium stearate, 50 °C, stirred for 30 min; 2 g of KH580, stirred for 20 min. 136.1±1.5

[0071] The samples obtained from Comparative Examples 1 and 2, as well as Examples 1-8, were respectively added to a resin / solvent dispersion system for high-speed dispersion, and their particle size distribution was measured using a laser particle size analyzer. Each sample was measured in triplicate, and the average value was taken. The particle size distribution characteristics were characterized by D10, D50, and D90, and the particle size distribution width was characterized by the Span value. The results are shown in Table 2 below.

[0072] Table 2. Particle size distribution test results of different samples

[0073] sample Handling method D10(μm) D50(μm) D90(μm) Span Comparative Example 1 Unmodified calcium carbonate 2.15 8.72 24.86 2.6 Comparative Example 2 Calcium carbonate treated with KH560 only 1.84 6.35 18.72 2.66 Example 1 100 mL of 0.1 mol / L stearic acid, 30 °C, stirred for 10 min; 1 g of KH560, stirred for 10 min. 1.21 4.96 12.87 2.35 Example 2 100 mL of 0.1 mol / L sodium stearate, 30 °C, stirred for 10 min; 1 g of KH560, stirred for 10 min. 1.16 4.58 11.54 2.27 Example 3 100 mL of 0.2 mol / L sodium stearate, 30 °C, stirred for 10 min; 1 g of KH560, stirred for 10 min. 1.03 4.02 9.68 2.15 Example 4 100 mL of 0.2 mol / L sodium stearate, 30 °C, stirred for 30 min; 1 g of KH560, stirred for 10 min. 0.95 3.61 8.36 2.05 Example 5 100 mL of 0.2 mol / L sodium stearate, 50 °C, stirred for 30 min; 1 g of KH560, stirred for 10 min. 0.88 3.24 7.21 1.95 Example 6 100 mL of 0.2 mol / L sodium stearate, 50 °C, stirred for 30 min; 1 g of KH580, stirred for 10 min. 0.91 3.38 7.56 1.97 Example 7 100 mL of 0.2 mol / L sodium stearate, 50 °C, stirred for 30 min; 2 g of KH580, stirred for 10 min. 0.82 2.96 6.41 1.89 Example 8 100 mL of 0.2 mol / L sodium stearate, 50 °C, stirred for 30 min; 2 g of KH580, stirred for 20 min. 0.84 3.05 6.58 1.88

[0074] Unmodified calcium carbonate in the resin dispersion system had a D50 of 8.72 μm, a D90 of 24.86 μm, and a Span value of 2.60, indicating a wide particle size distribution and significant agglomeration. Treatment with KH560 alone reduced the particle size, but the Span value remained high, suggesting that the coupling agent alone had limited effect on improving particle agglomeration. In contrast, samples modified with a combination of stearic acid modifiers and silane coupling agents showed significantly reduced D50 and D90, with the Span value generally falling below 2.35. In particular, Examples 7 and 8 showed D50 decreasing to 2.96 μm and 3.05 μm, respectively, D90 decreasing to 6.41 μm and 6.58 μm, respectively, and Span values ​​decreasing to 1.89 and 1.88, respectively. This indicates that the modified particles significantly reduced agglomeration in the resin system, resulting in a more concentrated particle size distribution and significantly improved dispersion uniformity.

[0075] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for preparing a rust-preventive material with hydrophobicity and easy dispersibility, characterized in that, Includes the following steps: S1, Add calcium carbonate powder to a stearic acid modifier solution and stir to react; S2, add silane coupling agent and stir to react; S3, filtration separation, and evaporation to remove solvent.

2. The preparation method according to claim 1, characterized in that, The stearic acid modifier is at least one of stearic acid, sodium stearate, and potassium stearate.

3. The preparation method according to claim 1, characterized in that, The silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

4. The preparation method according to claim 1, characterized in that, The concentration of the stearic acid modifier is 0.01~0.2 mol / L.

5. The preparation method according to claim 1, characterized in that, The mass of the silane coupling agent is 5% to 15% of calcium carbonate.

6. The preparation method according to claim 1, characterized in that, In step S1, the reaction temperature is 20℃~60℃, and the stirring reaction time is 10min~60min.

7. The preparation method according to claim 1, characterized in that, In step S2, the reaction temperature is 40℃~70℃, and the stirring reaction time is 10min~60min.

8. The preparation method according to claim 1, characterized in that, The solvent is ethanol, and the amount used is 10~30mL per gram of calcium carbonate.

9. A rust-preventive material with hydrophobic and easily dispersible properties, characterized in that, The material is prepared by the preparation method described in any one of claims 1 to 8.

10. A rust-preventive coating, characterized in that, The coating includes the rust-preventive material as described in claim 9 as a functional filler, with an addition amount of 5-20 wt% in the total mass of the coating, and the coating matrix is ​​any one of water-based acrylic emulsion, water-based epoxy ester, water-based polyurethane, or solvent-free epoxy resin.

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