A moisture-curing epoxy coating for marine conditions

Abstract

The present invention discloses a marine moisture-curing epoxy coating. The marine moisture-curing epoxy coating comprises the following raw materials in parts by weight: 100-140 parts of epoxy resin, 30-50 parts of curing agent, 20-30 parts of rust-proof pigment, 3-8 parts of silane coupling agent, 20-30 parts of filler, 2-4 parts of dispersant, 1-3 parts of leveling agent, 1-3 parts of defoaming agent, and 15-25 parts of functional additives. Compared with the prior art, the marine moisture-curing epoxy coating prepared by the present invention exhibits no "whitening" during moisture curing, strong adhesion, and strong anti-penetration ability. It can provide antibacterial and fireproof protection for the coating, enhance the coating's durability in marine environments, and is suitable for use in marine environments.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, in particular to a moisture-curing epoxy coating under marine conditions. Background Art

[0002] Marine moisture-curing epoxy coatings are coating systems specifically designed for use in marine environments. The marine environment, characterized by high humidity, salinity, and strong UV radiation, places higher demands on coating performance and durability. Moisture-curing epoxy coatings are a common choice, curing under humid conditions to form a durable film.

[0003] Considering the fire safety issues in the marine environment, a wet-curing epoxy coating with good flame retardant properties is developed. Common flame retardants include brominated flame retardants, phosphorus flame retardants, etc., which can effectively inhibit the spread of flames and improve the flame retardant properties of the coating. The high salinity and humid conditions in the marine environment can easily cause metal corrosion. Therefore, a wet-curing epoxy coating with excellent corrosion resistance is developed. Common anti-corrosion strategies include adding corrosion inhibitors, using barrier fillers, etc. to provide an effective protective layer. There are a large number of microorganisms in the marine environment, and their attachment and growth can easily cause damage and corrosion to the coating. Therefore, a wet-curing epoxy coating with anti-biological adhesion properties is developed. Common methods include adding antibacterial agents, surface modification to reduce microbial attachment, etc. In addition to basic protective functions, efforts are also made to give wet-curing epoxy coatings other special functions, such as self-healing properties, self-cleaning properties, etc., to meet specific needs.

[0004] The research and development of moisture-curing epoxy coatings under marine conditions needs to focus on improving flame retardancy, corrosion resistance, anti-biological adhesion and environmental performance, and through continuous innovation and improvement, provide coatings that are more durable and adaptable to the marine environment.

[0005] China's authorized invention patent CN111253834B discloses a moisture-curing epoxy coating and its preparation method. The coating comprises, by weight, 100 parts epoxy resin, 40-80 parts ketimine curing agent, 10-50 parts reactive diluent, 10-30 parts reactive toughening agent, 20-30 parts anti-rust pigment, 20-30 parts mica powder, 4-13 parts silane coupling agent, 0.5-2 parts fumed SiO2, 2-7 parts dispersant, 1-3 parts leveling agent, and 1-3 parts defoaming agent. This invention is primarily used for coating metal substrates in humid environments, exhibiting no "whitening" and a bond strength retention rate exceeding 96% compared to dry conditions. The coating exhibits excellent adhesion, flexibility, and protective properties. However, the mechanical, antibacterial, anticorrosive, and fire-retardant properties of the epoxy coating produced using this invention still require further improvement. Summary of the Invention

[0006] In view of the shortcomings of epoxy coatings in the prior art in terms of poor mechanical properties, antibacterial properties, anticorrosion properties and fire retardancy, the technical problem to be solved by the present invention is to provide a moisture-curing epoxy coating under marine conditions with good mechanical properties, antibacterial properties, anticorrosion properties and fire retardancy.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0008] A moisture-curing epoxy coating under marine conditions, comprising the following raw materials in parts by weight:

[0009] 100-140 parts of epoxy resin, 30-50 parts of curing agent, 20-30 parts of anti-rust pigment, 3-8 parts of silane coupling agent, 20-30 parts of filler, 2-4 parts of dispersant, 1-3 parts of leveling agent, 1-3 parts of defoaming agent, 15-25 parts of functional additives;

[0010] The curing agent is at least one of a ketimine curing agent and an epoxy polyamide curing agent.

[0011] The silane coupling agent is at least one of vinyl triethoxysilane, aniline methyl triethoxysilane, γ-(2,3-epoxypropoxy)propyl trimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyl triethoxysilane.

[0012] The anti-rust pigment is at least one of zinc phosphate, red iron oxide, aluminum tripolyphosphate, zinc oxide, and molybdate.

[0013] The filler is at least one of talc powder, calcium carbonate, magnesium oxide, quartz powder, iron titanium powder, graphite powder and yumen clay.

[0014] The dispersant is at least one of fatty acids and aliphatic amides.

[0015] The leveling agent is a fluorocarbon leveling agent.

[0016] The defoaming agent is a polysiloxane defoaming agent.

[0017] The present invention also provides a method for preparing a moisture-curing epoxy coating under marine conditions.

[0018] A method for preparing a moisture-curing epoxy coating under marine conditions is as follows:

[0019] Step 1, weighing each raw material according to parts by weight, adding epoxy resin, dispersant, leveling agent, and silane coupling agent into a dispersion tank, and dispersing at a speed of 500 to 1500 rpm for 3 to 8 minutes to obtain a mixture;

[0020] Step 2: Add filler and anti-rust pigment to the mixture prepared in step 1, disperse at a speed of 1000-1500 rpm for 10-30 min, then add defoamer and functional additives, and disperse at a speed of 500-1500 rpm for 3-8 min to obtain a dispersion;

[0021] Step 3: Add a curing agent to the dispersion prepared in step 2, and disperse at 50-70° C. and 600 rpm for 2 h to obtain an epoxy coating.

[0022] The preparation method of the functional additive is as follows, in parts by weight:

[0023] S1. Add 30 to 50 parts of 3,4,5-trihydroxybenzaldehyde and 15 to 25 parts of 4,4'-diaminobenzophenone to 180 to 220 parts of N,N-dimethylformamide, stir at 100 to 300 rpm for 20 to 40 minutes under a nitrogen atmosphere at 60 to 80°C, then react for 4 to 8 hours under a nitrogen atmosphere at 60 to 80°C, add 20 to 30 wt% ethanol aqueous solution, filter 3 to 6 times through a 200 to 600 mesh sieve, collect the solid, and dry it in a vacuum at 80 to 100°C for 20 to 50 hours to obtain a powder;

[0024] S2, 10 to 30 parts of the powder prepared in step S1, 80 to 100 parts of methyl epichlorohydrin and 1 to 2 parts of hexadecyltributylammonium bromide were mixed, and the mixture was stirred at 100 to 300 rpm for 4 to 8 hours under a nitrogen atmosphere at 100 to 110° C., and cooled to room temperature. Then, 30 to 40 parts of a 20 to 35 wt % aqueous sodium hydroxide solution were added in an ice-water bath, and the mixture was stirred at 100 to 300 rpm for 4 to 8 hours at 50 to 70° C., and the solvent was removed by rotary evaporation. The mixture was purified with a 20 to 35 wt % aqueous dichloromethane solution, and washed with water 1 to 5 times to obtain an organic layer, and the solvent was removed by rotary evaporation to obtain an oily substance;

[0025] S3. Add 8 to 12 parts of the oil prepared in step S2 and 2 to 3 parts of N-butyldiethanolamine to 40 to 60 parts of anhydrous ethanol, stir at 100 to 300 rpm for 1 to 3 hours to obtain a functional agent, add 0.5 to 2 parts of acetic acid, stir at 100 to 300 rpm for 10 to 30 minutes to obtain a functional additive.

[0026] The functional additive prepared by this invention contains an aromatic Schiff base structure, which can give the cured epoxy coating a more cross-linked structure and a denser carbon layer, thereby enhancing the barrier effect and thermal stability of the epoxy coating during thermal degradation. Flame retardancy is very important for epoxy resins used for metal and wood protection.

[0027] The carbon-nitrogen cross-linked hexacyclic rings formed by the Schiff base structure of the present invention also exhibit flame retardancy in the gas phase, enhancing the smoke suppression properties of epoxy coatings. The functional additive may have a high crosslink density in epoxy resins, and the Schiff base structure facilitates the formation of residual carbon. This reinforced residual carbon acts as a protective layer, preventing further combustion of the material, effectively delaying combustion and reducing the propagation rate of flames.

[0028] Antimicrobial properties and wettability play a key role in the practical application of coatings, reflecting, to a certain extent, the coating's anti-fouling and antimicrobial capabilities. The functional additive prepared by the present invention exhibits antimicrobial and wettability due to its hydrophilic Schiff base structure. This structure inherently absorbs water, and the surface hydrophilic groups gradually form a hydration layer. This gives the epoxy coating a highly hydrophilic surface, while the epoxy coating's high crosslinking density effectively prevents water penetration.

[0029] The hydroxyl groups on the surface of the epoxy coating combine with excess water molecules to form a hydration layer, which prevents the adsorption of bacteria and leads to a reduction in bacteria. In addition to the participation of hydrophilic groups in preventing bacterial colony adhesion, the antibacterial effect of Schiff bases also plays a decisive role. The cell wall of Escherichia coli is thin and loose, and is more susceptible to interference, making it difficult for bacteria to adhere to the surface of the coating for further adsorption and reproduction. This shows that the functional additives prepared by the present invention have excellent antibacterial effects and are suitable for coating on the surfaces of various materials to prevent bacterial attachment. In addition, the fracture surface network of the epoxy coating is tighter and more uniform. The cross-linked structure runs through the interior of the epoxy coating, presenting more wrinkles and entangled structures, giving the epoxy coating better mechanical properties.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1) The moisture-curing epoxy coating prepared under marine conditions by the present invention has great potential in improving the mechanical properties, antibacterial properties, anticorrosive properties and fire retardant properties of the epoxy coating due to the introduction of functional additives. It can provide antibacterial protection for the coating and enhance the durability of the coating in the marine environment, and is suitable for application in the marine environment.

[0032] 2) The use of a fatty acid dispersant and a fluorocarbon leveling agent in step 1 and the dispersion process in step 2 in the moisture-curing epoxy coating under marine conditions prepared by the present invention can uniformly disperse the particles and fillers in the coating, avoid the precipitation of the curing agent and other components, and improve the stability and performance of the coating.

[0033] 3) In the step 3 of the moisture-curing epoxy coating prepared under marine conditions according to the present invention, a ketimine curing agent is used. The curing agent has high reactivity and curing speed, can be cured rapidly at a relatively low temperature, has the characteristics of no "whitening phenomenon" during moisture curing, strong adhesion, and strong anti-penetration ability, thereby improving the production efficiency of the coating. DETAILED DESCRIPTION

[0034] Main sources of substances:

[0035] Epoxy resin: Zhengzhou Penghui Chemical Products Co., Ltd., brand: cydw-100.

[0036] Glyceryl monostearate: Shanghai Liming Chemical Co., Ltd., product number: 45354.

[0037] Fluorocarbon modified polyacrylate leveling agent: Foshan Kening New Materials Co., Ltd., model: KMT-1020.

[0038] Talc powder: Henan Bafusi Chemical Products Co., Ltd., fineness: 325 mesh.

[0039] Polydimethyl polyether siloxane: Dongguan Guozhong New Materials Research Institute Co., Ltd., product number: DU-600.

[0040] Ketimine curing agent: Jining Beinuoke Biotechnology Co., Ltd., product number: AL-613379194736.

[0041] Example 1

[0042] A method for preparing a moisture-curing epoxy coating under marine conditions is as follows:

[0043] Step 1: 120 g of epoxy resin, 3 g of glyceryl monostearate, 2 g of fluorocarbon-modified polyacrylate leveling agent, and 5 g of vinyltriethoxysilane were added to a dispersion tank and dispersed at a speed of 900 rpm for 5 min to obtain a mixture;

[0044] Step 2: Add 25 g of talc and 25 g of zinc phosphate to the mixture prepared in step 1, and disperse at 1200 rpm for 20 min. Then, add 2 g of polydimethyl polyether siloxane and 20 g of functional additives, and disperse at 1000 rpm for 5 min to obtain a dispersion;

[0045] Step 3: Add 40 g of ketimine curing agent to the dispersion prepared in step 2, and disperse at 60° C. and 600 rpm for 2 h to obtain an epoxy coating.

[0046] The preparation method of the functional additive is as follows:

[0047] S1. Add 40 g of 3,4,5-trihydroxybenzaldehyde and 20 g of 4,4'-diaminobenzophenone to 200 g of N,N-dimethylformamide, stir at 200 rpm for 30 min under a nitrogen atmosphere at 70°C, then react for 6 h under a nitrogen atmosphere at 70°C, add 25 wt% aqueous ethanol solution, filter through a 400 mesh sieve 5 times, collect the solid, and dry it in a vacuum at 90°C for 48 h to obtain a powder;

[0048] S2, 20g of the powder prepared in step S1, 92g of methyl epichlorohydrin and 1.8g of hexadecyltributylammonium bromide were mixed, stirred at 200rpm for 6h under a nitrogen atmosphere at 105°C, cooled to room temperature, and then 35g of a 30wt% aqueous sodium hydroxide solution was added in an ice-water bath. After stirring at 200rpm for 6h at 60°C, the solvent was removed by rotary evaporation, and the mixture was purified with a 30wt% aqueous dichloromethane solution and washed with water 5 times to obtain an organic layer. The solvent was removed by rotary evaporation to obtain an oily substance;

[0049] S3. Add 10 g of the oil prepared in step S2 and 2.5 g of N-butyldiethanolamine to 50 g of anhydrous ethanol, stir at 200 rpm for 2 h to obtain a functional agent, add 1 g of acetic acid, stir at 200 rpm for 20 min to obtain a functional additive.

[0050] Comparative Example 1

[0051] The preparation method of a moisture-curing epoxy coating under marine conditions is basically the same as that of Example 1, with the only difference being that the preparation method of the functional additive is different.

[0052] The preparation method of the functional additive is as follows:

[0053] S1. Add 40 g of protocatechuic aldehyde and 20 g of 4,4'-diaminobenzophenone to 200 g of N,N-dimethylformamide, stir at 200 rpm for 30 min under a nitrogen atmosphere at 70°C, then react for 6 h under a nitrogen atmosphere at 70°C, add 25 wt% aqueous ethanol solution, filter through a 400 mesh sieve five times, collect the solid, and dry it in a vacuum at 90°C for 48 h to obtain a powder;

[0054] S2, 20g of the powder prepared in step S1, 92g of methyl epichlorohydrin and 1.8g of hexadecyltributylammonium bromide were mixed, stirred at 200rpm for 6h under a nitrogen atmosphere at 105°C, cooled to room temperature, and then 35g of a 30wt% aqueous sodium hydroxide solution was added in an ice-water bath. After stirring at 200rpm for 6h at 60°C, the solvent was removed by rotary evaporation, and the mixture was purified with a 30wt% aqueous dichloromethane solution and washed with water 5 times to obtain an organic layer. The solvent was removed by rotary evaporation to obtain an oily substance;

[0055] S3. Add 10 g of the oil prepared in step S2 and 2.5 g of N-butyldiethanolamine to 50 g of anhydrous ethanol, stir at 200 rpm for 2 h to obtain a functional agent, add 1 g of acetic acid, stir at 200 rpm for 20 min to obtain a functional additive.

[0056] Comparative Example 2

[0057] The preparation method of a moisture-curing epoxy coating under marine conditions is basically the same as that of Example 1, with the only difference being that the preparation method of the functional additive is different.

[0058] The preparation method of the functional additive is as follows:

[0059] S1. Add 40 g of 3,4,5-trihydroxybenzaldehyde and 20 g of 4,4'-diaminobenzophenone to 200 g of N,N-dimethylformamide, stir at 200 rpm for 30 min under a nitrogen atmosphere at 70°C, then react for 6 h under a nitrogen atmosphere at 70°C, add 25 wt% aqueous ethanol solution, filter through a 400 mesh sieve 5 times, collect the solid, and dry it in a vacuum at 90°C for 48 h to obtain a powder;

[0060] S2, 20g of the powder prepared in step S1, 92g of methyl epichlorohydrin and 1.8g of tetrabutylammonium bromide were mixed, stirred at 200rpm for 6h under a nitrogen atmosphere at 105°C, cooled to room temperature, and then 35g of a 30wt% aqueous sodium hydroxide solution was added in an ice-water bath, stirred at 200rpm for 6h at 60°C, and then the solvent was removed by rotary evaporation. The mixture was purified with a 30wt% aqueous dichloromethane solution and washed with water 5 times to obtain an organic layer, and the solvent was removed by rotary evaporation to obtain an oil;

[0061] S3. Add 10 g of the oil prepared in step S2 and 2.5 g of N-butyldiethanolamine to 50 g of anhydrous ethanol, stir at 200 rpm for 2 h to obtain a functional agent, add 1 g of acetic acid, stir at 200 rpm for 20 min to obtain a functional additive.

[0062] Comparative Example 3

[0063] The preparation method of a moisture-curing epoxy coating under marine conditions is basically the same as that of Example 1, with the only difference being that the preparation method of the functional additive is different.

[0064] The preparation method of the functional additive is as follows:

[0065] S1. Add 40 g of protocatechuic aldehyde and 20 g of 4,4'-diaminobenzophenone to 200 g of N,N-dimethylformamide, stir at 200 rpm for 30 min under a nitrogen atmosphere at 70°C, then react for 6 h under a nitrogen atmosphere at 70°C, add 25 wt% aqueous ethanol solution, filter through a 400 mesh sieve five times, collect the solid, and dry it in a vacuum at 90°C for 48 h to obtain a powder;

[0066] S2, 20g of the powder prepared in step S1, 92g of methyl epichlorohydrin and 1.8g of tetrabutylammonium bromide were mixed, stirred at 200rpm for 6h under a nitrogen atmosphere at 105°C, cooled to room temperature, and then 35g of a 30wt% aqueous sodium hydroxide solution was added in an ice-water bath, stirred at 200rpm for 6h at 60°C, and then the solvent was removed by rotary evaporation. The mixture was purified with a 30wt% aqueous dichloromethane solution and washed with water 5 times to obtain an organic layer, and the solvent was removed by rotary evaporation to obtain an oil;

[0067] S3. Add 10 g of the oil prepared in step S2 and 2.5 g of N-butyldiethanolamine to 50 g of anhydrous ethanol, stir at 200 rpm for 2 h to obtain a functional agent, add 1 g of acetic acid, stir at 200 rpm for 20 min to obtain a functional additive.

[0068] Comparative Example 4

[0069] A method for preparing a moisture-curing epoxy coating under marine conditions is as follows:

[0070] Step 1: 120 g of epoxy resin, 3 g of glyceryl monostearate, 2 g of fluorocarbon-modified polyacrylate leveling agent, and 5 g of vinyltriethoxysilane were added to a dispersion tank and dispersed at a speed of 900 rpm for 5 min to obtain a mixture;

[0071] Step 2: Add 25 g of talc and 25 g of zinc phosphate to the mixture prepared in step 1, disperse at 1200 rpm for 20 min, then add 2 g of polydimethyl polyether siloxane, and disperse at 1000 rpm for 5 min to obtain a dispersion;

[0072] Step 3: Add 40 g of ketimine curing agent to the dispersion prepared in step 2, and disperse at 60° C. and 600 rpm for 2 h to obtain an epoxy coating.

[0073] Test Example 1

[0074] Flame retardant and thermal insulation performance test

[0075] Before conducting the flame retardant and thermal insulation performance test, the prepared coating sample must be applied to the steel plate surface. The following points should be noted during the coating process:

[0076] (1) Before coating, the steel plate should be treated with rust removal and rust prevention, and sprayed with rust remover. After the rust is completely removed, avoid contact with water and allow it to dry naturally before use.

[0077] (2) Before applying the paint sample, stir it thoroughly with a glass rod to avoid precipitation of the paint after long-term storage.

[0078] (3) Use a glass rod to apply a thin layer of coating sample on one side of the treated steel plate and dry it under natural ventilation. The final coating amount is 500g / m 2 .

[0079] This test was conducted according to the large-plate combustion method specified in GB 12441-2018, "Fire-Retardant Coatings for Surfaces." The temperature rise of a steel structure coated with the epoxy coating of this invention under flame conditions for 300 seconds was used as a measure of its flame retardant and thermal insulation properties. The test results are shown in Table 1.

[0080] Table 1 Flame retardant and heat insulation performance test results

[0081] Experimental plan 300s temperature (℃) Example 1 113.4 Comparative Example 1 114.5 Comparative Example 2 138.4 Comparative Example 3 145.6 Comparative Example 4 168.0

[0082] Test Example 2

[0083] Antibacterial performance test

[0084] The tinplate was cut into a size of 40 mm × 40 mm × 3 mm, and its surface was cleaned and coated with the epoxy coating of the present invention at a coating amount of 500 g / m 2 Before the experiment, the coating was disinfected with an ultraviolet sterilization lamp for 5 minutes and then used as a standby. The bacterial solution dilutions of Escherichia coli (ATCC8739) and Staphylococcus aureus (ATCC43300) were taken as the test bacterial solution for the antibacterial coating, and a certain amount of bacterial solution was transferred to the surface of the sample coating. The covering film was then aligned and placed on the sample coating inoculated with the test night so that the bacterial solution could be evenly distributed in the interlayer. After culturing for 24 hours, 20 mL of the prepared 0.85% sodium chloride washing solution was taken to clean the sample test and the covering film surface, and then shaken thoroughly. Finally, the washing solution was inoculated into the culture medium; the number of viable bacteria in the sample was measured after culturing at 37°C for 24 hours, and the antibacterial rate of each paint film against Escherichia coli and Staphylococcus aureus was calculated.

[0085] R=(AB)A×100%

[0086] Where: R: antibacterial rate, %;

[0087] A: blank sample colony count, cfu / plate;

[0088] B: colony count of test sample, cfu / plate;

[0089] Each sample was tested in at least three parallel groups, and the average value of each sample was taken. The test results are shown in Table 2.

[0090] Table 2 Antibacterial performance test results

[0091]

[0092] From the test data in Tables 1 and 2, it can be seen that the epoxy coating prepared in Example 1 of the present invention has relatively excellent flame retardant and heat-insulating properties and antibacterial properties. The possible reason for the difference between Example 1 of the present invention and Comparative Example 1 is that 3,4,5-trihydroxybenzaldehyde has three hydroxyl groups, which makes the epoxy coating have a better hydrophilic surface. At the same time, the higher cross-linking density of the epoxy coating more effectively prevents water penetration, forms a hydration layer, prevents bacterial adsorption, and leads to a reduction in bacteria. In addition to the hydrophilic groups participating in preventing bacterial colony adhesion, the antibacterial effect of the formed Schiff base also plays a decisive role. The use of 3,4,5-trihydroxybenzaldehyde has advantages over the use of protocatechuic aldehyde as a functional additive in terms of antibacterial properties, and can improve the performance and durability of the prepared moisture-curing epoxy coating under marine conditions.

[0093] The reason for the difference between Example 1 and Comparative Example 2 may be that hexadecyltributylammonium bromide is a brominated flame retardant with good flame retardant and heat-insulating properties. It can react with free radicals in the combustion process at high temperatures, thereby inhibiting the spread of flames and the combustion process. In contrast, tetrabutylammonium bromide may be weaker in flame retardant and heat-insulating properties, so Example 1 has better flame retardant and heat-insulating properties and fireproofing capabilities. Ammonium bromide compounds have broad-spectrum antibacterial properties and can inhibit the growth and reproduction of a variety of microorganisms. Hexadecyltributylammonium bromide, as an ammonium bromide compound, can provide additional antibacterial protection in marine environments and reduce microbial attachment and corrosion problems on the coating surface.

Claims

1. A moisture-curing epoxy coating for marine conditions, characterized in that: The invention comprises the following raw materials in parts by weight: 100-140 parts of epoxy resin, 30-50 parts of curing agent, 20-30 parts of anti-rust pigment, 3-8 parts of silane coupling agent, 20-30 parts of filler, 2-4 parts of dispersant, 1-3 parts of leveling agent, 1-3 parts of defoaming agent, and 15-25 parts of functional additives; The preparation method of the functional additive is as follows, in parts by weight: S1. Add 30-50 parts of 3,4,5-trihydroxybenzaldehyde and 15-25 parts of 4,4'-diaminobenzophenone to 180-220 parts of N,N-dimethylformamide, stir at 100-300 rpm for 20-40 min under a nitrogen atmosphere at 60-80 ° C, then react for 4-8 h under a nitrogen atmosphere at 60-80 ° C, add 20-30 wt% ethanol aqueous solution, filter 3-6 times through a 200-600 mesh sieve, collect the solid, and dry it in a vacuum at 80-100 ° C for 20-50 h to obtain a powder; S2, 10 to 30 parts of the powder prepared in step S1, 80 to 100 parts of methyl epichlorohydrin and 1 to 2 parts of hexadecyltributylammonium bromide were mixed, and the mixture was stirred at 100 to 300 rpm for 4 to 8 hours under a nitrogen atmosphere at 100 to 110 ° C., and cooled to room temperature. Then, 30 to 40 parts of a 20 to 35 wt% aqueous sodium hydroxide solution were added in an ice-water bath, and the mixture was stirred at 100 to 300 rpm for 4 to 8 hours at 50 to 70 ° C., and the solvent was removed by rotary evaporation. The mixture was purified with a 20 to 35 wt% aqueous dichloromethane solution, and washed with water 1 to 5 times to obtain an organic layer. The solvent was removed by rotary evaporation to obtain an oily substance; S3. Add 8 to 12 parts of the oil prepared in step S2 and 2 to 3 parts of N-butyldiethanolamine to 40 to 60 parts of anhydrous ethanol, stir at 100 to 300 rpm for 1 to 3 hours to obtain a functional agent, add 0.5 to 2 parts of acetic acid, stir at 100 to 300 rpm for 10 to 30 minutes to obtain a functional additive.

2. The marine moisture-curing epoxy coating according to claim 1, wherein: The curing agent is at least one of a ketimine curing agent and an epoxy polyamide curing agent.

3. The marine moisture-curing epoxy coating according to claim 1, wherein: The silane coupling agent is at least one of vinyl triethoxysilane, aniline methyl triethoxysilane, γ-(2,3-epoxypropoxy)propyl trimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyl triethoxysilane.

4. The marine moisture-curing epoxy coating according to claim 1, wherein: The anti-rust pigment is at least one of zinc phosphate, red iron oxide, aluminum tripolyphosphate, zinc oxide, and molybdate.

5. The marine moisture-curing epoxy coating according to claim 1, wherein: The filler is at least one of talc powder, calcium carbonate, magnesium oxide, quartz powder, iron titanium powder, graphite powder and yumen clay.

6. The marine moisture-curing epoxy coating according to claim 1, wherein: The dispersant is at least one of fatty acids and aliphatic amides.

7. The marine moisture-curing epoxy coating according to claim 1, wherein: The leveling agent is a fluorocarbon leveling agent.

8. The marine moisture-curing epoxy coating according to claim 1, wherein: The defoaming agent is a polysiloxane defoaming agent.

9. A method for preparing a marine moisture-curing epoxy coating according to any one of claims 1 to 8, characterized in that: Here’s how: Step 1. Weigh the raw materials according to parts by weight, add the epoxy resin, dispersant, leveling agent, and silane coupling agent into a dispersion tank, and disperse at a speed of 500-1500 rpm for 3-8 minutes to obtain a mixture; Step 2: Add filler and anti-rust pigment to the mixture prepared in step 1, disperse at a speed of 1000-1500 rpm for 10-30 min, then add defoamer and functional additives, and disperse at a speed of 500-1500 rpm for 3-8 min to obtain a dispersion; Step 3: Add a curing agent to the dispersion prepared in step 2, and disperse at 50-70° C. and 600 rpm for 2 h to obtain an epoxy coating.

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