High-corrosion-resistance water-borne epoxy resin-based heavy anti-corrosion coating for marine steel structure and preparation method thereof

Abstract

The invention relates to the technical field of water-based anticorrosive coatings, in particular to a high-corrosion-resistance water-based epoxy resin-based heavy-duty anticorrosive coating for a marine steel structure and a preparation method of the high-corrosion-resistance water-based epoxy resin-based heavy-duty anticorrosive coating. Comprising the following raw materials in parts by weight: 10-30 parts of modified epoxy resin, 1-10 parts of modified graphene, 30-60 parts of nano zinc powder, 15-30 parts of inorganic filler, 12-21 parts of water-based fluorocarbon resin, 1-3 parts of a dispersing agent, 1-5 parts of an auxiliary agent, 4-12 parts of a cosolvent and 5-10 parts of a curing agent. According to the high-performance environment-friendly coating combining the excellent performance of the graphene and the cathode protection effect of the zinc powder, the graphene nanometer material is introduced into a water-based zinc-rich coating system, and the corrosion resistance, the mechanical performance and the environment-friendly characteristic of a coating are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water-based anti-corrosion coatings, and more particularly to a highly corrosion-resistant water-based epoxy resin-based heavy-duty anti-corrosion coating for marine steel structures and a preparation method thereof. Background Art

[0002] Heavy-duty anti-corrosion coatings, as a key engineering material in key sectors of the national economy, are crucial to their quality and added value, particularly in transportation, petrochemicals, electric power, marine engineering, and construction. They also lay the foundation for the development of high-tech industries such as marine development and new energy, aerospace, warships, and defense. Consequently, the level of development of heavy-duty anti-corrosion coatings has been internationally used as a benchmark for the advancement of the coatings industry. Furthermore, with China vigorously developing its environmental protection industry, water-based heavy-duty anti-corrosion coatings, with their undeniable environmental advantages, hold enormous development prospects as a key engineering material in the national economy and military defense.

[0003] The core function of marine anti-corrosion powder coatings is to provide long-term corrosion resistance and maintain coating integrity. Given the unique characteristics of the marine environment, such as high salinity, high humidity, intense UV radiation, and tidal effects, these coatings must possess excellent weather resistance, salt spray resistance, water resistance, and good mechanical properties. These performance requirements ensure the coating's long-term stability and durability in the marine environment, effectively protecting the substrate from corrosion and damage.

[0004] Although the new water-based high-solid graphene zinc heavy-duty anti-corrosion coating has significant anti-corrosion performance and environmental advantages, it also has some disadvantages: the dispersion problem of graphene: the graphene sheet structure is neither hydrophilic nor lipophilic, easy to agglomerate, and difficult to stably disperse in the aqueous system, which may affect the uniformity and performance of the coating. Summary of the Invention

[0005] The present invention provides a highly corrosion-resistant water-based epoxy resin-based heavy-duty anti-corrosion coating for marine steel structures and a preparation method thereof. The high-performance environmentally friendly coating combines the excellent properties of graphene and the cathodic protection effect of zinc powder. This coating significantly improves the corrosion resistance, mechanical properties and environmental characteristics of the coating by introducing graphene nanomaterials into the water-based zinc-rich coating system.

[0006] In a first aspect, the present invention provides a highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures, comprising the following raw materials in parts by weight:

[0007] The invention comprises 10 to 30 parts of modified epoxy resin, 1 to 10 parts of modified graphene, 30 to 60 parts of nano zinc powder, 15 to 30 parts of inorganic filler, 12 to 21 parts of water-based fluorocarbon resin, 1 to 3 parts of dispersant, 1 to 5 parts of auxiliary agent, 4 to 12 parts of cosolvent and 5 to 10 parts of curing agent. The modified graphene is silicon dioxide-graphene oxide, which is prepared by surface-modifying graphene with nano silicon dioxide. The modified epoxy resin is prepared by modifying water-based epoxy resin with chitosan quaternary ammonium salt, which is prepared by direct quaternization method, wherein quaternary ammonium groups are introduced into the chitosan molecular chain through chemical modification.

[0008] Preferably, the silicon dioxide-graphene oxide is prepared by grafting nano-silicon dioxide onto the surface of graphene using a silane coupling agent 3-aminopropyltriethoxysilane.

[0009] Preferably, the modified epoxy resin is prepared by modifying waterborne epoxy resin with chitosan quaternary ammonium salt using a phase inversion method.

[0010] Preferably, the preparation method of silicon dioxide-graphene oxide comprises the following steps:

[0011] A1: First, measure anhydrous ethanol, then add graphene oxide and 3-aminopropyltriethoxysilane. After thorough mixing and ultrasonic dispersion, heat in a water bath and stir evenly. Slowly inject deionized water during stirring. After heating to 60-80°C, let it stand for 24 hours. Then remove the lower sediment, rinse with water, centrifuge, freeze-dry, and obtain highly functionalized graphene oxide powder.

[0012] A2: First, measure anhydrous ethanol, then add nano-SiO2 and 3-aminopropyltriethoxysilane. After thorough mixing and ultrasonic dispersion, heat in a water bath and stir evenly. During the stirring process, slowly inject deionized water. After heating to 60-80℃, let it stand for 24 hours. Then remove the lower sediment, rinse with water, centrifuge, freeze and dry to obtain functionalized silicon oxide powder.

[0013] A3: Measure DMF, mix the powder of highly functionalized graphene oxide and the powder of functionalized silicon oxide in a mass ratio of 1:2-4, add to DMF, add the powder of functionalized graphene oxide, ultrasonicate to form a uniform suspension, then add the powder of functionalized silicon oxide, ultrasonicate again to form a uniform suspension, heat the reaction in an oil bath at 105-120°C, at a speed of 400-600 r / min, let it stand after heating, remove the lower layer of sediment, wash with water, centrifuge, and freeze-dry to obtain silicon dioxide-graphene oxide.

[0014] Preferably, the preparation method of the modified epoxy resin comprises the following steps: synthesizing an emulsifier using polyethylene glycol and bisphenol A epoxy resin as raw materials, and preparing a water-based epoxy resin with a solid content of 75% by a phase inversion method at a mass ratio of emulsifier to epoxy resin of (20-32): (65-75); then adding chitosan quaternary ammonium salt thereto, and stirring evenly to obtain a water-based epoxy resin modified with chitosan quaternary ammonium salt.

[0015] Preferably, the inorganic filler includes one or more of talc, bentonite, mica iron oxide, ferro-titanium powder, ferrophosphorus powder, titanium dioxide, hollow glass microspheres, and ceramic microspheres; the dispersant includes one or more of sodium hexametaphosphate, sodium pyrophosphate, and tourmaline powder.

[0016] Preferably, the auxiliary agent is a defoaming agent, a wetting agent, an anti-settling agent, a leveling agent or / and a film-forming auxiliary agent;

[0017] The cosolvent is one or more of ethanol, ethylene glycol butyl ether, propylene glycol methyl ether acetate, propylene glycol methyl ether, propylene glycol butyl ether, dipropylene glycol methyl ether, and dipropylene glycol butyl ether;

[0018] The curing agent is one or more of trimethylhexamethylenediamine, di(hexamethylene)triamine, hexamethylenediamine, trimethylhexamethylenediamine, diethylamine, polyetherdiamine, m-phenylenediamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, m-aminomethylamine, benzidine, chloro-o-phenylenediamine, phenylenediamine trimer, phenylenediamine trimer derivative, bisbenzylamino ether or phenylenediamine.

[0019] In a second aspect, the present invention provides a method for preparing a highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures, comprising the following steps:

[0020] (1) Weigh the modified epoxy resin, modified graphene, nano zinc powder, inorganic filler, water-based fluorocarbon resin, dispersant, additive, cosolvent and curing agent according to the weight ratio;

[0021] (2) Mix the modified epoxy resin, modified graphene, nano zinc powder, inorganic filler, water-based fluorocarbon resin and dispersant, stir and disperse at high speed for 1-2 hours to make the powder evenly dispersed in the resin solution, then add the additive and continue stirring to obtain the coating slurry;

[0022] (3) Add the co-solvent and curing agent into the coating slurry and mix them evenly to prepare a highly corrosion-resistant water-based epoxy resin-based heavy-duty anti-corrosion coating for marine steel structures.

[0023] In summary, the present invention has the following beneficial effects:

[0024] 1. The present invention solves the problem of biopolymerization of graphene oxide and improves its biological dispersibility and compatibility in epoxy resin aqueous solution. Various inorganic nanomaterials, silicon dioxide and titanium dioxide are used to biologically modify graphene oxide to produce various inorganic nanocomposites with various mass ratios. These are then added to epoxy resin to produce epoxy anti-corrosion coatings with good performance.

[0025] 2. The addition of graphene to the present invention not only enhances the physical shielding properties of the coating but also improves the coating's cathodic protection by forming a conductive network with zinc powder. Chitosan contains active groups such as hydroxyl and amino groups, which can act as a curing agent or modifier for epoxy resins, reacting with epoxy prepolymers to improve material properties. Quaternary ammonium-modified chitosan can be directly dispersed in water and exhibits more effective antibacterial properties than unmodified chitosan. Quaternary ammonium salts of chitosan can not only be evenly dispersed in water-based epoxy resin systems but also improve the mechanical properties of the material after curing.

[0026] 3. This highly corrosion-resistant, water-based epoxy resin-based heavy-duty anticorrosive coating for marine steel structures combines the superior properties of graphene with the cathodic protection of zinc powder. By incorporating graphene nanomaterials into a water-based zinc-rich coating system, this coating significantly enhances the coating's corrosion resistance, mechanical properties, and environmental performance.

[0027] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and are not intended to limit the scope of protection of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the examples. It is particularly noted that if no specific conditions are specified in the following examples, the reactions were carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0029] Preparation Example

[0030] Preparation Example 1

[0031] The preparation method of silicon dioxide-graphene oxide comprises the following steps:

[0032] A1: First, measure 100 mL of anhydrous ethanol, then add 5 g of graphene oxide and 2 g of 3-aminopropyltriethoxysilane. After thorough mixing and ultrasonic dispersion, heat in a water bath and stir evenly. During the stirring process, slowly inject 500 mL of deionized water. After heating, let it stand at low temperature for 24 hours. Then, remove the lower sediment, rinse with water, centrifuge, freeze-dry, and obtain highly functionalized graphene oxide powder.

[0033] A2: First, measure 100 mL of anhydrous ethanol, then add 3.5 g of nano-SiO2 and 2.5 g of 3-aminopropyltriethoxysilane. After thorough mixing and ultrasonic dispersion, heat in a water bath and stir evenly. During the stirring process, slowly inject 200 mL of deionized water. After heating, let it stand at low temperature for 24 hours. Then remove the lower sediment, rinse with water, centrifuge, freeze-dry, and obtain functionalized silica powder.

[0034] A3: Measure 50 mL of DMF, mix the highly functionalized graphene oxide powder prepared by A1 and the functionalized silicon oxide powder prepared by A2 in a mass ratio of 1:2, and add them to DMF. The specific steps are: add the highly functionalized graphene oxide powder, ultrasonically treat to form a uniform suspension, then add the functionalized silicon oxide powder, and ultrasonically treat again to form a uniform suspension, heat the reaction in an oil bath at 105°C, at a speed of 400 r / min, let it stand after heating, remove the lower layer of sediment, wash with water, centrifuge, and freeze-dry to obtain silicon dioxide-graphene oxide.

[0035] Preparation Example 2

[0036] The preparation method of silicon dioxide-graphene oxide comprises the following steps:

[0037] A1: First, measure 100 mL of anhydrous ethanol, then add 3 g of graphene oxide and 5 g of 3-aminopropyltriethoxysilane. After thorough mixing and ultrasonic dispersion, heat in a water bath and stir evenly. During the stirring process, slowly inject 200 mL of deionized water. After heating, let it stand at low temperature for 24 hours. Then, remove the lower layer of sediment, rinse with water, centrifuge, freeze-dry, and obtain highly functionalized graphene oxide powder.

[0038] A2: First, measure 150 mL of anhydrous ethanol, then add 4.2 g of nano-SiO2 and 3.8 g of 3-aminopropyltriethoxysilane. After thorough mixing and ultrasonic dispersion, heat in a water bath and stir evenly. During the stirring process, slowly inject 200 mL of deionized water. After heating, let it stand at low temperature for 24 hours. Then remove the lower sediment, rinse with water, centrifuge, freeze-dry, and obtain functionalized silica powder.

[0039] A3: Measure 100 mL of DMF, mix the highly functionalized graphene oxide powder prepared by A1 and the functionalized silicon oxide powder prepared by A2 in a mass ratio of 1:3, and add them to DMF. The specific steps are: add the highly functionalized graphene oxide powder, ultrasonically treat to form a uniform suspension, then add the functionalized silicon oxide powder, and ultrasonically treat again to form a uniform suspension, heat the reaction in an oil bath at 110°C, with a speed of 600 r / min, let it stand after heating, remove the lower layer of sediment, wash with water, centrifuge, and freeze-dry to obtain silicon dioxide-graphene oxide.

[0040] Preparation Example 3

[0041] The preparation method of silicon dioxide-graphene oxide comprises the following steps:

[0042] A1: First, measure 200 mL of anhydrous ethanol, then add 5.5 g of graphene oxide and 1.8 g of 3-aminopropyltriethoxysilane. After thorough mixing and ultrasonic dispersion, heat in a water bath and stir evenly. During the stirring process, slowly inject 300 mL of deionized water. After heating, let it stand at low temperature for 24 hours. Then, remove the lower layer of sediment, rinse with water, centrifuge, freeze-dry, and obtain highly functionalized graphene oxide powder.

[0043] A2: First, measure 200 mL of anhydrous ethanol, then add 4.5 g of nano-SiO2 and 3.2 g of 3-aminopropyltriethoxysilane. After thorough mixing and ultrasonic dispersion, heat in a water bath and stir evenly. During the stirring process, slowly inject 100 mL of deionized water. After heating, let it stand at low temperature for 24 hours. Then remove the lower sediment, rinse with water, centrifuge, freeze-dry, and obtain functionalized silica powder.

[0044] A3: Measure 100 mL of DMF, mix the highly functionalized graphene oxide powder prepared by A1 and the functionalized silicon oxide powder prepared by A2 in a mass ratio of 1:4, and add them to DMF. The specific steps are: add the highly functionalized graphene oxide powder, ultrasonically treat to form a uniform suspension, then add the functionalized silicon oxide powder, and ultrasonically treat again to form a uniform suspension, heat the reaction in an oil bath at 120°C, with a speed of 600 r / min, let it stand after heating, remove the lower layer of sediment, wash with water, centrifuge, and freeze-dry to obtain silicon dioxide-graphene oxide.

[0045] Preparation Example 4

[0046] The preparation method of the modified epoxy resin comprises the following steps: synthesizing an emulsifier using polyethylene glycol and bisphenol A epoxy resin as raw materials, preparing a water-based epoxy resin with a solid content of 75% by a phase inversion method at a mass ratio of the emulsifier to the epoxy resin of 21:79; then adding 25g of chitosan quaternary ammonium salt to the emulsifier, and stirring evenly to obtain a water-based epoxy resin modified with the chitosan quaternary ammonium salt.

[0047] Preparation Example 5

[0048] The method for preparing a modified epoxy resin comprises the following steps: synthesizing an emulsifier using polyethylene glycol and bisphenol A epoxy resin as raw materials, preparing a water-based epoxy resin with a solid content of 75% by a phase inversion method at a mass ratio of the emulsifier to the epoxy resin of 24:76; then adding 32 g of chitosan quaternary ammonium salt to the emulsifier, and stirring evenly to obtain a water-based epoxy resin modified with the chitosan quaternary ammonium salt.

[0049] Preparation Example 6

[0050] The preparation method of the modified epoxy resin comprises the following steps: synthesizing an emulsifier using polyethylene glycol and bisphenol A epoxy resin as raw materials, preparing a water-based epoxy resin with a solid content of 75% by a phase inversion method at a mass ratio of the emulsifier to the epoxy resin of 25:75; then adding 45g of chitosan quaternary ammonium salt to the emulsifier, and stirring evenly to obtain a water-based epoxy resin modified with the chitosan quaternary ammonium salt.

[0051] Example

[0052] Example 1

[0053] A highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures, comprising the following raw materials:

[0054] 15g of the water-based epoxy resin modified with chitosan quaternary ammonium salt prepared in Preparation Example 4, 1g of the silicon dioxide-graphene oxide prepared in Preparation Example 1, 60g of nano-zinc powder, 10g of inorganic filler, 12g of water-based fluorocarbon resin, 1g of dispersant, 3g of auxiliary agent, 10g of cosolvent, and 5g of curing agent.

[0055] The inorganic filler is a mixture of ferro-titanium powder, bentonite, mica iron oxide, and titanium dioxide in a weight ratio of 1:1:1:2; the additives are a defoamer, a wetting agent, an anti-settling agent, and a leveling agent, and the weight ratio of the defoamer, wetting agent, anti-settling agent, and leveling agent is 1:2:1:1; the cosolvent is propylene glycol methyl ether; the curing agent is trimethylhexamethylenediamine; and the dispersant is polyvinyl alcohol.

[0056] A method for preparing a highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures comprises the following steps:

[0057] (1) Weigh chitosan quaternary ammonium salt modified waterborne epoxy resin, silicon dioxide-graphene oxide, nano zinc powder, inorganic filler, waterborne fluorocarbon resin, dispersant, additive, cosolvent, and curing agent according to weight ratio;

[0058] (2) Chitosan quaternary ammonium salt-modified water-based epoxy resin, silica-graphene oxide, nano zinc powder, inorganic filler, water-based fluorocarbon resin and dispersant were mixed and dispersed at a high speed of 800 rpm for 1 h to uniformly disperse the powder in the resin solution. Then, the additive was added and the stirring was continued at a speed of 800 rpm to obtain a coating slurry;

[0059] (3) Add the co-solvent and curing agent into the coating slurry and mix them evenly to prepare a water-based high-solid new graphene zinc heavy-duty anti-corrosion coating.

[0060] Example 2

[0061] A highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures, comprising the following raw materials:

[0062] 20g of the chitosan quaternary ammonium salt-modified water-based epoxy resin prepared in Preparation Example 5, 3g of the silicon dioxide-graphene oxide prepared in Preparation Example 2, 50g of nano-zinc powder, 20g of inorganic filler, 15g of water-based fluorocarbon resin, 1g of dispersant, 2g of auxiliary agent, 10g of cosolvent, and 8g of curing agent.

[0063] The inorganic filler is a mixture of ferrophosphorus powder, bentonite, mica iron oxide, and titanium dioxide in a weight ratio of 1:1:2:2; the additives are a defoamer, a wetting agent, an anti-settling agent, and a leveling agent, and the weight ratio of the defoamer, wetting agent, anti-settling agent, and leveling agent is 1:1:2:1; the cosolvent is propylene glycol methyl ether; the curing agent is trimethylhexamethylenediamine; and the dispersant is polyvinyl alcohol.

[0064] A method for preparing a highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures comprises the following steps:

[0065] (1) Weigh chitosan quaternary ammonium salt modified waterborne epoxy resin, silicon dioxide-graphene oxide, nano zinc powder, inorganic filler, waterborne fluorocarbon resin, dispersant, additive, cosolvent, and curing agent according to weight ratio;

[0066] (2) Chitosan quaternary ammonium salt-modified water-based epoxy resin, silica-graphene oxide, nano zinc powder, inorganic filler, water-based fluorocarbon resin and dispersant were mixed and dispersed at a high speed of 900 rpm for 2 h to uniformly disperse the powder in the resin solution. Then, the additive was added and the stirring was continued at a speed of 900 rpm to obtain a coating slurry;

[0067] (3) Add the cosolvent and curing agent to the coating slurry and mix them evenly to prepare a water-based high-solid new graphene zinc heavy-duty anti-corrosion coating.

[0068] Example 3

[0069] A highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures, comprising the following raw materials:

[0070] 25g of the water-based epoxy resin modified with chitosan quaternary ammonium salt prepared in Preparation Example 6, 5g of silicon dioxide-graphene oxide prepared in Preparation Example 3, 40g of nano zinc powder, 25g of inorganic filler, 18g of water-based fluorocarbon resin, 1g of dispersant, 2g of auxiliary agent, 11g of cosolvent, and 6g of curing agent.

[0071] The inorganic filler is a mixture of ferro-titanium powder, bentonite, mica iron oxide, and titanium dioxide in a weight ratio of 2:1:1:2; the additives are a defoamer, a wetting agent, an anti-settling agent, and a leveling agent, and the weight ratio of the defoamer, wetting agent, anti-settling agent, and leveling agent is 2:1:1:1; the cosolvent is propylene glycol methyl ether; the curing agent is trimethylhexamethylenediamine; and the dispersant is polyvinyl alcohol.

[0072] A method for preparing a highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures comprises the following steps:

[0073] (1) Weigh chitosan quaternary ammonium salt modified waterborne epoxy resin, silicon dioxide-graphene oxide, nano zinc powder, inorganic filler, waterborne fluorocarbon resin, dispersant, additive, cosolvent, and curing agent according to weight ratio;

[0074] (2) Chitosan quaternary ammonium salt-modified water-based epoxy resin, silica-graphene oxide, nano zinc powder, inorganic filler, water-based fluorocarbon resin and dispersant were mixed and dispersed at a high speed of 1000 rpm for 1 h to uniformly disperse the powder in the resin solution. Then, the additive was added and the stirring was continued at a speed of 1000 rpm to obtain a coating slurry;

[0075] (3) Add the co-solvent and curing agent into the coating slurry and mix them evenly to prepare a water-based high-solid new graphene zinc heavy-duty anti-corrosion coating.

[0076] Example 4

[0077] A highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures, comprising the following raw materials:

[0078] 30g of the water-based epoxy resin modified with chitosan quaternary ammonium salt prepared in Preparation Example 4, 10g of silicon dioxide-graphene oxide prepared in Preparation Example 1, 30g of nano-zinc powder, 30g of inorganic filler, 17g of water-based fluorocarbon resin, 5g of dispersant, 30g of auxiliary agent, 12g of co-solvent, and 10g of curing agent.

[0079] The inorganic filler is a mixture of ferro-titanium powder, bentonite, mica iron oxide, and titanium dioxide in a weight ratio of 1:1:1:1; the additives are a defoamer, a wetting agent, an anti-settling agent, and a leveling agent, and the weight ratio of the defoamer, wetting agent, anti-settling agent, and leveling agent is 1:1:1:2; the cosolvent is propylene glycol methyl ether; the curing agent is trimethylhexamethylenediamine; and the dispersant is polyvinyl alcohol.

[0080] A method for preparing a highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures comprises the following steps:

[0081] (1) Weigh chitosan quaternary ammonium salt modified waterborne epoxy resin, silicon dioxide-graphene oxide, nano zinc powder, inorganic filler, waterborne fluorocarbon resin, dispersant, additive, cosolvent, and curing agent according to weight ratio;

[0082] (2) Chitosan quaternary ammonium salt-modified water-based epoxy resin, silica-graphene oxide, nano zinc powder, inorganic filler, water-based fluorocarbon resin and dispersant were mixed and dispersed at a high speed of 800 rpm for 2 h to uniformly disperse the powder in the resin solution. Then, the additive was added and the stirring was continued at a speed of 800 rpm to obtain a coating slurry;

[0083] (3) Add the cosolvent and curing agent to the coating slurry and mix them evenly to prepare a water-based high-solid new graphene zinc heavy-duty anti-corrosion coating.

[0084] Comparative Example 1

[0085] The highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures was prepared according to the method of Example 2, except that the waterborne epoxy resin modified with chitosan quaternary ammonium salt was not added.

[0086] Comparative Example 2

[0087] The highly corrosion-resistant waterborne epoxy resin-based heavy-duty anti-corrosion coating for marine steel structures was prepared according to the method of Example 2, except that silicon dioxide-graphene oxide was not added.

[0088] Comparative Example 3

[0089] The highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures was prepared according to the method of Example 2, except that no nano zinc powder was added.

[0090] Comparative Example 4

[0091] The highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures was prepared according to the method of Example 2, except that no inorganic filler was added.

[0092] Performance Testing

[0093] 1. Determination of non-volatile matter content: The specific determination method in GB / T1725 standard is the determination of non-volatile matter content. According to the provisions of GB / T1725-2007, the test steps are as follows:

[0094] (1) Sample preparation: Mix the components of the product in the proportion specified by the manufacturer and then test.

[0095] (2) Sample weight: Weigh (2.5 ± 0.2) g of sample.

[0096] (3) Baking conditions: Bake at (105±2)℃ for 2 hours.

[0097] 2. Determination of metallic zinc content in non-volatile matter: According to the HG / T3668-2020 "Zinc-rich Primer" standard, the metallic zinc content is determined by differential scanning calorimetry (DSC) by comparing the endothermic peak calorific value of the sample with that of pure zinc.

[0098] Table 1 Determination results of non-volatile matter content and metallic zinc content in non-volatile matter of coatings prepared in Examples 1-4 and Comparative Examples 1-4

[0099]

[0100] Non-volatile matter content is one of the key indicators for coating quality control. By measuring the non-volatile matter content, it can be ensured that the content of solid components (such as resins, pigments, fillers, etc.) in the coating meets the standard requirements, thereby ensuring the wear resistance, durability and chemical stability of the coating. The water-based high-solid novel graphene zinc heavy-duty anti-corrosion coating prepared by the present invention has good chemical stability and is mainly used for corrosion protection of steel substrates. The metallic zinc content in the non-volatile matter directly affects the anti-corrosion performance of the coating. As a cathodic protection material, the higher the content of metallic zinc, the better the anti-corrosion effect of the coating. The high-corrosion-resistant water-based epoxy resin-based heavy-duty anti-corrosion coating for marine steel structures prepared by the present invention has a metallic zinc content of ≥60%, and its corrosion resistance is significantly better than that of ordinary coatings.

[0101] 3. Corrosion resistance test:

[0102] Refer to GB / T9274-1988 standard for coating water resistance, acid resistance and alkali resistance test; refer to GB / T1771-2007 standard for coating neutral salt spray resistance test;

[0103] 4. Adhesion test

[0104] According to the GB / T9286-1998 cross-hatch test standard for paint films, first place the painted sample on a flat surface. Using a crosshatch cutter, apply even pressure perpendicular to the sample surface and steadily score at least six parallel cuts. Next, cross six parallel cuts perpendicular to the initial cuts at 90° angles to form a grid pattern. It's important to note that all cuts must penetrate the substrate surface. After cleaning the lines in the grid, apply tape to the center of the grid, ensuring full contact with the paint film. Lift the tape to approximately a 60° angle with the sample and remove it continuously and steadily. Observe the paint film in the grid for any signs of shedding. Compare and grade the test results according to the table.

[0105] 5. Initial drying crack resistance test:

[0106] According to the GB / T9779-2015 standard, an axial flow fan was used to supply air. The test panels were NAFHV-grade asbestos-free fiber cement boards with a thickness of 4mm-6mm and a size of 600×400mm. The coating thickness was ≤1.5mm. The coated test panels were placed on the test panel rack in the wind tunnel. The fan was started and the air volume control device was used to adjust the wind speed within 3m / s±0.3m / s. The air drying time was 10 hours. After the time was up, the machine automatically stopped and the test panels were inspected for cracks.

[0107] Table 2 Performance test results of the coatings prepared in Examples 1-4 and Comparative Examples 1-4

[0108]

[0109] The test results show that the highly corrosion-resistant waterborne epoxy resin-based heavy-duty anti-corrosion coating for marine steel structures is a high-performance, environmentally friendly coating that combines the excellent properties of graphene with the cathodic protection of zinc powder, and has significant advantages in crack resistance. The coatings in Examples 1-4 showed no cracks in the initial drying crack resistance test, while Comparative Examples 1-4 showed varying degrees of cracking. This indicates that the addition of chitosan quaternary ammonium salt-modified waterborne epoxy resin and silica-graphene oxide plays an important role in improving the crack resistance of the coating.

[0110] The addition of graphene not only enhances the coating's physical shielding properties but also improves its cathodic protection by forming a conductive network with zinc powder. Chitosan contains reactive groups such as hydroxyl and amino groups, which can act as a curing agent or modifier for epoxy resins, reacting with epoxy prepolymers to enhance material properties. Quaternary ammonium-modified chitosan can be directly dispersed in water and exhibits more effective antibacterial properties than unmodified chitosan. Quaternary ammonium salts of chitosan can not only be evenly dispersed in water-based epoxy resin systems but also enhance the mechanical properties of the material after curing.

[0111] The foregoing description is merely an exemplary embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures, characterized in that: The raw materials include the following parts by weight: The invention comprises 10 to 30 parts of modified epoxy resin, 1 to 10 parts of modified graphene, 30 to 60 parts of nano zinc powder, 15 to 30 parts of inorganic filler, 12 to 21 parts of water-based fluorocarbon resin, 1 to 3 parts of dispersant, 1 to 5 parts of auxiliary agent, 4 to 12 parts of cosolvent and 5 to 10 parts of curing agent. The modified graphene is silicon dioxide-graphene oxide, which is prepared by surface-modifying graphene with nano silicon dioxide. The modified epoxy resin is prepared by modifying water-based epoxy resin with chitosan quaternary ammonium salt, which is prepared by direct quaternization method, wherein quaternary ammonium groups are introduced into the chitosan molecular chain through chemical modification.

2. The highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures according to claim 1, characterized in that: The silicon dioxide-graphene oxide is prepared by grafting nano-silicon dioxide onto the surface of graphene using a silane coupling agent, 3-aminopropyltriethoxysilane.

3. The highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures according to claim 1, characterized in that: The modified epoxy resin is prepared by modifying waterborne epoxy resin with chitosan quaternary ammonium salt using a phase inversion method.

4. The highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures according to claim 1, characterized in that: The preparation method of the silicon dioxide-graphene oxide comprises the following steps: A1: First, measure anhydrous ethanol, then add graphene oxide and 3-aminopropyltriethoxysilane. After thorough mixing and ultrasonic dispersion, heat in a water bath and stir evenly. During the stirring process, add deionized water. After heating to 60-80°C, let it stand for 24 hours. Then remove the lower sediment, rinse with water, centrifuge, freeze and dry to obtain graphene oxide powder. A2: First, measure anhydrous ethanol, then add nano-SiO2 and 3-aminopropyltriethoxysilane. After thorough mixing and ultrasonic dispersion, heat in a water bath and stir evenly. During the stirring process, inject deionized water. After heating to 60-80℃, let it stand for 24 hours. Then remove the lower sediment, rinse with water, centrifuge, freeze and dry to obtain functionalized silicon oxide powder. A3: Measure DMF, mix the powder of highly functionalized graphene oxide and the powder of functionalized silicon oxide in a mass ratio of 1:2-4, add to DMF, add the powder of functionalized graphene oxide, ultrasonicate to form a uniform suspension, then add the powder of functionalized silicon oxide, ultrasonicate again to form a uniform suspension, heat the reaction in an oil bath at 105-120°C, at a speed of 400-600 r / min, let it stand after heating, remove the lower layer of sediment, wash with water, centrifuge, and freeze-dry to obtain silicon dioxide-graphene oxide.

5. The highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures according to claim 1, characterized in that: The modified epoxy resin preparation method comprises the following steps: synthesizing an emulsifier using polyethylene glycol and bisphenol A epoxy resin as raw materials, and preparing a water-based epoxy resin with a solid content of 75% by a phase inversion method at a mass ratio of emulsifier to epoxy resin of (20-32):(65-75); then adding chitosan quaternary ammonium salt to the emulsifier, and stirring evenly to obtain a water-based epoxy resin modified with chitosan quaternary ammonium salt.

6. The highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures according to claim 1, characterized in that: The inorganic filler includes one or more of talc, bentonite, mica iron oxide, ferro-titanium powder, ferrophosphorus powder, titanium dioxide, hollow glass microspheres, and ceramic microspheres; the dispersant includes one or more of sodium hexametaphosphate, sodium pyrophosphate, and tourmaline powder.

7. The highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures according to claim 1, characterized in that: The auxiliary agent is a defoaming agent, a wetting agent, an anti-settling agent, a leveling agent and / or a film-forming agent; The cosolvent is one or more of ethanol, ethylene glycol butyl ether, propylene glycol methyl ether acetate, propylene glycol methyl ether, propylene glycol butyl ether, dipropylene glycol methyl ether, and dipropylene glycol butyl ether; The curing agent is one or more of trimethylhexamethylenediamine, di(hexamethylene)triamine, hexamethylenediamine, trimethylhexamethylenediamine, diethylamine, polyetherdiamine, m-phenylenediamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, m-aminomethylamine, benzidine, chloro-o-phenylenediamine, phenylenediamine trimer, phenylenediamine trimer derivative, bisbenzylamino ether or phenylenediamine.

8. The method for preparing a highly corrosion-resistant waterborne epoxy resin-based heavy-duty anticorrosive coating for marine steel structures according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Weigh the modified epoxy resin, modified graphene, nano zinc powder, inorganic filler, water-based fluorocarbon resin, dispersant, additive, cosolvent and curing agent according to the weight ratio; (2) Mix the modified epoxy resin, modified graphene, nano zinc powder, inorganic filler, water-based fluorocarbon resin and dispersant, stir and disperse for 1-2 hours to make the powder evenly dispersed in the resin solution, then add the additive and continue stirring to obtain the coating slurry; (3) Add the co-solvent and curing agent into the coating slurry and mix them evenly to prepare a highly corrosion-resistant water-based epoxy resin-based heavy-duty anti-corrosion coating for marine steel structures.

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