Waterborne epoxy resin coating as well as preparation method and application thereof

Abstract

The invention discloses a water-borne epoxy resin coating which comprises a component A and a component B, the component A is prepared from 60 to 80 parts of 50 percent modified water-borne epoxy resin emulsion, 5 to 15 parts of deionized water, 0.5 to 1 part of wetting dispersant, 0.2 to 0.8 part of defoaming agent, 5 to 10 parts of modified zinc phosphate, 3 to 5 parts of ion exchange antirust pigment, 4 to 6 parts of sericite powder, 3 to 5 parts of glass flake, 5 to 10 parts of precipitated barium sulphate, 1 to 5 parts of nano silicon dioxide and 0.5 to 1 part of rheological additive; 1 to 2 parts of modified organic bentonite slurry; 0.1 to 0.3 part of a pH conditioning agent; and 0.2 to 0.8 part of a flash rust inhibitor. The component B is prepared from 40 to 50 parts of waterborne epoxy-amine adduct, 20 to 30 parts of 50 percent modified polyamide curing agent, 5 to 15 parts of 60 percent Mannich base phenolic aldehyde amine curing agent, 0.5 to 1.5 parts of epoxy silane coupling agent, 1 to 2 parts of nonionic surfactant and 15 to 20 parts of deionized water. The emulsion stability of the waterborne epoxy resin coating is improved through a bisphenol A / F mixed epoxy emulsion and a grafted polyethylene glycol hydrophilic chain segment.

Description

Technical Field

[0001] The present invention relates to the technical field of water-based coatings, in particular to a water-based epoxy resin coating. Background Art

[0002] Waterborne epoxy resin coatings are environmentally friendly coatings that use water as a dispersion medium. Their core film-forming substance is epoxy resin, chemically modified to enable stable dispersion (rather than dissolution) in water. This resin then reacts with a water-based curing agent to form a three-dimensional crosslinked network. Specifically, waterborne epoxy resin coatings are based on a hydrophilically modified epoxy resin emulsion (Component A) that undergoes a cross-linking reaction with a water-based amine curing agent (Component B) to form a film. The core technology behind waterborne epoxy resin coatings lies in the stable dispersion of epoxy resin in water (particle size 0.1-1μm) through chemical grafting of polyether segments or a self-emulsification process. This results in a VOC content of less than 50g / L, a reduction of over 90% compared to solvent-based coatings. The core features of existing water-based epoxy resin coatings include environmental protection and safety - using water as the dispersion medium, there is no flammable or explosive risk, and it complies with green regulations; construction advantages - it can be directly coated on damp substrates and supports a single layer of 300μm thick coating without blistering; performance balance - salt spray resistance reaches 1000-1500 hours, but the curing speed is relatively slow; wide application - suitable for heavy-duty anti-corrosion scenarios such as ship ballast tanks, industrial floors, and steel structure corrosion protection, and is especially irreplaceable in the food / pharmaceutical fields with strict environmental protection requirements.

[0003] However, the curing speed and salt spray resistance of existing waterborne epoxy resin coatings still have room for improvement. Summary of the Invention

[0004] Based on this, it is necessary to provide a water-based epoxy resin coating to address the technical problems of insufficient curing speed and salt spray resistance of existing water-based epoxy resin coatings.

[0005] A waterborne epoxy resin coating comprises a component A and a component B. Component A comprises the following components in parts by mass: 60-80 parts of a 50% modified waterborne epoxy resin emulsion, 5-15 parts of deionized water, 0.5-1 parts of a wetting and dispersing agent, 0.2-0.8 parts of a defoaming agent, 5-10 parts of modified zinc phosphate, 3-5 parts of an ion exchange anti-rust pigment, 4-6 parts of sericite powder, 3-5 parts of glass flakes, 5-10 parts of precipitated barium sulfate, 1-5 parts of nano-silica, 0.5-1 parts of a rheological additive, 1-2 parts of a modified organic bentonite slurry, 0.1-0.3 parts of a pH adjuster (AMP-95), and 0.2-0.8 parts of a flash rust inhibitor.

[0006] A 50% modified waterborne epoxy resin emulsion is prepared by the following method: bisphenol A epoxy resin is compounded with a small amount of bisphenol F epoxy resin, and a flexible hydrophilic segment of polyethylene glycol (PEG, MW = 600-1000) is chemically grafted onto the epoxy resin molecular chain to obtain a modified epoxy resin, with the degree of modification controlled at 5-8wt%. Subsequently, the modified epoxy resin is heated to 60-65°C, and deionized water preheated to 55-60°C is slowly added dropwise using a high-efficiency homogenizer under medium-speed stirring. A reverse phase inversion emulsification method is used to first form a W / O emulsion, and then water is added to invert the phase to form an O / W emulsion. The final solid content is controlled at 50±2%, and the pH value is adjusted to 6.5-7.5 (using a small amount of AMP-95 or ammonia water).

[0007] Component B includes the following components by mass: 40-50 parts of waterborne epoxy-amine adduct, 20-30 parts of 50% modified polyamide curing agent, 5-15 parts of 60% Mannich base phenalkamine curing agent, 0.5-1.5 parts of epoxy silane coupling agent, 1-2 parts of nonionic surfactant and 15-20 parts of deionized water.

[0008] Preferably, the emulsifier is a reactive silicone modified nonionic surfactant, and the amount used is 1.5-2.5% of the total amount of the resin.

[0009] Preferably, component A comprises the following components by mass: 60-70 parts of 50% modified waterborne epoxy resin emulsion, 5-10 parts of deionized water, 0.5-0.8 parts of wetting and dispersing agent, 0.2-0.5 parts of defoaming agent, 5-8 parts of modified zinc phosphate, 3-4 parts of ion exchange anti-rust pigment, 4-5 parts of sericite powder, 3-4 parts of glass flakes, 5-8 parts of precipitated barium sulfate, 1-2 parts of nano-silica, 0.5-0.6 parts of rheological additive, 1-1.5 The invention discloses a novel epoxy-amine curing agent comprising: a modified organic bentonite slurry, 0.1-0.2 parts of a pH regulator (AMP-95) and 0.2-0.5 parts of a flash rust inhibitor; component B comprises the following components in parts by mass: 40-45 parts of a water-based epoxy-amine adduct, 20-25 parts of a 50% modified polyamide curing agent, 5-10 parts of a 60% Mannich base phenalkamine curing agent, 0.5-1 parts of an epoxy silane coupling agent, 1-1.5 parts of a nonionic surfactant and 15-17.5 parts of deionized water.

[0010] Preferably, component A comprises the following components by mass: 70-80 parts of 50% modified waterborne epoxy resin emulsion, 10-15 parts of deionized water, 0.8-1 parts of wetting and dispersing agent, 0.5-0.8 parts of defoaming agent, 8-10 parts of modified zinc phosphate, 4-5 parts of ion exchange anti-rust pigment, 5-6 parts of sericite powder, 4-5 parts of glass flakes, 8-10 parts of precipitated barium sulfate, 2-5 parts of nano-silica, 0.6-1 parts of rheological additive, 1.5-2 parts of The invention discloses a novel composite material comprising a modified organic bentonite slurry, 0.1-0.3 parts of a pH regulator (AMP-95) and 0.5-0.8 parts of a flash rust inhibitor; component B comprises the following components by mass: 45-50 parts of a water-based epoxy-amine adduct, 25-30 parts of a 50% modified polyamide curing agent, 10-15 parts of a 60% Mannich base phenalkamine curing agent, 1-1.5 parts of an epoxy silane coupling agent, 1.5-2 parts of a nonionic surfactant and 17.5-20 parts of deionized water.

[0011] Preferably, component A comprises the following components in parts by mass: 60 parts of 50% modified waterborne epoxy resin emulsion, 5 parts of deionized water, 0.5 parts of wetting and dispersing agent, 0.2 parts of defoaming agent, 5 parts of modified zinc phosphate, 3 parts of ion exchange anti-rust pigment, 4 parts of sericite powder, 3 parts of glass flakes, 5 parts of precipitated barium sulfate, 1 part of nano-silica, 0.5 parts of rheological additive, 1 part of modified organic bentonite slurry, 0.1 parts of pH regulator (AMP-95) and 0.2 parts of flash rust inhibitor; component B comprises the following components in parts by mass: 40 parts of waterborne epoxy-amine adduct, 20 parts of 50% modified polyamide curing agent, 5 parts of 60% Mannich base phenolaldehyde amine curing agent, 0.5 parts of epoxy silane coupling agent, 1 part of non-ionic surfactant and 15 parts of deionized water.

[0012] Preferably, component A comprises the following components in parts by mass: 70 parts of 50% modified waterborne epoxy resin emulsion, 10 parts of deionized water, 0.8 parts of wetting and dispersing agent, 0.5 parts of defoaming agent, 8 parts of modified zinc phosphate, 4 parts of ion exchange anti-rust pigment, 5 parts of sericite powder, 4 parts of glass flakes, 8 parts of precipitated barium sulfate, 2 parts of nano-silica, 0.6 parts of rheological additive, 1.5 parts of modified organic bentonite slurry, 0.2 parts of pH regulator (AMP-95) and 0.5 parts of flash rust inhibitor; component B comprises the following components in parts by mass: 45 parts of waterborne epoxy-amine adduct, 25 parts of 50% modified polyamide curing agent, 10 parts of 60% Mannich base phenolaldehyde amine curing agent, 1 part of epoxy silane coupling agent, 1.5 parts of non-ionic surfactant and 17.5 parts of deionized water.

[0013] Preferably, component A comprises the following components in parts by mass: 80 parts of 50% modified waterborne epoxy resin emulsion, 15 parts of deionized water, 1 part of wetting and dispersing agent, 0.8 parts of defoaming agent, 10 parts of modified zinc phosphate, 5 parts of ion exchange anti-rust pigment, 6 parts of sericite powder, 5 parts of glass flakes, 10 parts of precipitated barium sulfate, 5 parts of nano-silica, 1 part of rheological additive, 2 parts of modified organic bentonite slurry, 0.3 parts of pH regulator (AMP-95) and 0.8 parts of flash rust inhibitor; component B comprises the following components in parts by mass: 50 parts of waterborne epoxy-amine adduct, 30 parts of 50% modified polyamide curing agent, 15 parts of 60% Mannich base phenolaldehyde amine curing agent, 1.5 parts of epoxy silane coupling agent, 2 parts of non-ionic surfactant and 20 parts of deionized water.

[0014] A method for preparing a water-based epoxy resin coating comprises the following steps: A1. Prepare component A; A2, prepare component B; A3. Prepare the paint before construction.

[0015] In one embodiment, the above step A1 includes the following steps: A11. Add water-based epoxy resin emulsion and deionized water to a dispersion tank and stir at medium speed (500-800 rpm); A12. Add wetting and dispersing agent and first-stage defoamer and stir for 5 minutes; A13. Slowly add all pigments and fillers (zinc phosphate, ion exchange pigment, sericite, glass flakes, barium sulfate, nano-silica) in sequence, taking care to avoid dust. After adding, increase the speed to 1500-2000 rpm and disperse at high speed for 20-30 minutes until the fineness is ≤50μm. A14. Reduce the speed to 800-1000 rpm, add the second stage defoamer, flash rust inhibitor, and pH adjuster, and stir for 10 minutes; A15. Slowly add the rheological additive (HEUR) and the pre-prepared modified bentonite slurry, adjusting the speed to ensure uniform dispersion and avoid excessive shearing. A16. Test the viscosity, pH and fineness, filter and package after passing the test.

[0016] In one embodiment, the above step A2 includes the following steps: A21. Add waterborne epoxy-amine adduct, modified polyamide curing agent, and Mannich base phenalkamine curing agent to a container and stir at medium speed to mix evenly. A22, add epoxy silane coupling agent and nonionic surfactant, continue stirring for 15 minutes; A23, slowly add deionized water to adjust to the target viscosity and solid content; A24, test viscosity, filter and package.

[0017] In one embodiment, the above step A3 includes the following steps: A31. Before construction, stir component A thoroughly; A32. Add component B to component A in the ratio (A:B=4:1); A33. Use a mechanical stirrer to mix thoroughly for 3-5 minutes to ensure uniformity; A34. Add appropriate amount of deionized water (usually 5-15%) to adjust to the construction viscosity; A35. Pot life after mixing: Design target ≥ 2 hours at 25°C (meeting conventional construction requirements); A36. Use brush, roller or airless spray for construction.

[0018] A heavy-duty anti-corrosion coating for a ship ballast tank using a water-based epoxy resin coating, the construction process of which comprises the following steps: B1. Sandblast the pre-set application surface to Sa2.5 level; B2. Spray epoxy zinc-rich primer with a film thickness of 40 μm; B3, wet-on-wet spraying of water-based epoxy resin paint, with a paint film thickness of 200μm; S4, curing at 25℃ for 72h; S5, polyurethane topcoat finishing, paint film thickness is 50μm.

[0019] In summary, the waterborne epoxy resin coating disclosed in the present invention improves emulsion stability by grafting polyethylene glycol hydrophilic segments onto a bisphenol A / F hybrid epoxy emulsion. Furthermore, a shielding layer is formed by adding a 30% silane coupling agent with a diameter-to-thickness ratio of 300:1 to modify glass flakes, thereby enhancing corrosion resistance. Furthermore, a Mannich base-modified phenalkamine + autocatalytic polyamide composite curing agent is used to achieve low-temperature curing at 5°C. Specifically: (1) Fast drying: The composite curing agent system (especially Mannich base and self-catalytic polyamide) significantly shortens the surface drying and actual drying time, improving efficiency; (2) Excellent water resistance / salt spray resistance: Chemically grafted hydrophilic chains, reactive emulsifiers, high-efficiency flake filler shielding, and high cross-linking density work together to significantly improve water resistance; (3) Good low-temperature curing: The self-catalytic effect of the modified polyamide and the high activity of the Mannich base enable it to cure well at 5-10°C; (4) High storage stability: Chemically modified resin, reactive / stable emulsifier, and optimized rheological system ensure long-term storage stability of components A and B; (5) Strong adhesion and mechanical properties: Silane coupling agent, polar groups and optimized resin / curing agent system ensure good adhesion to a variety of substrates and excellent hardness and wear resistance. DETAILED DESCRIPTION

[0020] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Example 1

[0021] The present invention discloses a waterborne epoxy resin coating, which comprises a component A and a component B. The component A comprises the following components in parts by mass: 60-80 parts of a 50% modified waterborne epoxy resin emulsion, 5-15 parts of deionized water, 0.5-1 parts of a wetting and dispersing agent, 0.2-0.8 parts of a defoaming agent, 5-10 parts of modified zinc phosphate, 3-5 parts of an ion exchange anti-rust pigment, 4-6 parts of sericite powder, 3-5 parts of glass flakes, 5-10 parts of precipitated barium sulfate, 1-5 parts of nano-silica, 0.5-1 parts of a rheological additive, 1-2 parts of a modified organic bentonite slurry, 0.1-0.3 parts of a pH adjuster (AMP-95), and 0.2-0.8 parts of a flash rust inhibitor. Among them, the wetting and dispersing agent adopts high molecular weight block copolymer type to ensure that the pigments and fillers are fully dispersed and stable; the defoaming agent adopts polyether-siloxane copolymer to ensure high efficiency and not easy to produce shrinkage holes; the rheological additive adopts non-ionic polyurethane thickener and a small amount of modified organic bentonite to provide good construction rheology and anti-sagging properties, while maintaining high shear viscosity for easy spraying.

[0022] Specifically, a 50% modified waterborne epoxy resin emulsion is prepared by the following method: bisphenol A epoxy resin is compounded with a small amount of bisphenol F epoxy resin, and polyethylene glycol (PEG, MW = 600-1000) flexible hydrophilic segments are chemically grafted onto the epoxy resin molecular chains to obtain a modified epoxy resin with a degree of modification controlled at 5-8 wt%. Subsequently, the modified epoxy resin is heated to 60-65°C and, using a high-efficiency homogenizer, deionized water preheated to 55-60°C is slowly added dropwise under medium-speed stirring. A reverse phase inversion emulsification method is used to first form a W / O emulsion, followed by the addition of water to form an O / W emulsion. The final solids content is controlled at 50±2%, and the pH is adjusted to 6.5-7.5 (using a small amount of AMP-95 or ammonia). More specifically, a reactive silicone-modified nonionic surfactant is used as the emulsifier, with an amount of 1.5-2.5% of the total resin. Bisphenol F provides better flexibility and lower viscosity (favorable for emulsification), while bisphenol A provides higher rigidity and chemical resistance. At the same time, through hydrophilic modification, it is more stable than traditional external surfactants, reduces migration, and significantly improves water resistance.

[0023] Component B includes the following components by mass: 40-50 parts of waterborne epoxy-amine adduct, 20-30 parts of 50% modified polyamide curing agent, 5-15 parts of 60% Mannich base phenalkamine curing agent, 0.5-1.5 parts of epoxy silane coupling agent, 1-2 parts of nonionic surfactant and 15-20 parts of deionized water. Among them, water-based epoxy-amine adducts provide the main cross-linking reaction and good hardness and adhesion, with an amine hydrogen equivalent of approximately 200-250; the compounded modified polyamide curing agent, selecting a low-viscosity, low-molecular-weight, self-catalytic modified polyamide resin, can provide excellent flexibility, adhesion and significant low-temperature curing promotion effect, especially in humid environments, with an amine hydrogen equivalent of approximately 350-450; adding a Mannich base-modified phenolic amine curing agent, this curing agent has extremely high reactivity and can significantly accelerate surface drying and early hardness development, and give the paint film excellent chemical resistance and excellent water resistance brought by high cross-linking density; the entire curing agent system needs to be water-based modified by non-ionic surfactants such as alkylphenol polyoxyethylene ether substitutes or carboxylic acid salts to ensure good compatibility between component B and component A emulsion; adding a small amount of epoxy silane coupling agent can enhance adhesion to the substrate and paint film density.

[0024] In actual application, the mixing ratio of component A to component B is 4:1.

[0025] Based on the above ratio of component A and component B, the present invention also discloses a method for preparing a water-based epoxy resin coating, which comprises the following steps: A1. Prepare component A; A2, prepare component B; A3. Prepare the paint before construction.

[0026] Specifically, the above step A1 includes the following steps: A11. Add water-based epoxy resin emulsion and deionized water to a dispersion tank and stir at medium speed (500-800 rpm); A12. Add wetting and dispersing agent and first-stage defoamer and stir for 5 minutes; A13. Slowly add all pigments and fillers (zinc phosphate, ion exchange pigment, sericite, glass flakes, barium sulfate, nano-silica) in sequence, taking care to avoid dust. After adding, increase the speed to 1500-2000 rpm and disperse at high speed for 20-30 minutes until the fineness is ≤50μm. A14. Reduce the speed to 800-1000 rpm, add the second stage defoamer, flash rust inhibitor, and pH adjuster, and stir for 10 minutes; A15. Slowly add the rheological additive (HEUR) and the pre-prepared modified bentonite slurry, adjusting the speed to ensure uniform dispersion and avoid excessive shearing. A16. Test the viscosity, pH and fineness, filter and package after passing the test.

[0027] Specifically, the above step A2 includes the following steps: A21. Add waterborne epoxy-amine adduct, modified polyamide curing agent, and Mannich base phenalkamine curing agent to a container and stir at medium speed to mix evenly. A22, add epoxy silane coupling agent and nonionic surfactant, continue stirring for 15 minutes; A23, slowly add deionized water to adjust to the target viscosity and solid content; A24, test viscosity, filter and package.

[0028] Specifically, the above step A3 includes the following steps: A31. Before construction, stir component A thoroughly; A32. Add component B to component A in the ratio (A:B=4:1); A33. Use a mechanical stirrer to mix thoroughly for 3-5 minutes to ensure uniformity; A34. Add appropriate amount of deionized water (usually 5-15%) to adjust to the construction viscosity; A35. Pot life after mixing: Design target ≥ 2 hours at 25°C (meeting conventional construction requirements); A36. Use brush, roller or airless spray for construction.

[0029] The present invention also discloses a heavy-duty anti-corrosion coating for a ship ballast tank using a water-based epoxy resin coating. The construction process of the heavy-duty anti-corrosion coating for a ship ballast tank comprises the following steps: B1. Sandblast the pre-set application surface to Sa2.5 level; B2. Spray epoxy zinc-rich primer with a film thickness of 40 μm; B3, wet-on-wet spraying of water-based epoxy resin paint, with a paint film thickness of 200μm; S4, curing at 25℃ for 72h; S5, polyurethane topcoat finishing, paint film thickness is 50μm.

[0030] The embodiments of the present invention will be described in detail below with reference to a number of examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. For experimental methods in the following examples where specific conditions are not specified, reference is made to the guidance provided in the present invention, and may also be made according to experimental manuals or conventional conditions in the art, or according to conditions recommended by the manufacturer, or with reference to experimental methods known in the art. Example 2

[0031] Different from Example 1, component A in this embodiment includes the following components in parts by mass: 60-70 parts of 50% modified water-based epoxy resin emulsion, 5-10 parts of deionized water, 0.5-0.8 parts of wetting and dispersing agent, 0.2-0.5 parts of defoaming agent, 5-8 parts of modified zinc phosphate, 3-4 parts of ion exchange anti-rust pigment, 4-5 parts of sericite powder, 3-4 parts of glass flakes, 5-8 parts of precipitated barium sulfate, 1-2 parts of nano-silica, 0.5-0.6 parts of rheological additive, 1-1.5 parts of modified organic bentonite slurry, 0.1-0.2 parts of pH adjuster (AMP-95) and 0.2-0.5 parts of flash rust inhibitor.

[0032] Component B includes the following components by mass: 40-45 parts of water-based epoxy-amine adduct, 20-25 parts of 50% modified polyamide curing agent, 5-10 parts of 60% Mannich base phenalkamine curing agent, 0.5-1 part of epoxy silane coupling agent, 1-1.5 parts of non-ionic surfactant and 15-17.5 parts of deionized water. Example 3

[0033] Different from Example 1, component A in this embodiment includes the following components in parts by mass: 70-80 parts of 50% modified water-based epoxy resin emulsion, 10-15 parts of deionized water, 0.8-1 parts of wetting and dispersing agent, 0.5-0.8 parts of defoaming agent, 8-10 parts of modified zinc phosphate, 4-5 parts of ion exchange anti-rust pigment, 5-6 parts of sericite powder, 4-5 parts of glass flakes, 8-10 parts of precipitated barium sulfate, 2-5 parts of nano-silica, 0.6-1 parts of rheological additive, 1.5-2 parts of modified organic bentonite slurry, 0.1-0.3 parts of pH adjuster (AMP-95) and 0.5-0.8 parts of flash rust inhibitor.

[0034] Component B includes the following components by mass: 45-50 parts of water-based epoxy-amine adduct, 25-30 parts of 50% modified polyamide curing agent, 10-15 parts of 60% Mannich base phenalkamine curing agent, 1-1.5 parts of epoxy silane coupling agent, 1.5-2 parts of non-ionic surfactant and 17.5-20 parts of deionized water. Example 4

[0035] Different from Example 1, component A in this embodiment includes the following components in parts by mass: 60 parts of 50% modified water-based epoxy resin emulsion, 5 parts of deionized water, 0.5 parts of wetting and dispersing agent, 0.2 parts of defoaming agent, 5 parts of modified zinc phosphate, 3 parts of ion exchange anti-rust pigment, 4 parts of sericite powder, 3 parts of glass flakes, 5 parts of precipitated barium sulfate, 1 part of nano-silica, 0.5 parts of rheological additive, 1 part of modified organic bentonite slurry, 0.1 parts of pH adjuster (AMP-95) and 0.2 parts of flash rust inhibitor.

[0036] Component B includes the following components by mass: 40 parts of waterborne epoxy-amine adduct, 20 parts of 50% modified polyamide curing agent, 5 parts of 60% Mannich base phenalkamine curing agent, 0.5 parts of epoxy silane coupling agent, 1 part of nonionic surfactant and 15 parts of deionized water. Example 5

[0037] Different from Example 1, component A in this embodiment includes the following components in parts by mass: 70 parts of 50% modified water-based epoxy resin emulsion, 10 parts of deionized water, 0.8 parts of wetting and dispersing agent, 0.5 parts of defoaming agent, 8 parts of modified zinc phosphate, 4 parts of ion exchange anti-rust pigment, 5 parts of sericite powder, 4 parts of glass flakes, 8 parts of precipitated barium sulfate, 2 parts of nano-silica, 0.6 parts of rheological additive, 1.5 parts of modified organic bentonite slurry, 0.2 parts of pH adjuster (AMP-95) and 0.5 parts of flash rust inhibitor.

[0038] Component B includes the following components by mass: 45 parts of waterborne epoxy-amine adduct, 25 parts of 50% modified polyamide curing agent, 10 parts of 60% Mannich base phenalkamine curing agent, 1 part of epoxy silane coupling agent, 1.5 parts of nonionic surfactant and 17.5 parts of deionized water. Example 6

[0039] Different from Example 1, component A in this embodiment includes the following components in parts by mass: 80 parts of 50% modified water-based epoxy resin emulsion, 15 parts of deionized water, 1 part of wetting and dispersing agent, 0.8 parts of defoaming agent, 10 parts of modified zinc phosphate, 5 parts of ion exchange anti-rust pigment, 6 parts of sericite powder, 5 parts of glass flakes, 10 parts of precipitated barium sulfate, 5 parts of nano-silica, 1 part of rheological additive, 2 parts of modified organic bentonite slurry, 0.3 parts of pH adjuster (AMP-95) and 0.8 parts of flash rust inhibitor.

[0040] Component B includes the following components by mass: 50 parts of waterborne epoxy-amine adduct, 30 parts of 50% modified polyamide curing agent, 15 parts of 60% Mannich base phenalkamine curing agent, 1.5 parts of epoxy silane coupling agent, 2 parts of nonionic surfactant and 20 parts of deionized water.

[0041] Based on the scheme of Example 5, the performance of the waterborne epoxy resin coating of the present invention was verified, and the results are shown in Table 1 and Table 6: 1. Basic Performance Verification Table 1

[0042] 2. Verification of environmental corrosion resistance 1. Salt spray test Table 2

[0043] 2. Resistance to medium immersion Table 3

[0044] 3. Verification of long-term protection performance 1. Electrochemical Impedance Spectroscopy Table 4

[0045] 2. Accelerated aging test Table 5

[0046] 4. Construction Practicality Verification Table 6

[0047] In summary, the waterborne epoxy resin coating disclosed in the present invention improves emulsion stability by grafting polyethylene glycol hydrophilic segments onto a bisphenol A / F hybrid epoxy emulsion. Furthermore, a shielding layer is formed by adding a 30% silane coupling agent with a diameter-to-thickness ratio of 300:1 to modify glass flakes, thereby enhancing corrosion resistance. Furthermore, a Mannich base-modified phenalkamine + autocatalytic polyamide composite curing agent is used to achieve low-temperature curing at 5°C. Specifically: (1) Fast drying: The composite curing agent system (especially Mannich base and self-catalytic polyamide) significantly shortens the surface drying and actual drying time, improving efficiency; (2) Excellent water resistance / salt spray resistance: Chemically grafted hydrophilic chains, reactive emulsifiers, high-efficiency flake filler shielding, and high cross-linking density work together to significantly improve water resistance; (3) Good low-temperature curing: The self-catalytic effect of the modified polyamide and the high activity of the Mannich base enable it to cure well at 5-10°C; (4) High storage stability: Chemically modified resin, reactive / stable emulsifier, and optimized rheological system ensure long-term storage stability of components A and B; (5) Strong adhesion and mechanical properties: Silane coupling agent, polar groups and optimized resin / curing agent system ensure good adhesion to a variety of substrates and excellent hardness and wear resistance.

[0048] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A water-based epoxy resin coating, characterized in that: include: Component A and component B, component A comprises the following components in parts by mass: 60-80 parts of 50% modified waterborne epoxy resin emulsion, 5-15 parts of deionized water, 0.5-1 parts of wetting and dispersing agent, 0.2-0.8 parts of defoaming agent, 5-10 parts of modified zinc phosphate, 3-5 parts of ion exchange anti-rust pigment, 4-6 parts of sericite powder, 3-5 parts of glass flakes, 5-10 parts of precipitated barium sulfate, 1-5 parts of nano-silica, 0.5-1 parts of rheological additive, 1-2 parts of modified organic bentonite slurry, 0.1-0.3 parts of pH adjuster and 0.2-0.8 parts of flash rust inhibitor; A 50% modified waterborne epoxy resin emulsion is prepared by the following method: bisphenol A epoxy resin is compounded with a small amount of bisphenol F epoxy resin, and a flexible hydrophilic segment of polyethylene glycol (PEG, MW = 600-1000) is chemically grafted onto the epoxy resin molecular chain to obtain a modified epoxy resin, with the degree of modification controlled at 5-8wt%. Subsequently, the modified epoxy resin is heated to 60-65°C, and deionized water preheated to 55-60°C is slowly added dropwise using a high-efficiency homogenizer under medium-speed stirring. A reverse phase inversion emulsification method is used to first form a W / O emulsion, and then water is added to invert the phase to form an O / W emulsion. The final solid content is controlled at 50±2%, and the pH value is adjusted to 6.5-7.

5. Component B includes the following components by mass: 40-50 parts of waterborne epoxy-amine adduct, 20-30 parts of 50% modified polyamide curing agent, 5-15 parts of 60% Mannich base phenalkamine curing agent, 0.5-1.5 parts of epoxy silane coupling agent, 1-2 parts of nonionic surfactant and 15-20 parts of deionized water.

2. The water-based epoxy resin coating according to claim 1, characterized in that Component A includes the following components by mass: 60-70 parts of 50% modified waterborne epoxy resin emulsion, 5-10 parts of deionized water, 0.5-0.8 parts of wetting and dispersing agent, 0.2-0.5 parts of defoaming agent, 5-8 parts of modified zinc phosphate, 3-4 parts of ion exchange anti-rust pigment, 4-5 parts of sericite powder, 3-4 parts of glass flakes, 5-8 parts of precipitated barium sulfate, 1-2 parts of nano-silica, 0.5-0.6 parts of rheological additive, 1-1 0.5 parts of modified organic bentonite slurry, 0.1-0.2 parts of pH adjuster and 0.2-0.5 parts of flash rust inhibitor; component B includes the following components in parts by mass: 40-45 parts of water-based epoxy-amine adduct, 20-25 parts of 50% modified polyamide curing agent, 5-10 parts of 60% Mannich base phenolaldehyde amine curing agent, 0.5-1 parts of epoxy silane coupling agent, 1-1.5 parts of non-ionic surfactant and 15-17.5 parts of deionized water.

3. The water-based epoxy resin coating according to claim 1, characterized in that: Component A includes the following components by mass: 70-80 parts of 50% modified waterborne epoxy resin emulsion, 10-15 parts of deionized water, 0.8-1 parts of wetting and dispersing agent, 0.5-0.8 parts of defoaming agent, 8-10 parts of modified zinc phosphate, 4-5 parts of ion exchange anti-rust pigment, 5-6 parts of sericite powder, 4-5 parts of glass flakes, 8-10 parts of precipitated barium sulfate, 2-5 parts of nano-silica, 0.6-1 parts of rheological additive, 1.5- 2 parts of modified organic bentonite slurry, 0.1-0.3 parts of pH adjuster and 0.5-0.8 parts of flash rust inhibitor; component B includes the following components in parts by mass: 45-50 parts of water-based epoxy-amine adduct, 25-30 parts of 50% modified polyamide curing agent, 10-15 parts of 60% Mannich base phenalkamine curing agent, 1-1.5 parts of epoxy silane coupling agent, 1.5-2 parts of non-ionic surfactant and 17.5-20 parts of deionized water.

4. The water-based epoxy resin coating according to claim 1, characterized in that: Component A includes the following components in parts by mass: 60 parts of 50% modified water-based epoxy resin emulsion, 5 parts of deionized water, 0.5 parts of wetting and dispersing agent, 0.2 parts of defoaming agent, 5 parts of modified zinc phosphate, 3 parts of ion exchange anti-rust pigment, 4 parts of sericite powder, 3 parts of glass flakes, 5 parts of precipitated barium sulfate, 1 part of nano-silica, 0.5 parts of rheological additive, 1 part of modified organic bentonite slurry, 0.1 parts of pH adjuster and 0.2 parts of flash rust inhibitor; Component B includes the following components in parts by mass: 40 parts of water-based epoxy-amine adduct, 20 parts of 50% modified polyamide curing agent, 5 parts of 60% Mannich base phenolaldehyde amine curing agent, 0.5 parts of epoxy silane coupling agent, 1 part of non-ionic surfactant and 15 parts of deionized water.

5. The water-based epoxy resin coating according to claim 1, characterized in that: Component A includes the following components in parts by mass: 70 parts of 50% modified water-based epoxy resin emulsion, 10 parts of deionized water, 0.8 parts of wetting and dispersing agent, 0.5 parts of defoaming agent, 8 parts of modified zinc phosphate, 4 parts of ion exchange anti-rust pigment, 5 parts of sericite powder, 4 parts of glass flakes, 8 parts of precipitated barium sulfate, 2 parts of nano-silica, 0.6 parts of rheological additive, 1.5 parts of modified organic bentonite slurry, 0.2 parts of pH adjuster and 0.5 parts of flash rust inhibitor; Component B includes the following components in parts by mass: 45 parts of water-based epoxy-amine adduct, 25 parts of 50% modified polyamide curing agent, 10 parts of 60% Mannich base phenolaldehyde amine curing agent, 1 part of epoxy silane coupling agent, 1.5 parts of non-ionic surfactant and 17.5 parts of deionized water.

6. A method for preparing the waterborne epoxy resin coating according to any one of claims 1 to 5, comprising the following steps: A1. Prepare component A; A2, prepare component B; A3. Prepare the paint before construction.

7. The water-based epoxy resin coating according to claim 6, characterized in that: The above-mentioned step A1 includes the following steps: A11. Add water-based epoxy resin emulsion and deionized water to a dispersion tank and stir at medium speed (500-800 rpm); A12. Add wetting and dispersing agent and first-stage defoamer and stir for 5 minutes; A13. Slowly add all pigments and fillers (zinc phosphate, ion exchange pigment, sericite, glass flakes, barium sulfate, nano-silica) in sequence, taking care to avoid dust. After adding, increase the speed to 1500-2000 rpm and disperse at high speed for 20-30 minutes until the fineness is ≤50μm. A14. Reduce the speed to 800-1000 rpm, add the second stage defoamer, flash rust inhibitor, and pH adjuster, and stir for 10 minutes; A15. Slowly add the rheological additive (HEUR) and the pre-prepared modified bentonite slurry, adjusting the speed to ensure uniform dispersion and avoid excessive shearing. A16. Test the viscosity, pH and fineness, filter and package after passing the test.

8. The water-based epoxy resin coating according to claim 6, characterized in that: The above-mentioned step A2 includes the following steps: A21. Add waterborne epoxy-amine adduct, modified polyamide curing agent, and Mannich base phenalkamine curing agent to a container and stir at medium speed to mix evenly. A22, add epoxy silane coupling agent and nonionic surfactant, continue stirring for 15 minutes; A23, slowly add deionized water to adjust to the target viscosity and solid content; A24, test viscosity, filter and package.

9. The water-based epoxy resin coating according to claim 6, characterized in that: The above-mentioned step A3 includes the following steps: A31. Before construction, stir component A thoroughly; A32. Add component B to component A in the ratio (A:B=4:1); A33. Use a mechanical stirrer to mix thoroughly for 3-5 minutes to ensure uniformity; A34. Add appropriate amount of deionized water (usually 5-15%) to adjust to the construction viscosity; A35. Pot life after mixing: Design target ≥ 2 hours at 25°C (meeting conventional construction requirements); A36. Use brush, roller or airless spray for construction.

10. A heavy-duty anti-corrosion coating for a ship ballast tank using the waterborne epoxy resin coating according to any one of claims 1 to 5, wherein the construction process of the heavy-duty anti-corrosion coating for a ship ballast tank comprises the following steps: B1. Sandblast the pre-set application surface to Sa2.5 level; B2. Spray epoxy zinc-rich primer with a film thickness of 40 μm; B3, wet-on-wet spraying of water-based epoxy resin paint, with a paint film thickness of 200μm; S4, curing at 25℃ for 72h; S5, polyurethane topcoat finishing, paint film thickness is 50μm.

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