Water-based environment-friendly two-component epoxy resin coating and preparation method thereof

Abstract

The present application relates to the technical fields of epoxy resin paint, and especially relates to a water-based environment-friendly two-component epoxy resin paint and a preparation method thereof.The water-based environment-friendly two-component epoxy resin paint comprises a component A and a component B, wherein the mass ratio of the component A to the component B is 10:1-5;the component A comprises, by mass fraction, 30-40 parts of a core-shell type epoxy resin emulsion, 1-2 parts of an organic alcohol amine, 30-40 parts of pretreated zinc powder, 0.1-0.5 parts of a polycarboxylate type dispersant, 1-2 parts of an inhibitor, 1-2 parts of a thixotropic agent, 1-2 parts of a cosolvent and 1-2 parts of a defoaming agent;the component B comprises, by mass fraction, 50-60 parts of a polyether amine, 0.5-1 parts of a curing accelerator, 1-5 parts of a hyperbranched polyester dispersant, 5-10 parts of a cosolvent and 20-40 parts of water.The present application has strong storage stability, and the obtained coating has excellent impact strength and long-term corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin coating technology, and in particular to a water-based environmentally friendly two-component epoxy resin coating and its preparation method. Background Technology

[0002] While traditional epoxy resin coatings offer excellent chemical resistance in heavy-duty corrosion protection, their impact resistance and long-term storage stability are significantly compromised. In the harsh environments of marine engineering, coatings frequently crack and peel due to mechanical impacts or stress deformation, exposing the substrate to corrosive media and drastically shortening the protective lifespan. Current technologies often add toughening agents to improve impact resistance, but these substances tend to reduce coating hardness and exacerbate phase separation, leading to decreased corrosion resistance. Furthermore, conventional waterborne epoxy systems suffer from poor resin-hardener compatibility, making them prone to delamination or pre-curing reactions during storage, severely limiting the coating's application window.

[0003] Regarding corrosion resistance, traditional zinc-rich coatings provide cathodic protection through the sacrificial anode mechanism of zinc powder. However, the bonding force between zinc powder and resin is insufficient, and the accumulation of corrosion products easily leads to blistering and peeling of the coating. Especially in humid, hot, and salt spray environments, the micropores inside the coating can easily form electrolytic channels, accelerating pitting corrosion of the metal substrate. Currently, commercially available water-based epoxy coatings often use three-component packaging technology to delay the reaction between zinc powder and water. However, the on-site mixing uniformity of zinc powder is poor, and moisture is not completely isolated during storage. The zinc powder will still slowly react to form basic zinc carbonate, resulting in increased coating viscosity, deteriorated leveling properties during application, and a tendency for porosity defects in the coating film.

[0004] In existing waterborne epoxy coating systems, the insufficient cross-linking density of the cured resin network leads to weak coating impermeability. Especially under alternating temperature conditions, the difference in thermal expansion coefficients between the resin and fillers causes microcrack propagation, allowing corrosive media to rapidly penetrate to the substrate surface along these cracks. Furthermore, traditional coatings require the addition of large amounts of organic corrosion inhibitors to improve storage stability. These inhibitors tend to migrate to the coating surface, forming microscopic hydrophilic regions, which exacerbates the coating's water absorption and swelling problem, severely impacting long-term corrosion resistance. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a water-based, environmentally friendly two-component epoxy resin coating and its preparation method.

[0006] A water-based, environmentally friendly two-component epoxy resin coating comprises component A and component B, wherein the mass ratio of component A to component B is 10:1-5. Component A comprises, by mass, 30-40 parts of core-shell epoxy resin emulsion, 1-2 parts of organic alcohol amine, 30-40 parts of pretreated zinc powder, 0.1-0.5 parts of polycarboxylate dispersant, 1-2 parts of corrosion inhibitor, 1-2 parts of thixotropic agent, 1-2 parts of cosolvent, and 1-2 parts of defoamer. Component B comprises, by mass, 50-60 parts of polyether amine, 0.5-1 part of curing accelerator, 1-5 parts of hyperbranched polyester dispersant, 5-10 parts of cosolvent, and 20-40 parts of water.

[0007] Preferably, the corrosion inhibitor comprises zinc phosphate, sodium molybdate, and cerium nitrate, wherein the mass ratio of zinc phosphate, sodium molybdate, and cerium nitrate is 1-5:0.5-1:0.1-1.

[0008] Preferably, the organic alcohol amine is triethanolamine.

[0009] Preferably, the polycarboxylate dispersant is BYK-190 dispersant.

[0010] Preferably, the thixotropic agent is fumed silica.

[0011] Preferably, the co-solvent is propylene glycol methyl ether.

[0012] Preferably, the curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

[0013] Preferably, the core-shell epoxy resin emulsion is prepared by the following steps: under nitrogen protection, polyester polyol, isophorone diisocyanate, and dimethylolpropionic acid are mixed and stirred at 70-80°C for 1-3 hours, cooled to 50-60°C, and triethylamine and water are added and stirred for 10-20 minutes to obtain a prepolymer; glycidyl acrylate, methyl methacrylate, emulsifier, and water are mixed and stirred at 40-50°C for 10-20 minutes to obtain a composite emulsion; a portion of the composite emulsion and initiator are added to the prepolymer and stirred at 75-82°C for 1-2 hours; the remaining composite emulsion and initiator are added dropwise while stirring, and stirred at 85-90°C for 2-4 hours; cooled to room temperature, the pH of the system is adjusted to 8.2-8.6, and then filtered.

[0014] More preferably, the mass ratio of polyester polyol, isophorone diisocyanate, dimethylolpropionic acid, triethylamine, glycidyl acrylate, methyl methacrylate, emulsifier, and initiator is 20-30:8-12:2-4:1-3:10-20:5-15:1-2:0.4-1.2.

[0015] More preferably, the hydroxyl value of the polyester polyol is 110-130 mgKOH / g.

[0016] More preferably, the initiator is persulfate or ammonium persulfate.

[0017] More preferably, the composite emulsion and the initiator are added sequentially, with the mass ratio of the composite emulsion added first to the composite emulsion added later being 20-30:70-80, and the mass ratio of the initiator added first to the initiator added later being 0.1-0.2:0.3-1.

[0018] Preferably, the pretreated zinc powder is prepared by the following steps: the zinc powder is acid-washed and activated with dilute phosphoric acid, added to an ethanol aqueous solution, γ-aminopropyltriethoxysilane is added, refluxed and stirred at 70-80℃ for 2-4h, fumed silica is added and stirring is continued for 10-30min, centrifuged, filtered, washed, heat-treated at 105-112℃ for 1-2h, cooled, and pulverized to D50≤5μm.

[0019] More preferably, the mass ratio of zinc powder, γ-aminopropyltriethoxysilane, and fumed silica is 30-40:1-3:1-5.

[0020] The preparation method of the above-mentioned water-based environmentally friendly two-component epoxy resin coating includes the following steps:

[0021] S1. Premix the core-shell epoxy resin emulsion and organic alcohol amine, add pretreated zinc powder and ultrasonically treat for 10-20 min, add polycarboxylate dispersant, corrosion inhibitor, thixotropic agent, cosolvent and defoamer and disperse at high speed for 10-20 min, filter to obtain component A;

[0022] S2. Stir the polyetheramine, curing accelerator, and hyperbranched polyester dispersant for 10-20 minutes, cool to room temperature, add co-solvent and water, and sonicate for 20-30 minutes to obtain component B.

[0023] The above-mentioned water-based environmentally friendly two-component epoxy resin coating is applied by the following steps: mixing component A and component B evenly, letting stand for 20-40 minutes, and then spraying under high pressure to a total thickness of 120-150 μm.

[0024] Preferably, the pressure of high-pressure spraying is 15-20 MPa, and the spray gun moving speed is 0.8-1.2 m / s.

[0025] Beneficial effects;

[0026] The core-shell epoxy resin emulsion used in this invention uses polyurethane as the elastic core, which can not only absorb impact energy, but also the acrylic epoxy shell can provide rigid support. When the coating is impacted, the elastic phase dissipates energy through the slippage of the molecular chains, and the rigid phase inhibits crack propagation, resulting in excellent impact resistance of the coating.

[0027] This invention further activates zinc powder by acid washing, causing its surface hydroxyl groups to combine with the hydrolysis products of γ-aminopropyltriethoxysilane to form Si-O-Zn covalent bonds. Meanwhile, fumed silica is loaded on the surface to form a steric hindrance protective layer to prevent sedimentation. The resulting pretreated zinc powder can undergo a ring-opening reaction with the epoxy groups in the core-shell epoxy resin emulsion, thereby achieving synergistic optimization of long-term corrosion protection and impact resistance. At the same time, the pretreated zinc powder can be compounded with polycarboxylate dispersants to improve the dispersion stability of zinc powder through electrostatic repulsion, effectively preventing secondary agglomeration and greatly enhancing storage stability, further reducing the occurrence of agglomeration or stratification.

[0028] This invention significantly enhances the corrosion resistance of zinc powder through pretreatment and the use of corrosion inhibitors. Specifically, zinc phosphate reacts with cerium nitrate in areas of coating damage (such as localized acidic environments) to generate CeP. Precipitation fills micropores and blocks C Penetration reduces the corrosion current density, while rare earth ions preferentially occupy the micropores of the coating, blocking C The penetration path is greatly enhanced, and the corrosion resistance and stability are significantly improved. Through synergistic effects, the long-term corrosion protection capability of the coating is significantly improved. Attached Figure Description

[0029] Figure 1 The image shows a comparison of the impact resistance and flexibility of the coatings made from the two-component epoxy resin coatings obtained in Example 5 and Comparative Examples 1-2.

[0030] Figure 2 This is a comparison chart showing the adhesion of coatings made using the epoxy resin coatings obtained in Example 5 and Comparative Examples 1-2. Detailed Implementation

[0031] The present invention will be further explained below with reference to specific embodiments.

[0032] The polyester polyol was purchased from Qingdao Yutian Chemical Co., Ltd., and its brand name is POL-7112. The hyperbranched polyester dispersant is Basonol HPE 1170 B.

[0033] Example 1

[0034] A water-based, environmentally friendly two-component epoxy resin coating includes component A and component B, wherein the mass ratio of component A to component B is 10:1.

[0035] Component A comprises: 300g core-shell epoxy resin emulsion, 10g triethanolamine, 300g pretreated zinc powder, 1g BYK-190 dispersant, 10g corrosion inhibitor, 10g fumed silica, 10g propylene glycol methyl ether, and 10g TEGO-8030. The corrosion inhibitor is composed of zinc phosphate, sodium molybdate, and cerium nitrate in a mass ratio of 1:0.5:0.1.

[0036] The core-shell epoxy resin emulsion was prepared using the following steps: Under nitrogen protection, 200g of polyester polyol, 80g of isophorone diisocyanate, and 20g of dimethylolpropionic acid were added to a reaction vessel and stirred at 70℃ for 1 hour at a stirring speed of 400r / min. The temperature was then lowered to 50℃, and 10g of triethylamine and 500g of deionized water were added. The mixture was stirred at 1000r / min for 10 minutes to obtain the prepolymer. 100g of glycidyl acrylate and 50g of methylolpropionic acid were then added... Methyl acrylate, 10g sodium dodecyl sulfate, and 300g deionized water were mixed and stirred at 40℃ for 10min at a stirring speed of 1000r / min to obtain a composite emulsion. 20wt% of the composite emulsion and 1g of ammonium persulfate were added to the prepolymer and stirred at 75℃ for 1h. Under stirring, the remaining composite emulsion and 3g of ammonium persulfate were added dropwise, and the mixture was stirred at 85℃ for 2h. After cooling to room temperature, the pH of the system was adjusted to 8.2-8.6 using triethylamine, and then filtered.

[0037] The pretreated zinc powder was prepared using the following steps: 300g of zinc powder was acid-washed and activated with 1% (w / w) dilute phosphoric acid, added to 600g of 40% (w / w) ethanol aqueous solution, 10g of γ-aminopropyltriethoxysilane was added, and the mixture was refluxed and stirred at 70℃ for 2h. Then, 10g of fumed silica was added and the mixture was stirred for another 10min. The mixture was then centrifuged, filtered, washed with deionized water, heat-treated at 105℃ for 1h, cooled, and pulverized to a density of D50≤5μm.

[0038] Component B includes: 50g of polyetheramine, 0.5g of 2,4,6-tris(dimethylaminomethyl)phenol, 1g of hyperbranched polyester dispersant, 5g of propylene glycol methyl ether, and 20g of water.

[0039] The preparation method of the above-mentioned water-based environmentally friendly two-component epoxy resin coating includes the following steps:

[0040] S1. Premix the core-shell epoxy resin emulsion and triethanolamine, add pretreated zinc powder and sonicate for 10 min at a frequency of 30 kHz and a power of 400 W. Add BYK-190 dispersant, corrosion inhibitor, fumed silica, propylene glycol methyl ether, and TEGO-8030 and disperse at a speed of 1000 r / min for 10 min. Pass the mixture through an 80-mesh filter to obtain component A.

[0041] S2. Stir polyetheramine, 2,4,6-tris(dimethylaminomethyl)phenol and hyperbranched polyester dispersant for 10 min at a stirring speed of 400 r / min, cool to room temperature, add propylene glycol methyl ether and water, and sonicate for 20 min at a sonic frequency of 30 kHz and a sonic power of 400 W to obtain component B.

[0042] Example 2

[0043] A water-based, environmentally friendly two-component epoxy resin coating includes component A and component B, wherein the mass ratio of component A to component B is 10:5.

[0044] Component A comprises: 400g core-shell epoxy resin emulsion, 20g triethanolamine, 400g pretreated zinc powder, 5g BYK-190 dispersant, 20g corrosion inhibitor, 20g fumed silica, 20g propylene glycol methyl ether, and 20g TEGO-8030. The corrosion inhibitor is composed of zinc phosphate, sodium molybdate, and cerium nitrate in a mass ratio of 5:1:1.

[0045] The core-shell epoxy resin emulsion was prepared using the following steps: Under nitrogen protection, 300g of polyester polyol, 120g of isophorone diisocyanate, and 40g of dimethylolpropionic acid were added to a reaction vessel and stirred at 80℃ for 3 hours at a stirring speed of 500r / min. The temperature was then lowered to 60℃, and 30g of triethylamine and 1000g of deionized water were added. The mixture was stirred at 2000r / min for 20 minutes to obtain the prepolymer. 200g of glycidyl acrylate and 150g of methyl... Methyl acrylate, 20g sodium dodecyl sulfate, and 500g deionized water were mixed and stirred at 50℃ for 20min at a stirring speed of 2000r / min to obtain a composite emulsion. 30wt% of the composite emulsion and 2g of ammonium persulfate were added to the prepolymer and stirred at 82℃ for 2h. Under stirring, the remaining composite emulsion and 10g of ammonium persulfate were added dropwise and stirred at 90℃ for 4h. After cooling to room temperature, the pH of the system was adjusted to 8.2-8.6 using triethylamine and then filtered.

[0046] The pretreated zinc powder was prepared using the following steps: 400g of zinc powder was acid-washed and activated with 2% (w / w) dilute phosphoric acid, added to 1000g of 60% (w / w) aqueous ethanol solution, 30g of γ-aminopropyltriethoxysilane was added, and the mixture was refluxed and stirred at 80℃ for 4h. 50g of fumed silica was added and stirring was continued for 30min. The mixture was then centrifuged, filtered, washed with deionized water, heat-treated at 112℃ for 2h, cooled, and pulverized to a D50 ≤ 5μm.

[0047] Component B includes: 60g of polyetheramine, 1g of 2,4,6-tris(dimethylaminomethyl)phenol, 5g of hyperbranched polyester dispersant, 10g of propylene glycol methyl ether, and 40g of water.

[0048] The preparation method of the above-mentioned water-based environmentally friendly two-component epoxy resin coating includes the following steps:

[0049] S1. Premix the core-shell epoxy resin emulsion and triethanolamine, add pretreated zinc powder and sonicate for 20 min at a frequency of 35 kHz and a power of 500 W. Add BYK-190 dispersant, corrosion inhibitor, fumed silica, propylene glycol methyl ether, and TEGO-8030 and disperse at a speed of 2000 r / min for 20 min. Pass the mixture through an 80-mesh filter to obtain component A.

[0050] S2. Stir polyetheramine, 2,4,6-tris(dimethylaminomethyl)phenol and hyperbranched polyester dispersant for 20 min at a stirring speed of 600 r / min, cool to room temperature, add propylene glycol methyl ether and water, and sonicate for 30 min at a sonic frequency of 36 kHz and a sonic power of 500 W to obtain component B.

[0051] Example 3

[0052] A water-based, environmentally friendly two-component epoxy resin coating includes component A and component B, wherein the mass ratio of component A to component B is 10:2.

[0053] Component A comprises: 370g of core-shell epoxy resin emulsion, 13g of triethanolamine, 370g of pretreated zinc powder, 2g of BYK-190 dispersant, 18g of corrosion inhibitor, 13g of fumed silica, 18g of propylene glycol methyl ether, and 13g of TEGO-8030. The corrosion inhibitor is composed of zinc phosphate, sodium molybdate, and cerium nitrate in a mass ratio of 4:0.6:0.7.

[0054] The core-shell epoxy resin emulsion was prepared using the following steps: Under nitrogen protection, 220g of polyester polyol, 110g of isophorone diisocyanate, and 25g of dimethylolpropionic acid were added to a reaction vessel and stirred at 77℃ for 1.5h at a stirring speed of 480r / min. The mixture was then cooled to 52℃, and 25g of triethylamine and 700g of deionized water were added. The mixture was stirred at 1800r / min for 13min to obtain the prepolymer. 180g of glycidyl acrylate and 80g of methyl methacrylate were then added... Ester, 17g sodium dodecyl sulfate, and 350g deionized water were mixed and stirred at 48℃ for 12min at a stirring speed of 1700r / min to obtain a composite emulsion. 22wt% of the composite emulsion and 1.8g of ammonium persulfate were added to the prepolymer and stirred at 77℃ for 100min. Under stirring, the remaining composite emulsion and 4g of ammonium persulfate were added dropwise, and the mixture was stirred at 89℃ for 2.5h. After cooling to room temperature, the pH of the system was adjusted to 8.2-8.6 using triethylamine, and then filtered.

[0055] The pretreated zinc powder was prepared using the following steps: 330g of zinc powder was acid-washed and activated with 1.7% dilute phosphoric acid, added to 900g of 45% ethanol aqueous solution, 25g of γ-aminopropyltriethoxysilane was added, and the mixture was refluxed and stirred at 73℃ for 3.5h. 20g of fumed silica was added and stirring was continued for 25min. The mixture was centrifuged, filtered, washed with deionized water, heat-treated at 108℃ for 100min, cooled, and pulverized to D50≤5μm.

[0056] Component B includes: 52g of polyetheramine, 0.9g of 2,4,6-tris(dimethylaminomethyl)phenol, 2g of hyperbranched polyester dispersant, 9g of propylene glycol methyl ether, and 25g of water.

[0057] The preparation method of the above-mentioned water-based environmentally friendly two-component epoxy resin coating includes the following steps:

[0058] S1. Premix the core-shell epoxy resin emulsion and triethanolamine, add pretreated zinc powder and sonicate for 18 min at a frequency of 33 kHz and a power of 420 W. Add BYK-190 dispersant, corrosion inhibitor, fumed silica, propylene glycol methyl ether, and TEGO-8030 and disperse at high speed for 17 min at a speed of 1300 r / min. Pass the mixture through an 80-mesh filter to obtain component A.

[0059] S2. Stir polyetheramine, 2,4,6-tris(dimethylaminomethyl)phenol and hyperbranched polyester dispersant for 18 min at a stirring speed of 450 r / min, cool to room temperature, add propylene glycol methyl ether and water, and sonicate for 28 min at a sonic frequency of 33 kHz and a sonic power of 430 W to obtain component B.

[0060] Example 4

[0061] A water-based, environmentally friendly two-component epoxy resin coating includes component A and component B, wherein the mass ratio of component A to component B is 10:4.

[0062] Component A comprises: 330g of core-shell epoxy resin emulsion, 17g of triethanolamine, 330g of pretreated zinc powder, 4g of BYK-190 dispersant, 12g of corrosion inhibitor, 17g of fumed silica, 12g of propylene glycol methyl ether, and 17g of TEGO-8030. The corrosion inhibitor is composed of zinc phosphate, sodium molybdate, and cerium nitrate in a mass ratio of 2:0.8:0.3.

[0063] The core-shell epoxy resin emulsion was prepared using the following steps: Under nitrogen protection, 280g of polyester polyol, 90g of isophorone diisocyanate, and 35g of dimethylolpropionic acid were added to a reaction vessel and stirred at 73℃ for 2.5h at a stirring speed of 420r / min. The mixture was then cooled to 58℃, and 15g of triethylamine and 900g of deionized water were added. The mixture was stirred at 1200r / min for 17min to obtain the prepolymer. 120g of glycidyl acrylate and 120g of methacrylic acid were then added... Methyl ester, 13g sodium dodecyl sulfate, and 450g deionized water were mixed and stirred at 42℃ for 18min at a stirring speed of 1300r / min to obtain a composite emulsion. 28wt% of the composite emulsion and 1.2g of ammonium persulfate were added to the prepolymer and stirred at 80℃ for 80min. The remaining composite emulsion and 8g of ammonium persulfate were added dropwise while stirring, and the mixture was stirred at 87℃ for 3.5h. After cooling to room temperature, the pH of the system was adjusted to 8.2-8.6 using triethylamine and then filtered.

[0064] The pretreated zinc powder was prepared using the following steps: 370g of zinc powder was acid-washed and activated with 1.3% (w / w) dilute phosphoric acid, added to 700g of 55% (w / w) aqueous ethanol solution, 15g of γ-aminopropyltriethoxysilane was added, and the mixture was refluxed and stirred at 77℃ for 2.5h. 40g of fumed silica was added and stirring was continued for 15min. The mixture was then centrifuged, filtered, washed with deionized water, heat-treated at 110℃ for 80min, cooled, and pulverized to a D50 ≤ 5μm.

[0065] Component B includes: 58g of polyetheramine, 0.7g of 2,4,6-tris(dimethylaminomethyl)phenol, 4g of hyperbranched polyester dispersant, 7g of propylene glycol methyl ether, and 35g of water.

[0066] The preparation method of the above-mentioned water-based environmentally friendly two-component epoxy resin coating includes the following steps:

[0067] S1. Premix the core-shell epoxy resin emulsion and triethanolamine, add pretreated zinc powder and sonicate for 12 min at a frequency of 33 kHz and a power of 480 W. Add BYK-190 dispersant, corrosion inhibitor, fumed silica, propylene glycol methyl ether, and TEGO-8030 and disperse at high speed for 13 min at a speed of 1700 r / min. Pass the mixture through an 80-mesh filter to obtain component A.

[0068] S2. Stir polyetheramine, 2,4,6-tris(dimethylaminomethyl)phenol and hyperbranched polyester dispersant for 12 min at a stirring speed of 550 r / min, cool to room temperature, add propylene glycol methyl ether and water, and sonicate for 22 min at a sonic frequency of 33 kHz and a sonic power of 470 W to obtain component B.

[0069] Example 5

[0070] A water-based, environmentally friendly two-component epoxy resin coating includes component A and component B, wherein the mass ratio of component A to component B is 10:3.

[0071] Component A comprises: 350g of core-shell epoxy resin emulsion, 15g of triethanolamine, 350g of pretreated zinc powder, 3g of BYK-190 dispersant, 15g of corrosion inhibitor, 15g of fumed silica, 15g of propylene glycol methyl ether, and 15g of TEGO-8030. The corrosion inhibitor is composed of zinc phosphate, sodium molybdate, and cerium nitrate in a mass ratio of 3:0.7:0.5.

[0072] The core-shell epoxy resin emulsion was prepared using the following steps: Under nitrogen protection, 250g of polyester polyol, 100g of isophorone diisocyanate, and 35g of dimethylolpropionic acid were added to a reaction vessel and stirred at 75℃ for 2 hours at a stirring speed of 450r / min. The temperature was then lowered to 55℃, and 20g of triethylamine and 800g of deionized water were added. The mixture was stirred at 1500r / min for 15 minutes to obtain the prepolymer. 150g of glycidyl acrylate and 100g of methacrylic acid were then added... Methyl ester, 15g sodium dodecyl sulfate, and 400g deionized water were mixed and stirred at 45℃ for 15min at a stirring speed of 1500r / min to obtain a composite emulsion. 25wt% of the composite emulsion and 1.5g of ammonium persulfate were added to the prepolymer and stirred at 78℃ for 90min. The remaining composite emulsion and 6g of ammonium persulfate were added dropwise while stirring, and the mixture was stirred at 88℃ for 3h. After cooling to room temperature, the pH of the system was adjusted to 8.2-8.6 using triethylamine and then filtered.

[0073] The pretreated zinc powder was prepared using the following steps: 350g of zinc powder was acid-washed and activated with 1.5% dilute phosphoric acid, added to 800g of 50% ethanol aqueous solution, 20g of γ-aminopropyltriethoxysilane was added, and the mixture was refluxed and stirred at 75℃ for 3h. 30g of fumed silica was added and stirring was continued for 20min. The mixture was then centrifuged, filtered, washed with deionized water, heat-treated at 109℃ for 90min, cooled, and pulverized to D50≤5μm.

[0074] Component B includes: 55g of polyetheramine, 0.8g of 2,4,6-tris(dimethylaminomethyl)phenol, 3g of hyperbranched polyester dispersant, 8g of propylene glycol methyl ether, and 30g of water.

[0075] The preparation method of the above-mentioned water-based environmentally friendly two-component epoxy resin coating includes the following steps:

[0076] S1. Premix the core-shell epoxy resin emulsion and triethanolamine, add pretreated zinc powder and sonicate for 15 min at a frequency of 33 kHz and a power of 450 W. Add BYK-190 dispersant, corrosion inhibitor, fumed silica, propylene glycol methyl ether, and TEGO-8030 and disperse at a speed of 1500 r / min for 15 min. Pass the mixture through an 80-mesh filter to obtain component A.

[0077] S2. Stir polyetheramine, 2,4,6-tris(dimethylaminomethyl)phenol and hyperbranched polyester dispersant for 15 min at a stirring speed of 500 r / min, cool to room temperature, add propylene glycol methyl ether and water, and sonicate for 25 min at an ultrasonic frequency of 33 kHz and an ultrasonic power of 450 W to obtain component B.

[0078] Comparative Example 1

[0079] A water-based, environmentally friendly two-component epoxy resin coating includes component A and component B, wherein the mass ratio of component A to component B is 10:3.

[0080] Component A comprises: 350g of core-shell epoxy resin emulsion, 15g of triethanolamine, 350g of pretreated zinc powder, 3g of BYK-190 dispersant, 15g of corrosion inhibitor, 15g of fumed silica, 15g of propylene glycol methyl ether, and 15g of TEGO-8030. The corrosion inhibitor is composed of zinc phosphate, sodium molybdate, and cerium nitrate in a mass ratio of 3:0.7:0.5.

[0081] The core-shell epoxy resin emulsion was prepared using the following steps: Under nitrogen protection, 250g of polyester polyol, 100g of isophorone diisocyanate, and 35g of dimethylolpropionic acid were added to a reactor and stirred at 75℃ for 2 hours at a stirring speed of 450r / min. The mixture was then cooled to 55℃, and 20g of triethylamine and 800g of deionized water were added. The mixture was stirred at 1500r / min for 15 minutes to obtain a prepolymer. 150g of glycidyl acrylate, 100g of methyl methacrylate, 15g of sodium dodecyl sulfate, and 400g of deionized water were mixed and stirred at 45℃ for 15 minutes at a stirring speed of 1500r / min to obtain a composite emulsion. The composite emulsion and 7.5g of ammonium persulfate were added to the prepolymer and stirred at 78℃ for 90 minutes. The mixture was then stirred at 88℃ for 3 hours and cooled to room temperature. The pH of the system was adjusted to 8.2-8.6 using triethylamine, and the mixture was filtered.

[0082] The pretreated zinc powder was prepared using the following steps: 350g of zinc powder was acid-washed and activated with 1.5% dilute phosphoric acid, added to 800g of 50% ethanol aqueous solution, 20g of γ-aminopropyltriethoxysilane was added, and the mixture was refluxed and stirred at 75℃ for 3h. 30g of fumed silica was added and stirring was continued for 20min. The mixture was then centrifuged, filtered, washed with deionized water, heat-treated at 109℃ for 90min, cooled, and pulverized to D50≤5μm.

[0083] Component B includes: 55g of polyetheramine, 0.8g of 2,4,6-tris(dimethylaminomethyl)phenol, 3g of hyperbranched polyester dispersant, 8g of propylene glycol methyl ether, and 30g of water.

[0084] The preparation method of the above-mentioned water-based environmentally friendly two-component epoxy resin coating includes the following steps:

[0085] S1. Premix the core-shell epoxy resin emulsion and triethanolamine, add pretreated zinc powder and sonicate for 15 min at a frequency of 33 kHz and a power of 450 W. Add BYK-190 dispersant, corrosion inhibitor, fumed silica, propylene glycol methyl ether, and TEGO-8030 and disperse at a speed of 1500 r / min for 15 min. Pass the mixture through an 80-mesh filter to obtain component A.

[0086] S2. Stir polyetheramine, 2,4,6-tris(dimethylaminomethyl)phenol and hyperbranched polyester dispersant for 15 min at a stirring speed of 500 r / min, cool to room temperature, add propylene glycol methyl ether and water, and sonicate for 25 min at an ultrasonic frequency of 33 kHz and an ultrasonic power of 450 W to obtain component B.

[0087] Comparative Example 2

[0088] A water-based, environmentally friendly two-component epoxy resin coating includes component A and component B, wherein the mass ratio of component A to component B is 10:3.

[0089] Component A comprises: 350g of core-shell epoxy resin emulsion, 15g of triethanolamine, 350g of pretreated zinc powder, 3g of BYK-190 dispersant, 15g of corrosion inhibitor, 15g of fumed silica, 15g of propylene glycol methyl ether, and 15g of TEGO-8030. The corrosion inhibitor is composed of zinc phosphate, sodium molybdate, and cerium nitrate in a mass ratio of 3:0.7:0.5.

[0090] The core-shell epoxy resin emulsion was prepared using the following steps: Under nitrogen protection, 250g of polyester polyol, 100g of isophorone diisocyanate, and 35g of dimethylolpropionic acid were added to a reaction vessel and stirred at 75℃ for 2 hours at a stirring speed of 450r / min. The temperature was then lowered to 55℃, and 20g of triethylamine and 800g of deionized water were added. The mixture was stirred at 1500r / min for 15 minutes to obtain the prepolymer. 150g of glycidyl acrylate and 100g of methacrylic acid were then added... Methyl ester, 15g sodium dodecyl sulfate, and 400g deionized water were mixed and stirred at 45℃ for 15min at a stirring speed of 1500r / min to obtain a composite emulsion. 25wt% of the composite emulsion and 1.5g of ammonium persulfate were added to the prepolymer and stirred at 78℃ for 90min. The remaining composite emulsion and 6g of ammonium persulfate were added dropwise while stirring, and the mixture was stirred at 88℃ for 3h. After cooling to room temperature, the pH of the system was adjusted to 8.2-8.6 using triethylamine and then filtered.

[0091] The pretreated zinc powder was prepared using the following steps: 350g of zinc powder was acid-washed and activated with 1.5% dilute phosphoric acid, added to 800g of 50% ethanol aqueous solution, 30g of fumed silica was added and stirred for 20min, centrifuged, filtered, washed with deionized water, heat-treated at 109℃ for 90min, cooled, and pulverized to D50≤5μm.

[0092] Component B includes: 55g of polyetheramine, 0.8g of 2,4,6-tris(dimethylaminomethyl)phenol, 3g of hyperbranched polyester dispersant, 8g of propylene glycol methyl ether, and 30g of water.

[0093] The preparation method of the above-mentioned water-based environmentally friendly two-component epoxy resin coating includes the following steps:

[0094] S1. Premix the core-shell epoxy resin emulsion and triethanolamine, add pretreated zinc powder and sonicate for 15 min at a frequency of 33 kHz and a power of 450 W. Add BYK-190 dispersant, corrosion inhibitor, fumed silica, propylene glycol methyl ether, and TEGO-8030 and disperse at a speed of 1500 r / min for 15 min. Pass the mixture through an 80-mesh filter to obtain component A.

[0095] S2. Stir polyetheramine, 2,4,6-tris(dimethylaminomethyl)phenol and hyperbranched polyester dispersant for 15 min at a stirring speed of 500 r / min, cool to room temperature, add propylene glycol methyl ether and water, and sonicate for 25 min at an ultrasonic frequency of 33 kHz and an ultrasonic power of 450 W to obtain component B.

[0096] The A component of the two-component epoxy resin coatings obtained in Example 5 and Comparative Examples 1-2 was stored at room temperature for 12 months. It was found that the A component of Example 5 did not undergo stratification or precipitation after 12 months of storage at room temperature; while the A component of Comparative Example 1 showed stratification after 12 months of storage at room temperature, and the A component of Comparative Example 2 showed stratification and precipitation after only 6 months.

[0097] The two-component epoxy resin coatings obtained in Example 5 and Comparative Examples 1-2 were sprayed as follows: A Q195 steel plate (after cleaning and grinding) was used as the substrate. The components A and B of each coating were mixed evenly and allowed to stand for 30 minutes. The coating was then sprayed onto the substrate surface three times using a high-pressure airless spraying method. The spray gun pressure was 15 MPa and the spray gun moving speed was 1 m / s. The film thickness of each spray was 45 ± 5 μm, and the total coating thickness was 135 ± 10 μm.

[0098] The impact resistance of the above-mentioned coatings was determined according to GB / T 1732-2020 "Test Method for Impact Resistance of Paint Films", with the maximum height without cracking used to characterize the impact resistance. The flexibility of the above-mentioned coatings was determined according to GB / T 1731-2020 "Test Method for Flexibility of Paint Films and Putty Films".

[0099] like Figure 1 As shown, the coating film made with the epoxy resin coating obtained in Example 5 has the best impact resistance and flexibility, which is slightly better than Comparative Example 2 and significantly better than Comparative Example 1.

[0100] The adhesion of the above-mentioned coatings was determined according to GB / T 5210-2006 "Paints and Varnishes - Pull-off Adhesion Test". For example... Figure 2 As shown, the coating film prepared using the epoxy resin coating obtained in Example 5 has the highest adhesion, which is better than that of Comparative Examples 1-2 (P<0.05).

[0101] The water resistance, acid resistance (10% hydrochloric acid), and alkali resistance (30% sodium hydroxide solution) of each group of coatings were tested according to GB / T 1733-1993 "Determination of Water Resistance of Coatings". The salt spray resistance of each group of coatings was tested according to GB / T 10125-2012 "Artificial Atmosphere Corrosion Test - Salt Spray Test". The damp heat resistance of each group of coatings was tested according to GB / T 1740-2007 "Determination of Damp Heat Resistance of Coatings". The results are shown in Table 1.

[0102] Table 1. Results of epoxy resin coatings obtained in Example 5 and Comparative Examples 1-2

[0103]

[0104] Table 1 shows that the coating film made using the epoxy resin coating obtained in Example 5 has excellent water resistance and long-term anti-corrosion ability.

[0105] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A water-based, environmentally friendly two-component epoxy resin coating, characterized in that, It includes component A and component B, wherein the mass ratio of component A to component B is 10:1-5; Component A, by mass, includes: 30-40 parts of core-shell epoxy resin emulsion, 1-2 parts of organic alcohol amine, 30-40 parts of pretreated zinc powder, 0.1-0.5 parts of polycarboxylate dispersant, 1-2 parts of corrosion inhibitor, 1-2 parts of thixotropic agent, 1-2 parts of cosolvent, and 1-2 parts of defoamer. The core-shell epoxy resin emulsion is prepared by the following steps: Under nitrogen protection, polyester polyol, isophorone diisocyanate, and dimethylolpropionic acid are mixed and stirred at 70-80℃ for 1-3 hours. The mixture is then cooled to 50-60℃, and triethylamine and water are added and stirred for 10-20 minutes to obtain a prepolymer. Glycidyl acrylate, methyl methacrylate, emulsifier, and water are mixed and stirred at 40-50℃ for 10-20 minutes to obtain a composite emulsion. A portion of the composite emulsion and initiator are added to the prepolymer and stirred at 75-82℃ for 1-2 hours. While stirring, the remaining composite emulsion and initiator are added dropwise, and the mixture is stirred at 85-90℃ for 2-4 hours. The mixture is then cooled to room temperature, the pH of the system is adjusted to 8.2-8.6, and the mixture is filtered. Both the composite emulsion and the initiator are added sequentially. The mass ratio of the composite emulsion added first to the composite emulsion added later is 20-30:70-80, and the mass ratio of the initiator added first to the initiator added later is 0.1-0.2:0.3-1. The pretreated zinc powder is prepared by the following steps: zinc powder is acid-washed and activated with dilute phosphoric acid, added to an ethanol aqueous solution, γ-aminopropyltriethoxysilane is added, refluxed and stirred at 70-80℃ for 2-4h, fumed silica is added and stirring is continued for 10-30min, centrifuged, filtered, washed, heat-treated at 105-112℃ for 1-2h, cooled, and pulverized to D50≤5μm; Component B, by weight, includes: 50-60 parts of polyetheramine, 0.5-1 part of curing accelerator, 1-5 parts of hyperbranched polyester dispersant, 5-10 parts of co-solvent, and 20-40 parts of water.

2. The water-based environmentally friendly two-component epoxy resin coating according to claim 1, characterized in that, The corrosion inhibitors include zinc phosphate, sodium molybdate, and cerium nitrate, with a mass ratio of 1-5:0.5-1:0.1-1.

3. The water-based environmentally friendly two-component epoxy resin coating according to claim 1, characterized in that, The organic alcohol amine is triethanolamine; the polycarboxylate dispersant is BYK-190 dispersant; the thixotropic agent is fumed silica; the cosolvent is propylene glycol methyl ether; and the curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

4. The water-based environmentally friendly two-component epoxy resin coating according to claim 1, characterized in that, The mass ratio of polyester polyol, isophorone diisocyanate, dimethylolpropionic acid, triethylamine, glycidyl acrylate, methyl methacrylate, emulsifier, and initiator is 20-30:8-12:2-4:1-3:10-20:5-15:1-2:0.4-1.

2.

5. The water-based environmentally friendly two-component epoxy resin coating according to claim 1, characterized in that, The mass ratio of zinc powder, γ-aminopropyltriethoxysilane, and fumed silica is 30-40:1-3:1-5.

6. A method for preparing a water-based environmentally friendly two-component epoxy resin coating as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Premix the core-shell epoxy resin emulsion and organic alcohol amine, add pretreated zinc powder and ultrasonically treat for 10-20 min, add polycarboxylate dispersant, corrosion inhibitor, thixotropic agent, cosolvent and defoamer and disperse at high speed for 10-20 min, filter to obtain component A; S2. Stir the polyetheramine, curing accelerator, and hyperbranched polyester dispersant for 10-20 minutes, cool to room temperature, add co-solvent and water, and sonicate for 20-30 minutes to obtain component B.

7. A method of using the water-based environmentally friendly two-component epoxy resin coating as described in any one of claims 1-5, characterized in that, The process includes the following steps: mix component A and component B evenly, let stand for 20-40 minutes, and then spray under high pressure to a total thickness of 120-150 μm.

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