Concrete conglomerate anticorrosive coating and preparation method thereof

Abstract

The invention relates to the technical field of anticorrosive coatings, in particular to a concrete conglomerate anticorrosive coating and a preparation method thereof.The concrete conglomerate anticorrosive coating comprises a bottom coating, a transition bonding layer and a surface coating, and the bottom coating is prepared from, by weight, 50-70 parts of epoxy resin, 20-30 parts of a curing agent, 5-10 parts of a nano-composite, 2-5 parts of a silane coupling agent, 1-3 parts of a dispersing agent and 30-50 parts of a solvent; the transition bonding layer is prepared from the following raw materials in parts by weight: 40-50 parts of waterborne polyurethane resin, 10-15 parts of nano zinc oxide and 5-10 parts of a polydopamine solution with the concentration of 2-3g / L; the surface coating is prepared from the following raw materials in parts by weight: 60-80 parts of acrylic resin, 20-30 parts of pigment filler, 1-3 parts of a flatting agent, 1-3 parts of a defoaming agent, 2-5 parts of a preservative and 40-60 parts of a solvent. The contradiction between flexibility and hardness of a traditional coating is solved, the drying efficiency is greatly improved, the defects that in the prior art, a coating is prone to cracking and insufficient in binding force are overcome, and remarkable technical progress and industrial application value are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-corrosion coatings, and in particular to a concrete conglomerate anti-corrosion coating and a preparation method thereof. Background Art

[0002] Concrete conglomerate is a commonly used material in construction, widely used in infrastructure such as bridges, tunnels, ports, and water conservancy facilities. However, due to long-term exposure to the external environment, concrete conglomerate is susceptible to various corrosive factors, such as erosion by acid, alkali, and salt solutions, chloride ion penetration, freeze-thaw cycles, and ultraviolet radiation. These factors can cause structural damage and reduce strength of the concrete conglomerate, thereby affecting the safety and durability of the entire building structure.

[0003] Currently, to improve the corrosion resistance of concrete gravel, an anti-corrosion coating is usually applied to its surface. There are many types of anti-corrosion coatings available, such as epoxy resin coatings, polyurethane coatings, and acrylic coatings. However, these coatings have some shortcomings in practical applications. For example, while epoxy resin coatings have good adhesion and chemical resistance, they have poor flexibility and are prone to cracking; polyurethane coatings have good weather resistance but poor solvent resistance; and acrylic coatings are easy to apply but have limited corrosion resistance. Furthermore, existing anti-corrosion coating preparation methods are relatively complex and costly, and the coatings lack ideal adhesion to the concrete gravel surface, making them prone to flaking and falling off, which affects the corrosion resistance.

[0004] Therefore, there is an urgent need for a method for preparing an anti-corrosion coating with simple preparation process, low cost, excellent anti-corrosion performance and strong bonding with the concrete gravel surface. Summary of the Invention

[0005] In order to solve the problems mentioned in the above background technology, the present invention provides a concrete conglomerate anti-corrosion coating and a preparation method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A concrete conglomerate anti-corrosion coating comprises a primer, a transition bonding layer, and a topcoat, wherein the primer is made of the following raw materials in parts by weight: 50-70 parts of epoxy resin, 20-30 parts of curing agent, 5-10 parts of nanocomposite, 2-5 parts of silane coupling agent, 1-3 parts of dispersant, 30-50 parts of solvent; The transition bonding layer is made of the following raw materials in parts by weight: 40-50 parts of waterborne polyurethane resin, 10-15 parts of nano zinc oxide, and 5-10 parts of modified polydopamine solution with a concentration of 2-3g / L; The preparation method of the modified polydopamine solution comprises the following steps: 3-Aminophenylboronic acid and glycidyl methacrylate are added to anhydrous ethanol, and hydroquinone is added. Under nitrogen protection, the mixture is stirred at 60-65° C. for 4-6 hours to obtain a functional monomer 3-APBA-GMA.

[0007] Weigh dopamine hydrochloride, 3-APBA-GMA and tannic acid, add them to Tris-HCl buffer solution (pH = 8.5, 10 mmol / L), stir until completely dissolved, then add β-cyclodextrin, stir evenly, and stir the solution at room temperature for 20-24 hours to obtain a modified polydopamine solution.

[0008] By presynthesizing the functional monomer 3-APBA-GMA containing borate and epoxy groups, dynamic borate covalent bonds and epoxy-reactive groups were introduced into the polydopamine molecular structure. The borate bond is pH-responsive and dynamically reversible, stable in alkaline environments but capable of reversible breakage and recombination in acidic conditions, endowing the material with self-healing capabilities. The epoxy groups undergo a ring-opening reaction with the hydroxyl groups on the surface of the concrete conglomerate, strengthening the chemical bonding between the coating and the substrate and significantly improving adhesion.

[0009] The transitional bonding layer forms hydrogen and covalent bonds with the concrete surface through the catechol groups of dopamine, while also forming an interpenetrating network structure with the epoxy resin primer. The catechol groups of polydopamine form coordination bonds with the iron and calcium ions on the concrete surface, while reacting with the isocyanate groups of the waterborne polyurethane to form urea bonds. This creates a 5-10μm transition layer between the primer and the substrate, significantly reducing the modulus gradient of the coating system and significantly reducing interfacial stress concentration.

[0010] The topcoat is made of the following raw materials in parts by weight: 60-80 parts of acrylic resin, 20-30 parts of pigments and fillers, 1-3 parts of leveling agent, 1-3 parts of defoaming agent, 2-5 parts of preservative, and 40-60 parts of solvent.

[0011] Preferably, the method for preparing the nanocomposite comprises the following steps: S1. Take a 1.5 mg / mL graphene oxide dispersion, add 25% ammonia water, adjust the pH to 8.5-9.0, control stirring at 800-1000 r / min for 30-45 min, and add ethyl orthosilicate dropwise at a drop rate of 1 drop / second to ensure that ethyl orthosilicate evenly contacts the GO surface. Maintain the reaction temperature at 60-65°C and the reaction time for 3-4 h to obtain a silica-coated GO dispersion. During this period, use ammonia water to maintain the pH = 8.5-9.5 (test once every 30 minutes).

[0012] Under alkaline conditions, ethyl orthosilicate is first hydrolyzed to generate Si(OH)4, which then condenses to form a -Si-O-Si- network, which is adsorbed on the hydroxyl sites on the GO surface through hydrogen bonding and gradually deposited to form a silica shell with a thickness of 5-10nm.

[0013] S2. Add isopropyl tri(dioctyl pyrophosphate) titanate to a mixed solution of ethanol / water in a volume ratio of 3:1, add glacial acetic acid to adjust the pH to 4.5, and stir at room temperature for 30-40 minutes to hydrolyze the isopropyl tri(dioctyl pyrophosphate) titanate to generate an intermediate containing active titanium hydroxyl group (-TiOH).

[0014] S3. Add the silica-coated GO dispersion obtained in S1 to the intermediate in S2, raise the temperature to 50-55°C, and stir the reaction for 6-8 hours.

[0015] Isopropyl tri(dioctylpyrophosphate) titanate contains a readily hydrolyzed alkoxy group in its molecular structure. In an ethanol / water mixture, hydrolysis occurs under acidic conditions, generating an intermediate containing a reactive titanium hydroxyl group (-TiOH). The ethanol / water solvent ensures the solubility of the coupling agent while providing the aqueous environment necessary for hydrolysis.

[0016] S4. After the reaction is completed, the precipitate is collected by centrifugation and washed with anhydrous ethanol 2-4 times to remove the unreacted coupling agent. The product is dried in a vacuum drying oven at 60-70°C for 10-12 hours and ground to obtain a powdered core-shell structure complex with a particle size of ≤100 nm.

[0017] Preferably, the curing agent is a phenalkamine epoxy curing agent.

[0018] Preferably, the silane coupling agent is one or more of 3-(2,3-epoxypropoxy)propyltriethoxysilane (KH-561), 3-mercaptopropyltriethoxysilane (KH-580), and 3-aminopropyltriethoxysilane (KH-550).

[0019] Preferably, the dispersant is one or more of polyacrylate sodium salt solution, polycarboxylate sodium salt solution, Dow 731A, BYK-155, BYK-190, and BYK-192.

[0020] Preferably, the solvent in the primer layer is toluene and / or xylene.

[0021] Preferably, the solvent in the topcoat layer is ethyl acetate.

[0022] Preferably, the pigments and fillers are one or more of titanium dioxide, barium sulfate, and talc.

[0023] Preferably, the leveling agent is one or more of BYK-331, BYK-333, BYK-378, and BASF EFKA FL3772.

[0024] Preferably, the defoaming agent is a polydimethylsiloxane-based defoaming agent.

[0025] Preferably, the preservative is 2-methyl-4-isothiazolin-3-one and / or 1,2-benzisothiazolin-3-one.

[0026] A method for preparing a concrete conglomerate anti-corrosion coating further comprises the following steps: S1. Weigh the raw materials according to the weight parts, first add the epoxy resin and solvent into the reactor, stir evenly, then add the nanocomposite and dispersant, stir at a speed of 500-800 r / min for 30-60 min, then add the silane coupling agent and curing agent, and continue stirring for 10-20 min to obtain a primer; Apply the primer evenly by brushing or spraying it on the surface of the concrete gravel, with the coating thickness controlled at 50-100 μm, and then dry it at room temperature for 2-4 hours; S2, spraying the waterborne polyurethane resin, nano zinc oxide, and modified polydopamine solution onto the base coat to a thickness of 20-30 μm, and drying at 60° C. for 30 min to form a dense intermediate layer; S3, adding acrylic resin and solvent into the reaction kettle, stirring evenly, then adding pigments, fillers, leveling agents, defoaming agents and preservatives, stirring at a speed of 800-1000r / min for 60-90min until the materials are evenly mixed to obtain a topcoat liquid; The surface coating liquid is evenly brushed or sprayed on the surface of the concrete gravel after the dense middle layer is dried, the coating thickness is controlled at 100-150μm, and then dried at room temperature for 24-48h to obtain the concrete gravel anti-corrosion coating.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention doubles the salt spray resistance time of the coating and increases the resistance by two orders of magnitude through the synergistic effect of composite nanofillers and interfacial chemical bonding. At the same time, it solves the contradiction between the flexibility and hardness of traditional coatings, greatly improves the drying efficiency, and overcomes the defects of easy cracking and insufficient bonding strength of the coating in the existing technology. It has significant technological progress and industrial application value.

[0028] 2. The present invention provides a transitional bonding layer, where the catechol groups of dopamine form hydrogen and covalent bonds with the concrete surface, while also forming an interpenetrating network structure with the epoxy resin primer. The catechol groups of polydopamine form coordination bonds with the iron and calcium ions on the concrete surface, while reacting with the isocyanate groups of the waterborne polyurethane to form urea bonds. This creates a 5-10 μm transition layer between the primer and the substrate, significantly reducing the modulus gradient of the coating system and significantly reducing interfacial stress concentration. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0031] Epoxy resin was purchased from Shandong Jinhong New Material Technology Co., Ltd., item number 11212; The waterborne polyurethane resin was purchased from Hunan Jitianxin Technology Co., Ltd., model RY8402; Nano zinc oxide was purchased from Nanjing Baoket New Materials Co., Ltd., with a CAS number of 1314-13-2; Graphene oxide dispersion was purchased from Kerui Nano (Guangdong) Co., Ltd. with a CAS number of 7782-42-5.

[0032] Preparation Example 1: The preparation method of the nanocomposite comprises the following steps: S1. Take 50 mL of 1.5 mg / mL graphene oxide dispersion, add 1 mL of 25% ammonia water, adjust the pH to 8.5, control stirring at 800 r / min for 30 min, and add 2 mL of tetraethyl orthosilicate (pre-dissolved in 5 mL of anhydrous ethanol) dropwise at a drop rate of 1 drop / second to ensure that tetraethyl orthosilicate evenly contacts the GO surface. Maintain the reaction temperature at 60°C and the reaction time for 3 h to obtain a silica-coated GO dispersion. During this period, use ammonia water to maintain the pH = 8.5 (test once every 30 minutes).

[0033] S2. Add 2 mL of isopropyl tris(dioctyl pyrophosphate) titanate to 20 mL of a 3:1 ethanol / water mixed solution, add 0.1 mL of glacial acetic acid to adjust the pH to 4.5, and stir at room temperature for 30 minutes to hydrolyze the isopropyl tris(dioctyl pyrophosphate) titanate to generate an intermediate containing active titanium hydroxyl group (-TiOH).

[0034] S3. Add the silica-coated GO dispersion obtained in S1 to the intermediate in S2, raise the temperature to 50°C, and stir the reaction for 6 hours.

[0035] S4. After the reaction is completed, the precipitate is collected by centrifugation and washed twice with anhydrous ethanol to remove the unreacted coupling agent. The product is dried in a vacuum drying oven at 60°C for 10 h and ground to obtain a powdered core-shell structure complex with a particle size of ≤100 nm.

[0036] Preparation Example 2: The preparation method of the nanocomposite comprises the following steps: S1. Take 50 mL of 1.5 mg / mL graphene oxide dispersion, add 1 mL of 25% ammonia water, adjust the pH to 9.0, control stirring at 900 r / min for 40 min, and add 2 mL of tetraethyl orthosilicate (pre-dissolved in 5 mL of anhydrous ethanol) dropwise at a drop rate of 1 drop / second to ensure that tetraethyl orthosilicate evenly contacts the GO surface. Maintain the reaction temperature at 62°C and the reaction time for 3 h to obtain a silica-coated GO dispersion. During this period, use ammonia water to maintain the pH = 9.0 (test once every 30 minutes).

[0037] S2. Add 2 mL of isopropyl tris(dioctyl pyrophosphate) titanate to 20 mL of a 3:1 ethanol / water mixed solution, add 0.1 mL of glacial acetic acid to adjust the pH to 4.5, and stir at room temperature for 35 minutes to hydrolyze the isopropyl tris(dioctyl pyrophosphate) titanate to generate an intermediate containing active titanium hydroxyl group (-TiOH).

[0038] S3. Add the silica-coated GO dispersion obtained in S1 to the intermediate in S2, raise the temperature to 55°C, and stir the reaction for 7 hours.

[0039] S4. After the reaction is completed, the precipitate is collected by centrifugation and washed three times with anhydrous ethanol to remove the unreacted coupling agent. The product is dried in a vacuum drying oven at 65°C for 11 hours and ground to obtain a powdered core-shell structure complex with a particle size of ≤100 nm.

[0040] Preparation Example 3: The preparation method of the nanocomposite comprises the following steps: S1. Take 50 mL of 1.5 mg / mL graphene oxide dispersion, add 1 mL of 25% ammonia water, adjust the pH to 9.0, control stirring at 1000 r / min for 45 minutes, and add 2 mL of tetraethyl orthosilicate (pre-dissolved in 5 mL of anhydrous ethanol) dropwise at a drop rate of 1 drop / second to ensure that tetraethyl orthosilicate evenly contacts the GO surface. Maintain the reaction temperature at 65°C and the reaction time for 4 hours to obtain a silica-coated GO dispersion. During this period, use ammonia water to maintain the pH = 9.5 (test once every 30 minutes).

[0041] S2. Add 2 mL of isopropyl tris(dioctyl pyrophosphate) titanate to 20 mL of a 3:1 ethanol / water mixed solution, add 0.1 mL of glacial acetic acid to adjust the pH to 4.5, and stir at room temperature for 40 minutes to hydrolyze the isopropyl tris(dioctyl pyrophosphate) titanate to generate an intermediate containing active titanium hydroxyl group (-TiOH).

[0042] S3. Add the silica-coated GO dispersion obtained in S1 to the intermediate in S2, raise the temperature to 55°C, and stir the reaction for 8 hours.

[0043] S4. After the reaction is completed, the precipitate is collected by centrifugation and washed with anhydrous ethanol four times to remove the unreacted coupling agent. The product is dried in a vacuum drying oven at 70°C for 12 hours and ground to obtain a powdered core-shell structure complex with a particle size of ≤100 nm.

[0044] Preparation Example 4: The preparation method of the modified polydopamine solution comprises the following steps: 12.5 g of 3-aminophenylboronic acid and 17 g of glycidyl methacrylate were added to 500 mL of anhydrous ethanol, and 0.65 g of hydroquinone was added. Under nitrogen protection, the mixture was stirred at 65° C. for 6 h to obtain the functional monomer 3-APBA-GMA.

[0045] Weigh 2 g of dopamine hydrochloride, 0.5 g of 3-APBA-GMA, and 0.3 g of tannic acid, add them to 100 mL of Tris-HCl buffer solution (pH = 8.5, 10 mmol / L), stir until completely dissolved, then add 0.1 g of β-cyclodextrin, stir evenly, and stir the solution at room temperature for 24 h to obtain a modified polydopamine solution.

[0046] Example 1: A method for preparing a concrete conglomerate anti-corrosion coating, further comprising the following steps: S1, first add 50 parts of epoxy resin and 40 parts of toluene into a reactor and stir evenly, then add 5 parts of the nanocomposite prepared in Preparation Example 1 and 2 parts of polyacrylate sodium salt solution, stir at a speed of 500r / min for 60min, then add 2 parts of silane coupling agent KH-561 and 20 parts of phenalkamine epoxy curing agent, continue stirring for 10min to obtain a primer; Apply the primer evenly by brushing or spraying it on the surface of the concrete gravel, with the coating thickness controlled at 50 μm, and then dry it at room temperature for 2 hours; S2. 40 parts of the aqueous polyurethane resin, 15 parts of nano-zinc oxide, and 5 parts of the modified polydopamine solution with a concentration of 2 g / L prepared in Preparation Example 4 were mixed and sprayed onto the base coat layer to a thickness of 20 μm. The mixture was dried at 60° C. for 30 min to form a dense intermediate layer. S3, add 60 parts of acrylic resin and 40 parts of ethyl acetate into the reactor, stir evenly, then add 20 parts of titanium dioxide, 1 part of BYK-331, 1 part of polydimethylsiloxane defoamer and 3 parts of 2-methyl-4-isothiazoline-3-one, stir at a speed of 800 r / min for 60 minutes until the materials are evenly mixed to obtain a topcoat liquid, The surface coating liquid is evenly brushed or sprayed on the surface of the concrete gravel after the dense middle layer is dried, the coating thickness is controlled at 100 μm, and then dried at room temperature for 24 hours to obtain the concrete gravel anti-corrosion coating.

[0047] Example 2: A method for preparing a concrete conglomerate anti-corrosion coating, further comprising the following steps: S1. First, 60 parts of epoxy resin and 35 parts of xylene were added to a reactor and stirred evenly. Then, 6 parts of the nanocomposite prepared in Preparation Example 2 and 2 parts of BYK-155 were added. The mixture was stirred at a speed of 600 r / min for 50 min. Then, 2 parts of silane coupling agent KH-580 and 25 parts of phenalkamine epoxy curing agent were added. The mixture was stirred for 15 min to obtain a primer. Apply the primer evenly by brushing or spraying it on the surface of the concrete gravel, with the coating thickness controlled at 70 μm, and then dry it at room temperature for 3 hours; S2. 45 parts of the aqueous polyurethane resin, 12 parts of nano zinc oxide, and 7 parts of the modified polydopamine solution with a concentration of 2.5 g / L prepared in Preparation Example 4 were mixed and sprayed onto the base coat layer to a thickness of 25 μm. The mixture was dried at 60° C. for 30 min to form a dense intermediate layer. S3. Add 60 parts of acrylic resin and 60 parts of ethyl acetate into the reactor and stir evenly. Then add 30 parts of barium sulfate, 1 part of BYK-333, 1 part of polydimethylsiloxane defoamer and 2 parts of 1,2-benzisothiazolin-3-one, and stir at a speed of 900 r / min for 80 minutes until the materials are evenly mixed to obtain a topcoat liquid. The surface coating liquid is evenly brushed or sprayed on the surface of the concrete gravel after the dense middle layer is dried, the coating thickness is controlled at 120μm, and then dried at room temperature for 30 hours to obtain the concrete gravel anti-corrosion coating.

[0048] Example 3: A method for preparing a concrete conglomerate anti-corrosion coating, further comprising the following steps: S1. First, 70 parts of epoxy resin and 50 parts of xylene were added to a reactor and stirred evenly. Then, 10 parts of the nanocomposite prepared in Preparation Example 3 and 2 parts of BYK-192 were added, and stirred at a speed of 800 r / min for 60 min. Then, 5 parts of silane coupling agent KH-550 and 20 parts of phenalkamine epoxy curing agent were added, and stirring was continued for 20 min to obtain a primer solution. Apply the primer evenly by brushing or spraying it on the surface of the concrete gravel, with the coating thickness controlled at 100 μm, and then dry it at room temperature for 4 hours; S2. 50 parts of the aqueous polyurethane resin, 15 parts of nano zinc oxide, and 5 parts of the modified polydopamine solution with a concentration of 3 g / L prepared in Preparation Example 4 were mixed and sprayed onto the base coat layer to a thickness of 30 μm. The mixture was dried at 60° C. for 30 min to form a dense intermediate layer. S3, 80 parts of acrylic resin and 40 parts of ethyl acetate were added to the reactor and stirred evenly, and then 30 parts of talc, 3 parts of BASF EFKA FL 3772, 3 parts of polydimethylsiloxane-based defoaming agent and 5 parts of 2-methyl-4-isothiazoline-3-one were added, and stirred at a speed of 1000 r / min for 90 minutes until the materials were evenly mixed to obtain a topcoat liquid. The surface coating liquid is evenly brushed or sprayed on the surface of the concrete gravel after the dense middle layer is dried, the coating thickness is controlled at 150 μm, and then dried at room temperature for 48 hours to obtain the concrete gravel anti-corrosion coating.

[0049] Example 4: A method for preparing a concrete conglomerate anti-corrosion coating, further comprising the following steps: S1, first add 50 parts of epoxy resin and 40 parts of xylene into a reactor and stir evenly, then add 5 parts of the nanocomposite prepared in Preparation Example 2 and 2 parts of polyacrylate sodium salt solution, stir at a speed of 500r / min for 60min, then add 2 parts of silane coupling agent KH-580 and 20 parts of phenalkamine epoxy curing agent, continue stirring for 10min to obtain a primer; Apply the primer evenly by brushing or spraying it on the surface of the concrete gravel, with the coating thickness controlled at 50 μm, and then dry it at room temperature for 2 hours; S2. 40 parts of the aqueous polyurethane resin, 15 parts of nano-zinc oxide, and 5 parts of the modified polydopamine solution with a concentration of 2 g / L prepared in Preparation Example 4 were mixed and sprayed onto the base coat layer to a thickness of 20 μm. The mixture was dried at 60° C. for 30 min to form a dense intermediate layer. S3, add 60 parts of acrylic resin and 40 parts of ethyl acetate into the reaction kettle, stir evenly, then add 20 parts of titanium dioxide, 1 part of BYK-378, 1 part of polydimethylsiloxane defoamer and 3 parts of 2-methyl-4-isothiazoline-3-one, stir at a speed of 800 r / min for 60 minutes until the materials are evenly mixed to obtain a topcoat liquid, The surface coating liquid is evenly brushed or sprayed on the surface of the concrete gravel after the dense middle layer is dried, the coating thickness is controlled at 110 μm, and then dried at room temperature for 35 hours to obtain the concrete gravel anti-corrosion coating.

[0050] Example 5: A method for preparing a concrete conglomerate anti-corrosion coating further comprising the following steps: S1. First, 60 parts of epoxy resin and 35 parts of xylene were added to a reactor and stirred evenly. Then, 6 parts of the nanocomposite prepared in Preparation Example 1 and 2 parts of BYK-192 were added. The mixture was stirred at a speed of 700 r / min for 60 min. Then, 2 parts of silane coupling agent KH-580 and 25 parts of phenalkamine epoxy curing agent were added. The mixture was stirred for 20 min to obtain a primer. Apply the primer evenly by brushing or spraying it on the surface of the concrete gravel, with the coating thickness controlled at 90 μm, and then dry it at room temperature for 3 hours; S2. 45 parts of the aqueous polyurethane resin, 12 parts of nano zinc oxide, and 7 parts of the modified polydopamine solution with a concentration of 3 g / L prepared in Preparation Example 4 were mixed and sprayed onto the base coat layer to a coating thickness of 25 μm. The mixture was dried at 60° C. for 30 min to form a dense intermediate layer. S3. Add 60 parts of acrylic resin and 60 parts of ethyl acetate into a reaction kettle and stir evenly. Then add 30 parts of barium sulfate, 1 part of BYK-333, 1 part of polydimethylsiloxane-based defoamer and 2 parts of 2-methyl-4-isothiazoline-3-one, and stir at a speed of 900 r / min for 80 minutes until the materials are evenly mixed to obtain a topcoat liquid; The surface coating liquid is evenly brushed or sprayed on the surface of the concrete gravel after the dense middle layer is dried, the coating thickness is controlled at 100 μm, and then dried at room temperature for 30 hours to obtain the concrete gravel anti-corrosion coating.

[0051] Example 6: A method for preparing a concrete conglomerate anti-corrosion coating further comprising the following steps: S1. First, 70 parts of epoxy resin and 50 parts of xylene were added to a reactor and stirred evenly. Then, 10 parts of the nanocomposite prepared in Preparation Example 2 and 2 parts of Dow 731A were added, and stirred at a speed of 750 r / min for 55 min. Then, 5 parts of silane coupling agent KH-550 and 20 parts of phenalkamine epoxy curing agent were added, and stirring was continued for 15 min to obtain a primer solution. Apply the primer evenly by brushing or spraying it on the surface of the concrete gravel, with the coating thickness controlled at 90 μm, and then dry it at room temperature for 4 hours; S2. 50 parts of the aqueous polyurethane resin, 15 parts of nano zinc oxide, and 5 parts of the modified polydopamine solution with a concentration of 3 g / L prepared in Preparation Example 4 were mixed and sprayed onto the base coat layer to a thickness of 30 μm. The mixture was dried at 60° C. for 30 min to form a dense intermediate layer. S3, 80 parts of acrylic resin and 40 parts of ethyl acetate were added to the reactor and stirred evenly, and then 30 parts of talc, 3 parts of BASF EFKA FL 3772, 3 parts of polydimethylsiloxane-based defoaming agent and 5 parts of 2-methyl-4-isothiazoline-3-one were added, and stirred at a speed of 900 r / min for 70 minutes until the materials were evenly mixed to obtain a topcoat liquid. The surface coating liquid is evenly brushed or sprayed on the surface of the concrete gravel after the dense middle layer is dried, the coating thickness is controlled at 120μm, and then dried at room temperature for 40 hours to obtain the concrete gravel anti-corrosion coating.

[0052] Comparative Example 1: The difference between this comparative example and Example 1 is that the nanocomposite prepared in Preparation Example 1 is replaced by nano-silicon dioxide, which is purchased from Hubei Huifu E-Commerce Co., Ltd.

[0053] Comparative Example 2: This comparative example differs from Example 1 in that the nanocomposite prepared in Preparation Example 1 is replaced with graphene oxide, which is purchased from Sichuan Kenye Technology Development Co., Ltd. and has a model number of KY CRG1210.

[0054] Comparative Example 3: The difference between this comparative example and Example 1 is that in the preparation process of the nanocomposite in Preparation Example 1, ethyl orthosilicate is not added.

[0055] Comparative Example 4: This comparative example differs from Example 1 in that the modified polydopamine solution prepared in Preparation Example 4 is not added.

[0056] Comparative Example 5: The difference between this comparative example and Example 1 is that no transition bonding layer is added.

[0057] The performance test of the concrete conglomerate anticorrosive coatings prepared in Examples 1-6 and Comparative Examples 1-5 was conducted, and the results are shown in Table 1: The test method is as follows: Adhesion strength test: Tested in accordance with GB / T5210-2006 "Paint and varnish adhesion test by pull-off method"; Salt spray resistance test: The test is conducted in accordance with GB / T1771-2007 "Determination of resistance of paints and varnishes to neutral salt spray". The coating sample is continuously sprayed in 5% NaCl solution at 35°C for 1000 hours, and the coating surface is observed for rust, blistering, peeling, etc.

[0058] Weathering test: The test is conducted in accordance with GB / T1865-2009 "Paints and varnishes - Artificial weathering and artificial radiation exposure (filtered xenon arc radiation)". The coating samples are exposed to a xenon arc lamp aging test chamber with a cumulative radiation energy of 500kJ / m². The coating surface is observed for chalking, discoloration, cracking, etc.

[0059] Table 1

[0060] It can be seen from the performance tests of the above embodiments and comparative examples that the concrete gravel anti-corrosion coating prepared by the present invention has excellent adhesion, salt spray resistance and weather resistance, can effectively improve the anti-corrosion performance and durability of concrete gravel, and has a simple preparation process and low cost, and is suitable for large-scale promotion and application.

[0061] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A concrete conglomerate anti-corrosion coating, characterized in that: Including primer, transition bonding layer and top coating; The primer layer is made of the following raw materials in parts by weight: 50-70 parts of epoxy resin, 20-30 parts of curing agent, 5-10 parts of nanocomposite, 2-5 parts of silane coupling agent, 1-3 parts of dispersant, 30-50 parts of solvent; The transition bonding layer is made of the following raw materials in parts by weight: 40-50 parts of waterborne polyurethane resin, 10-15 parts of nano zinc oxide, and 5-10 parts of modified polydopamine solution; The topcoat is made of the following raw materials in parts by weight: 60-80 parts of acrylic resin, 20-30 parts of pigments and fillers, 1-3 parts of leveling agent, 1-3 parts of defoaming agent, 2-5 parts of preservative, and 40-60 parts of solvent.

2. The concrete conglomerate anti-corrosion coating according to claim 1, characterized in that: The preparation method of the nanocomposite comprises the following steps: S1. Take a 1.5 mg / mL graphene oxide dispersion, add 25% ammonia water, adjust the pH to 8.5-9.0, control stirring at 800-1000 r / min for 30-45 min, and add ethyl orthosilicate dropwise at a drop rate of 1 drop / second to ensure that ethyl orthosilicate evenly contacts the GO surface. Maintain the reaction temperature at 60-65°C and the reaction time for 3-4 h to obtain a silica-coated GO dispersion. During this period, use ammonia water to maintain the pH at 8.5-9.

5. S2. Add isopropyl tris(dioctyl pyrophosphate) titanate to a 3:1 ethanol / water mixture, add glacial acetic acid to adjust the pH to 4.5, and stir at room temperature for 30-40 minutes; S3, add the silica-coated GO dispersion obtained in S1 to the intermediate in S2, raise the temperature to 50-55°C, and stir the reaction for 6-8h; S4. After the reaction is completed, the precipitate is collected by centrifugation and washed with anhydrous ethanol 2-4 times to remove the unreacted coupling agent. The product is dried in a vacuum drying oven at 60-70°C for 10-12 hours and ground to obtain a powdered core-shell structure nanocomposite with a particle size of ≤100 nm.

3. The concrete conglomerate anti-corrosion coating according to claim 1, characterized in that: The curing agent is a phenalkamine epoxy curing agent; The silane coupling agent is one or more of 3-(2,3-epoxypropoxy)propyltriethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-aminopropyltriethoxysilane.

4. The concrete conglomerate anti-corrosion coating according to claim 1, characterized in that: The dispersant is one or more of polyacrylate sodium salt solution, polycarboxylate sodium salt solution, Dow 731A, BYK-155, BYK-190, and BYK-192.

5. The concrete conglomerate anti-corrosion coating according to claim 1, characterized in that: The solvent in the primer layer is toluene and / or xylene; the solvent in the topcoat layer is ethyl acetate.

6. The concrete conglomerate anti-corrosion coating according to claim 1, characterized in that: The pigment and filler are one or more of titanium dioxide, barium sulfate and talc.

7. The concrete conglomerate anti-corrosion coating according to claim 1, characterized in that: The leveling agent is one or more of BYK-331, BYK-333, BYK-378, and BASF EFKA FL 3772.

8. The concrete conglomerate anti-corrosion coating according to claim 1, characterized in that: The defoaming agent is a polydimethylsiloxane defoaming agent; and the preservative is 2-methyl-4-isothiazoline-3-one and / or 1,2-benzisothiazolin-3-one.

9. The concrete conglomerate anti-corrosion coating according to claim 1, characterized in that: The preparation method of the modified polydopamine solution comprises the following steps: 3-Aminophenylboronic acid and glycidyl methacrylate were added to anhydrous ethanol, and hydroquinone was added. Under nitrogen protection, the mixture was stirred at 60-65°C for 4-6 hours to obtain the functional monomer 3-APBA-GMA. Dopamine hydrochloride, functional monomer 3-APBA-GMA and tannic acid are added to a Tris-HCl buffer solution and stirred until completely dissolved. β-cyclodextrin is then added and stirred evenly. The solution is stirred and reacted at room temperature for 20-24 hours to obtain a modified polydopamine solution.

10. A method for preparing a concrete conglomerate anti-corrosion coating according to any one of claims 1 to 9, characterized in that: The following steps are also included: S1. Weigh the raw materials according to the weight parts, first add the epoxy resin and solvent into the reactor, stir evenly, then add the nanocomposite and dispersant, stir at a speed of 500-800 r / min for 30-60 min, then add the silane coupling agent and curing agent, and continue stirring for 10-20 min to obtain a primer; Apply the primer evenly by brushing or spraying it on the surface of the concrete gravel, with the coating thickness controlled at 50-100 μm, and then dry it at room temperature for 2-4 hours; S2, spraying the waterborne polyurethane resin, nano zinc oxide, and modified polydopamine solution onto the base coat to a thickness of 20-30 μm, and drying at 60° C. for 30 min to form a dense intermediate layer; S3, adding acrylic resin and solvent into the reaction kettle, stirring evenly, then adding pigments, fillers, leveling agents, defoaming agents and preservatives, stirring at a speed of 800-1000r / min for 60-90min until the materials are evenly mixed to obtain a topcoat liquid; The surface coating liquid is evenly brushed or sprayed on the surface of the concrete gravel after the dense middle layer is dried, the coating thickness is controlled at 100-150μm, and then dried at room temperature for 24-48h to obtain the concrete gravel anti-corrosion coating.

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