A concrete conglomerate anti-corrosion coating and its preparation method

Abstract

This invention pertains to the field of anti-corrosion coating technology, specifically relating to an anti-corrosion coating for concrete conglomerate and its preparation method. The coating comprises a base layer, a transition bonding layer, and a top layer. The base layer is made from the following raw materials in parts by weight: 50-70 parts epoxy resin, 20-30 parts curing agent, 5-10 parts nanocomposite, 2-5 parts silane coupling agent, 1-3 parts dispersant, and 30-50 parts solvent. The transition bonding layer is made from the following raw materials in parts by weight: 40-50 parts waterborne polyurethane resin, 10-15 parts nano zinc oxide, and 5-10 parts polydopamine solution with a concentration of 2-3 g / L. The top layer is made from the following raw materials in parts by weight: 60-80 parts acrylic resin, 20-30 parts pigments and fillers, 1-3 parts leveling agent, 1-3 parts defoamer, 2-5 parts preservative, and 40-60 parts solvent. This invention resolves the contradiction between flexibility and hardness in traditional coatings, significantly improves drying efficiency, and overcomes the defects of easy cracking and insufficient adhesion in existing technologies. It has significant technological advancements and industrial application value.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology, and in particular to an anti-corrosion coating for concrete conglomerate and its preparation method. Background Technology

[0002] Concrete conglomerate is a commonly used material in construction engineering, widely used in infrastructure construction such as bridges, tunnels, ports, and water conservancy facilities. However, concrete conglomerate is exposed to the external environment for a long time and 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 lead to structural damage and reduced strength of concrete conglomerate, thereby affecting the safety and durability of the entire building structure.

[0003] Currently, to improve the corrosion resistance of concrete conglomerate, anti-corrosion coatings are typically applied to its surface. Many types of anti-corrosion coatings are 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 lack 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 anti-corrosion performance. Furthermore, existing anti-corrosion coating preparation methods are relatively complex and costly, and the bonding strength between the coating and the concrete conglomerate surface is not ideal, easily leading to peeling and detachment, thus affecting the anti-corrosion effect.

[0004] Therefore, there is an urgent need for a method to prepare an anti-corrosion coating that is simple to manufacture, low in cost, has excellent anti-corrosion performance, and strong adhesion to concrete conglomerate surfaces. Summary of the Invention

[0005] To address the problems mentioned in the background section, this invention provides a concrete conglomerate anti-corrosion coating and its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A concrete conglomerate anti-corrosion coating includes a primer, a transition bonding layer, and a topcoat, wherein the primer is made from the following raw materials in parts by weight:

[0008] 50-70 parts epoxy resin, 20-30 parts curing agent, 5-10 parts nanocomposite, 2-5 parts silane coupling agent, 1-3 parts dispersant, 30-50 parts solvent;

[0009] The transition adhesive layer is made from the following raw materials in parts by weight:

[0010] 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 2-3 g / L;

[0011] The preparation method of the modified polydopamine solution includes the following steps:

[0012] 3-Aminophenylboronic acid and glycidyl methacrylate were added to anhydrous ethanol, followed by hydroquinone. The mixture was stirred and reacted at 60-65°C for 4-6 hours under nitrogen protection to obtain the functional monomer 3-APBA-GMA.

[0013] Weigh out dopamine hydrochloride, 3-APBA-GMA and tannic acid, add them to Tris-HCl buffer solution (pH=8.5, 10mmol / L), stir until completely dissolved, then add β-cyclodextrin, stir evenly, and stir the solution at room temperature for 20-24h to obtain modified polydopamine solution.

[0014] By pre-synthesizing the functional monomer 3-APBA-GMA, which contains borate ester bonds and epoxy groups, the dynamic covalent bonds of borate esters and the active epoxy groups are introduced into the molecular structure of polydopamine. The borate ester bonds exhibit pH responsiveness and dynamic reversibility, remaining stable in alkaline environments while undergoing reversible breakage and recombination in acidic environments, thus endowing the material with self-healing capabilities. The epoxy groups can undergo ring-opening reactions with the hydroxyl groups on the surface of concrete conglomerate, enhancing the chemical bonding between the coating and the substrate and significantly improving adhesion performance.

[0015] This transitional bonding layer forms hydrogen and covalent bonds with the concrete surface through the catechol groups of dopamine, while simultaneously forming an interpenetrating network structure with the primer epoxy resin. The catechol groups of polydopamine form coordination bonds with iron / calcium ions on the concrete surface, and react with the isocyanate groups of waterborne polyurethane to generate urea bonds, forming a 5-10 μm transition layer between the primer and the substrate. This significantly reduces the modulus gradient of the coating system and substantially reduces interfacial stress concentration.

[0016] The surface coating is made from the following raw materials in parts by weight:

[0017] Acrylic resin 60-80 parts, pigments and fillers 20-30 parts, leveling agent 1-3 parts, defoamer 1-3 parts, preservative 2-5 parts, solvent 40-60 parts.

[0018] Preferably, the preparation method of the nanocomposite includes the following steps:

[0019] S1. Take a 1.5 mg / mL graphene oxide dispersion, add 25% ammonia water, adjust the pH to 8.5-9.0, stir at 800-1000 r / min for 30-45 min, and add tetraethyl orthosilicate dropwise at a rate of 1 drop / second to ensure uniform contact of tetraethyl orthosilicate with the GO surface. Maintain the reaction temperature at 60-65℃ and the reaction time at 3-4 h to obtain a silica-coated GO dispersion. During this period, maintain the pH at 8.5-9.5 with ammonia water (check every 30 min).

[0020] Tetraethyl orthosilicate first hydrolyzes under alkaline conditions to generate Si(OH)4, which then condenses to form a -Si-O-Si- network. The hydroxyl sites on the GO surface are adsorbed through hydrogen bonding, and a silica shell with a thickness of 5-10 nm is gradually deposited.

[0021] S2. Add isopropyl tris(dioctyl pyrophosphoryloxy) titanate to a 3:1 volume ratio ethanol / water mixture, add glacial acetic acid to adjust the pH to 4.5, stir at room temperature for 30-40 min to hydrolyze isopropyl tris(dioctyl pyrophosphoryloxy) titanate to generate an intermediate containing active titanium hydroxyl groups (-TiOH).

[0022] S3. Add the silica-coated GO dispersion obtained in S1 to the intermediate in S2, heat to 50-55℃, and stir for 6-8 hours.

[0023] The isopropyltris(dioctylpyrophosphonoyloxy) titanate molecule contains an easily hydrolyzed alkoxy group. In an ethanol / water mixture under acidic conditions, it undergoes hydrolysis to generate an intermediate containing an active titanium hydroxyl group (-TiOH). Ethanol / water serves as a solvent, ensuring both the solubility of the coupling agent and providing the necessary aqueous environment for hydrolysis.

[0024] S4. After the reaction is complete, the precipitate is collected by centrifugation and washed 2-4 times with anhydrous ethanol to remove unreacted coupling agent. The product is dried in a vacuum drying oven at 60-70℃ for 10-12 hours and then ground to obtain a core-shell structured complex in powder form with a particle size ≤100nm.

[0025] Preferably, the curing agent is a phenolic amine epoxy curing agent.

[0026] 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).

[0027] Preferably, the dispersant is one or more of sodium polyacrylate solution, sodium polycarboxylate solution, Dow 731A, BYK-155, BYK-190, and BYK-192.

[0028] Preferably, the solvent in the base coating is toluene and / or xylene.

[0029] Preferably, the solvent in the surface coating is ethyl acetate.

[0030] Preferably, the pigment or filler is one or more of titanium dioxide, barium sulfate, and talc.

[0031] Preferably, the leveling agent is one or more of BYK-331, BYK-333, BYK-378, and BASF EFKA FL3772.

[0032] Preferably, the defoamer is a polydimethylsiloxane defoamer.

[0033] Preferably, the preservative is 2-methyl-4-isothiazolin-3-one and / or 1,2-benzisothiazolin-3-one.

[0034] A method for preparing a concrete conglomerate anti-corrosion coating further includes the following steps:

[0035] S1. Weigh the raw materials according to the stated weight proportions, first add the epoxy resin and solvent to the reaction vessel and 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 the primer liquid.

[0036] Apply the primer evenly to the concrete conglomerate surface by brushing or spraying, with the coating thickness controlled at 50-100μm, and then dry at room temperature for 2-4 hours.

[0037] S2. The waterborne polyurethane resin, nano zinc oxide and modified polydopamine solution are mixed and sprayed onto the base layer. The coating thickness is 20-30μm. The mixture is dried at 60℃ for 30min to form a dense intermediate layer.

[0038] S3. Add acrylic resin and solvent to the reaction vessel and stir evenly. Then add pigments, fillers, leveling agents, defoamers and preservatives. Stir at 800-1000 r / min for 60-90 min until the materials are evenly mixed to obtain the topcoat liquid.

[0039] After the dense intermediate layer has dried, a topcoat is evenly brushed or sprayed onto the concrete conglomerate surface, with the coating thickness controlled at 100-150μm. Then, it is dried at room temperature for 24-48 hours to obtain the concrete conglomerate anti-corrosion coating.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. This invention doubles the salt spray resistance time of the coating and increases the electrical 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 flexibility and hardness in traditional coatings, greatly improves drying efficiency, and overcomes the defects of easy cracking and insufficient bonding in existing technologies. It has significant technological progress and industrial application value.

[0042] 2. This invention establishes a transitional bonding layer by forming hydrogen and covalent bonds between the catechol groups of dopamine and the concrete surface, while simultaneously forming an interpenetrating network structure with the primer epoxy resin. The catechol groups of polydopamine form coordination bonds with iron / calcium ions on the concrete surface, and react with the isocyanate groups of waterborne polyurethane to generate urea bonds, forming a 5-10 μm transition layer between the primer and the substrate. This significantly reduces the modulus gradient of the coating system and substantially reduces interfacial stress concentration. Detailed Implementation

[0043] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Unless otherwise specified, the raw materials used in this invention are all from commercially available conventional products.

[0045] The epoxy resin was purchased from Shandong Jinhong New Material Technology Co., Ltd., item number 11212;

[0046] The waterborne polyurethane resin was purchased from Hunan Yoshida New Technology Co., Ltd., model number RY8402.

[0047] The nano zinc oxide was purchased from Nanjing Baoket New Materials Co., Ltd., CAS number 1314-13-2;

[0048] The graphene oxide dispersion was purchased from KERI Nano (Guangdong) Co., Ltd., CAS No. 7782-42-5.

[0049] Preparation Example 1: The preparation method of the nanocomposite includes the following steps:

[0050] 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, stir 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 rate of 1 drop / second to ensure that the tetraethyl orthosilicate is uniformly in contact with the GO surface. Maintain the reaction temperature at 60℃ and the reaction time at 3 h to obtain a silica-coated GO dispersion. During this period, the pH is maintained at 8.5 with ammonia water (checked every 30 min).

[0051] S2. Add 2 mL of isopropyl tris(dioctyl pyrophosphoryloxy) titanate to 20 mL of a 3:1 volume ratio ethanol / water mixture, add 0.1 mL of glacial acetic acid to adjust the pH to 4.5, stir at room temperature for 30 min to hydrolyze isopropyl tris(dioctyl pyrophosphoryloxy) titanate to generate an intermediate containing an active titanium hydroxyl group (-TiOH).

[0052] S3. Add the silica-coated GO dispersion obtained in S1 to the intermediate in S2, heat to 50°C, and stir for 6 hours.

[0053] S4. After the reaction is complete, the precipitate is collected by centrifugation, washed twice with anhydrous ethanol to remove unreacted coupling agent, and the product is dried in a vacuum drying oven at 60℃ for 10h. The product is then ground to obtain a powdered core-shell structured complex with a particle size ≤100nm.

[0054] Preparation Example 2: The preparation method of the nanocomposite includes the following steps:

[0055] 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, stir 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 rate of 1 drop / second to ensure that the tetraethyl orthosilicate is uniformly in contact with the GO surface. Maintain the reaction temperature at 62℃ and the reaction time at 3 h to obtain a silica-coated GO dispersion. During this period, the pH is maintained at 9.0 with ammonia water (checked every 30 min).

[0056] S2. Add 2 mL of isopropyl tris(dioctyl pyrophosphoryloxy) titanate to 20 mL of a 3:1 volume ratio ethanol / water mixture, add 0.1 mL of glacial acetic acid to adjust the pH to 4.5, stir at room temperature for 35 min to hydrolyze isopropyl tris(dioctyl pyrophosphoryloxy) titanate to generate an intermediate containing an active titanium hydroxyl group (-TiOH).

[0057] S3. Add the silica-coated GO dispersion obtained in S1 to the intermediate in S2, heat to 55°C, and stir for 7 hours.

[0058] S4. After the reaction is complete, the precipitate is collected by centrifugation, washed three times with anhydrous ethanol to remove unreacted coupling agent, and the product is dried in a vacuum drying oven at 65°C for 11 hours. The product is then ground to obtain a powdered core-shell structured composite with a particle size ≤100nm.

[0059] Preparation Example 3: The preparation method of the nanocomposite includes the following steps:

[0060] 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, stir at 1000 r / min for 45 min, and add 2 mL of tetraethyl orthosilicate (pre-dissolved in 5 mL of anhydrous ethanol) dropwise at a rate of 1 drop / second to ensure that the tetraethyl orthosilicate is uniformly in contact with the GO surface. Maintain the reaction temperature at 65℃ and the reaction time at 4 h to obtain a silica-coated GO dispersion. During this period, the pH is maintained at 9.5 with ammonia water (checked every 30 min).

[0061] S2. Add 2 mL of isopropyl tris(dioctyl pyrophosphoryl oxy) titanate to 20 mL of a 3:1 volume ratio ethanol / water mixture, add 0.1 mL of glacial acetic acid to adjust the pH to 4.5, stir at room temperature for 40 min to hydrolyze isopropyl tris(dioctyl pyrophosphoryl oxy) titanate to generate an intermediate containing an active titanium hydroxyl group (-TiOH).

[0062] S3. Add the silica-coated GO dispersion obtained in S1 to the intermediate in S2, heat to 55°C, and stir for 8 hours.

[0063] S4. After the reaction is complete, the precipitate is collected by centrifugation, washed four times with anhydrous ethanol to remove unreacted coupling agent, and the product is dried in a vacuum drying oven at 70°C for 12 hours. The product is then ground to obtain a powdered core-shell structured composite with a particle size ≤100nm.

[0064] Preparation Example 4: The preparation method of the modified polydopamine solution includes the following steps:

[0065] 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. The mixture was stirred at 65 °C for 6 h under nitrogen protection to obtain the functional monomer 3-APBA-GMA.

[0066] Weigh 2g of dopamine hydrochloride, 0.5g of 3-APBA-GMA and 0.3g of tannic acid, add them to 100mL of Tris-HCl buffer solution (pH=8.5, 10mmol / L), stir until completely dissolved, then add 0.1g of β-cyclodextrin, stir evenly and let the solution react at room temperature for 24h to obtain modified polydopamine solution.

[0067] Example 1: A method for preparing a concrete conglomerate anti-corrosion coating, further comprising the following steps:

[0068] S1. First, add 50 parts of epoxy resin and 40 parts of toluene to the reaction vessel and stir evenly. Then, add 5 parts of the nanocomposite prepared in Preparation Example 1 and 2 parts of sodium polyacrylate solution. Stir at 500 r / min for 60 min. Then, add 2 parts of silane coupling agent KH-561 and 20 parts of phenolic amine epoxy curing agent. Continue stirring for 10 min to obtain the primer.

[0069] Apply the primer evenly to the concrete conglomerate surface by brushing or spraying, with the coating thickness controlled at 50 μm, and then dry at room temperature for 2 hours.

[0070] S2. Mix the 40 parts of waterborne polyurethane resin, 15 parts of nano zinc oxide, and 5 parts of the modified polydopamine solution prepared in Preparation Example 4 with a concentration of 2 g / L, and spray the mixture onto the base layer. The coating thickness is 20 μm. Dry at 60°C for 30 min to form a dense intermediate layer.

[0071] S3. Add 60 parts of acrylic resin and 40 parts of ethyl acetate to the reactor and stir until homogeneous. Then add 20 parts of titanium dioxide, 1 part of BYK-331, 1 part of polydimethylsiloxane defoamer, and 3 parts of 2-methyl-4-isothiazolin-3-one. Stir at 800 rpm for 60 minutes until the materials are uniformly mixed to obtain the topcoat liquid.

[0072] After the dense intermediate layer has dried, a topcoat is evenly brushed or sprayed onto the concrete conglomerate surface, with the coating thickness controlled at 100 μm. Then, it is dried at room temperature for 24 hours to obtain the concrete conglomerate anti-corrosion coating.

[0073] Example 2: A method for preparing a concrete conglomerate anti-corrosion coating, further comprising the following steps:

[0074] S1. First, add 60 parts of epoxy resin and 35 parts of xylene to the reactor and stir evenly. Then add 6 parts of the nanocomposite prepared in Preparation Example 2 and 2 parts of BYK-155. Stir at 600 r / min for 50 min. Then add 2 parts of silane coupling agent KH-580 and 25 parts of phenolic amine epoxy curing agent. Continue stirring for 15 min to obtain the primer.

[0075] Apply the primer evenly to the concrete conglomerate surface by brushing or spraying, with the coating thickness controlled at 70 μm, and then dry at room temperature for 3 hours.

[0076] S2. Mix the 45 parts of waterborne polyurethane resin, 12 parts of nano zinc oxide, and 7 parts of the modified polydopamine solution prepared in Preparation Example 4 with a concentration of 2.5 g / L, and spray the mixture onto the base layer. The coating thickness is 25 μm. Dry at 60°C for 30 min to form a dense intermediate layer.

[0077] S3. Add 60 parts of acrylic resin and 60 parts of ethyl acetate to the reactor and stir until homogeneous. 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. Stir at 900 rpm for 80 minutes until the materials are uniformly mixed to obtain the topcoat solution.

[0078] After the dense intermediate layer has dried, a topcoat is evenly brushed or sprayed onto the concrete conglomerate surface, with the coating thickness controlled at 120 μm. Then, it is dried at room temperature for 30 hours to obtain the concrete conglomerate anti-corrosion coating.

[0079] Example 3: A method for preparing a concrete conglomerate anti-corrosion coating, further comprising the following steps:

[0080] S1. First, add 70 parts of epoxy resin and 50 parts of xylene to the reaction vessel and stir evenly. Then, add 10 parts of the nanocomposite prepared in Preparation Example 3 and 2 parts of BYK-192. Stir at 800 r / min for 60 min. Then, add 5 parts of silane coupling agent KH-550 and 20 parts of phenolic amine epoxy curing agent. Continue stirring for 20 min to obtain the primer.

[0081] Apply the primer evenly to the concrete conglomerate surface by brushing or spraying, with the coating thickness controlled at 100 μm, and then dry at room temperature for 4 hours.

[0082] S2. Mix the 50 parts of waterborne polyurethane resin, 15 parts of nano zinc oxide, and 5 parts of the modified polydopamine solution prepared in Preparation Example 4 with a concentration of 3 g / L, and spray the mixture onto the base layer. The coating thickness is 30 μm. Dry at 60°C for 30 min to form a dense intermediate layer.

[0083] S3. Add 80 parts of acrylic resin and 40 parts of ethyl acetate to the reactor and stir until homogeneous. Then add 30 parts of talc powder, 3 parts of BASF EFKA FL 3772, 3 parts of polydimethylsiloxane defoamer, and 5 parts of 2-methyl-4-isothiazolin-3-one. Stir at 1000 rpm for 90 minutes until the materials are uniformly mixed to obtain the topcoat liquid.

[0084] After the dense intermediate layer has dried, a topcoat is evenly brushed or sprayed onto the concrete conglomerate surface, with the coating thickness controlled at 150 μm. Then, it is dried at room temperature for 48 hours to obtain the concrete conglomerate anti-corrosion coating.

[0085] Example 4: A method for preparing a concrete conglomerate anti-corrosion coating, further comprising the following steps:

[0086] S1. First, add 50 parts of epoxy resin and 40 parts of xylene to the reaction vessel and stir evenly. Then, add 5 parts of the nanocomposite prepared in Preparation Example 2 and 2 parts of sodium polyacrylate solution. Stir at 500 r / min for 60 min. Then, add 2 parts of silane coupling agent KH-580 and 20 parts of phenolic amine epoxy curing agent. Continue stirring for 10 min to obtain the primer.

[0087] Apply the primer evenly to the concrete conglomerate surface by brushing or spraying, with the coating thickness controlled at 50 μm, and then dry at room temperature for 2 hours.

[0088] S2. Mix the 40 parts of waterborne polyurethane resin, 15 parts of nano zinc oxide, and 5 parts of the modified polydopamine solution prepared in Preparation Example 4 with a concentration of 2 g / L, and spray the mixture onto the base layer. The coating thickness is 20 μm. Dry at 60°C for 30 min to form a dense intermediate layer.

[0089] S3. Add 60 parts of acrylic resin and 40 parts of ethyl acetate to the reactor and stir until homogeneous. Then add 20 parts of titanium dioxide, 1 part of BYK-378, 1 part of polydimethylsiloxane defoamer, and 3 parts of 2-methyl-4-isothiazolin-3-one. Stir at 800 rpm for 60 minutes until the materials are uniformly mixed to obtain the topcoat liquid.

[0090] After the dense intermediate layer has dried, a topcoat is evenly brushed or sprayed onto the concrete conglomerate surface, with the coating thickness controlled at 110 μm. Then, it is dried at room temperature for 35 hours to obtain the concrete conglomerate anti-corrosion coating.

[0091] Example 5: A method for preparing a concrete conglomerate anti-corrosion coating, further comprising the following steps:

[0092] S1. First, add 60 parts of epoxy resin and 35 parts of xylene to the reactor and stir evenly. Then add 6 parts of the nanocomposite prepared in Preparation Example 1 and 2 parts of BYK-192. Stir at 700 r / min for 60 min. Then add 2 parts of silane coupling agent KH-580 and 25 parts of phenolic amine epoxy curing agent. Continue stirring for 20 min to obtain the primer.

[0093] Apply the primer evenly to the concrete conglomerate surface by brushing or spraying, with the coating thickness controlled at 90 μm, and then dry at room temperature for 3 hours.

[0094] S2. Mix the 45 parts of waterborne polyurethane resin, 12 parts of nano zinc oxide, and 7 parts of the modified polydopamine solution prepared in Preparation Example 4 with a concentration of 3 g / L, and spray the mixture onto the base layer. The coating thickness is 25 μm. Dry at 60°C for 30 min to form a dense intermediate layer.

[0095] S3. Add 60 parts of acrylic resin and 60 parts of ethyl acetate to the reactor and stir until homogeneous. Then add 30 parts of barium sulfate, 1 part of BYK-333, 1 part of polydimethylsiloxane defoamer and 2 parts of 2-methyl-4-isothiazolin-3-one. Stir at 900 r / min for 80 min until the materials are mixed evenly to obtain the topcoat liquid.

[0096] After the dense intermediate layer has dried, a topcoat is evenly brushed or sprayed onto the concrete conglomerate surface, with the coating thickness controlled at 100 μm. Then, it is dried at room temperature for 30 hours to obtain the concrete conglomerate anti-corrosion coating.

[0097] Example 6: A method for preparing a concrete conglomerate anti-corrosion coating, further comprising the following steps:

[0098] S1. First, add 70 parts of epoxy resin and 50 parts of xylene to the reactor and stir evenly. Then, add 10 parts of the nanocomposite prepared in Preparation Example 2 and 2 parts of Dow 731A. Stir at 750 r / min for 55 min. Then, add 5 parts of silane coupling agent KH-550 and 20 parts of phenolic amine epoxy curing agent. Continue stirring for 15 min to obtain the primer.

[0099] Apply the primer evenly to the concrete conglomerate surface by brushing or spraying, with the coating thickness controlled at 90 μm, and then dry at room temperature for 4 hours.

[0100] S2. Mix the 50 parts of waterborne polyurethane resin, 15 parts of nano zinc oxide, and 5 parts of the modified polydopamine solution prepared in Preparation Example 4 with a concentration of 3 g / L, and spray the mixture onto the base layer. The coating thickness is 30 μm. Dry at 60°C for 30 min to form a dense intermediate layer.

[0101] S3. Add 80 parts of acrylic resin and 40 parts of ethyl acetate to the reactor and stir until homogeneous. Then add 30 parts of talc powder, 3 parts of BASF EFKA FL 3772, 3 parts of polydimethylsiloxane defoamer, and 5 parts of 2-methyl-4-isothiazolin-3-one. Stir at 900 rpm for 70 minutes until the materials are uniformly mixed to obtain the topcoat liquid.

[0102] After the dense intermediate layer has dried, a topcoat is evenly brushed or sprayed onto the concrete conglomerate surface, with the coating thickness controlled at 120 μm. Then, it is dried at room temperature for 40 hours to obtain the concrete conglomerate anti-corrosion coating.

[0103] Comparative Example 1: The difference between this comparative example and Example 1 is that the nanocomposite prepared in Example 1 was replaced with nano-silica, which was purchased from Hubei Huifu E-commerce Co., Ltd.

[0104] Comparative Example 2: The difference between this comparative example and Example 1 is that the nanocomposite prepared in Example 1 was replaced with graphene oxide, which was purchased from Sichuan Kenye Technology Development Co., Ltd., model number KY CRG1210.

[0105] Comparative Example 3: The difference between this comparative example and Example 1 is that tetraethyl orthosilicate was not added during the preparation of the nanocomposite in Example 1.

[0106] Comparative Example 4: The difference between this comparative example and Example 1 is that the modified polydopamine solution prepared in Example 4 was not added.

[0107] Comparative Example 5: The difference between this comparative example and Example 1 is that no transition adhesive layer is added.

[0108] The performance of the concrete conglomerate anti-corrosion coatings prepared in Examples 1-6 and Comparative Examples 1-5 was tested, and the results are shown in Table 1:

[0109] The testing method is as follows:

[0110] Adhesion strength test: The test shall be conducted in accordance with GB / T5210-2006 "Paints and Varnishes - Pull-off Adhesion Test".

[0111] Salt spray resistance test: The test was conducted in accordance with GB / T1771-2007 "Determination of resistance to neutral salt spray of paints and varnishes". The coating sample was continuously sprayed in 5% NaCl solution at 35℃ for 1000h, and the coating surface was observed for rust, blistering, peeling and other phenomena.

[0112] Weather resistance test: The test was conducted in accordance with GB / T1865-2009 "Artificial weathering and artificial radiation exposure (filtered xenon arc radiation) of paints and varnishes". The coating sample was exposed to a xenon arc lamp aging test chamber with a cumulative radiation energy of 500kJ / m². The coating surface was observed to see if there were any phenomena such as chalking, discoloration, or cracking.

[0113] Table 1

[0114]

[0115] The performance tests of the above embodiments and comparative examples show that the anti-corrosion coating for concrete conglomerate prepared by the present invention has excellent adhesion, salt spray resistance and weather resistance, which can effectively improve the anti-corrosion performance and durability of concrete conglomerate. Moreover, the preparation process is simple and low in cost, making it suitable for large-scale promotion and application.

[0116] 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, Includes a base coat, a transition adhesive layer, and a top coat; The base coating is made from the following raw materials in parts by weight: 50-70 parts epoxy resin, 20-30 parts curing agent, 5-10 parts nanocomposite, 2-5 parts silane coupling agent, 1-3 parts dispersant, 30-50 parts solvent; The transition adhesive layer is made 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 modified polydopamine solution; The surface coating is made from the following raw materials in parts by weight: Acrylic resin 60-80 parts, pigments and fillers 20-30 parts, leveling agent 1-3 parts, defoamer 1-3 parts, preservative 2-5 parts, solvent 40-60 parts; The preparation method of the nanocomposite includes 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, stir at 800-1000 r / min for 30-45 min, and add tetraethyl orthosilicate dropwise at a rate of 1 drop / second to ensure uniform contact of tetraethyl orthosilicate with the GO surface. Maintain the reaction temperature at 60-65℃ and the reaction time at 3-4 h to obtain a silica-coated GO dispersion. During this process, maintain the pH at 8.5-9.5 with ammonia water. S2. Add isopropyl tris(dioctylpyrophosphoryloxy)titanate to a 3:1 volume ratio 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, heat to 50-55℃, and stir for 6-8 hours. S4. After the reaction is complete, the precipitate is collected by centrifugation and washed 2-4 times with anhydrous ethanol to remove unreacted coupling agent. The product is dried in a vacuum drying oven at 60-70℃ for 10-12 hours and then ground to obtain a core-shell structured nanocomposite with a particle size ≤100nm. The preparation method of the modified polydopamine solution includes the following steps: 3-Aminophenylboronic acid and glycidyl methacrylate were added to anhydrous ethanol, hydroquinone was added, and the mixture was stirred at 60-65℃ for 4-6 hours under nitrogen protection to obtain the functional monomer 3-APBA-GMA. Dopamine hydrochloride, the functional monomer 3-APBA-GMA, and tannic acid were added to a Tris-HCl buffer solution and stirred until completely dissolved. Then, β-cyclodextrin was added and stirred until homogeneous. The solution was then stirred at room temperature for 20-24 hours to obtain a modified polydopamine solution.

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

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

4. The anti-corrosion coating for concrete conglomerate according to claim 1, characterized in that, The solvent in the base coating is toluene and / or xylene; the solvent in the top coating is ethyl acetate.

5. The anti-corrosion coating for concrete conglomerate according to claim 1, characterized in that, The pigments and fillers are one or more of titanium dioxide, barium sulfate, and talc.

6. The anti-corrosion coating for concrete conglomerate 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.

7. The anti-corrosion coating for concrete conglomerate according to claim 1, characterized in that, The defoamer is a polydimethylsiloxane defoamer; the preservative is 2-methyl-4-isothiazolin-3-one and / or 1,2-benzisothiazolin-3-one.

8. A method for preparing a concrete conglomerate anti-corrosion coating as described in any one of claims 1-7, characterized in that, It also includes the following steps: S1. Weigh the raw materials according to the stated weight proportions, first add the epoxy resin and solvent to the reaction vessel and 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 the primer liquid. Apply the primer evenly to the concrete conglomerate surface by brushing or spraying, with the coating thickness controlled at 50-100μm, and then dry at room temperature for 2-4 hours. S2. The waterborne polyurethane resin, nano zinc oxide and modified polydopamine solution are mixed and sprayed onto the base layer. The coating thickness is 20-30μm. The mixture is dried at 60℃ for 30min to form a dense intermediate layer. S3. Add acrylic resin and solvent to the reaction vessel and stir evenly. Then add pigments, fillers, leveling agents, defoamers and preservatives. Stir at 800-1000 r / min for 60-90 min until the materials are evenly mixed to obtain the topcoat liquid. After the dense intermediate layer has dried, a topcoat is evenly brushed or sprayed onto the concrete conglomerate surface, with the coating thickness controlled at 100-150μm. Then, it is dried at room temperature for 24-48 hours to obtain the concrete conglomerate anti-corrosion coating.

Images