Steel grating plate composite anticorrosive coating and preparation method thereof

Abstract

The invention discloses a preparation method of a composite anticorrosive coating of a steel grating plate, which comprises the following steps: S1, carrying out spinning operation by adopting a self-repairing polymer solution to form hollow fibers with a hollow structure; s2, the hollow fibers are soaked in corrosion inhibition liquid with ethyl alcohol as a solvent, the hollow fibers are filled with the corrosion inhibition liquid, and then end sealing treatment is conducted; s3, performing heat treatment to form hollow fibers with a porous structure; s4, coating a layer of pH response type polymer on the surface of the substrate; and S5, mixing with an anti-corrosion coating, then spraying on the surface of the steel grating plate, and curing to obtain the composite anti-corrosion coating. According to the preparation method disclosed by the invention, the self-repairing function of the coating is realized, the corrosion resistance of the coating in an acid environment is enhanced, the durability and adaptability of the coating are improved through an intelligent response mechanism, and the long-term stable use requirements in high-corrosion environments such as ocean and chemical engineering can be met.

Description

Technical Field

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

[0002] As a commonly used industrial material, steel grating is widely used in construction, chemical industry, marine and other fields. However, during use, steel grating is susceptible to corrosion, especially in environments with high humidity, high salinity and strong chemical corrosion, and its service life will be significantly shortened. Especially in acidic environments, the corrosion rate is further accelerated, and the protective performance of traditional anti-corrosion coatings is greatly reduced. Traditional anti-corrosion coatings mainly prevent corrosion of metal surfaces through physical isolation and chemical protection, but these coatings are prone to cracks or breakage when subjected to mechanical impact or chemical erosion, resulting in coating failure. In addition, traditional coatings lack self-repairing functions. Once damaged, the corrosive medium will quickly penetrate into the metal surface, further exacerbating corrosion. Therefore, it is of great practical significance to develop a new anti-corrosion coating that can effectively solve these problems to improve the corrosion resistance and service life of steel grating in harsh environments such as acidic environments. Summary of the Invention

[0003] In view of the above shortcomings of the existing technology, the present invention provides a method for preparing a composite anti-corrosion coating for steel grating plates to solve technical problems such as the traditional anti-corrosion coating being prone to failure in highly corrosive environments, lacking self-repairing function and having insufficient mechanical properties.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is: A method for preparing a composite anti-corrosion coating for a steel grating, the method comprising the following steps: S1: A self-repairing polymer solution is used for spinning operation to form a hollow fiber with a hollow structure; the length of the hollow fiber is 5 to 10 mm, and the pore size is 1 to 10 μm; step S1 of the present application prepares a fiber with a hollow structure by spinning with a self-repairing polymer solution. This hollow fiber not only has good mechanical properties and can enhance the impact resistance and wear resistance of the coating, but also its internal hollow structure can serve as a storage space for corrosion inhibitors and antibacterial agents, providing a basis for subsequent self-repair functions. The length and pore size of the hollow fiber are reasonably designed to ensure uniform distribution and effective release of the internal filling material while ensuring fiber strength. When the coating is damaged, the repair material inside the hollow fiber can be activated, thereby realizing the self-repair function of the coating and significantly improving the durability and stability of the coating.

[0005] S2: Soak the hollow fiber obtained in step S1 in a corrosion inhibitor with ethanol as the solvent, so that the corrosion inhibitor is filled into the interior of the hollow fiber, and then perform end-capping treatment on the hollow fiber; Step S2 of the present application soaks the hollow fiber in a corrosion inhibitor with ethanol as the solvent, so that the corrosion inhibitor can be fully filled into the interior of the hollow fiber. Ethanol as a solvent has good solubility and volatility, and can evaporate quickly during the subsequent heat treatment process to form a porous structure, providing space for the storage and release of the corrosion inhibitor. The end-capping treatment ensures the stability of the corrosion inhibitor inside the hollow fiber and prevents it from being lost prematurely during the coating preparation and storage process. This design allows the corrosion inhibitor to be evenly released through the porous structure of the hollow fiber when the coating is damaged, forming a protective film, effectively inhibiting the corrosion of the metal surface, thereby significantly improving the anti-corrosion performance of the coating.

[0006] S3: The hollow fibers filled and capped in step S2 are heat-treated to volatilize ethanol from the fiber surface, forming a hollow fiber with a porous structure. In step S3 of the present application, ethanol evaporates from the fiber surface through the heat treatment process, forming a porous structure inside the hollow fiber. This porous structure not only provides more storage space for the corrosion inhibitor, but also promotes the rapid release of the corrosion inhibitor when needed. At the same time, the heat treatment process also enhances the structural stability of the hollow fiber, allowing it to maintain good performance during subsequent coating preparation and use.

[0007] S4: Coating the surface of the hollow fiber that has been heat-treated in step S3 with a layer of pH-responsive polymer; Step S4 of the present application coats the surface of the hollow fiber with a layer of pH-responsive polymer, providing an intelligent response mechanism for the coating. This polymer can rapidly degrade in an acidic environment, releasing the corrosion inhibitors and antibacterial agents stored inside the hollow fiber. When the coating is corroded by the corrosive medium and the local environment becomes acidic, the pH-responsive polymer automatically responds, activates the self-repair process, and realizes timely repair of the damaged parts. This intelligent response mechanism not only improves the self-repair efficiency of the coating, but also can self-regulate according to the actual conditions of the corrosive environment, thereby significantly improving the durability and stability of the coating. At the same time, the coating of the pH-responsive polymer can also improve the surface properties of the hollow fiber, enhance its bonding with the anti-corrosion coating, and improve the overall performance of the coating.

[0008] S5: Mix the hollow fibers coated in step S4 with the anti-corrosion coating, then spray them on the surface of the steel grating, and perform a curing treatment to prepare the composite anti-corrosion coating. The composite anti-corrosion coating prepared in step S5 of the present application not only retains the excellent properties of traditional anti-corrosion coatings, such as good adhesion, wear resistance and weather resistance, but also gives the coating a self-repairing function through the addition of hollow fibers. The hollow fibers are evenly distributed in the coating and can quickly respond and release repair materials when the coating is damaged, thereby achieving self-repair of the coating. The curing treatment ensures the structural stability and mechanical properties of the coating, enabling it to withstand various environmental factors in actual use. The final composite anti-corrosion coating has excellent comprehensive performance, can effectively extend the service life of the steel grating, and reduce maintenance costs.

[0009] As a preferred technical solution, the self-healing polymer solution includes the following raw materials in parts by weight: 10 to 30 parts of disulfide bond modified polyurethane, 20 to 40 parts of epoxy resin, 5 to 15 parts of nano zinc oxide, 1 to 10 parts of corrosion inhibitor, 1 to 10 parts of antibacterial agent, 1 to 5 parts of plasticizer and 1 to 5 parts of stabilizer.

[0010] As a preferred technical solution, the disulfide bond modified polyurethane is obtained by reacting a polyurethane prepolymer containing at least two isocyanate end groups with N,N'-bis(2-hydroxyethyl)dithioacetamide.

[0011] The parameters of the spinning operation are: spinning voltage 15-25 kV, spinning distance 15-25 cm, and flow rate 0.5-1.5 mL / h.

[0012] As a preferred technical solution, the corrosion inhibition solution further includes an amine curing agent, a corrosion inhibitor and an organic antibacterial agent.

[0013] As a preferred technical solution, the amine curing agent is at least one of a phenolic amine curing agent, an alicyclic amine curing agent and a fatty amine curing agent.

[0014] As a preferred technical solution, the corrosion inhibitor is at least one of benzotriazole, methylbenzotriazole, and 2-mercaptobenzothiazole.

[0015] As a preferred technical solution, the organic antibacterial agent consists of isothiazolinone and polyhexamethyleneguanidine.

[0016] As a preferred technical solution, the end-capping treatment is to use a chemical end-capping agent to block both ends of the hollow fiber, and the chemical end-capping agent is a silane coupling agent and / or an epoxy resin end-capping agent.

[0017] As a preferred technical solution, the pH-responsive polymer is at least one of polymethacrylic acid, polyacrylic acid, and methacrylic acid-ethyl acrylate copolymer (1:1).

[0018] The present invention also provides a composite anti-corrosion coating for a steel grating plate, and the anti-corrosion coating is prepared using the above-mentioned method for preparing the composite anti-corrosion coating for a steel grating plate.

[0019] Beneficial effects of the present invention: The present invention's method for preparing a composite anti-corrosion coating for steel gratings utilizes innovative methods: filling the hollow fibers with a corrosion inhibitor and performing an end-capping treatment, as well as coating the fiber surfaces with a pH-responsive polymer. This method not only achieves the coating's self-repairing function but also enables intelligent response in acidic environments. This design not only enhances the coating's corrosion resistance but also maintains its mechanical properties and stability, helping to extend the service life of the steel gratings and reduce maintenance costs.

[0020] In general, the composite anti-corrosion coating for steel gratings of the present invention not only has excellent anti-corrosion performance and self-repairing ability, but also improves the durability and adaptability of the coating through an intelligent response mechanism, which can meet the long-term stable use requirements in highly corrosive environments such as oceans and chemical industries. DETAILED DESCRIPTION

[0021] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations. Example 1

[0022] The method for preparing the composite anti-corrosion coating of the steel grating plate of this embodiment comprises the following steps: S1: A self-healing polymer solution was used for spinning to form hollow fibers with a hollow structure. The self-healing polymer solution was prepared from the following raw materials in parts by weight: 10 parts disulfide-modified polyurethane, 20 parts epoxy resin, 5 parts nano-zinc oxide, 2 parts corrosion inhibitor (benzotriazole), 2.5 parts antibacterial agent (silver ion antibacterial agent), 1.5 parts plasticizer (dibutyl phthalate), and 1 part stabilizer (polyvinyl alcohol). The disulfide-modified polyurethane was obtained by reacting a polyurethane prepolymer containing at least two isocyanate end groups with N,N'-bis(2-hydroxyethyl)dithioacetamide. Specifically, the polyurethane prepolymer and N,N'-bis(2-hydroxyethyl)dithioacetamide were mixed in a molar ratio of 1:1.2 and reacted at 80°C for 4 hours to obtain the disulfide-modified polyurethane. The spinning parameters were set as follows: spinning voltage 15 kV, spinning distance 20 cm, and flow rate 1.2 mL / h. The above spinning operation can form a hollow fiber with a length of 10 mm and a pore diameter of 6 μm.

[0023] S2: Soak the hollow fiber obtained in step S1 in a corrosion inhibitor solution containing ethanol, ensuring that the solution fully fills the hollow fiber. The corrosion inhibitor solution contains an amine curing agent (phenalkamine curing agent), a corrosion inhibitor (benzotriazole), and an organic antibacterial agent (comprising isothiazolinone and polyhexamethyleneguanidine in a mass ratio of 2:3) in a 5:3:1 ratio. After soaking, a chemical end-capping agent (epoxy resin end-capping agent) is used to seal both ends of the hollow fiber to ensure the stability of the corrosion inhibitor solution within the fiber and prevent premature loss during subsequent processing.

[0024] S3: The hollow fibers filled and capped in step S2 were heat treated in a nitrogen atmosphere furnace at 70°C for 3 hours. During the heat treatment, ethanol evaporated from the fiber surface, while the amine curing agent (phenalkamine curing agent), corrosion inhibitor (benzotriazole), and organic antimicrobial agent (composed of isothiazolinone and polyhexamethyleneguanidine) adhered to the inner surface of the hollow fibers, forming a porous hollow fiber structure.

[0025] S4: The surface of the heat-treated hollow fiber from step S3 is uniformly coated with a pH-responsive polymer. The coating method comprises immersing the hollow fiber in a 15 wt% solution of the pH-responsive polymer (polymethacrylic acid) and tetrahydrofuran (THF) for 60 minutes, followed by drying at 70°C.

[0026] S5: The hollow fibers coated in step S4 are mixed with an anti-corrosion coating in a mass ratio of 1:20. The anti-corrosion coating is prepared by mixing component A and component B in a weight ratio of 5:2, wherein component A is composed of the following raw materials in parts by weight: 25 parts epoxy resin, 15 parts nano-titanium dioxide powder, 5 parts graphene oxide, 5 parts montmorillonite, 7 parts lignin sulfonate, 0.4 parts water-soluble silicone oil, 0.8 parts polyurethane, and 0.2 parts organic bentonite; and component B is composed of ketimine and aluminum chloride in a weight ratio of 5:1. The mixed coating is sprayed onto the surface of the steel grating. After spraying, the steel grating is placed in a curing device at a controlled temperature of 120°C for 6 hours to completely cure the coating, thereby obtaining the composite anti-corrosion coating for the steel grating. Example 2

[0027] The method for preparing the composite anti-corrosion coating of the steel grating plate of this embodiment comprises the following steps: S1: Spinning a self-healing polymer solution to form a hollow fiber with a hollow structure. The self-healing polymer solution is prepared from the following raw materials in parts by weight: 20 parts disulfide-modified polyurethane, 30 parts epoxy resin, 10 parts nano-zinc oxide, 6 parts corrosion inhibitor (benzotriazole), 5.5 parts antibacterial agent (silver ion antibacterial agent), 2.5 parts plasticizer (dibutyl phthalate), and 3 parts stabilizer (polyvinyl alcohol). The disulfide-modified polyurethane is the same as in Example 1. The spinning parameters are the same as in Example 1. This spinning operation can form a hollow fiber with a length of 10 mm and a pore diameter of 6 μm.

[0028] S2: Soak the hollow fiber obtained in step S1 in a corrosion inhibitor solution containing ethanol as the solvent, ensuring that the corrosion inhibitor fully fills the interior of the hollow fiber. The corrosion inhibitor solution contains an amine curing agent (alicyclic amine curing agent), a corrosion inhibitor (methylbenzotriazole), and an organic antibacterial agent (same as in Example 1) in a mass ratio of 5:3:2. After soaking, a chemical end-capping agent (epoxy resin end-capping agent) is used to seal both ends of the hollow fiber to ensure the stability of the corrosion inhibitor solution within the fiber and prevent premature loss during subsequent processing.

[0029] S3: The hollow fibers filled and capped in step S2 are heat treated in a nitrogen atmosphere furnace at 70°C for 3 hours. During the heat treatment, the ethanol evaporates from the fiber surface, while the amine curing agent (alicyclic amine curing agent), corrosion inhibitor (methylbenzotriazole), and organic antimicrobial agent adhere to the inner surface of the hollow fibers, forming a porous hollow fiber structure.

[0030] S4: The surface of the hollow fiber heat-treated in step S3 is uniformly coated with a pH-responsive polymer. The coating method comprises immersing the hollow fiber in a 15 wt% solution of the pH-responsive polymer (polyacrylic acid) and tetrahydrofuran (THF) for 60 minutes, followed by drying at 70°C.

[0031] S5: The hollow fibers coated in step S4 are mixed with an anti-corrosion coating in a mass ratio of 1:15, wherein the anti-corrosion coating is the same as that in Example 1. The mixed coating is sprayed on the surface of the steel grating. After spraying, the steel grating is placed in a curing device, the temperature is controlled at 120° C., and the curing time is 6 hours to completely cure the coating, thereby obtaining the composite anti-corrosion coating for the steel grating. Example 3

[0032] The method for preparing the composite anti-corrosion coating of the steel grating plate of this embodiment comprises the following steps: S1: Spinning a self-healing polymer solution to form a hollow fiber with a hollow structure. The self-healing polymer solution is prepared from the following raw materials in parts by weight: 30 parts disulfide-modified polyurethane, 40 parts epoxy resin, 15 parts nano-zinc oxide, 10 parts corrosion inhibitor (benzotriazole), 8 parts antibacterial agent (silver ion antibacterial agent), 3.5 parts plasticizer (dibutyl phthalate), and 5 parts stabilizer (polyvinyl alcohol). The disulfide-modified polyurethane is the same as in Example 1. The spinning parameters are the same as in Example 1. This spinning operation can form a hollow fiber with a length of 10 mm and a pore diameter of 6 μm.

[0033] S2: Soak the hollow fiber obtained in step S1 in a corrosion inhibitor solution containing ethanol, ensuring that the solution fully fills the hollow fiber. The corrosion inhibitor solution contains an amine curing agent (fatty amine curing agent), a corrosion inhibitor (2-mercaptobenzothiazole), and an organic antimicrobial agent (same as in Example 1) in a mass ratio of 7:2:3. After soaking, a chemical end-capping agent (epoxy resin end-capping agent) is used to seal both ends of the hollow fiber to ensure the stability of the corrosion inhibitor solution within the fiber and prevent premature loss during subsequent processing.

[0034] S3: The hollow fibers filled and capped in step S2 are heat treated in a nitrogen atmosphere furnace at 70°C for 3 hours. During the heat treatment, ethanol evaporates from the fiber surface, while the amine curing agent (fatty amine curing agent), corrosion inhibitor (2-mercaptobenzothiazole), and organic antimicrobial agent adhere to the inner surface of the hollow fibers, forming a porous hollow fiber structure.

[0035] S4: The surface of the heat-treated hollow fiber from step S3 is uniformly coated with a pH-responsive polymer. The coating method comprises immersing the hollow fiber in a 15 wt% solution of a pH-responsive polymer (methacrylic acid-ethyl acrylate copolymer (1:1)) and tetrahydrofuran (THF) for 60 minutes, followed by drying at 70°C.

[0036] S5: The hollow fibers coated in step S4 are mixed with an anti-corrosion coating in a mass ratio of 3:40, wherein the anti-corrosion coating is the same as that in Example 1. The mixed coating is sprayed on the surface of the steel grating. After spraying, the steel grating is placed in a curing device, the temperature is controlled at 120° C., and the curing time is 6 hours to completely cure the coating, thereby obtaining the composite anti-corrosion coating for the steel grating.

[0037] Comparative Example 1 The raw material composition and preparation steps of the composite anti-corrosion coating for steel gratings in this comparative example are basically the same as those in Example 1, except that, in the preparation method of this comparative example, conventional polyurethane is used instead of disulfide bond-modified polyurethane in step S1.

[0038] Comparative Example 2 The raw material composition and preparation steps of the composite anti-corrosion coating for steel gratings in this comparative example are basically the same as those in Example 1, except that steps S2 to S4 are not performed in the preparation method of this comparative example.

[0039] The performance of the steel grating composite anti-corrosion coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 2 was tested, and the performance results are shown in Table 1: Among them, salt spray resistance test: According to GB / T 1771 "Determination of resistance to neutral salt spray of paints and varnishes", the prepared steel grating composite anti-corrosion coating sample was cut into 150mm×70mm test pieces, and the surface of the test piece was gently polished with sandpaper to remove impurities, and then wiped clean with anhydrous ethanol. The test piece was placed in a salt spray test chamber, ensuring that the surface of the test piece was facing upward and at an angle of 15° to 30° to the vertical direction. The test chamber temperature was set to 35°C, and the salt solution concentration was 5% (mass fraction) NaCl solution, and the salt spray test was carried out.

[0040] Scratch Repair Rate Test: Using a custom test method, the prepared steel grating composite anti-corrosion coating sample was cut into a 100mm x 100mm test piece. A scratching tool was used to inscribe a scratch approximately 0.5mm deep on the surface of the test piece, ensuring that the scratch penetrated the coating without damaging the substrate. The scratched test piece was placed in an acidic environment (pH 4) at a temperature of 25°C ± 2°C. After 24 hours, the test piece was removed and the repair of the scratch was observed under a microscope. The area of the repaired area was recorded and the scratch repair rate was calculated using the formula: Repair Rate (%) = (Area of Repaired Area / Total Scratched Area) × 100%.

[0041] Abrasion Resistance Test: According to GB / T 1768, "Determination of Abrasion Resistance of Paint Films," the prepared steel grating composite anti-corrosion coating samples were cut into 100 mm x 100 mm test pieces. The surface of the test piece was lightly sanded with sandpaper to remove impurities and then wiped clean with anhydrous ethanol. The test piece was mounted on an abrasion tester, ensuring the surface was flat. The abrasion tester was set to 1000 rpm and a speed of 60 rpm. The abrasion test was then started. After the test, the coating wear was observed under a microscope, and the wear depth was recorded to evaluate the coating's wear resistance.

[0042] Impact resistance test: According to GB / T 1732, "Determination of impact resistance of paint films," cut the prepared steel grating composite anti-corrosion coating sample into a 50mm x 50mm test piece. Lightly sand the surface of the test piece with sandpaper to remove impurities, then wipe it clean with anhydrous ethanol. Place the test piece in the impact tester, ensuring the surface is flat, and start the impact tester to perform the impact test on the test piece.

[0043] Table 1

[0044] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. Various changes and improvements are possible without departing from the spirit and scope of the present invention, and such changes and improvements fall within the scope of the invention as claimed.

Claims

1. A method for preparing a composite anti-corrosion coating for a steel grating, characterized in that: The preparation method comprises the following steps: S1: Spinning operation is performed using a self-repairing polymer solution to form a hollow fiber with a hollow structure; S2: Soaking the hollow fiber obtained in step S1 in a corrosion inhibitor containing ethanol as a solvent, so that the corrosion inhibitor fills the interior of the hollow fiber, and then performing an end-capping treatment on the hollow fiber; S3: heat-treating the hollow fiber filled and capped in step S2 to volatilize ethanol from the fiber surface, thereby forming a hollow fiber with a porous structure; S4: coating the surface of the hollow fiber heat-treated in step S3 with a layer of pH-responsive polymer; S5: mixing the hollow fibers coated in step S4 with an anti-corrosion coating, spraying the mixture on the surface of the steel grating, and performing a curing treatment to prepare the composite anti-corrosion coating.

2. The method for preparing the composite anti-corrosion coating of the steel grating according to claim 1, characterized in that: The self-repairing polymer solution comprises the following raw materials in parts by weight: 10 to 30 parts of disulfide bond modified polyurethane, 20 to 40 parts of epoxy resin, 5 to 15 parts of nano zinc oxide, 1 to 10 parts of corrosion inhibitor, 1 to 10 parts of antibacterial agent, 1 to 5 parts of plasticizer and 1 to 5 parts of stabilizer.

3. The method for preparing the composite anti-corrosion coating of the steel grating according to claim 2, characterized in that: The disulfide bond modified polyurethane is obtained by reacting a polyurethane prepolymer containing at least two isocyanate terminal groups with N,N'-bis(2-hydroxyethyl)dithioacetamide.

4. The method for preparing a composite anti-corrosion coating for a steel grating according to claim 1, wherein: The corrosion inhibition liquid further comprises an amine curing agent, a corrosion inhibitor and an organic antibacterial agent.

5. The method for preparing the composite anti-corrosion coating of the steel grating according to claim 4, characterized in that: The amine curing agent is at least one of a phenolic amine curing agent, an alicyclic amine curing agent and a fatty amine curing agent.

6. The method for preparing a composite anti-corrosion coating for a steel grating as claimed in claim 4, characterized in that: The corrosion inhibitor is at least one of benzotriazole, methylbenzotriazole and 2-mercaptobenzothiazole.

7. The method for preparing a composite anti-corrosion coating for a steel grating as claimed in claim 4, characterized in that: The organic antibacterial agent consists of isothiazolinone and polyhexamethyleneguanidine.

8. The method for preparing a composite anti-corrosion coating for a steel grating as claimed in claim 1, characterized in that: The end-capping treatment is to use a chemical end-capping agent to block the two ends of the hollow fiber. The chemical end-capping agent is a silane coupling agent and / or an epoxy resin end-capping agent.

9. The method for preparing a composite anti-corrosion coating for a steel grating as claimed in claim 1, characterized in that: The pH-responsive polymer is at least one of polymethacrylic acid, polyacrylic acid, and methacrylic acid-ethyl acrylate copolymer (1:1).

10. A composite anti-corrosion coating for steel grating, characterized in that: The anti-corrosion coating is prepared by the preparation method of the composite anti-corrosion coating for steel grating according to any one of claims 1 to 9.

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