A composite anti-corrosion coating for concrete suitable for marine environments and its preparation method

Abstract

This invention belongs to the field of concrete material corrosion protection technology, and discloses a composite anti-corrosion coating suitable for concrete in marine environments and its preparation method. The composite anti-corrosion coating comprises a primer and a topcoat. The primer is made of polyethylene glycol-modified epoxy resin. By weight, the topcoat comprises: 1-5 parts of nano-zirconia powder, 0.5-2.5 parts of fluorinated organosilicon compound, 100 parts of polyurethane prepolymer, and 20 parts of polyurethane curing agent. The coating of this invention has relatively low cost, does not cause secondary pollution, and has good durability and safety.

Description

Technical Field

[0001] This invention belongs to the field of concrete material corrosion protection technology, specifically relating to a composite anti-corrosion coating suitable for concrete in marine environments and its preparation method. Background Technology

[0002] The marine environment, with its extreme natural conditions and complex ecosystem characteristics, poses severe challenges and tests to concrete structures. In critical infrastructure applications such as bridges, docks, and offshore wind turbines, concrete materials must withstand long-term natural weathering, as well as severe corrosion from salt spray, the erosive effects of deep seawater immersion, the physical abrasion from continuous wave impact, and the complex biochemical erosion caused by marine biological activity. The combined effect of these multiple environmental factors gradually leads to the erosion of the mortar layer on the concrete surface and accelerated corrosion of the internal steel reinforcement, resulting in significant degradation of structural performance. In extreme cases, this degradation will severely weaken the overall stability of infrastructure, shorten its expected service life, and thus pose a significant potential threat to public safety. Therefore, developing effective protective technologies and materials for concrete structures in marine environments to address these challenges is particularly important.

[0003] Although various concrete protective coatings designed to combat marine environmental erosion exist on the market, these solutions still face a series of significant challenges in practical applications. Especially under long-term exposure to the marine environment, most coatings inevitably experience cracking and peeling. This phenomenon stems from the complex interplay of multiple factors. First, the salt and other chemical components in seawater are highly corrosive, capable of penetrating the coating and reacting chemically with the coating material, leading to a gradual decline in coating performance and eventually crack formation. These chemical reactions not only weaken the structural integrity of the coating but also reduce its resistance to external erosion. Second, the adhesion between the coating and the concrete surface is a key factor affecting coating durability. Insufficient adhesion allows the coating to easily peel off from the concrete surface under the influence of external environmental factors such as wave impact and salt spray corrosion. This peeling not only damages the integrity of the coating but also accelerates the corrosion process of the concrete structure. Furthermore, salt and other dissolved substances in seawater can penetrate through the micropores or cracks in the coating to the space between the coating and the substrate, forming a water film. The presence of this water film further weakens the adhesion between the coating and the substrate, exacerbating the tendency for the coating to peel off. Once the coating peels off, corrosive substances in the seawater will act more directly on the concrete structure, leading to more severe corrosion damage.

[0004] Therefore, there is an urgent need to develop a composite coating that is durable, easy to construct, and cost-effective to improve the durability of marine concrete structures, reduce long-term maintenance costs, and thus provide a safe and reliable protective barrier for marine engineering. Enhancing the durability of concrete structures can significantly extend the service life of infrastructure, effectively reduce maintenance and replacement costs caused by corrosion, and also play a positive role in the protection and maintenance of the ecological environment.

[0005] Chinese invention patent application CN117165176A discloses a concrete coating and its preparation method, relating to the field of concrete surface protective coating technology. It includes a main agent and a curing agent, with a weight ratio of 7-11:1. The main agent comprises a heat-stable resin prepolymer, pigments, fillers, solvents, and other additives. This invention optimizes the material formulation and epoxy resin modification process, controlling the ratio of epoxy groups and hydroxyl groups to reduce the particle size in the epoxy emulsion, thereby improving its overall stability. This largely avoids the increased particle energy and higher collision probability caused by tropical high temperatures, which could lead to aggregation and fusion, resulting in decreased stability of the concrete coating. It also improves the stability of the concrete coating during high-temperature storage, allowing it to be stored for a long time without deterioration in tropical marine environments. Simultaneously, after application, a protective coating is formed on the concrete surface, providing good protection for the concrete structure. However, solvent-based coatings contain volatile organic compounds (VOCs), which not only pollute the environment but may also have adverse effects on human health.

[0006] Chinese invention patent application CN112778874A discloses a corrosion-resistant coating for marine engineering concrete and its preparation method. The corrosion-resistant coating is applied to the concrete surface by spraying or brushing after uniformly mixing component A and component B. Component A, by weight, includes: water-based nonionic epoxy resin, C10-C12 alkyl glycidyl ether, cage-type silsesquioxane, metal powder, magnesium aluminum hydrotalcite powder, dispersant, and defoamer. Component B, by weight, includes: modified aromatic amine curing agent, C10-C12 alkyl glycidyl ether, self-healing microcapsules, leveling agent, antioxidant, adhesion promoter, and other additives. The corrosion-resistant coating of this invention exhibits excellent adhesion and corrosion resistance, while also achieving self-healing and preventing chloride ion migration, thereby extending the service life of the concrete structure. It can be widely used for the protection of marine engineering concrete structures. However, the modified aromatic amine curing agent may have some toxicity, requiring appropriate protective measures.

[0007] Chinese invention patent application CN114315417A discloses a multifunctional anti-chlorine and antifouling coating for marine concrete based on oil-injected polydimethylsiloxane (PDMS). The method involves first coating a PDMS layer onto the concrete surface, then injecting dimethyl silicone oil into the PDMS coating on the concrete surface and into the micropores within the concrete at a certain depth, forming a dense, hydrophobic, and biomimetic super-slippery coating. The invention also provides a method for preparing the coating. However, PDMS exhibits certain elastic-plastic properties, which may make its stability at the microstructural level less than that of other rigid materials. In a marine environment, under dynamic loads such as waves and tides, the mechanical properties of the coating may decrease, thus affecting its anti-chlorine and antifouling functions. Summary of the Invention

[0008] To address the problems existing in the prior art, the present invention aims to provide a composite anti-corrosion coating for concrete suitable for marine environments and its preparation method. The coating of the present invention has relatively low cost, does not cause secondary pollution, and has good durability and safety.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A composite anti-corrosion coating suitable for concrete in marine environments, the raw materials of which include a coating primer and a coating topcoat;

[0011] The coating primer is made of polyethylene glycol modified epoxy resin;

[0012] The coating topcoat comprises, by weight, 1-5 parts of nano-zirconia powder, 0.5-2.5 parts of fluorinated organosilicon compound, 100 parts of polyurethane prepolymer, and 20 parts of polyurethane curing agent.

[0013] Preferably, the polyethylene glycol modified epoxy resin is prepared by mixing 100 parts epoxy resin and 3 parts polyethylene glycol by weight.

[0014] Preferably, the epoxy resin is 6101 epoxy resin with a medium epoxy value.

[0015] Preferably, the polyethylene glycol used is PEG200.

[0016] Preferably, the nano-zirconia powder is high-purity nano-zirconia with an average particle size of 20 nm and a content of ≥99.9%.

[0017] Preferably, the fluorinated organosilicon compound is one of perfluorooctyltriethylsilane, perfluorodecyltrimethoxysilane, and fluoropropylmethyldimethoxysilane.

[0018] Preferably, the fluorinated organosilicon compound has an analytical purity of ≥98%.

[0019] Preferably, the polyurethane prepolymer is one of PTMG type polyurethane prepolymer and polyurethane diol prepolymer.

[0020] This invention also provides a method for preparing a composite anti-corrosion coating for concrete suitable for marine environments, as described above, comprising:

[0021] Apply a primer to a clean, dry concrete surface to form a stable base layer;

[0022] A topcoat is applied to the bottom surface, and after curing, a complete protective shell is formed.

[0023] Preferably, the preparation process of the coating topcoat includes:

[0024] Nano-zirconia powder is added to polyurethane prepolymer and stirred to uniformly disperse the nano-zirconia powder, thus obtaining the first mixture.

[0025] A fluorinated organosilicon compound is added to the first mixture and stirred to ensure uniform distribution of the fluorinated organosilicon compound, thereby obtaining a second mixture.

[0026] Add the curing agent to the second mixture, stir evenly and avoid the generation of bubbles to obtain the coating topcoat.

[0027] The present invention has the following beneficial effects:

[0028] This invention relates to a composite anti-corrosion coating for concrete in marine environments, comprising a primer and a topcoat. The inner layer (primer) is designed as follows: Modified epoxy resin: As the inner layer material, polyethylene glycol (PEG) is used to modify the epoxy resin, improving its toughness and enabling it to penetrate deeply into the microporous structure of the concrete. Its active groups (such as hydroxyl and carboxyl groups) react chemically with silicate minerals or other active components on the concrete surface, forming stable chemical bonds and providing excellent adhesion and moisture resistance. The modified epoxy resin in the inner layer can penetrate into the concrete, filling microcracks and pores to form a dense waterproof barrier, preventing the penetration of salt and moisture, and effectively inhibiting alkali-aggregate reactions and steel corrosion within the concrete. The topcoat is designed as follows: Polyurethane is selected as the base material for the coating. This material not only effectively resists physical impacts and deformations in the marine environment but also recovers its original shape after being subjected to external forces, ensuring the integrity of the coating remains intact. Secondly, nano-zirconia particles were selected as the reinforcing filler, possessing extremely high hardness and wear resistance. When nano-zirconia is uniformly dispersed in the coating system, its tiny size allows it to deeply fill the micropores within the coating, increasing its density and effectively preventing the penetration of seawater and other corrosive media. Considering the humid and hot conditions present in marine environments, a fluorinated organosilicon compound was also introduced onto the coating surface. This compound, due to the presence of fluorine in its molecular chain, exhibits hydrophobicity. It can significantly reduce the surface energy of the coating surface, causing water droplets to form spherical shapes on its surface, reducing the contact area between water molecules and the coating, thereby greatly improving the waterproof performance of the coating and resulting in good durability and safety of the coating of this invention. Furthermore, the raw materials for the coating of this invention are simple and readily available, with relatively low cost, and do not cause secondary pollution. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the composite anti-corrosion coating for concrete suitable for marine environments in an embodiment of the present invention;

[0030] In the diagram, 1 represents the base layer, 2 represents the bottom layer, and 3 represents the top layer. Detailed Implementation

[0031] The technical solution of the present invention is described below with reference to specific embodiments. Each embodiment is an experimental example and provides real performance test data. 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.

[0032] This invention proposes an innovative composite coating technology specifically designed for concrete structures in marine environments. It aims to overcome the shortcomings of existing technologies and provide a comprehensive protective solution. The composite coating comprises an inner layer (or base layer) and a top layer. The inner layer uses polyethylene glycol (PEG) modified epoxy resin, while the top layer uses a polyurethane coating doped with nano-sized zirconium oxide and fluorinated organosilicon compounds. The modified epoxy resin in the inner layer can deeply penetrate the micropores of the concrete, forming chemical bonds with the concrete and improving adhesion. The nano-sized zirconium oxide and fluorinated organosilicon compounds in the top layer work together to significantly improve the durability of the concrete substrate.

[0033] The present invention relates to a composite anti-corrosion coating for concrete in marine environments, comprising the following raw materials in parts by weight: 100 parts epoxy resin, 3 parts polyethylene glycol, 1-5 parts nano-zirconia powder, 0.5-2.5 parts fluorinated organosilicon compound, 100 parts polyurethane prepolymer, and 20 parts polyurethane curing agent.

[0034] The epoxy resin used is 6101 epoxy resin with a medium epoxy value. The polyethylene glycol used is PEG200 with a low molecular weight. The fluorinated organosilicon compound has an analytical purity of ≥98%, and is selected from one of perfluorooctyltriethylsilane, perfluorodecyltrimethoxysilane, and trifluoropropylmethyldimethoxysilane. The nano-zirconia powder is high-purity nano-zirconia with an average particle size of 20 nm and a content of ≥99.9%. The polyurethane prepolymer is one of PTMG-type polyurethane prepolymer and polyurethane glycol prepolymer.

[0035] The present invention provides a method for preparing a composite anti-corrosion coating for concrete suitable for marine environments, comprising the following steps:

[0036] 1) Inner layer preparation: First, polyethylene glycol and epoxy resin are uniformly mixed to obtain polyethylene glycol modified epoxy resin. In this invention, the epoxy resin is modified to enhance the adhesion and chemical corrosion resistance between the epoxy resin and the concrete structure. The polyethylene glycol modified epoxy resin is then coated on a clean and dry concrete surface. The excellent permeability and adhesion of the polyethylene glycol modified epoxy resin are utilized to form a stable bottom layer.

[0037] 2) Topcoat Preparation: Nano-zirconia powder is slowly added to the polyurethane prepolymer. A high-speed disperser or ultrasonic processor is used to evenly disperse the nano-zirconia powder, preventing agglomeration. Then, a fluorinated organosilicon compound is added and thoroughly stirred again to ensure uniform distribution. Next, the appropriate polyurethane curing agent is added to the mixture, and it is stirred quickly and evenly to avoid bubble formation, resulting in a topcoat. This topcoat is then applied to the underlayer. The formed polyurethane acts as a binder, firmly binding the nano-zirconia particles and the fluorinated organosilicon compound together to form a continuous and dense protective layer. The nano-zirconia particles exist in a uniformly dispersed manner in the topcoat, forming a micro-barrier layer that effectively prevents the penetration of harmful substances such as moisture and salt. The fluorinated organosilicon compound forms a low surface energy protective film on the surface of the topcoat, improving the hydrophobicity and anti-fouling properties of the coating. Applying the topcoat of this invention over the inner layer provides additional wear resistance, corrosion resistance, and weather resistance.

[0038] 3) Curing and Post-treatment: Based on environmental conditions, appropriately control the curing time and temperature to ensure the coating fully cures and forms a complete protective shell. After curing, perform necessary surface inspections and repairs to ensure the integrity and effectiveness of the coating.

[0039] Through the above design, the composite coating of the present invention can achieve multi-layer protection for concrete structures, effectively resisting the erosion of the marine environment, significantly improving the durability and safety of concrete structures, reducing long-term maintenance costs, and providing reliable protection for marine infrastructure.

[0040] Example 1:

[0041] The composite anti-corrosion coating for concrete in this embodiment, applicable to marine environments, is prepared according to the following components by weight: 100 parts epoxy resin, 3 parts polyethylene glycol, 1 part zirconium oxide, 0.5 parts perfluorodecyltrimethoxysilane, 100 parts PTMG type polyurethane prepolymer, and 20 parts polyurethane curing agent.

[0042] This embodiment describes a method for preparing a composite anti-corrosion coating for concrete in a marine environment, including the following steps:

[0043] 1) Add 3 parts of polyethylene glycol to 100 parts of epoxy resin and stir for 1 minute until uniform to obtain a composite coating primer.

[0044] 2) Mix 100 parts of PTMG type polyurethane prepolymer with 20 parts of curing agent evenly; slowly add 1 part of nano-zirconia powder to the above mixture, and use a high-speed disperser to evenly disperse the nano-zirconia powder; then add 0.5 parts of perfluorodecyltrimethoxysilane to the mixture containing nano-zirconia, and stir thoroughly again to obtain the composite coating primer.

[0045] When using this product, first apply a composite coating primer to the concrete surface; then apply a composite coating topcoat over the primer. After curing, the primer and topcoat layers together form an anti-corrosion concrete composite coating. The thickness of the primer layer is controlled at 50-70 μm, and the thickness of the topcoat layer is controlled at 80-120 μm.

[0046] Example 2:

[0047] The composite anti-corrosion coating for concrete in this embodiment, applicable to marine environments, is prepared according to the following components by weight: 100 parts epoxy resin, 3 parts polyethylene glycol, 3 parts zirconium oxide, 0.5 parts perfluorodecyltrimethoxysilane, 100 parts PTMG type polyurethane prepolymer, and 20 parts polyurethane curing agent.

[0048] The preparation process of the composite anti-corrosion coating for concrete in this embodiment is the same as that in the previous embodiment.

[0049] Example 3:

[0050] The composite anti-corrosion coating for concrete in this embodiment, applicable to marine environments, is prepared according to the following components by weight: 100 parts epoxy resin, 3 parts polyethylene glycol, 5 parts zirconium oxide, 0.5 parts perfluorodecyltrimethoxysilane, 100 parts PTMG type polyurethane prepolymer, and 20 parts polyurethane curing agent.

[0051] The preparation process of the composite anti-corrosion coating for concrete in this embodiment is the same as that in the previous embodiment.

[0052] Example 4:

[0053] The composite anti-corrosion coating for concrete in this embodiment, applicable to marine environments, is prepared according to the following components by weight: 100 parts epoxy resin, 3 parts polyethylene glycol, 1 part zirconium oxide, 1.5 parts perfluorodecyltrimethoxysilane, 100 parts PTMG type polyurethane prepolymer, and 20 parts polyurethane curing agent.

[0054] The preparation process of the composite anti-corrosion coating for concrete in this embodiment is the same as that in the previous embodiment.

[0055] Example 5:

[0056] The composite anti-corrosion coating for concrete in this embodiment, applicable to marine environments, is prepared according to the following components by weight: 100 parts epoxy resin, 3 parts polyethylene glycol, 3 parts zirconium oxide, 1.5 parts perfluorodecyltrimethoxysilane, 100 parts PTMG type polyurethane prepolymer, and 20 parts polyurethane curing agent.

[0057] The preparation process of the composite anti-corrosion coating for concrete in this embodiment is the same as that in the previous embodiment.

[0058] Example 6:

[0059] The composite anti-corrosion coating for concrete in this embodiment, applicable to marine environments, is prepared according to the following components by weight: 100 parts epoxy resin, 3 parts polyethylene glycol, 5 parts zirconium oxide, 1.5 parts perfluorodecyltrimethoxysilane, 100 parts PTMG type polyurethane prepolymer, and 20 parts polyurethane curing agent.

[0060] The preparation process of the composite anti-corrosion coating for concrete in this embodiment is the same as that in the previous embodiment.

[0061] Example 7:

[0062] The composite anti-corrosion coating for concrete in this embodiment, applicable to marine environments, is prepared according to the following components by weight: 100 parts epoxy resin, 3 parts polyethylene glycol, 1 part zirconium oxide, 2.5 parts perfluorodecyltrimethoxysilane, 100 parts PTMG type polyurethane prepolymer, and 20 parts polyurethane curing agent.

[0063] The preparation process of the composite anti-corrosion coating for concrete in this embodiment is the same as that in the previous embodiment.

[0064] Example 8:

[0065] The composite anti-corrosion coating for concrete in this embodiment, applicable to marine environments, is prepared according to the following components by weight: 100 parts epoxy resin, 3 parts polyethylene glycol, 3 parts zirconium oxide, 2.5 parts perfluorodecyltrimethoxysilane, 100 parts PTMG type polyurethane prepolymer, and 20 parts polyurethane curing agent.

[0066] The preparation process of the composite anti-corrosion coating for concrete in this embodiment is the same as that in the previous embodiment.

[0067] Example 9:

[0068] The composite anti-corrosion coating for concrete in this embodiment, applicable to marine environments, is prepared according to the following components by weight: 100 parts epoxy resin, 3 parts polyethylene glycol, 5 parts zirconium oxide, 2.5 parts perfluorodecyltrimethoxysilane, 100 parts PTMG type polyurethane prepolymer, and 20 parts polyurethane curing agent.

[0069] The preparation process of the composite anti-corrosion coating for concrete in this embodiment is the same as that in the previous embodiment.

[0070] This invention employs a pull-out test method to determine the bond strength between the coating obtained in the above embodiments and the concrete substrate. The specific steps are as follows:

[0071] 1) Sample preparation: Select representative concrete specimens, ensuring the specimen surface is flat and clean. Then, evenly apply the developed composite coating material to the specimen surface; the coating thickness should meet the requirements of the actual application.

[0072] 2) Test tray installation: After the coating has fully cured, use a special adhesive to firmly attach the metal test tray to the coating surface, ensuring that there are no air bubbles or gaps between the test tray and the coating.

[0073] 3) Loading and Measurement: Connect the test disc to the pull-out test equipment and gradually increase the tensile force at a constant rate until the coating separates from the concrete substrate. Record the maximum tensile force value at the point of separation.

[0074] 4) Data processing: Calculate the bond strength between the coating and the substrate based on the maximum tensile force and the area of ​​the test plate.

[0075] The bond strength of the concrete coatings prepared in Examples 1-9 was tested, and the specific results are shown in Table 1:

[0076] Table 1

[0077]

[0078] As shown in Table 1, the test results indicate that the bond strength between the top and bottom layers significantly improves with increasing nano-zirconia doping content. This is because nano-zirconia particles are more uniformly dispersed in the coating, forming more contact points and thus enhancing the interaction between the top and bottom layers. Nano-zirconia effectively fills the tiny voids in the coating, optimizes the coating's microstructure, and constructs a stable interface layer between the top and bottom layers, which helps to significantly improve bond strength.

[0079] The concrete coatings prepared in Examples 1-9 were applied to concrete for performance testing. A concrete specimen without any surface treatment and with the same curing method was used as blank sample 0. The compressive strength (MPa) data of different examples under the simulated seawater solution (a mixed solution of 5wt% sodium chloride, 5wt% sodium sulfate and 90wt% water) wet-dry cycle conditions are shown in Table 2.

[0080] Table 2

[0081]

[0082] As can be seen from the test results listed in Table 2, the addition of nano-zirconia significantly improves the coating performance. It ensures that the coating's seal is not compromised. As the first line of defense for concrete, the integrity and seal of the coating are crucial to preventing moisture and other harmful substances from penetrating into the concrete. Therefore, the addition of nano-zirconia indirectly protects the concrete from external environmental erosion, thereby maintaining its original compressive strength and other mechanical properties.

[0083] On the other hand, fluorinated organosilicon compounds, due to their excellent hydrophobicity, can significantly reduce the penetration of water and salt, effectively preventing problems such as steel corrosion inside concrete. This allows the coating to better prevent the effects of corrosive factors such as salt spray, seawater immersion, and wave impact in the marine environment, thereby indirectly maintaining the compressive strength of concrete. The mass change rate and compressive corrosion resistance coefficient of different embodiments after 150 cycles of dry and wet treatment in simulated seawater solution are shown in Table 3.

[0084] Table 3

[0085]

[0086] The data analysis results in Table 3 show that nano-zirconia can reduce wear on the concrete surface, thereby delaying the loss of concrete quality. Furthermore, nano-zirconia particles can form a tiny barrier layer in the coating, which can prevent harmful substances such as moisture and salt from seawater or other water sources from entering the concrete interior, thus reducing changes in concrete quality. This protective mechanism not only helps maintain the mechanical properties of concrete but also extends its service life.

[0087] In the above-described technical solution of this invention, the inner layer uses modified epoxy resin as a primer. This material can form a strong chemical bond with the surface of the concrete substrate, effectively filling the pores of the concrete and significantly enhancing the waterproof and moisture-proof capabilities of the substrate, providing reliable support for subsequent coating layers. Furthermore, the top layer of the coating incorporates polyurethane, nano-zirconia, and fluorinated organosilicon compounds. Polyurethane acts as a binder, ensuring tight bonding between the components of the top layer. The reuse of nano-zirconia may be to further optimize the wear resistance and hardness of the top layer. More importantly, the addition of fluorinated organosilicon compounds endows the coating surface with hydrophobicity and chemical stability.

[0088] Fluorinated organosilicon compounds, due to their hydrophobic properties, can significantly reduce the penetration of water and salt, effectively preventing problems such as steel reinforcement corrosion within concrete and indirectly reducing concrete quality loss. Fluorinated organosilicon compounds can also improve the chemical resistance of the coating, reducing the corrosive effects of harmful substances such as sulfates and chloride ions in seawater on concrete, thereby reducing concrete quality loss. Simultaneously, fluorinated organosilicon compounds can also improve the weather resistance of the coating, enabling it to better protect against the corrosive effects of salt spray, seawater immersion, and wave impact in the marine environment, indirectly reducing changes in concrete quality.

[0089] This composite approach not only significantly improves the overall performance of the coating system, but also makes it more adaptable to harsh conditions, especially marine environments.

[0090] By using these materials, not only can the protective function of the coating be enhanced, but the service life of the concrete structure can also be extended, which is especially important for concrete structures used in marine environments.

[0091] As can be seen from the above, the present invention has the following advantages:

[0092] 1) The modified epoxy resin of the inner layer, as an organic compound, is selected as the bottom layer material due to its excellent adhesion, moisture resistance and chemical resistance. It can adhere tightly to the substrate, form a stable interface, and provide a solid foundation for the outer layer.

[0093] 2) The combination of nano-zirconia and fluorinated organosilicon compounds in the surface layer improves the hardness and wear resistance of the coating, while the fluorinated organosilicon compounds enhance the weather resistance and durability of the coating.

[0094] 3) The composite anti-corrosion coating for concrete in marine environments proposed in this invention has the advantages of low cost, convenient construction and strong durability compared with the prior art. It can effectively extend the service life of infrastructure and improve the stability and safety of the structure.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A composite anti-corrosion coating for concrete suitable for marine environments, characterized in that, Its raw materials include coating primer and coating topcoat; The coating primer is made of polyethylene glycol modified epoxy resin; The coating topcoat comprises, by weight, 1-5 parts of nano-zirconia powder, 0.5-2.5 parts of fluorinated organosilicon compound, 100 parts of polyurethane prepolymer, and 20 parts of polyurethane curing agent.

2. The composite anti-corrosion coating for concrete suitable for marine environments according to claim 1, characterized in that, The polyethylene glycol-modified epoxy resin is prepared by mixing 100 parts epoxy resin and 3 parts polyethylene glycol by weight.

3. A composite anti-corrosion coating suitable for concrete in a marine environment according to claim 1 or 2, characterized in that, The epoxy resin is 6101 epoxy resin with a medium epoxy value.

4. A composite anti-corrosion coating suitable for concrete in a marine environment according to claim 1 or 2, characterized in that, The polyethylene glycol used is PEG200.

5. A composite anti-corrosion coating for concrete suitable for marine environments according to claim 1, characterized in that, The nano-zirconia powder is high-purity nano-zirconia with an average particle size of 20 nm and a content of ≥99.9%.

6. The composite anti-corrosion coating for concrete suitable for marine environments according to claim 1, characterized in that, The fluorinated organosilicon compound is one of perfluorooctyltriethylsilane, perfluorodecyltrimethoxysilane, and fluoropropylmethyldimethoxysilane.

7. A composite anti-corrosion coating for concrete suitable for marine environments according to claim 6, characterized in that, The fluorinated organosilicon compound has an analytical purity of ≥98%.

8. A composite anti-corrosion coating for concrete suitable for marine environments according to claim 1, characterized in that, The polyurethane prepolymer is one of PTMG type polyurethane prepolymer and polyurethane diol prepolymer.

9. The method for preparing a composite anti-corrosion coating for concrete suitable for marine environments according to any one of claims 1-8, characterized in that, include: Apply a primer to a clean, dry concrete surface to form a stable base layer; A topcoat is applied to the bottom surface, and after curing, a complete protective shell is formed.

10. The method for preparing a composite anti-corrosion coating for concrete in a marine environment according to claim 9, characterized in that, The preparation process of the coating topcoat includes: Nano-zirconia powder is added to polyurethane prepolymer and stirred to uniformly disperse the nano-zirconia powder, thus obtaining the first mixture. A fluorinated organosilicon compound is added to the first mixture and stirred to ensure uniform distribution of the fluorinated organosilicon compound, thereby obtaining a second mixture. Add the curing agent to the second mixture, stir evenly and avoid the generation of bubbles to obtain the coating topcoat.

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