A weather-resistant and anti-aging protective layer for offshore wind power facilities and its preparation method

Abstract

This invention relates to a weather-resistant and anti-aging protective layer for offshore wind power facilities and its preparation method, belonging to the field of anti-corrosion coating technology. The preparation method includes: preparing a latent reactive conductive primer slurry; applying the latent reactive conductive primer slurry to a substrate surface and allowing it to semi-cure, followed by electrophoretic penetration treatment to obtain an electrophoretic latent reactive conductive primer layer; subjecting the electrophoretic latent reactive conductive primer layer to thermal curing treatment to obtain a cured primer layer; and applying a topcoat to the cured primer layer and curing it to obtain a weather-resistant and anti-aging protective layer. This invention improves the interfacial bonding strength and wet adhesion of the coating system by constructing a chemically bonded interface instead of a traditional physical interface; and effectively fills coating defects through electrophoretic penetration, improving the long-term protective performance of the coating under damaged conditions.

Description

Technical Field

[0001] This invention belongs to the field of anti-corrosion coating technology, specifically relating to a weather-resistant and anti-aging protective layer for offshore wind power facilities and its preparation method. Background Technology

[0002] Offshore wind power facilities operate in harsh marine environments for extended periods. Their foundations, especially those in the splash zone, face continuous challenges from alternating wet and dry conditions, salt spray corrosion, and wave impact. To address this environment, current protection solutions generally employ a multi-coat heavy-duty anti-corrosion system consisting of an epoxy zinc-rich primer, an epoxy intermediate coat, and a high-performance topcoat.

[0003] Under actual construction and long-term service conditions, the limitations of this protective solution have become increasingly apparent. Traditional construction processes result in each coating forming an independent film, layered sequentially. During the curing and film formation of the primer, micron-sized pores inevitably form on its surface due to factors such as solvent evaporation. After the epoxy zinc-rich primer is fully cured, the epoxy intermediate coat is applied using conventional spraying methods. This process creates a physical interface between the primer and intermediate coat, maintained by physical adsorption and mechanical interlocking forces. In the splash zone, water molecules continuously penetrate the coating and accumulate at this physical interface, gradually disrupting the physical forces between the interfaces and leading to decreased interlayer adhesion. This is the root cause of problems such as blistering and peeling after long-term service. Simultaneously, the fluidity and wettability of the coating are insufficient to completely penetrate and fill these micropores in the cured primer. These unfilled defects become preferential channels for the penetration of corrosive media such as chloride ions, weakening the physical shielding capability of the entire protective system and preventing it from reaching the theoretical level of protection. When wind turbine foundations are subjected to mechanical impacts during installation or subsequent operation and maintenance, causing scratches on the coating and damaging the steel substrate, corrosion immediately occurs at the damaged site. Since the interfaces between the primer and the steel substrate, as well as between different coating layers, are weak points in physical bonding, corrosive media can spread along these interfaces from the scratches to both sides, forming undercut corrosion. This laterally expanding corrosion pattern causes intact coatings to gradually peel off from the substrate, leading to a small initial damage point eventually evolving into large-area coating failure, significantly shortening the effective protective life of the system. Chinese invention patent application CN105713480A discloses an epoxy zinc-rich primer and its manufacturing method. Although it provides a primer with a wide application window, fast curing, strong adhesion, and excellent salt spray resistance, if the traditional multi-layer application process is still used subsequently, the risk of interlayer failure in the long-term extreme environment remains fundamentally unchanged. Chinese invention patent application CN120502481A discloses a corrosion protection process for ship lock steel structures. By using graphene-modified zinc powder primer and modified graphene oxide polyurethane topcoat in combination with high-performance epoxy intermediate paint, the overall performance of traditional partitioned anti-corrosion coatings is significantly improved and a single coating system is used to cover different areas of the hydraulic structure. However, the essentially multi-layer physical interface superimposed structure formed by conventional spraying construction remains unchanged.

[0004] Therefore, it is necessary to develop a weather-resistant and anti-aging protective layer that overcomes the microscopic defects of the primer and the insufficient physical bonding between traditional coatings, so as to be suitable for the service environment of offshore wind power facilities. Summary of the Invention

[0005] Existing multi-layered protective systems for offshore wind power foundations rely primarily on physical bonding between the coatings. However, the resulting physical interfaces are susceptible to moisture erosion in the marine environment, which reduces the bonding strength between the coatings and affects the long-term stability of the protective system.

[0006] To address the shortcomings of existing technologies, this invention provides a weather-resistant and anti-aging protective layer for offshore wind power facilities and its preparation method. The technical solution adopted by this invention is as follows: In a first aspect, the present invention provides a method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities, comprising the following steps: S1. Preparation of latent reactive conductive primer slurry; the latent reactive conductive primer slurry is prepared by mixing component A and modified polyamide curing agent at a mass ratio of 100:(9.7-13.6); component A contains, by mass, 800-1000 parts of bisphenol A type epoxy resin, 400-600 parts of mixed solvent, 30-60 parts of anti-settling agent, 900-1200 parts of zinc powder, 40-80 parts of conductive carbon black, and 3-7 parts of leveling agent; S2. Apply a latent reactive conductive primer slurry to the substrate surface and allow it to semi-cure to obtain a semi-cured latent reactive conductive primer layer. Perform electrophoretic penetration treatment on the semi-cured latent reactive conductive primer layer to form an electrophoretic layer, thereby obtaining an electrophoretic latent reactive conductive primer layer. The electrolyte for the electrophoretic penetration treatment contains 30-80g of aqueous polyetheramine and 8-15g of tetrabutylammonium bromide per liter, with a pH value of 4.5-6.0. S3. Perform a heat curing treatment on the electrophoretic latent reactive conductive primer layer to obtain a cured primer layer; S4. Apply the topcoat over the cured primer layer and cure it to obtain a weather-resistant and anti-aging protective layer.

[0007] This invention, through the above-described technical solution, constructs a chemically bonded gradient interpenetrating network between the primer and subsequent functional layers, replacing the physical interface between traditional coatings. Its technical mechanism lies in: Formation of latent reactive interfaces: By controlling the stoichiometric ratio of bisphenol A type epoxy resin to modified polyamide curing agent, a semi-cured primer layer (semi-cured latent reactive conductive primer layer) was prepared. The addition ratio of component A to modified polyamide curing agent was such that the molar ratio of the total amount of active hydrogen to the total amount of epoxy groups in bisphenol A type epoxy resin in component A was 0.5:1 to 0.7:1. This ratio range ensures that the primer cures to form a solid paint film. While forming a preliminary cured network, a specific number of active epoxy groups are reserved in its structure. These epoxy groups provide active sites for subsequent chemical reactions.

[0008] Electrophoretic penetration of the reactive components: In an acidic electrolyte, the aqueous polyetheramine matrix is ​​protonated and becomes positively charged. Together with the tetrabutylammonium bromide cation, it migrates towards the coated steel plate, which serves as the cathode, under the influence of a DC electric field. The electric field force drives these ionic components to penetrate into the micropores and defects in the primer curing network, achieving effective filling of these areas.

[0009] In-situ interfacial polymerization and gradient network construction: In the subsequent heating and isothermal treatment steps, tetrabutylammonium bromide, which has already penetrated into the primer network, acts as a catalyst to promote the ring-opening addition reaction between the amino groups of the waterborne polyetheramine and the residual epoxy groups in the primer. This reaction forms covalent chemical bonds between the original primer network and the waterborne polyetheramine that has penetrated into the primer network, ultimately generating an interpenetrating polymer network structure with no obvious physical interface and a gradient distribution of components.

[0010] This technical solution transforms the physical bonding between coatings into chemical bonding, and the resulting integrated network structure enhances the density and interface stability of the protective layer, thereby improving its impermeability and adhesion in humid environments.

[0011] Preferably, the A component in step S1 comprises, by weight, 900 parts of bisphenol A type epoxy resin, 540 parts of mixed solvent, 45 parts of anti-settling agent, 1050 parts of zinc powder, 60 parts of conductive carbon black, and 5 parts of leveling agent.

[0012] Using this technical solution, the zinc powder in the formula provides cathodic protection for the coating, and the conductive carbon black imparts conductivity to the coating. Conductivity is a necessary condition for realizing the subsequent electrophoretic permeation step.

[0013] Furthermore, component A in step S1 comprises one or more of the following characteristics: The mixed solvent is a mixture of xylene and n-butanol in a mass ratio of (2.5-3.5):1; The anti-settling agent is organic bentonite; The leveling agent is one of BYK-306, BYK-320, BYK-321, and BYK-346.

[0014] Preferably, the mixed solvent is a mixture of xylene and n-butanol in a mass ratio of 3:1.

[0015] Furthermore, step S1, the preparation of the latent reactive conductive primer slurry, includes: Bisphenol A type epoxy resin and mixed solvent are mixed and stirred at 500-800 rpm at room temperature for 10-20 min. Anti-settling agent is added and dispersed at 1500-1800 rpm for 20-30 min. The stirring speed is adjusted to 800-1000 rpm and zinc powder and conductive carbon black are added. The stirring speed is adjusted to 1500-1800 rpm and dispersed for 40-50 min. The stirring speed is adjusted to 300-500 rpm and leveling agent is added and stirred for 5-10 min to obtain component A. Component A is mixed evenly with modified polyamide curing agent and allowed to stand for 15-20 min to mature to obtain latent reactive conductive primer slurry.

[0016] Furthermore, step S2, which involves applying a latent reactive conductive primer slurry to the substrate surface and then semi-curing it, includes: spraying the latent reactive conductive primer slurry onto the substrate surface and curing it for 10-15 hours at an ambient temperature of 20-30°C and a relative humidity of 50-70% until it reaches a finger-dry state, thus forming a semi-cured latent reactive conductive primer layer.

[0017] Furthermore, the dry film thickness of the semi-cured latent reactive conductive primer layer is 75-85 μm.

[0018] Furthermore, the process parameters for the electrophoretic permeation treatment in step S2 are: bath temperature of 25-35℃, DC voltage of 50-120V, and duration of 3-10min.

[0019] In one specific embodiment, the electrophoretic permeation treatment in step S2 includes: Dissolve aqueous polyetheramine and tetrabutylammonium bromide in deionized water, and adjust the pH of the solution to 4.5-6.0 with glacial acetic acid to obtain an electrolyte containing 30-80g of aqueous polyetheramine and 8-15g of tetrabutylammonium bromide per liter. Set up an electrophoresis apparatus, immerse the semi-cured latent reactive conductive primer layer-substrate as the cathode in the electrolyte, maintain the electrolyte temperature in the electrophoresis tank at 25-35℃, and apply a DC voltage of 50-120V for electrophoretic penetration for 3-10 minutes. The aqueous polyetheramine and tetrabutylammonium bromide in the electrolyte migrate to the cathode and penetrate into the microscopic defects of the semi-cured latent reactive conductive primer slurry. After the electrophoretic penetration is completed, remove the semi-cured latent reactive conductive primer layer-substrate and clean it.

[0020] Preferably, the electrolyte for the electrophoretic permeation treatment contains 50g of aqueous polyetheramine and 10g of tetrabutylammonium bromide per liter, and has a pH value of 5.0.

[0021] This technical solution involves electrophoretic infiltration treatment on a semi-cured latent reactive conductive primer layer. This not only allows the reactive components to penetrate into the micropores of the semi-cured latent reactive conductive primer layer, but also allows an electrophoretic layer to be deposited on its surface. The electrophoretically infiltrated semi-cured latent reactive conductive primer layer and the surface-deposited electrophoretic layer together constitute the electrophoretic latent reactive conductive primer layer. The electrolyte within this concentration range provides the conductivity and reactant concentration required to carry out the electrophoretic process, ensuring the effective implementation of the infiltration process.

[0022] Furthermore, the dry film thickness of the electrophoretic layer in step S2 ranges from 15 to 30 μm.

[0023] Furthermore, the thermosetting process in step S3 includes raising the temperature from room temperature to 110-140°C at a heating rate of 2-5°C / min and maintaining the temperature at that rate for 30-60 minutes.

[0024] By adopting this technical solution, the combination of electrophoresis process parameters and thermosetting procedure can enable the reactive components to fully penetrate and react with epoxy groups, which is beneficial to forming a uniform and dense interpenetrating network structure.

[0025] Furthermore, the topcoat is a two-component polysiloxane topcoat.

[0026] Furthermore, step S4, which involves applying and curing the topcoat over the cured primer layer, includes: Apply the topcoat using an airless spraying method, controlling the dry film thickness of the topcoat layer to be 55-65μm, and allow it to cure naturally for 168 hours.

[0027] Secondly, the present invention provides a weather-resistant and anti-aging protective layer for offshore wind power facilities, which is prepared by the above-mentioned method for preparing the weather-resistant and anti-aging protective layer for offshore wind power facilities.

[0028] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention forms a chemically bonded interpenetrating network structure by reserving active epoxy groups in a semi-cured latent reactive conductive primer layer and initiating in-situ polymerization of waterborne polyetheramine with it in subsequent steps. This structure replaces the physical bonding interface between traditional coatings, fundamentally improving the interfacial bonding strength and hydrolytic stability, enhancing the adhesion of the protective layer in humid and hot environments, and effectively inhibiting interlayer delamination caused by water vapor penetration.

[0029] 2. This invention employs an electrophoretic penetration process, utilizing an electric field to actively drive the migration of functional components and deeply fill the inherent microscopic defects in the semi-cured latent reactive conductive primer layer. Compared to the passive wetting of traditional coating methods, this method achieves a more thorough and dense filling of defects, resulting in a stronger overall protective layer with superior shielding performance, effectively blocking the penetration of corrosive media such as water and chloride ions.

[0030] 3. The protective layer formed by this invention has a stable chemically bonded interface. When the coating surface is physically scratched, this high-strength interfacial bonding force can effectively prevent the corrosive medium from spreading laterally along the interface between the coating and the substrate. This effectively inhibits undercut corrosion at the scratches and significantly improves the long-term protective performance of the coating system under damaged conditions. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the implementation schemes of this invention will be described in detail below with reference to specific embodiments. Unless otherwise defined, the technical and scientific terms used in this invention have the meanings commonly understood by those skilled in the art. Without departing from the concept of this invention, those skilled in the art can make several improvements and changes to the specific embodiments described in this specification, all of which fall within the scope of protection of this invention. Where specific experimental steps or conditions are not specified in the embodiments, conventional experimental steps or conditions described in the literature in this field can be followed.

[0032] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0033] It should be noted that, for the sake of brevity, the room temperature in this invention is 25°C, and the specific room temperature will not be described separately in the following.

[0034] Example 1: This embodiment provides a method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities, including the following steps: S1. Preparation of latent reactive conductive primer slurry, including: S1-1, Preparation of component A: In a clean, dry 5L high-speed dispersion vessel, accurately weigh and add 900.0g of bisphenol A type epoxy resin (E-51) and 540.0g of a pre-mixed solvent of xylene and n-butanol in a mass ratio of 3:1. Start stirring, set the speed to 600rpm, and stir at room temperature for 15min until the epoxy resin is completely dissolved to form a homogeneous and transparent resin solution.

[0035] While stirring, add 45.0g of organic bentonite anti-settling agent to the resin solution, and increase the speed of the dispersion vessel to 1600rpm to disperse for 25min. This step is intended to allow the anti-settling agent to be fully wetted, peeled off and form a three-dimensional network structure in the mixed solvent and resin solution.

[0036] Adjust the rotation speed to 900 rpm and add 1050.0 g of zinc powder and 60.0 g of conductive carbon black. After the addition is complete and the mixture is initially wetted, adjust the rotation speed to 1600 rpm and disperse for 45 minutes. During this period, cooling water is circulated through the jacket to strictly control the temperature of the slurry to not exceed 45°C in order to prevent excessive volatilization of the mixed solvent and possible thermally initiated side reactions.

[0037] Adjust the rotation speed to 400 rpm, take a sample and test it with a scraper fineness gauge to confirm that the fineness reaches below 50 μm. After confirming that it is qualified, add 5.0 g of BYK-320 leveling agent and stir for 8 min. Stop stirring and discharge from the dispersion vessel to obtain 2600 g of component A. Put it into a sealed container, affix a label, and store it in a cool and dry place for later use.

[0038] S1-2. By mass, add 11.7 parts of Aradur 115 modified polyamide curing agent to 100.0 parts of component A (to control the molar ratio of total active hydrogen to total epoxy group at 0.6:1), stir at low speed for 5 minutes at room temperature to mix evenly, and let stand for 20 minutes to mature to obtain latent reactive conductive primer slurry.

[0039] S2. Apply a latent reactive conductive primer slurry to the substrate surface and allow it to partially cure to obtain a semi-cured latent reactive conductive primer layer. Then, perform electrophoretic penetration treatment to obtain an electrophoretic latent reactive conductive primer layer, including: S2-1. Using a Q345E steel plate treated with Sa2.5 grade sandblasting as the substrate, a latent reactive conductive primer slurry is applied to the surface of the steel plate substrate using a high-pressure airless spraying method, resulting in a steel plate substrate coated with the slurry. Subsequently, the steel plate substrate coated with the slurry is naturally cured for 12 hours at an ambient temperature of 25℃ and a relative humidity of 60%, reaching a finger-dry state, forming a semi-cured latent reactive conductive primer layer with a dry film thickness (DFT) of 80μm. The spraying parameters of the high-pressure airless spraying method in step S2-1 meet one or more of the following conditions: working pressure 180-220 bar (approximately 18-22 MPa), nozzle orifice diameter selected 0.017-0.021. The spraying parameters for the high-pressure airless spraying method in the embodiment are: working pressure 200 bar, nozzle model 519, and spraying fan width 30 cm.

[0040] S2-2, Electrophoretic permeation treatment: Electrolyte preparation: Add 8.0 kg of deionized water to the reactor, and while stirring, dissolve the aqueous polyetheramine (Jeffamine) sequentially. ® Dissolve 500.0g of D-400 and 100.0g of tetrabutylammonium bromide (TBAB) completely. Then slowly add glacial acetic acid dropwise while monitoring the pH with a pH meter until the pH of the solution stabilizes at 5.0. Finally, add deionized water to bring the total volume of the solution to 10.0L.

[0041] An electrophoresis apparatus was constructed. A semi-cured latent reactive conductive primer layer-steel plate substrate was used as the cathode and immersed in the electrolyte. A 316L stainless steel plate with an area ratio of 1:3 was used as the anode. Both electrodes were immersed in the electrolyte, and the electrolyte temperature in the electrophoresis tank was controlled at 30℃. An 80V DC voltage was applied for electrophoretic penetration for 5 minutes, forming an electrophoretic layer on the semi-cured latent reactive conductive primer layer with a dry film thickness of 20μm. After electrophoresis, the electrophoretic latent reactive conductive primer layer-steel plate substrate was removed and immediately rinsed with deionized water for 1 minute. Electrophoretic penetration treatment on the semi-cured latent reactive conductive primer layer not only allows the reactive components to penetrate into the micropores of the semi-cured latent reactive conductive primer layer but also deposits an electrophoretic layer on its surface. The electrophoretically penetrated semi-cured latent reactive conductive primer layer and the surface-deposited electrophoretic layer together constitute the electrophoretic latent reactive conductive primer layer.

[0042] S3. Perform a thermosetting treatment on the electrophoretic latent reactive conductive primer layer to obtain a cured primer layer, including: The electrophoretic latent reactive conductive primer layer-steel plate substrate was placed in a programmable temperature controlled oven. The heating program was set to raise the oven temperature from room temperature to 120℃ at a heating rate of 3℃ / min, and then the temperature was kept constant at 120℃ for 45 minutes. After the holding period, the heating power was turned off, and the oven was allowed to cool naturally to room temperature to obtain the cured primer layer-steel plate substrate.

[0043] S4. Apply the topcoat over the cured primer layer and cure it to obtain a weather-resistant and anti-aging protective layer, including: On the surface of the cured primer layer, a two-component polysiloxane topcoat is applied using a high-pressure airless spraying method. The two-component polysiloxane topcoat is model PSX 700. The dry film thickness of the two-component polysiloxane topcoat layer is controlled at 60 μm. It is then naturally cured for 168 hours under standard conditions to obtain a weather-resistant and anti-aging protective layer. The spraying parameters for the high-pressure airless spraying method in step S4 meet one or more of the following conditions: working pressure 150-180 bar (approximately 15-18 MPa), nozzle orifice diameter 0.013-0.015 inch (such as standard nozzle model 413 or 415). In this embodiment, the specific high-pressure airless spraying parameters are: working pressure 150 bar, nozzle model 413.

[0044] Example 2: The difference between this embodiment and Embodiment 1 is that: S1-2. By mass, add 9.7 parts of modified polyamide curing agent to 100.0 parts of component A (to control the molar ratio of total active hydrogen to total epoxy group at 0.5:1), stir at low speed for 5 minutes at room temperature to mix evenly, and let stand for 20 minutes to mature to obtain latent reactive conductive primer slurry.

[0045] S2-2, Electrophoretic permeation treatment: Electrolyte preparation: Add 8.0 kg of deionized water to the reactor, and while stirring, dissolve the aqueous polyetheramine (Jeffamine) sequentially. ® Dissolve 800.0g of D-400 and 80.0g of tetrabutylammonium bromide (TBAB) completely, then slowly add glacial acetic acid dropwise while monitoring the pH with a pH meter until the pH of the solution stabilizes at 4.5. Finally, add deionized water to bring the total volume of the solution to 10.0L.

[0046] An electrophoresis apparatus was constructed. A semi-cured latent reactive conductive primer layer-steel plate substrate was used as the cathode and immersed in the electrolyte. A 316L stainless steel plate with an area ratio of 1:3 was used as the anode. Both electrodes were immersed in the electrolyte. The electrolyte temperature in the electrophoresis tank was controlled at 35℃, and a DC voltage of 120V was applied for electrophoretic penetration for 3 minutes, forming an electrophoretic layer on the semi-cured latent reactive conductive primer layer. The dry film thickness of the electrophoretic layer was 15μm. After electrophoresis, the electrophoretic latent reactive conductive primer layer-steel plate substrate was removed, and the surface was immediately rinsed with deionized water for 1 minute.

[0047] S3. Perform a thermosetting treatment on the electrophoretic latent reactive conductive primer layer to obtain a cured primer layer, including: The electrophoretic latent reactive conductive primer layer-steel plate substrate was placed in a programmable temperature controlled oven. The heating program was set to raise the oven temperature from room temperature to 110℃ at a heating rate of 5℃ / min, and then the temperature was kept constant at 110℃ for 60 minutes. After the holding period, the heating power was turned off, and the oven was allowed to cool naturally to room temperature to obtain the cured primer layer-steel plate substrate.

[0048] Example 3: The difference between this embodiment and Embodiment 1 is that: S1-2. By mass, add 13.6 parts of Aradur 115 modified polyamide curing agent to 100.0 parts of component A (to control the molar ratio of total active hydrogen to total epoxy group at 0.7:1), stir at low speed for 5 minutes at room temperature to mix evenly, and let stand for 20 minutes to mature to obtain latent reactive conductive primer slurry.

[0049] S2-2, Electrophoretic permeation treatment: Electrolyte preparation: Add 8.0 kg of deionized water to the reactor, and while stirring, dissolve the aqueous polyetheramine (Jeffamine) sequentially. ®Dissolve 300.0g of D-400 and 150.0g of tetrabutylammonium bromide (TBAB) completely, then slowly add glacial acetic acid dropwise while monitoring the pH with a pH meter until the solution pH stabilizes at 6.0. Finally, add deionized water to bring the total solution volume to 10.0L.

[0050] An electrophoresis apparatus was constructed. A semi-cured latent reactive conductive primer layer-steel plate substrate was used as the cathode and immersed in the electrolyte. A 316L stainless steel plate with an area ratio of 1:3 was used as the anode. Both electrodes were immersed in the electrolyte. The electrolyte temperature in the electrophoresis tank was controlled at 25°C, and a DC voltage of 50V was applied for electrophoretic penetration for 10 minutes, forming an electrophoretic layer on the semi-cured latent reactive conductive primer layer. The dry film thickness of the electrophoretic layer was 25μm. After electrophoresis, the electrophoretic latent reactive conductive primer layer-steel plate substrate was removed, and the surface was immediately rinsed with deionized water for 1 minute.

[0051] S3. Perform a thermosetting treatment on the electrophoretic latent reactive conductive primer layer to obtain a cured primer layer, including: The electrophoretic latent reactive conductive primer layer-steel plate substrate was placed in a programmable temperature controlled oven. The heating program was set to raise the oven temperature from room temperature to 140℃ at a heating rate of 2℃ / min, and then the temperature was kept constant at 140℃ for 30 minutes. After the holding period, the heating power was turned off, and the oven was allowed to cool naturally to room temperature to obtain the cured primer layer-steel plate substrate.

[0052] Example 4: The difference between this embodiment and Embodiment 1 is that: S1-1, Preparation of component A: In a clean, dry 5L high-speed dispersion vessel, accurately weigh and add 800.0g of bisphenol A type epoxy resin (E-51) and 400.0g of a mixed solvent premixed from xylene and n-butanol at a mass ratio of 2.5:1. Start stirring, set the speed to 500 rpm, and stir at room temperature for 20 minutes until the epoxy resin is completely dissolved, forming a homogeneous and transparent resin solution.

[0053] While stirring, add 30.0g of organic bentonite anti-settling agent to the resin solution, and increase the speed of the dispersion vessel to 1500rpm and disperse for 30min. This step is intended to allow the anti-settling agent to be fully wetted, peeled off and form a three-dimensional network structure in the mixed solvent and resin solution.

[0054] Adjust the rotation speed to 800 rpm and add 900.0 g of zinc powder and 40.0 g of conductive carbon black. After the addition is complete and the mixture is initially wetted, adjust the rotation speed to 1800 rpm and disperse for 40 minutes. During this period, cooling water is circulated through the jacket to strictly control the temperature of the slurry to not exceed 45°C in order to prevent excessive volatilization of the mixed solvent and possible thermally initiated side reactions.

[0055] Adjust the rotation speed to 300 rpm, take a sample and test it with a scraper fineness gauge to confirm that the fineness reaches below 50 μm. After confirming that it is qualified, add 3.0 g of BYK-306 leveling agent and stir for 10 min. Stop stirring and discharge from the dispersion vessel to obtain 2173 g of component A. Put it into a sealed container, affix a label, and store it in a cool and dry place for later use.

[0056] S1-2. By mass, add 11.7 parts of Aradur 115 modified polyamide curing agent to 100.0 parts of component A (to control the molar ratio of total active hydrogen to total epoxy group at 0.6:1), stir at low speed for 5 minutes at room temperature to mix evenly, and let stand for 15 minutes to mature to obtain latent reactive conductive primer slurry.

[0057] S2-1. The steel plate substrate coated with the slurry is naturally cured for 15 hours at an ambient temperature of 20℃ and a relative humidity of 50% to reach the finger-dry state, forming a semi-cured latent reactive conductive primer layer with a dry film thickness (DFT) of 75μm.

[0058] S4. Control the dry film thickness of the two-component polysiloxane topcoat layer to 55μm.

[0059] Example 5: The difference between this embodiment and Embodiment 1 is that: S1-1, Preparation of component A: In a clean, dry 5L high-speed dispersion vessel, accurately weigh and add 1000.0g of bisphenol A type epoxy resin (E-51) and 600.0g of a pre-mixed solvent of xylene and n-butanol in a mass ratio of 3.5:1. Start stirring, set the speed to 800 rpm, and stir at room temperature for 10 minutes until the epoxy resin is completely dissolved to form a homogeneous and transparent resin solution.

[0060] While stirring, add 60.0g of organic bentonite anti-settling agent to the resin solution, and increase the speed of the dispersion vessel to 1800rpm for 20min. This step is intended to allow the anti-settling agent to be fully wetted, peeled off and form a three-dimensional network structure in the mixed solvent and resin solution.

[0061] Adjust the rotation speed to 1000 rpm and add 1200.0 g of zinc powder and 80.0 g of conductive carbon black. After the addition is complete and the mixture is initially moistened, adjust the rotation speed to 1500 rpm and disperse for 50 minutes. During this period, cooling water is circulated through the jacket to strictly control the temperature of the slurry to not exceed 45℃ in order to prevent excessive volatilization of the mixed solvent and possible thermally initiated side reactions.

[0062] Adjust the rotation speed to 500 rpm, take a sample and test it with a scraper fineness gauge to confirm that the fineness reaches below 50 μm. After confirming that it is qualified, add 7.0 g of BYK-321 leveling agent and stir for 5 min. Stop stirring and discharge from the dispersion vessel to obtain 2947 g of component A. Put it into a sealed container, affix a label, and store it in a cool and dry place for later use.

[0063] S2-1. The steel plate substrate coated with the slurry is naturally cured for 10 hours at an ambient temperature of 30℃ and a relative humidity of 70% to reach the finger-dry state, forming a semi-cured latent reactive conductive primer layer with a dry film thickness (DFT) of 85μm.

[0064] S4. Control the dry film thickness of the two-component polysiloxane topcoat layer to 65μm.

[0065] Example 6: The difference between this embodiment and Embodiment 1 is that: S1-1, Add 5.0g of BYK-346 leveling agent and stir for 5 minutes.

[0066] Comparative Example 1: This comparative example provides a conventional heavy-duty anti-corrosion coating for benchmark performance comparison with the overall technical solution of this invention. Its preparation steps are as follows: (1) On the Q345E steel plate substrate treated with Sa2.5 grade sandblasting, spray conventional zinc-rich epoxy primer (solid content ≥80%), and the dry film thickness after complete curing is 80μm.

[0067] (2) Spray conventional epoxy intermediate paint (high solids) on the primer. The dry film thickness after complete curing is 120μm.

[0068] (3) Spray conventional polysiloxane topcoat on the intermediate paint. After complete curing, the dry film thickness is 60μm, and a heavy-duty anti-corrosion coating-steel plate substrate is obtained.

[0069] Comparative Example 2: The difference compared to Example 1 is that tetrabutylammonium bromide is not added to the electrolyte.

[0070] Comparative Example 3: The difference compared to Example 1 is as follows: S1-2. By mass, add 13.6 parts of Aradur 115 modified polyamide curing agent to 100.0 parts of component A (to control the molar ratio of total active hydrogen to total epoxy group at 0.7:1), stir at low speed for 5 minutes at room temperature to mix evenly, and let stand for 20 minutes to mature to obtain primer slurry.

[0071] Replace step S2 with applying a primer slurry to the substrate surface and allowing it to fully cure under standard conditions for 168 hours to form an inert, non-reactive primer layer; then electrophoretically apply a commercially available conventional cathodic acrylic electrophoretic primer to the primer layer to obtain an electrophoretic primer layer-steel substrate. Replace step S3 with baking and curing the electrophoretic primer layer-steel substrate obtained in step S2 at 180°C for 30 minutes to obtain the cured primer layer-steel substrate.

[0072] Comparative Example 4: The difference compared to Example 1 is as follows: The electrophoretic penetration treatment in step S2-2 is replaced with a conventional spraying process, including: maintaining the same mass ratio of aqueous polyetheramine and tetrabutylammonium bromide as in Example 1, dissolving aqueous polyetheramine and tetrabutylammonium bromide in ethylene glycol butyl ether solvent to prepare a spraying solution, wherein the mass ratio of solute (sum of mass of aqueous polyetheramine and tetrabutylammonium bromide) to solvent (ethylene glycol butyl ether) in the spraying solution is 3:7, and applying it to the surface of the semi-cured latent reactive conductive primer layer by air spraying to form an intermediate layer, controlling the wet film thickness of the sprayed layer to be about 40μm, to obtain the intermediate layer - semi-cured latent reactive conductive primer layer - steel plate substrate.

[0073] Step S3 involves performing a thermosetting process on the intermediate layer-semi-cured latent reactive conductive primer layer-steel substrate according to the parameters of Example 1 to obtain a cured intermediate layer-primer layer-steel substrate.

[0074] Test Example 1: Electrochemical Impedance Spectroscopy (EIS) Test Objective: This test aims to quantitatively evaluate the shielding performance of the protective layer using the electrochemical impedance spectroscopy method, thereby verifying the effectiveness of the electrophoretic penetration process used in this invention compared with the conventional spraying process in filling and repairing the inherent microscopic defects of latent reactive conductive primer slurry.

[0075] Test subject: Sample No. 1: Cured primer layer of Example 1, step S3 - steel plate substrate, without topcoat application.

[0076] Sample No. 2: Comparative Example 4, Step S3, Curing Intermediate Layer - Primer Layer - Steel Substrate, without Topcoat Application.

[0077] Instruments and equipment: Electrochemical workstation: CorrTest CS350 or equivalent.

[0078] Three-electrode corrosion cell: includes working electrode fixture, platinum sheet counter electrode and saturated calomel reference electrode (SCE).

[0079] Test media: analytical grade sodium chloride (NaCl) and deionized water.

[0080] Masking tape: 3M anti-corrosion tape, used to define the test area.

[0081] Test steps: Sample preparation: Three parallel samples were taken from each of the coated steel plates of Sample 1 (Example 1) and Sample 2 (Comparative Example 4). Masking tape was used to define a 10.0 cm² area on the surface of each sample. 2 The circular test area.

[0082] Electrolyte preparation: Weigh 35.0g of sodium chloride and dissolve it in 965.0g of deionized water to prepare a 3.5% NaCl solution as the test electrolyte.

[0083] Electrochemical cell assembly: The prepared sample is installed as the working electrode in the corrosion cell, ensuring that the test area is in full contact with the electrolyte and is well sealed. A 3.5% NaCl solution is injected into the cell, and a platinum sheet counter electrode and a saturated calomel reference electrode are placed inside.

[0084] Open circuit potential stability: Before conducting impedance spectroscopy tests, the entire three-electrode system is immersed in the electrolyte for 30-60 minutes. The open circuit potential (OCP) of the working electrode is monitored. When the fluctuation range of the OCP within 600 seconds is less than 5mV, the system is considered to have reached stability.

[0085] Impedance spectrum data acquisition: Based on a stable open circuit potential, a sinusoidal AC voltage disturbance signal with an amplitude of 20mV is applied, and the scanning frequency range is set from 100kHz to 0.01Hz. Impedance data at each frequency are acquired and recorded.

[0086] Experimental data: The low-frequency impedance modulus of the coating system is a key indicator for evaluating its shielding performance against corrosive media. The higher the value, the better the density of the coating and the fewer penetrating defects it contains. The specific electrochemical impedance spectroscopy test results are shown in Table 1:

[0087] Conclusion: Electrochemical impedance spectroscopy results show that the low-frequency impedance modulus of sample 1 (Example 1) is within 10. 10 -10 11 Ohm·cm 2 The value is on the order of magnitude, while that of sample 2 (Comparative Example 4) is around 10. 7 -10 8 Ohm·cm 2 Order of magnitude. There is a significant difference of 2 to 3 orders of magnitude between the two.

[0088] In electrochemical theory, the low-frequency impedance modulus of the coating directly reflects its integrity as a physical barrier. The significant increase in impedance value indicates that the coating system of Example 1 has formed a denser and more continuous structure with very few conductive pathways (i.e., micro-defects) that allow electrolytes and ions to pass through.

[0089] This result stems from process differences. In Example 1, the electric field drives the charged reactive components (aqueous polyetheramine and tetrabutylammonium bromide) to actively and directionally migrate and penetrate deep into the inherent pinholes, microcracks, and other defects in the latent reactive conductive primer slurry, achieving effective physical filling of these microscopic defects. In contrast, in the conventional spraying process used in Comparative Example 4, the prepared spray liquid passively covers the primer surface relying solely on its own wetting and flowability, resulting in limited filling ability for narrow and deep defects and the tendency to leave penetrating pores after curing.

[0090] Therefore, the data from this test case strongly demonstrates that the electrophoretic permeation step used in this invention is the key to constructing a highly dense, low-defect integrated protective layer, and its effect is significantly better than conventional construction methods.

[0091] Test Example 2: Interface Bonding Mode Verification (Dry / Wet Adhesion Test) Objective: This test aims to verify the effectiveness of the chemical bonding formed by in-situ interfacial polymerization in resisting water vapor erosion and maintaining interfacial stability, compared with traditional physical bonding interfaces, by comparing the coating adhesion and failure modes under dry and wet environments.

[0092] Test subject: Sample No. 1: Cured primer layer of Example 1, step S3 - steel plate substrate, without topcoat application.

[0093] Sample No. 3: Comparative Example 3, Step S3 cured primer layer - steel plate substrate, no topcoat applied.

[0094] Instruments and equipment: Pull-off adhesion tester: Elcometer 510 or equivalent equipment, conforming to ISO 4624 / ASTM D4541 standards.

[0095] Test spindle (Dolly): 20mm diameter standard spindle.

[0096] Epoxy structural adhesive: Araldite ® Two-component epoxy adhesives of 2011 or equivalent performance.

[0097] Spindle cutter: Used to cut the coating along the edge of the spindle to the substrate.

[0098] Constant temperature water bath: Temperature control accuracy ±1℃.

[0099] Test steps: Sample preparation: Six parallel samples were taken from the coated steel plates of Sample 1 (Example 1) and Sample 3 (Comparative Example 3) and divided into dry test group and wet test group, with three samples in each group.

[0100] Spindle bonding: Clean the sample test area and spindle bonding surface with acetone or isopropanol. Apply epoxy structural adhesive evenly to the spindle surface, press vertically onto the sample test area, and remove any excess adhesive. Cure at room temperature for at least 24 hours.

[0101] Coating cutting: Using a spindle cutter, the coating is precisely cut along the outer edge of each spindle to the steel substrate to isolate the test area.

[0102] Environmental treatment: Dry test group: The samples with the bonded spindles are directly subjected to subsequent adhesion tests.

[0103] Wet test group: The bonded spindle sample was completely immersed in deionized water at 60°C and continuously soaked in a constant temperature water bath for 480 hours. After removal, the surface moisture was quickly wiped dry, and the adhesion test was completed within 1 hour.

[0104] Pull-off test: Connect the pull-out head of the adhesion tester to the spindle. Apply a load steadily and vertically at a rate of 0.2 MPa / s until the spindle is pulled off the substrate surface. Record the maximum pull-off strength (MPa).

[0105] Failure Mode Analysis: Observe the failure interface between the bottom surface of the pulled-out spindle and the surface of the sample, and record the failure mode according to ISO 4624 standard.

[0106] Experimental data: Record the tensile strength and failure mode of each sample, and calculate the wet adhesion retention rate ([wet average strength / dry average strength] × 100%).

[0107] The dry / wet adhesion test results for Test Example 2 are shown in Table 2:

[0108] Note: Adhesion retention rate is calculated based on the average strength under dry and wet conditions; "-" in the table indicates that this item is not applicable or not available.

[0109] Conclusion: The dry / wet adhesion test results showed that Sample 1 (Example 1) maintained an adhesion retention rate of 81.5% after immersion in humid heat, and its failure mode, regardless of whether it was dry or wet, was mainly cohesive failure of the primer layer. This indicates that the interfacial bonding strength of Example 1 is higher than the cohesive strength of its coating itself. In contrast, Sample 3 (Comparative Example 3) showed a severe decrease in adhesion after immersion in humid heat, with a retention rate of only 36.0%. Its failure mode clearly pointed to the interface between the primer and the electrophoretic coating layer, which is a typical interlayer adhesion failure.

[0110] This result reflects the difference in the interfacial bonding mechanisms of the two systems. In Example 1, through in-situ interfacial polymerization, numerous chemical bonds were formed between the latent reactive conductive primer slurry and the penetrating reactive components, constructing a gradient interpenetrating network without a clear physical interface. This chemical bonding exhibits strong resistance to water molecule intrusion and hydrolysis, maintaining high binding strength even in a wet state.

[0111] The interface in Comparative Example 3 is based on physical adsorption and mechanical interlocking after the coating has cured. Under humid and hot conditions, this physical force is easily destroyed by water molecules that penetrate to the interface, resulting in a rapid and significant loss of interfacial bonding.

[0112] Therefore, the data from this test case confirms that the in-situ interfacial polymerization process used in this invention can construct a chemically bonded and stable interface, fundamentally solving the technical problem of weak physical interfaces and susceptibility to moisture-induced failure in traditional multi-coating systems.

[0113] Test Example 3: Accelerated Corrosion Performance Evaluation (Neutral Salt Spray Test) Objective: This test aims to evaluate the ability of the protective system to inhibit the lateral propagation of corrosive media along the coating / substrate interface in the presence of macroscopic physical damage (scratches) through accelerated aging tests using neutral salt spray (NSS), thereby verifying the superiority of the integrated protective layer constructed in this scheme in terms of macroscopic long-term protective performance.

[0114] Test subject: Sample No. 4: Example 1: Weather-resistant and anti-aging protective layer containing a complete protective layer - steel plate substrate sample.

[0115] Sample No. 5: Heavy-duty anti-corrosion coating of steel plate substrate as a comparative example 1.

[0116] Instruments and equipment: Neutral salt spray test chamber: conforms to ASTM B117 and ISO 9227 standards.

[0117] Marking tool: Carbide marking tool conforming to ISO 17872 standard.

[0118] Digital microscope or graduated magnifying glass: used for precise measurement of corrosion spread width.

[0119] Analytical grade sodium chloride (NaCl) and deionized water.

[0120] Test steps: Sample preparation: Three parallel samples were taken from the final coated steel plates of sample 4 (Example 1) and sample 5 (Comparative Example 1).

[0121] Artificial scratching: Using a scribing tool, make a 100mm long and 0.5mm wide scratch in the center of each sample to ensure that the scratch depth accurately reaches the surface of the steel substrate.

[0122] Salt spray exposure: Place the scratched sample on the sample rack of the salt spray test chamber at a 15-30° angle to the vertical direction, with the scratch direction parallel to the mainstream spray direction. Perform continuous spray testing according to ASTM B117 standard, with the following test conditions: 5% NaCl solution, pH 6.5-7.2, and chamber temperature 35±2℃.

[0123] Periodic observation and final evaluation: The total test duration was set at 1000 hours. After the test, the samples were removed, and the surface salt deposits were gently rinsed with running water and allowed to air dry for 24 hours. The maximum single-sided expansion width of the corrosion products on both sides of the scratch was measured and recorded using a digital microscope. Simultaneously, the blistering level of the sample surface was evaluated according to ISO 4628-2 standard.

[0124] Experimental data: After 1000 hours of salt spray testing, the maximum single-sided corrosion spread width and surface blistering at the scratches of each sample were recorded. The specific results of the neutral salt spray test are shown in Table 3.

[0125] Note: Foaming grade 10(0) means no foaming; 8-S3 means foam size is grade 3 and density is grade 8; S represents size grade.

[0126] Conclusion: The neutral salt spray test results showed that after 1000 hours of neutral salt spray exposure, the scratch corrosion propagation width of sample 4 (Example 1) was controlled within 0.51 mm, and no blistering occurred on the paint film surface. Sample 5 (Comparative Example 1) showed scratch corrosion propagation exceeding 5 mm to both sides, and blistering of the paint film occurred. The lateral propagation of corrosion is an electrochemical process occurring along the coating-substrate interface, and its propagation rate is affected by the interfacial bonding stability and the coating's shielding ability against corrosive media (water, oxygen, chloride ions).

[0127] The results of this test case confirm the technical mechanism of this solution: Inhibiting Interfacial Corrosion Propagation: Example 1 constructed a chemically bonded gradient interpenetrating network between the primer and the penetrating layer through in-situ interfacial polymerization. This chemically bonded interface improved the adhesion stability of the coating in humid environments, prevented corrosive media from penetrating along the interface, and confined corrosion to the scratched exposed metal area, thereby inhibiting lateral propagation. Comparative Example 1, with its physically bonded interface, was prone to peeling under corrosive media, providing a channel for corrosion propagation.

[0128] Preventing paint film blistering: Paint film blistering originates from localized osmotic pressure. Example 1 uses an electrophoretic penetration process to fill the inherent defects of the primer, forming a highly dense protective layer (as confirmed by EIS data from Test Example 1). This layer hinders the penetration of moisture and ions and does not create osmotic pressure sufficient to cause blistering.

[0129] In summary, this test case demonstrates from the perspective of long-term accelerated corrosion performance that the integrated protection system constructed in this invention effectively inhibits the spread of corrosion at the damaged site by strengthening the interface bonding and improving the coating density, and its comprehensive protection performance is superior to that of traditional multi-coating systems.

[0130] Test Example 4: Interface Compatibility and Network Structure Characterization (Dynamic Thermomechanical Analysis) Objective: This test uses dynamic thermomechanical analysis (DMA) to evaluate the glass transition behavior of the coating system, characterize the compatibility and network interpenetration structure of the interface region in Example 1, and compare it with the physical layer structure of the comparative example.

[0131] Test subject: To perform DMA testing, a self-supporting coating sample without a substrate needs to be prepared: Sample No. 6: The latent reactive conductive primer slurry that was cured into a film separately in Example 1, i.e., the primer.

[0132] Sample No. 7: Electrophoretic latent reactive conductive primer layer cured separately in Example 1, i.e., electrophoretic paint.

[0133] Sample No. 8: The cured primer layer of step S3 in Example 1, namely the primer electrophoretic paint composite film.

[0134] Sample No. 9: The cured primer layer of Comparative Example 3, i.e., the primer electrophoretic paint composite film.

[0135] Instruments and equipment: Dynamic Thermomechanical Analyzer (DMA): TA Instruments Q800 or equivalent equipment, equipped with tensile clamps, coating preparation device, precision thickness gauge, and sample cutter.

[0136] Test steps: Preparation of self-supporting film: On a non-stick substrate, a coating is prepared according to the requirements of each test object. After curing, it is carefully peeled off to obtain a self-supporting coating with uniform thickness (about 100 μm). The non-stick substrate can be a PTFE (Polytetrafluoroethylene) plate.

[0137] Sample cutting: Cut each coating film to the standard size required for DMA testing (e.g., 5 mm wide and 25 mm long).

[0138] DMA Test: The sample is clamped in the tensile mode fixture of the DMA. The test program is set as follows: a heating rate of 3℃ / min, scanning from -20℃ to 180℃, a test frequency of 1Hz, and a strain of 0.1%. The instrument software automatically analyzes the data and outputs the thermodynamic transition temperature (Tg) at which the material undergoes its glass transition.

[0139] Data analysis: Record the values ​​of one or more glass transition temperatures (Tg) for each sample reported by the instrument.

[0140] Experimental data: The glass transition temperatures of each sample during the DMA test were recorded. The specific dynamic thermomechanical analysis results are shown in Table 4.

[0141] Conclusion: Dynamic thermomechanical analysis confirmed the structural differences between the coatings of Example 1 and Comparative Example 3. For reference, the glass transition temperatures (Tg) of sample 6 (primer of Example 1) and sample 7 (electrophoretic paint of Example 1) were 78.3℃ and 121.8℃, respectively.

[0142] Sample 9 (Comparative Example 3 primer electrophoretic coating composite film) exhibits two independent glass transition temperatures (Tg), namely 79.1℃ and 120.6℃, which are basically consistent with the glass transition temperatures (Tg) of each component, indicating that it is a two-phase separated physical layered structure. In contrast, Sample 8 (Example 1 primer electrophoretic coating composite film) only exhibits a single glass transition temperature (Tg) between the two, namely 103.5℃, which is characteristic of the polymer forming a homogeneous, integrated network.

[0143] The above results confirm the technical mechanism of this solution: the electrophoretic components penetrate into the primer network and, after synergistic curing, form a gradient interpenetrating network structure without phase interfaces. This integrated structure explains the system's high wet adhesion (confirmed by Test Example 2) and its ability to inhibit corrosion propagation (confirmed by Test Example 3).

[0144] Test Example 5: Verification of the effectiveness of the catalytic component in in-situ interfacial polymerization Objective: This test compares the performance of coating systems with and without the catalytic component tetrabutylammonium bromide to verify the necessity of this component for initiating in-situ interfacial polymerization and forming chemically bonded interfaces.

[0145] Test subject: Sample No. 4: Example 1: Weather-resistant and anti-aging protective layer containing a complete protective layer - steel plate substrate sample.

[0146] Sample No. 10: Comparative Example 2, a weather-resistant and anti-aging protective layer containing a complete protective layer - steel plate substrate sample, without the catalytic component tetrabutylammonium bromide.

[0147] Instruments and equipment: Pull-off adhesion tester: Elcometer 510 (Eco 510 Automatic Pull-off Adhesion Tester) or equivalent equipment.

[0148] Constant temperature water bath: Temperature control accuracy ±1℃.

[0149] Test spindles, epoxy structural adhesives, and spindle cutters.

[0150] Test steps: Sample grouping: Three parallel samples were taken from the final coated steel plates of Example 1 and Comparative Example 2.

[0151] Environmental treatment: All samples were completely immersed in deionized water at 60°C and continuously soaked in a constant temperature water bath for 480 hours. This step was designed to accelerate the assessment of the long-term moisture resistance of the coating interface.

[0152] Wet adhesion test: Pull-off adhesion test was conducted according to ASTM D4541 standard. Samples were removed from the water bath, surface moisture was wiped off, and spindle bonding, curing, and pull-off tests were completed within 1 hour using a fast-curing adhesive. The pull-off strength (MPa) and failure mode were recorded for each sample. Failure mode B was defined as cohesive failure of the primer, and B / C was defined as interfacial adhesion failure between the primer and the subsequent penetrating layer.

[0153] Experimental data: The tensile strength and failure mode of each sample were recorded after 480 hours of wet heat immersion. The effect of the catalyst tetrabutylammonium bromide on the wet adhesion and failure mode of the system in Test Example 5 is shown in Table 5.

[0154] Conclusion: The results show that after wet heat aging, the wet adhesion strength of sample 4 (Example 1, containing the catalytic component tetrabutylammonium bromide) remained at approximately 10 MPa, with the failure mode being cohesive failure within the primer. This indicates that its interfacial bonding strength is higher than that of the coating cohesive strength. In contrast, the wet adhesion strength of sample 10 (Comparative Example 2, without the catalytic component tetrabutylammonium bromide) decreased by nearly 50%, and the failure mode shifted to interfacial failure between the primer and the electrophoretic penetration layer.

[0155] This performance difference directly reflects the fundamental difference in the interfacial bonding mechanism between the two systems and confirms the key role of tetrabutylammonium bromide (catalytic component): In-situ polymerization was achieved as follows: In Example 1, tetrabutylammonium bromide served as a phase transfer catalyst, catalyzing the ring-opening addition reaction between the aqueous polyetheramine amine groups that had penetrated into the primer network and the unreacted epoxy groups of the primer. This in-situ polymerization reaction formed a large number of chemical bonds, constructing a stable gradient interpenetrating network. This chemically bonded interface exhibited high resistance to water erosion, thereby maintaining a high level of wet adhesion.

[0156] Physical Retention Limitations: In Comparative Example 2, due to the lack of a catalyst, the aforementioned ring-opening addition reaction was kinetically limited at the final curing temperature and failed to occur effectively. Therefore, the waterborne polyetheramine remained physically within the primer pores. This physical entanglement force is weak and easily disrupted by penetrating water molecules, leading to a rapid loss of interfacial bonding and ultimately interlayer delamination.

[0157] In summary, this test case, by removing the catalyst as a single variable, verifies that the in-situ interfacial polymerization reaction is the key reason for the excellent wet adhesion obtained by this scheme, and confirms that the catalytic component tetrabutylammonium bromide is a necessary component to realize this core technical mechanism.

[0158] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects.

[0159] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be used to limit the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention fall within the scope of protection of this invention.

Claims

1. A method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities, characterized in that, Includes the following steps: A latent reactive conductive primer slurry is prepared; the latent reactive conductive primer slurry is composed of component A and modified polyamide curing agent mixed at a mass ratio of 100:(9.7-13.6); component A contains, by mass, 800-1000 parts of bisphenol A type epoxy resin, 400-600 parts of mixed solvent, 30-60 parts of anti-settling agent, 900-1200 parts of zinc powder, 40-80 parts of conductive carbon black, and 3-7 parts of leveling agent; A latent reactive conductive primer slurry is applied to the substrate surface and semi-cured to obtain a semi-cured latent reactive conductive primer layer. An electrophoretic penetration treatment is then performed on the semi-cured latent reactive conductive primer layer to form an electrophoretic layer, resulting in an electrophoretic latent reactive conductive primer layer. The electrolyte for the electrophoretic penetration treatment contains 30-80g of aqueous polyetheramine and 8-15g of tetrabutylammonium bromide per liter, with a pH value of 4.5-6.

0. The electrophoretic latent reactive conductive primer layer is subjected to thermal curing treatment to obtain a cured primer layer; Apply the topcoat over the cured primer layer and cure it to obtain a weather-resistant and anti-aging protective layer.

2. The method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities according to claim 1, characterized in that, Component A contains, by weight, 900 parts of bisphenol A type epoxy resin, 540 parts of mixed solvent, 45 parts of anti-settling agent, 1050 parts of zinc powder, 60 parts of conductive carbon black, and 5 parts of leveling agent.

3. The method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities according to claim 1, characterized in that, The preparation of the latent reactive conductive primer slurry includes: Bisphenol A type epoxy resin and mixed solvent are mixed and stirred at 500-800 rpm at room temperature for 10-20 min. Anti-settling agent is added and dispersed at 1500-1800 rpm for 20-30 min. The stirring speed is adjusted to 800-1000 rpm and zinc powder and conductive carbon black are added. The stirring speed is adjusted to 1500-1800 rpm and dispersed for 40-50 min. The stirring speed is adjusted to 300-500 rpm and leveling agent is added and stirred for 5-10 min to obtain component A. Component A is mixed evenly with modified polyamide curing agent and allowed to stand for 15-20 min to mature to obtain latent reactive conductive primer slurry.

4. The method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities according to claim 1, characterized in that, Component A contains one or more of the following characteristics: The mixed solvent is a mixture of xylene and n-butanol in a mass ratio of (2.5-3.5):1; The anti-settling agent is organic bentonite; The leveling agent is one of BYK-306, BYK-320, BYK-321, and BYK-346.

5. The method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities according to claim 1, characterized in that, The process of applying a latent reactive conductive primer slurry to the substrate surface and then semi-curing it includes: The latent reactive conductive primer slurry is sprayed onto the surface of the substrate and cured for 10-15 hours at an ambient temperature of 20-30℃ and a relative humidity of 50-70% to form a semi-cured latent reactive conductive primer layer; the dry film thickness of the semi-cured latent reactive conductive primer layer is 75-85μm.

6. The method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities according to claim 1, characterized in that, The process parameters for the electrophoretic permeation treatment are: bath temperature of 25-35℃, DC voltage of 50-120V, and duration of 3-10min.

7. The method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities according to claim 1, characterized in that, The thermosetting process includes raising the temperature from room temperature to 110-140°C at a heating rate of 2-5°C / min and maintaining the temperature at that rate for 30-60 minutes.

8. The method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities according to claim 1, characterized in that, The topcoat is a two-component polysiloxane topcoat.

9. The method for preparing a weather-resistant and anti-aging protective layer for offshore wind power facilities according to claim 1, characterized in that, The process of applying and curing the topcoat over the cured primer layer includes: Apply the topcoat using an airless spraying method, controlling the dry film thickness of the topcoat layer to be 55-65μm, and allow it to cure naturally for 168 hours.

10. A weather-resistant and anti-aging protective layer for offshore wind power facilities, characterized in that, The protective layer for weather resistance and anti-aging of offshore wind power facilities is prepared by the method described in any one of claims 1-9.

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