Microcapsule type epoxy coating with dual functions of self-repairing and anti-corrosion, and preparation method and application thereof

Abstract

The application discloses a microcapsule type epoxy coating with double functions of self-repairing and corrosion prevention and a preparation method and application thereof. An amine curing agent and polyaniline are ultrasonically dispersed under specific conditions to form a core liquid to be wrapped; the core liquid is atomized under a static voltage of 10-25 kV to form core liquid microdroplets; the core liquid microdroplets are received by a reaction solution containing a low-level solvent, a surfactant and HMDI to form nascent microcapsules; the mixture containing the nascent microcapsules and the reaction solution is reacted to obtain microcapsules containing the amine curing agent and the polyaniline; and the microcapsules containing epoxy resin monomers and the microcapsules containing the amine curing agent and the polyaniline are added into an epoxy resin to obtain the microcapsule type epoxy coating with the double functions of self-repairing and corrosion prevention. The application forms the epoxy coating with the double functions of self-repairing and corrosion prevention based on the microcapsules by adding the excellent two-component microcapsules into the commercialized epoxy resin.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and in particular to a microcapsule-based epoxy coating having dual functions of self-repairing and anti-corrosion. Background Art

[0002] In modern industry, coating anti-corrosion technology plays a vital role. With the continuous development of infrastructure and equipment, the demand for anti-corrosion coatings is increasing, especially in the petrochemical, marine engineering, and construction industries. Traditional anti-corrosion coatings are mostly based on epoxy resins, which are widely used due to their excellent adhesion, chemical stability, and mechanical strength. However, epoxy coatings still face problems such as scratches, cracks, and peeling during use, which greatly reduces the protective effectiveness of the coating and leads to corrosion and damage to the substrate.

[0003] To address this issue, researchers have begun exploring self-healing coating technology. Self-healing coatings utilize the self-healing capabilities of their internal materials to automatically repair coating damage caused by external factors, thereby extending the coating's service life. In recent years, the application of microencapsulation technology has provided new insights into self-healing coatings. Microcapsules encapsulate a repair agent. When the coating is damaged, the microcapsules rupture and release the agent, enabling self-repair. However, relying solely on this self-healing mechanism often fails to fully meet corrosion protection requirements.

[0004] Chinese Patent No. 201910649137.2 discloses a method for preparing a self-healing and anti-corrosion coating. The method comprises the following steps: Step 1: preparing an oil-in-water (O / W) emulsion containing a repair agent, which is then crosslinked by radiation or thermal crosslinking to form a microcapsule shell; Step 2: adding aniline dropwise to the dispersion of the microcapsule shell obtained in Step 1, followed by an aqueous solution containing an aniline initiator, to react to produce polyaniline microcapsules; and Step 3: mixing the polyaniline microcapsules with a matrix resin to produce the self-healing and anti-corrosion coating. Specifically, the strong electrostatic interaction between the aniline monomer and the emulsifier molecules fixes the aniline to the surface of the emulsion droplets, allowing the aniline to polymerize and dope on the surface of the emulsion droplets, resulting in a layer of polyaniline microcapsule shells with the repair agent loaded into the core. However, the disadvantage of this method is that the anti-corrosion polyaniline is located within the capsule material, where it is grown in situ and encapsulated in the matrix coating. This makes it difficult for the polyaniline to diffuse into cracks when they form, thus hindering its effectiveness in preventing corrosion. Summary of the Invention

[0005] One of the objectives of this invention is to provide a microcapsule-based epoxy coating that exhibits both self-healing and corrosion protection. By combining microcapsules containing epoxy monomers with microcapsules containing both an amine curing agent and polyaniline, a coating with both self-healing and corrosion protection is formed. This technology not only enables the coating's self-healing function but also significantly improves its corrosion resistance while greatly simplifying the curing and molding process.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for preparing a microcapsule-type epoxy coating having dual functions of self-repair and anti-corrosion comprises the following steps:

[0008] (1) ultrasonically dispersing an amine curing agent and polyaniline in a water bath at 60±20° C. for 60±20 min to uniformly form a core liquid to be coated; atomizing the core liquid under an electrostatic voltage of 10-25 kV to form core liquid microdroplets;

[0009] (2) using a reaction solution containing a low-grade solvent, a surfactant, and HMDI to receive the core liquid microdroplets to form primary microcapsules; reacting the mixture containing the primary microcapsules and the reaction solution at 50±10° C. for 6±2 h, washing, filtering, and drying to obtain microcapsules containing an amine curing agent and polyaniline;

[0010] (3) Adding microcapsules containing epoxy resin monomers and microcapsules containing amine curing agents and polyaniline to the base component epoxy resin (epoxy glue or epoxy powder) to obtain a microcapsule-type epoxy coating with dual functions of self-repairing and anti-corrosion.

[0011] Preferably, the static voltage is 13-22 kV.

[0012] Preferably, the particle size of the microcapsules containing epoxy resin monomers is 50 to 150 μm, and the particle size of the microcapsules containing amine curing agents and polyaniline is 50 to 150 μm.

[0013] Preferably, the microcapsules containing epoxy resin monomers and the microcapsules containing amine curing agents and polyaniline in step (3) account for 5-20% by mass of the total coating, more preferably 10-15%.

[0014] Preferably, the mass ratio of the amine curing agent to polyaniline in step (1) is 99.5:0.5 to 95:5, more preferably 99:1.

[0015] Preferably, the mass ratio of the microcapsules containing epoxy resin monomers to the microcapsules containing amine curing agents and polyaniline is 1:1.

[0016] Preferably, the low-grade solvent is a mixture of equal volumes of decalin and hexadecane; the surfactant is Arlacel P135; and the mass ratio of the low-grade solvent to the surfactant and HMDI is (100±20):1:(12±6).

[0017] Preferably, the core liquid of the microcapsules containing epoxy resin monomers is composed of bisphenol F diglycidyl ether (BFDGE) and diluent n-butyl glycidyl ether (BGE), and the capsule wall is composed of polyurea; the core liquid of the microcapsules containing amine curing agent and polyaniline is composed of tetraethylene pentamine (TEPA), polyether polyamine (JEFFAMINE T403) and polyaniline, and the capsule wall is composed of polyurea; the mass ratio of tetraethylene pentamine to polyether polyamine is (25±5):(75±5).

[0018] The microcapsule-based epoxy coating, which exhibits both self-healing and corrosion protection properties, prepared by the above method can be applied to the surfaces of metal components. Specifically, an epoxy adhesive is mixed with epoxy resin microcapsules and an amine curing agent / polyaniline microcapsules, applied to a substrate, and then cured. The coating has a thickness of 50-600 μm, preferably 300 μm.

[0019] The present invention creates a microcapsule-based epoxy coating that possesses both self-repairing and corrosion protection capabilities. Microcapsules containing epoxy resin and microcapsules containing both an amine curing agent and a polyaniline corrosion inhibitor are added to the base epoxy coating. When the epoxy coating formed by curing the coating becomes damaged, the epoxy resin released from the microcapsules polymerizes with the amine curing agent to repair the damaged area, while the polyaniline corrosion inhibitor released from the microcapsules restores the corrosion protection of the damaged area. This achieves both self-repair and corrosion protection for the coating and enhances its performance.

[0020] When polyaniline anticorrosive agent is not added, microcapsules containing 25TEPA75T403 amine curing agent can be prepared using T-junction microfluidics-interfacial polymerization microencapsulation technology. However, due to the higher viscosity of 25TEPA75T403 amine curing agent, its viscosity can sharply increase after adding polyaniline anticorrosive agent, making it difficult to prepare microcapsules containing amine curing agent / polyaniline anticorrosive agent. The present invention has adopted electrostatic spraying technology to prepare amine curing agent / polyaniline anticorrosive agent micro-droplets, and further uses interfacial polymerization technology to prepare microcapsules containing amine curing agent / polyaniline anticorrosive agent simultaneously. In addition, because polyaniline is also a kind of polyamine, it also can react with the shell monomer HMDI in the reaction solution in the microencapsulation process, affects microencapsulation process and prepared microcapsules on the one hand, also consumes the polyaniline anticorrosive agent in the microcapsule core liquid on the other hand, makes the content of polyaniline anticorrosive agent in the final microcapsule too low and cannot play effect. Therefore, the present invention adjusts the polarity of the reaction solution and the process parameters (temperature and time) during the microencapsulation process, thereby ultimately obtaining microcapsules containing an amine curing agent and a polyaniline anticorrosive agent with excellent comprehensive performance.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention forms a microcapsule-based epoxy coating that has both self-repairing and corrosion protection functions by adding high-performance two-component microcapsules, namely epoxy resin microcapsules and amine curing agent / polyaniline microcapsules, to a commercial epoxy resin. When the coating is damaged, the epoxy resin released from the microcapsules reacts with the amine curing agent to repair the damaged area through polymerization, while the polyaniline anticorrosive agent released from the microcapsules repairs the damaged area's corrosion protection, thereby achieving both self-repairing and corrosion protection functions and enhancing its performance.

[0023] (2) The anticorrosive agent polyaniline used in the present invention is compatible with the amine curing agent and its microencapsulation technology, and can be conveniently encapsulated using the existing electrostatic spray-interfacial polymerization microencapsulation technology to prepare simultaneous amine curing agent / polyaniline microcapsules.

[0024] (3) The present invention adopts an electrostatic spray-interfacial polymerization composite method to prepare epoxy resin microcapsules and amine curing agent / polyaniline microcapsules respectively. The obtained two microcapsules are powders with a particle size of 50 to 150 μm, which can be easily mixed and applied with existing commercial epoxy coatings.

[0025] (4) The microcapsule-based epoxy coating of the present invention, which has both self-repairing and anti-corrosion functions, makes full use of the characteristics of the microencapsulated repair agent and the microencapsulated anti-corrosion agent, combines the self-repairing function and the anti-corrosion function of the two, and forms an epoxy coating with enhanced anti-corrosion performance. Due to the discrete distribution of the microcapsules in the coating, when the repair agent released from the microcapsules fills the cracks, it is possible that part of the cracks are filled and part is not filled. Although the cracked part filled with the repair agent can bring self-repairing function to the coating, the unfilled part cannot prevent the corrosive medium from corroding the protected object. After adding polyaniline, an anti-corrosion agent, to the amine microcapsules, although the repair agent released from the microcapsules may only partially fill the cracks, the polyaniline will flow out of the microcapsules along with the amine curing agent and fill the cracks; in addition, when the corrosive medium penetrates the cracks, the polyaniline entrained in the repair agent slowly dissolves in water and slowly diffuses to the part of the crack that is not filled by the repair agent, thereby realizing the anti-corrosion function of the unfilled crack part. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a photo of the amine microcapsules containing 25TEPA75T403 and the microcapsules containing 25TEPA75T403 and 1% polyaniline, obtained in Example 1 of the present invention. The microcapsules containing 25TEPA75T403 are pure white solid powders, while the microcapsules containing 25TEPA75T403 and 1% polyaniline are light yellow-green solid powders.

[0027] Figure 2 Scanning electron microscope (SEM) images of microcapsules containing 25TEPA75T403 and 1% polyaniline prepared in Example 1 of the present invention, wherein: Figure (a) is a complete microcapsule, and Figure (b) is a cross-sectional view of the microcapsule after cutting.

[0028] Figure 3 The following are the appearances of different epoxy coatings applied to iron sheets after two days of accelerated corrosion in a 10.0 wt% saline solution: (a) pure epoxy coating without microcapsules; (b) self-healing epoxy coating containing epoxy microcapsules and amine microcapsules; (c) self-healing anti-corrosion epoxy coating with 1% polyaniline microcapsules added according to Example 1; (d) self-healing anti-corrosion epoxy coating with 5.0 wt% polyaniline microcapsules added according to Example 2. Each coating (a)-(d) has a thickness of approximately 300 μm, contains 5.0 wt% of both epoxy and amine / polyaniline microcapsules, and has a particle size of approximately 100 μm.

[0029] Figure 4 for Figure 3 c. The filling of cracks in the self-healing anti-corrosion epoxy coating by the repair agent.

[0030] Figure 5 Appearance of epoxy coating containing different concentrations of microcapsules after 2 days accelerated corrosion in 10.0 wt% salt water solution, where (a) is the total concentration of epoxy microcapsules and amine microcapsules containing polyaniline is 5.0 wt%; (b) is the total concentration of epoxy microcapsules and amine microcapsules containing polyaniline is 20.0 wt%. The coating thickness of both figures is about 300 μm, and the particle size of microcapsules is about 100 μm.

[0031] Figure 6 Appearance of epoxy coating containing different particle sizes of microcapsules after 2 days accelerated corrosion in 10.0 wt% salt water solution, where (a) is the particle size of epoxy microcapsules and amine microcapsules containing polyaniline is about 50 μm; (b) is the particle size of epoxy microcapsules and amine microcapsules containing polyaniline is about 150 μm. The coating thickness of both figures is about 300 μm, and the total concentration of microcapsules is about 10.0 wt%.

[0032] Figure 7 Appearance of self-healing epoxy coating with different thicknesses after 2 days accelerated corrosion in 10.0 wt% salt water solution, where (a) is the coating thickness is about 200 μm, and (b) is the coating thickness is about 600 μm. The particle size of microcapsules in the coating is about 100 μm, and the concentration of microcapsules is 10.0 wt%. DETAILED DESCRIPTION

[0033] The present application is further described in connection with the specific embodiments disclosed herein, by reference to the following figures of the drawings, but the application should not be construed as limited to the embodiments set forth in the figures, which are given by way of example. Any modification in the given figures, within the scope of the claims of the present application, is still within the scope of the present application.

[0034] Example 1

[0035] (1) 90 parts of bisphenol F diglycidyl ether (BFDGE) was mixed with 10 parts of active diluent n-butyl glycidyl ether (BGE) to form F10B epoxy resin. 95 parts of the epoxy solution was mixed with 5 parts of 4,4-dicyclohexyl methane diisocyanate (HMDI) to form the core solution to be encapsulated. 10 mL of the core solution was loaded into a syringe and extruded at a rate of 10.0 mL / h, and atomized under the electrostatic voltage of 17 kV to form the core microdroplets. The above core microdroplets were received by a reaction solution containing 100.0 mL of deionized water, 1.0 g of sodium dodecyl sulfonate, and 12.0 g of diethylenetriamine to form the nascent microcapsules containing epoxy resin. After the preparation of the nascent microcapsules, the mixture of the above nascent microcapsules and the reaction solution was reacted at 90°C for 9 h to form the final microcapsules containing epoxy resin. Finally, after washing with water, filtering, and drying at room temperature, the finished product epoxy resin microcapsules with a particle size of about 100 μm were obtained.

[0036] (2) 25 parts of tetraethylenepentamine (TEPA) and 75 parts of polyether polyamine (JEFFAMINE T403) were mixed uniformly to form a 25TEPA75T403 mixed amine curing agent; 99 parts of 25TEPA75T403 and 1 part of polyaniline were mixed uniformly in a 60°C water bath using an ultrasonic disperser (power 60W) for 60 minutes to form a core liquid to be coated; 10 mL of the core liquid was loaded into a syringe and extruded at a rate of 6.0 mL / h and atomized under an electrostatic voltage of 16 kV to form core liquid microdroplets. A reaction solution containing 50.0 mL of a low-grade solvent (decalin: hexadecane volume ratio of 1:1), 0.5 g of a surfactant Arlacel P135, and 6.0 g of HMDI was used to receive the core liquid microdroplets to form primary microcapsules containing the amine curing agent and polyaniline. After the primary microcapsules are prepared, the mixture containing the primary microcapsules and the reaction solution is reacted at 50°C for 6 hours to form the final microcapsules containing the amine curing agent and polyaniline. Finally, the mixture is washed with pure cyclohexane, filtered, dried at room temperature for 5-10 minutes, and then vacuum-dried at 60°C for 1 hour to obtain the finished microcapsules containing the amine curing agent and polyaniline.

[0037] (3) Clean the iron plate with acetone, remove the surface grease, and then polish it with 800-grit sandpaper. After cleaning with acetone, let it stand and dry at room temperature for use. Take 0.50g of epoxy resin microcapsules and 0.50g of amine curing agent / polyaniline microcapsules, premix them evenly, add them to 9.0g of epoxy resin glue (Epolam 5015: Hardener 5015=100:30), and mix them evenly. Use a coating instrument to evenly spread the above mixture on the prepared iron plate with a thickness of 300μm, first cure it at 25℃ for 24h, and then cure it at 35℃ for 24h, finally forming an epoxy coating with both self-repairing and anti-corrosion functions.

[0038] Figure 1 (b) shows the appearance of microcapsules containing both amine curing agent and polyaniline anticorrosive agent prepared using the parameters in (2). The microcapsules are yellow-green, dry and dispersed, and can flow freely like sand. Figure 2 (a) shows the SEM image of microcapsules containing both amine curing agent and polyaniline anticorrosive agent prepared using the parameters in (2). The size of the microcapsules is about 100 μm. Figure 2 (b) shows the cross section of the microcapsule after it is cut open, and the microcapsule wall is thin and dense.

[0039] Comparative Example 1 Pure Epoxy Coating

[0040] The iron plate was cleaned with acetone to remove surface grease, then polished with 800-grit sandpaper. After rinsing with acetone, it was allowed to dry at room temperature. Using a film applicator, pure epoxy resin (Epolam 5015:Hardener 5015 = 100:30) was evenly spread onto the prepared iron plate to a thickness of 300 μm. The coating was then cured at room temperature for 24 hours, followed by a 24-hour cure at 35°C, to form a pure epoxy anti-corrosion coating.

[0041] Comparative Example 2

[0042] Different from Example 1, the microcapsules used to prepare the self-repairing anti-corrosion coating are epoxy resin microcapsules and microcapsules containing only amine curing agents.

[0043] Figure 1 (a) shows the appearance of the prepared microcapsules containing amine curing agents. The microcapsules are white, dry and dispersed, and can flow freely like sand.

[0044] Test Example 1 Accelerated corrosion test on iron plate samples coated with epoxy coating

[0045] A crack was created on an iron plate by impact damage in a pure epoxy coating (reference sample, comparative example 1), a self-repairing coating (self-repairing sample, comparative example 2), or an epoxy coating having both self-repairing and anti-corrosion functions (dual-function sample, example 1). The sample was then left to repair at room temperature for 2 days and then immersed in a 10.0 wt% saline solution to accelerate corrosion. The corrosion behavior of the sample was observed.

[0046] Since polyaniline is also a polyamine, it can react with epoxy monomers when released from the microcapsules and comes into contact with them. However, because its amine group activity is much lower than that of other amine curing agents (TEPA and T403) in the microcapsules, the polyaniline released from the microcapsules can be retained during the polymerization reaction between the epoxy monomer and TEPA / T403. After the epoxy monomer and TEPA / T403 cure and fill the damaged areas of the coating, it can still slowly diffuse out of the cured repair agent to the damaged areas of the coating that have not been filled and repaired by the repair agent, thus providing corrosion protection for the unfilled areas.

[0047] Figure 3(a)-(c) are the appearances of the reference sample in Comparative Example 1, the self-repairing sample using microcapsules containing only amine curing agents in Comparative Example 2, and the dual-functional sample with both self-repairing and corrosion protection using microcapsules containing both amine curing agents and polyaniline in Example 1, respectively, after two days of accelerated corrosion in salt water. The comparison shows that the reference sample without microcapsules exhibited severe corrosion at the cracks; the reference sample using microcapsules containing only amine curing agents had some corrosion resistance, but still exhibited some corrosion in certain areas of the cracks; and the dual-functional sample using microcapsules containing both amine curing agents and polyaniline exhibited virtually no corrosion, demonstrating excellent self-repair and corrosion resistance. Figure 4 for Figure 3 Figure c shows the filling of cracks with repairing agent in the self-healing epoxy coating. As can be seen from the figure, if only epoxy resin microcapsules and amine curing agent microcapsules are used, although the repairing agent flowing out of the microcapsules can fill and repair most areas of the cracks, there are still areas in the cracks that are not filled with the repairing agent. Although the filled parts of the cracks can prevent the corrosive medium from contacting the iron plate, thereby preventing corrosion, the unfilled parts of the cracks will lose their anti-corrosion properties. When the microcapsules contain polyaniline anti-corrosion agent, although there are still cracks that are not filled and repaired by the repairing agent, the polyaniline released by the microcapsules can diffuse to the crack areas that are not filled with the repairing agent, realizing the anti-corrosion function of the unfilled crack areas.

[0048] Example 2

[0049] The difference from Example 1 is that 95 parts of 25TEPA75T403 and 5 parts of polyaniline are evenly mixed to form a core liquid to be coated, microcapsules with a higher polyaniline content are prepared, and an epoxy coating with both self-repairing and anti-corrosion functions is further prepared.

[0050] Figure 3 (d) shows the appearance of an epoxy coating sample with both self-repairing and anti-corrosion functions prepared by using microcapsules containing 95.0wt% amine curing agent and 5.0wt% polyaniline after accelerated corrosion in salt water for 2 days. Figure 3 (c) An epoxy coating having both self-repairing and anti-corrosion dual functions using microcapsules containing 1.0 wt% polyaniline has better anti-corrosion performance.

[0051] Example 3

[0052] The difference from Example 1 is that the masses of the epoxy resin microcapsules, amine curing agent / polyaniline microcapsules, and epoxy glue used in preparing the epoxy coating with both self-repairing and anti-corrosion dual functions are 0.25g:0.25g:9.5g and 1.0g:1.0g:8.0g, respectively, forming an epoxy coating with both self-repairing and anti-corrosion dual functions with a total microcapsule concentration of 5.0wt% and 20.0wt%, respectively.

[0053] Figure 5 The images show the appearance of epoxy coating samples containing different concentrations of microcapsules, which possess both self-healing and anti-corrosion properties, after two days of accelerated corrosion in salt water. When the microcapsule concentration is low, the coating's anti-corrosion performance decreases, while when the microcapsule concentration is high, the coating's anti-corrosion performance increases.

[0054] Example 4

[0055] The difference from Example 1 is that the electrostatic voltages for preparing the amine curing agent / polyaniline microcapsules in step (2) are 13 kV and 22 kV, respectively, and the particle sizes of the prepared amine curing agent / polyaniline microcapsules are approximately 150 μm and 50 μm, respectively. Amine curing agent / polyaniline microcapsules with this particle size are used to prepare epoxy coatings having both self-repairing and anti-corrosion dual functions.

[0056] Figure 6 Images show the appearance of epoxy coating samples containing microcapsules of varying particle sizes, which exhibit both self-healing and anti-corrosion properties, after two days of accelerated corrosion in salt water. Smaller microcapsule sizes reduce the coating's self-healing and anti-corrosion properties, while larger microcapsule sizes enhance these properties.

[0057] Example 5

[0058] The difference from Example 1 is that the thickness of the epoxy coating in this embodiment is 200 μm and 600 μm respectively.

[0059] Figure 7 Images show the appearance of epoxy coating samples with different coating thicknesses, which exhibit both self-healing and corrosion protection properties, after two days of accelerated corrosion in salt water. When the coating thickness is low, the self-healing and corrosion protection properties of the coating decrease; however, when the coating thickness is high, the self-healing and corrosion protection properties of the coating increase.

[0060] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a microcapsule-type epoxy coating having dual functions of self-repair and anti-corrosion, characterized in that: The steps include: (1) Ultrasonic dispersion of the amine curing agent and polyaniline in a water bath at 60±20°C for 60±20 min to form a core liquid to be coated; atomizing the core liquid under an electrostatic voltage of 10-25 kV to form core liquid microdroplets; (2) using a reaction solution containing a low-grade solvent, a surfactant, and HMDI to receive the core liquid microdroplets to form primary microcapsules; reacting the mixture of the primary microcapsules and the reaction solution at 50±10°C for 6±2h, washing, filtering, and drying to obtain microcapsules containing an amine curing agent and polyaniline; (3) Adding microcapsules containing epoxy resin monomers and microcapsules containing amine curing agents and polyaniline to the base component epoxy resin, a microcapsule-type epoxy coating with dual functions of self-repairing and anti-corrosion is obtained; The low-grade solvent is a mixture of equal volumes of decalin and hexadecane; The core liquid of the microcapsules containing epoxy resin monomers is composed of bisphenol F diglycidyl ether and a diluent, and the capsule wall is composed of polyurea. The core liquid of the microcapsules containing amine curing agents and polyaniline is composed of tetraethylene pentamine, polyether polyamine and polyaniline, and the capsule wall is composed of polyurea. The mass ratio of tetraethylene pentamine to polyether polyamine is (25±5):(75±5), and the mass ratio of the amine curing agent to polyaniline is 99.5:0.5~95:

5.

2. The preparation method according to claim 1, wherein The static voltage is 13-22 kV.

3. The preparation method according to claim 2, characterized in that: The particle size of the microcapsules containing epoxy resin monomers is 50-150 μm, and the particle size of the microcapsules containing amine curing agents and polyaniline is 50-150 μm.

4. The preparation method according to claim 3, wherein The microcapsules containing epoxy resin monomers and the microcapsules containing amine curing agents and polyaniline in step (3) account for 5-20% of the total mass percentage of the coating.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the amine curing agent to polyaniline in step (1) is 99:

1.

6. The preparation method according to claim 5, characterized in that: The mass ratio of the microcapsules containing epoxy resin monomers to the microcapsules containing amine curing agents and polyaniline is 1:

1.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The surfactant is Arlacel P135; the mass ratio of the low-grade solvent to the surfactant and HMDI is (100±20):1:(12±6).

8. The preparation method according to claim 7, characterized in that: The microcapsules containing epoxy resin monomers and the microcapsules containing amine curing agents and polyaniline account for 10-15% of the total mass percentage of the coating.

9. A microcapsule-type epoxy coating having dual functions of self-repairing and anti-corrosion, prepared by the method according to any one of claims 1 to 8.

10. The use of the microcapsule epoxy coating with dual functions of self-repair and anti-corrosion according to claim 9, characterized in that: The coating is used on the surface of a metal device, and the thickness of the coating is 50-600 μm.

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