Microcapsule type epoxy coating with double functions of self-repairing and corrosion prevention as well as preparation method and application of microcapsule type epoxy coating

Abstract

The invention discloses a microcapsule type epoxy coating with self-repairing and anti-corrosion dual functions and a preparation method and application thereof.The preparation method comprises the steps that an amine curing agent and polyaniline are subjected to ultrasonic dispersion under specific conditions, and core liquid to be wrapped is formed; the core liquid is atomized under the electrostatic voltage of 10-25 kV, and core liquid micro-droplets are formed; receiving the core liquid micro-droplets by using a reaction solution containing a low-grade solvent, a surfactant and HMDI (hexamethylenediphenyl diisocyanate) to form a primary microcapsule; reacting the mixture containing the primary microcapsule and the reaction solution to obtain a microcapsule containing the amine curing agent and polyaniline; a microcapsule containing an epoxy resin monomer and a microcapsule containing an amine curing agent and polyaniline are added into epoxy resin, and the microcapsule type epoxy coating with self-repairing and anti-corrosion dual functions is obtained. According to the invention, the two-component microcapsule with excellent performance is added into commercialized epoxy resin, so that the microcapsule-based epoxy coating with double functions of self-repairing and corrosion resistance is formed.

Description

Technical Field

[0001] The 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 fields of petrochemicals, marine engineering and construction. Traditional anti-corrosion coatings mostly use epoxy resins, which have excellent adhesion, chemical stability and mechanical strength, making them a widely used protective material. However, during the use of epoxy coatings, they still face problems such as scratches, cracks and peeling, which greatly reduces the protective effect of the coating and causes corrosion and damage to the substrate.

[0003] To solve this problem, researchers began to explore self-healing coating technology. The principle of self-healing coating is to automatically repair coating damage caused by external factors through the self-healing ability of internal materials, thereby extending the service life of the coating. In recent years, the application of microcapsule technology has provided new ideas for the research of self-healing coatings. Microcapsules can encapsulate repair agents. When the coating is damaged, the microcapsules rupture and release the repair agents, thereby achieving self-repair. However, relying solely on this self-healing mechanism often cannot fully meet the anti-corrosion needs.

[0004] Chinese patent 201910649137.2 discloses a method for preparing a self-repairing and anti-corrosion coating, and the preparation method steps are as follows: step 1, prepare an oil-in-water O / W type emulsion containing a repair agent, and form a microcapsule shell by radiation crosslinking or thermal crosslinking; step 2, drop aniline into the dispersion of the microcapsule shell obtained in step 1, add an aqueous solution containing an aniline initiator, and obtain polyaniline microcapsules after reaction; step 3, mix the polyaniline microcapsules with a matrix resin to obtain the self-repairing and anti-corrosion coating. That is, the aniline is fixed to the surface of the emulsion droplets through the strong electrostatic interaction between the aniline monomer and the emulsifier molecules, so that the aniline is polymerized and doped on the surface of the emulsion droplets, and a layer of polyaniline microcapsule shell is prepared, and the core is loaded with a repair agent. The disadvantage is that the polyaniline with anti-corrosion function is located in the capsule material, and the polyaniline in the capsule material is grown in situ and is wrapped in the matrix coating. When the crack is formed, it is difficult to diffuse into the crack, so it is difficult to achieve a better anti-corrosion effect. Summary of the invention

[0005] One of the purposes of the present invention is to provide an epoxy coating based on microcapsules that has both self-repairing and anti-corrosion functions. A coating that has both self-repairing and anti-corrosion functions is formed by compounding microcapsules containing epoxy monomers with microcapsules containing both amine curing agents and polyaniline. This technology can not only realize the self-repairing function of the coating, but also significantly improve the anti-corrosion performance of the coating, and at the same time greatly simplify the curing and molding conditions.

[0006] The technical solution of the present invention is as follows:

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

[0008] (1) ultrasonically dispersing the amine curing agent and polyaniline in a water bath at 60±20° C. for 60±20 min to make them uniform, thereby forming a core liquid to be coated; atomizing the core liquid at 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 total mass percentage of the microcapsules containing epoxy resin monomers and the microcapsules containing amine curing agents and polyaniline in step (3) is 5-20%, 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 decalin and hexadecane in equal volumes; 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 microcapsule containing epoxy resin monomer 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 microcapsule 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 and polyether polyamine is (25±5):(75±5).

[0018] The microcapsule-type epoxy coating with dual functions of self-repair and corrosion protection prepared by the above method can be used on the surface of metal devices. Specifically, the epoxy glue, epoxy resin microcapsules and amine curing agent / polyaniline microcapsules are mixed, coated on the substrate, and then cured. The thickness of the coating is 50-600 μm, preferably 300 μm.

[0019] The present invention is an epoxy coating with dual functions of self-repair and corrosion protection based on microcapsules. Microcapsules containing epoxy resin and microcapsules containing both amine curing agent and polyaniline corrosion inhibitor are added to the epoxy coating as a basic component. After the epoxy coating formed by curing of the coating is damaged, the epoxy resin released from the microcapsules and the amine curing agent undergo polymerization reaction to repair the damaged part, and the polyaniline corrosion inhibitor released from the microcapsules can repair the corrosion protection function of the damaged part, thereby realizing the dual functions of self-repair and corrosion protection of the coating damage and enhancing 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 high viscosity of 25TEPA75T403 amine curing agent, its viscosity will increase dramatically after adding polyaniline anticorrosive agent, making it difficult to prepare microcapsules containing amine curing agent / polyaniline anticorrosive agent. The present invention adopts electrostatic spraying technology to prepare amine curing agent / polyaniline anticorrosive agent microdroplets, and further uses interfacial polymerization technology to prepare microcapsules containing amine curing agent / polyaniline anticorrosive agent simultaneously. In addition, since polyaniline is also a polyamine, it will also react with the shell monomer HMDI in the reaction solution during the microencapsulation process, affecting the microencapsulation process and the prepared microcapsules on the one hand, and also consuming the polyaniline anticorrosive agent in the microcapsule core liquid on the other hand, so that the content of polyaniline anticorrosive agent in the final microcapsule is too low and cannot play a role. Therefore, the present invention adjusts the polarity of the reaction solution and the process parameters (temperature and time) in the microencapsulation process, and finally obtains 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 an epoxy coating based on microcapsules with dual functions of self-repair and corrosion resistance by adding two-component microcapsules with excellent performance, namely epoxy resin microcapsules and amine curing agent / polyaniline microcapsules, to commercial epoxy resin. After the coating is damaged, the epoxy resin released from the microcapsules and the amine curing agent undergo polymerization reaction to repair the damaged part, while the polyaniline anticorrosive agent released from the microcapsules can repair the anticorrosion function of the damaged part, thereby achieving the dual functions of self-repair and corrosion resistance of the coating damage and enhancing its performance.

[0023] (2) The anticorrosive 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 constructed with existing commercial epoxy coatings.

[0025] (4) The microcapsule-based epoxy coating with dual functions of self-repair and corrosion protection described in the present invention makes full use of the characteristics of microencapsulated repair agents and microencapsulated anticorrosive agents, combining the self-repair function and the anticorrosion function of the two to form an epoxy coating with enhanced anticorrosion performance. Due to the discrete distribution of 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 crack part filled with the repair agent can bring self-repair function to the coating, the unfilled part cannot prevent the corrosive medium from corroding the protected object. After adding polyaniline, an anticorrosive agent, to amine microcapsules, although the repair agent released from the microcapsules may only partially fill the cracks, the polyaniline will flow out of the microcapsules with the amine curing agent and fill the cracks; in addition, when the corrosive medium penetrates into the cracks, the polyaniline mixed 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 anticorrosion function of the unfilled crack part. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The actual picture shows the amine microcapsules containing 25TEPA75T403 and the microcapsules containing 25TEPA75T403 and 1% polyaniline prepared in Example 1 of the present invention, wherein the microcapsules containing 25TEPA75T403 are pure white solid powder, while the microcapsules containing 25TEPA75T403 and 1% polyaniline are light yellow-green solid powder.

[0027] Figure 2 The scanning electron microscope (SEM) images of the 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 appearance of different epoxy coatings coated on iron sheets after accelerated corrosion in 10.0wt% saline solution for 2 days: (a) pure epoxy coating without microcapsules; (b) self-repairing epoxy coating containing epoxy microcapsules and amine microcapsules; (c) self-repairing anti-corrosion epoxy coating with 1% polyaniline microcapsules added in Example 1; (d) self-repairing anti-corrosion epoxy coating with 5.0wt% polyaniline microcapsules added in Example 2. The thickness of each coating (a)-(d) is about 300μm, the content of epoxy microcapsules and amine / polyaniline microcapsules in the coating is 5.0wt%, and the particle size of epoxy microcapsules and amine / polyaniline microcapsules is about 100μm.

[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 The appearance of epoxy coatings containing microcapsules of different concentrations after accelerated corrosion in 10.0wt% saline solution for 2 days, where (a) is the total concentration of epoxy microcapsules and amine microcapsules containing polyaniline at 5.0wt%; (b) is the total concentration of epoxy microcapsules and amine microcapsules containing polyaniline at 20.0wt%. The coating thickness of both figures is about 300μm, and the microcapsule particle size is about 100μm.

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

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

[0033] The present invention will be further described below in conjunction with the specific embodiments in the accompanying drawings, but this does not constitute any limitation to the present invention. Any limited modifications made within the scope of protection of the claims of the present invention are still within the scope of protection of the claims of the present invention.

[0034] Example 1

[0035] (1) 90 parts of bisphenol F diglycidyl ether (BFDGE) and 10 parts of active diluent n-butyl glycidyl ether (BGE) were mixed evenly to form F10B epoxy resin. 95 parts of the epoxy solution were mixed evenly with 5 parts of 4,4-dicyclohexylmethane diisocyanate (HMDI) 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 10.0 mL / h, and atomized under an electrostatic voltage of 17 kV to form core liquid microdroplets. A reaction solution containing 100.0 mL of deionized water, 1.0 g of sodium dodecyl sulfate, and 12.0 g of diethylenetriamine was used to receive the core liquid microdroplets to form primary microcapsules containing epoxy resin. After the primary microcapsules were prepared, the mixture containing the primary microcapsules and the reaction solution was reacted at 90°C for 9 hours to form final microcapsules containing epoxy resin. Finally, after washing with water, filtering and drying at room temperature, finished epoxy resin microcapsules with a particle size of about 100 μm are obtained.

[0036] (2) 25 parts of tetraethylenepentamine (TEPA) and 75 parts of polyether polyamine (JEFFAMINE T403) were mixed evenly to form a 25TEPA75T403 mixed amine curing agent; 99 parts of 25TEPA75T403 and 1 part of polyaniline were mixed in a 60°C water bath for 60 minutes using an ultrasonic disperser (power 60W) to make them uniform, forming a core liquid to be wrapped; 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 an 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 final microcapsules containing amine curing agent and polyaniline. Finally, the final microcapsules are washed and filtered with pure cyclohexane, dried at room temperature for 5-10 minutes, and then vacuum dried at 60°C for 1 hour to obtain finished microcapsules containing 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, then cure it at 35℃ for 24h, and finally form 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), and 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, and after removing the surface grease, it was polished with 800-grit sandpaper. After cleaning with acetone, it was left to dry at room temperature for use. Pure epoxy resin (Epolam 5015: Hardener 5015 = 100: 30) was evenly spread on the prepared iron plate with a thickness of 300 μm using a coating apparatus, and then cured at room temperature for 24 hours, and then cured at 35°C for 24 hours, to finally 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 agent. The microcapsules are white, dry and dispersed, and can flow freely like sand.

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

[0045] A crack was created 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) on an iron plate by impact damage. 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, and the corrosion behavior of the sample was observed.

[0046] Since polyaniline is also a polyamine, it can also react with epoxy monomer when it comes into contact with epoxy monomer after being released from the microcapsule. However, since its amine activity is very low compared to other amine curing agents (TEPA and T403) in the microcapsule, the polyaniline released from the microcapsule can be retained when the epoxy monomer and TEPA / T403 undergo polymerization reaction. After the epoxy monomer and TEPA / T403 are cured and fill the damaged part of the coating, it can still slowly diffuse out from the cured repair agent to the damaged part of the coating that has not been filled and repaired by the repair agent, thereby realizing the anti-corrosion function of the unfilled part.

[0047] Figure 3(a)-(c) are the appearance pictures of the reference sample of comparative example 1, the self-repairing sample using microcapsules containing only amine curing agents in comparative example 2, and the dual-functional sample having both self-repairing and anti-corrosion functions using microcapsules containing both amine curing agents and polyaniline in Example 1 after accelerated corrosion in salt water for 2 days. By comparison, it can be seen that the reference sample without microcapsules is severely corroded at the cracks; the reference sample using microcapsules containing only amine curing agents has a certain anti-corrosion ability, but still has a certain degree of corrosion behavior in some parts of the cracks; the dual-functional sample using microcapsules containing both amine curing agents and polyaniline has basically no corrosion behavior, showing good dual self-repairing and anti-corrosion capabilities. Figure 4 for Figure 3 Figure 3. The filling of cracks in the self-healing epoxy coating of c. As can be seen from the figure, if only epoxy resin microcapsules and amine curing agent microcapsules are used, although the repair agent flowing out of the microcapsules can fill and repair most of the cracks, there are still areas in the cracks that are not filled with the repair agent. Although the filled part of the crack can prevent the corrosive medium from contacting the iron plate, thereby preventing corrosion, the unfilled part of the crack will lose its anti-corrosion performance. When the microcapsules contain polyaniline anti-corrosion agent, although there are still cracks that are not filled and repaired by the repair agent, the polyaniline released by the microcapsules can diffuse to the crack area that is not filled with the repair agent, thereby realizing the anti-corrosion function of the unfilled crack area.

[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 dual functions of self-repairing and anti-corrosion 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) The epoxy coating having both self-repairing and anti-corrosion 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 in which the total microcapsule concentration is 5.0wt% and 20.0wt%, respectively.

[0053] Figure 5 The appearance of epoxy coating samples with self-repair and anti-corrosion functions containing different concentrations of microcapsules after accelerated corrosion in salt water for 2 days is shown. When the concentration of microcapsules is low, the anti-corrosion performance of the coating decreases; when the concentration of microcapsules is high, the anti-corrosion performance of the coating increases.

[0054] Example 4

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

[0056] Figure 6 The appearance of epoxy coating samples containing microcapsules of different particle sizes and having both self-repair and anti-corrosion functions after 2 days of accelerated corrosion in salt water is shown. When the microcapsule particle size is smaller, the self-repair and anti-corrosion properties of the coating decrease; while when the microcapsule particle size is larger, the self-repair and anti-corrosion properties of the coating increase.

[0057] Example 5

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

[0059] Figure 7 The appearance of epoxy coating samples with different coating thicknesses and dual functions of self-repair and corrosion protection after 2 days of accelerated corrosion in salt water is shown. When the coating thickness is small, the self-repair and corrosion protection performance of the coating decreases; when the coating thickness is large, the self-repair and corrosion protection 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 equivalent replacement methods and are included in the protection scope 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) ultrasonically dispersing the amine curing agent and polyaniline in a water bath at 60±20° C. for 60±20 min to make them uniform, thereby forming a core liquid to be coated; atomizing the core liquid at 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 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; (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 having the dual functions of self-repairing and anti-corrosion is obtained.

2. The preparation method according to claim 1, characterized in that: 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 to 150 μm, and the particle size of the microcapsules containing amine curing agents and polyaniline is 50 to 150 μm.

4. The preparation method according to claim 3, characterized in that: In step (3), the microcapsules containing epoxy resin monomers and the microcapsules containing amine curing agents and polyaniline 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 99.5:0.5 to 95:

5.

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 low-grade solvent is a mixture of decalin and hexadecane in equal volumes; 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 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 amine curing agents to polyaniline is 99:1; the total mass percentage of the microcapsules containing epoxy resin monomers and the microcapsules containing amine curing agents and polyaniline in the coating is 10-15%.

9. A microcapsule-type epoxy coating having dual functions of self-repairing and anti-corrosion, obtained 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-repairing and anti-corrosion according to claim 9, characterized in that: The coating is used on the surface of metal devices, and the thickness of the coating is 50-600 μm.

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