Rare earth modified antibacterial coating and preparation method thereof

Abstract

The application relates to the technical field of coatings, in particular to a rare earth modified antibacterial coating and a preparation method thereof, which comprises component A and component B; the component A is a main agent; the component B is a curing agent; the component A comprises the following components in weight fractions: 100-110 parts of a rare earth modified resin, 15-25 parts of a repairing agent loading unit and 3-5 parts of tetraethoxysilane; hydrogen sulfide gas in the environment penetrates into the crack interior and reacts with cerium ions in the rare earth modified resin through oxidation and reduction, a local acidic environment is formed in the crack area, the hydrolysis and rupture of a silicon-nitrogen bond are catalyzed, the repairing agent is released, dibutyltin dilaurate promotes the formation of new silicon-oxygen bonds by the hydrolysis of tetraethoxysilane and a large number of silanol groups generated by the hydrolysis of the silicon-nitrogen bond, and a crosslinking network is reconstructed; crack self-repairing triggered by hydrogen sulfide and without external intervention is realized.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically a rare earth modified antibacterial coating and its preparation method. Background Technology

[0002] In industries such as petrochemicals, wastewater treatment, and food fermentation, the inner wall coatings of pipelines are constantly exposed to a corrosive environment containing high humidity and hydrogen sulfide gas. Existing technology, such as the method for inhibiting microbial corrosion of metal pipelines disclosed in patent publication number CN110345338A, utilizes silicon nitride and cerium oxide to synthesize a dense rare-earth hybrid nano-silicon nitride sheet material, which is then mixed with graphene and surface functionalized. This material is then added to epoxy resin to prepare an anti-corrosion coating, which is applied to the surface of the metal pipeline. The nanoparticles in the material can directly catalyze the degradation of hydrogen sulfide gas produced by metabolism, further preventing hydrogen evolution corrosion. However, this coating can only prevent corrosion and does not address post-corrosion repair. As the concentration of hydrogen sulfide increases, localized corrosion is inevitable, but repairing corroded areas is very difficult in a hydrogen sulfide environment. Summary of the Invention

[0003] (1) Technical problems to be solved

[0004] The purpose of this invention is to provide a rare earth modified antibacterial coating and its preparation method, which utilizes hydrogen sulfide for self-repair in a corrosive environment containing hydrogen sulfide.

[0005] (2) Technical solution

[0006] To achieve the above objectives, on the one hand, the present invention provides a rare earth modified antibacterial coating, comprising component A and component B; wherein component A is the main agent; and component B is the curing agent;

[0007] Component A comprises the following components in parts by weight: 100-110 parts rare earth modified resin, 15-25 parts repair agent loading unit, and 3-5 parts tetraethoxysilane; wherein the rare earth modified resin and the repair agent loading unit are connected by silicon-nitrogen bonds.

[0008] Furthermore, component A further includes the following components in parts by weight: 20-30 parts rutile titanium dioxide, 5-10 parts mica powder, 0.5-1.5 parts dispersant, 0.2-0.5 parts leveling agent, 0.3-0.8 parts defoamer, and 30-50 parts mixed solvent.

[0009] Further, component B comprises the following components in parts by weight: 0.06 to 0.10 parts dibutyltin dilaurate, 40 to 42 parts polyamide 650 curing agent, and 10 to 12 parts anhydrous ethanol.

[0010] Furthermore, the dispersant is BYK-2155; the leveling agent is BYK-331; and the defoamer is BYK-066N.

[0011] Furthermore, the mixed solvent includes propylene glycol methyl ether acetate and xylene, wherein the mass ratio of propylene glycol methyl ether acetate to xylene is 1~3:1.

[0012] Furthermore, the preparation method of the rare earth modified resin includes the following steps:

[0013] S11. Add epoxy resin to tetrahydrofuran, stir, and heat to completely dissolve it to obtain an epoxy resin solution; dissolve diethylenetriamine in tetrahydrofuran and slowly add it dropwise to the epoxy resin solution, heat to react, after the reaction is complete, pour it into a large amount of ethanol to precipitate, filter, wash the precipitate with ethanol, and dry under vacuum to obtain the first compound.

[0014] S12. The first compound was dispersed in anhydrous N,N-dimethylformamide, and ethylenediaminetetraacetic acid dianhydride was added. The mixture was stirred and reacted under nitrogen protection. After the reaction was completed, the mixture was filtered, washed alternately with N,N-dimethylformamide and deionized water, and dried under vacuum to obtain the second compound.

[0015] S13. The second compound was added to deionized water and stirred vigorously to allow it to swell fully, resulting in a dispersion. Under rapid stirring, a 0.5 mol / L cerium ammonium nitrate solution was slowly added dropwise to the dispersion. After the addition was complete, the temperature was raised to allow the reaction to proceed. After the reaction was complete, the solid product was collected by centrifugation and washed repeatedly with deionized water until the supernatant was colorless. The product was then vacuum dried to constant weight to obtain the rare earth modified resin.

[0016] Furthermore, the preparation method of the repair agent loading unit includes the following steps:

[0017] S21. Under ice-water bath and high-speed shearing, epoxy resin is added to a 4wt% polyvinyl alcohol aqueous solution and emulsified to obtain an epoxy emulsion, which is then placed in an ice-water bath for later use.

[0018] S22. Melt m-phenylenediamine in a hot water bath, add anhydrous ethanol, and stir until completely dissolved to obtain an MPDA / ethanol solution; under ice-water bath and high-speed shearing, rapidly add the hot MPDA / ethanol solution dropwise to a 4wt% polyvinyl alcohol aqueous solution, and continue high-speed shearing to obtain an amine emulsion;

[0019] S23. Under low-speed mechanical stirring and ice-water bath conditions, the amine emulsion is slowly added dropwise to the epoxy emulsion, and then re-emulsified to obtain a re-emulsion;

[0020] S24. Immediately transfer the double emulsion to a three-necked flask, heat in a water bath, stir at low speed, add urea and ammonium chloride, and after they dissolve, slowly add 37% formaldehyde solution to adjust the pH to 3.5-4.0. After the reaction is complete, filter under vacuum, wash with water and ethanol to obtain the third compound.

[0021] S25. The third compound was dispersed in an ethanol / water mixture, the pH was adjusted to 5.0, 3-aminopropyltriethoxysilane was added, and after the reaction was completed, the mixture was filtered, washed thoroughly with ethanol, and dried to obtain the repair agent loading unit.

[0022] Furthermore, the volume ratio of ethanol to water in the ethanol / water mixed solution is 9:1.

[0023] Based on the same inventive concept, in a second aspect, the present invention also provides a method for preparing a rare earth-modified antibacterial coating, applicable to the preparation of the aforementioned rare earth-modified antibacterial coating, the preparation method comprising:

[0024] S31. Preparation of component A: In the mixing tank, add mixed solvent, dispersant, leveling agent and defoamer, stir at low speed until mixed evenly, then slowly add rutile titanium dioxide and mica powder while stirring. After the addition is complete, increase the speed and disperse at high speed. Slowly add rare earth modified resin and stir until it is completely dissolved. Then slowly add repair agent loading unit and tetraethoxysilane. After stirring, filter to obtain component A, and package it into barrels.

[0025] S32. Preparation of component B: In another mixing tank, add anhydrous ethanol, add dibutyltin dilaurate until completely dissolved while stirring, add polyamide 650 curing agent, stir at low speed to mix evenly, filter to obtain component B, and package into small barrels;

[0026] S33. When using, mix component A and component B at a mass ratio of 5:1, stir thoroughly, and then allow to mature to obtain a rare earth modified antibacterial coating.

[0027] Under normal conditions, the coating remains stable. When microcracks develop in the coating, hydrogen sulfide gas from the environment permeates into the cracks. At this point, cerium ions in the rare-earth modified resin act as a catalyst, reacting with the infiltrated hydrogen sulfide molecules in a redox reaction, creating a localized acidic environment in the crack area. The amino groups of the rare-earth modified resin form silicon-nitrogen bonds with the silanol groups of the repair agent loading unit, linking the two substances together. This acidic condition catalyzes the hydrolytic breakage of the silicon-nitrogen bonds. The breakage of these bonds allows the epoxy resin and m-phenylenediamine encapsulated within the repair agent loading unit to be released and flow out. The outflowing epoxy resin rapidly fills the crack voids, and its epoxy groups undergo in-situ polymerization and cross-linking reactions with the amino groups in m-phenylenediamine, forming a robust polymer network. This achieves efficient and precise self-sealing and repair of the cracks, with the entire process triggered by hydrogen sulfide and requiring no external intervention.

[0028] The silanol groups generated after the hydrolysis and breakage of silicon-nitrogen bonds can condense with other silanol groups to form silicon-oxygen bonds, thereby repairing the chemical bonds broken by hydrolysis and restoring the integrity and protective properties of the coating. If the generated small silanol molecules fail to re-crosslink in time, they may migrate or even volatilize inside the coating, leaving microscopic defects and becoming weak points in the coating performance. When hydrogen sulfide gas permeates into the crack and reacts with cerium ions to produce an acidic environment, this acidic condition also activates tetraethoxysilane. The four ethoxy groups in the tetraethoxysilane molecule rapidly hydrolyze under the acidic environment and trace amounts of moisture, generating a large number of highly reactive silanol groups. At the same time, the tin atoms in the dibutyltin dilaurate molecule can efficiently attract and activate multiple silanol groups (including those generated by tetraethoxysilane and those generated by the breakage of silicon-nitrogen bonds). Under its catalysis, these dispersed silanol groups no longer just slowly combine on their own, but are rapidly guided and interconnected, forming new silicon-oxygen bonds and reconstructing a dense three-dimensional crosslinked network. This process not only successfully consumed small-molecule silanol byproducts that could harm the stability of the coating, but also actively repaired and reinforced the coating network structure damaged by hydrolysis.

[0029] (3) Beneficial effects

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. This invention utilizes hydrogen sulfide gas from the environment to penetrate into the crack and react with cerium ions in the rare earth modified resin to form a local acidic environment in the crack area. This environment catalyzes the hydrolytic breakage of the silicon-nitrogen bonds connecting the rare earth modified resin and the repair agent loading unit. The breakage of these bonds allows the repair agent encapsulated inside the repair agent loading unit to be released, achieving self-sealing and repair of the crack. The entire process is triggered by hydrogen sulfide and requires no external intervention.

[0032] 2. This invention utilizes dibutyltin dilaurate to efficiently attract and activate tetraethoxysilane and a large number of silanol groups generated by the hydrolysis of silicon-nitrogen bonds. Under its catalysis, these dispersed silanol groups no longer simply combine slowly on their own, but are rapidly guided and interconnected, forming new silicon-oxygen bonds to reconstruct a dense three-dimensional cross-linked network. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the preparation process of a rare earth-modified antibacterial coating. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0035] Example 1: This example discloses a rare earth modified antibacterial coating, comprising component A and component B; component A is the main agent; component B is the curing agent;

[0036] Component A comprises the following components in parts by weight: 100 parts rare earth modified resin, 20 parts repair agent loading unit, and 4 parts tetraethoxysilane; wherein the rare earth modified resin and the repair agent loading unit are connected by silicon-nitrogen bonds.

[0037] Component A further comprises the following components in parts by weight: 25 parts rutile titanium dioxide, 8 parts mica powder, 1.0 part dispersant, 0.3 parts leveling agent, 0.5 parts defoamer, and 40 parts mixed solvent.

[0038] Component B comprises the following components in parts by weight: 0.08 parts dibutyltin dilaurate, 40 parts polyamide 650 curing agent, and 10 parts anhydrous ethanol.

[0039] The dispersant is BYK-2155; the leveling agent is BYK-331; and the defoamer is BYK-066N.

[0040] The mixed solvent comprises propylene glycol methyl ether acetate and xylene, wherein the mass ratio of propylene glycol methyl ether acetate to xylene is 2:1.

[0041] The preparation method of the rare earth modified resin includes the following steps:

[0042] S11. Add 100g of epoxy resin (EPON 828) to 200mL of tetrahydrofuran, stir, and heat to 60℃ to completely dissolve it to obtain an epoxy resin solution; dissolve 20g of diethylenetriamine in 50mL of tetrahydrofuran, and slowly add it dropwise to the epoxy resin solution, heat to 70℃ and react for 8h. After the reaction is complete, pour it into a large amount of ethanol to precipitate, filter, wash the precipitate three times with ethanol to remove unreacted diethylenetriamine, and dry under vacuum at 50℃ for 24h to obtain the first compound;

[0043] S12. Disperse 50g of the first compound in 300mL of anhydrous N,N-dimethylformamide, add 35g of ethylenediaminetetraacetic acid dianhydride, and stir the mixture at room temperature for 12h under nitrogen protection. After the reaction is complete, filter the mixture and wash it three times alternately with N,N-dimethylformamide and deionized water to completely remove unreacted ethylenediaminetetraacetic acid dianhydride. Dry the mixture under vacuum at 60℃ for 48h to obtain the second compound.

[0044] S13. Add 40g of the second compound to 500mL of deionized water and allow it to swell fully under vigorous stirring to obtain a dispersion. Under rapid stirring, slowly add 0.5mol / L cerium ammonium nitrate solution dropwise to the dispersion. After the addition is complete, heat to 60℃ and react for 6h. After the reaction is complete, centrifuge to collect the solid product, wash repeatedly with deionized water until the supernatant is colorless, and vacuum dry at 70℃ to constant weight to obtain rare earth modified resin.

[0045] The preparation method of the repair agent loading unit includes the following steps:

[0046] S21. Under ice-water bath and high-speed shear (10000 rpm), add 10g of epoxy resin (E51) to 100g of 4wt% polyvinyl alcohol aqueous solution, emulsify for 5~10 minutes to obtain epoxy emulsion, and place it in ice-water bath for later use.

[0047] S22. Melt 1.4g of m-phenylenediamine into a transparent liquid in a hot water bath at 65-70°C, add 5-10g of anhydrous ethanol, and stir until completely dissolved to obtain a transparent MPDA / ethanol solution; under ice-water bath and high-speed shear (10000rpm), use a syringe to rapidly (within 1-2 minutes) add the hot MPDA / ethanol solution dropwise to 50g of 4wt% polyvinyl alcohol aqueous solution, and continue high-speed shear for 2-3 minutes to obtain an amine emulsion;

[0048] S23. Under low-speed mechanical stirring (about 300~400 rpm) and ice-water bath conditions, the amine emulsion is slowly added dropwise to the epoxy emulsion. After the addition is complete, the speed is increased to 5000~6000 rpm, and the emulsification is carried out for 2~3 minutes to obtain the double emulsion.

[0049] S24. Immediately transfer the double emulsion to a three-necked flask, heat it to 55°C in a water bath, stir it mechanically at low speed, add 5g of urea and 2g of ammonium chloride, and after they dissolve, slowly add 15g of 37% formaldehyde solution, adjust the pH to 3.5~4.0 with acetic acid, react for 4h, filter, wash with water and ethanol to obtain the third compound;

[0050] S25. Disperse 20g of the third compound in 200mL of ethanol / water mixed solution, adjust the pH to 5.0 with acetic acid, add 10g of 3-aminopropyltriethoxysilane, react at 60℃ for 8h, filter, wash thoroughly with ethanol, and dry to obtain the repair agent loading unit.

[0051] The volume ratio of ethanol to water in the ethanol / water mixed solution is 9:1.

[0052] It's important to note that stepwise emulsification creates a double physical barrier to prevent premature cross-linking and curing of the epoxy resin and m-phenylenediamine, which could hinder subsequent crack repair. The epoxy resin is dispersed into countless tiny droplets, each encapsulated by polyvinyl alcohol molecules, forming the first layer of isolation. Similarly, the m-phenylenediamine is dispersed into another batch of tiny droplets, also encapsulated by polyvinyl alcohol, forming the second layer of isolation. When the two emulsions are mixed, a complex emulsion is formed where epoxy and amine droplets coexist, rather than a uniform mixture of epoxy and amine molecules. The reaction can only occur at the moment of accidental collision and merging of the two droplets, significantly reducing the reaction probability. Once the complex emulsion is formed, the temperature is immediately raised and urea and formaldehyde are added. The urea-formaldehyde condensation reaction proceeds rapidly at the oil-water interface, forming a dense and robust polymer shell on the surface of each epoxy and amine droplet. This shell completely physically isolates the epoxy and amine, preventing them from reacting. Pure m-phenylenediamine must be kept in a liquid state at temperatures above 65°C, which would drastically accelerate the curing reaction. When dissolved in ethanol, it can remain in a solution state at room temperature, which is far below its melting point, laying the foundation for subsequent low-temperature operations. It is then volatilized and removed during the subsequent polycondensation reaction.

[0053] Based on the same inventive concept, in a second aspect, the present invention also provides a method for preparing a rare earth-modified antibacterial coating, applicable to the preparation of the aforementioned rare earth-modified antibacterial coating, the preparation method comprising:

[0054] S31. Preparation of Component A: In the mixing tank, add the mixed solvent, dispersant, leveling agent and defoamer, stir at low speed (300~400 rpm) for 5 minutes, mix evenly, then slowly add rutile titanium dioxide and mica powder while stirring. After the addition is complete, increase the speed to 1500~2000 rpm and disperse at high speed for 20~30 minutes. Then adjust the speed back to 600~800 rpm, slowly add rare earth modified resin and stir until it is completely dissolved to form a uniform paint slurry. While maintaining the speed, slowly add the repair agent loading unit and tetraethoxysilane. After stirring for 1~2 hours, filter to obtain Component A, and package it into a barrel.

[0055] S32. Preparation of component B: In another mixing tank, add anhydrous ethanol, add dibutyltin dilaurate until completely dissolved while stirring, add polyamide 650 curing agent, stir at low speed for 20 minutes to mix evenly, filter to obtain component B, and package into small barrels;

[0056] S33. When using, mix component A and component B at a mass ratio of 5:1, stir thoroughly, and allow to mature for 15-20 minutes to obtain a rare earth modified antibacterial coating. The preparation process is as follows: Figure 1 As shown.

[0057] Example 2: This example discloses a rare earth modified antibacterial coating, comprising component A and component B; component A is the main agent; component B is the curing agent;

[0058] Component A comprises the following components in parts by weight: 100 parts rare earth modified resin, 15 parts repair agent loading unit, and 3 parts tetraethoxysilane; wherein the rare earth modified resin and the repair agent loading unit are connected by silicon-nitrogen bonds.

[0059] Component A further comprises the following components in parts by weight: 20 parts rutile titanium dioxide, 5 parts mica powder, 0.5 parts dispersant, 0.2 parts leveling agent, 0.3 parts defoamer, and 30 parts mixed solvent.

[0060] Component B comprises the following components in parts by weight: 0.06 parts dibutyltin dilaurate, 40 parts polyamide 650 curing agent, and 10 parts anhydrous ethanol.

[0061] The other components and preparation methods are the same as in Example 1.

[0062] Example 3: This example discloses a rare earth modified antibacterial coating, comprising component A and component B; component A is the main agent; component B is the curing agent;

[0063] Component A comprises the following components in parts by weight: 110 parts rare earth modified resin, 25 parts repair agent loading unit, and 5 parts tetraethoxysilane; wherein the rare earth modified resin and the repair agent loading unit are connected by silicon-nitrogen bonds.

[0064] Component A further comprises the following components in parts by weight: 30 parts rutile titanium dioxide, 10 parts mica powder, 1.5 parts dispersant, 0.5 parts leveling agent, 0.8 parts defoamer, and 50 parts mixed solvent.

[0065] Component B comprises the following components in parts by weight: 0.10 parts dibutyltin dilaurate, 42 parts polyamide 650 curing agent, and 12 parts anhydrous ethanol.

[0066] The other components and preparation methods are the same as in Example 1.

[0067] Example 4: This example discloses a rare earth modified antibacterial coating, comprising component A and component B; component A is the main agent; component B is the curing agent;

[0068] Component A comprises the following components in parts by weight: 105 parts rare earth modified resin, 20 parts repair agent loading unit, and 4 parts tetraethoxysilane; wherein the rare earth modified resin and the repair agent loading unit are connected by silicon-nitrogen bonds.

[0069] Component A further comprises the following components in parts by weight: 25 parts rutile titanium dioxide, 7.5 parts mica powder, 1.0 part dispersant, 0.35 parts leveling agent, 0.55 parts defoamer, and 40 parts mixed solvent.

[0070] Component B comprises the following components in parts by weight: 0.08 parts dibutyltin dilaurate, 41 parts polyamide 650 curing agent, and 11 parts anhydrous ethanol.

[0071] The other components and preparation methods are the same as in Example 1.

[0072] Comparative Example 1: Based on Example 1, but unlike Example 1, the rare earth modified resin in this comparative example does not introduce amino groups.

[0073] The preparation method of the rare earth modified resin includes the following steps:

[0074] S11. 50g of epoxy resin was dispersed in 300mL of anhydrous N,N-dimethylformamide, and 35g of ethylenediaminetetraacetic acid dianhydride was added. The mixture was stirred at room temperature for 12h under nitrogen protection. After the reaction was completed, the mixture was filtered and washed three times alternately with N,N-dimethylformamide and deionized water to completely remove unreacted ethylenediaminetetraacetic acid dianhydride. The mixture was then dried under vacuum at 60℃ for 48h to obtain the second compound.

[0075] S12. Add 40g of the second compound to 500mL of deionized water and allow it to swell fully under vigorous stirring to obtain a dispersion. Under rapid stirring, slowly add 0.5mol / L cerium ammonium nitrate solution dropwise to the dispersion. After the addition is complete, heat to 60℃ and react for 6h. After the reaction is complete, centrifuge to collect the solid product, wash repeatedly with deionized water until the supernatant is colorless, and vacuum dry at 70℃ to constant weight to obtain rare earth modified resin.

[0076] The other components and preparation methods are the same as in Example 1.

[0077] Comparative Example 2: Based on Example 1, but unlike Example 1, the rare earth modified resin in this comparative example is not grafted with EDTA groups.

[0078] The preparation method of the rare earth modified resin includes the following steps:

[0079] S11. Add 100g of epoxy resin (EPON 828) to 200mL of tetrahydrofuran, stir, and heat to 60℃ to completely dissolve it to obtain an epoxy resin solution; dissolve 20g of diethylenetriamine in 50mL of tetrahydrofuran, and slowly add it dropwise to the epoxy resin solution, heat to 70℃ and react for 8h. After the reaction is complete, pour it into a large amount of ethanol to precipitate, filter, wash the precipitate three times with ethanol to remove unreacted diethylenetriamine, and dry under vacuum at 50℃ for 24h to obtain the first compound;

[0080] S12. Add 40g of the first compound to 500mL of deionized water and allow it to swell fully under vigorous stirring to obtain a dispersion. Under rapid stirring, slowly add 0.5mol / L cerium ammonium nitrate solution dropwise to the dispersion. After the addition is complete, heat to 60℃ and react for 6h. After the reaction is complete, centrifuge to collect the solid product, wash repeatedly with deionized water until the supernatant is colorless, and vacuum dry at 70℃ to constant weight to obtain rare earth modified resin.

[0081] The other components and preparation methods are the same as in Example 1.

[0082] Comparative Example 3: Based on Example 1, but unlike Example 1, the repair agent loading unit in this comparative example is not grafted with silanol groups.

[0083] The preparation method of the repair agent loading unit includes the following steps:

[0084] S21. Under ice-water bath and high-speed shear (10000 rpm), add 10g of epoxy resin (E51) to 100g of 4wt% polyvinyl alcohol aqueous solution, emulsify for 5~10 minutes to obtain epoxy emulsion, and place it in ice-water bath for later use.

[0085] S22. Melt 1.4g of m-phenylenediamine into a transparent liquid in a hot water bath at 65-70°C, add 5-10g of anhydrous ethanol, and stir until completely dissolved to obtain a transparent MPDA / ethanol solution; under ice-water bath and high-speed shear (10000rpm), use a syringe to rapidly (within 1-2 minutes) add the hot MPDA / ethanol solution dropwise to 50g of 4wt% polyvinyl alcohol aqueous solution, and continue high-speed shear for 2-3 minutes to obtain an amine emulsion;

[0086] S23. Under low-speed mechanical stirring (about 300~400 rpm) and ice-water bath conditions, the amine emulsion is slowly added dropwise to the epoxy emulsion. After the addition is complete, the speed is increased to 5000~6000 rpm, and the emulsification is carried out for 2~3 minutes to obtain the double emulsion.

[0087] S24. Immediately transfer the emulsion to a three-necked flask, heat it to 55°C in a water bath, stir it mechanically at low speed, add 5g of urea and 2g of ammonium chloride, and after they dissolve, slowly add 15g of 37% formaldehyde solution. Adjust the pH to 3.5~4.0 with acetic acid, react for 4 hours, filter, wash with water and ethanol to obtain the repair agent loading unit.

[0088] The other components and preparation methods are the same as in Example 1.

[0089] Comparative Example 4: Based on Example 1, but unlike Example 1, this comparative example does not include rare earth modified resin.

[0090] Comparative Example 5: Based on Example 1, but unlike Example 1, this comparative example does not include a repair agent loading unit.

[0091] Comparative Example 6: Based on Example 1, but unlike Example 1, this comparative example does not include rare earth modified resin and repair agent loading unit.

[0092] Comparative Example 7: Based on Example 1, except that this comparative example does not include tetraethoxysilane.

[0093] Comparative Example 8: Based on Example 1, except that this comparative example does not include dibutyltin dilaurate.

[0094] Comparative Example 9: Based on Example 1, except that this comparative example does not include tetraethoxysilane and dibutyltin dilaurate.

[0095] Experimental Example 1: The coatings obtained in Examples 1-4 and Comparative Examples 1-9 were uniformly applied to sandblasted tinplate or low-carbon steel plates as substrates using a wire bar coater, controlling the wet film thickness to 150 μm. Under the same conditions (e.g., 25°C, 7 days), the coatings were fully cured, ensuring a dry film thickness of approximately 100 ± 10 μm. On the surface of all cured coating samples, a standard scratch of 2 cm in length and approximately 100 μm in width was prepared using a diamond scratch tester or a sharp blade until the metal substrate was exposed. The samples were then placed... In the accelerated test chamber (conditions: Concentration: 50 ppm; Temperature: 40°C; Relative Humidity: 95%; Exposure Time: 24 hours. Another set of samples from Experimental Example 1 were taken and exposed to the same temperature and humidity but without [the following concentrations / humidities]. The sample was placed in an atmosphere for 24 hours as a blank. Observation was performed using a scanning electron microscope (SEM). Morphological changes of the scratches before and after exposure; Fourier transform infrared spectroscopy (FT-IR) was used to test the scratch area and its vicinity. The coating surfaces before and after exposure were analyzed, with a focus on silanol groups (Si-OH) and silicon-oxygen bonds (Si-O-Si); the results are shown in Table 1.

[0096]

[0097] Based on the results in Table 1, compared with the blank, it can be seen that Example 1 showed no improvement. Gas-triggered coatings do not exhibit self-healing properties. Comparing Example 1 with Comparative Example 1, it can be concluded that rare-earth modified resins without amino groups cannot form silicon-nitrogen bonds, thus failing to produce self-healing. Comparing Example 1 with Comparative Example 2, it can be concluded that rare-earth modified resins without EDTA grafts cannot fix cerium ions, leading to catalytic failure. The efficiency of acid production is extremely low, resulting in very poor scratch repair effect. Compared with Comparative Examples 3 and 4, Example 1 shows that the absence of silicon-nitrogen bonds renders the repair function ineffective. Compared with Comparative Examples 5 and 6, Example 1 shows that the lack of a repair agent results in a loss of repair ability. Compared with Comparative Example 7, Example 1 shows that dibutyltin dilaurate promotes the formation of silicon-oxygen bonds from silanols by promoting the generation of silicon-nitrogen bonds, but the number of silanols is limited, making it impossible to form a strong re-crosslinking network. Compared with Comparative Example 8, Example 1 shows that even with the generation of a large number of silanol groups by tetraethoxysilane, the lack of dibutyltin dilaurate results in an extremely slow condensation reaction between silanols, making it impossible to form a robust network within an effective time. Compared with Comparative Example 9, Example 1 shows that only the repair agent provides repair, lacking the enhancement of re-crosslinking, resulting in fragile repair performance.

[0098] Example 2: The coatings obtained from Examples 1-4 were subjected to basic performance tests according to the method in Example 1, including adhesion (refer to ISO 2409), flexibility (refer to ISO 1519), hardness (refer to ISO 15184), corrosion resistance (refer to ASTM B117), and antibacterial properties (refer to ISO 22196). The basic performance test results of the coatings without artificial damage are shown in Table 2; the basic performance test results of the coatings after damage repair are shown in Table 3.

[0099]

[0100]

[0101] Finally, it should be noted that although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rare earth-modified antibacterial coating, characterized by, Comprise component A and component B; the component A is main agent; the component B is curing agent; The component A comprises the following components in parts by weight: 100-110 parts of rare earth modified resin, 15-25 parts of repair agent loading unit, 3-5 parts of tetraethoxysilane; wherein the rare earth modified resin and the repair agent loading unit are connected by silicon-nitrogen bond; The component A further comprises the following components in parts by weight: 20-30 parts of rutile titanium dioxide, 5-10 parts of mica powder, 0.5-1.5 parts of dispersing agent, 0.2-0.5 parts of leveling agent, 0.3-0.8 parts of defoaming agent and 30-50 parts of mixed solvent; The component B comprises the following components in parts by weight: 0.06-0.10 parts of dibutyltin dilaurate, 40-42 parts of polyamide 650 curing agent, 10-12 parts of anhydrous ethanol; The preparation method of the rare earth modified resin comprises the following steps: S11. Add epoxy resin into tetrahydrofuran, stir, and heat to completely dissolve to obtain an epoxy resin solution; dissolve diethylenetriamine in tetrahydrofuran, slowly drop into the epoxy resin solution, heat to react, after the reaction is completed, pour into a large amount of ethanol to precipitate, extract filter, wash the precipitate with ethanol, and vacuum dry to obtain a first compound; S12. Disperse the first compound in anhydrous N,N-dimethylformamide, add ethylenediaminetetraacetic dianhydride, stir to react under nitrogen protection, after the reaction is completed, extract filter, wash with N,N-dimethylformamide and deionized water alternately, and vacuum dry to obtain a second compound; S13. Add the second compound into deionized water, fully swell under vigorous stirring to obtain a dispersion liquid; slowly drop 0.5 mol / L cerium ammonium nitrate solution into the dispersion liquid under rapid stirring, after the dropping is completed, heat to react, after the reaction is completed, centrifugal collect the solid product, repeatedly wash with deionized water until the supernatant is colorless, and vacuum dry to constant weight to obtain a rare earth modified resin; The preparation method of the repair agent loading unit comprises the following steps: S21. Under ice water bath and high-speed shearing, add epoxy resin into 4wt% polyvinyl alcohol aqueous solution to emulsify to obtain an epoxy emulsion, and place in ice water bath for standby; S22. Melt m-phenylenediamine in hot water bath, add anhydrous ethanol, stir to completely dissolve to obtain MPDA / ethanol solution; under ice water bath and high-speed shearing, quickly drop the hot MPDA / ethanol solution into 4wt% polyvinyl alcohol aqueous solution, and continue to high-speed shear to obtain amine emulsion; S23. Under low-speed mechanical stirring and ice water bath, slowly drop the amine emulsion into the epoxy emulsion to re-emulsify to obtain a re-emulsion; S24. Immediately transfer the re-emulsion into a three-necked flask, heat in water bath, low-speed stir, add urea and ammonium chloride, after dissolving, slowly drop 37% formaldehyde solution, adjust pH to 3.5-4.0, after the reaction is completed, extract filter, wash with water and ethanol to obtain a third compound; S25. The third compound is dispersed in an ethanol / water mixed solution, the pH is adjusted to 5.0, 3-aminopropyl triethoxysilane is added, after the reaction is completed, the mixture is filtered, washed with ethanol and dried to obtain the repair agent loading unit.

2. The rare earth modified antibacterial coating according to claim 1, characterized in that, The dispersant is BYK-2155; the leveling agent is BYK-331; and the defoaming agent is BYK-066N.

3. The rare earth modified antibacterial coating according to claim 1, characterized in that, The mixed solvent comprises propylene glycol methyl ether acetate and xylene, and the mass ratio of the propylene glycol methyl ether acetate to xylene is 1-3:

1.

4. The rare earth modified antibacterial coating according to claim 1, characterized in that, The volume ratio of ethanol to water in the ethanol / water mixed solution is 9:

1.

5. A preparation method of the rare earth modified antibacterial coating, which is applied to the preparation of the rare earth modified antibacterial coating according to any one of claims 1-4, characterized in that, The preparation method comprises: S31. Preparation of component A: in a batching tank, the mixed solvent, dispersant, leveling agent and defoaming agent are added, stirred at low speed, mixed uniformly, then the rutile titanium dioxide and mica powder are slowly added while stirring, after the addition is completed, the stirring speed is increased, high-speed dispersion is performed, the rare earth modified resin is slowly added, stirred until it is completely dissolved, then the repair agent loading unit and tetraethoxysilane are slowly added, stirred and filtered to obtain component A, which is packaged into a barrel; S32. Preparation of component B: in another batching tank, anhydrous ethanol is added, dibutyltin dilaurate is added under stirring until it is completely dissolved, and the polyamide 650 curing agent is added, stirred at low speed until it is mixed uniformly, then filtered to obtain component B, which is packaged into a small barrel; S33. In use, component A and component B are mixed in a mass ratio of 5:1, stirred thoroughly, aged and a rare earth modified antibacterial coating is obtained.

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